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Hot Jupiters are a class of gas giant exoplanets that are inferred to be physically similar to Jupiter but that have very short orbital period (P<10 days). The close proximity to their stars and high surface-atmosphere temperatures resulted in the moniker "hot Jupiters". Hot Jupiters are the easiest extrasolar planets to detect via the radial-velocity method, because the oscillations they induce in their parent stars' motion are relatively large and rapid compared to those of other known types of planets. One of the best-known hot Jupiters is 51 Pegasi b. Discovered in 1995, it was the first extrasolar planet found orbiting a Sun-like star. 51 Pegasi b has an orbital period of about 4 days. Though there is diversity among hot Jupiters, they do share some common properties. - Their defining characteristics are their large masses and short orbital periods, spanning 0.36–11.8 Jupiter masses and 1.3–111 Earth days. The mass cannot be greater than approximately 13.6 Jupiter masses because then the planet would start burning deuterium and become a brown dwarf. - Most have nearly circular orbits (low eccentricities). It is thought that their orbits are circularized by perturbations from nearby stars or tidal forces. - Many have unusually low densities. The lowest one measured thus far is that of TrES-4 at 0.222 g/cm3. The large radii of hot Jupiters are not yet fully understood but it is thought that the expanded envelopes can be attributed to high stellar irradiation, high atmospheric opacities, possible internal energy sources, and orbits close enough to their stars for the outer layers of the planets to exceed their Roche limit and be pulled further outward. - They are likely to have extreme and exotic atmospheres due to their short periods, relatively long days, and tidal locking. Atmospheric dynamics models predict strong vertical stratification with intense winds and super-rotating equatorial jets driven by radiative forcing and the transfer of heat and momentum. The day-night temperature difference at the photosphere is predicted to be substantial, approximately 500 K for a model based on HD 209458b. - They appear to be more common around F- and G-type stars and less so around K-type stars. Hot Jupiters around red dwarfs are very rare. Generalizations about the distribution of these planets must take into account the various observational biases. Formation and evolution There are two general schools of thought regarding the origin of hot Jupiters: formation at a distance followed by inward migration and in-situ formation at the distances at which they're currently observed. The prevalent view is migration. In the migration hypothesis, a hot Jupiter forms beyond the frost line, from rock, ice, and gases via the core accretion method of planetary formation. The planet then migrates inwards to the star where it eventually forms a stable orbit. The planet may have migrated inward smoothly via type II orbital migration. Or it may have migrated more suddenly due to gravitational scattering onto eccentric orbits during an encounter with another massive planet, followed by the circularization and shrinking of the orbits due to tidal interactions with the star. A hot Jupiter's orbit could also have been altered via the Kozai mechanism, causing an exchange of inclination for eccentricity resulting in a high eccentricity low perihelion orbit, in combination with tidal friction. This requires a massive body—another planet or a stellar companion—on a more distant and inclined orbit; approximately 50% of hot Jupiters have distant Jupiter-mass or larger companions, which can leave the hot Jupiter with an orbit inclined relative to the star's rotation. The type II migration happens during the solar nebula phase, i.e. when gas is still present. Energetic stellar photons and strong stellar winds at this time remove most of the remaining nebula. Migration via the other mechanism can happen after the loss of the gas disk. Instead of being gas giants that migrated inward, in an alternate hypothesis the cores of the hot Jupiters began as more common super-Earths which accreted their gas envelopes at their current locations, becoming gas giants in situ. The super-Earths providing the cores in this hypothesis could have formed either in situ or at greater distances and have undergone migration before acquiring their gas envelopes. Since super-Earths are often found with companions, the hot Jupiters formed in situ could also be expected to have companions. The increase of the mass of the locally growing hot Jupiter has a number of possible effects on neighboring planets. If the hot Jupiter maintains an eccentricity greater than 0.01, sweeping secular resonances can increase the eccentricity of a companion planet, causing it to collide with the hot Jupiter. The core of the hot Jupiter in this case would be unusually large. If the hot Jupiter's eccentricity remains small the sweeping secular resonances could also tilt the orbit of the companion. Traditionally, the in situ mode of conglomeration has been disfavored because the assembly of massive cores, which is necessary for the formation of hot Jupiters, requires surface densities of solids ≈ 104 g/cm2, or larger. Recent surveys, however, have found that the inner regions of planetary systems are frequently occupied by super-Earth type planets. If these super-Earths formed at greater distances and migrated closer, the formation of in situ hot Jupiters is not entirely in situ. If the atmosphere of a hot Jupiter is stripped away via hydrodynamic escape, its core may become a chthonian planet. The amount of gas removed from the outermost layers depends on the planet's size, the gases forming the envelope, the orbital distance from the star, and the star's luminosity. In a typical system, a gas giant orbiting at 0.02 AU around its parent star loses 5–7% of its mass during its lifetime, but orbiting closer than 0.015 AU can mean evaporation of a substantially larger fraction of the planet's mass. It should be noted that no such objects have been found yet and they are still hypothetical. Terrestrial planets in systems with hot Jupiters Simulations have shown that the migration of a Jupiter-sized planet through the inner protoplanetary disk (the region between 5 and 0.1 AU from the star) is not as destructive as one might assume. More than 60% of the solid disk materials in that region are scattered outward, including planetesimals and protoplanets, allowing the planet-forming disk to reform in the gas giant's wake. In the simulation, planets up to two Earth masses were able to form in the habitable zone after the hot Jupiter passed through and its orbit stabilized at 0.1 AU. Due to the mixing of inner-planetary-system material with outer-planetary-system material from beyond the frost line, simulations indicated that the terrestrial planets that formed after a hot Jupiter's passage would be particularly water-rich. In 2015, two planets were discovered around WASP-47. One was potentially a large terrestrial planet, of less than 22 Earth masses and 1.8 Earth radii. The other is of similar mass at 15.2 Earth masses, but with 3.6 Earth radii it is almost certainly a gas giant. They orbit on either side of a previously discovered hot Jupiter, with the smaller, terrestrial planet closer in. A similar orbital architecture is also exhibited by the Kepler-30 system. It has been found that several hot Jupiters have retrograde orbits and this calls into question the theories about the formation of planetary systems, although rather than a planet's orbit having been disturbed, it may be that the star itself flipped over early in their system's formation due to interactions between the star's magnetic field and the planet-forming disc. By combining new observations with the old data it was found that more than half of all the hot Jupiters studied have orbits that are misaligned with the rotation axis of their parent stars, and six exoplanets in this study have retrograde motion. Recent research has found that several hot Jupiters are in misaligned systems. This misalignment may be related to the heat of the photosphere the hot Jupiter is orbiting. There are many proposed theories as to why this might occur. One such theory involves tidal dissipation and suggests there is a single mechanism for producing hot Jupiters and this mechanism yields a range of obliquities. Cooler stars with higher tidal dissipation damps the obliquity (explaining why hot Jupiters orbiting cooler stars are well aligned) while hotter stars do not damp the obliquity (explaining the observed misalignment). Five ultra-short-period planet candidates have been identified in the region of the Milky Way known as the galactic bulge. They were observed by the Hubble Space Telescope and first described by researchers from the Space Telescope Science Institute, the Universidad Catolica de Chile, Uppsala University, the High Altitude Observatory, the INAF–Osservatorio Astronomico di Padova, and the University of California, Los Angeles. Gas giants with a large radius and very low density are sometimes called "puffy planets" or "hot Saturns", due to their density being similar to Saturn's. Puffy planets orbit close to their stars so that the intense heat from the star combined with internal heating within the planet will help inflate the atmosphere. Six large-radius low-density planets have been detected by the transit method. In order of discovery they are: HAT-P-1b, COROT-1b, TrES-4, WASP-12b, WASP-17b, and Kepler-7b. Some hot Jupiters detected by the radial-velocity method may be puffy planets. Most of these planets are below two Jupiter masses as more massive planets have stronger gravity keeping them at roughly Jupiter's size. Even when taking surface heating from the star into account, many transiting hot Jupiters have a larger radius than expected. This could be caused by the interaction between atmospheric winds and the planet's magnetosphere creating an electric current through the planet that heats it up, causing it to expand. The hotter the planet, the greater the atmospheric ionization, and thus the greater the magnitude of the interaction and the larger the electric current, leading to more heating and expansion of the planet. This theory matches the observation that planetary temperature is correlated with inflated planetary radii. Theoretical research suggests that hot Jupiters are unlikely to have moons, due to both a small Hill sphere and the tidal forces of the stars they orbit, which would destabilize any satellite's orbit, the latter process being stronger for larger moons. This means that for most hot Jupiters, stable satellites would be small asteroid-sized bodies. In spite of this, observations of WASP-12b suggest that it is orbited by at least 1 large exomoon. Hot Jupiters around red giants It has been proposed that gas giants orbiting red giants at distances similar to that of Jupiter could be hot Jupiters due to the intense irradiation they would receive from their stars. It is very likely that in the Solar System Jupiter will become a hot Jupiter after the transformation of the Sun into a red giant. The recent discovery of particularly low density gas giants orbiting red giant stars supports this theory. Hot Jupiters orbiting red giants would differ from those orbiting main-sequence stars in a number of ways, most notably the possibility of accreting material from the stellar winds of their stars and, assuming a fast rotation (not tidally locked to their stars), a much more evenly distributed heat with many narrow-banded jets. 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Generally speaking, tools that require a sharp edge are made using cryptocrystalline materials that fracture in an easily controlled conchoidal manner. Cryptocrystalline tool stones include flint and chert, which are fine-grained sedimentary materials; rhyolite and felsite, which are igneous flowstones; and obsidian, a form of natural glass created by igneous processes. These materials fracture in a predictable fashion, and are easily resharpened. For more information on this subject, see lithic reduction. Large-grained materials, such as basalt, granite, and sandstone, may also be used as tool stones, but for a very different purpose: they are ideal for ground stone artifacts. Whereas cryptocrystalline materials are most useful for killing and processing animals, large-grained materials are usually used for processing plant matter. Their rough faces often make excellent surfaces for grinding plant seeds. With much effort, some large-grained stones may be ground down into awls, adzes, and axes. In archaeology, a celt is a long, thin, prehistoric, stone or bronze tool similar to an adze, a hoe or axe-like tool.Chopping tool In archaeology a chopping tool is a stone tool. Stone tools have been dated using scientific dating such as Carbon 14 dating and Potassium argon dating. Stone tools have been found to be almost 2 million years old. Chopping tools have been found to be about 2 million years old as well. The oldest object in the British Museum is a Chopping Tool. It was found in the Olduvai Gorge in Tanzania. Since Chopping tools are a sub category of stone tools we can see how these tools have developed over time. Looking at how these tools are made is an important part in the history of the Chopping Tool. A large hard stone was needed as well as a softer stone that would be made into the chopper. The soft stone was commonly basalt (volcanic rock). The large hard stone acted as a hammer as it was hit against the soft stone. The soft stone would begin to chip away. The maker of the chopping tool would use the hard stone to create the edges and point needed to make the chopping tool efficient. Double sided sharp edges and a point are a common form of the chopping tool. The look is Similar to a Native American Projectile point, except that a chopping tool was used for stationary objects. The use of the chopping tool varied from place to place just like any other archaeological artifact. Depending on what the maker of the chopping tool made or ate depended on what the chopping tool was used for. Most commonly the chopping tool was used for food purposes. They could be used for cutting down tree branches to get to fruits or to cut large plants that could be used for food. Anything that requires a knife today could have been replaced with a chopping tool. They were also used to help assist the maker in cutting the meat of the animals. Just like butchers today, skinning and cleaning of all the meat that we eat is needed. The chopping tool helped assist hunters gather the meat, especially from large animals that were hard to carry back to the location they were staying at, and make it edible for them to consume. Another use for the chopping tool was to smash bones. Bone marrow is a good source of nutrients to help your body function. For hunters and gatherers this was important since the next source of food could have been days to weeks away. When they would hunt animals they would use the sharp edge to cut the meat off the bones and then the back edge was hard enough to smash and crush bones. Once the bones were crushed the marrow could be collected. The flakes that were chipped off the soft rock did not go to waste. Many of the thick sharp pieces were used as small knives to do very light cutting tasks. The flakes were a very important part of everyday life just like the chopping tool. Both pieces were used in everyday life to help with survival. The idea of the chopping tool spread from people to people throughout the land. In Asia stone tools did not develop as much as other places in the world. To make these tools like the chopping tool you have to have specific types of rock such as flint and jasper. In Asia these rocks were hard to find but the amount of the coarse-grained rocks and material was much easier to find. Even though the materials they used such as volcanic material and petrified wood wasn't as strong or as easy to shape they still were able to make tools that resembled the chopping tool and they were used in very similar ways. Many of the tools that were found in Asia, they were found in the Choukoutienian caves. The Choukoutienian industry is where a lot of the stone tools in Asia started. The caves are filled with many artifacts and the early chopping tool is one of the many artifacts found. The resources used to make many variations of the chopping tool were present in much of the world. Even if the items that were used to make the chopping tool in various parts of the world were not as durable or as powerful or sharp they still were used for cutting items as well as day to day survival.Cumberland point A Cumberland point is a lithic projectile point, attached to a spear and used as a hunting tool. These sturdy points were intended for use as thrusting weapons and employed by various mid-Paleo-Indians (c. 11,000 BP) in the Southeastern US in the killing of large game mammals.Eraillure In lithic analysis (a subdivision of archaeology), an eraillure is a flake removed from a lithic flake's bulb of force, which is a lump left on the ventral surface of a flake after it is detached from a core of tool stone during the process of lithic reduction. The mechanics of eraillure formation are related to the propagation of a Hertzian cone of force through the cryptocrystalline matrix of the stone, but the particulars are poorly understood. Eraillures usually form only when a hammerstone is used for lithic reduction, and then only occasionally; use of 'soft' hammer fabricators made from bone, antler, and wood produce different flake characteristics but may also produce an eraillure in rare cases.Grattoir de côté A Grattoir de côté (translates from French as Side Scraper) is an archaeological term for a ridged variety of steep-scrapers distinguished by a working edge on one side. They were found at various archaeological sites in Lebanon including Ain Cheikh and Jdeideh II and are suggested to date to Upper Paleolithic stages three or four (Antelian).Grinding slab In archaeology, a grinding slab is a ground stone artifact generally used to grind plant materials into usable size, though some slabs were used to shape other ground stone artifacts. Some grinding stones are portable; others are not and, in fact, may be part of a stone outcropping. Grinding slabs used for plant processing typically acted as a coarse surface against which plant materials were ground using a portable hand stone, or mano ("hand" in Spanish). Variant grinding slabs are referred to as metates or querns, and have a ground-out bowl. Like all ground stone artifacts, grinding slabs are made of large-grained materials such as granite, basalt, or similar tool stones.Ground stone In archaeology, ground stone is a category of stone tool formed by the grinding of a coarse-grained tool stone, either purposely or incidentally. Ground stone tools are usually made of basalt, rhyolite, granite, or other cryptocrystalline and igneous stones whose coarse structure makes them ideal for grinding other materials, including plants and other stones.Hammerstone In archaeology, a hammerstone is a hard cobble used to strike off lithic flakes from a lump of tool stone during the process of lithic reduction. The hammerstone is a rather universal stone tool which appeared early in most regions of the world including Europe, India and North America. This technology was of major importance to prehistoric cultures before the age of metalworking.Hand axe A hand axe (or handaxe) is a prehistoric stone tool with two faces that is the longest-used tool in human history. It is usually made from flint or chert. It is characteristic of the lower Acheulean and middle Palaeolithic (Mousterian) periods. Its technical name (biface) comes from the fact that the archetypical model is generally bifacial Lithic flake and almond-shaped (amygdaloidal). Hand axes tend to be symmetrical along their longitudinal axis and formed by pressure or percussion. The most common hand axes have a pointed end and rounded base, which gives them their characteristic shape, and both faces have been knapped to remove the natural cortex, at least partially. Hand axes are a type of the somewhat wider biface group of two-faced tools or weapons. Hand axes were the first prehistoric tools to be recognized as such: the first published representation of a hand axe was drawn by John Frere and appeared in a British publication in 1800. Until that time, their origins were thought to be natural or supernatural. They were called thunderstones, because popular tradition held that they had fallen from the sky during storms or were formed inside the earth by a lightning strike and then appeared at the surface. They are used in some rural areas as an amulet to protect against storms. Hand axe tools were possibly used to butcher animals; to dig for tubers, animals and water; to chop wood and remove tree bark; to throw at prey; and as a source for flake tools.Hertzian cone A Hertzian cone is the cone produced when an object passes through a solid, such as a bullet through glass. More technically, it is a cone of force that propagates through a brittle, amorphous or cryptocrystalline solid material from a point of impact. This force eventually removes a full or partial cone in the material. This is the physical principle that explains the form and characteristics of the flakes removed from a core of tool stone during the process of lithic reduction. This phenomenon is named after the German physicist Heinrich Rudolf Hertz, who first described this type of wave-front propagation through various media. Although it might not be agreed by all, natural phenomena which have been grouped with the Hertzian cone phenomena include the crescentic "chatter marks" made on smoothed bedrock by glacial ice dragging along boulders at its base, the numerous crescentic impact marks sometimes seen on pebbles and cobbles, and the shatter cones found at bolide impact sites. James Byous, working independently (at privately funded Dowd Research, Savannah, Georgia USA) has made a protracted study of Hertzian cones. Some of his work may be found via sharing points or directly at Dowd Research. He has produced a comprehensive glossary on Hertzian fractures and related terms. A Hertzian cone is often 104 degrees when created by an indenter. Smaller cones may be produced due to lack of size of the material, or irregularities in the structure of the material. However, in ballistics the faster the projectile the steeper the edges and angle of the cone.Lithic core In archaeology, a lithic core is a distinctive artifact that results from the practice of lithic reduction. In this sense, a core is the scarred nucleus resulting from the detachment of one or more flakes from a lump of source material or tool stone, usually by using a hard hammer percussor such as a hammerstone. The core is marked with the negative scars of these flakes. The surface area of the core which received the blows necessary for detaching the flakes is referred to as the striking platform. The core may be discarded or shaped further into a core tool, such as can be seen in some types of handaxe. The purpose of lithic reduction may be to rough out a blank for later refinement into a projectile point, knife, or other stone tool, or it may be performed in order to obtain sharp flakes, from which a variety of simple tools can be made. Generally, the presence of a core is indicative of the latter process, since the former process usually leaves no core. Because the morphology of cores will influence the shape of flakes, by studying the core surface morphology, we might be able to know more information about the dimensional flake attribute, including their length and thickness. Cores may be subdivided into specific types by a lithic analyst. Type frequencies, as well as the general types of materials at an archaeological site, can give the lithic analyst a better understanding of the lithic reduction processes occurring at that site. Lithic Cores may be multidirectional, conical, cylindrical, biconical, or bifacial. A multidirectional core is the product of any random rock, from which flakes were taken based on the geometry of the rock in any pattern until no further flakes could be removed. Often, multidirectional cores are used in this way until no obvious platforms are present, and then are reduced through bipolar reduction, until the core itself is too small to produce useful flakes. Conical cores have a definite pattern. One flake was removed from a narrow end of the tool stone, and this was then used as the platform to take flakes off in a unifacial fashion all around the edge of the rock. The end result is a cone-like shape. Cylindrical lithic cores are made in a similar fashion, but there is a platform on both ends of the toolstone, with flakes going up and down the side of the cylinder from either direction. Biconical cores have several platforms around the edge of the stone, with flakes taken alternately from either side, resulting in what looks like a pair of cones stuck together at the bases.Bifacial cores are similar to biconical cores, except that instead of forming a pair of cones, the flakes are taken off in such a way that the core itself grows thinner, without the edges shrinking much. Bifacial cores are usually further reduced into trade bifaces, biface blanks, or bifacial tools. Bifacial cores have been recognized as a technology allowing for efficient material usage(specifically in the creation of edge scrapers) and for their suitability for highly mobile hunter gatherer groups in need of tools made of high quality lithic materials.Lithic flake In archaeology, a lithic flake is a "portion of rock removed from an objective piece by percussion or pressure," and may also be referred to as a chip or spall, or collectively as debitage. The objective piece, or the rock being reduced by the removal of flakes, is known as a core. Once the proper tool stone has been selected, a percussor or pressure flaker (e.g., an antler tine) is used to direct a sharp blow, or apply sufficient force, respectively, to the surface of the stone, often on the edge of the piece. The energy of this blow propagates through the material, often (but not always) producing a Hertzian cone of force which causes the rock to fracture in a controllable fashion. Since cores are often struck on an edge with a suitable angle (x<90°) for flake propagation, the result is that only a portion of the Hertzian cone is created. The process continues as the flintknapper detaches the desired number of flakes from the core, which is marked with the negative scars of these removals. The surface area of the core which received the blows necessary for detaching the flakes is referred to as the striking platform.Lithic reduction In archaeology, in particular of the Stone Age, lithic reduction is the process of fashioning stones or rocks from their natural state into tools or weapons by removing some parts. It has been intensely studied and many archaeological industries are identified almost entirely by the lithic analysis of the precise style of their tools and the chaîne opératoire of the reduction techniques they used. Normally the starting point is the selection of a piece of tool stone that has been detached by natural geological processes, and is an appropriate size and shape. In some cases solid rock or larger boulders may be quarried and broken into suitable smaller pieces, and in others the starting point may be a piece of the debitage, a flake removed from a previous operation to make a larger tool. The selected piece is called the lithic core (also known as the "objective piece"). A basic distinction is that between flaked or chipped stone, the main subject here, and ground stone objects made by grinding. Flaked stone reduction involves the use of a hard hammer percussor, such as a hammerstone, a soft hammer fabricator (made of wood, bone or antler), or a wood or antler punch to detach lithic flakes from the lithic core. As flakes are detached in sequence, the original mass of stone is reduced; hence the term for this process. Lithic reduction may be performed in order to obtain sharp flakes, of which a variety of tools can be made, or to rough out a blank for later refinement into a projectile point, knife, or other object. Flakes of regular size that are at least twice as long as they are broad are called blades. Lithic tools produced this way may be bifacial (exhibiting flaking on both sides) or unifacial (exhibiting flaking on one side only). Cryptocrystalline or amorphous stone such as chert, flint, obsidian, and chalcedony, as well as other fine-grained stone material, such as rhyolite, felsite, and quartzite, were used as a source material for producing stone tools. As these materials lack natural planes of separation, conchoidal fractures occur when they are struck with sufficient force; for these stones this process is called knapping. The propagation of force through the material takes the form of a Hertzian cone that originates from the point of impact and results in the separation of material from the objective piece, usually in the form of a partial cone, commonly known as a lithic flake. This process is predictable, and allows the flintknapper to control and direct the application of force so as to shape the material being worked. Controlled experiments may be performed using glass cores and consistent applied force in order to determine how varying factors affect core reduction.It has been shown that stages in the lithic reduction sequence may be misleading and that a better way to assess the data is by looking at it as a continuum. The assumptions that archaeologists sometimes make regarding the reduction sequence based on the placement of a flake into a stage can be unfounded. For example, a significant amount of cortex can be present on a flake taken off near the very end of the reduction sequence. Removed flakes exhibit features characteristic of conchoidal fracturing, including striking platforms, bulbs of force, and occasionally eraillures (small secondary flakes detached from the flake's bulb of force). Flakes are often quite sharp, with distal edges only a few molecules thick when they have a feather termination. These flakes can be used directly as tools or modified into other utilitarian implements, such as spokeshaves and scrapers.Pesse canoe The Pesse canoe is believed to be the world's oldest known boat, and certainly the oldest known canoe. Carbon dating indicates that the boat was constructed during the early mesolithic period between 8040 BCE and 7510 BCE. It is now in the Drents Museum in Assen, Netherlands.Plano point In archeology, Plano point is flaked stone projectile points and tools created by the various Plano cultures of the North American Great Plains between 9000 BC and 6000 BC for hunting, and possibly to kill other humans. They are bifacially worked and have been divided into numerous sub-groups based on variations in size, shape and function including Alberta points, Cody points, Frederick points, Eden points and Scottsbluff points. Plano points do not include the hollowing or 'fluting' found in Clovis and Folsom points.Racloir In archeology, a racloir, also known as racloirs sur talon (French for scraper on the platform), is a certain type of flint tool made by prehistoric peoples. It is a type of side scraper distinctive of Mousterian assemblages. It is created from a flint flake and looks like a large scraper. As well as being used for scraping hides and bark, it may also have been used as a knife. Racloirs are most associated with the Neanderthal Mousterian industry. These racloirs are retouched along the ridge between the striking platform and the dorsal face. They have shaped edges and are modified by abrupt flaking from the dorsal face.Stone tool A stone tool is, in the most general sense, any tool made either partially or entirely out of stone. Although stone tool-dependent societies and cultures still exist today, most stone tools are associated with prehistoric (particularly Stone Age) cultures that have become extinct. Archaeologists often study such prehistoric societies, and refer to the study of stone tools as lithic analysis. Ethnoarchaeology has been a valuable research field in order to further the understanding and cultural implications of stone tool use and manufacture.Stone has been used to make a wide variety of different tools throughout history, including arrow heads, spearpoints and querns. Stone tools may be made of either ground stone or chipped stone, and a person who creates tools out of the latter is known as a flintknapper. Chipped stone tools are made from cryptocrystalline materials such as chert or flint, radiolarite, chalcedony, obsidian, basalt, and quartzite via a process known as lithic reduction. One simple form of reduction is to strike stone flakes from a nucleus (core) of material using a hammerstone or similar hard hammer fabricator. If the goal of the reduction strategy is to produce flakes, the remnant lithic core may be discarded once it has become too small to use. In some strategies, however, a flintknapper reduces the core to a rough unifacial or bifacial preform, which is further reduced using soft hammer flaking techniques or by pressure flaking the edges. More complex forms of reduction include the production of highly standardized blades, which can then be fashioned into a variety of tools such as scrapers, knives, sickles and microliths. In general terms, chipped stone tools are nearly ubiquitous in all pre-metal-using societies because they are easily manufactured, the tool stone is usually plentiful, and they are easy to transport and sharpen.Uniface In archeology, a uniface is a specific type of stone tool that has been flaked on one surface only. There are two general classes of uniface tools: modified flakes—and formalized tools, which display deliberate, systematic modification of the marginal edges, evidently formed for a specific purpose.Yubetsu technique The Yubetsu technique (湧別技法, Yūbetsu gihō) is a special technique to make microblades, proposed by Japanese scholar Yoshizaki in 1961, based on his finds in some Upper Palaeolithic sites in Hokkaido, Japan, which date from c. 13,000 bp. The name comes from the Yūbetsu River (湧別川, Yubetsugawa), on the right bank of which the Shirataki (白滝遺跡, Shirataki Iseki) Palaeolithic sites were discovered. To make microblades by this technique, a large biface is made into a core which looks like a tall carinated scraper. Then one lateral edge of the bifacial core is removed, producing at first a triangular spall. After, more edge removals will produce ski spalls of parallel surfaces. This technique was also used from Mongolia to Kamchatka Peninsula during the later Pleistocene.
Airbreathing jet engine An airbreathing jet engine (or ducted jet engine) is a jet engine propelled by a jet of hot exhaust gases formed from heated and expanded air that is drawn into the engine via a compressor, typically a centrifugal or axial type. They are typically gas turbine engines. The opposite of airbreathing jet engines are non-airbreathing jet engines, such as rocket engines, for example, which are propelled by a jet of hot gases created by the chemical reaction of two or more compounds internally. While the majority of the mass flow of an airbreathing jet engine is provided by air taken from outside of the engine and heated internally, using energy stored in the form of fuel, a rocket engine's fuel provides both the energy and the mass flow to create thrust. All practical airbreathing jet engines are internal combustion engines that directly heat the air by burning fuel, with the resultant hot gases used for propulsion via a propulsive nozzle, although other techniques for heating the air have been experimented with (such as nuclear jet engines). Most modern jet engine designs are turbofans, which have largely replaced turbojets. These modern engines use a gas turbine engine core with high overall pressure ratio (about 40:1 in 1995) and high turbine entry temperature (about 1800 K in 1995), and provide a great deal of their thrust with a turbine-power fan stage, rather than with pure exhaust thrust as in a turbojet. These features combine to give a high efficiency, relative to a turbojet. A few jet engines use simple ram effect (ramjet) or pulse combustion (pulsejet) to give compression. - 1 Background - 2 Types of airbreathing jet engines - 3 Major components - 4 Operation - 5 Safety and reliability - 6 Economic considerations - 7 Environmental considerations - 8 Advanced designs - 9 Terminology - 10 See also - 11 References The original air-breathing gas turbine jet engine was the turbojet. It was a concept brought to life by two engineers, Frank Whittle in England United Kingdom and Hans von Ohain in Germany. The turbojet compresses and heats air and then exhausts it as a high speed, high temperature jet to create thrust. While these engines are capable of giving high thrust levels, they are most efficient at very high speeds (over Mach 1), due to the low-mass-flow, high speed nature of the jet exhaust. Modern turbofans are a development of the turbojet; they are basically a turbojet that includes a new section called the fan stage. Rather than using all of its exhaust gases to provide direct thrust like a turbojet, the turbofan engine extracts some of the power from the exhaust gases inside the engine and uses it to power the fan stage. The fan stage accelerates a large volume of air through a duct, bypassing the engine core (the actual gas turbine component of the engine), and expelling it at the rear as a jet, creating thrust. A proportion of the air that comes through the fan stage enters the engine core rather than being ducted to the rear, and is thus compressed and heated; some of the energy is extracted to power the compressors and fans, while the remainder is exhausted at the rear. This high-speed, hot-gas exhaust blends with the low speed, cool-air exhaust from the fan stage, and both contribute to the overall thrust of the engine. Depending on what proportion of cool air is bypassed around the engine core, a turbofan can be called low-bypass, high-bypass, or very-high-bypass engines. Low bypass engines were the first turbofan engines produced, and provide the majority of their thrust from the hot core exhaust gases, while the fan stage only supplements this. These engines are still commonly seen on military fighter aircraft, since they provide more efficient thrust at supersonic speeds and have a narrower frontal area, minimizing aerodynamic drag. Their comparatively high noise levels and subsonic fuel consumption are deemed acceptable in such an application, whereas although the first generation of turbofan airliners used low-bypass engines, their high noise levels and fuel consumption mean they have fallen out of favor for large aircraft. High bypass engines have a much larger fan stage, and provide most of their thrust from the ducted air of the fan; the engine core provides power to the fan stage, and only a proportion of the overall thrust comes from the engine core exhaust stream. A high-bypass turbofan functions very similarly to a turboprop engine, except it uses a many-bladed fan rather than a multi-blade propeller, and relies on a duct to properly vector the airflow to create thrust. Over the last several decades, there has been a move towards very high bypass engines, which use fans far larger than the engine core itself, which is typically a modern, high efficiency two or three-spool design. This high efficiency and power is what allows such large fans to be viable, and the increased thrust available (up to 75,000lbs per engine in engines such as the Rolls-Royce Trent XWB or General Electric GENx), have allowed a move to large twin engine aircraft, such as the Airbus A350 or Boeing 777, as well as allowing twin engine aircraft to operate on long overwater routes, previously the domain of 3-engine or 4-engine aircraft. Jet engines were designed to power aircraft, but have been used to power jet cars and jet boats for speed record attempts, and even for commercial uses such as by railroads for clearing snow and ice from switches in railyards (mounted in special rail cars), and by race tracks for drying off track surfaces after rain (mounted in special trucks with the jet exhaust blowing onto the track surface). Types of airbreathing jet engines Airbreathing jet engines are nearly always internal combustion engines that obtain propulsion from the combustion of fuel inside the engine. Oxygen present in the atmosphere is used to oxidise a fuel source, typically a hydrocarbon-based jet fuel. The burning mixture expands greatly in volume, driving heated air through a propelling nozzle. Gas turbine powered engines: Ram powered jet engine: Pulsed combustion jet engine: Turbojets consist of an inlet, a compressor, a combustor, a turbine (that drives the compressor) and a propelling nozzle. The compressed air is heated in the combustor and passes through the turbine, then expands in the nozzle to produce a high speed propelling jet Turbojets have a low propulsive efficiency below about Mach 2 and produce a lot of jet noise, both a result of the very high velocity of the exhaust. Modern jet propelled aircraft are powered by turbofans. These engines, with their lower exhaust velocities, produce less jet noise and use less fuel. Turbojets are still used to power medium range cruise missiles, due to their high exhaust speed, low frontal area and relative simplicity. Most modern jet engines are turbofans. The low pressure compressor(LPC), usually known as a fan, compresses air into a bypass duct whilst its inner portion supercharges the core compressor. The fan is often an integral part of a multi-stage core LPC. The bypass airflow either passes to a separate 'cold nozzle' or mixes with low pressure turbine exhaust gases, before expanding through a 'mixed flow nozzle'. In the 1960s there was little difference between civil and military jet engines, apart from the use of afterburning in some (supersonic) applications. Today, turbofans are used for airliners because they have an exhaust speed that is better matched to the subsonic flight speed of the airliner. At airliner flight speeds, the exhaust speed from a turbojet engine is excessively high and wastes energy. The lower exhaust speed from a turbofan gives better fuel consumption. The increased airflow from the fan gives higher thrust at low speeds. The lower exhaust speed also gives much lower jet noise. Thus civil turbofans today have a low exhaust speed (low specific thrust — net thrust divided by airflow) to keep jet noise to a minimum and to improve fuel efficiency. Consequently, the bypass ratio (bypass flow divided by core flow) is relatively high (ratios from 4:1 up to 8:1 are common), with the Rolls-Royce Trent XWB approaching 10:1. Only a single fan stage is required, because a low specific thrust implies a low fan pressure ratio. Military turbofans, however, have a relatively high specific thrust, to maximize the thrust for a given frontal area, jet noise being of less concern in military uses relative to civil uses. Multistage fans are normally needed to reach the relatively high fan pressure ratio needed for high specific thrust. Although high turbine inlet temperatures are often employed, the bypass ratio tends to be low, usually significantly less than 2.0. Major components of a turbojet including references to turbofans, turboprops and turboshafts: - Air intake (Inlet) — For subsonic aircraft, the inlet is a duct which is required to ensure smooth airflow into the engine despite air approaching the inlet from directions other than straight ahead. This occurs on the ground from cross winds and in flight with aircraft pitch and yaw motions. The duct length is minimised to reduce drag and weight. Air enters the compressor at about half the speed of sound so at flight speeds lower than this the flow will accelerate along the inlet and at higher flight speeds it will slow down. Thus the internal profile of the inlet has to accommodate both accelerating and diffusing flow without undue losses. For supersonic aircraft, the inlet has features such as cones and ramps to produce the most efficient series of shockwaves which form when supersonic flow slows down. The air slows down from the flight speed to subsonic velocity through the shockwaves, then to about half the speed of sound at the compressor through the subsonic part of the inlet. The particular system of shockwaves is chosen, with regard to many constraints such as cost and operational needs, to minimise losses which in turn maximises the pressure recovery at the compressor. - Compressor or Fan — The compressor is made up of stages. Each stage consists of rotating blades and stationary stators or vanes. As the air moves through the compressor, its pressure and temperature increase. The power to drive the compressor comes from the turbine (see below), as shaft torque and speed. - Bypass ducts deliver the flow from the fan with minimum losses to the bypass propelling nozzle. Alternatively the fan flow may be mixed with the turbine exhaust before entering a single propelling nozzle. In another arrangement an afterburner may be installed between the mixer and nozzle. - Shaft — The shaft connects the turbine to the compressor, and runs most of the length of the engine. There may be as many as three concentric shafts, rotating at independent speeds, with as many sets of turbines and compressors. Cooling air for the turbines may flow through the shaft from the compressor. - Diffuser section: - The diffuser slows down the compressor delivery air to reduce flow losses in the combustor. Slower air is also required to help stabilize the combustion flame and the higher static pressure improves the combustion efficiency. - Combustor or Combustion Chamber — Fuel is burned continuously after initially being ignited during the engine start. - Turbine — The turbine is a series of bladed discs that act like a windmill, extracting energy from the hot gases leaving the combustor. Some of this energy is used to drive the compressor. Turboprop, turboshaft and turbofan engines have additional turbine stages to drive a propeller, bypass fan or helicopter rotor. In a free turbine the turbine driving the compressor rotates independently of that which powers the propellor or helicopter rotor. Cooling air, bled from the compressor, may be used to cool the turbine blades, vanes and discs to allow higher turbine entry gas temperatures for the same turbine material temperatures.** - Afterburner or reheat (British) — (mainly military) Produces extra thrust by burning fuel in the jetpipe. This reheating of the turbine exhaust gas raises the propelling nozzle entry temperature and exhaust velocity. The nozzle area is increased to accommodate the higher specific volume of the exhaust gas. This maintains the same airflow through the engine to ensure no change in its operating characteristics. - Exhaust or Nozzle — Turbine exhaust gases pass through the propelling nozzle to produce a high velocity jet. The nozzle is usually convergent with a fixed flow area. - Supersonic nozzle — For high nozzle pressure ratios (Nozzle Entry Pressure/Ambient Pressure) a convergent-divergent (de Laval) nozzle is used. The expansion to atmospheric pressure and supersonic gas velocity continues downstream of the throat and produces more thrust. The various components named above have constraints on how they are put together to generate the most efficiency or performance. The performance and efficiency of an engine can never be taken in isolation; for example fuel/distance efficiency of a supersonic jet engine maximises at about mach 2, whereas the drag for the vehicle carrying it is increasing as a square law and has much extra drag in the transonic region. The highest fuel efficiency for the overall vehicle is thus typically at Mach ~0.85. For the engine optimisation for its intended use, important here is air intake design, overall size, number of compressor stages (sets of blades), fuel type, number of exhaust stages, metallurgy of components, amount of bypass air used, where the bypass air is introduced, and many other factors. For instance, let us consider design of the air intake. The thermodynamics of a typical air-breathing jet engine are modeled approximately by a Brayton Cycle which is a thermodynamic cycle that describes the workings of the gas turbine engine, which is the basis of the airbreathing jet engine and others. It is named after George Brayton (1830–1892), the American engineer who developed it, although it was originally proposed and patented by Englishman John Barber in 1791. It is also sometimes known as the Joule cycle. The nominal net thrust quoted for a jet engine usually refers to the Sea Level Static (SLS) condition, either for the International Standard Atmosphere (ISA) or a hot day condition (e.g. ISA+10 °C). As an example, the GE90-76B has a take-off static thrust of 76,000 lbf (360 kN) at SLS, ISA+15 °C. Naturally, net thrust will decrease with altitude, because of the lower air density. There is also, however, a flight speed effect. Initially as the aircraft gains speed down the runway, there will be little increase in nozzle pressure and temperature, because the ram rise in the intake is very small. There will also be little change in mass flow. Consequently, nozzle gross thrust initially only increases marginally with flight speed. However, being an air breathing engine (unlike a conventional rocket) there is a penalty for taking on-board air from the atmosphere. This is known as ram drag. Although the penalty is zero at static conditions, it rapidly increases with flight speed causing the net thrust to be eroded. As flight speed builds up after take-off, the ram rise in the intake starts to have a significant effect upon nozzle pressure/temperature and intake airflow, causing nozzle gross thrust to climb more rapidly. This term now starts to offset the still increasing ram drag, eventually causing net thrust to start to increase. In some engines, the net thrust at say Mach 1.0, sea level can even be slightly greater than the static thrust. Above Mach 1.0, with a subsonic inlet design, shock losses tend to decrease net thrust, however a suitably designed supersonic inlet can give a lower reduction in intake pressure recovery, allowing net thrust to continue to climb in the supersonic regime. Safety and reliability Jet engines are usually very reliable and have a very good safety record. However, failures do sometimes occur. In some cases in jet engines the conditions in the engine due to airflow entering the engine or other variations can cause the compressor blades to stall. When this occurs the pressure in the engine blows out past the blades, and the stall is maintained until the pressure has decreased, and the engine has lost all thrust. The compressor blades will then usually come out of stall, and re-pressurize the engine. If conditions are not corrected, the cycle will usually repeat. This is called surge. Depending on the engine this can be highly damaging to the engine and creates worrying vibrations for the crew. Fan, compressor or turbine blade failures have to be contained within the engine casing. To do this the engine has to be designed to pass blade containment tests as specified by certification authorities. Bird ingestion is the term used when birds enter the intake of a jet engine. It is a common aircraft safety hazard and has caused fatal accidents. In 1988 an Ethiopian Airlines Boeing 737 ingested pigeons into both engines during take-off and then crashed in an attempt to return to the Bahir Dar airport; of the 104 people aboard, 35 died and 21 were injured. In another incident in 1995, a Dassault Falcon 20 crashed at a Paris airport during an emergency landing attempt after ingesting lapwings into an engine, which caused an engine failure and a fire in the airplane fuselage; all 10 people on board were killed. In 2009, an Airbus A320 aircraft, US Airways Flight 1549, ingested one bird into each engine. The plane ditched in the Hudson River after taking off from LaGuardia International Airport in New York City. There were no fatalities. Jet engines have to be designed to withstand the ingestion of birds of a specified weight and number and to not lose more than a specified amount of thrust. The weight and numbers of birds that can be ingested without hazarding the safe flight of the aircraft are related to the engine intake area. The hazards of ingesting birds beyond the "designed-for" limit were shown on US Airways Flight 1549 when the aircraft struck Canada geese. The outcome of an ingestion event and whether it causes an accident, be it on a small fast plane, such as military jet fighters, or a large transport, depends on the number and weight of birds and where they strike the fan blade span or the nose cone. Core damage usually results with impacts near the blade root or on the nose cone. The highest risk of a bird ingestion is during takeoff and landing and during low level flying. If a jet plane is flying through air contaminated with volcanic ash, there is risk that ingested ash will cause erosion damage to the compressor blades, blockage of fuel nozzle air holes and blockage of the turbine cooling passages. Some of these effects may cause the engine to surge or flame-out during the flight. Re-lights are usually successful after flame-outs but with considerable loss of altitude. It was the case of British Airways Flight 9 which flew through volcanic dust at 37,000 ft. All 4 engines flamed out and re-light attempts were successful at about 13,000 ft. One class of failure that has caused accidents is the uncontained failure, where rotating parts of the engine break off and exit through the case. These high energy parts can cut fuel and control lines, and can penetrate the cabin. Although fuel and control lines are usually duplicated for reliability, the crash of United Airlines Flight 232 was caused when hydraulic fluid lines for all three independent hydraulic systems were simultaneously severed by shrapnel from an uncontained engine failure. Prior to the United 232 crash, the probability of a simultaneous failure of all three hydraulic systems was considered as high as a billion-to-one. However, the statistical models used to come up with this figure did not account for the fact that the number-two engine was mounted at the tail close to all the hydraulic lines, nor the possibility that an engine failure would release many fragments in many directions. Since then, more modern aircraft engine designs have focused on keeping shrapnel from penetrating the cowling or ductwork, and have increasingly utilized high-strength composite materials to achieve the required penetration resistance while keeping the weight low. Jet engines are usually run on fossil fuels and are thus a source of carbon dioxide in the atmosphere. Jet engines can also run on biofuels or hydrogen, although hydrogen is usually produced from fossil fuels. About 7.2% of the oil used in 2004 was consumed by jet engines. Nitrogen compounds are also formed during the combustion process from reactions with atmospheric nitrogen. At low altitudes this is not thought to be especially harmful, but for supersonic aircraft that fly in the stratosphere some destruction of ozone may occur. Sulphates are also emitted if the fuel contains sulphur. A ramjet is a form of airbreathing jet engine using the engine's forward motion to compress incoming air, without a rotary compressor. Ramjets cannot produce thrust at zero airspeed and thus cannot move an aircraft from a standstill. Ramjets require considerable forward speed to operate well, and as a class work most efficiently at speeds around Mach 3. This type of jet can operate up to speeds of Mach 6. Ramjets can be particularly useful in applications requiring a small and simple engine for high speed use, such as missiles, while weapon designers are looking to use ramjet technology in artillery shells to give added range: it is anticipated that a 120-mm mortar shell, if assisted by a ramjet, could attain a range of 22 mi (35 km). They have also been used successfully, though not efficiently, as tip jets on helicopter rotors. Ramjets are frequently confused with pulsejets, which use an intermittent combustion, but ramjets employ a continuous combustion process, and are a quite distinct type of jet engine. P&W J58 Mach 3+ afterburning turbojet Turbojet operation over the complete flight envelope from zero to Mach 3+ requires features to allow the compressor to function properly at the high inlet temperatures beyond Mach 2.5 as well as at low flight speeds. The J58 compressor solution was to bleed airflow from the 4th compressor stage at speeds above about Mach 2. The bleed flow, 20% at Mach 3, was returned to the engine via 6 external tubes to cool the afterburner liner and primary nozzle as well as to provide extra air for combustion. The J58 engine was the only operational turbojet engine, being designed to operate continuously even at maximum afterburning, for Mach 3.2 cruise. An alternative solution is seen in a contemporary installation, which did not reach operational status, the Mach 3 GE YJ93/XB-70. It used a variable stator compressor. Yet another solution was specified in a proposal for a Mach 3 reconnaissance Phantom. This was pre-compressor cooling, albeit available for relatively short duration. Hydrogen-fuelled air-breathing jet engines Jet engines can be run on almost any fuel. Hydrogen is a highly desirable fuel, as, although the energy per mole is not unusually high, the molecule is very much lighter than other molecules. The energy per kg of hydrogen is twice that of more common fuels and this gives twice the specific impulse. In addition, jet engines running on hydrogen are quite easy to build—the first ever turbojet was run on hydrogen. Also, although not duct engines, hydrogen-fueled rocket engines have seen extensive use. However, in almost every other way, hydrogen is problematic. The downside of hydrogen is its density; in gaseous form the tanks are impractical for flight, but even in the form of liquid hydrogen it has a density one fourteenth that of water. It is also deeply cryogenic and requires very significant insulation that precludes it being stored in wings. The overall vehicle would end up being very large, and difficult for most airports to accommodate. Finally, pure hydrogen is not found in nature, and must be manufactured either via steam reforming or expensive electrolysis. Nevertheless, research is ongoing and hydrogen-fueled aircraft designs do exist that may be feasible. Precooled jet engines An idea originated by Robert P. Carmichael in 1955 is that hydrogen-fueled engines could theoretically have much higher performance than hydrocarbon-fueled engines if a heat exchanger were used to cool the incoming air. The low temperature allows lighter materials to be used, a higher mass-flow through the engines, and permits combustors to inject more fuel without overheating the engine. This idea leads to plausible designs like Reaction Engines SABRE, that might permit single-stage-to-orbit launch vehicles, and ATREX, which could permit jet engines to be used up to hypersonic speeds and high altitudes for boosters for launch vehicles. The idea is also being researched by the EU for a concept to achieve non-stop antipodal supersonic passenger travel at Mach 5 (Reaction Engines A2). Project Pluto was a nuclear-powered ramjet, intended for use in a cruise missile. Rather than combusting fuel as in regular jet engines, air was heated using a high-temperature, unshielded nuclear reactor. This dramatically increased the engine burn time, and the ramjet was predicted to be able to cover any required distance at supersonic speeds (Mach 3 at tree-top height). However, there was no obvious way to stop it once it had taken off, which is a great disadvantage in any non-disposable application. Also, because the reactor was unshielded, it was dangerous to be in or around the flight path of the vehicle (although the exhaust itself wasn't radioactive), and the project was cancelled. Scramjets are an evolution of ramjets that are able to operate at much higher speeds than any other kind of airbreathing engine. They share a similar structure with ramjets, being a specially shaped tube that compresses air with no moving parts through ram-air compression. Scramjets, however, operate with supersonic airflow through the entire engine. Thus, scramjets do not have the diffuser required by ramjets to slow the incoming airflow to subsonic speeds. Scramjets start working at speeds of at least Mach 4, and have a maximum useful speed of approximately Mach 17. Due to aerodynamic heating at these high speeds, cooling poses a challenge to engineers. The air turborocket is a form of combined-cycle jet engine. The basic layout includes a gas generator, which produces high pressure gas, that drives a turbine/compressor assembly which compresses atmospheric air into a combustion chamber. This mixture is then combusted before leaving the device through a nozzle and creating thrust. There are many different types of air turborockets. The various types generally differ in how the gas generator section of the engine functions. Air turborockets are often referred to as turboramjets, turboramjet rockets, turborocket expanders, and many others. As there is no consensus on which names apply to which specific concepts, various sources may use the same name for two different concepts. This section does not cite any sources. (July 2010) (Learn how and when to remove this template message) To specify the RPM, or rotor speeds, of a jet engine, abbreviations are commonly used: - For a turboprop engine, Np refers to the RPM of the propeller shaft. For example, a common Np would be about 2200 RPM for a constant speed propeller. - N1 or Ng refers to the RPM of the gas generator section. Each engine manufacturer will pick between those two abbreviation. N1 is also used for the fan speed on a turbofan, in which case N2 is the gas generator speed (2 shaft engine). Ng is mainly used for turboprop or turboshaft engines. For example, a common Ng would be on the order of 30,000 RPM. - N2 or Nf refers to the speed of the power turbine section. Each engine manufacturer will pick between those two abbreviations but N2 is mainly used for turbofan engines whereas Nf is mainly used for turboprop or turboshaft engines. In many cases, even for free turbine engines, the N1 and N2 may be very similar. - Ns refers to the speed of the reduction gear box (RGB) output shaft for turboshaft engines. In many cases, instead of expressing rotor speeds (N1, N2) as RPM on cockpit displays, pilots are provided with the speeds expressed as a percentage of the design point speed. For example, at full power, the N1 might be 101.5% or 100%. This user interface decision has been made as a human factors consideration, since pilots are more likely to notice a problem with a two- or 3-digit percentage (where 100% implies a nominal value) than with a 5-digit RPM. - Rocket engine - Turboprop – a gas turbine engine used to turn propellers - Turboshaft – a gas turbine engine used for helicopters - "Gas Turbine Technology Evolution: A Designer's Perspective" Bernard L.Koff Journal of Propulsion and Power Vol20 No4 July–August 2004 Fig.34/41 - Angelo, Joseph A. (2004). The Facts on File dictionary of space technology (3 ed.). Infobase Publishing. p. 14. ISBN 0-8160-5222-0. - "Turbojet Engine". NASA Glenn Research Center. Archived from the original on 8 May 2009. Retrieved 2009-05-06. - "Trent XWB infographic". Retrieved 2015-10-15. - "Trade-offs in jet inlet design" Andras Sobester Journal of Aircraft, Vol44 No3 May–June 2007 - "Jet Propulsion for Aerospace Applications" 2nd edition, Walter J.hesse Nicholas V.S. MumfordPitman Publishing Corp 1964 p110 - "Jet Propulsion for Aerospace Applications" 2nd edition, Walter J.hesse Nicholas V.S. MumfordPitman Publishing Corp 1964 p216 - according to Gas Turbine History Archived 3 June 2010 at the Wayback Machine. - "Part33 Airworthiness Standards- Aircraft Engines" para 33.94 Blade containment and rotor out of balance tests - "Transport Canada - Sharing the Skies". Tc.gc.ca. 2010-01-06. Archived from the original on 17 March 2010. Retrieved 2010-03-26. - "Part33-Airworthiness Standards-Aircraft Engines section 33.76 Bird ingestion - flightglobal archive Flight International 10 July 1982 p59 - U.S. Airlines: Operating in an Era of High Jet Fuel Prices - "How many air-miles are left in the world's fuel tank?". After-oil.co.uk. 2005-06-29. Archived from the original on 17 March 2010. Retrieved 2010-03-26. - McNab, Chris; Hunter Keeter (2008). Tools of Violence: Guns, Tanks and Dirty Bombs. Osprey Publishing. p. 145. ISBN 1-84603-225-3. - "Here Comes the Flying Stovepipe". TIME. 26 November 1965. Archived from the original on 9 March 2008. Retrieved 2008-03-09. - U.S.Patent 3,344,606 "Recover Bleed Air Turbojet" Robert B. Abernethy - sr-71.org Blackbird Manual Section 1 Description and Operation page 1-20 - enginehistory.org Presentation by Pete Law "SR-71 Propulsion, Part 2" - "Jet Propulsion for Aerospace Applications- second edition" Walter J. Hesse, Nicholas V.S. Mumford,Jr. Pitman Publishing corporation. p377 - aviationtrivia.blogspot.ca "Tails Through Time" J P Santiago Wednesday,July 18, 2012 "The Mach 3 Phantom" - "F-12 Series Aircraft Propulsion System Performance and Development"David H. Campbell, J.AircraftVol 11, No 11, November 1974 - e.g. Reaction engines A2 hypersonic airliner - "NASA history Other Interests in Hydrogen". Hq.nasa.gov. 1955-10-21. Retrieved 2010-03-26. - "The Skylon Spaceplane" (PDF). Archived from the original (PDF) on 15 June 2011. Retrieved 2010-03-26. - "Astronautix X30". Astronautix.com. Retrieved 2010-03-26. - Heiser and Pratt, p. 457 - PRATT & WHITNEY CANADA MAINTENANCE MANUAL - MANUAL PART NO. 3017042 - Introduction - Page 6 - Email from subject matter expert - Sr. Field Support Representative, Pratt & Whitney Canada Worldwide Support Network 12 Jan 2010
Rice University physicists have created a tiny "electron superhighway" that could one day be useful for building a quantum computer, a new type of computer that will use quantum particles in place of the digital transistors found in today's microchips. In a recent paper in Physical Review Letters, Rice physicists Rui-Rui Du and Ivan Knez describe a new method for making a tiny device called a "quantum spin Hall topological insulator." The device, which acts as an electron superhighway, is one of the building blocks needed to create quantum particles that store and manipulate data. Today's computers use binary bits of data that are either ones or zeros. Quantum computers would use quantum bits, or "qubits," which can be both ones and zeros at the same time, thanks to the quirks of quantum mechanics. This quirk gives quantum computers a huge edge in performing particular types of calculations, said Du, professor of physics and astronomy at Rice. For example, intense computing tasks like code-breaking, climate modeling and biomedical simulation could be completed thousands of times faster with quantum computers. "In principle, we don't need many qubits to create a powerful computer," he said. "In terms of information density, a silicon microprocessor with 1 billion transistors would be roughly equal to a quantum processor with 30 qubits."In the race to build quantum computers, researchers are taking a number of approaches to creating qubits. Regardless of the approach, a common problem is making certain that information encoded into qubits isn't lost over time due to quantum fluctuations. This is known as "fault tolerance." The elusive Majorana fermions were first proposed in 1937, although the race to create them in a chip has just begun. In particular, physicists believe the particles can be made by marrying a two-dimensional topological insulator -- like the one created by Du and Knez -- to a superconductor. Topological insulators are oddities; although electricity cannot flow through them, it can flow around their narrow outer edges. If a small square of a topological insulator is attached to a superconductor, Knez said, the elusive Majorana fermions are expected to appear precisely where the materials meet. If this proves true, the devices could potentially be used to generate qubits for quantum computing, he said. Knez spent more than a year refining the techniques to create Rice's topological insulator. The device is made from a commercial-grade semiconductor that's commonly used in making night-vision goggles. Du said it is the first 2-D topological insulator made from a material that physicists already know how to attach to a superconductor. "We are well-positioned for the next step," Du said. "Meanwhile, only experiments can tell whether we can find Majorana fermions and whether they are good candidates for creating stable qubits." The research was funded by the National Science Foundation, Rice University, the Hackerman Advanced Research Program, the Welch Foundation and the Keck Foundation. A copy of the PRL paper is available at: http://prl.aps.org/abstract/PRL/v107/i13/e136603 Jade Boyd \| EurekAlert! The taming of the light screw 22.03.2019 \| Max-Planck-Institut für Struktur und Dynamik der Materie 21.03.2019 \| Max-Planck-Institut für Polymerforschung Cancers that display a specific combination of sugars, called T-antigen, are more likely to spread through the body and kill a patient. However, what regulates... DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials. The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a... Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains. The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also... Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again. Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are... The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi. A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes... 11.03.2019 \| Event News 01.03.2019 \| Event News 28.02.2019 \| Event News 26.03.2019 \| Trade Fair News 26.03.2019 \| Life Sciences 25.03.2019 \| Trade Fair News
Inside a computer all information is stored as binary numbers – either a 1 or a 0. In a computer this will mean either a switch being open or closed, or the presence or absence of a voltage signal travelling down a wire. Every single type of data – sound, graphics, text, animations, etc. will always be stored as a series of binary numbers. Each of these numbers has a size, the bigger the size, the bigger the data. In this lesson, we’ll learn about: - The different units of data storage. - How to convert between the different units of data storage. - Why data needs to be converted to binary in order to be processed. 1. The Units of Data Storage The smallest unit of data inside a computer is called a bit. This represents either a 1 or a 0. It corresponds to a micro switch inside the CPU or RAM or an SSD drive. This is shown in figure 1 – here if the switch is OPEN, it means a 0, if it is CLOSED, it means a 1. All this means is that if it is closed, electricity can flow through the switch. Inside the computer there are millions of switches that are constantly opening and closing, as they store different numbers, or do different calculations. The wires on the motherboard that move data around will either have a voltage (1) or will not (0) and this is how data is moved from the hard drive to RAM and to the CPU. If a piece of data can only be a 1 or a 0, then it is called BINARY data. Computers usually store data using much larger values than individual bits though, so there are other units of measurement we can use when referring to these larger values. A group of 8 bits is called a byte. A group of 4 bits is called a nibble (because a nibble is a small byte – say it out loud to yourself!). We usually deal with groups of bytes, rather than individual bits. The table below shows the different unit names that you need to be familiar with. You will have seen these numbers relating to processor speed – a 2.3 Gigahertz processor will carry out 2.3 billion operations per second. The table below shows us the units being applied to memory capacity. \|Unit Name\|\|No. of Bytes\|\|Meaning\| \|Kilobyte\|\|103\|\|1 Thousand Bytes\| \|Megabyte\|\|106\|\|1 Million Bytes\| \|Gigabyte\|\|109\|\|1 Billion Bytes\| \|Terabyte\|\|1012\|\|1 Thousand Billion Bytes\| \|Petabyte\|\|1015\|\|1 Million Billion Bytes\| You will have seen these numbers when buying your phone, which might have a 128 Gigabyte flash drive, or a new computer might have a 1 Terabyte hard disk drive. Research the typical storage capacity for a computer built in 2010. Look at how much storage capacity has increased since then. 2. Converting Between Units The way to convert numbers is shown in figure 2. Basically, if you are going from big numbers to small numbers, you need to multiply. If you are going from small numbers to big numbers, you need to divide. Let’s look at some worked examples: Worked Example 1 How many bytes are in 3 Kilobytes? So looking at the table below, we have to do 1 multiplication jump: So 3 Kilobytes = 3000 bytes. Worked Example 2 How many bytes are in 5 Megabytes? Again, looking at the table below, we have to do 2 multiplication jumps: So 5 Megabytes = 5,000,000 bytes (5 million bytes). Worked Example 3 How many Kilobytes in 6500 bytes? This time we need to divide, so looking at the table below, have to do 1 division jump: So 6500 bytes = 6.5 Kilobytes. Buying computers now with Terabyte hard drives is common. Research what is the largest available hard drive, and what is the largest hard drive currently in use in the world. 3. Why Data is Converted to Binary When you type a letter on your keyboard – have you thought about what is going on? An electrical signal goes from your keyboard to your CPU. That signal will turn some switches on and off, and the operating system and CPU recognise these instructions and use this to print out the letter you have typed on the screen. All of the registers inside the CPU basically consist of millions of tiny switches. There is also a part of the CPU called the ALU – the Arithmetic Logic Unit, whose job it is to perform any calculation that has to be carried out – any addition or subtraction. However, all of these numbers can only be stored and processed as switches that are either open or closed, and so are a 1 or a 0. The CPU has no idea what a decimal number is, or a photo, or an MP3, or a game. All it knows about is that some switches have to be open, and some need to be closed. In this way, all data in your computer needs to be converted into binary in order for it to be processed. Can you think of any data that might not be stored as binary data inside a computer? ADVANCED THOUGHT: Binary data is thought of as existing as a binary state 1 or 0, but quantum computing can exist in multiple states at once. How? So to summarise what we’ve learnt in this lesson: - All data exists in a computer as binary data – a 1 or a 0. - This corresponds to a switch being open (0), or closed (1). - The smallest unit of data is a bit which is either 1 or 0. - We often group bits together into larger units of data, such as: - A nibble is 4 bits. - A byte is 8 bits. - A Kilobyte is a thousand bytes. - A Megabyte is a thousand Kilobytes. - A Gigabyte is a thousand Megabytes. - A Terabyte is a thousand Gigabytes. - A Petabyte is a thousand Terabytes. - To convert between units, you need to multiply when going from large to small, and divide when going from small to large.
2nd grade math problems 2nd grade math problems second grade is the time for 7 – 8-year-olds to review what they have learnt in first grade and strengthen their foundation in the subject check out our collection of second grade math problems to give the little ones some math practice. Skills available for common core second-grade math standards standards are in black and ixl math skills are in dark green hold your mouse over the name of a skill to view a sample question click on the name of a skill to practice that skill 2oaa represent and solve problems involving addition and subtraction. 2nd grade games, videos and worksheets in second grade math, children move from counting, adding, and subtracting double- and triple-digit numbers to recognizing fractions and using numbers into the thousands. Doctor-geniuscom: 2nd grade: addition who says learning is not all fun and games unlimited math practice. Second grade math here is a list of all of the math skills students learn in second grade these skills are organized into categories, and you can move your mouse over any skill name to preview the skill. Grade 1 grade 2 grade 3 grade 4 grade 5 grade 6 math playground for teachers a collection of math word problems for grades 1 to 6 advertisement \| go ad-free addition i - one step word problem set 1 word problem set 2 word problem set 3 word problem set 4 word problem set 5 word problem set 6. Second grade math fourth grade math 2nd grade math games grade 2 guided math math 2 math worksheets math activities math resources forward math word problemscheck out this freebie and start a new tradition in your classroom. Spelling grade 2 spelling grade 3 spelling grade 4 spelling grade 5 more spelling worksheets challenge your students to solve these tricky multi-step math problems each one requires students to add and/or subtract 2nd and 3rd grades here are four multiple-step word problems that will require a combination of addition. Addition for 2nd grade built on prior knowledge this 2nd grade addition worksheets stack raises the level gradually enclosed here are 2 and 3-digit addition drills involving regrouping, addition of base 10 blocks, real-life word problems and more. The ck-12 foundation is a leading non-profit organization dedicated to increasing access to high-quality k-12 stem open educational resources (oer. 2nd grade these tasks are grade-level formative performance assessment tasks aligned to the common core state standards for mathematics some have accompanying scoring rubrics and discussion of student work samples. This educational activity provides word problems with manipulatives for kids to practice adding and subtracting within 20 the word problems are read aloud and have objects that can be used for counting. Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more khan academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere. This math worksheet presents word problems for your child to solve using mental math, addition, and subtraction. Free math worksheets for grade 2 this is a comprehensive collection of free printable math worksheets for grade 2, organized by topics such as addition, subtraction, mental math, regrouping, place value, clock, money, geometry, and multiplication. 2nd grade math problems Grade five kidzone math math word problems introduction: the word problems are listed by grade and, within each grade, by theme i always find that providing a seasonal worksheet helps keep my daughter excited about doing her work the grade levels are a guideline -- please use your judgment based on your child's ability and eagerness (my. Kids in 1st and 2nd grade will learn about double digit addition with regrouping in this fun worksheet video we have the worksheet for free download on our website and the kids can follow along. Welcome to our common core printables section for 2nd grade math look for a rapidly growing variety of thousands of online practice sets tied to the common core state standards. End of year test - grade 2 basic addition and subtraction facts in problems 1 and 2, your teacher will read you the addition and subtraction questions. 2nd grade: word problems home / 2nd grade: created by the 2nd grade math leadership team read more 2nd grade word problem rubric recording sheets small recording slips to attach to word problems read more 2nd grade word problem rubric read more 2nd grade word problem strategy monitoring recording sheet. Word problems can be challenging for students, especially second-graders, who may still be learning to readbut, you can use basic strategies that will work with nearly any student, even those who are just starting to learn written-language skills. The 2nd grade math worksheets in this section include the core addition, subtraction, multiplication and (if they're ready) division fact practice additional topics for 2nd grade include writing numbers in expanded form, measurement, rounding and telling analog time. Second grade math worksheets and printables whether your child needs a challenge or a little extra help with a specific second grade math skill, our second grade math worksheets are here to help get practice and support for skills like rounding, word problems, measurement and more. Free grade 2 math worksheets for mastering some basic math skills, there is nothing more effective than practicing solving problems with a pencil and paper our grade 2 math worksheets complement our online math program. 2nd grade online math: it is all here, in total alignment with school practice makes perfect including videos and results.
Researchers simulated conditions that occur when a piece of the planet is ejected into space, and their findings could alter assumptions about the water budget of Mars. In a twist for Martian meteorite studies, it turns out their mineral composition may show that the Red Planet was wet and possibly habitable in the past. It’s the opposite of what researchers thought based on past examinations of meteorites, which hinted at a dry and dusty history. The findings come from studying a synthetic version of whitlockite, a rare mineral on Earth. The research team ran shock-compression experiments to simulate the conditions that happen when a Martian sample is ejected from Mars into space; a fraction of these meteorites then make their way to Earth, where they fall on the surface and are collected. Scientists studied the sample using X-ray experiments at Berkeley Lab‘s Advanced Light Source and at Argonne National Laboratory‘s Advanced Photon Source. Results show that the whitlockite becomes dehydrated and creates a mineral called merrillite, which has been found many times in Martian meteorites. “If even a part of merrillite had been whitlockite before, it changes the water budget of Mars dramatically,” Oliver Tschauner, co-leader of the study and a research professor in the Department of Geoscience at the University of Nevada, Las Vegas, said in a statement. If the study proves true of actual Martian meteorites, this would help resolve a discrepancy between meteorite studies and examinations on the planet itself. While meteorite studies showed that Mars was dry, examinations by Martian rovers show abundant evidence of water. Certain minerals (such as hematite) formed in the presence of water. The Curiosity rover has also seen rounded pebbles and other evidence of ancient streambeds. From orbit, pictures have shown ancient gullies that were likely worn down by water flow, although other explanations, such as lava, have been proposed as well. In 2015, NASA announced, based on examinations by the Mars Reconnaissance Orbiter, that briny water may even flow today. Features called recurring slope lineae on Mars, which tend to appear in warmer weather, appear consistent with water flow. Whitlockite contains phosphorous — a needed element for life on Earth — and can also dissolve in water. Since merrillite is found in so many Martian meteorites, the study suggests that habitable conditions for life on Mars were common, at least in the region from where the meteorites came. “The only missing link now is to prove that (merrillite) had, in fact, really been Martian whitlockite before,” Tschauner said. “We have to go back to the real meteorites and see if there had been traces of water.” A key limitation of the study is the origins of Martian meteorites. Many collected on Earth likely came from one region of Mars, and only during a narrow time period: 150-586 million years ago. These meteorites represent samples below the surface that were excavated when an impact on Mars sent them flying off the planet. Because these samples were buried, they are believed to indicate the Martian environment in the more ancient past. The researchers plan follow-up studies with actual Martian meteorite samples later this year. Independent studies are ongoing to learn more about the past habitability of Mars. NASA plans to send another rover there in 2020 to collect samples and possibly cache them for a future sample-return mission. Such a sample could then be examined on Earth with sophisticated laboratory instruments that are impossible to send to Mars due to their size, among other factors. Latest posts by Sebastien Clarke (see all) - SpaceX preparing to begin Starship hopper tests - March 18, 2019 - Moon dust kept sealed for 50 years will finally reveal its secrets - March 17, 2019 - NASA Television to Air Three Upcoming Spacewalks, Preview Briefing - March 16, 2019
In Aristotelian logic a syllogism is an argument consisting of three propositions. The last is called the conclusion, which is a necessary consequence of the two preceding, which are called premisses. The conclusion has two terms, a subject and a predicate. The predicate is called the major term, its subject the minor term. To entail the conclusion, each of its terms must be compared in the premises with a third term, the middle term. Thus one premise has the major term and the middle term, and is called the major premise. The other has the minor term and the middle term, and is called the minor premise. Structure of the syllogism Thus the syllogism consists of three propositions: the major, the minor, and the conclusion. and though each has two terms, a subject and a predicate, there are only three different terms in all. The major term is always the predicate of the conclusion, and so is either the subject or predicate of the major premiss. The minor term is always the subject of the conclusion, and is either the subject or predicate of the minor premise. The middle term is never in the conclusion, but is in both premises, either as subject or predicate. The figure of the syllogism depends on the the positions which the Middle Term may have in the premises. There are on four possible positions. It may be the subject of the major premise, and the predicate of the minor, and then the syllogism is of the first figure; or it may be the predicate of both premises, and then the syllogism is of the second figure; or it may be the subject of both, which makes a syllogism of the third figure; or it may be the predicate of the major premise, and the subject of the minor, which makes the fourth figure. Another division of syllogisms is by mode. The mode is determined by the Quality and Quantity of the propositions. Any propositions must be either a universal affirmative, or a universal negative, or a particular affirmative, or a particular negative. These four kinds of propositions, were named by the four vowels A, E, I, O. Thus, AAA is the mode in which the major, minor and conclusion, are all universal affirmatives. EAE is the mode in which the major and conclusion are universal negatives and the minor is an universal affirmative. And so on. - ^ Aristotle does not discuss the fourth figure. It was added by Galen, and was sometimes called the Galenical Figure
American Revolutionary War The American Revolutionary War, also known as the Revolutionary War or the American War of Independence, was initiated by delegates from thirteen American colonies of British America in Congress against Great Britain over their objection to Parliament's taxation policies and lack of colonial representation. Table of Contents / Timeline PrologueBoston, MA, USA The 1763 to 1765 Grenville ministry instructed the Royal Navy to stop the trade of smuggled goods and enforce customs duties levied in American ports. The most important was the 1733 Molasses Act; routinely ignored prior to 1763, it had a significant economic impact since 85% of New England rum exports were manufactured from imported molasses. These measures were followed by the Sugar Act and Stamp Act, which imposed additional taxes on the colonies to pay for defending the western frontier. Tensions escalated following the destruction of a customs vessel in the June 1772 Gaspee Affair, then came to a head in 1773. A banking crisis led to the near-collapse of the East India Company, which dominated the British economy; to support it, Parliament passed the Tea Act, giving it a trading monopoly in the Thirteen Colonies. Since most American tea was smuggled by the Dutch, the Act was opposed by those who managed the illegal trade, while being seen as yet another attempt to impose the principle of taxation by Parliament. Stamp ActBoston, MA, USA The Stamp Act of 1765 was an Act of the Parliament of Great Britain which imposed a direct tax on the British colonies in America and required that many printed materials in the colonies be produced on stamped paper produced in London, carrying an embossed revenue stamp. Quartering ActNew York General Thomas Gage, commander-in-chief of forces in British North America, and other British officers who had fought in the French and Indian War (including Major James Robertson), had found it hard to persuade colonial assemblies to pay for quartering and provisioning of troops on the march. Therefore, he asked Parliament to do something. Most colonies had supplied provisions during the war, but the issue was disputed in peacetime. This first Quartering Act was given Royal Assent on May 15, 1765, and provided that Great Britain would house its soldiers in American barracks and public houses, as by the Mutiny Act 1765, but if its soldiers outnumbered the housing available, would quarter them in "inns, livery stables, ale houses, victualing houses, and the houses of sellers of wine and houses of persons selling of rum, brandy, strong water, cider or metheglin", and if numbers required in "uninhabited houses, outhouses, barns, or other buildings." Colonial authorities were required to pay the cost of housing and feeding these soldiers. Townshend ActsNew York, USA The Townshend Acts or Townshend Duties, refers to a series of British acts of Parliament passed during 1767 and 1768 relating to the British colonies in America. They are named after Charles Townshend, the Chancellor of the Exchequer who proposed the program. The Boston Massacre was a confrontation on March 5, 1770, in which British soldiers shot and killed several people while being harassed by a mob in Boston. The event was heavily publicized by leading Patriots such as Paul Revere and Samuel Adams. Boston Tea PartyBoston, MA The Boston Tea Party was an American political and mercantile protest by the Sons of Liberty in Boston, Massachusetts, on December 16, 1773. The target was the Tea Act of May 10, 1773, which allowed the British East India Company to sell tea from China in American colonies without paying taxes apart from those imposed by the Townshend Acts. The Sons of Liberty strongly opposed the taxes in the Townshend Act as a violation of their rights. Protesters, some disguised as American Indians, destroyed an entire shipment of tea sent by the East India Company. Intolerable ActsLondon, UK The Intolerable Acts were punitive laws passed by the British Parliament in 1774 after the Boston Tea Party. The laws were meant to punish the Massachusetts colonists for their defiance in the Tea Party protest in reaction to changes in taxation by the British Government. First Continental CongressCarpenter's Hall, Philadelphia The First Continental Congress was a meeting of delegates from 12 of the 13 British colonies that became the United States. It met from September 5 to October 26, 1774, at Carpenters' Hall in Philadelphia, Pennsylvania, after the British Navy instituted a blockade of Boston Harbor and Parliament passed the punitive Intolerable Acts in response to the December 1773 Boston Tea Party. During the opening weeks of the Congress, the delegates conducted a spirited discussion about how the colonies could collectively respond to the British government's coercive actions, and they worked to make a common cause. Battles of Lexington and ConcordMiddlesex County, Massachusett The battles of Lexington and Concord were the first military engagements of the American Revolutionary War. The battles were fought on April 19, 1775 in Middlesex County, Province of Massachusetts Bay, within the towns of Lexington, Concord, Lincoln, Menotomy, and Cambridge. Capture of Fort TiconderogaTiconderoga, New York Continental Army formedNew England Battle of Bunker HillCharlestown, Boston The Battle of Bunker Hill was fought on June 17, 1775, during the Siege of Boston in the first stage of the American Revolutionary War. The battle is named after Bunker Hill in Charlestown, Massachusetts, which was peripherally involved in the battle. It was the original objective of both the colonial and British troops, though the majority of combat took place on the adjacent hill which later became known as Breed's Hill. Battle of QuebecQuébec, QC, Canada The Battle of Quebec (French: Bataille de Québec) was fought on December 31, 1775, between American Continental Army forces and the British defenders of Quebec City early in the American Revolutionary War. The battle was the first major defeat of the war for the Americans, and it came with heavy losses. General Richard Montgomery was killed, Benedict Arnold was wounded, and Daniel Morgan and more than 400 men were taken prisoner. The city's garrison, a motley assortment of regular troops and militia led by Quebec's provincial governor, General Guy Carleton, suffered a small number of casualties. Common SensePhiladelphia, PA, USA Common Sense is a 47-page pamphlet written by Thomas Paine in 1775–1776 advocating independence from Great Britain to people in the Thirteen Colonies. Writing in clear and persuasive prose, Paine marshaled moral and political arguments to encourage common people in the Colonies to fight for egalitarian government. British evacuate BostonBoston, MA Battle of Sullivan's IslandSullivan's Island, South Carol The Battle of Sullivan's Island or the battle of Fort Sullivan was fought on June 28, 1776, during the American Revolutionary War. It took place near Charleston, South Carolina, during the first British attempt to capture the city from American forces. It is also sometimes referred to as the first siege of Charleston, owing to a more successful British siege in 1780. United States Declaration of IndependencePhiladephia, PA The United States Declaration of Independence is the pronouncement adopted by the Second Continental Congress meeting in Philadelphia, Pennsylvania, on July 4, 1776. The Declaration explained why the Thirteen Colonies at war with the Kingdom of Great Britain regarded themselves as thirteen independent sovereign states, no longer under British rule. With the Declaration, these new states took a collective first step toward forming the United States of America. The declaration was signed by representatives from New Hampshire, Massachusetts Bay, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Maryland, Delaware, Virginia, North Carolina, South Carolina, and Georgia. Battle of Long IslandBrooklyn, NY, USA The Battle of Long Island, also known as the Battle of Brooklyn and the Battle of Brooklyn Heights, was an action of the American Revolutionary War fought on Tuesday, August 27, 1776, at the western edge of Long Island in the present-day Brooklyn, New York. The British defeated the Americans and gained access to the strategically important Port of New York, which they held for the rest of the war. It was the first major battle to take place after the United States declared its independence on July 4, and in troop deployment and combat, it was the largest battle of the war. After defeating the British in the siege of Boston on March 17, commander-in-chief George Washington relocated the Continental Army to defend the port city of New York, located at the southern end of Manhattan Island. Washington understood that the city's harbor would provide an excellent base for the Royal Navy, so he established defenses there and waited for the British to attack. In July, the British, under the command of General William Howe, landed a few miles across the harbor on the sparsely populated Staten Island, where they were reinforced by a fleet of ships in Lower New York Bay over the next month and a half, bringing their total force to 32,000 troops. Washington knew the difficulty in holding the city with the British fleet in control of the entrance to the harbor at the Narrows, and accordingly moved the bulk of his forces to Manhattan, believing that it would be the first target. On August 21, the British landed on the shores of Gravesend Bay in southwest Kings County, across the Narrows from Staten Island and more than a dozen miles south of the established East River crossings to Manhattan. After five days of waiting, the British attacked the American defenses on the Guan Heights. Unknown to the Americans, however, Howe had brought his main army around their rear and attacked their flank soon after. The Americans panicked, resulting in twenty percent losses through casualties and capture, although a stand by 400 Maryland and Delaware troops prevented greater losses. The remainder of the army retreated to the main defenses on Brooklyn Heights. The British dug in for a siege, but on the night of August 29–30, Washington evacuated the entire army to Manhattan without the loss of supplies or a single life. The Continental Army was driven out of New York entirely after several more defeats and was forced to retreat through New Jersey to Pennsylvania. Battle of Fort WashingtonWashington Heights, Manhattan, The Battle of Fort Washington was fought in New York on November 16, 1776, during the American Revolutionary War between the United States and Great Britain. It was a British victory that gained the surrender of the remnant of the garrison of Fort Washington near the north end of Manhattan Island. It was one of the worst Patriot defeats of the war. After defeating the Continental Army under Commander-in-Chief General George Washington at the Battle of White Plains, the British Army forces under the command of Lieutenant General William Howe planned to capture Fort Washington, the last American stronghold on Manhattan. General Washington issued a discretionary order to General Nathanael Greene to abandon the fort and remove its garrison – then numbering 1,200 men but which later grew to 3,000 – to New Jersey. Colonel Robert Magaw, commanding the fort, declined to abandon it as he believed it could be defended from the British. Howe's forces attacked the fort before Washington reached it to assess the situation. Howe launched his attack on November 16. He led an assault from three sides: the north, east and south. Tides in the Harlem River prevented some troops from landing and delayed the attack. When the British moved against the defenses, the southern and western American defenses fell quickly. Patriot forces on the north side offered stiff resistance to the Hessian attack, but they too were eventually overwhelmed. With the fort surrounded by land and sea, Colonel Magaw chose to surrender. A total of 59 Americans were killed in action and 2,837 were taken as prisoners of war. After this defeat, most of Washington's army was chased across New Jersey and into Pennsylvania, and the British consolidated their control of New York Harbor and eastern New Jersey. Battle of Harlem HeightsMorningside Heights, Manhattan The Battle of Harlem Heights was fought during the New York and New Jersey campaign of the American Revolutionary War. The action took place on September 16, 1776, in what is now the Morningside Heights area and east into the future Harlem neighborhoods of northwestern Manhattan Island in what is now part of New York City. The Continental Army, under Commander-in-chief General George Washington, Major General Nathanael Greene, and Major General Israel Putnam, totaling around 9,000 men, held a series of high ground positions in upper Manhattan. Immediately opposite was the vanguard of the British Army totaling around 5,000 men under the command of Major General Henry Clinton. Battle of Valcour IslandLake Champlain The Battle of Valcour Island, also known as the Battle of Valcour Bay, was a naval engagement that took place on October 11, 1776, on Lake Champlain. The main action took place in Valcour Bay, a narrow strait between the New York mainland and Valcour Island. The battle is generally regarded as one of the first naval battles of the American Revolutionary War, and one of the first fought by the United States Navy. Most of the ships in the American fleet under the command of Benedict Arnold were captured or destroyed by a British force under the overall direction of General Guy Carleton. However, the American defense of Lake Champlain stalled British plans to reach the upper Hudson River valley. The Continental Army had retreated from Quebec to Fort Ticonderoga and Fort Crown Point in June 1776 after British forces were massively reinforced. They spent the summer of 1776 fortifying those forts and building additional ships to augment the small American fleet already on the lake. General Carleton had a 9,000 man army at Fort Saint-Jean, but needed to build a fleet to carry it on the lake. The Americans, during their retreat, had either taken or destroyed most of the ships on the lake. By early October, the British fleet, which significantly outgunned the American fleet, was ready for launch. Battle of White PlainsWhite Plains, New York, USA The Battle of White Plains was a battle in the New York and New Jersey campaign of the American Revolutionary War, fought on October 28, 1776 near White Plains, New York. Following the retreat of George Washington's Continental Army northward from New York City, British General William Howe landed troops in Westchester County, intending to cut off Washington's escape route. Alerted to this move, Washington retreated farther, establishing a position in the village of White Plains but failed to establish firm control over local high ground. Howe's troops drove Washington's troops from a hill near the village; following this loss, Washington ordered the Americans to retreat farther north. Later British movements chased Washington across New Jersey and into Pennsylvania. Washington then crossed the Delaware and surprised a brigade of Hessian troops in the December 26 Battle of Trenton. George Washington's crossing of the Delaware RiverWashington's Crossing Battle of TrentonTrenton, NJ Battle of the Assunpink CreekTrenton, New Jersey, USA The Battle of the Assunpink Creek, also known as the Second Battle of Trenton, was a battle between American and British troops that took place in and around Trenton, New Jersey, on January 2, 1777, during the American Revolutionary War, and resulted in an American victory. Following the victory at the Battle of Trenton early in the morning of December 26, 1776, General George Washington of the Continental Army and his council of war expected a strong British counterattack. Washington and the council decided to meet this attack in Trenton and established a defensive position south of the Assunpink Creek. Lieutenant General Charles Cornwallis led the British forces southward in the aftermath of the December 26 battle. Leaving 1,400 men under Lieutenant Colonel Charles Mawhood in Princeton, Cornwallis advanced on Trenton with about 5,000 men on January 2. His advance was significantly slowed by defensive skirmishing by American riflemen under the command of Edward Hand, and the advance guard did not reach Trenton until twilight. After assaulting the American positions three times and being repulsed each time, Cornwallis decided to wait and finish the battle the next day. Washington moved his army around Cornwallis's camp that night and attacked Mawhood at Princeton the next day. That defeat prompted the British to withdraw from most of New Jersey for the winter. Battle of PrincetonPrinceton, New Jersey, USA After defeating the Hessians at the Battle of Trenton on the morning of December 26, 1776, Washington withdrew back to Pennsylvania. He subsequently decided to attack the British forces before going into winter quarters. On December 29, he led his army back into Trenton. On the night of January 2, 1777, Washington repulsed a British attack at the Battle of the Assunpink Creek. That night, he evacuated his position, circled around General Cornwallis' army, and went to attack the British garrison at Princeton. On January 3, Brigadier General Hugh Mercer of the Continental Army clashed with two regiments under the command of Mawhood. Mercer and his troops were overrun, and Mercer was mortally wounded. Washington sent a brigade of militia under Brigadier General John Cadwalader to help them. The militia, on seeing the flight of Mercer's men, also began to flee. Washington rode up with reinforcements and rallied the fleeing militia. He then led the attack on Mawhood's troops, driving them back. Mawhood gave the order to retreat, and most of the troops tried to flee to Cornwallis in Trenton. In Princeton, Brigadier General John Sullivan encouraged some British troops who had taken refuge in Nassau Hall to surrender, ending the battle. After the battle, Washington moved his army to Morristown, and with their third defeat in 10 days, the British evacuated Central Jersey. The battle (while considered minor by British standards) was the last major action of Washington's winter New Jersey campaign. Meigs RaidSag Harbor, NY, USA The Meigs Raid (also known as the Battle of Sag Harbor) was a military raid by American Continental Army forces, under the command of Connecticut Colonel Return Jonathan Meigs, on a British Loyalist foraging party at Sag Harbor, New York on May 24, 1777 during the American Revolutionary War. Six Loyalists were killed and 90 captured while the Americans suffered no casualties. The raid was made in response to a successful British raid on Danbury, Connecticut in late April that was opposed by American forces in the Battle of Ridgefield. Organized in New Haven, Connecticut by Brigadier General Samuel Holden Parsons, the expedition crossed Long Island Sound from Guilford on May 23, dragged whaleboats across the North Fork of Long Island, and raided Sag Harbor early the next morning, destroying boats and supplies. The battle marked the first American victory in the state of New York after New York City and Long Island had fallen in the British campaign for the city in 1776. Siege of Fort TiconderogaFort Ticonderoga, Fort Ti Road The 1777 Siege of Fort Ticonderoga occurred between the 2nd and 6 July 1777 at Fort Ticonderoga, near the southern end of Lake Champlain in the state of New York. Lieutenant General John Burgoyne's 8,000-man army occupied high ground above the fort, and nearly surrounded the defenses. These movements precipitated the occupying Continental Army, an under-strength force of 3,000 under the command of General Arthur St. Clair, to withdraw from Ticonderoga and the surrounding defenses. Some gunfire was exchanged, and there were some casualties, but there was no formal siege and no pitched battle. Burgoyne's army occupied Fort Ticonderoga and Mount Independence, the extensive fortifications on the Vermont side of the lake, without opposition on 6 July. Advance units pursued the retreating Americans. The uncontested surrender of Ticonderoga caused an uproar in the American public and in its military circles, as Ticonderoga was widely believed to be virtually impregnable, and a vital point of defense. General St. Clair and his superior, General Philip Schuyler, were vilified by Congress. Battle of OriskanyOriskany, New York, USA The Battle of Oriskany was one of the bloodiest battles in the American Revolutionary War and a significant engagement of the Saratoga campaign. On August 6, 1777, a party of Loyalists and several hundred Indigenous allies across several nations ambushed an American military party that was marching to relieve the siege of Fort Stanwix. This was one of the few battles in which the majority of the participants were Americans; Rebels and allied Oneidas fought against Loyalists and allied Iroquois in the absence of British regular soldiers. There was also a detachment of Hessians in the British force, as well as Western Indians including members of the Mississauga people. Battle of BenningtonWalloomsac, New York, USA The Battle of Bennington was a battle of the American Revolutionary War, part of the Saratoga campaign, that took place on August 16, 1777, in Walloomsac, New York, about 10 miles (16 km) from its namesake, Bennington, Vermont. A rebel force of 2,000 men, primarily New Hampshire and Massachusetts militiamen, led by General John Stark, and reinforced by Vermont militiamen led by Colonel Seth Warner and members of the Green Mountain Boys, decisively defeated a detachment of General John Burgoyne's army led by Lieutenant Colonel Friedrich Baum, and supported by additional men under Lieutenant Colonel Heinrich von Breymann. Battle of BrandywineChadds Ford, Pennsylvania, USA The Battle of Brandywine, also known as the Battle of Brandywine Creek, was fought between the American Continental Army of General George Washington and the British Army of General Sir William Howe on September 11, 1777, as part of the American Revolutionary War (1775–1783). The forces met near Chadds Ford, Pennsylvania. More troops fought at Brandywine than any other battle of the American Revolution. It was also the second single-day battle of the war, after the Battle of Monmouth, with continuous fighting for 11 hours. As Howe moved to take Philadelphia, then the American capital, the British forces routed the Continental Army and forced them to withdraw, first, to the City of Chester, Pennsylvania, and then northeast toward Philadelphia. Howe's army departed from Sandy Hook, New Jersey, across New York Bay from the occupied town of New York City on the southern tip of Manhattan Island, on July 23, 1777, and landed near present-day Elkton, Maryland, at the point of the "Head of Elk" by the Elk River at the northern end of the Chesapeake Bay, at the southern mouth of the Susquehanna River.Marching north, the British Army brushed aside American light forces in a few skirmishes. General Washington offered battle with his army posted behind Brandywine Creek, off the Christina River. While part of his army demonstrated in front of Chadds Ford, Howe took the bulk of his troops on a long march that crossed the Brandywine far beyond Washington's right flank. Due to poor scouting, the Americans did not detect Howe's column until it reached a position in rear of their right flank. Belatedly, three divisions were shifted to block the British flanking force at Birmingham Friends Meetinghouse and School, a Quaker meeting house. After a stiff fight, Howe's wing broke through the newly formed American right wing which was deployed on several hills. At this point Lieutenant General Wilhelm von Knyphausen attacked Chadds Ford and crumpled the American left wing. As Washington's army streamed away in retreat, he brought up elements of General Nathanael Greene's division which held off Howe's column long enough for his army to escape to the northeast. Polish General Casimir Pulaski defended Washington's rear assisting in his escape. The defeat and subsequent maneuvers left Philadelphia vulnerable. The British captured it two weeks later on September 26, resulting in the city falling under British control for nine months, until June of 1778. Battles of SaratogaStillwater, Saratogy County Battle of PaoliWillistown Township, PA, USA The Battle of Paoli (also known as the Battle of Paoli Tavern or the Paoli Massacre) was a battle in the Philadelphia campaign of the American Revolutionary War fought on September 20, 1777, in the area surrounding present-day Malvern, Pennsylvania. Following the American retreats at the Battle of Brandywine and the Battle of the Clouds, George Washington left a force under Brigadier General Anthony Wayne behind to monitor and harass the British as they prepared to move on the revolutionary capital of Philadelphia. On the evening of September 20, British forces under Major General Charles Grey led a surprise attack on Wayne's encampment near the Paoli Tavern. Although there were relatively few American casualties, claims were made that the British took no prisoners and granted no quarter, and the engagement became known as the "Paoli Massacre." Battle of GermantownGermantown, Philadelphia, Penn The Battle of Germantown was a major engagement in the Philadelphia campaign of the American Revolutionary War. It was fought on October 4, 1777, at Germantown, Pennsylvania, between the British Army led by Sir William Howe, and the American Continental Army, with the 2nd Canadian Regiment, under George Washington. Battle of Red BankFort Mercer, Hessian Avenue, N The Battle of Red Bank was a battle fought on October 22, 1777 during the American Revolutionary War in which a British and Hessian force was sent to take Fort Mercer on the left bank (or New Jersey side) of the Delaware River just south of Philadelphia, but was decisively defeated by a far inferior force of Colonial defenders. Although the British did take Fort Mercer a month later, the victory supplied a sorely-needed morale boost to the American cause, delayed British plans to consolidate gains in Philadelphia, and relieved pressure on General George Washington's army to the north of the city. Battle of White MarshWhitemarsh Township, Montgomer The Battle of White Marsh or Battle of Edge Hill was a battle of the Philadelphia campaign of the American Revolutionary War fought December 5–8, 1777, in the area surrounding Whitemarsh Township, Pennsylvania. The battle, which took the form of a series of skirmish actions, was the last major engagement of 1777 between British and American forces. George Washington, commander-in-chief of the American revolutionary forces, spent the weeks after his defeat at the Battle of Germantown encamped with the Continental Army in various locations throughout Montgomery County, just north of British-occupied Philadelphia. In early November, the Americans established an entrenched position approximately 16 miles (26 km) north of Philadelphia along the Wissahickon Creek and Sandy Run, primarily situated on several hills between Old York Road and Bethlehem Pike. From here, Washington monitored British troop movements in Philadelphia and evaluated his options. On December 4, Gen. Sir William Howe, the commander-in-chief of British forces in North America, led a sizable contingent of troops out of Philadelphia in one last attempt to destroy Washington and the Continental Army before the onset of winter. After a series of skirmishes, Howe called off the attack and returned to Philadelphia without engaging Washington in a decisive conflict. With the British back in Philadelphia, Washington was able to march his troops to winter quarters at Valley Forge. Valley ForgeValley Forge, PA Valley Forge functioned as the third of eight winter encampments for the Continental Army's main body, commanded by General George Washington, during the American Revolutionary War. In September 1777, Congress fled Philadelphia to escape the British capture of the city. Treaty of AllianceParis, France The Treaty of Alliance, also known as the Franco-American Treaty, was a defensive alliance between the Kingdom of France and the United States of America formed amid the American Revolutionary War with Great Britain. It was signed by delegates of King Louis XVI and the Second Continental Congress in Paris ( led by Benjamin Franklin) on February 6, 1778, along with the Treaty of Amity and Commerce and a secret clause providing for the entry of other European allies; together these instruments are sometimes known as the Franco-American Alliance or the Treaties of Alliance. The agreements marked the official entry of the United States on the world stage, and formalized French recognition and support of U.S. independence that was to be decisive in America's victory. Battle of Barren HillLafayette Hill, PA, USA The Battle of Barren Hill was a minor engagement during the American Revolution. On May 20, 1778, a British force attempted to encircle a smaller Continental force under the Marquis de Lafayette. The maneuver failed, with the Continentals escaping the trap, but the British took the field. Battle of MonmouthFreehold Township, NJ Southern theater of the American Revolutionary WarGeorgia, USA The Southern theater of the American Revolutionary War was the central theater of military operations in the second half of the American Revolutionary War, 1778–1781. It encompassed engagements primarily in Virginia, Georgia and South Carolina. Tactics consisted of both strategic battles and guerrilla warfare. During the first three years of the conflict, 1775–1778, the largest military encounters between Continental Army and the British Army had been in the New England and Middle colonies, around the cities of Boston, New York, and Philadelphia. After the failure of the Saratoga campaign, the British Army largely abandoned operations in the north and pursued peace through subjugation in the Southern Colonies. Before 1778, these colonies were largely dominated by Patriot-controlled governments and militias, although there was also a Continental Army presence that played a role in the 1776 defense of Charleston, the suppression of loyalist militias, and attempts to drive the British from strongly loyalist East Florida. The British began to implement their "Southern Strategy" in late 1778, in Georgia. It initially achieved success with the capture of Savannah, Georgia, which was followed in 1780 by operations in South Carolina that included the defeat of Continental forces at Charleston and Camden. At the same time France (in 1778) and Spain (in 1779) declared war on Great Britain in support of the United States. Spain captured all of British West Florida, culminating in the siege of Pensacola in 1781. France initially offered only naval support for the first few years after its declaration of war but in 1781 sent massive numbers of soldiers to join General George Washington's army and marched into Virginia from New York. General Nathanael Greene, who took over as Continental Army commander after Camden, engaged in a strategy of avoidance and attrition against the British. Cherry Valley massacreCherry Valley, New York, USA The Cherry Valley massacre was an attack by British and Iroquois forces on a fort and the village of Cherry Valley in central New York on November 11, 1778, during the American Revolutionary War. It has been described as one of the most horrific frontier massacres of the war. A mixed force of Loyalists, British soldiers, Seneca and Mohawks descended on Cherry Valley, whose defenders, despite warnings, were unprepared for the attack. During the raid, the Seneca in particular targeted non-combatants, and reports state that 30 such individuals were slain, in addition to a number of armed defenders. Capture of SavannahSavannah, Georgia The Capture of Savannah, or sometimes the First Battle of Savannah (because of the siege of 1779), or the Battle of Brewton Hill, was an American Revolutionary War battle fought on December 29, 1778 pitting local American Patriot militia and Continental Army units, holding the City, against a British invasion force under the command of Lieutenant Colonel Archibald Campbell. The British capture of the city led to an extended occupation and was the opening move in the British southern strategy to regain control of the rebellious Southern provinces by appealing to the relatively strong Loyalist sentiment there. Gulf Coast campaignPensacola, FL, USA The Gulf Coast campaign or the Spanish conquest of West Florida in the American Revolutionary War, was a series of military operations primarily directed by the governor of Spanish Louisiana, Bernardo de Gálvez against the British province of West Florida. Begun with operations against British positions on the Mississippi River shortly after Britain and Spain went to war in 1779, Gálvez completed the conquest of West Florida in 1781 with the successful siege of Pensacola. Chesapeake raidChesapeake Bay Spain and the American Revolutionary WarFlorida, USA Spain played an important role in the independence of the United States, as part of its conflict with Britain. Spain declared war on Britain as an ally of France, itself an ally of the American colonies. Most notably, Spanish forces attacked British positions in the south and captured West Florida from Britain in the siege of Pensacola. This secured the southern route for supplies and closed off the possibility of any British offensive through the western frontier of the United States via the Mississippi River. Spain also provided money, supplies, and munitions to the American forces. Beginning in 1776, it jointly funded Roderigue Hortalez and Company, a trading company that provided critical military supplies. Spain provided financing for the final siege of Yorktown in 1781 with a collection of gold and silver in Havana, then Spanish Cuba. Spain was allied with France through the Bourbon Family Compact and the Revolution was an opportunity to confront their common enemy, Great Britain. As the newly appointed Chief Minister of King Charles III of Spain, the Count of Floridablanca wrote in March 1777, "the fate of the colonies interests us very much, and we shall do for them everything that circumstances permit". Spanish aid was supplied to the new nation through four main routes: from French ports with the funding of Rodrigue Hortalez and Company, through the port of New Orleans and up the Mississippi River, from the warehouses in Havana, and from Bilbao, through the Gardoqui family trading company. Battle of Stony PointStony Point, New York, U.S. The Battle of Stony Point took place on July 16, 1779, during the American Revolutionary War. In a well-planned and -executed nighttime attack, a highly trained select group of George Washington's Continental Army troops under the command of Brigadier General "Mad Anthony" Wayne defeated British troops in a quick and daring assault on their outpost in Stony Point, New York, approximately 30 mi (48 km) north of New York City. The British suffered heavy losses in a battle that served as an important victory in terms of morale for the Continental Army. While the fort was ordered evacuated quickly after the battle by General Washington, this key crossing site was used later in the war by units of the Continental Army to cross the Hudson River on their way to victory over the British. Capture of Fort ButeEast Baton Rouge Parish, LA, U The Capture of Fort Bute signalled the opening of Spanish intervention in the American Revolutionary War on the side of France and the United States. Mustering an ad hoc army of Spanish regulars, Acadian militia, and native levies under Gilbert Antoine de St. Maxent, Bernardo de Gálvez, the Governor of Spanish Louisiana stormed and captured the small British frontier post on Bayou Manchac on September 7, 1779. Battle of Lake PontchartrainLake Pontchartrain, Louisiana, The Battle of Lake Pontchartrain was a single-ship action on September 10, 1779, part of the Anglo-Spanish War. It was fought between the British sloop-of-war HMS West Florida and the Continental Navy schooner USS Morris in the waters of Lake Pontchartrain, then in the British province of West Florida. West Florida was patrolling on Lake Pontchartrain when it encountered Morris, which had set out from New Orleans with a Spanish and American crew headed by Continental Navy Captain William Pickles. The larger crew of Morris successfully boarded West Florida, inflicting a mortal wound on its captain, Lieutenant John Payne. The capture of West Florida eliminated the major British naval presence on the lake, weakening already tenuous British control over the western reaches of West Florida. Battle of Baton RougeBaton Rouge, LA, USA The Battle of Baton Rouge was a brief siege during the Anglo-Spanish War that was decided on September 21, 1779. Baton Rouge was the second British outpost to fall to Spanish arms during Bernardo de Gálvez's march into British West Florida. Siege of SavannahSavannah, Georgia, United Stat The siege of Savannah or the Second Battle of Savannah was an encounter of the American Revolutionary War (1775–1783) in 1779. The year before, the city of Savannah, Georgia, had been captured by a British expeditionary corps under Lieutenant-Colonel Archibald Campbell. The siege itself consisted of a joint Franco-American attempt to retake Savannah, from September 16 to October 18, 1779. On October 9 a major assault against the British siege works failed. During the attack, Polish nobleman Count Casimir Pulaski, leading the combined cavalry forces on the American side, was mortally wounded. With the failure of the joint attack, the siege was abandoned, and the British remained in control of Savannah until July 1782, near the end of the war. In 1779, more than 500 recruits from Saint-Domingue (the French colony which later became Haiti), under the overall command of French nobleman Charles Hector, Comte d'Estaing, fought alongside American colonial troops against the British Army during the siege of Savannah. This was one of the most significant foreign contributions to the American Revolutionary War. This French-colonial force had been established six months earlier and included hundreds of soldiers of color in addition to white soldiers and a couple of enslaved black men. Battle of Cape St. VincentCape St. Vincent, Sagres, Port The Battle of Cape St. Vincent (Spanish: Batalla del Cabo de San Vicente) was a naval battle that took place off the southern coast of Portugal on 16 January 1780 during the American Revolutionary War. A British fleet under Admiral Sir George Rodney defeated a Spanish squadron under Don Juan de Lángara. The battle is sometimes referred to as the Moonlight Battle (batalla a la luz de la luna) because it was unusual for naval battles in the Age of Sail to take place at night. It was also the first major naval victory for the British over their European enemies in the war and proved the value of copper-sheathing the hulls of warships. Battle of Fort CharlotteMobile, Alabama, USA The Battle of Fort Charlotte or the siege of Fort Charlotte was a two-week siege conducted by Spanish General Bernardo de Gálvez against the British fortifications guarding the port of Mobile (which was then in the British province of West Florida, and now in Alabama) during the Anglo-Spanish War of 1779-1783. Fort Charlotte was the last remaining British frontier post capable of threatening New Orleans in Spanish Louisiana. Its fall drove the British from the western reaches of West Florida and reduced the British military presence in West Florida to its capital, Pensacola. Gálvez's army sailed from New Orleans aboard a small fleet of transports on January 28, 1780. On February 25, the Spaniards landed near Fort Charlotte. The outnumbered British garrison resisted stubbornly until Spanish bombardment breached the walls. The garrison commander, Captain Elias Durnford, had waited in vain for relief from Pensacola, but was forced to surrender. Their capitulation secured the western shore of Mobile Bay and opened the way for Spanish operations against Pensacola. Siege of CharlestonCharleston, South Carolina Battle of St. LouisSt. Louis, MO, USA The Battle of St. Louis was an unsuccessful attack led by the British on St. Louis (a French settlement in Spanish Louisiana, founded on the West Bank of the Mississippi River after the 1763 Treaty of Paris) on May 26, 1780, during the American Revolutionary War. A former British militia commander led a force primarily of Indians and attacked the settlement. Fernando de Leyba, the Lieutenant Governor of Spanish Louisiana, led the local militia to fortify the town as best as they could and successfully withstood the attack. On the opposite bank of the Mississippi, a second simultaneous attack on the nearby former British colonial outpost of Cahokia, occupied by Patriot Virginians, was also repulsed. The retreating Indians destroyed the crops and took captive civilians outside the protected area. The British failed to defend their side of the river and, thus, effectively ended any attempts to gain control of the Mississippi River during the war. Battle of Hanging RockLancaster County, South Caroli The Battle of Hanging Rock (August 6, 1780) was a battle in the American Revolutionary War that occurred between the American Patriots and the British. It was part of a campaign by militia General Thomas Sumter to harass or destroy British outposts in the South Carolina back-country that had been established after the fall of Charleston in May 1780. Future President Andrew Jackson (aged 13) and his brother Robert partook in the battle. Battle of CamdenKershaw County Battle of Kings MountainSouth Carolina, USA The Battle of Kings Mountain was a military engagement between Patriot and Loyalist militias in South Carolina during the Southern Campaign of the American Revolutionary War, resulting in a decisive victory for the Patriots. The battle took place on October 7, 1780, 9 miles (14 km) south of the present-day town of Kings Mountain, North Carolina. In what is now rural Cherokee County, South Carolina, the Patriot militia defeated the Loyalist militia commanded by British Major Patrick Ferguson of the 71st Foot. The battle has been described as "the war's largest all-American fight". Yorktown campaignYorktown, VA, USA The Yorktown or Virginia campaign was a series of military maneuvers and battles during the American Revolutionary War that culminated in the siege of Yorktown in October 1781. The result of the campaign was the surrender of the British Army force of General Charles Earl Cornwallis, an event that led directly to the beginning of serious peace negotiations and the eventual end of the war. The campaign was marked by disagreements, indecision, and miscommunication on the part of British leaders, and by a remarkable set of cooperative decisions, at times in violation of orders, by the French and Americans. The campaign involved land and naval forces of Great Britain and France, and land forces of the United States. British forces were sent to Virginia between January and April 1781 and joined with Cornwallis's army in May, which came north from an extended campaign through the southern states. These forces were first opposed weakly by Virginia militia, but General George Washington sent first Marquis de Lafayette and then "Mad" Anthony Wayne with Continental Army troops to oppose the raiding and economic havoc the British were wreaking. The combined American forces, however, were insufficient in number to oppose the combined British forces, and it was only after a series of controversially confusing orders by General Sir Henry Clinton, the British commander-in-chief, that Cornwallis moved to Yorktown in July and built a defensive position that was strong against the land forces he then faced, but was vulnerable to naval blockade and siege. British naval forces in North America and the West Indies were weaker than the combined fleets of France and Spain, and, after some critical decisions and tactical missteps by British naval commanders, the French fleet of Paul de Grasse gained control over Chesapeake Bay, blockading Cornwallis from naval support and delivering additional land forces to blockade him on land. The Royal Navy attempted to dispute this control, but Admiral Thomas Graves was defeated in the key Battle of the Chesapeake on September 5. American and French armies that had massed outside New York City began moving south in late August, and arrived near Yorktown in mid-September. Deceptions about their movement successfully delayed attempts by Clinton to send more troops to Cornwallis. The siege of Yorktown began on September 28, 1781. In a step that probably shortened the siege, Cornwallis decided to abandon parts of his outer defenses, and the besiegers successfully stormed two of his redoubts. When it became clear that his position was untenable, Cornwallis opened negotiations on October 17 and surrendered two days later. When the news reached London, the government of Lord North fell, and the following Rockingham ministry entered into peace negotiations. These culminated in the Treaty of Paris in 1783, in which King George III recognized the independent United States of America. Clinton and Cornwallis engaged in a public war of words defending their roles in the campaign, and British naval command also discussed the navy's shortcomings that led to the defeat. Battle of MobileMobile, AL, USA The 2nd Battle of Mobile, also known as the Battle at the Village, was a British attempt to recapture the town of Mobile, in the British province of West Florida, from the Spanish during the Anglo-Spanish War. The Spanish had previously captured Mobile in March 1780. On January 7, 1781, a British attack against a Spanish outpost on the Eastern Shore of Mobile Bay was repulsed, and the German leader of the expedition was killed. Battle of CowpensCherokee County, South Carolin Siege of PensacolaPensacola, FL, USA The siege of Pensacola was a siege fought in 1781, the culmination of Spain's conquest of the British province of West Florida during the Gulf Coast campaign. Battle of Guilford Court HouseGreensboro, North Carolina Lochry's DefeatAurora, Indiana, USA Lochry's Defeat, also known as the Lochry massacre, was a battle fought on August 24, 1781, near present-day Aurora, Indiana, in the United States. The battle was part of the American Revolutionary War (1775–1783), which began as a conflict between Great Britain and the Thirteen Colonies before spreading to the western frontier, where American Indians entered the war as British allies. The battle was short and decisive: about one hundred Indians of local tribes led by Joseph Brant, a Mohawk military leader who was temporarily in the west, ambushed a similar number of Pennsylvania militiamen led by Archibald Lochry. Brant and his men killed or captured all of the Pennsylvanians without suffering any casualties. Battle of the ChesapeakeCape Charles, VA, USA The Battle of the Chesapeake, also known as the Battle of the Virginia Capes or simply the Battle of the Capes, was a crucial naval battle in the American Revolutionary War that took place near the mouth of the Chesapeake Bay on 5 September 1781. The combatants were a British fleet led by Rear Admiral Sir Thomas Graves and a French fleet led by Rear Admiral François Joseph Paul, the Comte de Grasse. The battle was strategically decisive, in that it prevented the Royal Navy from reinforcing or evacuating the besieged forces of Lieutenant General Lord Cornwallis at Yorktown, Virginia. The French were able to achieve control of the sea lanes against the British and provided the Franco-American army with siege artillery and French reinforcements. These proved decisive in the Siege of Yorktown, effectively securing independence for the Thirteen Colonies. Admiral de Grasse had the option to attack British forces in either New York or Virginia; he opted for Virginia, arriving at the Chesapeake at the end of August. Admiral Graves learned that de Grasse had sailed from the West Indies for North America and that French Admiral de Barras had also sailed from Newport, Rhode Island. He concluded that they were going to join forces at the Chesapeake. He sailed south from Sandy Hook, New Jersey, outside New York Harbor, with 19 ships of the line and arrived at the mouth of the Chesapeake early on 5 September to see de Grasse's fleet already at anchor in the bay. De Grasse hastily prepared most of his fleet for battle—24 ships of the line—and sailed out to meet him. Battle of Eutaw SpringsEutawville, South Carolina Siege of YorktownYorktown, VA The siege of Yorktown, also known as the Battle of Yorktown, the surrender at Yorktown, or the German battle, ending on October 19, 1781, at Yorktown, Virginia, was a decisive victory by a combined force of the American Continental Army troops led by General George Washington and Gilbert du Motier, Marquis de Lafayette, and French Army troops led by Comte de Rochambeau over a British army commanded by British peer and Lieutenant General Charles Cornwallis. The culmination of the Yorktown campaign, the siege proved to be the last major land battle of the American Revolutionary War in the North American region, as the surrender by Cornwallis, and the capture of both him and his army, prompted the British government to negotiate an end to the conflict. Battle of JohnstownJohnstown, New York, USA The Battle of Johnstown was one of the last battles in the northern theatre of the American Revolutionary War, with approximately 1,400 engaged at Johnstown, New York on October 25, 1781. Local American forces, led by Colonel Marinus Willett of Johnstown, ultimately put to flight the British forces under the command of Major John Ross of the King's Royal Regiment of New York and Captain Walter Butler of Butler's Rangers. This was the first time so many British regular army troops participated in a border raid in this area. The British retreated northwards and Marinus Willett marched to German Flatts to try to cut them off. The British managed to escape, but Walter Butler was killed. Battle of the SaintesDominica The Battle of the Saintes (known to the French as the Bataille de la Dominique), also known as the Battle of Dominica, was an important naval battle in the Caribbean between the British and the French that took place 9–12 April 1782. The British victory was considered their greatest over the French during the American Revolutionary War. Battle of Blue LicksMount Olivet, Kentucky, USA The Battle of Blue Licks, fought on August 19, 1782, was one of the last battles of the American Revolutionary War. The battle occurred ten months after Lord Cornwallis's surrender at Yorktown, which had effectively ended the war in the east. On a hill next to the Licking River in what is now Robertson County, Kentucky (then Fayette County, Virginia), a force of about 50 Loyalists along with 300 indigenous warriors ambushed and routed 182 Kentucky militiamen. It was the last victory for the Loyalists and natives during the frontier war. British, Loyalist and Native forces would engage in fighting with American forces once more the following month in Wheeling, West Virginia, during the Siege of Fort Henry. Treaty of ParisParis, France The Treaty of Paris, signed in Paris by representatives of King George III of Great Britain and representatives of the United States of America on September 3, 1783, officially ended the American Revolutionary War. EpilogueNew England, USA The conflict between British subjects with the Crown against those with the Congress had lasted over eight years from 1775 to 1783. The last uniformed British troops departed their last east coast port cities in Savannah, Charleston, and New York City, by November 25, 1783. That marked the end of British occupation in the new United States. Of the European powers with American colonies adjacent to the newly created United States, Spain was most threatened by American independence, and it was correspondingly the most hostile to it. Casualties and losses Up to 70,000 American Patriots died during active military service. Of these, approximately 6,800 were killed in battle, while at least 17,000 died from disease. The majority of the latter died while prisoners of war of the British, mostly in the prison ships in New York Harbor. The number of Patriots seriously wounded or disabled by the war has been estimated from 8,500 to 25,000. The French suffered 2,112 killed in combat in the United States. The Spanish lost a total of 124 killed and 247 wounded in West Florida. A British report in 1781 puts their total Army deaths at 6,046 in North America (1775–1779). Approximately 7,774 Germans died in British service in addition to 4,888 deserters; of the former, it is estimated 1,800 were killed in combat. The American Revolution established the United States with its numerous civil liberties and set an example to overthrow both monarchy and colonial governments. The United States has the world's oldest written constitution, and the constitutions of other free countries often bear a striking resemblance to the US Constitution, often word-for-word in places. It inspired the French, Haitian, Latin American Revolutions, and others into the modern era. - Allison, David, and Larrie D. Ferreiro, eds. The American Revolution: A World War (Smithsonian, 2018) excerpt - Bancroft, George (1854–1878). History of the United States of America, from the discovery of the American continent – eight volumes. - Volumes committed to the American Revolution: Vol. 7; Vol. 8; Vol. 9; Vol. 10 - Bobrick, Benson. Angel in the Whirlwind: The Triumph of the American Revolution. Penguin, 1998 (paperback reprint) - British Army (1916) [7 August 1781]. Proceedings of a Board of general officers of the British army at New York, 1781. New-York Historical Society. Collections. The John Watts de Peyster publication fund series, no. 49. New York Historical Society. The board of inquiry was convened by Sir Henry Clinton into Army accounts and expenditures - Burgoyne, John (1780). A state of the expedition from Canada : as laid before the House of commons. London : Printed for J. Almon. - Butterfield, Lyman H. (June 1950). "Psychological Warfare in 1776: The Jefferson-Franklin Plan to Cause Hessian Desertions". Proceedings of the American Philosophical Society. American Philosophical Society. 94 (3): 233–241. JSTOR 3143556. - Cate, Alan C. (2006). Founding Fighters: The Battlefield Leaders Who Made American Independence. Greenwood Publishing Group. ISBN 0275987078. - Caughey, John W. (1998). Bernardo de Gálvez in Louisiana 1776–1783. Gretna: Pelican Publishing Company. ISBN 978-1-56554-517-5. - Chartrand, Rene. The French Army in the American War of Independence (1994). Short (48pp), very well illustrated descriptions. - Christie, Ian R.; Labaree, Benjamin W. (1976). Empire or independence, 1760–1776. Phaidon Press. ISBN 978-0-7148-1614-2. - Clarfield, Gerard (1992). United States Diplomatic History: From Revolution to Empire. New Jersey: Prentice-Hall. ISBN 9780130292322. - Clode, Charles M. (1869). The military forces of the crown; their administration and government. Vol. 2. London, J. Murray. - Commager, Henry Steele and Richard B. Morris, eds. The Spirit of 'Seventy-Six': The Story of the American Revolution as told by Participants. (Indianapolis: Bobbs-Merrill, 1958). online - Conway, Stephen. The War of American Independence 1775–1783. Publisher: E. Arnold, 1995. ISBN 0340625201. 280 pp. - Creigh, Alfred (1871). History of Washington County. B. Singerly. p. 49. ann hupp indian. - Cook, Fred J. (1959). What Manner of Men. William Morrow and Co. 59-11702. Allan McLane, Chapter VIII, pp. 275–304 - Davies, Wallace Evan (July 1939). "Privateering around Long Island during the Revolution". New York History. Fenimore Art Museum. 20 (3): 283–294. JSTOR 23134696. - Downes, Randolph C. (1940). Council Fires on the Upper Ohio: A Narrative of Indian Affairs in the Upper Ohio Valley until 1795. Pittsburgh: University of Pittsburgh Press. ISBN 0-8229-5201-7. - Duncan, Francis (1879). History of the Royal Regiment of Artillery. London: John Murray. - Ferling, John E. (2002) . Setting the World Ablaze: Washington, Adams, Jefferson, and the American Revolution. Oxford University Press. ISBN 978-0-19-513409-4. - Fleming, Thomas (1970). The Perils of Peace. New York: The Dial Press. ISBN 978-0-06-113911-6. - Foner, Eric, "Whose Revolution?: The history of the United States' founding from below" (review of Woody Holton, Liberty Is Sweet: The Hidden History of the American Revolution, Simon & Schuster, 2021, 800 pp.), The Nation, vol. 314, no. 8 (18–25 April 2022), pp. 32–37. Highlighted are the struggles and tragic fates of America's Indians and Black slaves. For example, "In 1779 [George] Washington dispatched a contingent of soldiers to upstate New York to burn Indian towns and crops and seize hostages 'of every age and sex.' The following year, while serving as governor of Virginia, [Thomas] Jefferson ordered troops under the command of George Rogers Clark to enter the Ohio Valley and bring about the expulsion or 'extermination' of local Indians." (pp. 34–35.) - Fortescue, John (1902). A history of the British army. Vol. 3. - Fredriksen, John C. (2006). Revolutionary War Almanac Almanacs of American wars Facts on File library of American history. Infobase Publishing. ISBN 978-0-8160-7468-6. - Freedman, Russell (2008). Washington at Valley Forge. Holiday House. ISBN 978-0823420698. - Fremont-Barnes, Gregory; Ryerson, Richard A, eds. (2006). Encyclopedia of the American Revolutionary War: A Political, Social, and Military History. ABC-CLIO. ISBN 978-1851094080. - Frey, Sylvia R (1982). The British Soldier in America: A Social History of Military Life in the Revolutionary Period. University of Texas Press. ISBN 978-0292780408. - Gilbert, Alan (2012). Black Patriots and Loyalists: Fighting for Emancipation in the War for Independence. University of Chicago Press. ISBN 978-0226101552. - Grant, John N. (1973). "Black Immigrants into Nova Scotia, 1776–1815". The Journal of Negro History. 58 (3): 253–270. doi:10.2307/2716777. JSTOR 2716777. S2CID 150064269. - Jensen, Merrill (2004). The Founding of a Nation: A History of the American Revolution 1763–1776. Hackett Publishing. ISBN 978-0-87220-705-9. - Johnston, Henry Phelps (1881). The Yorktown Campaign and the Surrender of Cornwallis, 1781. New York: Harper & Bros. p. 34. OCLC 426009. - Hagist, Don N. (Winter 2011). "Unpublished Writings of Roger Lamb, Soldier of the American War of Independence". Journal of the Society for Army Historical Research. Society for Army Historical Research. 89 (360): 280–290. JSTOR 44232931. - Kaplan, Rodger (January 1990). "The Hidden War: British Intelligence Operations during the American Revolution". The William and Mary Quarterly. Omohundro Institute of Early American History and Culture. 47 (1): 115–138. doi:10.2307/2938043. JSTOR 2938043. - Kepner, K. (February 1945). "A British View of the Siege of Charleston, 1776". The Journal of Southern History. Southern Historical Association. 11 (1): 93–103. doi:10.2307/2197961. JSTOR 2197961. - Kilmeade, Brian.; Yaeger, Don (2013). George Washington's Secret Six: The Spy Ring That Saved the American Revolution. Penguin Books. ISBN 978-0-6981-3765-3. - Knight, Peter (2003). Conspiracy Theories in American History: An Encyclopedia. ABC-CLIO. pp. 184–85. ISBN 978-1-57607-812-9. - Kohn, George C. (2006). Dictionary of Wars, 3d edition. Infobase Publishing. ISBN 9781438129167. - Kwasny, Mark V. Washington's Partisan War, 1775–1783. Kent, Ohio: 1996. ISBN 0873385462. Militia warfare. - Larabee, Leonard Woods (1959). Conservatism in Early American History. Cornell University Press. ISBN 978-0151547456. Great Seal Books - Lemaître, Georges Édouard (2005). Beaumarchais. Kessinger Publishing. ISBN 9781417985364. - Levy, Andrew (2007). The First Emancipator: Slavery, Religion, and the Quiet Revolution of Robert Carter. Random House Trade Paperbacks. p. 74. ISBN 978-0-375-76104-1. - Library of Congress "Revolutionary War: Groping Toward Peace, 1781–1783". Library: Library of Congress. Library of Congress. Retrieved August 24, 2020. - Lloyd, Earnest Marsh (1908). A review of the history of infantry. New York: Longmans, Green, and co. - May, Robin. The British Army in North America 1775–1783 (1993). Short (48pp), very well illustrated descriptions. - McGrath, Nick. "Battle of Guilford Courthouse". George Washington's Mount Vernon: Digital Encyclopedia. Mount Vernon Ladies' Association. Retrieved January 26, 2017. - Middleton, Richard (July 2013). "The Clinton–Cornwallis Controversy and Responsibility for the British Surrender at Yorktown". History. Wiley Publishers. 98 (3): 370–389. doi:10.1111/1468-229X.12014. JSTOR 24429518. - —— (2014). The War of American Independence, 1775–1783. London: Pearson. ISBN 978-0-5822-2942-6. - Miller, Ken (2014). Dangerous Guests: Enemy Captives and Revolutionary Communities During the War for Independence. Cornell University Press. ISBN 978-0-8014-5494-3. - Nash, Gary B.; Carter Smith (2007). Atlas Of American History. Infobase Publishing. p. 64. ISBN 978-1-4381-3013-2. - National Institute of Health "Scurvy". National Institute of Health. November 14, 2016. Retrieved October 1, 2020. Genetic and Rare Diseases Information Center - Neimeyer, Charles Patrick. America Goes to War: A Social History of the Continental Army (1995) JSTOR j.ctt9qg7q2 - Nicolas, Paul Harris (1845). Historical record of the Royal Marine Forces, Volume 2. London: Thomas and William Boone. port praya suffren 1781. - Ortiz, J.D. "General Bernardo Galvez in the American Revolution". Retrieved September 9, 2020. - Perkins, James Breck (2009) . France in the American Revolution. Cornell University Library. ASIN B002HMBV52. - Peters, Richard, ed. (1846). A Century of Lawmaking for a New Nation: U.S. Congressional Documents and Debates, 1774 – 1875: Treaty of Alliance with France 1778, "Article II". Library of Congress archives. - Ramsay, David (1819). Universal History Americanised: Or, An Historical View of the World, from the Earliest Records to the Year 1808. Vol. 4. Philadelphia : M. Carey & Son. - Reich, Jerome R. (1997). British friends of the American Revolution. M.E. Sharpe. p. 121. ISBN 978-0-7656-3143-5. - Ridpath, John Clark (1915). The new complete history of the United States of America. Vol. 6. Cincinnati: Jones Brothers. OCLC 2140537. - Royal Navy Museum "Ships Biscuits – Royal Navy hardtack". Royal Navy Museum. Archived from the original on October 31, 2009. Retrieved January 14, 2010. - Sawyer, C.W. (1910). Firearms in American History. Boston: C.W. Sawyer. online at Hathi Trust - Schiff, Stacy (2006). A Great Improvisation: Franklin, France, and the Birth of America. Macmillan. p. 5. ISBN 978-1-4299-0799-6. - Scribner, Robert L. (1988). Revolutionary Virginia, the Road to Independence. University of Virginia Press. ISBN 978-0-8139-0748-2. - Selig, Robert A. (1999). Rochambeau in Connecticut, Tracing His Journey: Historic and Architectural Survey. Connecticut Historical Commission. - Smith, Merril D. (2015). The World of the American Revolution: A Daily Life Encyclopedia. ABC-CLIO. p. 374. ISBN 978-1-4408-3028-0. - Southey, Robert (1831). The life of Lord Nelson. Henry Chapman Publishers. ISBN 9780665213304. - Stoker, Donald, Kenneth J. Hagan, and Michael T. McMaster, eds. Strategy in the American War of Independence: a global approach (Routledge, 2009) excerpt. - Symonds, Craig L. A Battlefield Atlas of the American Revolution (1989), newly drawn maps emphasizing the movement of military units - Trew, Peter (2006). Rodney and the Breaking of the Line. Pen & Sword Military. ISBN 978-1-8441-5143-1. - Trickey, Erick. "The Little-Remembered Ally Who Helped America Win the Revolution". Smithsonian Magazine January 13, 2017. Retrieved April 28, 2020. - Turner, Frederick Jackson (1920). The frontier in American history. New York: H. Holt and company. - Volo, M. James (2006). Blue Water Patriots: The American Revolution Afloat. Rowman & Littlefield Publishers, Inc. ISBN 978-0-7425-6120-5. - U.S. Army, "The Winning of Independence, 1777–1783" American Military History Volume I, 2005. - U.S. National Park Service "Springfield Armory". Nps.gov. April 25, 2013. Retrieved May 8, 2013. - Weir, William (2004). The Encyclopedia of African American Military History. Prometheus Books. ISBN 978-1-61592-831-6. - Whaples, Robert (March 1995). "Where Is There Consensus Among American Economic Historians? The Results of a Survey on Forty Propositions". The Journal of Economic History. 55 (1): 144. CiteSeerX 10.1.1.482.4975. doi:10.1017/S0022050700040602. JSTOR 2123771. There is an overwhelming consensus that Americans' economic standard of living on the eve of the Revolution was among the highest in the world. - Whaples, Robert (March 1995). "Where Is There Consensus Among American Economic Historians? The Results of a Survey on Forty Propositions". The Journal of Economic History. 55 (1): 144. CiteSeerX 10.1.1.482.4975. doi:10.1017/S0022050700040602. JSTOR 2123771. There is an overwhelming consensus that Americans' economic standard of living on the eve of the Revolution was among the highest in the world. - Zeller-Frederick, Andrew A. (April 18, 2018). "The Hessians Who Escaped Washington's Trap at Trenton". Journal of the American Revolution. Bruce H. Franklin. Citing William M. Dwyer and Edward J. Lowell, The Hessians: And the Other German Auxiliaries in the Revolutionary War, 1970 - Zlatich, Marko; Copeland, Peter. General Washington's Army (1): 1775–78 (1994). Short (48pp), very well illustrated descriptions. 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Language and Notation of the Circle Formal definition of a circle. Tangent and secant lines. Diameters and radii. major and minor arcs Language and Notation of the Circle ⇐ Use this menu to view and help create subtitles for this video in many different languages. You'll probably want to hide YouTube's captions if using these subtitles. - Let's start again with a point let's call that - point, "Point A." And what I'm curious about - is all of the points on my screen that are exactly - 2cm away from "Point A." So 2cm on my screen - is about that far. So clearly if I start at "A" and I go 2cm - in that direction, this point is 2cm from "A." If I call that - "Point B" then I could say line segment AB is 2cm - the length is 2cm. Remember, this would refer to - the actual line segment. I could say this looks nice but if - I talk about it's length, I would get rid of that - line on top, and I would just say, "'AB' is equal to - 2. If I wanted to put units, I would say 2cm. - But I'm not curious just about B, I want to think - about ALL the points. The set of ALL of the points - that are exactly 2cm away from "A." So I could go - 2cm in the other direction, maybe get to point - "C" right over here. So "AC" is also going to be equal - to 2cm. But I could go 2cm in any direction. And so - if I find that of all of the points that are exactly 2cm - away from "A," I will get a very familiar looking - shape, like this: (I'm drawing this free-hand,) so I would - get a shape that looks like this. Actually, let me draw - it in I don't want to make you think that it's only the - points where there's white, it's ALL of these points - right over here. Let me clear out all of these and I will - just draw a solid line. It could look something like - that (my best attempt.) And this set of all the points - that are exactly 2cm away from "A," is a circle, which - I'm sure you are already familiar with. But that is - the formal definition, the set of all points that are - a fixed distance from "A." If I said, "The set of all points - that are 3cm from "A," it might look something like this:" - That would give us another circle. (I think you get the - general idea.) Now, what I want to introduce to you - in this video is ourselves to some of the concepts - and words that we use when dealing with circles. - So let me get rid of 3cm circle. So first of all, let's - think about this distance, or one of these line segments - that join "A" which we would call the center of the - circle. So we will call "A" the center of the circle, - which makes sense just from the way we use the word - 'center' in everyday life, what I want to do is think - about what line segment "AB" is. "AB" connects the - center and it connects a point on the circle itself. - Remember, the circle itself is all the points that - are equal distance from the center. So "AB," any point, - line segment, I should say, that connects the center to - a point on the circle we would call a radius. And so - the length of the radius is 2cm. And you're probably - already familiar with the word 'radius,' but I'm just - being a little bit more formal. And what's interesting - about geometry, at least when you start learning at the - high-school level is that it's probably the first - class where you're introduced to a slightly more formal - mathematics where we're a little more careful about - giving our definitions and then building on those - definitions to come up with interesting results and - proving to ourselves that we definitely know what we - think we know. And so that's why we're being a little - more careful with our language over here. So "AB" is - a radius, line segment "AB," and so is line segment, - (let me put another point on here) let's say this is - "X" so line segment "AX" is also a radius. Now you - can also have other forms of lines and line segments - that interact in interesting ways with the circle. - So you could have a line that just intersects that - circle exactly one point. So let's call that point - right over there and let's call that "D." And let's say - you have a line and the only point on the circle that - the only point in the set of all the points that are - equal distance from "A," the only point on that - circle that is also on that line is point "D." And we - could call that line, "line L." So sometimes you will - see lines specified by some of the points on them. - So for example, if I have another point right over here - called "E," we could call this line, "line DE," or we - could just put a little script letter here with an "L" and - say this "line L." But this line that only has one point - in common with our circle, we call this 'a tangent line.' - So "Line L" is tangent. Tangent to the circle. So let me - write it this way, "'line L' is tangent to the circle - centered at "A"" So this tells us that this is the circle - we're talking about, because who knows? maybe we had - another circle over here that is centered at "M." - So we have to specify. It's not tangent to that one, - it's tangent to this one. So this circle with a dot in - the middle tells we're talking about circle, and this - is a circle centered at point "A." I want to be very - clear. Point "A" is not on the circle, point "A" is - the center of the circle. The points on the circle are - the points equal distant from point "A." Now, "L" is - tangent because it only intersects the circle in one - point. You could just as easily imagine a line that - intersects the circle at two points. So we could call, - maybe this is "F" and this is "G." You could call that - line "FG." And the line that intersects at two points - we call this a secant of circle "A." It is a secant line - to this circle right here. Because it intersects it - in two points. Now, if "FG" was just a segment, if it - didn't keep on going forever like lines do, if we only - spoke about this line segment, between "FG," and not - thinking about going on forever, then all the sudden, - we have a line segment, which we would specify there, - and we would call this a chord of the circle. A chord of - "circle "A." It starts on a point of the circle, a point - that is, in this case, 2cm away and then it finishes - at a point on the circle. So it connects two points on - the circle. Now, you can have cords like this, and you - can also have a chord, as you can imagine, a chord that - actually goes through the center of the circle. So let's - call this, "point 'H.'" And you have a straight line connecting - "F" to "H" through "A." (That's about as straight as I could - draw it.) So if you have a chord like that, that contains - actual center of the circle, of course it goes from one - point to another point of the circle, and it goes through - the center of the circle, we call that a diameter of a - circle. And you've probably seen this in tons of problems - before when we were not talking about geometry as formally, - but a diameter is made of two radiuses. We know that a radius - connects a point to the center, so you have one radius - right over here that connects "F" and "A" that's one radius - and you have another radius connecting "A" and "H," - a point connecting to the center of the circle. So the - diameter is made of these two radiuses (or radii as I - should call it I think that's the plural for radius) and so - the length of a diameter is going to be twice the length - of a radius. So we could say, "the length of the diameter, - so the length of "FH" (and once again I don't put the - line on top of it when I'm talking about the length) is - going to be equal to "FA," the length of segment "FA" plus - the length of segment "AH."" Now there's one last thing - I want to talk about, when we're dealing with circles, - and that's the idea of an arc. So we also have the parts - of the circle itself. (So let me draw another circle over - here) Let's center this circle at "B." And I'm going to find - some points, all the points that are a given distance - from "B." So, it has some radius, I'm not going to specify - it right over here. And let me pick some random points - on this circle. Let's call this, "J," "K," "S," "T," and "U." - Let me center "B" a little bit more in the center here... - Now, one interesting thing is, "what do you call - the length of the circle that goes between two points?" - Well, you could imagine in every language, we would - call something like that an "arc," which is also what it's - called in geometry. We would call this "JK," the two end - points of the arc, the two points on the circle that are - the inputs of the arc, and you would use a little notation like - that, a little curve on top instead of a strait line. - Now, you can also have another arc that connects "J" - and "K," this is called the 'minor arc,' it is the shortest - way upon the circle to connect "J" and "K." But you could - also go the other way around. You could also have this - thing, that goes all the around the circle. And that is - called the 'major arc.' And usually when we specify the - major arc, just to show that you're going kind of the long - way around, it's not the shortest way to go between - "J" and "K," you will often specify another point that you're - going through. So for example, this major arc we could - specify. We started "J," we went through, we could have - said "U," "T," or "S," but I will put "T" right over there. - We went through "T" and then we went all the way to "K." - And so this specifies the major arc. And this thing could - have been the same thing as if I wrote "JUK" these are - specifying the same thing, or "JSK." So there are - multiple ways to specify this major arc. The one thing I want - to make clear is that the minor arc is the shortest distance, - so this is the minor arc, and the longer distance around is - the major arc. I will leave you there. Maybe the next few - videos we will starts playing with some of this notation. 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Mr. Boyle - Edgewood HS - Room 203 The Study of Geometry phone: (513) 867-6300 ext. 4203 Second Semester Common Core Standards Relationships & Properties G.C.3 Construct the inscribed and circumscribed circles of a triangle, and prove properties of angles for a quadrilateral inscribed in a circle. G.SRT.1 Verify experimentally the properties of dilations given by a center and a scale factor. a. A dilation takes a line not passing through the center of the dilation to a parallel line, and leaves a line passing through the center unchanged. b. The dilation of a line segment is longer or shorter in the ratio given by the scale factor. G.SRT.2 Given two figures, use the definition of similarity in terms of similarity transformations to decide if they are similar; explain using similarity transformations the meaning of similarity for triangles as the equality of all corresponding pairs of angles and the proportionality of all corresponding pairs of sides. G.SRT.3 Use the properties of similarity transformations to establish the AA criterion for two triangles to be similar. G.SRT.4 Prove theorems about triangles. Theorems include: a line parallel to one side of a triangle divides the other two proportionally, and conversely; the Pythagorean Theorem proved using triangle similarity. G.SRT.5 Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures. G.GPE.7 Use coordinates to compute perimeters of polygons and areas of triangles and rectangles, e.g., using the distance formula.★ Circles & Conics G.C.1 Prove that all circles are similar. G.C.2 Identify and describe relationships among inscribed angles, radii, and chords. Include the relationship between central, inscribed, and circumscribed angles; inscribed angles on a diameter are right angles; the radius of a circle is perpendicular to the tangent where the radius intersects the circle. G.C.5 Derive using similarity the fact that the length of the arc intercepted by an angle is proportional to the radius, and define the radian measure of the angle as the constant of proportionality; derive the formula for the area of a sector. G.GPE.1 Derive the equation of a circle of given center and radius using the Pythagorean Theorem; complete the square to find the center and radius of a circle given by an equation. G.GPE.2 Derive the equation of a parabola given a focus and directrix. Measurement & Dimensions G.GMD.1 Give an informal argument for the formulas for the circumference of a circle, area of a circle, volume of a cylinder, pyramid, and cone. Use dissection arguments, Cavalieri’s principle, and informal limit arguments. G.GMD.3 Use volume formulas for cylinders, pyramids, cones, and spheres to solve problems.★ G.GMD.4 Identify the shapes of two-dimensional cross-sections of three- dimensional objects, and identify three-dimensional objects generated by rotations of two-dimensional objects. G.SRT.6 Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles. G.SRT.7 Explain and use the relationship between the sine and cosine of complementary angles. G.SRT.8 Use trigonometric ratios and the Pythagorean Theorem to solve right triangles in applied problems.★
In an infinite universe, most scientists agree, the odds of life existing on a planet besides Earth are pretty high. It is unlikely, however, that familiar life forms will be found on any planet within our solar system. Life as we know it—everything from single-celled organisms to human beings—consists largely of liquid water. So a planet that harbors life can't be too cold or water will freeze, nor can it be too hot or all the water will evaporate. Planets closer to the sun than Earth are too hot, and those farther away are too cold. The surface of Venus, for example, is hot enough to melt lead, and would vaporize any living thing, while the surface of Mars is frozen solid. Life as we know it here on Earth also requires a magnetic field and an atmosphere, both of which protect it from the lethal radiation our parent star, the sun, emits. Earth's magnetic field—generated by its rotating iron core—deflects the solar wind, a continuous stream of high-speed, high-energy particles coming out of the sun. (As those particles careen by the edges of Earth's atmosphere, they sometime create the phenomenon we call the Northern Lights.) Without the magnetic field there, the solar wind might destroy all life on Earth. As for Earth's atmosphere, it protects life because the water, carbon dioxide and other gases in it absorb solar radiation in its harmful ultraviolet-light form. The parent stars of other solar systems would emit radiation as well, and the planets orbiting them would need the same kind of protection. Of course, life on Earth also alters the chemical composition of the atmosphere—Earth's atmosphere lacked gaseous oxygen until plants started growing here some million years ago. So molecules like oxygen in the atmosphere of another planet would be one indication—not proof—that there are living things there. Scientists have been studying the planets of our own solar system for more than 50 years, looking for evidence of past or present life, among other things. Launched in 1967, the Soviet Union's Venera 4 was the first probe known to land on and send back data from another planet. The mission revealed that Venus' famously soupy atmosphere is made up almost entirely of carbon dioxide with a surface temperature hot enough to melt lead, making it a very unlikely place to harbor life. Today, NASA's Mars rover, Opportunity, has been sending back reams of data about the red planet since it landed there 12 years ago. Living well past all expectations, Opportunity not only transmits landscape photos and the occasional tweet, but also collects and analyzes soil and atmosphere samples. It's been an invaluable research tool, but has found no direct evidence that life ever existed on Mars, and has revealed that the planet's atmosphere is too thin to protect it from the sun's radiation. The discovery of thousands of planets orbiting nearby stars has nevertheless greatly increased speculation that there may be some kind of life on a planet outside our solar system. In the past 20 years, we have confirmed the discovery of almost 2,000 planets, called exoplanets, beyond our solar system. Four thousand other exoplanet candidates await confirmation. The ones most likely to harbor life would be smallish, rocky planets like Earth. Larger planets tend to be composed of hydrogen gas, the most abundant element in the universe, and to not have a solid surface. Good candidates for life would also occupy what scientists call the habitable zone—the zone in which a planet's distance from the parent star makes liquid water possible. The Kepler mission—a space observatory launched by NASA in 1997 to search our galaxy for just these kinds of Earth-like planets—has found one candidate that meets both requirements, Kepler-452b. So the chances of life on another planet are high. However, we have no direct evidence yet of life anywhere other than Earth. The real question is, will we ever find the planet we're looking for, given that we'll have to survey the planetary systems of the universe's estimated 1 billion trillion stars? And if we do find that planet, will we even recognize the life it harbors? There's no real reason why we should expect to discover life as we know it orbiting a star many light years away from our home solar system. There's so much we don't know that we are severely limited in our ability to even think about the question. Explore further: Just 40 light years from Earth, three planets might host life forms adapted to infrared worlds
If you’re anything like me, you’re probably curious about how your computer runs the programs you use every day. Here’s a quick rundown of the steps your CPU takes to run a program, courtesy of your friendly neighborhood blog writer. - The program is loaded into memory from storage. - The CPU fetches instructions from memory and decodes them. - The CPU executes the instructions and produces results. - The results are stored in memory or output to the user. So there you have it! That’s how your computer runs a program, in a nutshell. Thanks for reading and feel free to leave any questions or comments below! Each instruction has two parts: opcode and operand The instruction set is the basic, built-in commands that your CPU can understand and execute. Every program you run on your computer consists of a series of these instructions. The two parts of an instruction are the opcode (operation code) and the operand (usually either a number or an address). The opcode tells the CPU what operation to perform, while the operand tells it which data to perform that operation. In a simple pipelined CPU, each instruction goes through four stages: - Fetch: The instruction is fetched from memory. - Decode: The instruction is decoded, and the operands are read from registers. - Execute: The instruction is executed. - Writeback: The result is written back to memory (if needed). The opcode is a set of instructions that tells the CPU what to do. It is the first step in the process of running a program. The opcode is followed by one or more operands, which are the data that the instruction uses. The most common opcodes are: - Load: Loads data from memory into a register - Store: Stores data from a register into memory - Add: Adds two values and stores the result in a register - Subtract: Subtracts two values and stores the result in a register - Multiply: Multiplies two values and stores the result in a register - Divide: Divides two values and stores the result in a register In order to run a program, the CPU must be able to understand the instructions written in that program. The language that these instructions are written in is called instruction set. An operand is an entity on which the operation is carried out by the instruction. For example, in the instruction ADD A, B; A and B are operands. The instruction set of CPU consists of a number of operations like data transfer, arithmetic, logic etc. Each operation requires certain number of operands to be specified along with it. Data transfer operations require two operands – one for source and one for destination. Arithmetic and logic operations require two or three operands depending on the nature of operation 1) one-byte instructions The 8086 can fetch and execute a one-byte instruction in a single clock cycle. The machine language instructions of the 8086 are all one byte long and are encoded using a special encoding scheme. This opcode byte is followed by from 0 to 3 bytes of operands. Thus, the total length of an instruction is 1 to 4 bytes. a) two-byte instructions The 8086 can also fetch and execute certain two-byte instructions in a single clock cycle. These instructions are called jump (JMP), call (CALL), and return (RET). b) Instructions with longer encodings Apart from the one-byte and two-byte instructions, there are a number of other instructions whose machine language encodings are 3 or 4 bytes long. However, the fetch and execution of such instructions take more than one clock cycle. 2) Two‐byte instructions These instructions are 2‐bytes long and have an opcode followed by an operand. The operand can be either an 8‐bit immediate value or a 16‐bit memory address. The opcodes for two‐byte instructions start from 0x01. For example, the following instruction will move the value 0x12 to accumulator. MVI A, 0x12 The complete instruction set for two ‐ byte instructions is given below. Note that some instructions have different opcodes for register operands and memory operands. \|Opcode (in hex)\|Instruction\| \|04\|MOV E,data \|\| 05 MOV H,data \| 06 MOV L,data \| 07 MOV M,data \| 08 MOV A,data \| 3) Three‐byte instructions: In some cases, the instruction may be three bytes long. This is necessary when there is not a single register that can hold all of the data required by the instruction. For example, an instruction might require two registers and a memory location. In this case, the first byte would identify which operation to perform, and the next two bytes would identify the operands. Today, the most common type of CPU is the CISC (Complex Instruction Set Computer). CISC processors have a large number of operations that they can perform; this makes them more flexible and powerful than RISC processors. However, this increased flexibility means that CISC processors are more difficult to design, build, and program. In computer engineering, RISC (pronounced /rɪsk/), or reduced instruction set computing, is a type of CPU architecture that generally has fewer and simpler instructions than those in a complex instruction set computing (CISC) design. RISC architectures were evolved in an attempt to improve performance through the simplification of the processor instruction set, while complex instruction set architectures were designed with a focus on programming efficiency. These two approaches represent a continuous spectrum of designs, not two distinct classes. The precise definition of “RISC” varies somewhat among uses; however, all share some common characteristics such as supporting few addressing modes and directions for data movement; wide use of register files; simple instructions which require one clock cycle to complete; fixed-width instructions; and separate code and data spaces. The term “RISC” was coined by David Patterson and John Hennessy (co-authors of a well-known textbook on computer architecture) at Berkeley. They wrote: Reduced Instruction Set Computing (RISC) is a type of microprocessor architecture that utilizes a small, highly optimized set of instructions, rather than a more specialized or complex set of instructions often found in other types of architectures. The processing of an instruction by the CPU comprises the following steps: - Fetching the instruction from memory - Decoding the instruction - Executing the instruction - Storing the results back in memory The first step, fetch, involves the retrieval of an instruction from memory. The instruction is placed into the instruction register (IR). The addresses of the operands (if any) are also fetched and placed into memory address register(s) (MAR). The instruction set is specific to a class of processors. instructions are stored as binary values, in the form of opcodes, that the CPU reads and interprets. When the CPU decodes an opcode, it uses the operands to determine what actions to take. In some cases, the operand is a memory address or a value that is stored in memory. The operand tells the CPU where to find data or where to store data. The very first thing that a CPU does when it is turned on is to execute a bootstrap program stored in ROM. The purpose of this program is to initialize the CPU and its associated hardware, and to load and start an operating system. Once the CPU has finished executing the bootstrap program, it enters an idle loop, waiting for an interrupt. When an interrupt occurs, the CPU fetches and executes the next instruction from memory. If the instruction is a branch or jump instruction, the CPU will fetch and execute instructions from a different memory location. Otherwise, it will simply fetch and execute the next instruction in sequence. When a program is written in a high-level language, it needs to be translated into machine code that the CPU can understand. This process is called compiling. Once the program has been compiled, it can be stored in memory until it is needed. Now that you understand the steps taken by the CPU to run a program, you can see how important it is to choose the right instruction set for your needs. RISC architectures are designed for performance, while CISC architectures are designed for programming efficiency. Choose the architecture that best meets your needs. Thank you for reading!
1612 The French explorer Etienne Brule is believed to be the first European to see the Great Lakes. Brule, believed to have been born in 1592, journeyed to North America with Samuel de Champlain in 1608 and helped found Quebec. Brule explored Lake Huron in 1612 and is believed to have also explored Lakes Ontario, Erie and Superior after 1615. Brule is the first European to live among the Indians and was probably the first European to set foot in what is now Pennsylvania. Brule was eventually killed by the Hurons, for reasons never known, in 1632. 1643 Tinicum township, founded by Swedes, was the first European settlement in Pennsylvania. 1644 Oct 14, William Penn, founder of Pennsylvania, or Penn's Woods, was born. 1681 Mar 4, England's King Charles II granted a charter to William Penn (37) for 48,000 square miles that later became Pennsylvania. Penn’s father had bequeathed him a claim of £15,000 against the king. Penn later laid out the city of Philadelphia as a gridiron about 2 miles long, east to west, and a mile wide. (PCh, 1992, p.259)(AP, 3/4/98)(SFEC, 8/16/98, 1682 Oct 26, William Penn accepted the area around the Delaware River from Duke of York. 1682 Oct 29, The founder of Pennsylvania, William Penn, landed at what is now Chester, Pa. William Penn founded Philadelphia. Penn founded Pennsylvania as a "Holy Experiment" based on Quaker principles. (AP, 10/29/97)(SFEC, 6/21/98, Z1 p.8)(SSFC, 1682 William Penn established Bucks County as one of Pennsylvania’s 3 original counties. (WSJ, 3/22/08, p.R7) 1683 Jun 23, William Penn signed a friendship treaty with Lenni Lenape Indians in Pennsylvania. It became the only treaty "not sworn to, nor broken." (HN, 6/23/98)(MC, 6/23/02) 1683 Oct 6, 13 Mennonite families from Krefeld, Germany, arrived in present-day Philadelphia to begin Germantown, one of America's oldest settlements. They were encouraged by William Penn's offer of 5,000 acres of land in the colony of Pennsylvania and the freedom to practice their religion. 1686 The Lenape Indians allegedly sold land along the Lehigh River to William Penn. (ON, 1/03, p.6) 1687 William Penn authored “The Excellent Privilege of Liberty and Property Being the Birth-Right of the Free-born subjects of England." 1688 Feb 18, At a Quaker meeting in Germantown, Pa, German Mennonites penned a memorandum stating a profound opposition to Negro slavery. Quakers in Germantown, Pa., adopted the fist formal antislavery resolution in 1692 Mar 18, William Penn was deprived of his governing powers. 1699 Jonathan Dickinson, after resuming his mercantile business in Philadelphia, authored "God’s Protecting Providence," a journal of his Florida ordeal. (ON, 9/00, p.5) 1700 May 7, William Penn began monthly meetings for Blacks advocating emancipation. 1701 Oct 28, William Penn presented a Charter of Privileges for the Province of Pennsylvania during his 2nd and last visit to the colony. Among its provisions was one establishing total religious freedom and tolerance to those who wanted to live in peace in the colony. It remained as Pennsylvania's constitution until the outbreak of the American Revolution 1712 Jun 7, The Pennsylvania Assembly banned the importation of slaves. 1718 Jul 30, William Penn, English Quaker, colonizer (No cross, no crown), died. 1720s The Ephrata Cloister communal society in Amish country near Philadelphia was founded by a former elder of the German Dunkers (German Baptists who later became the Church of the 1722 Quaker Jonathan Dickinson died. He had become one of the wealthiest men in the city and served as twice as mayor. (ON, 9/00, p.5) 1726 Jul 23, Benjamin Franklin sailed back to Philadelphia. 1726 Oct 11, Benjamin Franklin returned to Philadelphia from England. 1730 Benjamin Franklin became the official printer for Pennsylvania. He ultimately became the official printer for several colonial governments. (AH, 2/06, p.48) 1730s German gun makers located in Pennsylvania began producing the Kentucky rifle, so named because it was intended for use on the Kentucky frontier. Its gunpowder was ignited with sparks struck when the hammer, containing a piece of flint, was released. The flintlock Kentucky rifle, with its extra long barrel and small caliber, was the most accurate rifle of its day and was used widely in the French and Indian Wars and American Revolution. 1731 Jul 1, The “Instrument of Association" for the Library Company of Philadelphia was signed under the leadership of Benjamin Franklin. It was America’s first 1732 Feb 26, The 1st mass celebrated in American Catholic church was at St Joseph's Church, 1732 Nov 14, 1st US professional librarian, Louis Timothee, was hired in Phila. 1732 Dec 28, The first Poor Richard's Almanac was published along with the 1st known ad in the Pennsylvania Gazette. The Almanack was published by Richard Saunders (really Ben Franklin). [see Dec 19] (HFA, '96, p.20)(MC, 12/28/01) 1733 The Pennsylvania city of Reading became one of America's first producers of iron and was for nearly a century the foremost in the country. Settled in 1733 by the sons of William Penn, the city is situated on the Schuylkill River in the southeastern part of the state. The Reading foundries furnished cannon for the American forces in the Revolutionary War and the Union during the Civil War. 1738 Benjamin Franklin wrote in Poor Richard's Almanack "Sell not virtue to purchase wealth, nor Liberty to purchase power." 1740 Sep 11, The first mention of an African American doctor or dentist in the colonies was made in the Pennsylvania Gazette. 1741 Feb 13, Andrew Bradford of Pennsylvania published the first American magazine. Titled "The American Magazine, or A Monthly View of the Political State of the British Colonies." Bradford introduced his American Magazine just days before Benjamin Franklin founded his periodical called General Magazine in Philadelphia. Bradford’s survived 3 months while Franklin’s survived for 6 months. (HFA, '96, p.24)(HNQ, 9/3/98)(AP, 2/13/01) 1741 Feb 16, Benjamin Franklin's General Magazine (2nd US Mag) began publishing. 1743 Benjamin Franklin and John Bartram founded the American Philosophical Society in Philadelphia as an American counterpart to the British Royal Society. 1745 Dec 24, Benjamin Rush, American medical pioneer and signer of the Declaration of Independence, was born in Byberry, Pa. (HN, 12/24/98)(MC, 12/24/01) 1746 Linden Hall, a girls’ boarding school, opened in Lititz, Pa. (SSFC, 4/13/03, p.D6) 1750 Benjamin Franklin drew up plans for a “sentry box," designed to prove his theory that lightning as an electrical phenomenon. (ON, 2/12, p.11) 1750 Teedyuscung, a Lenape Indian, joined the Christian mission of Gnadenhutten, founded by Swiss Moravian settlers in the Lehigh Valley town of Bethlehem. (ON, 1/03, p.6) 1751 May 11, The 1st US hospital was founded in Pennsylvania. [see Feb 11, 1752] 1752 Jan 1, Betsy Ross (d.1836), flag maker who contributed to the design of the American flag, was born in Philadelphia as Elizabeth Griscom. 1752 Feb 11, Pennsylvania Hospital, the 1st hospital in the US, opened. 1752 May 11, The 1st US fire insurance policy issued in Philadelphia. 1752 May, Dutch botanist Thomas Francois Dalibard (1709-1799) successfully performed Benjamin Franklin’s “sentry box" experiment proving that lightning is an 1752 Jun 15, Benjamin Franklin and his son tested the relationship between electricity and lightning by flying a kite in a thunder storm. Some sources date this to June 10. 1752 Sep 1, The Liberty Bell arrived in Philadelphia. 1752 In the summer of this year Benjamin Franklin installed the world’s 1st lightning rods at the Pennsylvania State House. (WSJ, 8/15/05, p.D8) 1753 Dec 12, George Washington, the adjutant of Virginia, delivered an ultimatum to the French forces at Fort Le Boeuf, south of Lake Erie, reiterating Britain’s claim to the entire Ohio river valley. 1753 Dec 14, French Captain Jacques Le Gardeur rejected the pretensions of the English to ownership of the Ohio Valley, but promised to forward Virginia Gov. Dinwiddie’s letter of trespass to his superiors in Canada. (ON, 9/05, p.2) 1753 The Georgian-style colonial legislature (later Pennsylvania State House) was completed at 520 Chestnut St. in Philadelphia for the Province of Pennsylvania. It became the location where both the Declaration of Independence and the United States Constitution were debated and adopted and thus became known as Independence Hall. (SSFC, 5/25/14, p.P5) 1753 Benjamin Franklin use the pages of his Poor Richard’s Almanac to make a case for using lightning rods atop tall structures making storms less dangerous. (WSJ, 8/15/05, p.D8) 1754 Jan 6, Major George Washington, while returning to Virginia, encountered a party of English settlers and militiamen at Will’s Creek sent by Gov. Dinwiddie to establish a fort and trading post at the Forks of the (ON, 9/05, p.2) 1754 Apr 2, A small expeditionary force of 159 men under Lt. Col. George Washington arrived at Will’s Creek and learned that the French had taken over the new Fort Prince George at the Forks of the Ohio from British soldiers and frontiersmen and renamed it Fort Duquesne. (ON, 9/05, p.2) 1754 Apr, Teedyuscung, a Lenape Indian, joined the Iraquois Indians in the Wyoming Valley along the banks of the Susquehanna River. (ON, 1/03, p.6) 1754 May 9, The first American newspaper cartoon was published. The illustration in Benjamin Franklin's Pennsylvania Gazette showed a snake cut into sections, each part representing an American colony; the caption read, "Join (AP, 5/9/97)(HN, 5/9/98) 1754 May 28, Col. George Washington led a 40-man detachment that defeated French and Indian forces in a skirmish near Great Meadows, Pa. (ON, 9/05, p.3) 1754 Jun 19, The Albany Congress opened. New York colonial Gov. George Clinton called for the meeting to discuss better relations with Indian tribes and common defensive measures against the French. The attendees included Indians and representatives from Connecticut, Maryland, Massachusetts, New Hampshire, New York, Pennsylvania and Rhode Island. Benjamin Franklin attended and presented his Plan of Union, which was adopted by the conference. The meeting ended on July 11. 1754 Jul 3, George Washington surrendered the small, circular Fort Necessity (later Pittsburgh) in southwestern Pennsylvania to the French, leaving them in control of the Ohio Valley. This marked the beginning of the French and Indian War also called the 7 Years' War. In 2005 Fred Anderson authored “The War That Made America: A Short History of the French and Indian (HN, 7/13/98)(Arch, 1/05, p.46)(WSJ, 12/14/05, 1754 Nov 29, The Gnadenhutten mission, Pa., was attacked by renegade Lenape Indians and 11 white people were killed. (ON, 1/03, p.7) 1755 Jul 9, General Edward Braddock was mortally wounded when French and Indian troops ambushed his force of British regulars and colonial militia, which was on its way to attack France's Fort Duquesne (Pittsburgh). Gen. Braddock's troops were decimated at Fort Duquesne, where he refused to accept Washington's advice on frontier style fighting. British Gen'l. Braddock gave his bloody sash to George Washington at Fort Necessity just before he died on Jul 13. (A & IP, ESM, p.11)(HN, 7/9/98)(WSJ, 1/5/98, 1755 Jul 13, Edward Braddock (60), British general, died following the July 9, 1755 battle at Fort Duquesne (Pittsburgh, Pennsylvania). Out of the 1,400 British soldiers who were in involved in the battle, 900 of them died. Future President George Washington carried Braddock from the field and officiated at his burial ceremony. The general was buried in a road his men had built. The army then marched over the grave to obliterate any traces of it and continued to eastern Pennsylvania. After the French and Indian War (1754-1763), the Braddock Road remained a main road. In 1804, some workmen discovered human remains in the road near where Braddock was supposed to have been buried. The remains were re-interred on a small knoll adjacent to the road. In 1913 the marker was placed there. Braddock was born in Perthshire, Scotland, about 1695, the son of Major-General Edward Braddock (died 1725). 1755 Dec 31, Teedyuscung, a Lenape Indian, led 30 Lenape Indians on a raid against English plantations along the Delaware River. Over the next few days his band killed 7 men and took 5 prisoners. (ON, 1/03, p.6) 1755 Benjamin Franklin, a patriot of the American Revolution, served as a colonel of the Pennsylvania militia in the French and Indian War. Benjamin Franklin, at forty-nine, had already lived through two wars between the French and the English and their colonists. His face was puffy and smooth from gout, his once-powerful swimmer’s body overweight and rounded into a barrel shape. 1756 Jun 4, Quakers left the assembly of Pennsylvania. 1756 Nov 12, Teedyuscung, a Lenape Indian, spoke with Gov. Denny at Easton, Pa., to discuss (ON, 1/03, p.6) 1756 German-speaking Moravians founded the town of Lititz, 35 miles southeast of Harrisburg, Pa. Non-Moravians were not allowed to live there until 1855. (SSFC, 4/13/03, p.D6) 1757 Benjamin Franklin (1706-1790) helped set up America’s first street cleaning service in (Econ, 2/28/09, SR p.5) 1757 Benjamin Franklin sailed for England. He spent almost two decades there as colonial agent, a combination lobbyist, ambassador, and banker, for Pennsylvania and, eventually Georgia, New Jersey and Massachusetts. He lived in London at 36 Craven St. (WSJ, 8/8/95, p. A12)(USAT, 9/22/03, p.16A) 1758 Nov 25, In the French and Indian War British forces under General John Forbes captured Fort Duquesne (the site of present day Pittsburgh, est. 1754). George Washington participated in the campaign. Forbes renamed the site Fort Pitt after William Pitt the Elder, who directed British military policy in the Seven Years' War of 1756-'63. Before his arrival, the French had burned the fort and retreated. (AP, 11/25/97)(ON, 9/05, p.5)(HNQ, 7/17/98) 1758 Feb 15, The 1st mustard manufactured in America was advertised in Philadelphia. (440 Int’l., 2/15/99)(HCB, 2003, p. 94) 1760 Feb 14, Richard Allen (d.1831), 1st black ordained by a Methodist-Episcopal church, was born in Philadelphia. 1760s-1770s John Cadwalader, Revolutionary War General, commissioned dozens of furniture pieces from the finest craftsmen in Pennsylvania. He had married Elizabeth Lloyd, the wealthiest woman in colonial America. (WSJ, 9/24/99, p.W9) 1761 French and Indians forces in the Ohio Valley were defeated. (ON, 1/03, p.7) 1762 Benjamin Franklin returned to Philadelphia from London and remained until 1764. 1763 Apr 19, Teedyuscung, a Lenape Indian leader, burned to death while sleeping in his cabin in the Wyoming Valley, Pa. The fire destroyed the whole Indian village. A few days later settlers from Connecticut arrived to resume their construction of a town. (ON, 1/03, p.6) 1763 May 7, Indian chief Pontiac began his attack on a British fort in present-day Detroit, Michigan. Ottawa Chief Pontiac led an uprising in the wild, distant lands that later became Michigan, Ohio and Pennsylvania. (HN, 7/24/98)(HN, 5/7/99) 1763 Aug 5, Colonel Henry Bouquet decisively defeated the Indians at the Battle of Bushy Run in Pennsylvania during Pontiac's rebellion. 1763 Nov 15, Charles Mason and Jeremiah Dixon began surveying Mason-Dixon Line between Pennsylvania and Maryland. They surveyed 233 miles by 1767 when Indians of the Six nations told them they could not proceed any further west. (MC, 11/15/01)(ON, 2/04, p.10) 1767 Oct 9, The survey party of Mason and Dixon came to a halt after 233 miles when Indians of the Six Nations said they had reached the end of their commission. [see (ON, 2/04, p.10) 1767 Oct 18, The boundary between Maryland and Pennsylvania, the Mason-Dixon line, was agreed upon. It was first surveyed in 1763 to 1767 by two British astronomers, Charles Mason and Jeremiah Dixon, in order to settle a dispute between the Calvert and Penn families, the owners at that time of the two states in question. The survey, begun in 1763 and completed four years later, done by English surveyors Charles Mason and Jeremiah Dixon to resolve a land-grant boundary dispute between the families of Lord Baltimore and William Penn, resulted in the Mason-Dixon Line. The line, extended in 1784, came to be known as the dividing line between free-soil states and slave states. (AP, 10/18/97)(HNQ, 9/8/99) 1771 Jun 12, Patrick Gass, Sgt. of Lewis & Clark Expedition, was born in Falling Springs, PA. 1773 Feb 26, Construction was authorized for Walnut St. jail in Philadelphia, (1st solitary). 1773 Dec 26, Expulsion of tea ships from Philadelphia. 1774 Jul 12, Citizens of Carlisle, Penn., passed a declaration of independence. 1774 Sep 5, The first Continental Congress assembled in Philadelphia in a secret session in Carpenter's Hall with representatives from every colony except Georgia. Tensions had been tearing at relations between the colonists and the government of King George III. The British taking singular exception to the 1773 shipboard tea party held in Boston harbor. The dispute convinced Britain to pass the "Intolerable Acts"- 4 of which were to punish Mass. for the Boston Tea Party. Peyton Randolph of Williamsburg, Va., chaired the 1st Continental Congress. Its first official act was a call to prayer. (AP, 9/5/97)(HNQ, 6/25/00)(AH, 10/04, p.14)(AH, 1774 Sep 26, John Chapman (d.1845), later known as Johnny Appleseed, was born in Massachusetts. A pioneer agriculturalist of early America, Chapman began his trek in 1797, collecting apple seedlings from western Pennsylvania and establishing apple nurseries around the early American frontier. Chapman was a Swedenborgian missionary, a land speculator, a heavy drinker and an eccentric dresser (he hated shoes and seldom wore them. He planted orchards across western Pennsylvania, Ohio, and Indiana from seed. p.42)(HNQ, 9/4/01)(ON, 4/09, p.10) 1774 Oct 26, The first Continental Congress, which protested British measures and called for civil disobedience, concluded in Philadelphia. The Congress had met at the Philadelphia Carpenter's Hall. (AP, 10/26/97)(HN, 10/26/98)(SFEC, 2/20/00, Z1 1774 Nov, Thomas Paine, English pamphleteer, arrived in Philadelphia. He had been urged to come to America by Ben Franklin. (ON, 6/2011, p.1) 1775 Feb, Englishman Thomas Paine became editor of the Pennsylvania Magazine, owned by printer (ON, 6/2011, p.1) 1775 Apr 13, Lord North extended the New England Restraining Act to South Carolina, Virginia, Pennsylvania, New Jersey and Maryland. The act forbade trade with any country other than Britain and Ireland. 1775 Apr 14, The first American society for the abolition of slavery was organized by Benjamin Franklin and Benjamin Rush in Philadelphia. (AP, 4/14/97) (HN, 4/14/98) 1775 May 5, Benjamin Franklin arrived in Philadelphia, from London where he had lived since 1757. He soon began working with Thomas Paine on a pamphlet urging independence from Britain, an idea proposed by physician Benjamin (AH, 2/06, p.52)(ON, 6/2011, p.2) 1775 May 10, The Second Continental Congress convened in Pennsylvania. It named George Washington as supreme commander. Benjamin Franklin represented Pennsylvania soon presented his reworked Plan of Union under the title The Articles of Confederation and Perpetual Union. 1775 Jul 26, The Continental Congress established a postal system for the colonies with Benjamin Franklin as the first postmaster general in Philadelphia. (AP, 7/26/97)(HN, 7/26/98) 1775 Nov 10, The US Continental Marines were organized under authority of the Continental Congress. Congress commissioned Samuel Nicholas to raise two Battalions of Marines. That very day, Nicholas set up shop in Philadelphia’s Tun Tavern. He appointed Robert Mullan, then the proprietor of the tavern, to the job of chief Marine Recruiter serving, of course, from his place of business at Tun Tavern. The naval infantry later became the US Marine Corps. 1776 Jul 4, The Continental Congress approved adoption of the amended Declaration of Independence, prepared by Thomas Jefferson and signed by John Hancock--President of the Continental Congress--and Charles Thomson, Congress secretary, without dissent. However, the New York delegation abstained as directed by the New York Provisional Congress. On July 9, the New York Congress voted to endorse the declaration. On July 19, Congress then resolved to have the "Unanimous Declaration" inscribed on parchment for the signature of the delegates. Among the signers of the Declaration of Independence, two went on to become presidents of the United States, John Adams and Thomas Jefferson. The Declaration of Independence was signed by president of Congress John Hancock and secretary Charles Thomson. John Hancock said, "There, I guess King George will be able to read that." referring to his signature on the Declaration of Independence. Most delegates signed the parchment copy on August 2. Other signers later included Benjamin Rush and Robert Morris. Of the 56 signers of the Declaration of Independence, eight were born outside North America. In 2007 David Armitage authored “The Declaration of Independence: A Global History." 1/4/07, p.B11)(SFC, 7/4/13, p.A14) 1776 Jul 5, The Declaration of Independence was first printed by John Dunlop in Philadelphia. 200 copies were prepared July 5-6 and distributed to the states. (HN, 7/5/98)(HNQ, 7/4/99)(SFC, 7/4/01, p.A3) 1776 Jul 6, The US Declaration of Independence was announced on the front page of "PA Evening 1776 Jul 8, Col. John Nixon gave the first public reading of the Declaration of Independence to a crowd gathered at Independence Square in Philadelphia. The reading was announced by the "Liberty Bell." The bell had the inscription: "proclaim liberty throughout all the land onto all the inhabitants (AP, 7/8/97)(SFEC, 8/16/98, p.T5) 1776 Aug 2, In Philadelphia most members of the Continental Congress began attaching their signatures to the parchment copy of the Declaration of Independence. Benjamin Harrison was one of the signers. His son and grandson later became the 9th and 23rd presidents of the US. Most of the 55 signatures were affixed on August 2, but Matthew Thornton of New Hampshire, who was not a member of Congress when the declaration was adopted, added his name in November. (Civil., Jul-Aug., '95, p.61)(SFC, 5/7/96, p.A-6)(AP, 8/2/97)(HNQ, 7/4/99) 1775 Dec 18-1775 Dec 27, In Philadelphia Benjamin Franklin, John Jay and Francis Daymon, members of the Committee of Secret Correspondence, met 3 times at Carpenter’s Hall with French agent Chevalier Julien-Alexandre Achard de Bonvouloir regarding French support for American Independence. (AH, 2/06, p.58) 1775 Nov 10, The US Marines were organized under authority of the Continental Congress. Congress commissioned Samuel Nicholas to raise two Battalions of Marines. That very day, Nicholas set up shop in Philadelphia’s Tun Tavern. He appointed Robert Mullan, then the proprietor of the tavern, to the job of chief Marine Recruiter serving, of course, from his place of business at Tun Tavern. 1776 Jan 10, Thomas Paine (1737-1809), British émigré and propagandist, anonymously published "Common Sense," a scathing attack on King George III's reign over the colonies and a call for complete independence. The first 1,000 sold within days at 2 shillings. By the end of the year some 150,000 copies were sold, greatly affecting public sentiment and the deliberations of the Continental Congress leading up to the Declaration of Independence. An instant bestseller in both the colonies and in Britain, Paine baldly stated that King George III was a tyrant and that Americans should shed any sentimental attachment to the monarchy. America, he argued, had a moral obligation to reject monarchy. 1/10/98)(ON, 6/2011, p.3) 1776 Mar 2, The American Secret Committee of Correspondence appointed Connecticut lawyer Silas Deane as a special envoy to negotiate with the French government for aid. (AH, 2/06, p.59) 1776 Dec 2, George Washington's army began retreating across the Delaware River from New Jersey to Pennsylvania. In 2004 David Hackett Fischer authored "Washington's (WSJ, 2/6/04, p.W8) 1776 Dec 8, George Washington's retreating army in the American Revolution crossed the Delaware River from New Jersey to Pennsylvania. 1776 Dec 23, Thomas Paine’s pamphlet, “The American Crisis," which included the line "These are the times that try men's souls…" was read out loud by George Washington to the Continental Army. (ON, 6/2011, p.4) 1776 Dec 25, Gen. George Washington and his troops crossed the Delaware River for a surprise attack against Hessian forces at Trenton, N.J. 1776 The Quakers of Pennsylvania abolished slavery within the Society of Friends and then took their crusade to society at large by petitioning the state legislature to outlaw the practice. (AH, 10/02, p.50) 1777 Jun 14, The Continental Congress in Philadelphia adopted the Stars and Stripes as the national flag. America's Flag Day, commemorates the date when John Adams spoke the following words before the Continental Congress in Philadelphia. "Resolved, that the Flag of the thirteen United States shall be thirteen stripes, alternate red and white; that the Union be thirteen stars, white on a blue field, representing a new constellation." Over the years, there have been 27 versions of the American flag. The present version was adopted on July 4, 1960, when Hawaii became the 50th state. (AP, 6/14/97)(HNQ, 6/14/98) 1777 Jul 4, No member of Congress thought about commemorating the adoption of the Declaration of Independence until July 3 - one day too late. So the first organized elaborate celebration of independence occurred the following day: July 4, 1777, in Philadelphia. 1777 Sep 11, General George Washington and his troops were defeated by the British under General Sir William Howe at the Battle of Brandywine in Pennsylvania. Posing as a gunsmith, British Sergeant John Howe served as General Gage's eyes in a restive Massachusetts colony. 1777 Sep 20, British Dragoons massacred sleeping Continental troops at Paoli, Pa. 1777 Sep 26, The British army launched a major offensive during the American Revolution, capturing 1777 Sep 30, The Congress of the United States, forced to flee in the face of advancing British forces, moved to York, Pennsylvania. 1777 Oct 4, George Washington's troops launched an assault on the British at Germantown, Penn., resulting in heavy American casualties. British General Sir William Howe repelled Washington's last attempt to retake Philadelphia, compelling Washington to spend the winter at Valley Forge. (AP, 10/4/97)(HN, 10/4/98) 1777 Nov 15, The Continental Congress adopted the Articles of Confederation in York, Pa. These instituted the perpetual union of the United States of America and served as a precursor to the U.S. Constitution. The structure of the Constitution was inspired by the Iroquois Confederacy of six major northeastern tribes. The matrilineal society of the Iroquois later inspired the suffragist movement. (PCh, 1992, p.325)(AP, 11/15/97)(SFEC, 4/19/98, BR p.2)(HN, 11/15/98) 1777 Dec 2, British officers under Gen. Howe met in the Philadelphia home of Lydia Darragh to discuss plans to the attack American forces on December 5, just prior to Gen. Washington’s planned move to Valley Forge. Mrs. Darragh listened in on the plans and sent word to Whitemarsh of the (ON, 8/07, p.8) 1777 Dec 5, A British advance column met unexpected resistance at Germantown, Penn. Gen. Howe refrained from a direct attack on Whitemarsh, where Gen. Wasinington was based, and the battle dissolved in a series of inconclusive skirmishes that lasted 3 days. The Americans lost 90 men killed or wounded and the British lost 60. (ON, 8/07, p.8) 1777 Dec 8, Britain’s Gen. Howe withdrew to Philadelphia following a failed attempt on American forces encamped at Whitemarsh. (ON, 8/07, p.8) 1777 Dec 19, Gen. George Washington led his army of about 11,000 men to Valley Forge, Pa., to camp for the winter. [see Dec 17] 1777 George Washington led a campaign against the British and their Iroquois allies in Pennsylvania, New York, and the Ohio country. These included the Six Nations Indians: Mohawk, Cayuga, Onondaga, Seneca, Oneida, and Tuscarora. In 2005 Glenn F. Williams published “The Year of the Hangman: George Washington’s Campaign Against the Iroquois. (WSJ, 7/26/05, p.D8) 1777-1778 Some 2,000 American soldiers died at Washington’s Valley Forge encampment over a harsh weather period of (WSJ, 1/3/02, p.A7) 1778 Jun 18, American forces entered Philadelphia as the British withdrew during the (AP, 6/18/97)(HN, 6/18/98) 1778 Jun 19, General George Washington’s troops finally left Valley Forge after a winter of training. Washington left to intercept the British force on its way to New York City. (HN, 6/19/98)(MC, 6/20/02) 1778 Jun 27, The Liberty Bell came home to Philadelphia after the British left. 1778 Jun, George Washington appointed Benedict Arnold as military governor of Philadelphia. (ON, 11/01, p.1) 1778 Jul 3, The Wyoming Massacre occurred during the American Revolution in the Wyoming Valley of Pennsylvania. As part of a British campaign against settlers in the frontier during the war, 360 American settlers, including women and children, were killed at an outpost called Wintermoot's Fort after they were drawn out of the protection of the fort and ambushed. (HNQ, 11/5/98)(MC, 7/3/02) 1778 Sep 17, The 1st treaty between the US and Indian tribes was signed at Fort Pitt. 1779 May 23, Benedict Arnold, military governor of Philadelphia, wrote a query to the British asking what they would pay for his services. He had already begun trading with the British for personal profit and faced charges. (ON, 11/01, p.1) 1779 Dec 25, A court-martial was convened against Benedict Arnold. He defended himself successfully on 6 of 8 charges but was convicted of illegally issuing a government pass and using government wagons to transport (ON, 11/01, p.2) 1780 Mar 1, Pennsylvania became the first U.S. state to abolish slavery (for new-borns only). It was followed by Connecticut and Rhode Island in 1784, New York in 1785, and New Jersey in 1786. Massachusetts abolished slavery through a judicial decision in 1783 (see July 8 1777). 1780 Apr, George Washington censured Benedict Arnold for his misdeeds as governor of (ON, 11/01, p.2) 1782 Jan 7, The 1st US commercial bank, Bank of North America, opened in Philadelphia. 1782 Jun 20, Congress approved the Great Seal of the United States and the eagle as its symbol. (AP, 6/20/97)(MC, 6/20/02) 1783 May 30, The first American daily newspaper, The Pennsylvania Evening Post, began publishing in 1785 Jan 6, Haym Salomon (44) died in Philadelphia. He helped finance the US revolution. 1785 Mar 1, Philadelphia Society for the Promotion of Agriculture was organized. 1785 May 9, James Pollard Espy, meteorologist (Philosophy of Storms), was born in Pennsylvania. 1785 Oct 18, Benjamin Franklin was elected president of Pennsylvania. Special balloting unanimously elected Franklin the sixth President of the Supreme Executive Council of Pennsylvania, replacing John Dickinson. 1787 Apr 12, Philadelphia's Free African Society formed. 1787 May 25, The Constitutional Convention convened in Philadelphia after enough delegates showed up for a quorum. The Founding Fathers turned to the Rushworth's Collections of England for revolutionary precedents. George Washington presided. [see May 25, 1777] Rhode Island refused to send (AP, 5/25/97)(WSJ, 3/10/99, p.A22)(HN, 5/25/99)(Econ, 9/16/06, p.44) 1787 Aug 6, The Constitutional Convention in Philadelphia began to debate the articles contained in a draft of the United States Constitution. 1787 Sep 17, The Constitution of the United States was completed and signed by a majority of delegates (12) attending the constitutional convention in Philadelphia. The US Constitution went into effect on Mar 4, 1789. Clause 3 of Article I, Section 8 empowered Congress to "regulate Commerce with foreign nations, among the several states, and with the Indian Tribes." Two of the signers went on to become presidents of the United States. George Washington, the president of the Constitutional Convention, and James Madison both signed the Constitution. The US Constitution is the world's oldest working Constitution. George Mason of Virginia refused to sign the document because he thought it made the federal government too powerful believed that it should contain a Bill of Rights. (AP, 9/17/97)(WUD, 1994, p.314)(WSJ, 4/9/99, p.W17)(HNQ, 5/19/99)(WSJ, 3/31/06, p.A1) 1787 Sep 17, The US Constitution included the Connecticut, or "Great," Compromise in which every state was conceded an equal vote in the Senate irrespective of its size, but representation in the House was to be on the basis of the "federal ratio," an enumeration of the free population plus three fifths of the slaves. The convention decided that ratification by nine states would be sufficient for their document to replace the 1777 Articles of Confederation. (SSFC, 11/2/03, p.M6)(Economist, 9/30/17, p.23) 1787 Sep 17, The "College of Electors" (electoral college) was established at the Constitutional Convention with representatives to be chosen by the states. Pierce Butler of South Carolina first proposed the electoral college system. [see Sep 13, 1788] (SFC, 11/9/00, p.A14)(WSJ, 11/9/00, p.A26) 1787 Sep 17, The Electoral College, proposed by James Wilson, was the compromise that the Constitutional Convention reached. In 2004 George C. Edwards III authored “Why the Electoral College Is Bad for America." 1787 Dec 10, Thomas H. Gallaudet, a pioneer of educating the deaf, was born in 1787 Dec 12, Pennsylvania became the second state to ratify the U.S. Constitution. 1787 Peter Markoe (1752?-1792) authored “An Algerine Spy in Pennsylvania." His satirical provocation helped to push the US Congress authorized a Navy and to dispatch Marines to subdue the pirates of Tripoli. (WSJ, 6/2/07, p.P8) 1787 Rev. Richard Allen and Absalom Jones decided to form the Free African Society, a non-denominational religious mutual aid society for the black community. Eventually this society grew into the African Church of 1789 Mar 2, Pennsylvania ended the prohibition of theatrical performances. 1789 Dec 28, Lydia Darrragh (b.1729), American spy, died in Philadelphia. Her exploits in 1777 did not become public until the publication of an anonymous article 1790 Mar 1, President Washington signed a measure authorizing the first US Census. The Connecticut Compromise was a proposal for two houses in the legislature-one based on equal representation for each state, the other for population-based representation-that resolved the dispute between large and small states at the Constitutional Convention. Connecticut delegate Roger Sherman's proposal led to the first nationwide census in 1790. The population was determined to be 3,929,625, which included 697,624 slaves and 59,557 free blacks. The most populous state was Virginia, with 747,610 people and the most populous city was Philadelphia with 42,444 inhabitants. The average cost of this year’s census was 1.13 cents per person. 1790 Apr 17, Benjamin Franklin (born 1706), American statesman, died in Philadelphia at age 84. He mechanized the process of making sounds from tuned glass with his glass armonica. In 2000 H.W. Brands authored his Franklin biography: "The First American." In 2003 Walter Isaacson authored "Benjamin Franklin: An American Life." (AP, 4/17/97)(SFEC,12/28/97, DB p.17)(WSJ, 9/20/00, p.A24)(WSJ, 7/3/03, p.D8) 1790 Jun 9, The "Philadelphia Spelling Book" was the first US work to be copyrighted. (WSJ, 6/14/00, p.A1)(MC, 6/9/02) 1790 Aug 2, The enumeration for the first US census began. It showed that 3,929,326 people were living in the US of which 697,681 were slaves, and that the largest cities were New York City with 33,000 inhabitants; Philadelphia, with 28,000; Boston, with 18,000; Charleston, South Carolina, with 16,000; and Baltimore, with 13,000. Census records for Delaware, Georgia, New Jersey, and Virginia were lost sometime between 1790 1790 Dec 6, Congress moved from New York City to Philadelphia, where Washington served out his two terms. He is the only president who never resided in the White (AP, 12/6/97)(HNPD, 12/22/98) 1791 Mar 11, Samuel Mulliken of Philadelphia was the 1st to obtain more than 1 US patent. 1791 Apr 23, James Buchanan, was born in Franklin County, Pa. He was the fifteenth U.S. president (1857-1861) and the only president not to marry. (AP, 4/23/97)(HN, 4/23/99) 1791 Jul 25, Free African Society (FAS) leaders drew up a plan to organize a church for 1791 William Sprague opened the 1st US carpet mill in Philadelphia. (SFCM, 10/10/04, p.8) 1793 Jan 9, The first US manned balloon flight occurred as Frenchman Jean Pierre Blanchard, using a hot-air balloon, flew between Philadelphia and Woodbury, N.J. He stayed airborne for 46 minutes, traveled close to 15 miles and set down at the "old Clement farm" in Deptford, New Jersey. [see Jun 23, 1784, Mar 9, 1793] (WSJ, 3/31/98, p.A1)(AP, 1/9/99)(ON, 6/09, p.2) 1793 Jun 20, Eli Whitney petitioned for a cotton gin patent in Philadelphia. 1793 The 1st US half-cent and one cent coins were minted in Philadelphia. For almost 6 decades the obverse side carried an image of Lady Liberty. The first coins were related to the silver dollar. The half-dollar contained half as much silver, the quarter had one-fourth as much. The dime had a 10th and the half dime has a 20th as much silver as the dollar. Only the penny was made of copper. In 1866 the Mint decided to produce a larger five-cent coin. In 2012 a one-cent copper coin minted this year fetched $1 million at a Florida auction. By 2018 only about 500 pennies were left in existence and one put up for auction was valued at $300,000. (SFC, 9/11/96, p.A4)(WSJ, 12/12/03, p.W15)(SSFC, 9/27/09, Par p.25)(AP, 1/8/12)(SFC, 1/6/18, p.A6) 1793 There was a yellow fever epidemic in Philadelphia. About 5,000 people were killed. Stephen Girard risked his life and fortune in stopping the epidemic. (WSJ, 1/2/97, p.6)(Econ, 5/14/16, p.52) 1794 Feb 14, 1st US textile machinery patent was granted, to James Davenport in Phila. 1794 May, Richard Allen purchased a blacksmith shop in Philadelphia and had it moved near St. Thomas. There he founded an African Methodist Episcopal (AME) church he called Bethel, "House of God." The Mother Bethel African Methodist Episcopal Church in Philadelphia was founded by Richard Allen after he was pulled from his knees one Sunday by a white usher while praying at St. George Methodist Episcopal Church. It later stood as the oldest parcel of land continuously owned by African Americans. The Richard Allen Museum contains 19th century artifacts from the church. In 1997 it was the world’s oldest AME church. The church elected its first female bishop in 2000. (SFC, 6/24/96, p.A19)(SFC, 7/12/00, 1794 Jul 17, In Philadelphia the African Episcopal Church of St. Thomas, one of the first black churches in the country, opened its doors. 1794 Aug 7, George Washington issued a proclamation telling a group of Western Pennsylvania farmers to stop their Whiskey Rebellion. In the US in western Pennsylvania, angry farmers protested a new federal tax on whiskey makers. The protest flared into the open warfare known as the Whiskey Rebellion between US marshals and whiskey farmers. ESM, p.16)(HNQ, 10/14/99) 1794 French Azilum near Towanda was planned as an asylum for Marie-Antoinette, her children and other loyalists of the monarchy seeking refuge from the French Revolution. Loyalists who kept their heads did come and settle. (HT, 5/97, p.18) 1797 Jul 10, 1st US frigate, the "United States," was launched in Philadelphia. 1798 Jan 30, A brawl broke out in the House of Representatives in Philadelphia. Matthew Lyon of Vermont spat in the face of Roger Griswold of Connecticut, who responded by attacking him with a hickory walking stick. Lyon was re-elected congressman while serving a jail sentence for violating the Sedition Acts of 1798. (AP, 1/30/98)(SFC, 4/27/00, p.A5)(WSJ, 10/29/04, 1798 The first big US bank robbery was at the Philadelphia Carpenter's Hall, which was leased to the Bank of Philadelphia. (SFEC, 2/20/00, Z1 p.2) 1799 Feb 15, The 1st US printed ballots were authorized in Pennsylvania. (440 Int’l., 2/15/99) 1799 In Pennsylvania the Lazaretto Quarantine Station was built in Tinicum Township to protect the Port of Philadelphia against the introduction of diseases that could lead to epidemics. The Lazaretto closed as a hospital in 1890 but then served as a resort and seaplane base before the start of World War I. In 2019 plans called for converting the structure into township offices. 1803 Feb 14, An apple parer was patented by Moses Coats in Downington, Penn. 1803 Sep 13, Commodore John Barry, considered by many the father of the American Navy, died in 1804 Feb 6, Joseph Priestley (b.1733), English-born US writer, philosopher and chemist, died in Pennsylvania. He became best known for having discovered oxygen. Priestley also figured out how to manufacture carbonated water and is sometimes called “the father of the soft-drink industry." In 2008 Steven Johnson authored “The Invention of Air: A Story of Science, Faith, Revolution, and the Birth of America." 10/05, p.1)(SFC, 1/9/09, p.E3) 1805 The Philadelphia harbor was dredged with a high-pressure steam engine invented by Oliver Evans. He was unable to get a proper patent for it. (WSJ, 6/4/08, p.A19) 1806 Shoemakers in Philadelphia formed a union. (WSJ, 1/11/99, p.R27) 1807 May 22, Townsend Speakman 1st sold fruit-flavored carbonated drinks in Phila. 1808 Feb 11, Anthracite coal was 1st burned as fuel, experimentally, in Wilkes-Barre, Pa. 1810 Feb 28, The 1st US fire insurance joint-stock company was organized in Philadelphia. 1810 Apr 17, Lewis Norton of Troy, PA., introduced his pineapple cheese. (440 Int'l, 4/17/03) 1811 Oct 29, The 1st Ohio River steamboat left Pittsburgh for New Orleans. 1811 A group of amateur naturalists formed the Academy of Natural Sciences in Philadelphia. (AH, 10/04, p.20) 1812 Dec 4, Peter Gaillard of Lancaster, Pa., patented a horse-drawn mower. 1812 The steamboat New Orleans was built in Pittsburgh and steamed to New Orleans but lacked sufficient power to return upstream. (ON, 7/02, p.9) 1813 Aug 23, Alexander Wilson (b.1766), Scottish-born poet and naturalist, died in Philadelphia. He had completed 7 volumes of “American Ornithology" and was working on an 8th volume when he died. 1814 Dec 1, The shallow-draft steamboat Enterprise, completed in Pittsburgh under the direction of keelboat captain Henry Miller Shreve, left for New Orleans to deliver guns and ammunition to Gen. Jackson. (ON, 7/02, p.9) 1814 Dec 14, The steamboat Enterprise, designed by keelboat captain Henry Miller Shreve, arrived in New Orleans with guns and ammunition for Gen. Jackson. It was immediately commandeered for military service. (ON, 7/02, p.9) 1815 Sep 8, Alexander Ramsey (d.1903), territorial governor of Minnesota (1849-1853), was born near Harrisburg, Pa. 1816 Dec 2, The first savings bank in the United States, the Philadelphia Savings Fund Society, opened for business. 1816 Pittsburgh was incorporated on the site of old Fort Pitt. (SFC, 1/29/00, p.E3) 1817 Mar 2, The 1st US Evangelical church building was dedicated in New Berlin, PA. 1818 Brown Brothers Harriman (BBH) was founded in Philadelphia as John A. Brown and Company, an importer of linen. On January 1, 1931, Brown Brothers And Company merged with Harriman Brothers & Company, an investment company started in 1912 with railway money. 1819 In Philadelphia Dr. Thomas W. Dyott, (druggist, patent-medicine vendor, and physician) purchased the Kensington Glass Works. He expanded the business and changed the name to the Dyottville Glass Works. He was forced out of the firm in 1838, but the glassworks continued operating until about (SFC, 1/14/98, Z1 p.2) 1821 Feb 23, College of Apothecaries, the 1st US pharmacy college, was organized in 1821 Nov 9, The 1st US pharmacy college held 1st classes in Philadelphia. 1824 The Second Bank of the United States, established by federal charter in 1791, was completed in Philadelphia by William Strickland. It was modeled after the Parthenon. From 1841-1934 it served as a Custom House. It was acquired by the National Park Service in 1939 and in 1974 became the home of the Peale portraits. The renovated museum reopened Dec 1, (WSJ, 2/22/05, p.D10) 1825 Philadelphia druggist Elie Magliore Durand first touted the effervescent soda water as a health drink. Shortly afterward, New York inventor John Matthews originated the fountain apparatus that conveniently rested on a pharmacist's counter to dispense carbonated drinks. 1829 Jul 4, Cornerstone laid for 1st US mint (Chestnut & Juniper St, Phila). 1829 Oct 23, The Eastern State Penitentiary in Philadelphia received its 1st prisoner, burglar Charles Williams (18). It was based on the Quaker idea of reform through solitude and reflection. In 1913 the Pennsylvania System of isolation was abandoned and the isolation practices ended. The prison was designed by John Haviland and was built on the outskirts of Philadelphia. The whole fortress-like exterior was just a façade hiding the radial structure of the inner prison. It opened to tourists in 1971 after being closed to prisoners. (WSJ, 9/19/97, p.B1)(AHHT, 10/02, p.18)(Insider, 1829 In Pennsylvania David G. Yuengling (d.1877), an immigrant from Germany, established the Eagle Brewery on Centre St. in Pottsville. As of 2016 the D.G. Yuengling & Son brewery was recognized as the oldest in the United States. 3/23/04, p.B5)(SFC, 6/23/16, p.C6) 1830 Sep 20, The National Negro Convention convened in Philadelphia with the purpose of abolishing 1830 George Brinton began constructing a home later called Rondelay in Chadds Ford. After extensive renovations the 6 bedroom home on 38.9 acres was listed for sale in 1998 for $2.9 mil. (WSJ, 4/3/98, p.W8) 1830-1850 The Pennsylvania German community made traditional hand-stitched show towels and most show towels date from this period. They were hung on a door in the main room of a house. (SFC,12/10/97, Z1 p.9) 1831 Feb 19, The 1st practical US coal-burning locomotive made its 1st trial run in Penn. 1832 Aug, In Pennsylvania 57 Irish immigrants died of cholera after traveling there to build a railroad. In 2009 their bones were found at a woodsy site known as Duffy's Cut, named after Philip Duffy, who hired the immigrants from Donegal, Tyrone and Derry to help build the Philadelphia and Columbia Railroad. In 2010 evidence indicated that at least some of the men’s remains showed signs of violence. (AP, 3/25/09)(AP, 8/16/10) 1832 Nov 29, Louisa May Alcott (d.1888), American author who wrote "Little Women," was born in Germantown, Pa. Under the pen name A.M. Barnard she wrote stories of violence and revenge that included "Pauline’s Passion and Punishment." "It takes people a long time to learn the difference between talent and genius, especially ambitious young men and (WUD, 1994, p.35)(SFC, 6/17/97, p.E3)(AP, 1832 The Girard Bank of Pennsylvania was founded. 1832 The Pittsburgh riverfront home of coal baron Abraham Hays flooded. Hays built a new mansion, which later became a stop on the Underground Railroad, harboring slaves who traveled a tunnel from the Monongahela River to the vast brick-lined basement. 1833 Aug 7, Powell Clayton, Brig. General (Union volunteers), (Gov-R-Ark), was born in Pa. 1833 Dec 4, American Anti-Slavery Society was formed by Arthur Tappan in Phila. 1833 John Mohler Studebaker was born in Gettysburg, Pennsylvania. In 1858 joined his two older brothers in a South Bend firm producing wagons. The company went on to become the world’s largest producer of farm wagons and carriages. (WSJ, 6/13/96, p.A12)(HNQ, 1/21/02) 1833 Richard Allen (73) published his autobiography: "The Life, Experience, and Gospel Labors of the Rt. Rev. Richard Allen." 1833 American Navy pensioners moved into what was then called the Naval Asylum, a 180-room stone building on the bank of the Schuylkill River in Philadelphia. The name was later changed to the Naval Home. It closed in 1977. 1834 William Russell Birch (b.1755), English-born artist, died. He had settled in Philadelphia with his son in 1794 and in 1800 published 28 drawn and engraved hand-colored images of Philadelphia. (SFC, 5/18/02, p.E6) 1835 Jul 6, John Marshall, the third chief justice of the Supreme Court, died at the age of 79. Two days later, while tolling in his honor in Philadelphia, the Liberty 1835 Jul 8, The US Liberty Bell in Philadelphia cracked while being tolled for Chief Justice John Marshall. It was never rung again. (HFA, ‘96, p.34)(HN, 7/6/98)(WSJ, 12/10/96, 1835 John Wise built and took off from Philadelphia in his first homemade balloon. In 1859 he attempted an express mail service by balloon from St. Louis to NYC. (ON, 11/00, p.6) 1836 The LaPorte house was built by John LaPorte, son of one of the founders of French Azilum (HT, 5/97, p.18) 1837 Feb 25, Cheyney University was established in Pennsylvania through the bequest of Richard Humphreys, and became the oldest institution of higher learning for African Americans. It was initially named the African Institute. However, the name was changed several weeks later to the Institute for Colored Youth (ICY). In subsequent years, the university was renamed Cheyney Training School for Teachers (July 1914), Cheyney State Teacher’s College (1951), Cheyney State College (1959), and eventually Cheyney Univ. of Pennsylvania (1983). 1838 Jul 11, John Wanamaker (d.1922), US merchant who founded a chain of stores in Philadelphia, (HN, 7/11/98)(ON, 12/05, p.6) 1839 Feb 24, A steam shovel was patented by William Otis, Philadelphia. 1839 Dec 4, The Whig Party opened a national convention in Harrisburg, Pa., where delegates nominated William Henry Harrison for president. Soon after the Whigs constructed a 10-foot ball of twine, wood and tin, covered with Whig slogans, and rolled it from Cleveland to Columbus, Ohio, and across the country. This was later deemed the first modern presidential and led to the expression "Keep the ball rolling." (AP, 12/4/99)(SSFC, 1/11/04, p.D6)(Econ, 12/5/15, 1840 Apr 2, The Association of American Geologists held its first meeting in Philadelphia. 1840 A US no-bail-out policy forced some state into default. Several US states had loaded up on unsustainable debt following an extended period of easy credit. These states consequently found payments on their existing bonds increasingly unaffordable. Between 1841 and 1843 Arkansas, Illinois, Indiana, Louisiana, Maryland, Michigan, Mississippi, Pennsylvania and one territory – a proto-state called Florida – defaulted. (Econ, 2/11/12, p.57)(http://tinyurl.com/6pgf4wq) 1840s The Chain Gang, the earliest Mummers club, was formed in Philadelphia. (SFC, 12/31/00, p.A10) 1841 Dentist Joseph Wilson authored “Sketches of the Higher Classes of Coloured Society in (Econ, 8/6/16, p.67) 1841 In Philadelphia Volney B. Palmer began the first advertising agency. He sold newspaper space to out-of-town advertisers. (SFC, 7/5/97, p.E3) 1841 The Bartleson-Bidwell Party made the trek to California. John Bidwell was on the 1st wagon train over the Sierra Nevada and later founded Chico. Also in the group was Paul Geddes, who had robbed a bank in Philadelphia, and renamed himself Talbot Green. His true ID was exposed in 1850 as he was about to run for mayor of SF. (SFC, 12/7/02, p.E4)(SSFC, 9/24/06, p.B3)(SFC, 6/14/14, p.C2)(SFC, 2/6/21, p.B2) 1844 May 22, Mary Cassatt, impressionist painter, was born in Alleghany City (later Pittsburgh). [see May 22, 1845] (HFA, ‘96, p.30)(AHD, p.209)(HN, 5/22/98)(WSJ, 1845 Apr 10, Over 1,000 buildings were damaged by fire in Pittsburgh, Pa. 1845 May 22, Mary Cassatt (d.1926), American impressionist painter and printmaker, was born in Alleghany, Pa. Much of Cassatt’s early life was spent in Europe with her wealthy family. She attended the Pennsylvania Academy of the Fine Arts from 1861 to 1865 and worked briefly with Charles Joshua Chaplin in Paris, but preferred working her own way and copying old masters. She was a close friend of and greatly influenced by Edgar Degas. He admired her entry in the Salon of 1874, and at his invitation she joined the Impressionists and afterward showed her works at their exhibits. Degas’ influence is apparent in Cassatt’s mastery of drawing and in her unposed, asymmetrical compositions. Initially, Cassatt was a figure painter whose subjects were groups of women drinking tea or on outings with friends. After the great exhibition of Japanese prints held in Paris in 1890, she brought out her series of 10 colored prints, such as "Woman Bathing," and "The Coiffure," in which the influence of the Japanese masters Utamaro and Toyokuni is apparent. Cassatt urged her wealthy American friends and relatives to buy Impressionist paintings, and in this way, more than through her own works, she exerted a lasting influence on American taste. She was largely responsible for selecting the works that make up the H.O. Havemeyer Collection in the Metropolitan Museum of Art, New York. (HFA, ‘96, p.30)(AHD, p.209)(FAMSF, Mar, 98) 1846 Feb 23, The Liberty Bell in Philadelphia tolled for the last time, to mark George Washington’s birthday. A hairline fracture had developed since 1817 and a failed attempt to repair it resulted in the crack. In 2010 Tristram Riley-Smith authored “"The Cracked Bell: American and the Afflictions of Liberty." (HN, 2/23/98)(SFEC, 8/16/98, p.T5)(Econ, 1/30/10, 1847 May 7, The American Medical Association was founded in Philadelphia. (AP, 5/7/97) (HN, 5/7/98) 1847 Sep 11, Stephen Foster’s "Oh! Susanna" was first performed in a saloon in Pittsburgh. 1848 Oct 16, The 1st US homeopathic medical college opened in Pennsylvania. 1849 Dec 19, Henry Clay Frick (d.1919), coal and steel magnate, was born in West Overton, Penn. 1850 Mar 11, The Pennsylvania legislature passed an act to incorporate the Female Medical College of Pennsylvania, the first regular medical school for women in 1850 Oct 12, The 1st women's medical school, the Female Medical College of Pennsylvania, opened 1850 Oct, Paul Geddes, who had robbed a bank in Philadelphia and renamed himself Talbot H. Green in California, was exposed as he was about to run for mayor of SF. 1850-1859 The Lehigh Valley town of Bethlehem, Pennsylvania, became an iron-making center in the 1850s thanks to discoveries of coal and iron ore nearby. (WSJ, 10/8/08, p.A15) 1851 Sep 11, Edward Gorsuch, a wealthy slave owner from Maryland, confronted William Parker and accused him of harboring 4 runaway slaves near the abolitionist town, Christiana, Pennsylvania. This was one year after the second fugitive slave law (first law was on February 12, 1793) was passed by Congress, requiring the return of all escaped slaves to their owners in the South. Gorsuch was killed during the skirmish and Parker was forced to flee to Canada. (AH, 10/02, p.49) 1851 Dec 11, In Philadelphia 37 men, on trial in federal court for defying the Fugitive Slave Law, were deemed not guilty by a jury with 15 minutes of deliberation. (AH, 10/02, p.54) 1851 In Pennsylvania Bernard Lauth, founded the American Iron Company. The firm of Jones and Lauth was founded in 1852 by B. F. Jones a few miles (~4 km) south of Pittsburgh along the Monongahela River. Lauth's interest was bought in 1854 by James H. Laughlin. 1852 Feb 16, Charles Taze Russell (d.1916) was born in Pittsburgh. In 1872 Russell abandoned the Adventist movement and formed the International Bible Students Association, which was later named Jehovah’s Witnesses (1931). 1852 John Neumann, Catholic missionary, became the bishop of Philadelphia. he was later made a (SFEC, 9/14/97, p.A18) 1853 Keebler Foods was founded in Philadelphia. It was acquired by Kellogg in 2001. 1855 Jul 18, In Philadelphia William Still, a leader in the Underground Railroad, liberated Jane Johnson and her 2 sons from Col. John H. Wheeler, the recently appointed US Minister to Nicaragua. Still was tried and acquitted. "The Underground Railroad" by William Still was published in (ON, 10/01, p.5) 1855 Organic chemist Benjamin Stillman laid the foundations for the Pennsylvania oil rush by his discovery that petroleum could be distilled into lubricants and kerosene for cooking and illumination. Suddenly there was a use for the crude oil that seeped to the surface, annoying farmers by ruining the land and polluting the water supply. 1856 Jun 17, In Philadelphia, the Republican Party opened its first national convention. John C. Fremont (1830-1890), American explorer, was the 1st Republican presidential candidate. His platform pledged to end polygamy and slavery. He lost to James Buchanan by about 500,000 votes. Fremont went on to serve as territorial governor of Arizona from 1878 to 1883. In 2003 Lewis L. Gould authored "Grand Old Party: A History of (AP, 6/17/97)(HN, 6/17/98)(SFEC, 2/13/00, BR p.5)(HNQ, 3/11/00)(WSJ, 9/7/01, p.W17)(SSFC, 11/23/03, p.M1) 1856-1930 Henry Chapman Mercer, archeologist and collector. He designed and constructed the Mercer Museum in (AH, 4/01, p.18) 1857 Jan 6, Patent for reducing zinc ore was granted to Samuel Wetherill in Penn. 1857 Sep 13, Milton S. Hershey, chocolate manufacturer and philanthropist, was born in Dauphin 1857 Nov 5, Ida M. Tarbell (d.1944), muckraking journalist, was born in Erie County, Pa. 1858 Mar 23, Eleazer A. Gardner of Philadelphia patented the cable street car, which ran on overhead 1858 Mar 30, Hyman L. Lipman of Philadelphia patented the pencil. 1858 The Market Square Presbyterian Church was built in Harrisburg. (SSFC, 4/13/03, p.D6) 1859 Mar 21, Zoological Society of Philadelphia, the 1st in US, was incorporated. 1859 Aug 27-28, The US oil business was born in Titusville, Pa. Former army officer Colonel Edwin L. Drake drilled the first oil well in Titusville, Pa., striking oil at 70 feet and setting off a wild scramble for wealth similar to the California gold rush of 1849. The land belonged to the Pennsylvania Rock Oil Company. Until that time, the company had simply collected oil that seeped out of the ground. Drake's plan was to produce it in large quantities for use in heating and illumination. Overnight oil fields sprang up in Pennsylvania but competition, disorganization and oversupply kept oil prices low. It was not until John D. Rockefeller and the Standard Oil Company came onto the scene in 1870 that the petroleum industry developed into a vastly profitable, although much hated, monopoly. (HFA, '96, p.36)(AP, 8/27/97)(HNPD, 10/4/98)(WSJ, 10/4/96, p.A9)(HNQ, 2//99) 1860 Jul 14, Owen Wister (d.1938), novelist, was born in Germantown, Pa. His 1902 novel "The Virginian" inspired 5 films. (HN, 7/14/01)(SFC, 1/9/02, p.D8)(AH, 10/02, p.18) 1860 William McGillin began opened McGillin’s Olde Ale House in Philadelphia. In 2009 it celebrated its sesquicentennial. (SFC, 8/5/09, p.A4) 1860 John and Frank Wyeth established a drugstore in Philadelphia. It grew to become Wyeth-Ayerst Laboratories in 1926 and was later acquired by American (SFC, 1/21/98, p.B2) 1860 John Neumann, the 4th Bishop of Philadelphia, died. He was later made the patron saint of (SFC, 12/31/00, p.A10) 1861 Feb 5, The kinematoscope was patented by Coleman Sellers in Philadelphia. 1861 William Wrigley, Jr., was born in Philadelphia. He began his business career by selling soap manufactured by his father. In 1891, Wrigley moved to Chicago where he founded and became president of Wm. Wrigley, Jr. Company, manufacturers of chewing gum, earning him the money to acquire the Chicago Cubs and to build Wrigley‘s Stadium. Wrigley is especially noted for his effective advertising techniques. 1861 James Buchanan, 15th President of the United States, retired to Wheatland, his Pennsylvania home, on the eve of the American Civil War. Attracted to the privacy, quiet and beauty of its rural location, Buchanan bought the 22-acre property in 1848 while he was finishing out his term as secretary of state under President James Polk. The Federal-style house was built in 1828 for William Jenkins, a wealthy lawyer and banker who named his estate "The Wheatlands" because of its setting among wheat fields. 1861 The Bassett family became making ice cream in Philadelphia. The ice cream was later called Bassetts and considered by some to be the best in the world. (WSJ, 8/1/00, p.A24) 1861 In Philadelphia John Wanamaker (1838-1922) and Nathan Brown (d.1868) purchased a 6-story men’s clothing store called McNeill’s Folly and renamed it the Oak Hall Clothing Bazaar. (ON, 12/05, p.4) 1861 John Wallace Cowden founded the Cowden pottery in Harrisburg, Pa. It became Cowden & Son from 1888-1904. (SFC, 3/29/06, p.G6) 1862 Feb 26, Cornelius Felton (b.1807), president of Harvard Univ., died in Chester, Pen., after 2 years in office. 1862 May 18, William High Keim (b.1813), US Union Brigadier-General, died in camp of fever in Harrisburg, Pa. 1862 A dam across the South Fork Creek, a tributary of the Little Conemaugh River, collapsed and damaged some property in Johnstown. (ON, 12/99, p.9) 1863 Jun 26, Jubal Early and his Confederate forces moved into Gettysburg, Pennsylvania. 1863 Jun 28, General Meade replaced General Hooker three days before the Battle of Gettysburg. 1863 Jun 28, Officers of the Confederate Army of Northern Virginia’s Second Corps were looking at Harrisburg through field glasses from across the Susquehanna River just a day or two before a developing battle at Gettysburg called them away. Harrisburg, Pennsylvania, the Keystone State’s capital was a major hub for rail traffic from every direction. Consequently, it was also the point through which the hard, slow-burning coal used by ships, locomotives, and furnaces traveled on its way from the mines of north central Pennsylvania to military and industrial customers. Philadelphia, an important ocean port east of Harrisburg and connected to it by rail, would have been virtually defenseless against an attack from its landward side. If Lee had taken Harrisburg, he would also have been perfectly positioned to threaten Washington, D.C., from the north. 1863 Jun 29, Lee ordered his forces to concentrate near Gettysburg, PN. 1863 Jun 30, Union and Confederate cavalries clashed at Hanover, Pennsylvania. 1863 Jun, A Civil War-era shipment of Union gold was either lost or stolen on its way to the US Mint in Philadelphia. In 2018 an FBI excavation searched for the lost gold after a father-and-son duo, Dennis and Kem Parada, provided a tip-off to the federal agency. The FBI claimed nothing was found at an area called Dent’s Run, northeast of Pittsburgh. 1863 Jul 1, The opening shot at the Battle of Gettysburg was at 7:30 a.m. In the first day's fighting at Gettysburg, Federal forces retreated through the town and dug in at Cemetery Ridge and Cemetery Hill. Gen. Robert E. Lee's ordered Lt. Gen. Richard Ewell, "Take the hill if practicable, but do not bring on a general engagement..." Books on the campaign included "The Gettysburg Campaign, A Study in Command," by Edwin B. Coddington and "Gettysburg: Culp's Hill and Cemetery Hill," by Harry W. Pfanz. The novel "While Gods and Generals" by Jeff Shaara, son of Michael Shaara, describes the years leading up to the battle. (HFA, '96, p.32)(AP, 7/1/97)(SFEC, 6/21/98, 1863 Jul 1, John Fulton Reynolds (42), Union general, died in battle at Gettysburg. 1863 Jul 1-3, From the opening shot at 7:30 a.m. on July 1, 1863, to 4 p.m. on July 3, when the last rebel assault was repulsed, the Union and Confederate armies suffered an estimated 50,000 casualties in the Battle of Gettysburg. It was the bloodiest battle the country had yet seen. Upon whom the responsibility for the South's failure at Gettysburg rests has been widely debated, but five months after the epic battle, Confederate General Robert E. Lee admitted, "I thought my men were invincible." The fighting in the small Pennsylvania town marked a pivotal point in the Union's ascent to victory and helped decide the outcome of the Civil War. 1863 Jul 2, The Union left flank held at Little Round Top during 2nd day of the Battle of Gettysburg. Union Gen. Daniel Sickles was severely wounded and had his leg amputated. In 2002 Thomas Keneally authored "American Scoundrel: The Life of the Notorious Civil War General Dan Sickles." (WSJ, 3/29/02, p.W10)(SFC, 4/17/02, p.D1)(AH, 1863 Jul 3, The Civil War's Battle of Gettysburg in Pennsylvania ended after three days in a major victory for the North as Confederate troops retreated. The last Confederate assault at Gettysburg was Pickett’s Charge against the center of the Union line that left some 7,000 of 13,000 [15,000] Confederate troops dead. Lt. Gen. James Longstreet gave Maj. Gen. George Pickett the assent. General Lee took responsibility. In 1974 Michael Shaara published "The Killer Angels," a novel about the (SFC, 7/7/96, T6)(SFC,2/17/97, p.A3)(AP, 7/3/97)(SFEC, 6/21/98, p.D5)(HN, 7/3/98)(WSJ, 9/11/98, p.W10) 1863 Jul 4, General Lee’s army limped toward Virginia after defeat at Gettysburg. 28,063 of 75,000 confederate soldiers were lost. General Meade’s army suffered 23,049 soldiers killed, wounded and missing. (SFC, 7/7/96, T6) 1863 Jul 4, Paul Joseph Revere, US grandson of Paul Revere, Union brig-gen, died from wounds at 1863 Jul 6, Vincent Strong (b.1837), US Union brig-general, died from wounds at Gettysburg. (MC, 6/17/02)(MC, 7/6/02) 1863 Nov 19, President Lincoln delivered the Gettysburg Address as he dedicated a national cemetery at the site of the Civil War battlefield in Pennsylvania. Lincoln had been asked to deliver a few "appropriate remarks" to the crowd at the dedication of the National Cemetery at the site of the Battle of Gettysburg, Pennsylvania. His address was almost ignored in the wake of the lengthy oration by main speaker Edwin Everett, the former governor of Massachusetts. In fact, Lincoln's speech was over before many in the crowd were even aware that he was speaking. Lincoln concluded his speech with this vow: "We here highly resolve that these dead shall not have died in vain; that this nation, under God, shall have a new birth of freedom; and that government of the people, by the people, for the people, shall not perish from the 11/19/97)(ON, 8/07, p.1) 1863 Nov, In Pennsylvania the Harrisburg Patriot and Union newspaper described Pres. Lincoln’s speech at Gettysburg as “silly remarks" that deserved a “veil of oblivion." In 2013 the Patriot-News of Harrisburg retracted the editorial penned by its predecessor. (SFC, 11/15/13, p.A7) 1863 The Mütter Museum was founded as part of the College of Physicians of Philadelphia was an educational service for practicing physicians. (NW, 11/18/02, p.14) 1863 A locomotive named the Gov. Stanford was built by Richard Norris & Son in Philadelphia and shipped around Cape Horn to California by schooner. It hauled the Central Pacific’s 1st freight and passenger trains and later was made a centerpiece at the California State Railroad Museum in (SSFC, 8/8/04, p.D5)(SSFC, 2/9/14, p.P2) 1864 Jul 30, Gen. Jubal Early ordered Confederate troops to attack Chambersburg, Pennsylvania. The town was burned by Confederate forces under Gen. McCausland 1865 Daniel C. Ripley founded a lamp manufacturing firm in Pittsburgh, Pa. the following year he joined with 5 partners to form Ripley & Co. Ripley was granted a patent in 1868 for a glass oil lamp. The company merged with others in 1891 to form the U.S. Glass Co. of Pittsburgh. (SFC, 12/14/05, p.G4)(SFC, 4/4/07, p.G2) 1865-1877 In eastern Pennsylvania the Molly McGuires, a secret society of Irish miners, waged a war with arson, murders and beatings, on coal-mine owners. (WSJ, 10/7/97, p.A20) 1868 Aug 11, Thaddeus Stevens (1792-1868), Pennsylvania Republican and architect of Radical 1869 Jun 9, Charles Elmer Hires sold his 1st root beer in Phila. 1869 Sep 6, 110 miners, a number of them young boys, were killed in coal mine disaster which occurred early in the morning in Avondale, Pennsylvania, when a fire broke out in a mineshaft, cutting off the miners' escape route and their only source of air. 1869 The first Lithuanian community was established in Danville, Pennsylvania. 1869 Henry J. Heinz partnered with L.C. Noble to form Heinz & Noble in Sharpsburg, Pa., selling fruit and vegetable preserves. They produced tomato and walnut ketchup for 24 cents per gallon and sold them from whiskey 1870 Feb 5, The 1st motion picture was shown to a theater audience in Philadelphia. 1870 Mar 21, The grave of Ellen Shannon in Girard, Pennsylvania reads: Ellen Shannon, Who was fatally burned March 21, 1870 by the explosion of a lamp filled with "R.E. Danforth’s Non-Explosive Burning Fluid." (e-mail, Riddiough, 5/16/99) 1870 Harry "the Sundance Kid" Longabaugh was born in Lancaster County. 1870-1882 Alexander Conrad was a stoneware manufacturer in southwestern Pennsylvania during this time. (SFC, 4/15/98, Z1 p.6) 1871 The construction of City Hall in Philadelphia began. (SFEC, 8/16/98, p.T1) 1871 The Red Star Line, an ocean passenger line, was founded as a joint venture between the International Navigation Company of Philadelphia, which also ran the American Line, and the Société Anonyme de Navigation Belgo-Américaine of Antwerp, Belgium. (http://en.wikipedia.org/wiki/Red_Star_Line)(SSFC, 4/21/13, p.H4) 1871 The Knights of Labor organization was started as a secret order at a meeting of tailors called by Uriah Stephens in Philadelphia. The Knights of Labor was organized on a national basis in 1878. It was an industrial union open to all gainfully employed skilled or unskilled workers and headed by a General Assembly. By 1886 there were 5,892 local assemblies and more than 700,000 members. Among other reforms, the Knights supported an 8-hour day, graduated income tax, boycotts, arbitration, and consumer and producer cooperatives. The organization began to decline after 1886. [other sources give 1869 as the founding year.] 1872 Aug 1, The first long-distance gas pipeline in the U.S. was completed. Designed for natural gas, the two-inch pipe ran five miles from Newton Wells to 1872 The International Bible Students Association was founded in Pittsburgh by Charles Taze Russell. During the 1870s, Charles Taze Russell established himself as an independent and controversial Adventist teacher. Russell was succeeded as president in 1917 by Joseph Franklin Rutherford (Judge Rutherford; 1869–1942), who changed the group’s name to Jehovah’s Witnesses in 1931 to emphasize its members’ belief that Jehovah, or Yahweh, is the true God and that the Witnesses were his specially 1874 Feb 3, Gertrude Stein (d.1946), poet and novelist, was born in Pittsburgh, Pa. Her older brother, Michael, managed the family business, which included San Francisco's Market Street railway line. Her parents were Daniel and Milly. The family returned to America from Europe in 1878, and settled in Oakland, California, where Gertrude attended First Hebrew Congregation of Oakland's Sabbath school. Her relationship with her brother, Leo (1872-1947), abruptly ended in 1914. Her work included "Three Lives," "G.M.P." and "Tender Buttons." Stein coined the term "Lost Generation" in reference to the disillusioned intellectuals and aesthetes of the post-World War I years. The 40-year relationship between Gertrude and Leo is told by Brenda Wineapple in "Sister Brother, Gertrude and Leo Stein." "Everybody gets so much information all day long that they lose their common sense." "It is awfully important to know what is and what is not your business." (SFEC, 8/11/96, DB, 1874 Jun 25, Rose Cecil O’Neill (d.1944), illustrator, writer and creator of the Kewpie doll, was born in Wilkes-Barre, Pa. 1874 Jul 1, The 1st US zoo opened in Philadelphia. 1875 Nov 16, William Bonwill (1833-1899), a Philadelphia dentist, provided specifications for a patent for an electrical tooth-filling Instrument, a dental mallet to impact gold into cavities. The patent application was filed in 1873 and accepted in 1888. 1875 John Wanamaker purchased an abandoned railroad depot in Philadelphia and converted it into a large store, called John Wanamaker & Co. "The Grand Depot". Wanamaker's is considered the first department store in the 1876 Mar 12, In Philadelphia the first department store, The Grand Depot, opened. John Wanamaker turned an abandoned railway depot into one of the world’s 1st 1876 May 10, Centennial Fair opened in Philadelphia. Centennial Hall was built in Philadelphia, Pa., to commemorate the country’s 100th birthday. The US Centennial Exhibition was a world’s fair celebrating the founding of the US and drew over 9.9 million people. The US population at this time was 46 (Hem, 6/96, p.108)(SFC,12/10/97, Z1 p.9)(MC, 1876 Jun 5, Bananas became popular in US following the Centennial Exposition in Phila. 1876 Jun 26, Alexander Graham Bell demonstrated his telephone at the Centennial Exposition in (SFC, 2/3/97, p.D1) 1876 Dec 6, The 1st US crematorium began operation in Washington, Penn. 1876 Edward Mitchell Bannister, African-American artist, won a 1st place prize at the Centennial Exposition, but was turned away from the exhibition hall when he went to collect his medal. (WSJ, 8/8/00, p.A20) 1876 In the US the Workingmen’s Party of the United States (WPUS) was founded in Philadelphia, Pa. In 1878 it reformed as the Socialist Labor Party. 1876 The high-wheel bicycle was introduced in the US at the Centennial Exhibition in Philadelphia. (ON, 2/10, p.3) 1878 Mar 20, Thomas Fisher, an alleged member of the Molly McGuires, was hung at the Carbon County Prison of Mauch Chunk, Pa. He had been convicted of the murder of Morgan Powell, a supervisor for the Lehigh Coal and Navigation Company. Fisher insisted up to his death on his innocence. (HT, 4/97, p.20) 1878 Jul 3, John Wise flew the first dirigible in Lancaster, Pennsylvania. 1878 Dec 26, The 1st US store to install electric lights was in Philadelphia. 1878 The Thomas Eakins (1844-1916) painting "The Gross Clinic" was bought for $200 by Thomas Jefferson University, a medical and health sciences school in Philadelphia. In 2006 The National Gallery of Art agreed to buy the painting for a record $68 million, however the deal was matched by local institutions and the painting remained in Philadelphia. (AP, 11/11/06)(WSJ, 12/26/06, p.D8) 1879 Apr 9, W.C. Fields (Claude William Dukinfield [Dukenfield]), comedian, was born in Philadelphia. He began his career as a vaudeville juggler, appeared on Broadway and in motion pictures. [see Jan 29, 1880] (HN, 4/9/98)(HNQ, 9/30/01) 1879 Jun 21, F.W. Woolworth opened his 1st store. It failed almost immediately. Frank Woolworth added 10-cent items to the Great 5-Cent Store in Lancaster, Pa., and created Woolworth’s five-and-ten. This was his 2nd attempt after a failure in Utica. He took in $127 during his first day of business. (WSJ, 9/26/96, p.B1)(SFC,10/20/97, p.B2)(MC, 1879 In downtown Philadelphia the Provident Life and Trust Building was completed. It was designed by Frank Furness (1839-1912). (WS, 6/26/01, p.A21) 1879 Lt. Col. Richard Henry Pratt persuaded Washington to hand over the mothballed Carlisle military barracks in Pennsylvania for use as a school for American Indians. In the early 20th century the school became a football powerhouse, beating Army in 1912. In 1918 the school was turned into a hospital to receive soldiers wounded in WW I. (WSJ, 1/7/07, p.P9) 1880 Jan 6, Tom Mix, silent screen cowboy actor (Dick Turpin), was born in Mix Run, Pa. 1880 Jan 29, W.C. Fields, comedian and actor, was born as Claude William Dukinfield [Dukenfield]. His films included David Copperfield and My Little Chickadee. [see Apr 9 1879] 1880 Jun 18, John Sutter (b.1803), Swiss-born California settler (gold discovered on his land), died in Lititz, Pa. (SSFC, 4/13/03, p.D6)(MC, 6/18/02) c1880-1920 In Philadelphia the Juvenile Aid Society was begun by the 15,000 Jews of German extraction to deal with the wave of some 200,000 East European Jews who arrived during (WSJ, 6/18/99, p.A20) c1881 The Norristown State Hospital was established. It served the chronically mentally ill and the worst of the criminally insane. (SFC, 6/19/99, p.A4) 1881 The South Fork Hunting and Fishing Club purchased the old damn site across a tributary of the Little Conemaugh River and rebuilt the old damn without the original sluice pipes. They blocked the spillway to prevent fish from (ON, 12/99, p.9) 1881 The Wharton School was founded in Pennsylvania. In 2003 it was recognized as the oldest and best business school in the US. (WSJ, 9/17/03, p.A1) 1883 Feb 23, American Anti-Vivisection Society was organized in Philadelphia. 1883 Haverford College was founded in Haverford, Pa., by Quakers. (WSJ, 7/24/03, p.A1) 1884 French artist Paul Philippoteaux (1846-1923) and team of 20 created in Paris the massive Cyclorama painting titled “The Battle of Gettysburg." It was originally 377 feet in circumference. They then shipped it to the US, where it was first displayed in Boston. The US National Park Service acquired it in 1942. In 2008 a 5-year, $15 million restoration project was completed and it was reopened to the public at the Gettysburg National Military Park in Gettysburg, Pa. 1885 Mar, In Loganville, Pa., Dr. George E. Holtzapple (22) saved Fred Gable (16), who was suffering from pneumonia, by supplying the boy with pure oxygen. Oxygen therapy became the only effective treatment for pneumonia until antibiotics became available in the 1940s. (ON, 4/07, p.10) 1885 The Cincinnati Stock Exchange was founded. It closed its trading floor in 1980 and became America's first fully computerized exchange. Bernard Madoff, a former chairman of the NASDAQ Stock Market and founder of Bernard L. Madoff Investment Securities, was one of the few NASDAQ market-makers who competed with the New York Stock Exchange, by trading stocks listed on the Big Board. His broker/dealer firm did this through an electronic market that was operated at the Cincinnati Stock Exchange. 1885 Isaac Mayer Wise united pockets of Jewish immigrants and assembled 15 rabbis in Pittsburgh to articulate a platform for the Union of American Hebrew Congregations, the Hebrew Union College, and the Central Conference of American Rabbis. The organization of Reform Judaism discussed the Mitzvot, the 613 commandments in the Torah, and accepted only the moral laws as binding. (WSJ, 6/4/99, p.W15) 1885 Elizabeth Cochran (21) began to produce article for the Pittsburgh Dikspatch under the name “Nelie Bly." In 1887 she moved to NYC hoping to find work at the New (ON, 6/20/11, p.11) 1886 Feb 13, Painter Thomas Eakins resigned from the Philadelphia Academy of Art over controversial use of male nudes in a coed art class. 1887 Feb 2, People began gathering at Gobbler's Knob in Punxsutawney, Pa., to witness the groundhog's search for its shadow. (WSJ, 2/2/99, p.B1) 1887 Ford City, Pa., was founded by John B. Ford, head of the Pittsburgh Plate Glass Co. on the shore of the Allegheny River. Later some 47 acres of the factory grounds were fenced off due to contamination from arsenic left behind by decades of industrial glassmaking. (WSJ, 8/12/97, p.B1) 1887 The Pennsylvania Railroad train station at Harrisburg opened. (SSFC, 4/13/03, p.D6) 1887 Pennsylvania House was founded in Lewisburg, Pa., to make high-quality case furniture. In 2000 La-Z-Boy bought the company and in 2004 moved production to (SFC, 6/4/08, p.G3) 1887 The Lanston Monotype Machine Company was founded by Tolbert Lanston in Philadelphia, Pennsylvania. Lanston had a patented mechanical method of punching out metal types from cold strips of metal which were set (hence typesetting) into a matrix for the printing press. (http://en.wikipedia.org/wiki/Monotype_Imaging)(Econ, 6/28/14, p.52) 1888 Mar 6, William Bonwill of Philadelphia patented revolving-hammer mechanical dental pluggers, by which the plugging-tool is hit a rapid series I 5 of blows to impact the gold in the teeth. 1888 Aug 7, The revolving door, the brainchild of Philadelphia inventor Theophilus Van Kannel (1841-1919), was patented. In 1889 he founded the Van Kannel Revolving Door Company. 1889 Jan 9, A tornado struck Brooklyn, NY, when Flatbush was farmland. A twister blew through what are now the neighborhoods of Carroll Gardens, Boerum Hill, Downtown, Fort Greene and Williamsburg, blowing roofs off houses and uprooting trees, but killing no one. 14 people were killed by the tornado in Pittsburg, Pa. 1889 May 31, Johnstown, Pennsylvania was destroyed by a massive flood. The South Fork Dam across a tributary of the Little Conemaugh River collapsed under pressure from the rain-swollen Lake Conemaugh. Water slammed into Johnstown, Pa., 55 miles southeast of Pittsburgh and killed 2,209 people in a flood and related fire. Torrential rains had weakened the poorly constructed dam, located 14 miles upstream from the city. By the afternoon of May 31, after desperate efforts to shore up the earthen dam had failed, it broke and unleashed a 40-foot-high wave of water and debris into Johnstown with the force of Niagara Falls. Buildings and trees, along with animals and people--both dead and alive--piled up against the Pennsylvania Railroad Company's Stone Bridge. The mountain of debris then caught fire, trapping hundreds. More than 2,000 people lost their lives in the devastating Johnstown Flood. The South Fork Dam had been constructed to create Lake Conemaugh, a playground for the wealthy members of the South Fork Fishing and Hunting Club. In 1959 Richard O'Connor published "Johnstown, the Day the Dam Broke." In 1968 David McCullough authored “The Johnstown Flood." (SFC, 3/24/97, p.C2)(AP, 5/31/97)(HN, 5/31/98)(WSJ, 1/27/06, p.P8) 1889 Nov 16, George S. Kaufman, American playwright and screenwriter, was born in Pittsburgh, Pa. His plays included "Dinner at Eight," "You Can't Take it With You" and "The Man Who Came to Dinner." (HN, 11/16/99)(MC, 11/16/01) 1889 Clara Barton and her Red Cross group spent 5 months helping victims of the Johnstown flood. (SFC, 9/17/01, p.A6) 1890 Aug 27, Man Ray (d.1976) was born as Emmanuel Radinski in Philadelphia, Pa. A painter and photographer, he and Marcel Duchamp founded the Dadaism movement. 1890 The Westmoreland Glass Co. began making glass containers in Grapeville, Pa. Operations continued to 1984. (SFC, 7/11/07, p.G4) 1891 Pennsylvania’s first free library was chartered. (Econ, 2/14/09, p.40) 1892 Mar 3, 1st cattle tuberculosis test in US was made at Villa Nova, PA. 1892 In Pennsylvania the Reading Railroad station opened in Philadelphia. It later became the home of the Reading /Terminal Market. (SSFC, 5/25/14, p.P4) 1892 Pennsylvania’s Mansfield Univ. played college football’s first night game. (WSJ, 9/26/08, p.A1) 1892 Henry Clay Frick, partner of Andrew Carnegie, engineered a bloody clash with the labor union at the Pittsburgh Homestead Mill. 9-10 workers and 3 Pinkerton guards were killed and the Amalgamated Association of Iron and Steel Workers union was crushed. (SFEC,1/20/97, p.D1)(WSJ, 5/12/03, p.A6) 1893 Feb 28, Edward Acheson of Pennsylvania, patented an abrasive he named "carborundum." 1893 Jun 14, Philadelphia observed the first Flag Day. 1894 Apr 5, 11 strikers were killed in riot at Connellsville, Penn. 1894 May 11, Martha Graham, choreographer (Appalachian Spring), was born in Allegheny, Penn. 1894 Milton Hershey (1857-1945) founded Hershey Foods in Pennsylvania. He built an industrial town near where he was born and named it after himself. (WSJ, 7/26/02, p.B1)(SSFC, 4/13/03, p.D1)(Econ, 1895 Sep 3, The first professional American football game was played in Latrobe, Pennsylvania between the Latrobe Young Men’s Christian Association and the Jeannette Athletic Club. Latrobe wins 12-0. 1896 Feb 28, Philip Showalter Hench, physician (cortisone-Nobel), was born in Pittsburgh. 1896 May 7, Dr. Henry Howard Holmes (b.1860), serial killer, was hanged to death in Philadelphia, Pennsylvania. Born as Herman Webster Mudgett in Gilmantown, New Hampshire, to a devout Methodist family, Holmes spent much of his childhood torturing animals. He later graduated from the University of Michigan with a medical degree. Holmes financed his education with a series of insurance scams whereby he requested coverage for nonexistent people and then presented corpses as the insured. In 1886, Holmes moved to Chicago to work as a pharmacist. A few months later, he killed the elderly owner of the store but told everyone that the man had left him in charge. With a new series of cons, Holmes raised enough money to build a giant, elaborate home across from the store. The home, which Holmes called "The Castle," had secret passageways, fake walls, and trapdoors. Young women in the area, along with tourists who had come to see the 1893 World's Fair in Chicago, and had rented out rooms in Holmes' castle, suddenly began disappearing. Medical schools purchased many human skeletons from Dr. Holmes during this period but never asked how he obtained the anatomy specimens. Holmes was finally caught after attempting to use another corpse, his assistant Benjamin Pitezel, in an insurance scam. He confessed, saying, "I was born with the devil in me. I could not help the fact that I was a murderer, no more than a poet can help the inspiration to sing." Reportedly, authorities discovered the remains of over 200 victims on his property. 1896 In Pennsylvania American Rabbi Joseph Krauskopf bought 118 acres of land about 25 miles north of Philadelphia. The National Farm School (later Delaware Valley College), open to all faiths, began the following year with 10 students. Krauskopf had met Leo Tolstoy on an 1894 trip to Russia, during which the author of "War and Peace" said US immigrants would be better off tilling soil than living in cramped industrial cities. In 2010 the Warwick Foundation of Bucks County gave the school an estimated $30 million in property and cash. 1897 Feb 2, Fire destroyed the Pennsylvania state capitol in Harrisburg. A new statehouse was dedicated on the same site nine years later. 1897 May 14, "Stars and Stripes Forever" by John Phillip Sousa was performed for the first time in 1897 Sep 10, Police shot at striking mine workers in Pennsylvania and 20 people were killed. 1897 Sep 11, A strike by some 75,000 coal miners in Pennsylvania, Ohio and West Virginia ended after 10 weeks. Concessions included an eight-hour work day, semi-monthly pay, and the abolition of company stores (which were famous for over charging workers). The day before, about 20 miners were killed when sheriff's deputies opened fire on them in (AP, 9/11/97)(MC, 9/11/01) 1899 W.E.B. Du Bois (1868-1963) published "The Philadelphia Negro," a sociological study of African Americans in Philadelphia. 1899 The Univ. of Pennsylvania Museum of Archeology and Anthropology opened. (WSJ, 5/7/03, p.D10) 1900 The construction of the rococo City Hall in Philadelphia was completed. The architect was John McArthur Jr. (SFEC, 8/16/98, p.T1) 1900 In Philadelphia, Pa., the 8-million, 110-room Lynnewood Hall, home to the uber-wealthy Widener family, was completed. It came to be called "the last of the American Versailles." French landscape architect Jacques Greber designed the formal French gardens, which were graced by his brother Henri-Louis Greber's fountain of bronze and marble statuary. P.A.B. Widener's son, Joseph, died there in 1943 and the younger generation deemed the property too large to maintain. Much of the acreage was sold to developers and the opulent furnishings were auctioned. In 1952, the Rev. Carl McIntire of Collingswood, N.J., a controversial fundamentalist preacher, bought the property for $190,000 and established a Christian seminary. In 1993 New York physician Richard Sei-Oung Yoon, a former student of McIntire and one-time chancellor of the cash-strapped seminary, bought its mortgage for $1.6 million with plans of establishing his own church there. 1901 Jan 1, The 1st annual Mummers parade was held in Philadelphia. (SFC, 12/31/00, p.A10) 1901 Feb 25, United States Steel Corp. was incorporated by J.P. Morgan Charles Schwab and Andrew Carnegie. Morgan combined Federal Steel and Carnegie Steel to form US Steel. It was the biggest corporate merger of the time. As president of US Steel Schwab acquired the Bethlehem Steel. In 1904 Schwab resigned his position at US Steel to run Bethlehem Steel. (AP, 2/25/98)(WSJ, 1/11/99, p.R42)(WSJ, 5/12/03, p.A6)(WSJ, 10/8/08, p.A15) 1901 Jan 28, Byron Bancroft Johnson announced that the American League would play the 1901 baseball season as a major league and would not renew its membership in the National Agreement. The new league would include Baltimore and Washington, DC, recently abandoned by the National League. The league would also invade 4 cities where National League teams existed: Boston, Cleveland, Detroit and Philadelphia. The 8 charter teams included: the Baltimore Orioles, Boston Americans, Chicago White Stockings, Cleveland Blues, Detroit Tigers, Milwaukee Brewers, Philadelphia Athletics, and Washington Senators. 1901 Jul 15, Over 74,000 Pittsburgh steel workers went on strike. 1901 The first US escalator, manufactured by the Otis Elevator Company, was installed in a Philadelphia office building. It was patented in 1859 and first displayed at the 1900 Paris Exposition. 1901 The Pittsburgh Lamp, Brass & Glass Co. (Pilabrasgo) began operations and continued to 1926. (SFC, 2/21/07, p.G3) 1902 May 10, David O. Selznick, film producer (Gone with the Wind, Rebecca), was born in Pittsburgh, (HN, 5/10/02)(MC, 5/10/02) 1902 May 12, Over 100,000 miners in northeastern Pennsylvania called a strike and kept the mines closed all summer. Owners refused arbitration and Pres. Roosevelt intervened. [see Oct 3] (LCTH, 10/3/99)(SFC, 10/4/02, p.A17) 1902 Jun 9, The 1st Automat restaurant opened at 818 Chestnut Street, Phila. 1902 Oct 3, President Theodore Roosevelt met with miners and coal field operators in an attempt to settle the anthracite coal strike, then in its fifth month. The country relied on coal to power commerce and industry and anthracite or "hard coal" was essential for domestic heating. Pennsylvania miners had left the anthracite fields demanding wage increases, union recognition, and an eight-hour workday. As winter approached, public anxiety about fuel shortages and the rising cost of all coal pushed Roosevelt to take unprecedented action. The meeting failed to resolve differences. A presidential commission awarded the workers a 10% wage increase and a shorter work week. [see May 12] J.P. Morgan came up with a compromise proposal that provided for arbitration and the miners returned to work on Oct 23. p.A17)(AH, 2/03, p.48) 1902 Oct 25, Henry Steele Commanger, American historian, was born in Pittsburg, Pa. He wrote the fifty-five volume "Rise of the American Nation." (HN, 10/25/98)(MC, 10/25/01) 1903 Oct 1, The Pittsburgh Pirates defeated the home team Boston Pilgrims (Red Sox), 7-3, in the first World Series game. Boston, however, went on to win the series, five games to three. 1903 Oct 13, Boston defeated Pittsburgh in baseball’s first World Series. In 2003 Roger I. Abrams authored "The First World Series and the Baseball Fanatics of 1903;" Louis P. Masur authored "Autumn Glory: Baseball's First World Series;" and Bob Ryan authored "When Boston Won the World Series." (WSJ, 7/8/96, p.A8)(HN, 10/13/98)(WSJ, 3/28/03, p.W9)(SSFC, 6/8/03, p.M6) 1903 The 1st trolley with an electric 3rd rail was installed in Scranton, Pa. (SFEC, 9/26/99, p.B8) 1903 Andrew Carnegie donated $1.5 million for the construction of 2 dozen libraries in (Econ, 2/14/09, p.40) 1904 Jan 25, Two-hundred (179) coal miners were entombed in an explosion in Cheswick, Pennsylvania. (HN, 1/25/99)(MC, 1/25/02) 1904 Feb 29, Jimmy Dorsey (d.1957), orchestra leader, was born in Shenandoah, Pa. (HN, 2/29/00)(AP, 2/29/04) 1904 Dec 10, Charles M. Schwab incorporated a revamped Bethlehem Steel. As president of US Steel he had acquired the Pennsylvania steel maker in 1901. Schwab resigned his position at US Steel to run Bethlehem Steel. In 2008 Kenneth Warren authored “Bethlehem Steel: Builder and Arsenal of America." (WSJ, 10/8/08, p.A15) 1905 Jan 31, John O'Hara, novelist (Appointment at Samarra), was born in Pottsville, Penn. (SSFC, 8/31/03, p.M2) 1905 Jun 11, Pennsylvania Railroad debuted the fastest train in world (NY-Chicago in 18 hrs). 1905 Jun, In Pittsburgh, Penn., the world's 1st theater geared exclusively for motion pictures (SFC, 9/28/99, p.A27) 1905 Nov 19, Tommy Dorsey, band leader, was born in Shenandoah, Pa. 1905 Dec 7, Leonard H. Goldenson (d.1999), later chief of ABC broadcasting, was born in (SFC, 12/28/99, p.B3) 1906 Apr 16, In Pennsylvania 3 men were shot dead in a riot among striking coal miners at Windber. An appeal was made to Gov. Pennypacker for troops. (SFC, 4/17/06, p.A9) 1906 Jul 17, American playwright Clifford Odets was born in Philadelphia. 1906 Oct 22, 3000 blacks demonstrated and rioted in Philadelphia. 1906 Dec 27, Oscar Levant, American composer and actor, was born in Pittsburgh. 1906 The Capital building in Harrisburg, Pa., featured a dome modeled on St. Peter’s in Rome. (SSFC, 4/13/03, p.D6) 1906 The John C. Bell building was completed in Philadelphia, Pa. It was later listed on the National Register of Historic Places. (SFC, 1/13/14, p.A4) 1907 May, The idea of a day set apart every year to honor motherhood is credited to Anna Jarvis of Philadelphia, who, in 1907, suggested the wearing of carnations on the second Sunday in May to honor mothers. Her enthusiastic campaign for a nationwide observance attracted enough public support that President Woodrow Wilson issued a proclamation designating the second Sunday in May 1914 the first national Mother’s Day. 1907 Dec 19, A gas explosion killed 239 workers in a coal mine in Jacobs Creek, Pa. (AP, 12/19/97)(MC, 12/19/01) 1907 Dec 23, The 1st all-steel passenger railroad coach was completed at Altoona, Pa. 1907 Dec 24, I.F. Stone (d.1989), American investigative journalist, was born in Philadelphia. "Those who nobly set out to be their brother's keeper sometimes end up by becoming his jailer. Every emancipation has in it the seeds of a new slavery, and every truth easily becomes a (AP, 10/17/99)(AP, 12/24/07) 1907 Milton Hershey, chocolate tycoon, opened Hershey Park, an admission-free amusement park in (SSFC, 4/13/03, p.D6) 1907 Clayton S. Reaser purchased a 5-year old Pennsylvania furniture company named Gettysburg Manufacturing Co. and renamed it Reaser Furniture (SFC, 1/10/07, p.G2) 1907 Charles B. Gillespie, physician and artist, died in Pennsylvania. He had traveled to California during the gold rush and made a number of sketches, including depictions of Sutter’s Mill, some of which he turned into paintings upon returning to Freeport in 1851. In 2008 119 pen-and-ink sketches and 5 oil paintings were put up for auction. (SSFC, 11/23/08, p.B9) 1908 May 10, The first Mother’s Day observance took place during church services in Grafton, W.Va., and Philadelphia. In 1997 Anna Jarvis of Philadelphia first proposed the idea that all mothers wear a carnation on the 2nd Sunday of May. (AP, 5/10/97)(SFC, 9/30/99, p.E5) 1908 May 20, Jimmy Stewart, actor, was born in Indiana, Pa. He is best remembered for his roles in "It's a Wonderful Life" and "Mr. Smith Goes to Washington." (WSJ, 5/20/97, p.A18)(HN, 5/20/99)(AP, 5/20/08) 1908 Nov 18, Imogene Coca d.2001), later co-star with Sid Caesar of the 1950s "Your Show of Shows" TV program, was born in Philadelphia. (SSFC, 6/3/01, p.A29)(AP, 11/18/08) 1908 Nov 28, 154 men died in a coal mine explosion at Marianna, Pa. 1908 In Pennsylvania the Rotunda Building in Philadelphia opened as the Girard Trust. It was built as a replica of the Pantheon in Rome. In 2000 it was converted from a bank into a Ritz-Carlton Hotel. (SSFC, 5/25/14, p.P4) 1908 The Univ. of Pittsburgh introduced the 1st football jerseys with numbers on the back. (SFC, 10/1/99, p.B6) 1909 Nov 13, In Pennsylvania the Cherry Mine disaster killed 259 men and boys. In 2002 Karen Tintori authored “Trapped: The 1909 Cherry Mine Disaster." 1909 Dec 14, The Labor Conference in Pittsburgh ended with a "declaration of war" on U.S. 1909 Harry V. Warehime established Hanover Pretzel Company in Pennsylvania with a single recipe, Hanover Olde Tyme Pretzels. 1909 In Hershey, Pennsylvania, Milton Hershey and his wife Catherine established the Milton Hershey School for the "maintenance, support and education of as many poor, white orphan boys as it could afford." The racial restriction ended in 1970. By 2002 the 1200-student school had an endowment of some (WSJ, 8/12/99, p.A1)(SFC, 7/26/02, p.B3) 1909 The Pittsburgh Pirates, led by pitcher Honus Wagner, defeated the Detroit Tigers 4-3 in the World Series. This marked the last world series appearance by Ty (SFC, 10/2/99, p.A20) 1910 May 23, Franz Kline (d.1962), American painter of abstract expressionist style, was born in Wilkes-Barre, Pa. 1910 Aug 15, Hugo Winterhalter, composer, was born in Wilkes-Barre, Pennsylvania. 1910 Nov 27, In NYC the Pennsylvania Railroad began service at Pennsylvania Station. It was begun under the direction of PRR president Alexander J. Cassatt (d.1906) and designed by the architectural firm of McKim, Mead and White. In 2007 Jill Jonnes authored “Conquering Gotham: A Gilded Age Epic: The Construction of Penn Station and its Tunnels." Penn Station was demolished in 1963. (AP, 11/27/06)(Econ, 4/14/07, p.95)(SSFC, 7/8/07, 1910 Dec 19, Rayon was 1st commercially produced by Marcus Hook in Penn. 1910 In Philadelphia John Wanamaker’s The Grand Depot department store, was replaced by a 250-foot tall, 12-story edifice known as Wanamaker’s. (ON, 12/05, p.6) 1911 Oct, The Philadelphia Athletics, forerunners of the Oakland A’s, won the World Series, beating the New York Giants of the National League, today’s SF (SMTS, 10/1/86, p.4) 1912 May 18, Richard Brooks, director (Blackboard Jungle, In Cold Blood), was born in 1912 Aug 23, Gene Kelly, dancer and actor who starred in "An American in Paris" and "Singing in the Rain," was born in Pittsburgh, Pennsylvania, as Eugene Curan. Kelly debuted on Broadway in 1938 musical "Pal Joey" and in the film "For Me and My Gal" four years later (HN, 8/23/98)(MC, 8/23/02) 1912 Nov 9, The football team of Pennsylvania’s Carlisle Indian School, with running back Jim Thorpe, defeated the Army team, with Dwight D. Eisenhower as linebacker, 27-6. In 2007 Sally Jenkins authored “The Real Americans: The Team That Changed a Game, a People, a Nation." 1912 Engraver George T. Morgan is believed to have produced 5 Liberty Head V nickels at the Philadelphia Mint with a 1913 stamped date. In 2004 one sold for $3 (WSJ, 5/20/04, p.C1)(SFC, 4/27/13, p.A4) 1912-1938 Leopold Stokowski was the music director of the Philadelphia Orchestra. (Hem, 6/96, p.107)(WSJ, 2/11/99, p.A24) 1913 May 18, Perry Como (Pierino Roland Como, d. 2001), singer, was born in Canonsburg, Pa. (SSFC, 5/13/01, p.A27) 1913 Dec 1, The first drive-in automobile service station, built by Gulf Refining Co., opened in Pittsburgh. [see Cincinnati in 1912] 1913 In Pennsylvania a fire at the Red Ash colliery ignited a coal mine. As of 2009 it was still burning and was the oldest of 36 ongoing mine fires. (Econ, 3/14/09, p.34) 1914 Apr 19, Charles Sanders Peirce (b.1839), American polymath, philosopher and scientist, died in Milford, Pa. In 1883 he used randomization in a psychological experiment at Johns Hopkins Univ. 1914 John Wanamaker (1838-1922), Philadelphia retailer and former US Postmaster General (188901893), dispatched 2,000 tons of food aid to Belgium. (https://en.wikipedia.org/wiki/John_Wanamaker)(Econ., 5/9/20, p.21) 1915 Geisinger Health Systems was founded in Pennsylvania. (Econ, 6/18/11, p.75) 1916 Jul 28, Laird Cregar, actor (Charley's Aunt, Hangover Square), was born in Phila. 1916 The Mercer Museum in Doylestown was completed by Henry Chapman Mercer (1856-1930), archeologist and collector. (AH, 4/01, p.18) 1916 Charles Taze Russell (b.1852) died. He founded the International Bible Students Association. In the 1870’s Russell abandoned the Adventist movement and formed his own in Pennsylvania, which was later named Jehovah’s Witnesses. His early followers were called "Russellites." 1917 Apr 10, A munitions factory explosion at Eddystone, PA., killed 133 workers. 1917 Jul 12, Andrew Wyeth, painter who focused on the northeastern United States, was born in Chadds Ford, Pa. In 1998 Beth Venn and Adam Weinberg published "Unknown Terrain," a companion piece to a Whitney Museum exhibition of his art. (HN, 7/12/98)(MC, 7/12/02)(www.wyethcenter.com) 1917 Sep 26, Australian Private Thomas Hurdis (26) was wounded in Belgium, and died on Oct. 3 in a US field hospital in France. His skull with a bullet lodged in bone between his eyes was later put on display at the Mutter Museum of The College of Physicians of Philadelphia. On July 20, 2018, the skull was buried in Hurdis' grave at the French Mont Huon Military Cemetery in Le Treport in a ceremony attended by Hurdis' family and 1917 Oct 22, Leopold Stokowski led Philadelphia Orchestra in its first recording. 1917 Theresa Bernstein, artist, helped found the Philadelphia Ten, a female art group. It was created in response to the Eight, a male-dominated group later called the Ashcan School. (SFC, 3/1/01, p.E2) 1917 John G. Johnson, Philadelphia lawyer, died and left to the city a collection in his home of Renaissance art. Within 20 years the collection was taken over by the Pennsylvania Museum of Art. (WSJ, 7/18/03, p.W18) 1918 May 18, A TNT explosion in chemical factory in Oakdale, PA, killed 200. 1918 Jul 25, A race riot in Chester, Pennsylvania, left 3 blacks and 2 whites dead. 1918 Sep 28, In Pennsylvania a parade to sell war bonds resulted in an epidemic of the “Spanish flu" that caused mass death in Philadelphia. 1918 Milton Hershey endowed the Milton Hershey School with $60 million in stock. (WSJ, 8/12/99, p.A1) 1918 The influenza epidemic killed 11,000 people in Philadelphia. (LSA, Fall/06, p.58) 1919 Feb 18, Jack Palance (d.2006), later film and TV star, was born as Volodymir Ivanovich Palahniuk in Latimer Mines, Pa. (SFC, 11/11/06, p.B6) 1919 Nov 17, Hershy Kay, composer and arranger, was born Philadelphia, Penn. 1920 Jan 15, John J. "Cardinal" O'Connor, Roman Catholic Archbishop of NY, was born in Philadelphia. 1920 Nov 2, The first radio broadcast of presidential elections in the United States was made by radio. Westinghouse had built radio station KDKA on its factory roof in Pittsburgh and was among the first to broadcast returns from the Harding-Cox presidential election. 8MK, the first US station owned by a newspaper (the Detroit News), also broadcast the election 1/12/98, p.A19)(HN, 11/2/98)(AP, 11/2/99) 1920 Nov 25, The 1st Thanksgiving Parade was held in Philadelphia. 1921 Jan 2, Religious services were first broadcast on radio when KDKA aired the regular Sunday service of Pittsburgh's Calvary Episcopal Church. 1921 Jan 31, Mario Lanza (d.1959), actor, singer (Great Caruso, Toast of New Orleans), was born in Philadelphia. 1921 Mar 6, Police in Sunbury, Penn., issued an edict requiring Women to wear skirts at least 4 inches below the knee. 1921 May 10, Nancy Walker, Bounty ads, actress (Rhoda, McMillan & Wife), was born in 1921 Aug 5, The first radio broadcast of a baseball game took place in Pittsburgh. (WSJ, 10/15/98, p.B8) 1921 Aug 20, Jacqueline Susann, author (Valley of the Dolls), was born in Phila., Pa. 1921 Aug 21, Nancy Kulp, actress (Jane-Beverly Hillbillies), was born in Harrisburg, Pa. 1921 Nov 3, Charles Bronson (d.2003), [Buchinsky], actor (Death Wish, Dirty Dozen), was born in (SFC, 9/1/03, p.A2) 1921 Baldwin Locomotive Works in Philadelphia built Engine 2472. In 1975 it was acquired for the San Mateo Fairgrounds in California. (SSCM, 12/2/01, p.15) 1922 Aug 26, The Philadelphia Phillies beat the Chicago Cubs 26-23. (SFEC, 7/25/99, Z1 p.2) 1922 Dec 12, John Wanamaker (b.1938), US merchant who founded a chain of stores in Philadelphia, died. He introduced department stores and price tags to the US and became the first modern advertiser when he bought ads in newspapers to promote his stores. p.61)(Econ, 7/15/06, p.15) 1922 Mennonites from Canada and Pennsylvania fled persecution and settled near Chihuahua, Mexico. (SFEC, 6/1/97, p.T3)(SFEC, 11/5/00, p.T4) 1923 Jul 10, Jean Kerr (d.2003), playwright and author, was born in Scranton, Pa. Her later books included "Please Don’t Eat the Daisies." (SFC, 1/7/03, p.A22) 1924 In Philadelphia, Pa., the 18-story Philadelphia Inquirer building was completed as home for the Philadelphia Inquirer newspaper. (WSJ, 8/29/07, p.B1) 1925 Jun 25, Robert Venturi, architect (Levittown NY, Las Vegas), was born in Phila. 1925 Dr. Albert C. Barnes (1872-1951) built a mansion to house his collection of French impressionist and post-impressionist masterpieces in Merion, Pennsylvania. The collection grew to some 2,500 objects and their setup and access was highly restricted by Dr. Barnes’ trust indenture. Barnes had made his fortune with a pediatric antibiotic called Argyrol. By 2000 his foundation was broke. In 2003 John Anderson authored ""Art Held Hostage," an account of the Barnes (WSJ, 11/28/95, p.A-12)(WSJ, 7/18/03, p.W18) 1925 The Pottsville Maroons beat the Chicago Cardinals for the NFL championship, but lost it on a technicality after they played a college all-star team in (Econ, 11/1/03, p.30) 1926 Sep 23, Gene Tunney (1897-1978), an ex-marine, defeated Jack Dempsey for the World Heavyweight Boxing championship in Philadelphia. Tunney defeated Dempsey again in a 1927 rematch and retired undefeated in 1928. In 2006 Jack Cavanaugh authored “Tunney: Boxing’s Brainiest Champ and His Upset of the Great Jack Dempsey." (Smith., 5/95, p.12)(SFC, 10/19/99, p.A22)(WSJ, 1926 Oct 13, Ray Brown (d.2002), jazz bass player, was born in Pittsburgh. (HN, 10/13/00)(SFC, 7/4/02, p.A21) 1927 Feb 2, Stan Getz, jazz saxophonist, was born in Philadelphia. (SFC, 12/28/99, p.C4) 1927 Mar 11, The 1st armored commercial car hold-up in US took place in Pittsburgh. 1927 Sep 17, George Blanda, NFL kicker and quarterback (Bears, Oilers, Raiders), was born in 1927 Elsie Driggs created her (WSJ, 4/9/98, p.A21) 1928 Mar 20, Fred Rogers, television performer (Mr. Roger's Neighborhood), was born in 1928 May 19, "Firedamp" exploded in Mather, Pa. coal mine killing 195 of 273 miners. (DT internet 5/19/97) 1928 Nov 2, L. Stokovski conducted the premiere of Dmitri Shostakovitch's 1st Symphony, in 1928 Andy Warhol (d.1987) was born in Pittsburgh. He went to school there and graduated from the Carnegie Institute of Technology. (SFEC, 8/13/00, p.T11) 1928 Walter E. Diemer (23), an accountant for Fleer Chewing Gum in Philadelphia, began testing recipes for a gum base. He invented the first batch of bubble gum, making it pink because that was the only shade of food coloring on hand. It was sold under the Dubble Bubble name for a penny. (SFC, 1/13/98, p.A19)(SFC, 8/2/99, p.A22) 1929 In Pennsylvania the Rodin Museum opened in Philadelphia. In 2012 it re-opened following a 3-year, $9 million restoration. (SFC, 7/13/12, p.A8) 1929 Lefty O’Doul hit .398 becoming the National League batting champ of the Philadelphia Phillies. He went on to manage the San Francisco Seals and in 1958 opened Lefty’s, a bar in San Francisco. (SFC, 3/5/96, p.C1)(SFC, 7/18/97, p.A9)(SSFC, 1930 Mar 17, James Benson Irwin, Col. USAF, astronaut (Apollo 15), was born in Pittsburgh, 1930 Jun 2, Charles Conrad (d.1999), astronaut, was born in Philadelphia. He walked on the moon during the Apollo XII mission in 1969. (SFC, 7/9/99, p.A6) 1930 In Philadelphia, Pa., Pat’s King of Steak’s opened at Ninth and Passyunk Ave. They helped make famous the Philadelphia cheese steak sandwich. (SSFC, 9/17/06, p.G5) 1930s Hubley Manufacturing of Lancaster, Pa., made cast-iron toys that later became valued as collectibles. The Arcade Manuf. Co. of Freeport, Ill., also made (SFC, 1/28/98, Z1 p.3) 1931 Jan 20, Gifford Pinchot (1865-1946) began serving a 2nd term as the 28th governor of Pennsylvania and continued to 1935. His first term was from 1923-1927. Following the of Prohibition in 1933, Pinchot kept restrictions on the sale of alcohol. (Econ, 3/30/13, p.34) 1931 Apr 7, Donald Barthelme (d.1989), US writer, was born in Philadelphia. (http://en.wikipedia.org/wiki/Donald_Barthelme)(WSJ, 2/21/09, p.W8) 1932 Apr 4, Vitamin C was 1st isolated by C.C. King at the Univ. of Pittsburgh. 1932 Jul 25, Paul J. Weitz, astronaut (Skylab 2, STS 6), was born in Erie, Pennsylvania. 1933 Mar 7, George Darrow added some copyrighted art work to the board game Monopoly and began selling it commercially in Philadelphia. He sold it to Parker Brothers in 1934. The game had originally been patented in 1904 as the Landlord’s Game by Elizabeth J. Magie. In Oct 1929 Ruth Hoskins brought a version to Atlantic City, refined the rules and street names. It was later introduced to George Darrow. 1933 Mar 31, Shirley Jones, actress (Partridge Family, Elmer Gantry), was born in Smithton, Pa. 1933 May 7, Johnny Unitas (d.2002), the son of Lithuanian immigrants, was born in Pittsburgh, Pa. He became a NFL Quarterback for the Baltimore Colts and San Diego Chargers. He was voted into the Pro Football Hall of Fame in 1933 Nov 7, Pennsylvania voters overturned blue law, by permitting Sunday sports. 1933 Dec 21, Dried human blood serum was 1st prepared at the Univ. of Pennsylvania. 1933 Hugh J. Ward author a rule book on Bingo. He had standardized the modern game at carnivals in and around the Pittsburgh and Western Pennsylvania areas in the early 1920's and went on to copyright the name. 1933 In Pennsylvania the Pymatuning Dam impounded the Pymatuning Reservoir. It was constructed to regulate the flow of the Shenango and Beaver rivers. The reservoir later became a major attraction for tourists, who came to feed the local carp. (www.dnr.state.oh.us/parks/parks/pymatuning.htm)(WSJ, 6/16/07, p.A1) 1933 Milton Hershey, chocolate tycoon, opened Hotel Hershey in Hershey, Pa. (SSFC, 4/13/03, p.D6) 1933 Art Rooney founded the Pittsburgh Pirates football team for $2,500. (WSJ, 7/8/08, p.A17) 1934 Feb 17, 1st high school auto driving course was offered by State College, Penn. 1934 Jun 27, Anna Moffo, soprano (Lucia, Traviata), was born in Wayne, Penn. 1934 Aug 24, In Philadelphia, Pa., Philo T. Farnsworth (28), a San Francisco scientist, produced a televised picture of the moon, the first recorded use of television (SSFC, 8/16/09, p.46) 1934 Pennsylvania passed legislation to limit alcohol consumption and protect the state's brewers from outside competition. (WSJ, 3/23/04, p.B5) 1935 Feb 10, Pennsylvania RR began passenger service with new electric locomotive. 1935 Apr 21, Charles Grodin, actor, Woman in Red, Lonely Guy, Heartbreak Kid), was born in 1935 Dec 4, Some 1,200 at St Joseph's College, Philadelphia, enrolled in an anticommunism class. 1935 The Pittsburgh Crawfords were considered to have been the greatest Negro League baseball team of all time. (SFEC, 4/12/98, p.T4) 1936 Jun 11, Presbyterian Church of America was founded at Philadelphia. 1936 Aug 21, Wilt Chamberlain (d.1999 at age 63), later basketball star, was born in Philadelphia. From 1952-1955 he led Overbrook High School to a 56-3 record. (SFC, 10/13/99, p.D4) 1936 Aug, Pres. Franklin Delano Roosevelt accepted his re-nomination and gave his "rendezvous with destiny" speech in Philadelphia. (SFEC, 7/30/00, p.C17) 1936 Frank Lloyd Wright designed the Fallingwater house near Mill Run in Western Pennsylvania. He was warned by structural engineers that there was not enough support for the cantilevered floors, but dismissed their warnings. Sag began immediately after construction and in 1997 steel support beams were added as a temporary measure. Edgar Kaufmann Jr. later published "Fallingwater, A Frank Lloyd Wright House." (WSJ, 10/24/97, p.B18)(SFEC, 2/20/00, p.T10) 1936 Moses Annenberg bought the Philadelphia Enquirer, a reputed bible of Republican politics. (SFC, 10/2/02, p.A2) 1936 A major flood hit Pittsburgh. Pennsylvania soon passed a 10% tax on alcohol in an emergency measure to help cover the flood damage. Repairs were completed in about 5 years, but the tax remained and was later increased twice to 15% and then 18%. (WSJ, 6/29/99, p.A1)(WSJ, 8/15/08, p.A11) 1938 Jun 24, A 500 ton meteorite landed near Pittsburgh. 1938 Jul 4, 1st game at Shribe Park, Phila; Braves beat Phillies 10-5. 1938 Jul 14, Owen Wister (b.1860), novelist, died. His 1902 novel "The Virginian" inspired 5 films. He had earlier begun a novel set in his native Philadelphia but stopped work on it when his wife died during childbirth on Aug 24, 1913. (HN, 7/14/01)(SFC, 1/9/02, p.D8) 1938 Nov 8, Crystal Bird Fauset of Pa., became the first African American woman to be elected to a 1938 Tennessee Williams wrote his play "Not About Nightingales." It was based on an incident in Pennsylvania's Philadelphia County prison, where 4 inmates died after 25 inmates, who threatened a hunger strike due to bad food, were locked in an isolation chamber with giant radiators pumping (WSJ, 3/3/99, p.A17) 1938 Byron White signed a $15,800 contract with the Pittsburgh Pirates becoming the NFL’s first big money player. He later served for 31 years as a US Supreme (WSJ, 7/8/08, p.A17) 1939 Jun 6, In Pennsylvania the first Little League baseball game was played. The league was founded by Carl Stotz in Williamsport. The Little League World Series began in 1947. Girls were banned from 1951-1974. (SSFC, 6/1/14, Par. p.8) 1939 Aug 11, Moses Annenberg, owner of the Philadelphia Enquirer, was indicted by a federal jury in Chicago for evading some $3.2 million in income taxes. (SFC, 10/2/02, p.A2) 1939 St. John Terell (d.1998 at 81), actor and impresario, founded the Bucks County Playhouse in New (SFC, 10/21/98, p.C3) 1939 Jim Rex founded the Ranger Joe Breakfast Food Co. in Philadelphia. It was sold in the 1940s to Philadelphia businessman Moses Berger and sold again in 1954 to Nabisco and renamed "Wheat and Rice Honeys." (SFC,11/19/97, Z1 p.7) 1939 Latrobe Brewing of Latrobe, Pa., began making Rolling Rock, a pale lager. It was later acquired by InBev SA. In 2006 Rolling Rock was acquired by Anheuser-Busch, which moved operations to Newark NJ. In 2008 Anheuser-Busch was acquired by InBev SA. 1940 Apr 20, RCA publicly demonstrated its new and powerful electron microscope in (AP, 4/20/97)(HN, 4/20/98)(MC, 4/20/02) 1940 Jun 24, The Republican Convention, opened in Philadelphia. In 2005 Charles Peters authored “Five Days in Philadelphia." An account of the convention and how it freed FDR to move against Hitler. (WSJ, 7/6/05, p.D10)(http://tinyurl.com/e3xrw) 1940 Jun 28, The Republican Convention, held in Philadelphia, nominated Wendall Willkie (d.1944) for US president on 6th ballot. Senator Charles L. McNary from Oregon was his running mate. They were defeated by President Franklin Roosevelt who won his third term. In 2005 Charles Peters authored “Five Days in Philadelphia." An account of the convention and how it freed FDR to move against Hitler. (WSJ, 7/6/05, p.D10)(SFEC, 7/30/00, 1940 Oct 1, The first section of the Pennsylvania Turnpike, 160 miles in length, was opened to the 1940 Oct 24, F. Murray Abraham, actor (Amadeus, Mad Man), was born in Pittsburgh, Pa. 1940 Nov 1, 1st US air raid shelter was made in Fleetwood, Pa. 1940 Art Rooney renamed the Pittsburgh Pirates football team to the Pittsburgh Steelers. (WSJ, 7/8/08, p.A17) 1940-1953 John W. Nason (d.2001 at 96) served as president of Swarthmore College. From 1942-1945 he served as chairman of the National Japanese American Student Relocation Council and helped over 3,000 students out of detention camps and into institutions of higher learning. (SFC, 11/24/01, p.A21) 1941 May 26, American Flag House, the Betsy Ross Home, was given to the city of Phila. 1941 Aug 28, Paul Peter Plishka, bass (Met Opera), was born in Old Forge, Penn. 1941 Matt Cvetic (d.1962 at 53) infiltrated the Communist party in Pittsburgh. The 1951 film "I Was a Communist for the FBI" was based on his true story. In 2001 Daniel J. Leab authored "I Was a Communist for the FBI." (WSJ, 2/12/00, p.A25) Jan 10, Jim Croce, (d.1973) rock vocalist (Time in a Bottle, Workin' At The Car Wash Blues), was born in Philadelphia. 1942 Mar 26, 20 tons of gelignite killed 21 in a stone quarry in Easton, PA. 1942 Nov 20, Joseph Biden, later US Senator for Delaware, was born in Scranton, Pa. In 2008 Barack Obama named Biden as his vice presidential running mate. (SSFC, 8/24/08, p.A15) 1942 Moses Annenberg, owner of the Philadelphia Enquirer, died. His son Walter took over as editor (SFC, 10/2/02, p.A2) 1943 May 31, Joe Namath, NFL QB (NY Jets), $400,000 man (1969 Superbowl), was born in PA. 1943 Jun 17, Newt Gingrich, later Republican Speaker of the House (1995-1998), was born in (SFC, 11/7/98, p.A4) 1943 Richard James (d.1974) observed a torsion spring balance bounce off a ship’s deck while working at a Philadelphia shipyard and conceived the idea of a "slinky" toy for children, named by his wife Betty James (d.2008). In 1945 they founded James Industries. In 1998 the company was sold to POOF Products of Michigan. (IBCC, 10/97, #9)(SSFC, 11/23/08, p.B9) 1944 Jan 28, Leonard Bernstein's "Jeremiah," premiered in Pittsburgh. 1946 Jul 6, Jamie Wyeth, artist (An American Vision-Boston), was born in Pennsylvania. 1947 Feb 9, Bank robber Willie Sutton escaped jail in Philadelphia. 1947 Sep 13, WPVI TV channel 6 in Philadelphia, PA., (ABC) began broadcasting. 1948 Feb 14, Winthrop Rockefeller (1912-1973), later governor of Arkansas (1967-1971), married Barbara Sears (1916-2008), the Pennsylvania-born daughter of Lithuanian immigrants. They had one child, Winthrop Paul Rockefeller, but the marriage dissolved in a high-profile divorce in 1954. Barbara Bobo Rockefeller, born as Jievute Paulekiute in Noblestown, Pa., was featured as Miss Lithuania at the 1933 Chicago World's Fair. She later was known as Eva Paul. 1948 Jun 2, Albert Innaurato, playwright, director (Age in Soho), was born in Phila. 1948 Jun 17, A United Air Lines DC-6 crashed near Mount Carmel, Penn., killing all 43 people on 1948 Jun 21, The Republican national convention opened in Philadelphia. The delegates ended up choosing Thomas E. Dewey to be their presidential nominee. 1948 Jun 24, The Republican National Convention, meeting in Philadelphia, nominated New York Governor Thomas E. Dewey for president. 1948 Jun 25, The Republican national convention in Philadelphia chose California Gov. Earl Warren to be Thomas E. Dewey's running mate. 1948 Jul 12, The Democratic national convention opened in Philadelphia. 1948 Jul 15, President Truman was nominated for another term of office by the Democratic National Convention in Philadelphia. 1948 Jul 24, Henry A. Wallace accepted the presidential nomination of the Progressive Party in 1948 Oct 31, By this date some 20 people died and 6,000 were made ill by smog from steel and zinc plants in Donora, Pennsylvania. Between October 26 and October 31, 1948, an air inversion trapped fluoride effluent from the Zinc Works. In three days, 18 people died. After the inversion lifted, another 50 died. Hundreds more finished the rest of their lives with damaged lungs and hearts. Both plants closed in 1966. In 2002, “When Smoke Ran Like Water" was published by Devra Davis. 1948 The John Murtha Airport opened in Jonestown, Pennsylvania. From 1989-2009 Congressman John Murtha steered some $150,000,000 to the airport. In 2009 there were a total of 18 commercial flights per week, all of which went to Dulles Airport in Washington, DC. (http://tinyurl.com/nsdv8k)(Econ, 1/23/10, p.26) 1949 Jun 16, A gas turbine, electric locomotive was demonstrated in Erie, Pa. 1949 Aug 31, Richard Gere, actor (Breathless, Cotton Club), was born in Phila., Pa. 1949 Pennsylvania enacted a state law requiring the reading of 10 Bible verses each day in schools followed by joint recitation of the Lord's Prayer and the Pledge of Allegiance. (SFC, 11/24/03, p.A18) 1949 There was a cholera outbreak in Philadelphia, Pa. (SFC, 3/8/14, p.C3) 1951 Jun 14, UNIVAC, the first computer built for commercial purposes, was demonstrated in Philadelphia by Dr. John W. Mauchly and J. Prosper Eckert, Jr. 1951 Jun 15, 1st commercial electronic computer was dedicated in Philadelphia. [see Jun 14] 1951 Jul 24, Dr. Albert C. Barnes, eccentric collector of impressionist art, died in an automobile crash. [see 1925 Barnes] His will specified that his art collection be kept forever in Lower Merion Township, Pa. In 2004 a judge allowed trustees to move the collection to Philadelphia. (WSJ, 11/28/95, p.A-12)(SFC, 12/15/04, 1951 Pennsylvania passed a law requiring a loyalty oath from candidates for public office. In 2006 the oath was deemed unconstitutional. (SFC, 8/28/06, p.A3) 1951 Elizabeth Ralph, physicist at the Univ. of Pennsylvania, created the Museum Applied Science Center for Archeology (MASCA). (AM, 11/04, p.30) 1952 Mar 18, The 1st plastic lens for cataract patients was fitted in Phila. 1952 Oct 7, The 1st "Bandstand" broadcast in Philadelphia on WFIL-TV. Dick Clark joined in 1955 as a substitute-host. [see 1956] (SFC, 11/10/99, p.E3)(SFC, 4/15/00, p.D3)(MC, 1952 John J. Rigas founded Adelphia Communications in Coudersport, Pa., with a dream and a $300 check for a local cable franchise. (WSJ, 5/28/02, p.A1)(USAT, 7/9/04, p.3B) 1952 Crigler-Najjar syndrome was named for two doctors who identified it this year. Patients began living longer in the 1970s when doctors realized that the wavelength and energy of blue light changes the nature of the bilirubin, allowing it to be excreted from the body. In 2007 there were about 110 known cases of Crigler's worldwide, including about 35 in the US. About 20 are among the Amish and Mennonite in 1953 Mar 26, Dr. Jonas Salk of the University of Pittsburgh announced that a vaccine against polio had been successfully tested in a small group of adults and children. By April 1955, the vaccine had undergone further testing and gained federal approval for public use, as shown in this photo of Salk administering the vaccine at Colfax School in Pittsburgh. Salk’s polio vaccine was so successful that by 1961 the incidence of polio had decreased by 95 percent. 1954 Feb 23, The first mass inoculation of children against polio with the Salk vaccine began in Pittsburgh. Jonas Salk created the Salk vaccine against polio. It used a killed virus to induce immunization. Poliomyelitis is a viral attack of the central nervous system and can cause paralysis and death by asphyxiation. [see Apr 26] In 2005 David M. Oshinsky authored “Polio: An American Story – The Crusade That Mobilized the Nation Against the 20th Century’s Most Feared Disease." (SFC, 6/21/96, p.A10)(HN, 2/23/98)(AP, 2/23/98)(Econ, 6/18/05, p.79) 1956 Jul 4, Independence National Historical Park formed in Philadelphia. 1956 Dick Clark (27) joined the TV show "American Bandstand" in Philadelphia after one of the 2 original hosts was arrested fro drunk driving. He was replaced by David Hirsch for the last season in 1989. (SFC, 11/10/99, p.E3)(SFC, 5/2/02, p.D1) 1956 Whirling disease infecting the salmon family of fish was first detected in the US in 1956 in Pennsylvania. It was native to Eurasia and caused by a fungus carried in spores hosted by the Tubifex tubifex worm. In 1995 it was detected in Montana fish. (WSJ, 3/26/99, p.W10) 1957 Jan 3, The Hamilton Watch Company was the first to introduce an electric watch in Lancaster, 1957 Aug 5, "American Bandstand," a teenage dance show hosted by Dick Clark (1929-2012) in Philadelphia, made its network debut on ABC-TV. (WSJ, 3/24/97, p.B1)(SFC, 11/10/99, p.E3)(AP, 8/5/07)(SFC, 4/19/12, p.C5) 1957 Aug 21, Kim Sledge, vocalist (Sister Sledge-We are Family), was born in Phila. 1957 Dec 2, The Shippingport Atomic Power Station in Pennsylvania, the first full-scale commercial nuclear facility to generate electricity in the US, went critical. [see July 12] It was taken out of service in 1982. (SSFC, 4/8/07, p.A18)(AP, 12/2/07) 1957 Dec 18, The Shippingport Atomic Power Station in Pennsylvania, the first nuclear facility to generate electricity in the United States, went on line [see July 1957 Bill and Daisy Myers became the first Black couple to buy a house in Levittown (Willingboro), Pa. State police were required to protect them. They lived there until 1961. In 1999 Daisy was given a reception and an apology from the Bristol Township Mayor Sam Fenton. Levittown was created by William Levitt, who kept costs down by bringing in ready made walls and buying appliances directly from manufacturers. In 2009 David Kushner authored “Levittown: Two Families, One Tycoon, and the Fight for Civil Rights in America’s Legendary Suburb." (SFC, 12/9/99, p.A6)(Econ, 5/31/08, p.28)(WSJ, 1957 Dr. Hilary Koprowski of the Wistar Institute in Philadelphia developed an oral polio vaccine and tested it in Africa (Congo). The Wister polio vaccine was given to some 300,000 people in the Belgian Congo from 1957-1960. A later theory held that reuse of needles during the immunization program caused AIDS via “serial passage" that transformed the SIV virus into HIV. In 1999 Edward Hooper authored “The River," a detailed hypothesis for the origin of AIDS in Africa. Hooper suspected that the Wister polio vaccine, produced from monkey kidney cells, contained SIV virus. In 2000 a computerized study indicated that the AIDS virus was introduced to humans about 1930. (SFC, 2/2/00, p.A19)(SFC, 1/15/01, p.A11)(SFC, 1958 The Hearst Corp. launched (SFC, 8/7/99, p.A9) 1959 The Rev. Willie James launched a lawsuit that led to the desegregation of Willingboro (Econ, 5/31/08, p.29) 1959 Bassetts produced 50 tubs of borscht sorbet in honor of Premier Nikita Khrushchev’s visit to (WSJ, 8/1/00, p.A24) 1959 Mario Lanza (b.1921) died in Italy at age 38. He was born as Freddy Cocozza in South Philly. A museum dedicated to the Italian singer is tucked inside of the Settlement Music School of Philadelphia. (Smith., 4/1995, p.95)(SFEC, 3/21/99, DB p.9) 1960 Jul 4, The 50-star flag made its debut in Philadelphia. A 50th star was added to the American flag in honor of Hawaii's admission into the Union on August 21, 1959. (HN, 7/4/98) (IB, Internet, 12/7/98) 1960 Aug 23, Broadway librettist Oscar Hammerstein II (65) died in Doylestown, Pa. 1960 Oct 13, The Pittsburgh Pirates won the World Series at Forbes Field with a 9th inning homerun by Bill Mazeroski. A Univ. of Pittsburgh academic building was later built on the site. (WSJ, 3/25/04, p.D1) 1960 A mutated gene on the "Philadelphia chromosome" was found to be responsible for chronic myelogenous leukemia. It caused white blood cells to divide (WSJ, 6/6/00, p.A1) 1962 Feb 26, Wilt Chamberlain of NBA Philadelphia Warriors scored 67 points vs. New York. 1962 Mar 5, The US Supreme Court in Griggs v. Allegheny County ruled that airports must compensate people living in the near vicinity for noise and 1962 Mar 10, The Phillies baseball club left the Jack Tar Harrison Hotel due to its refusal to admit black players, and moved to Rocky Point Motel, 20 miles outside Clearwater, Florida. 1962 Jul 28, 19 died in a train crash in Steelton, Pa. 1962 The Philadelphia Warriors basketball franchise with star Wilt Chamberlain moved to the SF Bay (SFC, 10/13/99, p.D4) 1962 Walter Annenberg, owner of the Philadelphia Enquirer, established the M.L. Annenberg School for Communication at the Univ. of Pennsylvania. (SFC, 10/2/02, p.A2) 1962 A fire broke out in a garbage dump above an abandoned coal mine in Centralia, Pen. The property had been deeded to the town in 1954 for $1. The fire spread and burned for years. In 1983 US Congress approved $42 million to help the residents move, and by 2005 only about a dozen residents remained. In 2007 Joan Quigley authored “The Day the Earth Caved In: An American Mining Tragedy." (WSJ, 4/17/07, p.D6) 1963 Jun 17, The US Supreme Court ruled 8-1 to strike down rules requiring the recitation of the Lord's Prayer or reading of Biblical verses in public schools. The case began in 1956 when Edward L. Schempp (d.2003), on behalf of his son, objected to a 1949 Pennsylvania law requiring 10 Bible verses each day followed by the Lord's Prayer and the Pledge of Allegiance. (AP, 6/17/97)(HN, 6/17/98)(SFC, 11/24/03, p.A18) 1963-1976 Albert W. Johnson (d.1998 at 92) served in the US Congress. He was elected to the Pennsylvania House of Representatives in 1946. (SFC, 9/7/98, p.A21) 1964 Aug 28, Race riots took place in Philadelphia. 1964 Nov 3, Philadelphia voters approved $25 million to build a new sports stadium. 1964 Roger Abrahams (1933-2017), American folklorist, authored “Deep Down in the Jungle: Negro Narrative Folklore from the Streets of Philadelphia." (SSFC, 7/2/17, p.C8) 1964 Stefan Lorant (1901-1997), Hungarian-born filmmaker and writer, authored "Pittsburgh: the Story of an American City." He wrote the book following a chance meeting with Edgar Kaufman, the Pittsburgh department store mogul. 1965 Jan 13, The SF Warriors traded Wilt Chamberlain to the Philadelphia 76ers for three players and a reported $3 million in cash. The 76ers assumed Wilt’s $65,000 (SSFC, 1/11/15, DB p.42) 1965 Sep 10, Father Divine (b.~1876), African-American preacher, died in Philadelphia. His full self-given name was Reverend Major Jealous Divine, and he was also known as "the Messenger" early in his life. He founded the International Peace Mission movement, formulated its doctrine, and oversaw its growth from a small and predominantly black congregation into a multiracial and international church. Due to his ideology, many consider him to be a cult leader. 1965 The American Conservatory Theater was founded by William Ball in 1965 in Pittsburgh. ACT moved west and settled in at the Geary Theater in SF in 1967. (SFEC, 3/8/98, p.W29) 1965 Richard Scaife (1932-2014) of Pittsburgh, heir to the Mellon banking fortune, inherited $500 million. With more family bequests, income from trust funds and investments he nearly tripled his net worth over his lifetime. (SFC, 7/5/14, p.C4) 1967 Mar 7, Convicted Teamster boss Jimmy Hoffa began an eight-year prison term at Lewisburg Federal Prison in Pennsylvania for defrauding the union and jury tampering. The sentence was commuted by President Nixon Dec 23, 1967 May 6, 400 students seized the administration building at Cheyney State College, Pa. 1968 Feb 1, The Pennsylvania Railroad and NYC Central merged into Penn Central. 1968 Sep, The Big Mac was created by McDonald’s franchisee Jim Delligatti in Pittsburgh. It sold for 49 cents. (SFC, 9/10/98, p.B2) 1968 Oct 1, The cult horror movie "Night of the Living Dead" had its world premiere in 1968 The Delfonics soul singing group of Philadelphia recorded their hit "La-la Means I Love You." (SFEC, 1/25/98, DB 1969 Jul 21, Riots in York, Pa., left 2 people dead, Lillie Belle Allen (27) along with rookie officer Henry Schaad (22). Schaad was mortally wounded 3 days before Allen was killed. Over 60 people were arrested as one city block burned. In 2001 Arthur (47) and Robert Messersmith (52) were arrested for the slaying of Allen. In 2001 Rick Lynn Knouse (48) and Gregory Henry Neff (53), former members of the Girarders white street gang, were also charged in the murders. In 2001 York Mayor Charles Robertson was arrested on homicide charges for allegedly handing out ammunition to white gang members and exhorting them to "Kill as many niggers as you can." In 2001 Thomas P. Smith was accused in the ambush shooting of Allen. In 2001 Stephen Freeland (49) and Leon Wright (53) were charged in the murder of officer Schaad. Robertson was acquitted in 2002. Messersmith and Neff were found guilty of 2nd degree murder. 6 white men were sentenced up to 3 years in prison. Wright's brother Michael implicated himself in 2003 and was charged for the murder of Schaad. In 2005 York city officials announced a $2 million settlement with the children and sisters of Lillie Belle Allen. (SFC, 4/28/01, p.A5)(SFC, 5/10/01, p.A7)(SFC, 5/17/01, p.A2)(SFC, 5/22/01, p.A5)(YD, 5/24/01)(YD, 6/25/00)(SFC, 10/31/01, p.C2)(SSFC, 10/20/02, p.A7)(SFC, 11/14/02, p.A8)(BS, 6/26/03, 5A)(SFC, 12/7/05, p.A3) 1969 Dec 31, In Clarksville Joseph Yablonski was murdered with his wife and daughter. (SFC, 11/8/99, p.C2) 1969 Philadelphia initiated a program of “career academies," which combined academic and technical curriculums and gave students work experience. (Econ, 6/19/10, p.34) 1969 Leonard Tose (1915-2003) and several others bought the Philadelphia Eagles pro football team for $15.155 million. Tose bought out his partners in 1977. He sold the team in 1985 to Norman Braman of south Florida for $65 (SFC, 4/17/03, p.A23) 1970 Jan 5, Joseph A. Yablonski, an unsuccessful candidate for the presidency of the United Mine Workers, was found murdered with his wife and daughter at their Clarksville, Pa., home. Nine people were later charged in the killing including UMW Pres. W.A. Boyle. (AP, 1/5/98)(SFC, 11/8/99, p.C2) 1970 Jun 21, Penn Central was forced into bankruptcy. The default caught the market by surprise, largely because commercial paper ratings were in their infancy. Fed chairman Arthur Burns reacted by making discount window loans to banks that lent to CP issuers. 1970 Apr 22, The first Earth Day and Earth Week was celebrated and millions protested pollution on Earth and their concern for the environment. The event was organized by a 33-member committee in Philadelphia. Wisconsin Senator Gaylord Nelson suggested Earth Day as a means to focus national attention on ecological issues. Gaylord selected Pete McCloskey as co-chairman. Organizers later identified 12 anti-environment members of the US House and Senate, 7 of whom soon lost their seats. (AP, 4/22/97)(WSJ, 5/12/99, p.A23)(SSFC, 4/18/04, 1970 The Shostakovich (1906-1975) 13th symphony "Babi Yar," smuggled on microfilm to the US, was premiered in the US by the Philadelphia Orchestra. (WSJ, 6/29/99, p.A12)(http://tinyurl.com/69xuxx) 1971 Jan 25, The Philadelphia mint made its 1st trial strike of the Eisenhower dollar. 1971 Jan, Fred Speaker (1930-1996), attorney general of Pennsylvania, ordered the dismantling of the electric chair at the Rockview Correctional Institution on his last day in office. (SFC, 9/17/96, p.A22)(http://tinyurl.com/6qxtu6) 1971 Mar 8, Catholic radicals in Media, Pa., broke into the local FBI offices and stole documents that revealed the agency’s illegal activities against radical groups and leaked them to the media. In 2014 Betty Medsger authored “The Burglary: The Discovery of J. Edgar Hoover’s Secret FBI." Prof. John Raines (1933-2017) and his wife Bonnie were among the eight antiwar activists who took part in the burglary. (SSFC, 1/12/14, p.F1)(SSFC, 11/19/17, p.C9)(SSFC, 1971 Veterans Stadium in Philadelphia opened. Demolition felled it in 2004. (WSJ, 3/25/04, p.D1) 1971 Rev. Leon Sullivan (1922-2001), a noted Philadelphia minister, became GM’s 1st black board member. In 1998 Sullivan authored “Moving Mountains." 1972 Apr 5, The Harrisburg 7 trial ended in mistrial after 11 weeks. Philip Berrigan & Sister Elizabeth McAllister were declared guilty, but only of smuggling letters in & out of prison. Librarian Zoia Horn (d.2014) had refused to testify at the trail, becoming the first US librarian to be jailed for refusing to testify. She was freed after 20 days when a jury deadlocked on conspiracy charges. (www.well.com/~mareev/TIMELINE/1971-1972.html)(SFC, 7/16/14, p.E5) 1972 Sep 18, In Pennsylvania the body of Morgan Peters was found along the Pennsylvania Turnpike. In 2019 Ohio inmate Larry Joseph Via (75) was charged with criminal homicide and robbery in the death of Peters (29), who had been shot in the back, following a grand jury investigation that began in 2017. Police cited writing by Via published in biker magazines. 1972 Nov 8, The Green Channel of Manhattan became Home Box Office (HBO). Time Life gained control of HBO in March, 1973. HBO soon began transmitting programs to cable TV subscribers in Wilkes-Barre, Pa. The 1st cablecast was a National League Hockey game. (WSJ, 1/11/00, p.B1)(SFC, 4/3/01, p.C1) 1972 John J. Rigas incorporated Adelphia Communications in Pennsylvania. The name came from the Greek word for “brother." He took the company public in 1986. 1972-1975 Soul music peaked in Philadelphia. In 2004 John A. Jackson authored “A House on Fire: The Rise and Fall of (SSFC, 11/7/04, p.M3) 1973 Eugene Ormandy (1899-1985) ended his direction of the Philadelphia Orchestra. 1974 Feb 5, John Murtha (1932-2010), became Pennsylvania’s Democratic representative following a special House election. He became the first Vietnam veteran to serve in Congress. 1974 Apr 11, United Mine Workers president W. A. "Tony" Boyle was found guilty of first-degree murder, for ordering the assassination of union reformer Joseph A. "Jock" Yablonski in 1969. Yablonski, his wife and daughter were murdered on December 30, 1969. Boyle had defeated Yablonski in the UMW election earlier in the year-an election marred by intimidation and vote fraud. In 1972 the election was set aside by a federal court after Boyle had been convicted of illegal use of UMW funds in the federal elections of 1968. In a new election held in December, 1972, Boyle was defeated by rank and file reformist Arnold Miller. Soon after the election Boyle was put on trial for murdering the Yablonskis and was sentenced to three consecutive life terms in prison. (HNQ, 11/8/99)(SFC, 11/8/99, p.C2) 1974 Jul 29, The Episcopal Church ordained female priests in Philadelphia. 1974 The Pittsburgh Area Theater Organ Society acquired a Mighty Wurlitzer from the Prospect Theater in Brooklyn for $5,000. (WSJ, 6/29/99, p.A1,4) 1974 The $2.5 million, 393-foot Gettysburg National Tower was erected on private land on the edge of the Gettysburg Civil War battlefield site. It was destroyed in 2000. (SFC, 7/4/00, p.A3) 1974 The firefly was named as the official state insect. (SFEC, 11/21/99, Z1p.2) 1975 Jan 12, The Pittsburgh Steelers beat the Minnesota Vikings (16-6) in the Superbowl in New Orleans. Bob McCurry of Chrysler Corp. introduced the auto rebate in a 1975 Superbowl commercial. 1975 May 6, In hockey the Philadelphia Flyers won the semifinal series over Boston 4 games to 1975 In Pennsylvania a company called McAdoo Associates began operating to extract and recycle metals from chemical wastes. The company accepted hundred of thousands of gallons of paint sludge, waste oils, used solvents, PCBs, cyanide, pesticides and many other known or suspected carcinogens. In 1979, when the EPA stepped in, McAdoo Associates had stockpiled enough chemicals to nearly fill an Olympic-size swimming pool. The EPA placed it on the Superfund list and began a cleanup. The US Agency for Toxic Substances and Disease Registry began looking into polycythemia vera (PCV) in August 2006 after 97 cases in Schuylkill, Carbon and Luzerne counties were reported to the state cancer registry between 2001 and 2005. 1976 Jan 23, Paul Robeson (b.1898), black athlete, lawyer, singer, died in Philadelphia. Lloyd L. Brown later wrote the biography "The Young Paul Robeson: On My Journey Now." His granddaughter Susan Robeson in 1981 wrote "The Whole World in His Hands: A Pictorial Biography of Paul Robeson." (SFC, 3/26/98, p.A26)(WSJ, 4/9/98, 1976 Apr 27, Jimmy Carter clinched the Democratic presidential nomination by beating Henry “Scoop" Jackson and Morris Udall in the Pennsylvania primary. 1976 May 16, The Montreal Canadiens won the Stanley Cup hockey finals in 4 games over the 1976 Jul 4, The nation held a 200th anniversary party across the land in celebration of America's 200 years of independence. President Ford made stops in Valley Forge, Pennsylvania, Independence Hall in Philadelphia, and New York, where more than 200 ships paraded up the Hudson River in (TMC, 1994, p.1976)(IB, 12/7/98)(AP, 7/4/01) 1976 Jul 4, The National Museum of American Jewish History opened in Philadelphia. It was established to tell the story of the American Jewish experience. 1976 Jul 21, "Legionnaire's Disease" struck in Philadelphia, Pa. 29 people died from the disease. The disease was first identified after an outbreak at the Bellevue Stratford Hotel in Philadelphia. It was identified as Legionella pneumophila and found to infest water systems in general and the hotel ventilation system in this case. (OGA, 11/24/98)(SFC, 4/13/96, p.A-17) 1976 Jul 27, Air Force veteran Ray Brennan became the first person to die of so-called "Legionnaire’s Disease" following an American Legion convention in 1976 J. Howard Marshall II (d.1995), Texas oil tycoon and alumnus of Haverford College, Pa., pledged $4 million to Haverford. In 1994 Marshall married Playboy Playmate Anna Nicole Smith (26) and by his death had donated less than $2 million to the college. (WSJ, 7/24/03, p.A1) 1977 Jun 19, Pope Paul VI proclaimed a 19th-century Philadelphia bishop, John Neumann, the first male US saint. 1977 Jul 20, A flash flood hit Johnstown, Pa., killing more than 80 people and causing $350 million worth of damage. 1978 Aug 8, James Ramp (52), Philadelphia police officer, was killed during a standoff with MOVE. 9 members of MOVE, a Black group that espoused equality with animals and preached against technology, were convicted. Members of the group adopted the surname Africa. 1977 Sep, In Philadelphia Helen "Holly" Maddux, a Bryn Mawr College graduate from Tyler, Texas, was murdered and stuffed into a steamer trunk for 18 months until her body was discovered. Ira Einhorn, "hippie guru" was arrested for the murder in 1979 but released on bail. He fled to hide in France. Fred Maddux, Holly's father, committed suicide in 1988. Einhorn was convicted in absentia in 1993. In June,1997, he was arrested in France. A French court ruled against extradition and released Einhorn. Einhorn was arrested in 1998 under a new extradition warrant. The events were broadcast as a TV crime story in 1999 titled "The Hunt for the Unicorn Killer." In 1999 The French Supreme Court ruled that Einhorn should be returned to the US. In 1999 a civil suit ordered Einhorn to pay $907 million to the Maddux family. Einhorn was extradited to the US in 2001. he was convicted of murder Oct 17, 2002. (SFC, 6/17/97, p.A2)(SFC,12/5/97, p.A17)(SFC, 9/22/98, p.A3)(WSJ, 5/3/99, p.A20)(WSJ, 5/12/99, p.A23)(SFC, 5/28/99, p.D3)(SFC, 7/29/99, p.A8)(SFC, 7/20/01, p.A14)(SFC, 1978 Dec 13, The Philadelphia Mint began stamping the Susan B. Anthony dollar, which went into circulation the following July. This was the 1st US coin to honor a (AP, 12/13/97)(MC, 12/13/01) 1979 Jan 21, The Pittsburgh Steelers became the first team to win three Super Bowls as they defeated the Dallas Cowboys 35-31 in Super Bowl 13. 1979 Mar 28, America's worst commercial nuclear accident occurred inside the Unit Two reactor at the Three Mile Island plant near Middletown, Pa., almost to meltdown. Thousands living near the plant left the area before the 12-day crisis ended, during which time some radioactive water and gases were released. A combination of mechanical and human factors allowed the Unit 2 reactor to lose cooling water. It cost more than $1 billion and more than a decade to remove the damaged nuclear fuel. A 1997 study indicated increased cancer rates for people (TMC, 1994, p.1979)(SFC, 6/8/96, p.A2)(SFC, 2/24/96, p.A3)(AP, 3/28/97) (HN, 3/28/98)(MC, 3/28/02) 1979 Nov 1, Mamie Doud Eisenhower (b.1896), wife of former Pres. "Ike" Eisenhower, died at a family farm in Gettysburg, Pennsylvania. 1979 August Wilson, playwright, wrote "Jitney." It was set in the Hill District of Pittsburgh and first performed in 1982. (WSJ, 8/4/99, p.A20) 1979 The song "We Are Family" by Sister Sledge became a hit. It was made the theme song for the 1979 Pittsburgh Pirates. 1980 Oct 2, Michael Myers (D-Pa) became the 1st representative expelled in over 100 years 1980 Ron Perelman acquired MacAndrews & Forbes, a Philadelphia candymaker, for $45 million. Howard Gittis (1934-2007) advised Perelman on the acquisition and in 1985 joined Perelman and his MacAndrews & Forbes Holdings. 1980 Norman, Bruce and David Johnston were sentenced to life in prison for the murder of 4 teenagers to cover up a family burglary ring. (SFC, 8/21/99, p.A3) 1981 Dec 9, In Philadelphia Mumia Abu Jamal shot and killed Officer Daniel Faulkner shortly after the officer stopped William Cook, Jamal’s brother (see July 3, (SFC, 3/28/08, p.A4) 1981 Philadelphia school teachers stage a strike. (SFC, 10/28/00, p.A9) 1982 Jul 3, Mumia Abu-Jamal (b.1954), radio reporter and former Black Panther, was convicted for the 1981 murder of police officer Daniel Faulkner in Pittsburgh. Jamal supporters said he was framed. Prosecutors said Jamal shot Faulkner after seeing the officer struggling with Jamal’s brother, William Cook, who had been stopped for a traffic violation. In 1996 Jamal was still on death row. In 1999 Gov. Tom Ridge signed a 2nd death warrant for lethal injection on Dec 2. In December, 2001, a federal judge affirmed his murder conviction but ordered that Abu-Jamal should either receive a new sentencing hearing or have his sentence commuted to life in prison because of an error by the trial judge in presenting rules of sentencing to the jury (see March 27, 1982 Sep 9, Robert Thibadeau at CMU-10A: Pittsburgh Zoo Options: The zoo is a worthwhile place to visit, but in my three years in Pittsburgh I have watched it deteriorate for lack of funds. Fortunately they have this wonderful 'adopt an animal' program. The adoption can be a day or month. Orangutanns (sic) eat light at $.75 a day or $22.50 a month, and for $15 a day or $450 a month you get yourself an entire elephant. Double that and you can probably have his name changed to Clyde. Triple it and I bet they will let you dye him pink. Visitation rights come with any adoption. The flyer is on my office door -- 1982 Sep 25, Pennsylvania prison guard George Banks killed 13 people including 4 that were his 1982 The Philadelphia Evening and Sunday Bulletin closed. (SFC, 11/24/16, p.D2) 1983 Jan 23, Joseph Coogan (28), an auditor from Pennsylvania, was swept into the sea at Pescadero Point, Ca. His remains washed up at Point Reyes six months later but remained unidentified until 2005. (SFC, 4/14/05, p.A1) 1982 Rich Skrenta (b.1967), a freshman in Pennsylvania, developed Elk Cloner as a practical joke. It was the 1st virus to hit computers worldwide and later became known as a "boot sector" virus. When it boots, or starts up, an infected disk places a copy of the virus in the computer's memory. Whenever someone inserts a clean disk into the machine and types the command "catalog" for a list of files, a copy gets written onto that disk as well. The newly infected disk is passed on to other people, other machines and other locations. (AP, 9/1/07)(SFC, 9/3/07, p.C3) 1983 Oct 23, Jessica Savitch (36), news anchor (NBC-TV), died in an automobile accident with Martin Fischbein in New Hope, Pa. 1983 Nov 8, Wilson Goode was elected as the first black mayor of the city of Philadelphia. 1984 May 26, A frisbee was kept aloft for 1,672 seconds in Philadelphia. 1984 Aug 3, In Pennsylvania Barbara Rowan (14) was raped and killed. Her body was found two weeks after she went missing in Bensalem, Bucks County. In 2015 George Franz Shaw (55) and Robert Scott Sanders were arrested for her rape and murder. 1984 Aug 22, The VW plant at Westmoreland, Pa., produced its last Volkswagen Rabbit. 1984 A 60-by-13-foot tile mural was created by Romare Beardon for a Pittsburgh subway station. In 2008 the mural was valued at $15 million as the station faced (WSJ, 4/25/08, p.A2) 1985 Mar 12, Conductor Eugene Ormandy (85), director of the Philadelphia Philharmonic for more than four decades, died. 1985 May 13, Police in Philadelphia dropped a bomb on the headquarters of the radical group MOVE. A fire resulted that killed 11 people, 5 of them children. Ramona Africa and her 13 year old son were the only two people to escape the inferno at 6221 Osage St. Africa was charged with rioting and conspiracy, was convicted and served 7 years in state prison. No charges have ever been filed against any city officials or employee. The lawsuit was re-opened in 1996. On Jun 24, 1996, a jury in Philadelphia awarded $1.5 mil to the survivors of the MOVE cult. In 2013 the documentary “Let the Fire Burn," directed by Jason Osder, covered the MOVE story with archival footage. (SFC, 4/3/96, p.A-4)(USAT, 6/25/96, p.3A)(AP, 5/13/97)(SFC, 11/1/13, p.E7) 1985 May 31, Some 41 tornadoes swept through parts of Pennsylvania, Ohio, New York and Ontario, Canada, during an eight-hour period killing 88 people with over 1985 Berry Prevor and Steven Shore of Long Island, NY, opened their first Steve and Barry’s store Philadelphia, selling discount Univ. of Pennsylvania apparel. In 2008 the 276-store chain faced Chapter 11 bankruptcy. (WSJ, 7/9/08, p.B1)(WSJ, 7/14/08, p.A1) 1986 Aug 5, It was revealed that Andrew Wyeth secretly created 240 drawings and paintings of his neighbor Helga Testorf, in Chadds Ford, Pa. 1986 A consent decree in Philadelphia limited the number of prisoners who could be held in city jails. Over the next 18 months police rearrested 9,732 defendants. In 2002 Ross Sandler and David Schoenbrod authored "Democracy by Decree," a critique of "institutional reform (WSJ, 12/30/02, p.A1) 1986 The Pittsburgh Supercomputing Center opened. (SFC, 3/9/98, p.A7) 1986 Abhay Ashtekar, a physicist at Pennsylvania State Univ., proposed an explanation called “loop quantum gravity" to relate quantum mechanics with general relativity. This rivaled a popular alternative model called (Econ, 9/30/06, p.89) 1986-1994 Robert P. Casey (d.2000 at 68) served as (SFC, 6/2/00, p.D4) 1987 Jan 22, R. Budd Dwyer, Penn. State Treasurer, facing prison for conspiracy & perjury, shot himself to death at a televised news conference. 1987 Sep 17, The city of Philadelphia, birthplace of the U.S. Constitution, threw a big party to celebrate the 200th anniversary of the historic document. 1987 In the Philadelphia mayor’s race Frank Rizzo lost to black accountant Wilson Goode. Rizzo took 97% of the white vote while Goode won with 98% of the (WSJ, 1/6/98, p.A20) 1987 Pennsylvania officials declared the city of Aliquippa as economically distressed. (WSJ, 5/27/04, p.A1) 1987 Hawks Aloft Worldwide was conceived as a cooperative project by the Hawk Mountain Sanctuary, in Kempton, Pennsylvania. (NH, 10/96, p.41) 1988 Jan 2, An Ashland Oil Company tank collapsed at Floreffe near Elizabeth, Penn., sending more than 700,000 gallons of diesel oil into the Monongahela River. 1988 Jan 4, Drinking water began to dry up in Pittsburgh suburbs because of a massive diesel oil spill two days earlier that fouled the Monongahela and Ohio 1988 William Post III (1940-2006) won a $16.2 million Pennsylvania lottery jackpot. His annual installment payments of $498,000 after taxes led to problems with siblings, his wife and girlfriend, who successfully sued for a third of his earnings. In 1996 a bankruptcy judge auctioned off the remainder of his prize payments to pay off his debts leaving him with $1 million. (SFC, 1/23/06, p.B4) 1989 Apr 12, Abbie Hoffman (52), radical activist, was found dead at his home in New Hope, Penn. He suffered from bipolar mental illness that was only diagnosed in 1980. In 1996 Jonah Raskin wrote: "For the Hell of It: The Life and Times of Abbie Hoffman." In 1994 Jack Hoffman, Abbie’s brother, wrote a biography, as did Marty Jezer in 1992. His wife, Anita, died in 1998. She wrote "Trashing," a fictional memoir of her activity as a Yippie. In 1999 Larry Sloman published "Steal This Dream: Abbie Hoffman and the Countercultural Revolution in America." (SFC, 12/29/96, BR p.5,6)(SFC, 12/31/98, p.D4)(SFEC, 2/14/99, BR p.7) (AP, 4/12/99) 1989 May 11, The Franklin Mills mega-mall, the former Liberty Bell Racetrack, opened in 1989 Jul 29, Ji Yun Lee (20) died in a fire at a church camp near East Stroudsburg, Pa. Her father Han Tak Lee (54), a South Korean-born operator of a clothing store in NYC, was arrested for arson. He was convicted of murder on Sep 17, 1990. In 2006 Lee’s attorneys appealed to the state Supreme Court citing new advances in arson investigations. (SSFC, 12/10/06, p.A39) 1989 Oct, Al Martino, pop singer, was inducted into the Philadelphia Hall of Fame. (SFEC, 10/5/97, DB p.74) 1989 Nov 1, Sadie Tanner Mossell Alexander (b.1898), the first African-American to earn a PhD in economics (1921), died in Philadelphia. She was also the first woman to receive a law degree from the University of Pennsylvania 1989 Nov 18, Pennsylvania became the 1st state to restrict abortions after Supreme Court gave states the right to do so. 1989 Philip Berman (d.1997 at 82), art collector and philanthropist, became chairman of the Philadelphia Museum of Art. He had prospered and retired from the trucking business and led a capital campaign that raised $63.4 million for the museum between 1989 and 1993. (SFC, 12/2/97, p.A22) 1990 Apr 25, Dexter Gordon (67), jazz saxophonist, died in Philadelphia. 1990 Aug 17, Pearl Bailey (b.1918), Broadway actress, singer, died in Philadelphia from a heart attack at age 72. 1990 Nov 11, Stormie Jones, the world’s first heart-liver transplant recipient, died at a Pittsburgh hospital at age 13. 1991 Apr 4, Pennsylvania Senator John Heinz III, a leading 3-term Republican voice on health and trade policy, and six other people, including two children, were killed when a helicopter collided with Heinz’s plane over a schoolyard in Merion, Pennsylvania. Mrs. Teresa Heinz took his place as head of the family philanthropies. In 1995 she married Sen. John (SFC, 9/25/99, p.A21)(AP, 4/4/01)(WSJ, 4/16/04, 1991 Jun 30, The federal base-closing commission voted to shut down 17 military bases, including the massive Philadelphia Navy Shipyard, in addition to seven facilities ordered closed two days earlier. 1991 Jul 16, Frank Rizzo (70), (Mayor-D-Phila, 1972-80), died of a heart attack. 1991 Alex Wolszczan and Dale Frail at Pennsylvania State Univ. reported evidence of 3 extra-solar planets (exoplanets) orbiting around the spinning remains of Pulsar B1257+12. They found the pulsar in 1990 using the Arecibo radio (SSFC, 9/30/01, Par 1992 Oct 27, In Oil City, Pennsylvania, Shauna Howe (11) was kidnapped while walking home from a pre-Halloween party. Her battered body was found 3 days later. For every year afterward, the City Council voted to allow trick-or-treating in the afternoon only. In 2004 a witness came forward and police turned to DNA evidence. Two brothers were arrested and convicted of murder and sexual assault. A third man pleaded guilty to murder. In 2008 the city council voted to allow Halloween back to night hours. 1992 Scranton, Pa., entered Act 47, a state program that provides assistance to financially (Econ, 7/21/12, p.26) 1993 Jan 10, An unidentified 62-year-old man at the University of Pittsburgh Medical Center underwent the world's second baboon liver transplant. The man died less than a month later without regaining full consciousness. 1993 Mar 18, In Pennsylvania Amish man Edward Gingerich outraged his normally peaceful religious community of Rockdale Township, where he crushed his wife's skull and used a kitchen knife to remove her stomach organs from her dead body. Gingerich was diagnosed with schizophrenia and convicted of manslaughter in 1994. After serving his maximum sentence of four years in prison for the killing, moved to a mental institution in Michigan before going to Indiana and eventually returning to Pennsylvania and the Brown Hill Amish community in 2007. In 2011 Gingerich (44) committed suicide in a barn in Cambridge Springs, Pa. 1993 Jul 26, Ret. Gen. Matthew B. Ridgway (98), US Army Chief of Staff (1953-55), died in Fox 1993 Oct 16, The Toronto Blue Jays defeated the Philadelphia Phillies, 8-5, in game one of the 1993 Oct 17, The Philadelphia Phillies defeated the Toronto Blue Jays, 6-4, evening the World Series at one game each. 1993 Oct 19, The Toronto Blue Jays took a 2-1 lead in the World Series by defeating the Philadelphia Phillies 10-3. 1993 Oct 20, Toronto took a 3-1 lead in the World Series as the Blue Jays defeated the Philadelphia 1993 Oct 21, The Philadelphia Phillies beat the Toronto Blue Jays 2-0 in game five of the World Series; Toronto still led the Series 3-2. 1994 Jun 7, Vicki Van Meter 912) of Meadville, Pa., completed a trans-Atlantic flight, landing in Glasgow, Scotland. She was accompanied by her flight instructor. 1994 Sep 8, A US Air Boeing 737 from Chicago crashed near Pittsburgh Int’l. Airport and killed all 132 people onboard. USAir Flight 427 crashed 6 minutes before it was due to land. (SFC, 5/12/96, p.A-14)(AP, 9/8/97)(SFC, 11/13/01, 1994 Nov 1, In Cherry Hill, Pa., Len Jenoff and Paul Daniels clubbed to death Carol Neulander (52), the wife of Rabbi Fred J. Neulander (53), under a contract from Rabbi Neulander. Neulander stood trial in 2001 in New Jersey. He was convicted of murder Nov 20, 2002 and sentenced to life in (SFC, 10/20/01, p.A18)(SFC, 11/21/02, p.A6)(SFC, 1994 Nov 11, Eddie Polec (16), a Fox Chase high school student, died after being clubbed to death by students of Abington High School. On March 20, 1996, Carlo Johnson (20) and Bou Khathavong (18) – believed by prosecutors to be the ring leaders in the assault, although neither beat Polec – received maximum five- to 10-year sentences for conspiracy. Prosecutors believe the two organized the rumble and provided the baseball bats. Anthony Rienzi and Nick Pinero, both 18, were sentenced to the maximum 15- to 30-year terms for third-degree murder and conspiracy. Thomas Crook (19) sobbed and apologized to his family before receiving 14.5 years to 30 years on the same charges. Dawan Alexander (18) who was convicted of manslaughter for kicking Polec, received an eight- to 20-year term. Seventh defendant Kevin Convey (19) had pleaded guilty earlier to third-degree murder in exchange for testifying against the others. In February he had been sentenced to five to 20 years. In 2000 Bryn Freedman and William Knoedelseder authored "In Eddie’s Name: One Family’s Triumph (SFEC, 5/14/00, BR 1994 The Andy Warhol Museum opened in Pittsburgh. (SFEC, 8/13/00, p.T11) 1994 Steven Spielberg helped establish the Righteous Persons Foundation. In 2008 $1 million from the foundation was given toward establishing a new Museum of American Jewish History in Philadelphia. (SFC, 7/4/08, p.E15) 1994 Judith Rodin (b.1944) began serving as president of the Univ. of Pennsylvania. She served until 2004 and in 2005 became president of the Rockefeller 1995 Aug 7, Ten days before he was to be put to death for the murder of a police officer, black activist and radio reporter Mumia Abu-Jamal won a reprieve from the original trial judge in Philadelphia. As of 2008, his legal appeals are still unsettled and he is a prisoner at State Correctional Institution Greene near Waynesburg, Pennsylvania. 1995 Oct, Jonny Gammage died from asphyxiation when police officers subdued him following a traffic stop in Overbrook. In 1999 the Justice Dept. closed its case against the officers due to lack of evidence that they used (SFC, 2/19/99, p.A5) 1995 Dec 24, Fire broke out at the Philadelphia Zoo, killing 23 rare gorillas, orangutans, gibbons 1995 Erie’s congressman Tom Ridge became governor. (WSJ, 7/13/00, p.A28) 1995 Abu-Jamal, in jail for a 1981 murder conviction, published "Live from Death Row." (SFC, 1/22/99, p.A2) 1996 Jan 14, The Pittsburgh Steelers defeated the Indianapolis Colts, 20-to-16, to win the AFC championship. The Dallas Cowboys beat the Green Bay Packers, 38-to-27, to win the NFC championship. 1996 Jan 26, Olympic wrestler Dave Schultz was fatally shot at the suburban Philadelphia estate of John E. du Pont; du Pont surrendered 48 hours later. Du Pont was later convicted of third-degree murder but mentally ill; he's serving a 13- to 30-year sentence. 1996 Jun 27, Anne Marie Fahey (30), the secretary of Delaware Gov. Thomas Carper, disappeared from Wilmington after dining at a Philadelphia restaurant with Thomas Capano. Capano, a prominent lawyer who had dated Fahey, was later accused of her murder based on testimony from his two brothers. In 1998 Capano admitted that he disposed Fahey’s body but insisted that her death was an accident. In 1998 Capano testified that Fahey was shot accidentally by former mistress Deborah MacIntyre, who denied the charge. Capano was convicted by a jury on Jan 17, 1999. On Mar 16, 1999, Capano was sentenced to death. (SFEC,12/14/97, p.A4)(SFEC, 10/5/98, p.A5)(SFC, 10/27/98, p.A2)(SFC, 12/22/98, p.A2)(SFC, 1/18/99, p.A2)(SFC, 1996 Nov 13, An all-white jury in Pittsburgh acquitted a suburban police officer, John Vojtas, in the death of black motorist Jonny Gammage in a verdict that angered 1996 Binney & Smith Inc. established the Crayola Factory Museum in Easton, Pa. (WSJ, 4/30/98, p.A1) 1996 Peter Wright (1917-2007), founder of started Wright’s Keystone Helicopter Corp. (1953), served as the founding chairman of the American Helicopter Museum in West (WSJ, 6/16/07, p.A6) 1996 David Nam broke into the Philadelphia house of Anthony Schroeder (75) to rob him and killed the retired police officer when he resisted with his own gun. Nam was arrested in 1997 but fled to South Korea in 1998 while under house arrest. In 2008 Nam was arrested by police in South Korea. 1997 Feb 23, In Philadelphia a group of white men attacked a black family in the Grays Ferry section. Nine men were tried in 1998 and 6 were convicted on a variety of felony accounts. (SFC, 2/10/98, p.A3) 1997 Feb 25, A jury in Media, Pa., convicted multimillionaire John E. du Pont of third-degree murder, deciding he was mentally ill when he killed world-class wrestler David Schultz. Du Pont was sentenced to serve 13- to 30-years in prison. 1997 Mar 26, Former drug counselor John G. Bennett Jr. pleaded no contest in Philadelphia to charges stemming from a $100 million charity fraud. Bennett was sentenced to 12 years in prison for fraud, tax violations and money 1997 Aug 12, Steel workers in West Virginia, Ohio and Pennsylvania ended a 10-month strike at Wheeling-Pittsburgh Steel Corp. with a new contract. It was the longest strike by a major steel company. (SFC, 8/13/97, p.A3) 1997 Sep, Devon Capital Management under John Gardner Black was shut down by the SEC. Mr. Black was charged with fraud after losing millions in high-risk bonds and derivatives and then trying to cover up the losses. Some $70 million was lost from the investments of 64 cash-strapped school districts in the state. (WSJ, 12/26/97, p.A1) 1997 Oct 24, A firebomb killed a grandmother, her daughter and three children in a blighted neighborhood of crack houses. 1997 Oct 25, The Million Woman March was in Philadelphia to revitalize black families and communities drew an estimated 300,000 to one million people. (SFC, 10/10/97, p.A3)(SFEC,10/26/97, p.A1)(AP, 1997 Nov 26, It was reported that Philadelphia agreed with the Norwegian shipbuilder Kvaerner ASA to a 99-year lease on 114 acres of the former Naval Shipyard that includes 2 drydocks with the option to buy the property for 1 dollar at the end of the lease. (WSJ, 11/26/97, p.B8) 1997 Dec 21, Johnny Coles (71), jazz trumpeter, died in Philadelphia. His records included "The Warm Sound of Johnny Coles" and "Little Johnny C." 1997 The Zippo Manufacturing Co. opened a Zippo museum in Bradford to celebrate its 65th (Hem., 10/97, p.78) 1997 John Street, Philadelphia City Council president and later mayor, proposed a rigid anti-loitering law aimed at clearing city streets of panhandlers. An estimated 4,500 homeless lived in Philadelphia at the time. A campaign to move the homeless into shelters reduced the number on the streets to 130 in 2004. (SSFC, 6/13/04, A22) 1997 In Pennsylvania Ghassan Saleh escaped from a federal prison near Bradford while working on a grounds crew. He had been serving a sentence of almost six years after being convicted of cocaine trafficking in Michigan. In November, 2017, Saleh (66) was arrested after flying into New York City from Lebanon, his native country. 1998 Jan 7, The book "A Prayer for the City" by Buzz Bissinger was about Philadelphia mayor Ed Rendell and his last 3 years in office. Rendell served 2 terms from (WSJ, 1/6/98, p.16)(SFC, 1/4/00, p.A7) 1998 Mar 22, In Miles Township, Pa., 11 students were killed in a cabin fire while on a camping (SFC, 3/23/98, p.A2) 1998 Apr 13, An Amtrak train collided with Conrail freight cars near Pittsburgh and injured 20 (WSJ, 4/14/98, p.A1) 1998 Apr 24, In Pennsylvania a 14-year-old boy was arrested after he shot a teacher to death and injured 2 others during a dance for 8th graders in Edinboro. Andrew Wurst (14) later pleaded guilty to third-degree murder and was sentenced to 30 to 60 years in prison. (SFC, 4/25/98, p.A3)(AP, 4/24/03) 1998 May 10, In Clearfield, Pa., Kimberly Jo Dotts (15) was hanged to death by teenagers who planned to run away to Florida. Seven young people 14-24 were arrested for murder and the trial of Jessica Holtmeyer (16) and Aaron Straw (19) began in 1999. Holtmeyer was convicted Jan 28. (SFC, 1/18/99, p.A8)(SFC, 1/29/99, p.A6) 1998 Jun 1, In Philadelphia the largest transit union went on strike and shut down a system that served 435,000 people a day. This followed 3 months of negotiations with the transportation authority (SEPTA). (SFC, 6/2/98, p.A5) 1998 Jun 10, Dr. Stephen Grosse, a flamboyant gay dentist, was found shot dead in his burning car near Philadelphia. (SFC, 6/20/98, p.A3) 1998 Jun 15, Police and federal agents and garbage trucks began Operation Sunrise in Philadelphia to clean up a blighted neighborhood. (SFC, 6/16/98, p.A3) 1998 Jun 20, Seven people were killed on the Pennsylvania Turnpike when a Greyhound bus crashed into a tractor-trailer parked on the shoulder. At least 18 people were hurt. The driver was on his last run before retirement. he was among the dead with his wife and boy that they took care of. (SFEC, 6/21/98, p.A10)(WSJ, 6/22/98, p.A1) 1998 Jun 23, Laboratory grown adult nerve cells were implanted into a human brain for the first time to treat a stroke at the Univ. of Pittsburgh Medical Center. (SFC, 7/2/98, p.A2) 1998 Jun, Federal prosecutors accused 2 Amish men of buying cocaine from a local chapter of the Pagan Motorcycle Club and distributing it to their friends at "running around" parties (rumschpringes in Dutch). (SFC, 7/2/98, p.A7) 1998 Jul 11, Public transit resumed and the 40-day transit strike came to a tentative end after a contract agreement was reached. (SFEC, 7/12/98, p.A8) 1998 Aug 5, Marie Noe of Philadelphia (69), was arrested and charged with murdering 8 of 10 children by suffocation over a 19 year period (1949-1968). In 1999 Noe (70) pleaded guilty and was sentenced to 20 years probation. (SFC, 8/6/93, p.A3)(SFC, 6/29/99, p.A2)(AP, 1998 Sep 17, In Apollo, Pennsylvania, nuclear-processing plant operators were ordered to pay 8 cancer-stricken victims $36.5 million. (WSJ, 9/18/98, p.A1) 1998 Sep, The brown marmorated stink bug (Halyomorpha halys), an insect not previously seen in North America, was first collected in Allentown, Pa. It had probably arrived several years earlier. It is known as an agricultural pest in its native range of China, Japan, Korea and Taiwan. (Econ, 9/10/11, p.36)(http://tinyurl.com/nkexo3) 1998 Dec 17, In Gabon Karen Phillips (37), a US Peace Corps worker from Philadelphia, was raped and stabbed to death in Oyem. 3 people were arrested in connection with her death. (SFEC, 12/20/98, p.C10) 1999 Feb 19, In Allentown, Pa., An explosion at a chemical processing plant in the Lehigh Valley Industrial Park killed 5 people and injured 14. (SFEC, 2/21/99, p.A7)(WSJ, 2/22/99, p.A1) 1999 Jun 18, In Norristown Dennis Czaikowski (40) shot and killed Carol Kepner (54) and wounded Maria Jordan (37) before being subdued by police following a standoff at the Norristown State Hosp. where he had been fired. (SFC, 6/19/99, p.A4) 1999 Aug 7, In China Song Yongyi, a research librarian at Dickinson College in Carlisle, Pa., was imprisoned while collecting data on the Cultural Revolution. On Dec 12 he was charged with "the purchase and illegal provision of intelligence to foreigners." Yongyi was released on Jan 28, 2000. (SFC, 1/26/00, p.A8)(SFC, 1/29/00, p.A8) 1999 Aug 16, Gov. Tom Ridge ordered a lockdown of all state prisons following the escape Michael McCloskey (43) and Anthony Yang (31) from the State Correctional Institution at Dallas. (SFC, 8/17/99, p.A3) 1999 Sep 7-19, Hurricane Floyd caused one death in Caribbean and 56 in United States. Storm hit Bahamas before striking Florida, North Carolina, Pennsylvania, New Jersey, Virginia, Delaware, New York, Connecticut, and Vermont. 1999 Oct, The plum pox virus made its first appearance in North America in Pennsylvania orchards. (SFC, 11/27/99, p.A20) 1999 Nov 2, Democrat John F. Street became the 2nd black mayor of Philadelphia with his win over (SFC, 11/3/99, p.A17) 1999 Nov 21, A Penn State student and a bus driver were killed when 4 charter buses crashed on I-80 in heavy fog. (SFC, 11/22/99, p.A9) 1999 Dec 5, W. Russell G. Byers (59), a Daily News columnist, was stabbed to death as he fought off a robber by a convenience store in the Chestnut Hill section of (SFC, 12/6/99, p.B2) 2000 Feb 3, Nancy Hershey Bromer, publisher of "Old News," died at age 78. Old News had begun as a monthly magazine about Pennsylvania history in the 1980s and later expanded to national and world history. (ON, 3/00, p.3) 2000 Feb 5, An oil pipeline began leaking and released some 25,000 gallons below the surface of a frozen pond in the John Heinz National Wildlife Refuge in (SFC, 2/7/00, p.A10) 2000 Mar 1, In Pennsylvania Ronald Taylor (39) killed 3 people and wounded 2 at an apartment and 2 fast food restaurants in Wilkinsburg. In 2001 Taylor was sentenced to death for the killing of 3 white men. (SFC, 3/2/00, p.A3)(AP, 3/1/01)(SFC, 11/12/01, 2000 Mar 19, At Bloomsburg Univ. a fire at the off-campus Tau Kappa Epsilon fraternity killed 3 (SFC, 3/20/00, p.A10) 2000 Apr 21, In Sinking Spring Carlos Angel Diaz Santiago (22) pushed the car of his former girlfriend onto the tracks of an oncoming train. Candace Wertz (20), her son (2), Cynthia Jacques (22), and her daughter (2) were killed. (SFC, 4/22/00, p.A3) 2000 Apr 28, In Pennsylvania Richard Baumhammers (34) shot and killed 5 people in a racially motivated shooting spree in McKees Rocks. He was sentenced to death (SFC, 4/29/00, p.A3)(BS, 5/12/01, p.3A) 2000 May 18, In Philadelphia a 91-year-old pier at a new open-air bar collapsed into the Delaware River and 3 people were killed. (SFC, 5/19/00, p.A3)(WSJ, 10/10/01, p.B1) 2000 May 21, In Pennsylvania a commuter plane, returning from Atlantic City, NJ, crashed near Wilkes-Barre and all 19 people aboard were killed. (SFC, 5/22/00, p.A1) 2000 Jun 26, The new United Religions organization planned a charter signing ceremony at Carnegie Mellon Univ. in Pittsburgh. Episcopal Bishop William Swing first announced his dream June, 1995, at Grace Cathedral in SF. A 41-member Global Council will coordinate activities. 24 members will be chosen by a worldwide membership in 8 regional elections, with a dozen at-large trustees and 5 seats from the current board. The basic unit of the organization will be a group of 7 or more people from a mix of religious traditions. (SFC, 6/19/00, p.A1,5) 2000 Jun 18, A US F-14 Tomcat fighter jet crashed during an air show at Willow Grove, Pa. Two naval aviators were killed. (SFC, 6/20/00, p.A9) 2000 Jul 3, The $2.5 million, 393-foot Gettysburg National Tower, erected in 1974, was destroyed. (SFC, 7/4/00, p.A3) 2000 Jul 12, In Philadelphia a WPVI News camera showed city police beat and kick Thomas Jones (30) over nationwide TV. Jones had stolen a patrol car and shot at an officer. Jones later pleaded guilty to carjacking and other crimes, and was sentenced to 18 to 36 years in prison. Ballistic tests later showed that Officer Michael Livewell was shot in the thumb by another officer during their struggle with Jones. 13 police officers were later suspended for up to 15 days in connection with the (SFC, 7/14/00, p.A1,16)(SFC, 8/8/00, p.A5)(AP, 2000 Jul 31, The Republican National Convention opened in Philadelphia. (SFEC, 7/30/00, p.A1) 2000 Aug 1, In Philadelphia police arrested at least 280 protesters and raided a warehouse site used as a staging area for passive resistance demonstrations. 15 police officers were injured. (SFC, 8/2/00, p.A9)(SFC, 8/5/00, p.A3) 2000 Sep, In Pennsylvania Jamal Kelly was killed. Donald Outlaw spent 15 years in prison for Kelly's murder when he found out the man he was convicted of killing had told police with his dying breath that someone else named “Shank" had shot him. At Outlaw’s trial in 2004 the victim’s dying declaration that “Shank" did it was never disclosed. On Dec. 29, 2020, Outlaw was officially exonerated. In 2021 he filed a federal lawsuit against the city of Philadelphia and the two detectives who investigated the killing. 2000 Oct 1, Pope John Paul II on China’s national day, canonized as martyrs 87 Chinese believers and 33 European missionaries killed between 1648 and 1930. He also canonized Mother Katherine Drexel (d.1955), a Philadelphia heiress, who became a nun. (SFC, 10/2/00, p.A12)(Econ, 12/18/10, p.78) 2000 Oct 27, Philadelphia teachers called a strike. Mayor John Street planned a talk with Gov. Tom Ridge on arranging a "friendly takeover" of the school system by the state to force teachers back to work. (SFC, 10/28/00, p.A9) 2000 Dec 28, Masked men shot and killed 7 people in a suspected drug house in Philadelphia. (SFC, 12/29/00, p.A3) 2001 Mar 7, In Williamsport a 14-year-old girl at Bishop Neumann High School shot and wounded a 13-year-old classmate with a .22 caliber handgun. (SFC, 3/8/01, p.A5) 2001 Apr 13, In Philadelphia a fire at a boarding house killed 7 people. The unlicensed house was home to seniors and disabled people. (SFC, 4/14/01, p.A5) 2001 Apr 28, It was reported that researchers at the Univ. of Pennsylvania had used gene therapy to reverse a form of congenital blindness in dogs. (SFC, 4/28/01, p.A3) 2001 Apr, Willie Stargell (61), former Pittsburgh Pirates baseball Hall of Fame star (1962-1982), died in North Carolina of a stroke. (WSJ, 4/10/01, p.A1) 2001 May 13, Jason Miller (62), actor-playwright, died in Scranton, Pa. 2001 Jun 17, Tropical Strom Allison moved into southeastern Pennsylvania and killed 4 people. This raised the toll from Allison to at least 43. (SFC, 6/18/01, p.A7) 2001 Sep 11, 10:10 a.m. United Airlines Flight 93, a Boeing 757 carrying 45 people, crashed southeast of Pittsburgh. The plane had left Newark for SF but was believed to be directed by hijackers to Camp David. Passengers appeared to have overcome the hijackers. In 2002 it was reported that Congress was the target. (SFC, 9/12/01, p.A6,10,12)(WSJ, 9/12/01, p.A1)(SFC, 11/6/01, p.A6)(WSJ, 9/12/01, p.A1,3) (WSJ, 2/24/05, p.A1) 2001 Sep 13, The data flight recorder for United Flight 93 was found at the Pennsylvania crash site. 18 hijackers were identified as ticketed passengers in the Sep 11 terrorist attack. (WSJ, 9/14/01, p.A1) 2001 Sep 20, Pres. Bush named Gov. Tom Ridge (56) of Pennsylvania to direct the new office of (SFC, 9/21/01, p.A16) 2001 Oct 19, In Philadelphia luggage, from a baggage locker that was deposited Sep 29, was found to contain C-4 plastic explosives. (SFC, 10/20/01, p.A17) 2001 Dec 9, An Amtrak Acela train killed 3 people on tracks northeast of Philadelphia. (WSJ, 12/10/01, p.A1) 2001 Dec 10, In Philadelphia a gunman opened fire outside the Great Valley Shopping Center in East Whiteland Township and killed 2 people. A 3rd was wounded. (SFC, 12/11/01, p.A9) 2001 Dec 18, A federal judge in Philadelphia threw out Mumia Abu-Jamal's death sentence for the 1981 shooting of a Philadelphia police officer and ordered a new sentencing hearing for the former Black Panther alternately portrayed as a vicious cop-killer and a victim of a racist frame-up. Both sides appealed the ruling. (SFC, 12/19/01, p.A1)(AP, 12/17/02) 2001 Dec 21, Gov. Mark Schweiker announced an agreement on a state takeover of the Philadelphia school system. Plans called Edison Schools Inc. to help run the district. (SFC, 12/22/01, p.A4) 2001 Dec 28, In Pennsylvania a 30-50 car crash on snow-slickened I-80 left 5 people dead near Williamsport. Another 50 cars were involved in 2 pileups that left at least 2 people dead. (SFC, 12/29/01, p.A6) 2001 Dec, The $265 million Kimmel Center for the Performing Arts approached completion. The Philadelphia structure was designed by Rafael Viñoly. (WSJ, 12/20/01, p.A13) 2001 Verizon Hall, home of the Philadelphia Orchestra, opened at the Kimmel Center in Philadelphia, (WSJ, 5/18/06, p.D8) 2002 Jan 7, Louis Pollak, a federal judge in Philadelphia, challenged the scientific validity of fingerprint evidence. In March Pollak declared fingerprint id to be the "bedrock of forensic science." (SSFC, 2/24/02, p.A1)(SFC, 3/14/02, p.A3) 2002 Jan 25, In Pittsburgh 2 masked gunmen killed 2 men and a young girl in a sandwich shop. (SSFC, 1/27/02, p.A17) 2002 Feb 4, A New Jersey teenager (16) began a 2-day shooting spree on the outskirts of Philadelphia that left 6 people dead. He was arrested Feb 22. (SSFC, 2/24/02, p.A1) 2002 Apr 18, Researchers in Pittsburgh reported a strain of Group A streptococci resistant to erythromycin (the macrolide class of antibiotics). (SFC, 4/18/02, p.A4)(WSJ, 4/18/02, p.A1) 2002 Jul 23, Chaim Potok (73), rabbi and author of novels that included "The Chosen," died at his home in suburban Philadelphia. "Literature presents you with alternative mappings of the human experience." (SFC, 7/24/02, p.A1) 2002 Jul 24, John Rigas (78), CEO of Adelphia Comm. Corp., was arrested with his 2 sons on charges of that they looted the company of more than $1 billion. (SFC, 7/25/02, p.A1) 2002 Jul 24, In Pennsylvania 9 coal miners were trapped by a flood 240 feet underground. All 9 were rescued Jul 27. (WSJ, 7/26/02, p.A1)(SSFC, 7/28/02, p.A1) 2002 Jul 25, Encouraged by a tinny tapping sound coming up from the depths, rescuers in Somerset, Pa., brought in a huge drill in a race to save nine coal miners trapped 240 feet underground by a flooded shaft. 2002 Jul 26, Hershey Foods in Hershey, Pa., announced that it would put itself up for sale under directions by the Hershey Trust Co. (SFC, 7/26/02, p.B3) 2002 Jul 28, In Somerset, Pennsylvania 9 coal miners, trapped July 24 by a flood 240 feet underground, were rescued after 77 hours underground in the Quecreek (SSFC, 7/28/02, p.A1)(AP, 7/28/03) 2002 Aug 7, Destiny Wright disappeared at a sleepover with other children in Philadelphia. Abdul El-Shabazz (18) was arrested the next day and led police to (SFC, 8/10/02, p.A5) 2002 Aug 10, Leaders of Roman Catholic religious orders, meeting in Philadelphia, approved details of their plan to keep sexually abusive clergy away from children, while retaining them in the priesthood, creating review boards to monitor how their communities handle offenders. 2002 Oct 1, Walter H. Annenberg (94), media tycoon, philanthropist and former ambassador, died in Wynnewood, Pa. Biographies included "Legacy: A Biography of Moses and Walter Annenberg" by Christopher Ogden and "The Annenbergs" by (SFC, 10/2/02, p.A2) 2002 Oct 15, A listeria outbreak blamed for at east 7 deaths in the northeast was traced to a Wampler Foods plant in Franconia, Pa. (SFC, 10/16/02, p.A5) 2002 Oct 17, Ira Einhorn, the '70s hippie guru who had fled to Europe after being charged with murder, was convicted in Philadelphia of killing his girlfriend, Holly Maddux, and stuffing her corpse in his closet a quarter-century earlier. He was later sentenced to life without 2002 Nov 10, A series of pulverizing storms barreled through more than a half-dozen US states including Tennessee, Ohio, Alabama, Mississippi and Pennsylvania, killing at least 36 people. More than 100 were injured. (SFC, 11/12/02, p.A4)(AP, 11/10/07) 2002 Semion Mogilevich (b.1946), a Ukrainian businessman, and Igor Fisherman were indicted in Philadelphia on charges of money laundering and securities fraud in connection with the collapse of YBM Magnex, Inc. in which investors lost some $150 million. In 2006 Mogilevich was under investigation for possible links to natural gas deals between Russia (WSJ, 12/22/06, p.A11) 2002 The US Geological Survey estimated there may be 1.9 trillion cubic feet of gas in the Marcellus Shale of Pennsylvania. In 2008 Prof. Terry Engelder of Pennsylvania State Univ. estimated the amount at 168 trillion cubic feet. US consumption in 2007 was 23.05 trillion. The Marcellus shale formation stretched some 600 miles along the Appalachians from New York to West Virginia. (WSJ, 4/2/08, p.A2)(Econ, 3/16/13, SR p.6) 2003 Mar, Philadelphia school officials began an inventory of stored art. By 2004 some 1,200 works were counted with an estimated value in the millions. (SFC, 7/8/04, p.A2) 2003 Apr 19, In northeast Pennsylvania Hadley Bilger (13) was abducted by her uncle after he shot and killed her parents. Bilger was released the next day and Robert Lee Hixson (42) surrendered to police. (AP, 4/20/03)(SFC, 4/21/03, p.A3) 2003 Apr 24, In Red Lion, Pa. James Shetts (14), a student armed with at least two handguns, fatally shot Eugene Segro (51), his school principal, in a crowded cafeteria before killing himself. (Reuters, 4/24/03)(SFC, 4/25/03, A7) 2003 Jun 17, John Redwood (60), actor and playwright, died in south Philadelphia. His plays included "No Niggers, No Jews, No Dogs" (2001). (SFC, 7/1/03, p.A17) 2003 Aug 28, In Erie, Pa., Brian Douglas Wells (46), pizza delivery man, was killed when a bomb strapped to his chest exploded while under police custody. Wells claimed a customer had strapped on the bomb and ordered him to rob a bank. In 2007 a grand jury indicted 2 people in connection with the crime. Marjorie Diehl-Armstrong (59), described as the ringleader, pleaded guilty but mentally ill for killing her boyfriend to keep him silent about the robbery. Diehl-Armstrong was trying to raise money to hire Kenneth Barnes to kill her father due to an inheritance dispute. In 2008 Kenneth Barnes (54) pleaded guilty to conspiracy. In 2010 Diehl-Armstrong was convicted for her role in the robbery. In 2011 she was sentenced to life plus 30 years in (SSFC, 8/31/03, p.A8)(AP, 7/11/07)(SFC, 9/4/08, p.A7)(SFC, 11/2/10, p.A5)(SFC, 3/1/11, p.A4) 2003 Nov 14, In Pittsburgh, Pa., a 3rd person died from an outbreak of hepatitis A that infected nearly 600 people. They all had recently eaten at a Chi-Chi's Mexican mall restaurant. Green onions were blamed for the outbreak. (SFC, 11/15/03, p.A3)(AP, 11/16/03)(SFC, 2003 Dec 4, Federal prosecutor Jonathan Luna was attacked after leaving his office in Baltimore around midnight. His body was found 6 hours later, stabbed 36 times apparently in a furious fight for his life before drowning in a Pennsylvania creek. Luna was involved in the prosecution of rapper Deon Lionel Smith (32) and Walter Oriley Poindexter. (AP, 12/5/03)(SFC, 12/5/03, p.A6) 2003 Dec 15, Charles Cullen (43), a former nurse, was charged with murder after telling prosecutors that he killed 30-40 severely ill patients in Pennsylvania and New Jersey since 1987 by injecting them with drugs. Cullen later pleaded guilty to killing 29 people and attempting to kill six others; he was sentenced to 18 life prison terms. (SFC, 12/17/03, p.A3)(WSJ, 4/30/04, p.A1)(SFC, 5/20/04, p.A3)(AP, 12/15/08) 2003 Dec 29, Paul Goldman, a native of Uzbekistan, stabbed and killed Faina Zonis in the Philadelphia suburb of Bensalem. Goldman soon fled the country. Police found his parents dead by suicide on Jan 13. Goldman was captured in France on Jan 20, 2004. Zonis committed suicide Apr 11, (SFC, 1/17/04, p.A4)(SFC, 1/21/04, p.A3)(AP, 2003 Pittsburgh joined 14 other Pennsylvania cities classified as economically distressed. (WSJ, 5/27/04, p.A1) 2004 Jan 19, The Pennsylvania Turnpike Commission voted to raise tolls an average of 42% for all (USAT, 1/20/04, p.12A) 2004 Mar 21, Veterans Stadium (b.1971) in Philadelphia was demolished in 62 seconds following (WSJ, 3/25/04, p.D1) 2004 Mar 27, Edward J. Piszek (87), founder of Mrs. Paul's Kitchens, died in Fort Washington, Pa. (SFC, 4/1/04, p.B7) 2004 Jul 5, Gov. Ed Rendell signed laws authorizing 61,000 slot machines in Pennsylvania, more than any other state except Nevada. Most of the state's share will pay for a $1 billion cut in property taxes a year. 2004 Jul 8, John Rigas (79), founder of Adelphia Communications Corp. (1952), was convicted along with his son Timothy of looting the cable company to line their own (SFC, 7/9/04, p.C1)(USAT, 7/9/04, p.1B) 2004 Jul 12, A foot or more of rain fell in parts of the Northeast. No injuries had been reported in the stricken areas of New Jersey, Pennsylvania and Maryland. 2004 Jul 16, PNC Financial, based in Pennsylvania, agreed to by Riggs National of Washington DC for $779 million. Riggs was fined $25 million in May for violating money laundering regulations. (Econ, 7/24/04, p.69) 2004 Sep 1, It was reported that for about $10 million, Philadelphia city officials planned to turn all 135 square miles of the city into the world's largest wireless Internet hot spot. EarthLink was given the contract and planned to rent 4,000 city light posts for its equipment. Completion of the network was expected in Spring 2007. (AP, 9/1/04)(SFC, 3/2/06, p.C2) 2004 Oct 18, The Dover, Pa., school district voted 6-3 to mandate the teaching of “intelligent design" in public schools along with the theory of evolution. A number of parents soon filed suit. In 2007 Edward Humes authored “Monkey Girl: Evolution, Education, Religion, and the Battle for (SFC, 11/30/04, p.A1)(SFC, 12/15/04, p.A4)(WSJ, 2004 Nov 19, Police in Abington, Pennsylvania, arrested Michael Cornelius Burke Jr. (38) for the assault and rape of 2 girls ages 10 & 13. In Apr 2006 Burke pleaded guilty but failed to show up for sentencing. In 2009 Burke was arrested in Mexico’s in central Veracruz state. 2004 Dec 13, A Montgomery County, Pa., judge allowed trustees of the Barnes Foundation to move the Barnes art collection to downtown Philadelphia from Lower Meriod (SFC, 12/15/04, p.E5) 2005 Jan 23, The Philadelphia Eagles defeated the Atlanta Falcons 27-10 to win the NFC championship game; the New England Patriots won the AFC championship by beating the Pittsburgh Steelers, 41-27. 2005 Feb 25, Hall of Fame basketball coach John Chaney was suspended for the rest of the regular season by Philadelphia’s Temple Univ. for ordering rough play by one of his players during a game against Saint Joseph's. 2005 Mar 26, A small plane, carrying 2 Rhode Island families from vacation in Florida, crashed near Penn. State Univ. All 6 people aboard were killed. (SSFC, 3/27/05, p.A3) 2005 Jun 7, Terry Long, former Pittsburgh Steelers lineman, died in a hospital about five hours after he was found unresponsive in his suburban Pittsburgh home. An Oct 19 revised death certificate indicated that he had committed suicide by drinking antifreeze, and did not die as a direct result of football-related head injuries. 2005 Jun 12, I fire in Philadelphia left 5 children dead. Security bars on windows may have hampered escape attempts. (SFC, 6/13/05, p.A3) 2005 Jul, Pennsylvania legislators increase their salaries 16 percent to 34 percent to at least $81,050, more than any state except California, and crafted the package in secret without debate or public scrutiny. They also found a way around a constitutional provision barring them from collecting any salary increase during the term in which it is approved. Democratic Gov. Ed Rendell signed the bill into law. A lawsuit was soon filed in state court challenging the legality of paying the raises early as unvouchered expenses, though no hearing date has been set. A ruling against the unvouchered expenses would nullify the entire law, including their raises. 2005 Jul 18, LaToyia Figueroa, who was five months' pregnant, was last seen in West Philadelphia. Police recovered her remains a month later. On August 20, 2005, They arrested Steven Poaches, her former boyfriend and the father of the unborn child. On October 17, 2006, in a nonjury trial, Common Pleas Judge M. Teresa Sarmina found Stephen Poaches, guilty of two counts of first-degree murder in the deaths of 24-year-old LaToyia Figueroa and her fetus. Poaches waived his right to appeal and, in exchange, prosecutors agreed not to seek the death penalty. He was given an automatic life sentence with no parole. 2005 Sep 24, Monica Lozada-Rivadineira (26), an immigrant from Bolivia, disappeared in NYC. Her daughter, Valery, was found in the evening wandering barefoot in Queens. On Oct 6 Police found her body in a Pennsylvania landfill and police said she was killed by her boyfriend. In 2006 Cesar Ascarruna (32) pleaded guilty to manslaughter and reckless endangerment. He was sentenced to 32 years in prison. (AP, 10/7/05)(SFC, 3/16/06, p.A3) 2005 Oct 7, John Rigas and his son, founders of bankrupt Adelphia Communications, were indicted for failure to pay some $300 million in taxes. (SFC, 10/8/05, p.C1) 2005 Oct 31, A transit strike in Philadelphia brought the city’s buses, subways and trolleys to a (SFC, 11/1/05, p.A3) 2005 Nov 8, Pennsylvania voters came down hard on school board members who backed a statement on intelligent design being read in biology class, ousting eight Republicans and replacing them with Democrats who want the concept stripped from the science curriculum. 2005 Nov 13, In Lititz, Pennsylvania, David G. Ludwig (18) killed 14-year-old Kara Beth Borden's parents, Michael F. and Cathryn Lee Borden, after they and their daughter argued about her curfew. David and Kara were arrested Nov 14 in Indiana following a police chase and crash. On June 14, 2006, Ludwig agreed to a plea deal and was sentenced to two terms of life imprisonment without chance of parole. (AP, 11/14/05)(SFC, 11/15/05, 2005 Nov 15, Harold Wilson of Philadelphia was acquitted, based on DNA evidence, of a triple homicide after serving sixteen years in prison. (Econ, 12/19/15, p.33) 2005 Nov 17, Pennsylvania Democratic congressman John Murtha argued that it was time to bring US troops home from Iraq. (Econ, 11/26/05, p.35) 2005 Nov 18, In Pennsylvania an oil painting by Jackson Pollock and a silkscreen by Andy Warhol were stolen from the Everhart Museum by thieves who shattered a glass door in the back of the building. The thieves had disappeared by the time police arrived, four minutes after the alarm sounded at 2:30 2005 Dec 6, Philadelphia won the first NHL scoreless game that was decided by a shootout, beating 2005 Dec 20, A US federal court in Pennsylvania ruled it was unconstitutional to teach schoolchildren the intelligent design theory of life as an alternative to evolution, dealing a blow to religious conservatives. Local parents had sued the Dover, Pa., school board after the board required that ninth-grade biology students be read a statement critical of evolution. (AFP, 12/21/05)(SFC, 12/21/05, p.A1) 2005 Dec 23, In a NYC probe, first reported by the Daily News in October, authorities confirmed this week that investigators found paperwork indicating that bones of British broadcaster Alistair Cooke had been removed and sold by Biomedical Tissue Services, before he was cremated in 2004. Human bone, skin and tendons were allegedly removed from the bodies of hundreds of others without required permission from their families. The Brooklyn case stemmed from a deal struck between Michael Mastromarino (42), a Fort Lee, NJ, dentist who started Biomedical Tissue Services, and Joseph Nicelli (49), an embalmer and funeral parlor operator from Staten Island. In 2006 seven funeral directors pleaded guilty to undisclosed charges and agreed to cooperate with investigators. In 2008 Mastromarino pleaded guilty to hundreds of counts of abusing corpses, forgery, theft and other allegations stemming from the operation, which he ran with 3 Philadelphia (AP, 12/23/05)(SFC, 2/24/06, p.A2)(SFC, 10/19/06, p.A7)(SFC, 8/30/08, p.A2) 2006 Jan 3, In Pennsylvania the Dover School Board rescinded its policy of presenting intelligent design as an alternative to evolution in high school biology (SFC, 1/4/06, p.A2) 2006 Jan 4, In a triple-overtime game that began Jan. 3 and finished after midnight, No. 3 Penn State beat No. 22 Florida State 26-23 in the Orange Bowl. 2006 Jan 25, It was reported that Wyoming rancher Allen Cook (57), with no connection to the University of Pittsburgh, has given the school 4,700 acres of land littered with dinosaur fossils. 2006 Feb 5, In Detroit, Mich., the Pittsburgh Steelers won the Super Bowl over the Seattle Seahawks 2006 Feb 16, Pennsylvania Sen. Arlen Specter asked the Senate Ethics Committee to investigate whether a top aide improperly helped direct nearly $50 million in Pentagon spending to clients represented by her husband. His request followed a USA TODAY report that he secured $48.7 million in projects for six clients of the aide's spouse's firm. 2006 Feb 23, A New Zealand teenager hacked into the University of Pennsylvania computer system. Owen Thor Walker (18), known by his online name "AKILL," also was linked to a network accused of infiltrating 1.3 million computers and skimming millions of dollars from victims' bank accounts. In 2008 Walker was ordered to pay more than $11,000 in fines but avoided a conviction so that he can help police solve computer 2006 Apr 12, Police checking on a home in Leola, Pennsylvania, discovered a gruesome scene: the bodies of six people, some wrapped in sheets and blankets in the basement, and blood, bone fragments and a hammer upstairs. Jesse Dee Wise (21) was charged the next day for the murder of 6 relatives. (AP, 4/13/06)(SFC, 4/14/06, p.A3) 2006 May 11, The Philadelphia City Council unanimously approved a plan to blanket the city's 135 square miles with a high-speed wireless Internet connection, a measure the mayor is expected to sign soon. 2006 Jun 29, East Coast rains, which began over the weekend, have been blamed for five deaths in Pennsylvania, four in Maryland, one in Virginia and three in New 2006 Jul 11, The American League edged the National League 3-2 in the All-Star Game in 2006 Jul 13, Hazleton, Pa., passed Mayor Louis Barletta’s Illegal Immigration Relief Act in an effort to get rid of undocumented immigrants. In August federal lawsuits were filed against Hazleton and other local governments for attempting to regulate immigration. A 1976 US Supreme Court decision said regulation of immigration is exclusively a federal power. In 2007 a federal judge struck down the Hazleton anti-illegal (SFC, 8/16/06, p.A5)(SFC, 7/27/07, p.A13) 2006 Jul 18, A heat wave in the US left at least 7 people dead including 5 in Oklahoma and 2 in (SFC, 7/19/06, p.A2) 2006 Aug 4, In Philadelphia Danieal Kelly (14), a disabled girl, was found dead in her mother's squalid house covered with bone-deep, maggot-infested bedsores. She weighed 42 pounds. In 2008 4 social workers were among 9 people charged in relation to her death. In 2008 Andrea Kelly, the mother, was charged with murder and Daniel, the father, was charged with child endangerment. Both parents retained lawyers who filed suits against their criminal co-defendants, blaming them for the girl's demise. In 2009 mother Andrea Kelly pleaded guilty and was sentenced to 20-40 years in prison. In 2010 case worker Julius Murray was sentenced to 11 years in prison on fraud and obstruction in the case. He had skipped visits and still faced involuntary manslaughter p.A4)(SFC, 6/12/10, p.A9) 2006 Sep 6, Philadelphia’s Art Commission voted 6-2 to move a 2,000-pound bronze statue of Rocky Balboa, commissioned by actor Sylvester Stallone, out of storage and onto a street-level pedestal near the steps of the Philadelphia Museum of Art. (SFC, 9/7/06, p.A2) 2006 Sep 17, In Pennsylvania 5 Duquesne basketball players were shot and wounded during an apparent act of random violence on campus. As of 2007 two alleged gunmen and two women who allegedly helped facilitate the shooting awaited 2006 Oct 2, In Nickel Mines, Pennsylvania, Charles Carl Roberts IV (32), a local truck driver, lined at least 11 girls against a blackboard and shot them in the head at a one-room Amish schoolhouse in Lancaster County. He shot himself as police stormed the schoolhouse. Two young students were killed, along with a female teacher's aide who was slightly older than the students. Seven others, most shot at point-blank range, were taken to hospitals, and two of them died early the next day. (AP, 10/3/06)(SFC, 10/3/06, p.A1)(Econ, 10/7/06, 2006 Oct 4, A Philadelphia jury awarded a woman $1 million and her husband $500,000 in compensatory damages after finding that Wyeth's hormone replacement drug Prempro was a cause of her breast cancer. In the first federal Prempro trial, a jury last month in Little Rock, Arkansas found Wyeth was not negligent and had adequately warned patients and doctors of the cancer risk associated with the drug. Wyeth faced some 5,000 lawsuits involving its hormone replacement drugs. 2006 Oct 13, A jury in Philadelphia said US retail giant Wal-Mart must pay 78 million dollars for violating labor laws in Pennsylvania. (SFC, 10/14/06, p.C1) 2006 Oct 20, In Pennsylvania 24 rail cars carrying ethanol derailed and 9 caught fire on a bridge over the Beaver River in New Brighton, 25 miles northwest of (SSFC, 10/22/06, p.A5) 2006 Nov 16, A state regulatory board approved Gov. Ed Rendell's proposal to make deeper cuts in mercury emissions from Pennsylvania's coal-fired power plants, despite opposition from power plants and mining companies. 2006 Dec 20, Pennsylvania cleared the way for 2 slot machine casino licenses in Philadelphia (SFC, 12/21/06, p.A3) 2006 Dec 22, Rafael Robb (56), tenured economics professor at the Univ. of Pennsylvania, bludgeoned his wife (39) to death in Norristown. In 2007 he pleaded guilty to (SFC, 11/27/07, p.A8) 2006 Dec 29, In Allentown, Pa., a fire swept through 4 downtown row houses killing 5 people. An extension cord overload was blamed. (SFC, 12/30/06, p.A3) 2006 An auto accident in Pennsylvania that left 2 men dead was later attributed to a defective replacement tire from China. In 2007 it was estimated that some 450,000 tires imported by Foreign Tire Sales Inc. of New Jersey from Hangzhou Zhongce Rubber Co. were defective. (WSJ, 6/26/07, p.A1) 2007 Feb 12, In Philadelphia, Penn., 3 men were shot to death in a marketing company conference room and another was critically injured by a gunman who killed himself as police closed in. The gunman had put a gig sum in a (AP, 2/13/07)(WSJ, 2/14/07, p.A1) 2007 Feb 15, Hundreds of drivers became stranded on a stretch of eastern Pennsylvania that had been hit by a monster storm. The National Guard was called in to deliver food and other necessities to a 50-mile line of vehicles trapped on I-78. (WSJ, 2/16/07, p.A1)(AP, 2/16/08) 2007 Feb 16, A thick layer of ice kept major highways closed, a day after hundreds of drivers became stranded on a stretch of eastern Pennsylvania that had been hit by a monster storm. 2007 Feb 17, In southwestern Pennsylvania fire swept through a house in Waynesburg, killing six young children and a woman and injuring one other person. 2007 Jun 19, James Cockayne (21) of New Hope, Pa., was beaten and stabbed to death in the Virgin Islands. 3 men, Anselmo Boston, Kamal Thomas and Jahleel Ward, were arrested after the parents of Cockayne appeared on US news programs and accused Virgin Islands detectives of botching an investigation into their son's death. On Oct 10, 2008, Ward was found guilty of first-degree murder and other charges. Anselmo Boston and Kamal Thomas were found guilty on two counts each of third-degree assault, among other charges. (AP, 10/6/08)(AP, 10/10/08) 2007 Jul 8, In Pennsylvania Gov. Ed Rendell ordered a range of government services shutdown after last minute negotiations failed to break a budget stalemate. The shutdown took about 24,000 workers off the job. A budget deal was hammered out the following night. (AP, 7/9/07)(SFC, 7/9/07, p.A3)(AP, 7/8/08) 2007 Jul 10, Railroad Development Corp., a Pittsburgh-based railroad company under Henry Posner III, planned to shut down Guatemala's only train service after years of fighting thieves, squatters and government-backed lawsuits. Posner expected to take his case to int’l. arbitration under CAFTA with a demand for $65 million in lost revenues and (AP, 7/10/07)(WSJ, 1/23/07, p.A14) 2007 Aug 15, Pennsylvania Superior Court Judge Michael Thomas Joyce, an appeals court judge, was indicted on charges of scamming $440,000 from insurers by claiming he suffered debilitating injuries in a car crash, even while he golfed, skated and went scuba diving. 2007 Aug 27, Police arrested Paul Devoe III (43) in Shirley, NY, following 5 recent murders in Texas and one in Pennsylvania. On December 19, 2007, the Texas Travis County District Attorney announced his office's intention to pursue the death penalty. 2007 Sep 10, It was reported that John Kanzius of Erie, Pa., had accidentally discovered a way to burn salt water when he tried to desalinate seawater with a radio-frequency generator he developed to treat cancer. He discovered that as long as the salt water was exposed to the radio frequencies, it would burn. 2007 Sep 13, In Philadelphia police chief Sylvester Johnson acknowledged that police alone could not quell the city’s deadly violence and planned to introduce “Call to Action: 10,000 Men," an effort to get volunteers on the streets as of Oct 21. (SFC, 9/14/07, p.A5) 2007 Sep 17, The Roman Catholic Diocese of Pittsburgh said it has created a $1.25 million fund to settle 32 lawsuits alleging abuse or injury by priests. 2007 Oct 4, In Philadelphia Mustafa Ali (36), a convicted bank robber, shot and killed two armored car guards servicing an ATM outside a bank. Several schools were locked down amid a massive manhunt for the gunman, who was arrested the next day. (AP, 10/4/07)(AP, 10/6/07) 2007 Oct 12, In Norristown, Pa., Michele Cossey (46), the mother of a 14-year-old who authorities say had a cache of guns, knives and explosive devices in his bedroom for a possible school attack, was charged with buying her son 3 weapons. Authorities said the teenager felt bullied and tried to recruit another boy for a possible attack at Plymouth Whitemarsh High School. 2007 Oct 26, Friedman Paul Erhardt (63), television's "Chef Tell," died in Upper Black Eddy, 2007 Oct 29, Democrats Barack Obama and John Edwards sharply challenged Sen. Hillary Rodham Clinton's candor, consistency and judgment in a televised debate in 2007 Oct 30, It was reported that John Murtha, US Democratic Congressman from Johnstown, Pa., and chairman of the House Appropriations Subcommittee on Defense, had steered at least $600 million in earmarks to his district over the past 4 years. Since 1992 he has sent some $2 billion to his home (WSJ, 10/30/07, p.A1) 2007 Nov 3, Boss, a robotic Chevrolet Tahoe from Carnegie Mellon Univ., won the annual DARPA sponsored race in San Bernadino County, Ca. 6 of 11 starting vehicles finished the 10-mile race, designed to simulate a town. No car finished the first race in 2004. (Econ, 11/10/07, p.100) 2007 Nov 12, It was reported that a donor had given a staggering $100 million to the Erie Community Foundation in Pennsylvania, and all of the charities would receive a share. 2007 Nov 12, A new study said US researchers have developed a method of producing hydrogen gas from biodegradable organic material, potentially providing an abundant source of this clean-burning fuel. The method used by engineers at Pennsylvania State University combines electron-generating bacteria and a small electrical charge in a microbial fuel cell to produce hydrogen gas. 2007 Nov 30, New Zealand officials said police have questioned the suspected teenage kingpin of an international cyber crime network accused of infiltrating 1.3 million computers and skimming millions of dollars from victims' bank accounts. Earlier this month, Ryan Goldstein, 21, of Ambler, Pa., was indicted in the case. Authorities allege that the New Zealand suspect and Goldstein were involved in crashing a University of Pennsylvania engineering school server Feb. 23, 2006. On Feb 29 Owen Thor Walker (18) was charged with two counts of accessing a computer for dishonest purpose, damaging or interfering with a computer system and possessing software for committing crime, and two counts of accessing a computer system without authorization. (AP, 11/30/07)(AP, 2/29/08) 2007 Dec 16, Street and highway crews were at work trying to clear roads across the Great Lakes states into New England as a storm blamed for three deaths spread a hazardous mix of snow, sleet and freezing rain. The storm was blamed for at least 10 deaths including 4 in Indiana, 2 in Michigan and Wisconsin, one in Pennsylvania and one in Nova Scotia. (AP, 12/16/07)(SFC, 12/18/07, p.A19) 2007-2008 Rep. John Murtha, D-Pa., sponsored $14.7 million in defense earmarks for Kuchera Defense Systems, a campaign donor. The Pentagon went along with it, despite the fact that two convicted drug dealers had been deeply involved with the company. 2008 Jan 30, In Philadelphia Nurse Lee Cruceta (35) admitted he cut body parts from 244 corpses and helped forge paperwork so the parts, some of them diseased, could be used in unsuspecting patients. Cruceta has also pleaded guilty to related charges in New York and negotiated pleas to serve concurrent sentences of 6 1/2 to 20 years. 2008 May 1, Philadelphia’s Mayor Michael Nutter and police commissioner hoped to have 200 more police officers on the streets by this time as part of a new 33-page crime-fighting plan. Murders in the city had reached 392 in 2007. Gov. Ed Rendell agreed to help foot the bill. (Econ, 2/9/08, p.33) 2008 Mar 27, A US appeals Court in Philadelphia overturned the death sentence of Mumia Abu Jamal, who had been convicted of killing Officer Daniel Faulkner on Dec 9, (SFC, 3/28/08, p.A4) 2008 Apr 7, In Ohio 9 mortgage lenders agreed to modify adjustable-rate mortgages for borrowers facing foreclosure. In Pennsylvania mortgage companies and consumer advocates opened talks to help cash-strapped homeowners avoid foreclosure. Last week Maryland’s Gov. signed a measure creating a 150-day moratorium on foreclosures. (WSJ, 4/8/08, p.A4) 2008 Apr 22, In Pennsylvania Hillary Clinton won the primary with about 55% of the vote to 45% 2008 May 1, Philadelphia’s Police Commissioner Charles H. Ramsey announced a major reorganization of the department's command structure and the addition of nearly 250 officers on street patrols, part of a crime-fighting strategy he said was already showing results. Mayor Michael Nutter and the police commissioner had hoped to have 200 more police officers on the streets by this time as part of a new 33-page crime-fighting plan. Murders in the city had reached 392 in 2007. Gov. Ed Rendell agreed to help foot the bill. 2008 May 3, In Philadelphia police officer Liczbinski was shot with an assault rifle after a robbery. One suspect was fatally shot by police soon after, another was arrested the next day and a third was captured May 7. 2008 May 5, Philadelphia police stopped the suspects' car while investigating a triple shooting. No weapons were found in the car or on the suspects, but officers said they had seen them shoot three people on a drug corner moments earlier. Video shot by WTXF-TV from a helicopter showed officers gathered around the vehicle as they pulled three men out. About a half-dozen officers held two men on the ground on the driver's side. Both were kicked repeatedly, while one was punched; one also appeared to be struck with a baton. A review of the video led to the firing of 4 officers with disciplinary action for 4 others. In 2009 a grand jury cleared the officers involved saying no excessive force (AP, 5/8/08)(WSJ, 5/20/08, p.A2)(SFC, 8/7/09, 2008 May 13, EarthLink said it is pulling out of its high-speed Internet network in Philadelphia, and that it would shut down the operation on June 12. (SFC, 5/14/08, p.C3) 2008 Jun 12, Deaths due to the heat wave across the US East Coast climbed past 30 with at least 15 dead in Philadelphia and 7 in NYC. (WSJ, 6/13/08, p.A2) 2008 Jul 9, In western Pennsylvania the bodies of 22-year-old Ashley Guarino, her 2-year-old daughter Dreux and 11-month-old son Orlando Jr. were found by relatives. Orlando Maurice Guarino (38) was arrested the next day and charged with the murders of his wife and children. 2008 Jul 14, In Pennsylvania Luis Ramirez (25), an illegal Mexican migrant worker, died in Shenandoah after being beaten by white youths. 4 young men were charged and found responsible for the fight, but most of the federal charges against them were dropped. Local police were later accused of tampering with evidence and witnesses or lying to the FBI. In 2010 Derrick Donchak and Brandon Piekarsky were convicted for a federal hate crime. In 2011 former police chief Matthew Nestor was found guilty of falsifying his police report, a charge that carries up to 20 years in prison. Officer William Moyer was found guilty of lying to the FBI but was acquitted of four other counts. Officer Jason Hayes, who's engaged to the mother of one of Ramirez's attackers, was acquitted of both charges against him. In all, the jury convicted on two of nine counts. On Feb 23, 2011, Donchak and Piekarsky were sentenced to nine years each in prison for roles in the death of Ramirez. 10/15/10, p.A6)(AP, 1/27/11)(Reuters, 2/24/11) 2008 Jul 15, In Pennsylvania Betty Schirmer (56) was killed in an apparent car accident. In 2010 her husband, Pastor Arthur Burton Schirmer, was charged with killing her and staging the car accident. The charge also prompted an investigation into the suspicious death of his 1st wife, Jewel Schirmer, in 1999. 2008 Jul 25, Randy Pausch (47), a Carnegie Mellon University computer scientist, died at his home in Virginia. His "last lecture" in September 2007, about facing terminal cancer, has become an Internet sensation and a best-selling 2008 Oct 3, The Great Lakes Governors (Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, Wisconsin) applauded President George W. Bush for signing a joint resolution of Congress providing consent to the Great Lakes-St. Lawrence River Basin Water Resources Compact. It barred new diversions beyond the Great Lakes Basin. 2008 Oct 17, In Philadelphia college student Jocelyn Kirsch (23) was sentenced to five years in prison and ordered to pay more than $100,000 in restitution. She and her former boyfriend, Edward Anderton, had stolen the identities of friends and neighbors in 2006 and 2007 to net more than $116,000 in goods and services. Anderton’s sentence was pending. 2008 Oct 29, The Philadelphia Phillies won the baseball World Series over the Tampa Bay Rays 4-3 with the conclusion of Game 5, which had been stopped by rain 2 days (SFC, 10/30/08, p.D1) 2008 Nov 6, Philadelphia’s Mayor Nutter said a budget deficit crises will force the city to close libraries and swimming pools, suspend planned tax reductions, cut more than 800 jobs and trim salaries to deal with a $1 billion (SFC, 11/7/08, p.A7) 2008 Nov 19, FBI agent Sam Hicks was shot and killed while serving a warrant at a home near Pittsburgh, during a roundup of drug suspects in the greater Pittsburgh area. Christina Korbe was charged with homicide. Her husband, Robert Korbe, was one of 35 people charged in a 27-count (AP, 11/19/08)(SFC, 11/20/08, p.A4) 2008 Dec 26, In Philadelphia a duplex fire apparently caused by fuel spilling from an overfilled kerosene heater killed seven people, including 3 kids, in a basement that had only one exit. 2008 Dec 31, SF ended the year with 98 homicides. In Milwaukee, Wisc., the total number of homicides dropped 32%, from 105 in 2007 to 71 in 2008, the lowest number since 1985. Detroit had 344 slayings, a 13% drop from the 396 in 2007; Philadelphia's 332 killings were a 15% drop from the 392 in 2007; and the 234 homicides in Baltimore were 17% less than the 392 the year before. Cleveland recorded 102 homicides in 2008, down from a 13-year high of 134 in 2007. Homicides in New York rose 5.2%, to 522 from 496 the year before. Slayings in Los Angeles were down to 376 in 2008 compared to 400 the prior year. Preliminary data in Chicago showed 508 homicides were reported in 2008, the first time the city had more than 500 murders since 2003 and about 15% more than the 442 homicides reported in 2007. Washington, D.C., ended 2008 with 186 homicides, up from 181 in 2007. (SFC, 1/2/09, p.1)(AP, 1/3/09) 2009 Jan 7, The SEC charged Joseph S. Forte of Broomall, Pennsylvania, an investment fund manager, with running a Ponzi scheme since at least 1995. Losses to investors were estimated at $50 million. 2009 Jan 16, Artist Andrew Wyeth (b.1917), American artist, died at his home in the Philadelphia suburb of Chadds Ford. He had portrayed the hidden melancholy of the people and landscapes of Pennsylvania's Brandywine Valley and coastal Maine in works such as "Christina's World." 2009 Jan 22, US federal agents raided Kuchera Industries and Kuchera Defense systems, 2 small Pennsylvania defense contractors. They were given millions in federal funding by Rep. John Murtha, chairman of the defense appropriations committee. In 2007 the WSJ identified Murtha as the largest earmarker in the House. (WSJ, 1/22/09, p.A6) 2009 Feb 1, In Super Bowl XLIII at Tampa, Florida, the Pittsburgh Steelers beat the Arizona (SFC, 2/2/09, p.A1) 2009 Jan 26, Two Pennsylvania judges were charged with taking millions of dollars in kickbacks to send teenagers to two privately run youth detention centers. Prosecutors later said Luzerne County Judges Mark Ciavarella (58) and Michael Conahan (56) took $2.6 million in payoffs to put juvenile offenders in lockups run by PA Child Care LLC and a sister company, Western PA Child Care LLC. Conahan soon pleaded guilty to a single count of racketeering. The “kids for cash" trial against Ciavarella began in 2011. On Feb 18, 2011, Ciavarella was convicted of racketeering. On Aug 11, 2011, Ciavarella was sentenced to 28 years in prison. On Sep 23 Conahan was sentenced to 17.5 years in prison. On Nov 4, 2011, Robert Powell, the former owner of 2-for profit juvenile detention centers, was sentenced to 18 months in prison for his role in the scheme. In 2014 builder Robert Mericle was sentenced to a year in jail and fined $250k for his role in the kids for cash scandal. On August 10, 2015, a federal judge approved a $4.75 million settlement between Powell and some 2,400 juveniles. (AP, 2/11/09)(SFC, 2/7/11, p.A4)(SFC, 2/19/11, p.A6)(SFC, 8/12/11, p.A5)(SFC, 9/24/11, p.A4)(SFC, 11/5/11, p.A5)(SFC, 4/26/14, p.A6)(SFC, 8/13/15, p.A6) 2009 Feb 19, In Pennsylvania Roger Leon Barlow (19) was charged with setting 9 fires in arson-prone Coatesville, 35 miles west of Philadelphia. (SFC, 2/20/09, p.A10) 2009 Feb 20, In Wampum, Pennsylvania, Jordan Brown (11) shot his father's pregnant fiancee, Kenzie Marie Houk (26), in the back of the head as she lay in bed. He then put his youth model 20-gauge shotgun back in his room before going out to catch his school bus. On March 29, 2010, a judge ruled that boy will be tried as an adult. (AP, 2/22/09)(SFC, 3/30/10, p.A10) 2009 Feb 21, The Journal Register Co., a Yardley, Pa.-based company, filed for bankruptcy protection. The company owned 2o daily and 159 nondaily newspapers with some 3,500 employees. (SSFC, 2/22/09, p.A8) 2009 Mar 2, A massive late winter snow storm roared out of the Southeast and into the Northeast overnight, idling hundreds of flights and making the morning rush treacherous as motorists contended with nearly a foot of snow in spots. Some 950 flights were canceled at the three main New York area airports, an almost 300 canceled in Philadelphia. (AP, 3/2/09)(SFC, 3/3/09, p.A5) 2009 Mar 12, Leonore Annenberg (b.1918), the widow of billionaire publisher Walter Annenberg (d.2002), died in southern California. She had continued directing the philanthropy of the Annenberg Foundation based in Radnor, a suburb of Philadelphia, Pa. (SFC, 3/13/09, p.B8) 2009 Mar 14, In Coatesville, Pennsylvania, the 20th arson fire this year was set, one day after Roger Leon Barlow (19) was held for trial in connection with fires set between Jan 2 and Feb 3. (SSFC, 3/15/09, p.A10) 2009 Mar 16, Vincent Fumo (65), former Pennsylvania state senator, was convicted of 137 counts of corruption for schemes that defrauded the state senate of more than (WSJ, 3/17/09, p.A6) 2009 Apr 4, In Pittsburgh, Pa., Richard Poplawski (23) shot and killed 3 police officers, who were responding to a domestic violence disturbance. Poplawski received gunshot wounds in his legs and was charged with 3 counts of murder. The shooting began following an argument between Poplawski and his mother over a dog urinating in their house. On June 28, 2011, a jury sentenced Poplawski to death. (SSFC, 4/5/09, p.A12)(SFC, 4/6/09, p.A5)(SFC, 2009 Apr 28, Veteran Republican Arlen Specter of Pennsylvania switched parties with a suddenness that seemed to stun the Senate, a moderate's defection that pushed Democrats to within a vote of the 60 needed to overcome filibusters and enact President Barack Obama's top legislative priorities. 2009 May 7, Seven Pittsburgh-area ACORN workers were charged with falsifying voter registration forms, with six accused of doing so to meet the group's alleged quota system before last year's general election. 2009 May 23, It was reported that millions of bats in at least 7 US states (Connecticut, New York, Massachusetts, Pennsylvania, Vermont, Virginia and West Virginia) have died from white-nose syndrome, a fungal diseases. In 2011 the fungus Geomyces destructans was identified as the cause. The fungus responsible was later identified as Pseudogymnoascus (Econ, 5/23/09, p.36)(SFC, 10/28/11, p.A18)(SSFC, 2009 Jun 10, In Pennsylvania a car fleeing a robbery scene jumped a curb in Philadelphia, smashed into a crowd and killed three young children. One robber had fled on the motorcycle and the other in a car. Both were arrested. Latoya Smith (22), the mother and aunt of two of the children, died the next days from her injuries. (AP, 6/11/09)(AP, 6/12/09) 2009 Jul 14, In Pennsylvania former lawmaker Vincent Fumo was sentenced to less than 5 years in prison for misappropriating millions from the state and two (SFC, 7/15/09, p.A6) 2009 Aug 4, In Bridgeville, Pennsylvania, George Sodini (48) sprayed bullets into a fitness class filled with women, killing three and then himself. He kept a Web page in which he wrote about years of rejection by women and an earlier plan for violence at the gym. 2009 Aug 6, Ethiopia’s Federal High Court issued the guilty verdicts against 13 men, including a US-based professor, convicted in absentia for plotting to overthrow the government. Berhanu Nega, Ethiopian-born professor with US nationality and teacher of economics at Philadelphia's Bucknell Univ., was accused of masterminding a plan to topple PM Meles 2009 Aug 14, Real estate lender Colonial BancGroup Inc. was shut down by federal officials in the biggest US bank failure this year. The FDIC, which was appointed receiver of the Montgomery, Ala.-based Colonial and its about $25 billion in assets, said the failed bank's 346 branches in Alabama, Florida, Georgia, Nevada and Texas will reopen at the normal times starting on Aug 15 as offices of Winston-Salem, N.C.-based BB&T. Regulators also closed four other banks: Community Bank of Arizona, based in Phoenix; Union Bank, based in Gilbert, Ariz.; Community Bank of Nevada, based in Las Vegas; and Dwelling House Savings and Loan Association, located in Pittsburgh. The closures boosted to 77 the number of federally insured banks that have failed in 2009. 2009 Aug, Pennsylvania Central Bucks East High School English teacher Natalie Munroe started a blog for friends and family in suburban Philadelphia. Munroe blogged about 85 times and only about 15 to 20 of the posts involved her being a teacher. In 2011 she was suspended for the profanity-laced blog in which she called her students "disengaged, lazy whiners," and daring to ask: “Why are today's students unmotivated, and what's wrong with calling them out?" 2009 Sep 16, In Pennsylvania Andrew Mogilyansky, a wealthy Russian-American car exporter from suburban Philadelphia, was sentenced to 8 years in prison for procuring girls from a Russian orphanage to have sex with them. (SFC, 9/17/09, p.A7) 2009 Sep 21, The Philadelphia Daily News reported that police officer Thomas Strain was put on desk duty this month because of braids, even though the paper reported dozens of black officers wear cornrows. The white officer, who came to work with cornrows, was ordered by a black superior to get a haircut because the braids violated department standards. 2009 Sep 24, In Pennsylvania US Pres. Obama hosted a 2-day meeting of the G20 as it opened in (SFC, 9/26/09, p.A4) 2009 Sep 25, In Pennsylvania police arrested 83 people during protests at the meeting of the G20 Pittsburgh. A “People’s March" attracted nearly 5.000 people. The G20 ended a 2-day meeting and reached a series of agreements aimed at navigating the world out of recession. The alliance announced that it will replace the G7 as the main forum for int’l. economic cooperation. The G7 will now concentrate mainly on security issues. 10/3/09, p.88)(Econ, 10/10/09, p.51) 2009 Sep, George Zimmermann, a Pennsylvania landowner, filed suit against Atlas Energy Inc. for polluting his soil and water in an attempt to link a natural gas drilling technique with environmental contamination. Atlas was exploiting the Marcellus Shale, a vast gas reserve that underlies about two-thirds of Pennsylvania and parts of West Virginia, Ohio and New York State. Experts estimated that it contains enough natural gas to meet total US demand for at least a decade. Baseline tests on Zimmermann's water a year before drilling began were "perfect," he said. In June, water tests found arsenic at 2,600 times acceptable levels, benzene at 44 times above limits and naphthalene five times the federal standard. 2009 Oct 15, Colleen R. LaRose (46), a self-described "Jihad Jane," was arrested in Philadelphia. LaRose was later accused, in an indictment filed March 9, 2010, of actively recruiting fighters, as well as agreeing to murder Swedish artist Lars Vilks, marry a terrorism suspect so he could move to Europe and martyr herself if necessary. 2009 Nov 3, In Philadelphia, Pa., transit workers went on strike after rejecting a proposed contract that included an 11.5% wage increase over 5 years. (SFC, 11/4/09, p.A6) 2009 Nov 4, The New York Yankees beat the Philadelphia Phillies 7-3 in Game 6, finally seizing the World Series crown, the team's first since winning three straight from 1998-2000, making it championship No. 27. 2009 Nov 9, Pennsylvania Gov. Ed Rendell said the Philadelphia transit strike has ended and that system would be up and running for the morning commute. (SFC, 11/9/09, p.A8) 2009 Dec 6, In Pennsylvania parolee Ronald Robinson (32) fatally shot a man in Penn Hills over a $500 drug debt and then shot and killed police officer Michael (SFC, 12/8/09, p.A12) 2009 Dec 10, Pennsylvania police charged Alfonso Frank Frazetta (52) with theft, burglary and trespass after he was caught loading artwork into his trailer and SUV. He had used a backhoe to break into a museum owned by his father, fantasy artist Frank Frazetta (b.1928) loading artwork. (SFC, 12/11/09, p.A11) 2010 Jan 13, R&B singer Teddy Pendergrass (b.1950) died of colon cancer in suburban Philadelphia. He was one of the most electric and successful figures in music until a 1982 car crash left him in a wheelchair. 2010 Jan 25, In Pennsylvania Andrea Curry-Demus (40) was found to be mentally ill but guilty of 2nd degree murder and kidnapping for luring a pregnant teenager to her apartment, cutting out the baby and killing the mother. The infant, now 18 months old, was living with relatives. (SFC, 1/26/10, p.A4) 2010 Feb 5, In Pennsylvania about 18,000 people turned out before dawn for the 18th Wing Bowl, an eating competition dubbed the world's biggest, and an annual celebration of Philadelphia's raucous sports-crazed culture. 2010 Feb 8, John Murtha (b.1932), Pennsylvania’s Democratic representative, died in Arlington, Va., following complications from gall bladder surgery. He had won a special House election in 1974 to become the first Vietnam veteran to serve in Congress. (SFC, 2/9/10, p.A6) 2010 Feb 12, In Pennsylvania Max Ray Vision, formerly Max Ray Butler, of San Francisco was sentenced to 13 years in prison and ordered to pay $27.5 million to the banks and credit card companies that he victimized. In 2009 Butler (36) had identified himself in court as “Max Vision," the name he gave himself in the 1990s when he became a superstar in the computer security community. 2010 Mar 13, A storm battered parts of Pennsylvania, New Jersey, New York and Connecticut with gusts of up to 70 mph. 2010 Jun 25, In Richmond, Va., Quanis Phillips, a co-defendant with Philadelphia Eagles’ QB Michael Vick in a 2007 federal dogfighting charge, died in a shooting. Vick had pleaded guilty to the 2007 charges. Police said Vick has not been ruled out as suspect or person of interest in the shooting which occurred shortly after a birthday party for Vick had ended at a club. An investigation was ongoing. 2010 Jun 26, Pennsylvania police found the bodies of three men and a woman, each stabbed multiple times, in the brick twin house in Northampton. Steven Zernhelt (53), a married father of three, was stabbed to death as he responded to screams next door. Police discovered the bodies after responding to a car crash about a half-mile from the house. The driver, Eric Ballard (36), was covered in blood and police knew it wasn't all from the crash. Ballard was charged the next day with the stabbing murder of his former girlfriend and 3 others. (AP, 6/27/10)(SFC, 6/28/10, p.A4) 2010 Jul 6, The East Coast roasted under an unrelenting sun as record-setting temperatures soared past 100 from Virginia to Massachusetts, utility companies cranked up power to the limit to cool the sweating masses and railroad tracks were so hot commuter trains had to slow down. The temperature reached 100 in Philadelphia toppling a record set in (AP, 7/6/10)(SFC, 7/7/10, p.A5) 2010 Jul 7, In Philadelphia, Pa., a 250-foot barge collided on the Delaware River with a stalled amphibious sightseeing boat. 2 visitors from Hungary were killed. In 2011 tug pilot Matt Devlin agreed to plead guilty to involuntary manslaughter following evidence that he was talking on a cell phone during the accident. (AP, 7/9/10)(SFC, 7/15/11, p.A7) 2010 Jul 19, Despite being rebuffed twice by the US Supreme Court, five states (Michigan, Wisconsin, Ohio, Minnesota and Pennsylvania) filed suit with a lower court demanding tougher federal and municipal action to prevent Asian carp from overrunning the Great Lakes and decimating their 2010 Sep 9, In Pennsylvania Kraft worker Yvonne Hiller of northeast Philadelphia shot and killed two co-workers after she was suspended from a Kraft Foods plant. 2010 Oct 10, Solomon Burke (b.1940), the larger-than-life "King of Rock and Soul," died at Amsterdam's Schiphol Airport. The Philadelphia-born singer was revered as one of music's greatest vocalists but never reached the level of fame of those he influenced. He joined Atlantic in 1960 and went on to record a string of hits in a decade with the label. He wrote "Everybody Needs Somebody to Love" in 1964 and it was later featured in the Dan Aykroyd and John Belushi movie "The Blues 2010 Oct 23, The SF Giants won a trip to the World Series. In Pennsylvania Juan Uribe hit a tiebreaking homer off Ryan Madson with two outs in the eighth inning and the Giants held off the Phillies 3-2 in Game 6 of the NL championship series. This finished off the Phillies' bid to become the first NL team in 66 years to win three straight pennants. (AP, 10/24/10)(SSFC, 10/24/10, p.1) 2010 Nov 2, Iowa (Terry Branstad), Kansas (Sam Brownback), Maine (Paul LePage), Michigan (Rick Snyder), New Mexico (Susana Martinez), Ohio (John Kasich), Oklahoma (Mary Fallin), Pennsylvania (Tom Corbett), Tennessee (Bill Haslam), Wisconsin (Scott Walker), Wyoming (Matt Mead) all replaced the Democratic governors with Republicans. Snyder (R) defeated Michigan Gov. Jennifer Granholm (D) by bragging about his managerial (Econ, 11/6/10, p.45) 2010 Nov 13, In Erie, Pa., an apparent suicide-murder by a father (29) left the mother and 2 (SSFC, 11/14/10, p.A14) 2011 Jan 18, Philadelphia Gas Works employee, Mark Keeley (19), was killed in a gas main explosion. 6 people were sent to the hospital with 3 in critical (SFC, 1/20/11, p.A6) 2011 Jan 19, In New Castle, Pa., Ljuba Novosel shot and killed her son (12) and elderly mother (81) before turning the gun on herself. (http://tinyurl.com/4h8hja5)(SFC, 1/24/11, p.A4) 2011 Feb 6, In Dallas, Texas, Wisconsin’s Green Bay packers won Super Bowl XLV 31-25 win over the 2011 Feb 8, Claudia Aderotimi (20), a London woman, died at a Philadelphia hospital at 1:32 a.m., some 12 hours after a botched buttocks enhancement at a Hampton Inn near the Philadelphia Int’l Airport. Authorities sought to question Padge Victoria Windslowe, a self-described Goth hip hop singer known as "Black Madam" from Ardmore, Pa., in the death. On June 11, 2015, Windslowe was sentenced to 10 to 20 years in prison. (Reuters, 2/12/11)(SFC, 6/12/15, p.A7) 2011 Feb 10, The Hershey Trust Co. fired board member Robert Reese, a former top Hershey Co. executive. Reese had filed documents in Pennsylvania saying the Hershey Trust has allowed excessive compensation for board members, violations of federal banking regulations and free limousine rides and rounds of golf. 2011 Feb 10, In Allentown, Pennsylvania, a natural gas explosion rocked a downtown neighborhood overnight, leveling two houses and spawning fires that burned for hours through an entire row of neighboring homes. One person was killed, and at least five others were unaccounted for. 2011 Feb 24, A US federal jury convicted Mohammad Reza Vaghari (43), of Broomall Pa., of sending the products to Iran by way of the United Arab Emirates. 2011 Feb, In Pennsylvania Kermit Gosnell, his wife and eight workers were charged in the operation of a clinic in West Philadelphia where illegal late term abortions were performed and where babies born alive and viable were killed. In 2014 the last of two workers in the case were sentenced to 5 to 10 years in prison after pleading guilty and testifying (SFC, 6/27/14, p.A6) 2011 Mar 8, The Archdiocese of Philadelphia said it has suspended 21 priests from active ministry in connection with a grand jury’s Feb 10 accusations that they sexually abused or otherwise acted inappropriately with minors. (SFC, 3/9/11, p.A5) 2011 Mar 8, In central Pennsylvania a farmhouse fire killed 7 of 8 children of Theodore and Janelle Clouse. A propane heater was suspected as the cause. (SFC, 3/10/11, p.A8) 2011 Mar 22, In central Pennsylvania 5 people were killed in an apartment fire in Altoona. (SFC, 3/23/11, p.A4) 2011 Apr 27, The city of Altoona, Pa., enacted a 60-day name change to "POM Wonderful Presents: The Greatest Movie Ever Sold," after the latest film by sarcastic documentarian Morgan Spurlock, in order to make some money and to help Spurlock make a point about the proliferation of advertising in American life. 2011 May 5, A federal judge in Pennsylvania sentenced conman Donald Young (39) to nearly two decades in prison for a $23 million pyramid scheme. (SFC, 5/6/11, p.A8) 2011 May 23, Reputed Philadelphia mob boss Joseph Ligambi and 12 others were indicted with charges of racketeering and gambling. (SFC, 5/24/11, p.A4) 2011 May, Joseph Cohen, Dan Getelman and Jim Grandpre quit the Univ. of Pennsylvania to launch Coursekit, soon rebranded as Lore, a social learning network for the (Economist, 8/25/12, p.52) 2011 Jun 1, Pennsylvania and the city of Philadelphia embarked on a 25-year, $2 billion effort to reduce storm water pollution through eco-friendly measures. (SFC, 6/2/11, p.A6) 2011 Jun 2, In Maryland Sukanya Roy (14) of South Abington Township, Pa., won the 84th Scripps national Spelling Bee. (SFC, 6/3/11, p.A7) Jun 6, Former Pennsylvania congressman Rick Santorum, a social conservative, announced that he is a candidate for the Republican nomination for president. 2011 Jun 18, In Warrington, Pa., Christopher Moyer killed his wife, Irina (39), and their son (7) and then committed suicide on a set of train tracks. Financial problems were suspected. (SSFC, 6/19/11, p.A8) 2011 Jul 4, In Pennsylvania Mark Richard Geisenheyner (51) was killed by a SWAT team in Trainer for shooting 5 people, 2 of them fatally, a day earlier in a suburban Philadelphia home over an insurance fraud scheme. (SFC, 7/5/11, p.A6) 2011 Jul 12, A federal indictment unsealed in St. Louis said The Wheels of Soul motorcycle club, with a "Mother Chapter" in Philadelphia, was responsible for killings, robberies, drug distribution and other crimes. The indictment accused 18 men in seven states of racketeering, with some of the men also accused of crimes that include murder, attempted murder, robbery and kidnapping. 2011 Aug 8, The US Justice department and 4 the attorney generals of California, Illinois, Florida, and Indiana accused Pittsburgh-based Education Management Corp. of paying recruiters to enroll students in an $11 billion (SFC, 8/8/11, p.A5) 2011 Aug 10, Scientists at the University of Pennsylvania reported the first clear success with a new approach for treating leukemia, turning the patients' own blood cells into assassins that hunt and destroy their cancer cells. 2011 Aug 15, In Philadelphia Corey White (22) was shot to death hours after a judge held two people for trial for conspiring to kill him in a murder-for-hire plot on Facebook. (SFC, 8/17/11, p.A6) 2011 Aug 28, In Pennsylvania Leonard John Egland (37) of Fort Lee, Va., an Army officer suspected of killing four people in Pennsylvania and Virginia, was found dead in Bucks County. He had fired a semiautomatic rifle at SWAT team members who discovered his truck and found him before dawn in a trash bin. Officers earlier in the day had found the bodies of Egland's ex-wife, her boyfriend and his child. His former mother-in-law, Barbara Reuhl (66) of Buckingham, was believed to have been killed the previous night. 2011 Sep 8, Tropical Storm Lee dumped heavy rain in the Northeast. The Susquehanna River and its tributaries in New York and Pennsylvania swamped thousands of homes. At least 15 deaths were blamed on the storm and its aftermath: 7 in Pennsylvania, 3 in Virginia, one in Maryland and 4 others when it came ashore on the Gulf Coast a week earlier. (SFC, 9/10/11, p.A6) 2011 Oct 12, The City Council in Harrisburg, Pa., filed for bankruptcy, despite opposition by the Mayor Linda Thompson and state Gov. Tom Corbett. Harrisburg faced $300 million in debt connected to a city-owned rubbish incinerator. (SFC, 10/13/11, p.A8)(Econ, 12/3/11, p.89) 2011 Oct 15, In Philadelphia apartment landlord Turgut Gozleveli found 4 mentally disabled adults held inside a basement boiler room. Police arrested 3 people for kidnapping, false imprisonment and other charges. Linda Ann Weston (51), Eddie Wright (50) and Gregory Thomas (47) were implicated in a broad scheme to steal disability checks from vulnerable people. (SFC, 10/18/11, p.A5) 2011 Oct 20, Pennsylvania Gov. Tom Corbett signed a state law giving him unprecedented power to force Harrisburg to pay off its staggering debt on a $300 million (SFC, 10/21/11, p.A7) 2011 Nov 5, Penn State assistant coach Jerry Sandusky (67) was arrested for 40 sex crimes against boys dating from 1994 to 2005. All of the boys were under the care of the Second Mile Foundation, a charity that Sandusky founded in 1977. (SFC, 11/9/11, p.A12)(http://tinyurl.com/864sytk) 2011 Nov 7, Joe Frazier (67), the boxer who first beat Muhammad Ali in March 1971, died in Philadelphia after a brief battle with liver cancer. (AP, 11/7/11)(Econ, 11/19/11, p.106) 2011 Nov 10, Thousands of enraged Penn State students tore through the streets of State College, Pa., overnight to protest the firing of Joe Paterno after the longtime head football coach was removed from his position effective immediately. The turmoil followed the arrest of former assistant coach Jerry Sandusky, charged with abusing at least eight boys over 15 years. Paterno and Univ. Pres. Graham Spanier, who was also fired, have come under intense pressure because they were also told of at least one incident, but did not alert police. 2011 Nov 16, Oscar Ramiro Ortega-Hernandez (21), a man with an apparent obsession with President Barack Obama, was arrested in Pennsylvania after the Secret Service discovered two bullets struck the White House while the president was away. 2011 Dec 7, In Pennsylvania prosecutors abandoned their 30-year push for the execution of Mumia Abu-Jamal, a former Black Panther convicted in 1982 of killing police Officer Daniel Faulkner. Abu-Jamal (58) will spend the rest of his life in prison. (SFC, 12/8/11, p.A11) 2011 Dec 19, In, Webster, Pennsylvania, police shot and killed Eli Franklin Myers (58) during a standoff hours after he killed East Washington officer John David Dryer during a traffic stop. (SFC, 12/20/11, p.A8) 2011 Skee-ball Inc. (SBI), the Pennsylvania maker of the skee-ball machine, sued the Brooklyn-based Brewskee-ball League for infringing on its century-old trademark. (Econ, 7/19/14, p.29) 2011 In Pennsylvania Gene Carter (39) was sentenced up to 216 years in prison for running a major heroin ring while serving time in a halfway house. In 2015 an appeals court overturned the sentence calling it unreasonable and (SFC, 9/5/15, p.A7) 2012 Jan 22, Joe Paterno (85), the longtime Penn State coach, died. He won more games than anyone in major college football but was fired amid a child sex abuse scandal that scarred his reputation for winning with integrity. 2012 Feb 6, In Pennsylvania Democrat state Rep. Bill DeWeese (61) was convicted of conspiracy, conflict of interest and theft in a investigation into the use of taxpayer resources for political purposes. 11 other Democrats and 9 Republicans have already been convicted or pleaded guilty in the (SFC, 2/7/12, p.A9) 2012 Feb 14, Hackers claimed to have broken into Combined Systems Inc.'s website and stolen personal information belonging to clients and employees of the Jamestown, Pennsylvania-based firm, whose tear gas has been used against Egyptian demonstrators. They accused the company of being run by war profiteers who sell "mad chemical weapons to militaries and cop shops around the world." 2012 Mar 8, In Pennsylvania John Shick (30) opened fire at a psychiatric clinic at the Univ. of Pittsburgh killing Michael Schaab (25) and wounding 6 others before (SFC, 3/9/12, p.A6)(SFC, 3/10/12, p.A5) 2012 Mar 29, In Pennsylvania the bodies of Charles (81) and Adrienne Snelling (81) were found in their home in Trexlertown. Charles killed his wife and himself. He had written in the NY Times last December about his love for his (SFC, 3/31/12, p.A5) 2012 Mar 30, The US government agreed with Illinois, Michigan, Minnesota, New York and Pennsylvania to cut red tape and speed up consideration for wind farms in the (SFC, 3/31/12, p.A5) 2012 Apr 9, In Pennsylvania 2 firefighters were killed while battling a massive blaze in an abandoned warehouse in Philadelphia. (SFC, 4/10/12, p.A7) 2012 Apr 10, Rick Santorum suspended his campaign during a press conference in Pennsylvania, his home state. (SFC, 4/11/12, p.A1) 2012 Jun 19, In Pennsylvania Patricia Smith (58), the former controller of the Baierl Automotives auto dealership, was sentenced to 78 months in prison and pay restitution of $10,349,569.14 for embezzling from her former boss in a stunning case of a trusted employee looting the business then squandering the cash on luxuries. 2012 Jun 22, In Pennsylvania Jerry Sandusky (68), former defensive coach at Penn State, was convicted of sexually assaulting 10 boys over 15 years. (SFC, 6/23/12, p.A4) 2012 Jul 18, The city of Scranton, Pa., restored the salaries of its 400 civil servants. Earlier this month Mayor Chris Doherty had slashed all municipal employees’ salaries to the federal minimum wage because the city did not have funds to pay their wages. (Econ, 7/21/12, p.26) 2012 Jul 23, The US NCAA imposed penalties on Penn State and its football program related to the cover-up of pedophile charges against former defensive coach Jerry Sandusky. The penalties included $60 million and the abdicating of all wins since 1998. (SFC, 7/25/12, p.A10) 2012 Jul 27, In Pennsylvania Kevin Cleeves (35) confronted his estranged wife about custody arrangements for their daughter and shot the woman to death and killed her boyfriend and his mother in Quincy Township. He then fled with his daughter (4) before the two were found the next day about 250 miles away in Ohio. 2012 Aug 18, Philadelphia police Officer Moses Walker (40) was shot to death, while out of uniform, by a suspected street robber near his station. (SSFC, 8/19/12, p.A12) 2012 Sep 23, It was reported that Germany has launched a war crimes investigation against Johann Breyer, (b.1925) a Philadelphia man it accuses of serving as an SS guard at the Auschwitz death camp. 2012 Oct 2, Pennsylvania's divisive voter identification requirement became the latest of its kind to get pushback from the courts ahead of Election Day, delivering a hard-fought victory to Democrats who said it was a ploy to defeat President Barack Obama and other opponents who said it would prevent the elderly and minorities from voting. 2012 Oct 11, A batch of newly designed $100 bills, that aren't going into circulation until next year, was stolen from a plane that arrived at Philadelphia International Airport around 10:25 a.m. from Dallas. The Benjamins are easy to spot. The new bills have sophisticated elements to thwart counterfeiters, like a disappearing Liberty Bell in an orange inkwell and a bright blue security ribbon. 2012 Oct 14, Arlen Specter (b.1930), Pennsylvania's longest-serving US senator and prominent Republican moderate in Congress, died at his home in Philadelphia. (AP, 10/15/12)(SFC, 10/15/12, p.A4) 2012 Nov 7, A wintry storm dropped snow and rain on the Northeast, bringing dangerous winds and knocking out power in a region where hundreds of thousands were still in the dark after Superstorm Sandy. A mix of rain and snow fell on parts of New York, New Jersey, Connecticut, Pennsylvania and Massachusetts, causing airport delays. 2012 Dec 21, In Pennsylvania Jeffrey Lee Michael of Geeseytown (44) fatally shot a woman decorating for a children's Christmas party at a tiny church hall and killed two men elsewhere in a rural township before he was shot dead in a gunfight with state troopers. (AP, 12/22/12)(AP, 12/22/12) 2013 Jan 26, Pennsylvania police said Stephen Baker (62), a Franciscan brother, was found dead of a self-inflicted knife wound at the St. Bernardine monastery. Baker was named in recent settlements involving 11 men who alleged that he sexually abused them 3 decades ago in Ohio. More people soon came forward with abuse claims in Pennsylvania, where Baker had taught and coached. (SSFC, 1/27/13, p.A6)(SFC, 2/25/13, p.A4) 2013 Jan 31, In Philadelphia, Pennsylvania, a federal indictment charged 9 judges with fixing traffic tickets for friends, relatives, business associates and (SFC, 2/1/13, p.A7) 2013 Feb 21, Suspended Pennsylvania Supreme Court Justice Joan Orie Melvin along with her aide and sister, Janine Orie, were convicted on campaign corruption charges. They could join a third sister — former state Sen. Jane Orie — in state prison. 2013 Feb 25, In Pennsylvania an inmate assaulted and killed a guard with a homemade weapon at the Canaan federal penitentiary. (SFC, 2/27/13, p.A4) 2013 Mar 16, In Pennsylvania a tour bus carrying a women’s lacrosse team from Seton Hill Univ. crashed killing a pregnant coach and the driver. (SSFC, 3/17/13, p.A9) 2013 Apr 20, In Pennsylvania Dr. Autumn Klein (41) died after falling ill at home. A coroner later found cyanide in her system. On July 25 her husband, Univ. of Penn. researcher Dr. Robert Ferrante, was arrested on charges that he had poisoned her. On Nov 7, 2014, Ferrante (66) was convicted of 1st degree murder. On Feb 4, 2015, Ferrante was sentenced to mandatory life in prison. (SFC, 7/26/13, p.A7)(SFC, 11/8/14, p.A5)(SFC, 2013 May 6, The SEC issued a long report on the financial misdeeds of Harrisburg, Pa. The state capital has been bankrupt since 2011. (Econ, 5/11/13, p.80) 2013 May 12, In Pennsylvania a late night house fire in Pottsville killed 4 children, their father and an aunt as the mother did laundry at a friend’s house across the (SFC, 5/14/13, p.A5) 2013 May 13, Pennsylvania Dr. Kermit Gosnell (72) was convicted of first-degree murder in the deaths of 3 babies and involuntary manslaughter in the overdose death of an abortion patient. The next day Gosnell gave up his right to appeal in exchange for a life sentence. (SFC, 5/14/13, p.A4)(SFC, 5/15/13, p.A6) 2013 May 18, In Pennsylvania Richard DeCoatsworth (27), a former Philadelphia police officer, was arraigned on charges including rape, involuntary deviate sexual intercourse, trafficking of persons, false imprisonment and aggravated assault. His bail was set at $60 million. He had hailed as a hero after he was shot in the face during a traffic stop in September 2007 but still managed to chase after his attacker, who was later sentenced to 36 to 72 years in prison. 2013 May 22, In Pennsylvania Herbert (44) and Catherine Schaible (43), advocates of faith healing, were arrested following the death of their 9th child, 8 months old, in April. Herbert said “Medicine is against our religious beliefs." They had received a 10 year probation in Feb, 2011, following the death of their son, Kent. (SFC, 5/25/13, p.A7) 2013 Jun 5, In Pennsylvania a four-story building being demolished collapsed on the edge of downtown Philadelphia. 6 people were killed and at least 14 others injured. On June 7 police said Sean Benschop (42), a heavy equipment operator with a lengthy rap sheet, was high on marijuana when the building collapsed. Benschop turned himself in on June 8. On Nov 25 contractor Griffin Campbell was charged with 6 counts of third-degree murder. In 2014 a judge upgraded charges against Benschop to 3rd degree murder. On Oct 9, 2015, Campbell was convicted of involuntary manslaughter. On Jan 8, 2016, Campbell was sentenced to 15-30 years in prison. Benschop was sentenced to 7.5-15 years in prison. (AP, 6/5/13)(SFC, 6/6/13, p.A8)(AP, 6/8/13)(SSFC, 6/9/13, p.A12)(SFC, 11/26/13, p.A8)(SFC, 2/19/14, p.A5)(SFC, 10/20/15, p.A7)(SFC, 1/9/16, p.A5) 2013 Jul 15, In Philadelphia Michael Scripps (36), a descendent of the founder of the Detroit News, was sentenced to 9 years in priuson for stealing $3.6 million from his mother and disabled uncle. (SFC, 7/16/13, p.A4) 2013 Jul 24, In Pennsylvania at least 5 same-sex couples obtained marriage licenses in Montgomery County. It was up to Republican Gov. Tom Corbett or other state officials to challenge the actions. A 1996 state law defined marriage as a civil contract in which a man and a woman take each other as husband and wife. (SFC, 7/25/13, p.A11) 2013 Jul 28, William Scranton (b.1917), former US ambassador to the UN (1976-1977) and the 38th governor of Pennsylvania (1964-1967), died in southern, California. (SFC, 8/2/13, p.D7) 2013 Aug 5, In Pennsylvania Rockne Newell (59) blasted shots through a wall of the state municiple building in Ross Township and then barged into a meeting room and continued firing. 3 people were killed before he was tackled by a local official and shot with his own gun. Newell was taken into police custody. (SFC, 8/6/13, p.A6) 2013 Oct 19, In Pennsylvania an SUV crossed a center line and ran into two motocycles. 4 people on the motorcycles and one person in the SUV were killed in Franklin (SFC, 10/21/13, p.A3) 2013 Nov 11, In Pennsylvania Troy LaFerrara was stabbed to death. His body was found the next day in an alley in Sunbury. He had responded to an online ad for companionship in exchange for money and was stabbed to death a day earlier. On Dec 6 Elytte Barbour (22) and wife Miranda (18) were arrested. The couple, married for three weeks, said they had wanted to kill someone together. On Sep 18, 2014, the Barbours were sentenced to life in prison. (SSFC, 12/8/13, p.A12)(SFC, 9/19/14, p.A6) 2014 Jan 2, In Pennsylvania Monsignor William Lynn left prison after 18 months behind bars. He was the first US church official ever charged for hiding complaints that priests were molesting children. (SFC, 1/3/14, p.A6) 2014 Jan 6, In Pennsylvania Colleen LaRose (50), aka “Jihad Jane," was sentenced to ten years in prison for plotting to kill a Swedish artist. She had pleaded guilty and helped in the indictment of two others. (SFC, 1/7/14, p.A6) 2014 Jan 17, A Pennsylvania judge struck down a state requirement that voters show photo identification at the polls. (SFC, 1/18/14, p.A6) 2014 Jan 17, In Pennsylvania a school shooting wounded two students at the Delaware Valley Charter High School. Raisheem Rochwell (17) was charged the next day as an (SSFC, 1/19/14, p.A8) 2014 Feb 6, In Pennsylvania a winter storm left some 849,000 people without power for a 2nd day. The 2nd winter storm this week in the mid-Atlantic had dumped more than a foot of snow in some places. (SFC, 2/7/14, p.A8) 2014 Feb 16, In Pennsylvania the FBI said it was in contact with Sunbury police regarding Miranda Barbour (19) who says she wants to plead guilty to the killing Troy LaFerrara last November. She said she has also killed at least 22 people across the country over the last six years as part of her involvement in a satanic cult. (SFC, 2/17/14, p.A6) 2014 Feb 19, In Pennsylvania Herbert and Catherine Schaible were sentenced to 3½ to seven years in prison in the death of a 2nd child who never saw a doctor despite being stricken with pneumonia. (SFC, 2/20/14, p.A6) 2014 Apr 9, In Pennsylvania Alex Hribal (16) stabbed and slashed 21 fellow students and a security guard at the Franklin Regional High School in Murrysville. (SFC, 4/10/14, p.A7) 2014 May 20, A US federal judge overturned Pennsylvania’s ban on same-sex marriage. (SFC, 5/21/14, p.A8) 2014 May 31, Lewis Katz (72), a co-owner of the Philadelphia Inquirer, was among 7 people killed in the crash of his small plane in Bedford, Mass. (AP, 6/1/14)(SFC, 6/3/14, p.A6) 2014 Jun 14, Pres. Obama intervened in a commuter rail strike in Philadelphia, granting Gov. Tom Corbett’s request to create an emergency board to mediate a (SSFC, 6/15/14, p.A10) 2014 Jun 15, In Pennsylvania Jeff Hooten (47), the pilot of a hot air balloon, fell from the basket while trying to land near Philadelphia and died after becoming trapped under it. (SFC, 6/17/14, p.A7) 2014 Jun 17, US authorities in Philadelphia arrested Johann Breyer (89) after a German warrant charged him with 158 counts of complicity in the killing of Jews while he was a guard at Auschwitz in 1944. Breyer died on July 22, hours before a ruling on his extradition to Germany. (SFC, 6/19/14, p.A9)(SFC, 7/24/14, p.A8) 2014 Jul 5, In Philadelphia, Pa., an infant and three children (4) died as a fire engulfed at least 10 houses. (SSFC, 7/6/14, p.A11) 2014 Jul 8, US East Coast states experienced severe storms and high winds. 4 people were killed in New York and one in Maryland. CNN reported nearly 500,000 homes and businesses without power, mostly in Pennsylvania and New 2014 Jul 25, In Philadelphia two men forced a woman into the back seat of her vehicle and drove off. They later lost control and plowed into a group of people near a fruit stand killing 3 children. Both men fled the scene. (SFC, 7/26/14, p.A7) 2014 Jul 30, US government agents arrested six Philadelphia narcotics officers on charges they robbed and in some cases kidnapped drug dealers, including dangling one over an 18th story balcony to force him to give up a computer password. The men were accused of stealing hundreds of thousands of dollars in cash and items including a Rolex watch and a designer suit. In one instance, they are accused of seizing cocaine and reselling it on the street. 2014 Aug 27, In in Stratford, Pa., Raymond Wychowanec (63) shot and killed his hospitalized wife (62) and then tried to kill himself, prompting investigators to search their New Jersey home, where their son (35) was found fatally 2014 Sep 12, In Pennsylvania a deadly ambush at a state police barracks in Blooming Grove left Cpl. Bryon Dickinson dead and trooper Alex Douglass critically wounded. Police soon identifed Eric Frein (31) as the prime suspect. (SFC, 9/15/14, p.A6)(SFC, 9/18/14, p.A7) 2014 Oct 21, In Pennsylvania 84 former students who were sexually molested by Franciscan Brother Stephen Baker at a Catholic high school in Altoona settled their legal claims for $8 million. Baker worked at the school as an athletic trainer from 1992 to 2001. (SFC, 10/22/14, p.A7) 2014 Oct 30, In Pennsylvania Eric Frein (31) was captured after a seven-week manhunt for killing a state trooper. US Marshals found Frein in an abandoned airplane hangar in Tannersville with his weapons inside. 2014 Oct 31, It was reported that a Pennsylvania coroner is auctioning off some 100 guns used in suicides and accidental deaths due to a state law requiring local governments to sell off unclaimed property. (SFC, 10/31/14, p.A10) 2014 Nov 4, Tom Wolf was elected governor of Pennsylvania with 54.9% of the vote. 2014 Dec 9, Philadelphia firefighter Joyce Craig Lewis died after becoming trapped in the basement of a burning home. She was the first female member of the city’s fire department to die in the line of duty. (SFC, 12/10/14, p.A8) 2014 Dec 15, In Pennsylvania Bradley William Stone (35), an Iraqi war veteran, shot dead 5 people at three locations outside Philadelphia and remained at large. Stone had recently been in court fighting his ex-wife over custody of their two children. Stone was found dead the next day in woods near (AFP, 12/15/14)(SFC, 12/16/14, p.A9)(SFC, 2014 Dec 22, Pennsylvania's Department of Environmental Protection (DEP) said it imposed a $999,900 fine on US oil and natural gas company Vantage Energy Inc, one of the largest given to a driller by DEP this year, for several environmental regulations violations. 2014 The US federal government confirmed the arrival of lanternflies, a planthopper native to southeast Asia, in southeastern Pennsylvania. By 2019 the insects threatened $18 billion worth of the state's agriculture and had expanded into Delaware, New Jersey and Virginia. (SFC, 9/27/19, p.A10) 2015 Feb 4, In Pennsylvania Ryan Mangan (16) of Jeanette was found sitting in a chair with a single gunshot wound to his face. Police soon arrested Maxwell Morton (16) after the mother of a third boy called to say that her son had received a selfie that showed the victim shot in the face. (SFC, 2/10/15, p.A4) 2015 Jan 7, In Pennsylvania a 2 people died in an 18-vehicle crash on I-80 after a snow squall left drivers with little visibility. (SFC, 1/9/15, p.A6) 2015 Jan 20, Tom Wolf (b.1948) began serving as the 47th governor of Pennsylvania. 2015 Feb 20, Western Pennsylvania recorded record temperatures in New Castle (-18), in Butler (-15) and in Pittsburgh (-6). (SFC, 2/21/15, p.A6) 2015 Mar 5, In Philadelphia, Pa., Officer Robert Wilson III (30) was gunned down during a robbery at a video game store where he had gone to buy a present for his 9-year-old son. The next day two brothers, Ramone Williams (24) and Carlton Hipps (29) were charged with murder, attempted murder, robbery and other offenses. (AP, 3/6/15)(AP, 3/15/15) 2015 May 4, A report on drinking water in Bradford County, Pa., revealed traces of a compound commonly found in Marcellus Shale drilling fluids. (SFC, 5/5/15, p.A6) 2015 Mar 24, In Pennsylvania Hummelstown police Officer Lisa J. Mearkle (36) was charged with criminal homicide after investigators concluded she shot an unarmed motorist in the back as he lay facedown after a traffic stop over an expired inspection sticker. (AP, 3/24/15)(SFC, 3/25/15, p.A8) 2015 May 12, In Pennsylvania an Amtrak derailment late today killed 8 people. Brandon Bostian (32) was at the helm of the train when it derailed while traveling at 106 miles per hour, more than double the limit. (AFP, 5/13/15)(SFC, 5/15/15, p.A7) 2015 May 21, In Pennsylvania Xi Xiaoxing (47), the chairman of Temple University's physics department, appeared in U.S. District Court on four counts of wire fraud. Federal prosecutors said he had sought prestigious appointments in China in exchange for providing data on electronics technology invented by a US firm and offered to make the country a leader in the field of superconductivity. 2015 Jun 3, In Pennsylvania two semi-trucks crashed with a charter bus killing Italian tourists Marco Fornasetti and Rino Guerra, along with NYC bus driver Alfredo Telemaco. In 2017 truck driver Franklin Wyatt (57) was arraigned on 34 charges, including three counts of involuntary manslaughter. 2015 Jun 24, In the northeast US a fast moving storm hit Connecticut, New Jersey and eastern Pennsylvania overnight leaving two people dead and nearly 400,000 customers without power. (SFC, 6/25/15, p.A6) 2015 Jul 6, In Philadelphia a 2005 deposition testimony by former TV star Bill Cosby was unsealed. In it Cosby admitted that he had obtained quaaludes to give young women before sex. More than two dozen women have accused Cosby of sexual misconduct dating back more than four decades. (SFC, 7/8/15, p.A8) 2015 Jul 9, In Pennsylvania Gary Machinshok (29) of Wilkes-Barre was sentenced to up to 27 years in prison for raping his wife's daughter (15) in an effort to conceive a baby the couple could raise. Machinshok testified against his wife, who was sentenced in April to 15 to 30 years in prison. She pleaded guilty in January to charges including rape, assault, endangering the welfare of a child and conspiracy. 2015 Jul 29, In Pennsylvania US Rep. Chaka Fattah (58) was indicted with four associates in a racketeering case stemming from the alleged misappropriation of hundreds of thousands of dollars after a failed 2007 run for mayor (SFC, 7/30/15, p.A6) 2015 Jul, Surgeons at the Children’s Hospital of Philadelphia completed a double-hand transplant for Zion Harvey (8) of Maryland, who had lost his hands and feet to a serious infection. (SFC, 7/30/15, p.A6) 2015 Aug 1, HitchBOT, the adorable hitch-hiking robot cobbled together from household odds-and-ends, prematurely ended its summer travels across America, after being destroyed by vandals and abandoned on the side of a road in Philadelphia. The little talking automaton had hitchhiked unscathed last summer across thousands of miles in Canada, and had traversed parts of Europe as well without so much as a scratch. Canadian creators Frauke Zeller and David Smith considered (AFP, 8/3/15)(SFC, 8/3/15, p.A4)(SFC, 8/4/15, 2015 Aug 6, Pennsylvania’s Attorney Gen’l. Kathleen Kane was charged with leaking secret grand jury information and lying about her actions under oath. (SFC, 8/7/15, p.A5) 2015 Aug 13, A Pennsylvania judge, citing new DNA evidence, vacated the murder conviction of Lewis Fogle (63), who has been in prison for 34 years in the shooting death of a girl (15). (SFC, 8/14/15, p.A6) 2015 Sep 26, Pope Francis traveled to Philadelphia to promote the issue of religious freedom on the penultimate day of his first visit to the United States. 2015 Sep 27, In Philadelphia, Pa., Pope Francis met with victims of child sexual abuse on the final day of his US visit and promised to hold accountable those responsible for the scandal in the church. 2015 Oct 13, In Pennsylvania Army veteran James Vernon (75) fended off a knife attack by Dustin Brown (19), a mentally ill man, at the Morton Public Library in Pittsburgh. Vernon suffered two slashed arteries and a damaged tendon in a finger. In 2017 he was one of 18 people honored with a Carnegie medal for heroism. (SFC, 9/20/17 p.A6) 2015 Nov 17, Pennsylvania-based Education Management Corp. agreed to pay $96 million to settle claims it illegally paid recruiters based on the number of students they enrolled. Five states had participated in four lawsuits. (SFC, 11/18/15, p.A12) 2015 Dec 7, Lawyers hired by the Turkish government filed a civil suit against cleric Fethullah Gulen, a political enemy of President Tayyip Erdogan, in a US court alleging human rights abuses. Gulen has lived in Pennsylvania since 2015 Dec 16, Total Trib Media said it is closing the Valley Independent in Monessen and the Daily News in McKeesport, western Pennsylvania on Dec 31, putting 87 employees out of work. (SFC, 12/17/15, p.A12) 2016 Jan 7, In Philadelphia policeman Jesse Hartnett (33) was shot three times in his left arm as he sat in his patrol car late today. Edward Archer (30), claiming allegiance to the Islamic State extremist group, opened fire multiple times at point-blank range with a stolen police gun before he was arrested. 2016 Jan 12, In Pennsylvania philanthropist H.F. Lenfest, owner of the Philadelphia Inquirer, the Philadelphia Daily News and Philly.com, said he has turned over the Philadelphia Media Network to the newly formed nonprofit Institute for Journalism in New Media in an effort to develop a new business model. He also donated $20 million to endow the enterprise. (SFC, 1/13/16, p.C6) 2016 Feb 13, A dangerous cold snap bringing life-threatening cold was settling in across the northeastern United States. A snow squall triggered a pileup of dozens of vehicles on a Pennsylvania highway that left several 2016 Mar 9, In Pennsylvania an ambush-style shooting at a backyard barbecue in the Pittsburgh suburb of Wilkinsburg killed 5 people and an 8-month old fetus. Two gunmen working as a team remained on the run. (AFP, 3/10/16)(SFC, 3/10/16, p.A7) 2016 Mar 12, In Pennsylvania police officers in Chester engaged in a shootout that left one suspect dead after trying to stop a vehicle. (SFC, 3/14/16, p.A5) 2016 Mar 15, A 2nd Pennsylvania Supreme Court justice, Michael Eakins, quit the bench over a widening scandal over raunchy and otherwise offensive emails that he and others exchanged with friends and lawyers. (SFC, 3/16/16, p.A6) 2016 Mar 15, In Pennsylvania three leaders of a Franciscan religious order were charged with allowing a friar who was a known sexual predator to take on jobs that enabled him to molest more than 100 children. (SFC, 3/16/16, p.A6) 2016 Mar 20, In Pennsylvania retired state trooper Clarence Briggs killed turnpike toll collector Danny Crouse and security guard Ronald Heist in a holdup attempt in Fort Littleton. Biggs was shot dead by state troopers while trying to escape. Briggs had filed for banktuptcy in 2015 with debts of (SFC, 3/21/16, p.A6)(SFC, 3/22/16, p.A5) 2016 Apr 3, Amtrak Train 89 struck a piece of heavy equipment on the tracks outside Philadelphia, causing the train's lead engine to derail and killing two Amtrak workers. 2016 Apr 17, Pennsylvania Gov. Tom Wolf signed a bill legalizing a comprehensive medical marijuana program, making his state the 24th to do so. (SFC, 4/18/16, p.A7) 2016 Apr 17, In Pennsylvania a suspect surrendered to police following a short standoff at a Philadelphia home where 3 people were found killed by shotgun blasts to the head. (SFC, 4/18/16, p.A7) 2016 May 6, Federal authorities in Pittsburgh said two men have been charged by authorities in Belarus with receiving $1.35 million stolen in a phishing scheme from the bank account of a Pennsylvania oil and gas drilling company. Aleskey Yaroshevich (34) and Egor Pavlenko (41) reportedly received a $1.35 million transfer made in September 2012. Both men were in custody in Minsk. 2016 May 25, In Pennsylvania the Swiss-made Solar Impulse 2 landed in Allentown 17 hours after taking off from Dayton in the latest leg of its journey around the (SFC, 5/26/16, p.A6) 2016 Jun 12, In San Jose, Ca., the Pittsburgh Penguins won the Stanley Cup after Game 6 of the NHL hockey finals against the San Jose Sharks, seven years to the day after last holding the Cup. 2016 Jun 16, Philadelphia became the first major US city to approve a soda tax. The City Council gave final approval to a 1.5 cent-per-ounce tax on sugary and diet beverages with collections to begin next Jan 1. (SFC, 6/17/16, p.A15) 2016 Jul 8, In Pennsylvania Grace Packer (14), the adopted daughter of Sara Packer, was raped and smothered to death in a “rape-murder fantasy" shared by the mother and her boyfriend Jacob Sullivan. The couple dismembered the body in October and it was found by two hunters in Luzerne County on Oct 31. On Jan 6 Sullivan began confessing to the murder. (SFC, 1/9/17, p.A12) 2016 Jul 24, Democratic national leader Debbie Wasserman, D.-Fla., announced that she will step down at the end of the convention week following leaked internal party e-mails. (SFC, 7/25/16, p.A4) 2016 Jul 25, In Philadelphia, Penn., the Democratic National Convention got off to a rocky start Monday, with a major internal row over leaked emails playing havoc with nominee Hillary Clinton's bid to present a united front against 2016 Jul 26, In Pennsylvania Humberto Martinez (32), a man with a lengthy criminal history, died following a scuffle with police officers. A year later his family sued Pittsburg and its police department for wrongful death. (SFC, 7/27/17, p.D2) 2016 Jul 27, In Philadelphia President Barack Obama implored Americans to help Hillary Clinton beat Donald Trump, warning the 2016 race was not just about politics, but the nature of US democracy. 2016 Jul 28, At the Democratic convention in Philadelphia, Pa., Hillary Clinton became the first woman to accept a major party’s nomination for president. (SFC, 7/29/16, p.A1) 2016 Aug 15, Pennsylvania’s Attorney Gen’l. Kathleen Kane was convicted on nine charges including perjury and conspiracy for illegally leaking documents from a grand jury proceeding. She resigned the next day. (Econ, 8/20/16, p.25) 2016 Sep 25, American golfer Arnold Palmer (87) died in Pittsburgh. Palmer first played the British Open in 1960, finishing runner-up in an appearance that invigorated a tournament which Americans had been ignoring for years. Palmer won the British Open, golf's oldest major, in 1961 and (AP, 9/26/16)(Econ, 10/8/16, p.82) 2016 Nov 8, In the US presidential election Michigan, Pennsylvania and Wisconsin all swung for Donald Trump with margins of one percent or less. Wisconsin’s voter ID law impacted an unknown number of eligible voters as Trump defeated Clinton by roughly 22,000 votes. (Econ, 11/19/16, p.25)(SFC, 5/9/17, p.A4) 2016 Nov 9, From New York to Los Angeles thousands of people in around 10 cities rallied late today against president-elect Donald Trump. Protesters burned a giant orange-haired head of Trump in effigy, lit fires in the streets and blocked traffic as rage over the billionaire's election victory spilled onto the streets of Oakland, Ca., Chicago, Boston, Philadelphia, Portland and Washington DC. 2016 Nov 16, Journalist and author Peter Binzen (1922) died in Pennsylvania. His books included “Whitetown, USA" (1970). (SFC, 11/24/16, p.D2) 2016 Nov 24, It was reported that the former Green Party presidential candidate Jill Stein has raised the necessary $1.1 million to request a vote recount in Wisconsin. Donald Trump also won by a slim margin in Pennsylvania, where a recount filing fee costs $500,000, due on November 28. The filing fee in Michigan, where Trump has a razor-thin lead in unofficial results so far, is $600,000 due by November 30. 2016 Nov 24, In Pennsylvania Demetrius Coleman (22) of Pittsburgh fled police and crashed into a car that burst into flames killing two adults and a child. (SFC, 11/26/16, p.A3) 2016 Dec 30, Pennsylvania state Trooper Landon Weaver (23) was shot and killed while responding to a domestic complaint in Huntingdon County. Jason Robison (32) was arrested the next day at a mobile home in the area. (SSFC, 1/1/17, p.A7) 2017 Jan 31, US federal energy regulators approved construction of Energy Transfer Partners LP's Rover natural gas pipeline from Pennsylvania to Ontario. 2017 Jan 31, In Pennsylvania Daniel Dimitri (50) was killed in Philadelphia by a speeding police officer. Adam Soto was soon fired and in 2019 he was ordered to serve three to twelve months in county jail for killing Dimitri while drag racing with another officer. (SSFC, 1/13/19, p.A8) 2017 Feb 2, In Pennsylvania the Punxsutawney Phil groundhog saw his shadow and predicted six more weeks of winter. (SFC, 2/3/17, p.A6) 2017 Feb 4, Penn State student Timothy Piazza (19) died two days after falling several times with toxic levels of alcohol following a Feb 2 Beta Theta Pi fraternity pledge ceremony. Friends failed to summon immediate help. 18 fraternity members faced criminal charges. On Sep 1, 2017, a judge threw out involuntary manslaughter charges and felony assault counts and ordered 12 fraternity members to stand trial on lesser counts. Piazza had been given at least 18 drinks in less than 90 minutes. In 2019 three former Penn. State fraternity members were issued minimum jail sentences of one to three months. (SFC, 5/6/17, p.A6)(SFC, 9/2/17, p.A9)(SFC, 11/14/17, p.A7)(SFC, 4/4/19, p.A6) 2017 Feb 26, In Philadelphia a visitor to the Jewish Mount Carmel Cemetery discovered more than 100 headstones vandalized. This came less than a week after a Jewish cemetery in suburban St. Louis reported more than 150 headstones (SFC, 2/27/17, p.A4) 2017 Mar 13, Two former Penn State administrators pleaded guilty to mishandling child-sex allegations against Jerry Sandusky, more than five years after the scandal rocked the university and led to the downfall of football coach Joe Paterno. (SFC, 3/14/17, p.A7) 2017 Mar 14, Winter Storm Stella dumped snow and sleet across the northeastern United States, forcing airlines to ground flights and schools to cancel classes. Airlines canceled about 5,700 flights across the United States. Airports in New York, Boston, Baltimore, Washington and Philadelphia were hit the hardest. (AP, 3/14/17)(AFP, 3/14/17) 2017 Mar 24, Former Penn State Pres. Graham Spanier (68) was convicted of hushing up complaints in 2001 of child sex abuse by assistant football coach Jerry Sandusky. (SFC, 3/25/17, p.A5) 2017 Mar, A Pennsylvania judge ruled that Allentown-based, long-term care insurer Penn Treaty American Corp. was insolvent. This left health insurers across the country on the hook for the company’s losses. Analysts estimated the company’s long-term liabilities near $4 billion, but assets at only about $700 million. (SFC, 8/14/17, p.D1) 2017 Apr 14, Henry Hillman (b.1918), Pittsburgh-based billionaire, died. He had steered his family’s coal and coke fortune into real estate, venture capital and private equity. In 1972 his $4 million investment provided half the startup money for the Menlo Park, Ca., Kleiner Perkins venture (SSFC, 4/16/17, p.C10) 2017 Apr 17, In Pennsylvania Cuban national Yoandy Perez Llanes pleaded guilty to his role in an international conspiracy to file 900 phony federal tax returns seeking $2.2 million in refunds by using employee information stolen from the University of Pittsburgh Medical Center. Sentencing was set for August 18. 2017 Apr 18, Ohio murder suspect Steve Stephens (37) shot himself in the head following a police chase in Pennsylvania. (SFC, 4/19/17, p.A8) 2017 Apr 19, In Pennsylvania the new Museum of the American Revolution opened in Philadelphia. 2017 Jun 6, In Pennsylvania Lee Donald Kaplan (52) was convicted of sexually assaulting six girls in the same family and fathering two children by one of them. Authorities alleged that the girls’ parents had “gifted" their oldest daughter to Kaplan because he helped the family out of financial ruin. On July 19 a judge sentenced Daniel Stoltzfus (44) and his wife Savilla (43) up to seven years in prison each for gifting their oldest daughter to Kaplan. (SFC, 6/7/17, p.A6)(SFC, 7/27/17, p.A6) 2017 Jun 15, James McCord Jr., former CIA agent and head of the burglers in the 1972 Watergate scandal, died at his home in Pennsylvania. (SSFC, 4/21/19, p.C9) 2017 Jun 17, A Pennsylvania judge declared a mistrial as jurors deadlocked on charges that Bill Cosby had drugged and molested a woman more than a decade ago. Prosecutors said they would seek a 2nd trial. (SSFC, 6/18/17, p.A8) 2017 Jun 20, GE Transportation said it has signed a $575 million deal with Egypt's national railway system to provide 100 locomotives. Most of the company's international locomotives are built in Erie, Pennsylvania. 2017 Jun 29, In Pennsylvania Seth Williams (50), the District Attorney of Philadelphia, pleaded guilty to a corruption charge and resigned from office. He had been charged with 29 counts of bribery, extortion and fraud. (SFC, 6/30/17, p.A6) 2017 Jun 28, In Pennsylvania Bianca Roberson (18), a recent high school graduate, was shot in the head during a road rage confrontation in West Goshen Township. David Desper (28), who fled the scene, turned himself in on July 2 and was charged with first and third degree murder. (SFC, 7/3/17, p.A4) 2017 Jul 7, In Pennsylvania three young men went missing in suburban Philadelphia. A 4th had gone missing two days earlier. Links between the men were being (SFC, 7/11/17, p.A6) 2017 Jul 13, In Pennsylvania drug dealer Cosmo DiNardo (20) confessed to killing four men separately after selling them marijuana and then burning their bodies on his family’s farm. A cousin of DiNardo was also charged the next day, but said DiNardo had shot all the victims. (SFC, 7/14/17, p.A6)(SFC, 7/15/17, p.A5) 2017 Jul 25, In Pennsylvania the 3rd U.S. Circuit Court of Appeals upheld the conviction of Joseph Maurizio (71), accused of sexually abusing orphans during missionary trips to Honduras, and denied his request for a new trial. The suspended priest has maintained his innocence. Maurizio was incarcerated at a low-security federal prison in Ohio with a projected release date of April 2029. 2017 Aug 2, In Pennsylvania 32 CSX freight cars derailed in Hyndman and caused a propane fire that burned itself out by August 4. Smaller sulfur fires continued to (SFC, 8/5/17, p.A6) 2017 Aug 31, In Pennsylvania Temple Univ. student Jenna Burleigh (22) was last seen on surveillance tape leaving a bar in Philadelphia with Joshua Hupperterz (29). Her body was found Sep 2 on property belonging to the man’s grandmother. On Sep 3 Hupperterz was charged with murder. (SFC, 9/5/17, p.A4) 2017 Sep 19, Oil and gas pipeline company Energy Transfer Partners LP said it has received approval from US energy regulators to resume drilling along its $4.2 billion Rover pipeline project. The Rover project from Pennsylvania to Ontario is the biggest gas pipeline under construction in the 2017 Oct 4, Republican congressman Tim Murphy of Pennsylvania announced that he will not run for a 9th term, amid tawdry revelations of an extramarital affair in which the antiabortion lawmaker urged his mistress Shannon Edwards to get an abortion when he thought she was pregnant. (SFC, 10/5/17, p.A5) 2017 Oct 23, In Pennsylvania a law took effect that allows casino-style gambling on mobile phones and websites. It also put video gaming terminals in big truck stops. 2017 Nov 3, Philadelphia officials announced that they will move the statue of former Mayor and Police Commissioner Frank Rizzo from its location in the shadow of City Hall. Rizzo served as mayor form 1973-1980 and his critics argue that he led a corrupt police department that alienated (SFC, 11/4/17, p.A5) 2017 Nov 13, In Pennsylvania Yinyan Wang (25), a Chinese citizen, was arrested on visa and passport fraud charges. She had reportedly taken the GRE graduate school entry exam for other people. 2017 Nov 17, In Pennsylvania rookie police Officer Brian Shaw (25) died after being shot following a traffic stop that led him to chase someone on foot in New Kensington. On Nov. 21 suspect Rahmael Sal Holt (29) was arrested in Pittsburgh following a 4-day manhunt. (SSFC, 11/19/17, p.A8)(SFC, 11/20/17, p.A5)(SFC, 2017 Dec 15, A federal judge in Philadelphia ordered the Trump administration not to enforce new rules that could significantly reduce women’s access to free birth (SFC, 12/16/17, p.A6) 2018 Jan 8, In Pennsylvania the Pi Delta Psi national fraternity was banned from the state for ten years and ordered to pay a fine of more than $110,000 as it was sentenced for its role in the 2013 death of Baruch College freshman Chun Deng (19). Four former fraternity members were also sentenced from time served up to 24 months. (SFC, 1/9/18, p.A10) 2018 Jan 20, A New York Times online story reported that US Rep. Patrick Meehan of Pennsylvania used taxpayer money to settle a complaint that stemmed from his hostility toward a former aide who rejected his romantic overtures. (SFC, 1/22/18, p.A4) 2018 Jan 22, The Pennsylvania Supreme Court struck down the boundaries of the state’s 18 congressional districts, saying they violate the state constitution. Democratic voters had argued that the districts were gerrymandered to benefit Republicans. (SFC, 1/23/18, p.A6) 2018 Jan 28, In Pennsylvania four people were shot and killed at a carwash in Saltlick Township. Suspect Tim Smith, driven by apparent jealousy, was on life support with a possibly self-inflicted gunshot wound after the shooting. (SFC, 1/29/18, p.A5) 2018 Feb 4, Philadelphia Eagles fans celebrated their first NFL title since 1960 as the Eagles defeating the favored New England Patriots 41-33 in Super Bowl LII. Quarterback Nick Foles led a late-game comeback to cap a season that began as a backup and ended as Super Bowl 52 MVP. 2018 Feb 15, Pennsylvania’s Attorney General said seven guards have been charged with sexually abusing inmates at the Lackawanna County Prison in Scranton. (SFC, 2/17/18, p.A4) 2018 Feb 19, Pennsylvania’s high court issued a new congressional district map for the state’s 2018 elections. Republicans had held seats in bizzarely contorted (SFC, 2/20/18, p.A5) 2018 Mar 7, The second winter storm within a week crept into New York and surrounding states. New York’s three major airlines reported a total of 1,431 canceled flights, about 40 percent of their normally scheduled flights. The governors of New Jersey and Pennsylvania declared states of 2018 Mar 18, In Bermuda Mark Dombroski (19), a US student at Philadelphia's St. Joseph Univ., went missing early today in Hamilton. His body was found the next day. An autopsy later concluded that Dombroski had died from an apparent fall with no signs of foul play. (SFC, 3/20/18, p.A2)(SFC, 3/23/18, p.A2) 2018 Mar 23, In Pennsylvania Jonathan Foster (35) and his wife Grace (34), members of the Faith Tabernacle Congregation, were convicted of involuntary manslaughter in the 2016 death of their daughter (2). Prosecutors said they declined to seek medical care for the child on religious grounds. (SSFC, 3/25/18, p.A10) 2018 Mar 26, Pennsylvania environmental regulators issued another notice of violation to Energy Transfer Partners LP's Sunoco Mariner East 2 natural gas liquids pipeline for releasing drilling fluids into a wetland. 2018 Mar 27, In Pennsylvania Taiwanese exchange student An Tso Sun (18) was arrested for threatening to shoot up the Monsignor Bonner and Archbishop Prendergast High School, which he attended in Upper Darby. 2018 Apr 17, A Southwest Airlines Co. jet landed in Philadelphia after an engine blew up in mid air, killing a passenger in the first deadly US commercial airline accident in nine years. The engine explosion occurred about 20 minutes after the Dallas-bound Southwest Flight 1380 with 149 on board took off from New York's LaGuardia Airport. (Reuters, 4/18/18)(SFC, 4/17/18, p.A7) 2018 Apr 27, Philadelphia mob boss Joseph Merlino pleaded guilty to an illegal gambling charge as part of a deal allowing him to avoid a retrial in in a NYC (SFC, 4/28/18, p.A5) 2018 May 15, A violent spring storm left at least five people dead in the northeastern United States. The next morning more than 370,000 residents were without power in New York, New Jersey, Connecticut and Pennsylvania, down from more than 600,000. 2018 Jun 6, A US federal judge ruled that the Trump administration cannot cut off grants to Philadelphia over the way the city deals with immigrants in the (SFC, 6/7/18, p.A7) 2018 Jun 19, In Pennsylvania police Officer Michael Rosfeld (30) shot and killed Antwon Rose Jr. (17) in East Pittsburgh after stopping an unlicensed taxi that was said to match a vehicle wanted in a shooting in a nearby town. Zaijuan Hester, a passenger in the same car, later pleaded guilty for shooting a man in the abdomen. Protests soon followed after the unarmed black teenager was reportedly shot three times in the back. On June 27 Officer Rosfeld was charged with criminal homicide. On August 1 Rose's family filed a wrongful death suit against Rosfeld. On March 22, 2019, a jury acquitted former Officer Rosfeld. (SFC, 6/27/18, p.A5)(SFC, 6/28/18, p.A6)(SFC, 8/3/18, p.A6)(SFC, 3/20/19, p.A10)(SFC, 3/23/19, p.A5) 2018 Jul 18, Pennsylvania's highest court upheld Philadelphia's tax on soda and other sweetened (SFC, 7/18/18, p.A4) 2018 Jul 25, Rescuers pulled people from inundated cars on flooded streets near Baltimore as heavy rain soaked the US mid-Atlantic coast for a fifth day. Authorities closed highways and roads in parts of Maryland, Pennsylvania and Virginia because of flooding. 2018 Aug 14, Pennsylvania officials released a grand jury report that identified more than 300 "predator priests" who molested children in six dioceses since the (SFC, 8/15/18, p.A6)(SFC, 8/16/18, p.A4) 2018 Sep 10, Pennsylvania's state prisons resumed normal visits 12 days after officials imposed restrictions while they addressed a spate of illnesses linked to (SFC, 9/11/18, p.A5) 2018 Sep 18, Philadelphia announced an agreement to overhaul its civil forfeiture laws limiting what law enforcement officers can seize and what proceeds from the confiscated property can fund. (SFC, 9/19/18, p.A4) 2018 Sep 26, Comedian Bill Cosby (81) began serving his three to ten year sentence for sexual assault at he SCI Phoenix state prison in Collegeville, Pa. (SFC, 9/27/18, p.A6) 2018 Sep 29, In Pennsylvania a car exploded in Allentown leaving three men dead. Police called it a criminal incident. Jacob Schmoyer (26) was killed along with his son (2) and friend David Hillman (66). Police later said Schmoyer had sent letters indicating he used an explosive to kill himself, his son and friend. (SFC, 10/1/18, p.A4)(SFC, 10/5/18, p.A6) 2018 Oct 15, In Pennsylvania a charter bus crashed into trees near Scranton killing one person and injuring at least three others. (SFC, 10/16/18, p.A6) 2018 Oct 17, In Pennsylvania Rev. David Lee Poulson (65) of Oil City admitted that he sexually abused children and pleaded guilty to corruption of minors and child (SFC, 10/18/18, p.A9) 2018 Oct 24, The John D. and Catherine T. MacArthur Foundation announced thirteen winners of its Safety and Justice Challenge grants to cities and counties for implementing criminal justice reforms to reduce jail populations. Philadelphia's award of $4 million was the largest and followed a $3.5 million grant during the first awards in 2016. (SFC, 10/25/18, p.A8) 2018 Oct 27, In Pittsburgh, Pa., Robert Bowers (46) killed eight men and three women inside the Tree of Life Synagogue during worship services before a tactical police team shot and wounded him. Bowers told officers afterward that Jews were committing genocide and that he wanted them all to 2018 Nov 19, In Pennsylvania two men and two women were found fatally shot in a basement of a house being renovated in Philadelphia. (SFC, 11/20/18, p.A5) 2019 Jan 24, In Pennsylvania Jordan Witmen opened fire at a hotel bar in State College killing two people and wounding a woman. He then broke into a home and fatally shot another man before killing himself. (SFC, 1/26/19, p.A6) 2019 Jan 21, Harris Wofford (92), former Pennsylvania senator (1991-1995), died in Washington (https://en.wikipedia.org/wiki/Harris_Wofford)(SSFC, 1/27/19, p.C9) 2019 Feb 21, Moshe Journo (53), an Israeli man who allegedly had been on the run for 15 years after being accused of raping a teenage girl in Pennsylvania, was extradited back to the United States. 2019 Mar 18, Former Pennsylvania pediatrician Johnnie Barto was sentenced to at least 79 years in prison for the sexual assault of 31 children, most of them (SFC, 3/19/19, p.A8) 2019 Mar 20, Philadelphia health officials said 74 people have contracted mumps at Temple Univ. This included 15 confirmed and 59 probable cases. (SFC, 3/21/19, p.A6) 2019 Mar 26, An attorney said the Pennsylvania Roman Catholic Diocese of Erie has agreed to pay $2 million to a man who was sexually abused as a child by a priest who made him say confession after the assaults. Defrocked priest David Poulson was sentenced this year to 2½ to 14 years in prison after pleading guilty to the sexual assault of one boy and attempted sexual assault of another. 2019 Apr 9, Pittsburgh Mayor Bill Peduto signed legislation restricting military-style assault weapons and banning most uses of armor-piercing ammunition and high-capacity magazines, defying the state's prohibition on municipal gun regulation. (SFC, 4/10/19, p.A5) 2019 May 19, In Bethlehem, Pa., Martin Tower, the former world headquarters of Bethlehem Steel, was imploded to make way for a $200 million development project. (SFC, 5/20/19, p.A6) 2019 May 30, Leon Redbone (b.1949), Cyprus-born American guitar playing singer, died in Pennsylvania. His albums included “On the Track" (1975), “Double Time" (1977) and “Up a Lazy River" (1992). (SSFC, 6/2/19, p.C1) 2019 Jun 16, In Pennsylvania a shooting at a graduation party in Philadelphia left Isiaka Meite (24) dead and five other people wounded, including three teenagers. The shooter remained at large. (SFC, 6/18/19, p.A5) 2019 Jun 18, US authorities seized about 33,000 pounds of cocaine, valued at more than $1 billion, at the packer Marine Terminal in Philadelphia. Federal authorites soon raised the amount of cocaine seized to 35,000 (SFC, 6/19/19, p.A5)(SSFC, 6/23/19, p.A10) 2019 Jul 2, In Pennsylvania Bill Courtright, the former Democratic mayor of Scranton, pleaded guilty to charges that he shook down businesses for bribes and campaign contributions throughout his term and a half in office. He had resigned from office a day earlier. (SFC, 7/3/19, p.A4) 2019 Jul 18, Philadelphia police Commissioner Richard Ross suspended 17 officers for 30 days and is moving to fire 13 of them over social media posts he called (ABC News, 7/19/19) 2019 Jul 18, The Pennsylvania Gaming Control Board said that two casinos passed this week's tests to begin operating online gambling portals 24 hours a day for patrons statewide who are at least 21 years old. 2019 Jul 28, In Pennsylvania one man was killed and five others were wounded in a shooting during a rap video production in Philadelphia. 2019 Jul 31, In Pennsylvania Kathleen Kane, a former state attorney general who was convicted of leaking grand jury material, walking free after serving eight months behind bars. Kane resigned after being convicted in 2016 of perjury, obstruction and other counts for leaking grand jury material to a Philadelphia newspaper and lying about it. 2019 Jul 31, In Pennsylvania John Miller (44) was released from prison after spending more than two decades behind bars for a murder he didn't commit. The key witness against him confessed multiple times to be the real shooter and even sent a letter to Miller's mother apologizing for lying. 2019 Aug 1, The Philadelphia Police Department said seven officers whose Facebook posts were flagged in an investigation into offensive and sometimes threatening social media activity have resigned. 2019 Aug 1, Philadelphia's longest-serving sheriff, John Green (68), was sentenced to five years in prison for using bribes from a businessman to help buy two homes and then awarding him millions in city contracts. 2019 Aug 1, Florida’s Surgeon General declared a public health emergency, allowing health officials to test and treat people suspected of carrying the Hepatitis A virus. 56 new cases of Hepatitis A were reported statewide in the week since the last reporting period. Philadelphia also declared an emergency. (http://tinyurl.com/y4tdgtcz)(SSFC, 8/4/19, p.A8) 2019 Aug 5, In a Worker Adjustment and Retraining Notification Pittsburgh-based US Steel said it expects to let go fewer than 200 workers following its decision to halt production at a Michigan facility. In mid-June the company said it would idle two blast furnaces at its Great lakes and Gary Works plants, citing lower steel prices and softening demand. 2019 Aug 11, In Pennsylvania five children died and other people were rescued from an early-morning fire at a home that operated as a daycare center in 2019 Aug 15, In Pennsylvania an hours-long standoff where gunman Maurice Hill (36) shot at police, wounding six of them, as he was barricaded inside a Philadelphia home, ended early today with his arrest and no fatalities. 2019 Aug 20, Philadelphia's police Commissioner Richard Ross Jr. resigned amid allegations that members of his department engaged in sexual harassment and racial and gender discrimination against two women serving in the ranks. 2019 Sep 3, In Pennsylvania the body of Nalani Johnson, who was to turn 2 this month, was found in Pine Ridge Park in Blairsville, about 37 miles (60 km) east of Penn Hills, where authorities allege the girl was kidnapped the evening of August 31. Sharena Islam Nancy (25), who authorities say had been romantically involved with the child's father, remained in custody in Allegheny County on charges of kidnapping of a minor, custodial interference and concealment of the whereabouts of a child, all 2019 Sep 16, In Pennsylvania Dulce Maria Alavez (5) of New Jersey vanished from Bridgeton City Park about 30 miles south of Philadelphia. Authorities believe a man lured the little girl into a van and drove off. (APCBS News, 9/21/19) 2019 Sep 22, Pittsburgh police said three people died and four were hospitalized in what was believed to be a drug overdose at a single residence. Authorities were concerned about a potentially deadly batch of tainted drugs in (SFC, 9/23/19, p.A6) 2019 Oct 30, In Pennsylvania a mother, stepfather and two brothers, including a 6-year-old, were found shot to death. Maurice Louis (29), a mentally unstable son, soon confessed to killing them in their west Philadelphia home. 2019 Nov 1, A clash of storm fronts that began on Halloween created havoc that caused flooding, knocked over trees, downed power lines and damaged homes from the Deep South throughout the Northeast. More than 100,000 homes and businesses were without electricity in the Philadelphia suburbs. More than 200,000 customers were without power in New York state. In Maine, more than 120,000 customers were without power. In Vermont more than 20,000 customers were without power and in New Hampshire it was about 16,000. 2019 Nov 26, Pennsylvania overhauled its child sexual abuse laws. Gov. Tom Wolf signed legislation that give future victims of child sex abuse more time to file lawsuits and ends time limits for police to file criminal (SFC, 11/27/19, p.A5) 2019 Dec 10, The Pittsburgh Post-Gazette reported that Ravitej Reddy, the owner of Personalized Genetics LLC in Pittsburgh and Med Health Services Management in Monroeville, is scheduled to plead guilty to federal charges that he conspired with out-of-state marketing companies to pay kickbacks for lucrative lab tests at his two testing facilities. 2019 Dec 21, Joseph Segel (88), the founder of home shopping television channel QVC, died in Pennsylvania. Segel founded QVC, which stands for Quality Value Convenience, in 1986 as an alternate to the Home Shopping Network 2019 Dec 27, It was reported that Pennsylvania's Roman Catholic dioceses have paid nearly $84 million to 564 victims of sexual abuse. The tally was expected to grow as backlog claims are processed. (SFC, 12/27/19, p.A7) 2019 Dec 30, Danielle Outlaw was announced as the first female black police commissioner in (The Independent, 12/31/19) 2020 Jan 5, At least five people were killed and dozens were injured in a crash early today involving multiple vehicles on the Pennsylvania Turnpike. 2020 Jan 18, In Pennsylvania Delbert Orr Africa, a member of the Move 9 group who has been imprisoned for 42 years for a crime he says he did not commit, was released from prison. He is the eighth of the nine Move members – five men and four women – to be released or to have died while in prison. The nine were arrested and sentenced to 30 years to life following a dramatic police siege of their communal home in Philadelphia which culminated with a shootout on 8 August 1978. (The Guardian, 1/18/20) 2020 Jan 22, The Environmental Working Group (EWG) reported that the contamination of US drinking water with man-made "forever chemicals" is far worse than previously estimated with some of the highest levels found in Miami, Philadelphia and New Orleans. The chemicals, resistant to breaking down in the environment, are known as perfluoroalkyl substances, or 2020 Jan 30, In Pennsylvania a boy (4) apparently shot himself with a gun found in the home of his father Edward Williams (28). Williams told police that robbers had invaded the house. He was soon charged with involuntary (SSFC, 2/1/20, p.A8) 2020 Feb 1, It was reported that Philip Elvin Riehl's suspected $60 million scheme "targeted members of the Mennonite and Amish communities in Pennsylvania and elsewhere and is one of the largest Pennsylvania-based alleged Ponzi schemes in history". (USA Today, 2/1/20) 2020 Feb 2, Punxsutawney Phil, Pennsylvania's most famous groundhog, declared: “Spring will be early, it's a certainty". 2020 Feb 11, The US Attorney's Office in Philadelphia said five men have been arrested and charged with trying to trade in Iranian oil in violation of US trade 2020 Mar 2, In Pennsylvania the National Museum of American Jewish History in Philadelphia filed for Bankruptcy seeking protection from debt brought by construction (SFC, 3/3/20, p.A4) 2020 Mar 13, In Pennsylvania Philadelphia police Cpl. James O'Connor (46) was shot and killed early today as he served a homicide warrant at a home. Several people were arrested including the subject of the warrant, Hassan Elliott, a fugitive wanted in a robbery and slaying last year not far from the scene. 2020 Mar 25, Pennsylvania lawmakers voted to delay the state's primary election to June 2 due to the coronavirus pandemic. (SFC, 3/26/20, p.A5) 2020 Mar 30, In Pennsylvania Roderick Bliss IV (38), upset over losing his job due to the coronavirus pandemic, shot his girlfriend and then killed himself in an attempted murder-suicide in Wilson Borough. (NBC News, 4/1/20) 2020 Apr 2, Scientists at the University of Pittsburgh School of Medicine said initial tests in mice of a potential COVID-19 vaccine delivered via a fingertip-sized patch have shown it can induce an immune response against the new coronavirus at levels that might prevent infection. 2020 Apr 12, In Pennsylvania Jucontee Thomas Woewiyu, a former lietenant for Liberian warlord Charles Taylor, died in Philadelphia of COVID-19 complications. (SFC, 4/15/20, p.A3) 2020 Apr 18, Pennsylvania reported 80 new coronavirus deaths, the most on a single day, taking statewide fatalities to 836. The health department had 1,628 new cases, bringing the state’s total to 31,069. 2020 Apr 18, Paul O'Neill (84), the blunt-spoken former head of Alcoa Corp who was fired after two rocky years as US President George W. Bush's Treasury secretary, died at his home in Pittsburgh. 2020 Apr 27, Pennsylvania Gov. Tom Wolf announced he would lift some restrictions on outdoor recreation. Not just because the virus was starting to be contained, but also because people simply needed it. 2020 May 26, Former biotech executive Robert Repella (61), a resident of Ambler, Pa., pleaded guilty to a federal charge and admitted paying $50,000 to Georgetown University's former tennis coach to get his daughter admitted to the (NBC News, 5/26/20) 2020 Jun 2, In Philadelphia Joe Biden blistered President Donald Trump a day after police drove back peaceful protesters near the White House so Trump could pose with a Bible before a damaged church. 2020 Jun 3, Philadelphia took down a statue of former mayor Frank Rizzo, who aggresively policed black and gay people in the 1960s and 1970s. Mayor Jim Kenney said the statue, unveiled in 1999, represented bigotry, hatred and oppression for too many people for too long. (SFC, 6/4/20, p.A3) 2020 Jun 3, Authorities said explosions have hit 50 cash machines in and near Philadelphia since the weekend in a coordinated effort to steal them or take the money inside. Authorities also said Talib Crump (25) has been taken into custody during an undercover buy. His vehicle was found to have enough dynamite to blow up at least four more ATMs. One man (24) died a day earlier hours after he tried to break into an ATM. 2020 Jun 5, Walter Ogrod (55), a man who spent 28 years behind bars, was released from prison after a Pennsylvania judge vacated his 1996 conviction in the murder of a (NBC News, 6/6/20) 2020 Jun 8, In Pennsylvania the dismembered body of Dominique “Rem’mie" Fells, a transgender woman, was found in Philadelphia's Schuylkill River. On June 16 police identified Akhenaton Jones (38) as a suspect in the murder. 2020 Jun 21, In Pennsylvania Amish woman Linda Stoltzfoos (18) was last seen walking home from church in the Bird-in-Hand area of Lancaster County. On July 10 police arrested Justo Smoker (34) on felony kidnapping and misdemeanor false imprisonment charges. Stoltzfoos remained missing. (NBC News, 7/12/20) 2020 Jul 20, In Pennsylvania Nathan Joseph Quidetto (20), angry over a botched drug deal, fired several shots into a residence in Derry where he mistakenly thought someone involved in the deal lived, killing Tracy Marie Squib (52), who was asleep in her bed. Quidetto was arrested on July 22. 2020 Aug 12, The Philadelphia Inquirer reported that understaffing and inadequate supervision of staff and patients plagued campuses of the nonprofit Devereux Advanced Behavioral Health organization, where at least 41 intellectually disabled children have reported sexual assaults over the past quarter-century. 2020 Aug 21, Six states led by Pennsylvania sued the US Postal Service and the new postmaster general, saying service changes in recent weeks have harmed the ability of states to conduct free and fair elections. 2020 Sep 3, Speaking at a rally in Pennsylvania, Pres. Donald Trump mocked Joe Biden for wearing a mask and once again encouraged his supporters to try to vote twice if they vote by mail. (NY Times, 9/4/20) 2020 Sep 9, Tom Ridge, a former Republican governor of Pennsylvania, called on that state’s Legislature to make a small change to how mail-in ballots are counted that could make a huge difference in how quickly election results are reported in November. (Yahoo News, 9/9/20) 2020 Sep 13, In Pennsylvania protests in Lancaster degenerated into rioting that damaged the city's police headquarters and produced an arson fire that blocked a downtown intersection. Ricardo Munoz (27) was shot by police earlier in the day after a reported domestic dispute. 13 people were soon arrested and accused of committing crimes during the demonstrations. 2020 Sep 17, The Pennsylvania Supreme Court ruled that ballots had to be rejected if not enclosed in the proper security envelope. 2020 Sep 24, The US Attorney's Office in the Middle District of Pennsylvania said that nine ballots had been found in a dumpster next to the elections building with seven cast for Trump and the other two resealed inside their envelopes. A day later Luzerne County Manager said a temporary independent contractor, who was assigned to sort mail at the elections bureau "incorrectly discarded into the office trash UMOVA ballots," which is an acronym for ballots from military and overseas (ABC News, 9/25/20) 2020 Sep 25, Christian Dunbar, the treasurer of Philadelphia, was fired after federal prosecutors charged him with embezzling money from customers at a bank where he previously worked and entering into a sham marriage to win US 2020 Sep 28, In Pennsylvania officers found Mia Green (29), a Philadelphia resident and Black transgender woman, shot in the neck in the passenger’s seat of a car driven by Abdullah lbn El-Amin Jaamia (28) when he was stopped for running a stop sign. The next day Jaamia was charged with murder and 2020 Oct 1, The Pennsylvania House of Representatives canceled its floor session on the news that a second Republican member had tested positive. 2020 Oct 10, A federal judge in Pennsylvania emphatically rejected the Trump campaign’s attempt to limit the availability of drop boxes, saying that Republicans had failed to make the case that their use could lead to fraud. 2020 Oct 19, The US Supreme Court in a 4-4 vote allowed Pennsylvania to count mailed-in ballots received up to three days after the Nov. 3 election, rejecting a Republican plea in the presidential battleground state. 2020 Oct 23, Pennsylvania's Supreme Court ruled that mail-in ballots cannot be refused because a voter's signature does not appear to match the one on file, a decision that could help Democratic presidential candidate Joe 2020 Oct 23, Two Bartonsville, Pennsylvania, men and a company that ran hotels in Stroudsburg and Bartonsville were convicted of sex and drug trafficking offenses by a jury in federal court in Scranton in a case the US Attorney’s Office said is precedent setting. (USA Today, 10/29/20) 2020 Oct 26, The Philadelphia police fatally shot Walter Wallace Jr., a 27-year-old Black man, who they said was armed with a knife, touching off protests and violent clashes hours later. More than a dozen people were arrested and more than 30 officers injured in the protests. (NY Times, 10/27/20)(AP, 10/27/20) 2020 Oct 28, The US Supreme Court allowed election officials in two battleground states, Pennsylvania and North Carolina, to accept absentee ballots for several days after Election Day. (NY Times, 10/29/20) 2020 Oct 28, Philadelphia enforced a 9 p.m. curfew amid protests after the fatal police shooting of Walter Wallace Jr., a 27-year-old Black man. In the days since the shooting, people have set fire to cars, and the police have arrested dozens of people. (NY Times, 10/29/20) 2020 Oct 29, More looting was reported across Philadelphia overnight despite a citywide curfew in the wake of the deadly police shooting of Walter Wallace Jr. More than half the stores in a northeast Philadelphia strip mall were (CBS News, 10/29/20) 2020 Oct 30, The Pennsylvania National Guard arrived in Philadelphia to help quell the unrest following the Oct 26. death of Walter Wallace Jr. (SFC, 10/31/20, p.A4) 2020 Nov 2, US mall operators CBL and Pennsylvania Real Estate Investment Trust filed for bankruptcy. They said their malls will remain open as they go through the bankruptcy process. CBL, which operates 107 malls, said more than 30 of its tenants have filed for bankruptcy protection this year and are shutting stores. PREIT, based in Philadelphia, has more than 20 properties. 2020 Nov 4, City officials in Philadelphia released officer body camera footage and 911 calls in the police shooting of Walter Wallace Jr. The 27-year-old's shooting last week led to demonstrations and unrest in the city. City officials said the Philadelphia Police Department will take a number of steps to train officers to respond better to situations involving mental health crises after the death of Walter Wallace Jr. (Insider, 11/4/20)(CBS News, 11/5/20) 2020 Nov 5, The US Postal Service (USPS) said about 1,700 ballots had been identified in Pennsylvania at processing facilities during two sweeps today and were being delivered to election officials. 2020 Nov 6, Joe Biden overtook Donald Trump in the number of ballots counted in Pennsylvania, which Trump must win to have a shot at reelection. Biden now holds a nearly 6,000-vote advantage. Votes in the state were still being 2020 Nov 7, Joe Biden (77) crossed 270 Electoral College votes with a win in Pennsylvania. Biden defeated President Donald Trump to become the 46th president of the United States, positioning himself to lead a nation gripped by historic pandemic and a confluence of economic and social turmoil. It was unclear whether Trump would publicly concede. 2020 Nov 7, Pres. Donald Trump persisted in misrepresenting developments at ballot-counting centers, falsely tweeting that campaign observers in Pennsylvania were blocked from seeing what was going on as Biden overtook him in the vote count, which continues. Twitter flagged a series of Trump's tweets as dubious. 2020 Nov 12, Pennsylvania's Commonwealth Court barred county election officials from counting provisional ballots that were cast on Election Day by voters whose absentee or mail-in ballots were received on time. 2020 Nov 12, An FBI fugitive task force arrested Leonard Rayne Moses without incident at his home in Grand Blanc, Michigan. Moses was 16 when he was convicted in the 1968 killing of Mary Amplo during civil unrest in Pittsburgh following the assassination of Martin Luther King Jr. Authorities said Moses and his friends fire-bombed Amplo’s house. Badly burned, Amplo (72) died a few months later. Moses had escaped from custody while attending his grandmother’s 1971 funeral in Pittsburgh. 2020 Nov 21, US District Court Judge Matthew Brann threw out yet another lawsuit filed by the Trump campaign seeking to block the certification of the presidential election results in Pennsylvania. 2020 Nov 22, Trump campaign lawyers filed an appeal of a federal judge's decision to throw out Trump's effort to block the certification of Pennsylvania's election (The Week, 11/23/20) 2020 Nov 24, Democrat Joe Biden was certified as winner of the presidential election in Pennsylvania, culminating three weeks of vote counting and a string of failed legal challenges by President Donald Trump. 2020 Nov 25, Pennsylvania will not allow bars and restaurants to sell alcohol after 5 p.m. today, in an effort to dissuade gatherings on what is usually one of the busiest bar nights of the year. (NY Times, 11/25/20) 2020 Nov 27, The Trump campaign suffered another legal defeat when the Third Circuit Court of Appeals denied an attempt to challenge a lower court loss. The original lawsuit, based on unfounded claims of voter fraud, sought to stop or reverse the certification of Pennsylvania's vote. (The Week, 11/28/20) 2020 Dec 8, The US Supreme Court rejected a last-ditch request from Pennsylvania Republicans to overturn the state’s election results. (NY Times, 12/8/20) 2020 Dec 25, A soggy, wet and dark Christmas morning greeted more than 250,000 US power customers in New York, Pennsylvania and the Northeast who had their electricity knocked out by clobbering winds and drenching, icy rain. 2020 Dec 31, In Pennsylvania about 50 people, all in black, vandalized the historic US Customs House in Philadelphia. Seven people soon faced felony charges after at least two federal buildings were attacked. 2020 Dec 31, Former Pennsylvania Gov. Dick Thornburgh (88) died in Pittsburgh. He had made integrity and efficiency the hallmarks of his public service as a governor, US attorney general and under-secretary-general of the 2021 Jan 4, Advaccine Biopharmaceuticals Suzhou Co Ltd said it will manufacture and sell Pennsylvania-based Inovio Pharmaceuticals Inc's COVID-19 vaccine candidate in China. Inovio's vaccine candidate, INO-4800, is being tested in two trials, a mid-stage study in China in partnership with Advaccine and a mid-to-late stage trial in the United States. 2021 Jan 24, The NY Times reported that Representative Scott Perry of Pennsylvania arranged for Donald Trump earlier this month to meet Jeffrey Bossert Clark, a Justice Department official who Trump considered naming to replace Acting Attorney General Jeffrey Rosen. 2021 Feb 2, Pennsylvania's famous groundhog emerged from his tree stump to predict another six weeks of winter, just as the northeastern US got blanketed with its second day of snow. 2021 Feb 22, The US Supreme Court brought a formal end to eight lingering disputes pursued by former President Donald Trump and his allies related to the Nov. 3 presidential election including a Republican challenge to the extension of Pennsylvania's deadline to receive mail-in ballots. Clarence Thomas, Samuel Alito and Neil Gorsuch dissented from the decision not to hear the Pennsylvania case. 2021 Mar 5, The US government said it had released all families detained at the 96-bed Berks County family detention center in Leesport, Pennsylvania. The detention center will instead be used by US Immigration and Customs Enforcement to hold adults. 2021 Mar 24, The US Senate voted 52-48 to confirm former Pennsylvania Health Sec. Rachel Levine as the top assistant secretary for health, making her the highest ranking openly transgender person to serve in the US government. 2021 Mar 24, A federal indictment said that Christopher D. Casamento (42), the University of Pittsburgh’s former director of emergency management, stole more than 13,600 face masks meant for school employees and students and sold them online in the early days of the coronavirus pandemic. 2021 Apr 6, Florida, Michigan, New Jersey, New York and Pennsylvania together reported 44% of the nation's new COVID-19 infections, or nearly 197,500 new cases, in the latest available seven-day period.
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole. Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages. Do not use for reproduction, copying, pasting, or reading; exclusively for search engines. OCR for page 7 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity 1 Introduction For centuries, many students have learned mathematical knowledge—whether the rudiments of arithmetic computation or the complexities of geometric theorems—without much understanding… Of course, many students tried to make whatever sense they could of procedures such as adding common fractions or multiplying decimals. No doubt many students noticed underlying regularities in the computations they were asked to perform. Teachers who themselves were skilled in mathematics might have tried to explain those regularities. But mathematics learning has often been more a matter of memorizing than of understanding. Today it is vital that young people understand the mathematics they are learning. Whether using computer graphics on the job or spreadsheets at home, people need to move fluently back and forth between graphs, tables of data, and formulas. To make good choices in the marketplace, they must know how to spot flaws in deductive and probabilistic reasoning as well as how to estimate the results of computations…. Public policy issues of critical importance hinge on mathematical analyses. (pp. 15-16) These words are from an earlier National Research Council (NRC) report called Adding It Up: Helping Children Learn Mathematics (National Research Council, 2001a). It focused on examining the evidence about school mathematics and outlining what it means to be mathematically proficient from prekindergarten to eighth grade. The report offers much to guide current policy and practice in elementary and middle schools across the nation. Yet the report also draws attention to the importance of what happens before children enter formal schooling: “Young children show a OCR for page 8 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity remarkable ability to formulate, represent, and solve simple mathematical problems and to reason and explain their mathematical activities. They are positively disposed to do and to understand mathematics when they first encounter it” (p. 6). However, not much attention has been paid historically to teaching mathematics to young children before they enter the period of formal schooling. This stems, at least in part, from generally negative attitudes about mathematics on the part of the American public as well as to beliefs that early childhood education should consist of a nurturing environment that promotes social-emotional development, with academic content primarily focusing on language and literacy development. In fact, a majority of parents report that a positive approach to learning and language development is more important for young children than mathematics (Cannon and Ginsburg, 2008). When asked which subject was more important for her child to learn and why, one mother said (p. 249): Language. Definitely. I mean obviously they’re both [math and language] very important. But you can find people, even adults, who never learn math. I think that you could survive much better [without mathematics] than if you never learn language. I think communication is so important. If you could learn to be expressive, you could hire someone to do your math for you. Families are agents of cultural transmission, which includes conveying attitudes about mathematics. Often, mathematics is not viewed as important to young children’s cognitive development and later academic success. Evidence shows, however, that learning mathematics is vital for children’s early years and for later success in mathematics as well as better overall academic outcomes in such areas as literacy, science, and technology (e.g., Duncan et al., 2007; National Association for the Education of Young Children and National Council of Teachers of Mathematics, 2002). In addition, early childhood teachers are often uncomfortable teaching mathematics (Clements and Sarama, 2007; Copley, 2004; Ginsburg et al., 2006; Lee and Ginsburg, 2007a). Many teachers avoid teaching mathematics because of their own negative early experiences with mathematics. The quote below, by a pre-service teacher attending a top-ranked university, is illustrative: Overall, my personal experiences with math have not been good…. Throughout [my] elementary [schooling] it was either you were right or wrong…. As a result, I found math very boring and confusing. I am not a natural math learner…. I do not like the idea of teaching math to others, because I feel like I am not competent enough to teach math. I remember how hard it was when I was teaching adding and subtracting to first graders, especially when some of them did not understand it. I panicked OCR for page 9 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity when I made some mistakes myself in adding and subtracting. (Personal communication, comments by student of H. Ginsburg, Teachers College, Columbia University, September 2007.) In recent years, however, interest in mathematics as a key aspect of early childhood education has increased across both the policy and the practice communities. In 2000, the National Council of Teachers of Mathematics (NCTM), in their revision of the 1989 standards for elementary and secondary school mathematics, included prekindergarten for the first time. Also in 2000, a conference of early childhood and mathematics educators was held to focus more explicitly on standards for preschool and kindergarten children (Clements, Sarama, and DiBiase, 2004). In 2002, Good Start, Grow Smart, an early childhood-focused White House initiative, resulted in the linking of federal funding to the requirement that all states develop voluntary early learning guidelines in language, literacy, and mathematics. The now-suspended National Reporting System for assessing learning outcomes for children participating in Head Start programs, begun in 2002, originally specified four areas of focus for assessment, one of which was early mathematical skills (the other three were language-related: comprehension of spoken English, vocabulary, and letter naming) (National Research Council, 2008). Also in 2002, the National Association for the Education of Young Children and the NCTM approved a joint position statement, “Early Childhood Math: Promoting Good Beginnings,” which included recommendations to guide both policy and practice. In 2006, following on its efforts to improve language and literacy outcomes for the children it serves, the Office of Head Start turned its attention to early mathematics. It convened a mathematics working group composed of parents, local staff, researchers, and other experts in early mathematics learning and has since moved forward on developing strategies for helping Head Start and Early Head Start programs support the early mathematics learning of infants, toddlers, and preschoolers. LEARNING FROM THE RESEARCH Clearly there is growing interest in including mathematics among the learning goals for young children and in improving the teaching of mathematics in developmentally appropriate ways. Over the past several decades, significant investments have been made in research on early development and learning, much of which is ripe for examination and synthesis as it applies to early mathematics. In the past decade, the NRC has uncovered and synthesized key aspects of the knowledge about learning and development in early childhood. In the reports From Neurons to Neighborhoods: The Science of Early Child- OCR for page 10 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity hood Development (National Research Council and Institute of Medicine, 2000) and Eager to Learn: Educating Our Preschoolers (National Research Council, 2001b) the NRC directed its attention to early childhood institutions, their financing or lack of same, considerations of health and nutrition, and the social, emotional, and cultural components of this territory as they also focused special attention on early literacy. The report Early Childhood Assessment: Why, What, and How (National Research Council, 2008) identifies important outcomes for children from birth to age 5 and outlines the quality and purposes of developmental assessments. Although mathematics received attention to some degree in these studies, it was not a central focus of this work. The NRC study that resulted in the report How People Learn (National Research Council, 1999) drew on a large body of research in cognition to offer a set of powerful findings about teaching and learning at all levels and all subjects that, since its publication, have rippled across the research community. The most recent follow-on publication, How Students Learn: History, Mathematics, and Science in the Classroom (National Research Council, 2005a), provides several concrete examples of how this research on student learning can translate into improved practice, including one example in early childhood mathematics. Some additional examples of research in this territory also surfaced in Mathematical and Scientific Development in Early Childhood (National Research Council, 2005b), which captures the discussion at an NRC workshop. The previously mentioned report, Adding It Up (National Research Council, 2001a), synthesized the research on mathematics learning in prekindergarten through eighth grade and provided advice to educators, researchers, publishers, policy makers, and parents. Taken together, these prior initiatives have helped set the stage for an in-depth examination of early learning in mathematics. THE COMMITTEE’S CHARGE In order to synthesize and distill the key lessons from the relevant research, the NRC established the Committee on Early Childhood Mathematics in 2007. The majority of support for the study was provided by the Office of Head Start, under the auspices of the U.S. Department of Health and Human Services; supplementary funding was also provided by the National Institute of Child Health and Human Development, the Ewing Marion Kauffman Foundation, and the NRC. In recognition of the interdisciplinary nature of this work, the committee consists of experts in mathematics, psychology, neuroscience, early childhood education, and teacher education, as well as early childhood practitioners and policy makers. The committee worked on the study over an 18-month period. The committee charge is as follows: OCR for page 11 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity To synthesize and analyze the past research on early childhood mathematics from a number of disciplinary fields, draw out the implications for policy and practice affecting young children as they move through the preschool years and begin formal schooling, and provide research-based guidance to increase the number of young children, especially vulnerable children, prepared to get off to a strong start in learning mathematics during their first years of schooling. It is designed to capitalize on the research literature in the field and consider its various implications for policy makers, practitioners and parents. The committee will assemble the pertinent research literature from the multiple disciplines that have focused attention on the teaching and learning of mathematics by young children. They will analyze this literature in order to develop (1) appropriate mathematics learning objectives for preschool students; and (2) critical evidence-based insights related to curriculum, instruction, and teacher education for achieving these learning objectives. Finally, they will determine the implications of these findings for policy, practice, parent-child relations, future data collection and further research. See Box 1-1 for questions that the committee might address as part of its charge. BOX 1-1 Questions the Committee Might Address What does existing research tell us about what preschool children can know about mathematics, and how they develop this knowledge? Learning of which mathematical knowledge, skills, and concepts in the preschool years increases the likelihood of successful mathematics learning in school and beyond? What do international comparisons with respect to both preschoolers and primary grades students tell us about the nature of early mathematics learning and prospects for its improvement in the United States? What approaches in other countries with respect to interventions and ongoing support could usefully be applied here? What policies and practices best lay the foundation for successful mathematics learning? What can parents, preschool teachers, and other adults who interact with young children do to promote their mathematical development? How can we support the mathematical development of preschool teachers so that they will be able to promote young children’s mathematical development? How can further research in cognitive development and preschool education be focused to address issues that will lead to improvement in children’s mathematical proficiency? OCR for page 12 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity The committee cast its net widely to examine as much of the relevant research as possible. For some issues, the evidence base was limited: Throughout the report, we attempt to recognize and acknowledge the limitations of the evidence base and, at the end of the report, suggest some areas in which the scope and quality of research can be strengthened. The committee was not able to pursue in depth the entire array of possible issues related to mathematics education during early childhood; for example, we lacked the time, resources, and expertise to do a comprehensive international comparative analysis of early childhood education in mathematics. We do discuss the literature on the role of language as a shared cultural experience that shapes children’s mathematical learning. In addition, neither program evaluation nor accountability, both of which are important to children’s early mathematics education programs, is discussed at length in the report. In addressing the charge, although the committee did examine research related to the development of number and space concepts for the very early years (i.e., infancy through age 3), our focus was on children ages 3 through 6 and early mathematics education—which includes learning, teaching, teacher education, and curriculum. The committee paid special attention to the learning and teaching practices that underscore mathematical development in children from age 3 through the end of kindergarten. This age range was chosen as the focus because it provides children with key cognitive and social development opportunities associated with successful entry into formal schooling. Evidence demonstrates that preschool-age children are excited about learning and enjoy activities that develop their mathematics competencies (Gelman, 1980; Ginsburg et al., 2006; National Research Council, 2001b; Saxe et al., 1987); this period is thus critical for maintaining and enhancing motivation to learn, especially for children from disadvantaged backgrounds, because enriching early learning experiences can enable them to begin kindergarten on a more level footing with their more advantaged peers. The committee has put particular emphasis on the need to translate research on early childhood mathematics into practice for all children. Still, young children from disadvantaged backgrounds show lower levels of mathematics achievement than children from middle-class and higher status backgrounds (Clements and Sarama, 2007; Ginsburg and Russell, 1981; Hughes, 1986; Jordan, Huttenlocher, and Levine, 1994; Saxe et al., 1987; Starkey and Klein, 2000; Starkey, Klein, and Wakeley, 2004). The committee paid particular attention to issues of equity in early mathematics education throughout the report because of evidence indicating that, whereas all young children can benefit from intentional mathematics instruction, children who are at risk because of particular life circumstances OCR for page 13 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity (e.g., low socioeconomic status) will fall further behind their more affluent peers over the course of their schooling if they do not receive more intensive mathematics teaching (Starkey and Klein, 2000). The committee held four meetings, which provided opportunities for discussions with practitioners, researchers, and other experts in the field of early childhood education. These discussions helped committee members develop a better understanding of the history and positions in the various stakeholder communities as well as the reasoning behind their positions. Our analyses draw on a variety of sources. The committee examined relevant summary data produced by government agencies and professional organizations. We reviewed a wide body of interdisciplinary research and commissioned a number of research synthesis papers by experts. Often, practitioners and policy makers state that the research community is too far removed from what is actually happening in the classroom, causing researchers to make recommendations that cannot be realistically implemented. The committee is keenly aware of this concern, and thus we attempt to put forth here policy recommendations that are grounded in research as well as the action steps necessary to implement them. THE EARLY CHILDHOOD EDUCATION AND CARE DELIVERY SYSTEM One important issue that influenced the committee’s thinking about recommendations for policy and practice is the multifaceted and complex nature of the early childhood education “system.” Before the beginning of formal schooling, children spend their days in a wide variety of settings. If they are not cared for at home by their parents or relatives, children typically receive care through the country’s early education and child care system, which consists of a loosely sewn-together patchwork of different kinds of programs and providers that vary widely in their educational mission and whether they are explicitly designed to provide education services. Data from the nationally representative Early Childhood Longitudinal Study, Birth (ECLS-B) cohort show that about 60 percent of preschool-age children are in center-based care (including Head Start settings), about 21 percent of children are in home-based care arrangements, and about 20 percent have no formal child care arrangements (see Table 1-1) (Jacobson Chernoff, McPhee, and Park, 2007). In addition, about 43 percent of children younger than age 6 live in low-income families (Chau and Douglas-Hall, 2007). The high cost of high-quality early education and care is unaffordable for many low- and middle-income families (Zigler, Gilliam, and Jones, 2006). For example, the average annual cost for full-day center-based care for preschool-age OCR for page 14 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity TABLE 1-1 Children Participating in Regular Nonparental Education and Early Care, 2005-2006 (percentage) Characteristic Home-Based Center-Based Multiple Arrangements No Regular Nonparental Arrangement Relative Care Nonrelative Care Non-Head Start Head Start Total 13 8 45 13 2 20 Child Race/Ethnicity White, non-Hispanic 11 9 53 7 2 18 Black, non-Hispanic 14 4 37 25 3 16 Hispanic 16 6 31 19 1 27 Asian, non-Hispanic 16 3 55 6 2a 18 American Indian and Alaska Native, non-Hispanic 14 5 29 31 1a 20 Other, non-Hispanic 19 9 40 12 2a 18 Socioeconomic Statusb Lowest 20 percent 15 5 22 25 2 31 Middle 60 percent 15 7 44 13 2 20 Highest 20 percent 6 11 71 1 2 10 NOTE: Percentages do not sum to 100 because of rounding error. aStandard error is more than one third as large as estimate. bSocioeconomic status (SES) is a measure of social standing. This SES variable reflects the socioeconomic status of the household at the time of the preschool parent interview in 2005. The components used to create the measure of SES were as follows: father/male guardian’s education; mother/female guardian’s education; father/male guardian’s occupation; mother/female guardian’s occupation; and household income. SES was collapsed first into quintiles, then into a 20/60/20 percent distribution by collapsing the middle three quintiles. SOURCE: Jacobson Chernoff, McPhee, and Park (2007). OCR for page 15 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity children ranges from $3,794 in Mississippi to $10,920 in the District of Columbia (National Association of Child Care Resource and Referral Agencies, 2007). An increase in women’s participation in the workforce has also contributed to the demand for high-quality preschool and child care (National Research Council, 2001b). Over the past four and a half decades, women’s participation in the workforce has grown from 38 percent in 1960 to 60 percent in 2002 (U.S. Census Bureau, 2003), with 59 percent of mothers of 4-year-olds working outside the home (Jacobson Chernoff, McPhee, and Park, 2007). Head Start is a large, federally funded early childhood program that promotes school readiness for economically disadvantaged children and families; the program provides comprehensive child development services (education, health, nutritional, social, and other services). In fiscal year 2007, the program served 908,412 children, most of whom were 3- and 4-year-olds (87 percent). The reach of the program is large—in 2007 there were over 49,000 Head Start classrooms located in over 18,000 centers—which makes its policies and practices influential in early childhood education. Of the 60 percent of children in the United States who attend center-based care, approximately 22 percent are enrolled in state-funded preschool, which is the largest source of public prekindergarten (Barnett et al., 2007). Increasingly, states are moving toward state-funded preschool education to provide early education and care for children, particularly for those whose families would otherwise not be able to afford it. Georgia and Oklahoma, for example, have public preschool programs that enroll (if parents choose) 4-year-olds across the state (Barnett et al., 2007). Voluntary universal preschool is one policy option that has been suggested as a way to provide opportunities for all children, regardless of family income, to receive high-quality early education and care (Zigler et al., 2006). However, some have argued against voluntary universal preschool in favor of programs that target low-income children (e.g., Ceci and Papierno, 2005; Fuller, 2007). Ceci and Papierno (2005), for example, suggest that targeted programs are more effective in terms of financial and educational benefits because they use (often limited) early education funds to help the most disadvantaged children. Revisions to legislation and new policy initiatives have also shaped early childhood education policy in recent years. For example, beginning with the National Education Goals of 1990, the No Child Left Behind (NCLB) Act of 2001, and continuing through the 2007 reauthorization of the Head Start Act, interest in young children’s preparation for school has increased. Central aims of these pieces of legislation are to support young children’s development and learning so that they make a successful transi- OCR for page 16 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity tion into kindergarten and to provide equitable educational opportunities for all students. With the implementation of NCLB, many school districts began to place a major emphasis on the academic success of students in the early elementary grades. NCLB testing requirements do not begin until children reach third grade, but implications from the law exist for lower grades and preschool programs. The emphasis that has been placed on accountability for early childhood learning has caused concern among researchers, parents, and early education stakeholders because of the strong focus on academic development rather than the combination of academic and social-emotional development. This tension is not new; the early childhood education community has grappled with the notion that preschool programs should be more focused on academics, in contrast to the idea that they should focus instead on children’s social-emotional development. The consequences of accountability systems have brought an increased emphasis and disagreements about what should be the focus of early education and care. In addition to NCLB, Good Start, Grow Smart, President Bush’s plan to strengthen early learning (White House, n.d.), promoted accountability for preschool children’s learning outcomes in literacy and mathematics and also called for program improvements in language and literacy development. A major premise of this initiative was to close the achievement gap between socioeconomic and racial/ethnic groups. Until recently, the focus of these efforts was targeted at improving literacy and language development (e.g., Reading First and Early Reading First). However, with recent research clearly demonstrating the importance of early childhood mathematics to later success in reading and mathematics, policy makers are beginning to see the value of investing in early childhood mathematics. As discussed more fully in Chapter 8, policies aimed at changing or improving the education and learning of 3- to 6-year-olds still need to consider the diverse range of settings and characteristics of those who will do the teaching in these settings. ORGANIZATION OF THE REPORT The report is organized into four parts. Part I focuses on the research on learning and summarizes the nearly 30 years of research demonstrating that young children are able to learn foundational mathematics. As these chapters show, preschool-age children possess a well-developed understanding of informal mathematics (Ginsburg, Klein, and Starkey, 1998), and they are able to learn complex mathematics before school entry (Clements and Sarama, 2007; Ginsburg et al., 2006). Chapter 2 provides an overview of the important mathematical thinking processes and mathematical ideas for the early childhood period, summarizing the areas in which children need foundational learning opportuni- OCR for page 17 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity ties. Chapter 3 reviews the evidence about how young children’s everyday mathematics learning begins in infancy with the proximal environments in which they develop. More specifically, it focuses on cognitive development and includes a discussion of the research on infancy. Chapter 4 examines individual variation in children’s mathematics learning and performance, with particular attention to mathematics learning disabilities. The chapter also considers sources of individual variation, such as familial practices, and group variation, such as socioeconomic status and race/ethnicity. Part II focuses on a sequence of milestones for children in the core areas of number (including whole number, relations, and operations) and geometry and measurement. Chapter 5 focuses on number and operations, and Chapter 6 on geometry and measurement. In Part III the committee turns to topics of implementation of mathematics learning and teaching in the classroom context. Chapter 7 covers the research concerning standards, curriculum, teaching, and formative assessment. Chapter 8 focuses on the early childhood workforce and examines issues of teacher education and professional development. Part IV contains the committee’s synthesis of its major conclusions and outlines the recommendations that flow from these conclusions, focusing particularly on what changes are needed to improve the quality of mathematics learning for young children. The committee also lays out an agenda for future research. Appendix A is a glossary that defines terminology used throughout the report and Appendix B supplements Chapter 6. Appendix C presents biographical sketches of committee members and staff. REFERENCES AND BIBLIOGRAPHY Barnett, W.S., Hustedt, J.T., Friedman, A.H., Boyd, J.S., and Ainsworth, P. (2007). The State of Preschool 2007: State Preschool Yearbook. New Brunswick: Rutgers, The State University of New Jersey, The National Institute for Early Education Research. Available: http://nieer.org/yearbook/pdf/yearbook.pdf#page=6 [accessed August 2008]. Cannon, J., and Ginsburg, H. (2008). “Doing the math”: Maternal beliefs about early mathematics versus language learning. Early Education and Development, 19(2), 238-260. Ceci, S.J., and Papierno, P.B. (2005). The rhetoric and reality of gap closing: When the “have-nots” gain but the “haves” gain even more. American Psychologist, 60(2), 149-160. Chau, M., and Douglas-Hall, A., (2007, September). Low-income Children in the United States: National and State Trend Data, 1996-2006. Mailman School of Public Health at Columbia University, National Center for Children in Poverty. Available: http://www.nccp.org/publications/pdf/text_761.pdf [accessed August 2008]. Clements, D.H., and Sarama, J. (2007). Early childhood mathematics learning. In F.K. Lester, Jr. (Ed.), Second Handbook of Research on Mathematics Teaching and Learning (pp. 461-555). New York: Information Age. Clements, D.H., Sarama, J., and DiBiase, A. (2004). Engaging Young Children in Mathematics: Findings of the 2000 National Conference on Standards for Preschool and Kindergarten Mathematics Education. Mahwah, NJ: Erlbaum. OCR for page 18 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity Copley, J.V. (2004). The early childhood collaborative: A professional development model to communicate and implement the standards. In D.H. Clements, J. Sarama, and A-M. DiBiase (Eds.), Engaging Young Children in Mathematics (pp. 401-414). Mahwah, NJ: Erlbaum. Duncan, G.J., Dowsett, C.J., Claessens, A., Magnuson, K., Huston, A.C., Klebanov, P., Pagani, L.S., Feinstein, L., Engel, M., Brooks-Gunn, J., Sexton, H., and Duckworth, K. (2007). School readiness and later achievement. Developmental Psychology, 43, 1428-1446. Fuller, B. (2007). Standardized Childhood: The Political and Cultural Struggle over Early Education. Palo Alto, CA: Stanford University Press. Gelman, R. (1980). What young children know about numbers. Educational Psychologist, 15, 54-68. Ginsburg, H.P., and Russell, R.L. (1981). Social class and racial influences on early mathematical thinking. Monographs of the Society for Research in Child Development, 46(6), 1-68. Ginsburg, H.P., Klein, A., and Starkey, P. (1998). The development of children’s mathematical thinking: Connecting research with practice. In I. Sigel and A. Renninger (Eds.), Handbook of Child Psychology, Volume 4: Child Psychology and Practice (5th ed., pp. 401-476). New York: Wiley. Ginsburg, H.P., Goldberg Kaplan, R., Cannon, J., Cordero, M.L., Eisenband, J.G., Galanter, M., and Morgenlander, M. (2006). Helping early childhood educators to teach mathematics. In M. Zaslow and I. Martinez-Beck (Eds.), Critical Issues in Early Childhood Professional Development (pp. 171-202). Baltimore: Paul H. Brookes. Hughes, M. (1986). Children and Number. Oxford: Blackwell. Jacobson Chernoff, J., McPhee, C., and Park, J. (2007). Preschool: First Findings from the Third Follow-Up of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B). Washington, DC: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics. Jordan, N.C., Huttenlocher, J., and Levine, S.C. (1994). Assessing early arithmetic abilities: Effects of verbal and nonverbal response types on the calculation performance of middle-and low-income children. Learning and Individual Differences, 6, 413-432. Kagan, S.L., Kauerz, K., and Tarrant, K. (2008). The Early Care and Education Teaching Workforce at the Fulcrum: An Agenda for Reform. New York: Teachers College Press. Lee, J.S., and Ginsburg, H.P. (2007a). Preschool teachers’ beliefs about appropriate early literacy and mathematics education for low- and middle-socioeconomic status children. Early Education and Development, 18(1), 111-143. Lee, J.S., and Ginsburg, H.P. (2007b). What is appropriate mathematics education for four-year-olds?: Pre-kindergarten teachers’ beliefs. Journal of Early Childhood Research, 5(1), 2-31. National Association for the Education of Young Children and National Council of Teachers of Mathematics. (2002). Early Childhood Mathematics: Promoting Good Beginnings. A joint position statement. Available: http://www.naeyc.org/about/positions/pdf/psmath.pdf [accessed February 2008]. National Association of Child Care Resource and Referral Agencies. (2007). Parents and the High Price of Child Care. Arlington, VA: Author. National Council of Teachers of Mathematics. (2000). Principles and Standards for School Mathematics. Reston, VA: Author. National Research Council. (1999). How People Learn: Brain, Mind, Experience, and School. Committee on Developments in the Science of Learning. J.D. Bransford, A.L. Brown, and R.R. Cocking (Eds.). Commission on Behavioral and Social Sciences and Education. Washington, DC: National Academy Press. OCR for page 19 Mathematics Learning in Early Childhood: Paths Toward Excellence and Equity National Research Council. (2001a). Adding It Up: Helping Children Learn Mathematics. Mathematics Learning Study Committee. J. Kilpatrick, J. Swafford, and B. Findell (Eds.). Center for Education, Division of Behavioral and Social Sciences and Education. Washington, DC: National Academy Press. National Research Council. (2001b). Eager to Learn: Educating Our Preschoolers. Committee on Early Childhood Pedagogy. B.T. Bowman, M.S. Donovan, and M.S. Burns (Eds.). Commission on Behavioral and Social Sciences and Education. Washington, DC: National Academy Press. National Research Council. (2005a). How Students Learn: History, Mathematics, and Science in the Classroom. Committee on How People Learn, A Targeted Report for Teachers. M.S. Donovan and J.D. Bransford (Eds.). Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press. National Research Council. (2005b). Mathematical and Scientific Development in Early Childhood. Mathematical Sciences Education Board and Board on Science Education. A. Beatty (Rapporteur). Center for Education, Division of Behavioral and Social Sciences and Education. Washington, DC: The National Academies Press. National Research Council. (2007). 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Washington, DC: National Academy Press. Saxe, G.B., Guberman, S.R., and Gearhart, M. (1987). Social processes in early number development. Monographs of the Society for Research in Child Development, 52(2), iii-viii. Starkey, P., and Klein, A. (2000). Fostering parental support for children’s mathematical development: An intervention with Head Start families. Early Education and Development, 11, 659-680. Starkey, P., Klein, A., and Wakeley, A. (2004). Enhancing young children’s mathematical knowledge through a prekindergarten mathematics intervention. Early Childhood Research Quarterly, 19(1), 99-120. U.S. Census Bureau. (2003). No. HS-30 Marital Status of Women in the Civilian Labor Force: 1900 to 2002. Statistical Abstract of the United States. Bureau of Labor Statistics. Available: http://www.census.gov/statab/hist/HS-30.pdf [accessed August 2008]. White House. (n.d.). Good Start, Grow Smart: The Bush Administration’s Early Childhood Initiative. 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Table of Contents - 1 How do mutations in DNA sequences affect an organism? - 2 How do mutations lead to the evolution of new species? - 3 How does a mutation in DNA affect the way proteins are made? - 4 Do all mutations result in a change in the resulting protein and or phenotype? - 5 What happens if a gene is changed randomly? - 6 What happens when a variant is added to a gene? How do mutations in DNA sequences affect an organism? A mutation is a change in DNA, the hereditary material of life. An organism’s DNA affects how it looks, how it behaves, and its physiology. So a change in an organism’s DNA can cause changes in all aspects of its life. Mutations are essential to evolution; they are the raw material of genetic variation. How could a mutation or change in a DNA sequence impact the overall function of a cell? A mutation may change a trait in a way that may even be helpful, such as enabling an organism to better adapt to its environment. The simplest mutation is a point mutation. This occurs when one nucleotide base is substituted for another in a DNA sequence. The change can cause the wrong amino acid to be produced. How does mutation cause changes in the structure and function of a protein? A missense mutation is a mistake in the DNA which results in the wrong amino acid being incorporated into a protein because of change, that single DNA sequence change, results in a different amino acid codon which the ribosome recognizes. Changes in amino acid can be very important in the function of a protein. How do mutations lead to the evolution of new species? Mutation is important as the first step of evolution because it creates a new DNA sequence for a particular gene, creating a new allele. Recombination also can create a new DNA sequence (a new allele) for a specific gene through intragenic recombination. How do mutations affect an organism How do mutations affect an organism? Mutations can affect an organism by changing its physical characteristics (or phenotype) or it can impact the way DNA codes the genetic information (genotype). When mutations occur they can cause termination (death) of an organism or they can be partially lethal. What is the result of DNA mutation? Some mutations do not result in changes in the amino acid sequence of the encoded protein and can be described as silent mutations. Other mutations result in abnormal protein products. Mutations can introduce new alleles into a population of organisms and increase the population’s genetic variation. How does a mutation in DNA affect the way proteins are made? Sometimes, gene variants (also known as mutations) prevent one or more proteins from working properly. By changing a gene’s instructions for making a protein, a variant can cause a protein to malfunction or to not be produced at all. What is a mutated DNA sequence? = A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. In what way frameshift mutation sequence is different from normal DNA sequence? frameshift mutation / frame-shift mutation; frameshift A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read. A DNA sequence is a chain of many smaller molecules called nucleotides. Do all mutations result in a change in the resulting protein and or phenotype? No; only a small percentage of variants cause genetic disorders—most have no impact on health or development. For example, some variants alter a gene’s DNA sequence but do not change the function of the protein made from the gene. What causes DNA mutations? Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. How does DNA mutate? A mutation is a change in a DNA sequence. Mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses. What happens if a gene is changed randomly? By the same token, any random change in a gene’s DNA is likely to result in a protein that does not function normally or may not function at all. Such mutations are likely to be harmful. Harmful mutations may cause genetic disorders or cancer. A genetic disorder is a disease caused by a mutation in one or a few genes. What happens when a gene is deleted from a DNA sequence? Small deletions remove one or a few nucleotides within a gene, while larger deletions can remove an entire gene or several neighboring genes. The deleted DNA may alter the function of the affected protein or proteins. This variant occurs when a deletion and insertion happen at the same time in the same location in the gene. Why are DNA mutations neutral to the organism? They are neutral because they do not change the amino acids in the proteins they encode. Many other mutations have no effect on the organism because they are repaired before protein synthesis occurs. Cells have multiple repair mechanisms to fix mutations in DNA. One way DNA can be repaired is illustrated in Figure below. What happens when a variant is added to a gene? This type of variant results in a shortened protein that may function improperly, be nonfunctional, or get broken down. An insertion changes the DNA sequence by adding one or more nucleotides to the gene. As a result, the protein made from the gene may not function properly.
Scholastic Area that Course Is Active In: Mathematics Students will explore exponential functions. Extend properties of exponents to include all integer exponents. Investigate and explain characteristics of exponential functions, including domain and range, asymptotes, zeros, intercepts, intervals of increase and decrease, rates of change, and end behavior. Graph functions as transformations of f(x) = ax. Solve simple exponential equations and inequalities analytically, graphically, and by using appropriate technology. Understand and use basic exponential functions as models of real phenomena. Understand and recognize geometric sequences as exponential functions with domains that are whole numbers. Interpret the constant ratio in a geometric sequence as the base of the associated exponential function. Students will explore inverses of functions. Discuss the characteristics of functions and their inverses, including one-to-oneness, domain and range. Determine inverses of linear, quadratic, and power functions and functions of the form f(x) = a/x, including the use of restricted domains. Explore the graphs of functions and their inverses. Use composition to verify that functions are inverses of each other. Strand: Data Analysis and Probability Using sample data, students will make informal inferences about population means and standard deviations. Pose a question and collect sample data from at least two different populations. Understand and calculate the means and standard deviations of sets of data. Use means and standard deviations to compare data sets. Compare the means and standard deviations of random samples with the corresponding population parameters, including those population parameters for normal distributions. Observe that the different sample means vary from one sample to the next. Observe that the distribution of the sample means has less variability than the population distribution. Students will investigate properties of geometric figures in the coordinate plane. Determine the distance between two points. Determine the distance between a point and a line. Determine the midpoint of a segment. Understand the distance formula as an application of the Pythagorean theorem. Use the coordinate plane to investigate properties of and verify conjectures related to triangles and quadrilaterals. Students will understand and use the language of mathematical argument and justification. Use conjecture, inductive reasoning, deductive reasoning, counterexamples, and indirect proofs as appropriate. Understand and use the relationships among a statement and its converse, inverse, and contrapositive. Students will discover, prove, and apply properties of triangles, quadrilaterals, and other polygons. Determine the sum of interior and exterior angles in a polygon. Understand and use the triangle inequality, the side-angle inequality, and the exterior-angle inequality. Understand and use congurence postulates and theorems for triangles (SSS, SAS, ASA, AAS, HL). Understand, use, and prove properites of and relationship among special quadrilaterals: parallelogram, rectangle, rhombus, square, trapezoid, and kite. Find and use points of concurrency in triangles: incenter, orthocenter, circumcenter, and centroid. Students will identify and use special right triangles. Determine the lengths of sides of 30°-60°-90° triangles. Determine the lengths of sides of 45°-45°-90° triangles. Students will define and apply sine, cosine, and tangent ratios to the right triangles. Discover the relationship of the trigonometric ratios for similar triangles. Explain the relationship between the trigonometric ratios of complementary angles. Solve applications problems using the trigonometric ratios. Students will understand the properties of circles. Understand and use properties of chords, tangents, and secants as an application of triangle similarity. Understand and use properties of central, inscribed, and related angles. Use the properties of circles to solve problems involving the length of an arc and the area of a sector. Justify measurements and relationships in circles using geometric and algebraic properties. Students will find and compare the measures of spheres. Use and apply surface area and volume of a sphere. Determine the effect on surface area and volume of changing the radius or diameter of a sphere. Strand: Process Standards Students will solve problems using appropriate technology. Build new mathematical knowledge through problem solving. Solve problems that arise in mathematics and in other contexts. Apply and adapt a variety of appropriate strategies to solve problems. Monitor and reflect on the process of mathematical problem solving. Students will reason and evaluate mathematical arguments. Recognize reasoning and proof as fundamental aspects of mathematics. Make and investigate mathematical conjectures. Develop and evaluate mathematical arguments and proofs. Select and use various types of reasoning and methods of proof. Students will communicate mathematically. Organize and consolidate their mathematical thinking through communication. Communicate their mathematical thinking coherently and clearly to peers, teachers, and others. Analyze and evaluate the mathematical thinking of stratgies of others. Use the language of mathematics to express mathematical ideas precisely. Students will make connections among mathematical ideas and to other disciplines. Recognize and use connections among mathematical ideas. Understand how mathematical ideas interconnect and build on one another to produce a coherent whole. Recognize and apply mathematics in contexts outside of mathematics. Students will represent mathematics in multiple ways. Create and use representations to organize, record and communicate mathematical ideas. Select, apply, and translate among mathematical representations to solve problems. Use representations to model and interpret physical, social, and mathematical phenomena. The Guiding Sub-questions are related, relevant, and connected to exploring the Essential Question. They are higher level questions and are specific enough to guide the work of the unit. (Subquestions must be entered one at a time and updated . . . they are numbered automatically.) Begin writing a unit by establishing what you want students to know and be able to do and planning how you will know "what they know". This Assessment Plan is a general plan (specific assessment instruments are in the teaching procedures); this section should both help you to plan and to give teachers an idea of the varied types of assessment that will be used in the unit. Be sure to include informal checks of understanding, student self-assessment, and authentic assessment. Include pre and post assessment. Preparation for students includes notes on preparing the learner such as possible misconceptions students may have, ideas of pre-exposure for learners, and prerequisite lessons. It includes ideas for accelerated learning. Unit Resources include general, global resources that might include bookmarks, books, periodicals, media and software. URLs need to be provided for each resource to identify a source from which it can be obtained. Resources might include those purchased as part of an adoption. More specific resources will be referenced within the teaching procedures.
Dynamic Programming: Algorithms in Computer Science Dynamic programming is a powerful algorithmic technique widely used in computer science to solve optimization problems. This approach involves breaking down complex problems into simpler subproblems and solving them independently, subsequently combining their solutions to obtain the optimal solution for the original problem. A classic example of dynamic programming is the Knapsack Problem, where a thief needs to decide which items to include in their bag while maximizing the total value without exceeding its weight capacity. By employing this methodical approach, dynamic programming offers efficient solutions for various computational challenges. It reduces redundant computations by storing previously computed results and reusing them when necessary. Moreover, it provides an elegant way to handle overlapping subproblems that arise in many scenarios. As such, dynamic programming has found applications in diverse fields, including operations research, artificial intelligence, economics, and bioinformatics. In this article, we will delve deeper into the principles behind dynamic programming as well as explore some prominent algorithms that exemplify its efficacy in solving complex problems within these domains. What is Dynamic Programming? Imagine you are a delivery driver with multiple packages to deliver within a given timeframe. You want to optimize your route to minimize the total distance traveled and complete all deliveries efficiently. This problem can be solved using dynamic programming, a powerful algorithmic technique in computer science. Dynamic programming is an approach that breaks down complex problems into smaller subproblems, solving each one only once and storing the results for future reference. By applying this method, we can avoid redundant computations and improve efficiency. To better understand how dynamic programming works, consider the following example: Suppose you have five different locations to visit as part of your delivery route. Each location has its own associated cost, representing the distance or time it takes to reach that destination from the previous stop. The goal is to find the optimal sequence of stops that minimizes the overall cost. Key Benefits of Dynamic Programming: - Optimization: Dynamic programming allows us to solve optimization problems by finding the best solution among various possibilities. - Efficiency: By avoiding unnecessary calculations through memoization (storing previously computed results), dynamic programming significantly reduces computational overhead. - Simplicity: Complex problems can often be broken down into simpler subproblems, making them easier to tackle individually. - Versatility: Dynamic programming can be applied across diverse domains such as computer graphics, artificial intelligence, operations research, and finance. In summary, dynamic programming offers an effective strategy for solving complex problems by breaking them down into smaller subproblems and reusing their solutions. In the upcoming section on “Key Concepts in Dynamic Programming,” we will explore some fundamental ideas underlying this versatile technique without any delay. Key Concepts in Dynamic Programming Section H2: “Applications of Dynamic Programming” Imagine a scenario where you are given a set of tasks that need to be completed, each with its own associated cost. Your goal is to find the most efficient way to complete all the tasks while minimizing the overall cost. This type of problem can be solved using dynamic programming, an algorithmic technique that breaks down complex problems into smaller subproblems and solves them in an optimal manner. One example of an application of dynamic programming is in the field of project management. Consider a construction project where various activities like excavation, foundation work, plumbing, electrical wiring, etc., need to be performed. Each activity has a duration and requires certain resources. By applying dynamic programming techniques, it becomes possible to determine the optimal sequence of activities that minimizes both time and resource requirements. The benefits of utilizing dynamic programming extend beyond just project management applications. Here are some key advantages: - Optimal solutions: Dynamic programming guarantees finding the globally optimal solution by considering all possible choices at each step. - Efficiency improvement: By breaking down large problems into smaller subproblems and solving them independently, dynamic programming reduces redundant computations and improves efficiency. - Flexibility: Dynamic programming provides flexibility in choosing different strategies or approaches for solving a problem based on specific constraints or criteria. - Scalability: The approach is scalable as it can handle larger problem instances efficiently due to its divide-and-conquer nature. To better understand how dynamic programming works and its potential applications across various domains, let’s explore some real-world examples: \|Traveling Salesman Problem\|\|Logistics\|\|Shortest route connecting multiple cities\| \|Knapsack Problem\|\|Resource allocation\|\|Maximum value items within weight capacity\| \|Longest Common Subsequence\|\|DNA sequencing\|\|Similarity between two genetic sequences\| \|Matrix Chain Multiplication\|\|Optimization\|\|Minimal number of scalar multiplications\| As we can see, dynamic programming proves to be a versatile technique with diverse applications. Section H2: “Advantages of Dynamic Programming” Advantages of Dynamic Programming - Advantages of Dynamic Programming The key concepts in dynamic programming lay the foundation for understanding its numerous advantages and applications in computer science. By breaking down complex problems into smaller subproblems, dynamic programming enables efficient problem-solving through optimal solutions. This section explores some of the main advantages that make dynamic programming a powerful algorithmic approach. A hypothetical example can help illustrate the benefits of dynamic programming. Consider a delivery company aiming to optimize its routes between multiple destinations. Instead of calculating each route individually, dynamic programming allows the company to find the shortest path from one destination to another by considering intermediate stops. By storing the optimal solution at each stage, this method significantly reduces computation time and resources required. To further highlight the advantages of dynamic programming, consider these emotional responses: - Improved Efficiency: Dynamic programming eliminates redundant calculations by reusing previously computed results, leading to faster execution times. - Optimal Solutions: Through careful construction and evaluation of subproblems, dynamic programming guarantees finding an optimal solution for a given problem instance. - Simplicity: Despite dealing with complex problems, dynamic programming breaks them down into manageable components, enhancing clarity and ease of implementation. - Versatility: The flexibility offered by dynamic programming makes it suitable for solving a wide range of computational challenges across various domains. The table below summarizes these advantages: \|Improved Efficiency\|\|Avoids recalculating overlapping subproblems\| \|Optimal Solutions\|\|Guarantees finding globally optimized solutions\| \|Simplicity\|\|Breaks down complex problems into simpler subproblems\| \|Versatility\|\|Applicable to diverse computational challenges\| With its ability to improve efficiency, provide optimal solutions, offer simplicity, and adaptability across different problem domains, it is clear why dynamic programming has become a fundamental tool in computer science research and development. In the subsequent section on “Applications of Dynamic Programming,” we will explore how these advantages translate into real-world scenarios. Applications of Dynamic Programming In the previous section, we explored the advantages of utilizing dynamic programming in various computational problems. Now, let us delve deeper into the applications of this powerful algorithmic technique and understand how it can be employed to solve complex real-world challenges. To illustrate the practicality of dynamic programming, consider a scenario where an e-commerce company needs to optimize its delivery routes for maximum efficiency. By employing dynamic programming techniques, the company can efficiently determine the most optimal sequence of stops for its fleet of vehicles based on factors such as traffic conditions and package priorities. This optimization approach not only minimizes fuel consumption but also enhances customer satisfaction by ensuring timely deliveries. The application of dynamic programming spans across diverse domains due to its versatility and effectiveness. Here are some notable areas where this algorithmic technique has proved invaluable: - Financial Planning: Dynamic programming aids financial institutions in optimizing investment portfolios by considering multiple variables such as risk tolerance, market volatility, and return expectations. - DNA Sequencing: In bioinformatics research, dynamic programming plays a crucial role in aligning and comparing DNA sequences to identify genetic variations that contribute to diseases or evolutionary processes. - Resource Management: Large-scale projects involving resource allocation, such as scheduling tasks in construction projects or assigning nurses to patients in hospitals, benefit from dynamic programming algorithms that optimize utilization while minimizing costs. - Game Theory: Dynamic programming methods have significant applications in game theory scenarios like chess-playing algorithms or finding optimal strategies in competitive multiplayer games. \|Advantages of Dynamic Programming\| \|Efficiently solves complex problems\| \|Offers flexibility in problem-solving\| Embracing dynamic programming opens up new avenues for efficient problem solving across various disciplines. However, successfully implementing this technique requires careful consideration and adherence to specific steps which will be discussed further in subsequent sections. Transitioning into the next section about “Steps to Implement Dynamic Programming,” we will now explore the key procedural aspects to effectively harness dynamic programming algorithms. By following these steps, one can ensure a systematic and logical approach towards problem-solving using this powerful technique. Steps to Implement Dynamic Programming Applications of Dynamic Programming in Computer Science Consider the problem of finding the shortest path between two points in a graph. By utilizing dynamic programming, this task can be efficiently solved through a technique known as the Bellman-Ford algorithm. This algorithm breaks down the problem into smaller subproblems and solves them iteratively to ultimately find the optimal solution. One example that illustrates the power of dynamic programming is its application in optimizing network routing. In large-scale networks, where multiple paths are available for data transmission, determining the most efficient route becomes crucial. By using dynamic programming algorithms such as Dijkstra’s or Floyd-Warshall, network administrators can effectively minimize delays and congestion by selecting routes with optimized metrics like latency or bandwidth. To further understand how dynamic programming benefits computer science, let us explore some key advantages it offers: - Optimization: Dynamic programming allows for optimization problems to be solved more efficiently by breaking them down into smaller overlapping subproblems. Through reusing previously computed solutions, overall computation time is significantly reduced. - Complexity Reduction: By dividing complex problems into simpler subproblems, dynamic programming simplifies their analysis and implementation. This reduction often leads to improved code readability and maintainability. - Versatility: Dynamic programming techniques can be applied across various domains within computer science. From solving mathematical equations and analyzing genetic sequences to optimizing search algorithms and resource allocation problems – dynamic programming proves to be an invaluable tool. The table below provides a concise comparison of dynamic programming with other popular problem-solving approaches: \|Brute Force\|\|Guarantees correct solution\|\|High computational complexity\| \|Greedy Algorithms\|\|Quick execution\|\|May not always yield optimal solutions\| \|Divide and Conquer\|\|Efficient handling of large datasets\|\|Limited applicability to certain problems\| \|Dynamic Programming\|\|Optimal solutions, reduced computational complexity\|\|Requires problem to exhibit optimal substructure\| As we have seen, dynamic programming offers numerous benefits in computer science applications. By leveraging its optimization capabilities, reducing complexity, and providing versatility across various domains, this technique proves indispensable for solving complex problems efficiently. Moving forward into the subsequent section on “Challenges in Dynamic Programming,” we will explore some of the common obstacles faced when applying dynamic programming techniques and strategies to overcome them. Challenges in Dynamic Programming Dynamic programming is a powerful algorithmic technique that finds optimal solutions to problems by breaking them down into smaller, overlapping subproblems and solving each subproblem only once. This approach greatly improves the efficiency of problem-solving in computer science. To better understand dynamic programming, let’s consider an example: finding the shortest path between two nodes in a graph. Imagine we have a graph with several nodes and edges representing connections between them. Our task is to find the shortest path from node A to node B. Dynamic programming can help us achieve this efficiently by recursively solving smaller subproblems before combining their solutions. One way to implement dynamic programming for this problem is using memoization. We can create a table where each cell represents the length of the shortest path from one node to another. By filling in each cell based on previous computations, we avoid redundant calculations and speed up the overall process. To give you a clearer idea of how dynamic programming works, here are some key characteristics: - Overlapping Subproblems: The problem can be broken down into smaller subproblems that share common intermediate results. - Optimal Substructure: The optimal solution to the problem can be constructed from optimal solutions to its subproblems. - Memoization or Tabulation: Either storing computed values (memoization) or building a table bottom-up (tabulation) helps avoid recomputation and improve efficiency. - Time Complexity Improvement: Dynamic programming often reduces time complexity from exponential or factorial levels to polynomial or linear levels. Through these principles, dynamic programming enables efficient computation by avoiding unnecessary repetition and leveraging previously solved subproblems’ solutions. In summary, it offers an effective strategy for solving complex optimization problems by decomposing them into simpler ones and reusing calculated results through techniques like memoization or tabulation.
Multiplication is one of the most important concepts of mathematics as it lays a mathematical foundation. Our grade 5 math worksheets cover the 4 operations, fractions and decimals at a greater level of difficulty than previous grades. Printable Multiplication Sheets 5th Grade Fifth grade multiplication worksheets worksheet #22; 5th grade multiplication worksheets. You get the answer key. It’s highly ideal for all the table learners that are studying in the same grade. + show tags view fifth grade math topics areas of rectangles and squares All topic addition decimals fractions geometric shapes geometry multiplication subtraction temperature units of measurement. Free grade 5 multiplication worksheets to help your students improve their multiplication skills! Multiplication word problem worksheets for grade 5 this worksheet remains accessible for all due to its printable format and readily usable state. 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In astrophysics, a bow shock occurs when the magnetosphere of an astrophysical object interacts with the nearby flowing ambient plasma such as the solar wind. For Earth and other magnetized planets, it is the boundary at which the speed of the stellar wind abruptly drops as a result of its approach to the magnetopause. For stars, this boundary is typically the edge of the astrosphere, where the stellar wind meets the interstellar medium. The defining criterion of a shock wave is that the bulk velocity of the plasma drops from "supersonic" to "subsonic", where the speed of sound cs is defined by where is the ratio of specific heats, is the pressure, and is the density of the plasma. A common complication in astrophysics is the presence of a magnetic field. For instance, the charged particles making up the solar wind follow spiral paths along magnetic field lines. The velocity of each particle as it gyrates around a field line can be treated similarly to a thermal velocity in an ordinary gas, and in an ordinary gas the mean thermal velocity is roughly the speed of sound. At the bow shock, the bulk forward velocity of the wind (which is the component of the velocity parallel to the field lines about which the particles gyrate) drops below the speed at which the particles are gyrating. Around the Earth The best-studied example of a bow shock is that occurring where the Sun's wind encounters Earth's magnetopause, although bow shocks occur around all planets, both unmagnetized, such as Mars and Venus and magnetized, such as Jupiter or Saturn. Earth's bow shock is about 17 kilometres (11 mi) thick and located about 90,000 kilometres (56,000 mi) from the planet. Bow shocks form at comets as a result of the interaction between the solar wind and the cometary ionosphere. Far away from the Sun, a comet is an icy boulder without an atmosphere. As it approaches the Sun, the heat of the sunlight causes gas to be released from the cometary nucleus, creating an atmosphere called a coma. The coma is partially ionized by the sunlight, and when the solar wind passes through this ion coma, the bow shock appears. The first observations were made in the 1980s and 90s as several spacecraft flew by comets 21P/Giacobini–Zinner, 1P/Halley, and 26P/Grigg–Skjellerup. It was then found that the bow shocks at comets are wider and more gradual than the sharp planetary bow shocks seen at for example Earth. These observations were all made near perihelion when the bow shocks already were fully developed. The Rosetta spacecraft followed comet 67P/Churyumov–Gerasimenko from far out in the solar system, at a heliocentric distance of 3.6 AU, in toward perihelion at 1.24 AU, and back out again. This allowed Rosetta to observe the bow shock as it formed when the outgassing increased during the comet's journey toward the Sun. In this early state of development the shock was called the "infant bow shock". The infant bow shock is asymmetric and, relative to the distance to the nucleus, wider than fully developed bow shocks. Around the Sun For several decades, the solar wind has been thought to form a bow shock at the edge of the heliosphere, where it collides with the surrounding interstellar medium. Moving away from the Sun, the point where the solar wind flow becomes subsonic is the termination shock, the point where the interstellar medium and solar wind pressures balance is the heliopause, and the point where the flow of the interstellar medium becomes subsonic would be the bow shock. This solar bow shock was thought to lie at a distance around 230 AU from the Sun – more than twice the distance of the termination shock as encountered by the Voyager spacecraft. However, data obtained in 2012 from NASA's Interstellar Boundary Explorer (IBEX) indicates the lack of any solar bow shock. Along with corroborating results from the Voyager spacecraft, these findings have motivated some theoretical refinements; current thinking is that formation of a bow shock is prevented, at least in the galactic region through which the Sun is passing, by a combination of the strength of the local interstellar magnetic-field and of the relative velocity of the heliosphere. Around other stars Bow shocks are also a common feature in Herbig Haro objects, in which a much stronger collimated outflow of gas and dust from the star interacts with the interstellar medium, producing bright bow shocks that are visible at optical wavelengths. The following images show further evidence of bow shock existence from dense gases and plasma in the Orion Nebula. Around massive stars If a massive star is a runaway star, it can form an infrared bow-shock that is detectable in 24 μm and sometimes in 8μm of the Spitzer Space Telescope or the W3/W4-channels of WISE. In 2016 Kobulnicky et al. did create the largest spitzer/WISE bow-shock catalog to date with 709 bow-shock candidates. To get a larger bow-shock catalog The Milky Way Project (a Citizen Science project) aims to map infrared bow-shocks in the galactic plane. This larger catalog will help to understand the stellar wind of massive stars. The closest stars with infrared bow-shocks are: \|Name\|\|Distance (pc)\|\|Spectral type\|\|Belongs to\| \|bet Cru\|\|85\|\|B1IV\|\|Lower Centaurus-Crux subgroup\| \|alf Mus\|\|97\|\|B2IV\|\|Lower Centaurus-Crux subgroup\| \|alf Cru\|\|99\|\|B1V+B0.5IV\|\|Lower Centaurus-Crux subgroup\| \|zet Oph\|\|112\|\|O9.2IVnn\|\|Upper Scorpius subgroup\| \|tet Car\|\|140\|\|B0Vp\|\|IC 2602\| \|tau Sco\|\|145\|\|B0.2V\|\|Upper Scorpius subgroup\| \|del Sco\|\|150\|\|B0.3IV\|\|Upper Scorpius subgroup\| \|sig Sco\|\|214\|\|O9.5(V)+B7(V)\|\|Upper Scorpius subgroup\| Most of them belong to the Scorpius–Centaurus Association and Theta Carinae, which is the brightest star of IC 2602, might also belong to the Lower Centaurus-Crux subgroup. Epsilon Persei does not belong to this stellar association. Magnetic draping effect A similar effect, known as the magnetic draping effect, occurs when a super-Alfvenic plasma flow impacts an unmagnetized object such as what happens when the solar wind reaches the ionosphere of Venus: the flow deflects around the object draping the magnetic field along the wake flow. The condition for the flow to be super-Alfvenic means that the relative velocity between the flow and object, , is larger than the local Alfven velocity which means a large Alfvenic Mach number: . For unmagnetized and electrically conductive objects, the ambient field creates electric currents inside the object, and into the surrounding plasma, such that the flow is deflected and slowed as the time scale of magnetic dissipation is much longer than the time scale of magnetic field advection. The induced currents in turn generate magnetic fields that deflect the flow creating a bow shock. For example, the ionospheres of Mars and Venus provide the conductive environments for the interaction with the solar wind. Without an ionosphere, the flowing magnetized plasma is absorbed by the non-conductive body. The latter occurs, for example, when the solar wind interacts with Moon which has no ionosphere. In magnetic draping, the field lines are wrapped and draped around the leading side of the object creating a narrow sheath which is similar to the bow shocks in the planetary magnetospheres. The concentrated magnetic field increases until the ram pressure becomes comparable to the magnetic pressure in the sheath: where is the density of the plasma, is the draped magnetic field near the object, and is the relative speed between the plasma and the object. Magnetic draping has been detected around planets, moons, solar coronal mass ejections, and galaxies. - Sparavigna, A.C.; Marazzato, R. (10 May 2010). 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Department of Physics and Astronomy, University of Iowa. - "Cluster reveals Earth's bow shock is remarkably thin". European Space Agency. 16 November 2011. - "Cluster reveals the reformation of the Earth's bow shock". European Space Agency. 11 May 2011. - Jones, D. E.; Smith, E. J.; Slavin, J. A.; Tsurutani, B. T.; Siscoe, G. L.; Mendis, D. A. (1986). "The Bow wave of Comet Giacobini-Zinner - ICE magnetic field observations". Geophys. Res. Lett. 13 (3): 243–246. Bibcode:1986GeoRL..13..243J. doi:10.1029/GL013i003p00243. - Gringauz, K. I.; Gombosi, T. I.; Remizov, A. P.; Szemerey, I.; Verigin, M. I.; et al. (1986). "First in situ plasma and neutral gas measurements at comet Halley". Nature. 321: 282–285. Bibcode:1986Natur.321..282G. doi:10.1038/321282a0. - Neubauer, F. M.; Marschall, H.; Pohl, M.; Glassmeier, K.-H.; Musmann, G.; Mariani, F.; et al. (1993). "First results from the Giotto magnetometer experiment during the P/Grigg-Skjellerup encounter". Astronomy and Astrophysics. 268 (2): L5–L8. Bibcode:1993A&A...268L...5N. - Gunell, H.; Goetz, C.; Simon Wedlund, C.; Lindkvist, J.; Hamrin, M.; Nilsson, H.; LLera, K.; Eriksson, A.; Holmström, M. (2018). "The infant bow shock: a new frontier at a weak activity comet" (PDF). Astronomy and Astrophysics. 619: L2. Bibcode:2018A&A...619L...2G. doi:10.1051/0004-6361/201834225. - "APOD: 2002 June 24 - the Sun's Heliosphere and Heliopause". - NASA - IBEX Reveals a Missing Boundary At the Edge Of the Solar System - McComas, D. J.; Alexashov, D.; Bzowski, M.; Fahr, H.; Heerikhuisen, J.; Izmodenov, V.; Lee, M. A.; Möbius, E.; Pogorelov, N.; Schwadron, N. A.; Zank, G. P. (2012). "The Heliosphere's Interstellar Interaction: No Bow Shock". Science. 336 (6086): 1291–1293. Bibcode:2012Sci...336.1291M. doi:10.1126/science.1221054. PMID 22582011. - Detection of a Far-Infrared Bow Shock Nebula around R Hya: The First MIRIAD Results - Spitzer Science Center Press Release: Red Giant Plunging Through Space - "VizieR". vizier.u-strasbg.fr. Retrieved 2017-04-28. - "Zooniverse". www.zooniverse.org. Retrieved 2017-04-28. - melinasworldblog (2017-04-26). "Close Bowshocks". Melina's World. Retrieved 2017-04-28. - Lyutikov, M. (2006). "Magnetic draping of merging cores and radio bubbles in clusters of galaxies". Monthly Notices of the Royal Astronomical Society. 373 (1): 73–78. arXiv:astro-ph/0604178. Bibcode:2006MNRAS.373...73L. doi:10.1111/j.1365-2966.2006.10835.x. - Shore, S. N.; LaRosa, T. N. (1999). "The Galactic Center Isolated Non-thermal Filaments as Analogs of Cometary Plasma Tails". Astrophysical Journal. 521 (2): 587–590. arXiv:astro-ph/9904048. Bibcode:1999ApJ...521..587S. doi:10.1086/307601. - Pfrommer, Christoph; Dursi, L. Jonathan (2010). "Detecting the orientation of magnetic fields in galaxy clusters". Nature Physics. 6 (7): 520–526. arXiv:0911.2476. Bibcode:2010NatPh...6..520P. doi:10.1038/NPHYS1657. - Kivelson, M. G.; Russell, C. T. (1995). Introduction to Space Physics. New York: Cambridge University Press. p. 129. ISBN 978-0-521-45104-8. - Cravens, T. E. (1997). Physics of Solar System Plasmas. New York: Cambridge University Press. p. 142. ISBN 978-0-521-35280-2. - NASA Astronomy Picture of the Day: Bow shock image (BZ Cam) (28 November 2000) - NASA Astronomy Picture of the Day: Bow shock image (IRS8) (17 October 2000) - NASA Astronomy Picture of the Day: Zeta Oph: Runaway Star (8 April 2017) - Bow shock image (HD77581) - Bow shock image (LL Ori) - More on the Voyagers - Hear the Jovian bow shock (from the University of Iowa) - Cluster spacecraft makes a shocking discovery (Planetary Bow Shock)
Fractions and Repeating Decimals Worksheets Fractions are mathematical expressions that represent a part of a whole or a division of a quantity. They consist of a numerator (the number on top) and a denominator (the number on the bottom), separated by a fraction bar. Repeating decimals, on the other hand, are decimal numbers that have a pattern of digits that repeat indefinitely. A horizontal line or a set of parentheses above the repeating digits usually indicate the repeating part. These decimals can be written as fractions, where the repeating part represents the numerator and a number of nines (9s) in the denominator. In this article, you will learn more about fractions and repeating decimals with solved examples and worksheets to reinforce your learning. Fractions and Repeating Decimals We have already discussed how to convert a given fraction into the decimal form with terminating decimals.Here, we will try to understand how to convert a given fraction to repeating decimal. - Now, we consider each of the above cases separately and understand them with examples. Terminating and non-repeating decimal Example 1: ===0.5 or by long division method So, we observe that in this case the remainder is zero and hence the long division terminates and given fraction has a terminating & non-repeating decimal representation. Non-terminating and repeating decimal. Example 2: Consider Example 3: Consider So decimal representation of = 0.83333… and this repetition is denoted by putting a bar over the repeated number i.e. = 0.83333… = From the above examples, we see that the decimal representation of a fraction is non-terminating and repeating if its long division does not terminate & we have the same remainder, which cannot be exactly divided by the divisor. Convert the following fractions to their decimal form and identify whether it is a repeating decimal or not. What is a fraction? A fraction is a mathematical representation of a part of a whole or a division of a quantity. It consists of a numerator (the number on top) and a denominator (the number on the bottom) separated by a fraction bar. How do I simplify a fraction? To simplify a fraction, you need to divide both the numerator and the denominator by their greatest common divisor (GCD). This process reduces the fraction to its simplest form. How do I convert a fraction to a decimal? To convert a fraction to a decimal, divide the numerator by the denominator using long division or a calculator. The result will be a decimal representation of the fraction. How do I convert a repeating decimal to a fraction? To convert a repeating decimal to a fraction, identify the repeating part and set it as the numerator. In the denominator, write as many nines (9s) as the length of the repeating part. Simplify the fraction if possible. Can fractions and repeating decimals be used in real-life situations? Absolutely! Fractions and repeating decimals are used in various real-life scenarios, such as cooking measurements, financial calculations, and understanding probabilities. They are fundamental concepts in mathematics with practical applications in everyday life. eTutorWorld Understands Math Tutoring \| Online Math Worksheets are Important Tools Understanding graphs, charts, and opinion polls in a newspaper, for calculating house and car payments, and for choosing a long-distance telephone service are impossible without strong math skills …and the only way to develop strong math skills is by constant practice. ‘Practice makes a man perfect’ holds true for no other field better than for math. A middle or high school student must set aside a minimum of an hour for math every day. Other than textbooks, worksheets help you revise and understand concepts better. Our expert tutors prepare online maths worksheets that are age and grade-appropriate. Grade-wise math worksheets for Elementary Math, Arithmetic, Pre-Algebra, Algebra, Geometry, Trigonometry, Statistics, Pre-Calculus and Calculus can be solved to improve math skills, to get ahead or to even catch up. You may download these FREE online math worksheets in the PDF format, and then print and email us their solutions for a free evaluation and analysis by eTutorworld’smath expert tutors. You may solve these worksheets by yourself or with your peers while studying together. The Answer Key at the end of each worksheet allows for a self-evaluation. Personalized Online Tutoring eTutorWorld offers affordable one-on-one live tutoring over the web for Grades K-12, Test Prep help for Standardized tests like SCAT, CogAT, MAP, SSAT, SAT, ACT, ISEE and AP. You may schedule online tutoring lessons at your personal scheduled times, all with a Money-Back Guarantee. The first one-on-one online tutoring lesson is always FREE, no purchase obligation, no credit card required. For answers/solutions to any question or to learn concepts, take a FREE CLASS. No credit card required, no obligation to purchase. Just book a free class to meet a tutor and get help on any topic you want! Pricing for Online Tutoring \|Grade (1-12), College The Number System Expressions and Equations 1) Exponents and their properties 2) Square roots and Cube roots 3) Scientific Notation – addition, subtraction, division and multiplication 4) Equations with variables on both sides 5) Linear equations with one, zero, or infinite solutions 6) Age Word Problems 7) Solve systems of linear equations with elimination and substitution 8) Word Problems on System of Linear Equations
Strings and String Handling Instructions The 8086 microprocessor is equipped with special instructions to handle string operations. By string we mean a series of data words or bytes that reside in consecutive memory locations. The string instructions of the 8086 permit a programmer to implement operations such as to move data from one block of memory to a block elsewhere in memory. A second type of operation that is easily performed is to scan a string and data elements stored in memory looking for a specific value. Other examples are to compare the elements and two strings together in order to determine whether they are the same or different. ü Move String: MOV SB, MOV SW: An element of the string specified by the source index (SI) register with respect to the current data segment (DS) register is moved to the location specified by the destination index (DI) register with respect to the current extra segment (ES) register. The move can be performed on a byte (MOV SB) or a word (MOV SW) of data. After the move is complete, the contents of both SI & DI are automatically incremented or decremented by 1 for a byte move and by 2 for a word move. Address pointers SI and DI increment or decrement depends on how the direction flag DF is set. Example: Block move program using the move string instruction MOV AX, DATA SEG ADDR MOV DS, AX MOV ES, AX MOV SI, BLK 1 ADDR MOV DI, BLK 2 ADDR MOV CK, N NEXT: MOV SB ü Load and store strings: (LOD SB/LOD SW and STO SB/STO SW) LOD SB: Loads a byte from a string in memory into AL. The address in SI is used relative to DS to determine the address of the memory location of the string element. (AL) ¬ [(DS) + (SI)] (SI) ¬ (SI) + 1 LOD SW: The word string element at the physical address derived from DS and SI is to be loaded into AX. SI is automatically incremented by 2. (AX) ¬ [(DS) + (SI)] (SI) ¬ (SI) + 2 STO SB: Stores a byte from AL into a string location in memory. This time the contents of ES and DI are used to form the address of the storage location in memory. [(ES) + (DI)] ¬ (AL) (DI) ¬ (DI) + 1 STO SW: [(ES) + (DI)] ¬ (AX) (DI) ¬ (DI) + 2 Repeat String: REP The basic string operations must be repeated to process arrays of data. This is done by inserting a repeat prefix before the instruction that is to be repeated. Prefix REP causes the basic string operation to be repeated until the contents of register CX become equal to zero. Each time the instruction is executed, it causes CX to be tested for zero, if CX is found to be nonzero it is decremented by 1 and the basic string operation is repeated. Example: Clearing a block of memory by repeating STOSB MOV AX, 0 MOV ES, AX MOV DI, A000 MOV CX, OF REP STOSB NEXT: The prefixes REPE and REPZ stand for same function. They are meant for use with the CMPS and SCAS instructions. With REPE/REPZ the basic compare or scan operation can be repeated as long as both the contents of CX are not equal to zero and zero flag is 1. REPNE and REPNZ works similarly to REPE/REPZ except that now the operation is repeated as long as CX¹0 and ZF=0. Comparison or scanning is to be performed as long as the string elements are unequal (ZF=0) and the end of the string is not yet found (CX¹0). ü Auto Indexing for String Instructions: SI & DI addresses are either automatically incremented or decremented based on the setting of the direction flag DF. When CLD (Clear Direction Flag) is executed DF=0 permits auto increment by 1. When STD (Set Direction Flag) is executed DF=1 permits auto decrement by 1. Copyright © 2018-2020 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.
World Sight Day is an annual day of awareness held on the second Tuesday in October. The event is currently led by the International Agency for the Prevention of Blindness under the VISION2020 global initiative. Throughout the world 36 million individuals are blind, and 217 million individuals have a moderate or severe vision impairment (International Agency for the Prevention of Blindness, 2015). In honor of World Sight Day, the New England Consortium on Deafblindness is sharing information regarding three different types of visual impairments. Cortical Visual Impairment Cortical Visual Impairment (CVI) is a neurological impairment that affects a child’s vision. This type of visual impairment is caused by damage to any part of the brain that relates to visual processing. Children with CVI do not typically have ocular irregularities, although CVI may be seen with other disorders such as Strabismus. CVI occurs at a high rate among children with multiple disabilities, children with Cerebral Palsy, and children with developmental disabilities. - CVI can be difficult to diagnose due to the lack of ocular irregularities and high rate of additional disabilities. - The diagnosis of CVI occurs through medical examination and neuroimaging, and the early identification and diagnosis of CVI is integral to early intervention. - Extended response times, visual AND auditory simplicity, frequent repetition and consistency, and the use of touch cues. - The use of highly preferred colors (red and yellow), the use of light to create contrast, and limiting the glare from overhead lighting. Coloboma of the Eye Coloboma of the eye is a defect in the structure of the eye that is present from birth (common in individuals with CHARGE Syndrome). A coloboma is caused when issues occur during the development of the eyeball. Colobomas can occur on one or both eyes and can occur within different parts of the eye including the iris, lens, optic nerve, eyelid, or retina. - Due to the physical nature of the defects, a coloboma is typically identified by a pediatrician visually or during a routine eye exam. - The primary implication of a coloboma is sensitivity to light, however, the impact on a child’s vision is determined by the severity, whether or not it occurs in one or both eyes, and the location of the coloboma. - Due to the light sensitivity children may require sunglasses, tinted lenses, visors, and/or light covers in soft colors such as purple or blue to combat the harshness of overhead lights. - Black curtains may be used to cut back on glare in rooms with large amounts of natural light. - Children may require adaptations such as enlarged text, a magnifying glass, or assistive technology to access the classroom curriculum. Usher Syndrome is a genetic disorder with partial or total hearing loss and vision loss that progresses over time. Infants born with Usher Syndrome are born deaf or with a partial hearing loss. The loss of vision occurs during childhood or adolescence. Vision loss occurs as progressive loss within the visual field, resulting in tunnel vision. In addition to hearing and vision loss, Usher Syndrome can cause serious balance issues. Types of Usher Syndrome: - Usher Type I: Children are born with balance problems and profound hearing loss/deafness. By age 10, children will begin to have decreased vision at night, and by midlife individuals will present with severe vision loss. - Usher Type II: Children are born with moderate to severe hearing loss. By adolescence, night vision will begin to decrease and by midlife there will be a severe vision loss. Individuals with Usher Type II do not typically present with balance problems. - Usher Type III: Children may have progressive hearing loss in their childhood and early teenage years. Vision loss in Usher Type III varies in severity and age of onset. Vision issues often occur in the teenage years and progress to severe vision loss by midlife. Normal or near normal balance is typical in childhood, although there is a chance of balance problems in the future. - Due to hearing loss and the progressive loss of vision, programs for students with Usher Syndrome should include vocational and mobilityprograms, and academics. - Classrooms should have comfortable lighting with little glare. - Rooms should have minimal clutter and furniture should be arranged with the appropriate amount of space for students to navigate as independently as possible. - Students with Usher Syndrome may use a variety of communication methods including spoken word, sign language, and/or tactile cues. Sources: https://nei.nih.gov/faqs/cortical-visual-impairment-cvi; https://www.tsbvi.edu/component/content/article/132-syndromes/3267; http://www.familyconnect.org/info/after-the-diagnosis/browse-by-condition/coloboma/123
Johannes Kepler (27 Dec 1571 – 15 Nov 1630) laid, with Galileo, the foundation of the Scientific Revolution. He was an astronomer and mathematician, but he was also an astrologer, at a time when astrology and astronomy were inseparably combined. From Tycho Brahe’s astronomical observations of the orbit of Mars, Kepler was led to the conclusion that the planets executed elliptical orbits about the Sun, positioned at one their foci. This marked a decisive break with the tradition in astronomy, from the pre-Socratics through Ptolemy and down to Copernicus (but with the exception of Nicholas of Cusa), according to which celestial motions should conform to the most perfect of geometric figures, the circle. Kepler’s theory of elliptical orbits appeared in his Astronomia Nova in 1609. The discovery of the elliptical orbits of the planets was encoded in the first of the three laws that bear Kepler's name. The second law stated that the line joining each planet to the sun sweeps out equal areas in equal times. As Newton later showed, the equal areas law follows for any centripetal force law (it is a direct consequence of the principle of conservation of angular momentum). Kepler’s third law stated that the square of the period of orbit, divided by the cube of the major axis, is the same for each planet. It is this that is the signature of an inverse square law. Kepler’s 2nd law states that the areas A1 and A2 are swept out in equal times; the 3rd that the ratio of the squares of the period of the orbits of planets 1, 2 equals the ratio of the cubes of the lengths of the dotted lines a1 and a2. Kepler’s first astronomical treatise of 1596, the Mysterium Cosmographicum (‘Cosmographic Mystery’) was based on the model of perfectly circular orbits. It was the first major work to defend Copernicus’s heliocentric system. In it he derived the relative ratios of the radii of the planetary orbits according to his famous construction of a nesting of the five Platonic solids. The largest sphere contained in the innermost Platonic solid corresponded to the orbit of Mercury; that which bounded it and was in turn bounded by the next Platonic solid was the sphere defined by the orbit of Venus; and so on to the orbit of the Earth, Mars, Jupiter, and Saturn, which defined the sphere bounding the last of the five Platonic solids. For the sequence octahedron, icosahedron, dodecahedron, tetrahedron, and cube, he found approximate agreement with the ratios derived from Copernicus’ system (these ratios were the 'mystery' of cosmography, according to Kepler). Copernicus’ system, in contrast to Ptolomy’s, related the ratios of the orbital radii to the observable data -- the relative angles subtended by the planets at the Earth's surface. Kepler retained his system of nested Platonic solids even when replacing circular orbits by elliptical ones. Indeed, much of his subsequent work was directed to improving his solution to the ‘cosmographic mystery’. (Of course these ratios are now regarded as largely contingent, and their approximate agreement with Kepler's nesting of Platonic solids, coincidental.) Kepler also made important contributions to optics and to mathematics. His Astronomiae Pars Optica of 1604 included, among other discoveries, the inverse square law for the fall-off in intensity of a point source of light. In his Dioptrice of 1611 he set out much of the theory of classical optics, including the theory of the Galilean and Keplerian telescopes. Kepler was born near Stuttgart in Germany. His father was a mercenary, his mother a healer and herbalist, later tried (and acquitted) for witchcraft. He early showed talent in mathematics. Having attended grammar school and seminary at Maulbronn, he studied mathematics, philosophy and theology at the University of Tübingen. He was appointed to the University of Graz to teach astronomy and mathematics in 1594. In 1600 he became assistant to Tycho Brahe at his observatory near Prague. Following Tycho’s sudden death in 1601, he was appointed to replace him by the Emperor Rudolph II.
In this tutorial, I am going to show you 3 suitable ways to compute grades in excel. Although you can manually create a grade sheet, using excel will make the process very quick and easy. Also, you can compute the grades of a large number of students with the help of a few clicks. In the following section, we will see how to use the powerful functions of excel to easily compute the grades of the students. In the dataset for this tutorial, we have the columns with the names Name, Marks, and Grades. We are using a small number of students to keep things simple. For the grades, we have 5 possible ranges. Those obtaining 90 or above will get an A grade, 80 or above B grade, and so on as we shall see in the formula. We will use the following dataset to compute grades in excel. 1. Computing Grades in Excel Using the IF Function - First, double-click on cell D5 and enter the following formula: - Then, press Enter and you should see the grade in cell D5. - Finally, copy the formula to the rest of the cells below using the Fill Handle. 2. Using the VLOOKUP Function to Compute Grades The VLOOKUP function in excel searches for data in a table organized vertically. We will use this function to look up data in the Score-Criteria table in our dataset. Note that, you should organize the Score column in an ascending manner starting from 0 and then going down to 90. - To begin with, double-click on cell D5 and type in the below formula: - Now, press the Enter key and this will determine the grade of the student. - Then, copy the formula of cell D5 to the cells below by dragging the Fill Handle and excel will give you the grades of all the students. - How to Calculate Percentage of Marks in Excel (5 Simple Ways) - Apply Percentage Formula in Excel for Marksheet (7 Applications) - How to Calculate Average Percentage Increase for Marks in Excel Formula - Calculate Average Percentage of Marks in Excel (Top 4 Methods) - How to Calculate College GPA in Excel (3 Handy Approaches) 3. Applying Excel IFS Function to Calculate Grades We can use the IFS function to test multiple conditions without multiple IF statements. This will help us to compute grades in Excel with less complexity. Let us see how to use this function. - To start with, click on cell D5 and enter the following formula: - Now press Enter and the formula will calculate the grade for cell D5. - Lastly, copy the formula of cell D5 and fill the cells below with it using the Fill Handle. How to Count the Number of Students Having Certain Grades in Excel To count the number of students within each range, we will use the COUNTIF function in Excel. This function counts the number of cells in a range that meet specific criteria. - First, double-click on the cell G5 and enter the below formula: - Next, press the Enter key to confirm the formula. - As a result, excel will count the number of students with the grade F. - Then, simply drag the Fill Handle to copy the COUNTIF formula to the cells below. - Finally, you should get the number of students within each grade. Things to Remember - Make sure that you type the logical operators like >= properly. - If the numbers are inserted as percentages, then we need to define percentages in the formula as well. - It is important to note that the IF function and the IFS function are not the same. - For the first method, we need to insert the same number of closing parentheses as the number of IF functions. Download Practice Workbook You can download the practice workbook from here. I hope that this tutorial was helpful for you to compute grades in excel. You can take the methods shown in the tutorial and use them for much larger datasets. Also, if you get stuck in any step, make sure to review the detailed methods a few times. Lastly, to learn more excel techniques, follow our ExcelDemy website. If you have any queries, please let me know in the comments. - How to Calculate Subject Wise Pass or Fail with Formula in Excel - Make Automatic Marksheet in Excel (with Easy Steps) - How to Calculate Grades with Weighted Percentages in Excel - Excel Formula for Pass or Fail with Color (5 Suitable Examples) - How to Calculate GPA in Excel (with Easy Steps) - How to Average Letter Grades in Excel (4 Suitable Formulas)
Role of Central Banks And Monetary Policy A central bank refers to a monopoly and a nationalised institution which has the responsibility of producing and distribution credit and money. Currently, the central banks formulate monetary policy. The central banks are anticompetitive and are neither government agency for purposes of ensuring that the institution remains politically independent. Among the first prototypes of the modern central bank is the Bank of England which was established in the 17th century. The bank of England was also the first central bank to exercise the duty of lender of last resort for other commercial banks. Other central banks that were popular were the Reich bank of German and Napoleon’s Bank of France. The two institutions were set up to finance military operations of the government which were expensive. The European central bank managed to facilitate the smooth running of the economy evident through the ability of the government to pay wages. Such significant contribution of central banks challenged other nations to establish similar institutions to grow their economy. Currently, most of the nations have established their local central banks with regional unions like the European Union creating the European Central Bank[.Some of the central banks include the Bank of France, Bank of England and the Deutsche Bundesbank. The banks are charged with the responsibility of formulating favourable economic policies. The role of central banks and monetary policies The central banks and the fiscal policies control the money supply in the economy. The government regulates the quantity of money to keep inflation within the required rates. Mesures of increasing the amount of cash include, the central bank buying back the government bonds and bills. When they purchase them, they pay the bearers of the instrument then spend the money by paying for goods and services. Through expenditures, more money circulates within the local economy. On the other hand, when the supply of money is more than the economy, the bank issues the financial instrument and through paying the bills and bonds the banks reduce the currency in circulation (Adler, Castro, & Tovar,2016, p.184) Also, the central banks promote economic growth by ensuring that there is an adequate supply of financial resources in the economy. Therefore, the central bank engages in monetary expansion policies to supply more money to the market. Besides, the central bank can provide funds to initiate investment in the public sector. The central bank also regulates the services offered by other financial institution. The regulation is to ensure that the firms never use the client money in risky investments which are profitable for the financial institutions alone. The background and early history of the European Monetary System The Monetary System was established in the year 1979 to replace Bretton Woods Agreement in 1972. The new system was necessary because of the economic and political pressure across Europe at the time. The objective of the European Monetary was, therefore, to attain both internal and external monetary stability across Europe. The system would also, promote economic cooperation among member states. The membership to the European Monetary System has been voluntary. Nations like Denmark, France, Germany and Italy have been members voluntarily since the inception of the system. Initially, the United Kingdom joined the system and then withdrew after a two-month run on its currency reserves. However, the nation joined the European Monetary System in October 1990. The European monetary system had three essential components which were an artificial currency known as the European Currency Unit, and the exchange rates which were subject to small fluctuations. The final part of the system was the credit and loan reserves which would assist in stabilising member state currencies during the crisis. The European Currency Unit which was created in 1979 to replace the European Unit of Account that was previously used to determine the exchange rate. The value of the European currency comprised of the weighted values of the member state currencies compared to that of foreign currencies. The new technique of determining the exchange rate was considered useful in performing long-term financial transactions when compared to the European Unit of Account. The method involved macroeconomics calculations of determining the size of the national economy underlying each State’s currency to allocate weights to the money. There was also the periodic adjustment on the weighted value of the money which was done after every five years. The adjustment made the importance of strong currencies rise while the value of the weak currencies declined. However, after 1986 the changes in interest rates ensured that the currencies fluctuation remained within a narrow range keep the currencies within a close range. Besides, the European community was using the technique to prepare the budgets and also, floated loans on the international market that were denominated in the European Currency Unit. The second component of the European Monetary System aimed at achieving stabilisation of the rate of currency exchange in the Member nations. The exchange rates were fixed in 1979, and there were minimal changes at irregular intervals. Also, there was a moderate degree of floating allowed between currencies which would only rise to about six percent during periods of financial crisis in nations. The limitation in fluctuation of exchange rate motivated the financial institutions, and private investors to engage in long-term transactions with an assurance that they would not experience unexpected exchange rate gain or loss at the end of the transaction. Also, the member states had the motivation to fight inflation and avoid deficit spending. Finally, the policy spurred investment while preventing a recession. Therefore, the pegged exchange rate levels were highly satisfactory in practice for over a decade. The credit mechanism allowed member states to offer short and medium term loans during financial constraints. The short-term financing lasted between 30-45 days while the long-term long lasted five years. There was also a reserve fund set at 25 billion which was made up of 20% gold and 20% of the dollars held by each State’s central bank. The member states who received the loan were to cut on deficit spending and adopt measures that would reduce inflation. Finally, in the 1990s, the European Monetary System had the problem of conflicting economic programs among its members. The problem was mainly from the reunified Germany, and also the United Kingdom who withdrew from the program. In 1994 there was the development of European Monetary Institute which would help start European Central Bank and a common currency. In 1998 European Central Bank was formed and was charged with the responsibilities of, setting uniform monetary policy for the Eurozone nations. Finally, in 1999, the European Union members adopted the euro, for foreign exchange and electronic payments. The principle reasons for Exchange rate mechanisms problems in the early 1990s Speculative pressure to reconcile the stated exchange rate and the real rate was a significant problem facing the exchange rate mechanism. Since 1987 the exchange rates were stable, and there was no realignment of currencies. However, currencies like the peseta, the sterling, and the escudo were introduced to the exchange rate mechanism. The likelihood of experiencing another economic turbulent made the Europeans Members Union consider an incremental extension of the European Monetary System necessary for economic prosperity. The consideration was at the expense of realignment which was crucial in ensuring that the exchange rates were accurate and reflected the macroeconomic activities of each nation. Therefore, the failure to evaluate the exchange rates covered a significant source of instability. The speculation on the real exchange rate and the nominal exchange rate was attributable to different rates of inflation whereby that of German and Italy differed by 10% in 1988. Thus, making the peseta overvalued when compared to the German currency. Also, there was a complaint that the sterling pound was overvalued in 1990. The fiscal policies and competitive positions in member states also affected the exchange rate mechanism. Failure to reconcile the real and nominal exchange rate made people speculate on the exchange rate as a method of correcting the inaccuracy. Besides, the main reason why the European exchange rate regime had previously succeeded due to frequent realignments. The realignments made it possible for the European Monetary System to execute substantial cumulative changes in exchange rates which were required to counter changes in relative costs and prices gradually. Therefore, without the realignment, the exchange rate never reflected the real value of the member state currency, and thus there was speculation. Also, the desire of a single currency which could be used by all member states enhanced the rigidity of the system. After the unification of Germany officials from the Bundesbank demanded D-Mark revaluation relative to the other currencies. However, they met resistance from France, a nation that believed the realignment would jeopardise the goal of European Members Union. France also, felt that the revaluation would undermine its franc fort policy. Even the European Monetary System developed a system that contradicted it overall objective leading to the early 1990s crisis. Initially, the European Currency Unit was necessary for the exchange rate mechanism and that the divergence indicator would help identify the currencies which needed adjustment. Therefore, under the original plan adjustment would affect both the surplus and deficit countries. The arrangement caused controversies when there was the reunification of German. The claim in West Germany was that inflation rate in the European Monetary System would introduce inflationary bias into the system. Therefore, there was an intervention that put much pressure on the weak currencies when compared to the countries experiencing minimal inflation. The response saw nations with strong-currency issue more of its money, while the weak nation draws its foreign currency reserves and borrow funds (Nugent, 2017, p.3). The limited nature of foreign reserves saw states with high inflation impose restrictive fiscal policies like rising interest rates to discourage domestic inflation and importing. On the other hand, strong currencies in the European Monetary Systems like the D-mark became the nominal anchor of the system. The strength of the German currency made other members of the European Monetary System to conduct monetary policies that would maintain a stable exchange-rate. The need for realignment was eliminated by the annual rates of inflation which were consistent with the standards in Germany. The tendency of nations to imitate the financial measures of Germany made the exchange rate mechanism unstable as they pursued their domestic priorities thus misleading the other countries. Therefore, when the Bundesbank increased interest rates from 1990 to control local inflation, other European nations had to choose whether to raise their interest rates to ensure price stability but experience slow growth besides, an increase in unemployment. They also had to decide if to allow the difference between their interest rates and that of German to reduce a decision that would make investors prefer the German currency at the expense of the local currency. Explain the movement of the European single currency and evaluate the success of the introduction of the single currency A single currency across Europe has seen the benefits member states enjoy from the single market increase. Unlike previously with the Euro the nations’ conveniently purchase the factors of production at a minimum cost of transactions. Therefore, firms who are in operation because of profit margins of less than 5% percent can continue business because the devaluation of currency is within a reasonable range. Further, the Euro has strengthened the European economic zone on the global market. The Eurozone contribute gross domestic product of 14% on the international market(Murs, 2013, p. 61) Mursa, G. (2013.). euro – advantages and disadvantages. [online] Studylib.net. Available at: http://studylib.net/doc/8861631/euro-–-advantages-and-disadvantages [Accessed 26 May 2018]. Adler, G., Castro, P. and Tovar, C.E., 2016. Does central bank capital matter for monetary policy?. Open Economies Review, 27(1), pp.183-205. Nugent, N., 2017. The government and politics of the European Union. Palgrave. Sinha, A. (2012). What are the important roles played by Central Bank in developing countries?.[online] Preservearticles.com. Available at: http://www.preservearticles.com/201012291869/role-of-central-bank-in-developing-countries.html [Accessed 26 May 2018].
Given two numbers, perform multiplication, subtraction and division operations on them, using ‘+’ arithmetic operator only. Operations can be performed as follows: Subtraction :- a - b = a + (-1)b. Multiplication :- a b = a + a + a ... b times. Division :- a / b = continuously subtract b from a and count how many times we can do that. The above steps look simple, but it is slightly challenging as we can’t even use – to subtract. Subtraction is 6 Product is -54 Division is 4 Related Articles : - Add two numbers without using arithmetic operators - Subtract two numbers without using arithmetic operators - Multiply two integers without using multiplication, division and bitwise operators, and no loops This article is contributed by Sakshi Tiwari. If you like GeeksforGeeks (We know you do!) and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready. - Find Harmonic mean using Arithmetic mean and Geometric mean - Print pattern using only one loop \| Set 1 (Using setw) - Find the remainder when N is divided by 4 using Bitwise AND operator - Pointers in C and C++ \| Set 1 (Introduction, Arithmetic and Array) - Program to implement ASCII lookup table - Division without using '/' operator - Addition of two number using '-' operator - C program to check if a given year is leap year using Conditional operator - Ratio of mth and nth term in an Arithmetic Progression (AP) - Smallest number greater than or equal to N using only digits 1 to K - Program for sum of arithmetic series - Program for N-th term of Arithmetic Progression series - Program to print Arithmetic Progression series - Ternary Operator in Python - Operator Functions in Python \| Set 1 - Operator Overloading in C++ - Basics of Computer and its Operations - Number of handshakes such that a person shakes hands only once - Longest Subsequence of a String containing only vowels - Minimum swaps to make two strings equal by swapping only with third string Improved By : Mithun Kumar
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true. Imagine we have four bags containing numbers from a sequence. What numbers can we make now? How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results? Use your logical reasoning to work out how many cows and how many sheep there are in each field. Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make? Four of these clues are needed to find the chosen number on this grid and four are true but do nothing to help in finding the number. Can you sort out the clues and find the number? Find some triples of whole numbers a, b and c such that a^2 + b^2 + c^2 is a multiple of 4. Is it necessarily the case that a, b and c must all be even? If so, can you explain why? You can work out the number someone else is thinking of as follows. Ask a friend to think of any natural number less than 100. Then ask them to tell you the remainders when this number is divided by. . . . Look at three 'next door neighbours' amongst the counting numbers. Add them together. What do you notice? Make a set of numbers that use all the digits from 1 to 9, once and once only. Add them up. The result is divisible by 9. Add each of the digits in the new number. What is their sum? Now try some. . . . Look at what happens when you take a number, square it and subtract your answer. What kind of number do you get? Can you prove it? Carry out cyclic permutations of nine digit numbers containing the digits from 1 to 9 (until you get back to the first number). Prove that whatever number you choose, they will add to the same total. Pick the number of times a week that you eat chocolate. This number must be more than one but less than ten. Multiply this number by 2. Add 5 (for Sunday). Multiply by 50... Can you explain why it. . . . Who said that adding couldn't be fun? Are these statements relating to odd and even numbers always true, sometimes true or never true? Are these statements always true, sometimes true or never true? Euler discussed whether or not it was possible to stroll around Koenigsberg crossing each of its seven bridges exactly once. Experiment with different numbers of islands and bridges. Choose a couple of the sequences. Try to picture how to make the next, and the next, and the next... Can you describe your reasoning? Can you arrange the numbers 1 to 17 in a row so that each adjacent pair adds up to a square number? Spotting patterns can be an important first step - explaining why it is appropriate to generalise is the next step, and often the most interesting and important. Which set of numbers that add to 10 have the largest product? When number pyramids have a sequence on the bottom layer, some interesting patterns emerge... There are four children in a family, two girls, Kate and Sally, and two boys, Tom and Ben. How old are the children? Consider the equation 1/a + 1/b + 1/c = 1 where a, b and c are natural numbers and 0 < a < b < c. Prove that there is only one set of values which satisfy this equation. Semicircles are drawn on the sides of a rectangle ABCD. A circle passing through points ABCD carves out four crescent-shaped regions. Prove that the sum of the areas of the four crescents is equal to. . . . Replace each letter with a digit to make this addition correct. Liam's house has a staircase with 12 steps. He can go down the steps one at a time or two at time. In how many different ways can Liam go down the 12 steps? If you can copy a network without lifting your pen off the paper and without drawing any line twice, then it is traversable. Decide which of these diagrams are traversable. What happens when you add three numbers together? Will your answer be odd or even? How do you know? This addition sum uses all ten digits 0, 1, 2...9 exactly once. Find the sum and show that the one you give is the only possibility. You have been given nine weights, one of which is slightly heavier than the rest. Can you work out which weight is heavier in just two weighings of the balance? Arrange the numbers 1 to 16 into a 4 by 4 array. Choose a number. Cross out the numbers on the same row and column. Repeat this process. Add up you four numbers. Why do they always add up to 34? A little bit of algebra explains this 'magic'. Ask a friend to pick 3 consecutive numbers and to tell you a multiple of 3. Then ask them to add the four numbers and multiply by 67, and to tell you. . . . Take any whole number between 1 and 999, add the squares of the digits to get a new number. Make some conjectures about what happens in general. In how many ways can you arrange three dice side by side on a surface so that the sum of the numbers on each of the four faces (top, bottom, front and back) is equal? A paradox is a statement that seems to be both untrue and true at the same time. This article looks at a few examples and challenges you to investigate them for yourself. This article stems from research on the teaching of proof and offers guidance on how to move learners from focussing on experimental arguments to mathematical arguments and deductive reasoning. Can you cross each of the seven bridges that join the north and south of the river to the two islands, once and once only, without retracing your steps? In how many distinct ways can six islands be joined by bridges so that each island can be reached from every other island... Some puzzles requiring no knowledge of knot theory, just a careful inspection of the patterns. A glimpse of the classification of knots and a little about prime knots, crossing numbers and. . . . In this 7-sandwich: 7 1 3 1 6 4 3 5 7 2 4 6 2 5 there are 7 numbers between the 7s, 6 between the 6s etc. The article shows which values of n can make n-sandwiches and which cannot. Can you discover whether this is a fair game? Are these statements always true, sometimes true or never true? Points A, B and C are the centres of three circles, each one of which touches the other two. Prove that the perimeter of the triangle ABC is equal to the diameter of the largest circle. What does logic mean to us and is that different to mathematical logic? We will explore these questions in this article. A game for 2 players that can be played online. Players take it in turns to select a word from the 9 words given. The aim is to select all the occurrences of the same letter. Here are some examples of 'cons', and see if you can figure out where the trick is. Advent Calendar 2011 - a mathematical activity for each day during the run-up to Christmas. This article invites you to get familiar with a strategic game called "sprouts". The game is simple enough for younger children to understand, and has also provided experienced mathematicians with. . . . What can you say about the angles on opposite vertices of any cyclic quadrilateral? Working on the building blocks will give you insights that may help you to explain what is special about them.
The process described in the previous section is somewhat tedious to divide two polynomials, so we use Remainder theorem. Let be any degree polynomial greater than or equal to one and let $a$ be any real number. When a linear polynomial divides , then will be the Remainder. Let be any polynomial that is greater than or equal to degree $1$. Assume that the quotient is $q(x)$ when is divided by and, the remainder is . Applying the division algorithm, Dividend $=$ Divisor $\times$ Quotient $+$ Remainder ......................... Equation (i). Since the degree of is $1$ and the degree of is less than the degree of , the degree of . This means that is a constant, say . So we can rewrite Equation (i) as .................... Equation (ii) In particular, if , then Equation (ii) becomes . Thus, $p(a) = r$. Therefore, $p(a)$ is the remainder. Find the remainder when is divided by . Solution: Zero of is $1$, so as per remainder theorem remainder in this case will be $p(x) =$ $p(1)$ . Consider the polynomial . So that, the remainder of the polynomial is $2$.
A Mars flyby is a movement of spacecraft passing in the vicinity of the planet Mars, but not entering orbit or landing on it. Unmanned space probes have used this method to collect data on Mars, as opposed to orbiting or landing. A spacecraft designed for a flyby is also known as a "flyby bus" or "flyby spacecraft". One application of a Mars flyby is for a human mission, where after landing and staying on the surface for some time the ascent stage has a space rendezvous with another, unmanned spacecraft, that was launched separately from Earth, flying by. This would mean the ascent stage of the lander to reach the speed necessary equal to that of the spacecraft flying by, but the resources needed for Earth return would not have to enter or leave Mars orbit. The spacecraft they live in on the journey to Mars does the flyby, but the crew separates and goes into a lander. The Excursion module's ascent stage must rejoin the main spacecraft before it gets too far away. An advantage is that the resources needed for Earth return don't have to enter and leave Mars orbit, but the ascent stage has to perform space rendezvous in solar orbit and the time on Mars is constrained by the need to this. Mars cyclers orbit the Sun in such a way as to pass by Mars and the Earth on regular intervals, performing Mars flybys on regular intervals. The crews would live on the stations during the interplanetary voyages. The concept for Flyby Excursion Landing Module is that a lander and flyby would separate in solar orbit, the lander would accelerate to get to Mars first, then land on Mars meanwhile the other segment does a Mars flyby, then the lander takes off and rendezvous with the flyby segment transferring the crew over. (see also Mars Excursion Module (MEM)) Alternately, a flyby-only human mission is also possible, without detaching at Mars, but to slingshot around Mars and back to Earth. In July 1965, Mariner 4 achieved a flyby of Mars with a return of data, providing the public and scientists with dramatically closer images of Mars. During the flyby Mariner 4 took 21 pictures amounting to about 1% of the surface of Mars. Mars was not globally mapped until the Mariner 9 orbiter, which over the course of 1972 to 1973 took thousands of images up to 100m a pixel. Observations from optical ground-based Earth telescopes have to peer through the atmosphere which blurred images, typically limiting them to resolving features about 300 kilometers (190 mi) across even when Earth and Mars are closest. In October 1999, Deep Space 1 made observations of Mars after its flyby of asteroid Braille. Although this was a very distant flyby it did succeed in taking multiple infrared spectra with its MICAS instrument of the planet. In 2018, Mars Cube One (MarCO), two flyby CubeSats to relay communication from InSight lander during its EDL were launched towards Mars with the cruise stage. Both MarCOs reached Mars and successfully relayed data during the entry, descent, and landing phase of Insight on November 26, 2018.
What is a genetic algorithm? A genetic algorithm is a type of optimization algorithm that is inspired by the process of natural selection in biology. It is used to find solutions to complex problems by simulating the process of evolution through the use of computer-based “organisms” that evolve over time through the application of Darwinian principles of reproduction and natural selection. Genetic algorithms are often used to solve problems for which there is no known algorithmic solution, or for which the space of possible solutions is too large to search exhaustively. They are particularly useful for problems that involve multiple, conflicting objectives, and for which a “good” solution is difficult to define. Here is a more detailed explanation of the key components of a genetic algorithm: - Population: A population in a genetic algorithm consists of a set of potential solutions to the problem being solved. These solutions are often represented as strings of bits or other data structures, known as chromosomes. - Fitness function: A fitness function is used to evaluate the relative “fitness” of each solution in the population. The fitness function takes a solution as input and returns a numerical value that represents its quality or “fitness” for the problem being solved. - Selection: Selection is the process of selecting the most fit solutions from the population for reproduction. This is typically done through a process of ranking the solutions by fitness and selecting the top performers for reproduction. - Crossover: Crossover is the process of combining the genetic material of two solutions to create a new solution. This is often done by randomly selecting a crossover point in the chromosome of each solution and swapping the genetic material on either side of the crossover point. - Mutation: Mutation is the process of introducing random changes to the genetic material of a solution. This is done to introduce diversity into the population and prevent the solutions from becoming too similar. - Termination: The genetic algorithm terminates when a satisfactory solution is found or when a predetermined number of generations have been completed. Genetic algorithms are often used to solve a wide variety of problems, including optimization problems, machine learning problems, and search problems. They are particularly useful for problems that involve complex relationships and for which a traditional algorithmic approach would be impractical or infeasible. How a genetic algorithm is used to optimize a trading strategy Genetic algorithms can be used to optimize a trading strategy by searching for a set of input parameters that result in the best performance for the strategy. This can be done by defining a fitness function that measures the performance of the strategy for a given set of input parameters and using a genetic algorithm to search for the set of parameters that maximize the fitness function. To use a genetic algorithm to optimize a trading strategy, the following steps can be followed: - Define the input parameters for the trading strategy. These may include things like the length of moving averages, the number of stocks to hold in the portfolio, or the threshold for buying or selling a stock. - Define the fitness function. This should be a measure of the performance of the strategy for a given set of input parameters. For example, the fitness function could be the net profit or return on investment for the strategy over a given period of time. - Initialize the population. The population in a genetic algorithm consists of a set of potential solutions to the problem being solved. In this case, the solutions are the sets of input parameters for the trading strategy. The population can be initialized randomly or using some other method. - Evaluate the fitness of the solutions in the population. For each solution in the population, apply the fitness function to measure the performance of the trading strategy for that set of input parameters. - Select the fittest solutions for reproduction. Use a selection method, such as ranking or tournament selection, to select the top-performing solutions from the population for reproduction. - Crossover the solutions. Use a crossover method, such as single-point crossover or uniform crossover, to combine the genetic material of the selected solutions to create new solutions. - Mutate the solutions. Use a mutation method, such as bit-flip mutation or uniform mutation, to introduce random changes to the genetic material of the solutions. - Evaluate the fitness of the new solutions and add them to the population. - Repeat the process until a satisfactory solution is found or a predetermined number of generations have been completed. By using a genetic algorithm to optimize a trading strategy, it is possible to identify a set of input parameters that result in the best performance for the strategy. It is important to note, however, that the optimization process is based on historical data and may not necessarily result in optimal performance in the future. As with any optimization process, it is important to test the resulting strategy on out-of-sample data to ensure its robustness.
« ΠροηγούμενηΣυνέχεια » If a b be divided by + a, the quotient must be — b, because + a X - b gives - a b. If + ab be divided by — a, the quotient must be - b, because — a X - b gives + ab. If – a b be divided by — a, the quotient must be + b, because — ax + b gives - a b. The rule for signs therefore is the same as in multiplication. When the signs are alike, that is; both + or both —, the sign of the quotient must be t; but when the signs are unlike, that is, one + and the other —, the sign of the quotient must be — By the reasoning above we deriye the following rule for division of compound numbers." Arrange the dividend and divisor according to the powers of some letter. Divide the first term of the dividend by the first term of the divisor, and write the result in the quotient. Multiply all the terms of the divisor by the term of the quotient thus found, and subtract the product from the dividend. The remainder will be a new dividend, and in order to find the next term of the quotient, proceed exactly as before; and so on until there is no remainder. Sometimes, however, there will be a remainder, such that the first term of the divisor, will not divide either term of it; in which case the division can be continued no farther, and the remainder must be written over the divisor in the form of a fraction, and annexed to the quotient as in arithmetic. Divide 2a = 11 ab + 11 ao b + 13 a’ b3 by 2 a - b. ( 2a — b. at — 5 a’b+ 3 a’ b? + 8 a 63 2a - 11 ab+11a'b? +13a2b3 465 2 a—at b - 10a4b + 11 a3 b2 + 13 a2 b3 6 a’ bo + 13 a 13 8 a 64 In this example, the division may be continued until the remainder is 4 b', which cannot be divided by a, therefore it must be written over the divisor 2 a - b as a fraction and added to the quotient. The above rules are sufficient to solve all equations of the first degree. 1. Find the value of x in the equation a b? x — 20 2 ac 62 x 5 a 3 a - uu 3 First, clear it of fractions by multiplying by the denominators. Let the learner prove his results by multiplication. XXII. Miscellaneous Examples producing Simple Equations. 1. A merchant sent a venture to sea and lost one fourth of it by shipwreck; he then added $ 2250 to what remained, and sent again. This time he lost one third of what he sent. He then added $ 1000 to what remained, and sent a third time, and gained a sum equal to twice the third venture; his whole return was equal to three times his first venture. What was the value of the first venture? Śtel : 2. A man let out a certain sum of money at 6 per cent., simple interest, which interest in 10 years wanted but £ 12 to be equal to the principal. What was the principal? 3. A man let out £ 98 in two different parcels, one at 5, and the other at 6 per cent, simple interest; and the interest of the whole, in 15 years, amounted to £81. What were the two parcels? 's 4. A shepherd driving a flock of sheep in time of war, met a company of soldiers, who plundered him of one half the sheep he had and half a sheep over; the same treatment he received from a second, a third, and a fourth company, each succeeding company plundering him of one half the sheep he had left and one half a sheep over. At last he had only 7 sheep left. How many had he at first? in. 5. A man being asked how many teeth he had remaining, answered, three times as many as he had lost; and being asked how many he had lost, answered, as many as, being multiplied into part of the number he had left, would give the number he had at first. How many had he remaining, and how many had he lost? After this question is put into equation every term may be divided by X. 6. There is a rectangular field whose length is to its breadth as 3 to 2, and the number of square rods in the field is equal to 6-times the number of rods round it. Required the length and breadth of the field. 7. What two numbers are those, whose difference, sum, and product, are to each other, as the numbers 2, 3, and 5 respec 8. Generalize the above by putting a, b, and c instead of 2, 3, and 5 respectively. Let x = the greater and y=the less. Then 11. putting 10th into 3d y=sta. Enta Solve the 7th Ex. by these formulas ; also try other numbers. 9. When a company at a tavern came to pay their reckoning, they found that if there had been three persons more, they would have had a shilling apiece less to pay; and if there had been two less, they would have had to pay a shilling apiece more. How many persons were there, and how much had each to pay?
\|This article needs additional citations for verification. (June 2012) (Learn how and when to remove this template message)\| Microwave transmission is the transmission of information or energy by electromagnetic waves whose wavelengths are measured in small numbers of centimetre; these are called microwaves.[clarification needed] This part of the radio spectrum ranges across frequencies of roughly 1.0 gigahertz (GHz) to 300 GHz. These correspond to wavelengths from 30 centimeters down to 0.1 cm.[clarification needed] Although an experimental 64 km (40 mile) microwave telecommunication link across the English Channel was demonstrated in 1931, the development of radar in World War 2 provided the technology for practical exploitation of microwave communication. In the 1950s, large transcontinental microwave relay networks. consisting of chains of repeater stations linked by line-of-sight beams of microwaves were built in Europe and America to relay long distance telephone traffic and television programs between cities. Communication satellites which transferred data between ground stations by microwaves took over much long distance traffic in the 1960s. In recent years there has been an explosive increase in use of the microwave spectrum by new telecommunication technologies such as wireless networks, and direct-broadcast satellites which broadcast television and radio directly into consumers' homes. - 1 Uses - 2 Microwave radio relay - 3 Troposcatter - 4 Microwave power transmission - 5 See also - 6 References - 7 External links Microwaves are widely used for point-to-point communications because their small wavelength allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna. This allows nearby microwave equipment to use the same frequencies without interfering with each other, as lower frequency radio waves do. Another advantage is that the high frequency of microwaves gives the microwave band a very large information-carrying capacity; the microwave band has a bandwidth 30 times that of all the rest of the radio spectrum below it. A disadvantage is that microwaves are limited to line of sight propagation; they cannot pass around hills or mountains as lower frequency radio waves can. Microwave radio transmission is commonly used in point-to-point communication systems on the surface of the Earth, in satellite communications, and in deep space radio communications. Other parts of the microwave radio band are used for radars, radio navigation systems, sensor systems, and radio astronomy. The next higher part of the radio electromagnetic spectrum, where the frequencies are above 30 GHz and below 100 GHz, are called "millimeter waves" because their wavelengths are conveniently measured in millimeters, and their wavelengths range from 10 mm down to 3.0 mm.[clarification needed] Radio waves in this band are usually strongly attenuated by the Earthly atmosphere and particles contained in it, especially during wet weather. Also, in wide band of frequencies around 60 GHz, the radio waves are strongly attenuated by molecular oxygen in the atmosphere. The electronic technologies needed in the millimeter wave band are also much more difficult to utilize than those of the microwave band Wireless transmission of information - One-way (e.g. television broadcasting) and two-way telecommunication using communications satellite - Terrestrial microwave relay links in telecommunications networks including backbone or backhaul carriers in cellular networks linking BTS-BSC and BSC-MSC. Wireless transmission of power - Proposed systems e.g. for connecting solar power collecting satellites to terrestrial power grids Microwave radio relay Microwave radio relay is a technology for transmitting digital and analog signals, such as long-distance telephone calls, television programs, and computer data, between two locations on a line of sight radio path. In microwave radio relay, microwaves are transmitted between the two locations with directional antennas, forming a fixed radio connection between the two points. The requirement of a line of sight limits the distance between stations to 30 or 40 miles. Beginning in the 1940s, networks of microwave relay links, such as the AT&T Long Lines system in the U.S., carried long distance telephone calls and television programs between cities. The first system, dubbed TD-2 and built by AT&T, connected New York and Boston in 1947 with a series of eight radio relay stations. These included long daisy-chained series of such links that traversed mountain ranges and spanned continents. Much of the transcontinental traffic is now carried by cheaper optical fibers and communication satellites, but microwave relay remains important for shorter distances. Because the radio waves travel in narrow beams confined to a line-of-sight path from one antenna to the other, they don't interfere with other microwave equipment, and nearby microwave links can use the same frequencies. Antennas used must be highly directional (High gain); these antennas are installed in elevated locations such as large radio towers in order to be able to transmit across long distances. Typical types of antenna used in radio relay link installations are parabolic antennas, dielectric lens, and horn-reflector antennas, which have a diameter of up to 4 meters. Highly directive antennas permit an economical use of the available frequency spectrum, despite long transmission distances. Because of the high frequencies used, a quasi-optical line of sight between the stations is generally required. Additionally, in order to form the line of sight connection between the two stations, the first Fresnel zone must be free from obstacles so the radio waves can propagate across a nearly uninterrupted path. Obstacles in the signal field cause unwanted attenuation, and are as a result only acceptable in exceptional cases. High mountain peak or ridge positions are often ideal: Europe's highest radio relay station, the Richtfunkstation Jungfraujoch, is situated atop the Jungfraujoch ridge at an altitude of 3,705 meters (12,156 ft) above sea level. Obstacles, the curvature of the Earth, the geography of the area and reception issues arising from the use of nearby land (such as in manufacturing and forestry) are important issues to consider when planning radio links. In the planning process, it is essential that "path profiles" are produced, which provide information about the terrain and Fresnel zones affecting the transmission path. The presence of a water surface, such as a lake or river, in the mid-path region also must be taken into consideration as it can result in a near-perfect reflection (even modulated by wave or tide motions), creating multipath distortion as the two received signals ("wanted" and "unwanted") swing in and out of phase. Multipath fades are usually deep only in a small spot and a narrow frequency band, so space and/or frequency diversity schemes would be applied to mitigate these effects. The effects of atmospheric stratification cause the radio path to bend downward in a typical situation so a major distance is possible as the earth equivalent curvature increases from 6370 km to about 8500 km (a 4/3 equivalent radius effect). Rare events of temperature, humidity and pressure profile versus height, may produce large deviations and distortion of the propagation and affect transmission quality. High intensity rain and snow must also be considered as an impairment factor, especially at frequencies above 10 GHz. All previous factors, collectively known as path loss, make it necessary to compute suitable power margins, in order to maintain the link operative for a high percentage of time, like the standard 99.99% or 99.999% used in 'carrier class' services of most telecommunication operators. The longest microwave radio relay known up to date crosses the Red Sea with 360 km hop between Jebel Erba (2170m a.s.l., 20°44'46.17"N 36°50'24.65"E, Sudan) and Jebel Dakka (2572m a.s.l., 21° 5'36.89"N 40°17'29.80"E, Saudi Arabia). The link built in 1979 by Telettra allowed to proper transmit 300 telephone channels and 1 TV signal, in the 2 GHz frequency band. (Hop distance is the distance between two microwave stations) In 1931 an Anglo-French consortium headed by Andre C. Clavier demonstrated an experimental microwave relay link across the English Channel using 10 foot (3 m) dishes. Telephony, telegraph and facsimile data was transmitted over the bidirectional 1.7 GHz beams 64 km (40 miles) between Dover, UK and Calais, France. The radiated power, produced by a miniature Barkhausen-Kurz tube located at the dish's focus, was one-half watt. A 1933 military microwave link between airports at St. Inglevert, UK and Lympne, France, a distance of 56 km (35 miles) was followed in 1935 by a 300 MHz telecommunication link, the first commercial microwave relay system. The development of radar during World War II provided much of the microwave technology which made practical microwave communication links possible, particularly the klystron oscillator and techniques of designing parabolic antennas. During the 1950s the AT&T Long Lines system of microwave relay links grew to carry the majority of US long distance telephone traffic, as well as intercontinental television network signals. The prototype was called TDX and was tested with a connection between New York City and Murray Hill, the location of Bell Laboratories in 1946. The TDX system was set up between New York and Boston in 1947. The TDX was improved to the TD2, which still used klystron tubes in the transmitters, and then later to the TD3 that used solid state electronics. The main motivation in 1946 to use microwave radio instead of cable was that a large capacity could be installed quickly and at less cost. It was expected at that time that the annual operating costs for microwave radio would be greater than for cable. There were two main reasons that a large capacity had to be introduced suddenly: Pent up demand for long distance telephone service, because of the hiatus during the war years, and the new medium of television, which needed more bandwidth than radio. Though not commonly known, the US military used both portable and fixed-station microwave communications in the European Theater during WWII. Starting in the late 1940s, this continued to some degree into the 1960s, when many of these links were supplanted with tropospheric scatter or satellite systems. When the NATO military arm was formed, much of this existing equipment was transferred to communications groups. The typical communications systems used by NATO during that time period consisted of the technologies which had been developed for use by the telephone carrier entities in host countries. One example from the USA is the RCA CW-20A 1–2 GHz microwave relay system which utilized flexible UHF cable rather than the rigid waveguide required by higher frequency systems, making it ideal for tactical applications. The typical microwave relay installation or portable van had two radio systems (plus backup) connecting two LOS sites. These radios would often provide communication for 24 telephone channels of frequency division multiplexed signal (i.e. Lenkurt 33C FDM), though any channel could be designated to carry up to 18 teletype communications instead. Similar systems from Germany and other member nations were also in use. Similar systems were soon built in many countries, until the 1980s when the technology lost its share of fixed operation to newer technologies such as fiber-optic cable and communication satellites, which offer lower cost per bit.terrestrial microwave system During the Cold War, the US intelligence agencies, such as the National Security Agency (NSA), were reportedly able to intercept Soviet microwave traffic using satellites such as Rhyolite. Much of the beam of a microwave link passes the receiving antenna and radiates toward the horizon, into space. By positioning a geosynchronous satellite in the path of the beam, the microwave beam can be received. At the turn of the century, microwave radio relay systems are being used increasingly in portable radio applications. The technology is particularly suited to this application because of lower operating costs, a more efficient infrastructure, and provision of direct hardware access to the portable radio operator. A microwave link is a communications system that uses a beam of radio waves in the microwave frequency range to transmit video, audio, or data between two locations, which can be from just a few feet or meters to several miles or kilometers apart. Microwave links are commonly used by television broadcasters to transmit programmes across a country, for instance, or from an outside broadcast back to a studio. Mobile units can be camera mounted, allowing cameras the freedom to move around without trailing cables. These are often seen on the touchlines of sports fields on Steadicam systems. - Involve line of sight (LOS) communication technology - Affected greatly by environmental constraints, including rain fade - Have very limited penetration capabilities through obstacles such as hills, buildings and trees - Sensitive to high pollen count - Signals can be degradedduring Solar proton events - In communications between satellites and base stations - As backbone carriers for cellular systems - In short range indoor communications - Telecommunications, in linking remote and regional telephone exchanges to larger (main) exchanges without the need for copper/optical fibre lines. Terrestrial microwave relay links described above are limited in distance to the visual horizon, about 40 miles. Tropospheric scatter ("troposcatter" or "scatter") was a technology developed in the 1950s allow microwave communication links beyond the horizon, to a range of several hundred kilometers. The transmitter radiates a beam of microwaves into the sky, at a shallow angle above the horizon toward the receiver. As the beam passes through the troposphere a small fraction of the microwave energy is scattered back toward the ground by water vapor and dust in the air. A sensitive receiver beyond the horizon picks up this reflected signal. Signal clarity obtained by this method depends on the weather and other factors, and as a result a high level of technical difficulty is involved in the creation of a reliable over horizon radio relay link. Troposcatter links are therefore only used in special circumstances where satellites and other long distance communication channels cannot be relied on, such as in military communications. Microwave power transmission Microwave power transmission (MPT) is the use of microwaves to transmit power through outer space or the atmosphere without the need for wires. It is a sub-type of the more general wireless energy transfer methods. Following World War II, which saw the development of high-power microwave emitters known as cavity magnetrons, the idea of using microwaves to transmit power was researched. In 1964, William C. Brown demonstrated a miniature helicopter equipped with a combination antenna and rectifier device called a rectenna. The rectenna converted microwave power into electricity, allowing the helicopter to fly. In principle, the rectenna is capable of very high conversion efficiencies - over 90% in optimal circumstances. Most proposed MPT systems now usually include a phased array microwave transmitter. While these have lower efficiency levels they have the advantage of being electrically steered using no moving parts, and are easier to scale to the necessary levels that a practical MPT system requires. Common safety concerns The common reaction to microwave transmission is one of concern, as microwaves are generally perceived by the public as dangerous forms of radiation - stemming from the fact that they are used in microwave ovens. While high power microwaves can be painful and dangerous as in the United States Military's Active Denial System, MPT systems are generally proposed to have only low intensity at the rectenna. Though this would be extremely safe as the power levels would be about equal to the leakage from a microwave oven, and only slightly more than a cell phone, the relatively diffuse microwave beam necessitates a large receiving antenna area for a significant amount of energy to be transmitted. Research has involved exposing multiple generations of animals to microwave radiation of this or higher intensity, and no health issues have been found. MPT is the most commonly proposed method for transferring energy to the surface of the Earth from solar power satellites or other in-orbit power sources. MPT is occasionally proposed for the power supply in beam-powered propulsion for orbital lift space ships. Even though lasers are more commonly proposed, their low efficiency in light generation and reception has led some designers to opt for microwave based systems. Wireless Power Transmission (using microwaves) is well proven. Experiments in the tens of kilowatts have been performed at Goldstone in California in 1975 and more recently (1997) at Grand Bassin on Reunion Island. In 2008 a long range transmission experiment successfully transmitted 20 watts 92 miles (148 km) from a mountain on Maui to the main island of Hawaii. JAXA announced on 12 March 2015 that they wirelessly beamed 1.8 kilowatts 50 meters to a small receiver by converting electricity to microwaves and then back to electricity. This is the standard plan for this type of power. On 12 March 2015 Mitsubishi Heavy Industries demonstrated transmission of 10 kilowatts (kW) of power to a receiver unit located at a distance of 500 meters (m) away. - Wireless energy transfer - Fresnel zone - Passive repeater - Radio repeater - Transmitter station - Path loss - British Telecom microwave network - Trans-Canada Microwave - Antenna array (electromagnetic) - Pond, Norman H. "The Tube Guys". Russ Cochran, Publisher, 2008 p.170 - "Photos of Telettra". Facebook. Retrieved 2012-10-02. - Free, E. E. (August 1931). "Searchlight radio with the new 7 inch waves" (PDF). Radio News. New York: Radio Science Publications. 8 (2): 107–109. Retrieved March 24, 2015. - "Microwaves span the English Channel" (PDF). Short Wave Craft. New York: Popular Book Co. 6 (5): 262. September 1935. Retrieved March 24, 2015. - "Sugar Scoop Antennas Capture Microwaves." Popular Mechanics, February 1985, p. 87, bottom of page. - James Bamford, The Shadow Factory, Doubleday, 2008, ISBN 0-385-52132-4. p.176 - "Analyzing Microwave Spectra Collected by the Solar Radio Burst Locator". Digital.library.unt.edu. 2012-09-24. Retrieved 2012-10-02. - Brown, W. C. (Raytheon) (December 1965) "Experimental Airborne Microwave Supported Platform" Technical Report NO. RADC-TR- 65- 188, Air Force Systems Command. Retrieved July 9, 2012 - "Environmental Effects - the SPS Microwave Beam". Permanent.com. Retrieved 2012-10-02. - "NASA Video, date/author unknown". Retrieved 2012-10-02. - "Wireless Power Transmission for Solar Power Satellite (SPS) (Second Draft by N. Shinohara), Space Solar Power Workshop, Georgia Institute of Technology" (PDF). Retrieved 2012-10-02. - Brown., W. C. (September 1984). "The History of Power Transmission by Radio Waves". Microwave Theory and Techniques, IEEE Transactions on (Volume: 32, Issue: 9 On page(s): 1230- 1242). Bibcode:1984ITMTT..32.1230B. doi:10.1109/TMTT.1984.1132833. ISSN 0018-9480. - POINT-TO-POINT WIRELESS POWER TRANSPORTATION IN REUNION ISLAND[dead link] 48th International Astronautical Congress, Turin, Italy, 6–10 October 1997 - IAF-97-R.4.08 J. D. Lan Sun Luk, A. Celeste, P. Romanacce, L. Chane Kuang Sang, J. C. Gatina - University of La Réunion - Faculty of Science and Technology. - "Researchers Beam 'Space' Solar Power in Hawaii". Wired. 12 September 2008. Retrieved 28 May 2015. - Tarantola, Andrew (12 March 2015). "Scientists make strides in beaming solar power from space" (PDF). 162 (3856): 857–861. - Japan space scientists make wireless energy breakthrough \| Sci-Tech \| thenews.com.pk - "MHI Successfully Completes Ground Demonstration Testing of Wireless Power Transmission Technology for SSPS". 12 March 2015. - Microwave Radio Transmission Design Guide, Trevor Manning, Artech House, 1999 - RF / Microwave Design at Oxford University - AT&T's Microwave Radio-Relay Skyway introduced in 1951 - Bell System 1951 magazine ad for Microwave Radio-Relay systems. - RCA vintage magazine ad for Microwave-Radio Relay equipment used for Western Union Telegraph Co. - AT&T Long Lines Microwave Towers Remembered - AT&T Long Lines - IEEE Global History Network Microwave Link Networks
The Montreal Protocol on Substances that Deplete the Ozone Layer has been hailed as the most successful environmental treaty ever (https://www.unenvironment.org/news-and-stories/story/montreal-protocol-triumph-treaty). Yet, although our main concern about ozone depletion is the subsequent increase in harmful solar UV radiation at the Earth’s surface, no studies to date have demonstrated its effectiveness in that regard. Here we use long-term UV Index (UVI) data derived from high-quality UV spectroradiometer measurements to demonstrate its success in curbing increases in UV radiation. Without this landmark agreement, UVI values would have increased at mid-latitude locations by approximately 20% between the early 1990s and today and would approximately quadruple at mid-latitudes by 2100. In contrast, an analysis of UVI data from multiple clean-air sites shows that maximum daily UVI values have remained essentially constant over the last ~20 years in all seasons, and may even have decreased slightly in the southern hemisphere, especially in Antarctica, where effects of ozone depletion were larger. Reconstructions of the UVI from total ozone data show evidence of increasing UVI levels in the 1980s, but unfortunately, there are no high-quality UV measurements available prior to the early 1990s to confirm these increases with direct observations. Concern about ozone depletion arose primarily because of its potential to increase UV-B radiation, and the consequent effects on health and the environment1. Observations of unexpected springtime decrease in stratospheric ozone over Antarctica2 — commonly referred to as the “ozone hole” — led to the rapid adoption of the Montreal Protocol on Substances that Deplete the Ozone Layer in 19873. It has been shown that without this treaty and its subsequent Amendments and Adjustments, ozone holes would by now also be occurring over the North Pole, resulting in highly elevated UVI in the Arctic4. Even at mid-latitudes, the UVI would by now have increased markedly, and would more than double at some latitudes by the middle of the 21st century5,6,7. However, due to the success of the Montreal Protocol, ozone decreases appear to have been brought under control8, though any effects on surface UV irradiances have not previously been confirmed by measurements. We attempt to redress this issue by using an analysis of long-term UV measurements from instruments that meet the stringent requirements of the Network for the Detection of Atmospheric Composition Change (NDACC, www.ndacc.org). The network was established in 1991 to ensure the highest quality monitoring of stratospheric properties that may be influenced by mankind9. Initially it was called the Network for the Detection of Stratospheric Change (NDSC) because the focus at that time was on ozone depletion. Its scope was broadened in 2005 to become NDACC in recognition of the increasing threats from climate change and an equal focus of the network on tropospheric composition. Spectral UV measurements had been part of the network since the mid-1990s when rigorous measurement criteria were established to ensure that changes in UV due to future ozone depletion would be detectable for ozone changes as small as 1%10. However, this detection target is extremely challenging and can be met only at wavelengths of less than 300 nm11. Here we focus on the UVI, which is a more relevant quantity from a health perspective. The UVI is a scaled version of the spectral irradiance weighted by the action spectrum for erythema (reddening from sunburn) in human skin12 and is widely used to disseminate UV information to the public13. In sunlight, the UVI is dominated by the contribution from wavelengths between 300 and 315 nm. NDACC protocols (https://www.ndsc.ncep.noaa.gov/organize/protocols/appendix6/) require a measurement uncertainty of less than 5% in this wavelength range. Given this uncertainty, changes in the UVI that are caused by a 4% change in total ozone become detectable14. At the time the NDACC was established, the research community was mainly concerned about detecting increases in UV radiation due to the anticipated continuation of ozone depletion. However, because of the unprecedented success of the Montreal Protocol and its subsequent Adjustments and Amendments, the peak tropospheric chlorine loadings occurred before the turn of the century. Consequently, further ozone depletion and further UVI increases were not expected after that time. And over the longer term, a reduction in UVI is now projected due to ozone recovery1. But to date, there has been no clear demonstration of the effectiveness of the Montreal Protocol in curbing surface UV increases. This is partly due to a lack of high quality measurements prior to the early 1990s, but is also because of the compounding effects of other factors affecting UV radiation, including the effects of clouds and aerosols. We complement these measurements with projections from chemistry-climate models (CCMs), representing either the “World Avoided” or “World Expected” scenario. In the World Avoided scenario, the concentration of ozone-depleting substances continues unabated without being controlled by the Montreal Protocol. In contrast, the World Expected scenario simulates changes in ozone resulting from curbing ozone-depleting substances in full compliance with the Montreal Protocol15. All CCM model projections must assume a Representative Concentration Pathway (RCP). The Intergovernmental Panel on Climate Change (IPCC) usually consider four pathways called RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5, which are labelled according to the projected radiative forcing values in the year 2100 relative to pre-industrial values (+2.6, +4.5, +6.0, and +8.5 W/m2, respectively). Here we assume RCP 6.0 forcings16 for constituents other than the halogenated ozone-depleting substances (ODSs). In the World Avoided simulations, chlorinated or brominated source gases are assumed to increase by 3% per year from 1974 onwards. This rate of increase is modest compared to their actual rate of increase of 3.7 to 4% per year during the 1970s and 1980s before controls came into place17. In the World Expected simulations, all halogenated (chlorinated or brominated) ODSs follow the WMO (World Meteorological Organisation) A1 scenario15, which assumes compliance with the Montreal Protocol. Although now nine years old, more recent ODS scenarios differ only in minor regards from this scenario8. Data Analysis Method We first calculate seasonal mean UVI values from the ozone fields projected by these CCM models to assess their long-term projections, out to the year 2100. We then compare these projected UVI values (out to year 2020) with corresponding measurements by NDACC instruments, as well as clear-sky UVIs calculated from measured total ozone columns. We finally assess whether observed UVIs differ substantially from those inferred from CCMs that either broadly follow the observed slow decline of stratospheric halogen, or alternatively, a scenario of increasing halogen. The sites considered for analysis cover a wide range of latitudes in both hemispheres, including the tropics, mid-latitudes, and polar regions (Table 1). Note that the Brewer spectrophotometer at Thessaloniki is not part of the NDACC network and does not meet all NDACC specifications, mainly because of the limited wavelength range of the instrument (280–365 nm). In the early part of the record (prior to mid-1993), only a single monochromator version of the Brewer instrument (range 290–330 nm) was used, which also had a poorer stray light rejection at shorter wavelengths. But for the purposes of this paper, which focuses on UVI, these limitations are less important. For the calculation of UVI, a model-derived correction factor is used to account for the missing part of the spectrum. The instrument at San Diego is also not part of NDACC; however, it is identical to the instruments used in Antarctica (South Pole, Arrival Heights, and Palmer Station). Similarly, the instrument at Melbourne is not yet part of the NDACC, although it is identical to those at Lauder, Mauna Loa, and Alice Springs. We also note that at most sites, the data quality and frequency have both increased over time. For example, prior to 1996, data from Lauder were available only during periods when rain was not imminent, and for the following two years scans were disabled during (rare) rainy conditions. These limitations impart a potential clear-weather bias to early data at that site, particularly prior to 1996. Before 1997, measurements at the NSF (National Science Foundation) sites were taken only once per hour while spectral scans have been performed every 15 minutes in later years. Further analysis of data from a subset of sites suggests that these differences in the sampling protocol have virtually no effect on the results discussed in this study. At the Haute-Provence Observatory global irradiance measurements were available every 30 min prior to September 2010, and every 15 min after that date. At Villeneuve d’Ascq, scans are performed every 30 min. We considered whether to use peak daily values, peak values during a specified time window (e.g., ±1 hour of local noon), or mean values over the noon period (e.g., ±0.5 hour of local noon). Variations in seasonal mean UVIs calculated from the three quantities agreed to within ±3%, which is smaller than the measurement uncertainty of ±5%10. By using peak values instead of mean values, cloud effects on seasonal averages are reduced and time-series derived from measurements therefore agree slightly better with our modelling results, which do not take attenuation from clouds into account. The following analysis is therefore based on seasonal means of the daily maximum UVI observed within ±1 hour of local noon (12:00 UTC at Greenwich; 00:45 UTC at Lauder, etc). Data gaps were treated as described by Bernhard18. In brief, single missing days were “filled in” by calculating the average of the UVI of adjacent days. Data gaps lasting for more than one day were corrected by taking climatological variations in SZA and ozone into account. If more than 30 days were missing within a 90-day period, seasonal means were excluded from further analysis. Seasonal changes in UVI are large at mid- to high-latitudes. For latitudes poleward of 45°, UVI values in winter are less than 10% of the summer peaks. And in polar regions, the UVI reduces to zero during the polar night. Additionally, there are large day-to-day differences in UVI due to changing cloud conditions and types. To minimize these effects, we consider seasonal means of approximately 90 days (December–February, March–May, June–August, and September–November), which are also more relevant from an environmental perspective. Measurements of UVI from the sites in Table 1 are compared with values calculated for clear skies for four different ozone scenarios: ozone values projected in the World Avoided scenario from 1974 to 20656, which was calculated using the GEOS-CCM (Goddard Earth Observing System - Chemistry Climate model (NASA, USA)). ozone values projected in the World Avoided scenario from 1974 to 21007 which was calculated with the NIWA-UKCA (NIWA-UK Meteorological Office Climate Assessment) model. ozone values projected for the World Expected scenario, as calculated with the NIWA-UKCA model. This scenario is the REF-C2 experiment described by Morgenstern et al.20. In this simulation, ozone-depleting substances follow the “WMO (2010) A1” scenario, which assumes compliance with the Montreal Protocol. We note that future changes are dependent on the RCP scenario, and in particular depend on future changes in CO2, CH4, and N2O25. For example, a strong overshoot in ozone would be expected for RCP 8.5, and by the end of the 21st century, differences between N2O and CH4 scenarios may account for differences in ozone larger than 5%. For all scenarios, the clear-sky UVI at noon was interpolated from a 5D table of UVI as a function of ozone amount, solar zenith angle (SZA), altitude (pressure), aerosol optical depth, and surface albedo that had been pre-computed with the discrete-ordinate26 implementation in the TUV radiative transfer model27. Subsequent corrections were made to account for seasonal variations in Earth-Sun separation. In the World Avoided scenarios (Scenarios (2) and (3)) and World Expected scenario (Scenario (4)), the UVI was calculated for sea level with no aerosols and low surface albedo. Although both SO2 and NO2 can affect UVI, they have not been included in the clear-sky calculation. With the exception of San Diego, Thessaloniki, and Melbourne, sites considered in this paper are “clean-air” sites where the effect of absorption by these trace gases can be considered negligible. To better approximate the measurements, corresponding UVI calculations using the ozone data at each site (Scenario (1)) were computed with TUV for the altitude at each site, assuming an aerosol optical depth of 0.05 (at wavelength 0.5 µm) with a single scattering albedo of 0.90 for all sites, and a representative (annually invariant) surface albedo, ranging from 0.05 at snow-free sites, to 0.98 at the South Pole. As shown below, the comparison between the measured UVI data and the UVI data calculated from the assimilated ozone dataset (Scenario (1)) demonstrates that year-to-year variability in the UVI can be estimated with sufficient accuracy from ozone changes. The observed good agreement gives us confidence that UVI calculated from ozone for the period prior to the 1990s, when no direct UVI measurements are available, can be used to infer changes in UVI over this period. The comparisons with the two World Avoided scenarios were included to demonstrate the divergence between what has actually happened compared with what would have happened without the Montreal Protocol, using two independent model calculations. Results from Model Simulations We begin by comparing projected ozone fields from the two World Avoided models (Scenarios (2) and (3)). Predicted ozone values from these two models are compared for selected latitudes in Fig. 1. The two models are in general agreement in long-term behaviour, but also show significant differences over shorter time scales, especially at low latitudes. Close agreement is not expected at time scales of less than 5 years because there is a random component to the way modes of variability such as the quasi biennial oscillation (QBO) manifest themselves in the model runs. The systematic differences between the two models are within the usual range for chemistry-climate models28. Modelled ozone data for Scenarios (2), (3) and (4) were compared with measured ozone data (Scenario (1)) and results are provided as Supplementary Data. In general, modelled and measured total ozone column amounts (TOCs) agree reasonably well. For the reference period 1978–1987 (i.e., the period between the year when ozone measurements from space became available globally and the year when the Montreal Protocol came into effect), TOCs calculated with the NIWA-UKCA model (both World Expected and World Avoided) for sites between 45°S and 45°N – which represents 71% of the globe –are on average 8 ± 4% (±1σ) higher than the measured TOCs. The maximum bias for this latitude range is 14%. TOCs calculated with the GEOS World Avoided model are slightly smaller. It overestimates the measured TOC by 2 ± 5% on average, with a maximum bias of 12%. Deviations between the modeled and measured TOCs become larger at higher latitudes, especially in the southern hemisphere. In this latitude range, differences can exceed 20% with biases from GEOS model exceeding those from the NIWA-UKCA model. These larger biases are partly a consequence of the low ozone amounts there and partly due to the difficulty to correctly model the destruction of ozone by heterogeneous chemical processes, which strongly depend on the temperature of the lower stratosphere. Furthermore, specific sites are not necessarily well represented by the zonal means used in the model. This is especially true for high-latitude southern hemisphere sites (i.e., Ushuaia and Palmer Station) in spring when the position of the ozone hole is frequently displaced toward the South American quadrant. Some of the discrepancy may also be due to interpolation errors in the ozone assimilation during the polar night, but this is irrelevant for changes in the UVI. Even though some uncertainties remain in the models, the agreement in geographic and seasonal patterns gives confidence that they can be used to project future changes. Finally, we also note that there may be errors in the model projections if factors such as changes in the Brewer-Dobson circulation are not properly parameterised. Previous studies have also shown that the CCM models tend to overestimate ozone amounts. For example, the GEOS-CCM used previously6 has a high-ozone bias at mid to high latitudes29, which would lead to UVI estimates that are too low by approximately 10% at latitude 45° S. The green lines in Fig. 1 are the mean differences between the two models (smoothed), which shows that they depend on both latitude and time. In the longer-term, projections by the two models are in good agreement. The reasonable level of consistency between these models adds further confidence to those predictions but also illustrates some significant differences. It is interesting to note that by the year 2100, projected ozone declines are largest at high latitudes, and smallest in the tropics. By that time, the lowest mean ozone amounts would be in polar regions, and the highest in the tropics. Corresponding changes in UVI from both World Avoided simulations, as well as from the World Expected simulation (Scenario (4)) are shown in Fig. 2. By 2100 the peak UVI at mid-latitudes would have increased a factor of four, and by much larger factors at higher latitudes. Even with the high ozone bias in the model, the calculated peak UVI would have exceeded 40 in over 70% of the area of the globe. Because of the latitudinal redistribution in ozone described above, at the end of the 21st century, the largest clear-sky UVI values projected at mid-latitudes are similar to those in the tropics. This is in contrast to the present situation, where the peak UVI occurs in the tropics. Time series for lauder We now compare these UVI projections from the CCM models with observed changes in UVI and with those expected from clear-sky calculations using the assimilated ozone values. Results for Lauder are shown in Fig. 3. Figure 3a displays the time series of daily ozone derived from the NIWA/BS ozone assimilation for the period since satellite measurements became available. In Fig. 3b, the peak UVI measured within one hour of local noon is compared with the UVI calculated for clear-sky conditions using the NIWA/BS ozone data. There is good agreement in the seasonal range between measured and modelled UVI. Because of the large seasonal and day-to-day variability, it is difficult to see any long-term effects (other than in the upper envelope of data) in Fig. 3b. The lower four panels of Fig. 3 redress this by considering seasonal means, with each data point representing the mean over different 3-month periods. Because of the previously discussed biases in calculated and modelled ozone, all data shown in Fig. 3c–f were normalized. The measured UVI values were normalized to the average of all values, while the calculated UVIs were normalized to the average of only those years with measurements. The normalized peak UVI changes derived from measurements (blue lines) are compared with those calculated from the assimilated ozone dataset (black lines). Also shown in these panels are the corresponding UVI changes that would have occurred according to the World Avoided calculations reported by the GEOS-CCM model (broken red lines) and the NIWA-UKCA model (broken magenta lines). UVI values in the World Expected are also shown (broken green lines). The heavier solid lines for each model run include smoothing with an approximating spline. Both World Avoided datasets and the World Expected dataset were normalized to the average of the calculated UVI values of the years 1978 to 1987; the decade that immediately preceded the signing of the Montreal Protocol. Corresponding plots for all other sites are in Supplementary Data. In the period prior to 2020 shown in Fig. 3, projected changes are generally smaller with the NIWA-UKCA model than with the GEOS-CCM model. However, this is not everywhere the case. At northern mid-latitudes, the two models are in close agreement (see Supplementary Data). They are also similar at high southern latitudes during summer, while the NIWA-UKCA values are larger at high northern latitudes. Reasons for these model differences are outside the scope of the present study. As expected, the World Expected line (green) is usually below the World Avoided line (pink). However, for a short period in the late 1990s, which is most pronounced in the winter, it is higher. Differences of this magnitude are within the range of spread between model runs of about 5%. UVI in summer Possible changes in UV radiation during summer are most relevant from an environmental and health perspective. In Fig. 4, we compare measured, calculated, and projected UVIs for summer at all 17 sites in Table 1. The figure shows that the World Avoided trends depend greatly on latitude and that differences between the two model runs are also latitude-dependent. For example, at latitude 40°N, there is close agreement between the two models (for other seasons, see Supplementary Data). With the exception of Hoher Sonnblick, the measured data from all sites closely match the calculated values and are much closer to the World Expected curves than the World Avoided curves. However, there is a significant divergence between the measured values and World Expected values at higher latitudes: measured and calculated UVI ratios are more or less constant over time while the World Expected curves have a broad maximum during the first decade of the 21st century (last two panels of Fig. 4). This suggests that the impact of the large spring-time ozone depletions persists for too long into the following summer in the model. This is a well-known limitation of CCMs28 for which the causes are not fully understood, and is an area of current research. The measurements at Hoher Sonnblick (Panel f) show a continuation of the previously reported upward trend in summertime UVI30, which was attributed to changes in aerosols or cloud cover. This increase is not present in all seasons, so it is not a calibration artefact. However, there are several seasonal gaps in the data, and the year-to-year variability is also much greater at this mountainous site (see Supplementary Data), possibly due to variable snow cover. At some other sites, the length of the time series is too short for reliable trend estimates. Only nine of the 17 sites have more than 20 years of data coverage. Figure 4 also indicates that UVI ratios calculated from the assimilated ozone data are generally less than unity prior to the 1990s and before the start of UV measurements. The slope in the calculated data is generally consistent with the slope in the datasets of the three CCM models. These model calculations imply that considerable changes in summer UVI occurred between 1978 and 1990 (about 5% at northern mid-latitude sites, up to 10% at southern mid-latitude sites and up to 20% at the three Antarctic sites). However, direct UVI observations needed to confirm these changes do not exist. After accounting for differences in elevation between the sites, we note that latitude-for-latitude, the mean summer UVI values tend to be larger at the southern hemisphere (SH) sites compared with the northern hemisphere (NH) sites, as has been predicted and observed previously31,32,33,34. This NH/SH difference is as expected. For example, Fig. 2 shows that at 45°S, the peak UVI value is larger than at 45°N by approximately 13%. Approximately half of this difference is due to ozone differences and half is due to Sun-Earth separation differences. The much larger NH/SH differences reported in the past31,32,33,34 also include effects of clouds and aerosols, which were not considered in the CCM calculations. The NH/SH asymmetry is projected to be only slightly smaller by year 2100. UVI in spring at high latitudes In Fig. 5, we compare normalized measured, calculated, World Avoided, and World Expected UVIs in spring for the Arctic and Antarctic sites included in this study, where the largest long-term changes in UVI have been observed. Note the expanded vertical axis scale compared with that in Fig. 4. For these high-latitude sites, the “calculated” and “measured” data sets are in almost perfect agreement, particularly in Antarctica, indicating that ozone variation is the largest contributor to UVI changes. Variability of clouds and albedo is a minor contributor in comparison. The “hump” in the World Expected data noted previously for the summer data (Fig. 4), which peaks in the early part of the 21st century, is also present in the spring data (Fig. 5). However, in the spring period, there is also a hint of this in the measured and calculated data for the two Antarctic sites and perhaps also at Summit. Data from Barrow show more variability, as one would expect from an Arctic coastal site that is affected by changes in albedo from snow and sea ice. Decadal trends in UVI Due to the less complete data coverage early in the period, our statistical analysis is restricted to the period since 1996. This period also excludes effects from the eruption of Mt Pinatubo, which led to significant effects on ozone and UV at some locations35,36,37,38. The period since 1996 also includes approximately two complete 11-year solar cycles, which cause variations in ozone of ±2%39,40 that would lead in turn to a modulation of similar relative magnitude, but of opposite sign, in the UVI. Even for the period since 1996, measured data are unfortunately incomplete at some sites, and only a small number of sites have full data coverage through to the end of 2018 (see Table 1). For example, due to funding restrictions, measurements were terminated in 2017 at Arctic sites that were initiated by Biospherical Instruments (BSI). Their time series from Ushuaia and San Diego are also restricted to the period before 2010 and 2008 respectively. There was also a gap from 2003 to 2008 in Melbourne data. Of the 17 sites, only three (Lauder, Palmer, and Thessaloniki) have near-complete data coverage for the full period from 1996 to 2018. However, six others (Barrow, Hoher Sonnblick, Boulder, Mauna Loa, Arrival Heights and South Pole) have only a few years of missing data over that period. Greatest confidence should be placed on data from these nine stations. There are other possible forcing mechanisms that drive interannual variability in UVI. These include variability due to the QBO or the El Nino Southern Oscillation (ENSO). However, over time scales as long as 22 years, any such effects are small, and have not been considered in the statistical analysis. In these seasonal averages, where each data point is separated from the previous value by a period of 9 months, any statistical auto-correlation effects should also be small. In the trend analysis, we have assumed that any long-term changes over the period 1996 to 2018 could be represented by a linear change, which is a reasonable assumption (e.g., see Fig. 4). Results of the statistical analysis are shown in Fig. 6. The results are not particularly sensitive to the start year, resulting in a similar picture (not shown) if the start-date for the analysis is changed by 1 or 2 years. Note that the error bars shown for the trend estimates in Fig. 6 are 2-σ uncertainties of the regression model, which also include small random uncertainties in the measurements that propagate to the 90-day averages analysed here. However, systematic errors due to potential long-term drifts in the measurements (e.g., due to the transfer of irradiance scales between calibration standards) are not included. Figure 6 shows the following: The two World Avoided Simulations give similar trends: With the exception of Palmer Station in winter, there is good agreement between the trends derived from the two World Avoided simulations. (At Palmer Station, the sun is only 2° above the horizon (SZAmin = 88°) at the winter solstice, so peak UVI values during this period are small.) The calculated UVI is also sensitive to small modelling and sampling differences (see Supplementary Data). Also, as shown in Fig. 1 (lower left panel), there are significant differences in the seasonal variability between the two model projections in this latitude region and period. UV Trends are large in the World Avoided Simulations: In the World Avoided (without the Montreal Protocol), UVI levels would have increased over the last 22 years by approximately 50% per decade at high southern latitudes in spring, and by 30% per decade in summer. Increases of up to 20% per decade would have been seen at northern high latitudes. At midlatitudes, the increases would have been approximately 5–10% per decade. Such changes would have been clearly detectable in the measurement data. Measurements Differ from the World Avoided Simulations: In the spring and summer, the observed trends for all nine sites with good data coverage (solid symbols in Fig. 6) are significantly different from the World Avoided trends at all mid- and high-latitudes in the southern hemisphere, and at high latitudes in the northern hemisphere. At northern mid-latitudes, differences between measured trends and trends from the World Avoided simulations are significant in summer at all sites except Hoher Sonnblick, but in other seasons the results are more mixed. Measurements follow the World Expected Simulations: For all sites, trends calculated from the measurements are consistent with the World Expected scenario, though uncertainties are large at Hoher Sonnblick, and other sites (e.g., San Diego, Saint Denis and Obs. Haute-Provence), where there are only a few years of observation. While variability in UVI is close to that predicted by changes in ozone at the southern hemisphere sites, the situation is more complex at northern mid-latitude sites, such as Hoher Sonnblick, where the effects of changes in aerosols and clouds are more important in some seasons. Evidence of a Downward Tendency in UVI since 1996 in the Southern Hemisphere: At the three Antarctic sites (South Pole, Arrival Heights, and Palmer Station) the measured UVIs reveal decreases of about 5% per decade during summer, however, only the trend at Arrival Heights is significant at the 95% confidence level. We note that UVIs calculated from changes in ozone show almost no change, suggesting that changes in albedo or cloud cover contribute to the trends in the measured UVIs. We also note that measurements at these three remote sites are potentially affected by long-term drifts of approximately 1% per decade, which are associated with hardware modifications and changes in calibration standards. Even if these drifts were confirmed, the downward trend at Arrival Heights would remain statistically significant. At the South Pole and Arrival Heights, both measured and calculated UVIs appear to have decreased during spring (the period most affected by the ozone hole), however, trends calculated from these changes are not yet statistically significant. At Lauder, small downward trends in measured UVI are observed for summer and autumn, which are on the verge of being statistically significant. These trends are generally consistent with trends derived from the NIWA/BS ozone dataset, although throughout the southern hemisphere, trends are systematically more negative for measurements than for calculations for all seasons. Where data are available in the early 1990s, most sites show evidence of increasing UVI in the earliest part of the record when ozone was declining. However, the short length of the data record prior to 2000, and possible interference from the eruption of Mt Pinatubo, hinder our ability to ascribe changes in UVI to changes in ozone. In most cases, we find that calculated and measured trends have been small and are in most cases not significantly different from zero. With the exception of one site (Hoher Sonnblick), they also agree with each other to within their error bars, and with trends calculated with the World Expected model. At clean-air sites in the southern hemisphere, the UVI has followed the World Expected scenario within the limits of the measurement uncertainty. Differences between measurements and the two World Avoided models are already highly significant in the Arctic, and at southern hemisphere sites, especially in Antarctica. The situation is more complex at mid-latitudes in the northern hemisphere, where the effects of changes in aerosol and clouds mask effects of ozone. For winter and autumn, changes observed at mid-latitude sites are mixed. Measurements show a tendency towards decreasing UVI in the southern hemisphere and increasing UVI in the northern hemisphere. However, few of the observed long-term changes since 1996 are statistically significant. A statistically significant decrease in measured summertime UVI has been observed at the Antarctic site Arrival Heights, and the reduction in UVI at Lauder is close to being statistically significant at the 95% level. However, at both sites, trends calculated from ozone remain close to zero, showing that the reductions in UVI must be due to other factors (e.g., changes in cloud, aerosol, or surface albedo). Measurements during the last few years at Lauder also show signs of decreases in UVI, which also cannot be attributed to ozone changes. The Montreal Protocol has been effective in curbing increases in harmful UVI. Without the Montreal Protocol, UVI values at northern and southern latitudes <50° would by now be 10 to 20% larger in all seasons compared to UVIs observed during the early 1990s. These changes would have had grave consequences for public health and would have led to increases in skin cancer occurrences41. For latitudes >50°S, UVI values would have increased over the same period between 25% (Ushuaia in summer and autumn) to more than 100% (South Pole in spring and summer). UVI values in the future remain uncertain because of: possible volcanic eruptions, which could temporarily exacerbate ozone depletion as long as chlorine levels remain elevated; interactions with other aspects of climate change, such as changes in clouds and aerosols; effects of increasing greenhouse gases, which will lead to stratospheric cooling and changes in dynamics that may subsequently cause ozone to increase above levels observed in 1980 outside polar regions; non-compliance to the Montreal Protocol, such as found in a recent study44. The reduced number of operational sites measuring UV irradiance is concerning. The value of time series data increases with the length of the record, as shown by the smaller error bars for the longer-term measurement sites in Fig. 6. Unfortunately, there are only a few high-quality NDACC sites with data from the early 1990s that are still operational. It is important that they continue to be supported in case of unexpected future changes. 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An unexpected and persistent increase in global emissions of ozone-depleting CFC-11. Nature 557, 413–417, https://doi.org/10.1038/s41586-018-0106-2 (2018). The number of people involved with maintaining measurements at the various sites is too large for them to be named individually, but we gratefully acknowledge the long-term contribution from Michael Kotkamp from NIWA Lauder, who has been responsible for maintaining data quality and archival of data from all the “NIWA” instrumented sites for more than 25 years. We also thank Dan Smale for generating the 5D TUV lookup tables, and Stefan Seckmeyer for the IDL code to interpolate them. This work was supported by NIWA as part of its government-funded core research. The authors wish to acknowledge the use of New Zealand eScience Infrastructure (NeSI) high performance computing facilities, consulting support and/or training services as part of this research. New Zealand’s national facilities are provided by NeSI and funded jointly by NeSI’s collaborator institutions and through the Ministry of Business, Innovation & Employment’s Research Infrastructure programme. URL https://www.nesi.org.nz. Measurements from the French sites are supported by CNES within the TOSCA program. The authors declare no competing interests. Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. About this article Cite this article McKenzie, R., Bernhard, G., Liley, B. et al. Success of Montreal Protocol Demonstrated by Comparing High-Quality UV Measurements with “World Avoided” Calculations from Two Chemistry-Climate Models. Sci Rep 9, 12332 (2019). https://doi.org/10.1038/s41598-019-48625-z Scientific Reports (2022) Updated analysis of data from Palmer Station, Antarctica (64° S), and San Diego, California (32° N), confirms large effect of the Antarctic ozone hole on UV radiation Photochemical & Photobiological Sciences (2022) Scientific Reports (2021) Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020 Photochemical & Photobiological Sciences (2021)
All High School Physics Resources Example Question #1 : Interpreting Force Diagrams Which of the following represents the force due to friction? The force due to friction will always be parallel to the surface upon which the object is traveling. It will come directly from the center of the object, and be pointed in the opposite direction to the motion of the object. In this diagram, V is pointed parallel to the surface and opposite to the direction of motion. Example Question #2 : Interpreting Force Diagrams Which of the following represents the force due to gravity? Remember, in a force diagram, forces come from the center of the object. The force of gravity will always be straight down from the center of the object. In this diagram, W is pointed directly downward. Example Question #3 : Interpreting Force Diagrams What is the value of angle within the triangle made by X, W, and Y? More information is needed When working in an inclined plane, when we break our force due to gravity into components, the angle at the top that triangle will be equal to the angle of the inclined plane. In the diagram, the total force due to gravity is given by W. X represents the horizontal component, and is parallel to the surface of the plane. Y represents the vertical component, and is perpendicular to the surface of the plane. X and Y thus create a right angle, with W as the hypotenuse. By turning this triangle such that the right angle aligns with the right angle of the inclined plane (between Q and P), we can see that W aligns with the incline surface and Y aligns with the base, P. Based on these alignments, the angle between W and Y must be equal to the angle between the surface and P; thus, . Example Question #4 : Interpreting Force Diagrams Which of the following represents the normal force? The normal force is always perpendicular to the surface on which the object is placed, and is pointed away from said surface. In this diagram, Z is the only force that is perpendicular to the surface and in the upward direction. This force must counteract the vertical force of gravity, which will be perpendicular to the surface in the downward direction (Y). Example Question #5 : Interpreting Force Diagrams Which of the following statements is not true? In this diagram, V represents the force due to friction. The equation for the force due to friction is , where is the coefficient of friction. In this case, Z represents the normal force. We can re-write the equation for friction: Z can be re-written in terms of the angle, but will always need to be multiplied by the coefficient of friction in order to give an equation for V. The other equations are true. - X and Y form a right angle, so the Pythagorean theorem applies. - Z is the normal force, which is, by definition, equal and opposite the vertical force of gravity. - W is the total force of gravity, which will be equal to the mass times the acceleration of gravity. - the triangle formed by W, X, and Y is similar to the triangle formed by the surface, Q, and P, meaning that these angles must be equal. Example Question #6 : Interpreting Force Diagrams According to this force diagram, the normal force will be equal to which of the following? In this problem, Y and Z are equal, but opposite forces, and Z is our normal force. If we can solve for Y, then we can find Z. We can use our understanding of trigonometry to find an equation for Y. If we plug in for the angle, we see: Since we are solving for Y, we can multiply both sides by W. Now that we know an equation for Y, we can return to our original equation to solve for Z. Example Question #7 : Interpreting Force Diagrams What is the distance the object travels based on this diagram? More information is needed More information is needed There is no way for us to know the distance the object travels. Even though the force diagram places our object roughly halfway up the plane, we do not know the position where the object starts or where the object ends. We cannot calculate a change in distance. Example Question #8 : Interpreting Force Diagrams Which of the following correctly calculates X in terms of W? We can use our understanding of trigonometry to find this relationship, since X and Y form a right angle. If we plug in for the angle, we see that X is opposite of and W is the hypotenuse. Since we're looking for X, we can multiply both sides by W. Example Question #9 : Interpreting Force Diagrams How can we use this diagram to help calculate the net force on the object? For this problem, we need to break the forces into horizontal and vertical components. The only difference with an inclined plane is that you have to translate the horizontal plane to be parallel to the surface upon which the object is traveling, and the vertical plane to be perpendicular to the surface upon which the object is traveling. Luckily, this is already done in the diagram, with the force of gravity (W) broken into the vertical component (Y) and horizontal component (X). Now, we need to sum the forces in each plane. The forces in the vertical plane will be perpendicular to the surface: Z and Y. Since Z and Y are opposite and equal forces: There is no net force in the vertical plane. This makes sense, as we would not expect the object to have any movement perpendicular to the surface on which it is sliding. Now we can sum the horizontal forces: V and X. Note that X is positive and V is negative. This is because V represents the force of friction, and is opposite to the force of X. Since there is no force in the vertical plane, this gives our final net force: .
Machine Learning is a multidisciplinary field of study, which gives computers the ability to solve complex problems, which otherwise would be nearly impossible to be hand-coded by a human being. Machine Learning is a scientific field of study which involves the use of algorithms and statistics to perform a given task by relying on inference from data instead of explicit instructions. The process of Machine Learning can be broken down into several parts, most of which is based around “Data”. The following steps show the Machine Learning Process. 1. Gathering Data from various sources: Since Machine Learning is basically the inference drawn from data before any algorithm can be used, data needs to be collected from some source. Data collected can be of any form, viz. Video data, Image data, Audio data, Text data, Statistical data, etc. 2. Cleaning data to have homogeneity: The data that is collected from various sources does not always come in the desired form. More importantly, data contains various irregularities like Missing data and Outliers.These irregularities may cause the Machine Learning Model(s) to perform poorly. Hence, the removal or processing of irregularities is necessary to promote data homogeneity. This step is also known as data pre-processing. 3. Model Building & Selecting the right Machine Learning Model: After the data has been correctly pre-processed, various Machine Learning Algorithms (or Models) are applied on the data to train the model to predict on unseen data, as well as to extract various insights from the data. After various models are “trained” to the data, the best performing model(s) that suit the application and the performance criteria are selected. 4. Getting Insights from the model’s results: Once the model is selected, further data is used to validate the performance and accuracy of the model and get insights as to how the model performs under various conditions. 5. Data Visualization: This is the final step, where the model is used to predict unseen and real-world data. However, these predictions are not directly understandable to the user, and hence, data Visualization or converting the results into understandable visual graphs is necessary. At this stage, the model can be deployed to solve real-world problems. To get the similarities out of the way, both, Machine Learning and Curve Fitting rely on data to infer a model which, ideally, fits the data perfectly. The difference comes in the availability of the data. Let’s initiate the idea of Bias and Variance with a case study. Let’s assume a simple dataset of predicting the price of a house based on its carpet area. Here, the x-axis represents the carpet area of the house, and the y-axis represents the price of the property. The plotted data (in a 2D graph) is shown in the graph below: The goal is to build a model to predict the price of the house, given the carpet area of the property. This is a rather easy problem to solve and can easily be achieved by fitting a curve to the given data points. But, for the time being, let’s concentrate on solving the same using Machine Learning. In order to keep this example simple and concentrate on Bias and Variance, a few assumptions are made: With the above assumptions, the data is processed to train the model using the following steps: 1. Shuffling the data: Since the y-axis data-points are independent of the order of the sequence of the x-axis data-points, the dataset is shuffled in a pseudo-random manner. This is done to avoid unnecessary patterns from being learned by the model. During the shuffling, it is imperative to keep each x-y pair data point constant. Mixing them up will change the dataset itself and the model will learn inaccurate patterns. 2. Data Splitting: The dataset is split into three categories: Training Set (60%), Validation Set (20%), and Testing Set (20%). These three sets are used for different purposes: 3. Model Selection: Several Machine Learning Models are applied to the Training Set and their Training and Validation Losses are determined, which then helps determine the most appropriate model for the given dataset. During this step, we assume that a polynomial equation fits the data correctly. The general equation is given below: The process of “Training” mathematically is nothing more than figuring out the appropriate values for the parameters: a0, a1, ... ,an, which is done automatically by the model using the Training Set. The developer does have control over how high the degree of the polynomial can be. These parameters that can be tuned by the developer are called Hyperparameters. These hyperparameters play a key role in deciding how well would the model learn and how generalized will the learned parameters be. Given below are two graphs representing the prediction of the trained model on training data. The graph on the left represents a linear model with an error of 3.6, and the graph on the right represents a polynomial model with an error of 1.7. By looking at the errors, it can be concluded that the polynomial model performs significantly better when compared to the linear model (Lower the error, better is the performance of the model). However, when we use the same trained models on the Testing Set, the models perform very differently. The graph on the left represents the same linear model’s prediction on the Testing Set, and the graph on the right side represents the Polynomial model’s prediction on the Testing Set. It is clearly visible that the Polynomial model inaccurately predicts the outputs when compared to the Linear model. In terms of error, the total error for the Linear model is 3.6 and for the Polynomial model is a whopping 929.12. Such a big difference in errors between the Training and Testing Set clearly signifies that something is wrong with the Polynomial model. This drastic change in error is due to a phenomenon called Bias-Variance Tradeoff. Error in Machine Learning is the difference in the expected output and the predicted output of the model. It is a measure of how well the model performs over a given set of data. There are several methods to calculate error in Machine Learning. One of the most commonly used terminologies to represent the error is called the Loss/Cost Function. It is also known as the Mean Squared Error (or MSE) and is given by the following equation: The necessity of minimization of Errors: As it is obvious from the previously shown graphs, the higher the error, the worse the model performs. Hence, the error of the prediction of a model can be considered as a performance measure: Lower the error of a model, the better it performs. In addition to that, a model judges its own performance and trains itself based on the error created between its own output and the expected output. The primary target of the model is to minimize the error so as to get the best parameters that would fit the data perfectly. Total Error: The error mentioned above is the Total Error and consists of three types of errors: Bias + Variance + Irreducible Error. Total Error = Bias + Variance + Irreducible Error Even for an ideal model, it is impossible to get rid of all the types of errors. The “irreducible” error rate is caused by the presence of noise in the data and hence is not removable. However, the Bias and Variance errors can be reduced to a minimum and hence, the total error can also be reduced significantly. Ideally, the complete dataset is not used to train the model. The dataset is split into three sets: Training, Validation and Testing Sets. Each of these serves a specific role in the development of a model which performs well under most conditions. Training Set (60-80%): The largest portion of the dataset is used for training the Machine Learning Model. The model extracts the features and learns to recognize the patterns in the dataset. The quality and quantity of the training set determines how well the model is going to perform. Testing Set (15-25%): The main goal of every Machine Learning Engineer is to develop a model which would generalize the best over a given dataset. This is achieved by training the model(s) on a portion of the dataset and testing its performance by applying the trained model on another portion of the same/similar dataset that has not been used during training (Testing Set). This is important since the model might perform too well on the training set, but perform poorly on unseen data, as was the case with the example given above. Testing set is primarily used for model performance evaluation. Validation Set (15-25%): In addition to the above, because of the presence of more than one Machine Learning Algorithm (model), it is often not recommended to test the performance of multiple models on the same dataset and then choose the best one. This process is called Model Selection, and for this, a separate part of the training set is used, which is also known as Validation Set. A validation set behaves similar to a testing set but is primarily used in model selection and not in performance evaluation. Bias is used to allow the Machine Learning Model to learn in a simplified manner. Ideally, the simplest model that is able to learn the entire dataset and predict correctly on it is the best model. Hence, bias is introduced into the model in the view of achieving the simplest model possible. Parameter based learning algorithms usually have high bias and hence are faster to train and easier to understand. However, too much bias causes the model to be oversimplified and hence underfits the data. Hence these models are less flexible and often fail when they are applied on complex problems. Mathematically, it is the difference between the model’s average prediction and the expected value. Variance in data is the variability of the model in a case where different Training Data is used. This would significantly change the estimation of the target function. Statistically, for a given random variable, Variance is the expectation of squared deviation from its mean. In other words, the higher the variance of the model, the more complex the model is and it is able to learn more complex functions. However, if the model is too complex for the given dataset, where a simpler solution is possible, a model with high Variance causes the model to overfit. When the model performs well on the Training Set and fails to perform on the Testing Set, the model is said to have Variance. A biased model will have the following characteristics: A model with high Variance will have the following characteristics: From the understanding of bias and variance individually thus far, it can be concluded that the two are complementary to each other. In other words, if the bias of a model is decreased, the variance of the model automatically increases. The vice-versa is also true, that is if the variance of a model decreases, bias starts to increase. Hence, it can be concluded that it is nearly impossible to have a model with no bias or no variance since decreasing one increases the other. This phenomenon is known as the Bias-Variance Trade In order to get a clear idea about the Bias-Variance Tradeoff, let us consider the bulls-eye diagram. Here, the central red portion of the target can be considered the location where the model correctly predicts the values. As we move away from the central red circle, the error in the prediction starts to increase. Each of the several hits on the target is achieved by repetition of the model building process. Each hit represents the individual realization of the model. As can be seen in the diagram below, the bias and the variance together influence the predictions of the model under different circumstances. Another way of looking at the Bias-Variance Tradeoff graphically is to plot the graphical representation for error, bias, and variance versus the complexity of the model. In the graph shown below, the green dotted line represents variance, the blue dotted line represents bias and the red solid line represents the error in the prediction of the concerned model. The expected values is a vector represented by y. The predicted output of the model is denoted by the vector y for input vector x. The relationship between the predicted values and the inputs can be taken as y = f(x) + e, where e is the normally distributed error given by: The third term in the above equation, irreducible_error represents the noise term and cannot be fundamentally reduced by any given model. If hypothetically, infinite data is available, it is possible to tune the model to reduce the bias and variance terms to zero but is not possible to do so practically. Hence, there is always a tradeoff between the minimization of bias and variance. Detection of Bias and Variance of a model In model building, it is imperative to have the knowledge to detect if the model is suffering from high bias or high variance. The methods to detect high bias and variance is given below: A graphical method to Detect a model suffering from High Bias and Variance is shown below: The graph shows the change in error rate with respect to model complexity for training and validation error. A systematic approach to solve a Bias-Variance Problem by Dr. Andrew Ng: Dr. Andrew Ng proposed a very simple-to-follow step by step architecture to detect and solve a High Bias and High Variance errors in a model. The block diagram is shown below: Detection and Solution to High Bias problem - if the training error is high: Detection and Solution to High Variance problem - if a validation error is high: To summarize, Bias and Variance play a major role in the training process of a model. It is necessary to reduce each of these parameters individually to the minimum possible value. However, it should be kept in mind that an effort to decrease one of these parameters beyond a certain limit increases the probability of the other getting increased. This phenomenon is called as the Bias-Variance Tradeoff and is a parameter to consider during model building. Data Science has become one of the most popular in... Read More
Linear regression is a powerful statistical tool used to model the relationship between a dependent variable and one or more independent variables (features). An important, and often forgotten, concept in regression analysis is that of interaction terms. In short, interaction terms enable you to examine whether the relationship between the target and the independent variable changes depending on the value of another independent variable. Interaction terms are a crucial component of regression analysis, and understanding how they work can help practitioners better train models and interpret their data. Despite their importance, however, interaction terms can be difficult to understand. This post provides an intuitive explanation of interaction terms in the context of linear regression. What are interaction terms in regression models? First, here’s the simpler case; that is, a linear model without interaction terms. Such a model assumes that the effect of each feature or predictor on the dependent variable (target) is independent of other predictors in the model. The following equation describes such a model specification with two features: To make the explanation easier to understand, here’s an example. Imagine that you are interested in modeling the price of real estate properties (y) using two features: their size (X1) and a Boolean flag indicating whether the apartment is located in the city center (X2). is the intercept, and are coefficients of the linear model, and is the error term (unexplained by the model). After gathering data and estimating a linear regression model, you obtain the following coefficients: Knowing the estimated coefficients and that X2 is a Boolean feature, you can write out the two possible scenarios depending on the value of X2. Outside of the city center How to interpret those? While this might not make a lot of sense in the context of real estate, you can say that a 0-square-meter apartment in the city center costs 310 (the value of the intercept). Each square meter of additional space increases the price by 20. In the other case, the only difference is that the intercept is smaller by 10 units. Figure 1 shows the two best-fit lines. As you can see, the lines are parallel and they have the same slope — the coefficient by X1, which is the same in both scenarios. Interaction terms represent joint effects At this point, you might argue that an additional square meter in an apartment in the city center costs more than an additional square meter in an apartment on the outskirts. In other words, there might be a joint effect of these two features on the price of real estate. So, you believe that not only the intercept should be different between the two scenarios but also the slope of the lines. How to do that? That is exactly when the interaction terms come into play. They make the models’ specifications more flexible and enable you to account for such patterns. An interaction term is effectively a multiplication of the two features that you believe have a joint effect on the target. The following equation presents the model’s new specification: Again, assume that you have estimated your model and you know the coefficients. For simplicity, I’ve kept the same values as in the previous example. Bear in mind that in a real-life scenario, they would likely differ. Outside of the city center After you write out the two scenarios for X2 (city center or outside of the city center), you can immediately see that the slope (coefficient by X1) of the two lines is different. As hypothesized, an additional square meter of space in the city center is now more expensive than in the suburbs. Interpreting the coefficients with interaction terms Adding interaction terms to a model changes the interpretation of all the coefficients. Without an interaction term, you interpret the coefficients as the unique effect of a predictor on the dependent variable. So in this case, you could say that was the unique effect of the size of an apartment on its price. However, with an interaction term, the effect of the apartment’s size is different for different values of X2. In other words, the unique effect of apartment size on its price is no longer limited to . To better understand what each coefficient represents, here’s one more look at the raw specification of a linear model with interaction terms. Just as a reminder, X2 is a Boolean feature indicating whether a particular apartment is in the city center. Now, you can interpret each of the coefficients in the following way: - : Intercept for the apartments outside of the city center (or whichever group that had a zero value for the Boolean feature X2). - : Slope (effect of price) for apartments outside of the city center. - : Difference in the intercept between the two groups. - : Difference in slopes between apartments in the city center and outside of it. For example, assume that you are testing a hypothesis that there is an equal impact of the size of an apartment on its price, regardless of whether the apartment is in the city center. Then, you would estimate the linear regression with the interaction term and check whether is significantly different from 0. Some additional notes on the interaction terms: - I’ve presented two-way interaction terms; however, higher-order interactions (for example, of three features) are also possible. - In this example, I showed an interaction of a numerical feature (size of the apartment) with a Boolean one (is the apartment in the city center?). However, you can create interaction terms for two numerical features as well. For example, you might create an interaction term of the size of the apartment with the number of rooms. For more information, see the Related resourcessection. - It might be the case that the interaction term is statistically significant, but the main effects are not. Then, you should follow the hierarchical principle stating that if you include an interaction term in the model, you should also include the main effects, even if their impacts are not statistically significant. Hands-on example in Python After all the theoretical introduction, here’s how to add interaction terms to a linear regression model in Python. As always, start by importing the required libraries. import numpy as npimport pandas as pdimport statsmodels.api as smimport statsmodels.formula.api as smf# plottingimport seaborn as snsimport matplotlib.pyplot as plt# settingsplt.style.use("seaborn-v0_8")sns.set_palette("colorblind")plt.rcParams["figure.figsize"] = (16, 8)%config InlineBackend.figure_format = 'retina' In this example, you estimate linear models using the statsmodels library. For the dataset, use the mtcars dataset. I am quite sure that if you have ever worked with R, you will be already familiar with this dataset. First, load the dataset: mtcars = sm.datasets.get_rdataset("mtcars", "datasets", cache=True)print(mtcars.__doc__) Executing the code example prints a comprehensive description of the dataset. In this post, I only show the relevant parts — an overall description and the definition of the columns: ====== =============== mtcars R Documentation ====== =============== The data was extracted from the 1974 US magazine MotorTrend, and is composed of fuel consumption and 10 aspects of automobile design and performance for 32 automobiles (1973–74 models). Here’s a DataFrame with 32 observations on 11 (numeric) variables: ===== ==== ======================================== [, 1] mpg Miles/(US) gallon [, 2] cyl Number of cylinders [, 3] disp Displacement (cu.in.) [, 4] hp Gross horsepower [, 5] drat Rear axle ratio [, 6] wt Weight (1000 lbs) [, 7] qsec 1/4 mile time [, 8] vs Engine (0 = V-shaped, 1 = straight) [, 9] am Transmission (0 = automatic, 1 = manual) [,10] gear Number of forward gears [,11] carb Number of carburetors ===== ==== ======================================== Then, extract the actual dataset from the loaded object: df = mtcars.datadf.head() \|Mazda RX4 Wag\|\|21.0\|\|6\|\|160\|\|110\|\|3.90\|\|2.875\|\|17.02\|\|0\|\|1\|\|4\|\|4\| \|Hornet 4 Drive\|\|21.4\|\|6\|\|258\|\|110\|\|3.08\|\|3.215\|\|19.44\|\|1\|\|0\|\|3\|\|1\| For this example, assume that you want to investigate the relationship between the miles per gallon ( mpg) and two features: weight ( wt, continuous) and type of transmission ( First, plot the data to get some initial insights: sns.lmplot(x="wt", y="mpg", hue="am", data=df, fit_reg=False)plt.ylabel("Miles per Gallon")plt.xlabel("Vehicle Weight"); Just by eyeballing Figure 2, you can see that the regression lines for the two categories of the am variable will be quite different. For comparison’s sake, start off with a model without interaction terms. model_1 = smf.ols(formula="mpg ~ wt + am", data=df).fit()model_1.summary() The following tables show the results of fitting a linear regression without the interaction term. OLS Regression Results ==============================================================================Dep. Variable: mpg R-squared: 0.753Model: OLS Adj. R-squared: 0.736Method: Least Squares F-statistic: 44.17Date: Sat, 22 Apr 2023 Prob (F-statistic): 1.58e-09Time: 23:15:11 Log-Likelihood: -80.015No. Observations: 32 AIC: 166.0Df Residuals: 29 BIC: 170.4Df Model: 2 Covariance Type: nonrobust ============================================================================== coef std err t P>\|t\| [0.025 0.975]------------------------------------------------------------------------------Intercept 37.3216 3.055 12.218 0.000 31.074 43.569wt -5.3528 0.788 -6.791 0.000 -6.965 -3.741am -0.0236 1.546 -0.015 0.988 -3.185 3.138==============================================================================Omnibus: 3.009 Durbin-Watson: 1.252Prob(Omnibus): 0.222 Jarque-Bera (JB): 2.413Skew: 0.670 Prob(JB): 0.299Kurtosis: 2.881 Cond. No. 21.7============================================================================== From the summary tables, you can see that the coefficient by the am feature is not statistically significant. Using the interpretation of the coefficients you’ve already learned, you can plot the best-fit lines for both classes of the am feature. X = np.linspace(1, 6, num=20)sns.lmplot(x="wt", y="mpg", hue="am", data=df, fit_reg=False)plt.title("Best fit lines for from the model without interactions")plt.ylabel("Miles per Gallon")plt.xlabel("Vehicle Weight")plt.plot(X, 37.3216 - 5.3528 * X, "blue")plt.plot(X, (37.3216 - 0.0236) - 5.3528 * X, "orange"); Figure 3 shows that the lines are almost overlapping, as the coefficient by the am feature is basically zero. Follow up with a second model, this time with an interaction term between the two features. Here’s how to add an interaction term as an additional input in the model_2 = smf.ols(formula="mpg ~ wt + am + wt:am", data=df).fit()model_2.summary() The following summary tables show the results of fitting a linear regression with the interaction term. OLS Regression Results ==============================================================================Dep. Variable: mpg R-squared: 0.833Model: OLS Adj. R-squared: 0.815Method: Least Squares F-statistic: 46.57Date: Mon, 24 Apr 2023 Prob (F-statistic): 5.21e-11Time: 21:45:40 Log-Likelihood: -73.738No. Observations: 32 AIC: 155.5Df Residuals: 28 BIC: 161.3Df Model: 3 Covariance Type: nonrobust =============================================================================== coef std err t P>\|t\| [0.025 0.975]------------------------------------------------------------------------------Intercept 31.4161 3.020 10.402 0.000 25.230 37.602wt -3.7859 0.786 -4.819 0.000 -5.395 -2.177am 14.8784 4.264 3.489 0.002 6.144 23.613wt:am -5.2984 1.445 -3.667 0.001 -8.258 -2.339==============================================================================Omnibus: 3.839 Durbin-Watson: 1.793Prob(Omnibus): 0.147 Jarque-Bera (JB): 3.088Skew: 0.761 Prob(JB): 0.213Kurtosis: 2.963 Cond. No. 40.1============================================================================== Here are two conclusions that you can quickly draw from the summary tables with the interaction term: - All the coefficients, including the interaction term, are statistically significant. - By inspecting the R2 (and its adjusted variant, as you have a different number of features in the models), you can state that the model with the interaction term results in a better fit. Similarly to the previous case, plot the best-fit lines: X = np.linspace(1, 6, num=20)sns.lmplot(x="wt", y="mpg", hue="am", data=df, fit_reg=False)plt.title("Best fit lines for from the model with interactions")plt.ylabel("Miles per Gallon")plt.xlabel("Vehicle Weight")plt.plot(X, 31.4161 - 3.7859 * X, "blue")plt.plot(X, (31.4161 + 14.8784) + (-3.7859 - 5.2984) * X, "orange"); In Figure 4, you can immediately see the difference in the fitted lines, both in terms of the intercept and the slope, for cars with automatic and manual transmissions. Here’s a bonus: You can also add interaction terms using PolynomialFeatures. The transformer offers not only the possibility to add interaction terms of arbitrary order, but it also creates polynomial features (for example, squared values of the available features). For more information, see sklearn.preprocessing.PolynomialFeatures. When working with interaction terms in linear regression, there are a few things to remember: - Interaction terms enable you to examine whether the relationship between the target and a feature changes depending on the value of another feature. - Add interaction terms as a multiplication of the original features. By adding these new variables to the regression model, you can measure the effects of the interaction between them and the target. It is crucial to interpret the coefficients of the interaction terms carefully to understand the direction and the strength of the relationship. - By using interaction terms, you can make the specification of a linear model more flexible (different slopes for different lines), which can result in a better fit to the data and better predictive performance. You can find the code used in this post in my /erykml GitHub repo. As always, any constructive feedback is more than welcome. You can reach out to me on Twitter or in the comments below. How do you explain interaction terms in regression? › Interaction effect means that two or more features/variables combined have a significantly larger effect on a feature as compared to the sum of the individual variables alone. This effect is important to understand in regression as we try to study the effect of several variables on a single response variable.How do you add an interaction term in linear regression? › - Standardize the observations for each variables. - Multiply corresponding standardized values from specific variables to create the interaction terms and then add these new variables to the set of regression data. - Run the regression. - When they have large main effects. ... - When the effect of one changes for various subgroups of the other. ... - When the importance of the interaction has already been proven in previous studies. ... - When you want to explore new hypotheses. A significant interaction effect means that there are significant differences between your groups and over time. In other words, the change in scores over time is different depending on group membership.What are three way interaction terms in regression? › A three way interaction means that the interaction among the two factors (A * B) is different across the levels of the third factor (C). If the interaction of A * B differs a lot among the levels of C then it sounds reasonable that the two way interaction A * B should not appear as significant.How many two way interaction terms can be considered in the linear regression? › We fit a model with the three continuous predictors, or main effects, and their two-way interactions. Because we have three main effects, there are three possible two-way interactions.Can you have two interaction terms in regression? › First, it is possible to have multiple interaction terms in a model. Second, people may ask why you included some interaction terms and not others - you need to have a good answer.What could adding interaction terms in linear regression lead to? › Adding interaction terms to a regression model has real benefits. It greatly expands your understanding of the relationships among the variables in the model. And you can test more specific hypotheses.How do you explain interaction variables? › An interaction variable or interaction feature is a variable constructed from an original set of variables to try to represent either all of the interaction present or some part of it.Should I include interaction terms in regression? › When the effect of one independent variable depends on the level of another independent variable, we have an interaction; and an interaction term should be included in the regression equation. Do interaction terms solve multicollinearity? › Both higher-order terms and interaction terms produce multicollinearity because these terms include the main effects. Centering the variables is a simple way to reduce structural multicollinearity. Centering the variables is also known as standardizing the variables by subtracting the mean.When should you use interaction terms? › Adding an interaction term to a model — estimated using linear regression — becomes necessary when the statistical association between a predictor and an outcome depends on the value/level of another predictor.How to tell if there is a linear relationship between two variables in regression? › The linear relationship between two variables is positive when both increase together; in other words, as values of get larger values of get larger. This is also known as a direct relationship. The linear relationship between two variables is negative when one increases as the other decreases.What p-value is significant for interaction? › The p-value for the test for a significant interaction between factors is 0.562. This p-value is greater than 5% (α), therefore we fail to reject the null hypothesis.How would you most accurately define a statistical interaction? › -My definition of statistical interaction: "Statistical interaction means the effect of one independent variable(s) on the dependent variable depends on the value of another independent variable(s)." Conversely, "Additivity means that the effect of one independent variable(s) on the dependent variable does NOT depend ...What are the 3 models of interaction? › - Gravity model. The level of interaction between two locations is a function of their attributes pondered by their level of separation. ... - Potential model. ... - Retail model. Species interactions within ecological webs include four main types of two-way interactions: mutualism, commensalism, competition, and predation (which includes herbivory and parasitism).What are the three levels of interaction? › Don Norman proposes the emotional system consists of three different, yet interconnected levels, each of which influences our experience of the world in a particular way. The three levels are visceral, behavioral, and reflective.What if the interaction term is not significant? › If the interaction term is not statistically significant, it should be removed from the model and the analysis rerun without the interaction term. Failure to remove an interaction term that was not statistically significant also can lead to an incorrect conclusion (Engqvist, 2005).How many variables is too many linear regression? › Many difficulties tend to arise when there are more than five independent variables in a multiple regression equation. One of the most frequent is the problem that two or more of the independent variables are highly correlated to one another. This is called multicollinearity. What happen if two features correlates in a linear regression? › Multicollinearity occurs when two or more independent variables have a high correlation with one another in a regression model, which makes it difficult to determine the individual effect of each independent variable on the dependent variable.Can you have an interaction without a main effect? › The simple answer is no, you don't always need main effects when there is an interaction. However, the interaction term will not have the same meaning as it would if both main effects were included in the model.Does an interaction term count as a predictor variable? › They are both considered predictor variables. The interaction tells us that the effect of X on Y is different at different values of Z. It also tells us that the effect of Z on Y is different at different values of X. You can interpret it either way.Can two regression lines intersect each other? › The two lines of regression intersect each other at The two lines of regression coincide and both pass through the common point. It is the point of intersection of the two regression lines. This point of intersection gives the value of the mean. interact_plot plots regression lines at user-specified levels of a moderator variable to explore interactions. The plotting is done with ggplot2 rather than base graphics, which some similar functions use.How can you create interaction terms? › A common interaction term is a simple product of the predictors in question. For example, a product interaction between VARX and VARY can be computed and called INTXY with the following command. COMPUTE INTXY = VARX * VARY. The new predictors are then included in a REGRESSION procedure.What are some examples of interaction? › \|Entertainment (together)\|\|Exchanging Letters\| \|Expressing Gratitude\|\|Family Activities\| \|Group Assignments\|\|Helping Others\| A basic assumption of linear regression is that the relationship between the predictors and response variable is linear. When you have an interaction effect, you add the assumption that relationship between your predictor and response is linear regardless of the level of the moderator.When should you avoid linear regression? › To recapitulate, first, the relationship between x and y should be linear. Second, all the observations in a sample must be independent of each other; thus, this method should not be used if the data include more than one observation on any individual.What is the rule of thumb for VIF? › The VIF of an explanatory variable indicates the strength of the linear relationship between the variable and the remaining explanatory variables. A rough rule of thumb is that the VIFs greater than 10 give some cause for concern. When can you safely ignore multicollinearity? › It increases the standard errors of their coefficients, and it may make those coefficients unstable in several ways. But so long as the collinear variables are only used as control variables, and they are not collinear with your variables of interest, there's no problem.Should a VIF value be less than 5? › A VIF less than 5 indicates a low correlation of that predictor with other predictors. A value between 5 and 10 indicates a moderate correlation, while VIF values larger than 10 are a sign for high, not tolerable correlation of model predictors (James et al.How do you describe the interaction effect? › What are Interaction Effects? An interaction effect occurs when the effect of one variable depends on the value of another variable. Interaction effects are common in regression models, ANOVA, and designed experiments.How would you explain interaction? › Interaction is simply defined as the interacting components communicating with each other. It is a necessary activity to ensure learning in learning environments.How do you describe an interaction? › Interaction comes from Latin inter meaning "between," and ago meaning "to do" or "to act" — any “action between” is considered an interaction, like the interaction between a teacher and a student, two countries, or even baking soda and vinegar (boom!).
O-Levels Math: How to Complete the Square Easily? Completing the square of a quadratic equation is a very useful technique that is used for solving quadratic equations(E-Math), finding the turning point of a quadratic graph (E-Math) and finding the center of a circles equation (A-Math). However, students often forget the method and ask me frequently during our math tuition classes. In this article, I will try to make the process of completing the square as simple and digestible as possible, but I will not further elaborate on the background reasoning behind it. Fundamental Step of Completing Square The key thing to completing the square is to remember this: Formulas can be difficult to appreciate without the help of numbers. Observe the pattern in the following examples of completing the square to understand the above formula: To remember a formula, you have to practice! Completing the Square for a Typical Quadratic Equation After learning the core step in completing the square, we will have to apply it on a typical quadratic equation which has 3 terms. We complete the square the same way as the above section and we simply carry the x-independent term along. Observe the pattern in the following examples of completing the square: *Note that only the crucial step has been shown above. Please further simplify the equation by yourself. Time to test your understanding through practice! Completing the Square of more Complex Quadratic Equations In the previous parts, all the equations start with x^2. So how to we complete the square for equations where the x^2 has a different coefficient? For example, how do we complete the square of Now you have understood the art of completing the square! It is actually a very simple concept and yet students forget it again and again. Just make sure you remember the core formula above and you practice enough! "Don't practice until you get it right, practice until you can't get it wrong!" To get professional help (Math tuition) on secondary school mathematics in Singapore, click here.
logging in or signing up Kepler’s Law of Planetary Motion warrenko Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Copy Does not support media & animations WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 2311 Category: Science & Tech.. License: All Rights Reserved Like it (1) Dislike it (0) Added: October 17, 2010 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: brijesh.k51 (28 month(s) ago) how can i download this Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Kepler’s Law of Planetary Motion : Kepler’s Law of Planetary Motion History of the Laws : History of the Laws Johannes Kepler was a German astronomer and mathematician of the late sixteenth and early seventeenth centuries. His work was largely based on the work of his mentor, Tycho Brahe. Kepler was able to use Bahe's precise measurements (made before telescopes) to determine, mostly by trial and error, three laws that described the motion of the five planets then known. First Law: Kepler's Elliptical Orbit Law: Each planet moves in an elliptical orbit, with the sun at one focus of the ellipse. Second Law: Kepler's Equal-Area Law: A line from the sun to each planet sweeps out equal areas in equal time. The picture to the right depicts this law. Third Law: Kepler's Law of Periods: The periods of the planets (T) are proportional to the 3/2 powers of the major axis lengths of their orbits (L). Expressed mathematically, then, this says that: T is proportional to L3/2 or T2 is proportional to L3 Mathematics of the First Law : Mathematics of the First Law Symbolically: where (r, θ) are heliocentric polar coordinates for the planet, p is the semi-latus rectum, and ε is the eccentricity. Slide 4: At θ = 0°, perihelion, the distance is minimum At θ = 90°, the distance is P. Slide 5: At θ = 180°, aphelion, the distance is maximum Slide 6: The semi-major axis a is the arithmetic mean between rmin and rmax: So Slide 7: The semi-minor axis b is the geometric mean between rmin and rmax: So Slide 8: The semi-latus rectum p is the harmonic mean between rmin and rmax: The eccentricity ε is the coefficient of variation between rmin and rmax: The area of the ellipse is The special case of a circle is ε = 0, resulting in r = p = rmin = rmax = a = b and A = π r2. Slide 9: Aphelion -- the point on its orbit when the Earth is farthest from the sun. Perihelion -- the point on its orbit when the Earth is closest to the sun. Slide 10: The Ellipse in Polar Coordinates Again, if all the values of (r,f) of a curve are related by some equation which can be symbolically written r = r(f) then the function r(f) is said to be the equation of the line, in polar coordinates. The simplest function is a constant number a, giving the line r = a The value of r equals a for any value of f. That gives a circle around the origin, its radius equal to a, shown in the drawing on the right above. The Ellipse Consider next the curve whose equation is r = a(1– e2)/(1+ e cos f) where the eccentricity e is a number between 0 and 1. If e = 0, this is clearly the circle encountered earlier. Slide 11: Kepler's First Law: The orbits of the planets are ellipses, with the Sun at one focus of the ellipse. Kepler's First Law is illustrated in the image shown above. The Sun is not at the center of the ellipse, but is instead at one focus (generally there is nothing at the other focus of the ellipse). The planet then follows the ellipse in its orbit, which means that the Earth-Sun distance is constantly changing as the planet goes around its orbit. For purpose of illustration we have shown the orbit as rather eccentric; remember that the actual orbits are much less eccentric than this. You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
This preview shows pages 1–3. Sign up to view the full content. This preview has intentionally blurred sections. Sign up to view the full version.View Full Document Unformatted text preview: Chapter 5 Divide and Conquer Divide-and-conquer refers to a class of algorithmic techniques in which one breaks the input into several parts, solves the problem in each part recursively, and then combines the solutions to these sub-problems into an overall solution. In many cases, it can be a simple and powerful method. Analyzing the running time of a divide-and-conquer algorithm generally involves solving a recurrence relation that bounds the running time recursively in terms of the running time on smaller instances. We begin the chapter with a general discussion of recurrence relations, illustrating how they arise in the analysis and describing methods for working out upper bounds from them. We then illustrate the use of divide-and-conquer with applications to a number of different domains: computing a distance function on different rankings of a set of objects; finding the closest pair of points in the plane; multiplying two integers; and smoothing a noisy signal. Divide-and-conquer will also come up in subsequent chapters, since it is a method that often works well when combined with other algorithm design techniques; for example, we will see it combined with dynamic programming to produce a space-eﬃcient solution to sequence alignment, and combined with randomization to yield a simple and eﬃcient algorithm for computing the median of a set of numbers. One thing to note about many settings in which divide-and-conquer is applied, including these, is that the natural brute-force algorithm may already be polynomial-time, and the divide-and-conquer strategy is serving to reduce the running time to a lower polynomial. This is in contrast to most of the problems in the previous chapter, for example, where brute-force was exponential and the goal in designing a more sophisticated algorithm was to achieve any kind of polynomial running time. For example, we discussed in Chapter 2 that the natural brute-force algorithm for finding the closest pair among n points in the plane would simply measure all Θ( n 2 ) distances, for a (polynomial) running time of Θ( n 2 ). Using divide-and-conquer, we will improve the running time to O ( n log n ). At a high level, then, the overall theme of this chapter is the same as what we’ve been seeing earlier: that 197 198 CHAPTER 5. DIVIDE AND CONQUER improving on brute-force search is a fundamental conceptual hurdle in solving a problem eﬃciently, and the design of sophisticated algorithms can achieve this. The difference is simply that the distinction between brute-force search and an improved solution here will not always be the distinction between exponential and polynomial. 5.1 A First Recurrence: The Mergesort Algorithm To motivate the general approach to analyzing divide-and-conquer algorithms, we begin with the Mergesort algorithm. We discussed the Mergesort algorithm brieﬂy in Chapter 2, when we surveyed common running times for algorithms. Mergesort sorts a given list of numbers by first dividing them into two equal halves, sorting each half separately by recursion, and... View Full Document This note was uploaded on 02/18/2010 for the course CSB 1208204834 taught by Professor N/a during the Spring '10 term at École Normale Supérieure. - Spring '10
This page uses content from Wikipedia and is licensed under CC BY-SA. The World Geodetic System (WGS) is a standard for use in cartography, geodesy, and satellite navigation including GPS. It comprises a standard coordinate system for the Earth, a standard spheroidal reference surface (the datum or reference ellipsoid) for raw altitude data, and a gravitational equipotential surface (the geoid) that defines the nominal sea level. The latest revision is WGS 84 (also known as WGS 1984, EPSG:4326), established in 1984 and last revised in 2004. Earlier schemes included WGS 72, WGS 66, and WGS 60. WGS 84 is the reference coordinate system used by the Global Positioning System. The WGS 84 datum surface is an oblate spheroid with equatorial radius a = 6378137 m at the equator and flattening f = 1/298.257223563. The polar semi-minor axis b then equals a × (1 − f) = 6356752.3142 m. Currently, WGS 84 uses the Earth Gravitational Model 1996 (EGM96) geoid, revised in 2004. This geoid defines the nominal sea level surface by means of a spherical harmonics series of degree 360 (which provides about 100 km latitudinal resolution near the Equator). The deviations of the EGM96 geoid from the WGS 84 reference ellipsoid range from about −105 m to about +85 m. EGM96 differs from the original WGS 84 geoid, referred to as EGM84. Efforts to supplement the various national surveying systems began in the 19th century with F.R. Helmert's famous book Mathematische und Physikalische Theorien der Physikalischen Geodäsie (Mathematical and Physical Theories of Physical Geodesy). Austria and Germany founded the Zentralbüro für die Internationale Erdmessung (Central Bureau of International Geodesy), and a series of global ellipsoids of the Earth were derived (e.g., Helmert 1906, Hayford 1910/ 1924). A unified geodetic system for the whole world became essential in the 1950s for several reasons: In the late 1950s, the United States Department of Defense, together with scientists of other institutions and countries, began to develop the needed world system to which geodetic data could be referred and compatibility established between the coordinates of widely separated sites of interest. Efforts of the U.S. Army, Navy and Air Force were combined leading to the DoD World Geodetic System 1960 (WGS 60). The term datum as used here refers to a smooth surface somewhat arbitrarily defined as zero elevation, consistent with a set of surveyor's measures of distances between various stations, and differences in elevation, all reduced to a grid of latitudes, longitudes, and elevations. Heritage surveying methods found elevation differences from a local horizontal determined by the spirit level, plumb line, or an equivalent device that depends on the local gravity field (see physical geodesy). As a result, the elevations in the data are referenced to the geoid, a surface that is not readily found using satellite geodesy. The latter observational method is more suitable for global mapping. Therefore, a motivation, and a substantial problem in the WGS and similar work is to patch together data that were not only made separately, for different regions, but to re-reference the elevations to an ellipsoid model rather than to the geoid. In accomplishing WGS 60, a combination of available surface gravity data, astro-geodetic data and results from HIRAN and Canadian SHORAN surveys were used to define a best-fitting ellipsoid and an earth-centered orientation for each of initially selected datum. (Every datum is relatively oriented with respect to different portions of the geoid by the astro-geodetic methods already described.) The sole contribution of satellite data to the development of WGS 60 was a value for the ellipsoid flattening which was obtained from the nodal motion of a satellite. Prior to WGS 60, the U.S. Army and U.S. Air Force had each developed a world system by using different approaches to the gravimetric datum orientation method. To determine their gravimetric orientation parameters, the Air Force used the mean of the differences between the gravimetric and astro-geodetic deflections and geoid heights (undulations) at specifically selected stations in the areas of the major datums. The Army performed an adjustment to minimize the difference between astro-geodetic and gravimetric geoids. By matching the relative astro-geodetic geoids of the selected datums with an earth-centered gravimetric geoid, the selected datums were reduced to an earth-centered orientation. Since the Army and Air Force systems agreed remarkably well for the NAD, ED and TD areas, they were consolidated and became WGS 60. Improvements to the global system included the Astrogeoid of Irene Fischer and the astronautic Mercury datum. In January 1966, a World Geodetic System Committee composed of representatives from the United States Army, Navy and Air Force was charged with developing an improved WGS, needed to satisfy mapping, charting and geodetic requirements. Additional surface gravity observations, results from the extension of triangulation and trilateration networks, and large amounts of Doppler and optical satellite data had become available since the development of WGS 60. Using the additional data and improved techniques, WGS 66 was produced which served DoD needs for about five years after its implementation in 1967. The defining parameters of the WGS 66 Ellipsoid were the flattening (1/298.25 determined from satellite data) and the semimajor axis (6,378,145 meters determined from a combination of Doppler satellite and astro-geodetic data). A worldwide 5° × 5° mean free air gravity anomaly field provided the basic data for producing the WGS 66 gravimetric geoid. Also, a geoid referenced to the WGS 66 Ellipsoid was derived from available astrogeodetic data to provide a detailed representation of limited land areas. After an extensive effort over a period of approximately three years, the Department of Defense World Geodetic System 1972 was completed. Selected satellite, surface gravity and astrogeodetic data available through 1972 from both DoD and non-DoD sources were used in a Unified WGS Solution (a large scale least squares adjustment). The results of the adjustment consisted of corrections to initial station coordinates and coefficients of the gravitational field. The largest collection of data ever used for WGS purposes was assembled, processed and applied in the development of WGS 72. Both optical and electronic satellite data were used. The electronic satellite data consisted, in part, of Doppler data provided by the U.S. Navy and cooperating non-DoD satellite tracking stations established in support of the Navy's Navigational Satellite System (NNSS). Doppler data was also available from the numerous sites established by GEOCEIVERS during 1971 and 1972. Doppler data was the primary data source for WGS 72 (see image). Additional electronic satellite data was provided by the SECOR (Sequential Collation of Range) Equatorial Network completed by the U.S. Army in 1970. Optical satellite data from the Worldwide Geometric Satellite Triangulation Program was provided by the BC-4 camera system (see image). Data from the Smithsonian Astrophysical Observatory was also used which included camera (Baker–Nunn) and some laser ranging. The surface gravity field used in the Unified WGS Solution consisted of a set of 410 10° × 10° equal area mean free air gravity anomalies determined solely from terrestrial data. This gravity field includes mean anomaly values compiled directly from observed gravity data wherever the latter was available in sufficient quantity. The value for areas of sparse or no observational data were developed from geophysically compatible gravity approximations using gravity-geophysical correlation techniques. Approximately 45 percent of the 410 mean free air gravity anomaly values were determined directly from observed gravity data. The astrogeodetic data in its basic form consists of deflection of the vertical components referred to the various national geodetic datums. These deflection values were integrated into astrogeodetic geoid charts referred to these national datums. The geoid heights contributed to the Unified WGS Solution by providing additional and more detailed data for land areas. Conventional ground survey data was included in the solution to enforce a consistent adjustment of the coordinates of neighboring observation sites of the BC-4, SECOR, Doppler and Baker–Nunn systems. Also, eight geodimeter long line precise traverses were included for the purpose of controlling the scale of the solution. The Unified WGS Solution, as stated above, was a solution for geodetic positions and associated parameters of the gravitational field based on an optimum combination of available data. The WGS 72 ellipsoid parameters, datum shifts and other associated constants were derived separately. For the unified solution, a normal equation matrix was formed based on each of the mentioned data sets. Then, the individual normal equation matrices were combined and the resultant matrix solved to obtain the positions and the parameters. The value for the semimajor axis (a) of the WGS 72 Ellipsoid is 6 378 135 meters. The adoption of an a-value 10 meters smaller than that for the WGS 66 Ellipsoid was based on several calculations and indicators including a combination of satellite and surface gravity data for position and gravitational field determinations. Sets of satellite derived station coordinates and gravimetric deflection of the vertical and geoid height data were used to determine local-to-geocentric datum shifts, datum rotation parameters, a datum scale parameter and a value for the semimajor axis of the WGS Ellipsoid. Eight solutions were made with the various sets of input data, both from an investigative point of view and also because of the limited number of unknowns which could be solved for in any individual solution due to computer limitations. Selected Doppler satellite tracking and astro-geodetic datum orientation stations were included in the various solutions. Based on these results and other related studies accomplished by the Committee, an a-value of 6 378 135 meters and a flattening of 1/298.26 were adopted. In the development of local-to WGS 72 datum shifts, results from different geodetic disciplines were investigated, analyzed and compared. Those shifts adopted were based primarily on a large number of Doppler TRANET and GEOCEIVER station coordinates which were available worldwide. These coordinates had been determined using the Doppler point positioning method. In the early 1980s the need for a new world geodetic system was generally recognized by the geodetic community and also within the US Department of Defense. WGS 72 no longer provided sufficient data, information, geographic coverage, or product accuracy for all then-current and anticipated applications. The means for producing a new WGS were available in the form of improved data, increased data coverage, new data types and improved techniques. GRS 80 parameters together with available Doppler, satellite laser ranging and Very Long Baseline Interferometry (VLBI) observations constituted significant new information. An outstanding new source of data had become available from satellite radar altimetry. Also available was an advanced least squares method called collocation which allowed for a consistent combination solution from different types of measurements all relative to the Earth's gravity field, i.e. geoid, gravity anomalies, deflections, dynamic Doppler, etc. The new World Geodetic System was called WGS 84. It is the reference system used by the Global Positioning System. It is geocentric and globally consistent within ±1 m. Current geodetic realizations of the geocentric reference system family International Terrestrial Reference System (ITRS) maintained by the IERS are geocentric, and internally consistent, at the few-cm level, while still being metre-level consistent with WGS 84. The WGS 84 originally used the GRS 80 reference ellipsoid, but has undergone some minor refinements in later editions since its initial publication. Most of these refinements are important for high-precision orbital calculations for satellites but have little practical effect on typical topographical uses. The following table lists the primary ellipsoid parameters. \|Ellipsoid reference\|\|Semi-major axis a\|\|Semi-minor axis b\|\|Inverse flattening (1/f)\| \|GRS 80\|\|6 378 137.0 m\|\|≈ 6 356 752.314 140 m\|\|298.257 222 100 882 711...\| \|WGS 84\|\|6 378 137.0 m\|\|≈ 6 356 752.314 245 m\|\|298.257 223 563\| The very small difference in the flattening thus results in a tiny difference of 0.105 mm in the semi polar axis. The latest major revision of WGS 84 is also referred to as "Earth Gravitational Model 1996" (EGM96), first published in 1996, with revisions as recent as 2004. This model has the same reference ellipsoid as WGS 84, but has a higher-fidelity geoid (roughly 100 km resolution versus 200 km for the original WGS 84). Many of the original authors of WGS 84 contributed to a new higher-fidelity model, called EGM2008. This new model will have a geoid with accuracy approaching 10 cm, requiring over 4.6 million terms in the spherical expansion (versus 130,317 in EGM96 and 32,757 in WGS 84).
A Positive SpinFebruary 22nd, 2006 in Physics / Beams with polarized particles greatly boost the physics output of high energy physics colliders. While it has been straightforward to make polarized electron beams, polarizing positrons is more difficult, especially in the case of linear colliders. The E-166 experiment has successfully demonstrated a technology to make a polarized beam of positrons for a future linear collider. For decades, Stanford Linear Accelerator Center (SLAC) has been making positrons—the antimatter equivalent of electrons—but this is the first polarized positron beam at SLAC. Polarized means the particles are oriented to spin in the same direction; imagine most of the golf balls at a driving range rotating clockwise as they fly toward the net. Beams never reach 100 percent polarization, but the more polarized the beams, the more information they reveal in collisions. E-166 proves that the proposed International Linear Collider (ILC) could be designed with a polarized positron beam. The collaboration is still analyzing the results to determine the precise amount of polarization achieved. “Let’s say the beam is definitely polarized, sufficient for a linear collider,” said Bill Bugg (University of Tennessee, Knoxville). In two runs during June and September 2005, the collaboration used SLAC’s two-mile linac to deliver electrons to the Final Focus Test Beam (FFTB). There the electrons travel through a helical undulator, a one-meter-long magnet that forces the electrons to spiral, thus emitting polarized gamma rays. The gamma rays strike a tungsten target, producing showers of polarized positrons with an average energy of 5 to 6 million electron volts (MeV). Alexander Mikhailichenko (Cornell), who built the undulator for the experiment, was one of the people to originally propose the technique in 1979. The electrons travel through the undulator in a tiny beam pipe—a stainless steel tube with a 0.9-millimeter inside diameter. The pipe is cut from the same hollow metal used for hypodermic needles and cheap, too, at $1 per foot. Even though the electron beam is 20 times narrower than the pipe aperture, some feared the small pipe would be a showstopper. The beam needed to go cleanly through the undulator without touching the pipe wall. Any beam loss at all would have saturated the detectors with background noise. “The undulator performance was superb, like flipping a switch,” said experiment spokesman John Sheppard (ILC). The results put to rest doubts that helical undulators would produce circularly polarized gamma rays or that polarized gamma rays would in turn produce polarized positrons. “SLAC was the only place we could possibly do this experiment,” Sheppard said. “We needed a 50 GeV low-emittance (transversely small) beam, small enough to fit through the undulator beam pipe. The success of the experiment in large part was due to the excellent beam quality and stability delivered by the SLAC operations staff.” Collaborators who took shifts at SLAC came from the University of Tennessee, DESY Hamburg, DESY Zeuthen, Humboldt University Berlin, Cornell, Daresbury, RWTH Aachen, Princeton and Tel-Aviv University. Source: Stanford Linear Accelerator Center (Heather Rock Woods) "A Positive Spin." February 22nd, 2006. http://phys.org/news11113.html
Elementary Statistics (4-0) 4 Cr. Hrs. This course includes an introduction to statistics, statistical descriptions, frequency distributions, possibilities and probabilities, probability distributions, sampling and sampling distributions, testing hypotheses based on measurements, count data, paired data and use of nonparametric tests. (A requirement that must be completed before taking this course.) - MATH 113 with a minimum grade of 2.0 or minimum placement test score of 23 ACT, 29 SAT or 63 CPT (College-Level Math). Upon successful completion of the course, the student should be able to: - Create visual presentations using sample data both by hand and by using statistical software, including a tabular frequency distribution, stem-and-leaf plot, histogram, frequency polygon and pie chart. - Compute descriptive statistics both by using an algorithm and by using statistical software, including the mean, median, mode, fractiles, range, variance and standard deviation. - Determine whether a given sampling method yields a random sample, simple random sample, stratified sample, etc. - Use a random number generator to select a random sample from a given population. - Determine the number of possible outcomes of an event with the aid of the addition, multiplication, complement, factorial and other rules. - Calculate probability of an event by using the classical approach. - Estimate the probability of an event by using the relative frequency approach. - Determine the conditional probability of one event given another event by using the defining formula for conditional probability. - Determine probabilities for various discrete distributions (including the uniform, binomial and hypergeometric) by all of the following means: a formula, a table and statistical software. - Determine probabilities for various continuous distributions (including the Gaussian normal and Student's t) by using a formula and either a table or statistical software. - Interpret probabilities of a discrete random variable as the area of bars in its histogram. - Interpret probabilities of a continuous random variable as the area under the graph of its density function. - Solve practical problems involving probability distributions. - Determine the mean (expected) value and the standard deviation of a discrete random variable using its probability distribution. - Determine whether two events are independent of one another by using their probabilities. - Determine a confidence interval for a population mean, based on a random sample and the normal or t-distribution (as appropriate), both by using a formula and table and by using statistical software. - Test a hypothesis regarding one, two or several population means, based on random sample(s) and the normal, t- or ANOVA distribution (as appropriate), both by using a formula and table and by using statistical software. - Determine a confidence interval for a population proportion, based on a random sample and the normal distribution, both by using a formula and table and by using statistical software. - Test a hypothesis regarding one, two or several population proportions, based on a random sample(s) and the normal, t or chi-squared distribution (as appropriate), both by using a formula and table and by using statistical software. - Determine Pearson's linear correlation coefficient r for a sample of bivariate data, both by using a formula and by using statistical software. - Determine the least-squares linear regression fit to a sample bivariate data. - Test a hypothesis regarding the linear correlation between two variables, based on a random sample and on critical values of the r-distribution, both with the aid of a table and the aid of statistical software. - Test a hypothesis regarding one or two population medians or a population proportion, based on a random sample(s) and the sign test. - Test a hypothesis regarding the linear correlation between two variables, based on a random sample and Spearman's rank-correlation test. \| \|\|122\|\|142701\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|28/31/0\|\|Open\|\| \| \|\|122\|\|142782\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|31/31/0\|\|Open\|\| \| \|\|122\|\|142722\|\|Elementary Statistics \|\|Online\|\|4\|\|Choraszewski L\|\|$12.00\|\|20/31/0\|\|Open\|\| \| \|\|122\|\|142772\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|28/31/0\|\|Open\|\| \| \|\|122\|\|143035\|\|Elementary Statistics\|\| \|\|4\|\|Jankoviak Anderson K\|\|$12.00\|\|26/31/0\|\|Open\|\| \|M W \|\|08:00AM-09:54AM\|\|BTC100\| \| \|\|122\|\|143046\|\|Elementary Statistics\|\| \|\|4\|\|Schwartz R\|\|$12.00\|\|25/31/0\|\|Open\|\| \|T R \|\|10:00AM-11:54AM\|\|BTC165\| \| \|\|122\|\|143061\|\|Elementary Statistics\|\| \|\|4\|\|Marilley D\|\|$12.00\|\|29/31/0\|\|Open\|\| \|T R \|\|07:00PM-08:54PM\|\|BTC170\| \| \|\|122\|\|143068\|\|Elementary Statistics\|\| \|\|4\|\|Marilley D\|\|$12.00\|\|30/31/0\|\|Open\|\| \|M W \|\|06:30PM-08:24PM\|\|BTC165\| \| \|\|122\|\|123023\|\|Elementary Statistics\|\| \|\|4\|\|Gerich R\|\|$12.00\|\|24/31/0\|\|Open\|\| \|M T W R \|\|11:30AM-01:37PM\|\|BTC160\| \| \|\|122\|\|123055\|\|Elementary Statistics\|\| \|\|4\|\|Gerich R\|\|$12.00\|\|23/31/0\|\|Open\|\| \|M T W R \|\|07:00PM-09:07PM\|\|BTC165\| \| \|\|122\|\|122722\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|12/31/0\|\|Open\|\| \| \|\|122\|\|122724\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|26/31/0\|\|Open\|\| \| \|\|122\|\|122735\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|27/31/0\|\|Open\|\| \| \|\|122\|\|133062\|\|Elementary Statistics\|\| \|\|4\|\|Marilley D\|\|$12.00\|\|24/31/0\|\|Open\|\| \|M T W R \|\|07:00PM-09:07PM\|\|BTC320\| \| \|\|122\|\|112724\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|11/31/0\|\|Open\|\| \| \|\|122\|\|112784\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|10/31/0\|\|Open\|\| \| \|\|122\|\|112787\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|8/31/0\|\|Open\|\| \| \|\|122\|\|112789\|\|Elementary Statistics \|\|Online\|\|4\|\|Choraszewski L\|\|$12.00\|\|0/20/1\|\|Closed\|\| \| \|\|122\|\|113021\|\|Elementary Statistics\|\| \|\|4\|\|Benefiel J\|\|$12.00\|\|4/31/0\|\|Open\|\| \|M W \|\|05:00PM-07:26PM\|\|BTC300\| \| \|\|122\|\|112734\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|7/31/0\|\|Open\|\| \| \|\|122\|\|112744\|\|Elementary Statistics \|\|Online\|\|4\|\|Stetson B\|\|$12.00\|\|13/31/0\|\|Open\|\| \| \|\|122\|\|113035\|\|Elementary Statistics\|\| \|\|4\|\|Schwartz R\|\|$12.00\|\|7/31/0\|\|Open\|\| \|T R \|\|10:00AM-11:54AM\|\|BTC165\| \| \|\|122\|\|113049\|\|Elementary Statistics\|\| \|\|4\|\|Marilley D\|\|$12.00\|\|8/31/0\|\|Open\|\| \|M W \|\|04:00PM-05:54PM\|\|BTC165\| \| \|\|122\|\|113070\|\|Elementary Statistics\|\| \|\|4\|\|Marilley D\|\|$12.00\|\|8/31/0\|\|Open\|\| \|M W \|\|07:30PM-09:24PM\|\|BTC320\| \| \|\|122\|\|113075\|\|Elementary Statistics\|\| \|\|4\|\|Gerich R\|\|$12.00\|\|5/31/0\|\|Open\|\| \|T R \|\|06:00PM-07:54PM\|\|BTC100\| \| \|\|122\|\|113130\|\|Elementary Statistics\|\| \|\|4\|\|Jankoviak Anderson K\|\|$12.00\|\|6/31/0\|\|Open\|\| \|M W \|\|09:00AM-10:54AM\|\|BTC320\| Note: This schedule updates once every 24 hours. 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Understanding meaning of the mathematical expressions \|Home / Education\|\|Print Recommend us\| When solving mathematical problems, it is essential to know the meaning of the expressions you see on a test or a homework problem. If you don’t understand the meaning of the expression, you won’t be able to correctly do the problem. This post covers meaning behind equality and the four basic mathematical expressions: addition, subtraction, multiplication, and division. This is about having equal or same parts. An equal symbol (=) is used to indicate equality, in mathematics. Following are some of the mathematical expression meaning equality: - x is equal to y - x is equivalent to y - x is the same y Each of these expressions means both x and y are equal or equivalent. In mathematics, when we are talking about adding, we are talking about increasing. Increasing what and why how much is indicated in the problem. Observe the following expressions: - total of x and y - sum of x and y - x added to y - x increased by y These mathematical expressions mean add x to y or x + y. A plus sign (+) indicates an addition operation. In mathematics, subtraction is about reducing or making less. Again, as for addition, what you are reducing and by how much are dependent on the mathematical problem. The following are some of the mathematical expressions you may encounter while working with subtractions: - x less y - x minus y - the difference between x and y - from x subtract y - x decreased by y - x diminished by y These mathematical expressions mean subtract y from x or x - y. A sign indicating subtraction is -. With multiplication in general the result is increased, just with addition. The result depends on what your mathematical expression. Here are mathematical expressions that all mean the same: - x multiplied by y - the product of x and y In each of the above expressions, the meaning is that we want to multiply x by y, or x * y. * or X indicate multiplication. Division is similar to a subtraction operation in the sense that they both in general produce a lower (not the lowest!) resulting value than the numbers used for the carrying out the operations. 12 - 4 = 8 and 12 / 4 =3 is a good example of this statement. Here are some expressions indicating division operations: - x divided by y - the quotient of x and y ÷ and / indicate division. Laugh a little with these jokes 1. Why do people work seven-days a week? So they don't have to retrain themselves on Monday. 2. A husband points to a marriage counselor that his wife fluently speaks two languages but she cannot keep her mouth shut in one. 3. A husband says to his wife: I know what makes you so smart. She says tell me. The husband says: lack of thinking. Rate this post As part of ongoing efforts to improve this blog, please consider rating this page. Please tell us and other readers about the overall usefulness of this page to you. Please note multiple rating attempts for the same page are not permitted. Only one rating is allowed per visitor per page. Also worth exploring on GiantPile Random educational tips 1. When making a decision on choosing a college, don't ignore the school location. Is the college situated convenient to major transportation or walking distance? Do you enjoy outdoors? Do you want to spend your college years in a city or do you prefer open space? How about the climate? If you love skiing, your preferred choice may not be to select a college under year-round sun-shine. Thinking of how you have grown up may help you decide choosing the college location. 2. Reading. Chances are you will be doing this a lot in college for almost all classes. So it makes sense to have effective reading skills. Use these techniques as a aid: read in a comfortable and quite environment, choose a place to read where you will be able to fully concentrate on your reading, take notes as you read, highlight important points as you read, write outside of the book if you are afraid of loosing resale value of the book, and use breaks between readings.
Gender equality, also known as sex equality, gender egalitarianism, sexual equality, or equality of the genders, is the belief that everyone should receive equal treatment and not be discriminated against based on their gender. Gender equality is one of the objectives of the United Nations Universal Declaration of Human Rights. They seek to create equality in law and in social situations, such as in democratic activities and securing equal pay for equal work. The objective of gender equality is for people of different genders to acquire, if they so choose, equal treatment throughout a society, not just in politics, the workplace, or any other policy-designated sphere. To avoid complication, genders besides women and men will not be discussed in this article. - 1 History - 2 Gender biases - 3 Efforts to fight inequality - 3.1 Violence against women - 3.2 Reproductive and sexual health and rights - 3.3 Freedom of movement - 3.4 Gendered arrangements of work and care - 3.5 Girls' access to education - 3.6 Political participation of women - 3.7 Economic empowerment of women - 3.8 Marriage, divorce and property laws and regulations - 3.9 Investigation and prosecution of crimes against women and girls - 3.10 Gender stereotypes - 3.11 Harmful traditional practices - 3.12 Portrayal of women in the media - 3.13 Health - 3.14 Informing women of their rights - 3.15 Gender mainstreaming - 4 See also - 5 References - 6 External links Christine de Pizan, an early advocate for gender equality, states in her 1405 book The Book of the City of Ladies that the oppression of women is founded on irrational prejudice, pointing out numerous advances in society probably created by women. The Shakers, an evangelical group, which practiced segregation of the sexes and strict celibacy, were early practitioners of gender equality. They branched off from a Quaker community in the north-west of England before emigrating to America in 1774. In America, the head of the Shakers' central ministry in 1788, Joseph Meacham, had a revelation that the sexes should be equal. He then brought Lucy Wright into the ministry as his female counterpart, and together they restructured society to balance the rights of the sexes. Meacham and Wright established leadership teams where each elder, who dealt with the mens' spiritual welfare, was partnered with an eldress, who did the same for women. Each deacon was partnered with a deaconess. Men had oversight of men; women had oversight of women. Women lived with women; men lived with men. In Shaker society, a woman did not have to be controlled or owned by any man. After Meacham's death in 1796, Wright became the head of the Shaker ministry until her death in 1821. Shakers maintained the same pattern of gender-balanced leadership for more than 200 years. They also promoted equality by working together with other women's rights advocates. In 1859, Shaker Elder Frederick Evans stated their beliefs forcefully, writing that Shakers were "the first to disenthrall woman from the condition of vassalage to which all other religious systems (more or less) consign her, and to secure to her those just and equal rights with man that, by her similarity to him in organization and faculties, both God and nature would seem to demand". Evans and his counterpart, Eldress Antoinette Doolittle, joined women's rights advocates on speakers' platforms throughout the northeastern U.S. in the 1870s. A visitor to the Shakers wrote in 1875: - Each sex works in its own appropriate sphere of action, there being a proper subordination, deference and respect of the female to the male in his order, and of the male to the female in her order [emphasis added], so that in any of these communities the zealous advocates of "women’s rights" may here find a practical realization of their ideal. The Shakers were more than a radical religious sect on the fringes of American society; they put equality of the sexes into practice. They demonstrated that equality was achievable and how to achieve it. In wider society, the movement towards gender equality began with the suffrage movement in Western cultures in the late-19th century, which sought to allow women to vote and hold elected office. This period also witnessed significant changes to women's property rights, particularly in relation to their marital status. (See for example, Married Women's Property Act 1882.) After World War II, a more general movement for gender equality developed based on women's liberation and feminism. The central issue was that the rights of women should be the same as of men. Feminists believe that women should be equal in every aspect to men and deserve the same rights that are given to men. The United Nations and other international agencies have adopted several conventions, toward the promotion of gender equality. Prominent international instruments include: - In 1960 the Convention against Discrimination in Education was adopted, coming into force in 1962 and 1968. - The Convention on the Elimination of All Forms of Discrimination against Women (CEDAW) is an international treaty adopted in 1979 by the United Nations General Assembly. Described as an international bill of rights for women, it came into force on 3 September 1981. - The Vienna Declaration and Programme of Action, a human rights declaration adopted by consensus at the World Conference on Human Rights on 25 June 1993 in Vienna, Austria. Women's rights are addressed at para 18. - The Declaration on the Elimination of Violence Against Women was adopted by the United Nations General Assembly in 1993. - In 1994, the twenty-year Cairo Programme of Action was adopted at the International Conference on Population and Development (ICPD) in Cairo. This non binding programme-of-action asserted that governments have a responsibility to meet individuals' reproductive needs, rather than demographic targets. As such, it called for family planning, reproductive rights services, and strategies to promote gender equality and stop violence against women. - Also in 1994, in the Americas, The Inter-American Convention on the Prevention, Punishment, and Eradication of Violence against Women, known as the Convention of Belém do Pará, called for the end of violence and discrimination against women. - At the end of the Fourth World Conference on Women, the UN adopted the Beijing Declaration on 15 September 1995 - a resolution adopted to promulgate a set of principles concerning gender equality. - The United Nations Security Council Resolution 1325 (UNSRC 1325), which was adopted on 31 October 2000, deals with the rights and protection of women and girls during and after armed conflicts. - The Maputo Protocol guarantees comprehensive rights to women, including the right to take part in the political process, to social and political equality with men, to control their reproductive health, and an end to female genital mutilation. It was adopted by the African Union in the form of a protocol to the African Charter on Human and Peoples' Rights and came into force in 2005. - The EU directive Directive 2002/73/EC - equal treatment of 23 September 2002 amending Council Directive 76/207/EEC on the implementation of the principle of equal treatment for men and women as regards access to employment, vocational training and promotion, and working conditions states that: "Harassment and sexual harassment within the meaning of this Directive shall be deemed to be discrimination on the grounds of sex and therefore prohibited." - The Council of Europe's Convention on preventing and combating violence against women and domestic violence, the first legally binding instrument in Europe in the field of violence against women, came into force in 2014. - The Council of Europe's Gender Equality Strategy 2014-2017, which has five strategic objectives: Such legislation and affirmative action policies have been critical to bringing changes in societal attitudes. A 2015 Pew Research Center survey of citizens in 38 countries found that majorities in 37 of those 38 countries said that gender equality is at least "somewhat important," and a global median of 65% believe it is "very important" that women have the same rights as men. Most occupations are now equally available to men and women, in many countries. For example, many countries now permit women to serve in the armed forces, the police forces and to be fire fighters – occupations traditionally reserved for men. Although these continue to have a male majority, an increasing number of women are now active, especially in directive fields such as politics, and occupy high positions in business. Similarly, men are increasingly working in occupations which in previous generations had been considered women's work, such as nursing, cleaning and child care. In domestic situations, the role of Parenting or child rearing is more commonly shared or not as widely considered to be an exclusively female role, so that women may be free to pursue a career after childbirth. For further information, see Shared earning/shared parenting marriage. Another manifestation of the change in social attitudes is the non-automatic taking by a woman of her husband's surname on marriage. A highly contentious issue relating to gender equality is the role of women in religiously orientated societies. For example, the Cairo Declaration on Human Rights in Islam declared that women have equal dignity but not equal rights, and this was accepted by many predominantly Muslim countries. In some Christian churches, the practice of churching of women may still have elements of ritual purification and the Ordination of women to the priesthood may be restricted or forbidden. Some Christians or Muslims believe in Complementarianism, a view that holds that men and women have different but complementing roles. This view may be in opposition to the views and goals of gender equality. In addition, there are also non-Western countries of low religiosity where the contention surrounding gender equality remains. In China, a cultural preference for a male child has resulted in a shortfall of women in the population. The feminist movement in Japan has made many strides which resulted in Rethe Gender Equality Bureau, but Japan still remains low in gender equality compared to other industrialized nations. The notion of gender equality, and of its degree of achievement in a certain country, is very complex because there are countries that have a history of a high level of gender equality in certain areas of life but not in other areas. An example is Finland, which has offered very high opportunities to women in public/professional life but has had a weak legal approach to the issue of violence against women, with the situation in this country having been called a paradox. Denmark received harsh criticism for inadequate laws in regard to sexual violence in a 2008 report produced by Amnesty International, which described Danish laws as "inconsistent with international human rights standards". This led to Denmark reforming its sexual offenses legislation in 2013. Indeed, there is a need for caution when categorizing countries by the level of gender equality that they have achieved. According to Mala Htun and Laurel Weldon "gender policy is not one issue but many" and: - "When Costa Rica has a better maternity leave than the United States, and Latin American countries are quicker to adopt policies addressing violence against women than the Nordic countries, one at least ought to consider the possibility that fresh ways of grouping states would further the study of gender politics." Not all beliefs relating to gender equality have been popularly adopted. For example topfreedom, the right to be bare breasted in public, frequently applies only to males and has remained a marginal issue. Breastfeeding in public is now more commonly tolerated, especially in semi-private places such as restaurants. There has been criticism from some feminists towards the political discourse and policies employed in order to achieve the above items of "progress" in gender equality, with critics arguing that these gender equality strategies are superficial, in that they do not seek to challenge social structures of male domination, and only aim at improving the situation of women within the societal framework of subordination of women to men, and that official public policies (such as sate policies or international bodies policies) are questionable, as they are applied in a patriarchal context, and are directly or indirectly controlled by agents of a system which is for the most part male. One of the criticisms of the gender equality policies, in particular, those of the European Union, is that they disproportionately focus on policies integrating women in public life, but do not seek to genuinely address the deep private sphere oppression. A further criticism is that a focus on the situation of women in non-Western countries, while often ignoring the issues that exist in the West, is a form of imperialism and of reinforcing Western moral superiority; and a way of "othering" of domestic violence, by presenting it as something specific to outsiders - the "violent others" - and not to the allegedly progressive Western cultures. These critics point out that women in Western countries often face similar problems, such as domestic violence and rape, as in other parts of the world. They also cite the fact that women faced de jure legal discrimination until just a few decades ago; for instance, in some Western countries such as Switzerland, Greece, Spain, and France, women obtained equal rights in family law in the 1980s. Another criticism is that there is a selective public discourse with regard to different types of oppression of women, with some forms of violence such as honor killings (most common in certain geographic regions such as parts of Asia and North Africa) being frequently the object of public debate, while other forms of violence, such as the lenient punishment for crimes of passion across Latin America, do not receive the same attention in the West. In 2002, Widney Brown, advocacy director for Human Rights Watch, pointed out that "crimes of passion have a similar dynamic [to honor killings] in that the women are killed by male family members and the crimes are perceived [in those relevant parts of the world] as excusable or understandable". It is also argued that the criticism of particular laws of many developing countries ignores the influence of colonialism on those legal systems, especially of the French Napoleonic Code, which was extremely powerful in its influence over the world (historian Robert Holtman regards it as one of the few documents that have influenced the whole world) and which designated married women a subordinate role, and provided for leniency with regard to 'crimes of passion' (which was the case in France until 1975). Efforts to fight inequality \|This section may need to be rewritten entirely to comply with Wikipedia's quality standards. (June 2013)\| World bodies have defined gender equality in terms of human rights, especially women's rights, and economic development. UNICEF describes that gender equality "means that women and men, and girls and boys, enjoy the same rights, resources, opportunities and protections. It does not require that girls and boys, or women and men, be the same, or that they be treated exactly alike." UNFPA stated that, "despite many international agreements affirming their human rights, women are still much more likely than men to be poor and illiterate. They have less access to property ownership, credit, training and employment. They are far less likely than men to be politically active and far more likely to be victims of domestic violence." Thus, promoting gender equality is seen as an encouragement to greater economic prosperity. For example, nations of the Arab world that deny equality of opportunity to women were warned in a 2008 United Nations-sponsored report that this disempowerment is a critical factor crippling these nations' return to the first rank of global leaders in commerce, learning, and culture. That is, Western bodies are less likely to conduct commerce with nations in the Middle East that retain culturally accepted attitudes towards the status and function of women in their society in an effort to force them to change their beliefs in the face of relatively underdeveloped economies. Gender equality is part of the national curriculum in Great Britain and many other European countries. Personal, Social and Health Education, religious studies and Language acquisition curricula tend to address gender equality issues as a very serious topic for discussion and analysis of its effect in society. A large and growing body of research has shown how gender inequality undermines health and development. To overcome gender inequality the United Nations Population Fund states that, "Women's empowerment and gender equality requires strategic interventions at all levels of programming and policy-making. These levels include reproductive health, economic empowerment, educational empowerment and political empowerment." Violence against women Violence against women is a technical term used to collectively refer to violent acts that are primarily or exclusively committed against women. This type of violence is gender-based, meaning that the acts of violence are committed against women expressly because they are women, or as a result of patriarchal gender constructs. The UN Declaration on the Elimination of Violence Against Women defines violence against women as "any act of gender-based violence that results in, or is likely to result in, physical, sexual or psychological harm or suffering to women, including threats of such acts, coercion or arbitrary deprivation of liberty, whether occurring in public or in private life" and states that: - "violence against women is a manifestation of historically unequal power relations between men and women, which have led to domination over and discrimination against women by men and to the prevention of the full advancement of women, and that violence against women is one of the crucial social mechanisms by which women are forced into a subordinate position compared with men" According to some theories, violence against women is often caused by the acceptance of violence by various cultural groups as a means of conflict resolution within intimate relationships. Studies on IPV victimization among ethnic minorities in the United Studies have consistently revealed that immigrants are a high-risk group for intimate violence. Forms of violence against women include sexual violence (including war rape, marital rape, date rape by drugs or alcohol, and child sexual abuse, the latter often in the context of child marriage), domestic violence, forced marriage, female genital mutilation, forced prostitution, sex trafficking, honor killings, dowry killings, acid attacks, stoning, flogging, forced sterilization, forced abortion, violence related to accusations of witchcraft, mistreatment of widows (e.g. widow inheritance). Fighting against violence against women is considered a key issues for achieving gender equality. The Council of Europe adopted the Convention on preventing and combating violence against women and domestic violence (Istanbul Convention). In Western countries, which are believed to be overall safe (i.e. where gang murders, armed kidnappings, civil unrest, and other similar acts are rare), the vast majority of murdered women are killed by partners/ex-partners: as of 2004-2009, former and current partners were responsible for more than 80% of all cases of murders of women in Cyprus, France, and Portugal. By contrast, in countries with a high level of organized criminal activity and gang violence murders of women are more likely to occur in a public sphere, often in a general climate of indifference and impunity. In addition, many countries do not have adequate comprehensive data collection on such murders, aggravating the problem. In some parts of the world, various forms of violence against women are tolerated and accepted as parts of everyday life; according to UNFPA: - "In some developing countries, practices that subjugate and harm women - such as wife-beating, killings in the name of honour, female genital mutilation/cutting and dowry deaths - are condoned as being part of the natural order of things." In most countries, it is only in more recent decades that violence against women (in particular when committed in the family) has received significant legal attention. The Istanbul Convention acknowledges the long tradition of European countries of ignoring, de jure or de facto, this form of violence. In its explanatory report at para 219, it states: - "There are many examples from past practice in Council of Europe member states that show that exceptions to the prosecution of such cases were made, either in law or in practice, if victim and perpetrator were, for example, married to each other or had been in a relationship. The most prominent example is rape within marriage, which for a long time had not been recognised as rape because of the relationship between victim and perpetrator." In Opuz v Turkey, the European Court of Human Rights recognized violence against women as a form discrimination against women, para 200: "[T]he Court considers that the violence suffered by the applicant and her mother may be regarded as gender-based violence which is a form of discrimination against women." This is also the position of the Istanbul Convention which reads: - "Article 3 – Definitions, For the purpose of this Convention: a "violence against women" is understood as a violation of human rights and a form of discrimination against women [...]". In some cultures, acts of violence against women are seen as crimes against the male 'owners' of the woman, such as husband, father or male relatives, rather the woman herself. This leads to practices where men inflict violence upon women in order to get revenge on male members of the women's family. Such practices include payback rape, a form of rape specific to certain cultures, particularly the Pacific Islands, which consists of the rape of a female, usually by a group of several males, as revenge for acts committed by members of her family, such as her father or brothers, with the rape being meant to humiliate the father or brothers, as punishment for their prior behavior towards the perpetrators. Reproductive and sexual health and rights The importance of women having the right and possibility to have control over their body, reproduction decisions, and sexuality, and the need for gender equality in order to achieve these goals are recognized as crucial by the Fourth World Conference on Women in Beijing and the UN International Conference on Population and Development Program of Action. The World Health Organization (WHO) has stated that promotion of gender equality is crucial in the fight against HIV/AIDS. Maternal mortality is a major problem in many parts of the world. UNFPA states that countries have an obligation to protect women's right to health, but many countries do not do that. Maternal mortality is considered today not just an issue of development but also an issue of human rights. UNFPA says that, "since 1990, the world has seen a 45 per cent decline in maternal mortality – an enormous achievement. But in spite of these gains, almost 800 women still die every day from causes related to pregnancy or childbirth. This is about one woman every two minutes." According to UNFPA: - "Preventable maternal mortality occurs where there is a failure to give effect to the rights of women to health, equality, and non-discrimination. Preventable maternal mortality also often represents a violation of a woman’s right to life." The right to reproductive and sexual autonomy is denied to women in many parts of the world, through practices such as forced sterilization, forced/coerced sexual partnering (e.g. forced marriage, child marriage), criminalization of consensual sexual acts (such as sex outside marriage), lack of criminalization of marital rape, violence in regard to the choice of partner (honor killings as punishment for 'inappropriate' relations). Amnesty International’s Secretary General has stated that: "It is unbelievable that in the twenty-first century some countries are condoning child marriage and marital rape while others are outlawing abortion, sex outside marriage and same-sex sexual activity – even punishable by death." These practices infringe on the right of achieving reproductive and sexual health. High Commissioner for Human Rights Navi Pillay has called for full respect and recognition of women's autonomy and sexual and reproductive health rights, stating: - "Violations of women's human rights are often linked to their sexuality and reproductive role. Women are frequently treated as property, they are sold into marriage, into trafficking, into sexual slavery. Violence against women frequently takes the form of sexual violence. Victims of such violence are often accused of promiscuity and held responsible for their fate, while infertile women are rejected by husbands, families, and communities. In many countries, married women may not refuse to have sexual relations with their husbands, and often have no say in whether they use contraception." Adolescent girls have the highest risk of sexual coercion, sexual ill health, and negative reproductive outcomes. The risks they face are higher than those of boys and men; this increased risk is partly due to gender inequity (different socialization of boys and girls, gender based violence, child marriage) and partly due to biological factors (females' risk of acquiring sexually transmitted infections during unprotected sexual relations is two to four times that of males'). Socialization within rigid gender constructs often creates an environment where sexual violence is common; according to the WHO: "Sexual violence is also more likely to occur where beliefs in male sexual entitlement are strong, where gender roles are more rigid, and in countries experiencing high rates of other types of violence." The sexual health of women is often poor in societies where a woman's right to control her sexuality is not recognized. Richard A. Posner writes that "Traditionally, rape was the offense of depriving a father or husband of a valuable asset — his wife's chastity or his daughter's virginity". Historically, rape was seen in many cultures (and is still seen today in some societies) as a crime against the honor of the family, rather than against the self-determination of the woman. As a result, victims of rape may face violence, in extreme cases even honor killings, at the hands of their family members. Catharine MacKinnon argues that in male dominated societies, sexual intercourse is imposed on women in a coercive and unequal way, creating a continuum of victimization, where women have few positive sexual experiences; she writes "To know what is wrong with rape, know what is right about sex. If this, in turn, is difficult, the difficulty is as instructive as the difficulty men have in telling the difference when women see one. Perhaps the wrong of rape has proved so difficult to define because the unquestionable starting point has been that rape is defined as distinct from intercourse, while for women it is difficult to distinguish the two under conditions of male dominance." One of the challenges of dealing with sexual violence is that in many societies women are perceived as being readily available for sex, and men are seen as entitled to their bodies, until and unless women object. Rebecca Cook wrote in Submission of Interights to the European Court of Human Rights in the case of M.C. v. Bulgaria, 12 April 2003: - "The equality approach starts by examining not whether the woman said 'no', but whether she said 'yes'. Women do not walk around in a state of constant consent to sexual activity unless and until they say 'no', or offer resistance to anyone who targets them for sexual activity. The right to physical and sexual autonomy means that they have to affirmatively consent to sexual activity." Freedom of movement The degree to which women can participate (in law and in practice) in public life varies by culture, historical era, social class and other other socioeconomic characteristics. Seclusion of women within the home was a common practice among the upper classes of many societies, and this still remains the case today in some societies. Before the 20th century it was also common in parts of Southern Europe, such as much of Spain. Women's freedom of movement continues to be legally restricted in some parts of the world. This restriction is often due to marriage laws. For instance, in Yemen, marriage regulations stipulate that a wife must obey her husband and must not leave home without his permission. In some countries, women must legally be accompanied by their male guardians (such as the husband or male relative) when they leave home. The CEDAW states at Article 15 (4) that: - Article 15 - "4. States Parties shall accord to men and women the same rights with regard to the law relating to the movement of persons and the freedom to choose their residence and domicile." In addition to laws, women's freedom of movement is also restricted by social and religious norms - for example, purdah, a religious and social practice of female seclusion prevalent among some Muslim communities in Afghanistan and Pakistan as well as upper-caste Hindus in Northern India, such as the Rajputs, which often leads to the minimizing of the movement of women in public spaces and restrictions on their social and professional interactions; or namus, a cultural concept strongly related to family honor. The custom of bride price can also curtail the free movement of women: if a wife wants to leave her husband, he may demand back the bride price that he had paid to the woman's family; and the woman's family often cannot or does not want to pay it back, making it difficult for women to move out of violent husbands' homes. Restrictions on freedom of movement also exist due to traditional practices such as baad, swara, or vani, common especially among Pashtun tribes in Pakistan and Afghanistan, whereby a girl is given from one family to another (often though a marriage), in order to settle the disputes and feuds between the families. The girl, who now belongs to the second family, has very little autonomy and freedom, her role being to serve the new family. Gendered arrangements of work and care Since the 1950s, social scientists as well as feminists have increasingly criticized gendered arrangements of work and care and the male breadwinner role. Policies are increasingly targeting men as fathers as a tool of changing gender relations. Shared earning/shared parenting marriage, that is, a relationship where the partners collaborate at sharing their responsibilities inside and outside of the home, is often encouraged in Western countries. Western countries with a strong emphasis on women fulfilling the role of homemakers, rather than a professional role, include parts of German speaking Europe - parts of Germany, Austria and Switzerland; as well as the Netherlands and Ireland. In 2011, Jose Manuel Barroso, then president of the European Commission, stated "Germany, but also Austria and the Netherlands, should look at the example of the northern countries [...] that means removing obstacles for women, older workers, foreigners and low-skilled job-seekers to get into the workforce". The Netherlands and Ireland are among the last Western countries to accept women as professionals; despite the Netherlands having an image as progressive on gender issues, women in the Netherlands work less in paid employment than women in other comparable Western countries. In the early 1980s, the Commission of the European Communities report Women in the European Community, found that the Netherlands and Ireland had the lowest labour participation of married women and the most public disapproval of it. In Ireland, until 1973, there was a marriage bar. In the Netherlands, from the 1990s onwards, the numbers of women entering the workplace have increased, but with most of the women working part time. As of 2014, the Netherlands and Switzerland were the only OECD members where most employed women worked part-time, while in the United Kingdom, women made up two-thirds of workers on long term sick leave, despite making up only half of the workforce and even after excluding maternity leave. A key issue towards insuring gender equality in the workplace is the respecting of maternity rights and reproductive rights of women. Different countries have different rules regarding maternity leave, paternity leave and parental leave. In the European Union (EU) the policies vary significantly by country, but the EU members must abide by the minimum standards of the Pregnant Workers Directive and Parental Leave Directive. Another important issue refers to ensuring that employed women are not de jure or de facto prevented from having a child. For example, some countries have enacted legislation explicitly outlawing or restricting what they view as abusive clauses in employment contracts regarding reproductive rights (for example clauses which stipulate that a woman cannot get pregnant during a specified time) rendering such contracts void or voidable. In some countries, employers who request women to sign formal or informal documents stipulating that they will not get pregnant face legal punishment. Women often face severe violations of their reproductive rights at the hands of their employers; and the International Labour Organization classifies forced abortion coerced by the employer as labour exploitation. Being the victim of a forced abortion compelled by the employer was ruled a ground of obtaining political asylum in the US. Other abuses include routine virginity tests of unmarried employed women. Girls' access to education In many parts of the world, girls' access to education is very restricted. In developing parts of the world women are often denied opportunities for education as girls and women face many obstacles. These include: early and forced marriages; early pregnancy; prejudice based on gender stereotypes at home, at school and in the community; violence on the way to school, or in and around schools; long distances to schools; vulnerability to the HIV epidemic; school fees, which often lead to parents sending only their sons to school; lack of gender sensitive approaches and materials in classrooms. According to OHCHR, there have been multiple attacks on schools worldwide during the period 2009-2014 with "a number of these attacks being specifically directed at girls, parents and teachers advocating for gender equality in education". The United Nations Population Fund says: - "About two thirds of the world's illiterate adults are women. Lack of an education severely restricts a woman's access to information and opportunities. Conversely, increasing women's and girls' educational attainment benefits both individuals and future generations. Higher levels of women's education are strongly associated with lower infant mortality and lower fertility, as well as better outcomes for their children." Political participation of women Women are underrepresented in most countries' National Parliaments. The 2011 UN General Assembly resolution on women’s political participation called for female participation in politics, and expressed concern about the fact that "women in every part of the world continue to be largely marginalized from the political sphere". The Council of Europe states that: - "Pluralist democracy requires balanced participation of women and men in political and public decision-making. Council of Europe standards provide clear guidance on how to achieve this." Institutions also play an essential role in achieving and enforcing gender equality. However, basic legal and human rights, access to and the control of resources, employment and earnings and social and political participation are still not guaranteed in many social and legal institutions. For example, only 22 percent of parliamentarians globally are women and therefore, men continue to occupy most positions of political and legal authority. As of November 2014, women accounted for 28% of members of the single or lower houses of parliaments in the European Union member states. In some Western countries women have only recently obtained the right to vote, notably in Switzerland, where women gained the right to vote in federal elections in 1971; but in the canton of Appenzell Innerrhoden women obtained the right to vote on local issues only in 1991, when the canton was forced to do so by the Federal Supreme Court of Switzerland. In Liechtenstein, women were given the right to vote by the women's suffrage referendum of 1984. Three prior referendums held in 1968, 1971 and 1973 had failed to secure women's right to vote. Economic empowerment of women Female economic activity is a common measure of gender equality in an economy. UN Women states that: "Investing in women’s economic empowerment sets a direct path towards gender equality, poverty eradication and inclusive economic growth." Gender discrimination often results in women obtaining low-wage jobs and being disproportionately affected by poverty, discrimination and exploitation. The UN Population Fund says that, "Six out of 10 of the world’s poorest people are women. Economic disparities persist partly because much of the unpaid work within families and communities falls on the shoulders of women, and because women continue to face discrimination in the economic sphere." Gender biases also exist in product and service provision. The term "Women's Tax", also known as "Pink Tax", refers to gendered pricing in which products or services marketed to women are more expensive than similar products marketed to men. Gender-based price discrimination involves companies selling almost identical units of the same product or service at comparatively different prices, as determined by the target market. Studies have found that women pay about $1,400 a year more than men due to gendered discriminatory pricing. Although the "pink tax" of different goods and services is not uniform, overall women pay more for commodities that result in visual evidence of feminine body image. For example, studies have shown that women are charged more for services especially tailoring, hair cutting and laundering. A growing body of research documents what works to economically empower women, from providing access to formal financial services to training on agricultural and business management practices, though more research is needed across a variety of contexts to confirm the effectiveness of these interventions. Marriage, divorce and property laws and regulations Equal rights for women in marriage, divorce, and property/land ownership and inheritance are essential for gender equality. CEDAW has called for the end of discriminatory family laws. In 2013, UN Women stated that "While at least 115 countries recognize equal land rights for women and men, effective implementation remains a major challenge". The legal and social treatment of married women has been often discussed as a political issue from the 19th century onwards. John Stuart Mill, in The Subjection of Women (1869) compared marriage to slavery and wrote that: "The law of servitude in marriage is a monstrous contradiction to all the principles of the modern world, and to all the experience through which those principles have been slowly and painfully worked out." In 1957, James Everett, then Minister for Justice in Ireland, stated: "The progress of organised society is judged by the status occupied by married women". Until the 1970s, legal subordination of married women was common across European countries, through marriage laws giving legal authority to the husband, as well as through marriage bars. In France, married women obtained the right to work without their husband's consent in 1965; while the paternal authority of a man over his family was ended in 1970 (before that parental responsibilities belonged solely to the father who made all legal decisions concerning the children); and a new reform in 1985 abolished the stipulation that the father had the sole power to administer the children's property. In Austria, the marriage law was overhauled between 1975 and 1983, abolishing the restrictions on married women's right to work outside the home, providing for equality between spouses, and for joint ownership of property and assets. Switzerland was one of the last countries in Europe to establish gender equality in marriage, in this country married women's rights were severely restricted until 1988, when legal reforms providing for gender equality in marriage, abolishing the legal authority of the husband, come into force (these reforms had been approved in 1985 by voters in a referendum, who narrowly voted in favor with 54.7% of voters approving). In the Netherlands, although the legal incapacity of a married woman was abolished in 1956, the marriage bar for women civil servants being lifted in 1957, it was only in 1984 that full legal equality between husband and wife was achieved - prior to 1984 the law stipulated that the husband's opinion prevailed over the wife's regarding issues such as decisions on children's education and the domicile of the family. In 1978, the Council of Europe passed the Resolution (78) 37 on equality of spouses in civil law. In the United States, a wife's legal subordination to her husband was fully ended by the case of Kirchberg v. Feenstra, 450 U.S. 455 (1981), a United States Supreme Court case in which the Court held a Louisiana Head and Master law, which gave sole control of marital property to the husband, unconstitutional. There have been and sometimes continue to be unequal treatment of married women in various aspects of everyday life. For example, in Australia, until 1983 a husband had to authorize a passport application for a married woman. Other practices have included, and in many countries continue to include, a requirement for a husband's consent for an application for bank loans and credit cards by a married woman, as well as restrictions on the wife's reproductive rights, such as a requirement that the husband consents to the wife's acquiring of contraception or having an abortion. In some places, although the law itself no longer requires the consent of the husband for various actions taken by the wife, the practice continues de facto, with the authorization of the husband being asked in practice. Although dowry is today associated with South Asia, the practice has been common until the mid-20th century in parts of Southeast Europe. For example, in Greece dowry was removed from family law only in 1983 through legal changes which reformed marriage law and provided gender equality in marriage. These changes also dealt with the practice of women changing their surnames to that of the husbands upon getting married, a practice which has been outlawed or restricted in some jurisdictions, because it is seen as contrary to women's rights. As such, women in Greece are required to keep their birth names for their whole life. Laws regulating marriage and divorce continue to discriminate against women in many countries. For example, in Yemen, marriage regulations state that a wife must obey her husband and must not leave home without his permission. In Iraq husbands have a legal right to "punish" their wives, with paragraph 41 of the criminal code stating that there is no crime if an act is committed while exercising a legal right. Examples of legal rights include: "The punishment of a wife by her husband, the disciplining by parents and teachers of children under their authority within certain limits prescribed by law or by custom". In the 1990s and the 21st century there has been progress in many countries in Africa: for instance in Namibia the marital power of the husband was abolished in 1996 by the Married Persons Equality Act; in Botswana it was abolished in 2004 by the Abolition of Marital Power Act; and in Lesotho it was abolished in 2006 by the Married Persons Equality Act. Violence and mistreatment of women in relation to marriage has come to international attention during the past decades. This includes both violence committed inside marriage (domestic violence) as well as violence related to marriage customs and traditions (such as dowry, bride price, forced marriage and child marriage). Violence against a wife continues to be seen as legally acceptable in some countries; for instance in 2010, the United Arab Emirates's Supreme Court ruled that a man has the right to physically discipline his wife and children as long as he does not leave physical marks. The criminalization of adultery has been criticized as being a prohibition, which, in law or in practice, is used primarily against women; and incites violence against women (crimes of passion, honor killings). A Joint Statement by the United Nations Working Group on discrimination against women in law and in practice in 2012 stated: "the United Nations Working Group on discrimination against women in law and in practice is deeply concerned at the criminalization and penalization of adultery whose enforcement leads to discrimination and violence against women." UN Women also stated that "Drafters should repeal any criminal offenses related to adultery or extramarital sex between consenting adults". Investigation and prosecution of crimes against women and girls Human rights organizations have expressed concern about the legal impunity of perpetrators of crimes against women, with such crimes being often ignored by authorities. This is especially the case with murders of women in Latin America. In particular, there is impunity in regard to domestic violence. High Commissioner for Human Rights, Navi Pillay, has stated on domestic violence against women: - "The reality for most victims, including victims of honor killings, is that state institutions fail them and that most perpetrators of domestic violence can rely on a culture of impunity for the acts they commit – acts which would often be considered as crimes, and be punished as such, if they were committed against strangers." Women are often, in law or in practice, unable to access legal institutions. UN Women has said that: "Too often, justice institutions, including the police and the courts, deny women justice". Often, women are denied legal recourse because the state institutions themselves are structured and operate in ways incompatible with genuine justice for women who experience violence - according to Amnesty International, "Women who are victims of gender-related violence often have little recourse because many state agencies are themselves guilty of gender bias and discriminatory practices." Gender stereotypes arise from the socially approved roles of women and men in the private or public sphere, at home or in the workplace.In the household, women are typically seen as mother figures, which usually places them into a typical classification of being "supportive" or "nurturing". Women are expected to want to take on the role of a mother and take on primary responsibility for household needs. Their male counterparts are seen as being "assertive" or "ambitious" as men are usually seen in the workplace or as the primary breadwinner for his family. Due to these views and expectations, women often face discrimination in the public sphere, such as the workplace. A gender role is a set of societal norms dictating the types of behaviors which are generally considered acceptable, appropriate, or desirable for people based on their sex. Gender roles are usually centered on conceptions of femininity and masculinity, although there are exceptions and variations. The Istanbul Convention contains a definition of "gender", stating that: "“gender” shall mean the socially constructed roles, behaviours, activities and attributes that a given society considers appropriate for women and men". (Article 3–Definitions (c)) Harmful traditional practices "Harmful traditional practices" refer to forms of violence which are committed in certain communities often enough to become cultural practice, and accepted for that reason. Young women are the main victims of such acts, although men can be affected. They occur in an environment where women and girls have unequal rights and opportunities. These practices include, according to the Office of the United Nations High Commissioner for Human Rights: - "female genital mutilation (FGM); forced feeding of women; early marriage; the various taboos or practices which prevent women from controlling their own fertility; nutritional taboos and traditional birth practices; son preference and its implications for the status of the girl child; female infanticide; early pregnancy; and dowry price" Female genital mutilation is defined as "procedures that intentionally alter or cause injury to the female genital organs for non-medical reasons". An estimated 125 million women and girls living today have undergone FGM in the 29 countries where data exist. Of these, about half live in two countries, Egypt and Ethiopia. It is most commonly carried out on girls between infancy and 15 years old. UNFPA and UNICEF state that, "In every society where it is practiced, FGM is a manifestation of deeply entrenched gender inequality. It persists for many reasons. In some societies, for example, it is considered a rite of passage. In others, it is seen as a prerequisite for marriage. In some communities, whether Christian, Jewish, Muslim, the practice may even be attributed to religious beliefs. Because FGM may be considered an important part of a culture or identity, it can be difficult for families to decide against having their daughters cut. People who reject the practice may face condemnation or ostracism. Even parents who do not want their daughters to undergo FGM may feel compelled to participate in the practice." Son preference refers to a cultural preference for sons over daughters, and manifests itself through practices such as sex selective abortion; female infanticide; or abandonment, neglect or abuse of girl-children. Early marriage, child marriage or forced marriage is prevalent in parts of Asia and Africa. The majority of victims seeking advice are female and aged between 18 and 23. Such marriages can have harmful effects on a girl's education and development, and may expose girls to social isolation or abuse. The 2013 UN Resolution on Child, Early and Forced Marriage calls for an end to the practice, and states that "Recognizing that child, early and forced marriage is a harmful practice that violates abuses, or impairs human rights and is linked to and perpetuates other harmful practices and human rights violations, that these violations have a disproportionately negative impact on women and girls [...]". Despite a near-universal commitment by governments to end child marriage, "one in three girls in developing countries (excluding China) will probably be married before they are 18." UNFPA states that, "over 67 million women 20-24 year old in 2010 had been married as girls. Half were in Asia, one-fifth in Africa. In the next decade 14.2 million girls under 18 will be married every year; this translates into 39,000 girls married each day. This will rise to an average of 15.1 million girls a year, starting in 2021 until 2030, if present trends continue." Abuses regarding nutrition are taboos in regard to certain foods, which result in poor nutrition of women, and may endanger their health, especially if pregnant. Women's ability to control their fertility is often reduced. For instance, in northern Ghana, the payment of bride price signifies a woman's requirement to bear children, and women using birth control face threats, violence and reprisals. Births in parts of Africa are often attended by traditional birth attendants (TBAs), who sometimes perform rituals that are dangerous to the health of the mother. In many societies, a difficult labour is believed to be a divine punishment for marital infidelity, and such women face abuse and are pressured to "confess" to the infidelity. The custom of bride price has been criticized as contributing to the mistreatment of women in marriage, and preventing them from leaving abusive marriages. UN Women recommended its abolition, and stated that: "Legislation should [...] State that divorce shall not be contingent upon the return of bride price but such provisions shall not be interpreted to limit women’s right to divorce; State that a perpetrator of domestic violence, including marital rape, cannot use the fact that he paid bride price as a defence to a domestic violence charge." The caste system in India which leads to untouchability (the practice of ostracizing a group by segregating them from the mainstream society) often interacts with gender discrimination, leading to a double discrimination faced by Dalit women. In a 2014 survey, 27% of Indians admitted to practicing untouchability. Tribal traditions can be harmful to males; for instance, the Satere-Mawe tribe use bullet ants as an initiation rite. Men must wear gloves with hundreds of bullet ants woven in for ten minutes: the ants' stings cause severe pain and paralysis. This experience must be completed twenty times for boys to be considered "warriors". Portrayal of women in the media The way women are represented in the media has been criticized as interfering with the aim of achieving gender equality by perpetuating negative gender stereotypes. The exploitation of women in mass media refers to the criticisms that are levied against the use or objectification of women in the mass media, when such use or portrayal aims at increasing the appeal of media or a product, to the detriment of, or without regard to, the interests of the women portrayed, or women in general. Concerns include the fact that all forms of media have the power to shape the population's perceptions and portray images of unrealistic stereotypical perceptions that falsely implies that women are unimportant or invisible. Criticisms of the way women are represented in the media is that the media reinforces stereotypical societal views of "what women are for", by portraying women either as submissive housewives or as sex objects. The media emphasizes traditional domestic or sexual roles that normalize violence against women. According to a study, the way women are often portrayed by the media can lead to: "Women of average or normal appearance feeling inadequate or less beautiful in comparison to the overwhelming use of extraordinarily attractive women"; "Increase in the likelihood and acceptance of sexual violence"; "Unrealistic expectations by men of how women should look or behave"; "Psychological disorders such as body dysmorphic disorder, anorexia, bulimia and so on"; "The importance of physical appearance is emphasized and reinforced early in most girls' development." Studies have found that nearly half of females ages 6–8 have stated they want to be slimmer. (Striegel-Moore & Franko, 2002)". Social constructs of gender (that is, cultural ideals of socially acceptable masculinity and femininity) often have a negative effect on health. The WHO cites the example of women not being allowed to travel alone outside the home (to go to the hospital), and women being prevented by cultural norms to ask their husbands to use a condom, in cultures which simultaneously encourage male promiscuity, as social norms that harm women's health. Teenage boys suffering accidents due to social expectations of impressing their peers through risk taking, and men dying at much higher rate from lung cancer due to smoking, in cultures which link smoking to masculinity, are cited by the WHO as examples of gender norms negatively affecting men's health. The WHO has also stated that there is a strong connection between gender socialization and transmission and lack of adequate management of HIV/AIDS. Informing women of their rights While in many countries, the problem lies in the lack of adequate legislation, in others the principal problem is not as much the lack of a legal framework, but the fact is that most women do not know their legal rights. This is especially the case as many of the laws dealing with women's rights are of recent date. This lack of knowledge enables to abusers to lead the victims (explicitly or implicitly) to believe that their abuse is within their rights. This may apply to a wide range of abuses, ranging from domestic violence to employment discrimination. The United Nations Development Programme states that, in order to advance gender justice, "Women must know their rights and be able to access legal systems". The 1993 UN Declaration on the Elimination of Violence Against Women states at Art. 4 (d) [...] "States should also inform women of their rights in seeking redress through such mechanisms". Enacting protective legislation against violence has little effect, if women do not know how to use it: for example a study of Bedouin women in Israel found that 60% did not know what a restraining order was; or if they don't know what acts are illegal: a report by Amnesty International showed in Hungary, in a public opinion poll of nearly 1,200 people in 2006, a total of 62% did not know that marital rape was an illegal (it was outlawed in 1997) and therefore the crime was rarely reported. Ensuring women have a minim understanding of health issues is also important: lack of access to reliable medical information and available medical procedures to which they are entitled hurts women's health. Gender mainstreaming is described as the public policy of assessing the different implications for women and men of any planned policy action, including legislation and programmes, in all areas and levels, with the aim of achieving gender equality. The concept of gender mainstreaming was first proposed at the 1985 Third World Conference on Women in Nairobi, Kenya. The idea has been developed in the United Nations development community. Gender mainstreaming "involves ensuring that gender perspectives and attention to the goal of gender equality are central to all activities". According to the Council of Europe definition: "Gender mainstreaming is the (re)organization, improvement, development and evaluation of policy processes, so that a gender equality perspective is incorporated in all policies at all levels and at all stages, by the actors normally involved in policy-making." An integrated gender mainstreaming approach is "the attempt to form alliances and common platforms that bring together the power of faith and gender-equality aspirations to advance human rights." For example, "in Azerbaijan, UNFPA conducted a study on gender equality by comparing the text of the Convention on the Elimination of All Forms of Discrimination against Women with some widely recognized Islamic references and resources. The results reflect the parallels between the Convention and many tenets of Islamic scripture and practice. The study showcased specific issues, including VAW, child marriage, respect for the dignity of women, and equality in the economic and political participation of women. The study was later used to produce training materials geared towards sensitizing religious leaders." \|This section may need to be rewritten entirely to comply with Wikipedia's quality standards. (June 2013)\| - Coloniality of gender - Special Measures for Gender Equality in The United Nations(UN) - Equal opportunity - Gender inequality - Gender mainstreaming - Gender neutrality - Gender role - Men's rights - Right to equal protection - Sex and gender distinction - Sex ratio - Women's rights - Bahá'í Faith and gender equality - Female economic activity - Female education - Gender-based price discrimination - Gender Parity Index (in education) - Gender polarization - Gender sensitization - Mixed-sex education - Quaker Testimony of Equality - Shared Earning/Shared Parenting Marriage (also known as Peer Marriage) - Women in Islam - Anti-discrimination law - Danish Act of Succession referendum, 2009 - Equal Pay Act of 1963 (United States) - Equality Act 2006 (UK) - Equality Act 2010 (UK) - European charter for equality of women and men in local life - Gender Equality Duty in Scotland - Gender Equity Education Act (Taiwan) - Lilly Ledbetter Fair Pay Act (United States, 2009) - List of gender equality lawsuits - Paycheck Fairness Act (in the US) - Title IX of the Education Amendments of 1972 (United States) - Uniform civil code (India) - United Nations Security Council Resolution 1325 - Women's Petition to the National Assembly (France, 1789) Organizations and ministries - Afghan Ministry of Women Affairs (Afghanistan) - Center for Development and Population Activities (CEDPA) - Christians for Biblical Equality - Committee on Women's Rights and Gender Equality (European Parliament) - Equal Opportunities Commission (UK) - Gender Empowerment Measure, a metric used by the United Nations - Gender-related Development Index, a metric used by the United Nations - Government Equalities Office (UK) - International Center for Research on Women - International Society for Peace - Ministry of Integration and Gender Equality (Sweden) - Ministry of Women, Family and Community Development (Malaysia) - Philippine Commission on Women (Philippines) - The Girl Effect, an organization to help girls, worldwide, toward ending poverty Historical anecdotal reports - Global Gender Gap Report - International Men's Day - Potty parity - Women's Equality Day - Illustrators for Gender Equality - Gender apartheid - United Nations. Report of the Economic and Social Council for 1997. A/52/3.18 September 1997, at 28: "Mainstreaming a gender perspective is the process of assessing the implications for women and men of any planned action, including legislation, policies or programmes, in all areas and at all levels. It is a strategy for making women's as well as men's concerns and experiences an integral dimension of the design, implementation, monitoring and evaluation of policies and programmes in all political, economic and societal spheres so that women and men benefit equally and inequality is not perpetuated. The ultimate goal is to achieve gender equality." - "Universal Declaration of Human Rights" (PDF). wwda.org. United Nations. December 16, 1948. Retrieved October 31, 2016. - Riane Eisler (2007). The Real Wealth of Nations: Creating a Caring Economics. p. 72. - Evans, Frederick William (1859). Shakers: Compendium of the Origin, History, Principles, Rules and Regulations, Government, and Doctrines of the United Society of Believers in Christ's Second Appearing. New York: D. Appleton & Co. p. 34. - Glendyne R. Wergland, Sisters in the Faith: Shaker Women and Equality of the Sexes (Amherst: University of Massachusetts Press, 2011). - Wendy R. Benningfield, Appeal of the Sisterhood: The Shakers and the Woman’s Rights Movement (University of Kentucky Lexington doctoral dissertation, 2004), p. 73. - United Nations High Commissioner for Refugees. "Vienna Declaration and Programme of Action". United Nations High Commissioner for Refugees. Retrieved 14 June 2015. - Organization of American States. "Follow-up Mechanism to the Belém do Pará Convention (MESECVI): About the Belém do Pará Convention". Organization of American States. Retrieved 14 June 2015. - EUR-Lex (9 February 1976). Council directive (pdf). EUR-Lex Access to European Union law. - The Convention of Belém do Pará and the Istanbul Convention: a response to violence against women worldwide (pdf). Organization of American States, Council of Europe, Permanent Mission of France to the United Nations and Permanent Mission of Argentina to the United Nations. March 2014. CSW58 side event flyer 2014. - Council of Europe, Committee of Ministers, CM document (CM). "Committee of Ministers - Gender Equality Commission (GEC) - Gender Equality Strategy 2014-2017 [1183 meeting]". Retrieved 14 June 2015. - "Strong global support for gender equality, especially among women". 2016-03-08. Retrieved 2016-08-12. - "Why should women change their names on getting married?". BBC News. BBC. Retrieved 14 June 2015. - Clarke, Kris (August 2011). "The paradoxical approach to intimate partner violence in Finland". International Perspectives in Victimology. Tokiwa University via The Press at California State University. 6 (1): 9–19. doi:10.5364/ipiv.6.1.19. Available through academia.edu. - McKie, Linda; Hearn, Jeff (August 2004). "Gender-neutrality and gender equality: comparing and contrasting policy responses to 'domestic violence' in Finland and Scotland". Scottish Affairs. Edinburgh University Press. 48 (1): 85–107. doi:10.3366/scot.2004.0043. Pdf. - Danish, Swedish, Finnish and Norwegian sections of Amnesty International (March 2010), "Rape and human rights in Finland", in Danish, Swedish, Finnish and Norwegian sections of Amnesty International, Case closed: rape and human rights in the Nordic countries, Amnesty International, pp. 89–91, Finland is repeatedly reminded of its widespread problem of violence against women and recommended to take more efficient measures to deal with the situation. International criticism concentrates on the lack of measures to combat violence against women in general and in particular on the lack of a national action plan to combat such violence and on the lack of legislation on domestic violence. (...) Compared to Sweden, Finland has been slower to reform legislation on violence against women. In Sweden, domestic violence was already illegal in 1864, while in Finland such violence was not outlawed until 1970, over a hundred years later. In Sweden the punishment of victims of incest was abolished in 1937 but not until 1971 in Finland. Rape within marriage was criminalised in Sweden in 1962, but the equivalent Finnish legislation only came into force in 1994 — making Finland one of the last European countries to criminalise marital rape. In addition, assaults taking place on private property did not become impeachable offences in Finland until 1995. 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Retrieved 14 June 2015. \|Wikimedia Commons has media related to Gender equality.\| \|Library resources about - United Nations Rule of Law: Gender Equality, on the relationship between gender equality, the rule of law and the United Nations. - Women and Gender Equality, the United Nations Internet Gateway on Gender Equality and Empowerment of Women. - Gender Equality, an overview of the United Nations Development Program's work on Gender Equality. - Gender Equality as Smart Economics The World Bank. - GENDERNET International forum of gender experts working in support of Gender equality. Development Co-operation Directorate of the Organisation for Economic Co-operation and Development (OECD). - OECD's Gender Initiative, an overview page which also links to wikiGENDER, the Gender equality project of the OECD Development Centre. - The Local A news collection about Gender equality in Sweden. - Egalitarian Jewish Services A Discussion Paper. - End The Gender Pay Gap Project based in Palo Alto, CA.
In physics, we say that a body has acceleration when there is a change in the velocity vector, either in magnitude or direction. In previous sections, we have seen that acceleration can be classified, according to the effect that it produces in the velocity, in tangential acceleration (if it changes the magnitude of the velocity vector) and in normal or centripetal acceleration (if it changes its direction). These are the intrinsic components of the acceleration. In this section, we are going to develop the concept of tangential acceleration in more detail. Previously we have seen that the instantaneous acceleration is the derivative of the velocity with respect to time. On the other hand, we have seen that we can express the velocity vector as the product of its magnitude and a unit vector tangent to the trajectory Where we have applied the derivative of a product rule D(ab)=a'b+ab'. We see that the first term ( Intrinsic components of the acceleration Tangential acceleration ( Tangential acceleration measures the rate of change of the velocity magnitude over time. It is given by the expression: : Is the tangential acceleration vector : Is the magnitude of the velocity vector : Is the unit vector that correspond to the direction of the motion on the tangent axis The value of the tangential acceleration may be: - Greater than zero (> 0): When the body has accelerated motion, that is, the magnitude of the velocity vector increases with time - Less than zero (<0): When the body has slowing or decelerated motion, that is, the magnitude of the velocity vector decreases with time - Equal to zero (= 0): When the body has uniform motion, that is, the magnitude of the velocity vector remains constant
This year has seen unprecedented wildfires cause havoc across the world. Australia recently battled its largest bushfire on record, while parts of the Arctic, the Amazon and central Asia have also experienced unusually severe blazes. It follows on from “the year rainforests burned” in 2019. Last year saw the Amazon face its third-largest fire on record, while intense blazes also raged in Indonesia, North America and Siberia, among other regions. A rapid analysis released this year found that climate change made the conditions for Australia’s unprecedented 2019-20 bushfires at least 30% more likely. Further analysis – visualised below in an interactive map – has shown that, globally, climate change is driving an increase in the weather conditions that can stoke wildfires. But despite a growing field of evidence suggesting that climate change is making the conditions for fire more likely, research finds that the total area burned by wildfires each year decreased by up to a quarter in the past two decades. Understanding this paradox requires scientists to assess a vast range of influential factors, including climate change, human land-use and political and social motivations. In this explainer, Carbon Brief examines how wildfires around the world are changing, the influence of global warming and how risks might multiply in the future. - When and where are most of the world’s wildfires? - How is climate change affecting wildfire risk? - Interactive global map which locates 73 wildfire scientific studies - Are wildfires increasing across the globe? - How will wildfires change in the future? When and where are most of the world’s wildfires? At any given time, some part of the world is on fire. The map below, from the Global Forest Watch, shows where in the world has had a fire in the past 24 hours. A “wildfire” can be defined as any type of uncontrolled fire that is spreading across wildland, including pastureland, forests, grasslands and peatlands. (Sometimes, fires are started intentionally and in a controlled manner, including during “prescribed burning”.) Globally, wildfires have many impacts on humans, wildlife and the economy. Wildfires are a major driver of greenhouse gas emissions and are also responsible for 5-8% of the 3.3 million annual premature deaths from poor air quality, research suggests. Some wildfires are started naturally, chiefly by lightning. The rest are started by humans, either accidentally or by arson. Across the world, it is estimated that just 4% of fires start naturally. However, the proportion of human-started versus lightning-started fires varies widely from region to region. For example, in the US, 84% of fires are started by humans. However, in Canada, the majority (55%) of wildfires are started by lightning. Many regions experience distinct wildfire seasons, driven by rainy and dry periods and human practices, such as agricultural burning. However, other regions have a risk of fire year-round. The animation below, which uses data from NASA’s moderate resolution imaging spectroradiometer (MODIS), shows where in the world wildfires occurred in each month of 2019. The red, orange and yellow pixels on the maps show the locations where the satellite detected actively burning fires. The colours represent a count of the number of fires observed within a 1,000-sq-km area. White pixels show as many as 30 fires in a 1,000-sq-km area per day. Orange pixels show as many as 10 fires, while red areas show as few as 1 fire in a day. The animation shows how the average timing of fire seasons differs in different world regions. North America, the Amazon, southern Africa and parts of Australia tend to see an uptick in fires from around August to late November. These months coincide with the height of the dry season in southern Africa and the Amazon. By contrast, central Africa and parts of southeast Asia see most of their fires in December through to March. This coincides with the peak of the dry season in Africa’s Sahel region, which is north of the equator. The year 2019 saw several large and – in some cases – unprecedented wildfires. The UK had a record-breaking year in terms of total area burned by fire, with most its fires occurring in February to April. In June to July, more than 100 intense fires broke out across the Arctic Circle, mostly in Alaska and Siberia. August saw the Amazon battle its third-largest fires on record, while September saw large fires in North America and Indonesia. Towards the end of the year, Australia began to face its largest bushfires on record. Australia’s unprecedented fire season continued into 2020, coming to a close at the end of March. The spring saw the return of fires to rural parts of the UK – likely boosted by an unusually hot winter, which left vegetation dry. The end of March also saw large fires break out in southwestern China, which killed at least 19 people and forced almost 25,000 more to evacuate. From March to July this year, unprecedented heat in the Arctic fanned large “zombie fires” in Siberia. The fires ripped across vast stretches of permafrost, threatening the release of millions of tonnes of long-held carbon. Analysis by Dr Mark Parrington, a senior wildfire scientist at the EU’s Copernicus Atmosphere Monitoring Service, has found that the Arctic fires seen in June 2020 were larger and more intense than those seen in June 2019. However, both the 2019 and 2020 Arctic fires are far above the average level seen in the region from 2003-18. “Will 2019 & 2020 be considered extremes? Or are we seeing the beginning of a new regime?” June 2020 also saw the return of large fires in the Amazon. This was several months before the region’s usual “fire season”, which typically runs from August to to October, says Dr Ane Alencar, director of science at the Amazon Environmental Research Institute (IPAM) in Brazil. In June, she told a press briefing: “I think it is very important and very worrisome to think about what is going to happen during this fire season.” Though fires happen all over the world, the largest and fastest-spreading fires mostly occur in sparsely populated grasslands in Australia, Africa and central Asia, according to NASA’s fire datasets. The map below, put together by NASA, shows the average size of fires across the world from 2003-16. On the map, dark red spots indicate large fires. Across all of the world’s grasslands, Africa sees the highest number of large fires, explains Thailynn Munroe, a fire research analyst at the Global Forest Watch, an open-source forest monitoring service. In fact, some researchers estimate that up to 70% of the world’s fires occur on the African continent. Munroe explains to Carbon Brief: “Most of the fires that are started in Africa are for land-clearing and agriculture. A lot of it is either clearing for pastureland in sub-Saharan Africa or for agriculture in central Africa. I think that’s why we don’t see a lot of fires in Africa in the news because it’s more just part of the way of life there.” The timing and whereabouts of fire is also influenced by the world’s major climate systems, such as El Niño, which periodically affects weather in many world regions, including southeast Asia and South America. Munroe explains: “Fires in southeast Asia are greatly impacted by El Niño. In 2015-16, there was a really strong El Niño event which brought hot and dry weather. That was one of the reasons why Indonesia had such an intense fire season in that period.” In 2015, Indonesia’s wildfires spiked, causing greenhouse gas release on the same scale as Brazil’s total annual emissions. The smoke from the fires led to 19 deaths and caused up to half a million people to suffer from respiratory illness, the Guardian reported. Fires in Indonesia have been worsened by the practice of draining peatlands. How is climate change affecting wildfire risk? There are several ways in which climate change can raise the risk of wildfires – and the importance of each of these factors varies from region to region, says Dr Cristina Santin, a wildfires researcher from Swansea University. However, in general, one of the most important ways that climate change can increase the risk of severe fires is by causing vegetation to dry out, she says. When temperatures are warmer than average, rates of evaporation increase, causing moisture to be drawn out from plants on the land. This drying can create “tinderbox conditions” – meaning that, if a fire is sparked, it can spread very quickly over large areas. Similar conditions can also be created by long periods of drought, Santin tells Carbon Brief: “In the fire community, we call vegetation that is available to burn ‘fuel’. If you have a forest, not all vegetation is considered fuel because, under normal circumstances, it’s not going to burn. But if you have a huge drought or heatwave, a lot of that vegetation will be very dry and, therefore, it will become fuel.” Such conditions occurred during the 2018 northern hemisphere heatwave, which saw all-time temperature records broken across Europe, North America and Asia. In the Attica region of Greece, wildfires ripped across large swathes of dry land at lightning speed, causing people to rush to nearby beaches and into the sea. (A study covered by Carbon Brief found that the 2018 northern-hemisphere heatwave would have been “impossible” without human-caused climate change.) Sustained hot temperatures were also a major driver of Australia’s unprecedented 2019-20 bushfires, says Dr Friederike Otto, acting director of the Environmental Change Institute at the University of Oxford. Otto co-authored an analysis finding that temperatures during the bushfires were 1C to 2C hotter than they would have been in the early 20th century. She tells Carbon Brief: “We found that climate change made the bushfires at least 30% more likely – and that is a conservative estimate. When we looked at temperatures alone, we found there has been a big increase in extreme temperatures in that region because of climate change.” As well as making fires more severe, warming temperatures are also making fire seasons longer in some regions, explains Dr Megan Kirchmeier-Young, a researcher of climate extremes at the Government of Canada. (Fire seasons are a stretch of a time when a particular region is most likely to see large and intense blazes.) She tells Carbon Brief: “Climate change is affecting wildfires in two main ways. The first is an increase in the risk or the likelihood of wildfire. The second is longer fire seasons – and this is mostly coming from warming temperatures.” A study published in 2015 found that, globally, the number of days where wildfires are likely to burn has risen as a result of climate change. The influence of climate change on fire seasonality is especially pronounced in regions that have seasonal snow cover, including parts of North America and northern Europe, she explains: “In some regions, especially in Canada, we also consider when we lose winter snow cover. With warming temperatures, that’s going to be happening earlier in the year and it will also be later in the year before we see cooler temperatures and the return of snow cover. So a longer fire season means more time of the year where you could have fires.” Research led by Kirchmeier-Young found that Canada’s 2017 fire season, which saw a record 1.2m hectares of land burned, was driven by “extreme warm and dry conditions” heightened by climate change. The study estimated that the total area burned across the season was made seven to 11 times larger by climate change. Further south, in California, a research paper published in 2020 found that the number of autumn days with weather suitable for wildfires has doubled since the 1980s as a result of climate change. The lengthening of fire seasons in California has had a knock-on effect on plant “phenology” – the timing of key events in plants’ life cycle, says Dr Frank Lake, a fire ecologist for the United States Forest Service. He tells Carbon Brief: “We have seen due to climatic change, often hotter, drier conditions in California. We’ve seen longer fire seasons, which has also affected plant phenology, and we have extended periods of drought. That has definitely dried out the fuels [vegetation] and increased fire activity.” In the Amazon, human-caused climate change and shifts to how people use the land have worked in tandem to greatly increase the risk of wildfires, says Alencar. In June, she told a press briefing: “Unlike some forests in California, Florida, or in Australia, the Amazon doesn’t burn naturally. The natural fire regime in the Amazon is said to be somewhere between 500 to 1,000 years. Our results have demonstrated that in some places in the Amazon, actually, that fire regime has changed to 12 years. So, an area that should burn naturally every 500 to 1,000 years is burning every 12.” This year, Science Brief – a UK-based web platform run by a team of scientists – released a review of 73 scientific studies finding that climate change is increasing the risk of wildfires at a global level. For the review, the scientists analysed all research papers published since 2013 that investigate the link between climate change and wildfires, either in a certain region or from a global perspective. The researchers assessed how each study compared to the statement: “Climate change increases the risk of wildfires”. Carbon Brief’s interactive map below includes each of the 73 studies, which are displayed according to what part of the world they focus on. Studies that fully support the statement that climate change increases wildfire risk are represented with a dark red icon, studies that mostly support the statement are represented in dark orange and studies that inform the statement but do not fully support it are represented in light orange.Interactive map displaying 73 studies included in Science Brief’s review on wildfires and climate change. Data source: Science Brief. Map by Tom Prater and Joe Goodman. (The software used to make the map currently only works with a Web Mercator projection – as used by virtually all major online map providers. It is worth noting that this – like all map projections – offers a somewhat distorted view of the world.) The map shows how the majority of the 73 studies published since 2013 looking into wildfires either fully or mostly support the statement that climate change is increasing the risk of wildfires. It also shows that the vast majority of regional wildfire studies have been conducted in North America, Europe and Australia – with a visible lack of studies in the fire hotspots of central Africa and southeast Asia. The review found strong evidence that climate change is making the weather conditions needed for wildfires more likely, says Dr Matthew Jones, a senior researcher of fire emissions at the University of East Anglia and lead author of the analysis. He tells Carbon Brief: “Our main focus in the ScienceBrief review was on fire weather and how it is impacted by climate change. We found unequivocal evidence – based on observations and models spanning key global regions – that anthropogenic climate change has increased the flammability of landscape fuels and placed upwards pressure on fire activity.” Among the research analysed are several “attribution” studies. “Attribution” refers to a fast-growing field of climate science that aims to quantify the “fingerprint” of climate change on extreme-weather events, such as wildfires, heatwaves and floods. (Both Otto and Kirchmeier-Young’s studies are examples of attribution, for example.) Analysis by Carbon Brief finds that, by the end of 2019, there had been 11 studies published that look into the role of climate change in single wildfire events. Out of these studies, 10 conclude that the fires analysed were made more likely or more severe by climate change. However, it is worth noting that all of these studies were carried out in either North America or Australia – with, again, no research looking into the role of climate change in fire hotspots, such as central Africa or southeast Asia. In addition, there have been relatively very few studies into the role of climate change in wildfires when compared to other extreme events. The chart below shows the number of studies that have been conducted into different types of extreme weather events, including heatwaves, floods and extreme rainfall events and droughts, among others. On the chart, colour indicates the proportion of studies that found climate change made the event more severe or more likely (red), less severe or less likely (yellow), where climate change had no effect (blue) and where there was insufficient data to draw conclusions (grey).Chart shows the number of studies for each type of extreme event that fall within each category of human influence: More severe/likely (red), less severe/likely (yellow), no influence (blue) and inconclusive (grey). Chart by Carbon Brief using Highcharts. One reason why few wildfire attribution studies have been carried out is that fire risk is affected by multiple meteorological factors, says Kirchmeier-Young. These include temperature and rainfall, but also wind speed, which can influence the pace at which fires can spread, and soil moisture, which can influence the size of wildfires. With so many different factors to consider, it can make it difficult to come up with a study framework that encompasses the whole picture of how climate change is affecting the probability and severity of a fire event, she says: “Attribution generally requires you to define the event that you’re looking at. With a heatwave, you may look at maximum temperatures over a particular area, which you can easily get from a climate model. But with fire, there are a lot more variables that come into play – such as temperatures, precipitation levels, wind speed – and that can be a little more challenging.” The complicated mix of factors affecting fire risk can also make it more difficult to source data, particularly in developing world regions, adds Otto: “You can’t really do an attribution study if you don’t have decent observations. For fire, things like wind and soil moisture are also important, and in many parts of the world you have absolutely no observations for those variables.” These challenges may have hampered efforts to carry out more wildfire attribution studies, Otto adds. Are wildfires increasing across the globe? With climate change raising the risk of hot and dry weather in many parts of the world, it may seem prudent to assume that the global area burned by wildfires each year is increasing. However, several research papers looking into wildfires at a global level have come to the opposite conclusion. A paper published in the journal Science found that, globally, the area burned by wildfires decreased by 25% between 2003 and 2015. The animation below, which uses data from the study, illustrates the pattern of how global area burned by wildfires changed over this time period. The chart shows how the global burnt area zigzags throughout a year-long period. This is likely down to the influence of dry seasons and seasonal human practices, says Munroe. (For more information see: “When and where are most of the world’s wildfires?”) However, despite peaks and troughs, an overall downward trend is seen until 2015. (And unpublished data from Global Forest Watch suggests that this downward trend continued up until 2020, Munroe says.) There are several reasons why global burnt area could be decreasing at a global level despite the effect of warming, explains Santin, who co-authored a research paper looking into this paradox in 2016. By far the most important factor is likely to be changes in how humans use the land, especially around the Sahel region of Africa, says Santin: “It’s not all about climate change. We’ve seen a decrease in global burnt area in the last couple of decades and that is mostly because of land-use change. There are areas – mainly in Africa – that used to be savannah but, because of growing human populations, have been converted to agricultural, grazing and urban land.” Savannah is a term for areas of grassland with sparse trees, which are typically found on the margins of the tropics. Such ecosystems cover half of Africa’s surface. For thousands of years, wildfires have been commonplace in African savannahs, with some native tree species evolving special characteristics in response to frequent fires, such as fire-resistant bark. However, recent years have seen an increase in the conversion of savannah to agricultural land as nations seek to feed sub-Saharan Africa’s rapidly growing population. With less wild savannah left, sub-Saharan Africa has seen a decline in the number of large wildfires, says Santin. The map below, which uses data from the Science study, illustrates how burnt area has shifted in different world regions from 2003-15. On the map, dark blue indicates a large percentage decrease in burnt area, where deep red indicates a large percentage increase. The map features a wide blue band stretching across northern sub-Saharan countries from Senegal and the Gambia to Sudan and South Sudan, indicating percentage decreases in area burned by fire in this region. This is likely down to land conversion, says Santin. Other decreases in burnt area, including in central South America, Madagascar and parts of southeast Asia may also be driven by the conversion of wildland to agricultural land, she adds. The authors of the Science paper also attribute decreases in burnt area to the conversion of savannah to agricultural land. The scientists, led by Dr Niels Andela at the NASA Goddard Space Flight Center, write: “A shift toward more capital-intensive agriculture has led to fewer and smaller fires, driven by population increases, socioeconomic development, and demand for agricultural products from regional and global markets.” Decreases in developed parts of the world, including northern Australia, could be down to improved fire management techniques, adds Munroe. In northern Australia, firefighters use “prescribed burning” – a technique pioneered by indigenous communities involving the burning of small patches of grassland early on in the dry season. This creates “fire breaks” in the landscape, which can prevent fires from quickly spreading over large areas of wildland. For centuries, Native Americans managed fire risk in woodlands using prescribed burning. However, the arrival of non-native settlers saw the use of prescribed burning decrease, causing the landscape to shift to being more dominated by trees over the past century. Lake, who is of indigenous American Indian descent, tells Carbon Brief: “At the core of the understanding of indigenous knowledge is how to live with fire.” A study published in Science in 2006 found that the accumulation of trees – also known as “fuel loading” – and human-caused climate change are both important factors in increased fire risk across the western US. Lake says: “We’ve reached a tipping point. There’s too much fuel loading and it’s now too warm, the ability of ignition is greater with both lightning and human-set fires, and now we have these much larger and more extensive fires…Almost universally tribal elders have said this is something that is unprecedented in our cultural legacy of knowledge.” It is also worth noting that human land-use change can greatly increase the area burned by wildfires. For example, recent surges in deforestation in the Amazon have been linked to greatly increased fire activity. Alencar explains: “Fires in the Amazon usually are the last stage of deforestation. It is the most inexpensive tool that people have to convert biomass into ashes so that [they can use the land] for some pasture fields.” According to NASA scientists, the Amazon’s severe 2019 fire season was “more consistent with land clearing than with regional drought”. “Slash-and-burn” clearing has also been linked to damaging peat fires in Indonesia. Fires in the country have been exacerbated further by the practice of peatland draining. In order to grow palm oil and other crops, such as timber, peatlands are often drained of their natural moisture – leaving them dry and more likely to catch alight. The influence of human land-use activity on global burnt area makes it an imperfect metric of how climate change is truly affecting wildfires, Prof Anthony Westerling a fire and drought researcher at the University of California, Merced, told Carbon Brief in 2018. Another way that scientists could study the influence of climate change is by tracking fire severity. Research published in 2017 analysed all “extreme wildfire events” from 2002-13 and found that 96% occurred during periods of hot and dry weather. (“Extreme wildfires” were deemed to be fires that caused serious economic or social damage.) However, there is little research into how fire severity has changed at a global scale in recent decades. (A string of research papers have linked increasing fire severity in North America to climate change.) How will wildfires change in the future? Climate change will continue to drive temperature rise and more unpredictable rainfall in many parts of the world, meaning that the number of days with “fire weather” – conditions in which fires are likely to burn – is expected to increase in coming decades, says Kirchmeier-Young: “As we continue to see increasing temperatures, we will continue to see an increase in the likelihood of wildfires. So, more days with increased fire risk, longer fire seasons.” A study covered by Carbon Brief found that, by the middle of the century, there could be a 35% increase in the days with a high danger of fire across the world, on average – if little action is taken to tackle climate change. The regions likely to see the highest increase in days with extreme fire weather in this very high emissions scenario (“RCP8.5”) include the western US, southeastern Australia, the Mediterranean and southern Africa, according to the study. This is highlighted on the map below, which shows the projected change in the number of days with “high” fire danger from 2000-14 to the middle of the century (2014-70). The regions with the largest increase are shaded orange and red, while the areas with decreasing risk are shown in green. Other studies have investigated how the risk of fire weather is likely to change in different world regions if the world does take action to tackle climate change. For example, a study published in 2020 found that, in California, “climate change will further amplify the number of days with extreme fire weather by the end of this century”. However if efforts are taken to limit global warming to below 2C, which is the goal of the Paris Agreement, this “would substantially curb that increase”, the authors say. In the Mediterranean, limiting global warming to 1.5C, which is the aspirational target of the Paris Agreement, could halve the total area burned by wildfires in the summer, when compared to a scenario where warming reaches 3C, according to a second study. In Australia, days with fire weather akin to that seen during the 2019-2020 bushfires could become at least four times more likely under 2C of global warming, according to Otto’s recent analysis. A landmark special report in 2018 from the Intergovernmental Panel on Climate Change (IPCC) concluded (pdf) that limiting global warming to 1.5C rather 2C would “reduce” the average wildfire risk worldwide. However, though the risk of wildfires is likely to heighten in coming decades, it is not yet clear whether the area burned by wildfires will increase correspondingly, says Santin: “It’s a complicated issue because it’s not only climate change controlling future fire risk, it’s also the interaction of humans and climate change.” It is possible that efforts by humans to suppress wildfires could stem increases in the area burned by fire, despite the increased risk posed by climate change, she says. However, it may be the case that, in some areas, the risks posed by climate change will become too large to overcome with adaptation measures, she adds: “Something interesting that we’ve seen with the recent Australian fires is that, even in areas where efforts to suppress wildfires were undertaken, the fire conditions were so crazy – the temperatures so hot, the winds so strong – that the fires burned through every protective measure.” Indeed, a research paper published in 2016 found that, globally, human efforts could suppress wildfire increases in the near future, but that these efforts may become ineffective later on in the century. The authors write: “For future scenarios, global burnt area will continue to decline under a moderate emissions scenario…but start to increase again from around mid-century under high greenhouse gas emissions.” Explainer: How climate change is affecting wildfires around the world Wildfires and climate change: what does the science say? 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Serial communications send a single bit at a time between computers. This only requires a single communication channel, as opposed to 8 channels to send a byte. With only one channel the costs are lower, but the communication rates are slower. The communication channels are often wire based, but they may also be can be optical and radio. Figure 26.2 Serial Data Standards shows some of the standard electrical connections. RS-232c is the most common standard that is based on a voltage change levels. At the sending computer an input will either be true or false. The line driver will convert a false value in to a Txd voltage between +3V to +15V, true will be between -3V to -15V. A cable connects the Txd and com on the sending computer to the Rxd and com inputs on the receiving computer. The receiver converts the positive and negative voltages back to logic voltage levels in the receiving computer. The cable length is limited to 50 feet to reduce the effects of electrical noise. When RS-232 is used on the factory floor, care is required to reduce the effects of electrical noise - careful grounding and shielded cables are often used. The RS-422a cable uses a 20 mA current loop instead of voltage levels. This makes the systems more immune to electrical noise, so the cable can be up to 3000 feet long. The RS-423a standard uses a differential voltage level across two lines, also making the system more immune to electrical noise, thus allowing longer cables. To provide serial communication in two directions these circuits must be connected in both directions. To transmit data, the sequence of bits follows a pattern, like that shown in Figure 26.3 A Serial Data Byte. The transmission starts at the left hand side. Each bit will be true or false for a fixed period of time, determined by the transmission speed. A typical data byte looks like the one below. The voltage/current on the line is made true or false. The width of the bits determines the possible bits per second (bps). The value shown before is used to transmit a single byte. Between bytes, and when the line is idle, the Txd is kept true, this helps the receiver detect when a sender is present. A single start bit is sent by making the Txd false. In this example the next eight bits are the transmitted data, a byte with the value 17. The data is followed by a parity bit that can be used to check the byte. In this example there are two data bits set, and even parity is being used, so the parity bit is set. The parity bit is followed by two stop bits to help separate this byte from the next one. Some of the byte settings are optional, such as the number of data bits (7 or 8), the parity bit (none, even or odd) and the number of stop bits (1 or 2). The sending and receiving computers must know what these settings are to properly receive and decode the data. Most computers send the data asynchronously, meaning that the data could be sent at any time, without warning. This makes the bit settings more important. Another method used to detect data errors is half-duplex and full-duplex transmission. In half-duplex transmission the data is only sent in one direction. But, in full-duplex transmission a copy of any byte received is sent back to the sender to verify that it was sent and received correctly. (Note: if you type and nothing shows up on a screen, or characters show up twice you may have to change the half/full duplex setting.) The transmission speed is the maximum number of bits that can be sent per second. The units for this is baud. The baud rate includes the start, parity and stop bits. For example a 9600 baud transmission of the data in Figure 26.3 A Serial Data Byte would transfer up to bytes each second. Lower baud rates are 120, 300, 1.2K, 2.4K and 9.6K. Higher speeds are 19.2K, 28.8K and 33.3K. (Note: When this is set improperly you will get many transmission errors, or garbage on your screen.) Serial lines have become one of the most common methods for transmitting data to instruments: most personal computers have two serial ports. The previous discussion of serial communications techniques also applies to devices such as modems. 26.1.1 RS-232[an error occurred while processing this directive] The RS-232c standard is based on a low/false voltage between +3 to +15V, and an high/true voltage between -3 to -15V (+/-12V is commonly used). Figure 26.4 Common RS-232 Connection Schemes shows some of the common connection schemes. In all methods the txd and rxd lines are crossed so that the sending txd outputs are into the listening rxd inputs when communicating between computers. When communicating with a communication device (modem), these lines are not crossed. In the modem connection the dsr and dtr lines are used to control the flow of data. In the computer the cts and rts lines are connected. These lines are all used for handshaking, to control the flow of data from sender to receiver. The null-modem configuration simplifies the handshaking between computers. The three wire configuration is a crude way to connect to devices, and data can be lost. Common connectors for serial communications are shown in Figure 26.5 Typical RS-232 Pin Assignments and Names. These connectors are either male (with pins) or female (with holes), and often use the assigned pins shown. The DB-9 connector is more common now, but the DB-25 connector is still in use. In any connection the RXD and TXD pins must be used to transmit and receive data. The COM must be connected to give a common voltage reference. All of the remaining pins are used for handshaking. The handshaking lines are to be used to detect the status of the sender and receiver, and to regulate the flow of data. It would be unusual for most of these pins to be connected in any one application. The most common pins are provided on the DB-9 connector, and are also described below. When a computer is ready to receive data it will set the CTS bit, the remote machine will notice this on the RTS pin. The DSR pin is similar in that it indicates the modem is ready to transmit data. XON and XOFF characters are used for a software only flow control scheme. Many PLC processors have an RS-232 port that is normally used for programming the PLC. Figure 26.6 Serial Output Using Ladder Logic shows a PLC connected to a personal computer with a Null-Modem line. It is connected to the channel 0 serial connector on the PLC processor, and to the com 1 port on the computer. In this example the terminal could be a personal computer running a terminal emulation program. The ladder logic below will send a string to the serial port channel 0 when A goes true. In this case the string is stored is string memory ’example’ and has a length of 4 characters. If the string stored in example is "HALFLIFE", the terminal program will display the string "HALF". 26.1.2 ASCII Functions[an error occurred while processing this directive] ASCII functions allow programs to manipulate strings in the memory of the PLC. The basic functions are listed in Figure 26.7 PLC ASCII Functions. In the example in Figure 26.8 An ASCII String Example, the characters "Hi " are placed into string memory str_in. The ACB function checks to see how many characters have been received, and are waiting in channel 0. When the number of characters equals 2, the ARD (Ascii ReaD) function will then copy those characters into memory str_0, and bit real_ctl.DN will be set. This done bit will cause the two characters to be concatenated to the "Hi ", and the result written back to the serial port. So, if I typed in my initial "HJ", I would get the response "HI HJ". The ASCII functions can also be used to support simple number conversions. The example in Figure 26.9 A String to Integer Conversion Example will convert the strings in str_a and str_b to integers, add the numbers, and store the result as a string in str_c. Many of the remaining string functions are illustrated in Figure 26.10 String Manipulation Functions. When A is true the ABL and ACB functions will check for characters that have arrived on channel 1, but have not been retrieved with an ARD function. If the characters "ABC<CR>" have arrived (<CR> is an ASCII carriage return) the ACB would count the three characters, and store the value in cnt_1.POS. The ABL function would also count the <CR> and store a value of four in cnt_2.POS. If B is true, and the string in str_a is "ABCDEFGHIJKL", then "EF" will be stored in str_b. The last function will compare the strings in str_c and str_d, and if they are equal, output string_match will be turned on.
Whole numbers and number theory. Free printable grade 5 math worksheets. There are also opportunities to simulate real world experiences with activities that challenge kids to calculate percentages for sales tax and discounts as well as determine the area. Fifth grade math worksheets 5th grade multiplication. Worksheets math grade 5 multiplication division multiply in parts. Fifth graders will appreciate the chance to practice recalling multiplication facts and putting those skills to use. Worksheets math grade 5. To help fifth graders practice multiplying and dividing walk them through different multiplication facts and timed drills with these math worksheets. They also practice mental multiplications prime factorization order of operations and solve simple equations. These fifth grade worksheets cover multi digit multiplication multiplying with decimals multiplying decimals with models multiplication of fractions and more. Multiplication and division of fractions and mixed numbers. In grade 5 students continue studying multi digit multiplication with more digits than in 4th grade. This math worksheet reviews multiplication facts for numbers 0 10. Our grade 5 math worksheets cover the 4 operations fractions and decimals at a greater level of difficulty than previous grades. Students should attempt to answer these questions in their heads without writing down intermediary steps. The worksheets can be. These grade 5 worksheets begin with multiplying and dividing fractions by whole numbers and continue through mixed number operations all worksheets are printable pdf documents. Grade 5 multiplication worksheets. 5th grade multiplication worksheets. Fifth grade math worksheets here is a collection of our printable worksheets for topic properties of multiplication of chapter multiplication in section whole numbers and number theory. Properties of multiplication. Multiply 1 digit by 2 digit numbers. Below you can make an unlimited supply of worksheets for these topics. Worksheets math grade 5 fractions multiplication division. 5th grade multiplication facts printable worksheets. We also introduce variables and expressions into our word problem worksheets all worksheets are printable pdf documents. Below are six versions of our grade 5 math worksheet on multiplying 1 digit 1 9 by 2 digit 10 99 numbers. 5th grade multiplication and division worksheets including multiplying in parts multiplication in columns missing factor questions mental division division with remainders long division and missing dividend or divisor problems. In these multiplication worksheets students will learn and practice multiplying multi digit numbers fractions and implementing division into multiplication equations. Pin by on multiplication 5th grade math worksheets pdf download 5 348753 k5 learning math worksheets wolfacher info 348754 math fun sheets 5th grade fun math worksheets for middle school. These review worksheets.
Three central appeals are discussed in rhetoric, established by the philosopher Aristotle and sometimes called the rhetorical triangle: logos, ethos, and pathos. Logos , or the logical appeal, refers to the use of reasoned argument to persuade. This is the dominant approach in academic writing , where arguments are built up using reasoning and evidence. Ethos , or the ethical appeal, involves the author presenting themselves as an authority on their subject. For example, someone making a moral argument might highlight their own morally admirable behavior; someone speaking about a technical subject might present themselves as an expert by mentioning their qualifications. This might involve speaking in a passionate way, employing vivid imagery, or trying to provoke anger, sympathy, or any other emotional response in the audience. These three appeals are all treated as integral parts of rhetoric, and a given author may combine all three of them to convince their audience. In rhetoric, a text is not necessarily a piece of writing though it may be this. A text is whatever piece of communication you are analyzing. This could be, for example, a speech, an advertisement, or a satirical image. In these cases, your analysis would focus on more than just language—you might look at visual or sonic elements of the text too. The context is everything surrounding the text: Who is the author or speaker, designer, etc. Who is their intended or actual audience? When and where was the text produced, and for what purpose? Looking at the context can help to inform your rhetorical analysis. For example, Martin Luther King, Jr. These arguments are built up with claims, supports, and warrants. A claim is the fact or idea the author wants to convince the reader of. An argument might center on a single claim, or be built up out of many. Claims are usually explicitly stated, but they may also just be implied in some kinds of text. The author uses supports to back up each claim they make. These might range from hard evidence to emotional appeals—anything that is used to convince the reader to accept a claim. The warrant is the logic or assumption that connects a support with a claim. Outside of quite formal argumentation, the warrant is often unstated—the author assumes their audience will understand the connection without it. We can see a claim and a support here, but the warrant is implicit. Here, the warrant is the assumption that more likeable candidates would have inspired greater turnout. We might be more or less convinced by the argument depending on whether we think this is a fair assumption. Instead, it starts with looking at the text in detail and asking the appropriate questions about how it works:. See an example. Like all essays, a rhetorical analysis begins with an introduction. Martin Luther King, Jr. Delivered in to thousands of civil rights activists outside the Lincoln Memorial in Washington, D. Each paragraph should focus on a different element of the text, and they should all contribute to your overall argument for your thesis statement. The conclusion of a rhetorical analysis wraps up the essay by restating the main argument and showing how it has been developed by your analysis. It may also try to link the text, and your analysis of it, with broader concerns. By framing contemporary upheavals as part of a prophecy whose fulfillment will result in the better future he imagines, King ensures not only the effectiveness of his words in the moment but their continuing resonance today. The goal of a rhetorical analysis is to explain the effect a piece of writing or oratory has on its audience, how successful it is, and the devices and appeals it uses to achieve its goals. Essays on Aristotle's Rhetoric offers a fresh and comprehensive assessment of a classic work. Aristotle's influence on the practice and theory of rhetoric, as it affects political and legal argumentation, has been continuous and far-reaching. This anthology presents Aristotle's Rhetoric in its original context, providing examples of the kind of oratory whose success Aristotle explains and analyzes. The contributors—eminent philosophers, classicists, and critics—assess the role and the techniques of rhetorical persuasion in philosophic discourse and in the public sphere. They connect Aristotle's Rhetoric to his other work on ethics and politics, as well as to his ideas on logic, psychology, and philosophy of language. \|Rhetoric essays\|\|A good place to start is fresh graduate finance resume sample answer each of these considerations in a sentence or two on a scratch piece of paper. This damages the strength of her credibility and her argument. Uses amplification to describe and display the idiocy of practices like teeth whitening. Rhetoric Words 2 Pages. Just to be clear, your goal is not to add your opinions on the topics or dive into your standpoint or point of view on the subject. This ebook is an essay writing guide that takes you step by step through the process, from making a complete outline to finding credible sources, writing strong body paragraphs, and more. This is a lot to take in.\| \|Rhetoric essays\|\|Esl college essay ghostwriting site usa\| \|Write my film studies dissertation introduction\|\|Rhetoric In Rhetoric Words 3 Pages. A step-by-step guide to literary analysis Literary analysis means closely studying a text and discussing how meaning is conveyed through things like imagery, tone and perspective. Who is their intended or actual audience? Page 1 of how to write dubstep - About essays. This damages the strength of her credibility and her argument. For example, going back to Martin Luther King, Jr. The contributors—eminent philosophers, classicists, and critics—assess the role and the techniques of rhetorical persuasion in philosophic discourse and in the public sphere.\| \|Sample resume publisher\|\|838\| \|Ap biology essay\|\|In this handout we will use the word rhetorician to refer to the author of a speech or document or to the creator of an advertisement, cartoon, or other visual work. In rhetoric, a text is not necessarily a piece of writing though it may be this. It is the most common essay type at rhetoric essays. What does it mean in the real world? Who is their intended or actual audience? Tone: The tone is the attitude or atmosphere that the author takes in rhetoric essays writing, and it plays a pretty big role in how you feel while reading.\| Indira Sapkota Data Entry Officer. Another vital trick to consider not help you. Narbada Sorali Magar Project Manager. Neelam Tamang Assistant Hostel warden. The following are some of while picking the topic is. Choosing something not to have the tips to consider while impress upon the reader that. The fundamental trick of making writing impressive and exciting is resume writing retail experience focus on how to write dubstep topic discuss and explain in your. Gather knowledge about the rhetorical devices and literary critics used pick the topic that catches topic for your essay. Visual rhetorical analysis essay examples provide insight into the writing. Remember that you need to the article refers to her style of the author while little knowledge about it.A rhetorical analysis is a type of essay that looks at a text in terms of rhetoric. This means it is less concerned with what the author is. Free Essays from Help Me \| Rhetoric is, in my understanding, the art of persuading an audience by adapting your argument and the way you present it to. Rhetorical Analysis Sample Essay. Harriet Clark. Ms. Rebecca Winter. CWC 13 Feb. 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PreK - 2 15 min - 1 hr For 4.5 billion years, the Sun has generated energy to power the solar system. Visible light is the most obvious form of that energy. Every day the Earth turns, and the new day starts with sunlight. Here on Earth, the Sun’s light causes day and night, shadows, eclipses, and seasons. As the Earth moves on its journey around the Sun, the people on Earth experience changes in light. You experience those changes all the time. Have you ever noticed that the days are longer in summer, that it‘s colder in winter, or that your shadow practically disappears at noon? These natural phenomena are caused by the movement of the Earth around the Sun. With a little know-how, you can use some simple experiments to track those movements and model them. Can’t wait to get started? Jump to the experiment! Changing Light And Shadows The Earth is moving in space, so the light from the Sun doesn’t shine on it the same way every minute of every day. Over a year, the planet revolves around the Sun, moving along its elliptical orbit. Because of the shape of that orbit, there are times when Earth is closer to the Sun and times it is farther away. You may be tempted to assume that when the Earth is closest to the Sun, we experience summer, but that’s not how it works. In reality, it’s all about the Earth’s 23.5 degree tilt on its axis. Days And Years That tilted axis is essential to the seasons. Because of that tilt and the shape of Earth’s orbit, different parts of the planet receive the Sun’s most direct rays at different times of the year. When the North Pole tilts towards the Sun, the Northern Hemisphere gets the most direct rays of light, absorbs more energy which becomes heat, and experiences summer. When the North Pole tilts away from the Sun, the light is more indirect, causing winter. In addition, the part of the Earth that tilts towards the Sun receives more hours of sunlight during the day than the part tilted away from the Sun. You can model this at home. Take a flashlight, turn it on, and point it straight toward a wall. You get a concentrated bright light on a small area of the wall. When you tilt the flashlight a bit, the light spreads out. It’s the same amount of light, but because it’s spread over a larger area, it looks dimmer. Because the light is less concentrated, less energy is absorbed, and less heat is generated. That’s winter. Meanwhile, it takes 24 hours for the Earth to complete one rotation on its axis. That means the Earth spins, a bit like a tilted toy top. This rotation exposes parts of the Earth to sunlight as it turns. When a part of the Earth faces the Sun, it experiences day. As that part of the Earth turns away from the Sun, it experiences night. The part of the Earth nearest the Sun at any moment gets the most direct sunlight. Sometimes that light gets blocked. You see this every time you observe your shadow or stand under the shade of a tree. Because the Earth rotates, the angle of that tree relative to the Sun changes during the day. So the size and direction of the shadow change too. Really Big Shadows Shadows play a role in eclipses as well. An eclipse happens when a planet or moon gets in the way of the Sun’s light. In the case of a lunar eclipse, the Earth moves between the Sun’s light and the Moon. The Earth’s shadow covers the Moon. Because the moon’s orbit is tilted, we don’t get an eclipse every month, but they are more common than solar eclipses. For a solar eclipse, the Moon gets between the Sun’s light and the Earth. That causes it to get dark during the day. A total solar eclipse happens somewhere on Earth about every year and a half. However, the Moon’s shadow on Earth isn’t that big, so you need to be in just the right place to see a solar eclipse. That makes them very special. The next total solar eclipse in the United States will happen on April 8, 2024. We may need to wait a while to experience another eclipse, but we can explore shadows and light any day of the year. So grab your materials and get ready to experiment with light! - Tape Measure - Compass or GPS app (optional) - Lamp or flashlight (optional) Safety and clean-up notes: Never look directly at the sun while doing any of these activities! It can seriously hurt your eyes. While outside, take care to be aware of your surroundings. Tracking Visible Light Across Time It’s best to perform shadow tracing outdoors on a sunny day. You will need a safe, clean, dry, and open space of pavement or concrete for your work. Since you’ll need to visit the location several times during the day, ensure the area will be available. If you cannot draw on the ground, you can lay down newspaper, cardboard or a dropcloth instead. Use masking tape, rocks, or other easily removed materials rather than chalk to mark the shadow if needed. Even if you don’t have helpers, you can still do these activities. Just find a doll, a vase, or some other tall opaque item to substitute as a person in this activity. Activity 1: Shadow Tracing Over Time - Find a safe, clean, open space of pavement or concrete that you can visit several times throughout the day. Plan to visit at least three times during the day—morning, midday, and afternoon—so that you can trace a shadow. - Select who will be the Shadow Maker and the Shadow Tracer. - Starting in the morning, draw a box on the ground using chalk. - Have the Shadow Maker stand in the box with their back to the Sun. If using a compass or GPS, have the Shadow Maker stand facing west. Make sure they stand in a comfortable position that they can repeat in the future. - Using the chalk, have the Shadow Tracer outline the shadow of the Shadow Maker. Write the time of day by the head of the shadow. - Use your tape measure to measure the length of the shadow starting from the edge of the box you drew to the top of the head. Write the number next to the head. - Repeat the shadow tracing at least twice more. - Record all your data in a notebook or take a picture of your tracings. After making the first tracing make a prediction. Do you think the shadow will be in the same place when you next check? Why do you think that is? Once you have completed your tracings, take a look at them. - Is there a pattern to the tracings? - Is the shadow the same length in inches as your height? - At what time of day is the shadow the longest? At what time is it the shortest? - Is the shadow always pointing in the same direction? Why do you think that is? - How can shadows on the ground tell you where the Sun is in the sky? - When the Sun goes down at night, what happens to your shadow? Why? One way scientists analyze data is to summarize it by making a visual representation of the data. For example, you could create a line graph to show the change in your shadow over time. The x-axis, the horizontal line, could be the time of day, and the y-axis, the vertical line, could be the height of the shadow. Does your graph show any patterns or trends? Compare your chart with others if possible. If you do not have an appropriate place to perform your shadow tracing outside, that’s ok! Using a lamp or flashlight to model the Sun, you can simulate the process indoors. For this activity, you will need three people—the Shadow Maker, the Shadow Tracer, and the Light Holder. As the Earth rotates on its axis each day, the Sun appears to follow an arched path across the sky, traveling from east to west. From our reference point on Earth, the Sun looks like it’s moving around the Earth. It’s important to remember that the apparent movement of the Sun is actually due to the motion of the Earth. This video shows the sun’s apparent movement in the sky over the course of 12 hours. Activity 2: Shadow Tracing Indoors - Have the Shadow Maker stand in the box with their back to the light holder. Make sure the Shadow Maker stands in a comfortable position that they can hold. - Have the Light Holder stand about two feet to the right of the Shadow Maker and hold the light facing the Shadow Maker’s back. Hold the light at roughly the shoulder height of the Shadow Maker. - Next, the Shadow Tracer should outline the Shadow Maker’s shadow. Label this tracing as “morning.” Measure the shadow using your tape measure. - Repeat the shadow tracing. This time have the Light Holder stand directly behind the Shadow Maker, with the light at least the height of the Shadow Maker’s head. Label this as “noon” and measure the shadow. - For the third tracing, repeat step 2 but have the light holder to the left of the shadow maker. Label this as afternoon and measure the shadow. - You can add additional tracings, testing other places along the arc. As you moved the light, what happened to the shadow? How does this model the apparent movement of the Sun across the sky? In what ways is this simulation limited? Even if you can go outdoors for Activity 1, performing Activity 2 as a follow-up provides an opportunity to think about the Sun’s apparent movement across the sky by directly simulating it with a flashlight. What other ways can you use this technique to model other phenomena, such as an eclipse? Use What You’ve Learned Now that you’ve traced and tracked shadows throughout the day, try using what you’ve learned to make a sundial. People have been tracking the sun’s apparent movement across the sky for thousands of years. Long before we had watches, clocks, and calendars, people used the placement of the Sun as a way to tell time and track the seasons. You can do the same with simple supplies from around the house and this tutorial from Sky & Telescope. Or learn more about how places like England’s Stonehenge, Machu Picchu’s Temple of Sun, and New Mexico’s Sun Dagger were used to track important solar events by building your own Sun tracker. Keep Learning And Sharing The last total solar eclipse in the US was in 2017. The next is coming up in 2024. Start planning now with Science Friday articles and activities to help you become an eclipse expert and view the eclipse safely. Want to keep learning about light? Try What Makes Day and Night by Franklyn M. Branley. If you discover a great book, make sure you share your recommendation with Science Friday. We’d love to see your satellite models too. Share photos of your project with the hashtag #SciFriSunCamp on social media or send them to email@example.com. - 1-PS4-2: Make observations to construct an evidence-based account that objects in darkness can be seen only when illuminated. - 1-PS4-3: Plan and conduct investigations to determine the effect of placing objects made with different materials in the path of a beam of light. - 1-ESS1-1: Use observations of the sun, moon, and stars to describe patterns that can be predicted. - K-2-ETS1-1: Ask questions, make observations, and gather information about a situation people want to change to define a simple problem that can be solved through the development of a new or improved object or tool. - 3-5-ETS1-3: Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved. This activity is supported by the NASA Heliophysics Activation Team (NASA HEAT), part of NASA’s Science Activation portfolio. Written by Sandy Roberts. Edited by Ariel Zych. Illustration by Carrie Lapolla. Digital Production by Sandy Roberts. Meet the Writer About Sandy Roberts@KaleidoscopeSci Sandy Roberts is Science Friday’s Education Program Manager, where she creates learning resources and experiences to advance STEM equity in all learning environments. Lately, she’s been playing with origami circuits and trying to perfect a gluten-free sourdough recipe.
Precalculus: Relations and Functions - Module 1: Basics and Common Functions - Functions help to study the relationship between two or more variables. They are the basic quantitative tool used to visualize, analyze, and interpret these relationships. Studying functions is the first step in developing analytics skills for mathematical modeling. In this module, we develop the concept of a function and review important algebraic operations on functions used later in this course. We will also study the important features, like domain, range, and end behavior of graphs. - Module 2: Equations of Lines, Quadratics, and More Functions - In this module, we will study two common types of functions: linear and quadratic. We will learn how to identify common features of their graphs, and see how they can be used to model real world situations, particularly those involving revenue and cost. We will also further explore function compositions, and learn how to find the inverse of a function. - Module 3: Exponential and Logarithmic Functions - In this module, we expand our catalog of functions to study two new functions that arise when modelling natural phenomena: the exponential and logarithmic functions. In the last module, we saw that one-to-one functions have inverses, which reverse the function process. For example, the function f(x) = x^3 has as its inverse the function g(x) = x^(1/3). We now want to expand this process to find inverses for exponential functions - those of the form f(x) = a^x, where a is a positive number not equal to one. - Module 4: Properties of Logarithms - Understanding the logarithm as an exponent allows for important algebraic properties of the logarithm. In this module, we will explore these properties and their uses as we apply logarithms to real world examples.
Uranium ore deposits are economically recoverable concentrations of uranium within the Earth's crust. Uranium is one of the more common elements in the Earth's crust, being 40 times more common than silver and 500 times more common than gold. It can be found almost everywhere in rock, soil, rivers, and oceans. The challenge for commercial uranium extraction is to find those areas where the concentrations are adequate to form an economically viable deposit. The primary use for uranium obtained from mining is in fuel for nuclear reactors. Globally, the distribution of uranium ore deposits is widespread on all continents, with the largest deposits found in Australia, Kazakhstan, and Canada. To date, high-grade deposits are only found in the Athabasca Basin region of Canada. Uranium deposits are generally classified based on host rocks, structural setting, and mineralogy of the deposit. The most widely used classification scheme was developed by the International Atomic Energy Agency (IAEA) and subdivides deposits into 15 categories. Uranium is a silvery-gray metallic weakly radioactive chemical element. It has the chemical symbol U and atomic number 92. The most common isotopes in natural uranium are 238U (99.27%) and 235U (0.72%). All uranium isotopes present in natural uranium are radioactive and fissionable, and 235U is fissile (will support a neutron-mediated chain reaction). Uranium, thorium, and potassium are the main elements contributing to natural terrestrial radioactivity. Uranium has the highest atomic weight of the naturally occurring elements and is approximately 70% denser than lead, but not as dense as tungsten, gold, platinum, iridium, or osmium. It is always found combined with other elements. Along with all elements having atomic weights higher than that of iron, it is only naturally formed in supernova explosions. The primary uranium ore mineral is uraninite (UO2) (previously known as pitchblende). A range of other uranium minerals can be found in various deposits. These include carnotite, tyuyamunite, torbernite and autunite. The davidite-brannerite-absite type uranium titanates, and the euxenite-fergusonite-samarskite group are other uranium minerals. A large variety of secondary uranium minerals are known, many of which are brilliantly coloured and fluorescent. The most common are gummite, autunite (with calcium), saleeite (magnesium) and torbernite (with copper); and hydrated uranium silicates such as coffinite, uranophane (with calcium) and sklodowskite (magnesium). \|Primary uranium minerals\| \|uraninite or pitchblende\|\|UO2\| \|Secondary uranium minerals\| \|autunite\|\|Ca(UO2)2(PO4)2 x 8-12 H2O\| \|carnotite\|\|K2(UO2)2(VO4)2 x 1–3 H2O\| \|gummite\|\|gum like amorphous mixture of various uranium minerals\| \|saleeite\|\|Mg(UO2)2(PO4)2 x 10 H2O\| \|torbernite\|\|Cu(UO2)2(PO4)2 x 12 H2O\| \|tyuyamunite\|\|Ca(UO2)2(VO4)2 x 5-8 H2O\| \|uranocircite\|\|Ba(UO2)2(PO4)2 x 8-10 H2O\| \|uranophane\|\|Ca(UO2)2(HSiO4)2 x 5 H2O\| \|zeunerite\|\|Cu(UO2)2(AsO4)2 x 8-10 H2O\| There are several themes of uranium ore deposit formation, which are caused by geological and chemical features of rocks and the element uranium. The basic themes of uranium ore genesis are host mineralogy, reduction-oxidation potential, and porosity. Uranium is a highly soluble, as well as a radioactive, heavy metal. It can be easily dissolved, transported and precipitated within ground waters by subtle changes in oxidation conditions. Uranium also does not usually form very insoluble mineral species, which is a further factor in the wide variety of geological conditions and places in which uranium mineralization may accumulate. Uranium is an incompatible element within magmas, and as such it tends to become accumulated within highly fractionated and evolved granite melts, particularly alkaline examples. These melts tend to become highly enriched in uranium, thorium and potassium, and may in turn create internal pegmatites or hydrothermal systems into which uranium may dissolve. IAEA Classification (1996)Edit The International Atomic Energy Agency (IAEA) assigns uranium deposits to 15 main categories of deposit types, according to their geological setting and genesis of mineralization, arranged according to their approximate economic significance. - Unconformity-related deposits - Sandstone deposits - Quartz-pebble conglomerate deposits - Breccia complex deposits - Vein deposits - Intrusive deposits (Alaskites) - Phosphorite deposits - Collapse breccia pipe deposits - Volcanic deposits - Surficial deposits - Metasomatite deposits - Metamorphic deposits - Black shale deposits - Other types of deposits The IAEA classification scheme works well, but is far from ideal, as it does not consider that similar processes may form many deposit types, yet in a different geological setting. The following table groups the above deposit types based on their environment of deposition. \|Uranium Deposit Classification\| \|Uranium Transport / \|Surface Processes / synsedimentary\|\|Surficial deposits\| \|Quartz-pebble conglomerate deposits\| \|Diagenetic – Hydrothermal?\|\|Unconformity-related deposits\| \|Collapse breccia pipe deposits\| \|Magmatic – Hydrothermal?\|\|Breccia complex deposits\| \|Metamorphic – Hydrothermal?\|\|Metamorphic deposits\| Deposit types (IAEA Classification)Edit Unconformity-type uranium deposits host high grades relative to other uranium deposits and include some of the largest and richest deposits known. They occur in close proximity to unconformities between relatively quartz-rich sandstones comprising the basal portion of relatively undeformed sedimentary basins and deformed metamorphic basement rocks. These sedimentary basins are typically of Proterozoic age, however some Phanerozoic examples exist. Phanerozoic unconformity-related deposits occur in Proterozoic metasediments below an unconformity at the base of overlying Phanerozoic sandstone. These deposits are small and low-grade (Bertholene and Aveyron deposits, in France). The highest grade uranium deposits are found in the Athabasca Basin in Canada, including the two largest high grade uranium deposits in the world, Cigar Lake with 217 million pounds (99,000 t) U3O8 at an average grade of 18% and McArthur River with 324 million pounds (147,000 t) U3O8 at an average grade of 17%. These deposits occur below, across and immediately above the unconformity. Additionally, another high grade discovery is in the development stage at Patterson Lake (Triple R deposit) with an estimated mineral resource identified as; "Indicated Mineral Resources" estimated to total 2,291,000 tons at an average grade of 1.58% U3O8 containing 79,610,000 pounds of U3O8. "Inferred Mineral Resources" are estimated to total 901,000 tons at an average grade of 1.30% U3O8 containing 25,884,000 pounds of U3O8. http://www.fissionuranium.com/_resources/reports/RPA_Fission_U_Patterson_Lake_South_Technical_Report_FINAL_Feb_2015.pdf The deposits of the McArthur River basin in the East Alligator Rivers region of the Northern Territory of Australia (including Jabiluka, Ranger, and Nabarlek) are below the unconformity and are at the low-grade end of the unconformity deposit range but are still high grade compared to most uranium deposit types. There has been very little exploration in Australia to locate deeply concealed deposits lying above the unconformity similar to those in Canada. It is possible that very high grade deposits occur in the sandstones above the unconformity in the Alligator Rivers/Arnhem Land area. Sandstone deposits are contained within medium to coarse-grained sandstones deposited in a continental fluvial or marginal marine sedimentary environment. Impermeable shale or mudstone units are interbedded in the sedimentary sequence and often occur immediately above and below the mineralised horizon. Uranium is mobile under oxidising conditions and precipitates under reducing conditions, and thus the presence of a reducing environment is essential for the formation of uranium deposits in sandstone. Primary mineralization consists of pitchblende and coffinite, with weathering producing secondary mineralization. Sandstone deposits constitute about 18% of world uranium resources. Orebodies of this type are commonly low to medium grade (0.05–0.4% U3O8) and individual orebodies are small to medium in size (ranging up to a maximum of 50,000 t U3O8). Sandstone hosted uranium deposits are widespread globally and span a broad range of host rock ages. Some of the major provinces and production centers include: This model type can be further subdivided into the following sub-types: - roll front - basal channel - structurally related Many deposits represent combinations of these types. Tabular deposits consist of irregular tabular or elongate lenticular zones of uranium mineralisation within selectively reduced sediments. The mineralised zones are oriented parallel to the direction of groundwater flow, but on a small scale the ore zones may cut across sedimentary features of the host sandstone. Deposits of this nature commonly occur within palaeochannels cut in the underlying basement rocks. Tabular sandstone uranium deposits contains many of the highest grades of the sandstone class, however the average deposit size is very small. Roll-front uranium deposits are generally hosted within permeable and porous sandstones or conglomerates. The mechanism for deposit formation is dissolution of uranium from the formation or nearby strata and the transport of this soluble uranium into the host unit. When the fluids change redox state, generally in contact with carbon-rich organic matter, uranium precipitates to form a 'front'. The Rollfront subtype deposits typically represent the largest of the sandstone-hosted uranium deposits and one of the largest uranium deposit types with an average of 21 million lb (9,500 t) U3O8. Included in this class are the Inkai deposit in Kazakhstan and the Smith Ranch deposit in Wyoming. Probably more significant than their larger size, rollfront deposits have the advantage of being amenable to low cost in-situ leach recovery. - roll-front deposits are crescent-shaped bodies that transect the host lithology - typically the convex side points down the hydraulic gradient. - the limbs or tails tend to be peneconcordant with the lithology. - most ore-bodies consist of several interconnected rolls. - individual roll-front deposits are quite small but collectively can extend for considerable distances. Basal channel (palaeochannel)Edit Basal channel deposits are often grouped with tabular or rollfront deposits, depending on their unique characteristics. The model for formation of palaeochannel deposits is similar to that for roll-front deposits, above, except that the source of uranium may be in the watershed leading into a stream, or the bed load of the palaeochannel itself. This uranium is transported through the groundwaters and is deposited either at a reduced boundary, or in ephemeral drainage systems such as those in deserts of Namibia and Australia, it is deposited in calcretised evaporation sites or even in saline lakes as the ground water evaporates. Some particularly rich uranium deposits are formed in palaeochannels which are filled in the lower parts by lignite or brown coal, which acts as a particularly efficient reductive trap for uranium. Sometimes, elements such as scandium, gold and silver may be concentrated within these lignite-hosted uranium deposits. The Frome Embayment in South Australia hosts several deposits of this type including Honeymoon, Oban, Beverley and [Four-Mile] (which is the largest deposit of this class). These deposits are hosted in palaeochannels filled with Cainozoic sediments and sourced their uranium from uranium-rich Palaeo- to Mesoproterozoic rocks of the Mount Painter Inlier and the Olary Domain of the Curnamona Province. Tectonic-lithologic controlled uranium deposits occur in sandstones adjacent to a permeable fault zone which cuts the sandstone/mudstone sequence. Mineralisation forms tongue-shaped ore zones along the permeable sandstone layers adjacent to the fault. Often there are a number of mineralised zones 'stacked' vertically on top of each other within sandstone units adjacent to the fault zone. Quartz-pebble conglomerate depositsEdit Quartz pebble conglomerate hosted uranium deposits are of historical significance as the major source of primary production for several decades after World War 2. This type of deposit has been identified in eight localities around the world, however the most significant deposits are in the Huronian Supergroup in Ontario, Canada and in the Witwatersrand Supergroup of South Africa. These deposits make up approximately 13% of the world's uranium resources. Two main sub-types have been identified: Quartz pebble conglomerate hosted uranium deposits formed from the transport and deposition of uraninite in a fluvial sedimentary environment and are defined as stratiform and stratabound paleoplacer deposits. Host rocks are typically submature to supermature, polymictic conglomerates and sandstones deposited in alluvial fan and braided stream environments. The host conglomerates of the Huronian deposits in Canada are situated at the base of the sequence, whereas the mineralized horizons in the Witwatersand are arguably along tectonized intraformational unconformities. Uranium minerals were derived from uraniferous pegmatites in the sediment source areas. These deposits are restricted to the Archean and early Paleoproterozoic and do not occur in sediments younger than about 2200 million years when oxygen levels in the atmosphere reached a critical level, making simple uranium oxides no longer stable in near-surface environments. Quartz pebble conglomerate uranium deposits are typically low grade but characterized by high tonnages. The Huronian deposits in Canada generally contain higher grades (0.15% U3O8) and greater resources (as shown by the Denison and Quirke mines), however some of the South African gold deposits also contain sizeable low grade (0.01% U3O8) uranium resources. In the Witwatersrand deposits ores are found along unconformities, shale and siltstone beds, and carbonaceous seams. The West Rand Group of sediments tend to host the most uranium within the Witwatersrand Supergroup. The uranium rich Dominion Reef is located at the base of the West Rand Supergroup. The Vaal Reef is the most uranium rich reef of the Central Rand Group of sediments. Structural controls on the regional scale are normal faults while on the deposit scale are bedding parallel shears and thrusts. Textural evidence indicates that the uranium and gold have been remobilized to their current sites; however the debate continues if the original deposition was detrital or was entirely hydrothermal, or alternatively related to high grade diagenesis. Uranium minerals in the Witwatersrand deposits are typically uraninite with lesser uranothorite, brannerite, and coffinite. The uranium is especially concentrated along thin carbonaceous seams or carbon leaders. Strong regional scale alteration consists of pyrophyllite, chloritoid, muscovite, chlorite, quartz, rutile, and pyrite. The main elements associated with the uranium are gold and silver. Gold contents are much higher than in the Elliot Lake type with U:Au ranging between 5:1 and 500:1, which indicates that these gold-rich ores are essentially very low grade uranium deposits with gold. Elliot Lake sub-typeEdit Sedimentological controls on the Huronian deposits of the Elliot Lake district appear to be much stronger than in the Witwatersrand deposits. Ores grade from uranium through thorium to titanium-rich with decreasing pebble size and increasing distance from their source. While evidence of post-diagenetic remobilization has been identified, these effects appear far subordinate to the sedimentological controls. Ore consists of uraninite with lesser brannerite and thucholite. These occur in thin beds exhibiting graded bedding reminiscent of placer sorting. Alteration is nonexistent to very weak at best and the weak chlorite and sericite are believed to be mainly post-ore effects. Other post-depositional alteration includes pyritization, silicification, and alteration of titanium minerals. The most prominent geochemical associations with the uranium are thorium and titanium. This schematic model represents the original depositional setting. The Huronian underwent mild post-depositional folding during the Penokean orogeny around 1.9 billion years. The main regional structure is the Quirke syncline along the margins of which the majority of the known deposits are situated. Due to this structural overprint ore bodies range from subhorizontal to steeply dipping. Breccia complex deposits (IOCG-U)Edit Only one iron-ore-copper-gold (IOCG) deposit of this type is known to contain economically significant quantities of uranium. Olympic Dam in South Australia is the world's largest resource of low-grade uranium and accounts for about 66% of Australia's reserves plus resources. Uranium occurs with copper, gold, silver, and rare earth elements (REE) in a large hematite-rich granite breccia complex in the Gawler Craton overlain by approximately 300 metres of flat-lying sedimentary rocks of the Stuart Shelf geological province. Another example for the Breccia type is the Mount Gee area in the Mount Painter Inlier, South Australia. Uranium mineralised quartz-hematite breccia is related to Palaeoproterozoic granites with uranium contents of up to 100 ppm. Hydrothermal processes at about 300 million years ago remobilised uranium from these granites and enriched them in the quartz-hematite breccias. The breccias in the area host a low grade resource of about 31,400 t U3O8 at 615 ppm in average. Vein deposits play a special role in the history of uranium: the term "pitchblende" ("Pechblende") originates from German vein deposits when they were mined for silver in the 16th century. F.E. Brückmann made the first mineralogical description of the mineral in 1727 and the vein deposit Jachymov in the Czech Republic became the type locality for uraninite. In 1789 the German chemist M. H. Klaproth discovered the element of uranium in a sample of pitchblende from the Johanngeorgenstadt vein deposit. The first industrial production of uranium was made from the Jachymov deposit and Marie and Pierre Curie used the tailings of the mine for their discovery of polonium and radium. Vein deposits consist of uranium minerals filling in cavities such as cracks, veins, fractures, breccias, and stockworks associated with steeply dipping fault systems. There are three major subtypes of vein style uranium mineralisation: - intragranitic veins (Central Massif, France) - veins in metasedimentary rocks in exocontacts of granites - quartz-carbonate uranium veins (Erzgebirge Mts, Germany/Czech Republic; Bohemian Massif, Czech Republic) - uranium-polymetal veins (Erzgebirge Mts, Germany/Czech Republic; Saskatchewan, Canada) - mineralised fault and shear zones (central Africa; Bohemian Massif, Czech Republic) Intragranitic veins form in the late phase of magmatic activity when hot fluids derived from the magma precipitate uranium on cracks within the newly formed granite. Such mineralisation contributed much to the uranium production of France. Veins hosted by metasedimentary units in the exocontact of granites are the most important sources of uranium mineralisation in central Europe including the world class deposits Schneeberg-Schlema-Alberoda in Germany (96,000 t uranium content) as well as Pribram (50,000 t uranium content) and Jachymov (~10,000 t uranium content) in the Czech Republic. Also they are closely related to the granites, the mineralization is much younger with a time gap between granite formation and mineralisation of 20 million years. The initial uranium mineralisation consists of quartz, carbonate, fluorite and pitchblende. Remobilsation of uranium occurred at later stages producing polymetal veins containing silver, cobalt, nickel, arsenic and other elements. Large deposits of this type can contain more than 1,000 individual mineralized veins. However, only 5 to 12% of the vein areas carry mineralization and although massive lenses of pitchblende can occur, the overall ore grade is only about 0.1% uranium. The Bohemian Massif also contains shear zone hosted uranium deposits with the most important one being Rozna-Olsi in Moravia northwest of Brno. Rozna is currently the only operating uranium mine in central Europe with a total uranium content of 23,000 t and an average grade of 0.24%. The formation of this mineralisation occurred in several stages. After the Variscan Orogeny, extension took place and hydrothermal fluids overprinted fine grained materials in shear zones with a sulfide-chlorite alteration. Fluids from the overlying sediments entered the basement mobilising uranium and while uprising on the shear zone, the chlorite-pyrite material caused precipitation of uranium minerals in form of coffinite, pitchblende and U-Zr-silicates. This initial mineralisation event took place at about 277 million to 264 million years. During the Triassic a further mineralisation event took place relocating uranium into quartz-carbonate-uranium veins. Another example of this mineralisation style is the Shinkolobwe deposit in Congo, Africa, containing about 30,000 t of uranium. Intrusive associated depositsEdit Intrusive deposits make up a large proportion of the world's uranium resources. Included in this type are those associated with intrusive rocks including alaskite, granite, pegmatite and monzonites. Major world deposits include Rossing (Namibia), Ilimaussaq intrusive complex (Greenland) and Palabora (South Africa). Marine sedimentary phosphorite deposits can contain low grade concentrations of uranium, up to 0.01–0.015% U3O8, within fluorite or apatite. These deposits can have a significant tonnage. Very large phosphorite deposits occur in Florida and Idaho in the United States, Morocco, and some middle eastern countries. Collapse breccia pipe depositsEdit Collapse breccia pipe deposits occur within vertical, circular solution collapse structures, formed by the dissolution of limestone by groundwater. Pipes are typically filled with down-dropped coarse fragments of limestone and overlying sediments and can be from 30 to 200 metres (100 to 660 ft) wide and up to 1,000 metres (3,300 ft) deep. Primary ore minerals are uraninite and pitchblende, which occur as cavity fills and coatings on quartz grains within permeable sandstone breccias within the pipe. Resources within individual pipes can range up to 2500 tonnes U3O8 at an average grade of between 0.3 and 1.0% U3O8. The best known examples of this deposit type are in Arizona, USA, where several of these deposits have been mined. Mineralization occurs either as structurally controlled veins and breccias discordant to the stratigraphy and less commonly as stratabound mineralization either in extrusive rocks or permeable sedimentary facies. Mineralization may be primary, that is magmatic-related or as secondary mineralization due to leaching, remobilization and re-precipitation. The principal uranium mineral in volcanic deposits is pitchblende, which is usually associated with molybdenite and minor amounts of lead, tin and tungsten mineralization. Volcanic hosted uranium deposits occur in host rocks spanning the Precambrian to the Cenozoic but because of the shallow levels at which they form, preservation favors younger age deposits. Some of the more important deposits or districts are Streltsovskoye, Russia; Dornod, Mongolia; and McDermitt, Nevada. The average deposit size is rather small with grades of 0.02% to 0.2% U3O8. These deposits make up only a small proportion of the world's uranium resources. The only volcanic hosted deposits currently being exploited are those of the Streltsovkoye district of eastern Siberia. This is in fact not a single stand-alone deposit, but 18 individual deposits occurring within the Streltsovsk caldera complex. Nevertheless, the average size of these deposits is far greater than the average volcanic type. Surficial deposits (calcretes)Edit Surficial deposits are broadly defined as Tertiary to Recent near-surface uranium concentrations in sediments or soils. Mineralization in calcrete (calcium and magnesium carbonates) are the largest of the surficial deposits. They are interbedded with Tertiary sand and clay, which are usually cemented by calcium and magnesium carbonates. Surficial deposits also occur in peat bogs, karst caverns and soils. Surficial deposits account for approximately 4% of world uranium resources. The Yeelirrie deposit is by far the world's largest surficial deposit, averaging 0.15% U3O8. Langer Heinrich in Namibia is another significant surficial deposit. Metasomatite deposits consist of disseminated uranium minerals within structurally deformed rocks that have been affected by intense sodium metasomatism. Ore minerals are uraninite and brannerite. Th/U ratio in the ores is mostly less than 0.1. Metasomatites are typically small in size and generally contain less than 1000 t U3O8. Giant (up to 100 thousands t U) U deposits in sodium metasomatites (albitites) are known in Central Ukraine and Brazil. Two subtypes are defined based on host lithologies: - metasomatized granite; ex. Ross Adams deposit in Alaska, United States, Novokostantynivka deposit in Kirovogradska oblast, Ukraine. - metasomatised metasediment; ex. Zhovta Richka and Pervomayske deposits in Dnipropetrovska oblast, Ukraine and Valhalla deposit in northwestern Queensland, Australia. Metamorphic deposits those that occur in metasediments or metavolcanic rocks where there is no direct evidence for mineralization post-dating metamorphism. These deposits were formed during regional metamorphism of uranium bearing or mineralized sediments or volcanic precursors. Lignite deposits (soft brown coal) can contain significant uranium mineralization. Mineralization can also be found in clay and sandstone immediately adjacent to lignite deposits. Uranium has been adsorbed onto carbonaceous matter and as a result no discrete uranium minerals have formed. Deposits of this type are known from the Serres Basin, in Greece, and in North and South Dakota in the USA. The uranium content in these deposits is very low, on average less than 0.005% U3O8, and does not currently warrant commercial extraction. Black shale depositsEdit Black shale mineralisations are large low-grade resources of uranium. They form in submarine environments under oxygen-free conditions. Organic matter in clay-rich sediments will not be converted to CO2 by biological processes in this environment and it can reduce and immobilise uranium dissolved in seawater. Average uranium grades of black shales are 50 to 250 ppm. The largest explored resource is Ranstad in Sweden containing 254,000 t of uranium. However, there are estimates for black shales in the US and Brazil assuming a uranium content of over 1 million tonnes, but at grades below 100 ppm uranium. The Chattanooga Shale in the southeastern USA for example is estimated to contain 4 to 5 million tonnes at an average grade of 54 ppm. Because of their low grades, no black shale deposit ever produced significant amounts of uranium with one exception: the Ronneburg deposit in eastern Thuringia, Germany. The Ordovician and Silurian black shales at Ronneburg have a background uranium content of 40 to 60 ppm. However, hydrothermal and supergene processes caused remobilsation and enrichment of the uranium. The production between 1950 and 1990 was about 100,000 t of uranium at average grades of 700 to 1,000 ppm. Measured and inferred resources containing 87,000 t uranium at grades between 200 and 900 ppm are left. Other types of depositsEdit - There are also uranium deposits, of other types, in the Jurassic Todilto Limestone in the Grants District, New Mexico, USA. - The Freital/Dresden-Gittersee deposit in eastern Germany produced about 3.700 t of uranium from Permian hard coal and its host rocks. The average ore grade was 0.11%. The deposit formed in a combination of syngenetic and diagenetic processes. - In some countries like China trials are underway to extract uranium from fly ash. \|Wikimedia Commons has media related to Geology of Uranium.\| - "Cameco – Uranium 101". Retrieved February 1, 2009. - "Cameco – Uranium 101, Where is uranium found?". Retrieved 2009-01-28. - Plant, J., Simpson, P.R., Smith, B., and Windley, B.F. (1999), "Uranium Ore Deposits: Products of the Radioactive Earth", in Burns, P.C., and Finch, R. (eds.), Reviews in Mineralogy, Volume 38: Uranium: Mineralogy, Geochemistry and the Environment., Washington D.C., U.S.A.: Mineralogical Society of America, pp. 255–320, ISBN 0-939950-50-2CS1 maint: multiple names: authors list (link) CS1 maint: uses editors parameter (link) - "Uranium". Los Alamos National Laboratory. Retrieved 2009-02-11. - "WorldBook@NASA: Supernova". NASA. Archived from the original on 2006-09-30. Retrieved 2009-02-11. Cite uses deprecated parameter - Klein, Cornelis and Cornelius S. Hurlbut, Jr., Manual of Mineralogy, Wiley, 1985, 20th ed. pp. 307–308 ISBN 0-471-80580-7 - Merkel, B., und Sperling, B. (1998), Schriften 117: Hydrogeochemische Soffsysteme Teil II, DVWK, ISSN 0170-8147 Missing or empty \|title=(help)CS1 maint: multiple names: authors list (link) - "Mineralogy Database". Retrieved March 25, 2009. - Lally, J. & Bajwah, Z. (2006), Report 20: Uranium Deposits of the NT., Northern Territory Geological Survey, ISBN 0-7245-7107-8 Missing or empty - McKay, A.D. & Meiitis, Y. (2001), Australia's uranium resources, geology and development of deposits. (PDF), AGSO-Geoscience Australia, Mineral Resources Report 1, ISBN 0-642-46716-1, archived from the original (PDF) on October 2, 2012, retrieved February 12, 2009 Cite uses deprecated parameter - "Geology of Uranium Deposits - World Nuclear Association". world-nuclear.org. Retrieved 18 April 2018. - Douglas, G., Butt, C., and Gray, D. (2003). "Mulga Rock Uranium and Multielement Deposits, Officer Basin, WA" (PDF). Retrieved February 13, 2009.CS1 maint: multiple names: authors list (link) - "Page not found". www.allianceresources.com.au. Archived from the original on 13 March 2017. Retrieved 18 April 2018. Cite uses deprecated parameter - "AGM Presentation by MD Mr Patrick Mutz". allianceresources.com.au. Retrieved 18 April 2018. - "Archived copy". Archived from the original on 2009-12-25. Retrieved 2010-01-26. Cite uses deprecated parameter \|dead-url=(help)CS1 maint: archived copy as title (link) - Tilsley, J.E. (1988), "Genetic Considerations Relating to Some Uranium Ore Deposits", in Roberts, R.G., and Sheahan, P.A. (eds.), Ore Deposit Models, Volume 1, Ottawa, Canada: Geological Association of Canada, pp. 91–102, ISBN 0-919216-34-XCS1 maint: uses editors parameter (link) - "Marathon Resources Ltd – Paralana Mineral System (Mt Gee)". Archived from the original on 2009-04-10. Retrieved 2009-04-22. Cite uses deprecated parameter - Veselovsky, F., Ondrus, P., Gabsová, A., Hlousek, J., Vlasimsky, P., Chernyshew, I.V. (2003). "Who was who in Jáchymov mineralogy II". Journal of the Czech Geological Society (3-4 ed.). 48: 93–205.CS1 maint: multiple names: authors list (link) - Ruzicka, V. (1993). "Vein uranium deposits". Ore Geology Reviews. 8: 247–276. doi:10.1016/0169-1368(93)90019-U. - various... (1999), Chronik der Wismut, Chemnitz: Wismut GmbH - Kribek, B., Zák, K., Dobes, P., Leichmann, J., Pudilová, M., René, M., Scharm, B., Scharmova, M., Hájek, A., Holeczy, D., Hein, U.F., Lehmann, B. (2009). "The Rožná uranium deposit (Bohemian Massif, Czech Republic): shear zone-hosted, late Variscan and post-Variscan hydrothermal mineralization". Mineralium Deposita. 44: 99–128. Bibcode:2009MinDe..44...99K. doi:10.1007/s00126-008-0188-0.CS1 maint: multiple names: authors list (link) - unknown (2001), Analysis of uranium supply to 2050, Vienna: International Atomic Energy Agency - "Out of the Ashes". Cite journal requires - Dahlkamp, Franz (1993). Uranium Ore Deposits. Berlin, Germany: Springer-Verlag. ISBN 3-540-53264-1. - Burns, P.C., and Finch, R., eds. (1999), Reviews in Mineralogy, Volume 38: Uranium: Mineralogy, Geochemistry and the Environment., Washington D.C., U.S.A.: Mineralogical Society of America, ISBN 0-939950-50-2CS1 maint: uses editors parameter (link) - "Geoscience Australia Uranium factsheet" (PDF). Archived from the original (PDF) on 2007-09-11. Retrieved 2007-08-14. Cite uses deprecated parameter - "Uranium Ore Deposits". WISE Uranium Project. Retrieved 2008-09-20.
Two angles are considered complementary when the sum of their amplitudes is equal to 90º. In Euclidean geometry, the two acute angles that form a right triangle are complementary. The reason for this is that the internal sum of the angles of any triangle is 180 °, so if one of them is right, ie 90 °, the other two are complementary (they also measure 90 °). In the following drawing, we can see that `AhatBD + DhatBC` is always equal to 90º. Euclidean geometry, like all other mathematics, was born of the human need to understand what is around us. This geometry had its origin with the great mathematician Euclid, born about 330 BC in Syria. At the request of King Ptolemy I, he was invited to teach mathematics at the Alexandria Academy. With the passage of time gained prominence by the way he taught Geometry and Algebra. Although these disciplines were already known to mathematicians before Euclid, he was noted for having done a more in-depth study of the contents, and organized them logically, creating one of the greatest masterpieces of mathematics: "The Elements." This work consists of thirteen books that include arithmetic, geometry and algebra.
Vectors are magnitude and direction geometrical elements. A vector’s magnitude is represented by its length, which is shown as a line with an arrow pointing in the direction of the vector. As a result, vectors have both beginning and ending points and are represented by arrows. The notion of vectors evolved over a 200-year span. Physical quantities such as displacement, velocity, and acceleration are expressed using vectors. In addition, the late nineteenth-century breakthrough of electromagnetic induction ushered in the usage of vectors. The components of a vector dictate how it is divided. By dividing a vector with reference to each of the axes, we may compute its components. The many components of a vector can then be combined to generate the entire vector representation. In general, vectors are represented by an x-axis and y-axis in a two-dimensional coordinate plane, or by the x-axis, y-axis, and z-axis in a three-dimensional space. Vectors are mathematical representations that are directed and magnitude-based. The direction of a vector in a two-dimensional coordinate system is determined by the angle it makes with the positive x-axis. Here, vector V is split into two components: vx and vy. Vx is known as the Horizontal Component of the vector V. Vy is known as the vertical component of the vector V. Consider a vector A = Ax i + Ay j Now the horizontal component is: Ax And the vertical component is: Ay The initial vector, as specified by a collection of axes. The horizontal component of the vector extends from its origin to its furthest x-coordinate. The vertical component extends from the x-axis to the vector’s most vertical point. The two components, along with the vector, create a right triangle. Adding Vectors using components: To combine vectors, just represent them in terms of their horizontal and vertical components, then add them together. A vector of length 5 with a 36.9-degree angle to the horizontal axis, for example, will have a horizontal component of 4 units and a vertical component of 3 units. We would receive a vector twice as long at the same angle if we added this to another vector of the same magnitude and direction. By summing the horizontal components of the two vectors (4 + 4 ) and the two vertical components (3 + 3 ), this may be observed. These additions result in a new vector with an 8 (4 + 4 ) horizontal component and a 6 (3 + 3 ) vertical component. Simply position the tail of the vertical component at the head (arrow side) of the horizontal component and draw a line from the origin to the head of the vertical component to determine the resultant vector. The resulting vector is this new line. Because each of its components are twice as massive as they were previously, it should be twice as lengthy as the original. Subtraction of vectors using components: To remove vectors by components, subtract the two horizontal components from each other and repeat for the vertical components. Then, like in the last part, draw the vector that results. Problem: Find the x (horizontal) and y (vertical) components of a 12 magnitude vector that makes a 45 degree angle with the positive x-axis. Answer: V= 12 is the magnitude of the given vector, and it forms a 45 degrees angle. Vx = VCosθ = 12 is the x component of the vector. Cos45° = 12.(1/√2) = 6√2. Vy = VSinθ = 12 is the y component of the vector. Sin 45° = 12. (1/√2) = 6√2. As a result, both the x and y components of the vector are equal to 6√2. A vector is sometimes described as a collection of vector components that combine to form the vector. The projections of the vector on a set of mutually perpendicular reference axes are generally these components (basis vectors). The vector is said to be deconstructed or resolved with relation to that set. It is not unique since the axes on which the vector is projected dictate the breakdown or resolution of the vector into components.
About This Chapter Graphs of Algebraic Functions - Chapter Summary These video lessons show you how graphs work in algebra. Our instructors explain what a number line is and show the parts of a graph. Other lessons look at graphing basic functions, inverse functions and functions of functions. Polynomials functions are discussed here, as are exponentials, logarithms and the natural log. You will find out about horizontal and vertical asymptotes, as well as implicit functions. After completing all the lessons in this chapter, you should be prepared to: - Describe a number line - Name parts of a graph - Plot points on the coordinate plane - Graph a variety of functions - Explain the properties of polynomials functions - Understand exponentials and logarithms - Describe slopes and tangents on a graph - Show the equation of a line using point-slope formula Our lessons are brief and entertaining, and all include self-assessment quizzes that enable you to check what you've learned. The timeline's jump feature allows you to quickly find topics in each lesson that you need to study a bit more. The lessons are all led by instructors who are experts in the field. If you need extra help, it's easy to contact them with your questions. 1. What Is a Number Line? A number line is a visual representation of all real numbers. In this lesson, we'll learn how to identify points on a number line. We'll also practice addition and subtraction, letting the number line do all the hard work. 2. What Are the Different Parts of a Graph? Being able to read a graph isn't just vital for an algebra class. Graphs and charts are used everywhere! We'll take a crash course on the basic x/y plane used in algebra and the fundamental vocab you need. 3. Plotting Points on the Coordinate Plane If you'll be working with a graph, otherwise known as the coordinate plane, it's essential to understand how it works. This includes learning the parts of a graph, identifying points and plotting points. 4. Graphing Basic Functions Graphs are just like maps - when you know the language! Review how locations have x and y coordinates similar to latitude and longitude, and how to plot points in the Cartesian plane. 5. Compounding Functions and Graphing Functions of Functions We know that functions map numbers to other numbers, so what happens when you have a function of a function? Welcome to functions within functions, the realm of composite functions! 6. Understanding and Graphing the Inverse Function If you use a function to map a to b, is there a way to go back from b to a again? Learn how to find and graph inverse functions so that you can turn a into b and back into a. 7. Polynomial Functions: Properties and Factoring Everything from projectile motion to trigonometric functions can be described by polynomials. Review factoring, polynomials and quadratic functions in this lesson. 8. Polynomial Functions: Exponentials and Simplifying How do we keep track of a rapidly multiplying population of bunnies? Well, those are simply powers of 2. Review powers and simplify problems with exponents in this lesson. 9. Slopes and Tangents on a Graph Hit the slopes and learn how the steepness of a line is calculated. Calculate the slopes between points and draw the tangents of curves on graphs in this lesson. 10. Equation of a Line Using Point-Slope Formula It's time for a road trip to Las Vegas, and after four hours of driving at 60 mph ... Are we there yet? Learn the point-slope form of the equation of a line to help answer this age-old question. 11. Horizontal and Vertical Asymptotes No matter how hard you try to get to them, asymptotes remain out of reach. Learn about these invisible lines on graphs that show you places your equations just can't go. 12. Implicit Functions Sometimes inputting a variable into a function 'black box' doesn't yield a simple output. Find out what happens when you can't isolate the dependent variable on one side of the equal sign. Earning College Credit Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level. To learn more, visit our Earning Credit Page Transferring credit to the school of your choice Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you. Other chapters within the Accuplacer Math: Advanced Algebra and Functions Placement Test Study Guide course - Arithmetic with Rational Expressions - Factoring in Algebra - Expanding Polynomials - Manipulating Roots - Working with Exponents & Exponential Expressions - Solving & Graphing Linear Equations - Quadratic Equations - Calculating & Graphing Inequalities - Solving Systems of Linear Equations - Geometric Angles & Shapes - Line Theorems - Similarity & Congruency in Geometry - Pythagorean Theorem - Understanding Exponential & Logarithmic Functions - Trigonometric Functions & Equations - Accuplacer Math: Advanced Algebra and Functions Placement Test Flashcards
INTRODUCTION — Toll-like receptors (TLRs) are cell surface and intracellular molecules on eukaryotic cells that detect and respond to microbial antigens. They derive their name from homology to the Drosophila Toll molecule, an important component of dorsal-ventral patterning and antifungal defense [1,2]. TLRs are part of the innate immune system, which is a phylogenetically ancient system present in invertebrates and conserved through vertebrate evolution. Innate immune responses are initiated rapidly by exposure to microbes and precede the development of adaptive immune responses . Innate immunity is reviewed separately. (See "An overview of the innate immune system".) ROLE IN INNATE IMMUNITY — TLRs are a type of pattern recognition receptor (PRR), which are receptors specific for molecular components of micro-organisms that are not made by the host. The ligands for TLRs are called pathogen-associated molecular patterns (PAMPs), which are components of pathogenic microbes. In vertebrates, TLRs initiate protective functions that operate independently from adaptive immunity. They also play a critical role in adaptive immune responses by directing the differentiation of naïve T cells into effector T cells. Other examples of PRRs include nucleotide oligomerization domain (NOD)-like receptors (NLRs) and the retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs). (See "An overview of the innate immune system", section on 'Pattern recognition receptors'.) STRUCTURE AND FUNCTION OF TLRs — Different species have different numbers of distinct TLRs. At least 10 have been discovered in humans [1,2,4]. With the exception of TLR1, TLR2, and TLR6, TLRs initiate signaling by homodimerization (eg, two identical TLRs brought together). TLR2 forms heterodimers with TLR1 (TLR2/1) or TLR6 (TLR2/6). Receptor structure/organization, ligands, and signaling are summarized in the table (table 1) and figure (figure 1). The structure of all of the TLRs is similar. All have an extracellular ligand recognition and binding domain that contains leucine-rich repeats. All have a single transmembrane domain. The cytoplasmic (signaling) domain is homologous to the interleukin-1 (IL-1) receptor and is called a toll/IL-1 receptor or TIR domain. The final common pathway for TLR signaling involves the transcription factors, nuclear factor (NF) for the kappa (k) light chain enhancer in B cells (NF-kB) and activating protein-1 (AP-1). These transcription factors regulate a multitude of genes, including those encoding important proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), IL-1-beta, IL-6, IL-8, and IL-12. Some TLRs also activate production of type 1 (alpha and beta) interferons by inducing the interferon regulatory factors (IRFs) IRF3, IRF5, and IRF7. Cellular and tissue distribution — TLRs are differentially expressed on various leukocyte populations [2,5]. Monocytes and macrophages express all TLRs, except TLR3. Myeloid dendritic cells (MDCs) express TLR2/1, TLR3, TLR4, TLR5, and TLR8, while plasmacytoid dendritic cells (PDCs) express TLR7 and TLR9. TLR2/6, TLR4, and TLR8 are found on mast cells. B cells express TLR3, TLR7, TLR9, and TLR10, while T cells express TLR3 and TLR9. A variety of tissue types may express one or more TLRs. As an example, the basolateral surfaces of intestinal epithelial cells express TLR5, whereas fibroblasts and keratinocytes express TLR3 on the cell surface . The cellular localization of TLRs varies. TLR2/1, TLR2/6, TLR4, TLR5, TLR10, and TLR11 are localized to cell surfaces, whereas TLR3, TLR7, TLR8, and TLR9 are localized within endosomes. The cell surface expression of TLRs, such as TLR4, which recognizes lipopolysaccharide (LPS), is hypothesized to allow recognition of extracellular molecules released from pathogens. Endosomal expression of TLR3, TLR7, TLR8, and TLR9 allows recognition of microbial nucleic acids following their uptake and degradation in phagolysosomes. TLR3, TLR7, TLR8, and TLR9 interact with an endoplasmic reticulum (ER) membrane protein called UNC93B (UNC93 homolog B), which is essential for proper signaling . Additionally, endosomal expression of TLR3, TLR7, TLR8, and TLR9 may prevent activation by host nucleic acids and the development of autoimmunity. Signaling — All TLRs, except TLR3, utilize the cytoplasmic proximal signaling intermediate myeloid differentiation primary response protein 88 (MyD88), either by itself (TLR5, TLR7, TLR8, and TLR9) or together with the adapter molecule toll/interleukin-1 (IL-1) receptor (TIR) domain-containing adapter protein (TIRAP/MyD88 adapter-like [MAL], TLR2/1, TLR2/6, and TLR4) (figure 1) [1,2,8]. There is also a MyD88-independent pathway via the molecule TIR domain-containing adapter-inducing interferon-beta (IFN-beta) (TRIF), which is used by TLR3 and TLR4 (TLR4 also utilizes the intermediate TRIF-related adapter molecule [TRAM]). The MyD88 adapter connects through interleukin-1 (IL-1) receptor-associated kinases 1 and 4 (IRAK1, IRAK4), tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), and transforming growth factor (TGF)-beta-activated protein kinase 1 (TAK1) to the mitogen-activated protein kinases (MAPKs). This complex kinase cascade culminates in activation of the family of heterodimeric transcription factors known as activating protein-1 (AP-1). These transcription factors regulate a broad array of genes influencing cell survival, activation, and proliferation. The TAK1 adapter also leads to activation of the inhibitor of NF-kB kinase (IKK) and resultant activation of NF-kB. This is another family of heterodimeric transcription factors regulating many genes with important roles in immune responses, as well as in the physiology of a broad array of other cell types. These include cytokines, chemokines and growth factors, lymphocyte receptors, adhesion molecules, acute-phase reactants, and other transcription factors. Ligation of TLR3 leads to activation of TRAF3 followed by tank-binding kinase 1 (TBK1) and IKK, which in turn activate interferon regulatory factor 3 (IRF3), leading to production of type 1 interferons. TLR7, TLR8, and TLR9 signal via a MyD88-dependent pathway that utilizes IRAK1/4, IKK-alpha, TRAF3/6, and intracellular osteopontin (iOPN), which activates IRF7, leading to production of interferon-alpha (IFN-alpha) . In addition, TLR7-induced production of IFN-alpha has been shown to be dependent upon activation of IRF5 . Regulation — Both the cell surface expression of TLRs and the intracellular consequences of TLR ligation are regulated by a variety of factors. These include exposure to microbial products, other TLR ligands, and cytokines. Suppressor of cytokine signaling (SOCS) proteins and ubiquitin-mediated degradation of signaling proteins are involved in negative regulation of TLR signaling [11,12]. Within the gastrointestinal tract, the factors that maintain tolerance to commensal host flora while detecting/containing pathogenic bacteria with appropriate inflammatory responses are incompletely understood. The detection of common PAMPs in pathogenic and nonpathogenic bacteria would be anticipated to activate the same inflammatory response. Nevertheless, the detection of commensal bacteria within the intestines can induce tolerance. TLR signaling can contribute to intestinal homeostasis by regulating intestinal epithelial cell proliferation and epithelial integrity . Expression and localization of TLRs in the intestinal epithelium may directly relate to their role in maintaining homeostasis versus inducing inflammation. For example, within the intestinal epithelium, TLR9 activation through the apical membrane induces tolerance, whereas TLR9 activation via the basolateral membrane induces an inflammatory response through the canonical NF-kB pathway. Differential spatial expression of pattern recognition receptors (PRRs) in epithelia may constitute a critical mechanism of distinguishing nonpathologic from pathologic bacteria. Regulation of TLR function is highly complex and still incompletely understood and beyond the scope of this review [14-17]. SPECIFIC TLRs — The ligands, cellular expression, signaling molecules utilized, and resultant cellular effects of ligation for each of the TLRs are summarized in the table (table 1). Additional information is presented below. ●TLR2/1 – The heterodimer of TLR2 with TLR1 binds to cell wall components of bacteria and mycobacteria. TLR2/1 binds triacyl lipopeptides/lipoproteins and some diacyl lipopeptides [18-20]. It also interacts with porins of Neisseria . TLR2/1 is expressed on myeloid dendritic cells (MDCs) and signals via the canonical myeloid differentiation primary response protein 88 (MyD88) pathway with the toll/interleukin-1 (IL-1) receptor (TIR) domain-containing adapter protein (TIRAP). TLR2/1 also exists in a soluble form that can inhibit signaling via the membrane-bound receptor . ●TLR2/6 – The heterodimer of TLR2 with TLR6 displays a preference for recognizing diacyl lipopeptides, although it can recognize some triacyl lipopeptides [18-20]. TLR2/6 is expressed on mast cells, and it also signals via the canonical MyD88 pathway with the TIRAP. ●TLR3 – TLR3 binds double-stranded RNA (dsRNA), which is produced in the replication of many viruses . TLR3 may also bind to synthetic dsRNA, such as polyinosinic-polycytidylic acid (polyI:C) . TLR3 is found within endolysosomes (membrane-bound intracellular compartments formed by the fusion of vesicles of internalized viral debris and lysosomes containing degradative enzymes) of MDCs, B cells, T cells, and natural killer (NK) cells . TLR3 signals via a MyD88-independent pathway (TIR domain-containing adaptor-inducing interferon [TRIF]) and induces production of type 1 interferon-beta (IFN-beta) in addition to inflammatory cytokines. ●TLR4 – The principal ligand for TLR4 is the lipopolysaccharide (LPS) of Gram-negative bacteria . The interaction of LPS with TLR4 occurs in a complex with LPS-binding protein (LBP), CD14, and a molecule called myeloid differentiation factor-2 (MD-2) (figure 1). Additional ligands include the fusion protein of respiratory syncytial virus (RSV), heat shock proteins of organisms, such as Chlamydia pneumoniae, and components of the extracellular matrix, such as fibronectin, hyaluronic acid, and heparan sulfate [27-29]. TLR4 is expressed on MDCs and mast cells and can signal via MyD88 with TIRAP. It may also induce type 1 IFN through the MyD88-independent pathway via TRIF-related adaptor molecule (TRAM). ●TLR5 – TLR5 recognizes bacterial flagellin . It is expressed on MDCs and transduces signals via MyD88. ●TLR7 and TLR8 – TLR7 and TLR8 are very similar in their ligand binding and signaling [31-33]. Both bind to single-stranded RNA (ssRNA) from viruses, such as influenza and human immunodeficiency virus-I (HIV-I). They also recognize imidazoquinolines (synthetic heterocyclic organic molecules), such as imiquimod, and guanosine analogs, such as loxoribine. TLR7 is expressed on MDCs, plasmacytoid dendritic cells (PDCs), and B lymphocytes. TLR8 is expressed on MDCs and mast cells. Both signal directly via MyD88. ●TLR9 – TLR9 interacts with unmethylated cytosine guanine dinucleotide (CpG) motifs in microbial DNA . TLR9 is expressed within endolysosomes of PDCs, B cells, and T cells and signals directly via MyD88. Activation of PDCs (also known as IFN-producing cells) through TLR7 and TLR9 leads to production of large quantities of IFN-alpha, which plays a critical role in antiviral innate immunity. Additionally, PDCs, by virtue of their production of IFN-alpha and IL-12, are potent inducers of differentiation of naïve T cells into T helper type 1 (Th1) effector T cells. ●TLR10 – TLR10 is a modulatory PRR with largely inhibitory functions [35,36]. TLR10 is believed to exert inhibitory functions through competition with ligand binding to TLRs. Furthermore, TLR10 may compete for heterodimer formation with TLR2. TLR10 activation also leads to increased expression of IL-1 receptor antagonist (IL-1RA), which decreases inflammation. Recently, TLR10 was found to be a receptor for HIV gp41 binding, leading to activation of NF-kB and IL-8 production in macrophages, monocytes, and mammary epithelial cells, suggesting it may be an innate sensor of HIV infection. Binding of HIV gp41 to TLR10 leads to upregulation of expression of TLR10. However, increased expression of TLR10 may result in enhanced HIV infection by allowing entry into monocytes, macrophages, and epithelial cells . CELLULAR RESPONSES INDUCED BY TLRs — The response to various combinations of TLRs depends on the cell expressing that TLR, the relative amounts and types of TLRs present, as well as other stimuli and the developmental program of the target cell. ●TLR ligation of mononuclear cells may potentiate the microbicidal activity of phagocytic cells. As an example, TLR2/1 or TLR2/6 ligation by cell wall components of Mycobacterium tuberculosis induces nitric oxide production in mice and other bactericidal mechanisms in humans . The same ligand/receptor combination may also lead to apoptosis in macrophages . This mechanism could potentially limit the spread of microbes that are replicating intracellularly. ●TLR activation of epithelial cells can induce production of antimicrobial peptides (defensins) that provide protection against a wide variety of pathogens. TLR activation in intestinal epithelial cells can contribute to intestinal homeostasis by regulating intestinal cell proliferation and epithelial integrity. Depending on the cellular localization of TLRs in intestinal epithelia (ie, apical membrane), TLR activation may induce tolerance, whereas activation of TLRs within the basolateral membrane induces an inflammatory response to invasive bacteria [40-42]. ●Activation of TLRs on dendritic cells leads to antigen presentation, production of IL-12, and upregulation of costimulatory molecules (CD80, CD86), which directs the differentiation of naïve T cells into antigen-specific Th1 effector T cells . (See "The adaptive cellular immune response: T cells and cytokines".) ●TLR activation (TLR3, TLR7, TLR8, TLR9) results in production of type 1 interferons, which plays a crucial role in antiviral innate immunity. Different TLR ligands may lead to somewhat different cytokine responses or may induce type 1 interferon and lead to activation of qualitatively different types of immune responses (eg, T helper type 1 [Th1] versus T helper type 2 [Th2] T cell differentiation) . The response to various combinations of TLRs also depends on the relative amounts and types of TLRs on the cell surface, as well as other stimuli and the developmental program of the target cell. Because pathogens coevolved with their hosts, we (the host) have acquired sophisticated mechanisms for resisting infection, including TLRs. In turn, pathogens have developed strategies to circumvent many of these mechanisms. For example, vaccinia virus encodes molecules with homology to toll/interleukin-1 (IL-1) receptor (TIR) domains and can inhibit signaling via TLR3 and TLR4 [44,45]. TLR SIGNALING DEFECTS IN PRIMARY IMMUNODEFICIENCY — Defects have been identified in molecules that transduce signals from TLRs and lead to primary immunodeficiency (table 2). Specific disorders — The degree of immunologic impairment is related to where in the TLR signaling pathway the defect occurs (figure 2). Defects that occur proximally in the TLR pathway, such as deficiency in myeloid differentiation primary response protein 88 (MyD88) or interleukin-1 (IL-1) receptor-associated kinase 4 (IRAK4) lead to susceptibility to a limited number of pathogens (typically pyogenic bacteria), since these defects only impair the function of TLRs and IL-1R. In contrast, distal defects involving transcription factors (ie, nuclear factor [NF]-kB complex) lead to broader infectious susceptibilities (eg, bacteria, viruses, fungi, and opportunistic organisms), as well as developmental abnormalities (ie, ectodermal dysplasia). This is because of the diverse immune and developmental mechanisms that signal through NF-kB, including pathways in innate immunity (ie, TLRs), adaptive immunity (ie, T cell receptor, B cell receptor, and CD40), and ectodermal development (ie, ectodysplasin A receptor). MyD88/IRAK4/IRAK1 deficiency — All TLRs, except TLR3, use the cytoplasmic proximal signaling intermediate myeloid differentiation primary response protein 88 (MyD88), either by itself or together with the adapter molecule toll/IL-1 receptor domain-containing adapter protein (TIRAP). MyD88 deficiency was initially described in nine children suffering from recurrent and severe pyogenic bacterial infections . These children were susceptible to invasive infections with Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa, but had normal resistance to other common bacteria, viruses, fungi, and parasites. Three children died before the age of 1 year, while another six were alive at ages 3 to 16 years at the time of publication. Susceptibility to infection improved with age in affected patients, although MyD88 levels did not change, suggesting that maturation of the adaptive immune system may compensate for defective TLR function. The defect displayed autosomal recessive inheritance. MyD88 deficiency is clinically indistinguishable from IL-1 receptor-associated kinase 4 (IRAK4) deficiency, since IRAK4 associates with MyD88 in signal transduction . Deficiency of IRAK4 (MIM 607676) impairs signaling from the TLRs that associate only with the MyD88 adapter (figure 3). These include TLR2/1, TLR2/6, TLR5, TLR7, TLR8, and TLR9. TLR4 signals through MyD88, but can also make use of the toll/IL-1 receptor (TIR) domain-containing adapter-inducing interferon-beta (IFN-beta) (TRIF)-related adapter molecule (TRAM)/TRIF pathway. TLR3 is unaffected. Signaling by the IL-1 receptor and T cell receptor activation are also impaired . Peripheral blood mononuclear cells from patients with IRAK4 deficiency or MyD88 deficiency do not produce proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha), IL-1, and IL-6 when stimulated via IL-1 or IL-18 receptors or TLRs. The lack of responsiveness to IL-1 results in impaired fever responses to bacterial infection. The lack of significant fever and the unexpectedly low level of C-reactive protein (CRP) in the setting of a serious bacterial infection can be a clue to the possibility of IRAK4 deficiency or MyD88 deficiency. The clinical and laboratory features of IRAK4 deficiency are indistinguishable from MyD88 deficiency, since IRAK4 associates with MyD88 in signal transduction (figure 3). Patients with IRAK4 deficiency have recurrent severe infections (cellulitis, arthritis, meningitis, osteomyelitis, organ abscesses, and sepsis), mainly caused by S. aureus, S. pneumoniae, and P. aeruginosa [47,49,50]. One series described 48 patients who experienced recurrent bacterial infections, mostly of the upper respiratory tract and skin . None had severe viral, fungal, or parasitic infections. Initial invasive infections occurred before the age of two years in 88 percent. Invasive pneumococcal infections caused the most morbidity and mortality and were the cause of death in 33 percent. In patients with either IRAK4 deficiency or MyD88 defects, susceptibility to infections seems to improve with age, regardless of therapy [47,52]. In the largest series, no infectious deaths were reported in patients over the age of 8 years and no invasive infections after the age of 14 years . Serum immunoglobulins are normal, specific antibody levels against polysaccharide antigens may be low or normal, and B cell subsets and function in vitro are normal. T cell responses to mitogens and recall antigens are also normal. Peripheral eosinophilia and elevated serum immunoglobulin E (IgE) may be observed. The diagnosis can be made by measuring cytokine production by leukocytes that have been activated by various TLR ligands (TLR function assay, available in at least one commercial laboratory) . Absence of functional MyD88 or IRAK4 results in an absence of proinflammatory production in affected patients. The absence of TLR-induced cytokine production in these patients must be then followed by gene sequencing to identify the precise genetic defect. Targeted gene panels are now commercially available and are cost effective. Meticulous skin care to minimize bacterial colonization of the skin is also an essential element of patient management, since these patients remain susceptible to skin infections. Antibiotic or other therapy is dictated by specific pathogen sensitivity and the focus of infection. Antibiotic prophylaxis and/or immune globulin replacement therapy may be considered. Most MyD88- or IRAK4-deficient patients are maintained on antibiotic prophylaxis with amoxicillin or sulfamethoxazole-trimethoprim indefinitely. For the roughly 50 percent of MyD88- or IRAK4-deficient patients that do not have adequate antibody responses to polysaccharide pneumococcal vaccine (ie, Pneumovax), immune globulin replacement therapy is helpful, at least until adolescence when invasive infection risks diminish . (See "Immune globulin therapy in primary immunodeficiency".) IRAK1 deficiency in a male due to a 112kb deletion, which deleted both MECP2 and IRAK1 on the X chromosome, has been reported . Unfortunately, no information on the infectious consequences of the loss of IRAK1 is available because the patient died of progressive neurologic and respiratory insufficiency, presumably from absence of MECP2. Analysis of transformed fibroblasts from this patient demonstrated absent responses to stimulation of TLR ligands, whereas signaling downstream of IL-1R was relatively unimpaired, suggesting that IRAK1 plays an essential role in signaling downstream of TLRs but a redundant role downstream of IL-1R in fibroblasts. In contrast, TLR signaling in the patient's peripheral blood mononuclear cells was unimpaired, indicating that IRAK1 plays a redundant role that may be compensated by IRAK2. UNC93B1 deficiency, TLR3 mutations, TRIF deficiency, TRAF3 deficiency, and TBK1 deficiency — UNC93B1 (UNC93 homolog B1) is an endoplasmic reticulum (ER) protein that is involved in the transport of the nucleotide-sensing TLR7 and TLR9 from the ER to endolysosomes. Signaling through TLR3, TLR7, TLR8, and TLR9 normally induces production of type 1 interferons following binding to viral RNA (figure 3). Type 1 interferons are critical to controlling certain viruses during the earliest stages of infections. HSV-1 encephalitis — Deficiency of UNC93B1 or TLR3 (MIM 610551 and MIM 613002) leads to susceptibility to herpes simplex virus type 1 (HSV-1) encephalitis due to decreased production of interferons in the central nervous system [55-58]. Both autosomal dominant and autosomal recessive forms of toll/interleukin-1 (IL-1) receptor domain-containing adaptor-inducing interferon (TRIF) deficiency have been shown to cause susceptibility to HSV-1 encephalitis . Autosomal dominant deficiency of tumor necrosis factor (TNF) receptor-associated factor 3 (TRAF3), which leads to reduced but not absent TRAF3 function, is another cause of susceptibility to HSV-1 encephalitis . Finally, heterozygous mutations in tank-binding kinase 1 (TBK1) also result in susceptibility to HSV-1 encephalitis . This group of patients with defective TLR3 signaling demonstrates the essential role of TLR3 in the central nervous system in the prevention of HSV-1 encephalitis. (See "Herpes simplex virus type 1 encephalitis", section on 'Host susceptibility'.) Severe influenza — Deficiencies in TLR3, interferon regulatory factor 7 (IRF7), and IRF9 have been identified in children with life-threatening influenza pneumonia [62-64]. Additionally, a heterozygous missense mutation in TLR3 (F303S) was associated with influenza-associated encephalopathy, likely due to haploinsufficiency of TLR3 function . Severe COVID-19 — Type 1 interferon production plays an essential role in host defense against coronaviruses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is an RNA virus that is likely detected intracellularly by TLR3, 7, and 8, as well as RIG-I and MDA5. SARS-CoV-2 encodes numerous genes that can inhibit type 1 interferon production by blocking innate sensing (nsp16, 14), interferon production (M protein, N protein, nsp3, ORF 3b,4a, 4b, 5, 6), and interferon signaling (nsp1, ORF4b, 6), which contributes greatly to its virulence. Defects in genes involved type 1 interferon production, including TLR3, IRF7, UNC93B1, TICAM1, TBK1, and interferon alpha and beta receptor subunit 1 (IFNAR1) were found in 3.5 percent of patients hospitalized with life-threatening COVID-19 (figure 3) . Ten of 23 patient for whom blood samples were available from early in their hospitalization showed very low IFN-alpha levels compared with other patients with milder COVID-19 disease. In a parallel study by the same group, the presence of autoantibodies against specific type 1 interferons, which resulted in undetectable serum levels, were found in 10.2 percent of patients with life-threatening COVID-19 pneumonia compared with 0.33 percent of healthy individuals . Thus, defects in the pathways generating type 1 interferons, inhibition of type 1 interferon production, and autoantibodies that neutralize interferons predispose to severe COVID-19. NEMO defects — NF-kB essential modifier (NEMO), also called the inhibitor of NF-kB kinase (IKK)-gamma, is encoded by a gene on the X chromosome (IKBKG). NEMO is required for the proper function of IKK, which inactivates the inhibitor of NF-kB (I-kappa [k]-B) proteins (figure 3). In the absence of IKK activity, I-kB remains bound to NF-kB, holding it in the cytoplasm in an inactive form and preventing its translocation to the nucleus to exert its transcriptional regulatory activities. Thus, in the absence of NEMO function, NF-kB signaling is blocked, shutting down many pathways, including innate immune functions (ie, TLRs, nucleotide-binding oligomerization domain [NOD]-like receptors [NLRs], retinoic acid-inducible gene-I [RIG-I]-like receptors [RLRs]), adaptive immune functions (T cell receptor, B cell receptor, CD40), and developmental pathways (ie, ectodysplasin A receptor in ectoderm and receptor activator of NF-kB [RANK] in osteoclasts) (figure 2). Complete absence of NEMO function is lethal in male embryos, and partial deficiency in females leads to a condition called incontinentia pigmenti . (See "Incontinentia pigmenti".) Mutations that permit partial function of NEMO (ie, hypomorphic mutations) cause immunodeficiency of varying severity in males, ranging from recurrent sinopulmonary infections to extreme susceptibility to all classes of pathogens, including mycobacteria and opportunistic organisms. Because NF-kB also transduces signals from receptor systems important for the development of skin and skin appendages, the majority of patients with hypomorphic mutations also have ectodermal dysplasia, a disorder known as ectodermal dysplasia with immunodeficiency (ED-ID) (figure 2), although it can be present in very subtle ways in some patients. Ectodermal dysplasia is characterized by conical or absent teeth; fine, sparse hair; and hypohidrosis due to decreased sweat glands. NEMO mutations are discussed separately. (See "Mendelian susceptibility to mycobacterial diseases: Specific defects", section on 'NEMO deficiency'.) I-kappa-B defects — Multiple patients have been found to have mutations in the alpha subunit of the I-kB complex, an autosomal dominant form of ED-ID (figure 3). The phenotype is very similar to NEMO deficiency, leading to variable susceptibilities to infectious agents with (or without) ectodermal dysplasia. Testing of TLR function in patients suspected of having impaired NF-kB function can be informative. The degree of impairment in TLR function can range from insignificant to severely impaired, depending on the mutation in IKBKG or NFKBIA . (See "Combined immunodeficiencies: An overview".) DOCK8 deficiency — Dedicator of cytokinesis 8 (DOCK8) deficiency is a combined immunodeficiency characterized by markedly elevated levels of immunoglobulin E (IgE), hypereosinophilia, atopic disorders, recurrent sinopulmonary infections, cutaneous candidiasis, and viral infections of the skin . These patients have T cell lymphopenia and impaired serologic memory. DOCK8 is a guanine nucleotide exchange factor and an adapter protein important in TLR9 signaling and T cell receptor-driven Wiskott-Aldrich syndrome protein (WASp) activation and cytoskeleton reorganization . DOCK8 deficiency results in impaired TLR9-induced B cell proliferation and immunoglobulin production, leading to poorly sustained protective antibody responses (figure 4). Patients also have a significant reduction in the number of circulating plasmacytoid dendritic cells (PDCs). The PDCs of DOCK8-deficient patients appear to produce less IFN-alpha in response to TLR9 activation, perhaps contributing to their susceptibility to viral infections [71,72]. (See "Combined immunodeficiencies: Specific defects", section on 'DOCK8 deficiency'.) HOIL-1/HOIP deficiency — Heme-oxidized IRP2 ubiquitin ligase-1 (HOIL-1) is a component of the linear ubiquitination chain assembly complex (LUBAC) that is essential for stabilization of the LUBAC and NF-kB activation downstream of the IL-1 receptor. HOIL-1 deficiency is an autosomal recessive disorder that causes impaired IL-1 activation of NF-kB in patient fibroblasts. Conversely, monocytes from these patients are hyper-responsive to IL-1 (figure 5). This condition results in a unique association of immunodeficiency, autoinflammation, periodic fever, and muscular amylopectinosis. Homozygous mutations in HOIL-1 interacting protein (HOIP), the gene encoding the catalytic component of LUBAC, leads to similar cellular impairments and a clinical condition nearly identical to HOIL-1 deficiency [73,74]. (See "Autoinflammatory diseases mediated by NFkB and/or aberrant TNF activity", section on 'LUBAC deficiency'.) Common variable immunodeficiency — Defects in the functioning of TLR7 and TLR9, normally prominent on B cells and dendritic cells, have been identified in patients with common variable immunodeficiency. These findings may be important in ultimately understanding the impaired B cell maturation that characterizes this disorder. TLR9-induced activation of STAT3 in B cells plays an important role in B cell maturation into memory B cells. A recent report that examined seven patients with CVID demonstrated reduced TLR9-induced activation of STAT3, which may underlie impaired antibody responses in some CVID patients [75-77]. (See "Pathogenesis of common variable immunodeficiency".) Heterozygous mutations in NF-kB1 (also known as p105/p50), leading to haploinsufficiency of NF-kB1 function and impaired activation of the canonical NF-kB pathway, have been shown to cause common variable immunodeficiency and hypogammaglobulinemia [78,79]. These patients suffered from recurrent sinopulmonary infections, chronic obstructive pulmonary disease (COPD), bronchiectasis, lymphadenopathy, skin infections, autoimmune cytopenias, inflammatory bowel disease, carcinomas, and adenocarcinomas. In addition, heterozygous mutations in NF-kB2 (also known as p100/p52), causing haploinsufficiency of NF-kB2 function and impaired activation of the noncanonical NF-kB pathway, lead to hypogammaglobulinemia, recurrent infections, autoimmunity, and adrenal insufficiency. Defective activation of TLRs has not been described in NF-kB1 or NF-kB2 haploinsufficiency (figure 2). When to suspect — Immunodeficiencies resulting from defects with TLR pathways are extremely rare. The clinical scenarios in which a TLR pathway defect should be considered include the following: ●An infant or child who develops invasive pyogenic infections (meningitis, adenitis, abscesses) caused by S. pneumoniae, S. aureus, or P. aeruginosa, particularly if there is minimal or no fever or an unexpectedly small rise in CRP. IRAK4 or MyD88 deficiency should be considered in this situation, after more common forms of immunodeficiency have been excluded (figure 2). (See 'MyD88/IRAK4/IRAK1 deficiency' above.) ●The patient with HSV-1 encephalitis could have a defect within the TLR3 pathway, although assessment of TLR function is not helpful, because TLR function is usually normal in blood cells and evaluation of fibroblasts is required. Instead, gene sequencing through targeted gene panels or whole exome sequencing may be the most efficient approach. (See 'UNC93B1 deficiency, TLR3 mutations, TRIF deficiency, TRAF3 deficiency, and TBK1 deficiency' above.) ●The patient with ectodermal dysplasia and recurrent infections (bacterial, viral, or mycobacterial) most likely has a mutation within NEMO or I-kB-alpha, as this combination of findings is relatively specific for these immunodeficiencies. However, not all patients with mutations in these proteins have ectodermal dysplasia. TLR-induced proinflammatory cytokine production has been shown to be variably reduced in many but not all affected individuals. Genetic detection of NEMO mutations can be confounded by the presence of a pseudogene. Genetic analysis can be obtained through commercial laboratories . (See 'NEMO defects' above and 'I-kappa-B defects' above.) Initial evaluation — The initial evaluation of all patients suffering from recurrent infections begins with a detailed history of past infections, including frequency and severity, the specific sites of infections, and review of any available culture data to identify causative organisms. Because many immunodeficiencies are recessive traits, the clinician must ask about consanguinity within the family, although a lack of consanguinity does not rule out the possibility of compound heterozygous mutations. A family history of recurrent infection only affecting males focuses the evaluation on X-linked disorders. Physical exam findings can provide important clues to possible immune disorders (eg, lack of tonsils in X-linked agammaglobulinemia or ectodermal dysplasia in NEMO/I-kB-alpha defects). Laboratory evaluation should start with a complete blood count and differential to assess numbers of neutrophils and lymphocytes. Immunoglobulin levels should be measured, along with an assessment of specific antibody production (tetanus and pneumococcal titers). Immunophenotyping of lymphocytes, including assessment of memory T lymphocyte and memory B lymphocyte populations should be performed, along with T lymphocyte proliferation in response to mitogens and antigens. Immunologic testing is reviewed in more detail separately. (See "Laboratory evaluation of the immune system".) If these evaluations fail to identify a potential immunodeficiency, further specialized testing is indicated. Referral and testing for TLR function — Additional testing is best performed by an experienced immunologist who is familiar with this rare group of immunodeficiencies. Testing of TLR function is available through commercial reference laboratories [81,82]. A variety of in vitro methods may be applied. Most measure inflammatory cytokine production (eg, IL-6, IL-1, or tumor necrosis factor [TNF]) after stimulation with one or more TLR ligands (eg, bacterial lipopolysaccharide [LPS], an agonist of TLR4) . Tests of TLR function are very sensitive to the condition of the cells. Blood should be sent as soon as possible after collection, especially if it is to be shipped a long distance (ship at ambient temperature, protect from heat or cold). If possible, the patient should be clinically well for at least a few weeks prior to testing and not actively recovering from any serious illness. A shipping control from an unrelated healthy donor should accompany the specimen. Abnormal tests need to be confirmed by repeat testing. Persistently abnormal tests should be followed up by specific genetic tests. Significance of TLR polymorphisms — A rapidly expanding area of research is the epidemiologic study of the many single nucleotide polymorphisms (SNPs) that have been identified in various TLR genes. Some early reports stated that certain variants of TLR2 and TLR4 were associated with impaired signaling after binding their natural ligands [84,85]. SNPs in TLR1 have been associated with candidemia, and SNPS in TLR4 have been associated with invasive aspergillosis among recipients of hematopoietic cell transplants [86,87]. (See "Epidemiology and clinical manifestations of invasive aspergillosis", section on 'Risk factors'.) However, subsequent reports have challenged these findings and have stated that some of these polymorphisms do not have functional consequences [83,88,89]. It is not clear which is correct. Perhaps the answer depends on the specific stimulus, the response that is measured, or other variables. ASSOCIATIONS BETWEEN TLRs AND OTHER DISEASES Atherosclerosis — A large body of evidence has accumulated that various infectious agents have epidemiologic links with atherosclerotic heart disease . These include Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus type 1 (HSV-1), and hepatitis B and C . Chronic infection and serum lipopolysaccharide (LPS) level have been identified as risk factors in a prospective study of the development of atherosclerotic heart disease . Human atherosclerotic plaques contain endothelial cells and macrophages expressing TLR1/2 and TLR4 . Minimally modified low density lipoprotein is an agonist of TLR4 . It binds independently of CD14 and myeloid differentiation factor-2 (MD-2) and can induce production of chemokines, such as interleukin-8 (IL-8). Animal data strongly suggest roles for TLRs (particularly TLR4) in recognizing foreign (microbial) and self (extracellular matrix, heat shock proteins) molecules, activating endothelial cells, and recruiting and activating monocytes and macrophages to form inflammatory foci that could lead to the formation of atheromatous plaques . Allergy and asthma — Most studies have found that exposure to bacterial products has been associated with protection from the development of allergic disease, and TLRs may be integral to the mechanisms involved. However, subsequent work suggests that this relationship may not be so straightforward. ●An association between exposure to endotoxin, which forms complexes with TLR4, and protection from allergic sensitization was found in multiple studies. As an example, a report of 61 wheezing infants recorded significantly lower levels of endotoxin in the house dust of those with the highest degree of immunoglobulin E (IgE) sensitization to environmental allergens . Another study showed that lipoteichoic acid, another component of bacterial cell walls, interacts with TLR2 to downregulate the receptor of IgE (Fc-epsilon-RI) on mast cells . ●In contrast, a different model showed that activation of TLR4 on the surface of pulmonary epithelial cells seemed to promote the development of allergic airway responses and asthma . In a mouse model, naturally occurring combinations of dust mite allergens and LPS were found to trigger epithelial cells through TLR4, leading to eosinophil recruitment and the production of the T helper type 2 (Th2) cytokines, interleukin-5 (IL-5) and interleukin-13 (IL-13) . Simultaneous inhalation of a TLR4 antagonist completely eliminated the effect. However, the dose of the TLR agonist also plays a role. In another study, low doses of endotoxin acting on TLR4 were observed to enhance Th2 inflammation in a mouse asthma model, whereas high doses induced a T helper type 1 (Th1) response . ●The importance of early exposure to a rich, diverse microbiota in the prevention of atopy is an active area of research. Microbial components (endotoxin) provide robust activation of TLRs, which shape immune responses . Loss of microbiota diversity, on the other hand, may predispose to the development of atopy and asthma. Microbiome diversity can be influenced by infections and the use of antibiotics [100,101]. Mouse models suggest that TLR activation of CD103+ dendritic cells in the gut may play an important role in inducing development of T regulatory cells, leading to induction of tolerance . Furthermore, increased expression of TLR2 and TLR4 on T regulatory cells may be associated with augmented suppressive functions . ●A meta-analysis of TLR2, TLR4, and TLR9 polymorphisms found relatively minor effects on asthma risk with the possible exception of the TLR2 Arg753Gln alteration, which may have a significant association with asthma risk . Thus, activation of innate immune responses through TLRs appears to have critical impact on the early stages of allergic disease, although the nature of this influence requires further study. TLR-BASED THERAPIES — There are several new therapies in use or development that utilize emerging knowledge of TLR biology. TLR7 agonists — TLR7 agonists have been found to be clinically useful in slowing the growth of malignancies and inhibiting viral replication. However, the precise mechanism of action of these agents remains unknown. Imiquimod — Imiquimod is a synthetic agonist of TLR7 that has been proven very effective as monotherapy for basal cell carcinoma when applied topically. It is also used in the treatment of actinic keratoses and genital warts. (See "Condylomata acuminata (anogenital warts): Treatment of vulvar and vaginal warts", section on 'Imiquimod' and "Treatment and prognosis of basal cell carcinoma at low risk of recurrence" and "Treatment of actinic keratosis".) Isatoribine — Isatoribine is another synthetic TLR7 agonist. In 12 adults with chronic hepatitis C infection who were otherwise untreated, seven daily injections of isatoribine reduced blood viral load measured by polymerase chain reaction . The therapy was well-tolerated, although the antiviral effect was modest. TLR9 and CpG DNA — Coadministration of oligodeoxynucleotides (ODNs) containing cytosine guanine dinucleotide (CpG) motifs during immunization enhances T helper type 1 (Th1) immune responses in animal models . These ODNs mimic bacterial DNA sequences and interact with TLR9. (See 'Specific TLRs' above.) ODNs are also being studied in human trials. Subcutaneous injection of ODNs alone into healthy volunteers leads to readily measurable increases of serum Th1 type cytokine levels (interleukin-12 [IL-12], interferon-alpha [IFN-alpha]), as well as cytokines generally associated with T helper type 2 (Th2) activation (interleukin-6 [IL-6]) . Vaccination — In a study of an ODN added to a hepatitis B vaccine (Engerix-B), recipients of the vaccine with added ODN had significantly faster and higher hepatitis B surface antibody responses in comparison with controls who received the vaccine alone . The recipients of the vaccine with ODN also had a significantly higher rate of adverse reactions, although these were mostly mild to moderate in severity. TLR4 agonists are used in several vaccines, including those against cervical cancer, shingles, and hepatitis B (brand names Cervarix, Shingrix, and Fendrix, respectively) . During the SARS-CoV-2 pandemic, highly effective TLR-activating mRNA vaccines against COVID-19 were developed, demonstrating the potential of pattern recognition receptors as adjuvants. (see "Hepatitis B virus immunization in adults" and "Hepatitis B virus immunization in infants, children, and adolescents"). Newborns and infants are more susceptible to infection, particularly by intracellular pathogens. The development of vaccines utilizing TLR agonists within nanoparticles shows promise in inducing adult-like immune responses in neonates, perhaps enhancing immune protection in this vulnerable population . Cancer therapy — CpG ODN are also being studied as agents for cancer therapy. These have been administered in combination with rituximab in a phase 1 trial in 20 patients with relapsed non-Hodgkin lymphoma . The therapy was well tolerated. Increased levels of mRNA for interferon-inducible genes were detected in the peripheral blood mononuclear cells of patients after receiving ODN. ODN have also been studied as an adjuvant for a cancer vaccine. Patients with newly diagnosed metastatic colon cancer and elevated serum carcinoembryonic antigen (CEA) levels were given a regimen combining chemotherapy with a cancer vaccine . The vaccine was comprised of a CEA-derived peptide with one of three adjuvants: ODN, granulocyte colony-stimulating factor (G-CSF), or autologous dendritic cells. The vaccines were of apparently equivalent immunogenicity. Eight of 17 (47 percent) patients developed cytotoxic anti-CEA T cell responses, despite having received concomitant immunosuppressive chemotherapy. Loading of the TLR7 agonist resiquimod onto nanoparticles shows promise in enhancing the immune response against tumor cells. Subcutaneous injection of resiquimod loaded nanoparticles into tumor-bearing mice have been shown to accumulate into tumor-draining lymph nodes where they can activate dendritic cells, leading to a cytotoxic T cell response . Allergen immunotherapy — Coupling of an ODN to an allergen has been evaluated as possible immunotherapy for atopic disease [114-116]. This strategy uses TLR9 as a potent inducer of Th1 T cell responses, thereby reducing Th2 or atopic responses: ●In one randomized trial, 19 adults allergic to ragweed received subcutaneous injections of a major ragweed pollen allergen (Amb a 1) coupled to an ODN . The injections were well tolerated, and the investigators demonstrated in vitro a shift of the peripheral blood T cell cytokine secretion profile from Th2 ("allergic") to Th1 ("nonallergic"). ●In two separate double-blind, placebo-controlled trials of 57 adults and 25 adults with ragweed allergy, subjects were randomly assigned to treatment using similar preparations of ragweed pollen allergen coupled to ODN, given by subcutaneous injection. In both trials, patients reported clinical benefits for up to two successive ragweed pollen seasons following a course of only six injections. ●Toll-like receptors (TLRs) belong to a class of molecules known as pattern recognition receptors (PRRs). The ligands for these receptors are components of pathogenic microbes called pathogen-associated molecular patterns (PAMPs). TLRs are part of the innate immune system, although they also modulate mechanisms that impact the development of adaptive immune responses. (See 'Role in innate immunity' above.) ●TLRs are expressed on leukocytes and various solid tissue cells. The cellular localization of TLRs varies. TLR2/1, TLR2/6, TLR4, TLR5, TLR10, and TLR11 are localized to cell surfaces, whereas TLR3, TLR7, TLR8, and TLR9 are localized within endosomes. (See 'Cellular and tissue distribution' above.) ●The structure of all of the TLRs is similar. Receptor structure, organization, ligands, and signaling are summarized in the table (table 1) and figure (figure 1). The final common pathway for TLR signaling involves transcription factors that regulate a multitude of genes, including those encoding important proinflammatory cytokines and type 1 interferons. (See 'Structure and function of TLRs' above.) ●Defects in proximal signaling molecules within TLR signaling pathways, including myeloid differentiation primary response protein 88 (MyD88) and interleukin-1 receptor-associated kinase 4 (IRAK4), have been implicated in primary immunodeficiency to a narrow spectrum of microbes, resulting in susceptibility to pyogenic bacterial infections. (See 'MyD88/IRAK4/IRAK1 deficiency' above.) ●UNC93B1 (UNC93 homolog B1), TLR3, toll/interleukin-1 (IL-1) receptor (TIR) domain-containing adapter-inducing interferon-beta (IFN-beta) (TRIF), tumor necrosis factor (TNF) receptor-associated factor 3 (TRAF3), and tank-binding kinase 1 (TBK1) mutations have been identified in patients with selective susceptibility to herpes simplex virus type 1 (HSV-1) encephalitis, severe influenza pneumonia and encephalopathy, and severe coronavirus disease 2019 (COVID-19). (See 'UNC93B1 deficiency, TLR3 mutations, TRIF deficiency, TRAF3 deficiency, and TBK1 deficiency' above.) ●Defects in more distal components of TLR signaling pathways (ie, nuclear factor [NF]-kappa-B essential modulator [NEMO], I-kappa-B-alpha, heme-oxidized IRP2 ubiquitin ligase-1 [HOIL-1], and HOIL-1 interacting protein [HOIP]) are associated with broader infectious susceptibilities (bacteria, mycobacteria, viruses, fungi, opportunistic organisms). Dedicator of cytokinesis 8 (DOCK8) deficiency impairs multiple cellular functions in a variety of cells types, leading to a combined immunodeficiency. (See 'TLR signaling defects in primary immunodeficiency' above.) ●TLR-based therapies in development or in use include the TLR7 agonists imiquimod and isatoribine. In addition, oligodeoxynucleotides (ODN) containing cytosine guanine dinucleotide (CpG) motifs, presumably through binding to TLR9, have been found to augment T helper type 1 (Th1) immune responses and have been applied to vaccination, cancer therapy, and immunotherapy for allergic disease. (See 'TLR-based therapies' above.) ●The use of TLR agonists in several vaccines in clinical use demonstrates their utility in the development of highly effective vaccines in the prevention human diseases. (See 'Vaccination' above.) ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges Francisco A Bonilla, MD, PhD, who contributed to earlier versions of this topic review. The UpToDate editorial staff also acknowledges E Richard Stiehm, MD, who contributed as a Section Editor to earlier versions of this topic review. آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
Gross National Product (GNP) is a measure of a country’s economic performance. It represents the total value of all final goods and services produced by the residents of a country within a specific period, regardless of the location of production. It includes domestic production and the overseas production by residents, but excludes domestic production by non-residents. Gross National Product (GNP) is pronounced as: /groʊs ˈnæʃənəl ˈprɒdʌkt/ - Gross National Product (GNP) Definition: GNP measures the total economic output of a country's residents, regardless of the location of the actual production. It combines the value of all finished goods and services produced by a country's residents, both domestically and internationally, within a set period of time. - GNP vs GDP: While Gross Domestic Product (GDP) measures the value of all goods and services within a country's borders, GNP includes all production by a country's residents, regardless of where that production takes place. Therefore, GNP is a more accurate reflection of a nation's income than GDP, particularly for countries with a significant number of citizens living abroad. - Uses of GNP: GNP is an important economic indicator, used to show a country's economic performance. Governments, businesses, and economists use GNP for planning and analysis in relation to growth, investments, and economic health. A rising GNP indicates a prospering economy while a declining GNP signals an economic downturn. Gross National Product (GNP) is an important economic measure because it represents the overall economic output of a nation’s residents, both domestically and abroad. It provides a comprehensive snapshot of a nation’s economic activity, indicating how successful the country is in generating wealth for its citizens. Unlike Gross Domestic Product (GDP), GNP also factors in the income earned by citizens who are abroad and domestic income generated by foreign residents. Therefore, GNP can present a clearer and more accurate measure of a nation’s overall economic health. The changes in GNP can be used to analyze economic performance over time, facilitating policy-making and business decisions. It is also often used for international comparisons. Gross National Product, commonly shortened to GNP, is a macroeconomic measurement used to gauge the overall economic health and vitality of a country’s economy. The purpose of GNP lies in its ability to provide a comprehensive snapshot of the economic output of a country, inclusive of the goods and services produced by its residents, both within the country’s borders and abroad. It is an important tool for economists, policymakers, and governments to ascertain the economic productivity and growth of a nation, regardless of where around the globe the businesses and individuals contributing to this production are located.The calculation and use of GNP are primarily leveraged to compare the economic performance of different nations, or consider the economic progress of a single nation over time. By providing a quantifiable measure of total production, GNP enables meaningful comparisons and evaluations of a nation’s growth and output. This information, in turn, aids governments in policy formulation surrounding areas such as taxation and economic strategy, and helps investors and business leaders make informed decisions. Therefore, GNP is not just a numerical statistic, but a crucial indicator of a nation’s economic well-being and a tool for strategic economic planning and decision making. 1. United States Economic Output: The Bureau of Economic Analysis in the United States reported a GNP of approximately $21.4 trillion for the year 2019. This value encapsulates the market value of all goods and services produced by residents of the U.S., regardless of their location, within the specified time period.2. Economic Comparison between Countries: For instance, according to the World Bank, Luxembourg boasted one of the world’s highest GNP per capita at around $69,000 in 2020, providing an excellent indication of the size and robustness of the nation’s economy in comparison to larger countries such as China or India whose total GNP is high, but per capita GNP is significantly lower due to larger population.3. Filipino Overseas Workers: The Philippines’ GNP is significantly impacted by the income generated by overseas Filipino workers. Due to a large amount of workers sending part of their income back home, the country’s GNP is often higher than its Gross Domestic Product (GDP). This situation vividly demonstrates how GNP takes into account the economic contributions of a country’s residents, regardless of where they are situated globally. Frequently Asked Questions(FAQ) What is Gross National Product (GNP)? Gross National Product (GNP) is the total market value of all final goods and services produced by the residents of a country in a specified period of time. It includes the domestic production of goods and services, as well as the goods and services produced abroad by the country’s residents. How is GNP different from GDP? While GNP measures the economic output generated by a country’s nationals regardless of their location, Gross Domestic Product (GDP) measures the total value of all goods and services produced within a country’s borders in a specific time period, regardless of who produced it. How is GNP used in finance and economics? GNP is an economic statistic that is used to understand the state of a country’s economy. It shows how productive a country’s residents are, and how it compares with other nations. It helps economists and investors to analyze the performance and make predictions about future performance. What are the components of GNP? The main components of GNP are consumption, government spending, investments made by industry, and net exports (which is the country’s total exports minus its total imports). It also includes the income earned by a country’s residents from overseas investments, minus the income earned within the domestic economy by overseas residents. Why is GNP important? GNP is a key indicator of a nation’s economic health. It provides an overview of the economic productivity of the residents of a country, both within their home country and abroad. This helps to guide policy makers, investors, and businesses in making informed decisions. How is GNP measured? GNP is measured by calculating the sum of personal consumption expenditures, gross private domestic investment, government consumption and gross investment, goods and services exports, goods and services imports, income receipts from the rest of the world, and income payments to the rest of the world. How often is GNP reported? GNP is typically reported on a quarterly and annual basis. These reports are widely studied and analyzed by economists, investors, and policy makers. Can GNP go down? What does it imply? Yes, GNP can decrease. A declining GNP indicates a contraction in a country’s economy and could be an indicator of a recession. It suggests that the residents of the country are producing less and could be due to various factors such as unemployment, reduction in consumer spending or drop in investment. What is Real GNP? Real GNP takes into account the price changes (inflation or deflation), allowing a more precise comparison by removing the effects of price inflation to reflect real volume of output. This provides a more accurate picture of a country’s economic situation over time. : Is higher GNP always beneficial? While a higher GNP often implies an increase in production and a stronger economy, it doesn’t necessarily mean improved living standards – for instance, if the growth is accompanied by environmental damage, increased inequality or depletion of resources. Plus, GNP doesn’t capture the ‘informal economy’ and non-market activities, or reflect societal well-being or progress. Related Finance Terms - Nominal GNP: The sum total of all goods and services produced by the citizens of an economy, measured at their current market prices, over a specific time period. - Real GNP: The total output produced by citizens of an economy, adjusted for inflation or deflation, to reflect changes in purchasing power. - GNP per Capita: This is the GNP of a country divided by its population. It’s a good measure to compare the economic performance of different countries. - Gross Domestic Product (GDP): This is a similar concept to GNP, though GDP measures the value of products and services produced within a country’s borders, regardless of the nationality of the producers. - Net National Product (NNP): This subtracts the depreciation of an economy’s capital goods from the GNP to provide a more accurate measure of actual productivity.
Pseudo Code in C Pseudo code in C is a simple way to write programming code in English. Pseudo-code is informal writing style for program algorithm independent from programming languages to show the basic concept behind the code. Pseudocode is not an actual programming language. So it cannot be compiled and not be converted into an executable program. It uses short or simple English language syntax to write code for programs before it is converted into a specific programming language. It is also useful in a program development process and the programmers will ensure that actual programming is likely to match design specifications. The errors finding at the pseudo-code stage is less costly than catching them later in the development process. It is possible to write programs that will convert a given pseudo-code language into a given programming language. In simple terms, pseudo-code = Natural Language + Programming Language. The pseudo code in C consists of words and phrases that make pseudo code looks similar to the program but not a program. Pseudo codes are written with respect to a programming language, but programming language syntax or grammar is not strictly followed. The pseudo-code is neither an algorithm nor a program. pseudo-code is a semi-formal description of the steps to be carried out by the computer, including Steps that are to be repeated and decisions that are to be made but it constructs/models and maybe even look like programming code. Pseudocode is made up of two words, ‘pseudo’ and ‘code’. Pseudo means imitation and code refer to instructions, written in a programming language. Pseudocode is also known as Program Design Language (PDL) or Structured has the following characteristics: A free syntax of natural language that describes a processing feature. A subprogram definition and calling techniques. Fixed syntax of keywords that provide for all structured constructs, data declarations and modularity characteristics. A data declaration facility. Pseudocode is a set of sequential written human language instructions, usually numbered, that is used to describe the actions a program will take when it is coded in a programming language. Notations of Pseudo Code in C The pseudo-code notation specifies operations that a machine can perform in as human-friendly (e.g., easy to read) way as possible while avoiding ambiguity. Pseudo code allows the designer to focus on the logic of the algorithm without being distracted by details of language syntax. Pseudocode describes the entire logic of the algorithm so that the implementation becomes a mere mechanical task of translating line by line into source code. Pseudocode is a generic way of describing an algorithm without using any specific programming language-related notations. Simply put, pseudo-code is an outline of a program, written in a form that can be easily converted into real programming statements. The Pseudocode uses plain English statements rather than symbols, to present the processes of a computer system. The ‘structured’ part of pseudo-code is a notation for representing three general programming constructs or structures namely sequence, selection and repetition (looping). These constructs represent the logic or flow of control in an algorithm. 1. Sequence Construct or Structure: As the name implies, in a sequence structure (construct), the instructions to be computed simply follow one another in a logical progression. The sequence construct indicates a processing step in a program. Sequence construct is a linear progression where one task is performed sequentially after another. Sequential control is indicated by writing one action after another, each action on a line by itself and all actions aligned with the logical indent. The actions are performed in the same sequence (top to bottom) in which they are written. 2. Selection (Decision): Selection is a process of deciding which choice is made between two or more alternative courses of action. In the selection construct, the execution of a set of statements is done according to a pre-specified condition. The selection structure is also known as decision-making structure because the decision to execute a particular set of the statement is made on the basis of the conditional statement. The selection structure is categorized into the following three types: This construct uses if and Then clauses to represent a condition as well as a set of statements. In the If clause, the conditional statement is written, while in Then clause the set of statements to be executed are specified. The execution of the statements specified in the Then clause occurs only if the condition is true. This construct is very much similar to the If-Then selection structure. The only difference between the two is that in If-Then-Else selection structure two sets of statements are specified. One set of statements is represented in the Then clause and another is represented in the Else clause. If the condition is given in If the clause is true, then all the statements specified in the Then clause is executed, otherwise, statements given in the Else clause are executed. A selection structure allows the program to make a choice between two alternate paths, whether it is true or false. The first statement of a selection structure is a conditional statement. IF (condition is True) THEN List of Actions List of Different Actions It is clear that if the condition is true, Action1 will be performed otherwise Action2 will be performed. After performing the list of actions, the control of the program moves on to the other actions in the process flow. In this selection construct, multiple sets of statements are specified. Each block of statements is associated with a value. The selection of a particular set of statements is made on the basis of the value of the variable given at the beginning of the selection structure. A case construct indicates a multiway branch based on many conditions. Case construct uses for keywords, Case Of, Others and EndCase, along with conditions that are used to indicate the various alternative. CASE Expression OF 1 Condition:Sequence 1 2 Condition:Sequence 2 N Condition: Sequence N 3. Repetition(Looping) Construct: Looping construct in pseudo-code is used when some particular task is to be repeated for a number of times according to the specified condition. When a sequence of statements is repeated against a condition, it is said to be in the loop. Using looping, the programmer avoids writing the same set of instructions again. The looping process can either be one time or multiple times until the desired output is obtained within a single program. In the repetition construct, only one set of multiple statements is specified. The same set of the statement is executed several times on the basis of the condition specified along with the structure. The various type of repetition structure is explained below: In the Do-While looping construct, a set of statements is given in the Do block and a condition is given in the Do block are executed till the given condition is true. At each instance of execution of block statements, the condition is checked. If the condition is true, then only the block statements are executed, otherwise, the repetition structure is terminated. DO WHILE Condition is True The Repeat-Until looping construct is similar to the Do-While repetition structure. In this structure, the repetitive execution of statements given in the Repeat clause occurs only when the condition given in the Until clause is false. UNTIL Condition is False Advantages and Disadvantages of Pseudo Codes Advantages Of Pseudo Code in C: Pseudo code is easier and simpler to understood by the programmers of all types. It cannot be compiled into an executable program. Compared to a flowchart, it is easier to modify the pseudo-code of program logic whenever program modifications are necessary. Converting a pseudo code to a programming language is very easy as compared with converting flowchart to a programming language. To develop a pseudo-code it requires less time and effort than other programming tools such as flowchart. pseudo-code is easier to write than writing a program in a programming language because pseudo-code as a method has only a few rules to follow. Disadvantages of Pseudo Code in C: Pseudocode is textual representation of an algorithm. It does not provide a graphical or visual representation. Therefore, sometimes, it becomes difficult to understand the complex written in Pseudocode. There are no standard rules to follow in using the Pseudo code in C. Different programmers use their own style of writing pseudo code and hence communication problems occur due to lack of standardization. For a beginner, it is more difficult to follow the logic or write pseudo code as compared to the flowchart.
However, because of the operation of extremely sophisticated telescopes like the Hubble or James Webb in the present period, NASA and ESA have never missed anything in the sky. Orion is being observed by these two space giants since their inception to explore the formation of stars and planets within the nebula. They have constructed images out of collected data and came up with the stunning revelation of the dramatic death and rebirth of stars within its cosmic belt. The data was collected by NASA's now-retired Spitzer Space Telescope; present Wide-Field Infrared Survey Explorer, newly named NEOWISE; and European Space Agency's retired Herschel Space observatory. The nebula has been named after the Greek mythological hunter who was killed by the sting of a scorpion. The runaway stars AE Aurigae, 53 Arietis, and Mu Columbae, which are currently ejecting from the nebula at speeds greater than 100 km/s (62 mi/s), may have lived within the Orion Nebula cluster two million years ago. A very young open cluster found in the Orion nebula known as Trapezium Cluster, this small cluster within the nebula consists of 4 stars with a diameter of 1.5 lightyears. The Trapezium cluster is part of a large nebula consisting of approximately 2800 stars with a diameter of 20 light years. From this, we can determine that the Orion cluster is around 40 light-years long. Within the star formation region, there are two caverns carved out by giant stars, which in the picture are also covered in heavy dust. As these massive stars emit radiation that is a million times stronger than the radiation of the sun, this radiation breaks apart the dust grains, creating the giant voids that create the nebula. The remaining dust is whittled away from the stars and nebula itself, this happens when a massive star dies. In the picture around the edge of the two cavernous regions, dust of different colors is being appeared and different colors is indicating the level of temperature and region where stars are dying and taking birth. Red indicates cold dust that reached temperatures of about -440 Fahrenheit. The red and green lights show data from the newly retired Herschel space telescope observatory that captured wavelengths of light in the far-infrared and microwave ranges, where cold dust radiates. The cold dust appears mostly on the outskirts of the dust cloud, away from the regions where stars form. In between the two hollow regions are orange filaments where dust condenses and forms new stars. Over time, these filaments may produce new giant stars that will once again reshape the region. The newly formed star will be going to eliminate a tremendous amount of cosmic radiation blasting away a million tonnes of material out of its own that was responsible for its own birth. Eventually, the new star will die and open the path for the formation of new stars out of the fertile ground that was plowed by a once-healthy star. So, this is how stars are born out of supernovas and this is how a new solar system is born out of the dust cloud within the supernova. the universe is full of such examples. The success of today's image is entirely going to the 17 years of struggle by the Spitzer Space Telescope. The Spitzer examined exosolar planets' temperatures, discovered a giant ring around Saturn, and assisted in spotting some of the most distant galaxies of the universe. The credit also goes to the WISE spacecraft which was launched in 2009 but was in a frozen state for years, recently it has been renamed NEOWISE after making it operational for further use. We, humans, are examining our universe and its celestial objects in every possible way we can, for that purpose we first build telescopes and then ground observation stations eventually very expensive space telescopes. Recently our new wonder James Webb is examining the universe to seek the answer to the formation of the Universe. Hopefully one day we will be able to find the answer behind the formation of our universe.
A supervolcano is one that explodes in (natch) supereruptions. Definitions vary, but usually we’re talking a magnitude-eight (M8) eruption: one trillion metric tons of ash and other debris filling at least 100 cubic miles, typically upchucked over the course of about a week. Picture 1,000 Mount Saint Helenses, or 8 Tamboras. Besides causing regional devastation, supereruptions affect global climate. An Indonesian super 74,000 years ago kicked off a thousand-year drought that some contend caused a human population crash. One shudders to think what a similar blow would do now. Yellowstone is both a supervolcano and a hotspot; the two don’t always go together. A hotspot is the business end of what’s known as a mantle plume, a stream of magma that rises hundreds of miles through a channel in the earth’s crust like the blob in a lava lamp. The Yellowstone plume head, 50 miles underground, is several hundred miles wide. Over time, the hot head melts the overlying crust, forming a smaller magma chamber. Yellowstone’s magma chamber is just a few miles down and contains partially melted granite viscous enough to trap gas, allowing pressure to build. Periodically the pressure cracks the surface, explosively ejecting gas and disintegrated rock into the surface world. After about a tenth of the chamber’s contents have erupted, pressure falls and the show’s over. Reheat and repeat. The Yellowstone hotspot has produced dozens of large eruptions over the past 16 million years, the last three within the Yellowstone volcanic field: two supers and one M7.4 lightweight that created 68 cubic miles of debris. They left overlapping giant calderas, or craters, each 10 to 50 miles wide. Since filled with lava and eroded, the calderas are inconspicuous and went unrecognized till the 1960s. These three big eruptions were 640,000 years ago, 660,000 years earlier, and 800,000 years before that. See a pattern? Lurid reports suggest we’re almost due, even overdue, but the pattern is illusory. Over the past 4.5 million years, large Yellowstone eruptions have come at irregular intervals of 300,000 to 2.4 million years. Furthermore, a series of smaller eruptions (relatively; one was Krakatoa-esque in magnitude) between 170,000 and 70,000 years ago ejected as much material as a super — perhaps enough to relieve the pressure, and danger, for a while. Israelis don’t see the effects of the siege in Gaza, or the way it was maintained during the six-month “calm.” Israeli journalists have a far easier time covering Mumbai than covering Gaza. What Israelis saw during the “calm” were Palestinian violations. Israel claimed that Hamas wasn’t keeping the agreement. That was true. It was also true that the Israeli government continued hoping, against all evidence, that the siege would provoke popular uprising against Hamas rule. Hamas regarded the calm as a failure in relieving siege conditions. When the six months ended, Hamas decided that those Israelis would only understand force. To a man with a hammer, as the saying goes, everything looks like a nail – especially to an angry man. With a little careful thinking, anyone on the Hamas side could have figured out that no Israeli politician wanted to agree to reduce the siege in response to rocket fire. That would be giving in. So brinkmanship led to both sides rushing over the brink into the abyss. Olmert, Livni, Barak and the collected generals apparently think that Hamas will agree to reduce violence as a result of the onslaught. A ten-second exercise in trying to imagine how Hamas leaders – or Gaza residents – see the situation leads to the opposite conclusion. It is possible that the new offensive will shatter the Hamas government. In that case we’ll have a collapsed state in Gaza, where there is absolutely no one interested in stopping rocket fire. Will Israel occupy the Strip again then? Does our triumvurate think that NATO will want the job? Outside of showing that we have a bigger hammer, what will the operation accomplish? Outside of the hammer, actually, Hamas did have some delicate tools in its tool chest. It could, for instance, have proposed indirect negotiations aimed at a two-state solution.That would have caught Israel’s leaders totally off guard, and undermined the political rationale for the siege. I guess that no one in the Gaza leadership considered this for 10 seconds. The voting has not yet closed, but kamikaze ballooning Brazilian priest Antonio de Carli looks a dead cert to secure the 2008 Darwin Awards crown for the most impressive contribution to improving the gene pool by removing himself from it. The Roman Catholic daredevil decided back in April it was a really bright idea to attempt to break the record for the most time spent dangling under a load of helium balloons (19 hours), to “raise money for a spiritual rest-stop for truckers” in the coastal city of Paranagua. Despite being an experienced skydiver and packing a GPS, mobile phone and parachute, he was quickly blown out to sea and, although subsequently able to call for help, was apparently unable to provide his position because he couldn’t work the GPS unit. His body was recovered three months later off the south-east coast of Brazil. The full list of 2008 nominations is right here What do you do if you’re high altitude testing and you see one of Google’s Streetview cars coming? “Hans, run for the tarps!” The boys at Garage419 were doing a little research on Colorado’s Mount Evans Scenic Byway using Google’s Streetview and something interesting caught their attention. The Mount Evans Scenic Byway climbs 7,000 feet in just 28 miles reaching a 14,264-foot summit, making this the highest paved road in America and one frequently used by manufacturers for high-altitude testing. It’s obvious now why they were checking it out. It is the ultimate in swimming lessons as Paula the baby hippo struggles to keep up with her mother Kathi. If you already know his name, chances are you’ve been doing something illegal. In 2002, four intrepid researchers filed a Freedom of Information Act. But they weren’t looking for information on Guantanamo or revelations from Cheney’s lair. All they wanted was the FDA’s drug analysis data. Taxpayer funded research. They got it. The studies examined were conducted between 1987 and 1999 andcovered Prozac, Paxil, Zoloft, Celexa, Serzone, and Effexor. They found, on average, that placebos were 80 percent as effective as the drugs. Put aside the surprising results: Why didn’t the public know about these studies? Why wasn’t the medical community informed? The answer, as Marcia Angell argues in an important New York Review of Books article, is that our system of clinical evaluation is so riddled with conflicts of interests that “it is simply no longer possible to believe much of the clinical research that is published, or to rely on the judgment of trusted physicians or authoritative medical guidelines.” Many of Britain’s biggest companies are preparing year-end accounts that show their pension schemes moved into surplus last year despite the collapse in world markets, which wiped hundreds of billions from their assets. The latest figures from the pensions advisers Aon Consulting show that a steep decline in the FTSE 100 over last year and a sharp drop in commercial property values has sent most final-salary schemes into crisis and pushed fund deficits to new lows. According to government figures, company pension fund deficits rose in the 12 months to November from £58bn to £155bn. Aon Consulting warned that the figures underestimated the problem and pension funds had suffered a £226bn loss on their investments in the year to October. However, accounting rules – which critics argue distort company pension scheme fund values – will show a rise in assets. For the top 200 companies in Britain, that will mean a £13bn surplus at the end of 2008. Aon says the top 100 firms have seen a £5bn improvement over the last year, based on current accounting rules. Officials ordered nine Muslim passengers, including three young children, off an AirTran flight headed to Orlando from Reagan National Airport yesterday afternoon after two other passengers overheard what they thought was a suspicious remark. I found this when investigating an intermittent latency issue caused by vibration on disk missing a drive bracket screw (which Adam found once before). After reinserting the disk, I enabled additional Analytics to get a good trace of the effect – but it wasn’t reproducing. I was trying to figure out why, and wondering how close the disk was to the vibration point – when I shouted at it to give it some extra vibration. This worked better than expected, and caused issues in all the disks I was shouting at, not just the missing screw one. I was using the Analytics by-disk breakdown to map where I was shouting at (although in the video I shouted a bit too loud, and vibrated most disks in both JBODs). If I can get the missing screw issue to reproduce, I’ll post a blog entry with the screenshots. A judge was interviewing a woman regarding her pending divorce, and asked, “What are the grounds for your divorce?” She replied, “About four acres and a nice little home in the middle of the property with a stream running by.” “No,” he said, “I mean what is the foundation of this case?” “It is made of concrete, brick and mortar,” she responded. “I mean,” he continued, “What are your relations like?” “I have an aunt and uncle living here in town, and so do my husband’s parents.” He said, “Do you have a real grudge?” “No,” she replied, “We have a two-car carport and have never really needed one.” “Please,” he tried again, “is there any infidelity in your marriage?” “Yes, both my son and daughter have stereo sets. We don’t necessarily like the music, but the answer to your questions is yes.” “Ma’am, does your husband ever beat you up?” “Yes,” she responded, “about twice a week he gets up earlier than I do.” Finally, in frustration, the judge asked, “Lady, why do you want a divorce?” “Oh, I don’t want a divorce,” she replied. “I’ve never wanted a divorce. My husband does. He said he can’t communicate with me!” Were an alien to pick up our news channels, it would conclude that human civilization depended on the production and purchase of cheap plastic rubbish. First came the concern that we might talk ourselves into not spending enough, then the fear that the banks wouldn’t lend us the money to spend even if we wanted to. In November, our governments borrowed money and gave it to us in the hope that we’d catch on. Are we really so dependent on consumption? In the short run, yes. Economists worry about a sharp fall in consumer spending, because when demand for goods falls, so does demand for labor. Our desire to spend less is quickly revealed as a desire to spend less hiring each other (and our friends in China) to make things. Result: economic collapse, unemployment, misery. In the long run, the picture is completely different. We earn—this is a very rough average—twice what our parents did when they were our age. When today’s teenagers are in their 40s, there is no reason why they shouldn’t decide to enjoy their increased prosperity by working less instead of earning more. Rather than being twice as rich as their parents, they could be no richer but start their weekends on Wednesday afternoon. If this were a gradual process, mass unemployment would not result. People would simply earn less, spend less, wear a few more secondhand clothes, and spend more time reading or going for walks. “It’s absolutely bizarre. We now have trains that can’t let the passengers out because they fail to pick up signals from outer space.” The Bush administration’s infatuation with presidential power has finally pushed the country over a constitutional precipice. As of New Year’s Day, ongoing combat in Iraq is illegal under US law. In authorizing an invasion in 2002, Congress did not give President Bush a blank check. It explicitly limited the use of force to two purposes: to “defend the national security of the US from the threat posed by Iraq” and “enforce all relevant UN Security Council resolutions.” Five years after the fall of Saddam Hussein, the government of Iraq no longer poses a threat. Our continuing intervention has been based on the second clause of Congress’ grant of war-making power. Coalition troops have been acting under a series of Security Council resolutions authorizing the continuing occupation of Iraq. But this year, Bush allowed the UN mandate to expire on December 31 without requesting a renewal. At precisely one second after midnight, Congress’ authorization of the war expired along with this mandate. Bush is trying to fill the legal vacuum with the new Status of Forces Agreement (SOFA) he signed with the Iraqis. But the president’s agreement is unconstitutional, since it lacks the approval of Congress. Bush even refused to allow Congress access to the terms of the deal. He’s still out of a job, and can’t find a publisher for his book. Alberto Gonzales, who has kept a low profile since resigning as attorney general nearly 16 months ago, said he is writing a book to set the record straight about his controversial tenure as a senior official in the Bush administration. Mr. Gonzales has been portrayed by critics both as unqualified for his position and instrumental in laying the groundwork for the administration’s “war on terror.” He was pilloried by Congress in a manner not usually directed toward cabinet officials. “What is it that I did that is so fundamentally wrong, that deserves this kind of response to my service?” he said during an interview Tuesday, offering his most extensive comments since leaving government. Uhm, let’s see. There is the politicalization of the Justice Department, including widespread employment discrimination, and the infamous US Attorney scandal. There was his racing to the hospital bed of an extremely ill John Ashcroft to get the man, still recovering from major surgery, to sign a re-authorization of secret wire tapping that the AG’s temporary fill-in, James Comey, wouldn’t sign. He signed torture memos. He destroyed the DoJ’s Civil Rights Division. Things were so bad, Justice’s own Inspector General investigated him on charges of perjury and obstruction, not exactly exonerating Gonzales. We can add warrantless-searches, the Military Commissions Act, GITMO torture, abandoning the Geneva Conventions and shocking tolerance for corruption of a department that, for the benefit of the nation and the rule of law, must maintain its independence, to the list. Add in almost no redeeming qualities. As Adam Cohen, chief legal analyst for CBS News wrote not long ago, “He brought shame and disgrace to the Department because of his lack of independent judgment on some of the most vital legal issues of our time. And he brought chaos and confusion to the department because of his lack of respectable leadership over a cabinet-level department among the most important in the nation. “He neither served the longstanding role as “the people’s attorney” nor fully met and tamed his duties and responsibilities to the constitution. He was a man who got the job not because he was supremely qualified or notably well-respected among the leading legal lights of our time, but because he had faithfully and with blind obedience served President George W. Bush for years in Texas (where he botched clemency memos in death penalty cases) and then as White House counsel (where he botched the nation’s legal policy on torture).” “We would like to sputter in shock and disbelief. General Motors Acceptance Corp. (GMAC) lost $5B in the 9 months ending September 2008 (on an operating basis). It has $100B in subprime and nonconforming mortgages through its ResCap subsidiary, and the government just lent them $5B at an 8% interest rate. In addition, General Motors (GM) just announced a 0% financing option to car buyers. So it turns out that we are now subsidizing a globally uncompetitive carmaker that does not understand what qualifies as a subprime FICO score and is offering 0% loans financed by a government (taxpayer) investment that costs 8%. We guess they are hoping to make it up on volume.” One point, highlighted by Tim Lee of the consultancy pi Economics in Stamford, Connecticut, is that the $50 billion headline figure is about as inflated as California real estate prices were a year ago. That $50 billion is likely to turn out to be not the amount lost but the amount people wrongly thought they had. It is likely that the actual strategy followed by Madoff could return little more than Treasury notes minus fees; in other words he could make for you what you could get for yourself with no help but then pay himself handsomely for the gymnastics. That implies that a lot – for long-time investors, the vast majority – of the “money” invested and now “lost” with Madoff was about as notional as a credit default swap contract with a man you met outside the bus station downtown. Much of the money never existed, other than on the attractive and no-doubt glossy statements sent by Madoff. It was simply what people would have had if he had been a genie. And it is in this way that we are all Ponzi limited partners: We too thought our retirement funds and houses were growing miraculously, though ours was an illusion fueled by debt rather than fraud, and we too made plans based on those asset values that now stand in ruins. “The financial system as a whole has had the characteristics of a Ponzi scheme if we look at it fundamentally,” said Lee, who was very early in warning about deflation. Back in 1998, when the small company I worked for was about to be bought by Cap Gemini, there was talk about getting all the contracts “in line” with what was standard within Cap, and we would be required to sign new contracts. On of the advantages of signing the new contract was, as I was told, the pension fund. I asked how they were going to compensate me for the losses I would suffer. They didn’t understand my question, so I expanded: “you’re going to take money out of my paycheck and put it in a fund where I will never see it again. Thus, I lose money. How are you going to compensate for that loss?” All I got was “but, but…. it’s a pension fund, you’re going to get paid when you retire!”. I told them I didn’t believe I ever would, unless they could guarantee me with their personal wealth that, for example, tax laws would never change. I must admit I never mentioned ponzi schemes, and I didn’t expect to be right about all this before at least 2020, but I’d really like to ask the same people if they’re finally beginning to understand what I’m talking about – although I don’t expect much progress on their part. It soon became clear that they were just after the customers of the company, didn’t give a shit about the employees and were willing to say anything to get us to sign. So I soon allowed myself to be lured away (Hi, Jan-Mark!) to another company. Austria’s government said Wednesday it will take over management of Bank Medici but will not supply it with funds, after the Vienna-based bank suffered large losses on investments with the alleged New York Ponzi scheme run by Bernard Madoff. Austrian authorities began investigating Bank Medici earlier this month, following reports it had placed about $2.1 billion in funds controlled by Mr. Madoff, according to people familiar with the matter. On Dec 11, prosecutors announced Mr. Madoff’s arrest on charges he defrauded investors of up to $50 billion in a Ponzi scheme. Bank Medici focused almost entirely on achieving commissions from customers investing in two funds that in turn invested heavily with Mr. Madoff, Mr. Grubelnik said. “This is a business model without a future,” he said. A spokesman for the Austrian National Bank said it expects only minimal fallout from the trouble at Bank Medici, because the bank wasn’t involved in traditional banking operations. Government officials concluded turbulent discussions with Bank Medici that led to the resignation of the small bank’s entire board of directors, the spokesman said. So they did no “traditional banking operations” and only dealt with two Madoff funds. Yet they were allowed to call themselves “bank”. Sounds like the only reason for this company to be a “bank” is to get the 100k EUR coverage of each account by the government. In other words, they’re just thieves. I learned in Iraq that the No. 1 reason foreign fighters flocked there to fight were the abuses carried out at Abu Ghraib and Guantanamo. Our policy of torture was directly and swiftly recruiting fighters for al-Qaeda in Iraq. The large majority of suicide bombings in Iraq are still carried out by these foreigners. They are also involved in most of the attacks on U.S. and coalition forces in Iraq. It’s no exaggeration to say that at least half of our losses and casualties in that country have come at the hands of foreigners who joined the fray because of our program of detainee abuse. The number of U.S. soldiers who have died because of our torture policy will never be definitively known, but it is fair to say that it is close to the number of lives lost on Sept. 11, 2001. How anyone can say that torture keeps Americans safe is beyond me — unless you don’t count American soldiers as Americans. In Iraq, we lived the “ticking time bomb” scenario every day. Numerous Al Qaeda members that we captured and interrogated were directly involved in coordinating suicide bombing attacks. I remember one distinct case of a Sunni imam who was caught just after having blessed suicide bombers to go on a mission. Had we gotten there just an hour earlier, we could have saved lives. Still, we knew that if we resorted to torture the short term gains would be outweighed by the long term losses. I listened time and time again to foreign fighters, and Sunni Iraqis, state that the number one reason they had decided to pick up arms and join Al Qaeda was the abuses at Abu Ghraib and the authorized torture and abuse at Guantánamo Bay. My team of interrogators knew that we would become Al Qaeda’s best recruiters if we resorted to torture. Torture is counterproductive to keeping America safe and it doesn’t matter if we do it or if we pass it off to another government. The result is the same. And morally, I believe, there is an even stronger argument. Torture is simply incompatible with American principles. George Washington and Abraham Lincoln both forbade their troops from torturing prisoners of war. They realized, as the recent bipartisan Senate report echoes, that this is about who we are. We cannot become our enemy in trying to defeat him. If you desire high-resolution images of the Earth, the good folks at Unearthed Outdoors have made available the 250m True Marble image set for a free download with a Creative Commons Attribution 3.0 license. It’s a map of the Earth made up of 32 tiles, where each tile is a 21,000 pixel square, available in png and tif formats. There’s also a series of smaller files that may be more useful — in case you don’t need a map of the Earth that ends up being 84,000 pixels tall and 168,000 pixels across. Printed at 600 dpi, that’s about 12 feet by 24 feet!
Cryptography basics: Symmetric key encryption algorithms Scrambling plaintext into ciphertext is essential to ensure data cannot be read or used by the wrong people. Learn the basics of symmetric key encryption algorithms here. Cryptography is one area of information security that is well known but often not well understood. The basics of the algorithms may stay the same, but as attacks and infections evolve, so too must the algorithms that are key to keeping confidential information safe. In this excerpt from Chapter 8 of Computer Security Fundamentals by author Chuck Easttom, published by Pearson, immerse yourself in the functionalities of symmetric key encryption, also known as single-key encryption. Take a deep dive into the various symmetric key encryption algorithms, from the antiquated Data Encryption Standard, or DES, to its replacement Advanced Encryption Standard, or AES. Easttom offers an in-depth look at the math behind symmetric key algorithms, as well as their variants, from Triple DES to RC4 (Rivest Cipher 4) to Skipjack. But, before jumping in, Easttom suggests reviewing some key encryption terms: - Key: Bits that combine with plaintext to encrypt it. - Plaintext: Unencrypted text. - Ciphertext: Encrypted text. - Algorithm: A mathematical process for doing something. Computer Security Fundamentals Download a PDF of Chapter 8. Single-Key (Symmetric) Encryption Basically, single-key encryption means that the same key is used to both encrypt and decrypt a message. This is also referred to as symmetric key encryption. There are two types of symmetric algorithms (or ciphers): stream and block. A block cipher divides the data into blocks (often 64-bit blocks, but newer algorithms sometimes use 128-bit blocks) and encrypts the data one block at a time. Stream ciphers encrypt the data as a stream of bits, one bit at a time. Data Encryption Standard Data Encryption Standard, or DES, was developed by IBM in the early 1970s and published in 1976. Yes, it is old, and it is no longer considered secure; however, it is worthy of study for two reasons. The first reason is that DES was the first modern symmetric cipher. The second reason is that the general structure, often called a Feistel function or Feistel cipher, is still used in many modern algorithms. DES is a block cipher, which divides the plain text into 64-bit blocks and encrypts each block. The basic concept is as follows: At the time DES was released, it was a marvelous invention. Even today the algorithm is still sound. However, the small key size, 56 bits, is not good enough to defend against brute-force attacks with modern computers. Many cryptography textbooks and university courses use DES as the basic template for studying all block ciphers. We will do the same and give this algorithm more attention than most of the others in this chapter. For those new to security and cryptography, the brief facts listed earlier are enough. However, for those who want to delve a bit deeper, let's examine the details of the DES algorithm. DES uses a 56-bit cipher key applied to a 64-bit block. There is actually a 64-bit key, but 1 bit of every byte is used for error correction, leaving just 56 bits for actual key operations. DES is a Feistel cipher with 16 rounds and a 48-bit round key for each round. They are called Feistel ciphers (also Feistel functions) after Horst Feistel, the inventor of the concept, and the primary inventor of DES. All Feistel ciphers work in the same way: They divide the block into two halves, apply a round function to one of those halves, and then swap the halves. This is done each round. The primary difference between different Feistel ciphers is what exactly occurs within the round function. The first issue to address is the key schedule. A key schedule, which all block ciphers use, is a simple algorithm that will take the initial key the two parties derived and generate from that a slightly different key each round. DES does this by taking the original 56-bit key and slightly permuting it each round so that each round is applying a slightly different key but one that is based on the original cipher key. To generate the round keys, the 56-bit key is split into two 28-bit halves, and those halves are circularly shifted after each round by 1 or 2 bits to provide a different subkey each round. During the round key generation portion of the algorithm (recall that this is referred to as the key schedule) each round, the two halves of the original cipher key (the 56 bits of key that the two endpoints of encryption must exchange) are shifted a specific amount. The end result is that for each of the 16 rounds of DES, the key is actually a little different from the key used in the previous round. All modern symmetric ciphers do something like this to improve the security of the cipher. Once the round key has been generated for the current round, the next step is to address the half of the original block that is going to be input into the round function. Recall that the two halves are each 32 bits. The round key is 48 bits. This means that the round key does not match the size of the half block it is going to be applied to. You cannot really XOR a 48-bit round key with a 32-bit half block unless you simply ignore 16 bits of the round key. If you did so, you would basically be making the round key shorter and thus less secure, so this is not a good option. The 32-bit half needs to be expanded to 48 bits before it is XORed with the round key. This is accomplished by replicating some bits so that the 32-bit half becomes 48 bits. This expansion process is actually quite simple. The 32 bits that are to be expanded are broken into 4-bit sections. The bits on each end are duplicated. If you divide 32 by 4, the answer is 8. So there are 8 of these 4-bit groupings. If you duplicate the end bits of each grouping, that will add 16 bits to the original 32, thus providing a total of 48 bits. It is also important to keep in mind that it was the bits on each end that were duplicated. This will be a key item later in the round function. Perhaps this example will help you understand what is occurring at this point. Let us assume 32 bits, as shown here: Now divide this into 8 sections of 4 bits each, as shown here: 1111 0011 0101 1111 1111 0001 0101 1001 Now each of these has its end bits duplicated, as you see here: 1111 becomes 111111 0011 becomes 000111 0101 becomes 001011 1111 becomes 111111 1111 becomes 111111 0001 becomes 000011 0101 becomes 001011 1001 becomes 110011 The resulting 48-bit string is now XORed with the 48-bit round key. Now you are done with the round key. Its only purpose was to XOR with the 32-bit half. It is now discarded, and on the next round another 48-bit round key will be derived from the two 28-bit halves of the 56-bit cipher key, using the key schedule we previously described. Now we have the 48-bit output of the XOR operation. But this still does not seem to work. Don't we need 32 bits rather than 48? That 48 bits is now split into 8 sections of 6 bits each. Each of those 6-bit sections is going to be input into an s-box (substitution box), and only 4 bits will be output. The 6-bit section is used as the input to an s-box, which is a table that takes input and produces an output based on that input. In other words, it is a substitution box that substitutes new values for the input. There are eight different s-boxes for DES, but below you can see one of them: An s-box is really just a hard-coded lookup table. The 2 bits on either end are shown in the left column, and the 4 bits in the middle are shown in the top row. They are matched, and the resulting value is the output of the s-box. For example, with the previous demonstration numbers we were using, our first block would be 111111. So you find 1xxxx1 on the left and x1111x on the top. The resulting value is 3 in decimal, or 0011 in binary. Recall that during the expansion phase we simply duplicated the outermost bits, so when we come to the s-box phase and drop the outermost bits, no data is lost. Since each s-box outputs 4 bits and there are 8 s-boxes, the result is 32 bits. That 32 bits is now exclusively ORed with the other half of the original block. Recall that we did nothing with that half originally. Now the two halves are swapped. If you are new to cryptography, all of this might seem a bit confusing, even with the explanations provided. Many readers will need to reread this section a few times for it to become totally clear. Triple DES (3DES) was created as a replacement for DES. At the time, the cryptography community was searching for a viable alternative. While that was still being worked on, 3DES was created as a stop-gap measure. It essentially applies DES three times with three different keys, thus the name 3DES. There were variations of 3DES that used only two keys. The text was first encrypted with key A. The cipher text from that operation was then encrypted with key B. Then the cipher text from that operation was encrypted, this time reusing key A. The reason for this reuse is that creating good cryptographic keys is computationally intensive. Advanced Encryption Standard (AES) was the algorithm eventually chosen to replace DES. It is a block cipher that works on 128-bit blocks. It can have one of three key sizes: 128, 192, or 256 bits. The U.S. government selected AES to be the replacement for DES, and it is now the most widely used symmetric key algorithm. AES, also known as Rijndael block cipher, was officially designated as a replacement for DES in 2001 after a 5-year process involving 15 competing algorithms. AES is designated as FIPS 197. Other algorithms that did not win that competition include such well-known algorithms as Twofish. The importance of AES cannot be overstated. It is widely used around the world and is perhaps the most widely used symmetric cipher. Of all the algorithms in this chapter, AES is the one you should give the most attention to. As mentioned earlier, AES can have three different key sizes: 128, 192, and 256 bits. The three different implementations of AES are referred to as AES 128, AES 192, and AES 256. The block size can also be 128, 192, or 256 bit. It should be noted that the original Rijndael cipher allowed for variable block and key sizes in 32-bit increments. However, the U.S. government uses these three key sizes with a 128-bit block as the standard for AES. This algorithm was developed by two Belgian cryptographers, John Daemen and Vincent Rijmen. John Daeman is a Belgian cryptographer who has worked extensively on the cryptanalysis of block ciphers, stream ciphers, and cryptographic hash functions. For those new to security, the brief description given so far is sufficient. However, we will explore the AES algorithm in more detail. Just as with the details of DES, this may be a bit confusing to some readers at first glance and may require a few rereads. Rijndael uses a substitution-permutation matrix rather than a Feistel network. The Rijndael cipher works by first putting the 128-bit block of plain text into a 4-byte-by-4-byte matrix, termed the state, that changes as the algorithm proceeds through its steps. The first step is to convert the plain text block into binary and then put it into a matrix, as shown in Figure 8.3. Once you have the original plain text in binary, placed in the 4-byte-by-4-byte matrix, the algorithm consists of a few relatively simple processes that are used during various rounds. The processes are described here: - AddRoundKey: In this process, each byte of the state is exclusively ORed with the round key. Just as with DES, there is a key schedule algorithm that slightly changes the key each round. - SubBytes: This involves substitutions of the input bytes (which are the output from the AddRoundKey phase). This is where the contents of the matrix are put through the s-boxes. Each of the s-boxes is 8 bits. - ShiftRows: This is a transposition step where each row of the state is shifted cyclically a certain number of steps. In this process, the first row is left unchanged. Every byte in the second row is shifted 1 byte to the left (and the far left wraps around). Every byte of the third row is shifted 2 to the left, and every byte of the fourth row is shifted 3 to the left (again with the far left wrapping around). This is shown in Figure 8.4. Notice that in this figure that the bytes are simply labeled by their row and then a letter, such as 1a, 1b, 1c, 1d. - MixColumns: This is a mixing operation that operates on the columns of the state, combining the 4 bytes in each column. In the MixColumns process, each column of the state is multiplied with a fixed polynomial. Each column in the state (remember the matrix we are working with) is treated as a polynomial within the Galois field (28). The result is multiplied with a fixed polynomial c(x) = 3x3 + x2 + x +2 modulo x4 + 1. The MixColumns process can also be viewed as a multiplication by the shown particular MDS matrix in the finite field GF(28). These processes are executed multiple times in the Rijndael cipher. For 128-bit keys, there are 10 rounds. For 192-bit keys, there are 12 rounds. For 256-bit keys, there are 14 rounds. These last few steps may be leaving you a bit confused if you don't have a background in number theory. You may be asking questions like "What is a Galois field?" and "What is a fixed polynomial?" A general overview of the math needed to understand this is provided in the next section. A group is an algebraic system consisting of a set, an identity element, one operation, and its inverse operation. Basically, groups are ways to limit math operations, such as addition, to specific sets of numbers. There are several specialized types of groups, briefly described here: - An abelian group, or commutative group, has an additional axiom a + b = b + a if the operation is addition or ab = ba if the operation is multiplication. - A cyclic group has elements that are all powers of one of its elements. - A ring is an algebraic system consisting of a set, an identity element, two operations, and the inverse operation of the first operation. - A field is an algebraic system consisting of a set, an identity element for each operation, two operations, and their respective inverse operations. This brings us to the Galois group, or Galois field. GF(p) for any prime, p, this Galois field has p elements that are the residue classes of integers modulo p. That prime number p is the defining element for the field. Now, this is obviously a brief description and does not attempt to get into details. A thorough study of group theory would be needed to get into more detail. Blowfish is a symmetric block cipher. It uses a variable-length key ranging from 32 to 448 bits. Blowfish was designed in 1993 by Bruce Schneier. It has been analyzed extensively by the cryptography community and has gained wide acceptance. It is also a noncommercial (free of charge) product, thus making it attractive to budget-conscious organizations. All the other symmetric algorithms we have discussed have been block ciphers. RC4 is a stream cipher developed by Ron Rivest. RC is an acronym for Ron's Cipher, or sometimes Rivest's Cipher. There are other RC versions, such as RC5 and RC6. Serpent has a block size of 128 bits and can have a key size of 128, 192, or 256 bits, much like AES. The algorithm is also a substitution-permutation network (like AES). It uses 32 rounds working with a block of four 32-bit words. Each round applies one of eight 4-bit to 4-bit s-boxes 32 times in parallel. Serpent was designed so that all operations can be executed in parallel. This is one reason it was not selected as a replacement for DES. At the time it was created, many computers had difficulty with parallel processing. However, modern computers have no problem with parallel processing, so Serpent is once again an attractive choice. Originally classified, the Skipjack algorithm was developed by the National Security Agency (NSA) for the clipper chip. The clipper chip was a chip with built-in encryption; however, the decryption key would be kept in a key escrow in case law enforcement needed to decrypt data without the computer owner's cooperation. This feature made the process highly controversial. Skipjack uses an 80-bit key to encrypt or decrypt 64-bit data blocks. It is an unbalanced Feistel network with 32 rounds. Unbalanced Feistel simply means a Feistel cipher wherein the two halves of plain text for each block are not the same size. For example, a 64-bit block might be divided into a 48-bit half and a 16-bit half rather than two 32-bit halves. Modification of Symmetric Methods Just as important as understanding symmetric ciphers is understanding how they are implemented. There are some common modes that can affect how a symmetric cipher functions. The most basic encryption mode is the electronic codebook (ECB) mode. With ECB, a message is divided into blocks, and each block is encrypted separately. The problem is that if you submit the same plain text more than once, you always get the same cipher text. This gives attackers a place to begin analyzing the cipher to attempt to derive the key. Put another way, ECB is simply using the cipher exactly as it is described, without attempting to improve its security. Cipher Block Chaining When using cipher block chaining (CBC) mode, each block of plain text is XORed with the previous cipher text block before being encrypted. This means there is significantly more randomness in the final cipher text, making it much more secure than electronic codebook mode. It is the most common mode. There really is no good reason to use ECB over CBC if both ends of communication can support CBC. CBC is a strong deterrent to known plain text attacks, a cryptanalysis method we will examine later in this chapter. The only issue with CBC is the first block. There is no preceding block of cipher text to XOR the first plain text block with. It is common to add an initialization vector (IV) to the first block so that it has something to be XORed with. The initialization vector is basically a pseudo-random number, much like the cipher key. Usually an IV is only used once, and it is thus called a nonce (for "number used only once"). The CBC mode is actually fairly old. It was introduced by IBM in 1976. About the author Dr. Chuck Easttom is the author of 26 books, including several on computer security, forensics and cryptography. He has also authored scientific papers on digital forensics, cyberwarfare, cryptography and applied mathematics. He is an inventor with 16 computer science patents. He holds a doctorate of science in cybersecurity (dissertation topic: a study of lattice-based algorithms for post-quantum cryptography) and three master's degrees (one in applied computer science, one in education and one in systems engineering). He also holds 44 industry certifications (CISSP, CEH, etc.) He is a frequent speaker at cybersecurity, computer science and engineering conferences. He is a distinguished speaker and senior member of the Association for Computing Machinery and a senior member of the Institute of Electrical and Electronics Engineers. Dr. Easttom is also a reviewer for five scientific journals and editor in chief for the American Journal of Science & Engineering. You can find out more about Dr. Easttom and his research at his website.
The Trail of Tears ¢Jacksons Democrats were committed to western expansion, but such expansion meant confrontation with the Indians who inhabited the land east of the Mississippi. ¢The Society for Propagating the Gospel Among Indians was founded in 1787 in order to Christianize Indians. ¢The five civilized tribes were the Cherokees, Creeks, Choctaws, Chickasaws, and Seminoles. President Jackson wanted to move the Indians so the white men could expand. ¢In 1830, Congress passed the Indian Removal Act. It moved more than 100,000 Indians living east of the Mississippi to reservations west of the Mississippi. The five civilized tribes were hardest hit. ¢Black Hawk, who led Sauk and Fox braves from Illinois and Wisconsin, resisted the eviction. ¢The Seminoles in Florida retreated to the Everglades, fighting for several years until they retreated deeper into the Everglades. The Bank War ¢President Andrew Jackson despised the Bank of the United States because he felt it was very monopolistic. ¢The Bank of the United States was a private institution, accountable not to the people, but to its elite circle of investors. The bank minted gold and silver coins. Nicholas Biddle, the president of the Bank of the United States, held an immense and possibly unconstitutional amount of power over the nations financial affairs. ¢The Bank War erupted in 1832 when Daniel Webster and Henry Clay presented Congress with a bill to renew the Banks charter. Clay pushed to renew the charter in 1832 to make it an issue for the election of that year. He felt that if Jackson signed off on it, then Jackson would alienate the people of the West who hated the Bank. If Jackson vetoed it, then he would alienate the wealthy class of the East who supported the Bank. Clay did not account for the fact that the wealthy class was now a minority. Jackson vetoed the bill calling the Bank unconstitutional. ¢The veto showed that Jackson felt that the Executive Branch had more power than the Judicial Branch in determining the Constitutionality of the Bank of the United States. Old Hickory Wallops Clay in 1833 ¢A third party entered the election in the election of 1832: The Anti-Masonic party. The party opposed the Masonic Order, which was perceived by some as people of privilege and monopoly. Although Jackson was against monopolies, he was a Mason himself; therefore the Anti-Masons were an anti-Jackson party. It gained support from evangelical Protestant groups. ¢The Jacksonians were opposed to all government meddling in social and economic life. ¢Andrew Jackson was reelected in the election of 1832. Burying Biddles Bank ¢The Bank of the United Statess charter expired in 1836. Jackson wanted to make sure that the Bank would be exterminated. ¢In 1833, 3 years before the Banks charter ran out, Jackson decided to remove federal deposits from its vaults. Jackson proposed depositing no more funds in the bank and he gradually shrunk existing deposits by using the funds to pay for day-to-day expenditures of the government. ¢The death of the Bank of the United States left a financial vacuum in the American economy. Surplus federal funds were placed in several dozen state banks that were political supportive of Jackson. ¢Smaller, wildcat banks in the west had begun to issue their own currency. But this wildcat currency was extremely unreliable because its value was based upon the value of the bank it was issued from. In 1836, wildcat currencyhad become so unreliable that Jackson told the Treasury to issue a Specie Circular- a decree that required all public lands to be purchased with metallic money. This drastic step contributed greatly to the financial panic of 1837. The Birth of the Whigs ¢The Whigs were conservatives who supported government programs, reforms, and public schools. They called for internal improvements like canals, railroads, and telegraph lines. ¢The Whigs claimed to be defenders of the common man and declared the Democrats the party of corruption. The Election of 1836 ¢Martin Van Buren was Andrew Jacksons choice as his successor in the election of 1836. General William Henry Harrison was one of the Whigs many presidential nominees. The Whigs did not win because they did not united behind just one candidate. Depression Doldrums and the Independent Treasury ¢The basic cause of the panic of 1837 was the rampant speculation prompted by a get-rich scheme. Gamblers in western lands were doing a land-office business on borrowed capital. The speculative craze spread to canals, roads, railroads, and slaves. Jacksonian finance also helped to cause the panic. In 1836, the failure of two British banks caused the British investors to call in foreign loans. These loans were the beginnings of the panic. ¢The panic of 1837 caused many banks to collapse, commodity prices to drop, sales of public to fall, and the loss of jobs. ¢Van Buren proposed the Divorce Bill. Not passed by Congress, it called for the dividing of the government and banking altogether. ¢The Independent Treasury Bill was passed in 1840. An independent treasury would be established and government funds would be locked in vaults. Gone to Texas ¢Mexico won its independence from Spain in 1823. Mexico gave a huge chunk of land to Stephen Austin who would bring families into Texas. ¢The Texans had many differences with the Mexicans. Mexicans were against slavery, while the Texans supported it. ¢Santa Anna- president of Mexico who, in 1835, wiped out all local rights and started to raise army to suppress the upstart Texans. The Lone Star Rebellion ¢Texas declared its independence in 1836. Sam Houston- commander in chief for Texas. ¢General Houston forced Santa Anna to sign a treaty in 1836 after Houston had captured Santa Anna in the Battle of San Jacinto. ¢The Texans wanted to become a state in the United States but the northerners did not want them to because of the issue of slavery. Admitting Texas would mean one more slave state. Log Cabins and Hard Cider of 1840 ¢William Henry Harrison defeated Van Buren to win the election of 1840 for the Whigs. The Whigs campaign included pictures of log cabins and cider. Politics for the People There were 2 major changes in politics after the Era of Good Feelings: ¢Politicians who were too clean, too well dressed, too grammatical, and too intellectual were not liked. Aristocracy was not liked by the American people. The common man was moving to the center of the national political stage. The Two-Party System: There was a formation of a two-party system. The two parties consisted of the Democrats and the Whigs (the National Republican Party had died out). Jacksonian Democrats glorified the liberty of the individual. They supported states rights and federal restraint in social and economic affairs. The Whigs supported the natural harmony of society and the value of community. They favored a renewed national bank, protective tariffs, internal improvements, public schools, and moral reforms, such as the prohibition of liquor and the abolition of slavery.
Basic Multiplication Tic-Tac-Toe You may need serous Multiplication skills for this game! Adding Signed Numbers Practice adding signed numbers to get the correct sum. Multiplying and Dividing Integers Students will solve problems relating to multiplying and dividing integers in order to progress in the game. Data Table & Graph Review Review Graphing Vocabulary. The last two questions use a graph found here: https://goo.gl/z3K9CA Number Spellings - Large Numbers Choose the correct written number alternative Match the Number Try and match the number to the word Matching Elementary Math Terms Students will match terms to the correct answer. Solve the word problem. Fraction & Decimal Review 4th Fraction & Decimal Review
- History of Boston The history of Boston plays a central role in the American history. In 1630, Puritan colonists from England founded the city, which quickly became the political, commercial, financial, religious, and educational center of the New England region. The American Revolution erupted in Boston, as the British retaliated harshly for the Boston Tea Party and the patriots fought back. They besieged the British in the city, with a famous battle at Bunker Hill and won the Siege of Boston, forcing the British to retreat. However, the British blockade of the port seriously damaged the economy, and the population fell by two thirds in the 1770s. The city recovered after 1800, becoming the transportation hub for the New England region with its network of railroads, and even more important, the intellectual, educational and medical center of the nation. Along with New York, Boston was the financial center of the United States in the 19th century, and was especially important in funding railroads nationwide. In the Civil War era, it was the base for many anti-slavery activities. In the 19th century the city was dominated by an elite known as the Boston Brahmins. They faced the political challenge coming from waves of Catholic immigrants. The Irish Catholics, typified by the Kennedy Family, wrested the political control of the city by 1900. The industrial foundation of the region, financed by Boston, reached its peak around 1950; thereafter thousands of textile mills and other factories were closed down. By the 21st century the city's economy had recovered and was centered on world-famous education, medicine, and high technology—notably biotechnology, while the many surrounding towns became highly attractive residential suburbs. - 1 Prehistoric era - 2 Founding - 3 Colonial era - 4 Boston in rebellion - 5 19th century - 6 20th century - 7 21st century - 8 Geographic expansion - 9 See also - 10 Notes - 11 References - 12 Further reading - 13 External links The Shawmut Peninsula was originally connected to the mainland to its south by a narrow isthmus, Boston Neck, and surrounded by Boston Harbor and the Back Bay, an estuary of the Charles River. Several prehistoric Native American archaeological sites, including the Boylston Street Fishweir, excavated during construction of buildings and subways in the city, have shown that the peninsula was inhabited as early as 7,500 years before present. Trimountaine was the original name given by European settlers to the peninsula that would later be incorporated as the city of Boston. The name was derived from the three prominent hills on the peninsula, two of which were leveled as the city was modernized. The third, Beacon Hill, remains to this day a prominent feature of the Boston cityscape. In 1628, the Cambridge Agreement was signed in England among the Puritans of the Massachusetts Bay Colony. The agreement established the colony as a self-governing entity, answerable only to the king. John Winthrop was its leader, and would become governor of the settlements in the New World. In a famous sermon, "A Model of Christian Charity," Winthrop described the new colony as "a City upon a Hill." In June 1630, the Winthrop Fleet arrived in what would later be called Salem, which on account of lack of food, "pleased them not." They proceeded to Charlestown, which pleased them less, for lack of fresh water. The Puritans settled around the spring in what would become Boston. Governor Winthrop announced the foundation of the City of Boston on September 17, with the place named after the town of Boston, in the English county of Lincolnshire, from which several prominent colonists emigrated. Early colonists believed that Boston was a community with a special covenant with God, as captured in Winthrop's "City upon a Hill" metaphor. This influenced every facet of Boston life, and made it imperative that colonists legislate morality as well as enforce marriage, church attendance, education in the Word of God, and the persecution of sinners. These values molded an extremely stable and well-structured society in Boston. Puritan values of hard work, moral uprightness, and education remain a part of Boston's culture. The first school in America, Boston Latin School (1635), and the first college in America, Harvard College (1636), were founded shortly after Boston's European settlement. Town officials in colonial Boston were chosen annually; positions included selectman, assay master, culler of staves, fence viewer, hayward, hogreeve, measurer of boards, pounder, sealer of leather, tithingman, viewer of bricks, water bailiff, and woodcorder. Boston's Puritans looked askance at unorthodox religious ideas, and exiled or punished dissenters. Baptist minister Obadiah Holmes was imprisoned and publicly whipped in 1651 because of his religion and Henry Dunster, the first president of Harvard College during the 1640s-50s, was persecuted for espousing Baptist beliefs. By 1679, Boston Baptists were bold enough to open their own meetinghouse, which was promptly closed by colonial authorities. Expansion and innovation in practice and worship characterized the early Baptists despite the restrictions on their religious liberty. On June 1, 1660, Mary Dyer was hanged on Boston Common for repeatedly defying a law banning Quakers from proselytizing in the colony. The Boston Post Road connected the city to New York and the major settlements in Central and Western Massachusetts. The lower route ran near present-day U.S. 1 via Providence, Rhode Island. The upper route, laid out in 1673, left via Boston Neck and followed present-day U.S. Route 20 until around Shrewsbury, Massachusetts. It continued through Worcester, Springfield, and New Haven, Connecticut. From 1686 until 1689, Massachusetts and surrounding colonies were united. This larger province, known as the Dominion of New England, was governed by an appointee of the king James II, Sir Edmund Andros. Andros, who supported the Church of England in a largely-Puritan city, grew increasingly unpopular. On April 18, 1689, he was overthrown due to a brief revolt. The Dominion was not reestablished. The first "Great Fire" of Boston destroyed 349 buildings on March 20, 1760. Boston in rebellion By the 1770s Americans focused on their rights as Englishmen, especially the principle of "No Taxation without Representation," as articulated by James Otis, Samuel Adams and other Boston firebrands. Boston played the primary role in sparking both the American Revolution and the ensuing American Revolutionary War. The Boston Massacre came on March 5, 1770, when British soldiers stationed fired into a rioting mob on King Street outside the British custom house, resulting in the deaths of five civilians and dramatically escalating tensions. Parliament, meanwhile, insisted on its right to tax the Americans and finally came up with a small tax on tea. Up and down the 13 colonies, Americans prevented merchants from selling the tea, but a shipment arrived in Boston Harbor. Local Sons of Liberty, disguised as Indians, dumped the tea in the harbor in the Boston Tea Party. The British government retaliated with a series of very harsh laws, they closed down the Port of Boston and stripped Massachusetts of its self-government. The other colonies rallied in solidarity behind Massachusetts, setting up the First Continental Congress, and arming and training their militia units. The British sent more troops to Boston, and made its commander General Thomas Gage the governor. When Gage discovered the Patriots had set up a shadow government based in the town of Concord, he sent troops to break it up. Paul Revere, William Dawes, and Dr. Samuel Prescott made their famous midnight rides to alert the Minutemen in the surrounding towns, who fought the resulting Battle of Lexington and Concord in April 1775. It was the first battle of the American Revolution. Militia units across New England rallied to the defense of Boston, and Congress sent in General George Washington to take command. The British were trapped in the city, and suffered very heavy losses in their victory at the Battle of Bunker Hill; Washington brought in artillery and forced the British out as the patriots took full control of Boston. The American victory on March 17, 1776, is celebrated as Evacuation Day. The city has preserved and celebrated its revolutionary past, from the harboring of the USS Constitution to the many famous sites along the Freedom Trail. Economic and population growth Historical populations Census Pop. %± 1790 18,320 — 1800 24,937 36.1% 1810 33,787 35.5% 1820 43,298 28.1% 1830 61,392 41.8% 1840 93,383 52.1% 1850 136,881 46.6% 1860 177,840 29.9% 1870 250,526 40.9% 1880 362,839 44.8% 1890 448,477 23.6% 1900 560,892 25.1% 1910 670,585 19.6% 1920 748,060 11.6% 1930 781,188 4.4% 1940 770,816 −1.3% 1950 801,444 4.0% 1960 697,197 −13.0% 1970 641,071 −8.1% 1980 562,994 −12.2% 1990 574,283 2.0% 2000 589,141 2.6% Source: Boston was transformed from a relatively small and economically stagnant town in 1780 to a bustling seaport and cosmopolitan center with a large and highly mobile population by 1800. It had become one of the world's wealthiest international trading ports, exporting products like rum, fish, salt and tobacco. The upheaval of the American Revolution, and the British naval blockade that shut down its economy, had caused a majority of the population to flee the city. From a base of 10,000 in 1780, the population approached 25,000 by 1800. The abolition of slavery in the state in 1783 gave blacks greater physical mobility, but their social mobility was slow. Boston had the status of a town; it was chartered as a city in 1822. The second mayor was Josiah Quincy III, who undertook infrastructure improvements in roads and sewers, and organized the city's dock area around the newly erected Faneuil Hall Marketplace, popularly known as Quincy Market. By the mid-19th century Boston was one of the largest manufacturing centers in the nation, noted for its garment production, leather goods, and machinery industries. Manufacturing overtook international trade to dominate the local economy. A network of small rivers bordering the city and connecting it to the surrounding region made for easy shipment of goods and allowed for a proliferation of mills and factories. The building of the Middlesex Canal extended this small river network to the larger Merrimack River and its mills, including the Lowell mills and mills on the Nashua River in New Hampshire. By the 1850s, an even denser network of railroads (see also List of railroad lines in Massachusetts) facilitated the region's industry and commerce. For example, in 1851, Eben Jordan and Benjamin L. Marsh opened the Jordan Marsh Department store in downtown Boston. Thirty years later William Filene opened his own department store across the street, called Filene's. Several turnpikes were constructed between cities to aid transportation, especially of cattle and sheep to markets. A major east-west route, the Worcester Turnpike (now Massachusetts Route 9), was constructed in 1810. Others included the Newburyport Turnpike (now Route 1) and the Salem Lawrence Turnpike (now Route 114). Boston's "Brahmin elite" developed a particular semi-aristocratic value system by the 1840s—cultivated, urbane, and dignified, he was the very essence of enlightened aristocracy. The ideal Brahmin was not only wealthy, but displayed suitable personal virtues and character traits. The term was coined in 1861 by Dr. Oliver Wendell Holmes, Sr. The Brahmin had high expectations to meet: to cultivate the arts, support charities such as hospitals and colleges, and assume the role of community leader. Although the ideal called on him to transcend commonplace business values, in practice many found the thrill of economic success quite attractive. The Brahmins warned each other against "avarice" and insisted upon "personal responsibility." Scandal and divorce were unacceptable. The total system was buttressed by the strong extended family ties present in Boston society. Young men attended the same prep schools and colleges, and had their own way of talking. Heirs married heiresses. Family not only served as an economic asset, but also as a means of moral restraint. Most belonged to the Unitarian or Episcopal churches, although some were Congregationalists or Methodists. Politically, they were successively Federalists, Whigs, and Republicans. A poem about Boston, attributed to various people, describes the city thus: "And here's to good old Boston / The land of the bean and the cod / Where Lowells talk only to Cabots / and Cabots talk only to God." While wealthy colonial families like the Lowells and Cabots (often called the Boston Brahmins) ruled the city, the 1840s brought waves of new immigrants from Europe. These included large numbers of Irish and Italians, giving the city a large Roman Catholic population. In 1831, William Lloyd Garrison founded The Liberator, an abolitionist newsletter, in Boston. It advocated "immediate and complete emancipation of all slaves" in the United States, and established Boston as the center of the abolitionist movement. After the passing of the Fugitive Slave Law of 1850, Boston became a bastion of abolitionist thought. Attempts by slave-catchers to arrest fugitive slaves often proved futile, which included the notable case of Anthony Burns and Kevin McLaughlin. After the passage of the Kansas-Nebraska Act in 1854, Boston also became the hub of efforts to send anti-slavery New Englanders to settle in Kansas Territory through the Massachusetts Emigrant Aid Company. Throughout the 19th century, Boston became a haven for Irish Catholic immigrants, especially following the potato famine of 1845-49. Even to the present day, Boston still commands the largest percentage of Irish-descended people of any city in the United States. Thanks to growing numbers, intense group loyalty, and block by block political organization, the Irish took political control of the city, leaving the Yankees in charge of finance, business and higher education. The Irish left their mark on the region in a number of ways: in still heavily Irish neighborhoods such as Charlestown and South Boston; in the name of the local basketball team, the Boston Celtics; in the dominant Irish-American political family, the Kennedys; in a large number of prominent local politicians, such as James Michael Curley; in the establishment of Catholic Boston College as a rival to Harvard; and in underworld figures such as James "Whitey" Bulger. The Great Boston Fire of 1872 started at the corner of Summer Street and Kingston Street on November 9. In two days the conflagration destroyed about 65 acres (260,000 m²) of the city, including 776 buildings in the financial district, totaling $60 million in damage. From the mid-to-late-19th century, Boston flourished culturally — it became renowned for its rarefied literary culture and lavish artistic patronage. Literary residents included, among many others, writers Nathaniel Hawthorne, Henry Wadsworth Longfellow, Oliver Wendell Holmes, Sr., James Russell Lowell, and Julia Ward Howe, as well as historians John Lothrop Motley, John Gorham Palfrey, George Bancroft, William Hickling Prescott, Francis Parkman, Henry Adams, James Ford Rhodes, Edward Channing and Samuel Eliot Morison. Also there were theologians and philosophers such as William Ellery Channing, Ralph Waldo Emerson and Mary Baker Eddy. When Bret Harte visited Howells, he remarked that in Boston "it was impossible to fire a revolver without bringing down the author of a two-volume work." Boston had many great publishers and magazines, such as The Atlantic Monthly (founded 1857) and the publishers Little, Brown and Company, Houghton Mifflin, and Harvard University Press. Higher education became increasingly important, not only at Harvard (based across the river in Cambridge) but at other institutions. The Massachusetts Institute of Technology (MIT) opened in the city in 1865. The first medical school for women, The Boston Female Medical School (which later merged with the Boston University School of Medicine), opened in Boston on November 1, 1848. The Jesuits opened Boston College in 1863; Emerson College opened in 1880, and Simmons College for women in 1899. To please a different audience, the first vaudeville theater opened on February 28, 1883, in Boston. The last one, the Old Howard in Scollay Square, which had evolved from opera to vaudeville to burlesque, closed in 1953. As the population increased rapidly, Boston-area streetcar lines facilitated the creation of a profusion of streetcar suburbs. Downtown congestion worsened, prompting the opening of the first subway in North America on September 1, 1897, the Tremont Street Subway. Between 1897 and 1912, subterranean rail links were built to Cambridge and East Boston, and elevated and underground lines expanded into other neighborhoods from downtown. Today, the regional passenger rail and bus network has been consolidated into the Massachusetts Bay Transportation Authority. Two union stations, North Station and South Station were constructed to consolidate downtown railroad terminals. From the late 19th century until the mid-20th century, the phrase "Banned in Boston" was used to describe a literary work, motion picture, or play prohibited from distribution or exhibition. During this time, Boston city officials took it upon themselves to "ban" anything that they found to be salacious, immoral, or offensive: theatrical shows were run out of town, books confiscated, and motion pictures were prevented from being shown—sometimes stopped in mid-showing after an official had "seen enough". The phrase "banned in Boston" came to suggest something sexy and lurid; some distributors advertised that their products had been banned in Boston, when in fact they had not. In 1900 Julia Harrington Duff (1850–1932) became the first woman from the Irish Catholic community to be elected to the Boston School Committee. Extending her role as teacher and mother she became an ethnic spokesperson as she confronted the power of the Yankee Protestant men of the Public School Association. She worked to replace 37-year-old textbooks, to protect the claims of local Boston women for career opportunities in the school system, and to propose a degree-granting teachers college. In 1905, the 25 member committee was reduced to five, which blocked women's opportunities for direct participation in school policies. On January 15, 1919, the Boston Molasses Disaster occurred in the North End. Twenty-one people were killed and 150 injured as an immense wave of molasses crushed and asphyxiated many of the victims to death. It took over six months to remove the molasses from the cobblestone streets, theaters, businesses, automobiles, and homes. Boston Harbor ran brown until summer. During the summer of 1919, over 1100 members of the Boston Police Department went on strike. Boston fell prey to several riots as there were minimal law officers to maintain order in the city. Calvin Coolidge, then governor of Massachusetts, garnered national fame for quelling violence by almost entirely replacing the police force. The 1919 Boston Police Strike would ultimately set precedent for police unionization across the country. On August 23, 1927, Italian anarchists Nicola Sacco and Bartolomeo Vanzetti were sent to the electric chair after a seven-year trial in Boston. Their execution sparked riots in London, Paris and Germany, and helped to reinforce the image of Boston as a hotbed of intolerance and discipline. Transportation and urban renewal The I-695 Inner Belt shown on this map was never built. I-95 is shown here approaching the urban core from the southwest, but it was never built beyond the outer loop shown on this map (which was built as Route 128 and which I-95 was later re-routed over). By 1950, Boston was slumping. Few major buildings were being built anywhere in the city. Factories were closing and moving their operations south, where labor was cheaper. The assets Boston had—excellent banks, hospitals, universities and technical know-how—were minimal parts of the U.S. economy. To combat this downturn, Boston's politicians enacted urban renewal policies, which resulted in the demolition of several neighborhoods, including the old West End, a largely Jewish and Italian neighborhood, and Scollay Square. In their places went the Charles River Park apartment complex, additions to Massachusetts General Hospital, and Government Center. These projects displaced thousands, closed hundreds of businesses, and provoked a furious backlash, which in turn ensured the survival of many historic neighborhoods. In 1948, William F. Callahan had published the Master Highway Plan for Metropolitan Boston. Parts of the financial district, Chinatown, and the North End were demolished to make way for construction. By 1956, the northern part of the Central Artery had been constructed, but strong local opposition resulted in the southern downtown portion being built underground. The Dewey Square Tunnel connected downtown to the Southeast Expressway. In 1961, the Callahan Tunnel opened, paralleling the older Sumner Tunnel. By 1965, the first Massachusetts Turnpike Extension was completed from Route 128 to near South Station. The proposed Inner Belt in Boston, Cambridge, Brookline, and Somerville was canceled due to public outcry. In 1971, public protest canceled the routing of I-95 into downtown Boston. Demolition had already begun along the Southwest Corridor, which was instead used to re-route the Orange Line and Amtrak's Northeast Corridor. In 2007, the Central Artery/Tunnel project was completed. Nicknamed the Big Dig, it had been planned and approved in the 1980s under Massachusetts governor Michael Dukakis. With construction beginning in 1991, the Big Dig moved the remainder of the Central Artery underground, widened the north-south highway, and created local bypasses to prevent east-west traffic from contributing to congestion. The Ted Williams Tunnel became the third highway tunnel to East Boston and Logan International Airport as part of the project. The Big Dig also produced the landmark Zakim Bunker Hill Bridge, and will create over 70 acres (280,000 m²) of public parks in the heart of the city. The project as a whole has eased (but not eliminated) Boston's notorious traffic congestion; however, it is the most expensive construction project in United States history and the most expensive construction project in the world. The city also saw other transportation projects, including improvement and expansion to its mass transit system, notably to its commuter rail system to southeastern Massachusetts and the development of a bus rapid transit (BRT) system dubbed "The Silver Line." The maritime Port of Boston and Logan International Airport were also developed. World War II and later During the war years, antisemitic violence escalated in Boston. Gangs largely composed of Irish Catholic youths desecrated Jewish cemeteries and synagogues, vandalized Jewish stores and homes, and physically assaulted Jews in the streets. The Boston police force, which was made up largely of Irish Catholics, seldom intervened. In 1953, the Columbia Point public housing projects were completed on the Dorchester peninsula. There were 1,502 units in the development on 50 acres (200,000 m2) of land. In 1966, the Columbia Point Health Center opened and was the first community health center in the country. Between June 14, 1962, and January 4, 1964, as many as thirteen single women between the ages of 19 and 85 were murdered in Boston by the infamous Boston Strangler. (The actual number remains in dispute.) In the 1970s, after years of economic downturn, Boston boomed again. Financial institutions were granted more latitude, more people began to play the market, and Boston became a leader in the mutual fund industry. Health care became more extensive and expensive, and hospitals such as Massachusetts General Hospital, Beth Israel Deaconess Medical Center, and Brigham and Women's Hospital led the nation in medical innovation and patient care. Higher education also became more expensive, and universities such as Harvard, MIT, BU and Tufts attracted hordes of students to the Boston area; many stayed and became permanent residents. MIT graduates, in particular, founded many successful high-tech companies, which made Boston second only to Silicon Valley as a high-tech center. In 1974, the city dealt with a crisis when a federal district court judge, W. Arthur Garrity, ordered desegregation busing to integrate the city's public schools. Racially-motivated violence erupted in several neighborhoods (many white parents resisted the busing plan). Public schools—particularly public high schools—became scenes of unrest and violence. Tension continued throughout the mid-1970s, reinforcing Boston's reputation for discrimination. The Columbia Point housing complex deteriorated until only 350 families remained living there in 1988. In 1984, the city of Boston gave control of the complex to a private developer, Corcoran-Mullins-Jennison, who re-developed and re-vitalised the property into a residential mixed-income community called Harbor Point Apartments. It is a very significant example of revitalisation and re-development and was the first federal housing project to be converted to private, mixed-income housing in the USA. Harbor Point has won much acclaim for this transformation, including awards from the Urban Land Institute, the FIABCI Award for International Excellence, and the Rudy Bruner Award. It was used as a model for the federal HUD HOPE VI public housing program begun in 1992. On March 18, 1990, the largest art theft in modern history occurred in Boston. Twelve paintings, collectively worth over $100 million, were stolen from the Isabella Stewart Gardner Museum by two thieves posing as police officers. As of 2010 these paintings have not been recovered. Recently, Boston has experienced a loss of regional institutions and traditions, which once gave it a very distinct social character, as it has become part of the northeastern megalopolis. Examples include: the acquisition of the Boston Globe by The New York Times; the loss of Boston-headquartered publishing houses (noted above); the acquisition of the century-old Jordan Marsh department store by Macy's; the increasing rarity of ice-cream shops using cone-shaped scoops; and the loss to mergers, failures, and acquisitions of once-prominent financial institutions such as Shawmut Bank, BayBank, Bank of New England, and Bank of Boston. In 2004, this trend continued as Charlotte-based Bank of America acquired FleetBoston Financial, and P&G has announced plans to acquire Gillette. Despite these losses, Boston's ambiance remains unique among world cities and, in many ways, has improved in recent years—racial tensions have eased dramatically, city streets bustle with a vitality not seen since the 1920s, and once again Boston has become a hub of intellectual, technological, and political ideas. Nevertheless, the city had to tackle gentrification issues and rising living expenses. According to Money Magazine, Boston is one of the world's 100 most expensive cities. Boston was the host city of the 2004 Democratic National Convention. The city also found itself at the center of national attention in early 2004 during the controversy over same-sex marriages. After the Massachusetts Supreme Judicial Court ruled that such marriages cannot be banned under the state's constitution, opponents and supporters of such marriages converged on the Massachusetts State House as the state legislature voted on a state constitutional amendment that would define marriage as only between a man and a woman. Much attention was focused on the city and the rest of Massachusetts when marriage licenses for same-sex couples were issued. The City of Boston has expanded in two ways - through landfill and through annexation of neighboring municipalities. Between 1630 and 1890, the city tripled its physical size by land reclamation, specifically by filling in marshes and mud flats and by filling gaps between wharves along the waterfront, a process Walter Muir Whitehill called "cutting down the hills to fill the coves." The most intense reclamation efforts were in the 19th century. Beginning in 1807, the crown of Beacon Hill was used to fill in a 50-acre (20 ha) mill pond that later became the Bulfinch Triangle (just south of today's North Station area). The present-day State House sits atop this shortened Beacon Hill. Reclamation projects in the middle of the century created significant parts of the areas now known as the South End, West End, Financial District, and Chinatown. After The Great Boston Fire of 1872, building rubble was used as landfill along the downtown waterfront. The most dramatic reclamation project was the filling in of the Back Bay in the mid to late 19th century. Almost six hundred acres (240 hectares) of brackish Charles River marshlands west of the Boston Common were filled in with gravel brought in by rail from the hills of Needham Heights. Boston also grew by annexing the adjacent communities of East Boston, Roxbury, Dorchester, West Roxbury (including Jamaica Plain and Roslindale), South Boston, Brighton, Allston, Hyde Park, and Charlestown, some of which were also augmented by landfill reclamation. Timeline of annexations, secessions, and related developments (incomplete): - 1705 - Hamlet of Muddy River split off to incorporate as Brookline - 1804 - First part of Dorchester by act of the state legislature - 1851 - West Roxbury (including Jamaica Plain and Roslindale) is split off from Roxbury as an independent municipality. - 1855 - Washington Village, part of South Boston, by act of the state legislature - 1868 - Roxbury - 1870 - Last part of Dorchester - 1873 - Brookline-Boston annexation debate of 1873 (Brookline was not annexed) - 1874 - West Roxbury, including Jamaica Plain and Roslindale (approved by voters in 1873) - 1874 - Town of Brighton (including Allston) (approved by voters in 1873) - 1874 - Charlestown (approved by voters in 1873) - 1912 - Hyde Park - 1986 - Vote to create Mandela from parts of Roxbury, Dorchester, and the South End passes locally but fails city-wide. Timeline of land reclamation (incomplete): - 1857 - Filling of the Back Bay begins - 1882 - Present-day Back Bay fill complete - 1890 - Charles River landfill reaches Kenmore Square, formerly the western end of the Back Bay mill pond - 1900 - Back Bay Fens fill complete - Timeline of Boston history - List of newspapers in Massachusetts in the 18th-century: Boston - Timeline of Boston history - ^ "Archaeology of the Central Artery Project: Highway to the Past". Commonwealth Museum – Massachusetts Historical Commission. 2007. http://www.sec.state.ma.us/mhc/mhcexh/exhidx.htm. Retrieved 2007-04-06. - ^ "Boston Charter Day". Bostoncharterday.org. 2007. http://www.bostoncharterday.org/. Retrieved 2008-09-25. - ^ "World Chronology - 1630". Answers.com. 2007. http://www.answers.com/topic/1630. - ^ Weston, George F. Boston Ways: High, By & Folk, Beacon Press: Beacon Hill, Boston, p.11-15 (1957). - ^ Weston, George F., - ^ Robert Francis Seybolt. The Town Officials of Colonial Boston, 1634–1775. Cambridge, Mass.: Harvard University Press, 1939 - ^ Hogreeve: "chiefly in New England and south-eastern Canada: a person appointed to impound stray pigs, and to prevent or assess any damage caused by them;" cf. Oxford English Dictionary, 3rd ed. 2010 - ^ Pounder: "a person whose occupation it is to pound cattle or other livestock;" cf. Oxford English Dictionary, 3rd ed. 2010 - ^ Woodcorder: "a town official responsible for stacking cut wood for sale into standard ‘cords’ piles;" cf. Oxford English Dictionary, 3rd ed. 2010 - ^ Milton P. Ryder, "Swimming Against the Current: The Strange Therapy of Persecution; The Price Paid for Religious Liberty by Some Early Massachusetts Baptists and the First Baptist Church of Boston," American Baptist Quarterly, March 2002, Vol. 21 Issue 1, pp 11-27 - ^ The Massachusetts Historical Society. The Cape Ann Earthquake of November 1755 By John E. Ebel, Ph.D. Professor of Geophysics, Boston College - ^ USGS Historic Earthquakes - ^ Hiller B. Zobel, The Boston Massacre (1970) - ^ "Annual Estimates of the Resident Population for Incorporated Places Over 100,000, Ranked by July 1, 2009 Population: April 1, 2000 to July 1, 2009". U.S. Census Bureau. http://www.census.gov/popest/cities/tables/SUB-EST2009-01.csv. - ^ University Archives Colonial Boston - ^ Jacqueline Barbara Carr, "A Change 'as Remarkable as the Revolution Itself': Boston's Demographics, 1780-1800," New England Quarterly, Dec 2000, Vol. 73 Issue 4, pp 583-602 - ^ US History.com, Cities, Boston, Massachusetts - ^ Ronald Story, Harvard and the Boston Upper Class: The Forging of an Aristocracy, 1800-1970 (1985). - ^ Paul Goodman, "Ethics and Enterprise: The Values of a Boston Elite, 1800-1860," American Quarterly, Sept 1966, Vol. 18 Issue 3, pp 437-451 - ^ Holmes entitled the first chapter of his 1861 novel Elsie Venner "The Brahmin caste of New England"; he had long been writing about the group without using the term "Brahmin." - ^ Ronald Story, "Harvard Students, The Boston Elite, And The New England Preparatory System, 1800-1870," History of Education Quarterly, Fall 1975, Vol. 15 Issue 3, pp 281-298 - ^ Van Wyck Brooks, The flowering of New England (1955) - ^ Polly Welts Kaufman, "Julia Harrington Duff: An Irish Woman Confronts the Boston Power Structure, 1900-1905," Historical Journal of Massachusetts, 1990 18(2): 113-137, 25p. Historic - ^ Stanleysteameronline.com - ^ Clymer, Floyd. Treasury of Early American Automobiles, 1877-1925 (New York: Bonanza Books, 1950), p.13. - ^ Vale, Lawrence J., From the Puritans to the projects: public housing and public neighbors, Harvard University Press, 2000. - ^ Susan Moir (University of Massachusetts Lowell). "Big Dig". Electronic Library of Construction - Occupational Safety and Health (CDC). http://www.elcosh.org/docs/d0100/d000067/d000067.html. - ^ Norwood, Stephen H. (2003). "Marauding Youth and the Christian Front: Antisemitic Violence in Boston and New York during World War II". American Jewish History 91. - ^ Kamin, Blair. "Rethinking Public Housing", Blueprints magazine, Summer 1997, p.4, National Building Museum, Washington, D.C. - ^ Roessner, Jane. "A Decent Place to Live: From Columbia Point to Harbor Point", Boston, Northeastern University Press, 2000. - ^ "Boston War Zone Becomes Public Housing Dream", The New York Times, November 23, 1991. - ^ Cf. Roessner, p.293. "The HOPE VI housing program, inspired in part by the success of Harbor Point, was created by legislation passed by Congress in 1992." - ^ "World's most expensive cities." Money Magazine. Accessed June 30, 2005. - ^ a b c d e "New Boston and the Suburbs". Kellscraft Studio. 1999-2003. http://www.kellscraft.com/bostonillustrated/bostonillustrated07.html. - ^ Lewis, Geoff; Avault, John; Vrabel, Jim (November 1999) (PDF), History of Boston's Economy, Growth and Transition 1970 - 1998, Boston, Massachusetts: Boston Redevelopment Authority, pp. 31, http://www.cityofboston.gov/bra/PDF/ResearchPublications//pdr529.pdf - Winsor, Justin (1881). Memorial History of Boston, Vol.1 [http://books.google.com/books?id=U0AOAAAAIAAJ&printsec=frontcover&dq=intitle:Memorial+intitle:History+intitle:of+intitle:Boston&num=50&cad=3_1 Vol.2 Vol.3. Vol.4.]. James R. Osgood Publisher.. http://books.google.com/books?id=1z8OAAAAIAAJ&printsec=frontcover&dq=editions:0jkSXQveT0SxV7GZV0DYhMn#PPR3,M1. - Snow, Caleb H. (1828). History of Boston. Abel Bowen. http://books.google.com/books?id=7eovZyvw7S8C&pg=PA9&dq=editions:0tsIsk90aiMeVh&cad=0_0#PPP13,M1. - Boston (1909). Records Relating to the Early History of Boston - Selectmen Minutes 1818-1822.. City of Boston. http://books.google.com/books?id=olMMAAAAYAAJ&pg=PA98&dq=intitle:History+intitle:of+intitle:Boston&num=50#PPP5,M1. - Downst, Henry P. (1916). Random Notes of Boston. Humphrey Publishing. http://kellscraft.com/NotesBoston/NotesBostoncontentpage.html. - Bacon, Edwin M. (1886). Boston Illustrated. http://www.kellscraft.com/bostonillustrated/bostonillustratedcontent.html. - Cole, William I. (April 1898). "Boston's Pauper Institutions". The New England Magazine 24 (2). http://cdl.library.cornell.edu/cgi-bin/moa/moa-cgi?notisid=AFJ3026-0024-33. - Patricia Harris and David Lyon (1999). Boston. Oakland, California: Compass American Guides. ISBN 0-679-00284-7. - Howard Mumford Jones and Bessie Zaban Jones (1975). The Many Voices of Boston: A Historical Anthology 1630-1975. Boston: Little, Brown and Company. ISBN 0-316-47282-4. - Langford, Jane Ellen (September 26, 1997). "Colonial Boston Unearthed". Archaeology, Archaeological Institute of America. http://www.archaeology.org/online/features/boston/. - Seasholes, Nancy S. (2003). Gaining ground : a history of landmaking in Boston. Cambridge, Massachusetts: MIT Press. http://books.google.com/books?id=GAHs1C9q1EsC&printsec=frontcover. - Shackleton, Robert (1916). The Book of Boston. http://www.kellscraft.com/BookofBoston/BookofBostoncontentpage.html. - Winsor, Justin, Jewett, C.F. (1880). The Memorial History of Boston Including Suffolk County, Massachusetts. 1630-1880. http://www.helloboston.com/80_LocalBook.Cfm. - Historical 1842 map of Boston - "Boston" from Tanner, H.S. The American Traveller; or Guide Through the United States. Eighth Edition. New York, 1842. - Dutton, E.P. Chart of Boston Harbor and Massachusetts Bay with Map of Adjacent Country. Published 1867. A good map of roads and rail lines in and around Boston. - Bacon, Edwin Monroe. The Book of Boston: Fifty Years' Recollections of the New England Metropolis. Published 1916, 534 pages. - Beatty, Jack. The Rascal King: The Life and Times of James Michael Curley, 1874-1958 (1992) online edition - Blake, John B. Public Health in the Town of Boston, 1630-1822 (Harvard UP, 1959). - Carp, Benjamin L. Defiance of the Patriots: The Boston Tea Party and the Making of America (2010) - Fischer, David Hackett. Paul Revere's Ride (Oxford UP, 19940 online edition - Formisano, Ronald P., Constance K. Burns, eds. Boston, 1700-1980: The Evolution of Urban Politics (Greenwood Press, 1984) online edition, the standard political history - Handlin, Oscar. Boston's Immigrants: A Study in Acculturation (1941) - Kane, Paula M. Separatism and Subculture: Boston Catholicism, 1900-1920 (2001) online edition - McCaughey, Robert A. Josiah Quincy 1772-1864: The Last Federalist (Harvard UP, 1974) - Miller, John C. Sam Adams, Pioneer in Propaganda (1936) - O'Connor, Thomas H. The Boston Irish: A Political History (2007) - Russell, Francis. A City in Terror--1919--: The Boston Police Strike (1975). - Rutman, Darrett B. Winthrop's Boston: Portrait of a Puritan Town, 1630-1649 (U of North Carolina Press, 1965). - Sammarco, Anthony Mitchell; Price, Michael, Boston's immigrants, 1840-1925, Arcadia Publishing, Images of America series, 2000 - Sammarco, Anthony Mitchell, Boston: A Century of Progress, Arcadia Publishing, Images of America series, 1995 - Sammarco, Anthony Mitchell, The Great Boston Fire of 1872, Arcadia Publishing, Images of America series, 1997 - Ulrich, Laurel Thatcher, Big Dig, Little Dig, Hidden Worlds: Boston, Common-Place, American Antiquarian Society, v.3, n.4, July 2003 - Vale, Lawrence J., "From the Puritans to the Projects: Public Housing and Public Neighbors" (Cambridge, Mass.: Harvard Press, 2000). - Warden, Gerard B. Boston, 1689-1776 (1970), the standard history for the period - Waters, John J. The Otis Family in Provincial and Revolutionary Massachusetts (1968) - Whitehill, Walter Muir. Boston: A Topographical History, (2nd ed. Harvard UP, 1968), on geography and neighborhoods - Bacon, Edwin Munroe, and Edward, George, "Ellis Bacon's Dictionary of Boston", Houghton, Mifflin and company, 1886. - Hartnell, Edward Mussey; McGlenen, Edward Webster; Skelton, Edward Oliver, Boston and its story, 1630-1915, City of Boston (Mass.), Printing Department, 1916. - King, Moses, King's hand-book of Boston', Cambridge, Mass., M. King, 1878 - Quincy, Josiah, A Municipal History of the Town and City of Boston During Two Centuries from September 17, 1630 to September 17, 1830, Boston : Charles C. Little & James Brown, 1852. - Snow, Caleb Hopkins, A History of Boston : The Metropolis of Massachusetts, Boston : Abel Bowen, 1828 - Winsor, Justin. ed. The Memorial History of Boston (4 vols. 1880-81), unusually rich details vol 1 online; vol 2 online - The Boston Historical Society - City of Boston Archaeology Program and Lab - The City of Boston has a City Archaeologist on staff to oversee any lots of land to be developed for historical artifacts and significance, and to manage the archaeological remains located on public land in Boston, and also has a City Archaeology Program and an Archaeology Laboratory, Education and Curation Center. - The Freedom House Photographs collection contains over 2,000 images of Roxbury people, places and events, 1950-1975 (Archives and Special Collections of the Northeastern University Libraries in Boston, MA). - Vital Records of Boston. - Reading and Everyday Life in Antebellum Boston: The Diary of Daniel F. and Mary D.Child Culture & economy Lists & related Wikimedia Foundation. 2010. Look at other dictionaries: History of Boston, Massachusetts — The history of Boston, Massachusetts, intertwines with the history of the United States. Boston is the capital of the Commonwealth of Massachusetts, and the historical center of New England.The first Euro American settlement in the immediate area … Wikipedia Boston University — Seal of Boston University Latin: Universitas Bostoniensis Motto Learning, Virtue, Piety[ … Wikipedia Boston — Saltar a navegación, búsqueda Para otros usos de este término, véase Boston (desambiguación). City of Boston Boston … Wikipedia Español Boston University School of Theology — (BUSTH) is the oldest theological seminary of American Methodism and the founding school of Boston University, the largest private research university in New England. It is one of thirteen theological schools maintained by the United Methodist… … Wikipedia Boston Brahmin — Boston Brahmins are wealthy Yankee families characterized by a highly discreet and inconspicuous life style. Based in and around Boston, they form an integral part of the historic core of the East Coast establishment. They are associated with the … Wikipedia Boston Custom House — Boston Custom House, early 19th c. The Custom House in Boston, Massachusetts, was established in the 17th century and stood near the waterfront in several successive locations through the years. In 1849 the U.S. federal government constructed a… … Wikipedia Boston (Massachusetts) — Boston Spitzname: Beantown, The Hub of the Universe, The Cradle of Liberty, City on a Hill, Athens of America Skyline von Boston … Deutsch Wikipedia Boston — Spitzname: Beantown, The Hub of the Universe, The Cradle of Liberty, City on a Hill, Athens of America Skyline von Boston … Deutsch Wikipedia Boston By Foot — is a non profit organization offering guided architectural and historical tours of Boston, Massachusetts. Founded in 1976, Boston By Foot offers daily scheduled tours from May through October. [cite news… … Wikipedia BOSTON — BOSTON, capital and principal city of Massachusetts. The Jewish population of Greater Boston was estimated at 254,000 (2000). Early History Though Boston is one of the oldest cities in North America, having been first settled in 1628, it was not… … Encyclopedia of Judaism
The enigmatic fingerprints of gamma-ray bursts Space Science News home The mysterious fingerprints of gamma-ray bursts "Hard" and "soft" colors put gamma-ray bursts in a different light gamma-ray bursts in a different light Right: The "color-color" diagram at right links to athat depicts the evolution of the burst's hard:soft ratio. What's in a name? Bursts are designated by when they occur (two digits for year, month, date) instead of the location designator normally used for stars. So, this burst was observed May 3, 1991. (Tim Giblin, UAH & NASA) Gamma-ray bursts mystified scientists since they were discovered in the late 1960s by military satellites monitoring a nuclear test ban treaty. At first they debated whether the bursts were from within or near our galaxy - or far away. Observations by the Burst and Transient Source Experiment (BATSE), launched in April 1991, helped establish that most bursts come from cosmological distances - billions of light years from Earth. That discovery directed scientists to another mystery: What could cause so bright a blast at so great a distance? The answer is yet to be found, but scientists at NASA's Marshall Space Flight Center may have developed a way to lift spectral "fingerprints" that may help find the culprit. Left: The Compton Gamma Ray Observatory is deployed by the Space Shuttle in April 1991. Four of the eight BATSE instruments can be seen at the spacecraft's corners. The other four are on the opposite face. (NASA) Giblin will outline his study today at the American Astronautical Society's annual conference in Austin, Texas. "I'm trying to identify classes of bursts - if they exist - by examining their spectral properties over time," Giblin said, "and to look for spectral behavior that we have not seen before." Scientists have found no clear classification scheme for gamma-ray bursts. If one can be found, it would help in directing studies to determine an even bigger mystery, What causes bursts? In his quest, Giblin is applying the four energy channels or "colors" that BATSE can see in the "Color-Color Diagram" method used in other branches of astrophysics. BATSE does more than simply detect a burst. Among its many capabilities, BATSE measures a burst's intensity every 64 milliseconds (about 156 times a second) in four energy channels: 25-50 keV, 50-100 keV, 100-300 keV, and 300-2,000 keV (or, 2 MeV). Visible light, by comparison, is centered around 3 eV. Often, a burst fades fastest in the highest energy output than in its lower energy output. Giblin and his colleagues at NASA/Marshall had suspected that there was more to it than simply flaring and fading. Sign up for our EXPRESS SCIENCE NEWS delivery Gamma Ray Bursts NEWS & RESEARCH American Astronomical Society 193rd meeting program. Gamma-ray Bursters cross the 'Line of Death' - Oct. 13, 1998. A study of gamma ray burst spectra shows one more thing that these mysterious, cosmological gamma ray bursts are not. Blast from the past: the latest clue in solving the gamma-ray burst mystery (May 6, 1998). Gamma-ray burst identification earns top prize (Jan. 12, 1998) Discovery may be "smoking gun" in gamma-ray mystery (March 31, 1997). Twinkle, twinkle, massive fireball - reports from the 4th Huntsville Gamma-ray Burst Symposium (Sept. 17, 1997) Giblin compared a burst's brightness at different energies - the ratios of channel 2 to 1, and of channel 4 to 3 - as the burst evolved with time. It's like striking a match and comparing its green-vs.-red brightness (the "soft" color ratio) against its ultraviolet-vs.-blue brightness (the "hard" color ratio). In a sense, Giblin is measuring how "red" or "blue" the bursts are at different times in their histories. This "color-color" diagram is plotted in colors that indicate the progression of the burst through time, from blue at the start of the flash to green at midpoint to red at the end. This makes it easier for the eye to track the burst's progress in time. What Giblin found was that the 50 brightest gamma ray bursts formed several distinctive patterns. The most common, occurring in 36 percent, is a crescent. The second largest group (18 percent) formed islands and flats ("blobs," Giblin said.). Other groups are a loop (10 percent), an ear with a lobe (7 percent), and a bar (9 percent). About 21 percent formed no discernible pattern. Five distinct patterns have emerged for color-color diagrams of gamma-ray bursts. Links to. (Tim Giblin, UAH & NASA) In some cases, the crescent pattern actually is a double crescent, Giblin explained. As the burst declines, it more or less doubles back on the trace it left as it rose. Others, such as the lobe, indicate that the burst's color is "harder" - it is stronger at the higher energies - at its start than during its finish. Looking at the bursts in greater detail reveals that some crescents trace a sawtooth pattern inherent to the highly variable nature of the burst. Just what the different patterns mean in terms of the burst source remains to be seen. Giblin is running computer simulations that include evolution of the spectral model and to look at the time profiles in an artificial pulse. Giblin found that different pulse shapes produce different patterns in the color-color diagram. "Gamma ray bursts are really made of a series of pulses, each having its own spectral behavior," Giblin said. "I think this trace is telling us that these events are more complex than we thought." More Space Science Headlines - NASA research on the web NASA's Office of Space Science press releases and other news related to NASA and astrophysics sign up for our express news delivery and you will receive a mail message every time we post a new story!!!
"This melt-rich layer is actually quite spotty under the Pacific Ocean basin and surrounding areas, as revealed by my analysis of seismometer data," says Dr. Nicholas Schmerr, a NASA Postdoctoral Program fellow. "Since it only exists in certain places, it can't be the only reason why rigid crustal plates carrying the continents can slide over softer rock below." Schmerr, who is stationed at NASA's Goddard Space Flight Center in Greenbelt, Md., is author of a paper on this research appearing in Science on March 23. The slow slide of Earth's continents results from plate tectonics. Our planet is more than four billion years old, and over this time, the forces of plate tectonics have carried continents many thousands of miles, forging mountain ranges when they collided and valleys that sometimes filled with oceans when they were torn apart. This continental drift could also have changed the climate by redirecting currents in the ocean and atmosphere. The outermost layer of Earth, the lithosphere, is broken into numerous tectonic plates. The lithosphere consists of the crust and an underlying layer of cool and rigid mantle. Beneath the oceans, the lithosphere is relatively thin (about 65 miles), though beneath continents, it can be as thick as 200 miles. Lying beneath the lithosphere is the asthenosphere, a layer of rock that is slowly deforming and gradually flowing like taffy. Heat in Earth's core produced by the radioactive decay of elements escapes and warms mantle rocks above, making them softer and less viscous, and also causes them to convect. Like the circulating blobs in a lava lamp, rock in the mantle rises where it is warmer than its surroundings, and sinks where it's cooler. This churn moves the continental plates above, similar to the way a raft of froth gets pushed around the surface of a simmering pot of soup. Although the basic process that drives plate tectonics is understood, many details remain a mystery. "Something has to decouple the crustal plates from the asthenosphere so they can slide over it," says Schmerr. "Numerous theories have been proposed, and one of those was that a melt-rich layer lubricates the boundary between the lithosphere and the asthenosphere, allowing the crustal plates to slide. However, since this layer is only present in certain regions under the Pacific plate, it can't be the only mechanism that allows plate tectonics to happen there. Something else must be letting the plate slide in areas where the melt doesn't exist." Other possible mechanisms that would make the boundary between the lithosphere and the asthenosphere flow more easily include the addition of volatile material like water to the rock and differences in composition, temperature, or the grain size of minerals in this region. However, current data lacks the resolution to distinguish among them. Schmerr made the discovery by analyzing the arrival times of earthquake waves at seismometers around the globe. Earthquakes generate various kinds of waves; one type has a back-and-forth motion and is called a shear wave, or S-wave. S-waves traveling through the Earth will bounce or reflect off material interfaces inside the Earth, arriving at different times depending on where they interact with these interfaces. One type of S-wave reflects from Earth's surface halfway between an earthquake and a seismometer. An S-wave encountering a deeper melt layer at the lithosphere-asthenosphere boundary at this location will take a slightly shorter path to the seismometer and therefore arrive several tens of seconds earlier. By comparing the arrival times, heights, and shapes of the primary and the melt-layer-reflected waves at various locations, Schmerr could estimate the depth and seismic properties of melt layers under the Pacific Ocean basin. "Most of the melt layers are where you would expect to find them, like under volcanic regions like Hawaii and various active undersea volcanoes, or around subduction zones – areas at the edge of a continental plate where the oceanic plate is sinking into the deep interior and producing melt," said Schmerr. "However, the interesting result is that this layer does not exist everywhere, suggesting something other than melt is needed to explain the properties of the asthenosphere." Understanding how plate tectonics works on Earth could help us figure out how other rocky planets evolved, according to Schmerr. For example, Venus has no oceans, and no evidence of plate tectonics, either. This might be a clue that water is needed for plate tectonics to work. One theory proposes that without water, the asthenosphere of Venus will be more rigid and unable to sustain plates, suggesting internal heat is released in some other way, maybe through periodic eruptions of global volcanism. Schmerr plans to analyze data from other seismometer networks to see if the same patchy pattern of melt layers exists under other oceans and the continents as well. The research was supported by the NASA Postdoctoral Program and the Carnegie Institution of Washington Department of Terrestrial Magnetism Postdoctoral Fellowship.For a related image, refer to: Bill Steigerwald \| EurekAlert! New Measurement Device: Carbon Dioxide As Geothermometer 21.05.2019 \| Universität Heidelberg Cause for variability in Arctic sea ice clarified 14.05.2019 \| Max-Planck-Institut für Meteorologie Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a... With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time. Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists... 'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing. However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been... Working group led by physicist Professor Ulrich Nowak at the University of Konstanz, in collaboration with a team of physicists from Johannes Gutenberg University Mainz, demonstrates how skyrmions can be used for the computer concepts of the future When it comes to performing a calculation destined to arrive at an exact result, humans are hopelessly inferior to the computer. In other areas, humans are... Scientists develop a molecular recording tool that enables in vivo lineage tracing of embryonic cells The beginning of new life starts with a fascinating process: A single cell gives rise to progenitor cells that eventually differentiate into the three germ... 29.04.2019 \| Event News 17.04.2019 \| Event News 15.04.2019 \| Event News 21.05.2019 \| Materials Sciences 21.05.2019 \| Materials Sciences 21.05.2019 \| Life Sciences
A network packet is a formatted unit of data carried by a packet-switched network. A packet consists of control information and user data, known as the payload. Control information provides data for delivering the payload, for example: source and destination network addresses, error detection codes, sequencing information. Control information is found in packet headers and trailers. In packet switching, the bandwidth of the communication medium is shared between multiple communication sessions, in contrast to circuit switching, in which circuits are preallocated for the duration of one session and data is transmitted as a continuous bit stream. In the seven-layer OSI model of computer networking, packet refers to a protocol data unit at layer 3, the network layer; the correct term for a data unit at layer 2, the data link layer, is a frame, at Layer 4, the transport layer, the correct term is segment or datagram. For TCP/IP communication over Ethernet, a TCP segment is carried in one or more IP packets, which are each carried in one or more Ethernet frames. The basis of the packet concept is the postal letter: the header is like the envelope, the payload is the entire content inside the envelope, the footer would be your signature at the bottom.. Network design can achieve two major results by using packets: error detection and multiple host addressing. Different communications protocols use different conventions for distinguishing between the elements of a packet and for formatting the user data. For example, in Point-to-Point Protocol, the packet is formatted in 8-bit bytes, special characters are used to delimit the different elements. Other protocols, like Ethernet, establish the start of the header and data elements by their location relative to the start of the packet; some protocols format the information at a bit level instead of a byte level. A packet may contain any of the following components: Addresses The routing of network packets requires two network addresses, the source address of the sending host, the destination address of the receiving host. Error detection and correction Error detection and correction is performed at various layers in the protocol stack. Network packets may contain a checksum, parity bits or cyclic redundancy checks to detect errors that occur during transmission. At the transmitter, the calculation is performed; when received at the destination, the checksum is recalculated, compared with the one in the packet. If discrepancies are found, the packet may be discarded. Any packet loss due to these discards is dealt with by the network protocol. In some cases modifications of the network packet may be necessary while routing, in which cases checksums are recalculated. Hop limit. If nothing was done the number of packets circulating would build up until the network was congested to the point of failure. Time to live is a field, decreased by one each time a packet goes through a network hop. If the field reaches zero, routing has failed, the packet is discarded. Ethernet packets have no time-to-live field and so are subject to broadcast radiation in the presence of a switching loop. Length There may be a field to identify the overall packet length. However, in some types of networks, the length is implied by the duration of transmission. Priority Some networks implement quality of service which can prioritize some types of packets above others; this field indicates. Payload In general, payload is the data, carried on behalf of an application, it is of variable length, up to a maximum, set by the network protocol and sometimes the equipment on the route. When necessary, some networks can break a larger packet into smaller packets. IP packets are payload; the header consists of optional fields. The payload appears after the header. An IP packet has no trailer. However, an IP packet is carried as the payload inside an Ethernet frame, which has its own header and trailer. Many networks do not provide guarantees of delivery, non-duplication of packets, or in-order delivery of packets, e.g. the UDP protocol of the Internet. However, it is possible to layer a transport protocol on top of the packet service that can provide such protection. The Consultative Committee for Space Data Systems packet telemetry standard defines the protocol used for the transmission of spacecraft instrument data over the deep-space channel. Under this standard, an image or other data sent from a spacecraft instrument is transmitted using one or more packets. Packetized elementary stream is a specification associated with the MPEG-2 standard that allows an elementary stream to be divided into packets; the elementary stream is packetized by encapsulating sequential data bytes from the elementary stream between PES packet headers. A typical method of transmitting elementary stream data from a video or audio encoder is to first create PES packets from the elementary stream data and to encapsulate these PES packets inside an MPEG transport stream packets or an MPEG program stream; the TS packets can be transmitted using broadcasting techniques, such as those used in an ATSC and DVB. In order to provide mono "compatibility", the NICAM signal is transmitted on a subcarrier alongside the sound carrier. This means that the FM or AM regular mono sound carrier is left alone for reception by monaural receivers. The NICAM packet (except for t Hannah Mayho is an English road and track cyclist from Cullingworth, West Yorkshire, a member of British Cycling's Olympic Academy Squad. A former county netball player and cross-country runner, Mayho began cycling in 2006 having been spotted at her school by British Cycling's Talent Team, she was coached by their coaches Phil West and Frances Newstead. At first she concentrated on athletics, seeing the pathway to success more defined in cycling, she chose to concentrate on that sport. A car collided with her on a training ride in May 2010, breaking her left leg and her right arm and wrist. A year after her accident Mayho returned to racing at the British National Time Trial Championships where she finished third in the Junior Women's event. Mayho went on to study for a BSc in Dietetics at the University of Chester. Hannah Mayho at Cycling Archives The Greenwell Baronetcy, of Marden Park in Godstone in the County of Surrey and Greenwell in Wolsingham in the County of Durham, is a title in the Baronetage of the United Kingdom. It was created on 19 July 1906 as part of the King's Birthday Honours for the stockbroker Walpole Greenwell; the Greenwell family still owns the land in Durham awarded them by William the Conqueror and from which they take their surname, as well as land in Suffolk and Inverness-shire. Sir Walpole Lloyd Greenwell, 1st Baronet Sir Bernard Eyre Greenwell, 2nd Baronet Sir Peter McClintock Greenwell, 3rd Baronet Sir Edward Bernard Greenwell, 4th Baronet The first Baronet had been High Sheriff of Surrey in 1903 and His Majesty's Lieutenant of the City of London. Walpole Greenwell, who fought in the First Boer War, became a member of the London Stock Exchange at age 21 and founded W. Greenwell & Co. which would become one of the wealthiest and most prominent stockbroking firms in the City of London. He was a keen agriculturist, a prominent breeder of pedigree stock Shorthorn cattle and Shire horses, for which he was awarded numerous championships, was President of the Royal Shire Horse Society. His Shire horse stud was considered the finest in the country. He was a trustee of the Whiteley Homes Trust, the Holloway Sanatorium, a member of the governing body of Royal Holloway College. Walpole Greenwell was succeeded by his son Major Bernard Greenwell MBE, who succeeded him as senior partner in the family stockbroking firm. Bernard Greenwell had been educated at Harrow and Trinity College, before serving in the Second Boer War where he earned the Queen's South Africa Medal with four clasps. In 1932 he took over as chairman of the County of London Electric Supply Company and expanded it to become the largest electric supply company in the country. Electricity distribution had been confined to urban areas, but under Greenwell's chairmanship supplies were extended in Essex and Dorset, he was keen to see electrical supplies provided for agricultural concerns. Like his father, he bred stock, in 1938 he purchased the entire herd of Shorthorn cattle reared by William Duthie at Collynie in Aberdeenshire, considered one of the best in the country. He farmed Marden Park and Butley Abbey Farm near Woodbridge, Suffolk. He was married to Anna Elizabeth McClintock, daughter of Admiral Sir Francis Leopold McClintock KCB. Peter Greenwell was High Sheriff of Suffolk for 1966–67. Edward Greenwell is a Deputy Lieutenant of Suffolk and was High Sheriff of Suffolk for 2013–14 Étienne Dedroog, known as The Lodgers' Killer, is a Belgian criminal and serial killer, responsible for killing a woman in France and the double murder of a Flemish couple. He is suspected of another murder in Spain. Dedroog was sentenced to life imprisonment for the double murder, 25 years for the France murder and is being investigated for the Spain killing. Not much is known about Étienne's early life, but it was known that he was attached to his mother; when she passed away in 2007, at the same time period he was getting a divorce, Dedroog experienced a mental breakdown the following year. According to reports from psychiatrists and psychologists, he has a "psychopathic personality", referring to his morbid egocentrism and tendency to manipulate others. Before settling in Crettaz's rural B&B home in Bouchet, Dedroog committed fuel fraud, as well as scamming tens of hotels and B&Bs in Châteauneuf-du-Pape, Vedène and Caderousse. In October 11, 2011, he killed the 57-year-old by cutting her external carotid artery, before stealing her credit cards and escaping in her car towards Spain. On the early morning of November 16, the 76-year-old López had decided to go fishing near the Cabo de Gata-Níjar Natural Park in Andalusia. After mentioning his intentions at a bar where he had breakfast, he travelled to a location called Cala Raja, only to be found dead on a gravel road with his car missing. Believed to be an accidental fall that had caused the death, it was revealed that López had been killed by a violent blow to the head with a rock, which had fractured his skull, his missing car was found on December 10 in La Jonquera, with DNA traces from the steering wheel matching those of Étienne Dedroog. At the time of the murder, Dedroog was in Almería. Authorities learned that between November 17 and 25, the suspected killer was spotted first in Valencia and Huesca before returning to Belgium. While examining the deceased's home, they found a bill issued in Dedroog's name from a hotel in Benidorm, disposed of in the wastebucket. After arriving in Grandvoir, Neufchâteau, Dedroog was directed towards lodging at the Blankaerts' house. Deciding that he wanted to steal their car, but was afraid that they would notice him, Étienne subsequently strangled the couple. He stole their car and a computer, before abandoning the car in Bruges. On December 1, Dedroog sent a message to his niece on Facebook, stating that he "does not recognize anymore", that "he did not deserve to be called a brother" and that "he had done more serious things than Ronald Janssen"; the day after, he surrendered himself to the police in Leuven. He confessed to killing the Blankaerts, on November 7, 2014, he was sentenced to life imprisonment by the Assizes in Arlon. However, he vehemently denied killign Crettaz, despite admitting that he had indeed stayed in her lodge on the date of death. Despite the best efforts of his defense team, Dedroog was sentenced to a further 25 years imprisonment by the French assize court. Since 2015, after a complete investigation, the Spanish police have suspected Dedroog as the killer of López, the lawyer has requested, on behalf of the victim's family, an extradition so he could face trial. The Turnip Prize is a spoof UK award satirising the Tate Gallery's Turner Prize by rewarding deliberately bad modern art. It was started as a joke in 1999, but inspired similar prizes. Credit is given for entries containing bad puns as titles, displaying "lack of effort" or "is it shit?". Conversely, entries with "too much effort" or "not shit enough" are disqualified; the first prize is a turnip nailed to a block of wood. The prizegiving is held at The New Inn in Wedmore, Somerset; the prize was conceived in 1999 by management and regulars of The George Hotel, Somerset, after the exhibition of Tracey Emin's My Bed was shortlisted for the Turner Prize. It is owned and organised by Trevor Prideaux and was announced thus: "The Turnip Prize is a crap art competition... You can enter anything you like, but it must be rubbish." The competition is based on the supposition, "We know it's rubbish, but is it art?". Competitors submitted entries of ridiculous objects posing as contemporary art made from junk titled with spoofs or puns. The prize is a turnip impaled on a rusty six-inch nail. In May 2000, the nominees appeared on the BBC TV Esther show, presented by Esther Rantzen and featured by national and international media. In 2001, the competition was held in the public conveniences in Wedmore. In 2002, the "Monster Raving Loony Party" attempted to hijack the competition at The Trotter, Wedmore. In 2003, the prize moved to the New Wedmore; the winner was James Timms with Take a Leaf out of My Chook, an exhibit of a raw chicken stuffed with leaves. James Timms subsequently appeared on BBC Radio Scotland's Fred MacAulay Show with Ed Byrne. In 2005, Ian Osenthroat, a 69-year-old former photocopier salesman, won with the exhibit Birds Flew, a bird's nest with a flu remedy box, he commented satirically, "I have entered this most coveted art award on several occasions and I feel that the lack of effort this year has paid off."Winner in 2006 was Ian Lewis with the exhibit Torn Beef, an empty corned beef can. He stated, "The work took no time at all to create." Trevor Prideaux commented, "I believe that over the last seven years the bad artists of Wedmore and surrounding areas have created far better works than Nicholas Serota and The Tate Britain Gallery could wish to exhibit." In 2006, the BBC's Chief Somerset Correspondent, Clinton Rogers, was immortalised as Clint on a Row of Jars. In 2007, the competition gained more publicity with the entry of artwork with the title By the Banksea; the painting bears a striking resemblance to work by the famous Bristol graffiti artist Banksy, its origins are a guarded secret. By the Banksea portrays a seaside Aunt Sally in the form of a stencil of the Mona Lisa, but in true Banksy style, Mona Lisa is depicted holding a rocket launcher firing a turnip over the wreckage of a seaside pier and an emergency exit sign. Competition organiser Trevor Prideaux commented: "It does seem to be in Banksy's style, but someone has tried too hard. So for that reason it's not to win." The piece was duly disqualified for "too much effort, not shit enough." The 2007 competition was won by Bracey Vermin with Tea P, a group of used tea bags in the shape of a letter P. Competition entries for 2010 included "Ivor Crush"'s clothes hanger linking the letter U in "Crush", entitled Hung up on You, an entry by Banksy, which focused on the recent student protests of the day. Entries for 2011 included a piece of cheese carved into the letter E, entitled CheeseE, A fish full of dollars, an exhibit of an Action Man toy – called First Class Mail – with a placed stamp, a coloured rock called Half a Stone Lighter; this year's prize featured on the BBC's Have I Got News For You for two weeks running.2012 – 87 entries.2013 – 69 entries, which included entries from Ireland, Italy and the USA.2014 – 69 entries, which included entries from Canada, USA, Italy.2015 – 69 entries, which included entries from France, Czech Republic and Macedonia.2016 – 99 entries, which included entries from Brisbane, Scotland, Northern Ireland, Lundy.2017 – 100 entries, which included entries from Guernsey and Germany.2018 – 90 entries, which included entries from Australia and Antigua 2019 - 107 entries, which included entries from Sydney, Australia and Belgium. This list is nearly complete 1999 – David Stone, winner – Alfred The Grate David Gannon – Sharp Infested Waters Neil Ellis – Soiled Serviette Iain Jones – Half Cut Maureen Hodge – Laundry Day Tracey 2000 – Jacqui Redman, winner – Minstrel Cycle Jenny Vining – Cereal Killer Kerry Bobbett – Wind In The Willows Sue Smith – Surf In The Net 2001 – Chloe Wilson, winner – nothing 2002 – Jenny Vining, winner – Piston Broke Dick Stelling – A Bit on the Side James Timms – Privot Investigator 2003 – James Timms, winner – Take a Leaf out of my Chook Di Vorce – Bitter and Twisted ( Coverham is a village in Coverdale in the Yorkshire Dales in North Yorkshire, England. It lies 2 miles west of the town of Middleham. Coverham was mentioned in Domesday Book in 1086, it became the centre of a large parish in the Honour of Richmond in the North Riding of Yorkshire, which included the townships of Coverham with Agglethorpe, Caldbergh with East Scrafton, Carlton Highdale, Carlton Town and West Scrafton. All these townships became separate civil parishes in 1866; the ruins of the Grade I listed Coverham Abbey are in the village and the site has no access to the public. Holy Trinity Church dates from the 13th century and became redundant in 1985, it is a Grade II* listed building. It is said to have a slope at its south east corner whereby the gradient is so steep, that though you are in the graveyard you cannot see the church nor hear the bells for the adjacent waterfall. Triple Crown winning jockey Harry Grimshaw is buried in the churchyard. Coverham Bridge, a medieval bridge over the River Cover, is a Scheduled Ancient Monument and Grade II* listed building.
- Ozone Hole - Urban outcome framework - Special Category status - Facts for Prelims 1 . Ozone Hole Context: The core (middle stratospheric layer) of the Antarctic ozone in mid-spring (October) has experienced a 26% reduction since 2004, contrary to previously reported recovery trends in total ozone, according to a study published recently in the journal Nature Communications. - The ozone layer resides in the stratosphere and surrounds the entire Earth. - UV-B radiation (280- to 315- nanometer (nm) wavelength) from the Sun is partially absorbed in this layer. As a result, the amount of UV-B reaching Earth’s surface is greatly reduced. UV-A (315- to 400-nm wavelength) and other solar radiation are not strongly absorbed by the ozone layer. - Human exposure to UV-B increases the risk of skin cancer, cataracts, and a suppressed immune system. UV-B exposure can also damage terrestrial plant life, single cell organisms, and aquatic ecosystems. - Ozone is also created close to the surface as a byproduct of pollution can trigger health problems such as asthma and bronchitis. What is ozone hole - The ozone “hole” is really a reduction in concentrations of ozone high above the earth in the stratosphere. The ozone hole is defined geographically as the area wherein the total ozone amount is less than 220 Dobson Units. - Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth’s atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth’s polar regions, which is known as the Ozone Hole. - Each spring over Antarctica atmospheric ozone is destroyed by chemical processes. This creates the ozone hole, which occurs because of special meteorological and chemical conditions that exist in that region. Causes of Ozone Hole - The main causes of ozone depletion and the ozone hole are manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants,and foam-blowing agents (chlorofluorocarbons(CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). - These compounds are transported into the stratosphere by turbulent mixing after being emitted from the surface, mixing much faster than the molecules can settle. - Once in the stratosphere, they release atoms from the halogen group through photodissociation, which catalyze the breakdown of ozone (O3) into oxygen (O2). Both types of ozone depletion were observed to increase as emissions of halocarbons increased. - In 1987, The Montreal Protocol was created to protect the ozone layer by phasing out the production of these harmful substances. - The Montreal Protocol on Substances that Deplete the Ozone Layer is the landmark multilateral environmental agreement that regulates the production and consumption of nearly 100 man-made chemicals referred to as ozone depleting substances (ODS). - When released to the atmosphere, those chemicals damage the stratospheric ozone layer, Earth’s protective shield that protects humans and the environment from harmful levels of ultraviolet radiation from the sun. 2 . IVF Context: The Congress has included in vitro fertilisation (IVF) as an area of focus in its manifesto for the Rajasthan Assembly election. About the news: - Integrating infertility with political agenda, Goa recently became the first State to offer free IVF, assisted reproductive technology (ART), and intrauterine insemination (IUI) services. - Maharashtra is also looking into providing financial support to people from rural areas for IVF treatments under the Mahatma Phule Jan Arogya Yojana. - In Vitro Fertilization (IVF) is a medical procedure where an egg and sperm are combined outside the body in a laboratory dish (“in vitro” means “in glass”). - This process involves stimulating the ovaries to produce multiple eggs, retrieving the eggs, and fertilizing them with sperm in a controlled environment. - The resulting embryos are then cultured and selected for transfer into the uterus, with the aim of achieving a successful pregnancy. - Children born through IVF are colloquially called test tube babies. - The Latin term in vitro, meaning “in glass”, is used because early biological experiments involving cultivation of tissues outside the living organism were carried out in glass containers, such as beakers, test tubes, or Petri dishes. Benefits of IVF - Treatment of Infertility: IVF is a highly effective method for couples facing infertility issues, providing them with the opportunity to conceive when natural conception is challenging. - Addressing Ovulatory Disorders: IVF can help individuals with irregular ovulation or those who do not ovulate, as it involves controlled ovarian stimulation to produce multiple eggs. - Age-Related Infertility: IVF can be a viable option for women of advanced maternal age, as it increases the chances of successful pregnancy by using younger donor eggs if necessary. - Same-Sex Couples and Single Parents: IVF enables same-sex couples and single individuals to have biological children by using donor eggs, sperm, or gestational carriers. - Preservation of Fertility: IVF offers the possibility of preserving fertility through methods like egg freezing, allowing individuals to postpone childbearing until a later time. Issues with IVF - Expensive: The WHO and the Indian Society for Assisted Reproduction (ISAR) studies show that one in six couples in India find it difficult to conceive a child, may require medical help, and treatment cost is expensive. The average cost of an IVF cycle ranges from ₹2.5 lakh to ₹4 lakh. - Social Stigma: Doctors in India explain that despite the high incidence of the problem, solutions for the diagnosis and treatment of subfertility, including IVF, remain inaccessible for many due to social stigma. They add that infertility can impact quality of life. 3 . Urban outcome framework Context: Urban Affairs Ministry starts data portal on cities for policymaking. About the news - The Union Ministry of Housing and Urban Affairs is making raw data from Indian cities available on a single platform for academics, researchers, and stakeholders to help data-driven policymaking. - The Amplifi 2.0 (Assessment and Monitoring Platform for Liveable, Inclusive and Future-ready urban India) portal was launched by the Ministry. - Currently, 258 urban local bodies have been onboarded, and data for 150 cities is available on the portal. - It is hoped that data from all 3,739 municipal corporations will eventually be made available on the portal. - The website provides data on a range of information for several cities, including total consumption; number of samples tested for water quality; average annual expenditure on healthcare; number of slum dwellers; and road accident fatalities. Urban Outcome Framework - Urban Outcomes Framework 2022 was launched as an initiative to undertake a transparent and comprehensive assessment of cities based on cross-city outcomes across major sectors. - The Framework includes the third rounds of Ease of Living Index (EoLI), Municipal Performance Index (MPI), Climate Smart Cities Assessment Framework (CSCAF) and Data Maturity Assessment Framework (DMAF). - It has been developed for the Ministry by the National Institute of Urban Affairs and PwC India. - It shifts the focus from the indices to data with a comprehensive list of indicators. - With this, data across 14 sectors are streamlined to increase focus on data collection, and disaggregated data can be analysed by experts. - The initiative also provides the opportunity to create new frameworks based on open data. Ease of Living Index (EoLI) - The Government of India, with support from various State and Local bodies, is running several flagship programs for urban development. With the purpose of making Indian cities more livable, MoHUA had launched one such initiative called Ease of Living index (EOLI) which assesses Indian cities based on various parameters across urban domains. - The aim of this index is to develop competitive spirit among the cities, which will eventually enhance the quality of life for the citizens through improvements across multiple dimensions like housing, transportation, utilities, mobility, ICT, health, education, economy, etc. Municipal Performance Index (MPI) - The governance of cities is determined by the functioning of Municipalities. They are the key agents that provide the enablers into making a city ‘Smart’. With this view, Ministry of Housing and Urban Affairs has launched the first ever Municipal Performance Index(MPI) to assess and analyze the performance of Municipalities across the country in all 100 Smart Cities and million plus population cities, based on their defined set of functions. - This index will act as a guide to evidence-based policy making, catalyze action to achieve broader developmental outcomes including the Sustainable Development Goals, assess and compare the outcomes achieved by municipal bodies, give citizens an insight into the functioning of local bodies and build a dialogue between the stakeholders. Climate Smart Cities Assessment Framework (CSCAF) - Cities while being the engines of growth and centres for economic, social & cultural development are also the biggest consumers of energy, and at risk due to the density of human population and the impacts of Climate Change. - Hence, in order to incentivize a holistic, climate responsive development in Indian Cities, Ministry of Housing and Urban Affairs has launched “Climate Smart Cities Assessment Framework” for the 100 smart cities. This is first of its kind Assessment Framework, aimed at creating a green mindset in the cities while they plan and undertake various development projects. Data Maturity Assessment Framework (DMAF) - As part of the DataSmart Strategy’s focus on “People, Process and Platform”, Data Maturity Assessment Framework has been prepared to drive effective use of data by our cities, and to help city leaders in structuring their approach to building a collaborative data ecosystem. - As India’s cities grow in their ability to leverage data, we will continue to evolve this Assessment Framework through its twin pillars of ‘Systemic’ and ‘Sectoral’ maturity to support cities in the most relevant manner possible in the context of their current maturity levels - The 14 sectors included are demography, economy, education, energy, environment, finance, governance, health, housing, mobility, planning, safety and security, solid waste management, and water and sanitation. 4 . Special Category status Context: On November 22, the Chief Minister Nitish Kumar-led Cabinet passed a resolution seeking the grant of special category status (SCS) to Bihar. The demand comes in the backdrop of the findings from the “Bihar Caste-based Survey, 2022”, which revealed that nearly one-third of Bihar’s population continues to live in poverty. What is a special category status? - It is a classification granted by the Centre to assist the development of States that face geographical or socio-economic disadvantages. - The SCS was introduced in 1969 on the recommendation of the fifth Finance Commission (FC). Five factors such as (i) hilly and difficult terrain (ii) low population density and/or sizeable share of tribal population (iii) strategic location along international borders (iv) economic and infrastructural backwardness and (v) non-viable nature of state finances, are considered before granting SCS. - In 1969, three States including Jammu & Kashmir, Assam and Nagaland were granted the SCS. - Subsequently, eight more States including Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Sikkim, Tripura, Himachal Pradesh, and Uttarakhand were given the SCS by the erstwhile National Development Council. What are the benefits attached? - The SCS States used to receive grants based on the Gadgil-Mukherjee formula, which earmarked nearly 30% of the total central assistance for States to the SCS States. - However, after the abolition of the Planning Commission and the recommendations of the 14th and 15th FC, this assistance to SCS States has been subsumed in an increased devolution of the divisible pool funds for all States (increased to 41% in the 15th FC from 32%). - Additionally, in the SCS States, the Centre-State funding of centrally sponsored schemes is divided in the ratio of 90:10, far more favourable than the 60:40 or 80:20 splits for the general category States. - There are several other incentives available to the SCS States in the form of concession in customs and excise duties, income tax rates and corporate tax rates to attract investments to set up new industries etc. Why is Bihar demanding the SCS? - The demand for SCS for Bihar has been made by various political parties of the State time and again. - The poverty and backwardness of the State are argued to be because of the lack of natural resources, continuous supply of water for irrigation, regular floods in the northern region and severe droughts in the southern part of the State. - Simultaneously, the bifurcation of the State led to the shifting of industries to Jharkhand and created a dearth of employment and investment opportunities. - With a per-capita GDP of around ₹54,000, Bihar has consistently been one of the poorest States. Highlighting the same in his fresh demand for SCS, CM Nitish Kumar, said that the State is home to around 94 lakh poor families and the granting of SCS will help the government get about ₹2.5 lakh crore required to fund various welfare measures over the next five years. Demands from other states: ? - Since its bifurcation in 2014, Andhra Pradesh has asked for a grant of SCS on the grounds of revenue loss due to Hyderabad going to Telangana. - Odisha has also been requesting for the SCS, highlighting its vulnerability to natural calamities such as cyclones and a large tribal population (nearly 22%). - However, the Central government citing the 14th FC report, which made a recommendation to the Centre that no State be accorded the SCS, has repeatedly denied their demands. Is Bihar’s demand justified? - Although Bihar meets most of the criteria for the grant of SCS, it does not fulfil the requirement of hilly terrain and geographically difficult areas, which is considered to be the primary reason for difficulty in infrastructural development. - In 2013, the Raghuram Rajan Committee set up by the Centre, placed Bihar in the “least developed category” and suggested a new methodology based on a ‘multi -dimensional index’ for devolving funds instead of a SCS, which can be revisited to address the State’s backwardness. 5 . Facts for Prelims Difference between Natural Gas and Biogas - On the basis of formation , Biogas forms in the presence of anaerobic bacteria. It is a naturally occurring gas which results from the breakdown of organic waste whereas Natural gas is a fossil fuel. - Sources: Biogas can be produced synthetically or from natural sources like agricultural waste, manure, municipal trash, plant materials, sewage, and other raw materials. Natural gas is produced from natural sources like plants, animals, and microorganisms that lived millions of years ago. - Energy Source: Biogas is an energy source that is both renewable and environmentally friendly. Natural gas is a nonrenewable energy source. - Production: Biogas is produced by biological processes that break down organic substances. Natural gas is produced by geological processes that break down organic materials. - Materials: Methane, carbon dioxide, hydrogen sulphide, nitrogen, hydrogen, and carbon monoxide are all found in impotent levels in biogas. Methane and simple alkanes are found in natural gas, along with trace amounts of carbon dioxide, nitrogen, hydrogen, and sulphide, as well as minute amounts of helium. All India Forward Bloc - The All India Forward Bloc (abbr. AIFB) is a left-wing nationalist political party in India. - It emerged as a faction within the Indian National Congress in 1939, led by Subhas Chandra Bose. - The party re-established as an independent political party after the independence of India. It has its main stronghold in West Bengal. - It held its first All India Conference in Nagpur in 1940. 3HP TB Preventive Drug - 3HP is a combination of 2 drugs, rifapentine and isoniazid, which are taken once weekly for 3 months to get rid of latent TB infection. - The 3HP regimen of one combination drug a week for three months translates to 12 pills in all. - Since treatment with 3HP involves only 12 doses, compliance is better and adverse effects are less. - TB Treatment using the 3HP drug is cheaper than isoniazid monotherapy for six months. Green Leaf volatiles - Green leaf volatiles (GLV) are organic compounds released by plants. - Some of these chemicals function as signaling compounds between either plants of the same species, of other species, or even different lifeforms like insects. - Green leaf volatiles are involved in patterns of attack and protection between species. - They have been found to increase the attractive effect of pheromones of cohabiting insect species that protect plants from attacking insect species. - When a plant is attacked, it emits GLVs into the environment through the air. - Piezoelectricity is a remarkable phenomenon whereby some materials including quartz, ceramics such as lead zirconate titanate (PZT), and even certain biological substances like bone and the tendons can generate an electric charge in response to mechanical stress. - This property is the result of their unusual crystal structures. - Usually, the charges on atoms in the molecules that make them up are symmetric on two sides of an axis. When some stress is applied, the molecule becomes distorted and the asymmetry of charges gives rise to a small electric current. - The term “piezoelectric” itself originates from the Greek words “piezein,” meaning ‘to squeeze’, and “elektron”, for amber which is a material known for its association with static electricity.
When you graph points in three dimensions, you are using a coordinate space as opposed to a Cartesian coordinate system. You are in fact graphing or plotting points in space. Take a look at the figure below to see what points look like in space. To go from the blue point to the red point, you could to do the followings although there are other choices. 1. Move to the right three units 2. Move backward two units 3. Move up 1 unit You have learned to graph on an xy-coordinate plane using ordered pairs. However, you need a third axis, called z-axis, to move from the blue point to the red point. This third axis turns the xy-coordinate into a coordinate space. Now, let us put some axes to see what a coordinate space looks like. Take a close look at the coordinate space in order to see where the coordinates are positive or negative. It is also important to notice the followings when you go from the blue dot to the red dots. Coordinate of the red point is (x, y, z) = (-2, 0, 1) Coordinate of the green point is (x, y, z) = (-2, -3, 2) Coordinate of the blue point is (x, y, z) = (0 -3, 0) Mar 29, 23 10:19 AM Mar 15, 23 07:45 AM
An acoustic wave can simply be described as a longitudinal wave. A longitudinal wave is a wave that vibrates and moves in the direction of its propagation. This means the medium is either in the same or opposite direction of the way the wave travels. Acoustic waves are a form of Mechanical longitudinal waves; these waves are otherwise known as compression waves or compressional waves. Compressional waves obviously produce compression, decompression, and rarefaction to travel. In Physics, the acoustic wave has an equation to describe the evolution of acoustic pressure and particle velocity as a function. The general equation is: Acoustic waves have multiple equations, but this version is the simplified form. In a simplified acoustic wave equation there is only one spatial dimension. In other more complex equations there is a possibility of two or maybe even three dimensions. The letter “p” in the general form equation pictured above is to show the acoustic pressure . The letter “c” represents the speed of sound. Both acoustic pressure and speed of sound are the key ingredients to describing the behavior of sound in matter. A solution for this particular acoustic wave equation is: “F” and “g” both show two twice-differentiable functions, and “c” again, is the speed of sound. After reading the first paragraphs you may be wondering why are acoustic waves so important in normal life or “why would I ever need this equation?’ Acoustic waves are important because sound is all around us. When you think of the word “acoustic” a few words may come to mind. Guitars, stereos, and many other items involve acoustic waves. For example, when the bass on a stereo is turned all the way up you m... ... middle of paper ... ...smits the waves from one direction but as soon as it reflects it blocks them from the other. Many people hear both terms, acoustic and sound waves and think they are basically the same. That seems to be untrue because sound waves do not have polarization. The reason why they don’t have polarization is because sound waves oscillate in the same directions they move. This means sound waves cannot reflect while acoustic waves can. For example, when you are in a domed shaped building the acoustics allow you to hear an echo or a projection of a noise from the other side of the room. There is not many information on acoustic waves but it was interesting researching this topic. The little that I found was really cool and I’m glad I did this essay on such a topic. Acoustic waves are all around us and are important in science. Need Writing Help? Get feedback on grammar, clarity, concision and logic instantly.Check your paper » - Stringed instruments are most likely the oldest type of musical instruments. The acoustic guitar has been around since the 1500's, and is the most common stringed instrument used today. The guitar is one of the most versatile instruments in existence, being used in virtually every style of music. It can produce a wide range of sounds depending upon the style of the guitar and the type of strings used on it. The two main styles of acoustic guitars are the nylon-stringed and the steel-stringed.... [tags: physics guitars] 1810 words (5.2 pages) - Physics of an Acoustic Guitar I have been watching my husband play the guitar in a band for five years and he has made it look so easy to make such beautiful music. Most guitar players have progressed with the technology of electric guitars, but when my husband picks up an acoustic guitar and starts to play a song for just me, I hear his love for me in the sounds that he produces. Imagine my surprise when a physics class conveyed to me that there was much more to his playing than I had imagined.... [tags: Music Instruments Essays] 1748 words (5 pages) - ... As the sound is propagated outward, it is “spread” over a greater area. The minimum sound intensity that can be detected by the human ear (called the threshold of hearing) is about 10-2 W/m2. At a greater intensity of about 1W/m2, sound becomes painful to the ear. The frequency of a sound wave, seeming as pitch, is the number of compressions (or rarefactions) that pass a fixed point per unit time. The frequencies audible to the human ear range from approximately 20 hertz to 20 kilohertz. Intensity is the average flow of energy per unit time through a given area of the medium and is related to loudness, (Shipman-Wilson-Higgins, 2013).... [tags: frequency, pitch, waves] 876 words (2.5 pages) - Almost everybody can appreciate guitars. Guitars are at the forefront of music as the centerpiece of most bands. Guitars are a highly versatile instrument capable of playing full 6 note chords, unlike most instruments. As much as music depends on guitars, guitars also depend on physics. Without understanding the properties sound, guitars wouldn’t be possible. Guitars use the principles of acoustics to produce the sound you hear. Acoustic guitars and electric guitars produce sound in two different ways.... [tags: physics guitar] 2349 words (6.7 pages) - Sensor is a device that responds to a physical, chemical, biological or electrical stimulus as an electrical output signal which is a function of input stimulus. The device responds to the input stimulus by monitoring the change in oscillation frequency for acoustic waves. INPUT SOURCES The input stimulus could be physical such as changing pressure, temperature or stress. It also may be chemical such as particular gas concentration or the chemical agent. It also include biological input stimulus which include bacterial concentration, antibodies concentration.... [tags: acoustic, particulate, stimulus] 2391 words (6.8 pages) - Introduction: The guitar is a typical string instrument, whose physics are similar to many other string instruments. The main parts consist of the body, the neck, the bridge, the tuning pegs, the sound hole, and the strings. An electric guitar lacks the sound hole and instead relies on an amp for amplification. The physics of a guitar involves sound waves, how they are amplified, and how they travel. Strings: The vibration of the strings of a guitar causes the sound wave, but is not actually what you are hearing.... [tags: music, string instruments, vibration] 975 words (2.8 pages) - The Physics of Ultrasounds Without the use of physics in the medical field today, diagnosis of problems would be challenging, to say the least. The world of medical imaging in particular has benefited greatly from the use of physics. Ultrasound is sound waves that have a frequency too high for humans to hear. With a shorter wavelength than audible sound, these waves can be directed into a narrow beam that is used in imaging soft tissues (Farr and Allisy-Roberts 183). As with audible sound waves, ultrasound waves must have a medium in which to travel and are subject to interference.... [tags: Medicine Medical Technology Essays] 1713 words (4.9 pages) - INTRODUCTION When an object vibrates, the medium in which it is directly adjacent to create a mechanical disturbance, this creates sound. Sound is a pressure wave which travel through the medium which is usually air. The medium then carries the pressure waves to the ear of a person or animal. For example, when a guitar string is plucked, the string starts vibrating violently creating a pressure wave which travels through the medium and to an ear were the sound is heard. The equation of a sound wave is speed= wavelength x frequency.... [tags: frequency, vibration, waves] 816 words (2.3 pages) - The electronegative plasma can be defined as a plasma that contains both electrons and positive ions, as well as negative ions. This type of plasma is a subject of continuing interest thanks to its importance in various fields of plasma science and industry and its existence in astrophysical, space, and laboratory experiments plasmas. The electronegative plasmas have been generated in Laboratory by many different methods a1,a2. Negative ions plasmas are found in many space observations such as (H⁺-H⁻) and (H⁺-O₂⁻) plasmas have been found in the D- and F-regions of the Earth 's ionosphere a4.... [tags: Electric charge, Ion, Electron, Plasma] 1231 words (3.5 pages) - The concert hall is one of man's greatest joys; enjoying a fine symphony composed by the worlds greatest, performed by a world class orchestra. For months afterwards, the borgoise attendees will speak of the energy of the conductor, the orchestra responding to him, the power of it all. The crescendoes, the diminuendos, the stark silences between movements, the clarity of the soloist above the rest of the orchestra. Little do they know that were it not for the meticulous consideration of the architect at construction time, the patrons would not feel that they were getting their money's 'worth.' The architect is tapping into the world of acoustics; in this case, achieving the best possible so... [tags: acoustic acoustics sound] 2781 words (7.9 pages)
Many machine learning tasks require high-quality data, such as assessing damage in a satellite that negatively affects a model’s performance. Datasets can cost millions of dollars to create if useable data exists, and even the best datasets sometimes contain biases that negatively impact a model’s performance. Many scientists have been working to answer an intriguing question working with synthetic data sampled from a generative model instead of real data. A generative model is a machine-learning model that requires significantly less memory to keep or share than a dataset. The range and quality of generative models have improved dramatically in recent years. Synthetic data has the ability to get around some of the privacy and usage rights problems that limit how actual data may be distributed. A generative model could potentially be updated to eliminate particular attributes, such as race or gender, to overcome biases in traditional datasets. New research by MIT Team develops a method for training a machine learning (ML) model that, rather than requiring a dataset, employs a particular form of ML model to generate exceptionally realistic synthetic data that can train another model for downstream vision tasks. Their findings suggest that a contrastive representation learning model trained solely on synthetic data may develop visual representations comparable to, if not superior to, those learned from actual data. After a generative model has been trained on actual data, it can generate synthetic data that is indistinguishable from the original. The training method gives the generative model millions of photos containing objects in a specific class (such as vehicles or cats), after which it learns how to generate comparable objects. This pretrained generative model can then be used to generate a steady stream of unique and realistic images based on those in the model’s training dataset by just turning a switch. The team explains that generative models are more beneficial since they learn how to modify the underlying data that they are trained on. For example, a model trained on photos of vehicles can “imagine” how a car would look in new scenarios — situations it hasn’t seen before — and then generate images representing the car in different positions, colors, or sizes. Multiple views of the same image are necessary for contrastive learning, which involves exposing a machine-learning model to many unlabeled images to learn whether pairs are similar or different. To enable two models to work together automatically, the researchers linked a pre-trained generative model to a contrastive learning model. They believe that a generative model can aid the contrastive method in learning more accurate representations because the generative model can provide multiple perspectives on the same object. The team discovered that their model performs better when compared to a number of different image classification models trained using real data. A generative model has the advantage of being able to generate an endless number of samples in principle. As a result, the researchers looked at how the model’s performance was affected by the number of samples used. They discovered that increasing the number of unique samples generated in some cases resulted in even more benefits. These generative models are already trained, are available in online repositories, and can be used by anyone. The team remarks that these models can reveal source data in some situations, posing a privacy concern. Furthermore, if not adequately trained, they can accentuate biases in their trained datasets. The team plans to address this issue in the coming future. In addition, they also aim to explore methods to use this technique to generate corner cases that could help machine learning models improve. Most of the time, real data cannot be used to learn about corner cases. For example, if researchers develop a computer vision model for a self-driving car, genuine data would not include examples of a dog and its owner sprinting down a highway. Therefore the model would never learn what to do in this scenario. In some high-stakes circumstances, synthetically generating that corner case data could boost the performance of machine learning models.
learning for children is a complex process that starts at birth and continues through adolescence. All children can learn within the limit of their inborn potentials. However, given nearly equal capacity, some children become more effective learners than others. Yes, the extent to which the learning process culminates in knowledge, skill, ability, insight, awareness, academic success, and other forms of achievement related to learning depends in large measure on how well the child learns to learn. Let us look at a few areas in which children learn how to learn and at how parenting adults can help. LEARNING BY OBSERVING: Much of what children learn comes from observing people, situations, and things. The principle is not complicated but is extremely important. For example, an infant observes people wave and say 'bye-bye' when they leave. Through numerous observations, she gradually learns the custom of making some kind of parting comments and gestures upon leaving. She also learns to talk by observing people talk. While most learning through observing takes place spontaneously, as parenting adults, we can still do quite a lot to maximize it. First, we can encourage the child to be observant. For example, our child hears some music and asks if we like the song. We could say yes and let it go at that, or, we could encourage the child to sit down for a few minutes and listen with us. As we listen, we might call his attention to different instruments, how the voices complement the instruments, and the like. If we do this with enthusiasm, he may well pick up an appreciation for music, including the all-important ability to listen carefully. As mother cooks, she might encourage her child to taste the food as it is being prepared and to be aware of the flavors and Second, we may want to take our child someplace special, or bring something unusual home to him. For example, mother picks up a turtle by the roadside which she takes home to show to the child. Or the child's uncle works at a pumping station and one evening shows his nephew the plant If we orient ourselves to making observation opportunities available to our children, we will quickly find that interesting and unusual opportunities come up several times a week. We must encourage our children to carefully observe with all of their senses, help them to be more aware of what they are observing, and look for opportunities for observation from the unimportant to the highly unusual. LEARNING THROUGH IMITATION: Children readily imitate the behavior of others, like talking and eating. How can we as parenting adults help our children learn through imitation? First, we can encourage a 'show me how' attitude - we observe a toddler playing with blocks on the floor, so we sit down, play for a while, and demonstrate some of the possibilities for playing with blocks. We come back later and notice that the toddler is doing some of the same things we had done. Later, while playing with some other toys, he asks, 'Show me how to play.' He has picked up the idea of finding someone who knows how to play to imitate. Or, a grade schooler asks if he can use the electric hair dryer. We say, 'I'll have to show you how to use it.' He says, 'I already know how. I watched you.' Children need to learn to be selective about whom they imitate, how to find people who know how, how to get other people to show them how, and how to express appreciation when someone has taken the time to show them how. Children who know when and how to find someone to show them how, and how to get them to show them, are a big step ahead of children without these skills. We want to show children how to do things, but may not want to do things for them. For example, a grade schooler wants to know how to do a particular arithmetic problem. We carefully show her how to do the problem. Did she really learn how, or did she simply 'con' us into doing the problem for her? We say, 'Now I want you to do another problem, to show me you really know how to do it.' She may object a little, but will soon come to understand that once we have shown her how to do something, we expect her to demonstrate what she has learned. This encourages her to observe more closely and to really imitate the behavior. When children learn how, we want to encourage them to use reference books and other resource materials. They need to learn how to interpret diagrams, follow instructions, recipes, and the like. They will gradually develop the skills of observing, reading, asking questions, and LEARNING THROUGH TRIAL AND ERROR: Learning by trying something, doing it wrong, and then trying again, is important and is to be encouraged. At the same time, though, we should aim to help the child do a thing correctly the first time around. For example, your grade schooler is gluing together a plastic model. Since it will be difficult to take apart once put together, it is fairly important that she learn to do it right the first time. Of course, she will develop increasing skill through practice, i.e. through trial and Children need to learn to 'consider the possibilities.' Putting puzzles together is a good example. Exploring the possibilities comes up in numerous situations. Any time a child wants us to decide, to tell him how, to choose, or to figure out the right answer, we should consider the possibility of suggesting that he consider the possibilities. Yes, at times we will show him how, give him the answer, or solve the problem. Much of the time, though, we should encourage trial and error and explore various possibilities. This approach to learning will have the very desirable side effect of helping the child become socially and A second concept involved in trial and error learning might be thought of as successive approximation. Our first approach to a problem does not work or turns out incorrectly. We then look at why it did not work, and our next effort takes this into consideration; we come a little closer. For example, an adolescent hurriedly paints a fence. She steps back, observes a few missed spots, and touches them up. Her hurried effort approximated a good job and her touch-ups really got the job done. Writing a theme for school goes through successive How do we as parents help children learn to use successive approximations? We encourage them to look critically at what they have done and to try to improve on it next time, whether it is their behavior while visiting a friend's house or school work. We encourage an orientation to successive approximation when we refrain from always giving the correct solution, or telling how to do something. Learning through mental rehearsal may be the highest learning skill. What do we mean by mental rehearsal? Learning through mental rehearsal is more of a thinking process than a doing process. We imagine in our mind's eye or ear what something would look or sound like. We mentally try out each of the possibilities for solving a problem or completing a task, as if we were actually doing it. How do we help a child to use her capacities for mental rehearsal? If your child is presented with a problematic situation and asks what should she do, we say, 'Let's think about it for a little while before you do anything. Let's see if we can imagine all the ways of dealing with it, and then think through what will happen if we follow each of the possibilities.' We are encouraging the child to use mental rehearsal as well as demonstrating the technique. If your adolescent is experiencing a lot of anxiety about a debate, we can say, 'Imagine yourself in the room where the contest is going to be held. Now imagine that the debate is about to begin and think through everything that is going to happen (in sequence) before your turn. Now it is your turn. Think about getting up, walking to the microphone, looking at the audience, and giving your speech. Run this through a few times in your mind to see what the problems might be, what other people are going to do and say, and what you are going to say. Make mental notes about what you are not sure of, and what you need more information about.' After the debate, the adolescent says, 'It was not as bad as I thought it was going to be. It was almost like I had been It is really true; she had been there before, in her mind. With a preschooler, we would want to encourage her to slow down and think things through a little before starting an arts and crafts project, or participating in a special ritual at church, or making her first solo excursion to the grocery store. With a grade schooler, we would want to encourage her to think through an arithmetic problem before starting to work it, or how she is going to hold the bat before her turn at plate, or how she is going to get to school the first time she tries it on her own. There are innumerable opportunities for mental rehearsal, and children should be made consciously aware of the technique and encouraged to use it. LEARNING ABOUT THINGS AND RELATIONSHIPS: Children need to learn a lot about a lot of things - from needles to calculators, from wedges to measuring cups, from flashlights to bulldozers. People who know what tools are for and how they are used have an advantage over people who do not. There is a similar advantage for people who know about games and toys, objects around the house, works of art, or almost How do we help our child to know as much as possible about as many things as possible? We try to answer her endless questions about things, call her attention to things, we encourage her to ask others questions about things, we take her to museums and art galleries, we read to her about things and encourage her to read about things. We also take time to look at something special or interesting, to show the child things we observe when shopping, we ask questions about things that interest her. In addition, we point out things, give the names of things, explain what things are for. Money is a special thing. Children need to have money, need to learn what can be purchased with their money, need to be able to tell how much money they have, and need to develop appropriate attitudes toward money. Before a child learns to add and subtract and to tell the different pieces of money from each other (about six-years-old), she should have some money of her own, be encouraged to spend it on things she wants, be allowed to listen to adult discussions about money, and told how much things cost. Of course this can be overdone, making the child too conscious of cost, or apprehensive about whether or not there will be A few examples: A seven-year-old picks out a toy car costing $1.81, but has only $1.70 to spend. Should we simply pay the other $0.11? Generally not. We should simply tell her that if she wants the toy car, she will have to save more money or suggest that she pick out a toy that does not cost so much. Another possibility is to tell the seven-year-old, 'I will loan you the $0.11 and you can pay me back as soon as you get more money.' If the child agrees, remember to ask her for it the next time she gets some money. Our twelve-year-old tells us he should get paid for doing things around the house. Do we agree to pay him? Probably not. Being a member of the family and living in the house involves sharing responsibilities. Household jobs are not something for which anyone gets paid; everyone is expected to help. You may decide he has a right to some spending money which he can count on having. This allowance is one of the rights shared by responsible members of the household. If some week you do not have money to give to him, he will have to do without but still do the work assigned him. Children should be expected to share in the responsibilities of the household and should also have a right to share in the resources available to the family. Should children be forced to save part of their money? Probably not. Most children need to learn to handle their small amounts of money responsibly. If a child has, say $50, we might insist he save part of it. Even in this situation, though, he should have the right to spend it on Should children have pets? Yes, if at all possible, because they learn a lot about relationships with people through their relationships with pets. In addition, they learn how to take care of animals and to develop good feelings toward animals. Through a relationship with a kitten, for example, a child learns the importance of playfulness combined with gentleness, respect for the kitten's autonomy, the responsibility that goes with love, and seeing that the kitten has food and water. The same is true with other pets. Children also learn from their pets about death, illness, and injury. Pets offer children one of the best ways to learn about relationships. Very young children, of course, cannot accept full responsibility for pets. Parents need to help small children, but should not accept responsibility for it themselves. In addition, children need to be shown how to hold pets, play with them, not abuse them, see that they do not get lost or injured. Parents should insist that children accept these responsibilities, consistent with the child's age, and actively show them how to deal with the pet. Relationships are not taught in school, so parenting adults must take the responsibility for teaching children about relationships. You might be talking about friends and say, 'There are a lot of different kinds of relationships.' You could then go on to talk about what is different about Consider two children who are about to deal with a new type of relationship. The child who has thought about relationships in conscious terms can think, 'Visiting Grandma in the hospital will probably be a little like visiting her at home, plus a little bit like visiting Aunt Jenny at the nursing home.' On the other hand, the child who does not make the comparison automatically, will have to have it explained to him in his own terms. LEARNING ABOUT PEOPLE AND SITUATIONS: How can we help our children learn to deal with people as unique individuals, not as stereotypes? First, we should encourage our children to talk with our friends, to say hello to most people with whom they come in contact, to make a variety of acquaintances, to play with a wide variety of children. We should talk with them about people we know or have heard about. Learning about people begins with exposure to as many people as possible, even objectionable people at times. As parenting adults, we should help our children interact and talk with the people with whom they come in contact. We learn the most about people when they tell us about themselves, their interests and experiences. When our child talks about his friends, we might ask him to tell us what is interesting about them, to give examples of interesting places the friends have been, things they like to do, and so on. This helps them to think about people's unique and positive qualities, as well as their negative characteristics. When we introduce our child to someone else, we might tell the other person something that we find interesting about our child: 'This is Sally; she has been working on a 4H project.' When we introduce one of our friends to our child, we might say, 'This is Ann Smith. She is interested in ceramics.' Similarly, we might encourage our child to do the same. When he introduces one of his friends, we might say, 'It is nice to meet you,' and (turning to our child) ask 'Can you tell me something interesting about Billy so I will know him a little better?' Learning about situations follows the same principles as learning about people. The greater the variety of situations with which a child is familiar, the better prepared he is to effectively handle himself. If parenting adults encourage a wide range of situational experiences, the child will be better prepared to function socially. In addition, parents can talk about situations they have been involved in, and encourage the child to do the same. The child can learn about similarities and differences within situations, things he likes or dislikes, appropriate and inappropriate ways to behave. Even more importantly, the child can develop awareness of what is unique in each situation. Examples: After a friend has left, mother says to her toddler, 'I noticed that you and Julio had a lot of fun and did not get into any arguments.' Our adolescent talks briefly with a friend but does not introduce him to us. We say, 'I was surprised you did not introduce your friend to me.' Specific situations and incidents come up all the time. It is important for the child to look at these situations one at a time and to add his understanding to his knowledge about situations. Parents often raise questions about whether or not children should be exposed to specific situations. Let us consider a few of these. Should children be taken to funerals? Yes, especially if the deceased was close to the child, because death and funerals are important situations in which children need to know how to behave. Should children be taken to weddings? Yes. Weddings present a good opportunity to talk about marriage, and love relationships. Should children be taken to hospitals? Yes, if possible. They may get uneasy, but these are parts of life about which children need to learn. When we protect children from normal life situations, we are neglecting opportunities where we can talk about the situation and deal with their feelings. SANTA CLAUS AND THE TOOTH FAIRY: Occasionally, we talk with parents who say that they do not believe in telling their children about Santa Claus, the tooth fairy, the Easter bunny, or even fairy tales. Their idea is to be truthful. Should children be exposed to nursery rhymes and fairy tales? Should they engage in fantasy? Yes, fantasy is not only harmless, but extremely important in developing the child's imagination and creativity. As we talk with a child about fantasies and fairy tales, tell her that fairy tales are fairy tales, fantasy is fantasy, and neither are true. The ability to discriminate between real and unreal, between those times when people are telling us how it really is and when they are 'putting us on,' is extremely important. Fantasies and fairy tales help a child make these discriminations. In addition, involvement in fantasy and fairy tales allows a child to imagine and dream, and create new worlds. Most innovative and creative adults were great fantasizers as children. Encouraging young children to believe in Santa Claus, the tooth fairy, the Easter bunny, and so on represents a slightly different type of parenting problem. Should these myths be perpetuated? Again, yes, they are a lot of fun, are very meaningful to children, and become an important part of the childhood we remember. Santa Claus and the tooth fairy are positive notions for children, and have no negative consequences. Let us look briefly at the typical objections and then consider a few real advantages of Santa Claus and the tooth fairy. Magical beings do not exist; children should not be taught that they do. For the young child, magic is a convenient explanation for almost anything they do not understand. Santa Claus and his magic represent a reasonable explanation to the toddler and preschooler for Christmas toys. Once a grade schooler, the child quickly raises doubt about the existence of Santa Claus. To suggest that the child will not understand the myth of Santa Claus, or continue to hold distorted notions of reality reflects a real misunderstanding of the mental ability and perceptive skill of the grade schooler. The spirit of Santa Claus lives in us all and our childhood experience has led us to want to give occasionally without receiving. Hopefully, the myth of Santa Claus is one way in which we (as parents) can help instill such values in our children. The tooth fairy simply takes lost teeth and leaves money. Is there any harm in this myth? No. Children learn by the time they are seven or eight that the magic of the tooth fairy comes from Mom or Dad's coin purse. While the child is still a true believer, the tooth fairy adds a little fun to the process of losing baby teeth. Parents occasionally ask what to do if they forget to put money under the pillow or are unable to find the tooth. A child finds it quite acceptable if parents say that the tooth fairy must have been too busy, and will perhaps stop by the following night. Also, it is quite easy to go into a child's room and pretend to find the money someplace other than where she had expected it, and simply tell her that the tooth fairy must have been in a hurry and didn't have time to put the money under the pillow. What about the teeth that were too far under the pillow to risk awakening the child? Sometimes, the tooth fairy has more teeth than she needs. Will the child still leave the same tooth under the pillow again? No. The tooth fairy pays up only once. As you can see, the involvement of a child in fantasy, fairy tales, myths and magical beings and so on is fun and has no negative consequences. In fact, the consequences contribute significantly to a child's lifelong creativity, imagination, and overall ability to think beyond the present and beyond the particular reality within which he lives. In addition, the child who has been exposed to Santa Claus, the tooth fairy, and other such myths has the opportunity to learn that part of the world in which he believed implicitly was not the way he thought is was. To a small extent, this makes him a little skeptical, a little less gullible, and a little less likely to take things on faith. Also, he learns that even Mom and Dad may be wrong, and may tell him things that aren't completely true. A little skepticism is healthy and productive. Some parents have the belief that their child's success in school is something over which they have no control. They are mistaken. As a general principle, we should start out assuming our child has average or slightly better than average ability and then be sure he is learning as much as he can. How do we do this? First, we need to create a healthy, stimulating home environment. Children need to come to school as healthy physical/doing, emotional, moral/spiritual, social individuals. They need to feel positive about being in school. They must be able to relate to teachers and conform to their expectations. With such a background, a child comes to school with enthusiasm, prior experience, and a readiness to take on the world of school. No, it is not important that a child be able to read, count or write numbers, or spell and print before getting to school. If another parent says that their child could read by the age of four, knew the alphabet before going to school, could count to one hundred before entering kindergarten, or the like, there is no reason to be alarmed. School is a good enough place to learn these things; our emphasis before our child gets to school should be on his physical/doing, emotional, moral/spiritual, and social development. Once children are in school (kindergarten through high school), active parental involvement is extremely important. Since in general the more interest in a child that is shown by her teacher, the more academically successful the child will be, we want to maximize this attention. We do this by demonstrating our concern for our children. We should always go to scheduled parent/teacher conferences. We should make an active effort to attend school functions, including PTA, special programs and school events. Where possible, we can become volunteer room parents, help with school projects, or serve on committees. We can even say hello to the teacher when we pick up our child from school. If our child shows signs of difficulty, we should telephone the teacher and otherwise let the teacher know we are vitally interested. Don't become a nuisance, of course. Next, we should be restrained in approaching the school or teacher about problems, which are generally fairly minor, anyway. Also, children frequently distort what has happened at school to make themselves look better and the teacher worse. We should let these difficulties pass unless particularly severe or repeated. We should save our disagreements with the school for important issues. All of us will probably have at least one problem with the school during the child's school years. If we have a history of being cooperative, interested, and understanding, our credibility will be good when we need to call a serious problem to the attention of the school. Next, we should take major responsibility for monitoring the academic progress of our children. For children of grade school age, we should insist they regularly bring home their papers and school projects. Most of the time, we should look over this work and specifically note any errors. When we find a problem answered incorrectly, we should calmly go over it with the child. Emphasize the positive, but be sure the homework is corrected by the child. Don't make a big deal of this process - helping a grade schooler with homework should normally take no more than thirty minutes. Any longer and you should talk with the teacher about the problem. It is important that a child have a place to do his homework (loud radios and TVs seem not to be particularly distracting to children) and that he be encouraged to do all homework. If a child is having difficulty at school, he should spend time every evening on school work, whether or not homework has been assigned. (Twenty minutes is long enough for first and second graders; an hour is reasonable for high school students). Check with teacher from time to time to see if homework is being completed and turned in on time. It is also important to look at high schoolers' books once in a while, and to look over their homework papers, and ask questions about their studies. Make an active effort to see they do their work. If a child has special difficulties you are not prepared to help with, first talk with the teacher and then arrange for special help if necessary. Perhaps another high school student can tutor. Most high school teachers are quite willing to give extra help, if the student shows interest and asks for it. School is fun and enjoyable, but it is also a lot of hard work. A child may not like all subjects, every teacher, or doing school work. Especially with a high school student, you must be firm about your expectation to do well with school work, to get along well with teachers, and to conform to parental and school expectations whether or not she likes every aspect of school. Succeeding academically is a child's work and is one of her major responsibilities. PIANO LESSONS AND OTHER EXTRACURRICULAR INSTRUCTION: In addition to school courses, children take many kinds of lessons: music, art, dance, swimming, tennis, singing, and so forth. Such lessons may be just for fun or for developing a skill; they may be for a set number of weeks or continued indefinitely. This makes four categories: (1) lessons just for fun and for a fixed period, (2) lessons just for fun but for an indefinite period, (3) lessons for developing a skill and for a specific period, (4) lessons for developing skill and for an indefinite period of time. This structured learning is added to the regular schoolwork. Now, although education is a good thing, enough is enough. If children spend six or seven hours a day within a structured learning environment, more is abusive and leaves too little free time. No child should take more than three types of extracurricular lessons; in fact, one or two is probably quite enough. A rule of thumb might be that the lessons (including practice) should take no more than five hours total a week for any child. Lessons just for fun and for a specific time period should be totally at the child's option, following the maximum time guidelines suggested above. If a child wants to take such a lesson for a few weeks, and if time is reasonably available, she should be permitted to, assuming there is a qualified teacher. The child should be expected to attend all of the meetings and to follow through to their completion. Lessons just for fun and for an indefinite period of time are somewhat different. For lessons of this type, we are making a long-term commitment to pay for the lessons, and to arrange for the child to be present. Should the child be made to continue the lessons if she becomes bored or decides she does not like them anymore? Suggested rule: Tell the child she can, at any point, let you know if she wants to stop. After that, she must take three more lessons. If after taking three more lessons, she still wants to quit, then she can. Remember, these lessons are just for fun anyway. If they are no longer fun, they are no longer important. The third type of lessons are for a limited duration and for developing a specific skill or talent. Using swimming lessons as an example, should a child be made to take swimming lessons? Swimming can be learned within a limited time and is an important skill. Yes, the child should be made to go to swimming lessons and to follow through with the course whether interested or not. Piano lessons are a good example of lessons developing specific skills and talents over an unlimited duration. Should a child be made to take piano lessons? Probably not. The child is unlikely to do well, and can easily develop negative attitudes and resistance unless initially interested. Most young children, however, are quite interested in these types of lessons, at least initially. They want to learn to play an instrument or to develop their artistic talents. In time, the lessons may get tedious. It is a lot of work to learn how to play the piano. Should we insist that the child practice? Should we allow him to quit if he wants to do so? Without practice of this type, lessons are a waste of time and money. No, the child may not want to practice. Even if he gets fairly upset about it, we should insist he practice for at least thirty minutes a day or that he practice each assignment three or four times a day. Piano or other skill-development lessons are frequently more important to us than to the child. We can say to the child, 'We want you to learn how to play the piano and think that it is a good thing for you to pursue music. This means you will have to practice on a regular basis whether you want to or not.' It is unlikely this will cause the child to resent music or other lessons. The child's increasing skill will be reinforcing and any praise he receives will be encouraging. Nonetheless, if practicing and taking lessons is a daily problem over a period of months, and if the child's skill does not seem to be developing, then there is no point to continuing the lessons. Yes, children should at times be allowed to quit. In reference to this type of lesson, though, the final decision should remain with us. It is our responsibility to encourage and sometimes insist that these skills and talents be cultivated. RIGHTS AND RESPONSIBILITIES: Parents of older grade schoolers or adolescents often say their children do not appreciate the good life they have nor the efforts parents make. In reality, there is no particular reason why a child should be especially grateful about the opportunities and things available to her. After all, the child has grown up in a family environment where such opportunities automatically are available as a member of the family. Real appreciation can only develop over time. Appreciation develops when, as an adult, the individual realizes that these things did not come easily or naturally. Also, the grade schooler or adolescent will begin to appreciate the opportunities she has in relation to other children who have less. As children's lives expand from their involvement with the family to involvements with other groups, they gradually learn that certain rights are inherent in membership in these groups. For example, they learn they have rights at school, such as the right to have teacher help with problems or the right to materials and supplies. They learn they have certain rights within It is very important that we parents actively help our child learn about her rights as an individual, as a family member, as a member of other groups, as a member of the community. For example, if our grade schooler is refused a turn at bat because others won't let her, we might say, 'If I were you, I would not play ball with them anymore if they are not going to let me have a turn at bat.' Or we might suggest that she say, 'I have a right to a turn at bat and insist that you let me have my turn.' If our adolescent says, 'I asked my math teacher to help with a problem and he said that I should already know how to do it and that he did not have time to help me,' we might suggest that she go back to the teacher and say, 'Maybe I should know how to do this problem, but I do not. It is important to me to learn how to work these types of problems and I think that you should help me. When can we arrange a time?' In this situation, the adolescent is asserting her right to receive help from the teacher, and in a firm yet reasonable way. Or if our adolescent wants to use the family car, discuss the issue of her right to the car instead of arguing about family rules. Other rights frequently at issue within families include rights to privacy, including telephone conversations, the sanctity of our rooms or things, rights to express our opinions, right to family resources such as money or food, rights to loving relationships, to who watches what television program, how loud the stereo can be played, and on and on. While children need to learn to respect the rights of others, they also need to learn how to responsibly assert their own rights. To use an old expression, they need to learn to stick up for themselves. The notion of responsibilities is closely related to the idea of rights. As children become aware of their rights, they must also learn that the rights of others need to be assured. A grade schooler has a new puppy and Dad tells the grade schooler that he will be responsible for feeding the puppy. The puppy then has a right to be fed. The adolescent has a right to access to the family car. Other family members have a right to expect that the car will be used with care. If the adolescent respects the rights of other family members and other drivers, he is then a responsible driver. Family members have a right to an orderly home. Each family member, thus, has a responsibility to help keep the house neat. Children learn about responsibilities in part through relationships and seeing other people behave responsibly. In part, children learn to be responsible through active teaching by parents and other adults. Children also learn about responsibility through discussions about the rights of others. Yes, children learn from life experience, but they also need to have the ideas of rights and responsibilities explained and re- explained from a very young age. Are children too young to have responsibilities when they are only two or three years old? This is, in fact, a very good age to learn to respect the rights of others. If emphasis on rights and responsibilities can be initiated at a very young age, it will not be much of a problem as children Teaching children about rights and responsibilities can be overdone. Children can assert their rights so frequently they actually alienate everyone. Similarly, a child may become somewhat compulsive about doing what is right. In either situation, parenting adults have gone too far and should back off a little. The criteria of reasonableness, appropriateness, and effectiveness should govern our involvement with children as we teach them about rights and LEARNING TO THINK INDEPENDENTLY: Teaching children to think independently is one of the most challenging tasks for parenting adults. We are at the heart of a real parenting paradox. We want our children to think independently but we also want them to accept our ideas and values. How can we keep our children on the right track while simultaneously assuring that they become autonomous individuals who think independently? How do children move from being the one who is influenced to being the one who is influencing? How do children make the transition from follower to leader or independent participant? It will happen gradually and spontaneously if we first encourage it to happen and then allow it to happen. Let us make the point through a fairly simple example and then move on to discuss the idea in depth. A six-year-old had grown up in a family where she was allowed to express her ideas, disagree, and dream. Her first- grade teacher encouraged independent thinking and her parents took delight in her imagination, innovative thinking, and developing intellectual agility. Similarly, her teacher liked children who appropriately said what they thought, entered into lively discussions, and showed enthusiasm for finding out about the world. This particular incident happened when it was still customary to start the school day with a prayer: After one such group prayer, teacher said to a six-year-old, 'You did not have your head bowed and your eyes closed during prayer.' Teacher was, of course, trying to encourage the child to conform to customary praying behavior. The child spontaneously responded, 'You must not have had your eyes closed either, or you would not have noticed that I did not have my eyes closed.' How did the teacher handle this? Did she see the reply as smart alecky? No, she saw it was a perceptive conclusion for a six-year-old to have made. She said, 'That's true; why don't we both close our eyes and bow our heads next time?' Three cheers for this teacher. When a child tells us about something that bothers him, he may wait expectantly to see what we think. We can tell him what we think, or we might respond, 'What do you think about that?' If the child says, 'I don't know; what do you think?' we might then say, 'I will tell you what I think but first I want to find out what your ideas are.' This encourages independent thinking and lets the child know that he is both permitted and expected to think independently. Another child comes to us with a problem, wanting to know what she should do. We go through the same process of asking her what she thinks she should do. We say, 'Why don't you think about it for a while; then let's talk.' We are saying, in essence, 'You think independently a while longer and I will think independently about the situation also.' Go back to the child, of course, after a while and ask, 'Have you thought any more about that situation?' This again encourages the child to think independently and renews our permission to think independently. A mild level of skepticism is fundamental to a child's growing capacity to think independently. For instance, a child comes home and tells us that her friend has two ponies and three dogs, when we know that her family does not own land and that they are not boarding animals. We say to the child, 'That is not true.' The child insists it is true. We say, 'I do not think that is true; and it is clear that you and I disagree about whether or not it is true.' That is the end of the conversation. Have we helped the child to think independently? We have pointed out that things are sometimes misunderstood by us or are misrepresented by others. This encourages the child to be a little skeptical about things she is told by others. The same approach can be used with things children read or are told about. It is extremely important that we do not always impose our beliefs and values on our children. The extent to which a child learns to think independently has a lot to do with our willingness to permit independent thought. We further encourage independent thinking by letting him know we feel good about it when he expresses his own ideas, comes to his own conclusions, and thinks independently. At times we need to insist that he think independently by refusing to say what to do or think, making him sit down to think things through himself. We also need to demonstrate independent thinking. Just as our child is permitted to disagree with us, we also have the right to disagree with him. He sees that we come to our own conclusions, and do not always accept what others say. In addition, we point out independent thinking techniques such as considering alternatives, mental rehearsals, and the old standby, 'Think before you act.' Helping children think independently is a real parenting paradox. If we err, it should be on the side of independent thinking. Our child may be a little flippant or rude, but this is more acceptable than risking his becoming mechanical and closed off.
Evolution of the horse The evolution of the horse occurred over a period of 50 million years, transforming the small, dog-sized, forest-dwelling Eohippus into the modern horse. Paleozoologists have been able to piece together a more complete outline of the modern horse's evolutionary lineage than that of any other animal. The horse belongs to the order Perissodactyla (odd-toed ungulates), the members of which all share hooved feet and an odd number of toes on each foot, as well as mobile upper lips and a similar tooth structure. This means that horses share a common ancestry with tapirs and rhinoceroses. The perissodactyls arose in the late Paleocene, less than 10 million years after the Cretaceous–Paleogene extinction event. This group of animals appears to have been originally specialized for life in tropical forests, but whereas tapirs and, to some extent, rhinoceroses, retained their jungle specializations, modern horses are adapted to life on drier land, in the much-harsher climatic conditions of the steppes. Other species of Equus are adapted to a variety of intermediate conditions. The early ancestors of the modern horse walked on several spread-out toes, an accommodation to life spent walking on the soft, moist grounds of primeval forests. As grass species began to appear and flourish, the equids' diets shifted from foliage to grasses, leading to larger and more durable teeth. At the same time, as the steppes began to appear, the horse's predecessors needed to be capable of greater speeds to outrun predators. This was attained through the lengthening of limbs and the lifting of some toes from the ground in such a way that the weight of the body was gradually placed on one of the longest toes, the third. - 1 History of research - 2 Before Odd-toed ungulates - 3 Eocene and Oligocene: early equids - 4 Miocene and Pliocene: true equines - 5 Modern horses - 6 Details - 7 See also - 8 Further reading - 9 References - 10 External links History of research Indigenous modern horses died out in the New World at the end of the Pleistocene, about 12,000 years ago, and thus were absent until the Spanish brought domestic horses from Europe, beginning in 1493. Escaped horses quickly established large wild herds. In the 1760s, the early naturalist Buffon suggested this was an indication of inferiority of the New World fauna, but later reconsidered this idea. William Clark's 1807 expedition to Big Bone Lick found "leg and foot bones of the Horses", which were included with other fossils sent to Thomas Jefferson and evaluated by the anatomist Caspar Wistar, but neither commented on the significance of this find. The first equid fossil was found in the gypsum quarries in Montmartre, Paris in the 1820s. The tooth was sent to the Paris Conservatory, where it was identified by Georges Cuvier, who identified it as a browsing equine related to the tapir. His sketch of the entire animal matched later skeletons found at the site. During the Beagle survey expedition, the young naturalist Charles Darwin had remarkable success with fossil hunting in Patagonia. On 10 October 1833 at Santa Fe, Argentina, he was "filled with astonishment" when he found a horse's tooth in the same stratum as fossil giant armadillos, and wondered if it might have been washed down from a later layer, but concluded this was "not very probable". After the expedition returned in 1836, the anatomist Richard Owen confirmed the tooth was from an extinct species, which he subsequently named Equus curvidens, and remarked, "This evidence of the former existence of a genus, which, as regards South America, had become extinct, and has a second time been introduced into that Continent, is not one of the least interesting fruits of Mr. Darwin's palæontological discoveries." In 1848, a study On the fossil horses of America by Joseph Leidy systematically examined Pleistocene horse fossils from various collections, including that of the Academy of Natural Sciences and concluded at least two ancient horse species had existed in North America: Equus curvidens and another, which he named Equus americanus. A decade later, however, he found the latter name had already been taken and renamed it Equus complicatus. In the same year, he visited Europe and was introduced by Owen to Darwin. The original sequence of species believed to have evolved into the horse was based on fossils discovered in North America in the 1870s by paleontologist Othniel Charles Marsh. The sequence, from Eohippus to the modern horse (Equus), was popularized by Thomas Huxley and became one of the most widely known examples of a clear evolutionary progression. The horse's evolutionary lineage became a common feature of biology textbooks, and the sequence of transitional fossils was assembled by the American Museum of Natural History into an exhibit that emphasized the gradual, "straight-line" evolution of the horse. Since then, as the number of equid fossils has increased, the actual evolutionary progression from Eohippus to Equus has been discovered to be much more complex and multibranched than was initially supposed. The straight, direct progression from the former to the latter has been replaced by a more elaborate model with numerous branches in different directions, of which the modern horse is only one of many. George Gaylord Simpson in 1951 first recognized the modern horse was not the "goal" of the entire lineage of equids, it is simply the only genus of the many horse lineages to survive. Detailed fossil information on the rate and distribution of new equid species has also revealed that the progression between species was not as smooth and consistent as was once believed. Although some transitions, such as that of Dinohippus to Equus, were indeed gradual progressions, a number of others, such as that of Epihippus to Mesohippus, were relatively abrupt in geologic time, taking place over only a few million years. Both anagenesis (gradual change in an entire population's gene frequency) and cladogenesis (a population "splitting" into two distinct evolutionary branches) occurred, and many species coexisted with "ancestor" species at various times. The change in equids' traits was also not always a "straight line" from Eohippus to Equus: some traits reversed themselves at various points in the evolution of new equid species, such as size and the presence of facial fossae, and only in retrospect can certain evolutionary trends be recognized. Before Odd-toed ungulates Phenacodontidae is the earliest family in the order condylarthra which is believed to be the ancestor to all odd-toed ungulates. It contains the genera Almogaver, Copecion, Ectocion, Eodesmatodon, Meniscotherium, Ordathspidotherium, Phenacodus and Pleuraspidotherium. The family lived from the Early Paleocene to the Middle Eocene in Europe and were about the size of a sheep, with tails making slightly less than half of the length of their bodies and unlike their ancestors, good running skills for eluding predators. Eocene and Oligocene: early equids Eohippus appeared in the Ypresian (early Eocene), about 52 mya (million years ago). It was an animal approximately the size of a fox (250–450 mm in height), with a relatively short head and neck and a springy, arched back. It had 44 low-crowned teeth, in the typical arrangement of an omnivorous, browsing mammal: three incisors, one canine, four premolars, and three molars on each side of the jaw. Its molars were uneven, dull, and bumpy, and used primarily for grinding foliage. The cusps of the molars were slightly connected in low crests. Eohippus browsed on soft foliage and fruit, probably scampering between thickets in the mode of a modern muntjac. It had a small brain, and possessed especially small frontal lobes. Its limbs were decently long relative to its body, already showing the beginnings of adaptations for running. However, all of the major leg bones were unfused, leaving the legs flexible and rotatable. Its wrist and hock joints were low to the ground. The forelimbs had developed five toes, of which four were equipped with small proto-hooves; the large fifth "toe-thumb" was off the ground. The hind limbs had small hooves on three out of the five toes, while the vestigial first and fifth toes did not touch the ground. Its feet were padded, much like a dog's, but with the small hooves in place of claws. For a span of about 20 million years, Eohippus thrived with few significant evolutionary changes. The most significant change was in the teeth, which began to adapt to its changing diet, as these early Equidae shifted from a mixed diet of fruits and foliage to one focused increasingly on browsing foods. During the Eocene, an Eohippus species (most likely Eohippus angustidens) branched out into various new types of Equidae. Thousands of complete, fossilized skeletons of these animals have been found in the Eocene layers of North American strata, mainly in the Wind River basin in Wyoming. Similar fossils have also been discovered in Europe, such as Propalaeotherium (which is not considered ancestral to the modern horse). Approximately 50 million years ago, in the early-to-middle Eocene, Eohippus smoothly transitioned into Orohippus through a gradual series of changes. Although its name means "mountain horse", Orohippus was not a true horse and did not live in the mountains. It resembled Eohippus in size, but had a slimmer body, an elongated head, slimmer forelimbs, and longer hind legs, all of which are characteristics of a good jumper. Although Orohippus was still pad-footed, the vestigial outer toes of Eohippus were not present in the Orohippus; there were four toes on each fore leg, and three on each hind leg. The most dramatic change between Eohippus and Orohippus was in the teeth: the first of the premolar teeth were dwarfed, the last premolar shifted in shape and function into a molar, and the crests on the teeth became more pronounced. Both of these factors gave the teeth of Orohippus greater grinding ability, suggesting Orohippus ate tougher plant material. In the mid-Eocene, about 47 million years ago, Epihippus, a genus which continued the evolutionary trend of increasingly efficient grinding teeth, evolved from Orohippus. Epihippus had five grinding, low-crowned cheek teeth with well-formed crests. A late species of Epihippus, sometimes referred to as Duchesnehippus intermedius, had teeth similar to Oligocene equids, although slightly less developed. Whether Duchesnehippus was a subgenus of Epihippus or a distinct genus is disputed. Epihippus was only 2 feet tall. In the late Eocene and the early stages of the Oligocene epoch (32–24 mya), the climate of North America became drier, and the earliest grasses began to evolve. The forests were yielding to flatlands, home to grasses and various kinds of brush. In a few areas, these plains were covered in sand, creating the type of environment resembling the present-day prairies. In response to the changing environment, the then-living species of Equidae also began to change. In the late Eocene, they began developing tougher teeth and becoming slightly larger and leggier, allowing for faster running speeds in open areas, and thus for evading predators in nonwooded areas. About 40 mya, Mesohippus ("middle horse") suddenly developed in response to strong new selective pressures to adapt, beginning with the species Mesohippus celer and soon followed by Mesohippus westoni. In the early Oligocene, Mesohippus was one of the more widespread mammals in North America. It walked on three toes on each of its front and hind feet (the first and fifth toes remained, but were small and not used in walking). The third toe was stronger than the outer ones, and thus more weighted; the fourth front toe was diminished to a vestigial nub. Judging by its longer and slimmer limbs, Mesohippus was an agile animal. Mesohippus was slightly larger than Epihippus, about 610 mm (24") at the shoulder. Its back was less arched, and its face, snout, and neck were somewhat longer. It had significantly larger cerebral hemispheres, and had a small, shallow depression on its skull called a fossa, which in modern horses is quite detailed. The fossa serves as a useful marker for identifying an equine fossil's species. Mesohippus had six grinding "cheek teeth", with a single premolar in front—a trait all descendant Equidae would retain. Mesohippus also had the sharp tooth crests of Epihippus, improving its ability to grind down tough vegetation. Around 36 million years ago, soon after the development of Mesohippus, Miohippus ("lesser horse") emerged, the earliest species being Miohippus assiniboiensis. As with Mesohippus, the appearance of Miohippus was relatively abrupt, though a few transitional fossils linking the two genera have been found. Mesohippus was once believed to have anagenetically evolved into Miohippus by a gradual series of progressions, but new evidence has shown its evolution was cladogenetic: a Miohippus population split off from the main Mesohippus genus, coexisted with Mesohippus for around four million years, and then over time came to replace Mesohippus. Miohippus was significantly larger than its predecessors, and its ankle joints had subtly changed. Its facial fossa was larger and deeper, and it also began to show a variable extra crest in its upper cheek teeth, a trait that became a characteristic feature of equine teeth. Miohippus ushered in a major new period of diversification in Equidae. While Mesohippus died out in the mid-Oligocene, Miohippus continued to thrive, and in the early Miocene (24–5.3 mya), it began to rapidly diversify and speciate. It branched out into two major groups, one of which adjusted to the life in forests once again, while the other remained suited to life on the prairies. Miocene and Pliocene: true equines The forest-suited form was Kalobatippus (or Miohippus intermedius, depending on whether it was a new genus or species), whose second and fourth front toes were long, well-suited travel on the soft forest floors. Kalobatippus probably gave rise to Anchitherium, which travelled to Asia via the Bering Strait land bridge, and from there to Europe. In both North America and Eurasia, larger-bodied genera evolved from Anchitherium: Sinohippus in Eurasia and Hypohippus and Megahippus in North America. Hypohippus became extinct by the late Miocene. The Miohippus population that remained on the steppes is believed to be ancestral to Parahippus, a North American animal about the size of a small pony, with a prolonged skull and a facial structure resembling the horses of today. Its third toe was stronger and larger, and carried the main weight of the body. Its four premolars resembled the molar teeth and the first were small and almost nonexistent. The incisor teeth of Parahippus, like those of its predecessors, had a crown as humans do; however, the top incisors had a trace of a shallow crease marking the beginning of the core/cup. In the middle of the Miocene epoch, the grazer Merychippus flourished. It had wider molars than its predecessors, which are believed to have been used for crunching the hard grasses of the steppes. The hind legs, which were relatively short, had side toes equipped with small hooves, but they probably only touched the ground when running. Merychippus radiated into at least 19 additional grassland species. Three lineages within Equidae are believed to be descended from the numerous varieties of Merychippus: Hipparion, Protohippus and Pliohippus. The most different from Merychippus was Hipparion, mainly in the structure of tooth enamel: in comparison with other Equidae, the inside, or tongue side, had a completely isolated parapet. A complete and well-preserved skeleton of the North American Hipparion shows an animal the size of a small pony. They were very slim, rather like antelopes, and were adapted to life on dry prairies. On its slim legs, Hipparion had three toes equipped with small hooves, but the side toes did not touch the ground. In North America, Hipparion and its relatives (Cormohipparion, Nannippus, Neohipparion, and Pseudhipparion), proliferated into many kinds of equids, at least one of which managed to migrate to Asia and Europe during the Miocene epoch. (European Hipparion differs from American Hipparion in its smaller body size – the best-known discovery of these fossils was near Athens.) Pliohippus arose from Callippus in the middle Miocene, around 12 mya. It was very similar in appearance to Equus, though it had two long extra toes on both sides of the hoof, externally barely visible as callused stubs. The long and slim limbs of Pliohippus reveal a quick-footed steppe animal. Until recently, Pliohippus was believed to be the ancestor of present-day horses because of its many anatomical similarities. However, though Pliohippus was clearly a close relative of Equus, its skull had deep facial fossae, whereas Equus had no fossae at all. Additionally, its teeth were strongly curved, unlike the very straight teeth of modern horses. Consequently, it is unlikely to be the ancestor of the modern horse; instead, it is a likely candidate for the ancestor of Astrohippus. Plesippus is often considered an intermediate stage between Dinohippus and the extant genus, Equus. The famous fossils found near Hagerman, Idaho were originally thought to be a part of the genus Plesippus. Hagerman Fossil Beds (Idaho) is a Pliocene site, dating to about 3.5 mya. The fossilized remains were originally called Plesippus shoshonensis, but further study by paleontologists determined the fossils represented the oldest remains of the genus Equus. Their estimated average weight was 425 kg, roughly the size of an Arabian horse. At the end of the Pliocene, the climate in North America began to cool significantly and most of the animals were forced to move south. One population of Plesippus moved across the Bering land bridge into Eurasia around 2.5 mya. The genus Equus, which includes all extant equines, is believed to have evolved from Dinohippus, via the intermediate form Plesippus. One of the oldest species is Equus simplicidens, described as zebra-like with a donkey-shaped head. The oldest material to date is ~3.5 million years old from Idaho, USA. The genus appears to have spread quickly into the Old World, with the similarly aged Equus livenzovensis documented from western Europe and Russia. Molecular phylogenies indicate the most recent common ancestor of all modern equids (members of the genus Equus) lived ~5.6 (3.9-7.8) mya. Direct paleogenomic sequencing of a 700,000 year-old middle Pleistocene horse metapodial bone from Canada implies a more recent 4.07 Myr before present date for the most recent common ancestor (MRCA) within the range of 4.0 to 4.5 Myr BP. The oldest divergencies are the Asian hemiones (subgenus E. (Asinus)), including the kulan, onager, and kiang), followed by the African zebras (subgenera E. (Dolichohippus), and E. (Hippotigris)). All other modern forms including the domesticated horse (and many fossil Pliocene and Pleistocene forms) belong to the subgenus E. (Equus) which diverged ~4.8 (3.2-6.5) million years ago. Pleistocene horse fossils have been assigned to a multitude of species, with over 50 species of equines described from the Pleistocene of North America alone, although the taxonomic validity of most of these has been called into question. Recent genetic work on fossils has found evidence for only three genetically divergent equid lineages in Pleistocene North and South America. These results suggest all North American fossils of caballine-type horses (which also include the domesticated horse and Przewalski's horse of Europe and Asia), as well as South American fossils traditionally placed in the subgenus E. (Amerhippus) belong to the same species: E. ferus. Remains attributed to a variety of species and lumped as New World stilt-legged horses (including E. francisci, E. tau, E. quinni and potentially North American Pleistocene fossils previously attributed to E. cf. hemiones, and E. (Asinus) cf. kiang) probably all belong to a second species endemic to North America, which despite a superficial resemblance to species in the subgenus E. (Asinus) (and hence occasionally referred to as North American ass) is closely related to E. ferus. Surprisingly, the third species, endemic to South America, and traditionally referred to as Hippidion, originally believed to be descended from Pliohippus, was shown to be a third species in the genus Equus, closely related to the New World stilt-legged horse. The temporal and regional variation in body size and morphological features within each lineage indicates extraordinary intraspecific plasticity. Such environment-driven adaptative changes would explain why the taxonomic diversity of Pleistocene equids has been overestimated on morphoanatomical grounds. According to these results, it appears the genus Equus evolved from a Dinohippus-like ancestor ~4-7 mya. It rapidly spread into the Old World and there diversified into the various species of asses and zebras. A North American lineage of the subgenus E. (Equus) evolved into the New World stilt-legged horse (NWSLH). Subsequently, populations of this species entered South America as part of the Great American Interchange shortly after the formation of the Isthmus of Panama, and evolved into the form currently referred to as "Hippidion" ~2.5 million years ago. Hippidion is thus unrelated to the morphologically similar Pliohippus, which presumably went extinct during the Miocene. Both the NWSLH and Hippidium show adaptations to dry, barren ground, whereas the shortened legs of Hippidion may have been a response to sloped terrain. In contrast, the geographic origin of the closely related modern E. ferus is not resolved. However, genetic results on extant and fossil material of Pleistocene age indicate two clades, potentially subspecies, one of which had a holarctic distribution spanning from Europe through Asia and across North America and would become the founding stock of the modern domesticated horse. The other population appears to have been restricted to North America. One or more North American populations of E. ferus entered South America ~1.0-1.5 million years ago, leading to the forms currently known as "E. (Amerhippus)", which represent an extinct geographic variant or race of E. ferus, however. In June 2013, a group of researchers announced that they had sequenced the DNA of a 560–780 thousand year old horse, using material extracted from a leg bone found buried in permafrost in Canada's Yukon territory. Prior to this publication, the oldest nuclear genome that had been successfully sequenced was dated at 110–130 thousand years ago. For comparison, the researchers also sequenced the genomes of a 43,000 year old Pleistocene horse, a Przewalski's horse, five modern horse breeds, and a donkey. Analysis of differences between these genomes indicated that the last common ancestor of modern horses, donkeys, and zebras existed 4 to 4.5 million years ago. The results also indicated that Przewalski’s horse diverged from other modern types of horse about 43,000 years ago, and had never in its evolutionary history been domesticated. Digs in western Canada have unearthed clear evidence horses existed in North America until about 12,000 years ago. However, all Equidae in North America ultimately became extinct. The causes of this extinction (simultaneous with the extinctions of a variety of other American megafauna) have been a matter of debate. Given the suddenness of the event and because these mammals had been flourishing for millions of years previously, something quite unusual must have happened. The first main hypothesis attributes extinction to climate change. For example, in Alaska, beginning approximately 12,500 years ago, the grasses characteristic of a steppe ecosystem gave way to shrub tundra, which was covered with unpalatable plants. The other hypothesis suggests extinction was linked to overexploitation of naive prey by newly arrived humans. The extinctions were roughly simultaneous with the end of the most recent glacial advance and the appearance of the big game-hunting Clovis culture. Several studies have indicated humans probably arrived in Alaska at the same time or shortly before the local extinction of horses. Additionally, it has been proposed that the steppe-tundra vegetation transition in Beringia may have been a consequence, rather than a cause, of the extinction of megafaunal grazers. In Eurasia, horse fossils began occurring frequently again in archaeological sites in Kazakhstan and the southern Ukraine about 6,000 years ago. From then on, domesticated horses, as well as the knowledge of capturing, taming, and rearing horses, probably spread relatively quickly, with wild mares from several wild populations being incorporated en route. Return to the Americas Horses only returned to the Americas with Christopher Columbus in 1493. These were Iberian horses first brought to Hispaniola and later to Panama, Mexico, Brazil, Peru, Argentina, and, in 1538, Florida. The first horses to return to the main continent were 16 specifically identified horses brought by Hernán Cortés. Subsequent explorers, such as Coronado and De Soto brought ever-larger numbers, some from Spain and others from breeding establishments set up by the Spanish in the Caribbean. Later, as Spanish missions were founded on the mainland, horses would eventually be lost or stolen, and proliferated into large herds of feral horses that became known as mustangs. The indigenous peoples of the Americas did not have a specific word for horses, and came to refer to them in various languages as a type of dog or deer (in one case, "elk-dog", in other cases "big dog" or "seven dogs", referring to the weight each animal could pull). The ancestors of the horse came to walk only on the end of the third toe and both side toes. Skeletal remnants show obvious wear on the back of both sides of metacarpal and metatarsal bones, commonly called the “splint bones”. They are the remnants of the second and the fourth toe. Modern horses retain the splint bones; they are often believed to be useless attachments, but they in fact play an important role in supporting the carpal joints (front knees) and even the tarsal joints (hocks). Throughout the phylogenetic development, the teeth of the horse underwent significant changes. The type of the original omnivorous teeth with short, "bumpy" molars, with which the prime members of the evolutionary line distinguished themselves, gradually changed into the teeth common to herbivorous mammals. They became long (as much as 100 mm), roughly cubical molars equipped with flat grinding surfaces. In conjunction with the teeth, during the horse’s evolution, the elongation of the facial part of the skull is apparent, and can also be observed in the backward-set eyeholes. In addition, the relatively short neck of the equine ancestors became longer, with equal elongation of the legs. Finally, the size of the body grew as well. The ancestral coat color of E. ferus was probably a uniform dun, consistent with modern populations of Przewalski's horses. Pre-domestication variants including black and spotted have been inferred from cave wall paintings and confirmed by genomic analysis. - MacFadden, Bruce J (2003 digitization of 1999 reprint). Fossil Horses: Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge & New York: Cambridge University Press. ISBN 0-521-47708-5. Retrieved 6 June 2010. - Legendre, Serge (1989). Les communautés de mammifères du Paléogène (Eocène supérieur et Oligocène) d'Europe occidentale : structures, milieux et évolution. München: F. Pfeil. p. 110. ISBN 978-3-923871-35-3. - Academy of Natural Sciences - Joseph Leidy - American Horses - Academy of Natural Sciences - Thomas Jefferson Fossil Collection - Ancient Horse Fossils - Horse breeding and management, James Warren Evans 1992 - Knell, Simon J.; Suzanne Macleod; Sheila E. R. 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"Systematics and phylogeny of Hipparion, Neohipparion, Nannippus, and Cormohipparion (Mammalia, Equidae) from the Miocene and Pliocene of the New World". Bulletin of the American Museum of Natural History 179 (1): 1–195. - MacFadden, B. J. (1984). "Astrohippus and Dinohippus". J. Vert. Paleon 4 (2): 273–283. doi:10.1080/02724634.1984.10012009. - Jens Lorenz Franzen: Die Urpferde der Morgenröte. Elsevier, Spektrum Akademischer Verlag, München 2007, ISBN 3-8274-1680-9 - Azzaroli, A. (1992). "Ascent and decline of monodactyl equids: a case for prehistoric overkill". Ann. Zool. Finnici 28: 151–163. - Ludovic Orlando, Aurélien Ginolhac, Guojie Zhang, et al. (2013). "Recalibrating Equus evolution using the genome sequence of an early Middle Pleistocene horse". Nature 499 (7456): 74–8. doi:10.1038/nature12323. PMID 23803765. - Weinstock, J.; et al. (2005). "Evolution, systematics, and phylogeography of Pleistocene horses in the New World: a molecular perspective". PLoS Biology 3 (8): e241. doi:10.1371/journal.pbio.0030241. PMC 1159165. PMID 15974804. Retrieved 2008-12-19. - Azzaroli, A. (1998). "The genus Equus in North America". PalaeontographItal 85: 1–60. - Orlando, L.; et al. (2008). "Ancient DNA Clarifies the Evolutionary History of American Late Pleistocene Equids". Journal of Molecular Evolution 66 (5): 533–538. doi:10.1007/s00239-008-9100-x. PMID 18398561. - Vila, C.; et al. (2001). "Widespread Origins of Domestic Horse Lineages" (PDF). Science 291 (5503): 474–7. doi:10.1126/science.291.5503.474. PMID 11161199. Retrieved 2008-12-19. - Jansen, T.; et al. (July 2002). "Mitochondrial DNA and the origins of the domestic horse". Proceedings of the National Academy of Sciences 99 (16): 10905–10910. doi:10.1073/pnas.152330099. PMC 125071. PMID 12130666. Retrieved 2008-12-19. - Erika Check Hayden (26 June 2013). "First horses arose 4 million years ago". Nature. doi:10.1038/nature.2013.13261. - Jane J Lee (26 June 2013). "World's Oldest Genome Sequenced From 700,000-Year-Old Horse DNA". National Geographic. - Singer, Ben (May 2005). A brief history of the horse in America. Canadian Geographic Magazine. Retrieved 16 October 2009. - LeQuire, Elise (2004-01-04). "No Grass, No Horse". The Horse, online edition. Retrieved 2009-06-08. - Guthrie, R. D. (2003-11-13). "Rapid body size decline in Alaskan Pleistocene horses before extinction". Nature 426 (6963): 169–171. doi:10.1038/nature02098. PMID 14614503. Retrieved 2010-12-30. - "Ice Age Horses May Have Been Killed Off by Humans" National Geographic News, May 1, 2006. - Buck, Caitlin E.; Bard, Edouard (2007). "A calendar chronology for Pleistocene mammoth and horse extinction in North America based on Bayesian radiocarbon calibration". Quaternary Science Reviews 26 (17–18): 2031. doi:10.1016/j.quascirev.2007.06.013. - Solow, Andrew; Roberts, David; Robbirt, Karen (May 9, 2006). "On the Pleistocene extinctions of Alaskan mammoths and horses". In Haynes, C. Vance. Proceedings of the National Academy of Sciences of the United States of America (19 ed.) (Proceedings of the National Academy of Sciences of the United States of America) 103 (19): 7351–3. doi:10.1073/pnas.0509480103. PMC 1464344. PMID 16651534. - Guthrie, R. D. (2006-05-11). "New carbon dates link climatic change with human colonization and Pleistocene extinctions". Nature 441 (7090): 207–209. doi:10.1038/nature04604. PMID 16688174. Retrieved 2010-12-30. - Zimov, S. A.; Chuprynin, V. I.; Oreshko, A. P.; Chapin, F. S.; Reynolds, J. F.; Chapin, M. C. (Nov 1995). "Steppe-tundra transition: a herbivore-driven biome shift at the end of the Pleistocene". The American Naturalist 146 (5): 765–794. doi:10.1086/285824. JSTOR 2462990. - Warmuth, V.; Eriksson, A.; Bower, M. A.; Barker, G.; Barrett, E.; Hanks, B. K.; Li, S.; Lomitashvili, D.; Ochir-Goryaeva, M.; Sizonov, G. V.; Soyonov, V.; Manica, A. (2012-05-07). "Reconstructing the origin and spread of horse domestication in the Eurasian steppe". Proceedings of the National Academy of Sciences 109 (21): 8202. doi:10.1073/pnas.1111122109. Retrieved 2012-05-08. - Luís, Cristina; et al. (2006). "Iberian Origins of New World Horse Breeds". Journal of Heredity 97 (2): 107–113. doi:10.1093/jhered/esj020. PMID 16489143. - Pruvost, M.; et al. (November 2011). "Genotypes of predomestic horses match phenotypes painted in Paleolithic works of cave art". Proceedings of the National Academy of Sciences 108 (46): 18626–18630. doi:10.1073/pnas.1108982108. - Horse Evolution Over 55 Million Years. Tufts University. January 10, 1998. Retrieved July 11, 2007.: An excerpted collection of images of horse fossils - Evolution of Horses
LESSON: Circumference of Circles - Identify ratio of circumference to diameter as pi. - Find the circumference of circles given diameter or radius. - Find diameter or radius of circles given circumference. - Solve real world problems involving circumference of circles. - the measure of the distance around the outside edge of a circle. - the measure of the distance across the center of a circle. - the measure of the distance half-way across the circle. It is the measure from the center to the outer edge. The radius is also half the length of the diameter. - the ratio of the diameter to the circumference, 3.14 - a Greek mathematician and philosopher who identified 3.14 as pi. READ: Identify Ratio of Circumference to Diameter as Pi Identify Ratio of Circumference to Diameter as Pi To work with circles, we first need to review the parts of a circle. Let’s begin there. We can measure several key parts of a circle. We can measure the distance across the center of the circle. This distance is called the diameter of the circle. Here is a picture of the diameter. We can measure the distance from the center of the circle to the outer edge. This distance is called the radius. Notice that the radius is one-half of the measure of the diameter. Here is a picture of the radius. We can measure the distance around the outer edge of the circle too. This distance is called the circumference of the circle. The circumference of the circle is the perimeter of the circle, only with circles we don’t call it perimeter we call the measure around the outside edge of the circle the circumference. To understand things about circles, let’s consider some history. Back in the time when the Greeks were discovering all sorts of things about mathematics, they were puzzled by mathematics and by the relationships between different measurements and geometry. The Greeks were famous for investigating ratios and proportions. When they studied different things, they knew that there was a connection between shapes and their measurements. Some of the Greeks thought a lot about circles. Although the Babylonians had been investigating circles too, it was a Greek man named Archimedes who is credited with figuring out that there is a relationship between the distance across the circle or the diameter of the circle and the distance around the edge of the circle or the circumference of the circle. Archimedes discovered that if you take the distance across the circle and stretch it around the circumference, that the length of the diameter will go around the circle 3 and a bit more times. Let’s say that the diameter of this circle is 5 cm, well the circumference of the circle is three and a little more times the 5 cm. Because of that, we say that the ratio of the diameter to the circumference is pi. We use the number 3.14 for pi because the ratio is a terminating decimal and does not end. However we use two decimal places for pi works for figuring out the circumference of the circle. Here is the symbol for pi. When you see this symbol, you can use 3.14 in your arithmetic. Think about what you have learned and answer these questions. - Who was the first person to figure out the relationship between the diameter and the circumference? - What is the distance across the circle called? - What is the distance around the circle called?
We may already know the series of Power Supply Unit (PSU) on a computer, which is a rectangular box inside the CPU and is above the power jack. What is a Power Supply? Understanding Computer Power Supply Power Supply is a computer hardware that plays a role in supplying voltage to each computer component that requires an electric current. In addition, the Power Supply can also change the electric current from AC to DC before passing it on to other computer hardware. Some components such as Motherboard, CD ROM, Hard Drive, Floppy Disk, and others are some examples of devices that receive electricity from the Power Supply. As for the amount of electricity that can be flowed, it follows the needs of each hardware and is calculated based on Watts. Well, for the amount of Power Supply around 150 – 350 Watts. How does a power supply work? How a Computer Power Supply Works The working principle of the Power Supply is in charge of checking through an electric current test before it reaches the computer system. When successful and shows a positive signal (Power Good) it will be forwarded to the mainboard as a sign that the computer system is ready to operate. After all, the Power Supply will distribute the power according to the capacity required by each computer component. Apart from that all Power Supply also plays a role in keeping the electric current stable on every computer component. What is the function of the Power Supply? Computer Power Supply Functions The function of the Power Supply is to supply the electric current to each component contained in the computer. In addition, the main function of the computer’s Power Supply is to change the Alternating Current (AC) voltage to Direct Current (DC) before it is distributed to all computer components. Therefore, if the Power Supply does not work properly it can cause the DC voltage to become unstable which results in damage to other components such as hard drives and so on. At first glance we have discussed what are the uses of a power supply on a computer, now we will discuss the types of computer power supply circuits. What are the types of Power Supply? Types of Computer Power Supplies In general, there are two types of power supplies based on their functions or uses, each of which has its advantages and disadvantages. Power Supply AT The first power supply that was often used for ancient computer or PC models, usually this PSU was found on Pentium II and III computers made in 1997. Well, for current computer models this Power Supply is no longer used. As for the characteristics of the AT Power Supply you can see below. Power Supplay AT characteristics - Has Power below 250 Watts. - Manual Power (On / Off) button. - 8-12 Output terminals connected to the motherboard. In addition, the AT Power Supply has 2 power connectors P8 and P9 which are connected to the motherboard with a black cable. ATX Power Supply The latest type of Power Supplay than before which has the ability to be more efficient in processing incoming electric current with a better design. This ATX power supply is often used on the latest computers, where its use is quite practical because it supports the operational system through software. Users can turn on and turn off the computer without the need to press the Power button on the PSU again. - ATX Power Supply Features - Requires more power. - The Power (On / Off) button has been integrated into the system so when the computer shuts down the PSU also shuts down. - Output terminals numbered 20-24 which are connected to the motherboard. - There is an additional SATA Power connector. Some of the differences in the AT and ATX Power Supply above are quite significant, even though the main function of the Power Supply is still the same. Next, we will discuss the parts of the Power Supply and their uses. Power Supply Components and Their Functions In the Power Supply device, there are several supporting components that have their respective roles and duties, along with an explanation. IC regulator has a main function in keeping the voltage on the circuit of computer components stable. Resistor functions to regulate the voltage on the Power Supply device both lowering and dividing it to limit the incoming electric current so that the motherboard components remain controlled. The diode in the Power Supply device functions to drain the forward voltage current and inhibits the reverse voltage current. Transformers or transformers function to transfer electrical power to two or more electrical circuits through the electromagnetic induction process. The filter functions to equalize the current signal that comes out of the Rectifier. This component is composed of electrolytic capacitors. Actually there are many other supporting components that can support the main performance or function of the computer power supply. Another interesting article about the definition and function of a computer processor and how it works in full. Apart from that, in general, the Power Supply is divided into two types based on the design, namely: Internal Power Supply is a Power Supply that has been arranged and connected to the Motherboard or becomes a unit in the device. For example, on the TV and Amplifier and DVD Player. External Power Supply is a Power Supply which is composed separately from the Motherboard of the device. For example, on cellphone and laptop chargers. From the review of the meaning of Power Supply and its function, we can draw the conclusion that this PSU has a vital role in maintaining the stability of the electric current voltage. A complete discussion of the meaning and function as well as how it works to the types of Power Supply Units (PSUs) can add insight into getting to know more about computer or PC hardware.
Triangles are everywhere and learning how to measure them is helpful in the everyday world. Use the Pythagorean theorem to measure the height of right triangles. If you have a triangle with all sides equal (equilateral triangle), or an isosceles triangle (two sides equal), then divide it into half vertically to get two right triangles. Use the method suited to the information given. - Skill level: Other People Are Reading Things you need Draw a straight line from the highest point of the triangle to the base. Apply the Pythagorean theorem: the square on the hypotenuse is equal to the sum of the squares on the other two sides. As an equation it is written as: c^2=a^2+b^2. Per convention, the hypotenuse is labelled "c," and the two sides are called "a" and "b." Solve for "a": a^2=c^2-b^2, or "b": b^2=c^2-a^2. Input the information you have. For example, let "b" = the line drawn from the top to the base, let "c" = 10cm and "a" = 6cm. Then: b^2=10^2-6^2 b^2=100-36 b^2=64 Find the square root of "b": √b=8. We need to find the square root because we are looking for the length of one side. Write down Heron's formula: a=√p(pa)(p-b)(pc) where "p" is the half perimeter: a+b+c/2. Find the value of "p." For example, let us take the sides to measure 4cm, 5cm and 6cm, with the base being 4cm. Then: p=4+5+6/2 p=15/2 p=7.5 Plug in the value of "p" in the formula. a=√7.5(7.5-4)(7.5-5)(7.5-6) a=√7.5(3.5)(2.5)(1.5) a=√98.4375 a=9.9216 Rewrite the area formula to solve for height: a=1/2bh. So h=2a/b. Plug in the value of area in the formula. h=2*9.9216/4 h=19.8432/4 h=4.9068 - 20 of the funniest online reviews ever - 14 Biggest lies people tell in online dating sites - Hilarious things Google thinks you're trying to search for
Spitzer Catches Young Stars in Their Baby Blanket of Dust Newborn stars peek out from beneath their natal blanket of dust in this dynamic image of the Rho Ophiuchi dark cloud from NASA's Spitzer Space Telescope. Called "Rho Oph" by astronomers, it's one of the closest star-forming regions to our own solar system. Located near the constellations Scorpius and Ophiuchus, the nebula is about 407 light years away from Earth. Rho Oph is made up of a large main cloud of molecular hydrogen, a key molecule allowing new stars to form out of cold cosmic gas, with two long streamers trailing off in different directions. Recent studies using the latest X-ray and infrared observations reveal more than 300 young stellar objects within the large central cloud. Their median age is only 300,000 years, very young compared to some of the universe's oldest stars, which are more than 12 billion years old. "Rho Oph is a favorite region for astronomers studying star formation. Because the stars are so young, we can observe them at a very early evolutionary stage, and because the Ophiuchus molecular cloud is relatively close, we can resolve more detail than in more distant clusters, like Orion," said Lori Allen, lead investigator of the new observations, from the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. This false-color image of Rho Oph's main cloud, Lynds 1688, was created with data from Spitzer's infrared array camera, which has the highest spatial resolution of Spitzer's three imaging instruments, and its multiband imaging photometer, best for detecting cooler materials. The colors in this image reflect the relative temperatures and evolutionary states of the various stars. The youngest stars are surrounded by dusty disks of gas from which they and their potential planetary systems are forming. These young disk systems show up as red in this image. Some of these young stellar objects are surrounded by their own compact nebulae. More evolved stars, which have shed their natal material, are blue. The extended white nebula in the center right of the image is a region of the cloud glowing in infrared light due to the heating of dust by bright young stars near the cloud's right edge. Fainter, multi-hued diffuse emission fills the image. The color of the nebulosity depends on the temperature, composition and size of the dust grains. Most of the stars forming now are concentrated in a filament of cold, dense gas that shows up as a dark cloud in the lower center and left side of the image against the bright background of the warm dust. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. Spitzer's infrared array camera was built by NASA's Goddard Space Flight Center, Greenbelt, Md. The instrument's principal investigator is Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics. The multiband imaging photometer for Spitzer was built by Ball Aerospace Corporation, Boulder, Colo.; the University of Arizona; and Boeing North American, Canoga Park, Calif. Its principal investigator is George Rieke of the University of Arizona, Tucson.
Quadrilateral just means "four sides" (quad means four, lateral means side). Any four-sided shape is a Quadrilateral. But the sides have to be straight, and it has to be2-dimensional. Try drawing a quadrilateral, and measure the angles. They should add to 360° There are special types of quadrilateral: Some types are also included in the definition of other types! For example a square, rhombus andrectangle are also parallelograms. See below for more details. Let us look at each type in turn: \|\|means "right angle"\| \|show equal sides\| Also opposite sides are parallel and of equal length. A rhombus is a four-sided shape where all sides have equal length. Also opposite sides are parallel and opposite angles are equal. Another interesting thing is that the diagonals (dashed lines in second figure) meet in the middle at a right angle. In other words they "bisect" (cut in half) each other at right angles. A rhombus is sometimes called a rhomb or a diamond. \|\|means "right angle"\| \|\|show equal sides\| A square has equal sides and every angle is a right angle (90°) Also opposite sides are parallel. A square also fits the definition of a rectangle (all angles are 90°), and a rhombus (all sides are equal length). A parallelogram has opposite sides parallel and equal in length. Also opposite angles are equal (angles "a" are the same, and angles "b" are the same). NOTE: Squares, Rectangles and Rhombuses are all Parallelograms! A trapezoid (called a trapezium in the UK) has a pair of opposite sides parallel. It is called an Isosceles trapezoid if the sides that aren't parallel are equal in length and both angles coming from a parallel side are equal, as shown. And a trapezium (UK: trapezoid) is a quadrilateral with NO parallel sides: \|US:\|\|a pair of parallel sides\|\|NO parallel sides\| \|UK:\|\|NO parallel sides\|\|a pair of parallel sides\| Hey, it looks like a kite. It has two pairs of sides. Each pair is made up of adjacent sides that are equal in length. The angles are equal where the pairs meet. Diagonals (dashed lines) meet at a right angle, and one of the diagonal bisects (cuts equally in half) the other. ... and that's it for the special quadrilaterals. The only regular quadrilateral is a square. So all other quadrilaterals are irregular. This may seem odd, as in daily life we think of a square as not being a rectangle ... but in mathematics it is. Using the chart below you can answer such questions as: Oh Yes! when two sides cross over, you call it a "Complex" or "Self-Intersecting" quadrilateral like these: They still have 4 sides, but two sides cross over. A quadrilateral is a polygon. In fact it is a 4-sided polygon, just like a triangle is a 3-sided polygon, a pentagon is a 5-sided polygon, and so on. Now that you know the different types, you can play with the Interactive Quadrilaterals. A quadrilateral can sometimes be called:
(PhysOrg.com) -- Large bombardments of meteorites approximately four billion years ago could have helped to make the early Earth and Mars more habitable for life by modifying their atmospheres, suggests the results of a paper published today in the journal Geochimica et Cosmochima Acta. When a meteorite enters a planet's atmosphere, extreme heat causes some of the minerals and organic matter on its outer crust to be released as water and carbon dioxide before it breaks up and hits the ground. Researchers suggest the delivery of this water could have made Earth's and Mars' atmospheres wetter. The release of the greenhouse gas carbon dioxide could have trapped more energy from sunlight to make Earth and Mars warm enough to sustain liquid oceans. In the new study, researchers from Imperial College London analysed the remaining mineral and organic content of fifteen fragments of ancient meteorites that had crashed around the world to see how much water vapour and carbon dioxide they would release when subjected to very high temperatures like those that they would experience upon entering the Earth's atmosphere. The researchers used a new technique called pyrolysis-FTIR, which uses electricity to rapidly heat the fragments at a rate of 20,000 degrees Celsius per second, and they then measured the gases released. They found that on average, each meteorite was capable of releasing up to 12 percent of the meteorites' mass as water vapour and 6 percent of the meteorites' mass as carbon dioxide when entering an atmosphere. They concluded that contributions from individual meteorites were small and were unlikely to have a significant impact on the atmospheres of planets on their own. The researchers then analysed data from an ancient meteorite shower called the Late Heavy Bombardment (LHB), which occurred 4 billion years ago, where millions of rocks crashed to Earth and Mars over a period of 20 million years. Using published models of meteoritic impact rates during the LHB, the researchers calculated that 10 billion tonnes of carbon dioxide and 10 billion tonnes of water vapour could have been delivered to the atmospheres of Earth and Mars each year. This suggests that the LHB could have delivered enough carbon dioxide and water vapour to turn the atmospheres of the two planets into warmer and wetter environments that were more habitable for life, say the researchers. Professor Mark Sephton, from Imperial's Department of Earth Science and Engineering believes the study provides important clues about Earth's ancient past: "For a long time, scientists have been trying to understand why Earth is so water rich compared to other planets in our solar system. The LHB may provide a clue. This may have been a pivotal moment in our early history where Earth's gaseous envelope finally had enough of the right ingredients to nurture life on our planet." Lead- author of the study, Dr Richard Court from Imperial's Department of Earth Science and Engineering, adds: "Because of their chemistry, ancient meteorites have been suggested as a way of furnishing the early Earth with its liquid water. Now we have data that reveals just how much water and carbon dioxide was directly injected into the atmosphere by meteorites. These gases could have got to work immediately, boosting the water cycle and warming the planet." However, researchers say Mars' good fortune did not last. Unlike Earth, Mars doesn't have a magnetic field to act as a protective shield from the Sun's solar wind. As a consequence, Mars was stripped of most of its atmosphere. A reduction in volcanic activity also cooled the planet. This caused its liquid oceans to retreat to the poles where they became ice. More information: "Meteorite ablation products and their contribution to the atmospheres of terrestrial planets: An experimental study using pyrolysis-FTIR", Geochemica et Cosmochima Acta, Monday 1 June 2009 (Print publication) Source: Imperial College London (news : web) Explore further: More than 2,200 confirmed dead in Nepal earthquake
The Domain Name System (DNS) is a part of the Internet protocol suite (TCP/IP) and is a naming system for the Internet resources. DNS was designed in the early 1980s, and was launched in 1985; it has since become a core service of the Internet. The Internet has two namespaces: domain names and IP addresses: IP addresses (numerical) are assigned to every device that connects to the Internet, and domain name addresses (alphanumeric) are used to easily locate IP addresses. IP addresses (Internet Protocol) were designed before DNS, but it was always acknowledged that using numerical addresses to find resources was not user-friendly. The solution was the Domain Name System (DNS): which consists of alphanumeric domain names -- such as internet-guide.co.uk -- that are easy to memorise and can be mapped to an IP address; resulting in users only needing to know a domain name to find a resource on the Internet. The roots of the Domain Name System can be traced back to the ARPANET computer network (forerunner to the Internet) when computer scientists attempted to improve the simplicity of finding resources on it. ARPANET was based upon a numerical address system (Assigned Numbers List), which was maintained by Stanford Research Institute and Jon Postel at the Information Sciences Institute (ISI). Due to the difficulty of memorising numerical addresses, host names with alphabetical character strings were introduced to ARPANET. While alphabetic hostnames were useful for identifying host computers, the underlying network still used numeric addresses. The Stanford Research Institute created the Network Information Center (NIC) in 1972 -- Elizabeth "Jake" Feinler headed the project -- to manage the list of host names. Jon Postel assigned the numbers, and the Network Information Center (NIC) distributed them and handled inquiries from users. The NIC distributed a master list of hostnames, mapped to numerical addresses, in a text file named: HOSTS.TXT. The problem with this system was that each ARPANET node (location) had to manually download and update their HOSTS.TXT file. This became a problem as more and more nodes were added to ARPANET, and the inherent unreliability of relying on nodes to manually update a single HOSTS.TXT file became apparent. By the early 1980s, the early ARPANET protocols had been replaced with TCP/IP, but, the problem still remained for finding a refined solution for mapping numerical addresses to host names. A meeting was held on the 11th of January 1982 -- at the USC Information Sciences Institute -- to solve the problem and an "interesting idea" was suggested at this meeting: the idea was 'Name Domains' (RFC 805). In 1983, Paul Mockapetris was asked by Jon Postel to evaluate a range of proposals for 'Name Domains' which Mockapetris developed into the Domain Name System (DNS). The Domain Name System was implemented in 1984, and it would become a centralised system for distributing and resolving naming issues on TCP/IP networks (ARPANET and the Internet etc). The specification of the Domain Name System (DNS) was outlined in the following RFC documents: RFC 881, RFC 882, RFC 883, RFC 1034 and RFC 1035. In 1990, according to RFC 1174, the management of Internet numbers was still 'in the hands' of a central authority; named in this RFC as the Internet Assigned Numbers Authority (Jon Postel) and an Internet Registry (IR) named the Network Information Center (DDN-NIC). The DNS root zone was administrated exclusively by IANA from 1984-1998; Jon Postel was the head of IANA during this period. From 1984-1990, the Defense Data Network Information Center (DDN-NIC) administrated the Top Level Domains of the DNS (com, net, org, edu etc) and provided a root name server. However, in 1990, the Internet Activities Board (IAB) proposed a change to the centralised control of the Domain Name System (DNS): while IANA would continue to manage the root zone of the DNS, management of the Top Level Domains would transfer from the Network Information Center (NIC) to Network Solutions, Inc. (NSI), and from its management location of SRI International to Government Systems (GSI). Network Solutions, Inc. (NSI) would initiate a fee structure for registering domain names; previously they were given out for free. By 1998, there was a concern that a monopoly had formed in relation to the management of Top Level Domains. Another issue would also arise, initiated by Jon Postel. In 1998, Jon Postel caused controversy when he instructed eight regional root name servers to change the root zone server they "pulled" information from (to IANA); essentially hijacking control of the Internet. In response, the (NTIA) National Telecommunications and Information Administration of the (DOC) United States Department of Commerce created a document named: "A proposal to improve technical management of Internet names and addresses". The U.S. government was obviously alarmed by the power Jon Postel (who created IANA, alongside Joyce Reynolds) yielded upon the Internet. The result of the NTIA document was the creation of ICANN in 1998; IANA became a department within it. ICANN was created as a non-profit organisation, but it was under contract from the United States Department of Commerce (DOC). The NTIA provided oversight. ICANN has managed the Domain Name System (DNS) from 1998 to the present day, and assigns organisations to manage zones in the DNS and accredits registrars to manage domain names on behalf of registrants; such as IANA who manage the DNS root zone. There was demand -- supported by many of the pioneers of the Internet -- to transition management of the namespace of the Internet from the U.S. government to a global multi-stakeholder community. In 2013, the 'Montevideo Statement on the Future of Internet Cooperation' was released, signed by leaders of many important Internet organisations: it warned against NSA surveillance of the Internet, and urged for greater international oversight of the Internet. On the 1st of October 2016, ICANN was freed from its United States Department of Commerce (DOC) oversight contract. ICANN now had the "keys to the kingdom", with ultimate authority over the Domain Name System (DNS) and Internet numbers; the namespace of the Internet has passed to an international multi-stakeholder arrangement. Due to the importance of the Domain Name System (DNS), management and maintenance is required. While the Internet has no central government, the assignment of "space" (IP, DNS, ASN) on the Internet is strictly managed. The Domain Name System is managed by the following organisations: (Pictured: ICANN's management of the DNS, and Verisign's of the .com registry has remained controversial) The Domain Name System is a hierarchical system, and at the top of the hierarchy is the DNS root zone. IANA manages the DNS root zone -- with oversight provided by ICANN -- by administrating the data (root zone file) in the root name servers. Alongside maintaining the Root Zone File, ICANN also maintains the Root Zone Database (information published in the WHOIS service) and manages the Key Signing Key (KSK): which provides DNS security using DNSSEC. ICANN creates policy for root zone management through advice provided by two technical bodies: Root Server System Advisory Committee (RSSAC) and the Security and Stability Advisory Committee (SSAC). ICANN assigns organisations to manage Top Level Domains (such as the com domain) and accredits registrars who buy and manage namespace -- on behalf of companies and individuals -- within these Top Level Domains. There are currently in the region of 1000 accredited registrars (such as GoDaddy); some of who assign third party registrars. Global policy for Top Level Domains is developed by two ICANN organisations: Generic Names Supporting Organization (GNSO) and Country Code Names Supporting Organization (ccNSO). ICANN also delegates responsibility for IP number assignment, and some DNS functions, to five Regional Internet Registries (RIPE NCC, LACNIC, APNIC, ARIN, AfriNIC) who comprise the Number Resource Organization. While ICANN is the ultimate authority for managing the Domain Name System (DNS), it does so be delegating administrative responsibility to a range of organisations who set policy by taking advice from a range of committees; some of which are comprised of representatives from national governments and super-national bodies. The Domain Name System is structured in hierarchical zones: The DNS root zone is the highest zone within the Domain Name System, and is name-less. When examining the domain name google.com, it is fairly obvious it consists of two labels; which are separated by dots (.). Labels are limited to sixty-three characters and the characters allowed in the label are from a ASCII character set. The importance of the label - in terms of its hierarchy - moves from right to left. Each label, which is to the left, can be described as a subdomain of the label to it's right. The amount of subdomains is restricted to one hundred and twenty-seven. For the domain google.com the com label is the Top Level Domain and google label is the Second Level Domain. In theory, there is virtually no end (127) to the amount of domain name subdomains, but most domain names do not exceed the following: example.co.ss.co.com. The full domain name is limited to two hundred and fifty-three characters. There are two kinds of name servers: authoritative name servers and cache name servers. The purpose of authoritative name servers is to store DNS records for domain zones and to respond to queries. DNS resource records have different record types, such as 'AAAA', which is a 128-bit IPv6 address. Authoritative name servers are structured in a hierarchy, with the highest level being the root name servers; listed below. The root name servers store data -- in a root zone file -- about the Top level domains; this data is provided to the root name servers by the Internet Assigned Numbers Authority (IANA). Therefore, the root name servers are an authoritative source for any query related to a Top Level Domain. The operators of Top Level Domains -- assigned by ICANN -- run authoritative name servers for their zone and also creates and publish a zone file for all the active domain names in their zone. Therefore, the DNS zone descends like a tree structure with individual organisations and authoritative name servers responsible for each zone. The DNS root zone is currently served by thirteen authoritative root name servers, which are: a.root-servers.net VeriSign, Inc.; b.root-servers.net University of Southern California (ISI); c.root-servers.net Cogent Communications; d.root-servers.net University of Maryland; e.root-servers.net NASA (Ames Research Center); f.root-servers.net Internet Systems Consortium, Inc.; g.root-servers.net US Department of Defense (NIC); h.root-servers.net US Army (Research Lab); i.root-servers.net Netnod; j.root-servers.net VeriSign, Inc.; k.root-servers.net RIPE NCC; l.root-servers.net ICANN; and m.root-servers.net WIDE Project. There is no single server for each root name server, the burden is spread across multiple locations; for example, the LINX (London Internet Exchange) provides services for the k.root-servers.net RIPE NCC root nameserver. The other type of name server is a cache name server: these are operated by DNS resolvers - DNS resolvers are typically operated by Internet Service Providers. Cache name servers store DNS lookup queries from its users to improve performance and lessen the burden on the authoritative name servers. The Domain Name System (DNS) is run on a client-server model, with end-users using a client to query authoritative name servers that store data records for domain names. The client side of the DNS process is referred to as a DNS resolver or a DNS lookup. The purpose of the resolver is to initiate and finish a DNS query, and does so by translating a domain name (inserted into the client) into an IP address (stored on a name server). DNS resolvers can resolve a query by using one of three query processes: non-recursive, recursive, or iterative queries. Non-recursive queries will only query a single name server, recursive queries will be passed to more than one name server if they receive an inadequate response from the first name server, and iterative queries will query name servers in a chain process. DNS resolvers typically cache their queries locally in a cache name server. A reverse DNS lookup can also be performed: this is when a IP address is known but not the domain name(s) operating on it. DNS queries use the User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) to serve their request. The DNS resolver is not directly interacted with by users; their web client (browser) will handle the process in combination with their local operating system. Most modern operating systems include networking software; such as Windows 10. Typically, the networking software of an operating system can be manually configured. Generally speaking, the network settings will be set to use the DNS server of the users Internet Service Provider, but it can be manually changed to a third party DNS server. What are the reasons for doing so? To improve performance, improve security, bypass censorship, protect against phishing, and to implement parental controls. Not all Internet Service Providers provide good DNS resolvers and caching services. The question may arise, why aren't all domain queries routed through the root nameservers: for performance, the root nameservers could not handle billions of requests, and, therefore, the burden is spread amongst a hierarchy of name servers that store DNS records and respond to queries. Therefore, the Domain Name System is often described as a distributed database. Name servers typically use the BIND (Berkeley Internet Name Domain) DNS software to handle DNS queries. Top Level Domains (TLDs) are managed by an organisation assigned by ICANN; these organisations do not own the Top Level Domain, they are under contract from ICANN to manage the domain for a specified amount of time. The com Top Level Domain has been managed by more than one organisation in its history (Network Solutions (NSI) and Versign). Organisations who operate a Top Level Domain are responsible for the following: publishing a zone file; operating a authoritative nameserver; and maintaining a registry database. There are other requirements outlined in ICANN's registry agreement. Companies, organisations, and individuals can register a namespace within a Top Level Domain, which is called a Second Level Domain (such as the namespace google within the com domain). However, some Top Level Domain managers (like Nominet for the uk ccTLD) have previously imposed Third Level Domains, for example: co.uk, ac.uk. This meant that a registrant could not register a Second Level Domain within the uk Country Code Top Level Domain (recently changed with the introduction of the uk Top Level Domain). The registration of a Second Level Domain -- by the general public -- is conducted via registrars who are accredited by ICANN. Registrars register Second Level Domains on behalf of registrants. Registrars have to pay a fee to the organisation who manages a Top Level Domain. ICANN also receive a small fee from every TLD registration. The registrar system was officially launched by ICANN on the 30th of November, 1999. One of the first registrar's accredited by ICANN was Godaddy. There are currently (2014) over nine hundred accredited registrars. A list of accredited registrars was published at the InterNIC website (www.internic.net/alpha.html); although this list may be out of date. The InterNIC website heavily redirects to the ICANN website; and may be defunct (as of 2014). Registrars pay a fee to ICANN to become a registrar; an individual/company can apply to become a registrar by visiting the ICANN website and applying through their instructions. Some accredited UK registrars include: 123-Reg Limited, Astutium Limited, BB-Online UK Limited, Demys Limited, Discount Domains Ltd., Domainbox Limited, Domainmonster Limited, Domains.coop Limited, Easyspace Limited, LCN.COM Ltd., Lexsynergy Limited, LiquidNet Ltd., NameCamp Limited, NetEarth One Inc. d/b/a NetEarth, Netistrar Limited, Nominet Registrar Services Limited, Paragon Internet Group Ltd t/a Paragon Names, TLD Registrar Solutions Ltd, and UK-2 Limited. The process of registering a Second Level Domain is as follows: There are currently over 1000 Top Level Domains and over 900 accredited ICANN registrars who can facilitate the registration process. Abuse and Disputes Abuse of domain names and the Domain Name System does occurred. Cyber squatting is usually viewed as one such abuse: where end-users buy a domain name just so that another interested "party" cannot, and then, either extorts a fee to sell it, or hold onto it out of spite (the ethical version of cyber squatting is DNS parking: registering a domain name with the intention of using it in the future). Domain name disputes occur for a multitude of reasons: when a registrar goes out of business, cannot be contacted, or purposely/mistakenly registers a domain names in their own name instead of the registrant's. ICANN publish guidelines for registrars and accredit registrars, therefore, ICANN is the ultimate authority for resolving disputes for gTLD's. For ccTLD's (like the uk domain administered by Nominet) guidelines and disputes are resolved by the country code manager. Transfer a Domain Name As previously discussed, end-users has to register domain names through accredited registrars. The registrar is a 'middle man' who contacts the manager (registry) of a domain to purchase a namespace -- at that domain -- on behalf of the end-user. Registrars also manage the domain name on behalf of the end-user; renewing the domain and alteration to the DNS record. Some registrars allow full DNS control of a domain name, while others do not. ICANN allow end-users (registrants) to switch registrars; which is outlined in their 'The Inter-Registrar Transfer Policy'. The current manager (registrar) of a domain name can charge a fee for transferring a domain name to another registrar, but, the process for transferring domain names does vary slightly for each type of domain. The 'Initial Authorization for Registrar Transfer form' is used for transferring a range of gTLD's (not mil and gov domains), but, the IPS TAG is used by Nominet to switch uk ccTLD's.
7th grade math 10 points 1.) jill began to solve an equation. which expression below shows the next step jill needs to take? y divided by (-2)=4.5 y divided by (-2)(-2) 4.5 • (–2) 4.5 ÷ (–2) 4.5 + (–2) 4.5 – (–2) a. we have two lines: y = 4-x and y = 8-x^-1 given two simultaneous equations that are both to be true, then the solution is the points where the lines cross. the intersection is where the two equations are equal. therefore the solution that works for both equations is when 4-x = 8-x^-1 this is where the two lines will cross and that is the common point that satisfies both equations. b. 4-x = 8-x^-1 x 4-x 8-x^-1 -2 6 8.5 -1 5 9 3 1 7.67 the table shows that none of the x values from -3 to 3 is the solution because in no case does 4-x = 8-x^-1 to find the solution we need to rearrange the equation to find for x: 4-x = 8-x^-1 multiply both sides with x: 4x-x^2 = 8x-1 x= -4.236, 0.236 therefore there are two points that satisfies the y = 4-x = 4 – (-4.236) y = 8-x^-1 = .236)^-1 y = 4-x = 4 – (0.236) = 3.764 y = 8-x^-1 = 8-(0.236)^-1 thus the two lines cross at 2 points: (-4.236, 8.236) & (0.236, 3.764) c. to solve graphically the equation 4-x = 8-x^-1 we would graph both lines: y = 4-x and y the point on the graph where the lines cross is the solution to the system of equations. just graph the points on part b on a cartesian coordinate system and extend the two lines. the solution is, as stated, the point where the two lines cross on the graph. x + 4/7 - What type of graph would you use to compare the prices of Felix's books and of Tyler's books? In two or more sentences, explain your choice. bar graph line graph scatter plot hist... - Which quadratic function is represented by the graph?... - Que es una proporcionalidad sos... - 1. 4 pound of nails are to be packed in 12 bags. how many pound are in each bag? 2. A 2:15 scaled pattern for a mural is 10 feet long. how long will the mural be?... - Calculate 5/10÷9 please... - How to interprete inequality... - NEED HELP ASAP!! will mark brainlist* Question: State the order and type of each transformation of the graph of the function f(x)=4(x+9)^2 as compared to the graph of the base fu... - 1 1/4 x 3 5/6 need helppp...2 answer(s) · Mathematics - Which of the following is a proper way to enter an answer of 1.666 on the SAT SPR answer grid? 1.666...2 answer(s) · Mathematics - What is the area of the rectangle? answers: 120 m 120 m2 120m3 120 cubic meters top of the rectangle: 12 m bottom of the rectangle:12 m side of the rectangle: 10 m side of th...
Confirmation bias, also called confirmatory bias or myside bias,[Note 1] is the tendency to search for, interpret, favor, and recall information in a way that confirms one's preexisting beliefs or hypotheses. It is a type of cognitive bias and a systematic error of inductive reasoning. People display this bias when they gather or remember information selectively, or when they interpret it in a biased way. The effect is stronger for emotionally charged issues and for deeply entrenched beliefs. Confirmation bias is a variation of the more general tendency of apophenia. People also tend to interpret ambiguous evidence as supporting their existing position. Biased search, interpretation and memory have been invoked to explain attitude polarization (when a disagreement becomes more extreme even though the different parties are exposed to the same evidence), belief perseverance (when beliefs persist after the evidence for them is shown to be false), the irrational primacy effect (a greater reliance on information encountered early in a series) and illusory correlation (when people falsely perceive an association between two events or situations). A series of psychological experiments in the 1960s suggested that people are biased toward confirming their existing beliefs. Later work re-interpreted these results as a tendency to test ideas in a one-sided way, focusing on one possibility and ignoring alternatives. In certain situations, this tendency can bias people's conclusions. Explanations for the observed biases include wishful thinking and the limited human capacity to process information. Another explanation is that people show confirmation bias because they are weighing up the costs of being wrong, rather than investigating in a neutral, scientific way. However, even scientists can be prone to confirmation bias. Confirmation biases contribute to overconfidence in personal beliefs and can maintain or strengthen beliefs in the face of contrary evidence. Poor decisions due to these biases have been found in political and organizational contexts. - 1 Types - 2 Related effects - 3 Individual differences - 4 History - 5 Explanations - 6 Consequences - 7 See also - 8 Notes - 9 References - 10 Sources - 11 Further reading - 12 External links Confirmation biases are effects in information processing. They differ from what is sometimes called the behavioral confirmation effect, commonly known as self-fulfilling prophecy, in which a person's expectations influence their own behavior, bringing about the expected result. Some psychologists restrict the term confirmation bias to selective collection of evidence that supports what one already believes while ignoring or rejecting evidence that supports a different conclusion. Others apply the term more broadly to the tendency to preserve one's existing beliefs when searching for evidence, interpreting it, or recalling it from memory.[Note 2] Biased search for information Experiments have found repeatedly that people tend to test hypotheses in a one-sided way, by searching for evidence consistent with their current hypothesis. Rather than searching through all the relevant evidence, they phrase questions to receive an affirmative answer that supports their theory. They look for the consequences that they would expect if their hypothesis were true, rather than what would happen if they were false. For example, someone using yes/no questions to find a number he or she suspects to be the number 3 might ask, "Is it an odd number?" People prefer this type of question, called a "positive test", even when a negative test such as "Is it an even number?" would yield exactly the same information. However, this does not mean that people seek tests that guarantee a positive answer. In studies where subjects could select either such pseudo-tests or genuinely diagnostic ones, they favored the genuinely diagnostic. The preference for positive tests in itself is not a bias, since positive tests can be highly informative. However, in combination with other effects, this strategy can confirm existing beliefs or assumptions, independently of whether they are true. In real-world situations, evidence is often complex and mixed. For example, various contradictory ideas about someone could each be supported by concentrating on one aspect of his or her behavior. Thus any search for evidence in favor of a hypothesis is likely to succeed. One illustration of this is the way the phrasing of a question can significantly change the answer. For example, people who are asked, "Are you happy with your social life?" report greater satisfaction than those asked, "Are you unhappy with your social life?" Even a small change in a question's wording can affect how people search through available information, and hence the conclusions they reach. This was shown using a fictional child custody case. Participants read that Parent A was moderately suitable to be the guardian in multiple ways. Parent B had a mix of salient positive and negative qualities: a close relationship with the child but a job that would take him or her away for long periods of time. When asked, "Which parent should have custody of the child?" the majority of participants chose Parent B, looking mainly for positive attributes. However, when asked, "Which parent should be denied custody of the child?" they looked for negative attributes and the majority answered that Parent B should be denied custody, implying that Parent A should have custody. Similar studies have demonstrated how people engage in a biased search for information, but also that this phenomenon may be limited by a preference for genuine diagnostic tests. In an initial experiment, participants rated another person on the introversion–extroversion personality dimension on the basis of an interview. They chose the interview questions from a given list. When the interviewee was introduced as an introvert, the participants chose questions that presumed introversion, such as, "What do you find unpleasant about noisy parties?" When the interviewee was described as extroverted, almost all the questions presumed extroversion, such as, "What would you do to liven up a dull party?" These loaded questions gave the interviewees little or no opportunity to falsify the hypothesis about them. A later version of the experiment gave the participants less presumptive questions to choose from, such as, "Do you shy away from social interactions?" Participants preferred to ask these more diagnostic questions, showing only a weak bias towards positive tests. This pattern, of a main preference for diagnostic tests and a weaker preference for positive tests, has been replicated in other studies. Personality traits influence and interact with biased search processes. Individuals vary in their abilities to defend their attitudes from external attacks in relation to selective exposure. Selective exposure occurs when individuals search for information that is consistent, rather than inconsistent, with their personal beliefs. An experiment examined the extent to which individuals could refute arguments that contradicted their personal beliefs. People with high confidence levels more readily seek out contradictory information to their personal position to form an argument. Individuals with low confidence levels do not seek out contradictory information and prefer information that supports their personal position. People generate and evaluate evidence in arguments that are biased towards their own beliefs and opinions. Heightened confidence levels decrease preference for information that supports individuals' personal beliefs. Another experiment gave participants a complex rule-discovery task that involved moving objects simulated by a computer. Objects on the computer screen followed specific laws, which the participants had to figure out. So, participants could "fire" objects across the screen to test their hypotheses. Despite making many attempts over a ten-hour session, none of the participants figured out the rules of the system. They typically attempted to confirm rather than falsify their hypotheses, and were reluctant to consider alternatives. Even after seeing objective evidence that refuted their working hypotheses, they frequently continued doing the same tests. Some of the participants were taught proper hypothesis-testing, but these instructions had almost no effect. Confirmation biases are not limited to the collection of evidence. Even if two individuals have the same information, the way they interpret it can be biased. A team at Stanford University conducted an experiment involving participants who felt strongly about capital punishment, with half in favor and half against it. Each participant read descriptions of two studies: a comparison of U.S. states with and without the death penalty, and a comparison of murder rates in a state before and after the introduction of the death penalty. After reading a quick description of each study, the participants were asked whether their opinions had changed. Then, they read a more detailed account of each study's procedure and had to rate whether the research was well-conducted and convincing. In fact, the studies were fictional. Half the participants were told that one kind of study supported the deterrent effect and the other undermined it, while for other participants the conclusions were swapped. The participants, whether supporters or opponents, reported shifting their attitudes slightly in the direction of the first study they read. Once they read the more detailed descriptions of the two studies, they almost all returned to their original belief regardless of the evidence provided, pointing to details that supported their viewpoint and disregarding anything contrary. Participants described studies supporting their pre-existing view as superior to those that contradicted it, in detailed and specific ways. Writing about a study that seemed to undermine the deterrence effect, a death penalty proponent wrote, "The research didn't cover a long enough period of time," while an opponent's comment on the same study said, "No strong evidence to contradict the researchers has been presented." The results illustrated that people set higher standards of evidence for hypotheses that go against their current expectations. This effect, known as "disconfirmation bias", has been supported by other experiments. Another study of biased interpretation occurred during the 2004 U.S. presidential election and involved participants who reported having strong feelings about the candidates. They were shown apparently contradictory pairs of statements, either from Republican candidate George W. Bush, Democratic candidate John Kerry or a politically neutral public figure. They were also given further statements that made the apparent contradiction seem reasonable. From these three pieces of information, they had to decide whether or not each individual's statements were inconsistent.:1948 There were strong differences in these evaluations, with participants much more likely to interpret statements from the candidate they opposed as contradictory.:1951 In this experiment, the participants made their judgments while in a magnetic resonance imaging (MRI) scanner which monitored their brain activity. As participants evaluated contradictory statements by their favored candidate, emotional centers of their brains were aroused. This did not happen with the statements by the other figures. The experimenters inferred that the different responses to the statements were not due to passive reasoning errors. Instead, the participants were actively reducing the cognitive dissonance induced by reading about their favored candidate's irrational or hypocritical behavior.:1956 Biases in belief interpretation are persistent, regardless of intelligence level. Participants in an experiment took the SAT test (a college admissions test used in the United States) to assess their intelligence levels. They then read information regarding safety concerns for vehicles, and the experimenters manipulated the national origin of the car. American participants provided their opinion if the car should be banned on a six-point scale, where one indicated "definitely yes" and six indicated "definitely no". Participants firstly evaluated if they would allow a dangerous German car on American streets and a dangerous American car on German streets. Participants believed that the dangerous German car on American streets should be banned more quickly than the dangerous American car on German streets. There was no difference among intelligence levels at the rate participants would ban a car. Biased interpretation is not restricted to emotionally significant topics. In another experiment, participants were told a story about a theft. They had to rate the evidential importance of statements arguing either for or against a particular character being responsible. When they hypothesized that character's guilt, they rated statements supporting that hypothesis as more important than conflicting statements. People may remember evidence selectively to reinforce their expectations, even if they gather and interpret evidence in a neutral manner. This effect is called "selective recall", "confirmatory memory", or "access-biased memory". Psychological theories differ in their predictions about selective recall. Schema theory predicts that information matching prior expectations will be more easily stored and recalled than information that does not match. Some alternative approaches say that surprising information stands out and so is memorable. Predictions from both these theories have been confirmed in different experimental contexts, with no theory winning outright. In one study, participants read a profile of a woman which described a mix of introverted and extroverted behaviors. They later had to recall examples of her introversion and extroversion. One group was told this was to assess the woman for a job as a librarian, while a second group were told it was for a job in real estate sales. There was a significant difference between what these two groups recalled, with the "librarian" group recalling more examples of introversion and the "sales" groups recalling more extroverted behavior. A selective memory effect has also been shown in experiments that manipulate the desirability of personality types. In one of these, a group of participants were shown evidence that extroverted people are more successful than introverts. Another group were told the opposite. In a subsequent, apparently unrelated study, participants were asked to recall events from their lives in which they had been either introverted or extroverted. Each group of participants provided more memories connecting themselves with the more desirable personality type, and recalled those memories more quickly. Changes in emotional states can also influence memory recall. Participants rated how they felt when they had first learned that O.J. Simpson had been acquitted of murder charges. They described their emotional reactions and confidence regarding the verdict one week, two months, and one year after the trial. Results indicated that participants' assessments for Simpson's guilt changed over time. The more that participants' opinion of the verdict had changed, the less stable were the participant's memories regarding their initial emotional reactions. When participants recalled their initial emotional reactions two months and a year later, past appraisals closely resembled current appraisals of emotion. People demonstrate sizable myside bias when discussing their opinions on controversial topics. Memory recall and construction of experiences undergo revision in relation to corresponding emotional states. Myside bias has been shown to influence the accuracy of memory recall. In an experiment, widows and widowers rated the intensity of their experienced grief six months and five years after the deaths of their spouses. Participants noted a higher experience of grief at six months rather than at five years. Yet, when the participants were asked after five years how they had felt six months after the death of their significant other, the intensity of grief participants recalled was highly correlated with their current level of grief. Individuals appear to utilize their current emotional states to analyze how they must have felt when experiencing past events. Emotional memories are reconstructed by current emotional states. One study showed how selective memory can maintain belief in extrasensory perception (ESP). Believers and disbelievers were each shown descriptions of ESP experiments. Half of each group were told that the experimental results supported the existence of ESP, while the others were told they did not. In a subsequent test, participants recalled the material accurately, apart from believers who had read the non-supportive evidence. This group remembered significantly less information and some of them incorrectly remembered the results as supporting ESP. Polarization of opinion When people with opposing views interpret new information in a biased way, their views can move even further apart. This is called "attitude polarization". The effect was demonstrated by an experiment that involved drawing a series of red and black balls from one of two concealed "bingo baskets". Participants knew that one basket contained 60% black and 40% red balls; the other, 40% black and 60% red. The experimenters looked at what happened when balls of alternating color were drawn in turn, a sequence that does not favor either basket. After each ball was drawn, participants in one group were asked to state out loud their judgments of the probability that the balls were being drawn from one or the other basket. These participants tended to grow more confident with each successive draw—whether they initially thought the basket with 60% black balls or the one with 60% red balls was the more likely source, their estimate of the probability increased. Another group of participants were asked to state probability estimates only at the end of a sequence of drawn balls, rather than after each ball. They did not show the polarization effect, suggesting that it does not necessarily occur when people simply hold opposing positions, but rather when they openly commit to them. A less abstract study was the Stanford biased interpretation experiment in which participants with strong opinions about the death penalty read about mixed experimental evidence. Twenty-three percent of the participants reported that their views had become more extreme, and this self-reported shift correlated strongly with their initial attitudes. In later experiments, participants also reported their opinions becoming more extreme in response to ambiguous information. However, comparisons of their attitudes before and after the new evidence showed no significant change, suggesting that the self-reported changes might not be real. Based on these experiments, Deanna Kuhn and Joseph Lao concluded that polarization is a real phenomenon but far from inevitable, only happening in a small minority of cases. They found that it was prompted not only by considering mixed evidence, but by merely thinking about the topic. Charles Taber and Milton Lodge argued that the Stanford team's result had been hard to replicate because the arguments used in later experiments were too abstract or confusing to evoke an emotional response. The Taber and Lodge study used the emotionally charged topics of gun control and affirmative action. They measured the attitudes of their participants towards these issues before and after reading arguments on each side of the debate. Two groups of participants showed attitude polarization: those with strong prior opinions and those who were politically knowledgeable. In part of this study, participants chose which information sources to read, from a list prepared by the experimenters. For example, they could read the National Rifle Association's and the Brady Anti-Handgun Coalition's arguments on gun control. Even when instructed to be even-handed, participants were more likely to read arguments that supported their existing attitudes than arguments that did not. This biased search for information correlated well with the polarization effect. The backfire effect is a name for the finding that, given evidence against their beliefs, people can reject the evidence and believe even more strongly. The phrase was first coined by Brendan Nyhan and Jason Reifler. Persistence of discredited beliefs Confirmation biases can be used to explain why some beliefs persist when the initial evidence for them is removed. This belief perseverance effect has been shown by a series of experiments using what is called the "debriefing paradigm": participants read fake evidence for a hypothesis, their attitude change is measured, then the fakery is exposed in detail. Their attitudes are then measured once more to see if their belief returns to its previous level. A common finding is that at least some of the initial belief remains even after a full debriefing. In one experiment, participants had to distinguish between real and fake suicide notes. The feedback was random: some were told they had done well while others were told they had performed badly. Even after being fully debriefed, participants were still influenced by the feedback. They still thought they were better or worse than average at that kind of task, depending on what they had initially been told. In another study, participants read job performance ratings of two firefighters, along with their responses to a risk aversion test. This fictional data was arranged to show either a negative or positive association: some participants were told that a risk-taking firefighter did better, while others were told they did less well than a risk-averse colleague. Even if these two case studies were true, they would have been scientifically poor evidence for a conclusion about firefighters in general. However, the participants found them subjectively persuasive. When the case studies were shown to be fictional, participants' belief in a link diminished, but around half of the original effect remained. Follow-up interviews established that the participants had understood the debriefing and taken it seriously. Participants seemed to trust the debriefing, but regarded the discredited information as irrelevant to their personal belief. The continued influence effect is the tendency to believe previously learned misinformation even after it has been corrected. Misinformation can still influence inferences one generates after a correction has occurred. Preference for early information Experiments have shown that information is weighted more strongly when it appears early in a series, even when the order is unimportant. For example, people form a more positive impression of someone described as "intelligent, industrious, impulsive, critical, stubborn, envious" than when they are given the same words in reverse order. This irrational primacy effect is independent of the primacy effect in memory in which the earlier items in a series leave a stronger memory trace. Biased interpretation offers an explanation for this effect: seeing the initial evidence, people form a working hypothesis that affects how they interpret the rest of the information. One demonstration of irrational primacy used colored chips supposedly drawn from two urns. Participants were told the color distributions of the urns, and had to estimate the probability of a chip being drawn from one of them. In fact, the colors appeared in a prearranged order. The first thirty draws favored one urn and the next thirty favored the other. The series as a whole was neutral, so rationally, the two urns were equally likely. However, after sixty draws, participants favored the urn suggested by the initial thirty. Another experiment involved a slide show of a single object, seen as just a blur at first and in slightly better focus with each succeeding slide. After each slide, participants had to state their best guess of what the object was. Participants whose early guesses were wrong persisted with those guesses, even when the picture was sufficiently in focus that the object was readily recognizable to other people. Illusory association between events Illusory correlation is the tendency to see non-existent correlations in a set of data. This tendency was first demonstrated in a series of experiments in the late 1960s. In one experiment, participants read a set of psychiatric case studies, including responses to the Rorschach inkblot test. The participants reported that the homosexual men in the set were more likely to report seeing buttocks, anuses or sexually ambiguous figures in the inkblots. In fact the fictional case studies had been constructed so that the homosexual men were no more likely to report this imagery or, in one version of the experiment, were less likely to report it than heterosexual men. In a survey, a group of experienced psychoanalysts reported the same set of illusory associations with homosexuality. Another study recorded the symptoms experienced by arthritic patients, along with weather conditions over a 15-month period. Nearly all the patients reported that their pains were correlated with weather conditions, although the real correlation was zero. This effect is a kind of biased interpretation, in that objectively neutral or unfavorable evidence is interpreted to support existing beliefs. It is also related to biases in hypothesis-testing behavior. In judging whether two events, such as illness and bad weather, are correlated, people rely heavily on the number of positive-positive cases: in this example, instances of both pain and bad weather. They pay relatively little attention to the other kinds of observation (of no pain and/or good weather). This parallels the reliance on positive tests in hypothesis testing. It may also reflect selective recall, in that people may have a sense that two events are correlated because it is easier to recall times when they happened together. Myside bias was once believed to be associated with greater intelligence; however, studies have shown that myside bias can be more influenced by ability to rationally think as opposed to level of intelligence. Myside bias can cause an inability to effectively and logically evaluate the opposite side of an argument. Studies have stated that myside bias is an absence of "active open-mindedness", meaning the active search for why an initial idea may be wrong. Typically, myside bias is operationalized in empirical studies as the quantity of evidence used in support of their side in comparison to the opposite side. A study has found individual differences in myside bias. This study investigates individual differences that are acquired through learning in a cultural context and are mutable. The researcher found important individual difference in argumentation. Studies have suggested that individual differences such as deductive reasoning ability, ability to overcome belief bias, epistemological understanding, and thinking disposition are significant predictors of the reasoning and generating arguments, counterarguments, and rebuttals. A study by Christopher Wolfe and Anne Britt also investigated how participants' views of "what makes a good argument?" can be a source of myside bias that influence the way a person formulates his own arguments. The study investigated individual differences of argumentation schema and asked participants to write essays. The participants were randomly assigned to write essays either for or against their preferred side of an argument and were given research instructions that took either a balanced or an unrestricted approach. The balanced-research instructions directed participants to create a "balanced" argument, i.e., that included both pros and cons; the unrestricted-research instructions included nothing on how to create the argument. Overall, the results revealed that the balanced-research instructions significantly increased the incidence of opposing information in arguments. These data also reveal that personal belief is not a source of myside bias; however, that those participants, who believe that a good argument is one that is based on facts, are more likely to exhibit myside bias than other participants. This evidence is consistent with the claims proposed in Baron's article—that people's opinions about what makes good thinking can influence how arguments are generated. Before psychological research on confirmation bias, the phenomenon had been observed throughout history. Beginning with the Greek historian Thucydides (c. 460 BC – c. 395 BC), who wrote of misguided treason in The Peloponnesian War; "... for it is a habit of mankind to entrust to careless hope what they long for, and to use sovereign reason to thrust aside what they do not fancy". Italian poet Dante Alighieri (1265–1321), noted it in his famous work, the Divine Comedy, in which St. Thomas Aquinas cautions Dante upon meeting in Paradise, "opinion—hasty—often can incline to the wrong side, and then affection for one's own opinion binds, confines the mind". Ibn Khaldun noticed the same effect in his Muqaddimah: "Untruth naturally afflicts historical information. There are various reasons that make this unavoidable. One of them is partisanship for opinions and schools. [...] if the soul is infected with partisanship for a particular opinion or sect, it accepts without a moment's hesitation the information that is agreeable to it. Prejudice and partisanship obscure the critical faculty and preclude critical investigation. The result is that falsehoods are accepted and transmitted." English philosopher and scientist Francis Bacon (1561–1626), in the Novum Organum noted that biased assessment of evidence drove "all superstitions, whether in astrology, dreams, omens, divine judgments or the like". He wrote: The human understanding when it has once adopted an opinion ... draws all things else to support and agree with it. And though there be a greater number and weight of instances to be found on the other side, yet these it either neglects or despises, or else by some distinction sets aside or rejects[.] In the second volume of his The World as Will and Representation (1844), German philosopher Arthur Schopenhauer observed that "An adopted hypothesis gives us lynx-eyes for everything that confirms it and makes us blind to everything that contradicts it." I know that most men—not only those considered clever, but even those who are very clever, and capable of understanding most difficult scientific, mathematical, or philosophic problems—can very seldom discern even the simplest and most obvious truth if it be such as to oblige them to admit the falsity of conclusions they have formed, perhaps with much difficulty—conclusions of which they are proud, which they have taught to others, and on which they have built their lives. Wason's research on hypothesis-testing The term "confirmation bias" was coined by English psychologist Peter Wason. For an experiment published in 1960, he challenged participants to identify a rule applying to triples of numbers. At the outset, they were told that (2,4,6) fits the rule. Participants could generate their own triples and the experimenter told them whether or not each triple conformed to the rule. While the actual rule was simply "any ascending sequence", the participants had a great deal of difficulty in finding it, often announcing rules that were far more specific, such as "the middle number is the average of the first and last". The participants seemed to test only positive examples—triples that obeyed their hypothesized rule. For example, if they thought the rule was, "Each number is two greater than its predecessor," they would offer a triple that fit this rule, such as (11,13,15) rather than a triple that violates it, such as (11,12,19). Wason accepted falsificationism, according to which a scientific test of a hypothesis is a serious attempt to falsify it. He interpreted his results as showing a preference for confirmation over falsification, hence the term "confirmation bias".[Note 3] Wason also used confirmation bias to explain the results of his selection task experiment. In this task, participants are given partial information about a set of objects, and have to specify what further information they would need to tell whether or not a conditional rule ("If A, then B") applies. It has been found repeatedly that people perform badly on various forms of this test, in most cases ignoring information that could potentially refute the rule. Klayman and Ha's critique A 1987 paper by Joshua Klayman and Young-Won Ha argued that the Wason experiments had not actually demonstrated a bias towards confirmation. Instead, Klayman and Ha interpreted the results in terms of a tendency to make tests that are consistent with the working hypothesis. They called this the "positive test strategy". This strategy is an example of a heuristic: a reasoning shortcut that is imperfect but easy to compute. Klayman and Ha used Bayesian probability and information theory as their standard of hypothesis-testing, rather than the falsificationism used by Wason. According to these ideas, each answer to a question yields a different amount of information, which depends on the person's prior beliefs. Thus a scientific test of a hypothesis is one that is expected to produce the most information. Since the information content depends on initial probabilities, a positive test can either be highly informative or uninformative. Klayman and Ha argued that when people think about realistic problems, they are looking for a specific answer with a small initial probability. In this case, positive tests are usually more informative than negative tests. However, in Wason's rule discovery task the answer—three numbers in ascending order—is very broad, so positive tests are unlikely to yield informative answers. Klayman and Ha supported their analysis by citing an experiment that used the labels "DAX" and "MED" in place of "fits the rule" and "doesn't fit the rule". This avoided implying that the aim was to find a low-probability rule. Participants had much more success with this version of the experiment. In light of this and other critiques, the focus of research moved away from confirmation versus falsification to examine whether people test hypotheses in an informative way, or an uninformative but positive way. The search for "true" confirmation bias led psychologists to look at a wider range of effects in how people process information. Confirmation bias is often described as a result of automatic, unintentional strategies rather than deliberate deception. According to Robert Maccoun, most biased evidence processing occurs through a combination of both "cold" (cognitive) and "hot" (motivated) mechanisms. Cognitive explanations for confirmation bias are based on limitations in people's ability to handle complex tasks, and the shortcuts, called heuristics, that they use. For example, people may judge the reliability of evidence by using the availability heuristic—i.e., how readily a particular idea comes to mind. It is also possible that people can only focus on one thought at a time, so find it difficult to test alternative hypotheses in parallel. Another heuristic is the positive test strategy identified by Klayman and Ha, in which people test a hypothesis by examining cases where they expect a property or event to occur. This heuristic avoids the difficult or impossible task of working out how diagnostic each possible question will be. However, it is not universally reliable, so people can overlook challenges to their existing beliefs. Motivational explanations involve an effect of desire on belief, sometimes called "wishful thinking". It is known that people prefer pleasant thoughts over unpleasant ones in a number of ways: this is called the "Pollyanna principle". Applied to arguments or sources of evidence, this could explain why desired conclusions are more likely to be believed true. According to experiments that manipulate the desirability of the conclusion, people demand a high standard of evidence for unpalatable ideas and a low standard for preferred ideas. In other words, they ask, "Can I believe this?" for some suggestions and, "Must I believe this?" for others. Although consistency is a desirable feature of attitudes, an excessive drive for consistency is another potential source of bias because it may prevent people from neutrally evaluating new, surprising information. Social psychologist Ziva Kunda combines the cognitive and motivational theories, arguing that motivation creates the bias, but cognitive factors determine the size of the effect. Explanations in terms of cost-benefit analysis assume that people do not just test hypotheses in a disinterested way, but assess the costs of different errors. Using ideas from evolutionary psychology, James Friedrich suggests that people do not primarily aim at truth in testing hypotheses, but try to avoid the most costly errors. For example, employers might ask one-sided questions in job interviews because they are focused on weeding out unsuitable candidates. Yaacov Trope and Akiva Liberman's refinement of this theory assumes that people compare the two different kinds of error: accepting a false hypothesis or rejecting a true hypothesis. For instance, someone who underestimates a friend's honesty might treat him or her suspiciously and so undermine the friendship. Overestimating the friend's honesty may also be costly, but less so. In this case, it would be rational to seek, evaluate or remember evidence of their honesty in a biased way. When someone gives an initial impression of being introverted or extroverted, questions that match that impression come across as more empathic. This suggests that when talking to someone who seems to be an introvert, it is a sign of better social skills to ask, "Do you feel awkward in social situations?" rather than, "Do you like noisy parties?" The connection between confirmation bias and social skills was corroborated by a study of how college students get to know other people. Highly self-monitoring students, who are more sensitive to their environment and to social norms, asked more matching questions when interviewing a high-status staff member than when getting to know fellow students. Psychologists Jennifer Lerner and Philip Tetlock distinguish two different kinds of thinking process. Exploratory thought neutrally considers multiple points of view and tries to anticipate all possible objections to a particular position, while confirmatory thought seeks to justify a specific point of view. Lerner and Tetlock say that when people expect to justify their position to others whose views they already know, they will tend to adopt a similar position to those people, and then use confirmatory thought to bolster their own credibility. However, if the external parties are overly aggressive or critical, people will disengage from thought altogether, and simply assert their personal opinions without justification. Lerner and Tetlock say that people only push themselves to think critically and logically when they know in advance they will need to explain themselves to others who are well-informed, genuinely interested in the truth, and whose views they don't already know. Because those conditions rarely exist, they argue, most people are using confirmatory thought most of the time. Confirmation bias can lead investors to be overconfident, ignoring evidence that their strategies will lose money. In studies of political stock markets, investors made more profit when they resisted bias. For example, participants who interpreted a candidate's debate performance in a neutral rather than partisan way were more likely to profit. To combat the effect of confirmation bias, investors can try to adopt a contrary viewpoint "for the sake of argument". In one technique, they imagine that their investments have collapsed and ask themselves why this might happen. In physical and mental health Raymond Nickerson, a psychologist, blames confirmation bias for the ineffective medical procedures that were used for centuries before the arrival of scientific medicine. If a patient recovered, medical authorities counted the treatment as successful, rather than looking for alternative explanations such as that the disease had run its natural course. Biased assimilation is a factor in the modern appeal of alternative medicine, whose proponents are swayed by positive anecdotal evidence but treat scientific evidence hyper-critically. Confirmation bias may also cause doctors to perform unnecessary medical procedures due to pressure from adamant patients. Cognitive therapy was developed by Aaron T. Beck in the early 1960s and has become a popular approach. According to Beck, biased information processing is a factor in depression. His approach teaches people to treat evidence impartially, rather than selectively reinforcing negative outlooks. Phobias and hypochondria have also been shown to involve confirmation bias for threatening information. In politics and law Nickerson argues that reasoning in judicial and political contexts is sometimes subconsciously biased, favoring conclusions that judges, juries or governments have already committed to. Since the evidence in a jury trial can be complex, and jurors often reach decisions about the verdict early on, it is reasonable to expect an attitude polarization effect. The prediction that jurors will become more extreme in their views as they see more evidence has been borne out in experiments with mock trials. Both inquisitorial and adversarial criminal justice systems are affected by confirmation bias. Confirmation bias can be a factor in creating or extending conflicts, from emotionally charged debates to wars: by interpreting the evidence in their favor, each opposing party can become overconfident that it is in the stronger position. On the other hand, confirmation bias can result in people ignoring or misinterpreting the signs of an imminent or incipient conflict. For example, psychologists Stuart Sutherland and Thomas Kida have each argued that U.S. Navy Admiral Husband E. Kimmel showed confirmation bias when playing down the first signs of the Japanese attack on Pearl Harbor. A two-decade study of political pundits by Philip E. Tetlock found that, on the whole, their predictions were not much better than chance. Tetlock divided experts into "foxes" who maintained multiple hypotheses, and "hedgehogs" who were more dogmatic. In general, the hedgehogs were much less accurate. Tetlock blamed their failure on confirmation bias—specifically, their inability to make use of new information that contradicted their existing theories. In the paranormal One factor in the appeal of alleged psychic readings is that listeners apply a confirmation bias which fits the psychic's statements to their own lives. By making a large number of ambiguous statements in each sitting, the psychic gives the client more opportunities to find a match. This is one of the techniques of cold reading, with which a psychic can deliver a subjectively impressive reading without any prior information about the client. Investigator James Randi compared the transcript of a reading to the client's report of what the psychic had said, and found that the client showed a strong selective recall of the "hits". As a striking illustration of confirmation bias in the real world, Nickerson mentions numerological pyramidology: the practice of finding meaning in the proportions of the Egyptian pyramids. There are many different length measurements that can be made of, for example, the Great Pyramid of Giza and many ways to combine or manipulate them. Hence it is almost inevitable that people who look at these numbers selectively will find superficially impressive correspondences, for example with the dimensions of the Earth. A distinguishing feature of scientific thinking is the search for falsifying as well as confirming evidence. However, many times in the history of science, scientists have resisted new discoveries by selectively interpreting or ignoring unfavorable data. Previous research has shown that the assessment of the quality of scientific studies seems to be particularly vulnerable to confirmation bias. It has been found several times that scientists rate studies that report findings consistent with their prior beliefs more favorably than studies reporting findings inconsistent with their previous beliefs. However, assuming that the research question is relevant, the experimental design adequate and the data are clearly and comprehensively described, the found results should be of importance to the scientific community and should not be viewed prejudicially, regardless of whether they conform to current theoretical predictions. In the context of scientific research, confirmation biases can sustain theories or research programs in the face of inadequate or even contradictory evidence; the field of parapsychology has been particularly affected. An experimenter's confirmation bias can potentially affect which data are reported. Data that conflict with the experimenter's expectations may be more readily discarded as unreliable, producing the so-called file drawer effect. To combat this tendency, scientific training teaches ways to prevent bias. For example, experimental design of randomized controlled trials (coupled with their systematic review) aims to minimize sources of bias. The social process of peer review is thought to mitigate the effect of individual scientists' biases, even though the peer review process itself may be susceptible to such biases. Confirmation bias may thus be especially harmful to objective evaluations regarding nonconforming results since biased individuals may regard opposing evidence to be weak in principle and give little serious thought to revising their beliefs. Scientific innovators often meet with resistance from the scientific community, and research presenting controversial results frequently receives harsh peer review. Social psychologists have identified two tendencies in the way people seek or interpret information about themselves. Self-verification is the drive to reinforce the existing self-image and self-enhancement is the drive to seek positive feedback. Both are served by confirmation biases. In experiments where people are given feedback that conflicts with their self-image, they are less likely to attend to it or remember it than when given self-verifying feedback. They reduce the impact of such information by interpreting it as unreliable. Similar experiments have found a preference for positive feedback, and the people who give it, over negative feedback. In social media, confirmation bias is amplified by the use of filter bubbles, or “algorithmic editing”, which shows individuals information that they are more likely to agree with, while excluding opposing views. Some have argued that confirmation bias is the reason why society can never escape from filter bubbles, because individuals are psychologically hardwired to seek information that agrees with our preexisting values and beliefs. Others have further argued that the mixture of the two is degrading democracy—claiming that this “algorithmic editing” removes diverse viewpoints and information—and that unless filter bubble algorithms are removed, voters will be unable to make fully informed political decisions. - Cherry picking - Circular source - Cognitive bias mitigation - Cognitive inertia - Cognitive miser - Echo chamber (media) - False consensus effect - Filter bubble - Hostile media effect - Idée fixe (psychology) - List of biases in judgment and decision making - List of memory biases - Observer-expectancy effect - Reinforcement theory - Selective exposure theory - Selective perception - Semmelweis reflex - Woozle effect - David Perkins, a professor and researcher at the Harvard Graduate School of Education, coined the term "myside bias" referring to a preference for "my" side of an issue. (Baron 2000, p. 195) - "Assimilation bias" is another term used for biased interpretation of evidence. 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Grobman - Confirmation bias at You Are Not So Smart - Confirmation bias learning object – interactive number triples exercise by Rod McFarland for Simon Fraser University - Brief summary of the 1979 Stanford assimilation bias study – Keith Rollag, Babson College
In this video, we’re going to learn about Kepler’s laws of planetary motion. We’ll see what these laws are, we’ll learn some new terminology to help us understand them, and we’ll see how these laws help describe the motion of planets. To get started, imagine that one night you take your telescope outdoors and begin looking up into the sky. You notice a bright shining object. But when you consult your map of stars that you should be able to see, you’re not able to identify this bright light. Excited that you may be looking at something new, you begin to chart the position of this bright light as you come back night after night to observe its position. After some time, you get to the point where you wish you could predict where this bright light will appear in the sky on any given day. To be able to do that, it’ll be helpful to know something about Kepler’s laws of planetary motion. Before we discuss these laws though, let’s talk about the mathematical shapes known as “ellipses.” The way an ellipse works is you pick two points: these are called the focal points or the foci. Once you have these two points selected, here’s the rule for creating an ellipse from them. First, we draw a line from the first focus point and call that line 𝑑 one. Then, we draw a line from the second focus point to meet the end of that first line. We call this 𝑑 two. The rule to make the rest of the shape of the ellipse is that 𝑑 one plus 𝑑 two — the line segments from each one of our two foci — must be constant when they add together. This has to be true for every point along the path of the ellipse. Once an ellipse is formed this way by joining together the distances from its two foci, then it has some interesting geometry. If our two focal points 𝑓 one and 𝑓 two were located on top of one another at the origin of this coordinate system we’ve drawn, then our ellipse would form a perfect circle. But when that’s not the case — that is when 𝑓 one and 𝑓 two are not in the same location — then one of the two dimensions of that the ellipse makes will be longer than the other. Along that longer dimension, if we take half of what we can call the width of the ellipse, that’s called “the semimajor axis.” In a similar way, half of what we can call the height of the ellipse is called “the semiminor axis.” Now, we may stop to wonder, what does this have to do with planetary motion? It turns out that if we put a large mass of body such as the Sun at one of the focal points of an ellipse, then as Kepler found the planets in our solar system follow an elliptical path around that focal point centred on the sun. Kepler came up with three laws of planetary motion and this it turns out is one of them. It’s sometimes called “the law of orbits.” This law says that all planets in our solar system move in elliptical orbits with the Sun at one focus. Here’s a little bit of interesting terminology when it comes to elliptical motion around the Sun. If the planet we’re considering moves along in its orbit until it’s as close as it ever gets to the Sun, that planet is then said to be at its perihelion, where you may recognize helion as referring to the Sun. On the other hand though, if the planet in orbit was at its farthest point away from the Sun distancewise, then the planet is at what’s called its aphelion. Considering both perihelion and aphelion, it can be helpful to develop a mental way of remembering which one is the close one and which one is the farther one. Personally, when I hear “peri,” I think of a periscope — the very short optical device that is put up above water from a submarine. The shortness of the periscope helps me remember that the perihelion is the shorter of the two distances. If that mental reminder helps, then keep it and if it doesn’t, feel free to think of a different one. One last word about these terms, we see that helion refers to the fact that it’s the Sun that’s at the focal point. But of course, we could encounter an orbital situation, where it’s not the Sun that’s at the centre, but something else, for example, the Earth. If the Earth was the focal point around which our objects are rotating, then our terms changed to reflect that. The shorter distance is now called “the perigee” and the longer distance is called “the apogee.” So that’s the first law of Kepler’s three laws of planetary motion that planets in our solar system move in elliptical orbits and the Sun is at one focus of that ellipse. The second of Kepler’s three laws called the law of areas has to do with the area inside the ellipse that a planet sweeps out as it moves around its elliptical orbit. This law says that the line that connects a planet to the Sun sweeps out equal areas in equal times. So if we draw a line from our planet at one point to the Sun and then we let that planet move ahead in its orbit to a second spot where we keep our line between these two bodies, then the area inside the ellipse that this planet sweeps out over sometime — we can call that area 𝐴 sub one — is equal to the area that the planet would sweep out if we let it evolve the same amount of time as it continues on its elliptical orbit. In other words, if we let our planet move along its orbit for some particular time — we can call it 𝑡 — and we noticed that over that time an area of 𝐴 one was swept out, then if we let the planet move for another increment of the time 𝑡 and so the area that swept out was 𝐴 two, this second law says that 𝐴 one is equal to 𝐴 two. And the second law claims that this relationship holds regardless of where in its orbit our planet is — whether it’s close or far to the focus. This leads us to the third and final law of Kepler’s laws of planetary motion called the law of periods. An object’s period you’ll recall is the time it takes to move around one complete revolution. The period of a planet orbiting around the Sun will be the time it takes to move all the way round its ellipse once and return to its original location. The period for the Earth, for example, is about 365 days. To talk about the law of periods, we’ll introduce some shorthand notation for the two axes we’ve identified on this ellipse. We’re gonna refer to the semimajor axis as lowercase 𝑎 and the semiminor axis as lowercase 𝑏. Referring to a planet’s period by the symbol capital 𝑇, as a mathematical relationship, the third law of planetary motion says that the square of a planet’s period around its orbit is proportional to the cube of that orbit’s semimajor axis. In other words, if we took the semimajor axis 𝑎 and we cubed it, then that would be equal to a planet’s period 𝑇 squared multiplied by some constant factor. The way we’ve written this third law currently is a proportionality. But we can also write it as an inequality. We can say that a planet’s period squared is equal to four 𝜋 squared over the gravitational constant 𝐺 multiplied by the sum of the mass of the sun and the planet orbiting the Sun all multiplied by the semimajor axis of that planet’s orbit cubed. Oftentimes we’re able to simplify this expression further because the mass of any planet orbiting the Sun is typically much, much less than the mass of the Sun, meaning that we can approximate their sum as simply the mass of the Sun by itself. This law of periods shows us the mathematical relationship between an orbiting planet’s period and its semimajor axis 𝑎. Now, let’s get some practice with Kepler’s laws of planetary motion through an example. A satellite orbits Jupiter with an average orbital radius of 963700 kilometers and an orbital period of 3.269 days. Find the mass of Jupiter, considering a day as 864.0 times 10 to the third seconds. We’ll label this mass of Jupiter that we want to solve for capital 𝑀. And to start on our solution, we’ll recall Kepler’s third law of planetary motion. For a much smaller body orbiting a much larger one, Kepler’s third law tells us that the period of the smaller orbiting body squared is equal to four 𝜋 squared over 𝐺 the gravitational constant times the mass of the planet it’s orbiting all multiplied by the semimajor axis of the orbiting planet’s ellipse cubed. If we draw a sketch of this orbiting satellite, we have it in an elliptical orbit moving around a focus point of the planet Jupiter. We’re told the average orbital radius of this satellite as it moves throughout its elliptical path and we’re also told how long it takes for the satellite to move all the way around its orbit once — that is its period. We can call 𝑟 sub avg that average orbital radius and capital 𝑇 the period of the satellite’s orbit given as the product of 3.269 days times the number of seconds in a day. When we apply Kepler’s third law to our scenario, where capital 𝑀 the mass of Jupiter is what we want to solve for, we see that we know the period capital 𝑇 and big 𝐺 the universal gravitational constant is a known constant. We will let big 𝐺 be exactly 6.67 times 10 to the negative 11th cubic meters per kilograms second squared. This means that when it comes to our relationship to solve for the mass of Jupiter 𝑀, the only unknown is 𝑎 the semimajor axis of our elliptical orbit. But there’s a special relationship for elliptical path which says that the average distance from the path to the centre of the path at what we’ve drawn as an origin is equal to the semimajor axis of that orbit. In other words, 𝑎 the semimajor axis is equal to 𝑟 sub avg. So we now know everything in this expression except the mass value we want to solve for. We rearrange the expression so that 𝑀 is by itself on one side. When we plug in these values, we’re careful to convert our expression for 𝑎 from units of kilometers to units of meters. Entering this expression on our calculator, to four significant figures, we find that 𝑀 is equal to 6.641 times 10 to the 25th kilograms. That’s the mass of Jupiter based on these numbers. Let’s summarize now what we’ve learned about Kepler’s laws of planetary motion. In this segment, we learned some planetary ellipse terms. We learned how do identify the semimajor axis of an ellipse — sometimes identified with the letter 𝑎 — as well as the semiminor axis — sometimes identified with 𝑏. We also learned that when a planet is on an elliptical orbit with the Sun at one of its focus points, when that planet is closest to the Sun it’s said to be at its perihelion and when it’s furthest away from the Sun, it’s said to be at its aphelion. And we noted that the suffix helion specifically refers to a Sun-centred orbit. We also learned about Kepler’s three Laws of planetary motion. The first of which is called the law of orbits and this says that all planets move in elliptical orbits with the Sun at one focus. This law of course is based on observations of our own solar system. The second law called the law of areas says that a line connecting a planet with the Sun sweeps out equal areas in equal amounts of time passing. And finally, we learned the law of periods. This law states that if the period of a planet 𝑇 is squared, the net value is proportional to the cube of the orbit’s semimajor axis 𝑎. and we also saw this law can be expanded on into an equation that 𝑇 squared is equal to four 𝜋 squared all divided by the universal gravitational constant multiplied by the mass of the planet being orbited — often the Sun — all times the cube of the semimajor axis of the planet’s orbit. These three laws of planetary motion are strongly geometric laws and are often easiest to understand when we have a drawing of a planetary ellipse in front of us.
Teacher support for Maths Hamilton has a range of additional reference and advice materials for Maths. New Curriculum Maths Support Example Calculation Policy Addition and Subtraction Methods Multiplication and Division Methods Key Skills to Go to the Wall for Maths Challenges KS1 (answers) Maths Challenges LKS2 (answers) Maths Challenges UKS2 (answers) Hamilton Education sells hard copy teaching resources that support Hamilton plans at very low cost. Group Readers, phonics books, number lines and 'Five Minute Fillers' can help you teach literacy and numeracy skills in your classroom. These plans cover the statutory objectives of the National Curriculum for England for Year 2 and Year 3. The Coverage Chart shows you where. The Medium Term Plan lists each week's teaching focus, activities, starter and National Curriculum outcomes cross-referenced to the Hamilton Assessment Plan. These are organised as much as possible congruently so that you are addressing the same objectives with both year groups. The Outcomes Sheets allow you to record quick day-to-day judgements about children's mastery of objectives in the back of their maths books. Answers to exercises appear at the end of each week's resources document. For Homework, Problem-solving Investigations, Starters or NNS-examples select Year 2 or Year 3 on the red bar above. Year 2: Mark 2-digit numbers on a beaded line, then landmarked line. Order/compare numbers to 100. Say a number between neighbouring pairs of multiples of ten. Count on in tens and back again. Make sensible estimates. Partition 2-digit numbers; Use place value to add and subtract. Year 3: Place two and 3-digit numbers on a line. Understand place value in, order and compare 3-digit numbers. Use place value to add and subtract. Year 2: Partition numbers to 10, then 20 into pairs, record related addition sentences and corresponding subtraction facts.;Recognise the use of a symbol such as ■ to represent an unknown; Add/subtract a single digit to/from a 2-digit number not crossing 10s, using number facts and pattern. Add three small numbers. Year 3: Objectives: Know number bonds to 20 and use them in addition and subtraction; Use = to represent equality; Add and subtract 1-digit numbers to/from 2-digit numbers. Includes bar model examples. Year 2: Recognise all coins. Find totals up to 20p and change from 20p. Find all possibilities by making an ordered list. Use pairs to ten to find the complement to the next multiple of ten. Year 3: Understand and use place value with money using £ and p notation. Subtract pairs of 2-digit numbers by counting up. Find change from £1. Includes bar model examples. Year 2: Read the time to the quarter of an hour on digital and analogue clocks. Begin to identify time intervals. Identify left and right, recognise right angles, whole, half and quarter turns, both clockwise and anticlockwise. Year 3: Tell the time to five minutes using analogue, digital and Roman numeral clocks. Understand am and pm times. Understand angles as degrees of turn, right angles as quarter turns, clockwise and anticlockwise. Recognise that two right angles make a half-turn, three make three quarters of a turn and four a complete turn. Year 2: Count on in tens from any single-digit number then any number, and back again, relating this to finding 10 more/less. Add and subtract 10, 20, 11 and 21. Year 3: Add pairs of 2-digit numbers by partitioning. Use place value in money to add and subtract; Add/subtract 1, 10 and 100 to/from any 3-digit number. Year 2: Count in 10s from any number. Recognise multiples of 10. Begin to use multiplication. Count in 2s. Recognise odd and even numbers. Find halves and quarters of shapes. Year 3: Know × and ÷ facts for 2, 5 and 10 times tables. Understand multiplication is commutative. Recognise multiples of 2, 5 and 10. Understand concept of a fraction of a shape and quantity. Find ½, 1/3 and ¼ of quantities (whole number answers). Halve odd numbers. Includes bar model examples. Year 2: Find doubles to double 20 and corresponding halves. Add/subtract a single digit number to/from a 2-digit number by bridging multiples of ten using knowledge of pairs to ten and place value. Year 3: Double 2-digit numbers and halve even 2-digit numbers. Find fractions of a quantity: ½, ⅓, ¼, ¾, ⅔. Includes bar model examples. Year 2: Know pairs with a total of 20 and derive the subtraction facts. Recognise the use of a symbol such as ■ to represent an unknown. Use pairs to ten to find the complement to the next multiple of ten. Find change from 20p. Begin to find a difference between two numbers either side of a multiple of 10. Year 3: Know pairs of multiples of 5 and find other pairs of 2-digit numbers totalling 100. Subtract numbers on either side of 100 by counting up. Includes bar model examples. Year 2: Measure the length of objects using standard units. Estimate, measure and compare capacities, using suitable non-standard and standard units (litres). Year 3: Estimate, measure and convert lengths in cm and m, begin to measure in millimetres. Represent and interpret data in tables and bar charts; Understand and use place value in money, writing amounts in pounds and pence, adding and subtracting pounds, 10ps and 1ps, e.g. £4.63 – 60p and £3.49 + 30p. Year 2: Mental addition and subtraction using place value and near multiples: Add & subtract 20, 30, 40, 50 to/from two-digit numbers. Add 11, 12, 13, 21, 22, 23, 31, 32 & 33 to two-digit numbers. Begin to subtract 11, 12, 21 & 22 from two-digit numbers. Year 3: Know multiplication facts for the 3 and 4 times tables up to the 12th multiple, derive corresponding division facts. Divide by 2, 3, 4, 5 and 10, including giving remainders Year 2: Add 2-digit numbers by counting on in 10s and 1s. Add near multiples of 10 by adding 10s and adjusting. Identify and test patterns. Year 3: Use place value to add and subtract 1s, 10s, 100s to/from 2 and 3-digit numbers. Add and subtract near multiples of 10 to/from 3-digit numbers. Request new password
A team of NASA scientists have found a novel way to measure biodiversity in Alaska. By combining satellite data with water samples containing fish DNA, they can locate the habitats of native fish in the arctic over a wide area very efficiently. This information helps organizations like the federal Bureau of Land Management make more informed decisions on how to protect fish species and their ecosystems from threats from human development and a changing climate. The NASA team examined fish habitats in the roughly 23-million-acre National Petroleum Reserve in Alaska — an area both rich in native fish populations and in oil and gas. They created maps that predict how likely it is for each fish species to appear in different parts of a stream by looking at satellite and remote sensing data on landscape characteristics like vegetation “greenness” and water temperatures. Then, they combined that data with data taken from the water that showed the locations of species of fish. The project is so promising that the Bureau of Land Management already plans to expand use of this tool to cover other parts of Alaska, and the NASA team is working on a similar project to monitor amphibians along the California coast. Learn more about how this project uses NASA satellite data to monitor and protect native fish species in the story, Satellite Data Meets Cellular DNA for Species of Interest.
Kantian philosophy was the basis on which the structure of Marxism was built. It was developed by Georg Wilhelm Friedrich Hegel. Hegel's dialectical method was taken up by Karl Marx. It was an extension of the method of reasoning by antinomies that Kant used. Hegel was the most prominent philosopher in Germany. His views were widely taught. His students were divided into right-wing and left-wing Hegelians. The right-wing Hegelians offered a conservative interpretation of his work. They emphasized the compatibility between Hegel's philosophy and Christianity. They were orthodox. The left-wing Hegelians moved to an atheistic position. The group included Ludwig Feuerbach, Bruno Bauer, Friedrich Engels and Marx himself. Marx's view of history, is known as historical materialism. Hegel explained that this progressive unfolding of the Absolute involves gradual, evolutionary accretion. Hegel strongly opposed slavery in the United States during his lifetime and envisioned a time when Christian nations would radically eliminate it from their civilization. Marx accepted this broad conception of history. Hegel was an idealist and Marx sought to rewrite dialectics in materialist terms. He summarized the materialistic aspect of his theory of history in the 1859 preface to A Contribution to the Critique of Political Economy: Marx emphasized that social development sprang from the inherent contradictions within material life and the social superstructure. This notion is often understood as a simple historical narrative, Primitive communism had developed into slave states. Slave states had developed into feudal societies. Those societies in turn became capitalist states and those states would be overthrown by the self-conscious portion of their working class, or proletariat, creating the conditions for socialism and ultimately a higher form of communism. Marx did not study directly with Hegel, but after Hegel's death he studied under one of Hegel's pupils, Bruno Bauer, a leader of the circle of Young Hegelians to whom Marx attached himself. However, Marx and Engels came to disagree with Bauer and the rest of the Young Hegelians about socialism and also about the usage of Hegel's dialectic. Marx's early writings are a response towards Hegel, German idealism. Marx stood Hegel on his head in his own view of his role by turning the idealistic dialectic into a materialistic one in proposing that material circumstances shape ideas instead of the other way around. Marx was following the lead of Feuerbach. His theory of alienation, developed in the Economic and Philosophical Manuscripts of 1844 (published in 1932), inspired itself from Feuerbach's critique of the alienation of man in God. Marx criticized Feuerbach for being insufficiently materialistic. Marx began with the totality of social relations: labour, language and all which constitute our human existence. He claimed that individualism was an essence the result of commodity fetishism or alienation. In one of his first works, The Holy Family, Marx said: “Not only does Proudhon write in the interest of the proletarians, he is himself a proletarian, an ouvrier. His work is a scientific manifesto of the French proletariat”. Marx disagreed with Proudhon's anarchism. Marx wrote The Poverty of Philosophy as a refutation of Proudhon's The Philosophy of Poverty (1847). Marx's revision of Hegelianism was also influenced by Engels' 1845 book, The Condition of the Working Class in England led Marx to conceive of the historical dialectic in terms of class conflict and to see the modern working class as the most progressive force for revolution. In late November 1859, Engels acquired one of the first 1,250 copies of Charles Darwin's The Origin of Species and then he sent a letter to Marx telling: “Darwin, by the way, whom I'm just reading now, is absolutely splendid”. The following year, Marx wrote back to his colleague telling that this book contained the natural-history foundation of the historical materialism viewpoint. Marx wrote that Darwin's work is most important and suits his purpose that it provided a basis in natural science for the historical class struggle. In 1863, he quoted Darwin again within his Theories of Surplus Value (2:121), saying: “In his splendid work, Darwin did not realize that by discovering the 'geometrical progression' in the animal and plant kingdom, he overthrew Malthus theory”. Marx was influenced by classical materialism, especially Epicurus (to whom Marx dedicated his thesis “Difference of Natural Philosophy Between Democritus and Epicurus”, 1841) for his materialism. The basic difference is in Marx's thought system there is no place of Idea. Matter is everything. Hegel emphasizes the concept of Idea, but Marx talks about matter. … In Hegel's opinion Idea is of first importance because it arises at first and matter is of secondary importance. Marx accepts this process of evolution made by Hegel. He basically differed that in thought system there is no place of Idea. Matter is everything. In Hegel’s opinion Idea is of first importance because it arises at first and matter is of secondary importance. Hegel emphasizes the concept of Idea, but Marx talks about matter. This is materialism. Marx accepted the concept of dialectic from Hegel and applied it to the explanation of society. He also said that dialectic was also the clue to progress but this progress is not history and the culmination of progress is neither history nor Absolute Idea not even the National State of Germany. Hegel had simply interpreted the history dialectically but he did not suggest how to change the history as well as society. In Marx’s view, function of philosophy was not to interpret the world, but to change it. Marx applied dialectic to “justify” the proletarian revolution and radicalism. Hegel idealized the state through dialectical method and ultimately it culminated to fascism. Marx’s application of dialectic led to the proletarian revolution and establishment of communism. Marx had no interest in metaphysics. Metaphysics is essentially an abstract way of thinking. Idea and metaphysics failed to allure Marx. To him matter was of primary importance. Both Marx and Engels had admitted that Hegelian dialectics had both idealistic and revolutionary aspects. Marx and Engels accepted the latter. Marx and Engels have converted Hegelian dialectics into materialist dialectics. This is not only a method but also a theory. This is a theory of development of the most general laws of development of nature, society and knowledge. Marxist method is materialist as well as dialectical. In Marxism, dialectics and materialism are not separate from each other. Marx expressed his indebtedness to Hegel in regard to dialectics but simultaneously he categorically stated his differences with Hegelian dialectics. Let us quote few lines from his Capital: “My dialectic method is not only different from the Hegelian, but is its direct opposite. To Hegel the life process of human brain, i.e., the process of thinking, which under the name of idea he even transforms into an independent subject, is the demiurges of the real world, and the real world is only the external, phenomenal form of the idea. With me, on the contrary the idea is nothing else than the material world reflected by the human mind and translated into forms of thought.” Thus Marx agreed with the dialectics of Hegel but disagreed with the mystifying aspect. In the thoughts of both Hegel and Marx there are seeds of revolution. For the first time Hegel pointed out that history is always in movement. It never stands at a particular pointer stage. Its movement is dialectical. “He insisted that it is not simply a bare sequence of events, but a gradual process of unfolding”. According to Marx the society also progresses and the method is dialectic. In the process of progress the latter stage is different from the former. Marx also said that the latter stage is developed from the former. Both Hegel and Marx insisted that there was reason behind the dialectical process and it is not guided and motivated by any external or any other force. © C.R Nanda Academy is a Facebook Page aspiring to impart legal knowledge to Indian Citizens.
Anatomical terms of motion \|This article is part of a series on\| Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative to the anatomical position of the joints. Anatomists use a unified set of terms to describe most of the movements, although other, more specialized terms are necessary for describing the uniqueness of the movements such as those of the hands, feet, and eyes. In general, motion is classified according to the anatomical plane it occurs in. Flexion and extension are examples of angular motions, in which two axes of a joint are brought closer together or moved further apart. Rotational motion may occur at other joints, for example the shoulder, and are described as internal or external. Other terms, such as elevation and depression, refer to movement above or below the horizontal plane. Many anatomical terms derive from Latin terms with the same meaning. - 1 Classification - 2 General motion - 3 Special motion - 4 See also - 5 Notes - 6 References - 7 Sources - 8 External links Motions are classified after the anatomical planes they occur in, although movement is more often than not a combination of different motions occurring simultaneously in several planes. Motions can be split into categories relating to the nature of the joints involved: - Gliding motions occur between flat surfaces, such as in the intervertebral discs or between the carpal and metacarpal bones of the hand. - Angular motions occur over synovial joints and causes them to either increase or decrease angles between bones. - Rotational motions move a structure in a rotational motion along a longitudinal axis, such as turning the head to look to either side. Apart from this motions can also be divided into: - Linear motions (or translatory motions), which move in a line between two points. A rectilinear motion refers to a motion in a straight line between two points, whereas a curvilinear motion refers to a motion following a curved path. - Angular motions (or rotary motions) occur when an object is around another object increasing or decreasing the angle. The different parts of the object do not move the same distance. Examples include a movement of the knee, where the lower leg changes angle compared to the femur, or movements of the ankle. The prefix hyper- is sometimes added to describe movement beyond the normal limits, such as in hypermobility, hyperflexion or hyperextension. The range of motion describes the total range of motion that a joint is able to do. For example, if a part of the body such as a joint is overstretched or "bent backwards" because of exaggerated extension motion, then it can be described as hyperextended. Hyperextension increases the stress on the ligaments of a joint, and is not always because of a voluntary movement. It may be a result of accidents, falls, or other causes of trauma. It may also be used in surgery, such as in temporarily dislocating joints for surgical procedures. These are general terms that can be used to describe most movements the body makes. Most terms have a clear opposite, and so are treated in pairs. Flexion and extension Flexion describes a bending movement that decreases the angle between a segment and its proximal segment. For example, bending the elbow, or clenching a hand into a fist, are examples of flexion. When sitting down, the knees are flexed. When a joint can move forward and backward, such as the neck and trunk, flexion refers to movement in the anterior direction. Flexion of the shoulder or hip refers to movement of the arm or leg forward. Extension is the opposite of flexion, describing a straightening movement that increases the angle between body parts. When a joint can move forward and backward, such as the neck and trunk, extension refers to movement in the posterior direction. For example, when standing up, the knees are extended. Extension of the hip or shoulder moves the arm or leg backward. When the chin is against the chest, the head is flexed, and the trunk is flexed when a person leans forward. Abduction and adduction Abduction and adduction refer to motions that move a structure away from or towards the centre of the body. The centre of the body is defined as the midsagittal plane. These terms come from the Latin words with the same meaning.[b] Abduction refers to a motion that pulls a structure or part away from the midline of the body. In the case of fingers and toes, it refers to spreading the digits apart, away from the centerline of the hand or foot. Abduction of the wrist is also called radial deviation. For example, raising the arms up, such as when tightrope-walking, is an example of abduction at the shoulder. When the legs are splayed at the hip, such as when doing a star jump or doing a split, the legs are abducted at the hip. Adduction refers to a motion that pulls a structure or part toward the midline of the body, or towards the midline of a limb. In the case of fingers and toes, it refers to bringing the digits together, towards the centerline of the hand or foot. Adduction of the wrist is also called ulnar deviation. Dropping the arms to the sides, or bringing the knees together, are examples of adduction. Ulnar deviation is the hand moving towards the ulnar styloid (or, towards the pinky/fifth digit). Radial deviation is the hand moving towards the radial styloid (or, towards the thumb/first digit). (See: https://o.quizlet.com/uDf07L6r7LRa.H4VxXXziQ_m.jpg for appropriate image) Elevation and depression The terms elevation and depression refer to movement above and below the horizontal. They derive from the Latin terms with the same meaning[c] Rotation of body parts is referred to as internal or external, referring to rotation towards or away from the center of the body. Internal rotation (or medial rotation) refers to rotation towards the axis of the body. External rotation (or lateral rotation) refers to rotation away from the center of the body. - Anterograde and Retrograde flow, refers to movement of blood or other fluids in a normal (anterograde) or abnormal (retrograde) direction. - Circumduction refers to a conical movement of a body part, such as a ball and socket joint or the eye. Circumduction is a combination of flexion, extension, adduction and abduction. Circumduction can be best performed at ball and socket joints, such as the hip and shoulder, but may also be performed by other parts of the body such as fingers, hands, feet, and head. For example, circumduction occurs when spinning the arm when performing a serve in tennis or bowling a cricket ball. - Reduction refers to a motion returning a bone to its original state, such as a shoulder reduction following shoulder dislocation, or reduction of a hernia. The swinging action made during a tennis serve is an example of circumduction Special motions of the hands and feet Flexion and extension of the foot Dorsiflexion and plantar flexion refers to extension or flexion of the foot at the ankle. These terms refer to flexion between the foot and the body's dorsal surface, considered the front of the leg, and flexion between the foot and the body's plantar surface, considered the back of the leg. These terms are used to resolve confusion, as technically extension of the joint refers to dorsiflexion, which could be considered counter-intuitive as the motion reduces the angle between the foot and the leg. Dorsiflexion where the toes are brought closer to the shin. This decreases the angle between the dorsum of the foot and the leg. For example, when walking on the heels the ankle is described as being in dorsiflexion. Plantar flexion is the movement which decreases the angle between the sole of the foot and the back of the leg. For example, the movement when depressing a car pedal or standing on the tiptoes can be described as plantar flexion. A ballerina, demonstrating plantar flexion of the feet. Flexion and extension of the hand Palmarflexion and dorsiflexion refer to movement of the flexion (palmarflexion) or extension (dorsiflexion) of the hand at the wrist. These terms refer to flexion between the hand and the body's dorsal surface, which is the back of the arm, and flexion between the hand and the body's plantar surface, which in anatomical position is considered the anterior side of the arm. The direction of terms are opposite to those in the foot because of embryological rotation of the limbs in opposite directions. Pronation and supination Pronation (//) and supination (//) refer most generally to assuming prone or supine positions, but often they are used in a specific sense referring to rotation of the forearm or foot so that in the standard anatomical position the palm or sole is facing anteriorly (supination) or posteriorly (pronation). Pronation at the forearm is a rotational movement where the hand and upper arm are turned inwards. Pronation of the foot refers to turning of the sole outwards, so that weight is borne on the medial part of the foot. Inversion and eversion Inversion and eversion refer to movements that tilt the sole of the foot away from (eversion) or towards (inversion) the midline of the body. Eversion is the movement of the sole of the foot away from the median plane. Inversion is the movement of the sole towards the median plane. For example, inversion describes the motion when an ankle is twisted. Special motions of the eyes Unique terminology is also used to describe the eye. For example: - A version is an eye movement involving both eyes moving synchronously and symmetrically in the same direction. - Torsion refers to eye movement that affects the vertical axis of the eye, such as the movement made when looking in to the nose. Special motions of the jaw and teeth - Occlusion refers to motion of the mandibula towards the maxilla making contact between the teeth. - Protrusion and Retrusion are sometimes used to describe the anterior (protrusion) and posterior (retrusion) movement of the jaw. Other terms include: - Nutation and counternutation[d] refer to movement of the sacrum defined by the rotation of the promontory downwards and anteriorly, as with lumbar extension (nutation); or upwards and posteriorly, as with lumbar flexion (counternutation). - Opposition refers to the movement that involves grasping of the thumb and fingers. - Protraction and Retraction refer to an anterior (protraction) or posterior (retraction) movement, such as of the arm at the shoulders, although these terms have been criticised as non-specific. - Reciprocal motion refers to alternating motions in opposing directions. - Reposition refers to restoring an object to its natural condition. - Anatomical terms of location - Anatomical terms of muscle - Anatomical terms of bone - Anatomical terms of neuroanatomy - Marieb 2010, p. 212. - Lippert 2011, pp. 6-7. - Kendall 2005, p. 57. - Lippert 2011, pp. 1-7. - Kendall 2005, p. G-4. - Seeley 1998, p. 229. - "Anatomy & Physiology". Openstax college at Connexions. Retrieved November 16, 2013. - OED 1989, "flexion", "extension". - OED 1989, "flexion". - Kendall 2005, p. 56. - Cook 2012, pp. 180-193. - OED 1989, "extension". - Swartz 2010, pp. 590–591. - OED 1989, "adduction", "abduction", "abduct". - OED 1989. - OED 1989, "elevation". - Kendall 2005, p. 303. - OED 1989, "depression". - Swartz 2010, pp. 590-1. - OED 1989, "anterograde", "retrograde". - Saladin 2010, p. 300. - Kendall 2005, p. 304. - Taber 2001, "reduction". - OED 1989, "plantar flexion", "dorsiflexion". - Kendall 2005, p. 371. - Kyung 2005, p. 123. - Swartz 2010, pp. 591-593. - OED 1989, "plantarflexion", "dorsiflexion". - Swartz 2010, pp. 591–592. - OED 1989, "pronation". - OED 1989, "supination". - Swartz 2010, p. 591. - Kyung 2005, p. 108. - DMD 2012, "version". - Taber 2001, "torsion". - Taber 2001, "occlusion". - Taber 2001, "protrusion", "retrusion". - OED 1989, "nutation". - Houglum 2012, p. 333. - Taber 2001, "opposition". - OED 1989, "protraction", "retraction". - Kendall 2005, p. 302. - Taber 2001, "reciprocation". - OED 1989, "resposition". - Albert, Daniel (2012). Dorland's Illustrated Medical Dictionary. (32nd ed.). Philadelphia, PA: Saunders/Elsevier. ISBN 978-1416062578. - Chung, Kyung Won (2005). Gross Anatomy (Board Review). Lippincott Williams & Wilkins. ISBN 0-7817-5309-0. - Cook, Chad E. (2012). Orthopedic Manual Therapy: An Evidence Based Approach (2nd ed.). Upper Saddle River, NJ: Pearson Education. ISBN 978-0-13-802173-3. - Houglum, Peggy A.; Bertoli, Dolores B. (2012). Brunnstrom's Clinical Kinesiology. F. A. Davis Company. ISBN 978-0-8036-2352-1. - Kendall, Florence Peterson; [et al.]; et al. (2005). Muscles : testing and function with posture and pain (5th ed.). Baltimore, MD: Lippincott Williams & Wilkins. ISBN 0-7817-4780-5. - Lippert, Lynn S. (2011). Clinical Kinesiology and Anatomy (5th ed.). F. A. Davis Company. ISBN 978-0-8036-2363-7. - Marieb, Elaine N.; Wilhelm, Patricia B.; Mallat, Jon (2010). Human Anatomy. Pearson. ISBN 978-0-321-61611-1. - Saladin, Kenneth S. (2010). Anatomy & Physiology The Unity of Form and Function (5th ed.). McGraw Hill. ISBN 978-0077361358. - Seeley, Rod R.; Stephens, Trent D.; Tate, Philip (1998). Anatomy & Physiology (4th ed.). WCB/McGraw-Hill. ISBN 0-697-41107-9. - Simpson, John A.; Weiner, Edmung (1989). The Oxford English Dictionary. Oxford: Clarendon Press. ISBN 9780198611868. - Swartz, Mark H. (2010). Textbook of Physical Diagnosis: History and Examination (6th ed.). Saunders/Elsevier. ISBN 978-1-4160-6203-5. - Venes, Donald (Editor); Thomas, Clayton L. (Editor); Egan, Elizabeth J. (Managing Editor); Morelli, Nancee A. (Assistant Editor); Nell, Alison D. (Assistant Editor); Matkowski, Joy (2001). Taber's Cyclopedic Medical Dictionary (illustrated in full color 19th ed.). Philadelphia: F.A.Davis Co. ISBN 0-8036-0655-9. \|Wikimedia Commons has media related to Anatomical terms of motion.\|
Operations and Algebraic Thinking ⎯ 4.OA A. Use the four operations with whole numbers to solve problems. 1. Interpret a multiplication equation as a comparison, e.g., interpret 35 = 5 × 7 as a statement that 35 is 5 times as many as 7 and 7 times as many as 5. Represent verbal statements of multiplicative comparisons as multiplication equations. Number and Operations—Fractions 4.NF B. Build fractions from unit fractions by applying and extending previous understandings of operations on whole numbers. 4. Apply and extend previous understandings of multiplication to multiply a fraction by a whole number. a. Understand a fraction a/b as a multiple of 1/b. For example, use a visual fraction model to represent 5/4 as the product 5 × (1/4), recording the conclusion by the equation 5/4 = 5 × (1/4). b. Understand a multiple of a/b as a multiple of 1/b, and use this understanding to multiply a fraction by a whole number. For example, use a visual fraction model to express 3 × (2/5) as 6 × (1/5), recognizing this product as 6/5. (In general, n × (a/b) = (n × a)/b.) c. Solve word problems involving multiplication of a fraction by a whole number, e.g., by using visual fraction models and equations to represent the problem. For example, if each person at a party will eat 3/8 of a pound of roast beef, and there will be 5 people at the party, how many pounds of roast beef will be needed? Between what two whole numbers does your answer lie? NOTE: Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.
This challenge but with a better spec. Your program will take a linear equation containing a single variable x and output the value of Input / Parsing - The input will only contain numbers, operators, parenthesis ( x, and an =sign (this means no whitespace). - Parenthesis will always be balanced. - There will always be at least 1 xmay be preceded by a number. - All equations will exactly have one result. A number can be defined by following these steps. A number can be defined by the regex: If you don't speak regex: A digit is defined as - It may have a -at the beginning of it signifying negative - Then there may be some digits. If they aren't any digits there will be a decimal point - If a decimal point exists, at least one digit will follow it The biggest a number / value will be is defined by your language's capabilities. An operator is any of: +-/, they will always appear between numbers, and or parenthesis (5)(5) is not a valid input for the sake of simplicity. Parenthesis will always contain a valid expression (a valid combination of numbers and/or operators) inside them. "Balanced" parenthesis is defined as every ( will have an associated closing - Order of operations should be followed and the precedences are (highest to lowest): - Parenthesis (most deeply nested first) - Multiplication & Division - Addition & Subtraction - If two operators with the same precedence are occurred you should prefer going left -> right You should output the result in some way. If you don't output just number result, clarify in your answer how the output is outputted. Your output format should be consistent. Output may be a decimal, but it will always be rational, the precision is limited to your language's precision. Only if your language does not support floating point arithmetic, you do not need to support it. - Built-ins trivializing this task are allowed but, you must clearly add [uses built-in]clearly to the header of the answer. This exempts your answer from winning - A "Built-ins trivializing this task" is any of: - Something which takes in an equation and outputs the value for a/the variable - Something which will completely simplify an equation evalor a related function to do a significant amount of the parsing. Use of evaland related functions are disallowed if they are used to (with minimal modification to the input) solve linear equations. - If you're in doubt, just ask in a comment. - Built-ins which parse the equation are allowed 3+4=x 7 4+x=5 1 3+33=x 12 3x-4=7+2x 11 3--1=x 4 3*(2+4x)=7x-4 -2 1.2+2.3x=5.8 2 10=4x 2.5 (5)(4)=x no operator between (5) and (4) 5(x+3)=2 no operator 5 and (...) x=y the only variable is x 4=3 there is no x x+3=x-7 no solution x=x infinite solutions +5=x + is not an unary operator. -5=x would be valid though 1/(x-3)=5 Nonlinear 3/x Nonlinear
Copernicus’s discovery that the Earth revolves around the sun was a huge shift in how we think about our place in the universe. Before this, it was widely believed that the Earth was the center of the universe. So, when Johannes Kepler proposed his three laws of planetary motion, which said that planets orbit the sun in elliptical orbits, it was a completely new way of thinking about the solar system. The three Kepler Laws about the motion of planetary objects are as follows: The orbit of a planet is an ellipse, with the Sun at one focus point. A planet sweeps out equal areas in its orbit over equal periods. The square of a planet's orbital period is proportional to the cube of its average distance from the Sun. These laws explain the motion of planets in our Solar System. They also provide a foundation for understanding Newton's Laws of Motion, which govern the motion of all objects in the Universe. In astrophysics, Kepler's laws serve as a base and hold a very prominent position. You may need to include this topic in your course contents if you are planning to teach an advanced physics course. Image from Labster's Kepler Laws simulation. Some students may find these three laws a bit tricky to understand. Read on to learn three reasons why Kepler's laws can be hard and five ways to teach them effectively. 3 Reasons Why Students Find Kepler Laws tricky Laws are abstract and their statements can be sometimes hard for students to digest. Here are three reasons why Kepler's laws can be hard for students. 1. It’s Abstract Since this law explains the motion of celestial bodies, it seems abstract for students. As these bodies move in outer space; you cannot show them to the students. This makes it hard for them to visualize. 2. Students find no Relevance in the Real World Kepler's laws apply to planetary motion and celestial bodies. Many students find it difficult to see how these laws are relevant to their everyday lives. They may wonder why they need to learn about something that seems so abstract and theoretical. 3. The Math is Tricky To understand Kepler's laws, students need to be comfortable with basic algebra and geometry. The equations can be complicated, and some students may find them difficult to follow. 5 Ways to Make Kepler Laws an Approachable Keeping in view some difficulties faced by students, here are five ways to make Kepler's Laws more approachable topic. 1. Tell Them the Exciting Life story of Kepler and Tycho Laws can be quite boring for students and that’s because students think of them as a piece of information they have to memorize. However, to make things interesting and get them energized you can take start with a story. The story can be about the scientist who put forward this law or about an incident that led him to propose that conclusion. For instance, in this case, you can tell students about Tycho Brahe and Johannes Keppler. Johannes Keppler though proposed the three laws but he would haven’t done without Tycho’s observational data. Tycho Brahe was a rich Danish astronomer with an extravagant laboratory in Denmark. He was from a noble family and therefore received thorough formal education. He was one of the last astronomers to work without a telescope. However, he had developed instruments to accurately take measurements, and his observational data was highly valued at that time. Kepler was a German astronomer who unlike Brahe didn’t belong to any noble family. He was quite religious and a strong believer in Copernican theory. When Kepler was 27, he became an assistant to Brahe, who asked him to work on the orbit of Mars. Brahe and Kepler had two different personalities and Brahe was much superior to Kepler. Initially, they had trouble working together. However, the sudden death of Brahe in 1601 proved to be a blessing in disguise for Kepler; he became an imperial Mathematician and got access to Brahe’s data. He struggled for the first two years with Brahe’s data, however, he got a breakthrough with these two laws. The third law was discovered a decade later. There’s a long story on how Kepler led to the first laws; we have just presented a short version to describe how you can mention things from this perspective. 2. Use analogies to Explain Core Concepts: Sometimes it's difficult for students to understand things with technical terms. They seem new and their brains find it hard to understand the concept being conveyed through them. So, the best way to teach new theoretical laws is through analogies. Analogies can be helpful when explaining difficult concepts. For instance, when introducing Kepler’s laws, you can say that the motion of celestial bodies is similar to the way a satellite orbits the Earth. Since the law explains the elliptical paths of space bodies, you can give examples of how elliptical orbits are found in nature, such as the way a leaf falls from a tree. You can also help students become familiar with Kepler Laws by having them create models of the Solar System that demonstrate the laws in action. This can be done with balls of different sizes (to represent the different planets) and string (to represent their orbits). By moving the balls around and watching how they interact, students can gain a better understanding of how the laws work. 3. Use Visual Aids to Explain the three Laws Physics laws usually describe natural phenomena or behavior of natural objects around us. In this case, the Kepler laws also mention the motion of celestial bodies. Now, it is not possible, even for diligent students to understand these laws without any visuals. As an educator, you will need multiple clear and concise images to explain these laws. Here are a few figures, that you can use to explain each of the three laws. Kepler’s first law states that the orbit of a planet is an ellipse, with the Sun at one focus point. (The elliptical path is just similar to a circular one, however, it’s a little stretched. ) In the figure, we can see that the path of all planets around the Sun is elliptical. But the eccentricity of this path is too small, that we confuse it with a circle. Figure from Labster explaining Kepler’s First Law The second law states that each planet sweeps out equal areas in its orbit over equal periods. This law explains the fact that a planet doesn’t move at the same speed all the time. When it is closer to the sun, it moves faster, as shown by the arc length in Area 1. But when it is away from Sun, it moves slower, as shown by the arc length of Area 2. If you look closely at the figure, you will see that planet has covered more distance in the first case, and less distance in the second case, during one month period. However, in the first case, the orbit is narrow, while in the second case, it's wider. So, the total area, despite speed variations, is the same in each case. The third law explains the relative motion of planets with respect to each other. The law states that the square of a planet's orbital period is proportional to the cube of its average distance from the Sun. In similar terms, it means that planets that are far from the Sun will take a longer time to complete their orbit around and vice versa. In the figure below, you can see that the closest planet completes more than three-fourths of its orbit in one period, whereas the end planet just covers a fractional distance after one time period. In addition to these figures, you can also use animations to explain the path of planets and their orbits. For instance, the animation below shows the orbit of a planet around the Sun. Image from Labster's Kepler Laws simulation. 4. Mention How Kepler’s Laws are Used Today Keppler’s laws are used in many fields, from astronomy to engineering. Mentioning how these laws are used in the real world can help students see their relevance. Motion of Satellites Kepler's laws are greatly applied to study the motion of planets, asteroids, and other space objects in the solar system. Today, they are being used to design and launch satellites in space. Newton got the idea from the Kepler laws and put forward his own three laws on motion and universal gravitation law. These laws are the base of modern physics. 5. Use Virtual Lab Simulations Kepler’s laws explain the movement of celestial and space bodies, which cannot be physically shown to students nor you can design any experiments around these laws. In this case, Labster virtual lab simulations can help you. At Labster, we create interactive simulations based on real-world scenarios to explain complex scientific phenomena. Students play games, make fun and learn through their interaction during the simulation. For the current case, you can check out Kepler Laws simulation, in which students get in search of life on other planets. Along the journey, they learn about the shape, and path of planets’ orbits and how their velocities change along an orbit. Find that interesting? Want to Learn More? Contact Us now and drop a message. Our experts will answer all your queries.
The central processing unit (CPU) is the brain of a computer. It is responsible for executing instructions and controlling the other components of the computer. The CPU is made up of three main components: the arithmetic logic unit (ALU), the control unit, and the memory unit. These components work together to perform calculations, manage data, and control the flow of information within the computer. Understanding these components is essential for anyone interested in computer architecture and programming. In this article, we will explore each of these components in more detail and see how they work together to make a computer run. What is a CPU? The Role of a CPU in a Computer System A Central Processing Unit (CPU) is the primary component of a computer system that performs the majority of the processing tasks. It is often referred to as the “brain” of the computer, as it is responsible for executing instructions and performing calculations. The CPU’s role in a computer system is multifaceted and crucial. It serves as the control center of the computer, managing the flow of data between various components, such as the memory, input/output devices, and secondary storage. The CPU executes the instructions contained within a program, manipulating data and performing calculations to solve problems or complete tasks. In addition to its primary responsibilities, the CPU also plays a significant role in the overall performance of the computer system. It determines the speed at which the computer can execute instructions, and its performance directly impacts the responsiveness and efficiency of the system. The CPU is also responsible for managing the allocation of resources within the computer system. It prioritizes tasks and determines the order in which they should be executed, ensuring that the system runs smoothly and efficiently. Overall, the CPU is a critical component of a computer system, and its role cannot be overstated. It is the driving force behind the system’s performance and is essential for the efficient execution of programs and tasks. Types of CPUs A CPU, or Central Processing Unit, is the primary component of a computer that performs most of the processing. It is often referred to as the “brain” of the computer, as it is responsible for executing instructions and controlling the operation of the computer. There are two main types of CPUs: RISC (Reduced Instruction Set Computing) and CISC (Complex Instruction Set Computing). RISC CPUs are designed to execute a small number of instructions very quickly, while CISC CPUs are designed to execute a large number of instructions with varying levels of complexity. Another type of CPU is the VLIW (Very Long Instruction Word) CPU, which is designed to execute multiple instructions in parallel. This allows for greater efficiency and faster processing times. Finally, there are also specialized CPUs, such as those used in gaming consoles or mobile devices, which are designed to optimize performance for specific tasks or applications. In conclusion, the type of CPU used in a computer will depend on the specific needs and requirements of the user, and can have a significant impact on the overall performance and capabilities of the system. The Three Main Components of a CPU 1. Arithmetic Logic Unit (ALU) Calculations and Logic Operations The Arithmetic Logic Unit (ALU) is a vital component of a CPU that performs mathematical calculations and logical operations. It is responsible for carrying out arithmetic operations such as addition, subtraction, multiplication, and division, as well as logical operations such as AND, OR, NOT, and XOR. These operations are essential for processing data and executing instructions in a computer system. The ALU is designed to perform these operations quickly and efficiently, using a combination of hardware and software techniques. It is typically composed of several individual circuits that are specialized for performing specific types of calculations or logical operations. For example, there may be separate circuits for performing arithmetic operations, logical operations, and bit manipulation. In addition to performing calculations and logical operations, the ALU also plays a critical role in the overall performance and efficiency of the CPU. By performing these operations quickly and efficiently, the ALU helps to ensure that the CPU can process data and execute instructions at high speeds. This is particularly important in modern computer systems, where processing power is critical for applications such as gaming, video editing, and scientific simulations. Overall, the ALU is a critical component of a CPU, responsible for performing mathematical calculations and logical operations that are essential for processing data and executing instructions. Its design and performance have a significant impact on the overall performance and efficiency of the CPU, making it a key area of focus for computer engineers and designers. 2. Control Unit (CU) The Control Unit (CU) is one of the three main components of a CPU. It is responsible for managing the flow of data and instructions within the CPU. The CU controls the sequence and coordination of operations executed by the CPU. It fetches, decodes, and executes instructions, making sure that the CPU carries out the intended operations in the correct order. Instruction Fetching and Decoding The CU is responsible for fetching instructions from memory and decoding them so that the CPU can execute them. This involves fetching the instruction from memory, decoding it to determine the operation to be performed, and preparing the operands for the operation. The CU fetches instructions one at a time, in the order they are stored in memory. Sequencing and Coordinating Operations The CU coordinates the execution of instructions within the CPU. It controls the order in which instructions are executed, ensuring that they are executed in the correct order. The CU also manages the flow of data between the CPU and memory, controlling when data is transferred to and from memory. In addition, the CU manages the allocation of resources within the CPU. It ensures that the CPU’s registers and other resources are used efficiently, and that data is stored in the appropriate locations within the CPU. The CU also manages the use of conditional instructions, allowing the CPU to execute different instructions based on the results of previous operations. Overall, the Control Unit (CU) is a critical component of the CPU, responsible for managing the flow of data and instructions within the CPU. It controls the sequence and coordination of operations executed by the CPU, fetches and decodes instructions, and manages the allocation of resources within the CPU. Primary Storage and Data Manipulation Registers serve as the primary storage and data manipulation unit within a CPU. They store data that is being actively used by the CPU and allow for quick access to this information. This allows for the CPU to perform calculations and operations on the data without having to constantly fetch it from main memory. The registers can be thought of as the CPU’s “working memory”, where data is temporarily stored and manipulated before being stored in long-term memory or used to perform calculations. Temporary Data Holding and Data Transfer In addition to their role in primary storage and data manipulation, registers also serve as temporary data holding and data transfer units. When the CPU needs to transfer data between different parts of the computer, such as between the CPU and main memory or between different CPU cores, the data is stored in registers for easy access and transfer. This allows for quick and efficient data transfer, which is crucial for the proper functioning of the CPU and the overall computer system. The registers act as a buffer between different parts of the computer, allowing for seamless data transfer and storage. Other Key Components of a CPU Temporary Storage and Data Retrieval Cache memory is a small, fast memory storage system that is used to temporarily store frequently accessed data or instructions. It is designed to reduce the average access time of a computer’s memory, thus improving the overall performance of the system. Cache memory operates on the principle of “quick access,” meaning that it stores data that is likely to be needed in the near future, making it more accessible to the CPU. Speed and Performance Enhancement Cache memory plays a crucial role in improving the speed and performance of a CPU. Since the CPU relies heavily on accessing data from memory, having a cache memory system that can quickly retrieve data reduces the amount of time the CPU has to wait for data to be fetched from main memory. This improvement in data retrieval speed translates to faster processing times and an overall increase in system performance. Additionally, cache memory is integrated into the CPU itself, allowing for quicker access to frequently used data and instructions, further boosting the CPU’s efficiency. Data Transfer and Communication The bus system is a critical component of a CPU that facilitates the transfer of data between different parts of the processor. It acts as a communication channel that allows different components to communicate with each other, thereby enabling the CPU to function efficiently. The bus system consists of two main types of buses: the system bus and the address bus. The system bus is responsible for transferring data between the CPU and other peripheral devices, such as memory, input/output (I/O) devices, and secondary storage devices. It allows the CPU to access these devices and retrieve or store data as required. The system bus is divided into several sub-buses, each of which is dedicated to a specific type of device. For example, the memory bus is used to transfer data between the CPU and the memory, while the I/O bus is used to transfer data between the CPU and I/O devices. The address bus, on the other hand, is responsible for transmitting memory addresses between the CPU and the memory. It enables the CPU to access specific locations in the memory and retrieve or store data. The address bus is also divided into several sub-buses, each of which is dedicated to a specific type of memory access. For example, the instruction bus is used to transfer instructions from the CPU to the memory, while the data bus is used to transfer data from the memory to the CPU. Synchronization and Coordination In addition to facilitating data transfer and communication, the bus system also plays a critical role in synchronizing and coordinating the activities of different components within the CPU. It ensures that all components are working together in a coordinated manner, thereby improving the overall performance of the processor. One of the key challenges in coordinating the activities of different components within the CPU is managing the timing of data transfers. The bus system achieves this by using a technique called clock synchronization. Clock synchronization involves the use of a common clock signal to synchronize the activities of different components within the CPU. By ensuring that all components are synchronized to the same clock signal, the bus system can manage the timing of data transfers and ensure that all components are working together in a coordinated manner. Another challenge in coordinating the activities of different components within the CPU is managing conflicts between different data transfers. The bus system achieves this by using a technique called bus arbitration. Bus arbitration involves the use of a bus controller to manage conflicts between different data transfers and ensure that each transfer is completed in a timely and efficient manner. By ensuring that conflicts are managed effectively, the bus system can improve the overall performance of the CPU. Factors Affecting CPU Performance Measuring Processing Power In a CPU, clock speed refers to the rate at which the processor executes instructions. It is measured in GHz (gigahertz) and determines how many instructions the CPU can process per second. A higher clock speed translates to a faster processing speed and a more powerful CPU. Limitations and Trade-offs While clock speed is a critical factor in determining CPU performance, it is not the only one. There are other factors to consider, such as the number of cores, cache size, and architecture. A higher clock speed can lead to increased power consumption and heat generation, which can limit the CPU’s lifespan and require more efficient cooling solutions. Moreover, there is a trade-off between clock speed and power efficiency. A CPU with a higher clock speed will consume more power, which can impact battery life in laptops and other portable devices. Balancing clock speed with power efficiency is essential to ensure optimal performance while minimizing energy consumption. Overall, clock speed is a crucial component of CPU performance, but it should be considered alongside other factors to achieve the best balance between processing power and power efficiency. Instruction Set Architecture (ISA) The Instruction Set Architecture (ISA) is a critical component of a CPU, as it defines the set of instructions that the processor can execute. It is the interface between the hardware and the software, and it determines how the CPU interacts with other components of the computer system. The ISA is a crucial factor that affects the performance of a CPU. Code Compatibility and Efficiency The ISA affects the compatibility and efficiency of code execution. Code compatibility refers to the ability of a CPU to execute instructions written for other processors. For example, if a program written for an Intel CPU is executed on an AMD CPU, it may not run as efficiently as it would on the Intel CPU due to differences in the ISA. This is because the instructions may not be compatible with the AMD CPU’s ISA, leading to slower execution times. On the other hand, code efficiency refers to the ability of a CPU to execute instructions quickly and efficiently. The ISA affects code efficiency because it determines the number of clock cycles required to execute each instruction. A CPU with a more efficient ISA can execute instructions faster than a CPU with a less efficient ISA, resulting in better performance. Limitations and Workarounds The ISA also has limitations that can affect the performance of a CPU. For example, some instructions may not be supported by the CPU, resulting in slower execution times or the need for workarounds. Additionally, some applications may require specific instructions that are not supported by the CPU, which can limit the performance of the application. To overcome these limitations, CPU manufacturers may implement workarounds such as emulation or translation. Emulation involves translating instructions from one ISA to another, while translation involves recompiling the code to use a different ISA. These workarounds can improve the compatibility and efficiency of code execution, but they can also introduce overhead that can negatively impact performance. In conclusion, the ISA is a critical component of a CPU that affects its performance. It determines the compatibility and efficiency of code execution, as well as the limitations and workarounds required to overcome any incompatibilities. Understanding the ISA is essential for optimizing the performance of a CPU and ensuring that it can execute code efficiently and effectively. Transistor Count and Die Size The manufacturing process of a CPU plays a crucial role in determining its performance. One of the key factors that influence the performance of a CPU is the number of transistors it contains. The transistor count directly affects the processing power of the CPU, with more transistors enabling faster and more efficient processing. In addition to transistor count, the size of the die, which is the piece of silicon on which the transistors are etched, also impacts CPU performance. A larger die size typically means more transistors and higher performance. However, a larger die size also leads to increased power consumption and heat generation, which can affect the thermal management of the CPU. Power Consumption and Thermal Management Another factor that is affected by the manufacturing process of a CPU is its power consumption. The power consumption of a CPU is determined by the number of transistors and the clock speed at which they operate. CPUs with a higher transistor count and faster clock speed require more power, which can lead to increased heat generation. Thermal management is the process of dissipating the heat generated by the CPU to prevent it from overheating. Effective thermal management is crucial for maintaining the stability and performance of the CPU. The manufacturing process can impact the thermal management of a CPU by affecting its power consumption and die size. For example, a CPU with a larger die size and higher transistor count will generate more heat, which requires more effective thermal management to prevent overheating. In summary, the manufacturing process of a CPU plays a critical role in determining its performance. Factors such as transistor count, die size, power consumption, and thermal management all impact the performance of a CPU. By understanding these factors, CPU manufacturers can optimize the manufacturing process to create CPUs that offer high performance while maintaining stability and efficiency. CPU Innovations and Future Developments Parallel Processing and Scalability The advent of multi-core processors has enabled significant advancements in parallel processing capabilities. By incorporating multiple processing cores within a single chip, these processors allow for the simultaneous execution of multiple instructions, greatly enhancing the overall performance of the CPU. As a result, multi-core processors have become a key component in modern computing systems, providing increased scalability and the ability to handle complex, multi-threaded workloads. Challenges and Limitations Despite their numerous benefits, multi-core processors also present several challenges and limitations. One of the primary issues is the complexity of effectively managing and coordinating the resources of multiple cores. Ensuring that the workload is distributed evenly across all available cores and that communication between cores is efficient can be a daunting task, particularly in large-scale systems. Another challenge lies in the design of software that can effectively utilize the parallel processing capabilities of multi-core processors. Traditional sequential algorithms may not be optimized for parallel execution, requiring developers to rewrite existing code or create new algorithms specifically designed for multi-core architectures. Additionally, power consumption and heat dissipation become increasingly important concerns as the number of cores within a processor increases. More cores generally equate to higher power consumption and heat generation, which can lead to reduced battery life in portable devices and increased cooling requirements in desktop systems. Finally, there is a practical limit to the number of cores that can be incorporated into a single processor. As the number of cores increases, the complexity of the chip and the challenges associated with coordinating and managing the individual cores also grow. This may ultimately limit the scalability of multi-core processors and lead to the development of alternative architectures in the future. Quantum computing is a rapidly evolving field that has the potential to revolutionize computing as we know it. In contrast to classical computers, which store and process information using bits that can be either 0 or 1, quantum computers use quantum bits, or qubits, which can exist in multiple states simultaneously. This property, known as superposition, allows quantum computers to perform certain calculations much faster than classical computers. Quantum computing is based on the principles of quantum mechanics, which describe the behavior of particles at the atomic and subatomic level. In a quantum computer, information is stored in quantum bits, or qubits, which can exist in multiple states simultaneously. This allows quantum computers to perform certain calculations much faster than classical computers. One of the key concepts in quantum computing is the quantum gate, which is a mathematical operation that transforms a qubit from one state to another. Quantum gates are the building blocks of quantum algorithms, which are used to solve complex problems such as factorizing large numbers and searching unsorted databases. Potential applications of quantum computing include cryptography, optimization, and simulation. For example, quantum computers could be used to crack complex encryption algorithms that are currently considered secure, or to optimize complex systems such as transportation networks and financial markets. Additionally, quantum computers could be used to simulate complex physical systems, such as the behavior of molecules in a chemical reaction. However, the development of practical quantum computers is still in its infancy, and there are many technical challenges that must be overcome before they can be widely adopted. For example, quantum computers are highly sensitive to their environment and require careful control of temperature and vibration to operate properly. Additionally, quantum computers are currently limited in the number of qubits they can store and process, which limits their practical applications. Despite these challenges, the potential of quantum computing to revolutionize computing and solve problems that are currently intractable has generated significant interest and investment from industry and academia. As researchers continue to make advances in the field, it is likely that quantum computing will play an increasingly important role in the future of computing. 1. What are the three main components in a central processing unit (CPU)? The three main components in a central processing unit (CPU) are the control unit, the arithmetic logic unit (ALU), and the memory. The control unit is responsible for managing the flow of data and instructions within the CPU, while the ALU performs mathematical and logical operations on that data. The memory stores the data and instructions that the CPU is working on, allowing the CPU to access them quickly and efficiently. 2. What is the control unit in a CPU? The control unit is a key component in a CPU that manages the flow of data and instructions within the CPU. It receives instructions from the memory and decodes them, determining what operation needs to be performed and sending the appropriate signals to the ALU and memory. The control unit also manages the timing and coordination of all the different components within the CPU, ensuring that they work together smoothly and efficiently. 3. What is the arithmetic logic unit (ALU) in a CPU? The arithmetic logic unit (ALU) is a component in a CPU that performs mathematical and logical operations on data. It receives instructions from the control unit and performs the specified operation, such as addition, subtraction, multiplication, or comparison. The ALU is an essential part of the CPU, as it allows the CPU to perform complex calculations and make decisions based on the data it processes. 4. What is the memory in a CPU? The memory in a CPU is a storage device that holds the data and instructions that the CPU is working on. It allows the CPU to access the data quickly and efficiently, which is essential for the CPU to perform its tasks. The memory is divided into different sections, such as the cache, which holds frequently used data, and the main memory, which holds larger amounts of data. The memory is an important component of the CPU, as it allows the CPU to work with large amounts of data and perform complex operations. CPU and Its Components\|\| Components of MIcroprocessor
What Is Climate? Our day-to-day experience of the Earth system is in the form of the conditions we experience at Earth’s surface. The daily conditions that we think of as weather—the temperature, presence or absence of precipitation, winds, humidity, and so on—are a snapshot of the state of the Earth system at a particular instant in time and in a particular location. The weather that we get is variable, but in Saskatchewan most people would not be surprised to experience summer days with temperatures of 20 °C to 30 °C, and winter days with temperatures between –20 °C to –30 °C. Our notion of what summers and winters are generally like reflects our understanding of Saskatchewan’s climate. If we get a day in July with a daytime high of 10 °C, that would seem like unusually cold weather because we know it is uncharacteristic of the climate over all. We characterize the climate by collecting data about the weather every day, and then calculating the average conditions over a period of decades. The Government of Canada provides averages for the periods 1961 to 1990, 1971 to 2000, and 1981 to 2010 in an online database that is searchable by geographic location or station. Data measured at Saskatoon’s Diefenbaker International Airport show that the average annual temperature from 1981 to 2010 is 0.6 °C higher than the annual average from 1961 to 1990, due warmer conditions in the winter and early spring (Figure 16.3). The climate as represented by the 1961 to 1990 interval was slightly cooler than the climate represented by the 1981 to 2010 interval. People who lived in Saskatoon between 1961 and 2010 may or may not have a sense that the weather they experienced from day to day was different for those intervals. In fact, some may have the record high of 35.3 °C on September 4, 1978 seared into their memory, and feel that Septembers just aren’t as hot as they used to be. They would be correct that as of 2017, there are no September temperatures recorded at the Diefenbaker International Airport weather station with a daytime high greater than 35.3 °C. But if that gave them the impression that Septembers are cooler on average today than in the past, that would not be consistent with the data. A climate-forcing mechanism is a process that causes climate to change. Climate forcings work by initiating changes in how heat energy moves into, through, and out of the Earth system. When we discuss a particular climate change event, the climate-forcing mechanism is what initiated the change. Feedbacks also alter climate, but we want to know what triggered the feedbacks in the first place. Climate Forcing by Changes in Insolation Insolation, or incoming solar radiation, refers to how much of the sun’s energy reaches Earth’s surface in a given period of time. Insolation is measured in Watts per square meter (W/m2). Long-term Solar Evolution Over the long term (billions of years), stars like our sun become larger, brighter, and hotter (Figure 16.4). Earth receives 40% more heat from the sun today than it did 4.5 billion years ago. In Figure 16.4, the blue Now arrow shows the sun’s current point in its life history. Although the blue arrow appears to indicate an instant in time, the time interval reflecting the duration of human existence on Earth is but a tiny fraction of the width of the line. As far as human experience is concerned, the long-term evolution of the sun is so slow that it has made no difference at all on insolation for the entire time humans have existed. Insolation is also affected by cyclical changes in Earth’s orbit and rotation. Over intervals of approximately 100,000 years, the eccentricity of Earth’s orbit changes. Eccentricity is a measure of how elliptical a circle is. Higher eccentricity means that the orbit is more elliptical (Figure 16.5, left, blue orbit), whereas lower eccentricity means the orbit is more circular (Figure 16.5, left, red orbit). Eccentricity is important because when it is high, the Earth-sun distance varies more from season to season than it does when eccentricity is low. Over intervals of approximately 41,000 years, the obliquity of Earth’s axis of rotation changes (Figure 16.5, middle). This results in a nodding motion that alters how directly the sun shines on Earth’s poles. When the angle is at its maximum (24.5°), Earth’s seasonal differences are accentuated. When the angle is at its minimum (22.1°), seasonal differences are minimized. Cycles of precession happen over intervals of approximately 20,000 years, causing Earth’s axis of rotation to wobble (Figure 16.5, right). This means that although the North Pole is presently pointing to the star Polaris (the pole star), in 10,000 years it will point to the star Vega. The importance of eccentricity, tilt, and precession to Earth’s climate cycles (now known as Milanković Cycles) was first pointed out by Yugoslavian engineer and mathematician Milutin Milanković in the early 1900s. Milanković recognized that although the variations in the orbital cycles did not affect the total amount of insolation that Earth received, it did affect where on Earth that energy was strongest. Glaciations are most sensitive to the insolation received at latitudes of approximately 65°. As continents are configured today, this is most significant at 65° N, because there is almost no land at 65° S. The most important factors are whether the northern hemisphere is pointing toward or away from the sun at its closest or farthest approach, and how eccentric the sun’s position is in Earth’s orbit. For example, if the northern hemisphere is at it farthest distance from the sun during summer (Figure 16.6, top), this means cooler summers. If the northern hemisphere is at its closest distance to the sun during summer (Figure 16.6, bottom), this means hotter summers. Cool summers — as opposed to cold winters — are the key factor in the accumulation of glacial ice, so the upper scenario in Figure 16.6 is the one that promotes glaciation. This factor is greatest when eccentricity is high. The effects of all three cycles are evident in geochemical climate data. Figure 16.7 shows the “signals” for obliquity (A), eccentricity (B), and precession (C) over a period from 800,000 years in the past, to 800,000 years in the future. The vertical black line running down the middle of the diagram marks the present day. When the insolation from all three signals is determined, the result is a more complex waveform (D) with times of low variation in insolation, and times with higher variation in insolation. The graphs E and F are climate information measured in microfossils dwelling at the ocean floor (E) and in water from ice cores (F). Peaks in temperature in F correspond to peaks in the oxygen isotope record in E, which indicate that it was warmer, there was less ice, and sea level was higher. Troughs are times when Earth was deep within an ice age. It was cooler, there was ice on land, and sea level was lower. The vertical dashed lines on the left-hand side of Figure 16.7 mark the times of peak warm temperatures and allow for comparison of the timing of the temperature peaks with the timing of the orbital cycles. Peak temperature events are approximately 100,000 years apart, suggesting that the eccentricity cycle might be the most important contributor. Indeed, in B most (but not all) of the peak temperature events correspond to a time when Earth’s orbit was at or near peak eccentricity for that cycle. It is tempting to conclude that eccentricity is the most important orbital cycle for climate change over all. However, this pattern only began a little over 1 million years ago. For 1.5 million years before that, the 41,000-year obliquity cycle seems to dominate insolation cycles. In general, times of warmest or coolest temperatures don’t line up perfectly with orbital cycles. There is no one orbital cycle that is most important for all of Earth history. It is also the case that changes in insolation due to orbital cycles are not sufficient to cause temperatures to change as much as the geological record says they have; feedbacks must be factored in to explain the observed temperature changes. Sunspots are dark patches that appear on the surface of the sun as a result of intense local disturbances in the sun’s magnetic field (Figure 16.8, left). Loops of plasma (gas with electrical charge, Figure 16.8, right) follow along magnetic field lines from one sunspot to another. Sunspots appear dark because they are lower-temperature regions on the sun’s surface. For that reason you might think that more sunspots means a reduction in insolation. In fact, just the opposite is true, because sunspots are a side-effect of increased solar activity. Peaks in the number of sunspots counted annually since approximately 1870 (Figure 16.9, blue), coincide with peaks in measurements of solar energy output from the same time period (Figure 16.9, pink). Sunspot cycles happen over approximately 11 year intervals, and the changes in insolation that occur during these cycles are relatively small. In the end the effect of sunspot cycles on climate can be lost amidst other factors. In Figure 16.9 there is no clear relationship between the sunspot cycles and the global average temperatures (in grey) reported for the same period. Be Aware of Graph Scales Figure 16.9 shows three kinds of data: temperatures, sunspot numbers, and solar energy flow. Each of these data sets is a different type of information, so each needs its own vertical axis. The vertical axes are scaled so that the data fill the area of the graph as much as possible. Stretching the vertical scale to fit the full plotting area makes it easier to see how well the peaks and troughs in each record line up with each other. Unfortunately, this can also skew our impression of the data. For example, in the period from 1880 to 1920, all three records have a similar vertical distance from peak to trough. In other words, all three records have approximately the same size of wiggles. This does not mean that the change in insolation from sunspot cycles was big enough to cause all of the variation in the temperature record. From this graph alone, there is no way to tell how much the change in insolation due to sunspot cycles mattered to global temperatures during the period 1880 to 1920. Climate Forcing by Changes in Heat Transport The ocean transports large amounts of heat around the Earth through a conveyor-belt-like system of currents. The ocean has surface currents that are driven by wind, but it also has deeper currents that are not wind-driven. The deeper currents behave like stacked rivers because they are different temperatures and have different salt contents, and therefore different densities. The differences in density between these water masses are what drive circulation. Circulation that is driven by density is called thermohaline circulation; thermo refers to heat and haline refers to salt. To see how this works, consider the warm and saline Gulf Stream current (Figure 16.10, top). It flows northward past Britain and Iceland into the Norwegian Sea, and cools as it moves north, becoming denser. Its high salinity contributes to its density, and it sinks, or downwells, deep beneath the surrounding water, forming the North Atlantic Deep Water (NADW) current that flows south. Meanwhile, at the southern extreme of the Atlantic, very cold water adjacent to Antarctica also sinks to the bottom to become the Antarctic Bottom Water (AABW) current. The AABW flows north, beneath the NADW. The water that sinks in the areas of deep water formation in the Norwegian Sea and adjacent to Antarctica moves very slowly at depth. It eventually resurfaces, or upwells, in the Indian Ocean between Africa and India, and in the Pacific Ocean, north of the equator (Figure 16.11). Some ocean currents move warm water from the equator toward the poles. As in the example of the Drake Passage, the path of warm currents can have a significant impact on the climate of a region, and potentially of the planet as a whole. Processes that disrupt the density of seawater can slow or stop currents, preventing warm water from reaching higher latitudes. The recovery from the last ice age is characterized by sudden returns to glacial conditions over as little as 3 years. This is thought to be the result of enormous glacial lakes forming on continents as the glaciers melted, then being suddenly released into the ocean by a burst ice dam. The glacial water would be very cold, but it would also be fresh, making it less dense than the ocean water. The fresh glacial water would form a cap and slow the downwelling conveyor belt at high latitudes. Scientists are trying to determine the current and past state of the Atlantic-basin system of circulation, called the Atlantic Meridional Overturning Circulation (AMOC), to tell whether it is changing in response to warming and adding fresh water from melting ice sheets. The AMOC varies considerably on decadal cycles because of cycles in the wind patterns in the Atlantic, so it is important to distinguish these cyclical changes from any longer-term underlying changes. Because of these studies, we have an idea of what the physical properties of the Atlantic Ocean look like when circulation is stronger or weaker. When circulation slows, the density is lower in the downwelling regions (Figure 16.12, blue patch in the Labrador Sea). The density is higher south of this region, along the eastern coast of the United States and southern Canada (Figure 16.12, orange patch). Model simulations are used to confirm that the changes in density we observe are consistent with how we understand the circulation system to work. Measurements of the actual flow rate at depth in the Atlantic Ocean (Figure 16.12, right, blue dots) confirm that density decreases in downwelling regions (black and red lines) when circulation slows. A more recent study (Caesar et al., 2018) has shown that observed and model temperatures follow the same pattern, with cooling where the blue patches are in Figure 16.12, and warming in the region of the orange patches. This is to be expected because the slowdown in circulation affects how heat is moved northward. Is Atlantic Circulation Slowing Down More than Usual? Changes in the Atlantic meridional overturning circulation (AMOC) happen from decade to decade. To know whether circulation is changing compared to what is normal, it is necessary to get information about what circulation looked like in the past. This is difficult to do, because measurements of circulation rates, temperature, and salinity don’t go back as far as we need them to. In a new study, Thornalley et al. (2018) have used geochemical analyses of microfossils to build a longer-term record of temperatures, then used that record to look for the temperature “fingerprint” of slowing AMOC, an increasing difference in the temperatures of surface waters compared to deeper waters in the downwelling zone (Figure 16.13, top). They observe a longer-term cooling trend beginning at the close of the Little Ice Age, suggesting that less heat is being moved toward the downwelling zone (labelled A on the globe in Figure 16.13). They also measured the size of silt grains on the sea floor, above which a southward-moving component of the AMOC system flows (location labelled C on the globe in Figure 16.13). Grain size is used as a substitute for a direct measure of ocean current velocity because the velocity determines what grain size can be carried. They identified a lower average grain size over the past ~150 years compared to the average grain size from earlier (Figure 16.13, bottom, dashed lines). The authors of the study note that the average grain size changes more during cold events in the Northern Hemisphere (the Dark Ages Cold Period and the Little Ice Age). Thornalley et al (2018) conclude that the AMOC has been weaker on average during the past ~150 years than during the previous ~1,500 years. However, they cannot say for sure how much of that change is from melting that occurred at the close of the Little Ice Age, from melting triggered by warming since the Industrial Revolution, or some combination of the two. Direct measurements of density and current velocity tell us that as of 2017, the AMOC continues to weaken. Plate Tectonics and Heat Transport The opening of the Drake Passage is one example of how plate tectonic changes can affect ocean heat transport, and therefore climate. Plate tectonic changes that build or break up continents also play a role. When continents become large, ocean currents warm their margins, but the interiors can be much cooler. Anyone living on the Canadian prairies who has shivered through -40 °C temperatures in the winter, while watching news reports of rain in Vancouver will be familiar with this effect. When the supercontinent Gondwana was over the south pole approximately 300 million years ago (Figure 16.14), this triggered an ice age. The build-up of ice was hastened by the ice albedo feedback effect. Short-Term Cycles in Heat Transport: El Niño Southern Oscillation The El Niño Southern Oscillation (ENSO) operates on a much shorter timescale than climate forcings driven by plate tectonics or orbital cycles, alternating between El Niño and La Niña events on timescales of between two and seven years (Figure 16.15). Under normal conditions, strong winds blowing westward across the Pacific cause water to pile up in the western Pacific. This forces deeper colder water to the surface in the eastern Pacific (Figure 16.16, left). During La Niña events, further intensification of winds causes even more cold water to upwell. During an El Niño event, the winds weaken, allowing water to flow back to the east (Figure 16.16, right). The cold water settles deeper once again, meaning that warmer water is present along the eastern margin of the Pacific Ocean. ENSO events affect weather on a global scale (Figures 16.17 and 16.18). In western Canada, El Niño years have warmer than average winters, whereas La Niña years have cooler than average winters. Climate Forcing by Changes in the Atmosphere’s Energy Budget Earth’s atmosphere regulates climate by controlling how much energy from Earth’s surface escapes to space, and how much of the sun’s energy reaches Earth’s surface. Albedo is a measure of the reflectivity of a surface. Earth’s various surfaces have widely differing albedos, expressed as the percentage of light that reflects off a given material. This is important because most solar energy that hits a very reflective surface is not absorbed and therefore does little to warm Earth. Water in the oceans or on a lake is one of the darkest surfaces, reflecting less than 10% of the incident light. Clouds and snow or ice are among the brightest surfaces, reflecting 70% to 90% of the incident light (Figure 16.19). Albedo, Feedbacks, and the Acceptance of Milanković Cycles as a Climate Forcing Mechanism When Milanković published his hypothesis in 1924, it was widely ignored, partly because it was evident to climate scientists that the forcing produced by the orbital variations alone was not strong enough to drive the climate changes of the glacial cycles. Those scientists did not recognize the power of positive feedbacks. It wasn’t until 1973, 15 years after Milanković’s death, that sufficiently high-resolution data were available to show that the Pleistocene glaciations were indeed driven by the orbital cycles, and it became evident that the orbital cycles were just the first step, initiating a range of feedback mechanisms that made the climate change, many of which were related to albedo. Consider the following: - When large volumes of ice melt — such as the continental ice sheets of Antarctica and Greenland, as well as alpine glaciers— this decreases albedo. More solar energy is then absorbed by land, amplifying the increase in temperature. - When sea ice melts and exposes water, the albedo of the exposed area decreases drastically, from approximately 80% to less than 10%. Far more solar energy can be absorbed by the water compared to the previous ice cover, amplifying the temperature increase. - Sea level rises when ice and snow melt on land, and because seawater expands when heated. Higher sea level means a larger proportion of the planet is covered with water, which has a lower albedo than land. More heat is absorbed, amplifying the temperature increase. Since the last glaciation, a rise in sea level of approximately 125 m has flooded vast areas of land. Changes in climate can cause forests to be replaced by grasslands, which have higher albedo than dark forest cover. If deserts expand, vegetated areas can be replaced by higher-albedo sand. Many human activities affect albedo, including adding urban surfaces to an environment, and planting crops. Figure 16.20 shows a forest that has been clear-cut. If a clear-cut has an albedo similar to that of sand, how would clear cutting change the albedo of the area? Note that trees cool their environment through transpiration, when they release water vapour from their leaves. Changes in local temperatures when trees are clear-cut also include the effects of reduced evaporative cooling. Changes in vegetative cover also affect the rates of CO2 uptake by plants. Greenhouse Gases (GHGs) All molecules vibrate at various frequencies and in various ways, and some of those vibrations take place at frequencies within the range of the infrared radiation that is emitted by Earth’s surface. Gases with two atoms, such as O2, can only vibrate by stretching (back and forth; Figure 16.21 top), and those vibrations are much faster than that of IR radiation. Gases with three or more atoms (such as CO2) can vibrate in other ways, such as by bending (Figure 16.21 bottom). Those vibrations are slower and allow the molecules to absorb and release infrared radiation. When infrared radiation interacts with CO2 or with one of the other GHGs, the molecular vibrations are enhanced because there is a match between the wavelength of the light and the vibrational frequency of the molecule. This makes the molecule vibrate more vigorously, heating the surrounding air in the process. These molecules also emit infrared radiation in all directions, some of which reaches Earth’s surface. Heating due to the vibrations of greenhouse gas molecules is called the greenhouse effect. Water molecules (H2O), and methane molecules (CH4) also interact with infrared radiation when they vibrate, so they are greenhouse gases as well. Ice core records show that over the last 800,000 years, rapid cycles into and out of glacial temperatures are associated with similarly-timed cycles in atmospheric CO2 levels (Figure 16.21). Earth-System Response Time You might have noticed that for most of the 800,000-year record in Figure 16.22, there is a fairly consistent relationship between scale of change in atmospheric CO2 levels and the resulting change in temperature. You might also have noticed that compared to most of the record, the rise in temperature since 1950 is unexpectedly small, given the increase in atmospheric CO2 levels since that time. The reason for the relatively small temperature increase in response to the recent CO2 increase is in large part because the recent rise in CO2 is happening far more rapidly than other parts of the Earth system can respond. The ocean in particular is slowing down the response. The ocean takes up heat from the atmosphere, and thus helps to determine surface temperatures. A relatively cool ocean can take up more heat from the atmosphere, reducing warming. The fastest way for the ocean as a whole to take up heat is through the “stirring” that happens with ocean circulation, but circulation happens on thousand-year timescales. The slow rate of circulation means that centuries from now, there will still be cool water rising up from the deep ocean that has yet to be exposed to the warmer surface conditions. At other times in the 800,000-year record, changes in CO2 levels happened on timescales much closer to those at which the ocean takes up heat. Atmospheric Effects of Volcanic Eruptions Volcanic eruptions don’t just involve lava flows and exploding rock fragments. Eruptions also release particles and gases into the atmosphere. Important volcanic gases include water vapour, CO2, and sulphur dioxide (SO2). Volcanic CO2 emissions can contribute to climate warming if a greater-than-average level of volcanism is sustained over a long time. At the end of the Permian Period, the massive Siberian Traps were produced by eruptions lasting at least a million years. Large quantities of CO2 were released, warming the climate and triggering a cascade of Earth-system responses. The end of the Permian Period at 252 Ma is marked by the greatest mass extinction in Earth history. Over the shorter term, however, volcanic eruptions can have the opposite effect, cooling the climate. SO2 reacts with water in the atmosphere to make droplets of sulphuric acid. The sulphuric acid droplets scatter sunlight, reducing how much of the sun’s energy can reach Earth’s surface. They also affect cloud formation. The volcanic cooling effect is relatively short-lived, because the particles settle out of the atmosphere within a few years. Caesar, I., Rahmstorf, S., Robinson, A., Feulner, G., & Saba, V. (2018). Observed fingerprint of a weakening Atlantic Ocean overturning circulation. Nature 556. 194-196. https://doi.org/10.1038/s41586-018-0006-5 View abstract Ingleby, B., & Huddleston, M. (2007). Quality control of ocean temperature and salinity profiles—Historical and real-time data. Journal of Marine Systems, 65, 158-175. doi:10.1016/j.jmarsys.2005.11.019 Full text Jouzel, J., Masson-Delmotte, V., Cattani, O., Dreyfus, G., Falourd, S., Hoffmann, G., Minster, B., Nouet, J., Barnola, J.M., Chappellaz, J.A., Fischer, H., Gallet, J.C., Johnsen, S.J., Leuenberger, M., Loulergue, L., Luethi, D., Oerter, H., Parrenin, F., Raisbeck, G.M., Raynaud, D., Schilt, A., Schwander, J., Selmo, E., Souchez, R., Spahni, R., Stauffer, B., Steffensen, J.P., Stenni, B., Stocker, T.F., Tison, J.L., Werner, M., & Wolff, E.W. (2007). Orbital and Millennial Antarctic Climate Variability over the Past 800,000 Years. Science 317(5839), 793-797. Get data Lüthi, D., Le Floch, M., Bereiter, B.; Blunier, T., Barnola, J.M., Siegenthaler, U., Raynaud, D., Jouzel, J., Fischer, H., Kawamura, K., & Stocker, T.F. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature (453), 379-382. Get data RAPID-AMOC (n.d.) RAPID: monitoring the Atlantic Meridional Overturning Circulation at 26.5°N since 2004. Visit website (data available) Robson, J., Hodson, D., Hawkins, E., & Sutton, R. (2014). Atlantic overturning in decline? Nature Geoscience 7(2-3). https://doi.org/10.1038/ngeo2050 Open access version Shaffrey, L.C., Stevens, I., Norton, W. A., Roberts, M. J., Vidale, P. L., Harle, J. D., Jrrar, A., Stevens, D. P., Woodage, M. J., Demory, M. E., Donners, J., Clark, D. B., Clayton, A., Cole, J. W., Wilson, S. S., Connelley, W. M., Davies, T. M., Iwi, A. M., Johns, T. C., King, J. D., New, A. L., Singlo, J. M., Slingo, A., Steenman-Clark, L., & Martin, G. M. (2009). U.K. HiGEM: The New U.K. High-Resolution Global Environment Model—Model Description and Basic Evaluation. Journal of Climate 22, 1861 – 1896. doi:10.1175/2008JCLI2508.1 Full text Smith, D. M., & Murphy, J. M. (2007). An objective ocean temperature and salinity analysis using covariances from a global climate model. Journal of Geophysical Research, 112(C02022). doi:10.1029/2005JC003172 Thornalley, D. J. R., Oppo, D. W., Ortega, P., Robson, J. I., Brierley, C. M., Davis, R., Hall, I. R., Moffa-Sanchez, P., Rose, N. L., Spooner, P. T., Yashayaev, I., & Keigwin, L. D. (2018). Anomalously weak Labrador Sea convection and Atlantic overturning during the past 150 years. Nature 556, 227-230. https://doi.org/10.1038/s41586-018-0007-4 View abstract
The Science of Sticky Spheres On the strange attraction of spheres that like to stick together And Back to Geometry How were these geometric structures determined? The key idea is to transform the adjacency matrix A into a distance matrix D. Whereas each element Aij of the adjacency matrix is a binary value, answering the yes-or-no question “Do spheres i and j touch?,” the element Dij is a real number giving the Euclidean distance between i and j. As it happens, we already know some of those distances. Every 1 in the adjacency matrix designates a pair of unit spheres whose center-to-center distance is exactly 1; thus Aij=1 implies Dij=1. We even know something about the rest of the distances: A cluster is feasible only if every element of the distance matrix satisfies the constraint Dij≥1. Any distance smaller than 1 would mean that two spheres were occupying the same volume. To fully pin down the geometry of a cluster, we need to determine the x, y and z coordinates of all n spheres. A rule of elementary algebra suggests we would need 3n equations to determine these 3n unknowns, but in fact 3n–6 equations are enough. The energy of the cluster depends only on the relative positions of the n spheres, not on the absolute position or orientation of the cluster as a whole. In effect, the locations of two spheres come “for free.” We can arbitrarily assume that one sphere is at the origin of the coordinate system and another is exactly one unit away along the positive x axis. In this way six coordinates become fixed. Then the 3n–6 equations supplied by the 1s in the adjacency matrix are exactly the number needed to locate the rest of the spheres. Having just enough constraints to solve the system of equations is more than a convenient coincidence; it’s also a necessary condition for mechanical stability in a cluster. Specifically, having 3n–6 contacts and at least three contacts per sphere gives a cluster a property called minimal rigidity. If any sphere had only one or two contacts, it could flap or wobble freely. Such as cluster cannot be a max(Cn) configuration because the unconstrained sphere can always pivot to make contact with at least one more sphere, thereby increasing Cn. Each of the 3n–6 equations has the form: defining the distance between the centers of spheres i and j. To recover the coordinates of all the spheres, this system of equations must be solved. To that end, Arkus first tried a technique called a Gröbner basis, which in recent years has emerged as a powerful tool of algebraic geometry. The method offers a systematic way to reduce the number of variables until a solution emerges. An implementation of the Gröbner-basis algorithm built into a computer-algebra system was able to solve the n=7 equations, but it became too slow for n=8. Another approach relies on numerical methods that converge on a solution by successive approximation. The best-known example is Newton’s method of root-finding by refining an initial guess. Arkus found that the numerical techniques were successful and efficient, but she was concerned that they are not guaranteed to find all valid solutions. (Whenever the algorithm converges, the result is a correct solution, but failure to converge does not necessarily mean that no solution exists; it’s also possible that the initial guess was in the wrong neighborhood.) Setting aside the algebraic and numerical techniques, Arkus chose to rely on geometric reasoning both as a guide to assembling feasible clusters and as a means of excluding unphysical ones. A basic rule for unit spheres states that if i touches j, then j’s center must lie somewhere on a sphere of radius 1 centered on i—the “neighbor sphere.” If k touches both i and j, then k’s center must be somewhere on the circular intersection of two neighbor spheres. If l touches all three of i, j and k, the possible locations are confined to a set of two points. With a handful of rules of this general kind, it’s always possible to solve for the unknown distances in a distance matrix—assuming that the adjacency matrix describes a feasible structure. Other geometric rules can be applied to prove that certain classes of adjacency matrices cannot possibly yield a physical sphere packing. For example, if spheres i, j and k all touch one another, they must form an equilateral triangle. If the pattern of 1s in the adjacency matrix shows that more than two other spheres also touch i, j and k, then the cluster cannot exist in three-dimensional space. The unphysical matrices can be eliminated without even exploring the geometry of the clusters. Arkus also made use of the Geomags construction set to check the feasibility of certain sphere arrangements. The Geomags set consists of polished steel balls and bar-magnet struts encased in colored plastic; all the struts are the same length, and so they can readily be assembled into a skeleton of unit-length bonds between sphere centers. Having a three-dimensional model you can hold in your hand is a great aid to geometric intuition.
Mathematics & Science Numerical Methods for Solving Differential Equations (continued from last page...) Developing Euler's Method Graphically In order to develop a technique for solving first order initial value problems numerically, we should first agree upon some notation. We will assume that the problem in question can be algebraically manipulated into the form: y′ = f(x, y) Our goal is to find a numerical solution, i.e. we must find a set of points which lie along the initial value problem's solution. If we look at this problem, as stated above, we should realize that we actually already know one point on the solution, namely the one defined by the initial condition, (xo, yo). Possibly, the picture of this tiny piece of information looks something like this: Now, remember we don't really know the true solution of the problem, or we wouldn't be going through this method at all. But let's act as if we do know this elusive solution for a moment. Let's pretend that it's "ghostly graph" could be superimposed onto our previous picture to get this: Again, the blue graph of the true solution, shown above, is actually unknown. We've drawn a picture of what it might look like just to help us think. Since we're after a set of points which lie along the true solution, as stated above, we must now derive a way of generating more solution points in addition to the solitary initial condition point shown in red in the picture. How could we get more points? Well, look back at the original initial value problem at the top of the page! So far we have only used the initial condition, which gave us our single point. Maybe we should consider the possibility of utilizing the other part of the initial value problem—the differential equation itself: y′ = f(x, y) Remember that one interpretation of the quantity y′ appearing in this expression is as the slope of the tangent line to the function y. But, the function y is exactly what we are seeking as a solution to the problem. This means that we not only know a point which lies on our elusive solution, but we also know a formula for its slope: slope of the solution = f(x, y) All we have to do now is think of a way of using this slope to get those "other points" that we've been after! Well, look at the right hand side of the last formula. It looks like you can get the slope by substituting values for x and y into the function f. These values should, of course, be the coordinates of a point lying on the solution's graph—they can't just be the coordinates of any point anywhere in the plane. Do we know of any such points—points lying on the solution curve? Of course we do! The initial condition point that we already sketched is exactly such a point! We could use it to find the slope of the solution at the initial condition. We would get: slope of the solution at (xo, yo) = f(xo, yo) Remembering that this gives us the slope of the function's tangent line at the initial point we could put this together with the initial point itself to build the tangent line at the initial point, like this: Once again, let's remind ourselves of our goal of finding more points which lie on the true solution's curve. Using what we know about the initial condition, we've built a tangent line at the initial condition's point. Look again at the picture of this line in comparison with the graph of the true solution in the picture above. If we're wanting other points along the path of the true solution, and yet we don't actually have the true solution, then it looks like using the tangent line as an approximation might be our best bet! After all, at least on this picture, it looks like the line stays pretty close to the curve if you don't move too far away from the initial point. Let's say we move a short distance away, to a new x-coordinate of x1. Then we could locate the corresponding point lying on our tangent line. (We can't do this for the curve—it's a ghost, remember!) It might look something like this: Notice that our new point, which I've called (x1, y1), isn't too terribly far away from the true value of the solution at this x-coordinate, up on the curve. So we now have two points as part of our numerical solution: We must now attempt to continue our quest for points on the solution curve (though we're starting to see the word "on" as a little optimistic—perhaps "near" would be a more realistic word here.) Still glowing from our former success, we'll dive right in and repeat our last trick, constructing a tangent line at our new point, like this: You should immediately recognize that there's a problem, and I've cheated to overcome it! Since our new point didn't actually lie on the true solution, we can't actually produce a tangent line to the solution at this point. (We don't even know where the true solution actually is anymore—the blue curve in the picture is just a thinking aid.) But we can still substitute our new point, (x1,y1), into the formula: slope of the solution = f(x,y) to get get the slope of a pseudo-tangent line to the curve at (x1,y1). We hope that our approximate point, (x1,y1), is close enough to the real solution that the pseudo-tangent line is pretty close to the unknown real tangent line. We now attempt to use this new pseudo-tangent line to get yet another point in the approximate solution. As before, we move a short distance away from our last point, to a new x-coordinate of x2. Then we locate the corresponding point lying on our pseudo-tangent line. The result might look something like this: We now have three points in our approximate solution: As you can see, we're beginning to establish a pattern in the way we are generating new points. We could continue making new points like this for as long as we liked, but for the sake of this illustration let's find just one more value in the approximate solution. We make another pseudo-tangent line, this time through (x2, y2), like this: and we make another short jump to an x-coordinate of x3, and locate the corresponding point on our latest pseudo-tangent line, like this: So the list of points in our approximate numerical solution now has four members: Looking over the picture one last time, we see an example of how the numerical solution—the red dots, might compare with the actual solution. As we stated in the introduction to this laboratory, a weakness of numerical solutions is their tendency to drift away from the true solution as the points get further away from the initial condition point. One way of minimizing (but not eliminating) this problem is to make sure that the jump-size between consecutive points is relatively small. Now that you've seen the pictorial version of Euler's Method for finding numerical solutions, you should have a better chance of understanding the derivation of the formulas used by the method. So, let's go and derive them... ODE Laboratories: A Sabbatical Project by Christopher A. Barker ©2017 San Joaquin Delta College, 5151 Pacific Ave., Stockton, CA 95207, USA
TUCSON — From the early 1700s until the 1960s, the fast moving river of wind known as the North Atlantic Jet Stream, which drives weather extremes over Europe, was pretty steady on its course. Then it became less predictable. But instrument data alone can’t tell the jet stream’s movements for comparison over the centuries, given that scientists began keeping records of weather events via instruments only in the late 19th century. The rings of trees, however, offer a far more complete historical picture of climate variations. As they age, trees form new distinctive rings, outward from the center, and each year a new, distinct circle of dead wood is created around the trunk of most trees. In that ring, one can find information about precipitation, temperature and other data about that year. A team led by Valerie Trouet, a dendrochronologist, sampled 400 trees from the Balkans and 200 in Scotland — including what might be the oldest known tree in Europe, a Bosnian pine in Greece named Adonis, which is 1,075 years old. The jet stream flows between these two regions, and trees revealed the range of temperatures in their rings and the frequency of fires over time, an expansive chronicling of jet stream behavior. “More extreme positions create more extreme climate events, especially heat waves and storms,” in Europe, Dr. Trouet said. And the tree rings show “big fires happen in the Balkans when the jet is in its southerly position.” The fact that the stream has become more variable only in recent decades suggests that the shift is the result of humans’ effects on climate, Dr. Trouet said. “The recent rise in variance is unprecedented in 300 years,” she said. More analysis is underway to look back to even earlier centuries. Reading the climate stories these trees tell will help with forecasting. “One of the big questions in the field is what’s going to happen to the jet stream,” said Dr. Trouet. “This data helps the modeling of climate change become more reliable.” Trees, it seems, are giant organic recording devices that contain information about past climate, civilizations, ecosystems and even galactic events, much of it many thousands of years old. In recent years, the techniques for extracting information from tree rings has been honed and expanded. New technologies and techniques are able to pry a much deeper and wider range of information out of trees. The field “has exploded,” Edward Cook, director of the tree ring lab at Lamont-Doherty Earth Observatory, said. The Laboratory of Tree-Ring Research here at the University of Arizona was founded in the 1930s by A.E. Douglass, an astronomer who turned to trees to better understand the connection between sunspots and climate. The lab has helped establish other labs around the world, which in turn has rapidly increased the number of studied trees. There are now roughly a dozen large labs globally and data from 4,000 sites on all continents except Antarctica. The information is stored in the International Tree Ring Data Bank, a library open to all researchers. As more tree data becomes available, a much richer picture forms of the nexus of past climate, ecosystems and human civilization. For its first 80 years, the lab was located in much smaller — and noisier — quarters under the University of Arizona football stadium. “If you worked on Saturdays you could hear people in the bleachers stamping their feet,” said Russell K. Monson, who studies plant physiology here. In 2012, the lab moved into a larger building to accommodate its growing mission and number of researchers — now some 70 or so — and to unpack its vast collection of tree rings and core samples. There are now more than a half-million samples, from slivers to an enormous slice of giant sequoia in the lobby, a large enough table top, perhaps, to seat all of King Arthur’s knights. The building houses the world’s largest collection of tree ring samples. The basement storage area resembles a coffee table wood shop, infused with the fragrant perfume of cut wood. Hundreds of two-inch-thick slices of large trees, their rich grains sanded and polished, are stacked on their sides. The lab also houses a slice of the bristlecone pine that was cut down in the 1960s by a graduate student named Donald Rusk Currey from the University of North Carolina at Chapel Hill. It wasn’t until after he felled the tree and counted the rings that he realized, to his horror, that he had, with permission from the United States Forest Service, unceremoniously sawed down the oldest known tree in the world — a stately gnarled pine called Prometheus. Research involving tree rings is divided into three main categories — dendroclimatology, the analysis of tree rings for past climate data; dendroarchaeology, the study of tree rings to understand how past climate affected human societies; and dendroecology, which reconstructs past forest ecosystems. The most common tree rings studied come from bristlecone pine, fir and spruce. At this particular time, the most essential role for tree rings is probably their use in reconstructing past climate and providing much greater context. “The instrumental period provides a snapshot,” of past climate, said David Meko, a researcher here, “but the tree rings are a panorama.” This window into the deep climate past has become vital in a rapidly warming world, to show how the climate of the last half-century is far outside the historical norms going back thousands of years. Living bristlecone pine trees, for example, are several thousand years old and their information is added to by those that died thousands of years ago, but remained intact in their cold, dry high-altitude environment. [Like the Science Times page on Facebook. \| Sign up for the Science Times newsletter.] It’s hard to argue with tree rings that huge environmental changes are not occurring. Climate change seen in the past six or seven decades has few, if any, comparisons in the far past, researchers say. The current two-decade-long drought on the Colorado River, for instance, is the longest since medieval times when a drought lasted for 62 years — with no very wet years in between dry years. An occasional very wet year can make a long drought more bearable. Moreover, conditions in some recent years are the hottest and driest in many centuries. “We keep breaking records year after year,” Dr. Meko said. “It’s a little worrisome to see the most extreme years right near the present.” Unprecedented hot droughts, like the current one, make a decline in precipitation even worse, by causing more evaporation. Officials along the Colorado River are deeply worried about the trend toward warmer temperatures and less precipitation and are preparing for a grim future without or with less river water — unthinkable just 20 years ago. (This year though, was an El Niño year, and the snowpack in the Colorado Rockies was well above average.) To make matters worse, tree rings show that water in the Colorado River was apportioned to states based on flow from 1905 to 1922, some of the wettest years in the last 12 centuries, an era known as a pluvial period. Researchers can also look at snowpack in tree ring records. In 2015, in the Sierras the snowpack was the lowest in 500 years. This year may be one of the highest snowpacks in decades, a testament perhaps to climate whiplash. Researchers here are reconstructing snowpack data by examining tree ring records across the entire western United States for the last 2,000 years. Trees hold other valuable information as well. Oxygen isotope analysis, for example, has unlocked the source of the water that a tree took up centuries ago and can determine whether it was from a hurricane or a severe thunderstorm. Tree rings also provide a glimpse into the possible global impacts of geoengineering — a proposal to scatter aluminum sulfate into the atmosphere to block the sun and cool the planet, which some scientists have proposed as a solution to climate change. “Volcanic eruptions are the best proxy of geoengineering,” Dr. Trouet said. Rings analyzed from trees in five locations around the world show that after a volcano erupted in 1568, the global climate cooled considerably for two years — evidenced in narrow tree rings — and the northern edge of the tropics receded as the planet cooled. Those tree rings also showed that during six decades, from 1568 until 1634, there was, because of natural climate variation, six decades of expansion of the subtropics, which pushed desert climates north. Because of expanding zones of hot and dry weather, the Ottoman Empire began to decline, the Ming dynasty collapsed and the Jamestown colony in Virginia was abandoned, suggesting, Dr. Trouet said, they were in part at least, climate-related. “The way society handles a drought politically is also part of the picture,” she said. Other sources — lake sediments; ice core samples; coral; the otolith, or ear bone, of fish; and even the shells from living and long dead geoducks, a large bivalve with a snakelike appendage — add to the broader picture. “We have divers sucking up ancient geoducks off the ocean floor,” said Bryan Black, a professor of dendrochronology who also specializes in marine organisms. Combined with long dead geoduck shells, data could go back many thousands of years. Shells from the coast of Iceland already go back 1,000 years. “They show that the last century is unprecedentedly warm,” Dr. Black said. Experts are using the shell ring information, combined with tree ring data, to understand how climate drives ocean productivity and the species mix of fish, to assist fisheries managers. “The bottom line is to be aware of climate whiplash and what that means for fisheries,” Dr. Black said. Even the stars give up some of their secrets to trees. The sun and other stars emit radiation called Galactic Cosmic Rays, or G.C.R.s, that react in the atmosphere with nitrogen and change the levels of carbon 14, which is taken up by every living thing and becomes a tracer for cosmic ray levels. Past spikes in G.C.R.s from solar flares or other sources are largely a mystery, but have attracted keen interest from researchers, because if they occur now they could wipe out communication satellites and other technology. An event in 774-775, first found in Japanese cedar trees and since found globally, is the strongest cosmic ray event in the tree ring record, a magnitude larger than the Carrington event, a solar storm in 1859, and apparently noted by people alive at the time. “This year also appeared in the heavens a red crucifix, after sunset,” was how the Anglo-Saxon Chronicles reported the event in the mid-eighth century. It was most likely a huge solar flare. “It is unprecedented, there’s nothing else like it,” said Charlotte Pearson, a professor at the tree ring lab. “We’re trying to work out what it is and what caused it but we’re still not sure.”B: 七仙女心水论坛76722免费资料【陈】【美】【雪】【摇】【头】【起】【来】，【秦】【明】【文】【看】【来】【这】【一】【次】【是】【买】【到】【假】【货】【了】，【有】【这】【么】【多】【不】【一】【样】【的】【地】【方】，【应】【该】【不】【是】【正】【品】。 “【看】【来】【你】【也】【有】【失】【手】【的】【时】【候】【啊】，【我】【还】【以】【为】【你】【什】【么】【都】【能】【够】【鉴】【定】【真】【假】，【你】【在】【佛】【山】【有】【这】【么】【多】【的】【问】【题】，30【万】【看】【来】【买】【亏】【了】【呀】。” “【这】【个】【佛】【像】【有】【点】【与】【众】【不】【同】【啊】。” 【听】【到】【这】【话】【他】【以】【为】【是】【假】【的】【了】，【秦】【明】【文】【皱】【眉】【头】【起】【来】，【难】【道】【他】【也】【时】【隔】【十】【年】，【三】【姐】【妹】【终】【次】【相】【聚】！ “【学】【校】【破】【旧】【好】【多】【啊】！” 【小】【花】【手】【指】【划】【过】【楼】【梯】【扶】【手】【的】【划】【痕】，【笑】【着】【说】，“【你】【们】【看】，【我】【就】【说】【划】【在】【反】【面】，【不】【会】【被】【人】【发】【现】【吧】！” “【那】【说】【明】，【没】【有】【人】【想】【到】【破】【坏】【公】【物】【啊】！”【大】【侠】【撇】【撇】【嘴】，【幼】【稚】！【陈】【悦】【笑】【眯】【眯】【的】【也】【来】【用】【手】【摸】【扶】【手】【的】【刻】【痕】。【当】【时】【是】【她】【和】【小】【花】【拿】【着】【圆】【规】，【用】【尖】【尖】【的】【那】【一】【头】 “【这】【次】【的】【行】【动】【不】【需】【要】【大】【张】【旗】【鼓】，【速】【战】【速】【决】。”【月】【华】【穿】【着】【一】【袭】【黑】【色】【的】【西】【服】，【内】【衬】【黑】【色】【衬】【衣】，【领】【带】【系】【的】【工】【工】【整】【整】，【一】【头】【长】【发】【披】【散】【着】，【撑】【着】【一】【柄】【古】【朴】【的】【白】【伞】，【站】【在】【阳】【的】【机】【甲】【肩】【膀】【上】，【这】【种】【装】【扮】【在】【她】【身】【上】【并】【没】【有】【什】【么】【违】【和】。【清】【冷】【的】【声】【线】【传】【进】【了】【每】【个】【人】【的】【耳】【朵】【里】，【印】【着】【月】【环】【星】【标】【志】【的】【机】【甲】【队】【动】【作】【整】【齐】【划】【一】【的】【启】【动】【了】【引】【擎】。【在】【话】【音】【刚】【落】，【就】【走】【进】【来】【两】【位】【雍】【容】【华】【贵】【的】【妇】【人】。 “【小】【寒】！【小】【枝】！” “【小】【枝】！【小】【寒】！” 【冷】【寒】【冬】【与】【元】【小】【枝】【对】【视】【一】【眼】，【同】【时】【看】【了】【眼】【气】【定】【神】【闲】【喝】【着】【茶】【的】【冷】【君】，【同】【时】【在】【心】【里】【暗】【叹】，【果】【然】，【姜】【还】【是】【老】【的】【辣】。 “【母】【后】，【干】【娘】。”【冷】【寒】【冬】【对】【着】【自】【己】【的】【母】【后】【和】【元】【小】【枝】【的】【娘】【亲】【行】【礼】【道】。 “【娘】【亲】，【干】【娘】。”【元】【小】【枝】【则】【是】【对】【着】【自】【己】七仙女心水论坛76722免费资料【一】【个】【小】【时】【之】【后】，【在】【白】【象】【街】【后】【面】【的】【一】【处】【废】【弃】【仓】【库】【里】，【久】【保】【由】【美】【女】【扮】【男】【装】，【头】【戴】【礼】【帽】，【身】【着】【风】【衣】，【将】【自】【己】【半】【张】【脸】【藏】【在】【了】【风】【衣】【衣】【领】【下】，【站】【在】【角】【落】【里】，【注】【视】【着】【仓】【库】【大】【门】【外】【的】【动】【静】。【过】【了】【没】【多】【久】，【孙】【建】【良】【推】【着】【一】【辆】【粪】【车】，【车】【上】【放】【着】【一】【把】【粪】【勺】，【吱】【吱】【纽】【纽】【地】【把】【粪】【车】【推】【进】【了】【这】【个】【废】【弃】【的】【仓】【库】【里】。 “【有】【人】【吗】？”【孙】【建】【良】【放】【下】【粪】【车】， “【老】【婆】，【我】【回】【来】【了】。”【王】【子】【程】【刚】【下】【班】【一】【进】【门】【就】【首】【先】【同】【坐】【在】【沙】【发】【上】【的】【郗】【颖】【报】【道】。 “【回】【来】【啦】。”【郗】【颖】【从】【笔】【记】【本】【电】【脑】【前】【抬】【起】【头】【冲】【王】【子】【程】【甜】【甜】【一】【笑】，【接】【着】【埋】【头】【看】【自】【己】【的】【电】【脑】。 “【又】【在】【追】【剧】？”【王】【子】【程】【凑】【过】【脸】【来】【揽】【住】【郗】【颖】【道】。 “【没】，【在】【码】【字】。”【郗】【颖】【边】【敲】【打】【键】【盘】【边】【无】【不】【惋】【惜】【的】【说】【道】，“【一】【起】【同】【过】【窗】【两】【部】【我】【都】【追】【完】【了】，【还】【这】【两】【天】【在】【忙】【毕】【业】【论】【文】【的】【开】【题】，【扒】【光】【头】【发】【的】【那】【种】【忙】，【满】【脑】【子】【都】【是】【光】【子】【晶】【体】，【恨】【不】【得】【让】【江】【枫】【现】【在】【就】【回】【去】【写】【毕】【业】【论】【文】。【原】【本】【上】【个】【学】【期】【就】【找】【好】【的】【毕】【业】【论】【文】【指】【导】【老】【师】，【因】【为】【我】【起】【晚】【了】【没】【了】。（【睡】【懒】【觉】【的】【下】【场】！！！）【现】【在】【我】【要】【开】【始】【在】【图】【书】【馆】【大】【海】【捞】【针】【寻】【找】【一】【个】【虽】【然】【没】【学】【过】【但】【看】【起】【来】【能】【写】【的】【毕】【业】【论】【文】【的】【题】【目】。【更】【新】【明】【日】【补】 117【合】【谋】【害】【萧】【适】【意】【周】【仲】【虽】【说】【混】【上】【昆】【仑】【的】【掌】【门】【是】【他】【运】【气】【好】，【但】【是】【他】【本】【身】【也】【是】【有】【点】【脑】【子】【的】，【一】【听】【说】【完】【就】【直】【指】【漏】【洞】【所】【在】 “【你】【说】【那】【个】【女】【人】【说】【萧】【上】【仙】【是】【萧】【煜】？【有】【何】【证】【明】【她】【可】【有】【告】【诉】【你】，【别】【被】【她】【利】【用】【了】。” **【听】【他】【这】【样】【一】【说】【也】【起】【了】【怀】【疑】，【那】【个】【云】【蔓】【从】【头】【到】【尾】【都】【没】【证】【明】【萧】【适】【意】【是】【萧】【煜】，【难】【道】【就】【因】【为】【他】【们】【都】【姓】【萧】？
\|Act of Parliament\| \|Long title\|\|An Act for a Union of the Two Kingdoms of England and Scotland\| \|Citation\|\|1706 c. 11\| \|Territorial extent\|\|Kingdom of England (inc. Wales); subsequently, Kingdom of Great Britain and United Kingdom\| \|Commencement\|\|1 May 1707\| Status: Current legislation \|Revised text of statute as amended\| \|Act of Parliament\| \|Long title\|\|Act Ratifying and Approving the Treaty of Union of the Two Kingdoms of Scotland and England\| \|Citation\|\|1707 c. 7\| \|Territorial extent\|\|Kingdom of Scotland; subsequently, Kingdom of Great Britain and United Kingdom\| \|Commencement\|\|1 May 1707\| Status: Current legislation \|Revised text of statute as amended\| \|Constitutional documents and events relevant to the status of the United Kingdom and its countries\| The Acts of Union (Scottish Gaelic: Achd an Aonaidh) were two Acts of Parliament: the Union with Scotland Act 1706 passed by the Parliament of England, and the Union with England Act 1707 passed by the Parliament of Scotland. They put into effect the terms of the Treaty of Union that had been agreed on 22 July 1706, following negotiation between commissioners representing the parliaments of the two countries. By the two Acts, the Kingdom of England and the Kingdom of Scotland—which at the time were separate states with separate legislatures, but with the same monarch—were, in the words of the Treaty, "United into One Kingdom by the Name of Great Britain". The two countries had shared a monarch since the Union of the Crowns in 1603, when King James VI of Scotland inherited the English throne from his double first cousin twice removed, Queen Elizabeth I. Although described as a Union of Crowns, and in spite of James's acknowledgement of his accession to a single Crown, England and Scotland were officially separate Kingdoms until 1707 (as opposed to the implied creation of a single unified Kingdom, exemplified by the later Kingdom of Great Britain). Prior to the Acts of Union there had been three previous attempts (in 1606, 1667, and 1689) to unite the two countries by Acts of Parliament, but it was not until the early 18th century that both political establishments came to support the idea, albeit for different reasons. The Acts took effect on 1 May 1707. On this date, the Scottish Parliament and the English Parliament united to form the Parliament of Great Britain, based in the Palace of Westminster in London, the previous home of the English Parliament. This specific process is sometimes referred to as the "union of the Parliaments" in Scotland. Political background prior to 1707 Prior to 1603, England and Scotland had different monarchs; as Elizabeth I never married, after 1567, her heir-presumptive became the Stuart king of Scotland, James VI, who was brought up as a Protestant. After her death, the two Crowns were held in personal union by James, as James I of England, and James VI of Scotland. He announced his intention to unite the two, using the royal prerogative to take the title "King of Great Britain", and give a British character to his court and person. The 1603 Union of England and Scotland Act established a joint Commission to agree terms, but the English Parliament was concerned this would lead to the imposition of an absolutist structure similar to that of Scotland. James was forced to withdraw his proposals, and attempts to revive it in 1610 were met with hostility. Instead, he set about creating a unified Church of Scotland and England, as the first step towards a centralised, Unionist state. However, despite both being nominally Episcopal in structure, the two were very different in doctrine; the Church of Scotland, or kirk, was Calvinist in doctrine, and viewed many Church of England practices as little better than Catholicism. As a result, attempts to impose religious policy by James and his son Charles I ultimately led to the 1639–1651 Wars of the Three Kingdoms. The 1639–1640 Bishops' Wars confirmed the primacy of the kirk, and established a Covenanter government in Scotland. The Scots remained neutral when the First English Civil War began in 1642, before becoming concerned at the impact on Scotland of a Royalist victory. Presbyterian leaders like Argyll viewed union as a way to ensure free trade between England and Scotland, and preserve a Presbyterian kirk. Under the 1643 Solemn League and Covenant, the Covenanters agreed to provide military support for the English Parliament, in return for religious union. Although the treaty referred repeatedly to 'union' between England, Scotland, and Ireland, political union had little support outside the Kirk Party. Even religious union was opposed by the Episcopalian majority in the Church of England, and Independents like Oliver Cromwell, who dominated the New Model Army. The Scots and English Presbyterians were political conservatives, who increasingly viewed the Independents, and associated radical groups like the Levellers, as a bigger threat than the Royalists. Both Royalists and Presbyterians agreed monarchy was divinely ordered, but disagreed on the nature and extent of Royal authority over the church. When Charles I surrendered in 1646, they allied with their former enemies to restore him to the English throne. After defeat in the 1647–1648 Second English Civil War, Scotland was occupied by English troops which were withdrawn once the so-called Engagers whom Cromwell held responsible for the war had been replaced by the Kirk Party. In December 1648, Pride's Purge confirmed Cromwell's political control in England by removing Presbyterian MPs from Parliament, and executing Charles in January 1649. Seeing this as sacrilege, the Kirk Party proclaimed Charles II King of Scotland and Great Britain, and agreed to restore him to the English throne. Defeat in the 1649–1651 Third English Civil War or Anglo-Scottish War resulted in Scotland's incorporation into the Commonwealth of England, Scotland and Ireland, largely driven by Cromwell's determination to break the power of the kirk, which he held responsible for the Anglo-Scottish War. The 1652 Tender of Union was followed on 12 April 1654 by An Ordinance by the Protector for the Union of England and Scotland, creating the Commonwealth of England, Scotland and Ireland. It was ratified by the Second Protectorate Parliament on 26 June 1657, creating a single Parliament in Westminster, with 30 representatives each from Scotland and Ireland added to the existing English members. While integration into the Commonwealth established free trade between Scotland and England, the economic benefits were diminished by the costs of military occupation. Both Scotland and England associated union with heavy taxes and military rule; it had little popular support in either country, and was dissolved after the Restoration of Charles II in 1660. The Scottish economy was badly damaged by the English Navigation Acts of 1660 and 1663 and England's wars with the Dutch Republic, Scotland's major export market. An Anglo-Scots Trade Commission was set up in January 1668 but the English had no interest in making concessions, as the Scots had little to offer in return. In 1669, Charles II revived talks on political union; his motives were to weaken Scotland's commercial and political links with the Dutch, still seen as an enemy and complete the work of his grandfather James I. Continued opposition meant these negotiations were abandoned by the end of 1669. Following the Glorious Revolution of 1688, a Scottish Convention met in Edinburgh in April 1689 to agree a new constitutional settlement; during which the Scottish Bishops backed a proposed union in an attempt to preserve Episcopalian control of the kirk. William and Mary were supportive of the idea but it was opposed both by the Presbyterian majority in Scotland and the English Parliament. Episcopacy in Scotland was abolished in 1690, alienating a significant part of the political class; it was this element that later formed the bedrock of opposition to Union. The 1690s were a time of economic hardship in Europe as a whole and Scotland in particular, a period now known as the Seven ill years which led to strained relations with England. In 1698, the Company of Scotland Trading to Africa and the Indies received a charter to raise capital through public subscription. The Company invested in the Darién scheme, an ambitious plan funded almost entirely by Scottish investors to build a colony on the Isthmus of Panama for trade with East Asia. The scheme was a disaster; the losses of over £150,000[a] severely impacted the Scottish commercial system. The Acts of Union may be seen within a wider European context of increasing state centralisation during the late 17th and early 18th centuries, including the monarchies of France, Sweden, Denmark and Spain. While there were exceptions, such as the Dutch Republic or the Republic of Venice, the trend was clear. The dangers of the monarch using one Parliament against the other first became apparent in 1647 and 1651. It resurfaced during the 1679 to 1681 Exclusion Crisis, caused by English resistance to the Catholic James II (of England, VII of Scotland) succeeding his brother Charles. James was sent to Edinburgh in 1681 as Lord High Commissioner; in August, the Scottish Parliament passed the Succession Act, confirming the divine right of kings, the rights of the natural heir "regardless of religion", the duty of all to swear allegiance to that king, and the independence of the Scottish Crown. It then went beyond ensuring James's succession to the Scottish throne by explicitly stating the aim was to make his exclusion from the English throne impossible without "the fatall and dreadfull consequences of a civil war". The issue reappeared during the 1688 Glorious Revolution. The English Parliament generally supported replacing James with his Protestant daughter Mary, but resisted making her Dutch husband William of Orange joint ruler. They gave way only when he threatened to return to the Netherlands, and Mary refused to rule without him. In Scotland, conflict over control of the kirk between Presbyterians and Episcopalians and William's position as a fellow Calvinist put him in a much stronger position. He originally insisted on retaining Episcopacy, and the Committee of the Articles, an unelected body that controlled what legislation Parliament could debate. Both would have given the Crown far greater control than in England but he withdrew his demands due to the 1689–1692 Jacobite Rising. The English succession was provided for by the English Act of Settlement 1701, which ensured that the monarch of England would be a Protestant member of the House of Hanover. Until the Union of Parliaments, the Scottish throne might be inherited by a different successor after Queen Anne, who had said in her first speech to the English parliament that a Union was "very necessary". The Scottish Act of Security 1704, however, was passed after the English parliament, without consultation with Scotland, had designated Electoress Sophia of Hanover (granddaughter of James I and VI) as Anne's successor, if Anne died childless. The Act of Security granted the Parliament of Scotland, the three Estates, the right to choose a successor and explicitly required a choice different from the English monarch unless the English were to grant free trade and navigation. Next the Alien Act 1705 was passed in the English parliament designating Scots in England as "foreign nationals" and blocking about half of all Scottish trade by boycotting exports to England or its colonies, unless Scotland came back to negotiate a Union. To encourage a Union, "honours, appointments, pensions and even arrears of pay and other expenses were distributed to clinch support from Scottish peers and MPs". The Scottish economy was severely impacted by privateers during the 1688–1697 Nine Years' War and the 1701 War of the Spanish Succession, with the Royal Navy focusing on protecting English ships. This compounded the economic pressure caused by the Darien scheme, and the seven ill years of the 1690s, when 5–15% of the population died of starvation. The Scottish Parliament was promised financial assistance, protection for its maritime trade, and an end to economic restrictions on trade with England. The votes of the Court party, influenced by Queen Anne's favourite, the Duke of Queensberry, combined with the majority of the Squadrone Volante, were sufficient to ensure passage of the treaty. Article 15 granted £398,085 and ten shillings sterling to Scotland,[b] a sum known as The Equivalent, to offset future liability towards the English national debt, which at the time was £18 million,[c] but as Scotland had no national debt, most of the sum was used to compensate the investors in the Darien scheme, with 58.6% of the fund allocated to its shareholders and creditors. The role played by bribery has long been debated; £20,000 was distributed by the Earl of Glasgow,[d] of which 60% went to James Douglas, 2nd Duke of Queensberry, the Queen's Commissioner in Parliament. Another negotiator, Argyll was given an English peerage. Robert Burns is commonly quoted in support of the argument of corruption: "We're bought and sold for English Gold, Such a Parcel of Rogues in a Nation." As historian Christopher Whatley points out, this was actually a 17th-century Scots folk song; but he agrees money was paid, though suggests the economic benefits were supported by most Scots MPs, with the promises made for benefits to peers and MPs, even if it was reluctantly. Professor Sir Tom Devine agreed that promises of "favours, sinecures, pensions, offices and straightforward cash bribes became indispensable to secure government majorities". As for representation going forwards, Scotland was, in the new united parliament, only to get 45 MPs, one more than Cornwall, and only 16 (unelected) peers in the House of Lords. Sir George Lockhart of Carnwath, the only Scottish negotiator to oppose Union, noted "the whole nation appears against (it)". Another negotiator, Sir John Clerk of Penicuik, who was an ardent Unionist, observed it was "contrary to the inclinations of at least three-fourths of the Kingdom". As the seat of the Scottish Parliament, demonstrators in Edinburgh feared the impact of its loss on the local economy. Elsewhere, there was widespread concern about the independence of the kirk, and possible tax rises. As the Treaty passed through the Scottish Parliament, opposition was voiced by petitions from shires, burghs, presbyteries and parishes. The Convention of Royal Burghs claimed we are not against an honourable and safe union with England, [... but] the condition of the people of Scotland, (cannot be) improved without a Scots Parliament. Not one petition in favour of Union was received by Parliament. On the day the treaty was signed, the carillonneur in St Giles Cathedral, Edinburgh, rang the bells in the tune "Why should I be so sad on my wedding day?" Threats of widespread civil unrest resulted in Parliament imposing martial law. The Union was carried by members of the Scottish elite against the wishes of the great majority. The Scottish population was overwhelmingly against the union with England, and virtually all of the print discourses of 1699-1706 spoke against incorporating union, creating the conditions for wide spread rejection of the treaty in 1706 and 1707. Country party tracts condemned English influence within the existing framework of the Union of the Crowns and asserted the need to renegotiate this union. During this period, the Darien failure, the succession issue and the Worcester seizure all provided opportunities for Scottish writers to attack the Court Party as unpatriotic and reaffirm the need to fight for true interests of Scotland. According to Scottish historian William Ferguson, the Acts of Union were a 'political job' by England that was achieved by economic incentives, patronage and bribery to secure the passage of the Union treaty in the Scottish Parliament in order satisfy English political imperatives, with the union being unacceptable to the Scottish people including both the Jacobites and Covenanters. The differences between Scottish were "subsumed by the same sort of patriotism or nationalism that first appeared in the Declaration of Arbroath of 1320." Ferguson provides the well-timed payments of salary arrears to members of Parliament as proof of bribery and argues that the Scottish people had been betrayed by their Parliament. Ireland, though a kingdom under the same crown, was not included in the union. It remained a separate kingdom, unrepresented in Parliament, and was legally subordinate to Great Britain until the Renunciation Act of 1783. In July 1707 each House of the Parliament of Ireland passed a congratulatory address to Queen Anne, praying that "May God put it in your royal heart to add greater strength and lustre to your crown, by a still more comprehensive Union". The British government did not respond to the invitation and an equal union between Great Britain and Ireland was out of consideration until the 1790s. The union with Ireland finally came about on 1 January 1801. Treaty and passage of the 1707 Acts Deeper political integration had been a key policy of Queen Anne from the time she acceded to the throne in 1702. Under the aegis of the Queen and her ministers in both kingdoms, the parliaments of England and Scotland agreed to participate in fresh negotiations for a union treaty in 1705. Both countries appointed 31 commissioners to conduct the negotiations. Most of the Scottish commissioners favoured union, and about half were government ministers and other officials. At the head of the list was Queensberry, and the Lord Chancellor of Scotland, the Earl of Seafield. The English commissioners included the Lord High Treasurer, the Earl of Godolphin, the Lord Keeper, Baron Cowper, and a large number of Whigs who supported union. Tories were not in favour of union and only one was represented among the commissioners. Negotiations between the English and Scottish commissioners took place between 16 April and 22 July 1706 at the Cockpit in London. Each side had its own particular concerns. Within a few days, and with only one face to face meeting of all 62 commissioners, England had gained a guarantee that the Hanoverian dynasty would succeed Queen Anne to the Scottish crown, and Scotland received a guarantee of access to colonial markets, in the hope that they would be placed on an equal footing in terms of trade. After negotiations ended in July 1706, the acts had to be ratified by both Parliaments. In Scotland, about 100 of the 227 members of the Parliament of Scotland were supportive of the Court Party. For extra votes the pro-court side could rely on about 25 members of the Squadrone Volante, led by the Marquess of Montrose and the Duke of Roxburghe. Opponents of the court were generally known as the Country party, and included various factions and individuals such as the Duke of Hamilton, Lord Belhaven and Andrew Fletcher of Saltoun, who spoke forcefully and passionately against the union, when the Scottish Parliament began its debate on the act on 3 October 1706, but the deal had already been done. The Court party enjoyed significant funding from England and the Treasury and included many who had accumulated debts following the Darien Disaster. The Act ratifying the Treaty of Union was finally carried in the Parliament of Scotland by 110 votes to 69 on 16 January 1707, with a number of key amendments. News of the ratification and of the amendments was received in Westminster, where the Act was passed quickly through both Houses and received the royal assent on 6 March. Though the English Act was later in date, it bore the year '1706' while Scotland's was '1707', as the legal year in England began only on 25 March. In Scotland, the Duke of Queensberry was largely responsible for the successful passage of the Union act by the Parliament of Scotland. In Scotland, he also received much criticism from local residents, but in England he was cheered for his action. He had personally received around half of the funding awarded by the Westminster Treasury for himself. In April 1707, he travelled to London to attend celebrations at the royal court, and was greeted by groups of noblemen and gentry lined along the road. From Barnet, the route was lined with crowds of cheering people, and once he reached London a huge crowd had formed. On 17 April, the Duke was gratefully received by the Queen at Kensington Palace. The Treaty of Union, agreed between representatives of the Parliament of England and the Parliament of Scotland in 1706, consisted of 25 articles, 15 of which were economic in nature. In Scotland, each article was voted on separately and several clauses in articles were delegated to specialised subcommittees. Article 1 of the treaty was based on the political principle of an incorporating union and this was secured by a majority of 116 votes to 83 on 4 November 1706. To minimise the opposition of the Church of Scotland, an Act was also passed to secure the Presbyterian establishment of the Church, after which the Church stopped its open opposition, although hostility remained at lower levels of the clergy. The treaty as a whole was finally ratified on 16 January 1707 by a majority of 110 votes to 69. The two Acts incorporated provisions for Scotland to send representative peers from the Peerage of Scotland to sit in the House of Lords. It guaranteed that the Church of Scotland would remain the established church in Scotland, that the Court of Session would "remain in all time coming within Scotland", and that Scots law would "remain in the same force as before". Other provisions included the restatement of the Act of Settlement 1701 and the ban on Roman Catholics from taking the throne. It also created a customs union and monetary union. The Act provided that any "laws and statutes" that were "contrary to or inconsistent with the terms" of the Act would "cease and become void". The Scottish Parliament also passed the Protestant Religion and Presbyterian Church Act 1707 guaranteeing the status of the Presbyterian Church of Scotland. The English Parliament passed a similar Act, 6 Anne c.8. Soon after the Union, the Act 6 Anne c.40—later named the Union with Scotland (Amendment) Act 1707—united the English and Scottish Privy Councils and decentralised Scottish administration by appointing justices of the peace in each shire to carry out administration. In effect it took the day-to-day government of Scotland out of the hands of politicians and into those of the College of Justice. On 18 December 1707 the Act for better Securing the Duties of East India Goods was passed which extended the monopoly of the East India Company to Scotland. Scotland benefited, says historian G.N. Clark, gaining "freedom of trade with England and the colonies" as well as "a great expansion of markets". The agreement guaranteed the permanent status of the Presbyterian church in Scotland, and the separate system of laws and courts in Scotland. Clark argued that in exchange for the financial benefits and bribes that England bestowed, what it gained was of inestimable value. Scotland accepted the Hanoverian succession and gave up her power of threatening England's military security and complicating her commercial relations ... The sweeping successes of the eighteenth-century wars owed much to the new unity of the two nations. By the time Samuel Johnson and James Boswell made their tour in 1773, recorded in A Journey to the Western Islands of Scotland, Johnson noted that Scotland was "a nation of which the commerce is hourly extending, and the wealth increasing" and in particular that Glasgow had become one of the greatest cities of Britain. Scottish historian Christopher Smout notes that prior to the Union of the Crowns, the Scottish economy had been flourishing completely independently of the English one, with little to no interaction between each other. Developing a closer economic partnership with England was unsustainable, and Scotland's main trade partner was continental Europe, especially the Netherlands, where Scotland could trade its wool and fish for luxurious imports such as iron, spices or wine. Scotland and England were generally hostile to each other and were often at war, and the alliance with France gave Scotland privileges that further encouraged developing cultural and economic ties with the continent rather than England. The union of 1603 only served the political and dynastic ambitions of King James and was detrimental to Scotland economically – exports that Scotland offered were largely irrelevant to English economy, and while the Privy Council of Scotland did keep its ability to manage internal economic policy, the foreign policy of Scotland was not in hands of England. This limited Scotland's hitherto expansive trade with continental Europe, and forced it into English wars. While the Scottish economy already suffered because of English wars with France and Spain in 1620s, the civil wars in England had a particularly disastrous effect on Scotland and left it relatively impoverished as a result. The economy would slowly recover after that, but it came at the cost of being increasingly dependent on trade with England. A power struggle developed between Scotland and England in 1680s, as Scotland recovered from the political turmoil and set on its own economic ambitions, which London considered a threat to its dominant and well-established position. English wars with continental powers undermined Scottish trade with France and the Netherlands, countries that used to be the Scotland's main trade partners before the union, and the English Navigation Acts severely limited Scottish ability to trade by sea, and made the Scottish ambitions to expand the trade beyond Europe unachievable. Opinion in Scotland at the time was that England was sabotaging Scottish economic expansion. The frustration caused by economic and political rivalry with England led to the Darien scheme - an unsuccessful to establish a Scottish colony in the Gulf of Darién. Christopher Smout argues that the scheme was successfully sabotaged by England in various ways - it was seen as a threat to the privileged position of the East India Company, and as such England did everything to ensure the plan's failure via political and diplomatic overtures to prevent the Netherlands and Hamburg from investing into the scheme while also refusing to assist the settlers in any way. Following the disastrous failure of the scheme, Scottish economy seemed to be on the brink of collapse, but ultimately Scotland was able to recover from it fairly quickly. By 1703, Scottish government was highly disillusioned and unsatisfied with the union, and many believed that the only way to let Scottish economy flourish was to separate from England. Fletcher of Saltoun called Scotland 'totally neglected, like a farm managed by servants not under the eye of the master', and the failure of the Darien Scheme was commonly attributed to English sabotage. Scottish parliament would try to establish its autonomy from England with 1704 Act of Security, which provoked a retaliation from England - Scottish ministers were bribed, and Alien Act 1705 was passed. According to the Alien Act, unless Scotland appointed commissioners to negotiate for union by Christmas, every Scot in England would be treated as an alien, leading to the confiscation of their English estates. Additionally, Scottish wares were to be banned from England. Christopher Smout notes that England desired to expand its influence by annexing Scotland: In sum, England was now seeking Parliamentary Union for political reasons at a moment when the Scots had become dissatisfied with Regal Union for economic reasons: and one of the main weapons chosen by the English to enforce their will was the threat of economic sanctions. The repeal of the Alien Act before it could come into force scarcely reduced its menace: a big stick is a big stick, even if it is replaced in the cupboard unused. The act sparked vehement anti-English sentiment in Scotland, and made the already hostile Scottish public even more opposed to England: The crew of an English East Indiaman, the Worcester, that had put into Leith to escape a storm was arrested on a spurious charge of piracy and executed after a parody of a trial, victims of a wave of anti-English hysteria which the Ministers of the Crown dared not be seen to oppose. As late as June, the Scottish Uniornist Cockburn of Ormiston declared he could not find ten men in Parliament willing to join England in a full Union - an exaggeration no doubt, but an indication of the contemporary force of feeling. The Scottish economy was now facing a crisis, and the parliament was polarised into a pro-union and anti-union factions, with the former led by Daniel Defoe. The unionists stressed how important trade with England is to the Scottish economy, and portrayed trade with continental Europe as not beneficial, or nowhere as profitable as trading with England. They argued that the Scottish economy could survive by trading with England, and sanctions that would result from the Alien Act would collapse the economy. For Defoe, joining the union would not only prevent the Alien Act, but would also remove additional limitations and regulations, which could lead Scotland to prosperity. Anti-unionists questioned the English goodwill and criticised the unionist faction for submitting to the English blackmail. They argued that Scotland could make a recovery by trading with the Netherlands, Spain and Norway, with the diverse European markets allowing Scotland to diversify its own industries as well. They noted that the union would make Scotland unable to conduct independent trade policy, meaning that any possibility to remove the flaws in Scottish economy would be gone forever, which would turn Scotland into a "mere satellite of the richer kingdom". Ultimately, Scottish ministers voted in favour of the union, which was against the public opinion, as the Scottish population at the time was overwhelmingly against any union with England. Many considered themselves betrayed by their own elite, and Smout argues that the union bill was only able to pass thanks to the English bribery. The Scottish Government held a number of commemorative events through the year including an education project led by the Royal Commission on the Ancient and Historical Monuments of Scotland, an exhibition of Union-related objects and documents at the National Museums of Scotland and an exhibition of portraits of people associated with the Union at the National Galleries of Scotland. Scottish voting records - Acts of Union 1800 (King of Great Britain with Kingdom of Ireland) - English independence - List of treaties - MacCormick v Lord Advocate - Parliament of the United Kingdom - Political union - Real union - Scottish independence - Unionism in Scotland - Welsh independence - The citation of this Act by this short title was authorised by section 1 of, and Schedule 1 to, the Short Titles Act 1896. Due to the repeal of those provisions, it is now authorised by section 19(2) of the Interpretation Act 1978. - The citation of this Act by this short title was authorised by the Statute Law Revision (Scotland) Act 1964, section 2 and Schedule 2. Due to the repeal of those provisions it is now authorised by section 19(2) of the Interpretation Act 1978. - Article I of the Treaty of Union - "House of Commons Journal Volume 1: 31 March 1607". Archived from the original on 31 October 2020. Retrieved 27 October 2020. - Act of Union 1707, Article 3 - "Glossary". archive2021.parliament.scot. 20 May 2010. Retrieved 14 January 2023. - Larkin & Hughes 1973, p. 19. - Lockyer 1998, pp. 51–52. - Lockyer 1998, pp. 54–59. - Stephen 2010, pp. 55–58. - McDonald 1998, pp. 75–76. - Kaplan 1970, pp. 50–70. - Robertson 2014, p. 125. - Harris 2015, pp. 53–54. - Morrill 1990, p. 162. - "Constitution.org". Archived from the original on 22 February 2020. Retrieved 23 April 2009. - The 1657 Act's long title was An Act and Declaration touching several Acts and Ordinances made since 20 April 1653, and before 3 September 1654, and other Acts - Parliament.uk Archived 12 October 2008 at the Wayback Machine - MacIntosh 2007, pp. 79–87. - Whatley 2001, p. 95. - Lynch 1992, p. 305. - Harris 2007, pp. 404–406. - Whatley 2006, p. 91. - Mitchison 2002, pp. 301–302. - Richards 2004, p. 79. - United Kingdom Gross Domestic Product deflator figures follow the Measuring Worth "consistent series" supplied in Thomas, Ryland; Williamson, Samuel H. (2018). "What Was the U.K. GDP Then?". MeasuringWorth. Retrieved 2 February 2020. - Mitchison 2002, p. 314. - Munck 2005, pp. 429–431. - Jackson 2003, pp. 38–54. - Horwitz 1986, pp. 10–11. - Lynch 1992, pp. 300–303. - MacPherson, Hamish (27 September 2020). "How the Act of Union came about through a corrupt fixed deal in 1706". The National. Archived from the original on 27 September 2020. Retrieved 27 September 2020. - "Ratification, October 1706 – March 1707". Parliament of the United Kingdom. Archived from the original on 22 September 2020. Retrieved 27 September 2020. - Cullen 2010, p. 117. - Whatley 2001, p. 48. - Watt 2007, p. ?. - Whatley 1989, pp. 160–165. - Devine, Thomas Martin (5 July 2012). The Scottish nation: a modern history. London: Penguin. ISBN 978-0-7181-9673-8. OCLC 1004568536. - "Scottish Referendums". BBC. Archived from the original on 12 November 2020. Retrieved 16 March 2016. - Bambery 2014, p. ?. - The Humble Address of the Commissioners to the General Convention of the Royal Burrows of this Ancient Kingdom Convened the Twenty-Ninth of October 1706, at Edinburgh. - Notes by John Purser to CD Scotland's Music, Facts about Edinburgh Archived 7 January 2021 at the Wayback Machine. - Bowie, Karin (2003). "Public Opinion, Popular Politics and the Union of 1707". The Scottish Historical Review. Edinburgh University Press. 82 (214): 226–260. doi:10.3366/shr.2003.82.2.226. JSTOR 25529719. - The Parliamentary Register; Or, History of the Proceedings and Debates of the Houses of Lords and Commons, page 448 - Journals of the Irish Commons, vol. iii. p. 421 - "The commissioners". UK Parliament website. 2007. Archived from the original on 19 June 2009. Retrieved 5 February 2013. - "The course of negotiations". UK Parliament website. 2007. Archived from the original on 21 July 2009. Retrieved 5 February 2013. - "Ratification". UK parliament website. 2007. Archived from the original on 19 June 2009. Retrieved 5 February 2013. - Macrae, The Rev. Alexander: Scotland Since the Union' (1902) - "1 May 1707 – the Union comes into effect". UK Parliament website. 2007. Archived from the original on 19 June 2009. Retrieved 5 February 2013. - Riley 1969, pp. 523–524. - G.N. Clark, The Later Stuarts, 1660–1714 (2nd ed. 1956) pp 290–93. - Gordon Brown (2014). My Scotland, Our Britain: A Future Worth Sharing. Simon & Schuster UK. p. 150. ISBN 9781471137518. - Smout, Thomas Christopher (1964). "I. The Economic Background". The Anglo-Scottish Union of 1707. The Economic History Review. Vol. 16. Wiley on behalf of the Economic History Society. pp. 455–467. JSTOR 2592848. - House of Lords – Written answers, 6 November 2006, TheyWorkForYou.com - Announced by the Scottish Culture Minister, Patricia Ferguson, 9 November 2006 Sources and further reading - Bambery, Chris (2014). A People's History of Scotland. Verso. ISBN 978-1786637871. - Campbell, R. H. "The Anglo-Scottish Union of 1707. II. The Economic Consequences". Economic History Review vol. 16, no. 3, 1964, pp. 468–477 online Archived 2 November 2020 at the Wayback Machine - Cullen, K. J. (2010). Famine in Scotland: The "Ill Years" of the 1690s. Edinburgh University Press. ISBN 978-0748638871. - Harris, Tim (2007). Revolution: The Great Crisis of the British Monarchy, 1685–1720. Penguin. ISBN 978-0141016528. - Harris, Tim (2015). Rebellion: Britain's First Stuart Kings, 1567–1642. OUP Oxford. ISBN 978-0198743118. - Horwitz, Henry (1986). Parliament, Policy and Politics in the Reign of William III. MUP. ISBN 978-0719006616. - Jackson, Clare (2003). Restoration Scotland, 1660–1690: Royalist Politics, Religion and Ideas. Boydell Press. ISBN 978-0851159300. - Kaplan, Lawrence (May 1970). "Steps to War: The Scots and Parliament, 1642–1643". Journal of British Studies. 9 (2): 50–70. doi:10.1086/385591. JSTOR 175155. S2CID 145723008. - Larkin, James F.; Hughes, Paul L., eds. (1973). Stuart Royal Proclamations: Volume I. Clarendon Press. - Lynch, Michael (1992). Scotland: a New History. Pimlico Publishing. ISBN 978-0712698931. - Lockyer, R (1998). James VI and I. London: Addison Wesley Longman. ISBN 978-0-582-27962-9. - MacIntosh, Gillian (2007). Scottish Parliament under Charles II, 1660–1685. Edinburgh University Press. ISBN 978-0748624577. - McDonald, Alan (1998). The Jacobean Kirk, 1567–1625: Sovereignty, Polity and Liturgy. Routledge. ISBN 978-1859283738. - Mitchison, Rosalind (2002). A History of Scotland. Routledge. ISBN 978-0415278805. - Morrill, John (1990). Oliver Cromwell and the English Revolution. Longman. ISBN 978-0582016750. - Munck, Thomas (2005). Seventeenth-Century Europe: State, Conflict and Social Order in Europe 1598–1700. Palgrave. ISBN 978-1403936196. - Richards, E (2004). OBritannia's Children: Emigration from England, Scotland, Wales and Ireland since 1600. Continuum. ISBN 1852854413. - Riley, PJW (1969). "The Union of 1707 as an Episode in English Politics". The English Historical Review. 84 (332): 498–527. JSTOR 562482. - Robertson, Barry (2014). Royalists at War in Scotland and Ireland, 1638–1650. Routledge. ISBN 978-1317061069. - Smout, T. C. "The Anglo-Scottish Union of 1707. I. The Economic Background". Economic History Review vol. 16, no. 3, 1964, pp. 455–467. online Archived 13 April 2020 at the Wayback Machine - Stephen, Jeffrey (January 2010). "Scottish Nationalism and Stuart Unionism". Journal of British Studies. 49 (1, Scottish Special). doi:10.1086/644534. S2CID 144730991. - Watt, Douglas (2007). The Price of Scotland: Darien, Union and the wealth of nations. Luath Press. ISBN 978-1906307097. - Whatley, C (2001). Bought and sold for English Gold? Explaining the Union of 1707. East Linton: Tuckwell Press. ISBN 978-1-86232-140-3. - Whatley, C (2006). The Scots and the Union. Edinburgh University Press. ISBN 978-0-7486-1685-5. - Whatley, Christopher (1989). "Economic Causes and Consequences of the Union of 1707: A Survey". Scottish Historical Review. 68 (186). - Defoe, Daniel. A tour thro' the Whole Island of Great Britain, 1724–27 - Defoe, Daniel. The Letters of Daniel Defoe, GH Healey editor. Oxford: 1955. - Fletcher, Andrew (Saltoun). An Account of a Conversation - Lockhart, George, "The Lockhart Papers", 1702–1728 - The full text of Act of Union 1707 at Wikisource - Union with England Act and Union with Scotland Act – Full original text - Treaty of Union and the Darien Experiment, University of Guelph, McLaughlin Library, Library and Archives Canada - Text of the Union with Scotland Act 1706 as in force today (including any amendments) within the United Kingdom, from legislation.gov.uk. - Text of the Union with England Act 1707 as in force today (including any amendments) within the United Kingdom, from legislation.gov.uk. - Union with England Act 1707, from Records of the Parliaments of Scotland - Image of original act from the Parliamentary Archives website
What Are Data Structures and Algorithms? More precisely, a data structure is a collection of data values, the relationships among them, and the functions or operations that can be applied to the data Technically speaking, an algorithm is defined as a set of rules or a step-by-step procedure that are to be executed in a specific order to get the desired output. The formal definition of an algorithm is a finite set of steps carried out in a specific time for specific problem-solving operations, especially by a Computer. Algorithms are independent of programming languages and are usually represented by using flowcharts or pseudocode. Characteristics of an Algorithm A fact to be noted is that not all sets of instructions or procedures are an algorithm. A set of instructions should have all the relevant characteristics to qualify as an algorithm. The characteristics of algorithm are as follows- - Unambiguous– An algorithm should be clear and simple in nature and lead to a meaningful outcome i.e. they should be unambiguous. - Input– It should have some input values. - Output– Every algorithm should have well-defined outputs - Finiteness– The steps of an algorithm should be countable and it should terminate after the specified number of steps. - Effectiveness– Each step of the algorithm should be effective and efficient enough to produce results. The effectiveness of an algorithm can be evaluated with the help of two important parameters- - Time Complexity-It is nothing but the amount of time taken by the computer to run the algorithm. We can also call it the computational complexity of an algorithm. It can either be best-case, average-case or worst-case. We always aim for the best-case for effectiveness. - Space Complexity-It refers to the amount of computational memory needed to solve an instance of the problem statement.The lower the space complexity of an algorithm, the faster the algorithm will work. - Language Independent– Algorithms should be language independent. In other words, the algorithm should work for all programming languages and give the same output. Data Flow of an Algorith - Problem- The problem can be any real world or a programmable problem. The problem statement usually gives the programmer an idea of the issue at hand, the available resources and the motivation to come with a plan to solve it. - Algorithm- After analysing the problem, the programmer designs the step by step procedure to solve the problem efficiently. This procedure is the algorithm. - Input- The algorithm is designed and the relevant inputs are supplied. - Processing Unit- The processing unit receives these inputs and processes them as per the designed algorithm - Output- Finally, after the processing is complete, we receive the favourable output of our problem statement. Why do we Need Algorithms? Primarily, we need algorithms for the following two reasons- - Scalability– When we have big real-world problems, we cannot tackle them on the macro level. We need to break them down into smaller steps so that the problem can be analyzed easily. Thus, algorithms facilitate scalability - Performance– It is never easy to break down big problems into smaller modules. But algorithms help us achieve this. They help us make the problem feasible and provide efficient performance driven solutions How to Write an Algorithm? A simple Google search would tell you that there is no one “right way” to bake a cake. There are countless recipes available online- devised and tested by bakers around the world. Likewise, there are no predefined standards on how to write an algorithm. The way we write algorithms is heavily influenced by the problem statement and the resources available. The common construct that is widely followed in case of algorithms is the use of pseudocode. Factors of an Algorithm While designing an algorithm, we must consider the following factors- - Modularity- If a big problem can be easily broken down into smaller ones, it facilitates modularity. - Correctness- The analysis of the problem statement and consequently the algorithm should be correct. The algorithm should also work correctly for all possible test cases of the problem at hand. - Maintainability- The algorithm should be designed in such a way that it should be easy to maintain and if we wish to refine it at some point. - Functionality- The steps of an algorithm should successfully solve a real world problem. - User-friendly- It should be easily understood by programmers. - Simplicity- It should be the simplest possible solution to a problem. By simplicity, we refer to the fact that the algorithm should have the best-case time complexity. - Extensible- It should be extensible i.e. the algorithm should facilitate reusability. Let’s start with a simple example of an algorithm- Example 1: Design an algorithm to accept three numbers and print their sum. Step 2- Declare variables x,y,z and sum Step 3- Read the value of x,y and z Step 4- Add x,y and z Step 5-Store the output of Step 4 in sum Step 6-Print sum Step 7- STOP Example 2: Design an algorithm to find the factorial of a number and print it. Step 2- Declare variables fact, num and i Step 3- Initialize variables as: fact->1 and i->1 Step 4- Read the value of num Step 5-Repeat the steps until num=i - 5.1- fact->fact*i - 5.2- i->i+1 Step 6- Print fact Step 7- STOP Importance of Algorithms The importance of algorithms can be classified as- - Theoretical Importance- The best way to deal with any real-world problem is to break them down into smaller modules.The theoretical knowledge from pre-existing algorithms often help us to do so. - Practical Importance- Just designing an algorithm theoretically or using some aspects of pre-existing ones is not enough. The real-world problems can only be considered to be solved if we manage to get practical results from it Hence, an algorithm can be said to have both theoretical and practical importance. Cheatsheet for Algorithm In Data Structure Types of Algorithms An algorithm is a sequential series of steps and processes for solving a problem. While there can be different types of algorithms for solving different problems, we consider the following algorithms to be important in programming. As a starting point, here are the types of Algorithms The linear search algorithm is also known as a sequential search algorithm and it is the simplest of all search algorithms. The linear search involves traversing the list completely and matching each element with the item whose location you are looking for. An item's location is returned if a match is found; otherwise, NULL is returned. A binary search is a search algorithm that divides the search interval in half repeatedly to search a sorted array. Divide and conquer is the underlying principle of a binary search. It is imperative that the data collection should be sorted in order for this algorithm to work properly. A binary search compares the middlemost item of a collection in order to find a particular item. An index of the item is returned if there is a match. The item is then looked up in the sub-array to the left of the middle item if the middle item exceeds the item. The item is otherwise searched for in the sub-array to the right of the middle item. The same process is repeated on the sub-array until the subarray is reduced to zero. 1. Bubble Sort In Bubble Sort, an element is swapped repeatedly until it is in the sorted or intended order. The movement of array elements is similar to the movement of air bubbles in water, which is why it is called bubble sort. Similar to bubbles in water rising to the surface, array elements in bubble sort move to the end each time they are iterated. Insertion sort involves placing an unsorted item at its proper place in each iteration of a sorting algorithm. It is similar to how we sort the cards in our hands in a card game. First, we select an unsorted card, assuming that the first card is already sorted. The unsorted card should be put on the right if it is greater than the card in hand, otherwise, it should be placed on the left. A similar process is followed in sorting other unsorted cards. 3. Quick sort The Quicksort algorithm involves divide-and-conquer. In this method, one element is selected as the pivot, and the others are divided into two sub-arrays based on whether they are less or greater than the pivot. This method is therefore sometimes referred to as partition-exchange sort. This can be done in place, with only a little amount of additional RAM required for sorting.. Despite its simplicity and straight forward nature, selection sort is a powerful sorting algorithm. By comparing the items in place, selection-based sorting divides the list into two sections, left and right of the sorted items. There is no data in the sorted section, while all the data is in the unsorted section. A small list can be sorted using selection sort. 5. Merge sort Basically, merge sort splits the input into two halves, repeats the process on both halves, and merges the sorted halves together. From top to bottom, the algorithm divides the list into progressively smaller pieces until only the individual elements remain. It then moves back up to ensure that the merged lists are sorted. Using this algorithm, elements will be sorted by the number of times each element occurs. It is a fast and reliable method to sort data. The algorithm calculates how many elements are associated with each unique value. Afterward, this data is sorted according to specific mathematical calculations. Radix sort is a sorting algorithm that groups the digits of the same place value together before sorting the elements. Following that, sort the elements in order of increasing/decreasing value. Let's say we have an array of 6 elements. As a first step, we will sort the elements by place value. Our next step will be to sort elements according to the tenth place. The process continues until the last significant place is reached. 8. Bucket Sort Using bucket sort, the elements of an array are divided into several groups called buckets. The buckets are then sorted by applying any of the available sorting algorithms or by recursively applying the same bucket algorithm. The sorted buckets are then concatenated to create a final sorted array. 9. Shell Sort The sorting algorithm is an extended version of insertion sort; it sorts the elements that are far apart at first, then it reduces the distance between them at the end. The gap between elements is called an interval. Knuth's formula can be used to calculate this interval. 10. Heap Sort The binary heap data structure is used for heap sorting, which is a comparison-based sorting technique . In heap sort, each element in the list is eliminated from the heap part of the list, then it is inserted into the sorted part of the list. Recursion is the basis for this kind of algorithm. Using recursion, a problem is broken into sub-problems and calls itself repeatedly until an underlying condition is able to solve it. Divide And Conquer Algorithm The divide and conquer algorithm divides the problem into two sections, the first section dividing it into subproblems of the same type. Section two involves solving smaller problems independently, combining the results, and calculating the final answer. Dynamic Programming Algorithms An algorithm of this type is also referred to as a memoization algorithm because it stores the previously calculated result in order to avoid recalculating it. In dynamic programming, we divide complex problems into smaller overlapping subproblems and store the results for later use in Dynamic Programming. A greedy algorithm builds solution part by part. In order to decide which part to proceed to next, we look at the benefit it provides immediately. Previous decisions are never taken into account. By using backtracking algorithm, problems are solved incrementally, i.e. they are solved recursively by adding pieces one at a time, and removing the solutions that do not meet the constraints of the problem at any point in time. A hashing algorithm operates the same as a searching algorithm, but it includes an index with an ID. We assign a key to specific data when we hash it. Issues While Working on Algorithms The most common issue that we face while working on algorithms is- “How do I design it?” Not all problems will have an easy solution and along with that, we need the solutions to be efficient as well. Sometimes, this may cause the programmers to feel stuck. By now, you have successfully gathered a clear idea about- - What is an algorithm? - Characteristics of an algorithm - The how and why of an algorithm - The importance and issues - Some easy to understand examples The next time you do a task now, you will try to relate it with an algorithm. So start exploring and keep an eye out for learning more!
Scientific Method Worksheet Pdf We provide students with a series of worksheets below to introduce them to the basic process. Scientific method worksheet pdf. See more ideas about scientific method worksheet, scientific method, scientific. 7th grade scientific method worksheet pdf Don’t let the scientific method overwhelm you. It is a process that is used to find answers to questions about the world around us. However, his notes got mixed up. Exploring the scientific method the scientific method is a process that scientists use to better understand the world around them. Form your hypothesis and step 4: She presented her information to the group. Use the poster to list the steps of order using the scientific method. Students write out the steps about their science experiment on their worksheet. Scientific method story worksheet analyzing the elements of a scientific method read the following story and then answer the questions. However, they all begin with the We included pictures that correlate to the poster, but after they have memorized the scientific method, it can help remind them of the steps. The scientific method is a series of techniques used to examine phenomena. The scientific method is a systematic way of studying the world in a scientific manner. In advance of preaching about scientific method practice worksheet, please recognize that education is actually all of our step to an even better the day after tomorrow, and also mastering won’t just end after a classes bell rings.this remaining mentioned, many of us provide a a number of basic still helpful content articles plus web templates created suitable for virtually any helpful purpose. You and your friend are walldng along a beach in maine on january 15, at 8:00 am. “scientific method” activity 2 directions: - Complementary And Supplementary Angles Worksheet Grade 3 - Comparing Numbers Worksheets For Kindergarten Pdf - Congruent Triangles Proofs Calculator - Congruent Triangles Meaning In Urdu - Daily Routine Worksheet For Grade 1 - Congruent Triangles Worksheet Tes - Collective Nouns Worksheet For Class 2 - Comparing Mitosis And Meiosis Worksheet Answer Key Biology If8765 - Daily Routine Worksheet For Grade 5 - Comparing Adverbs Worksheets For Grade 3 - Counting Worksheets 1 20 Printable - Compound Inequalities Worksheet Algebra 1 - Daily Routine Worksheets For Preschool - Clothes Worksheet For Kindergarten - Density Problems Worksheet With Answers - Congruent Triangles Proofs Worksheet - Congruent Triangles Non Calculator Answers - Density Problems Worksheet 1 Answer Key - Clothing Worksheets 1st Grade - Daily Routine Worksheet British Council
- 1 Definition - 2 Indefinite integral identities - 3 The Substitution Rule - 4 Integration by Parts Now recall that F is said to be an antiderivative of f if . However, F is not the only antiderivative. We can add any constant to F without changing the derivative. With this, we define the indefinite integral as follows: The function , the function being integrated, is known as the integrand. Note that the indefinite integral yields a family of functions. Since the derivative of is , the general antiderivative of is plus a constant. Thus, Example: Finding antiderivatives Let's take a look at . How would we go about finding the integral of this function? Recall the rule from differentiation that In our circumstance, we have: This is a start! We now know that the function we seek will have a power of 3 in it. How would we get the constant of 6? Well, Thus, we say that is an antiderivative of . Indefinite integral identities Basic Properties of Indefinite Integrals Indefinite integrals of Polynomials Say we are given a function of the form, , and would like to determine the antiderivative of f. Considering that we have the following rule for indefinite integrals: Integral of the Inverse function To integrate , we should first remember Therefore, since is the derivative of we can conclude that Note that the polynomial integration rule does not apply when the exponent is -1. This technique of integration must be used instead. Since the argument of the natural logarithm function must be positive (on the real line), the absolute value signs are added around its argument to ensure that the argument is positive. Integral of the Exponential function we see that is its own antiderivative. This allows us to find the integral of an exponential function: Integral of Sine and Cosine So sin x is an antiderivative of cos x and -cos x is an antiderivative of sin x. Hence we get the following rules for integrating sin x and cos x We will find how to integrate more complicated trigonometric functions in the chapter on integration techniques. Suppose we want to integrate the function . An application of the sum rule from above allows us to use the power rule and our rule for integrating as follows, The Substitution Rule The substitution rule is a valuable asset in the toolbox of any integration greasemonkey. It is essentially the chain rule (a differentiation technique you should be familiar with) in reverse. First, let's take a look at an example: Suppose we want to find . That is, we want to find a function such that its derivative equals . Stated yet another way, we want to find an antiderivative of . Since differentiates to , as a first guess we might try the function . But by the Chain Rule, Which is almost what we want apart from the fact that there is an extra factor of 2 in front. But this is easily dealt with because we can divide by a constant (in this case 2). So, Thus, we have discovered a function, , whose derivative is . That is, F is an antiderivative of . This gives us In fact, this technique will work for more general integrands. Suppose u is a differentiable function. Then to evaluate we just have to notice that by the Chain Rule As long as is continuous we have that Now the right hand side of this equation is just the integral of but with respect to u. If we write u instead of u(x) this becomes So, for instance, if we have worked out that General Substitution Rule Now there was nothing special about using the cosine function in the discussion above, and it could be replaced by any other function. Doing this gives us the substitution rule for indefinite integrals: Notice that it looks like you can "cancel" in the expression to leave just a . This does not really make any sense because is not a fraction. But it's a good way to remember the substitution rule. The following example shows how powerful a technique substitution can be. At first glance the following integral seems intractable, but after a little simplification, it's possible to tackle using substitution. We will show that First, we re-write the integral: Now we preform the following substitution: Integration by Parts Integration by parts is another powerful tool for integration. It was mentioned above that one could consider integration by substitution as an application of the chain rule in reverse. In a similar manner, one may consider integration by parts as the product rule in reverse. General Integration by Parts to set the f(x) and g(x) we need to follow the rule called I.L.A.T.E. ILATE defines the order in which we must set the f(x) - I for inverse trigonometric function - L for log functions - A for algebraic functions - T for trigonometric functions - E for exponential function f(x) and g(x) must be in the order of ILATE or else your final answers will not match with the main key Here we let: - , so that , - , so that . In this example we will have to use integration by parts twice. Here we let - , so that , - , so that . Now to calculate the last integral we use integration by parts again. Let - , so that , - , so that and integrating by parts gives So, finally we obtain The trick here is to write this integral as - so , - so . Then using integration by parts, Again the trick here is to write the integrand as . Then let - u = arctan(x); du = 1/(1+x2) dx - v = x; dv = 1·dx so using integration by parts, This example uses integration by parts twice. First let, - u = ex; thus du = exdx - dv = cos(x)dx; thus v = sin(x) Now, to evaluate the remaining integral, we use integration by parts again, with - u = ex; du = exdx - v = -cos(x); dv = sin(x)dx Putting these together, we have Notice that the same integral shows up on both sides of this equation, but with opposite signs. The integral does not cancel; it doubles when we add the integral to both sides to get

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