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Adam Smith Where there is no property, or at least none that exceeds the value of two or three days' labour, civil government is not so necessary. Civil government supposes a certain subordination. But as the necessity of civil government gradually grows up with the acquisition of valuable property, so the principal causes which naturally introduce subordination gradually grow up with the growth of that valuable property. (...) Men of inferior wealth combine to defend those of superior wealth in the possession of their property, in order that men of superior wealth may combine to defend them in the possession of theirs. All the inferior shepherds and herdsmen feel that the security of their own herds and flocks depends upon the security of those of the great shepherd or herdsman; that the maintenance of their lesser authority depends upon that of his greater authority, and that upon their subordination to him depends his power of keeping their inferiors in subordination to them. They constitute a sort of little nobility, who feel themselves interested to defend the property and to support the authority of their own little sovereign in order that he may be able to defend their property and to support their authority. Civil government, so far as it is instituted for the security of property, is in reality instituted for the defence of the rich against the poor, or of those who have some property against those who have none at all | https://en.wikipedia.org/wiki?curid=1814 | 515,270 |
RSCS It spanned North America (in Canada it was known as NetNorth), Europe (as EARN), India (TIFR) and some Persian Gulf states (as GulfNet). BITNET was also very popular in other parts of the world, especially in South America, where about 200 nodes were implemented and heavily used in the late 1980s and early 1990s. R. J. Creasy described as an operating system and considered it an essential component of the VM/370 Time-Sharing System. "The Virtual Machine Facility/370, VM/370 for short, is a convenient name for three different operating systems: the Control Program (CP), the Conversational Monitor System (CMS), and the Remote Spooling and Communications Subsystem (RSCS). Together they form a general purpose tool for the delivery of the computing resources of the IBM System/ 370 machines to a wide variety of people and computers. ...is the operating system used to provide information transfer among machines linked with communications facilities." Details of the design of as a virtual machine subsystem are described in the IBM Systems Journal. From a technical point of view, differed from ARPANET in that it was a point-to-point "store and forward" network, as such it was more like UUCP. Unlike ARPANET, it did not require dedicated Interface Message Processor or continuous network connections. Messages and files were transmitted in their entirety from one server to the next until reaching their destination | https://en.wikipedia.org/wiki?curid=33090200 | 128,431 |
Nadcap (formerly NADCAP, the National Aerospace and Defense Contractors Accreditation Program) is a global cooperative accreditation program for aerospace engineering, defense and related industries. The program is administered by the Performance Review Institute (PRI). was established in 1990 by SAE International. Nadcap's membership consists of "prime contractors" who coordinate with aerospace accredited suppliers to develop industry-wide audit criteria for special processes and products. Through PRI, provides independent certification of manufacturing processes for the industry. PRI has its headquarters in Warrendale, Pennsylvania with branch offices for located in London, Beijing, and Nagoya. The program provides accreditation for special processes in the aerospace and defense industry. These include: PRI schedules an audit and assigns an industry approved auditor who will conduct the audit using an industry agreed checklist. At the end of the audit, any non-conformity issues will be raised through a non-conformance report. PRI will administer and close out the non-conformance reports with the Supplier. Upon completion PRI will present the audit pack to a 'special process Task Group’ made up of members from industry who will review it and vote on its acceptability for approval. The subscribers include: meetings are held several times a year in different locations worldwide. For example, the 2017 meetings were held in New Orleans, LA, USA in February, Berlin (Germany) in June; and Pittsburgh (Pennsylvania) | https://en.wikipedia.org/wiki?curid=3758415 | 197,992 |
Low-power broadcasting The acronym 'LPAM' is not a legal term in the United States and is only used in this article as a (conventional) abbreviation. Unlike LPFM stations, which have legal and regulatory status, FCC rules do not define "LPAM" nor issue licenses for low-power AM transmission. LPAM is only an acronym applied to licensed low-power AM operations and to Part 15 transmissions as well. Any "low power AM" in FCC licensing for stations in the United States is the requirement for higher-power licensed AM stations to reduce their transmit power at nighttime or post-sunset / pre-sunrise as part of their FCC broadcast authorization. There is a category "Class D" for AM broadcast licenses, which limited stations to daytime-only transmission before regulations changed in the 1980s. Many, but not all, Class D stations have been granted authority to broadcast at night with enough power to be heard within a few miles of their transmitters. Other LPAM operations are known as Travelers' Information Stations (TIS), sometimes also called highway advisory radio (HAR). Authorized under FCC Part 90.242, these are stations licensed to local transportation departments or other governmental or quasi-governmental agencies to provide bulletins to motorists regarding traffic conditions. These are often near highways and airports, and occasionally other tourism attractions such as national parks. Some are used by chemical and nuclear facilities for emergency evacuation information systems, others by public safety entities for mobile operations | https://en.wikipedia.org/wiki?curid=272479 | 227,319 |
Hypersonic wind tunnel A hypersonic wind tunnel is designed to generate a hypersonic flow field in the working section, thus simulating the typical flow features of this flow regime - including compression shocks and pronounced boundary layer effects, entropy layer and viscous interaction zones and most importantly high total temperatures of the flow. The speed of these tunnels vary from Mach 5 to 15. The power requirement of a wind tunnel increases with the cross section, the flow density and is directly proportional to the third power of the test velocity. Hence installation of a continuous, closed circuit wind tunnel remains a costly affair. The first continuous Mach 7-10 wind tunnel with 1x1 m test section was planned at Kochel am See, Germany during WW II and finally put into operation as 'Tunnel A' in the late 1950s at AEDC Tullahoma, TN, USA for an installed power of 57 MW. In view of these high facility demands, also intermittently operated experimental facilities like blow-down wind tunnels are designed and installed to simulate the hypersonic flow. A hypersonic wind tunnel comprises in flow direction the main components: heater/cooler arrangements, dryer, convergent/divergent nozzle, test section, second throat and diffuser. A blow-down wind tunnel has a low vacuum reservoir at the back end, while a continuously operated, closed circuit wind tunnel has a high power compressor installation instead. Since the temperature drops with the expanding flow, the air inside the test section has the chance of becoming liquefied | https://en.wikipedia.org/wiki?curid=3677421 | 74,968 |
Tree automaton An rejecting example run is Intuivitvely, this corresponds to the term (,) not being well-typed. Using the same colorization as above, this example shows how tree automata generalize ordinary string automata. The finite deterministic string automaton shown in the picture accepts all strings of binary digits that denote a multiple of 3. Using the notions from Deterministic finite automaton#Formal definition, it is defined by: In the tree automaton setting, the input alphabet is changed such that the symbols and are both unary, and a nullary symbol, say is used for tree leaves. For example, the binary string "" in the string automaton setting corresponds to the term "((()))" in the tree automaton setting; this way, strings can be generalized to trees, or terms. The top-down finite tree automaton accepting the set of all terms corresponding to multiples of 3 in binary string notation is then defined by: For example, the tree "((()))" is accepted by the following tree automaton run: In contrast, the term "(())" leads to following non-accepting automaton run: Since there are no other initial states than to start an automaton run with, the term "(())" is not accepted by the tree automaton. For comparison purposes, the table gives in column (A) and (D) a (right) regular (string) grammar, and a regular tree grammar, respectively, each accepting the same language as its automaton counterpart | https://en.wikipedia.org/wiki?curid=98748 | 137,200 |
Layoff Layoffs in the public sector have put limitations on the growth rate of the private sector, inevitably burdening the entire flow of markets. The risk of being laid off varies depending on the workplace and country a person is working in. Unemployment compensation in any country or workplace typically has two main factors. The first factor of unemployment compensation depends on the distribution of unemployment benefits in a workplace outlined in an employee handbook. The second factor is the risk of inequality being conditioned upon the political regime type in the country an employee is working in. For example, in Canada, Dorion (1995) states that white-collar workers who have been made redundant receive higher re-employment wages than those in blue-collar occupations, as their jobs are regarded as being of a higher status than those of blue collar workers, whereas in France, Margolis (1999, 2002) finds that workers who have been laid off have smaller unemployment periods and higher re-employment earnings in comparison with other unemployed people. The amount of compensation will usually depend on what level the employee holds in the company. Packages may also vary if the employee is laid off, or voluntarily quits in the face of a layoff (VRIF). The method of separation may have an effect on a former employee's ability to collect whatever form of unemployment compensation might be available in their jurisdiction. In many U.S | https://en.wikipedia.org/wiki?curid=507285 | 483,752 |
Forensic engineering The worst kind of defect to occur after launch is a safety-critical defect, a defect that can endanger life or limb. Their discovery usually leads to a product recall or even complete withdrawal of the product from the market. Product defects often follow the bathtub curve, with high initial failures, a lower rate during regular life, followed by another rise due to wear-out. National standards, such as those of ASTM and the British Standards Institute, and International Standards can help the designer in increasing product integrity. There are many examples of forensic methods used to investigate accidents and disasters, one of the earliest in the modern period being the fall of the Dee bridge at Chester, England. It was built using cast iron girders, each of which was made of three very large castings dovetailed together. Each girder was strengthened by wrought iron bars along the length. It was finished in September 1846, and opened for local traffic after approval by the first Railway Inspector, General Charles Pasley. However, on 24 May 1847, a local train to Ruabon fell through the bridge. The accident resulted in five deaths (three passengers, the train guard, and the locomotive fireman) and nine serious injuries. The bridge had been designed by Robert Stephenson, and he was accused of negligence by a local inquest. Although strong in compression, cast iron was known to be brittle in tension or bending | https://en.wikipedia.org/wiki?curid=69817 | 433,347 |
Projects.co.id is an Indonesian freelance and digital goods marketplace which allows project owners and employers to meet potential freelancers. Founded in 2014, provides a platform for job hunter and digital product seller in the e-commerce platform in a variety of categories. The Website is operated under PT Panonpoe Media, early development began in 2013 with Priyatna as its founder and Wiro Hardy joined in 2014 as the co-founder. is a self-funded website project and officially launched on 10 November 2014. It has over 10,000 registered users as of May 2015. The website launched new features in 2015, namely Services feature to offer freelance service in a fixed price, Hire Me feature to directly hire worker without bid auction process and Ask Owner that allow worker to make a straight contact with their potential employer. uses the terms "Project Owner" to call user who want to post a job or a project, accept the bid and its worker. The freelancer, is called as "Worker", can select the project, raise a bid and promote themselves. In the Products and Services features, "Seller" can offers their digital goods to the "Buyer". claimed as the first marketplace that combines a freelance marketplace with digital products e-commerce. Any digital product in form of files may be sold, such as electronic book, graphic design, software, game and website templates. The website also provides a link affiliate program that allows their user receives commission for every project transaction of registered user | https://en.wikipedia.org/wiki?curid=49208513 | 403,740 |
Karl Vorbrodt Karl Vorbrodt, or Carl, (1865, Wabern - 1932, Morcote) was a Swiss entomologist who specialised in Lepidoptera and microlepidoptera). published fauna studies, revisions and descriptions of new species in "Mitteilungen der Schweizerischen Entomologischen Gesellschaft". Together with Johann Müller-Rutz he wrote "Die Schmetterlinge der Schweiz" (Butterflies of Switzerland) Bern K.J. Wyss, 1911-1914. His collection of Palearctic Lepidoptera is in the Natural History Museum of Bern. | https://en.wikipedia.org/wiki?curid=59442895 | 9,709 |
Mobile telephony is the provision of telephone services to phones which may move around freely rather than stay fixed in one location. Telephony is supposed to specifically point to a voice-only service or connection, though sometimes the line may blur. Mobile phones connect to a terrestrial cellular network of base stations (cell sites), whereas satellite phones connect to orbiting satellites. Both networks are interconnected to the public switched telephone network (PSTN) to allow any phone in the world to be dialed. In 2010 there were estimated to be five billion mobile cellular subscriptions in the world. According to internal memos, American Telephone & Telegraph discussed developing a wireless phone in 1915, but were afraid that deployment of the technology could undermine its monopoly on wired service in the U.S. Public mobile phone systems were first introduced in the years after the Second World War and made use of technology developed before and during the conflict. The first system opened in St Louis, Missouri, USA in 1946 whilst other countries followed in the succeeding decades. The UK introduced its 'System 1' manual radiotelephone service as the South Lancashire Radiophone Service in 1958. Calls were made via an operator using handsets identical to ordinary phone handsets. The phone itself was a large box located in the boot (trunk) of the vehicle containing valves and other early electronic components | https://en.wikipedia.org/wiki?curid=1145887 | 293,543 |
J. F. Kennedy Memorial, Birmingham The text gives an incorrect date of 1960, the year he was elected, for the start of his presidency, when he was actually president from January 1961. This inaccuracy was also present in the original creation. The original mosaic had wording at either side. The wording on the right said (all in upper case): <poem> There are no white or coloured signs on the grave- yards of battle </poem> The recreated mosaic has different words. On the left (again, all in upper case): <poem> In tribute to John F Kennedy President of the United States 1960-3 </poem> and to the right: <poem> A man may die nations may rise and fall but an idea lives on </poem> | https://en.wikipedia.org/wiki?curid=38321272 | 329,075 |
Headroom (audio signal processing) In digital and analog audio, headroom refers to the amount by which the signal-handling capabilities of an audio system exceed a designated nominal level. Headroom can be thought of as a safety zone allowing transient audio peaks to exceed the nominal level without damaging the system or the audio signal, e.g., via clipping. Standards bodies differ in their recommendations for nominal level and headroom. In digital audio, headroom is defined as the amount by which digital full scale (FS) exceeds the nominal level in decibels (dB). The European Broadcasting Union (EBU) specifies several nominal levels and resulting headroom for different applications. In analog audio, headroom can mean low-level signal capabilities as well as the amount of extra power reserve available within the amplifiers that drive the loudspeakers. Alignment level is an anchor point 9 dB below the nominal level, a reference level that exists throughout the system or broadcast chain, though it may imply different voltage levels at different points in the analog chain. Typically, nominal (not alignment) level is 0 dB, corresponding to an analog sine wave of voltage of 1.23 volts RMS (+4 dBu or 3.47 volts peak to peak). In the digital realm, alignment level is −18 dBFS. | https://en.wikipedia.org/wiki?curid=1635317 | 401,131 |
Clinical trial Among his major ideas, was the importance of randomization – the random assignment of individuals to different groups for the experiment; replication – to reduce uncertainty, measurements should be repeated and experiments replicated to identify sources of variation; blocking – to arrange experimental units into groups of units that are similar to each other, and thus reducing irrelevant sources of variation; use of factorial experiments – efficient at evaluating the effects and possible interactions of several independent factors. The British Medical Research Council officially recognized the importance of clinical trials from the 1930s. The Council established the "Therapeutic Trials Committee" to advise and assist in the arrangement of properly controlled clinical trials on new products that seem likely on experimental grounds to have value in the treatment of disease. The first randomised curative trial was carried out at the MRC Tuberculosis Research Unit by Sir Geoffrey Marshall (1887–1982). The trial, carried out between 1946–1947, aimed to test the efficacy of the chemical streptomycin for curing pulmonary tuberculosis. The trial was both double-blind and placebo-controlled. The methodology of clinical trials was further developed by Sir Austin Bradford Hill, who had been involved in the streptomycin trials. From the 1920s, Hill applied statistics to medicine, attending the lectures of renowned mathematician Karl Pearson, among others | https://en.wikipedia.org/wiki?curid=241717 | 25,512 |
Roman technology The caldarium, unlike the tepidarium, was extremely humid and hot. Temperatures in the caldarium could reach 40 degrees Celsius (104 degrees Fahrenheit). Many contained steam baths and a cold-water fountain known as the labrum. The last room was the frigidarium or cold room, which offered a cold bath for cooling off after the caldarium. The Romans also had flush toilets. The containment of heat in the rooms was important in the operation of the baths, as to avoid patrons from catching colds. To prevent doors from being left open, the door posts were installed at an inclined angle so that the doors would automatically swing shut. Another technique of heat efficiency was the use of wooden benches over stone, as wood conducts away less heat. The Romans primarily built roads for their military. Their economic importance was probably also significant, although wagon traffic was often banned from the roads to preserve their military value. In total, more than of roads were constructed, of which were stone-paved. Way stations providing refreshments were maintained by the government at regular intervals along the roads. A separate system of changing stations for official and private couriers was also maintained. This allowed a dispatch to travel a maximum of in 24 hours by using a relay of horses. The roads were constructed by digging a pit along the length of the intended course, often to bedrock. The pit was first filled with rocks, gravel or sand and then a layer of concrete | https://en.wikipedia.org/wiki?curid=14901914 | 290,501 |
Craig Reynolds (computer graphics) Craig W. Reynolds (born March 15, 1953), is an artificial life and computer graphics expert, who created the Boids artificial life simulation in 1986. Reynolds worked on the film "Tron" (1982) as a scene programmer, and on "Batman Returns" (1992) as part of the video image crew. Reynolds won the 1998 Academy Scientific and Technical Award in recognition of "his pioneering contributions to the development of three-dimensional computer animation for motion picture production." He is the author of the "OpenSteer" library. | https://en.wikipedia.org/wiki?curid=449965 | 278,152 |
Hydration energy (also hydration enthalpy) is the amount of energy released when one mole of ions undergo hydration. is one component in the quantitative analysis of solvation. It is a particular special case of water. The value of hydration energies is one of the most challenging aspects of structural prediction. Upon dissolving a salt in water, the cations and anions interact with the positive and negative dipoles of the water. The trade-off of these interactions vs those within the crystalline solid comprises the hydration energy. is correlated with ionic radius of cations and anions, as done by Wendell Latimer. If the hydration energy is greater than the lattice energy, then the enthalpy of solution is negative (heat is released), otherwise it is positive (heat is absorbed). The hydration energy should not be confused with solvation energy, which is the change in Gibb's free energy (not enthalpy) as solute in the gaseous state is dissolved. If the solvation energy is positive, then the solvation process is endergonic; otherwise, it is exergonic. For instance, water warms when treated with CaCl (anhydrous calcium chloride) as a consequence of the large heat of hydration. However, the hexahydrate, CaCl·6HO cools the water upon dissolution. The latter happens because the hydration energy does not completely overcome the lattice energy, and the remainder has to be taken from the water in order to compensate the energy loss. The hydration energies of the gaseous Li, Na, and Cs are respectively 520, 405, and 265 kJ/mol. | https://en.wikipedia.org/wiki?curid=36853181 | 73,241 |
Tire Science and Technology is a quarterly peer-reviewed scientific journal that publishes original research and reviews on experimental, analytical, and computational aspects of tires. Since 1978, the Tire Society has published the journal. The current editor-in-chief is Michael Kaliske (Dresden University of Technology). Topics of interest to journal readers include, but are not limited to: adhesion, aerospace, aging, agriculture, automotive, composite materials, constitutive modeling, contact mechanics, cord mechanics, curing, design theories, durability, elastomers, finite element analysis, force and moment behavior, groove wander, heat build up, hydroplaning, impact, manufacturing, mechanics, military, noise, pavement, performance evaluation, racing, rolling resistance, snow and ice, soil, standing waves, stiffness, strength, traction, vehicle dynamics, vibration, wear. The journal was founded in 1973 and was originally published by a committee of the American Society for Testing and Materials until 1977. | https://en.wikipedia.org/wiki?curid=4853266 | 215,474 |
Indoor air quality The type of ozone being regulated is ground-level ozone that is within the breathing range of most building occupants Atmospheric particulate matter, also known as particulates, can be found indoors and can affect the health of occupants. Authorities have established standards for the maximum concentration of particulates to ensure indoor air quality. In 2015, experimental studies reported the detection of significant episodic (situational) cognitive impairment from impurities in the air breathed by test subjects who were not informed about changes in the air quality. Researchers at the Harvard University and SUNY Upstate Medical University and Syracuse University measured the cognitive performance of 24 participants in three different controlled laboratory atmospheres that simulated those found in "conventional" and "green" buildings, as well as green buildings with enhanced ventilation. Performance was evaluated objectively using the widely used Strategic Management Simulation software simulation tool, which is a well-validated assessment test for executive decision-making in an unconstrained situation allowing initiative and improvisation. Significant deficits were observed in the performance scores achieved in increasing concentrations of either VOCs or carbon dioxide, while keeping other factors constant. The highest impurity levels reached are not uncommon in some classroom or office environments | https://en.wikipedia.org/wiki?curid=219736 | 500,214 |
Dana S 110 The Dana/Spicer Model S110 is an automotive axle manufactured by the Dana Holding Corporation and the Eaton Corporation. Eaton manufactures the carrier and Dana manufactures the rest of the axle. The S110 model follows a newer nomenclature for Dana axles. The "S" meaning: single rear axle. The first "1" representing gear reduction type, the second representing the head assembly series and the last "0" representing the design level. The Dana S110 is used in Class 4 and Class 5 applications. Dodge, Ford and General Motors use this axle as well as various other companies. The Dana S110 is a full floating, drop-out axle. Dana S110 axles are a step up in overall strength compared to the Dana 80. Ford started using this axle in 2005 model F-450 and F-550 trucks. Replacing the Dana 80 in some class 4 trucks, and the Dana S 135 in the rest of the trucks. Dodge started using the Dana S110 in their 2008 model 4500 and 5500 trucks. Although this axle is designed for medium-duty, commercial-trucks, Ford did put the S110 in 2008-2010 & 2015-2016 F-450 Pick up trucks. The Dana S110 has a GAWR up to 14,706 lbs but is frequently, de-rated by vehicle manufacturer for safety and tire reasons. This axle is not used in 1 Ton trucks (Class 3). OEM ratios range from 3.07:1 to 6.50:1 "Model year 2011 - 2014 Ford F-450 pick up trucks, Class 3, use the Dana 80 axle" | https://en.wikipedia.org/wiki?curid=23984381 | 423,170 |
Sine quadrant However, it does help to have another person write down the scale readings as they are taken if a single operator is not able to do such because of environmental conditions, the single operator not having the capability to sufficiently hold the device stable, retaining the optical alignment, with just one hand. Making altitude (elevation) measurements of the Sun being simple and direct, requiring the user to aligning the image of the Sun through the front pinhole (aperture), centered onto the rear back plate which operates more like a mask and not a viewing pass hole for sighting the Sun with the naked eye. Much in the same manner as performing eyepiece projection with a telescope, one fashioned with a front and rear aperture (font lens and rear eyepiece) along with a projection screen behind the eyepiece, or more rudimentary, the projecting of the Sun's image upon a small screen plate such as that done with a mariner's back staff. The rear, or second aperture (pass hole) having the function of working as a blacken attenuator so that any reflecting, annulus shaped sunlight off the metal aperture is not too bright, the Sun's image (light) passing through the second hole and similar in task though void of a fixed image plane, to that of an iris (diaphragm) in a camera lens to reduce the light intensity | https://en.wikipedia.org/wiki?curid=20747100 | 261,988 |
Synchronous coefficient of drag alteration Consider a particle under a force field that has a velocity parallel to the field direction and a speed proportional to the square of the magnitude of the electric field (any other non-linearity can be employed): The effective mobility of the particle (the relationship between small changes in drift velocity formula_14 with respect to small changes in electric field formula_15) can be expressed in Cartesian coordinates as: Combining (5), (6) and (7) we get: Further consider the field E is applied in a plane and it rotates counter-clockwise at angular frequency formula_20, such that the field components are: Substituting (10) and (11) in (8) and (9) and simplifying using trigonometric identities results in a sum of constant terms, sine and cosine, at angular frequency formula_23. The next calculations will be performed such that only the cosine terms at angular frequency formula_23 will yield non-zero net drift velocity - therefore we need only evaluate these terms, which will be abbreviated formula_2 and formula_26 | https://en.wikipedia.org/wiki?curid=50177303 | 180,839 |
Optical tweezers Commonly, two traps are generated by splitting the laser beam into two orthogonally polarized beams. Optical tweezing operations with more than two traps can be realized either by time-sharing a single laser beam among several optical tweezers, or by diffractively splitting the beam into multiple traps. With acousto-optic deflectors or galvanometer-driven mirrors, a single laser beam can be shared among hundreds of optical tweezers in the focal plane, or else spread into an extended one-dimensional trap. Specially designed diffractive optical elements can divide a single input beam into hundreds of continuously illuminated traps in arbitrary three-dimensional configurations. The trap-forming hologram also can specify the mode structure of each trap individually, thereby creating arrays of optical vortices, optical tweezers, and holographic line traps, for example. When implemented with a spatial light modulator, such holographic optical traps also can move objects in three dimensions. Advanced forms of holographic optical traps with arbitrary spatial profiles, where smoothness of the intensity and the phase are controlled, find applications in many areas of science, from micromanipulation to ultracold atoms. The standard fiber optical trap relies on the same principle as the optical trapping, but with the Gaussian laser beam delivered through an Optical fiber | https://en.wikipedia.org/wiki?curid=299901 | 67,599 |
Real-time computer graphics If using a right-handed coordinate system (which is considered standard), the observer looks in the direction of the negative z-axis with the y-axis pointing upwards and the x-axis pointing to the right. Projection is a transformation used to represent a 3D model in a 2D space. The two main types of projection are orthographic projection (also called parallel) and perspective projection. The main characteristic of orthographic projection is that parallel lines remain parallel after the transformation. Perspective projection utilizes the concept that if the distance between the observer and model increases, the model appears smaller than before. Essentially, perspective projection mimics human sight. Clipping is the process of removing primitives that are outside of the view box in order to facilitate the rasterizer stage. Once those primitives are removed, the primitives that remain will be drawn into new triangles that reach the next stage. The purpose of screen mapping is to find out the coordinates of the primitives during the clipping stage. The rasterizer stage applies color and turns the graphic elements into pixels or picture elements. Computer animation has been around since the 1940s and 1950s, but it was not until the 1970s and 1980s that 3D techniques were implemented. The first step towards 3D graphics was taken in 1972 by Edwin Catmull and Fred Parke. Their implementation featured a computer-generated hand and face that was created using wire-frame imagery | https://en.wikipedia.org/wiki?curid=1564205 | 109,644 |
Positive-real function However, a similar more general condition, not restricted to rational functions had earlier been considered by Cauer, and some authors ascribe the term "positive-real" to this type of condition, while others consider it to be a generalization of the basic definition. The condition was first proposed by Wilhelm Cauer (1926) who determined that it was a necessary condition. Otto Brune (1931) coined the term positive-real for the condition and proved that it was both necessary and sufficient for realisability. A couple of generalizations are sometimes made, with intention of characterizing the immittance functions of a wider class of passive linear electrical networks. The impedance "Z"("s") of a network consisting of an infinite number of components (such as a semi-infinite ladder), need not be a rational function of "s", and in particular may have branch points on the negative real "s"-axis. To accommodate such functions in the definition of PR, it is therefore necessary to relax the condition that the function be real for all real "s", and only require this when "s" is positive. Thus, a possibly irrational function "Z"("s") is PR if and only if Some authors start from this more general definition, and then particularize it to the rational case. Linear electrical networks with more than one port may be described by impedance or admittance matrices. So by extending the definition of PR to matrix-valued functions, linear multi-port networks which are passive may be distinguished from those that are not | https://en.wikipedia.org/wiki?curid=23437839 | 131,478 |
Corrugated galvanised iron The traditional shape of corrugated material is the round wavy style, but different dies form a variety of shapes and sizes. Industrial buildings are often build with and covered by trapezoidal sheet metal. Many materials today undergo the corrugation process. The most common materials for corrugated iron are ferrous alloys (e.g. stainless steels), aluminium and copper. Regular ferrous alloys are the most common due to price and availability. Common sizes of corrugated material can range from a very thin 30 gauge () to a relatively thick 6 gauge (). Thicker or thinner gauges may also be produced. Other materials such as plastic and fibreglass are also given the corrugated look. Many applications are available for these products including using them with metal sheets to allow light to penetrate below. The corrugations are described in terms of pitch (the distance between two crests) and depth (the height from the top of a crest to the bottom of a trough). It is important for the pitch and depth to be quite uniform, in order for the sheets to be easily stackable for transport, and to overlap neatly when joining two sheets. Pitches have ranged from 25 mm (1 inch) to 125 mm (5 inches). It was once common for CGI used for vertical walls to have a shorter pitch and depth than roofing CGI. This shorter pitched material was sometimes called "rippled" instead of "corrugated". However nowadays, nearly all CGI produced has the same pitch of 3 inches (76 mm) | https://en.wikipedia.org/wiki?curid=875035 | 319,313 |
Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this process. The starting point for modern botanical nomenclature is Linnaeus' "Species Plantarum" of 1753. is governed by the "International Code of Nomenclature for algae, fungi, and plants" ("ICN"), which replaces the "International Code of Botanical Nomenclature" ("ICBN"). Fossil plants are also covered by the code of nomenclature. Within the limits set by that code there is another set of rules, the "International Code of Nomenclature for Cultivated Plants (ICNCP)" which applies to plant cultivars that have been deliberately altered or selected by humans (see cultigen). has a long history, going back beyond the period when Latin was the scientific language throughout Europe, to Theophrastus (c. 370–287 BC), Dioscorides (c. 40 – 90 AD) and other Greek writers. Many of these works have come down to us in Latin translations. The principal Latin writer on botany was Pliny the Elder (23–79 AD). From Mediaeval times, Latin became the universal scientific language (lingua franca) in Europe. Most written plant knowledge was the property of monks, particularly Benedictine, and the purpose of those early herbals was primarily medicinal rather than plant science "per se". It would require the invention of the printing press (1450) to make such information more widely available | https://en.wikipedia.org/wiki?curid=2697067 | 173,702 |
Creative destruction A few years later, in the "Grundrisse", Marx was writing of "the violent destruction of capital not by relations external to it, but rather as a condition of its self-preservation". In other words, he establishes a necessary link between the generative or creative forces of production in capitalism and the destruction of capital value as one of the key ways in which capitalism attempts to overcome its internal contradictions: These contradictions lead to explosions, cataclysms, crises, in which ... momentaneous suspension of labour and annihilation of a great portion of capital ... violently lead it back to the point where it is enabled [to go on] fully employing its productive powers without committing suicide. In the "Theories of Surplus Value" ("Volume IV" of "Das Kapital", 1863), Marx refines this theory to distinguish between scenarios where the destruction of (commodity) values affects either use values or exchange values or both together. The destruction of exchange value combined with the preservation of use value presents clear opportunities for new capital investment and hence for the repetition of the production-devaluation cycle: the destruction of capital through crises means the depreciation of values which prevents them from later renewing their reproduction process as capital on the same scale. This is the ruinous effect of the fall in the prices of commodities. It does not cause the destruction of any use-values. What one loses, the other gains | https://en.wikipedia.org/wiki?curid=99656 | 269,308 |
Human-robot collaboration Shared Cooperative Activity defines certain prerequisites for an activity to be considered shared and cooperative: mutual responsiveness, commitment to the joint activity and commitment to mutual support. An example case to illustrate these concepts would be a collaborative activity where agents are moving a table out the door, mutual responsiveness ensures that movements of the agents are synchronized; a commitment to the joint activity reassures each team member that the other will not at some point drop his side; and a commitment to mutual support deals with possible breakdowns due to one team member’s inability to perform part of the plan. Joint Intention Theory proposes that for joint action to emerge, team members must communicate to maintain a set of shared beliefs and to coordinate their actions towards the shared plan. In collaborative work, agents should be able to count on the commitment of other members, therefore each agent should inform the others when they reach the conclusion that a goal is achievable, impossible, or irrelevant. The approaches to human-robot collaboration include human emulation (HE) and human complementary (HC) approaches. Although these approaches have differences, there are research efforts to develop a unified approach stemming from potential convergences such as Collaborative Control. The human emulation approach aims to enable computers to act like humans or have human-like abilities in order to collaborate with humans | https://en.wikipedia.org/wiki?curid=60084964 | 199,688 |
Bayesian experimental design of which the latter can be evaluated without the need for evaluating individual posterior PDFs formula_19 for all possible observations formula_4. It is worth noting that the first term on the second equation line will not depend on the design formula_6, as long as the observational uncertainty doesn't. On the other hand, the integral of formula_22 in the first form is constant for all formula_6, so if the goal is to choose the design with the highest utility, the term need not be computed at all. Several authors have considered numerical techniques for evaluating and optimizing this criterion, e.g. and . Note that the expected information gain being exactly the mutual information between the parameter "θ" and the observation "y". The Kelly criterion also describes such a utility function for a gambler seeking to maximize profit, which is used in gambling and information theory; Kelly's situation is identical to the foregoing, with the side information, or "private wire" taking the place of the experiment. | https://en.wikipedia.org/wiki?curid=1706860 | 196,199 |
Lift-off (microtechnology) Finally, lifting off a material is an option if there is no access to an etching tool with the appropriate gases. There are 3 major problems with lift-off: If the ears remain on the surface, the risk remains that these ears will go through different layers put on top of the wafer and they might cause unwanted connections. Lift-off process is used mostly to create metallic interconnections. <br> There are several types of lift-off processes, and what can be achieved depends highly on the actual process being used. Very fine structures have been used using EBL, for instance. The lift-off process can also involve multiple layers of different types of resist. This can for instance be used to create shapes that will prevent side walls of the resist being covered in the metal deposition stage. | https://en.wikipedia.org/wiki?curid=16793276 | 401,976 |
Reboiler Some fluids are temperature sensitive such as those subject to polymerization by contact with high temperature heat transfer tube walls. High liquid recirculation rates are used to reduce tube wall temperatures, thereby reducing polymerization on the tube and associated fouling. | https://en.wikipedia.org/wiki?curid=6977357 | 55,719 |
Ylide Typically, triphenylphosphine is allowed to react with an alkyl halide in a mechanism analogous to that of an S2 reaction. This quaternization forms an alkyltriphenylphosphonium salt, which can be isolated or treated in situ with a strong base (in this case, butyl lithium) to form the ylide. Due to the S2 mechanism, a less sterically hindered alkyl halide reacts more favorably with triphenylphosphine than an alkyl halide with significant steric hindrance (such as tert-butyl bromide). Because of this, there will typically be one synthetic route in a synthesis involving such compounds that is more favorable than another. Phosphorus ylides are important reagents in organic chemistry, especially in the synthesis of naturally occurring products with biological and pharmacological activities. Much of the interest in the coordination properties of a-keto stabilized phosphorus ylides stems from their coordination versatility due to the presence of different functional groups in their molecular structure. The a-keto stabilized ylides derived from bisphosphines like dppe, dppm, etc., viz., [PhPCHPPh]C(H)C(O)R and [PhPCHCHPPh]C(H)C(O)R (R = Me, Ph or OMe) constitute an important class of hybrid ligands containing both phosphine and ylide functionalities, and can exist in ylidic and enolate forms. These ligands can therefore be engaged in different kinds of bonding with metal ions like palladium and platinum | https://en.wikipedia.org/wiki?curid=511767 | 34,344 |
Intron 6 megabase (Mb) intron, which takes roughly three days to transcribe. On the other extreme, a recent study suggests that the shortest known eukaryotic intron length is 30 base pairs (bp) belonging to the human "MST1L" gene. Splicing of all intron-containing RNA molecules is superficially similar, as described above. However, different types of introns were identified through the examination of intron structure by DNA sequence analysis, together with genetic and biochemical analysis of RNA splicing reactions. At least four distinct classes of introns have been identified: Group III introns are proposed to be a fifth family, but little is known about the biochemical apparatus that mediates their splicing. They appear to be related to group II introns, and possibly to spliceosomal introns. Nuclear pre-mRNA introns (spliceosomal introns) are characterized by specific intron sequences located at the boundaries between introns and exons. These sequences are recognized by spliceosomal RNA molecules when the splicing reactions are initiated. In addition, they contain a branch point, a particular nucleotide sequence near the 3' end of the intron that becomes covalently linked to the 5' end of the intron during the splicing process, generating a branched ("lariat") intron. Apart from these three short conserved elements, nuclear pre-mRNA intron sequences are highly variable. Nuclear pre-mRNA introns are often much longer than their surrounding exons | https://en.wikipedia.org/wiki?curid=15343 | 48,184 |
Extensional viscosity (also known as elongational viscosity) is a viscosity coefficient when applied stress is extensional stress. "Extensional viscosity" can be measured using rheometers that apply "extensional stress". Acoustic rheometer is one example of such devices. where For a Newtonian Fluid, the uniaxial elongational viscosity is three times the shear viscosity which can be derived using the continuity equation for incompressible fluids. | https://en.wikipedia.org/wiki?curid=13860656 | 80,683 |
Sliplining is one of the oldest methods for trenchless rehabilitation of existing pipelines. is used to repair leaks or restore structural stability to an existing pipeline. is completed by installing a smaller, "carrier pipe" into a larger "host pipe", grouting the annular space between the two pipes, and sealing the ends. has been used since the 1940s. The most common material used to slipline an existing pipe is high-density polyethylene (HDPE), but fiberglass-reinforced pipe (FRP) and PVC are also common. can be used to stop infiltration and restore structural integrity to an existing pipe. The most common size is (8"-60"), but sliplining can occur in any size given appropriate access and a new pipe small or large enough to install. There are two methods used to install a slipline: continuous and segmental. Continuous sliplining uses a long continuous pipe, such as HDPE, Fusible PVC, or Welded Steel Pipe, that are connected into continuous pieces of any length prior to installation. The continuous carrier pipe is pulled through the existing host pipe starting at an insertion pit and continuing to a receiving pit. Either the insertion pit, the receiving pit, or both can be manholes or other existing access points if the size and material of the new carrier pipe can maneuver the existing facilities. Segmental sliplining is very similar to continuous sliplining. The difference is primarily based on the pipe material used as the new carrier pipe | https://en.wikipedia.org/wiki?curid=22673291 | 266,917 |
Lexitropsin Lexitropsins are members of a family of semi-synthetic DNA-binding ligands. They are structural analogs of the natural antibiotics netropsin and distamycin. Antibiotics of this group can bind in the minor groove of DNA with different sequence-selectivity. Lexitropsins form a complexes with DNA with stoichiometry 1:1 and 2:1. Based on the 2:1 complexes were obtained ligands with high sequence-selectivity. | https://en.wikipedia.org/wiki?curid=22275501 | 141,387 |
Mechanisms of mindfulness meditation The insula is responsible for awareness to stimuli and the thickness of its gray matter correlates to the accuracy and detection of the stimuli by the nervous system. Qualitative evidence suggests that mindfulness meditation impacts body awareness, however this component is not well characterized. Emotions can be regulated cognitively or behaviorally. Cognitive regulation (in terms of mindfulness meditation) means having control over giving attention to a particular stimuli or by changing the response to that stimuli. The cognitive change is achieved through reappraisal (interpreting the stimulus in a more positive manner) and extinction (reversing the response to the stimulus). Behavioral regulation refers to inhibiting the expression of certain behaviors in response to a stimulus. Research suggests two main mechanisms for how mindfulness meditation influences the emotional response to a stimulus. Lateral prefrontal cortex (lPFC) is important for selective attention while ventral prefrontal cortex (vPFC) is involved in inhibiting a response. As noted before, the anterior cingulate cortex (ACC) has been noted for maintaining attention to a stimulus. The amygdala is responsible for generating emotions. Mindfulness meditation is believed to be able to regulate negative thoughts and decrease emotional reactivity through these regions of the brain. Emotion regulation deficits have been noted in disorders such as borderline personality disorder and depression | https://en.wikipedia.org/wiki?curid=41119232 | 156,988 |
Onyx Pharmaceuticals Onyx announced on June 30, 2013, that it rejected the unsolicited proposal from Amgen. The Onyx board has authorized its financial adviser to contact potential suitors. The acquisition was formally announced on 25 August 2013. In July 2014 the company announced the phase III failure of a Sorafenib-Capecitabine combination trial. The drug combination failed to increase progression free survival of patients with advanced breast cancer. | https://en.wikipedia.org/wiki?curid=33293566 | 466,952 |
Acid attack High incidence of acid assaults have been reported in some African countries, including Nigeria, Uganda, and South Africa. Unlike occurrences in South Asia, acid attacks in these countries show less gender discrimination. In Uganda, 57% of acid assault victims were female and 43% were male. A study focusing on chemical burns in Nigeria revealed a reversal in findings—60% of the acid attack patients were male while 40% were female. In both nations, younger individuals were more likely to suffer from an acid attack: the average age in the Nigeria study was 20.6 years, while Ugandan analysis shows 59% of survivors were 19–34 years of age. Motivation for acid assault in these African countries is similar to that of Cambodia. Relationship conflicts caused 35% of acid attacks in Uganda in 1985–2011, followed by property conflicts at 8%, and business conflicts at 5%. Disaggregated data was not available in the Nigeria study, but they reported that 71% of acid assaults resulted from an argument with either a jilted lover, family member, or business partner. As with the other nations, researchers believe these statistics to be under-representative of the actual scope and magnitude of acid attacks in African nations. In August 2013, two Jewish women volunteer teachers—Katie Gee and Kirstie Trup from the UK—were injured by an acid attack by men on a moped near Stone Town in Tanzania. A few cases also occurred in Ethiopia and Nigeria | https://en.wikipedia.org/wiki?curid=30862640 | 19,021 |
Abstract data type In computer science, an abstract data type (ADT) is a mathematical model for data types. An abstract data type is defined by its behavior (semantics) from the point of view of a "user", of the data, specifically in terms of possible values, possible operations on data of this type, and the behavior of these operations. This mathematical model contrasts with data structures, which are concrete representations of data, and are the point of view of an implementer, not a user. Formally, an ADT may be defined as a "class of objects whose logical behavior is defined by a set of values and a set of operations"; this is analogous to an algebraic structure in mathematics. What is meant by "behavior" varies by author, with the two main types of formal specifications for behavior being "axiomatic (algebraic) specification" and an "abstract model;" these correspond to axiomatic semantics and operational semantics of an abstract machine, respectively. Some authors also include the computational complexity ("cost"), both in terms of time (for computing operations) and space (for representing values). In practice many common data types are not ADTs, as the abstraction is not perfect, and users must be aware of issues like arithmetic overflow that are due to the representation. For example, integers are often stored as fixed-width values (32-bit or 64-bit binary numbers), and thus experience integer overflow if the maximum value is exceeded | https://en.wikipedia.org/wiki?curid=2349 | 134,586 |
Carrier aggregation is a technique used in wireless communication to increase the data rate per user, whereby multiple frequency blocks (called "component carriers") are assigned to the same user. The maximum possible data rate per user is increased the more frequency blocks are assigned to a user. The sum data rate of a cell is increased as well because of a better resource utilization. In addition "load balancing" is possible with carrier aggregation. Channel selection schemes for CA systems taking into account the optimal values for the training length and power, the number of the probed sub-channels and the feedback threshold such that the sum rate is also important for optimal achievable capacity. Depending on the positions of the component carriers three cases of carrier aggregation are distinguished: There is no difference between these three cases from a baseband perspective. However, the complexity from an RF point of view is increased in the case inter-band carrier aggregation. The channel bandwidth for UMTS/HSPA+ is about 3.8 MHz with a carrier spacing of 5 MHz. is also called Dual Cell in the context of UMTS/HSPA+. Through carrier aggregation (part of the UMTS extension HSPA+) two downlink carriers may be assigned to one user since Release 8. Release 10 supports four-carrier aggregation and eight-carrier-aggregation is supported since Release 11. 3GPP standardized carrier aggregation for HSPA+ for the uplink for up to two component carriers since Release 9. LTE supports since its first release channel bandwidths of 1 | https://en.wikipedia.org/wiki?curid=59185446 | 130,269 |
History of the steel industry (1850–1970) The discovery of Iron Knob and Iron Monarch near the western shore of the Spencer Gulf in South Australia combined with the development by the BHP metallurgist, A. D. Carmichael, of a technique for 'separating zinc sulphides from the accompanying earth and rock' led BHP 'to implement the startlingly simple and cheap process for liberating vast amounts of valuable metals out of sulphide ores, including huge heaps of tailings and slimes up to' high. The Ruhr Valley provided an excellent location for the German iron and steel industry because of the availability of raw materials, coal, transport, a skilled labor force, nearby markets, and an entrepreneurial spirit that led to the creation of many firms, often in close conjunction with coal mines. By 1850 the Ruhr had 50 iron works with 2,813 full-time employees. The first modern furnace was built in 1849. The creation of the German Empire in 1871 gave further impetus to rapid growth, as Germany started to catch up with Britain. From 1880 to World War I, the industry of the Ruhr area consisted of numerous enterprises, each working on a separate level of production. Mixed enterprises could unite all levels of production through vertical integration, thus lowering production costs. Technological progress brought new advantages as well. These developments set the stage for the creation of combined business concerns. The leading firm was Friedrich Krupp AG run by the Krupp family | https://en.wikipedia.org/wiki?curid=8911974 | 47,600 |
Industrial symbiosis Even within the PV plant itself a secondary chemical recycling plant can reduce environmental impact while improving economic performance for the group of manufacturing facilities. In DCM Shriram consolidated limited (Kota unit) produces caustic soda, calcium carbide, cement and PVC resins. Chlorine and hydrogen are obtained as by-products from caustic soda production, while calcium carbide produced is partly sold and partly is treated with water to form slurry(aqueous solution of calcium hydroxide) and ethylene. The chlorine and ethylene produced are utilised to form PVC compounds, while the slurry is consumed for cement production by wet process. Hydrochloric acid is prepared by direct synthesis where the pure chlorine gas can be combined with hydrogen to produce hydrogen chloride in the presence of UV light. | https://en.wikipedia.org/wiki?curid=12562201 | 348,242 |
Rupert Sheldrake The group observed that Sheldrake's observed patterns could easily arise if a dog were simply to do very little for a while, before visiting a window with increasing frequency the longer that its owner was absent, and that such behaviour would make sense for a dog awaiting its owner's return. Under this behaviour, the final measurement period, ending with the owner's return, would always contain the most time spent at the window. Sheldrake argued that the actual data in his own and in Wiseman's tests did not bear this out, and that the dog went to wait at the window sooner when his owner was returning from a short absence, and later after a long absence, with no tendency for Jaytee to go to the window early in the way that he did for shorter absences. Reviewing the book, Susan Blackmore criticised Sheldrake for comparing the 12 tests of random duration – which were all less than an hour in duration – to the initial tests where the dog may have been responding to patterns in the owner's journeys. Blackmore interpreted the results of the randomised tests as starting with a period where the dog "settles down and does not bother to go to the window," and then showing that the longer the owner was away, the more the dog went to look. Sheldrake's "The Sense of Being Stared At" explores telepathy, precognition, and the "psychic staring effect." It reported on an experiment Sheldrake conducted where blindfolded subjects guessed whether persons were staring at them or at another target | https://en.wikipedia.org/wiki?curid=142395 | 193,000 |
Surface-mount technology Each method has its advantages and disadvantages. With infrared reflow, the board designer must lay the board out so that short components don't fall into the shadows of tall components. Component location is less restricted if the designer knows that vapor phase reflow or convection soldering will be used in production. Following reflow soldering, certain irregular or heat-sensitive components may be installed and soldered by hand, or in large-scale automation, by focused infrared beam (FIB) or localized convection equipment. If the circuit board is double-sided then this printing, placement, reflow process may be repeated using either solder paste or glue to hold the components in place. If a wave soldering process is used, then the parts must be glued to the board prior to processing to prevent them from floating off when the solder paste holding them in place is melted. After soldering, the boards may be washed to remove flux residues and any stray solder balls that could short out closely spaced component leads. Rosin flux is removed with fluorocarbon solvents, high flash point hydrocarbon solvents, or low flash solvents e.g. limonene (derived from orange peels) which require extra rinsing or drying cycles. Water-soluble fluxes are removed with deionized water and detergent, followed by an air blast to quickly remove residual water | https://en.wikipedia.org/wiki?curid=232333 | 409,730 |
Chafery A chafery is a variety of hearth used in ironmaking for reheating a bloom of iron, in the course of its being drawn out into a bar of wrought iron. The equivalent term for a bloomery was string hearth, except in 17th century Cumbria, where the terminology was that of the finery forge. A finery forge for the Walloon process would typically have one chafery to work two fineries (but sometimes one or three fineries). Chaferies were also used in the potting and stamping forges of the industrial revolution. | https://en.wikipedia.org/wiki?curid=17638686 | 43,539 |
Georg Ludwig Engelhard Krebs These specimens had been collected from Baviaans River, Tembuland, and the Tarka and Orange Rivers. His brother Georg arrived in Cape Town in May 1834 and was granted a medical licence, joining the other members of the family at "Lichtenstein" in July. Much work went into building up the farm after it had been through the Sixth Kaffir War of 1834/5. Krebs' letters about the war survive. Georg set up a practice in Graaff-Reinet, later becoming District Surgeon. Krebs' partner Leopold Scmidt died in July 1836 and Krebs disposed of all his Grahamstown interests, but continued dispensing from the farm. For a long time Ludwig Krebs had been thinking about an expedition north of the Orange and Vaal Rivers. Accordingly, accompanied by his nephew Carl Klemper, he left his farm in March 1838 with four wagons. His route was through the present-day Aliwal North, Jammersberg near Wepener, Thaba Nchu, north-east toward Clocolan, Mpharane near Ficksburg, and northwards to the Makwassie area. He crossed the Sand River near the present Senekal and followed it westward, and then northwards to the Vals River. He went west again crossing the Vaal River, probably at Kommando Drift, and then northwards to the Makwassie highlands where he collected for several weeks. His return leg followed a more westerly route, and he arrived at 'Lichtenstein' toward the end of December 1838 | https://en.wikipedia.org/wiki?curid=40371530 | 982 |
Asymmetric induction Improving Felkin–Anh selectivity for organometal additions to aldehydes can be achieved by using organo-aluminum nucleophiles instead of the corresponding Grignard or organolithium nucleophiles. Claude Spino and co-workers have demonstrated significant stereoselectivity improvements upon switching from vinylgrignard to vinylalane reagents with a number of chiral aldehydes. Addition of achiral allylmetals to aldehydes forms a chiral alcohol, the stereochemical outcome of this reaction is determined by the chirality of the α-carbon on the aldehyde substrate (Figure "Substrate control: addition of achiral allylmetals to α-chiral aldehydes"). The allylmetal reagents used include boron, tin and titanium. Cram’s rule explains the stereoselectivity by considering the transition state depicted in figure 3. In the transition state the oxygen lone pair is able to interact with the boron centre whilst the allyl group is able to add to the carbon end of the carbonyl group. The steric demand of this transition state is minimized by the α-carbon configuration holding the largest group away from (trans to) the congested carbonyl group and the allylmetal group approaching past the smallest group on the α-carbon centre. In the example below (Figure "An example of substrate controlled addition of achiral allyl-boron to α-chiral aldehyde"), (R)-2-methylbutanal (1) reacts with the allylboron reagent (2) with two possible diastereomers of which the (R, R)-isomer is the major product | https://en.wikipedia.org/wiki?curid=4879260 | 91,813 |
Lock and key A lock is a mechanical or electronic fastening device that is released by a physical object (such as a key, keycard, fingerprint, RFID card, security token, coin, etc.), by supplying secret information (such as a number or letter permutation or password), or by a combination thereof or only being able to be opened from one side such as a door chain. A key is a device that is used to operate a lock (such as to lock or unlock it). A typical key is a small piece of metal consisting of two parts: the "bit" or "blade", which slides into the keyway of the lock and distinguishes between different keys, and the "bow", which is left protruding so that torque can be applied by the user. In its simplest implementation, a key operates one lock or set of locks that are keyed alike, a lock/key system where each similarly keyed lock requires the same, unique key. The key serves as a security token for access to the locked area; only persons having the correct key can open the lock and gain access. In more complex mechanical lock/key systems, two different keys, one of which is known as the master key, serve to open the lock. Common metals include brass, plated brass, nickel silver, and steel. The earliest known lock and key device was discovered in the ruins of Nineveh, the capital of ancient Assyria. Locks such as this were later developed into the Egyptian wooden pin lock, which consisted of a bolt, door fixture or attachment, and key | https://en.wikipedia.org/wiki?curid=525465 | 430,353 |
Lithium–silicon battery Prototypical lithium-silicon batteries lose most of their capacity in as little as 10 charge-discharge cycles. A solution to the capacity and stability issues posed by the significant volume expansion upon lithiation is critical to the success of silicon anodes. Because the volume expansion and contraction properties of nanoparticles differ greatly from the bulk, silicon nanostructures have been investigated as a potential solution. While they have a higher percentage of surface atoms than bulk silicon particles, the increased reactivity may be controlled by encasement, coatings, or other methods that limit surface—electrolyte contact. One method identified by researchers has used silicon nanowires on a conductive substrate for an anode, and found that the nanowire morphology creates direct current pathways to help increase power density and decreases disruption from volume change. However, the large volume change of the nanowires can still pose a fading problem. Other studies examined the potential of silicon nanoparticles. Anodes that use silicon nanoparticles may overcome the price and scale barriers of nanowire batteries, while offering more mechanical stability over cycling compared to other silicon electrodes. Typically, these anodes add carbon as a conductive additive and a binder for increased mechanical stability | https://en.wikipedia.org/wiki?curid=47270052 | 231,794 |
Köprü Dam The is a gravity dam on the Göksu, the main tributary of the Seyhan River about northwest of Kozan in Adana Province, Turkey. Its primary purpose is hydroelectric power generation. Construction began in 2009 and was complete in 2012. On 24 February 2012, the dam's diversion tunnel seal broke while the dam was impounding the river for the first time. This resulted in of water flooding the downstream area of the dam. The accident and subsequent flood killed 10 workers. Downstream communities received proper warning and no one was killed. | https://en.wikipedia.org/wiki?curid=34883064 | 325,676 |
Bolaamphiphile CAN 150:475745 AN 2008:763292 Chen, Senlin; Song, Bo; Wang, Zhiqiang; Zhang, Xi. Self-Organization of Bearing Biphenyl Mesogen and Aspartic-Acid Headgroups. Journal of Physical Chemistry C (2008), 112(9), 3308-3313. CODEN: JPCCCK . CAN 148:372219 AN 2008:176360 Feng Qiu, Chengkang Tang, Yongzhu Chen Amyloid-like aggregation of designer bolaamphiphilic peptides: Effect of hydrophobic section and hydrophilic heads. Journal of peptide science. (2017) DOI: 10.1002/psc.3062 | https://en.wikipedia.org/wiki?curid=13415486 | 12,191 |
History of video games While about two million handsets were sold, the product line wasn't seen as a success and was withdrawn from Nokia's lineup. Meanwhile, many game developers had noticed that more advanced phones had color screens and enough memory and processing power to do reasonable gaming. Mobile phone gaming revenues passed 1 billion dollars in 2003, and passed 5 billion dollars in 2007, accounting for a quarter of all videogaming software revenues. More advanced phones came to the market such as the N-Series smartphone by Nokia in 2005 and the iPhone by Apple in 2007 which strongly added to the appeal of mobile phone gaming. In 2008 Nokia didn't revise the N-Gage brand, but published a software library of games to its top-end phones. At Apple's App Store in 2008, more than half of all applications sold were iPhone games. Due to the debut of app stores created by Apple and Google, plus the low-cost retail price of downloadable phone apps, games available on smartphones increasingly rival the video game console market. Among the most successful mobile games of this period is "Angry Birds", which, released in 2009, reached 2 million downloads within one year. Nintendo announced their intentions for developing more games and content for mobile devices in the early 2010s, while Sega company is also dedicating development resources toward creating more mobile games | https://en.wikipedia.org/wiki?curid=32401 | 209,455 |
Waybill A waybill (UIC) is a document issued by a carrier giving details and instructions relating to the shipment of a consignment of goods. Typically it will show the names of the consignor and consignee, the point of origin of the consignment, its destination, and route. Most freight forwarders and trucking companies use an in-house waybill called a house bill. These typically contain "conditions of contract of carriage" terms on the back of the form that cover limits to liability and other terms and conditions. A waybill is similar to that of a courier's receipt, which contains the details of the consignor and the consignee and the point of origin and the destination. Most airlines use a different form called an air waybill which lists additional items such as airport of destination, flight number, and time. The UK Carriage of Goods by Sea Act 1992 s.1(1) applies to: ... whether in paper or electronic form s.1(5). Under s.1(3) of the Act, a sea waybill is: "any document which is not a bill of lading but is such a receipt for goods as contains a contract for the carriage of goods by sea; and identifies the person to whom delivery of the goods is to be made by the carrier in accordance with that contract". s.2 continues: "...a person who becomes the person who (without being an original party to the contract of carriage) is the person to whom delivery of the goods to which a sea waybill relates is to be made by the carrier in accordance with that contract .. | https://en.wikipedia.org/wiki?curid=610419 | 484,521 |
Stokes flow Lamb's general solution arises from the fact that the pressure formula_31 satisfies the Laplace equation, and can be expanded in a series of solid spherical harmonics in spherical coordinates. As a result, the solution to the Stokes equations can be written: where formula_33 and formula_34 are solid spherical harmonics of order formula_35: and the formula_37 are the associated Legendre polynomials. The Lamb's solution can be used to describe the motion of fluid either inside or outside a sphere. For example, it can be used to describe the motion of fluid around a spherical particle with prescribed surface flow, a so-called squirmer, or to describe the flow inside a spherical drop of fluid. For interior flows, the terms with formula_38 are dropped, while for exterior flows the terms with formula_39 are dropped (often the convention formula_40 is assumed for exterior flows to avoid indexing by negative numbers). The drag resistance to a moving sphere, also known as Stokes' solution is here summarised. Given a sphere of radius formula_41, travelling at velocity formula_42, in a Stokes fluid with dynamic viscosity formula_43, the drag force formula_44 is given by: The Stokes solution dissipates less energy than any other solenoidal vector field with the same boundary velocities: this is known as the Helmholtz minimum dissipation theorem. The Lorentz reciprocal theorem states a relationship between two Stokes flows in the same region. Consider fluid filled region formula_46 bounded by surface formula_47 | https://en.wikipedia.org/wiki?curid=2047298 | 422,610 |
Pre-determined overhead rate Instead of using a pre-determined rate based on estimates, why not base the overhead rate on the actual total manufacturing overhead cost and the actual total amount of the activity base incurred on a monthly, quarterly, or annual basis? If an actual rate is computed monthly or quarterly, seasonal factors in overhead costs or in the activity base can produce fluctuations in the overhead rate. For example, the costs of heating and cooling a factory in Illinois will be highest in the winter and summer months and lowest in the spring and fall. If the overhead rate is recomputed at the end of each month or each quarter based on actual costs and activity, the overhead rate would go up in the winter and summer and down in the spring and fall. As a result, two identical jobs, one completed in the winter and one completed in the spring, would be assigned different manufacturing overhead costs. Many managers believe that such fluctuations in product costs serve no useful purpose. To avoid such fluctuations, actual overhead rates could be computed on an annual or less-frequent basis. However, if the overhead rate is computed annually based on the actual costs and activity for the year, the manufacturing overhead assigned to any particular job would not be known until the end of the year. For example, the cost of Job 2B47 at Yost Precision Machining would not be known until the end of the year, even though the job will be completed and shipped to the customer in March | https://en.wikipedia.org/wiki?curid=2270140 | 482,523 |
Francium Initial measurements show very good agreement between experimental values and calculations based on quantum theory. The research project using this production method relocated to TRIUMF in 2012, where over 10 francium atoms have been held at a time, including large amounts of Fr in addition to Fr and Fr. Other synthesis methods include bombarding radium with neutrons, and bombarding thorium with protons, deuterons, or helium ions. Fr can also be isolated from samples of its parent Ac, the francium being milked via elution with NHCl–CrO from an actinium-containing cation exchanger and purified by passing the solution through a silicon dioxide compound loaded with barium sulfate. In 1996, the Stony Brook group trapped 3000 atoms in their MOT, which was enough for a video camera to capture the light given off by the atoms as they fluoresce. has not been synthesized in amounts large enough to weigh. | https://en.wikipedia.org/wiki?curid=10821 | 40,439 |
Vibration fatigue methods find use wherever the structure experiences loading, that is caused by a random process. These can be the forces that bumps on the road extort on the car chassis, the wind blowing on the wind turbine, waves hitting an offshore construction or a marine vessel. Such loads are first characterized statistically, by measurement and analysis. The data is then used in the product design process. The computational effectiveness of vibration-fatigue methods in contrast to the classical approach, enables their use in combination with FEM software packages, to evaluate fatigue after the loading is known and the dynamic analysis has been performed. Use of the vibration-fatigue methods is well-suited, as structural analysis is studied in the frequency-domain. Common practice in the automotive industry is the use of accelerated vibration tests. During the test, a part or a product is exposed to vibration, that are in correlation with those expected during the service-life of the product. To shorten the testing time, the amplitudes are amplified. The excitation spectra used are broad-band and can be evaluated most effectively using vibration-fatigue methods. | https://en.wikipedia.org/wiki?curid=36945036 | 333,942 |
Dynamometer For example, if an engine dyno shows that a particular engine achieves of torque, and a chassis dynamo shows only , one would know that the drivetrain losses are nominal. Dynamometers are typically very expensive pieces of equipment, and so are normally used only in certain fields that rely on them for a particular purpose. A 'brake' dynamometer applies variable load on the prime mover (PM) and measures the PM's ability to move or hold the RPM as related to the "braking force" applied. It is usually connected to a computer that records applied braking torque and calculates engine power output based on information from a "load cell" or "strain gauge" and a speed sensor. An 'inertia' dynamometer provides a fixed inertial mass load, calculates the power required to accelerate that fixed and known mass, and uses a computer to record RPM and acceleration rate to calculate torque. The engine is generally tested from somewhat above idle to its maximum RPM and the output is measured and plotted on a graph. A 'motoring' dynamometer provides the features of a brake dyno system, but in addition, can "power" (usually with an AC or DC motor) the PM and allow testing of very small power outputs (for example, duplicating speeds and loads that are experienced when operating a vehicle traveling downhill or during on/off throttle operations) | https://en.wikipedia.org/wiki?curid=908654 | 247,868 |
History of books Literacy was in general on the rise, with a near universal literacy rate in Western Europe, Australia and the United States of America by 1890, with the inequality between men and women's literacy starting to equalize by 1900. The printing press became increasingly mechanized. Early designs for metal and steam-powered printing presses were introduced in the early 19th century by inventors like Friederich Koenig and Charles Stanhope. However they became widely adopted by the 1830s, particularly by newspapers such as the London Times. Around the same time a revolution was triggered in paper production by Henry Fourdrinier and Thomas Gilpin, whose new paper making machines output very wide continuous rolls of paper. The only bottleneck to book production was the time-consuming process of composition. This was eventually solved by Ottmar Mergenthaler and Tolbert Lanston who produced the Linotype and Monotype machines respectively. With these barriers removed book production exploded. Great strides began in the realm of publishing as authors began to enjoy early forms of Copyright protection. The Statute of Anne was passed in 1710, establishing basic rights for the author's intellectual property. This was superseded by the Copyright Act of 1814 which transferred sole rights to a print work for twenty eight years after publication. This was extended in 1842 to the author's lifetime plus seven years, or forty two years after first publication | https://en.wikipedia.org/wiki?curid=1591936 | 260,494 |
Atmospheric chemistry An especially important driver for this is the links between chemistry and climate such as the effects of changing climate on the recovery of the ozone hole and vice versa but also interaction of the composition of the atmosphere with the oceans and terrestrial ecosystems. Observations, lab measurements, and modeling are the three central elements in atmospheric chemistry. Progress in atmospheric chemistry is often driven by the interactions between these components and they form an integrated whole. For example, observations may tell us that more of a chemical compound exists than previously thought possible. This will stimulate new modelling and laboratory studies which will increase our scientific understanding to a point where the observations can be explained. Observations of atmospheric chemistry are essential to our understanding. Routine observations of chemical composition tell us about changes in atmospheric composition over time. One important example of this is the Keeling Curve - a series of measurements from 1958 to today which show a steady rise in of the concentration of carbon dioxide (see also ongoing measurements of atmospheric CO). Observations of atmospheric chemistry are made in observatories such as that on Mauna Loa and on mobile platforms such as aircraft (e.g. the UK's Facility for Airborne Atmospheric Measurements), ships and balloons | https://en.wikipedia.org/wiki?curid=706999 | 24,663 |
Pipeline transport Effective protocols to minimize exposure to petrochemical vapours are well-established, and oil spilled from the pipeline would be unlikely to reach the aquifer unless incomplete remediation were followed by the introduction of another carrier (e.g. a series of torrential downpours). The introduction of benzene and other volatile organic compounds (collectively BTEX) to the subterranean environment compounds the threat posed by a pipeline leak. Particularly if followed by rain, a pipeline breach would result in BTEX dissolution and equilibration of benzene in water, followed by percolation of the admixture into the aquifer. Benzene can cause many health problems and is carcinogenic with EPA Maximum Contaminant Level (MCL) set at 5 μg/L for potable water. Although it is not well studied, single benzene exposure events have been linked to acute carcinogenesis. Additionally, the exposure of livestock, mainly cattle, to benzene has been shown to cause many health issues, such as neurotoxicity, fetal damage and fatal poisoning. The entire surface of an above-ground pipeline can be directly examined for material breach. Pooled petroleum is unambiguous, readily spotted, and indicates the location of required repairs. Because the effectiveness of remote inspection is limited by the cost of monitoring equipment, gaps between sensors, and data that requires interpretation, small leaks in buried pipe can sometimes go undetected Pipeline developers do not always prioritize effective surveillance against leaks | https://en.wikipedia.org/wiki?curid=51111 | 323,968 |
Gas exchange The reaction is therefore catalyzed by carbonic anhydrase, an enzyme inside the red blood cells. The reaction can go in either direction depending on the prevailing partial pressure of carbon dioxide. A small amount of carbon dioxide is carried on the protein portion of the hemoglobin molecules as carbamino groups. The total concentration of carbon dioxide (in the form of bicarbonate ions, dissolved CO, and carbamino groups) in arterial blood (i.e. after it has equilibrated with the alveolar air) is about 26 mM (or 58 ml/100 ml), compared to the concentration of oxygen in saturated arterial blood of about 9 mM (or 20 ml/100 ml blood). The dissolved oxygen content in fresh water is approximately 8–10 milliliters per liter compared to that of air which is 210 milliliters per liter. Water is 800 times more dense than air and 100 times more viscous. Therefore, oxygen has a diffusion rate in air 10,000 times greater than in water. The use of sac-like lungs to remove oxygen from water would therefore not be efficient enough to sustain life. Rather than using lungs, gaseous exchange takes place across the surface of highly vascularized gills. Gills are specialised organs containing filaments, which further divide into lamellae. The lamellae contain capillaries that provide a large surface area and short diffusion distances, as their walls are extremely thin. Gill rakers are found within the exchange system in order to filter out food, and keep the gills clean | https://en.wikipedia.org/wiki?curid=379303 | 174,264 |
Zintl phase In chemistry, a is the product of a reaction between a group 1 (alkali metal) or group 2 (alkaline earth) and any post-transition metal or metalloid (i.e. from group 13, 14, 15 or 16). It is named after the German chemist Eduard Zintl who investigated them in the 1930s, with the term "Zintl Phases" first used by Laves in 1941. Zintl phases are a subgroup of brittle, high-melting intermetallic compounds which are diamagnetic or exhibit temperature-independent paramagnetism, and are poor conductors or semiconductors. Zintl noted that there was an atomic volume contraction when these compounds were formed and realised this could indicate cation formation. He suggested that the structures of Zintl phases were ionic, where there was complete electron transfer from the more electropositive metal. The structure of the anion (nowadays called the Zintl ion) should then be considered on the basis of the resulting electronic state. These ideas were further developed to become the Zintl rule or Zintl Klemm concept, where the polyanion structure should be similar to an isoelectronic element. Zintl phases are polyanionic compounds. Their structure can be understood by a formal electron transfer from the electropositive metal to the more electronegative element. Thus, the valence-electron concentration (VEC) of the element is increased and it formally moves to the right in the periodic system of elements. Generally, the formed anion does not reach an electron-octet | https://en.wikipedia.org/wiki?curid=9912921 | 55,113 |
Secure signature creation device The server will then compare the user’s credentials against its database. If the information matches, the CAS will respond that the user has been authenticated. eIDAS has provided a tiered approach to determining the legal implications of electronic signatures. A signature that has been created with a secure signature creation device is considered to have the strongest probative value. A document or message that has been signed with such a device is non-reputable, meaning the signatory cannot deny they are responsible for the creation of the signature. Regulation (EU) No 910/2014 (eIDAS) evolved from Directive 1999/93/EC, the Electronic Signatures Directive. The intent of the directive was to make EU Member States responsible for creating legislation that would allow for the creation of the European Union’s electronic signing system. The eIDAS Regulation required all Member States to follow its specifications for electronic signatures by its effective date of 1 July 2016. | https://en.wikipedia.org/wiki?curid=52313606 | 256,020 |
Analog signal processing A plot in the time domain shows the amplitude of the signal with respect to time. A plot in the frequency domain shows either the phase shift or magnitude of a signal at each frequency that it exists at. These can be found by taking the Fourier transform of a time signal and are plotted similarly to a bode plot. While any signal can be used in analog signal processing, there are many types of signals that are used very frequently. Sinusoids are the building block of analog signal processing. All real world signals can be represented as an infinite sum of sinusoidal functions via a Fourier series. A sinusoidal function can be represented in terms of an exponential by the application of Euler's Formula. An impulse (Dirac delta function) is defined as a signal that has an infinite magnitude and an infinitesimally narrow width with an area under it of one, centered at zero. An impulse can be represented as an infinite sum of sinusoids that includes all possible frequencies. It is not, in reality, possible to generate such a signal, but it can be sufficiently approximated with a large amplitude, narrow pulse, to produce the theoretical impulse response in a network to a high degree of accuracy. The symbol for an impulse is δ(t). If an impulse is used as an input to a system, the output is known as the impulse response | https://en.wikipedia.org/wiki?curid=405746 | 377,092 |
Charcot–Leyden crystals are microscopic crystals composed of eosinophil protein galectin-10 found in people who have allergic diseases such as asthma or parasitic infections such as parasitic pneumonia or ascariasis. are composed of an eosinophilic lysophospholipase binding protein called Galectin -10. They vary in size and may be as large as 50 µm in length. are slender and pointed at both ends, consisting of a pair of hexagonal pyramids joined at their bases. Normally colorless, they are stained purplish-red by trichrome. They are indicative of a disease involving eosinophilic inflammation or proliferation, such as is found in allergic reactions (asthma, bronchitis, allergic rhinitis and rhinosinusitis) and parasitic infections such as "Entamoeba histolytica", "Necator americanus", and "Ancylostoma duodenale". are often seen pathologically in patients with bronchial asthma. Friedrich Albert von Zenker was the first to notice these crystals, doing so in 1851, after which they were described jointly by Jean-Martin Charcot and Charles-Philippe Robin in 1853, then in 1872 by Ernst Viktor von Leyden. | https://en.wikipedia.org/wiki?curid=3194204 | 148,283 |
Charles Coulson Charles Alfred Coulson (13 December 1910 – 7 January 1974) was a British applied mathematician, theoretical chemist and religious author. His major scientific work was as a pioneer of the application of the quantum theory of valency to problems of molecular structure, dynamics and reactivity. He was also a Methodist lay preacher, served on the World Council of Churches from 1962 to 1968, and was chairman of Oxfam from 1965 to 1971. The parents of and his younger twin brother John Metcalfe Coulson were educators who hailed from the Midlands. The twins were born when their father, Alfred, was principal of Dudley Technical College and superintendent of the Methodist Sunday School, and their mother Annie Sincere Hancock was Headmistress of Tipton Elementary School, close by. Dudley is about 25 miles west of Birmingham and 10 miles east of Wolverhampton. Coulson's parents maintained a religious Methodist home. When the Coulson brothers were 10, their father was appointed Superintendent of Technical Colleges for the South-West of England, and the family moved to Bristol. Charles attended the XIV Preparatory School. When he was 13, he was awarded a scholarship to Clifton College, in Bristol that placed a strong emphasis on science and mathematics. His hobbies and recreations included stamp collecting, cricket, tennis and chess. Coulson's academic success at Clifton earned him an Entrance Scholarship in Mathematics to Trinity College, Cambridge in 1928 | https://en.wikipedia.org/wiki?curid=228184 | 25,107 |
Telephone hybrid When lines are conferenced and the gain around the loop of the multiple hybrids is greater than unity, feedback "singing" will be audible. If the leakage is very high, operators will not be able to control the relative levels of the host audio and the caller since the console telephone fader will affect both signals. The digital signal processing technology used in modern hybrids addresses the isolation requirement and implements ancillary functions. ISDN and VoIP telco connections theoretically have no need for hybrids. However, calls that have ISDN or VoIP on one end usually terminate to an analog line at the other, and so there is a significant source of echo from both the telco hybrid on the line card and the phone itself. Acoustic coupling, when the microphone picks up the output of the earpiece, is another potential source of echo. Electrical pickup between analog circuits (crosstalk) is yet another. Even low echo levels can be audible when there is a long delay, as is usually the case with VoIP. Telephone hybrids intended for studio applications are usually rack-mount units that have RJ-style connectors for the telephone line and either balanced analog or AES3 audio inputs/outputs on XLR connectors for the studio equipment connection. One, two, or more hybrids might be packaged within a unit. There are variations to accommodate either POTS, ISDN, or VoIP telephone lines | https://en.wikipedia.org/wiki?curid=949960 | 217,276 |
Defense strategy (computing) The strategy is based on the assumption that finding and repairing the damage is more complicated than the restoration of the system. Examples of this strategy include using system restoration, keeping backup files, and using a backup computer. This is a supporting strategy for information system monitoring. This strategy consumes considerable resources, and the scope is known. It can be fully successful in its part. Limiting of actions made by a robot is a strategy performing security measures to limit a robot's (software bot) actions. The strategy is based on the assumption that a robot can take more actions, or create damage that a human cannot create. Examples of this strategy include using anti-spam techniques, using CAPTCHA and other human presence detection techniques, and using DDS-based defense (protection from Denial-of-service attack). This is a supporting strategy for boundary protection and information system monitoring. It is a time and resource-consuming strategy, and the scope is determined by the designer. This strategy cannot be fully successful on its own. Active defense is a strategy performing security measures attacking the potential intruders. The strategy is based on the assumption that a potential intruder under attack has fewer abilities. Examples of this strategy include creating and using lists of trusted networks, devices, and applications, blocking untrusted addresses, and vendor management. This is a supporting strategy for boundary protection and information system monitoring | https://en.wikipedia.org/wiki?curid=62436026 | 115,276 |
Aerospace manufacturer Following are Texas, Georgia, Arizona and Colorado. In the European Union, aerospace companies such as Airbus, Safran, BAE Systems, Thales, Dassault, Saab AB, Terma A/S, Patria Plc and Leonardo are participants in the global aerospace industry and research effort. In Russia, large aerospace companies like Oboronprom and the United Aircraft Corporation (encompassing Mikoyan, Sukhoi, Ilyushin, Tupolev, Yakovlev, and Irkut, which includes Beriev) are among the major global players in this industry. In the US, the Department of Defense and NASA are the two biggest consumers of aerospace technology and products. The Bureau of Labor Statistics of the United States reported that the aerospace industry employed 444,000 wage and salary jobs in 2004, many of which were in Washington and California, this marked a steep decline from the peak years during the Reagan Administration when total employment exceeded 1,000,000 aerospace industry workers. During that period of recovery a special program to restore U.S. competitiveness across all U.S. industries, Project Socrates, contributed to employment growth as the U.S. aerospace industry captured 72 percent of world aerospace market. By 1999 U.S. share of the world market fell to 52 percent. Important locations of the civil aerospace industry worldwide include Seattle, Wichita, Kansas, Dayton, Ohio and St | https://en.wikipedia.org/wiki?curid=79610 | 470,152 |
Dispersal vector Hummingbirds spread pollen on their beaks, and fungal spores may stick to the bottom of birds’ feet. Water birds may also help to disperse aquatic invertebrates, specifically branchiopods, ostracods, and bryozoans. This includes all of the dispersal caused by ants, including seed dispersal and the dispersal of leaf matter from trees. Similarly to birds, dispersal by mammals allows for long distance dispersal, especially via carnivores. The act of carnivores eating primary dispersal vectors (herbivores) can lead to long distance dispersal and connection between different populations of the same species because of large predator ranges in comparison to smaller herbivore ranges. Mammals have been shown to act as dispersal vectors for seeds, spores, and parasites. Just as in ornithocory, ingestion by herbivores acts as a dispersal vector for seeds, and gut passage increases the rate of germination. Marsupials, primates, rodents, bats, and some species in the suborder Feliformia (Cape grey mongooses and Cape genets) have all been identified as pollinators. Non-flying mammals have been identified as acting as pollinators in Australia, Africa, South and Central America. Some plants may have traits that coevolved to utilize mammals as dispersal vectors, such as being extremely pungent in odor, nocturnal nectar production, and robust flowers that can handle rough feeders. The pollen of some plants can be found stuck to the fur of mammals as well as accidentally ingested when nectar is consumed | https://en.wikipedia.org/wiki?curid=23665572 | 171,497 |
Hwaseong Fortress The north-east pavilion is known as Dongbuk Gangnu and nicknamed Banghwasuryujeong. It sits above Yongyeon, a pond surrounded by a small garden. It was originally intended to be the second battle command post, though its scenic location made it a place favoured instead for feasts. Hwahongmun, otherwise known as Buksumun, is the gate under which the Suwoncheon flows on entering the area encompassed by Hwaseong and exited through Namsumun. The gate has the obvious function of being a bridge, but also housed cannons for defensive purposes. The Suwoncheon was widened at this point and the gate has seven arches through which it passes. Bukdong-GunTower sits between Janganmun and Hwahongmun. This tower controls the North-East outskirts of the Fortress, and protects Hwahongmun. It was completed on September 23, 1794. Not to be confused with 동북포루, the East-North SentryPost. Bukdong Chi, the north-eastern turret, sits immediately to the east of the north-eastern gate guard platform. Bukdong Jeokdae is a platform immediately to the east of Janganmun. It housed a cannon to protect the gate and its "ongseong". Janganmun, known locally as Bungmun (North Gate), is the largest such gate in Korea. Some believe this is intentional, as it is through this gate that visitors from Seoul will have entered Suwon and this would be in keeping with King Jeongjo's original desire to move the capital of the country to Suwon. Janganmun's stone base is capped with a two-storey wooden pavilion | https://en.wikipedia.org/wiki?curid=3879882 | 201,933 |
Major soil deposits of India There are seven soil deposits in India. These soils are formed by the sediments brought down by the rivers. They are also rich in chemical ingredients. The rivers deposit very fine particles of soil in different parts of India. Mountain soils are found in the valleys and hill slopes of the Himalayas at altitudes of 2100 m to 3000 m. These soils are least studied and often the vegetation cover helps in their classification.The carbon nitrogen ratio is very wide. They are silty loam to loam in texture and dark brown in colour. These soils are found in Thar desert in the Indian state of Rajasthan. This soil is formed from arid condition with practically negligible rainfall. This type of soil is highly pervious and have a low density. It requires densification to increase its bearing capacity and shearing strength. Commonly recognised plants that grow in these soils are cacti. These soils are also called as regur soils. These soils are mainly found in Central India and the Deccan Plateau. The soil is suitable for growing cottons. It is believed that the climatic conditions along with the parent rock material are the important factors for the formation of black soil. This type of soil is typically of the Deccan trap region spread over Northwest Deccan plateau and is made from lava flows. They cover the plateaus of Maharashtra, Saurashtra, Malwa, Madhya Pradesh, Chhattisgarh and extend in South-East direction along Godavari and Krishna valleys. These soils contain essential clay minerals as montmorillonite | https://en.wikipedia.org/wiki?curid=43068147 | 436,102 |
Counterion condensation The counterion condensation phenomenon is commonly described by Manning's theory (Manning 1969), which assumes that counterions can condense onto polyions until the charged density between neighboring monomer charges along the polyion chain is reduced below a certain critical value. In the model the real polyion chain is replaced by an idealized line charge, where the polyion is represented by a uniformly charged thread of zero radius, infinite length and finite charge density, and the condensed counterion layer is assumed to be in physical equilibrium with the ionic atmosphere surrounding the polyion. The uncondensed mobile ions in the ionic atmosphere are treated within the Debye–Hückel (DH) approximation. The phenomenon of counterion condensation now takes place when the dimensionless Coulomb coupling strength where formula_2 represents the Bjerrum length and formula_3 the distance between neighboring charged monomers. In this case the Coulomb interactions dominate over the thermal interactions and counterion condensation is favored. For many standard polyelectrolytes, this phenomenon is relevant, since the distance between neighboring monomer charges typically ranges between 2 and 3 Å and formula_4 7 Å in water. The Manning theory states that the fraction of "condensed" counter ions is formula_5, where "condensed" means that the counter ions are located within the Manning radius formula_6 | https://en.wikipedia.org/wiki?curid=27657824 | 71,735 |
Wiring diagram For example, a surface ceiling light is shown by one symbol, a recessed ceiling light has a different symbol, and a surface fluorescent light has another symbol. Each type of switch has a different symbol and so do the various outlets. There are symbols that show the location of smoke detectors, the doorbell chime, and thermostat. On large projects symbols may be numbered to show, for example, the panel board and circuit to which the device connects, and also to identify which of several types of fixture are to be installed at that location. A set of wiring diagrams may be required by the electrical inspection authority to approve connection of the residence to the public electrical supply system. Wiring diagrams will also include panel schedules for circuit breaker panelboards, and riser diagrams for special services such as fire alarm or closed circuit television or other special services. | https://en.wikipedia.org/wiki?curid=17772449 | 369,727 |
Alternative fuel vehicle Honda introduced its fuel cell vehicle in 1999 called the FCX and have since then introduced the second generation FCX Clarity. Limited marketing of the FCX Clarity, based on the 2007 concept model, began in June 2008 in the United States, and it was introduced in Japan in November 2008. The FCX Clarity was available in the U.S. only in Los Angeles Area, where 16 hydrogen filling stations are available, and until July 2009, only 10 drivers have leased the Clarity for US$600 a month. At the 2012 World Hydrogen Energy Conference, Daimler AG, Honda, Hyundai and Toyota all confirmed plans to produce hydrogen fuel cell vehicles for sale by 2015, with some types planned to enter the showroom in 2013. From 2008 to 2014, Honda leased a total of 45 FCX units in the US. A small number of prototype hydrogen cars currently exist, and a significant amount of research is underway to make the technology more viable. The common internal combustion engine, usually fueled with gasoline (petrol) or diesel liquids, can be converted to run on gaseous hydrogen. However, the most efficient use of hydrogen involves the use of fuel cells and electric motors instead of a traditional engine. Hydrogen reacts with oxygen inside the fuel cells, which produces electricity to power the motors. One primary area of research is hydrogen storage, to try to increase the range of hydrogen vehicles while reducing the weight, energy consumption, and complexity of the storage systems. Two primary methods of storage are metal hydrides and compression | https://en.wikipedia.org/wiki?curid=8340209 | 287,367 |
KXTX-TV 55 million to Pappas Telecasting Companies, which had formed a partnership with Mexico City-based broadcaster TV Azteca to launch a Spanish language television network, to be known as Azteca América. Upon that disclosure in its FCC purchase application, CBN founder Pat Robertson included a stipulation in the Pappas sale agreement that required the group to broadcast the station's programming entirely in English until May 31, 2001 with an opt-out clause that could be exercised on December 31, 2000 (Robertson had long endorsed, particularly through his Christian Coalition of America organization, that English should be the official language of the United States), and required Hicks to lease an hour of airtime on KXTX each weekday morning to CBN-produced programming, including "The 700 Club" (a stipulation similar to that which CBN imposed on the cable channel now known as Freeform to its subsequent owners following the sale to IFE). Plans for KXTX under Pappas called for it to serve as the flagship station of Azteca América and base the network's technical operations center at its studios, where the network's programming, promotions and commercial spots would be automatically fed to its affiliates | https://en.wikipedia.org/wiki?curid=2005391 | 412,044 |
Dietary conservatism For example, extended experience with multiple different colours of novel food makes a DC individual more likely to accept an additional novel colour. Conversely, encounters with novel food which is distasteful, increases the strength of the DC response, making the individual extremely averse to novel foods thereafter. Social cues can also be important. If a domestic chick (without direct access to food) observes another individual consuming novel food, then the avoidance of novel food by the observer is reduced. Alternatively, if chicks cannot see the food choice, and their companion is simply a competitor for food, then DC individuals become more DC and only take the familiar food. The strength of expression of DC also depends on the forager’s perceived risk of predation pressure, hunger levels, and perceived availability of food. It is possible that the balance of DC and AC foraging strategies in a population is influenced by the forager’s ecology. For example, DC may be favoured in habitats where prey are relatively cryptic, since it allows the predator to specialise on a single prey type. In this way DC individuals could benefit from the use of a ‘search image’ for that prey type and the accumulation of experience of handling that prey. In addition, where there are many toxic prey types, DC foragers may be favoured as they are less likely to be poisoned if they eat only nontoxic prey, with which they are already familiar | https://en.wikipedia.org/wiki?curid=61351399 | 162,918 |
Occupational safety and health Such talks are often used, especially in the construction industry, by site supervisors, front line managers and owners of small construction firms to prepare and deliver advice on matters of health, safety and the environment and to obtain feedback from the workforce. On April 28 The International Labour Organization celebrates "World Day for Safety and Health" to raise awareness of safety in the workplace. Occurring annually since 2003, each year it focuses on a specific area and bases a campaign around the theme. | https://en.wikipedia.org/wiki?curid=35319154 | 64,377 |
Woman's Club of El Paso The Woman's Club decided to create a permanent building for the club in 1915, raising club dues and appealing to local businesses for donations in order to get funding. The clubhouse was designed by the architect, Otto H. Thorman and construction began in 1916. The building was the first free-standing woman's clubhouse in the state of Texas. The clubhouse was officially opened on November 8, 1916. Members of the Woman's Club were involved in the establishment of Texas's first public school kindergarten. The club, led by one of the Woman's Club presidents, Olga Kohlberg, worked to get a kindergarten established in the first school building in El Paso, Central School, in 1893. Kohlberg also helped establish the first hospital in El Paso, by creating the Ladies' Benevolent Association. Members of the club were also heavily involved in establishing the El Paso Public Library. Mary Irene Stanton, who was the first president of the El Paso Library Association in 1895, was elected the Woman's Club vice-president that same year. Stanton created the first children's library in the United States. By 1913, El Paso had "over thirty women's organizations," though most were social in nature, and contrasted with the "civic and humanitarian objectives" of the Woman's Club. Another president of the club, Eugenia Schuster, helped refugees from the Mexican Revolution in 1916, working with Amigos Listos. The club worked to get safe food and public sanitation laws passed and also worked to protect San Jacinto Plaza | https://en.wikipedia.org/wiki?curid=49633577 | 333,125 |
AquaMaps is a collaborative project with the aim of producing computer-generated (and ultimately, expert reviewed) predicted global distribution maps for marine species on a 0.5 x 0.5 degree grid of the oceans based on data available through online species databases such as FishBase and SeaLifeBase and species occurrence records from OBIS or GBIF and using an environmental envelope model (see niche modelling) in conjunction with expert input. The underlying model represents a modified version of the relative environmental suitability (RES) model developed by Kristin Kaschner to generate global predictions of marine mammal occurrences. According to the website on August 2013, the project held standardized distribution maps for over 17,300 species of fishes, marine mammals and invertebrates. The project is also expanding to incorporate freshwater species, with more than 600 biodiversity maps for freshwater fishes of the Americas available as at November 2009. predictions have been validated successfully for a number of species using independent data sets and the model was shown to perform equally well or better than other standard species distribution models, when faced with the currently existing suboptimal input data sets. In addition to displaying individual maps per species, provides tools to generate species richness maps by higher taxon, plus a spatial search for all species overlapping a specified grid square | https://en.wikipedia.org/wiki?curid=24956896 | 176,948 |
Roadometer (odometer) The roadometer was a 19th-century device like an odometer for measuring mileage, towed by a wagon, invented in 1847 by William Clayton and Orson Pratt, pioneers of The Church of Jesus Christ of Latter-Day Saints. The roadometer invented by William Clayton and Orson Pratt had cogs and gears made of wood. It recorded wheel revolutions by the mile and quarter-mile. They used their invention to provide an estimate of the distance their party traveled each day between Omaha, Nebraska, and Salt Lake City, Utah. Subsequently in 1849, it was attached to the wagon of Addison Pratt, to be used to record the daily mileage of the Jefferson Hunt wagon train that pioneered the Mormon Road from Salt Lake City to Los Angeles. | https://en.wikipedia.org/wiki?curid=48853442 | 328,796 |
The Illustrated Science and Invention Encyclopedia was an encyclopedia of books originally published in parts in the United Kingdom under the title "How It Works", by Marshall Cavendish Limited, and republished in the United States in 1974 by H.S. Stuttman Publishers in Westport, Connecticut, in 21 volumes (OCLC 3643238). It was supplanted by their "The New Illustrated Science and Invention Encyclopedia: How It Works", a 28 volume set edited by Donald Clarke and Mark Dartford, published in 1987 () (OCLC 1333004714), and then republished in 28 volumes from 1989 to 1993 (),(OCLC 28822057). A 2003 edition numbered 20 volumes, and was well reviewed. The encyclopedia was also published under the title "Science Horizons Year Books" and in a one-volume edition. | https://en.wikipedia.org/wiki?curid=8290337 | 216,331 |
IJssel Line The (Dutch: "IJssellinie") was the Dutch portion of the NATO Cold War line of defence for Western Europe during the 1950s and 1960s. It consisted of anti-aircraft and four-barrel machine gun bunkers, command and hospital bunkers, and many Ram and Sherman tank bunkers encased in concrete, leaving the turrets exposed. These elements were placed along the IJssel river. Movable floating dams were built in the Lower Rhine and Waal rivers. By diverting the flow of water from Germany into the IJssel River, the entire IJssel valley of could be inundated to form a line of defence against an anticipated Soviet invasion. Extensive flooding of the IJssel floodplains and the surrounding areas was intended as a substantial barrier between Nijmegen and Kampen. To ensure a sufficient amount of water for the area north of Deventer, a third movable floating dam was added at Olst. Flood waters were to be released from the IJssel River by means of 15 water intake works and 750 other water regulating structures. The flood water would then inundate large areas inside the winter dikes. Behind the line of defence, five motorised infantry divisions of the Dutch field army were to be positioned. The IJssel line of defense was intended to slow down a Soviet offensive, providing time for Allied support to reach the Netherlands | https://en.wikipedia.org/wiki?curid=35108877 | 220,629 |
List of the largest trading partners of Japan The 15 Largest Trading Partners of Japan These figures do not include services or foreign direct investment, but only trade in goods. The fifteen largest Japanese trading partners with their total trade (sum of imports and exports) in billions of US Dollars for calendar year 2017 are as follows: Japan is also the dominant export partner of the following: | https://en.wikipedia.org/wiki?curid=58461967 | 489,280 |
Brush hog Tractor dealers can recommend the right size brush hog for any of their tractors, or tractor and brush hog sizing charts are available on the Internet. Calculators used to estimate the time required to mow different size areas with different size cutters are also available and can be used to help decide which brush hog is the best investment for different situations. | https://en.wikipedia.org/wiki?curid=6921492 | 440,481 |
Prismane or 'Ladenburg benzene' is a polycyclic hydrocarbon with the formula CH. It is an isomer of benzene, specifically a valence isomer. is far less stable than benzene. The carbon (and hydrogen) atoms of the prismane molecule are arranged in the shape of a six-atom triangular prism—this compound is the parent and simplest member of the prismanes class of molecules. Albert Ladenburg proposed this structure for the compound now known as benzene. The compound was not synthesized until 1973. In the mid 19th century, investigators proposed several possible structures for benzene which were consistent with its empirical formula, CH, which had been determined by combustion analysis. The first, which was proposed by Kekulé in 1865, later proved to be closest to the true structure of benzene. This structure inspired several others to propose structures that were consistent with benzene's empirical formula; for example, Ladenburg proposed prismane, Dewar proposed Dewar benzene, and Koerner and Claus proposed Claus' benzene. Some of these structures would be synthesized in the following years. Prismane, like the other proposed structures for benzene, is still often cited in the literature, because it is part of the historical struggle toward understanding the mesomeric structures and resonance of benzene. Some computational chemists still research the differences between the possible isomers of CH. is a colourless liquid at room temperature | https://en.wikipedia.org/wiki?curid=2563306 | 27,806 |
War of the currents Feeks was killed almost instantly, his body falling into the tangle of wire, sparking, burning, and smoldering for the better part of an hour while a horrified crowd of thousands gathered below. The source of the power that killed Feeks was not determined although United States Illuminating Company lines ran nearby. Feeks' public death sparked a new round of people fearing the electric lines over their heads in what has been called the "Electric Wire Panic". The blame seemed to settle on Westinghouse since, Westinghouse having bought many of the lighting companies involved, people assumed Feeks' death was the fault of a Westinghouse subsidiary. Newspapers joined into the public outcry following Feeks' death, pointing out men's lives "were cheaper to this monopoly than insulated wires" and calling for the executives of AC companies to be charged with manslaughter. The October 13, 1889, New Orleans "Times-Picayune" noted "Death does not stop at the door, but comes right into the house, and perhaps as you are closing a door or turning on the gas you are killed." Harold Brown's reputation was rehabilitated almost overnight with newspapers and magazines seeking his opinion and reporters following him around New York City where he measured how much current was leaking from AC power lines. At the peak of the war of currents, Edison himself joined the public debate for the first time, denounced AC current in a November 1889 article in the "North American Review" titled "The Dangers of Electric Lighting" | https://en.wikipedia.org/wiki?curid=342086 | 236,978 |
Nitrophosphate process Today, only Yara (Norsk Hydro), BASF, Borealis Agrolinz Melamine GmbH, and GNFC still use the Odda process. Due to the alterations of the process by the various companies who employed it, the process is now generally referred to as the nitrophosphate process. Due to the byproduct ammonium nitrate which has lower value, the production of ammonium nitrophosphate fertilizer is not economical compared to diammonium phosphate which is produced from cheaper sulfuric acid or gypsum. | https://en.wikipedia.org/wiki?curid=767350 | 96,030 |
Gerontology The number and percentage of older adults living in the United States vary across the four different regions (Northeast, Midwest, West, and South) defined by the United States census. In 2010, the South contained the greatest number of people aged 65 years and older and 85 years and older. However, proportionately, the Northeast contains the largest percentage of adults aged 65 years and older (14.1%), followed by the Midwest (13.5%), the South (13.0%), and the West (11.9%). Relative to the Census 2000, all geographic regions demonstrated positive growth in the population of adults aged 65 years and older and 85 years and older. The most rapid growth in the population of adults aged 65 years and older was evident in the West (23.5%), which showed an increase from 6.9 million in 2000 to 8.5 million in 2010. Likewise, in the population aged 85 years and older, the West (42.8%) also showed the fastest growth and increased from 806,000 in 2000 to 1.2 million in 2010. It is worth highlighting that Rhode Island was the only state that experienced a reduction in the number of people aged 65 years and older, and declined from 152,402 in 2000 to 151,881 in 2010. Conversely, all states exhibited an increase in the population of adults aged 85 years and older from 2000 to 2010. Biogerontology is the sub-field of gerontology concerned with the biological aging process, its evolutionary origins, and potential means to intervene in the process | https://en.wikipedia.org/wiki?curid=436824 | 174,884 |
Ethology The monkey performed a different method and finally succeeded after trial-and-error. Another example familiar to some cat and dog owners is the ability of their animals to open doors. The action of humans operating the handle to open the door results in the animals becoming interested in the handle and then by trial-and-error, they learn to operate the handle and open the door. In local enhancement, a demonstrator attracts an observer's attention to a particular location. Local enhancement has been observed to transmit foraging information among birds, rats and pigs. The stingless bee ("Trigona corvina") uses local enhancement to locate other members of their colony and food resources. A well-documented example of social transmission of a behaviour occurred in a group of macaques on Hachijojima Island, Japan. The macaques lived in the inland forest until the 1960s, when a group of researchers started giving them potatoes on the beach: soon, they started venturing onto the beach, picking the potatoes from the sand, and cleaning and eating them. About one year later, an individual was observed bringing a potato to the sea, putting it into the water with one hand, and cleaning it with the other. This behaviour was soon expressed by the individuals living in contact with her; when they gave birth, this behaviour was also expressed by their young - a form of social transmission | https://en.wikipedia.org/wiki?curid=9425 | 189,805 |
Bioretention Therefore, removal and replacement of the bioretention layer will become necessary in areas with heavy metal pollutants in stormwater runoff to extend the life of the treatment system. | https://en.wikipedia.org/wiki?curid=13737048 | 90,268 |
Re-education in Communist Romania It was divided in two sections, one for the pupils, the other for former policemen and Siguranța members. The first section was reserved for those aged 16–20 years. Initially, the detention conditions were rather light, as they were allowed to receive packages (including books) and money, while once per month a guard was responsible for setting up a shopping list based on the prisoners demands. Food was decent while the prison administration – headed by warden Spirea Dumitrescu – was supportive towards them. After the prison reorganization, a weaving workshop is built, with the purpose of serving as a work reeducation center. Additionally, the administration started lectures based on the works of Marx and Engels. In time, the incarceration conditions deteriorated, reaching the same level as the other Romanian political prisons. A group of approximately 100 detainees was transferred there from Suceava in August 1949. Of those, more than half already joined the reeducation process. They set up a "Reeducation Committee" and approached the administration, seeking both support in their actions and retaliation against those who opposed it. By March 1950, they gained control over all the prison key positions, from the storehouse and workshop to the kitchen and post office. A political officer is assigned here, Iancu Burada at first, Dumitru Antonescu later. Joining the reeducation was optional, but came with a series of advantages, while those hostile were either isolated or eliminated from privileged jobs | https://en.wikipedia.org/wiki?curid=44990442 | 229,846 |
Brooks Hall Other ideas proposed for its reuse included a computer museum, an antiques mart, an expansion of the nearby parking garage, a food hall, a performance hall, a farmer's market, or a city-run television studio. In 2018, CMG Landscape Architecture unveiled three proposals to redesign the entire Civic Center open spaces, including a "Culture Connector" design variant that would open public access to through a canopy-covered set of stairs just north of Grove. | https://en.wikipedia.org/wiki?curid=56195833 | 349,500 |
Representation theory of the Lorentz group These can be thought of, in the passive view, as (instantly!) giving the coordinate system (and with it the observer) a velocity in a chosen direction. Finally, two special transformations are used to invert the coordinate system in space, space inversion, and in time, time reversal. In the first case, the space coordinate axes are reversed. The latter is reversal of the time "direction". This is thought of, in the passive view, as having the observer set their clock at "minus" what it shows and then have the clock's hands move counterclockwise. Physical time progresses forward. Mathematically the Lorentz group is defined as the set of transformations preserving the bilinear form where the left-hand side is the Minkowski inner product of two events in spacetime, and the right-hand side is the spacetime interval, see classical group for mathematical detail. In the spacetime of special relativity, called Minkowski space, space and time are interwoven. Thus the four coordinates of points in spacetime, called events, change in ways unexpected before the advent of special relativity, with time dilation and length contraction as two immediate consequences. The four-dimensional matrices of Lorentz transformations compose the Lorentz group. Its elements represent symmetries, and just like physical objects can be rotated using rotation matrices, the same physical objects (whose coordinates now include the time coordinate) can be "transformed" using the matrices representing Lorentz transformations | https://en.wikipedia.org/wiki?curid=2249718 | 428,730 |
Robert Burrell Robert Burrell, , is a Canadian biomedical engineer, currently the Canada Research Chair at University of Alberta. Burrell was inducted into the Alberta Order of Excellence on October 17, 2019. | https://en.wikipedia.org/wiki?curid=53837246 | 187,243 |
EPUB is an e-book file format that uses the ".epub" file extension. The term is short for "electronic publication" and is sometimes styled "ePub". is supported by many e-readers, and compatible software is available for most smartphones, tablets, and computers. is a technical standard published by the International Digital Publishing Forum (IDPF). It became an official standard of the IDPF in September 2007, superseding the older Open eBook standard. The Book Industry Study Group endorses 3 as the format of choice for packaging content and has stated that the global book publishing industry should rally around a single standard. The format is implemented as an archive file consisting of HTML files carrying the content, along with images and other supporting files. is the most widely supported vendor-independent XML-based (as opposed to PDF) e-book format; that is, it is supported by almost all hardware readers, except for Kindle. A successor to the Open eBook Publication Structure, 2.0 was approved in October 2007, with a maintenance update (2.0.1) approved in September 2010. The 3.0 specification became effective in October 2011, superseded by a minor maintenance update (3.0.1) in June 2014. New major features include support for precise layout or specialized formatting (Fixed Layout Documents), such as for comic books, and MathML support. The current version of is 3.1, effective January 5, 2017 | https://en.wikipedia.org/wiki?curid=20432638 | 402,615 |
A/B testing Many positions rely on the data from A/B tests, as they allow companies to understand growth, increase revenue, and optimize customer satisfaction. Version A might be the currently used version (control), while version B is modified in some respect (treatment). For instance, on an e-commerce website the purchase funnel is typically a good candidate for A/B testing, as even marginal decreases in drop-off rates can represent a significant gain in sales. Significant improvements can sometimes be seen through testing elements like copy text, layouts, images and colors, but not always. In these tests, users only see one of two versions, as the goal is to discover which of the two versions is preferable. Multivariate testing or multinomial testing is similar to A/B testing, but may test more than two versions at the same time or use more controls. Simple A/B tests are not valid for observational, quasi-experimental or other non-experimental situations, as is common with survey data, offline data, and other, more complex phenomena. has been marketed by some as a change in philosophy and business strategy in certain niches, though the approach is identical to a between-subjects design, which is commonly used in a variety of research traditions. as a philosophy of web development brings the field into line with a broader movement toward evidence-based practice | https://en.wikipedia.org/wiki?curid=9332179 | 472,825 |
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