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42,790,440 | https://en.wikipedia.org/wiki/Jean-Claude%20Delam%C3%A9therie | Jean-Claude Delamétherie (also de La Métherie, de Lamétherie, 4 September 1743 – 1 July 1817) was a French mineralogist, geologist and paleontologist.
Career
Delamétherie was born in La Clayette. He edited Journal de physique, de chimie, d'histoire naturelle et des arts from 1785. He was elected member of Leopoldina in 1792. He was a supporter of the French Revolution, but opposed to the Jacobins, and was forced to leave Paris during the Reign of Terror, interrupting publication of the Journal de physique until 1797.
Numerous minerals were first systematically described by Delamétherie.
In 1795, Delamétherie first described the Lherzolite (which he named after the site of its discovery, Étang de Lers in the Pyrenees).
Delamétherie was an advocate of transmutation of species. He was an atheist and materialist. Delamétherie held similar views to Jean-Baptiste Lamarck but differed on his views on the history of earth. According to science historian Pietro Corsi:
Delamétherie believed in a primeval ocean in which rocks and life were formed through countless ages thanks to processes of crystallization, and maintained that all life forms known to man developed from a restricted number of prototypes equally generated by specific forms of crystallization.
Delamétherie was supportive of the inheritance of acquired characteristics and suspected that Lamarck had copied some of his ideas.
Publications
Principes de la philosophie naturelle, 1777, 2nd ed. 1787.
Essai Analytique sur l'Air pur, et les différentes Espèces d'Air, 1785 (online)
Vues physiologiques sur l’organisation animale et végétale, 1780 (online).
De la nature des êtres existans, 1805 (online).
Théorie de la Terre, 1795, 2nd ed. 1797; German translation (1797) Theorie der Erde, 1797 (Bd. 1 online).
Leçons de minéralogie, 1811.
Leçons de géologie, 1816.
References
Pietro Corsi: Lamarck. Genèse et enjeux du transformisme. 1770-1830, CNRS Édition, 2001, .
External links
de la Métherie's (1797–98) Theorie der Erde (3 vols.) - digital facsimile from the Linda Hall Library
1743 births
1817 deaths
French atheists
French geologists
French materialists
French mineralogists
Proto-evolutionary biologists | Jean-Claude Delamétherie | [
"Biology"
] | 529 | [
"Non-Darwinian evolution",
"Biology theories",
"Proto-evolutionary biologists"
] |
42,790,711 | https://en.wikipedia.org/wiki/Plant%20secretory%20tissue | The tissues that are concerned with the secretion of gums, resins, volatile oils, nectar latex, and other substances in plants are called secretory tissues. These tissues are classified as either laticiferous tissues or glandular tissues.
Introduction
Cells or organizations of cells which produce a variety of secretions. The secreted substance may remain deposited within the secretory cell itself or may be excreted, that is, released from the cell. Substances may be excreted to the surface of the plant or into intercellular cavities or canals. Some of the many substances contained in the secretions are not further utilized by the plant (resins, rubber, tannins, and various crystals), while others take part in the functions of the plant (enzymes and hormones). Secretory structures range from single cells scattered among other kinds of cells to complex structures involving many cells; the latter are often called glands.
Epidermal hairs of many plants are secretory or glandular. Such hairs commonly have a head composed of one or more secretory cells borne on a stalk. The hair of a stinging needle is bulbous below and extends into a long, fine process above. If one touches the hair, its tip breaks off, the sharp edge penetrates the skin, and the poisonous secretion is released.
Glands secreting a sugary liquid—the nectar—in flowers pollinated by insects are called nectaries. Nectaries may occur on the floral stalk or on any floral organ: sepal, petal, stamen, or ovary.
The hydathode structures discharge water—a phenomenon called guttation through openings in margins or tips of leaves.
The water flows through the xylem to its endings in the leaf and then through the intercellular spaces of the hydathode tissue toward the openings in the epidermis. Strictly speaking, such hydathodes are not glands because they are passive with regard to the flow of water.
Some carnivorous plants have glands that produce secretions
capable of digesting insects and small animals. These glands
occur on leaf parts modified as insect-trapping structures. In
the sundews ( Drosera ) the traps bear stalked glands, called
tentacles. When an insect lights on the leaf, the tentacles bend
down and cover the victim with a mucilaginous secretion, the
enzymes of which digest the insect. See insectivorous plants.
Resin ducts are canals lined with secretory cells that release
resins into the canal. Resin ducts are common in gymnosperms
and occur in various tissues of roots, stems, leaves, and
reproductive structures.
Gum ducts are similar to resin ducts and may contain resins,
oils, and gums. Usually, the term gum duct is used with
reference to the dicotyledons, although gum ducts also may
occur in the gymnosperms.
Oil ducts are intercellular canals whose secretory cells produce
oils or similar substances. Such ducts may be seen, for
example, in various parts of the plant of the carrot family
(Umbelliferae).
Laticifers are cells or systems of cells containing latex, a milky
or clear, colored or colorless liquid. Latex occurs under
pressure and exudes from the plant when the latter is cut.
Laticiferous tissues
These consist of thick walled, greatly elongated and much
branched ducts containing a milky or yellowish colored
juice known as latex. They contain numerous nuclei
which lie embedded in the thin lining layer of protoplasm.
They are irregularly distributed in the mass of parenchymatous cells.
Laticiferous ducts, in which latex are found are again two types-
Latex cell or non-articulate latex ducts
Latex vessels or articulate latex
Latex cells
Also called as "non-articulate latex ducts", these ducts are independent units which extend as branched structures for long distances in the plant body.
They originates as minute structures, elongate quickly and by repeated branching ramify in all directions but do not fuse together.
Thus a network is not formed as in latex vessels.
Latex vessel
Also called "articulate latex ducts", these ducts or vessels are the result of anastamosis of many cells.
They grow more or less as parallel ducts which by means of branching and frequent anastomoses form a complex network.
Latex vessels are commonly found in many angiosperm families Papaveraceae, Compositae, Euphorbiaceae, Moraceae, etc.
Function
The function of laticiferous ducts is not clearly understood. They may also act as food storage organs or as reservoir of waste products, or as translocatory tissues.
Glandular tissues
This tissue consists of special structures; the glands. These glands contain some secretory or excretory products.
A gland may consist of isolated cells or a small group of cells with or without a central cavity.
They are of various kinds and may be internal or external.
Internal glands are
Oil-gland secreting essential oils, as in the fruits and leaves of orange, lemon.
Mucilage secreting glands, as in the betel leaf
Glands secreting gum, resin, tannin, etc.
Digestive glands secreting enzymes or digestive agents
Special water secreting glands at the tip of veins
External glands are commonly short hairs tipped by glands. They are
water-secreting hairs or glands,
Glandular hairs secreting gum like substances as in tobacco, plumbago, etc.
Glandular hairs secreting irritating, poisonous substances, as in nettles
Honey glands, as in carnivorous plants.
See also
Vascular tissue
Hydathode
References
Raven, Peter H., Evert, Ray F., & Eichhorn, Susan E. (1986). Biology of Plants (4th ed.). New York: Worth Publishers. .
External links
Intro to Plant Structure Contains diagrams of the plant tissues, listed as an outline.
Plant anatomy
Plant physiology | Plant secretory tissue | [
"Biology"
] | 1,233 | [
"Plant physiology",
"Plants"
] |
42,791,361 | https://en.wikipedia.org/wiki/Polyhexahydrotriazine | Polyhexahydrotriazines (PHTs) are polymers of hexahydro-1,3,5-triazines, a class of heterocyclic compounds with the formula (CH2NR)3. They are among the strongest known thermosetting plastics and are stable to solvents at pH > 3, but decompose to the monomers in acidic solutions.
Synthesis
Various PHTs have been synthesized at room temperature in one step in the early 2000s; they were considered impractical due to their poor mechanical properties. It was later elucidated that, due to the temperature of synthesis, the poor mechanical properties observed were likely due to poly(hemiaminal) formation and not PHT formation.
In 2014, Jeanette Garcia, Gavin Jones and a team of researchers at IBM Almaden Research Center, US, developed a new type of PHT (1.6) in what has been called a "happy accident". Garcia had left out a reagent when preparing her mix of chemicals. When low heat was applied to the beaker of paraformaldehyde and 4,4ʹ-oxydianiline, it had created a hemiaminal dynamic covalent network (HDCN). Heating the HDCN to 200 °C transformed it into two new polymers: PHT 1.6 and an organogel known as polyhemiaminal (PHA)
Properties
The PHT 1.6 has a yellowish color. It is resistant to solvents at pH > 3, but decomposes into monomers within a day in acidic solutions at pH < 2. This property is unusual for thermosetting plastics and allows easy recycling. This PHT has a Young's modulus exceeding 10 GPa, which is among the highest for a thermosetting plastic; it can be further increased by ~50% by dispersing carbon nanotubes in the polymer. The PHT is brittle, and cracks when strained to 1%. Upon heating, it softens at a glass transition temperature of ~190 °C and decomposes at ~300 °C.
Possible uses
A number of industries could benefit from the use of PHT in manufacturing parts and devices due to its recyclability, lightweight structure, and strength:
Aerospace - PHT used in the development of wings, tails, bodies, and rutters would provide a lightweight, durable vessel for both commercial and personal aircraft applications. PHT in combination with PHA could be used to adhere aircraft pieces that are exposed to harsh environmental conditions and high speeds.
Automotive - When manufacturing automobiles, PHT would provide a light, high performance option for auto body parts such as panels, hoods, and exterior trim pieces.
Semiconductors - Semiconductor chips and transistors made of PHT would allow for the reworking of defective electronics rather than having to discard the equipment.
References
Amines
Triazines
Organic polymers
Thermosetting plastics | Polyhexahydrotriazine | [
"Chemistry"
] | 602 | [
"Organic polymers",
"Functional groups",
"Organic compounds",
"Amines",
"Bases (chemistry)"
] |
42,791,761 | https://en.wikipedia.org/wiki/Quantum%20compass | The terminology quantum compass often relates to an instrument which measures relative position using the technique of atom interferometry. It includes an ensemble of accelerometers and gyroscope based on quantum technology to form an inertial navigation unit.
Description
Work on quantum technology based inertial measurement units (IMUs), the instruments containing the gyroscopes and accelerometers, follows from early demonstrations of matter-wave based accelerometers and gyrometers. The first demonstration of onboard acceleration measurement was made on an Airbus A300 in 2011.
A quantum compass contains clouds of atoms frozen using lasers. By measuring the movement of these frozen particles over precise periods of time the motion of the device can be calculated. The device would then provide accurate position in circumstances where satellites are not available for satellite navigation, e.g. a fully submerged submarine.
Various defence agencies worldwide, such as the US DARPA and the United Kingdom Ministry of Defence have pushed the development of prototypes for future uses in submarines and aircraft.
In 2024, researchers from the Centre for Cold Matter of Imperial College, London, tested an experimental quantum compass on an underground train on London's District line. During the same year, scientists at the Sandia National Laboratories announced they were able to perform spatial quantum sensing using silicon photonic microchip components, a significant advancement towards the development of compact, portable and inexpensive quantum compass devices.
References
Measuring instruments
Speed sensors
Vehicle parts
Vehicle technology | Quantum compass | [
"Physics",
"Technology",
"Engineering"
] | 303 | [
"Speed sensors",
"Quantum mechanics",
"Measuring instruments",
"Vehicle technology",
"Mechanical engineering by discipline",
"Vehicle parts",
"Components",
"Quantum physics stubs"
] |
42,791,858 | https://en.wikipedia.org/wiki/T%20Ursae%20Minoris | T Ursae Minoris (T UMi) is a variable star in the constellation Ursa Minor, located west-southwest of 3 Ursae Minoris toward the western border of the constellation with Draco.
Properties
A red giant ranging between spectral types M4e and M6e and with a surface temperature of , T Ursae Minoris is a long period semiregular variable star ranging from magnitude 7.8 to 15. These are highly evolved ageing stars that are on the asymptotic giant branch, their wide range in magnitude making them ideal targets for monitoring by amateur star observers.
T Ursae Minoris has been monitored closely since 1905. Up until 1979, its brightness had varied over a period of 310 to 315 days and it was classified as a Mira variable. However, from 1979 its period decreased suddenly to 274 days, and appeared to be decreasing by 2.75 days a cycle since. Variable star observers Janet Mattei and Grant Foster proposed that the star had just undergone a shell helium flash – a point at which "the helium shell around the dense core of the star reaches a critical mass and ignites", which "influences the star's pulsation via changes in surface luminosity and radius". By mid 2008, its period had decreased to 230 days, before changing to pulsation as a semiregular variable star, with a dominant period of 113.6 days. This has been the most dramatic change of any Mira variable. The lack of technetium in its spectrum indicates it is not as advanced in age as some other Mira-type stars, as it has either not yet dredged up this sort of material from its core or is of insufficient mass for this to occur.
A model of T Ursae Minoris shows that following a thermal pulse, its properties are expected to change over a period of only a few years. The period would reduce gradually for about 35 years and then decrease dramatically from about 300 days to about 100 days as the pulsations switch from the fundamental mode to the first overtone. At the same time, the radius and luminosity would decrease from around and respectively to about and . The radius and luminosity would then increase slowly over the next few thousand years to become larger than before the thermal pulse. Multiple thermal pulses are expected to occur in stars at this stage of their lives, about 100,000 years apart, with the star become gradually larger and cooler until it eventually sheds its outer layers to become a white dwarf. T Ursae Minoris is expected to reach its smallest size in about 50 years time, then begin to slowly increase in size and luminosity again.
References
Ursa Minor
M-type giants
Mira variables
Ursae Minoris, T
118556
Emission-line stars
J13344108+7325530 | T Ursae Minoris | [
"Astronomy"
] | 583 | [
"Ursa Minor",
"Constellations"
] |
42,791,912 | https://en.wikipedia.org/wiki/Vitrimers | Vitrimers are a class of plastics, which are derived from thermosetting polymers (thermosets) and are very similar to them. Vitrimers consist of molecular, covalent networks, which can change their topology by thermally activated bond-exchange reactions. At high temperatures, they can flow like viscoelastic liquids; at low temperatures, the bond-exchange reactions are immeasurably slow (frozen), and the Vitrimers behave like classical thermosets at this point. Vitrimers are strong glass formers. Their behavior opens new possibilities in the application of thermosets, such as a self-healing material or simple processibility in a wide temperature range.
Besides epoxy resins based on diglycidyl ether of bisphenol A, other polymer networks have been used to produce vitrimers, such as aromatic polyesters, polylactic acid (polylactide), polyhydroxyurethanes, epoxidized soybean oil with citric acid, and polybutadiene. Vitrimers were termed as such in the early 2010s by French researcher Ludwik Leibler from the CNRS.
Background and significance
Thermoplastics are easy to process, but corrode easily by chemicals and mechanical stress, while the opposite is true of thermosets. These differences arise from how the polymer chains are held together.
Historically, thermoset polymer systems that were processable by virtue of topology changes within the covalent networks as mediated by bond exchange reactions were also developed by James Economy’s group at UIUC in the 1990s including consolidation of thermoset composite laminae. As well, the Economy group conducted studies employing secondary ion mass spectrometry (SIMS) on deuterated and undeuterated fully cured vitrimer layers to discriminate the length scales (<50 nm) for physical interdiffusion between vitrimers constituent atoms – providing evidence towards eliminating physical interdiffusion of the polymer chains as the governing mechanism for bonding between vitrimer layers.
Thermoplastics are made of covalent bond molecule chains, which are held together by weak interactions (e.g., van der Waals forces). The weak intermolecular interactions lead to easy processing by melting (or in some cases also from solution), but also make the polymer susceptible to solvent degradation and to creep under constant load. Thermoplastics can be deformed reversibly above their glass-transition temperature or their crystalline melting point and be processed by extrusion, injection molding, and welding.
Thermosets, on the other hand, are made of molecular chains which are interconnected by covalent bonds to form a stable network. Thus, they have outstanding mechanical properties and thermal and chemical resistance. They are an indispensable part of structural components in automotive and aircraft industries. Due to their irreversible linking by covalent bonds, molding is not possible once the polymerization is completed. Therefore, they must be polymerized in the desired shape, which is time-consuming, restricts the shape and is responsible for their high price.
Given this, if the chains can be held together with reversible, strong covalent bonds, the resultant polymer would have the advantages of both thermoplastics and thermosets, including high processability, repairability, and performance. Vitrimers combine the desirable properties of both classes: they have the mechanical and thermal properties of thermosets and can be also molded under the influence of heat. Vitrimers can be welded like silicon glasses or metals. Welding by simple heating allows the creation of complex objects. Vitrimers could thus be a new and promising class of materials with many uses.
The term vitrimer was created by the French researcher Ludwik Leibler, head of laboratory at CNRS, France's national research institute. In 2011, Leibler and co-workers developed silica-like networks using the well-established transesterification reaction of epoxy and fatty dicarboxylic or tricarboxylic acids. The synthesized networks have both hydroxyl and ester groups, which undergo exchange reactions (transesterifications) at high temperatures, resulting in the ability of stress relaxation and malleability of the material. On the other hand, the exchange reactions are suppressed to a great extent when the networks are cooled down, leading to a behavior like a soft solid. This whole process is based only on exchange reactions, which is the main difference from that of thermoplastics.
Functional principle
Glass and glass former
If the melt of an (organic) amorphous polymer is cooled down, it solidifies at the glass-transition temperature Tg. On cooling, the hardness of the polymer increases in the neighborhood of Tg by several orders of magnitude. This hardening follows the Williams-Landel-Ferry equation, not the Arrhenius equation. Organic polymers are thus called fragile glass formers. Silicon glass (e.g., window glass), is in contrast labelled as a strong glass former. Its viscosity changes only very slowly in the vicinity of the glass-transition point Tg and follows the Arrhenius law. This is what permits glassblowing. If one would try to shape an organic polymer in the same manner as glass, it would at first firmly and fully liquefy very slightly above Tg. For a theoretical glassblowing of organic polymers, the temperature must be controlled very precisely.
Until 2010, no organic strong glass formers were known. Strong glass formers can be shaped in the same way as glass (silicon dioxide) can be. Vitrimers are the first such material discovered, which can behave like viscoelastic fluid at high temperatures. Unlike classical polymer melts, whose flow properties are largely dependent on friction between monomers, vitrimers become a viscoelastic fluid because of exchange reactions at high temperatures as well as monomer friction. These two processes have different activation energies, resulting in a wide range of viscosity variation. Moreover, because the exchange reactions follow Arrhenius' Law, the change of viscosity of vitrimers also follows an Arrhenius relationship with the increase of temperature, differing greatly from conventional organic polymers.
Effect of transesterification and temperature influence
The research group led by Ludwik Leibler demonstrated the operating principle of vitrimers at the example of epoxy thermosets. Epoxy thermosets can be represented as vitrimers, when transesterification reactions can be introduced and controlled. In the studied system, carboxylic acids or carboxylic acid anhydrides must be used as hardeners. A topology change is possible by transesterification reactions which do not affect the number of links or the (average) functionality of the polymer, meaning that neither the decomposition of polymer linkages nor the decrease of integrity of polymers happens when transesterification reactions take place. Thus, the polymer can flow like a viscoelastic liquid at high temperatures. During the cooling phase, the transesterification reactions are slowed down, until they finally freeze (be immeasurably slow). Below this point vitrimers behave like normal, classical thermosets. The shown case-study polymers showed an elastic modulus of 1 MPa to 100 MPa, depending on the bonding network density.
The concentration of ester groups in vitrimers is shown to have a huge influence on the rate of transesterification reactions. In the work done by Hillmyer, et al., about polyactide vitrimers, they demonstrated that the more ester groups present in the polymer, the faster the rates of relaxation will be, leading to better self-healing performance. Polyactide vitrimers which are synthesized by cross linking reactions of hydroxylterminated 4-arm star-shaped poly((±)-lactide) (HTSPLA) and methylenediphenyl diisocyanate (MDI) with the presence of cross-linking and transesterification catalyst stannous(II) octoate [Sn(Oct)2], have many more ester groups than all previous vitrimers; therefore, this material has a significantly high stress relaxing rate compared to other polyester based vitrimer systems.
Applications
There are many uses imaginable on this basis. A surfboard made of vitrimers could be brought into a new shape, scratches on a car body could be cured and cross-linked plastic or synthetic rubber items could be welded. Vitrimers, which are prepared from metathesis of dioxaborolanes with different commercially available polymers, can have both good processibility and outstanding performance, such as mechanical, thermal, and chemical resistance. The polymers that can be utilized in such methodology range from poly(methylmethacrylate), polyimine, polystyrene, to polyethylene with high density and cross-linked robust structures, which makes this preparative method of vitrimers able to be applied to a wide range of industries. Recent NASA-funded work on reversible adhesives for in-space assembly has used a high-performance vitrimer system called aromatic thermosetting copolyester (ATSP) as the basis for coatings and composites reversibly bondable in the solid state – providing new possibilities for the assembly of large, complex structures for space exploration and development. Start-up Mallinda Inc. claims to have applications across the composites market from wind energy, sporting goods, automotive, aerospace, marine, and carbon fiber reinforced pressure vessels among others.
External links
ESPCI ParisTech
ATSP Innovations
Mallinda Inc Imine-linked Vitrimers
References
Polymers
French inventions
21st-century inventions | Vitrimers | [
"Chemistry",
"Materials_science"
] | 2,041 | [
"Polymers",
"Polymer chemistry"
] |
42,792,244 | https://en.wikipedia.org/wiki/RIOT%20%28operating%20system%29 | RIOT is a small operating system for networked, memory-constrained systems with a focus on low-power wireless Internet of things (IoT) devices. It is open-source software, released under the GNU Lesser General Public License (LGPL).
Background
It was initially developed by Free University of Berlin (FU Berlin), French Institute for Research in Computer Science and Automation (INRIA) and the Hamburg University of Applied Sciences (HAW Hamburg). RIOT's kernel is mostly inherited from FireKernel, which was originally developed for sensor networks. In 2015, one of the co-developers, Matthias Wählisch was awarded the Young Scientist Award of the Forum for Excellent Young Scientists for the contributions of his team to the open source operating system RIOT. In 2016, the ED STIC Doctoral Prize 2017 of the University of Paris-Saclay was awarded to another co-founder, Oliver Hahm for his contribution to the project.
Technical aspects
RIOT is based on a microkernel architecture. In contrast to other operating systems with similarly low memory use (such as TinyOS or Contiki), RIOT allows application software programming with the programming languages C and C++, and Rust, also by an experimental application programming interface (API). It has full multithreading and real-time abilities. Secure Sockets Layer (SSL) and successor Transport Layer Security (TLS) are supported by popular libraries such as wolfSSL.
RIOT runs on processors of 8 bits (such as AVR Atmega), 16 bits (such as TI MSP430), and 32 bits (such as ARM Cortex). A native port also enables RIOT to run as a Linux or macOS process, enabling use of standard developing and debugging tools such as GNU Compiler Collection (GCC), GNU Debugger, Valgrind, Wireshark, etc. RIOT is partly Portable Operating System Interface (POSIX) compliant.
RIOT provides multiple network stacks, including IPv6, 6LoWPAN, or content centric networking and standard protocols such as RPL, User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and CoAP.
Source code
RIOT source code is available on GitHub, and developed by an international community of open source developers.
See also
Contiki
TinyOS
FreeRTOS
Nano-RK
Zephyr
Comparison of real-time operating systems
References
External links
ARM operating systems
Embedded operating systems
Free software operating systems
Internet of things
Microkernels
Microkernel-based operating systems
MIPS operating systems
Real-time operating systems | RIOT (operating system) | [
"Technology"
] | 530 | [
"Wireless networking",
"Wireless sensor network",
"Real-time computing",
"Real-time operating systems"
] |
42,792,275 | https://en.wikipedia.org/wiki/Rigging%20%28material%20handling%29 | Rigging is both a noun, the equipment, and verb, the action of designing and installing the equipment, in the preparation to move objects. A team of riggers design and install the lifting or rolling equipment needed to raise, roll, slide or lift objects such as heavy machinery, structural components, building materials, or large-scale fixtures with a crane, hoist or block and tackle.
Rigging comes from rig, to set up or prepare. Rigging is the equipment such as wire rope, turnbuckles, clevis, jacks used with cranes and other lifting equipment in material handling and structure relocation. Rigging systems commonly include shackles, master links and slings, and lifting bags in underwater lifting.
In the United States the Occupational Safety and Health Administration (OSHA) regulates workplace safety including rigging in CFR 1926.251. The Health and Safety Executive is responsible for the matters in the United Kingdom.
Equipment
Winch
Procedures
Safety
Gallery
See also
References
External links
3.5 minute video on some basic cable rigging safety
OSHA 1926.251 Rigging equipment for material handling
what is rigging equipment
Material-handling equipment
Lifting equipment | Rigging (material handling) | [
"Physics",
"Technology"
] | 235 | [
"Physical systems",
"Machines",
"Lifting equipment"
] |
42,792,432 | https://en.wikipedia.org/wiki/Z%20Ursae%20Minoris | Z Ursae Minoris (Z UMi) is a carbon star and R Coronae Borealis variable in the constellation Ursa Minor.
Z Ursae Minoris was discovered to be a variable star in 1934. It was catalogued as a probable Mira variable, due to its red colour and variations over several hundred days. It was discovered to be a carbon star in a survey published in 1985, and subsequently found also to be hydrogen-deficient. After fading by almost six magnitudes in 1992, it was classified as an R Coronae Borealis variable. It was confirmed as an R Coronae Borealis variable, one of the coolest in the class, after its spectrum was analysed in 2006.
References
Ursa Minor
R Coronae Borealis variables
Ursae Minoris, Z
Carbon stars | Z Ursae Minoris | [
"Astronomy"
] | 167 | [
"Ursa Minor",
"Constellations"
] |
42,793,721 | https://en.wikipedia.org/wiki/Sodium%20cyanate | Sodium cyanate is the inorganic compound with the formula NaOCN. A white solid, it is the sodium salt of the cyanate anion.
Structure
The anion is described by two resonance structures:
The salt adopts a body centered rhombohedral crystal lattice structure (trigonal crystal system) at room temperature.
Preparation
Sodium cyanate is prepared industrially by the reaction of urea with sodium carbonate at elevated temperature.
2OC(NH2)2 + Na2CO3 → 2Na(NCO) + CO2 + 2NH3 + H2O
Sodium allophanate is observed as an intermediate:
It can also be prepared in the laboratory by oxidation of a cyanide in aqueous solution by a mild oxidizing agent such as lead oxide.
Uses and reactions
The main use of sodium cyanate is for steel hardening.
Sodium cyanate is used to produce cyanic acid, often in situ:
This approach is exploited for condensation with amines to give unsymmetrical ureas:
Such urea derivatives have a range of biological activity.
See also
Cyanate
References
Cyanates
Sodium compounds | Sodium cyanate | [
"Chemistry"
] | 242 | [
"Inorganic compounds",
"Functional groups",
"Inorganic compound stubs",
"Cyanates"
] |
42,794,518 | https://en.wikipedia.org/wiki/Alfred%20Ubbelohde | Alfred René Jean Paul Ubbelohde FRS (1907–1988) was a Belgian-born English physical chemist.
Biography
Alfred Ubbelohde (usually known as Paul) was born In Antwerp on 14 December 1907, the third son of François Christian J. Ubbelohde, a merchant, and Angele (née Verspreeuwen). The family moved to England at the outbreak of the first world war. Paul contracted polio just a few months later, leaving him a stoop and a paralysed right arm. He was naturalized British in his mid-twenties.
Ubbelohde attended Colet Court school in Barnes, London from 1920, and then St Paul’s. He was interested in chemistry, pure mathematics and
English literature. He chose chemistry and won a scholarship to Christ Church, Oxford from where he graduated with First Class Honours in 1930.
Ubbelohde spent five more years at Oxford, undertaking postgraduate research at the Clarendon with Sir Alfred Egerton, FRS. They published together on the occlusion of hydrogen by palladium. and the oxidation of hydrocarbons.
During his time at Oxford, Ubbelohde spent a year (1931–32) in the laboratory of Professor Arnold Eucken at the Institut für physikalische Chemie, Göttingen. During this time with he spent time with Max Born and was also able to go through “the entire Leiden glass-blowing course after working hours”.
In 1936, Paul Ubbelohde was awarded the Dewar Fellowship of the Royal Institution (RI), then under the direction of Sir William Bragg. Here he met many talented scientists, including Kathleen Lonsdale, John Monteath Robertson and Hermann Arthur Jahn. He often declared that “the most formative period of his scientific life was spent at the Royal Institution”. Another key contact at the RI was Sir Robert Robinson. In 1939, the Royal Arsenal was vulnerable to enemy attack, and so the Research Department was dispersed to University College, Swansea. Robertson (then aged 70) left the RI to take charge of it. Ubbelohde joined him in June 1940; he was Principal Experimental Officer in charge of a group working on the theory and practice of explosion and detonation.
In 1945, shortly after VE Day, Ubbohde’s war work came to an end, and he was appointed Professor of Chemistry at Queen's University Belfast. Here “he built up a vibrant department of physical chemistry. His own research included transport properties and the combustion of gaseous hydrocarbons; the diffusion, ultrasonic dispersion and viscosity of liquids; and the interaction of alkali metals with aromatic hydrocarbons. He also studied the intercalation of guest species by graphitic hosts”.
In 1954 Ubbelohde moved from Belfast to take up the position of Professor of Thermodynamics at Imperial College London, accompanied by a number of junior colleagues and students from Queen’s. In 1961 he became Head of Department, a post which he held until his retirement in 1975. During his time at Imperial Ubbelohde’s researches covered a wide range, including carbon, graphite and intercalation compounds; pyrolytic graphites; ionic melts; and detonation.
In his memoir on Ubbelohde Felix Weinberg stated that “Although a few friends were privileged to remain close to him from his youth and benefited from his kindness, Paul Ubbelohde remained a very private person throughout his life and many of his colleagues never felt quite at ease with him. ‘He was the one Governor (of St Paul’s School) whom I knew longest’ wrote the late Dr M A Grace, FRS, ‘but about whom I knew least. His conversation was wide-ranging - physics, food, wine, pigs, farming, art, etc., but rarely about people’”.
The Times obituary noted that:
Awards and honours
The Dewar Fellowship of the Royal Institution in 1936
DSc by Oxford University Ubbelohde in 1941
Fellow of the Royal Institute of Chemistry (FRIC) in 1946
Fellow of the Royal Society in 1951
Fellow of the Institute of Physics (FInstP) in 1957
Appointed CBE in 1961
Academician of the Pontifical Academy of Sciences in 1968
The Combustion Institute’s Alfred C. Egerton Gold Medal in 1970
The Messel Medal (the premier award of the Society of Chemical Industry) in 1972
Honorary DSc by Queen’s University Belfast 1972
The George Skakel Memorial Award of the American Carbon Society in 1975
The Paul Lebeau Gold Medal of the Société des Hautes Temperatures et Réfractaires in 1975
Honorary Degrees from the Universities of Padua, Nancy and the Université Libre of Brussels
Honorary Fellow of the City and Guilds Institute
Freeman of the City of London
Publications
Source:
An Introduction to Modern Thermodynamical Principles. Oxford: Clarendon Press, 1937
Time and Thermodynamics. London: Oxford University Press, 1947
Man and Energy ... Illustrated. London: Hutchinson's Scientific & Technical Publications, 1954
Melting and Crystal Structure. Oxford: Clarendon Press, 1955
Thermodynamics in the World of To-day, etc. London: 1955
Graphite and its Crystal Compounds (with F A Lewis) Oxford: Clarendon Press, 1960
The Molten State of Matter: Melting and Crystal Structure. Chichester; New York: Wiley, 1979
Miss Georgina Greene
When Paul Ubbelohde became well-established as Head of Department at Imperial College he advertised for a departmental secretary. He needed “a secretary or personal assistant who firmly controls access and rations unexpected intrusions […] Miss Georgina Greene acquired world-wide renown for her effectiveness in that role during Ubbelohde’s period at Imperial College. One scientist who knew her reported that “Ubbelohde’s dazzling and formidable secretary Georgina Greene became a dominating influence in the Department. Georgina had a two-way mirror connecting her office with that of Ubbelohde and vetted all those who wanted to speak to the head of Department”. Gay notes that "She wielded power over the staff and was understandably resented".
Some years earlier, Miss Greene was involved in an unfortunate episode. In February 1957 Lord Worsley (John Edward Pelham, the 7th Earl of Yarborough) announced his forthcoming marriage to Georgina,“secretary to a professor in London”. Less than two months later it was announced, without explanation, that the marriage would not now take place. On 12 December of that year Lord Worsley married Florence Ann Petronel Duffin (née Upton) at Caxton Hall.
Greene was born in Abbeyleix, Ireland in 1925. She was given considerable responsibility while working for Ubbelohde. She worked with Dudley Maurice Newitt on the design and decoration of the Senior Common Room in the Roderick Hill building. She also recollected that “Professor Ubbelohde required a large house, not least ‘to keep all his books in’. The 17th century Platts Farm nestles in the beautiful rolling Sussex countryside with Rudyard Kipling’s house just visible on the horizon. [She] was left to bid for the farm during one of Professor Ubbelohde’s absences in South America and was so confident of his approval that she exceeded the previously agreed maximum by a generous margin”.
Paul Ubbelohde obviously thought so highly of Georgina Green that he left her all his silver plate, his car and £20,000. She in turn left in her will to “The Worshipful Company of Mercers for the Ubbelohde Fund in appreciation of the life of H. E. Professor A R J P Ubbelohde CBE FRS the sum of £30,000”.
Miss Georgina Mary Greene died on 9 April 2015 at the White Lodge Care Home in Braydon, Wiltshire; she left an estate with a net worth of £1,480,000. Georgina was buried, as directed in her will, at the church of the Blessed Mary and St Nicholas in Etchingham, Sussex. She is in an unmarked grave to the right of that of her former employer, Professor Ubbelohde, placed there at her request. "Georgina Greene is remembered in Etchingham for her very generous donation to the Church ... It allowed us to redecorate the interior of our beautiful Grade I listed building".
Ubbelohde Fund
The Fund (more properly, the Ubbelohde Bequest) was left to the Company by Professor Ubbelohde under his will. The Bequest was itself registered as a separate charity in December 1995, with the Mercers’ Company as corporate trustee. The charity number was 1051484 and was for the advancement of secondary education in England and in particular for the benefit of St Paul’s School. Grants to St Paul’s School were paid regularly through the 1990s and early 2000s. In 2016 the charity’s assets were transferred to St Paul’s School.
Memorial Service
A memorial service for Professor Paul Ubbelohde was held at the Church of the Immaculate Conception, Farm Street on 24 May 1988. A message from Pope John Paul II was read by Georgina Greene. For several years afterwards, on his birthday, she published in The Times a message remembering him.
Among the many distinguished guests attending the service were the Comte and Comtesse Armand de Malherbe. The Comtesse was formerly Angela, daughter of Alberto Julio Ubbelohde, brother of Paul, who lived in the United States. Angela, whose home was in New Canaan, married the Comte in Marçon, Sarthe on 30 June 1956. Another daughter, Marie Thérèse Ubbelohde (Vicomtesse Ogier d’Ivry), and her husband also attended.
References
1907 births
1988 deaths
People educated at St Paul's School, London
Alumni of Christ Church, Oxford
Alumni of Queen's University Belfast
Academics of Queen's University Belfast
Thermodynamicists
British physical chemists
Fellows of the Royal Society
Members of the Pontifical Academy of Sciences
Commanders of the Order of the British Empire | Alfred Ubbelohde | [
"Physics",
"Chemistry"
] | 2,062 | [
"Thermodynamics",
"Thermodynamicists"
] |
42,797,019 | https://en.wikipedia.org/wiki/Optical%20phenomenon | Optical phenomena are any observable events that result from the interaction of light and matter.
All optical phenomena coincide with quantum phenomena. Common optical phenomena are often due to the interaction of light from the Sun or Moon with the atmosphere, clouds, water, dust, and other particulates. One common example is the rainbow, when light from the Sun is reflected and refracted by water droplets. Some phenomena, such as the green ray, are so rare they are sometimes thought to be mythical. Others, such as Fata Morganas, are commonplace in favored locations.
Other phenomena are simply interesting aspects of optics, or optical effects. For instance, the colors generated by a prism are often shown in classrooms.
Scope
Optical phenomena encompass a broad range of events, including those caused by atmospheric optical properties, other natural occurrences, man-made effects, and interactions involving human vision (entoptic phenomena). Also listed here are unexplained phenomena that could have an optical explanation and "optical illusions" for which optical explanations have been excluded.
There are many phenomena that result from either the particle or the wave nature of light. Some are quite subtle and observable only by precise measurement using scientific instruments. A famous example is the bending of starlight by the Sun during a solar eclipse, a phenomenon that serves as evidence for the curvature of space as predicted by the theory of relativity.
Atmospheric optics
Non-atmospheric optical phenomena
Dichromatism
Gegenschein
Iridescence
Opposition effect
Shadow
Shade
Silhouette
Sylvanshine
Zodiacal light
Other optical effects
Asterism, star gems such as star sapphire or star ruby
Aura, a phenomenon in which gas or dust surrounding an object luminesces or reflects light from the object
Aventurescence, also called the Schiller effect, spangled gems such as aventurine quartz and sunstone
Baily's beads, grains of sunlight visible in total solar eclipses.
camera obscura
Cathodoluminescence
Caustics
Chatoyancy, cat's eye gems such as chrysoberyl cat's eye or aquamarine cat's eye
Chromatic polarization
Diffraction, the apparent bending and spreading of light waves when they meet an obstruction
Dispersion
Double refraction or birefringence of calcite and other minerals
Double-slit experiment
Electroluminescence
Evanescent wave
Fluorescence, also called luminescence or photoluminescence
Mie scattering (Why clouds are white)
Metamerism as of alexandrite
Moiré pattern
Newton's rings
Phosphorescence
Pleochroism gems or crystals, which seem "many-colored"
Rayleigh scattering (Why the sky is blue, sunsets are red, and associated phenomena)
Reflection
Refraction
Sonoluminescence
Shrimpoluminescence
Synchrotron radiation
The separation of light into colors by a prism
Triboluminescence
Thomson scattering
Total internal reflection
Twisted light
Umov effect
Zeeman effect
The ability of light to travel through space or through a vacuum.
Entoptic phenomena
Diffraction of light through the eyelashes
Haidinger's brush
Monocular diplopia (or polyplopia) from reflections at boundaries between the various ocular media
Phosphenes from stimulation other than by light (e.g., mechanical, electrical) of the rod cells and cones of the eye or of other neurons of the visual system
Purkinje images.
Optical illusions
The unusually large size of the Moon as it rises and sets, the Moon illusion
The shape of the sky, the sky bowl
Unexplained phenomena
Some phenomena are yet to be conclusively explained and may possibly be some form of optical phenomena. Some consider many of these "mysteries" to simply be local tourist attractions that are not worthy of thorough investigation.
Hessdalen lights
Min Min lights
Light of Saratoga
Naga fireballs
See also
List of optical topics
Optics
References
Source
Further reading
Thomas D. Rossing and Christopher J. Chiaverina, Light Science: Physics and the Visual Arts, Springer, New York, 1999, hardback,
Robert Greenler, Rainbows, Halos, and Glories, Elton-Wolf Publishing, 1999, hardback,
Polarized Light in Nature, G. P. Können, Translated by G. A. Beerling, Cambridge University Press, 1985, hardcover,
M.G.J. Minnaert, Light and Color in the Outdoors,
John Naylor "Out of the Blue: A 24-hour Skywatcher's Guide", CUP, 2002,
Abenteuer im Erdschatten (German).
The Marine Observers' Log
External links
Atmospheric Optics Reference site
is:Ljósfræðilegt fyrirbrigði | Optical phenomenon | [
"Physics"
] | 967 | [
"Optical phenomena",
"Physical phenomena"
] |
42,797,118 | https://en.wikipedia.org/wiki/Sulfonamide | In organic chemistry, the sulfonamide functional group (also spelled sulphonamide) is an organosulfur group with the structure . It consists of a sulfonyl group () connected to an amine group (). Relatively speaking this group is unreactive. Because of the rigidity of the functional group, sulfonamides are typically crystalline; for this reason, the formation of a sulfonamide is a classic method to convert an amine into a crystalline derivative which can be identified by its melting point. Many important drugs contain the sulfonamide group.
A sulfonamide (compound) is a chemical compound that contains this group. The general formula is or , where each R is some organic group; for example, "methanesulfonamide" (where R = methane, R' = R" = hydrogen) is . Any sulfonamide can be considered as derived from a sulfonic acid by replacing a hydroxyl group () with an amine group.
In medicine, the term "sulfonamide" is sometimes used as a synonym for sulfa drug, a derivative or variation of sulfanilamide. The first sulfonamide was discovered in Germany in 1932.
Synthesis and reactions
Sulfonamides can be prepared in the laboratory in many ways. The classic approach entails the reaction of sulfonyl chlorides with an amine.
A base such as pyridine is typically added to absorb the HCl that is generated. Illustrative is the synthesis of sulfonylmethylamide.
The reaction of primary and secondary amines with benzenesulfonyl chloride is the basis of the Hinsberg reaction, a method for detecting primary and secondary amines.
Sulfonamides undergo a variety of acid-base reactions. The N-H bond can be deprotonated. The alkylsulfonamides can be deprotonated at carbon. Arylsulfonamides undergo ortho-lithiation.
Sultams
Sultams are cyclic sulfonamides. Bioactive sultams include the antiinflammatory ampiroxicam and the anticonvulsant sulthiame. Sultams are prepared analogously to other sulfonamides, allowing for the fact that sulfonic acids are deprotonated by amines. They are often prepared by one-pot oxidation of disulfides or thiols linked to amines. An alternative synthesis of sultams involves initial preparation of a linear sulfonamide, followed by intramolecular C-C bond formation (i.e. cyclization), a strategy that was used in the synthesis of a sultam-based deep-blue emitter for organic electronics.
Sulfinamides
The related sulfinamides (R(S=O)NHR) are amides of sulfinic acids (R(S=O)OH) (see sulfinyl). Chiral sulfinamides such as tert-butanesulfinamide, p-toluenesulfinamide and 2,4,6-trimethylbenzenesulfinamide are relevant to asymmetric synthesis.
Disulfonimides
Bis(trifluoromethanesulfonyl)aniline is a source of the triflyl () group.
The disulfonimides are of the type with two sulfonyl groups flanking an amine. As with sulfinamides, this class of compounds is used as catalysts in enantioselective synthesis.
See also
Sulfamic acid
Sulfamide
References
Functional groups | Sulfonamide | [
"Chemistry"
] | 765 | [
"Functional groups"
] |
42,797,521 | https://en.wikipedia.org/wiki/Pi%20%28film%29 | Pi (stylized as ) is a 1998 American conceptual psychological thriller film written and directed by Darren Aronofsky (in his feature directorial debut). Pi was filmed on high-contrast black-and-white reversal film. The title refers to the mathematical constant pi. The story focuses on a mathematician with an obsession to find underlying complete order in the real world and contrasting two seemingly irreconcilable entities: the imperfect irrationality of humanity and the rigor and regularity of mathematics, specifically number theory. The film explores themes of religion, mysticism, and the relationship of the universe to mathematics.
The film received positive reviews and earned Aronofsky the Directing Award at the 1998 Sundance Film Festival, the Independent Spirit Award for Best First Screenplay and the Gotham Open Palm Award.
Plot
Unemployed number theorist Max Cohen, who lives in a drab apartment in Chinatown, Manhattan, believes everything in nature can be understood through numbers. He suffers from cluster headaches, extreme paranoia, hallucinations, and schizoid personality disorder. His only social interactions are with his mathematics mentor, Sol Robeson (now disabled from a stroke), and those who live in his building: Jenna, a little girl fascinated by his ability to perform complex calculations, and Devi, a young woman living next door who sometimes speaks with him.
Max tries to program his computer, named Euclid (after the geometer), to make stock predictions. Euclid malfunctions, printing out a seemingly random 216-digit number, as well as a single stock pick at one-tenth its current value, then crashes. Disgusted, Max throws away the printout. The next morning, he learns that Euclid's pick was accurate but cannot find the printout. When Max mentions the number, Sol becomes unnerved and asks if it contained 216 digits, revealing that he came across the same number years ago. He urges Max to take a break from his work.
Max meets Lenny Meyer, a Hasidic Jew who does mathematical research on the Torah. Lenny demonstrates some simple Gematria, the correspondence of the Hebrew alphabet to numbers, and explains that some people believe the Torah is a string of numbers forming a code sent by God. Intrigued, Max notes some of the concepts parallel other mathematical concepts, such as the Fibonacci sequence. Agents of a Wall Street firm approach Max. One of them, Marcy Dawson, offers him a classified computer chip called "Ming Mecca" in exchange for the results of his work.
Using the chip, Max has Euclid analyze mathematical patterns in the Torah. Once again, Euclid displays the 216-digit number before crashing. As Max writes down the number, he realizes that he knows the pattern, undergoes an epiphany, and loses consciousness. After waking up, Max appears to become clairvoyant and visualizes the stock market patterns he sought. His headaches intensify, and he discovers a vein-like bulge protruding from his right temple. Max has a falling out with Sol after Sol urges him to quit his work.
Dawson and her agents grab Max on the street and try to force him to explain the number, having found the printout Max threw away. Attempting to use the number to manipulate the stock market, the firm instead caused the market to crash. Driving by, Lenny rescues Max, but takes him to his companions at a nearby synagogue. They ask Max to give them the 216-digit number, believing it was meant for them to bring about the messianic age, as the number represents the unspeakable name of God. Max refuses, insisting the number has been revealed to him alone.
Max flees and visits Sol, only to learn from his daughter, Jenny, that he died from another stroke. He finds a piece of paper with the number in his study. At his own apartment, Max experiences another headache but does not take his painkillers. Believing the number and the headaches are linked, Max tries to concentrate on the number through his pain. After passing out, Max goes to the bathroom where he stares at himself in the mirror before lighting a match and burning the piece of paper with the number. Max then takes a power drill to his own head, trepanning himself in an effort to find relief.
Sometime later, Jenna approaches Max in a park and asks him to do several calculations, including 748 ÷ 238 (an approximation for pi). Max smiles and says that he does not know the answer, seemingly at peace.
Cast
Sean Gullette as Maximillian "Max" Cohen
Mark Margolis as Sol Robeson
Ben Shenkman as Lenny Meyer
Samia Shoaib as Devi
Pamela Hart as Marcy Dawson
Stephen Pearlman as Rabbi Cohen
Ajay Naidu as Farouq
Kristyn Mae-Anne Lao as Jenna
Lauren Fox as Jenny Robeson
Clint Mansell as Photographer
Production
Before production, to finance the complex visual sets and shots for the film, producer Eric Watson and director Darren Aronofsky asked every friend, relative, or acquaintance for donations of $100 each. Eventually, they accumulated about $60,000 for their production budget.
The film was shot on an Aaton XTR Prod Camera, which shoots with 16mm film, with a Bolex H16 Camera used for most of the handheld shots that the crew broke and had to fix. A Canon 16mm camera package was also used. Lenses were from Angenieux. The film was shot on black and white reversal film stock; Aronofsky aimed for high-contrast shots to give Pi a more "technically raw and spontaneous" look.
Pi was produced with a low budget, with the crew being paid $200 a day and actors being paid $75 a day. To save money, various cost-cutting techniques were used, including using only the actors' clothes and thrift store purchases as costumes, and shooting all of the subway and outdoor city scenes illegally to get around paying expensive permits. To get vehicles for the film, Aronofsky says he "probably" rented a station wagon belonging to the film's consulting producer, and claims to have hailed a cab and paid the driver $100 to keep his car there for a scene that was later cut, rather than renting out an additional vehicle.
For the main set, which was Max Cohen's apartment, Scott Vogel secured a section of his fathers's warehouse in Bushwick, Brooklyn. A back room was cleared out and used as a sound stage, where Max's Euclid computer was built and the majority of the film was shot.
Finishing the film was more costly than shooting it. The post-budget was $68,183, most of which went into post-production sound, film and lab work, and film editing. Throughout the filming, 53,000 feet of 16mm film was shot, amounting to about 23 hours over 28 days.
The film was sent to be developed in Bono Labs in Arlington, Virginia, which was the only lab capable of developing black and white reversal stock. Consequently, the crew only received dailies a week after sending the footage in. Raw stock cost $5,414 and developing it cost $18,000. During post-production, most of the budget went toward the negative cut, which was a match back from an AVID cut list. Clint Mansell created the score on his equipment, for which he was paid a deferred fee.
The production cost was $60,927, with post-production costing an additional $68,183. Along with other expenses, including insurance, the film cost $134,815.
Themes
Mathematics
Pi features multiple references to mathematics and mathematical theories. For instance, Max finds the golden spiral occurring everywhere, including the stock market. Max's belief that diverse systems embodying nonlinear dynamics share a unifying pattern has some similarity to results in chaos theory, which provides a means for describing certain phenomena of nonlinear systems, which might be thought of as patterns. During the climactic final scene, a pattern resembling a bifurcation diagram is apparent on Max's shattered mirror.
The game of Go
In the film, Max periodically plays Go with his mentor, Sol. This game has historically stimulated the study of mathematics and features a simple set of rules that results in a complex game strategy. Each character uses the game as a model for their view of the universe: Sol says that the game is a microcosm of an extremely complex and chaotic world, while Max asserts its complexity gradually converges toward patterns that can be found.
Gullette and Margolis spent many hours learning the game at the Brooklyn Go Club and received help from Dan Weiner, one of three Go consultants credited to the film. Barbara Calhoun and Michael Solomon also served as game consultants.
Kabbalah
Early in the film, when Lenny speaks with Max about his work, he asks if Max is familiar with kabbalah. The numerological interpretation of the Torah and the 216-letter name of God, known as the Shem HaMephorash, are important concepts in traditional Jewish mysticism.
Quran
Another religious reference comes while Max is at the market looking for that day's newspaper, when a recitation citing Quran 2:140 can be heard in the background: "Or do you say that Abraham and Ishmael and Isaac and Jacob and the Descendants were Jews or Christians? Say, 'Are you more knowing or is Allah?' And who is more unjust than one who conceals a testimony he has from Allah? And Allah is not unaware of what you do."
Soundtrack
Pi launched the film scoring career of Clint Mansell. The soundtrack was released on July 21, 1998, via Thrive Records. AllMusic rated it 4.5 stars out of 5. A music video for "πr²", using an alternative mix of the title track, is available as a special feature on DVD, consisting of footage from the film intercut with stock color reels of ants, referencing one of the film's visual motifs.
Credits
Design – Jeremy Dawson, Sneak Attack
Executive-Producer – Eric Watson, Ricardo Vinas, Sioux Zimmerman
Mastered By – Mark Fellows
Written-By [Voiceover] – Darren Aronofsky, Sean Gullette
Release
More than a decade after its theatrical release, the rights to the film reverted from Lionsgate (owner of Summit Entertainment and the Artisan library) back to Aronofsky, who sold it to A24 in 2023. The 8K and Atmos restoration version was released on March 14 by A24 in the IMAX format, to commemorate its 25th anniversary.
Box office
Produced on a budget of $134,815, the film was financially successful at the box office, grossing $3,221,152 in the United States despite only a limited theatrical release. It sold steadily on DVD, and was the first film ever to be sold as a download on the Internet. Through the website Sightsound.com, the film was available for streaming in a pay-per-view window.
Critical response
Pi was received well by critics upon release. On Rotten Tomatoes, the film has an 88% approval rating based on 59 reviews with an average rating of 7.4/10. The website's critical consensus reads: "Dramatically gripping and frighteningly smart, this Lynchian thriller does wonders with its unlikely subject and shoestring budget." On Metacritic, the film has a rating of 72 out of 100 based on 23 reviews, indicating "generally favorable reviews".
Roger Ebert gave the film three and a half out of four stars, writing: "Pi is a thriller. I am not very thrilled these days by whether the bad guys will get shot or the chase scene will end one way instead of another. You have to make a movie like that pretty skillfully before I care. But I am thrilled when a man risks his mind in the pursuit of a dangerous obsession."
James Berardinelli gave the film three out of four stars, writing: "Pi transports us to a world that is like yet unlike our own, and, in its mysterious familiarity, is eerie, intense, and compelling. Reality is a fragile commodity, but, because the script is well-written and the central character is strongly developed, it's not hard to suspend disbelief....It probably deserves 3.1416 stars, but since my scale doesn't support that, I'll round it off to three."
See also
List of cult films
List of films about mathematicians
List of films featuring surveillance
Notes
References
External links
Pi: Faith in Numbers - Brows Held High on YouTube
1998 films
1998 directorial debut films
1998 independent films
1990s avant-garde and experimental films
1990s English-language films
1998 psychological thriller films
American avant-garde and experimental films
American black-and-white films
American independent films
American psychological thriller films
American neo-noir films
Artisan Entertainment films
Fiction with unreliable narrators
Films about Jews and Judaism
Films about mathematics
Films directed by Darren Aronofsky
Films scored by Clint Mansell
Films set in Manhattan
Films shot in New York City
Films with screenplays by Darren Aronofsky
Hebrew-language films
Names of God in literature and fiction
A24 (company) films
Protozoa Pictures films
Sundance Film Festival award–winning films
Films shot in 16 mm film
IMAX films
Pi
1990s American films
English-language independent films
English-language thriller films | Pi (film) | [
"Mathematics"
] | 2,727 | [
"Pi"
] |
42,797,731 | https://en.wikipedia.org/wiki/Cruciger%20lignatilis | Cruciger lignatilis is an anamorph species of fungus, found growing on rotting wood in Germany. It is the only species in the genus Cruciger in the class Agaricomycetes. It has not yet been placed in any order or family. The genus name refers to the cruciform (cross-shaped) conidia.
References
External links
Agaricomycetes
Fungi of Europe
Taxa named by Franz Oberwinkler
Fungus species | Cruciger lignatilis | [
"Biology"
] | 97 | [
"Fungi",
"Fungus species"
] |
54,273,558 | https://en.wikipedia.org/wiki/Isoserine | Isoserine is a non-proteinogenic α-hydroxy-β-amino acid, and an isomer of serine. Non-proteinogenic amino are not part of the genetic code of any known organism and are only present in proteins if added post-translationally. Isoserine has only been produced synthetically.
The first documented synthesis of isoserine in a laboratory setting was by Miyazawa et al., who published their results in 1976.
See also
Abiogenesis
Miller–Urey experiment
References
Non-proteinogenic amino acids
Alpha hydroxy acids
Beta-Amino acids | Isoserine | [
"Chemistry",
"Biology"
] | 121 | [
"Biochemistry stubs",
"Biotechnology stubs",
"Biochemistry"
] |
54,274,216 | https://en.wikipedia.org/wiki/Moduli%20stack%20of%20vector%20bundles | In algebraic geometry, the moduli stack of rank-n vector bundles Vectn is the stack parametrizing vector bundles (or locally free sheaves) of rank n over some reasonable spaces.
It is a smooth algebraic stack of the negative dimension . Moreover, viewing a rank-n vector bundle as a principal -bundle, Vectn is isomorphic to the classifying stack
Definition
For the base category, let C be the category of schemes of finite type over a fixed field k. Then is the category where
an object is a pair of a scheme U in C and a rank-n vector bundle E over U
a morphism consists of in C and a bundle-isomorphism .
Let be the forgetful functor. Via p, is a prestack over C. That it is a stack over C is precisely the statement "vector bundles have the descent property". Note that each fiber over U is the category of rank-n vector bundles over U where every morphism is an isomorphism (i.e., each fiber of p is a groupoid).
See also
classifying stack
moduli stack of principal bundles
References
Algebraic geometry | Moduli stack of vector bundles | [
"Mathematics"
] | 238 | [
"Fields of abstract algebra",
"Algebraic geometry"
] |
54,275,492 | https://en.wikipedia.org/wiki/Carpenter%20v.%20United%20States | Carpenter v. United States, , is a landmark United States Supreme Court case concerning the privacy of historical cell site location information (CSLI). The Court held that government entities violate the Fourth Amendment to the United States Constitution when accessing historical CSLI records containing the physical locations of cellphones without a search warrant.
Prior to Carpenter, government entities could obtain cellphone location records from service providers by claiming the information was required as part of an investigation, without a warrant, but the ruling changed this procedure. Recognizing the influence of new consumer communications devices in the 2010s, the Court expanded its conceptions of constitutional rights toward the privacy of this type of data. However, the Court emphasized that the Carpenter ruling was narrowly restricted to the precise types of information and search procedures that were relevant to this case.
Background
Cell site location information (CSLI)
Cellular telephone service providers are able to find the location of cell phones through either global positioning system (GPS) data or cell site location information (CSLI), in the process of connecting calls and data transmissions. CSLI is captured by nearby cell towers, and this information is used to triangulate the location of phones. Service providers capture and store this data for business purposes, such as troubleshooting, maximizing network efficiencies, and determining whether to charge customers roaming fees for particular calls.
The data can also illustrate the historical movements of a cellphone. Thus, anyone with access to this data has the ability to know where the phone has been and what other cell phones were in the same area at a given time. When users travel with their cellphones, this data can theoretically illustrate every place a person has traveled, and possibly the locations of other people encountered via their corresponding data.
Third-party doctrine
Prior to Carpenter, the Supreme Court consistently held that a person had no reasonable expectation of privacy in regard to information voluntarily turned over to third-parties such as telephone companies, and therefore a search warrant is not required when government officials seek this information. This legal theory is known as the third-party doctrine, established by the Supreme Court in Smith v. Maryland (1979), in which the Court determined that government can obtain a list of phone numbers dialed from a suspect's phone.
By the 2010s, cellphones and particularly smartphones had become important tools for nearly every person in the United States. Many applications, such as GPS navigation and location tools, require a phone to send and receive information constantly, including the exact location of the phone, often without an affirmative action on the part of its owner. As technology advanced in the 2010s, the Supreme Court began to modify its precedents on government searches of personal communications devices, given new consumer behaviors that may transcend the third-party doctrine.
Background
Between December 2010 and March 2011, several individuals in the Detroit, Michigan area conspired and participated in armed robberies at RadioShack and T-Mobile stores across the region. In April 2011, four of the robbers were captured and arrested. The petitioner, Timothy Carpenter, was not among the initial group of arrestees. One of those arrested confessed and turned over his phone so that FBI agents could review the calls made from his phone around the time of the robberies. The agents obtained a search warrant to inspect the information in that arrestee's phone, in order to find additional contacts of the arrestee and compile more evidence about the crime ring.
From the historical cell site records on the arrestee's phone, the agents confirmed that Timothy Carpenter was also part of the crime ring, and proceeded to compile information about the location of his phone over 127 days. In turn, this information revealed that Carpenter had been within a two-mile radius of four robberies at the times they were perpetrated. This evidence was used to support Carpenter's arrest. At criminal court, Carpenter was found guilty of several counts of aiding and abetting robberies that affected interstate commerce, and another count of using a firearm during a violent crime. He was sentenced to 116 years in prison.
Appeal at the Sixth Circuit
Carpenter appealed his conviction and sentence to the United States Court of Appeals for the Sixth Circuit, arguing that the CSLI evidence used against him should be suppressed because the police had not obtained a warrant pertaining to his CSLI records before searching through them. In 2015, the Circuit Court upheld Carpenter's conviction. This ruling was largely based on the Smith v. Maryland precedent, stating that Carpenter used cellular telephone networks voluntarily, and per the third-party doctrine he had no reasonable expectation that the data should be private. Thus, review of that information by the police did not constitute a "search" and did not require a warrant under the Fourth Amendment.
Carpenter appealed this ruling to the U.S. Supreme Court, which granted certiorari in 2016.
Supreme Court
Twenty amicus curiae briefs were filed by interested organizations, scholars, and corporations for Carpenter's case. Some considered the case to be the most important Fourth Amendment dispute to come before the Supreme Court in a generation. The Court issued its decision in 2018, with the majority opinion written by Chief Justice John Roberts.
The Court's ruling recognized that the Carpenter case revealed a contradiction between two lines of Supreme Court rulings on the matter of police searches of personal communications information. In United States v. Jones (2012) the Court had ruled that GPS tracking could constitute a search under the Fourth Amendment as a violation of a person's reasonable expectation of privacy. Meanwhile, the Court had held in Smith v. Maryland (1979) that the third-party doctrine absolved the government from warrant requirements when searching through telephone records.
Ultimately, in Carpenter the court determined that the third-party doctrine could not be extended to historical cell site location information (CSLI). Instead, the Court compared "detailed, encyclopedic, and effortlessly compiled" CSLI records to the GPS information at issue in United States v. Jones, recognizing that both forms of data accord the government the ability to track individuals' past movements. Furthermore, the Court noted that CSLI could pose even greater privacy risks than GPS data, as the prevalence of cellphones could accord the government "near perfect surveillance" of an individual's movements. Accordingly, the Court ruled that, under the Fourth Amendment, the government must obtain a search warrant in order to access historical CSLI records. Roberts argued that technology "has afforded law enforcement a powerful new tool to carry out its important responsibilities. At the same time, this tool risks Government encroachment of the sort the Framers [of the U.S. Constitution], after consulting the lessons of history, drafted the Fourth Amendment to prevent." As stated in the opinion, "Unlike the nosy neighbor who keeps an eye on comings and goings, they [new technologies] are ever alert, and their memory is nearly infallible. There is a world of difference between the limited types of personal information addressed in Smith [...] and the exhaustive chronicle of location information casually collected by wireless carriers today."
However, Roberts stressed that the Carpenter decision was a very narrow one and did not affect other uses of the third-party doctrine, such as searches of banking records. Similarly, he noted that the decision did not prevent the collection of CSLI without a warrant in cases of emergency or for issues of national security.
Dissenting opinions
Justice Anthony Kennedy, in a dissenting opinion, cautioned against the limitations on law enforcement inherent in the majority opinion. According to Kennedy, the ruling "places undue restrictions on the lawful and necessary enforcement powers exercised not only by the Federal Government, but also by law enforcement in every State and locality throughout the Nation. Adherence to this Court's longstanding precedents and analytic framework would have been the proper and prudent way to resolve this case."
In another dissent, Justice Samuel Alito wrote: "I fear that today's decision will do far more harm than good. The Court's reasoning fractures two fundamental pillars of Fourth Amendment law, and in doing so, it guarantees a blizzard of litigation while threatening many legitimate and valuable investigative practices upon which law enforcement has rightfully come to rely." In yet another dissent, Justice Neil Gorsuch agreed with most of the majority opinion but stressed that CSLI data is personal property, and its storage by telephone companies should be immaterial. According to Gorsuch, the Fourth Amendment "grants you the right to invoke its guarantees whenever one of your protected things (your person, your house, your papers, or your effects) is unreasonably searched or seized. Period." Gorsuch further recommended that the third-party doctrine be overturned as inconsistent with the original meaning of the Fourth Amendment.
Impact and subsequent developments
After the Supreme Court ruling, Carpenter's criminal conviction was remanded to the Sixth Circuit to determine if it could stand without the CSLI data that required a warrant per the Supreme Court. Carpenter's lawyers argued that the data should have been subject to the exclusionary rule and thrown out as material collected without a proper warrant under the Supreme Court's ruling. However, the Circuit Court judges concluded that the FBI was acting in good faith with respect to collecting the data based on the law at the time the crimes were committed. This type of good faith exemption is permitted per another Supreme Court precedent, Davis v. United States (2011). The evidence was allowed to stand, and the Sixth Circuit again upheld Carpenter's criminal conviction and prison sentence. His arguments concerning sentencing procedures under the recently enacted First Step Act were rejected.
The Supreme Court's ruling in Carpenter was narrow and did not otherwise change the third-party doctrine related to other business records that might incidentally reveal location information, nor did it overrule prior decisions concerning conventional surveillance techniques and tools such as security cameras. The Court did not extend its ruling to other matters related to cellphones not presented in Carpenter, including real-time CSLI or "tower dumps" (the downloading of information about all the devices that were connected to a particular cell site during a particular interval). The opinion also did not consider other data collection goals involving foreign affairs or national security.
References
Further reading
External links
Case page at SCOTUSblog
2016 in United States case law
2018 in United States case law
United States Supreme Court cases
United States Fourth Amendment case law
United States Supreme Court cases of the Roberts Court
United States Court of Appeals for the Sixth Circuit cases
Search and seizure case law
Telecommunications case law
Mobile phone culture
2010s in Detroit
Global Positioning System | Carpenter v. United States | [
"Technology",
"Engineering"
] | 2,143 | [
"Global Positioning System",
"Aerospace engineering",
"Wireless locating",
"Aircraft instruments"
] |
54,277,050 | https://en.wikipedia.org/wiki/Radio-86RK | The Radio-86RK () is a build-it-yourself home computer designed in the Soviet Union. It was featured in the popular Radio () magazine for radio hams and electronics hobbyists in 1986. The letters RK in the title stands for the words Radio ham's Computer (). Design of the computer was published in a series of articles describing its logical structure, electrical circuitry, drawings of printed circuit boards and firmware. The computer could be built entirely out of standard off-the-shelf parts. Later it was also available in a kit form as well as fully assembled form.
Predecessors
The Radio-86RK is the successor of earlier build-it-yourself computer of the same designers, the Micro-80, and has limited compatibility with it. Its description was also published in a series of articles in the Radio magazine in the early 1980s. But its complex design, consisting of several modules and containing about 200 chips, lack of printed circuit board drawings and most importantly lack of chips on sale made the assembly of the computer hard to accomplish. Micro-80 computers were assembled by only a few enthusiasts.
Assembly process
To assemble the computer, it was required to acquire the necessary electronic components, to make two printed circuit boards and mount all components on them. It was mostly a single board computer, as the second board served only as the base to mount the keyboard keys. The main board used a single large connector for power, keyboard, tape recorder and even video output. Hence it was easy to disconnect the board and work on both sides of it outside the case.
Next, the firmware has to be written in two erasable ROM chips using a chip programmer. Also a power supply unit, a keyboard and a computer case were to be made. The computer used a normal domestic TV set connected to a composite video input as a display. As most Soviet TVs of the time did not have video inputs, it was necessary to install a special module or modify the TV's electronics to implement it. The approximate cost of all required components was about 260 rubles.
The circuitry of the Radio-86RK contains only 29 chips and was relatively easy to assemble. However, finding the chips to buy was difficult, as they were scarce and sold in small volumes in major cities of the USSR. It was particularly difficult to find the KR580VG75 video chip, which was produced only in small quantities. This led to the development of a replacement video circuit which contained 19 chips on a separate board, and was similar to the display module of the Micro-80 computer.
The editorial board of Radio magazine received a large amount of mail in response to the publication. In almost every letter, readers noted how difficult it was to find the necessary electronic components. The editorial board published an appeal to the Soviet electronics industry, proposing they begin producing Radio-86RK kits commercially. By the end of the 1980s manufacturing of computer cases, keyboards and main boards for the Radio-86RK, as well as selling electronic components were carried out by numerous cooperatives.
Technical specifications
CPU: KR580VM80A (Intel 8080A clone, until mid-1983 was designated as KR580IK80A) clocked at 1.777 MHz. For simplicity's sake the clock generator KR580GF24 (Intel 8224 clone) is used both for CPU and video controller. As 16 MHz clock generator frequency is chosen to generate television compatible signal, the CPU is unable to run at its maximum speed of 2.5 MHz.
RAM: 16 KiB in original version, using K565RU3A chips (4116 clone). It is possible to double memory size by mounting additional RAM chips on top of the chips installed on the main board.
ROM: 2 KiB erasable ROM of type K573RF5 (2716 clone), contains monitor firmware
Video controller: KR580VG75 programmable CRT controller, interfaced with KR580VT57 (Intel 8257 clone) DMA controller. The DMA controller is also used for dynamic memory refresh. Video controller KR580VG75 is a clone of Intel 8275, a rare chip not used in any mainstream system, and originally proposed for terminals.
Text mode: 64 x 25 characters, monochrome. Images for the upper case Cyrillic and Latin characters in KOI-7 N2 encoding are stored in the KR573RF1 (2708 clone) erasable ROM.
Semigraphics: 2 x 2 dot matrix combinations in the graphic character subset – 128 x 50 dots total. Higher resolutions are available by appropriate video controller programming.
Keyboard: 66 keys. The keyboard matrix is attached via programmable peripheral interface chip KR580VV55 (Intel 8255 clone) and scanned by CPU.
Sound: CPU pin INTE used as a sound source. This pin is usually used to interface with programmable interrupt controller, but since the computer did not have any interrupt sources, the pin was used for sound generation. CPU commands EI and DI allowed switching the pin state.
Storage media: cassette tape. With DMA controller turned on the CPU is unable to measure time intervals precisely, that is required for tape reading and recording. Therefore, during tape operations, the DMA controller turns off. This results in stopping the video controller and memory refresh, so the CPU performs memory refresh programmatically. Signal from recorder is amplified by the К140УД6 (analog of MC1456), negative part is cut away by diode and then the signal is fed to the dedicated TTL input of the same KR580VV55 that serves the keyboard.
Recording format: 0 was written as a pair of values 0,1 and 1 was written as 1,0. Hence the overall signal had no constant component and could be stored within the frequency range supported by the tape recorder. A synchronization byte (E6) was written first to synchronize the reading frame. A simple second layer that featured leading zeroes, offset, length and checksum was implemented on the top.
Additional I/O: The computer also has a slot for the second chip of the same type. This second chip is meant for various specific projects (amateur radio constructions, consumer electronics controllers, sensors, etc). As long as only the keyboard and tape recorder are required, this second chip does not need to be mounted on the circuit board.
Address space: the address space consists of 8 large slots, addressing 8 Kb each. Two or four of them are dedicated for RAM (so 16 or 32 Kb), one for ROM and DMA controller (during write operations, ROM is disconnected from the bus, and data is transferred to the DMA controller; during read operations, DMA controller is disconnected from the bus, and data is transferred from the ROM), one for video controller and two for the interface chips, main and optional. Only RAM actually uses all available addresses, IO devices only use a few cells within they dedicated 8 Kb segment. Separate IO commands that Intel 8080 has are not supported.
Stripboards: to give more creative possibilities for amateurs, the main board has the two small stripboards next to the main connector.
Software
The only software available to the user after turning on the computer is a monitor contained in ROM. The monitor supports basic debugging functions, it allows viewing and modifying memory cells, loading and saving memory contents to the tape, entering and running programs in binary code. The monitor is also HAL: programs that access the hardware only by calling the monitor library support both 16Kb and 32 Kb RAM versions and often also Micro-80 predecessor.
Initially, the Radio magazine distributed programs for the Radio-86RK in the form of hexadecimal dumps. After entering the program dump into the computer's memory, it could be saved to the tape. It was easy to make a mistake when typing in large dumps, so the magazine published checksums along with the dumps. It was necessary to execute "O" monitor directive to calculate the checksum.
The magazine published two versions of the BASIC interpreter: an adapted version of Micro-80 BASIC and a version specially developed for the Radio-86RK featuring enhanced editing capabilities, new functions, and other improvements.
Other software published in the magazine included assembler, debugger, disassembler, text editor, voice recorder, music editing system. Also, a lot of BASIC programs were published, including calculations for electronic circuits design and games.
Another way of obtaining software was the tape exchange among Radio-86RK owners. In 1988, the law on cooperation in the USSR came into force, which made legal to produce software for profit by individuals and cooperatives. From that moment it became possible to buy software for the Radio-86RK.
Operating systems
In 1989 the RAMDOS operating system was developed for the computer. It uses part of computer's RAM as a RAM drive. The contents of RAM drive can be loaded and saved to the tape. The operating system has a minimalistic user interface with only seven commands; it also adds support for file operations to the BASIC interpreter.
In October 1992, the Radio magazine and TOO Lianozovo company announced a floppy-disk controller for the Radio-86RK and the Microsha. The disk operating system (DOS) was stored in erasable ROM on the controller board. The Radio magazine published only the electrical circuitry of the controller but not the firmware. Radio-86RK owners were invited to buy the fully assembled controller or a kit along with two floppy disks containing external DOS commands, programming languages and text description of the operating system.
Industrial made versions
The first industrially produced version of the Radio-86RK was the computer named Microsha (an abbreviation for the words Microcomputer and School). Initially, the authors had given that name to the original computer, but the editorial board has changed the name to Radio-86RK. Eventually, the name Microsha was given to the industrially produced version of Radio-86RK.
Microsha preparation for serial production went in parallel with Radio-86RK articles publication. The changes authors made to the design and firmware made Microsha incompatible with Radio-86RK. In 1989, the Radio magazine had published new firmware for Microsha that improved software compatibility.
Following magazine publication, a number of factories started industrial production of several home computer models using the Radio-86RK design. Not all models were fully compatible with Radio-86RK and included different improvements, such as expanded memory size, additional character sets, rudimentary color support.
The list of models includes:
Alfa-BK
Impulse
Microsha
Electronica KR-01, Electronica KR-02, Electronica KR-03, Electronica KR-04 (electronic kits)
Partner 01.01
Spektr-001
Apogey BK-01
Krista
UMPK-R-32
Sogdiana-1
Mikro-88
Volume of production for a number of models:
Successors
The technical capabilities of the Radio-86RK were very modest. It did not have a graphics mode. The RAM expansion was impossible without serious modifications and loss of compatibility. As the volume of production of home computers was small, and the demand for them kept increasing, the editorial board decided to publish a new design for the build-it-yourself computer.
Although the designers of the Radio-86RK had developed a new 16-bit computer, the Micro-16 (based on the K1810VM86 microprocessor, with a CGA-compatible graphics mode that was capable of running software for the CP/M-86 and MS-DOS), the editorial board again opted for a computer based on the 8-bit processor KR580VM80. The main reason for this was the availability of electronic components for purchase and their cost. The publication of articles on the new computer Orion-128 began in January 1990.
References
External links
Radio-86RK (Russia) The Centre for Computing History.
Radio-86RK emulator written in JavaScript
Software catalog for Radio-86RK
skiselev / radio-86rk — modern redesign of the Radio-86RK as a single board.
Home computers
Soviet computer systems
Computer-related introductions in 1986 | Radio-86RK | [
"Technology"
] | 2,524 | [
"Computer systems",
"Soviet computer systems"
] |
54,277,310 | https://en.wikipedia.org/wiki/Airplane%20scatter | Airplane scattering (or most often reflection) refers to the reflection of a radio signal by the metal structure of a passing aircraft. It is observed on radio waves from high frequency to VHF through to microwaves and, besides back-scattering, yields momentary propagation up to even in mountainous terrain. The most common back-scatter applications are air-traffic radar, bistatic forward-scatter guided-missile and airplane-detecting trip-wire radar, and the US space radar.
It is also a less common propagation mode used by radio amateurs.
History
Airplane scatter itself had been discovered in 1930, but radio amateur usage lagged until the late 80s. The advent of inexpensive SDR based and distributed real time flight tracking enabled precise scheduling, increasing feasibility.
Radio amateur usage
Compared to a single trail of meteor scatter, the time of opening caused by a single airplane is longer it can be from 30 seconds up to a few minutes. Slight asymmetry can sometimes be encountered both in terms of exact timing and the gain of the path.
Range and possible contact lengths are affected by the size of the plane, flight level and the approximate crossing time of the central part of the straight line between the two communicating stations.
Both the onset and decay of the channel is rapid, so to improve success rate, a short contact procedure is used.
Contact opportunities can be predicted based on the precise flight paths of surrounding planes. There exists software for prediction using local (Mode S and ADS-B) or online sources.
Microwave access using high gain antennas needs to consider precise aiming that takes into account elevation angles as well.
See also
Meteor burst communications
Tropospheric scatter
References
External links
http://www.qsl.net/g0isw/g0iswair.htm
Radio frequency propagation | Airplane scatter | [
"Physics"
] | 365 | [
"Physical phenomena",
"Spectrum (physical sciences)",
"Radio frequency propagation",
"Electromagnetic spectrum",
"Waves"
] |
54,277,715 | https://en.wikipedia.org/wiki/Sputnik-1%20EMC/EMI%20lab%20model | Sputnik 1 EMC/EMI is a class of full-scale laboratory models of the Soviet Sputnik 1 satellite, made to test ground Electromagnetic Compatibility (EMC) and Electromagnetic Interference (EMI). The models, manufactured by OKB-1 and NII-885 (headed by Mikhail Ryazansky), were introduced on February 15, 1957.
Sputnik 1 EMC/EMI Lab Model Number 001
The first testing model Sputnik 1 EMC/EMI – Lab model 001, made on February 15, 1957, is located in Deutsches Technikmuseum Berlin, Germany. It comes from the former collections of Russian institute NII-885. The designer of Sputnik Dr. Mikhail Ryazansky was the director back then. In 2007, on the occasion of 50 years since the launch of the first artificial satellite project Sputnik 1, was this first test model exposed to the public in Deutsches Technikmuseum Berlin, Germany.
Sputnik 1 EMC/EMI Lab Models Number 002 and 003
Sequence numbers of other test models Sputnik 1 EMC/EMI Lab model: 002, 003.
Date of production: 1957.
Producer: OKB-1 a NII-885 (the leader of the team: Dr. Mikhail Ryazansky).
On July 20, 2016, a working Sputnik-1 EMC/EMI model, serial number 003, was sold at Bonhams in New York for US$269,000. It featured a still-operational transmitter and four antennas. Of four known Sputnik-1 test articles, this was the only one known to be functional.
Serial numbers 002 a 003 are found in private collections, both models were auctioned off by Bonhams, New York.
Two View Mockups Sputnik 1
Apart from functional laboratory EMC/EMI models 001, 002 and 003 there are two view mockups, which do not contain any active radio or electronics.
Of four known models, two reside in private hands, one is located at the Energia Corporate Museum outside Moscow, and one, lacking internal components, is displayed at the Museum of Flight in Seattle, Washington, US.
References
Sputnik
Electromagnetic compatibility
Prototypes
Physical models | Sputnik-1 EMC/EMI lab model | [
"Physics",
"Engineering"
] | 471 | [
"Radio electronics",
"Electromagnetic compatibility",
"Physical models",
"Physical objects",
"Electrical engineering",
"Matter"
] |
54,278,197 | https://en.wikipedia.org/wiki/VAP%20protein%20family | VAP proteins are conserved integral membrane proteins of the endoplasmic reticulum found in all eukaryotic cells. VAP stands for VAMP-associated protein, where VAMP stands for vesicle-associated membrane protein. Humans have two VAPs that consist of the essential Major Sperm Protein domain and linker plus transmembrane helix to attach to the ER: VAPA and VAPB. A third VAP-like protein is Motile sperm domain containing 2 (MOSPD2), which has all the elements of VAP, and like them binds FFAT motifs, but has at its N-terminus a CRAL-TRIO domain that can bind and transfer lipids.
VAP includes the whole family of protein homologues in all species. For example, baker's yeast expresses two VAPs: Scs2 and Scs22.
References
Protein families
Single-pass transmembrane proteins | VAP protein family | [
"Biology"
] | 190 | [
"Protein families",
"Protein classification"
] |
54,278,396 | https://en.wikipedia.org/wiki/Skeletocutis%20yunnanensis | Skeletocutis yunnanensis is a species of poroid crust fungus in the family Polyporaceae that was described as a new species in 2016. The type specimen was collected in northern Yunnan Province, southwestern China, where it was found growing on decaying angiosperm wood in a temperate forest.
Description
The fungus is characterized by a white, resupinate (crust-like) fruit body with a cream to buff pore surface, and the near absence of a sterile margin when mature. The angular pores number 5–6 per mm with entire mouths. It has a dimitic hyphal structure, containing both generative and skeletal hyphae. The generative hyphae in the subiculum and the trama are covered by fine crystals. The spores are allantoid (sausage-shaped), hyaline, smooth and thin walled, measuring 3.5–4.5 by 1.0–1.2 μm. They typically contain two small oil droplets.
References
Fungi described in 2016
Fungi of China
yunnanensis
Fungus species | Skeletocutis yunnanensis | [
"Biology"
] | 218 | [
"Fungi",
"Fungus species"
] |
54,278,545 | https://en.wikipedia.org/wiki/Skeletocutis%20subodora | Skeletocutis subodora is a species of poroid crust fungus in the family Polyporaceae. It was described as a new species by mycologists Josef Vlasák and Leif Ryvarden in 2012. The type specimen was collected in the Crater Lake visitor's centre in Oregon, United States, where it was growing on a log of Douglas fir. It is named after its similarity to Skeletocutis odora, from which it differs in microscopic characteristics, including its thick subiculum, non-allantoid (sausage-shaped) spores, large cystidioles, and monomitic flesh.
References
Fungi described in 2012
Fungi of the United States
subodora
Taxa named by Leif Ryvarden
Fungi without expected TNC conservation status
Fungus species | Skeletocutis subodora | [
"Biology"
] | 164 | [
"Fungi",
"Fungus species"
] |
54,278,716 | https://en.wikipedia.org/wiki/Ceriporiopsis%20pseudoplacenta | Ceriporiopsis pseudoplacenta is a species of poroid crust fungus in the family Phanerochaetaceae. It was described as a new species by mycologists Josef Vlasák and Leif Ryvarden in 2012. The type specimen was collected in Bogachiel State Park, Washington, where it was found growing on a coniferous log. It is named for its superficial similarity to Postia placenta.
References
Fungi described in 2012
Fungi of the United States
Phanerochaetaceae
Taxa named by Leif Ryvarden
Fungi without expected TNC conservation status
Fungus species | Ceriporiopsis pseudoplacenta | [
"Biology"
] | 124 | [
"Fungi",
"Fungus species"
] |
54,279,431 | https://en.wikipedia.org/wiki/Inverse%20square%20potential | In quantum mechanics, the inverse square potential is a form of a central force potential which has the unusual property of the eigenstates of the corresponding Hamiltonian operator remaining eigenstates in a scaling of all cartesian coordinates by the same constant. Apart from this curious feature, it's by far less important central force problem than that of the Keplerian inverse square force system.
Description
The potential energy function of an inverse square potential is
,
where is some constant and is the Euclidean distance from some central point. If is positive, the potential is attractive and if is negative, the potential is repulsive. The corresponding Hamiltonian operator is
,
where is the mass of the particle moving in the potential.
Properties
The canonical commutation relation of quantum mechanics, , has the property of being invariant in a scaling
, and
,
where is some scaling factor. The momentum and the position are vectors, while the components , and the radius are scalars. In an inverse square potential system, if a wavefunction is an eigenfunction of the Hamiltonian operator , it is also an eigenfunction of the operator , where the scaled operators and are defined as above.
This also means that if a radially symmetric wave function is an eigenfunction of with eigenvalue , then also is an eigenfunction, with eigenvalue . Therefore, the energy spectrum of the system is a continuum of values.
The system with a particle in an inverse square potential with positive (attractive potential) is an example of so-called falling-to-center problem, where there is no lowest energy wavefunction and there are eigenfunctions where the particle is arbitrarily localized in the vicinity of the central point .
See also
Canonical commutation relation
Central force
Scale invariance
References
Quantum mechanics | Inverse square potential | [
"Physics"
] | 372 | [
"Quantum mechanical potentials",
"Quantum mechanics"
] |
54,279,890 | https://en.wikipedia.org/wiki/Hermite%20transform | In mathematics, the Hermite transform is an integral transform named after the mathematician Charles Hermite that uses Hermite polynomials as kernels of the transform.
The Hermite transform of a function is
The inverse Hermite transform is given by
Some Hermite transform pairs
References
Sources
Integral transforms
Mathematical physics | Hermite transform | [
"Physics",
"Mathematics"
] | 59 | [
"Applied mathematics",
"Theoretical physics",
"Mathematical physics"
] |
54,280,856 | https://en.wikipedia.org/wiki/Alexander%20A.%20Clerk | Alexander Adu Clerk, (born 13 May 1947) is a Ghanaian American academic, psychiatrist and sleep medicine specialist who was the Director of the world's first sleep medical clinic, the Stanford Center for Sleep Sciences and Medicine from 1990 to 1998. Clerk is also a Fellow of the American Academy of Sleep Medicine.
Early life and family
Alexander Adu Clerk was born in Cape Coast in the Central Region, Gold Coast in 1947 to Charles Andrew Clerk (c. 1891 – 1977), a civil servant who had done administrative stints in the northern Nigerian cities of Kano and Zaria. C. A. Clerk was also a colporteur of the Hansen Road Seventh-Day Adventist Church in Accra. His mother was Dorothy Esi Mensima Clerk, née Holdbrook, of Cape Coast and Ga Mashie. His paternal grandfather, Charles Emmanuel Clerk (died 14 November 1938) worked in the Gold Coast Civil Service as an interpreter and Secretary to the Governor, and earlier, he was a newspaper publisher in Nigeria. Alexander A. Clerk is a fourth generation descendant of the historically important Clerk family. He is a great-grandson of Alexander Worthy Clerk, a Jamaican Moravian missionary who arrived in the Danish Protectorate of Christiansborg (now the suburb of Osu) in 1843, as part of the original group of 24 West Indian missionaries who worked under the auspices of the Basel Evangelical Missionary Society of Basel, Switzerland. A.W. Clerk was a pioneer of the Presbyterian Church of Ghana and a leader in education in colonial Ghana, co-founding a boarding middle school in Osu, the Salem School in 1843. His paternal great-grandmother, Pauline Hesse (1831–1909) was from the Gold Coast, and of Danish, German and Ga-Dangme heritage. His great-grandaunt was Regina Hesse (1832 –1898), a pioneer educator and school principal who worked with the Basel Mission on the Gold Coast. His granduncle, Nicholas Timothy Clerk (1862 – 1961), a Basel-trained theologian was elected the first Synod Clerk of the Presbyterian Church of the Gold Coast from 1918 to 1932 and a founding father of the all boys’ boarding high school, the Presbyterian Boys’ Secondary School established in 1938.
His uncle, Carl Henry Clerk (1895 – 1982), an educator and Presbyterian minister was elected the fourth Synod Clerk of the Presbyterian Church of the Gold Coast from 1950 to 1954 and served as the Editor of the Christian Messenger newspaper from 1960 to 1963. Another uncle, Theodore S. Clerk (1909 – 1965) was the first Ghanaian architect who planned and developed the harbour metropolis, Tema. A. A. Clerk's aunts were Jane E. Clerk (1904 – 1999), a woman pioneer in education administration and Matilda J. Clerk (1916 – 1984), the second Ghanaian woman to become a physician.
His cousin, Nicholas T. Clerk (1930 – 2012), served as the Rector of the Ghana Institute of Management and Public Administration (GIMPA), the vice-chairman of the Public Services Commission of Ghana and the Chairman of the Public Services Commission of Uganda from 1989 to 1990. Another cousin, George C. Clerk (1931–2019) was a pioneering botanist. Pauline M. Clerk (1935 - 2013), a diplomat and presidential advisor, was also his cousin.
Education and training
A. A. Clerk had his early education at Presbyterian and Seventh-day Adventist schools in Osu and Bekwai in the Greater Accra and Ashanti Regions respectively. After completing his secondary education at Achimota School, he studied medicine at the University of Ghana Medical School, graduating in 1975. He completed a residency in psychiatry at the Loma Linda University School of Medicine. For clinical and fellowship training in sleep medicine, he attended the Stanford University School of Medicine.
Career
Between 1975 and 1978, Clerk was a medical officer at the Effia-Nkwantah Hospital, Sekondi in Ghana's Western Region. Later, he became an assistant professor of psychiatry at the Loma Linda University School of Medicine. He was also an attending physician and was appointed the Chief Director of the Outpatient Psychiatric Clinic and the Mental Hygiene Clinic at the Loma Linda Veteran Administration Hospital from 1984 to 1989. A. A. Clerk was also a consulting psychiatrist with the Riverside County Mental Health Department. Clerk was a clinical assistant professor and later, a clinical associate professor of psychiatry at the Stanford University School of Medicine. He was an attending physician and associate director of the Stanford Sleep Disorders Clinic at Stanford University Medical Center, part of the Stanford Health Care system, rising to become the Director of the world's first sleep medical clinic, the Stanford Center for Sleep Sciences and Medicine from 1990 to 1998 where he was responsible for clinical operations, sleep research and supervised training of other medical specialists. Over the course of his career, he has published numerous scientific articles, book chapters and abstracts pertaining to the science of sleep.
Clerk has done medical outreach work in the United States, Canada, Côte d'Ivoire and his native Ghana. Alexander Clerk is a founding member and Western Region Director of the Ghana Physicians and Surgeons Foundation based in New York City to promote specialist training, professional development in medicine and associated fields in Ghana. He is a member of the Fellowship Training Committee of the American Academy of Sleep Medicine. He has been board certified by the American Board of Sleep Medicine and is a Diplomate of the American Board of Psychiatry and Neurology and a Fellow of the American Academy of Sleep Medicine. Clerk has also been affiliated to the Kaiser Permanente San Jose Medical Center. He served as the Director of Sleep Medicine Services, an affiliate of the O'Connor Health Center based in San Jose, California.
Personal life
Alexander A. Clerk is married to Cynthia V. Clerk (née Oblitey) with three children, Sandra, Andrew and Dorothy.And two grandchildren Chase And Alex Jr. His siblings are the late Major (retired) A. N. Clerk, a military officer; Patrick A. Clerk, a dentist; James S. Clerk, an artist educator and Ellen, a nurse.
Alexander Clerk is the President of the Valley View University Foundation, established to promote academic excellence and scholarship at the Valley View University located in Oyibi, on the Dodowa-Nsawam Road In Ghana. A residential hall at the Valley View University is named Clerk Hall in honour of his family. Clerk also served as the President of the Pacific Ghanaian Adventist Fellowship (PaGAF).
Selected works
Abstracts
Guilleminault, C.; Stoohs, R.; Maistros, P.; Clerk A. (1991) “Idiopathic hypersomnia revisited; the unknown upper airway resistance syndrome.” Sleep Research: 20: 251
Valencia-Flores M.; Bliwise, D.; Guilleminault, C.; Rhodes, N.; Clerk A. (1992) “Gender differences in sleep architecture in apnea syndrome.” Sleep Research: 21: 271
Dantz, B.; Edgar, E.M.; Clerk, A.; Keenan, S.; Seidel W.F.; Dement, W.C. (1992) “Narcoleptics on a 90 minute day: Circadian variations in sleep latencies and tympanic temperature.” Sleep Research: 21: 369
Clerk, A; Duncan, S.; Guilleminault, C. (1992), “Resistance perception during wakefulness in subjects with partial or complete upper airway obstruction during sleep.” Sleep Research: 21: 186
Book chapters
Christian Guilleminault, Riccardo Stoohs, Alex Clerk, Mindy Cetel, Paul Maistros (1993). “The Upper Airway Resistance Syndrome, Sleep Apnea and Rhonchopathy.” Togawa K, Katayama S, Hisihikawa Y, Ohta Y, Horie T (eds.): Basel: Karger, pp. 62–65
Alex Clerk, Vincent Zarcone. (1996) “Impotence: Sleep Clinic Assessment. Treating Sexual Disorders.” Randolph S. Charltoon (ed): Publisher Jossey Bass, San Francisco, CA, Chapter 4, pp. 123–125
Bibliography
Further reading
Journal publications
References
1947 births
Alumni of Achimota School
American Seventh-day Adventists
Clerk family (Ghana)
Ga-Adangbe people
Ghanaian emigrants to the United States
Ghanaian people of Danish descent
Ghanaian people of German descent
Ghanaian people of Jamaican descent
Ghanaian psychiatrists
Ghanaian Protestants
20th-century Ghanaian scientists
Ghanaian Seventh-day Adventists
Seventh-day Adventists in health science
Living people
Loma Linda University alumni
Loma Linda University faculty
People from Accra
Sleep researchers
Stanford University School of Medicine faculty
University of Ghana alumni
University of Ghana Medical School alumni | Alexander A. Clerk | [
"Biology"
] | 1,782 | [
"Sleep researchers",
"Behavior",
"Sleep"
] |
54,280,883 | https://en.wikipedia.org/wiki/NGC%207077 | NGC 7077 is a lenticular blue compact dwarf galaxy located about 56 million light-years away from Earth in the constellation Aquarius. Discovered by astronomer Albert Marth on August 11, 1863, the galaxy lies within the Local Void.
See also
List of NGC objects (7001–7840)
References
External links
Peculiar galaxies
Lenticular galaxies
Aquarius (constellation)
7077
11755
66860
Astronomical objects discovered in 1863
Markarian galaxies | NGC 7077 | [
"Astronomy"
] | 92 | [
"Constellations",
"Aquarius (constellation)"
] |
54,281,184 | https://en.wikipedia.org/wiki/NGC%207020 | NGC 7020 is a barred lenticular galaxy located about 140 million light-years away in the constellation Pavo. NGC 7020 was discovered by astronomer John Herschel on August 31, 1836.
Physical characteristics
NGC 7020 has a large outer ring surrounding a bright inner hexagonal zone containing an inner ring and possibly a bar. The large outer ring is completely detached from the inner hexagonal zone of the galaxy and is dominated by numerous flocculent spiral features. The outer ring has an estimated diameter of . The ring is knotty and bluer than the rest of the galaxy and shows where recent star formation is occurring in NGC 7020. The possible inner ring shows protruding features at the ends of its major axis therefore classifying it as a bar. The galaxy appears to be fairly free of ionized gas, which is not surprising for an early-type galaxy.
Nearby galaxies
NGC 7020 is member of a sparse group of galaxies that contains IC 5084, IC 5092, IC 5096, NGC 6943, NGC 7083, NGC 7096, NGC 7125, NGC 7126 and ESO 107-14. However, NGC 7020 is not interacting with any other galaxy in the group.
See also
NGC 7098
NGC 7013
NGC 4429 galaxy in the Virgo Cluster with a similar structure
List of NGC objects (7001–7840)
References
External links
Ring galaxies
Lenticular galaxies
Barred lenticular galaxies
Pavo (constellation)
7020
66291
Astronomical objects discovered in 1836 | NGC 7020 | [
"Astronomy"
] | 312 | [
"Constellations",
"Pavo (constellation)"
] |
54,281,709 | https://en.wikipedia.org/wiki/Mazda%20Nagare%20%28car%20design%29 | Nagare is an automotive design language created by Franz von Holzhausen and Laurens van den Acker for Mazda. Incorporated into a number of concept cars, starting with the car of the same name, the Nagare design lineup was intended as a showcase of what Mazda's cars may have looked like in 2020.
It was abandoned by Mazda in 2011 in favour of the Kodo design series, starting with their Shinari concept car.
Motif and examples
The influence of the designs are wind and flow. These can be seen in the cars' design, where areas of the cars contain flowing lines.
Production cars in Mazda's late-2000s lineup, such as the second-generation Mazda3 and Mazda6, could easily be identified by swooping leaf-shaped headlamps, while the third-generation Mazda Premacy had flowing lines sculpted into the bodywork.
Nomenclature
All concept vehicles have names in which represent Nagare's "wind and flow" theme in one way or another.
Concept cars
Nagare
The Mazda Nagare is the first car built under the Nagare design language, and shares its name with the language itself. The car debuted at the 2006 LA Auto Show.
The Nagare takes the form of a long-wheelbase Kammback sports car. The futuristic interior is very irregular, with the driver placed front and center under the roof's highest point, and three additional passengers seated behind in a "wrap-around lounge". The Nagare also has butterfly doors that span nearly the entire wheelbase. The Nagare's engine is non-existent, as it is not a running prototype.
Designer Franz von Holzhausen mentioned during an interview at Autoblog that he took inspiration from nature and applied it to the Nagare concept. Some of von Holzhausen's words are typed below:"We began by studying motion and the effect it has on natural surroundings: how wind shapes sand in the desert, how water moves across the ocean floor, and the look of lava flowing down a mountainside. Natural motion registers an impression in your brain and that's what we hoped to capture with the new Nagare surface language. Once we started sketching our ideas, we weren't surprised to find similar quests underway in other product design disciplines. We found examples of motion influencing the shape and surface of furniture, architecture, apparel, and artwork. Nagare undoubtedly proves our confidence in identifying a new and exciting visual language for Mazda as we lead the way in defining the interaction of motion and flow in automobile surfacing."
Ryuga
The Mazda Ryuga is the second vehicle built under the Nagare series. The name references the purpose of the design. The car features gull-wing doors and a futuristic interior, hinting at Mazda's planned future in design. It is powered by a 2.5-litre Mazda MZR inline-four engine.
Hakaze
The Mazda Hakaze is the third car to be featured in the series. The car has a crossover body style with scissor doors. According to Mazda, the car was more production-ready than the Ryuga and Nagare. It is powered by a 2.3-litre MZR engine.
Taiki
The Mazda Taiki is the fourth vehicle featured in the series. The name is intended to complement the car's atmospheric canopy surrounding the driver and passenger; its interior continues the flowing design theme. The rear wheels appear to extend out from the body. Power comes from an improved version of the 13B Renesis Wankel engine used in the RX-8.
Furai
The Mazda Furai is the fifth car in the series. It is also the most storied and most popular Nagare-styled car.
The Furai is based on the Courage C65 LMP2 prototype that Mazda used for the American Le Mans Series. The car runs on E100 ethanol, making the Furai's R20B the first rotary engine to implement ethanol fuel. The engine is a midship-mounted R20B Renesis Wankel engine producing and coupled to a 6-speed Xtrac semi-automatic transmission. The engine was built by American company Racing Beat, who also made the rotor-shaped muffler. The name is also a reference to the Nagare "wind and flow" motif. The car wears the number 55 as a tribute to the Mazda 787B.
The Furai was tested on many circuits, such as Mazda Raceway Laguna Seca. In 2008, the car was destroyed after catching fire during a Top Gear photoshoot. This event was fully revealed to the public in 2013.
Kazamai
The Mazda Kazamai is the sixth Nagare car. Taking the form of a compact crossover designed for the Russian market, it is powered by a 2.0-litre engine with direct injection to increase both performance and fuel economy and decrease emissions. The name serves as its motif, with aerodynamic styling inspired by crosswinds, large 22-inch wheels, and the use of aluminium to reduce weight.
Kiyora
The Mazda Kiyora is the seventh car in the Nagare concept series. Unveiled at the 2008 Paris Motor Show, it is a water-themed, city-oriented compact car with transparent polycarbonate butterfly doors and a water filter that converts rainwater collected on the car's roof into drinking water. The Kiyora also possesses a haptic touchscreen designed to mimic the rippling of water.
References
Design language
Nagare car design | Mazda Nagare (car design) | [
"Engineering"
] | 1,114 | [
"Design",
"Design languages"
] |
54,281,870 | https://en.wikipedia.org/wiki/Diversity%20in%20open-source%20software | Researchers and journalists have found a higher gender disparity and lower racial and ethnic diversity in the open-source-software movement than in the field of computing overall, though a higher proportion of sexual minorities and transgender people than in the general United States population. Despite growing an increasingly diverse user base since its emergence in the 1990s, the field of open-source software development has remained homogeneous, with young men constituting the vast majority of developers.
Background
Open source software is a model of software development where source code is created by a number of volunteers and can be modified by other members of the community. The number of developers working on an open-source project can range from few to thousands, but in many projects only developers deemed trustworthy by the project maintainers will have the privilege of making additions to the main repository. The software developed as open-source is usually freely available to use, with the number of users varying from few to many millions.
Since its inception in the 1990s, as open-source software has continued to grow and offer new solutions to everyday problems, an increasingly diverse user base began to emerge. In contrast, the community of developers has remained homogeneous, dominated by young men.
Research on possible causes
In 2017, GitHub conducted a survey named the Open Source Survey, collecting responses from 5,500 GitHub users. Among the respondents, 18% personally experienced a negative interaction while working on open-source projects, but 50% of them have witnessed such interactions between other people. Dismissive responses, conflict, and unwelcoming language were respectively the third, fourth, and sixth most cited problems encountered in open-source.
Another study from 2017 examined 3 million pull requests from 334,578 GitHub users, identifying 312,909 of them as men and 21,510 as women from the mandatory gender field in the public Google+ profiles tied to the same email addresses as these users were using on GitHub. The authors of the study found code written by women to be accepted more often (78.6%) than code written by men (74.6%). However, among developers who were not insiders of the project, women's code acceptance rates were found to drop by 12.0% if gender was immediately identifiable by GitHub username or profile picture, with only a smaller 3.8% drop observed for men under the same conditions. Comparing their results to a meta-analysis of employment sex discrimination conducted in 2000, the authors observed that they have uncovered only a quarter of the effect found in typical studies of gender bias. The study concludes that gender bias, survivorship and self-selection bias, and women being held to higher performance standards are among plausible explanations of the results.
Diversity
Gender diversity
The more recent entering of women into the movement has been suggested as the cause of their under-representation in the field; of all women who had contributed to open-source software up until 2013, 38.45% of them began doing so from 2009 to 2013, in comparison to only 18.75% of men.
The gender ratio in open source is even greater than the field-wide gender disparity in computing. This was found by a number of surveys:
A 2002 survey of 2,784 open-source-software developers found that 1.1% of them were women.
A 2013 survey of 2,183 open-source contributors found that 81.4% were men and 10.4% were women. The survey included both software contributors and non-software contributors and found that women were much more likely to be non-software contributors.
In the GitHub's 2017 Open Source Survey 95% respondents identified as men and only 3% as women, while in the same year about 22.6% of professional computer programmers in the United States were female according to the United States Bureau of Labor Statistics.
Racial and ethnic diversity
In an 2013 article for the NPR, journalist Gene Demby considered Black people and Latinos to be underrepresented in the open source software development.
In the GitHub's 2017 Open Source Survey the representation of immigrants, from and to anywhere in the world, was 26%.
In the same survey, 16% of respondents identified as members of ethnic or national minorities in the country where they currently live, while according to the United States Bureau of Labor Statistics, Black, Asian, and Latino people accounted for a total of about 34% of programmers in the United States in 2017.
Sexual minority, non-binary, and transgender diversity
Among the respondents of GitHub's 2017 Open Source Survey 1% identified as transgender, 1% as non-binary, and 7% as lesbian, gay, bisexual, asexual, or another minority sexual orientation, while according to a Gallup poll in conducted in the same year 4.1% of the United States population identify as LGBT. A 2018 survey of software developers conducted by Stack Overflow found that out of their sample of 100,000, 6.7% in total identified as one of "Bisexual or Queer" (4.3%), "Gay or Lesbian" (2.4%), and "Asexual" (1.9%), while 0.9% identified as "non-binary, genderqueer, or gender non-conforming".
Organizations and programs
LinuxChix is a women-oriented Linux community founded in 1999 encouraging participation in Linux and open-source software by creating conflict-free and nurturing environments for women to do so. Open-source projects and organizations such as Arch Linux, Bitcoin, BonitaSoft, Debian , Drupal, Fedora , FreeNX, GNOME , KDE , Mozilla , PHP, Ubuntu have or had initiatives directed to women to support their participation.
See also
Gender disparity in computing
STEM pipeline
References
Diversity in computing
Open-source movement | Diversity in open-source software | [
"Technology"
] | 1,198 | [
"Computing and society",
"Diversity in computing"
] |
54,283,629 | https://en.wikipedia.org/wiki/Mineral%20jig | In metallurgy, mineral jigs are a type of gravity concentrator, separating materials with different densities. It is widely used in recovering valuable heavy minerals such as gold, platinum, tin, tungsten, as well as gemstones such as diamond and sapphire, from alluvial or placer deposits. Base metals such as iron, manganese, and barite can also be recovered using jigs.
The process begins with flowing a stream of liquid-suspended material over a screen and subjecting the screen to a vertical hydraulic pulsation. This pulsation momentarily expands or dilates the screen bed and allows the heavier materials to work toward the bottom. Heavier material finer than the screen openings will gradually work through the beds and the retention screen into the hutch, or lower compartment. That material, the concentrate, is discharged from this compartment or hutch through a spigot. If the concentrate is coarser than the screen, it will work down to the top of the shot bed, and can be withdrawn either continuously or intermittently. The lighter material, or tailing, will be rejected over the end of the jig.
The mineral jig has certain advantages in placer and hardrock mill flowsheets. In gold recovery, the jigs produce highly concentrated products which can be easily upgraded by methods such as barrel amalgamation, treating across shaking tables or processing through centrifugal concentrators. In other placer operations the heavy minerals being sought are recovered efficiently and cheaply with similar high ratios of concentration. In iron, manganese, and base metal treatment flowsheets, the jigs are operated to produce marketable grades of concentrate, or, as pre-concentration devices, to reject barren gangue prior to the ore entering the fine grinding section of the mill flowsheet.
The construction of the mineral jig results in maximum utilization of floor area and minimum head room requirements, permitting greater capacity per unit of operating floor area than, for example, shaking tables or other devices such as jig concentrators.
See also
Jig concentrators
Mineral processing
References
Mining equipment | Mineral jig | [
"Engineering"
] | 431 | [
"Mining equipment"
] |
54,283,761 | https://en.wikipedia.org/wiki/ABT-436 | ABT-436 is an orally active, highly selective vasopressin V1B receptor antagonist which was under development by Abbott Laboratories and AbbVie for the treatment of major depressive disorder, anxiety disorders, and alcoholism but was discontinued. It reached phase II clinical trials prior to the discontinuation of its development.
See also
Balovaptan
Nelivaptan
SRX-246
TS-121
References
Abandoned drugs
Experimental antidepressants
Anxiolytics
Drugs developed by AbbVie
Drugs with undisclosed chemical structures
Vasopressin receptor antagonists | ABT-436 | [
"Chemistry"
] | 119 | [
"Drug safety",
"Abandoned drugs"
] |
54,284,233 | https://en.wikipedia.org/wiki/Andr%C3%A1sfai%20graph | In graph theory, an Andrásfai graph is a triangle-free, circulant graph named after Béla Andrásfai.
Properties
The Andrásfai graph for any natural number is a circulant graph on vertices, in which vertex is connected by an edge to vertices , for every that is congruent to 1 mod 3. For instance, the Wagner graph is an Andrásfai graph, the graph .
The graph family is triangle-free, and has an independence number of . From this the formula results, where is the Ramsey number. The equality holds for and only.
The Andrásfai graphs were later generalized.
References
Bibliography
Related Items
Petersen graph
Cayley graph
Parametric families of graphs
Regular graphs | Andrásfai graph | [
"Mathematics"
] | 153 | [
"Graph theory stubs",
"Mathematical relations",
"Graph theory"
] |
54,284,329 | https://en.wikipedia.org/wiki/Methyl%20perchlorate | Methyl perchlorate is an organic chemical compound with the chemical formula . Its molecular structure is a methyl group covalently bonded by a single bond to a perchlorate group, , in which chlorine has an oxidation state of +7. Like many other perchlorates, it is a high energy material. It is also a toxic alkylating agent and exposure to the vapor can cause death. It can be prepared by treating iodomethane with a solution of silver perchlorate in benzene.
References
Perchlorates
Methyl esters | Methyl perchlorate | [
"Chemistry"
] | 113 | [
"Perchlorates",
"Salts"
] |
54,284,846 | https://en.wikipedia.org/wiki/Aquilanti%E2%80%93Mundim%20deformed%20Arrhenius%20model | In chemical kinetics, the Aquilanti–Mundim deformed Arrhenius model is a generalization of the standard Arrhenius law.
Overview
Arrhenius plots, which are used to represent the effects of temperature on the rates of chemical and biophysical processes and on various transport phenomena in materials science, may exhibit deviations from linearity. Account of curvature is provided here by a formula, which involves a deformation of the exponential function, of the kind recently encountered in treatments of non-extensivity in statistical mechanics.
Theoretical model
Svante Arrhenius (1889) equation is often used to characterize the effect of temperature on the rates of chemical reactions. The Arrhenius formula gave a simple and powerful law, which in a vast generality of cases describes the dependence on absolute temperature of the rate constant as following,
(1)
where is the absolute temperature, is the gas constant and the factor varies only slightly with temperature. The meaning attached to the energy of activation is as the minimum energy, which molecules need have to overcome the threshold to reaction. Therefore, the year 1889 can be considered as the birth date of reactive dynamics as the study of the motion of atoms and molecules in a reactive event. Eq. (1) was motivated by the 1884 discovery by van't Hoff of the exponential dependence from the temperature of the equilibrium constants for most reactions: Eq.(1), when used for both a reaction and its inverse, agrees with van't Hoff's equation interpreting chemical equilibrium as dynamical at the microscopic level. In case of a single rate-limited thermally activated process, an Arrhenius plot gives a straight line, from which the activation energy and the pre-exponential factor can both be determined.
However, advances in experimental and theoretical methods have revealed the existence of deviation from Arrhenius behavior (Fig.1).
To overcome this problem, Aquilanti and Mundim proposed (2010) a generalized Arrhenius law based on algebraic deformation of the usual exponential function. Starting from the Euler exponential definition given by,
(2)
defining the deformed exponential function as,
(3)
Identifying the deformation parameter as a continuous generalization of . At the limit the d-exponential function, , coincides with the usual exponential according to the well-known limit due to Euler, that is,
(4)
This definition was first used in thermodynamics and statistical mechanics by Landau. In the most recent scientific literature, there is a variety of deformed algebras with applications in different areas of science. Considering the d-exponential function, we introduce the deformed reaction rate coefficient, , in the following way,
(5)
and at the limit the usual Arrhenius reaction law is recovered (Figs.1 and 1a). is pre-exponential factor. Taking the logarithm of , Eq.(5), we obtain the following expression for the non-Arrhenius plot,
(6)
The logarithm of the reaction rate coefficient against reciprocal temperature shows a curvature, rather than the straight-line behavior described by the usual Arrhenius law (Figs.1 and 1a).
In Tolman’s definition the barrier or activation energy is a phenomenological quantity defined in terms of the slope of an Arrhenius law; it is usually assumed to be independent of absolute temperature (T), requires only local equilibrium and in general is given by
(7)
where is constant and is the ideal gas constant.
To generalize Tolman´s definition, in the case chemical reactions, we assume that the barrier or activation energy is a function of the temperature given by the following differential equation,
or → (8)
where (constant) at limit and the usual activation energy law is recovered as a constant. Noticeably, on the contrary of the usual Arrhenius case, the barrier or activation energy is temperature dependent and has different concavities depending on the value of the d parameter (see Figs.1 and 1a). Thus, a positive convexity means that decreases with increasing temperature. This general result is explained by a new Tolman-like interpretation of the activation energy through Eq.(8).
In the recent literature, it is possible to find different applications to verify the applicability of this new chemical reaction formalism
Apparent Reciprocal Activation Energy or Transitivity
can be considered as temperature dependent. It was postulated as the basic expansion the reciprocal-activation reciprocal-temperature relationship, for which can provide a formal mathematical justification by Tolman Theorem. The function when written as the logarithmic derivative of the rate constants with respect to , Eq. (7), the concept to an activation energy represents an energetic obstacle to the progress of the reaction: therefore its reciprocal can be interpreted as a measure of the propensity for the reaction to proceed and defined as the specific transitivity () of the process:
(9)
This notation emphasizes the fact that in general the transitivity can take a gamma of values, but not including abrupt changes e.g. in the mechanism or in the phases of reactants. If it is admit a Laurent expansion in a neighbourhood around a reference value, it is possible recover the Eqs. (6) and (8).
What it is call the sub-Arrhenius behaviour would be accounted for traditionally by introducing a tunnelling parameter () in the conventional Transition-State-Theory. In the -TST formulation, it is replace the factor in the TST rate constant by the deformed exponential function, Eq. (3), yielding:
(10)
where is Planck constant, is Boltzmann constant and is the (translational, vibrational and rotational) partition functions of the reactants, and is the partition function of the activated complex. In Ref., the significance of the parameter and an explicit procedure for its calculation were proposed, which it is inversely proportional to the square of the barrier height ()and directly proportional to the square of the frequency for crossing the barrier () at a saddle point in the potential energy surface:
(11)
Fields of Applications and Related Subjects
This theory was initially developed for applications in chemical kinetics problems as above discussed, but has since been applied to a wide range of phenomena:
the characterization of reaction rates in Chemistry,
Transition state theory (TST),
Astrochemical process,
quantum tunneling,
stereodynamics stereochemistry of kinetics processes, solid-state diffusive reactions,
physical processes in supercooled liquids,
carbon nanotubes composite,
transport phenomena,
anomalous diffusion,
Brownian particles moving,
transport dynamics in ionic conductors,
a continuum approach for modeling gravitational effects on grain settling and shape distortion,
collision theory,
rate theory connecting kinetics to thermodynamics,
nonextensive statistical mechanics,
different fields of plasma chemical-physics,
modelling of high-temperature dark current in multi-quantum well structures from MWIR to VLWI,
molecular semiconductor problems,
Metallurgy: perspectives on lubricant additive corrosion,
Langevin stochastic dynamics,
predicting solubility of solids in supercritical solvents,
survey on operational perishables (food) quality control and logistics,
activation energy’s on biodiesel reaction,
flux over population analysis,
molecular quantum mechanics,
biological activity,
drug design,
protein folding.
Motor proteins,
Microbial growth laws,
Water dynamics
Classroom on Motivation and Sociability
Virial coefficients in chemical reaction
Diffusion in a binary colloidal mixture
Claisen–Schmidt condensation
Thermotherapy
Landscape topography
3D-printed powder components
Glass alloy
Li-ion Batteries
References
Chemical kinetics | Aquilanti–Mundim deformed Arrhenius model | [
"Chemistry"
] | 1,590 | [
"Chemical reaction engineering",
"Chemical kinetics"
] |
54,285,001 | https://en.wikipedia.org/wiki/Cyclocycloid | A cyclocycloid is a roulette traced by a point attached to a circle of radius r rolling around, a fixed circle of radius R, where the point is at a distance d from the center of the exterior circle.
The parametric equations for a cyclocycloid are
where is a parameter (not the polar angle). And r can be positive (represented by a ball rolling outside of a circle) or negative (represented by a ball rolling inside of a circle) depending on whether it is of an epicycloid or hypocycloid variety.
The classic Spirograph toy traces out these curves.
See also
Centered trochoid
Cycloid
Epicycloid
Hypocycloid
Spirograph
External links
Plane curves | Cyclocycloid | [
"Mathematics"
] | 161 | [
"Planes (geometry)",
"Euclidean plane geometry",
"Plane curves"
] |
54,285,105 | https://en.wikipedia.org/wiki/Animal%20Cognition | Animal Cognition is a peer-reviewed scientific journal published by Springer Science+Business Media. It covers research in ethology, behavioral ecology, animal behavior, cognitive sciences, and all aspects of human and animal cognition. According to the Journal Citation Reports, the journal has a 2020 impact factor of 3.084.
References
External links
Ethology journals
English-language journals
Academic journals established in 1998
Springer Science+Business Media academic journals
Cognitive science journals
Animal cognition | Animal Cognition | [
"Biology"
] | 93 | [
"Behavior",
"Animals",
"Ethology journals",
"Animal cognition",
"Ethology"
] |
54,285,127 | https://en.wikipedia.org/wiki/Landau%20Gold%20Medal | The Landau Gold Medal () is the highest award in theoretical physics awarded by the Russian Academy of Sciences and its predecessor the Soviet Academy of Sciences. It was established in 1971 and is named after Soviet physicist and Nobel Laureate Lev Landau. When awarded by the Soviet Academy of Sciences the award was the "Landau Prize"; the name was changed to the "Landau Gold Medal" in 1992.
Prize laureates
1971 - Vladimir Gribov
1974 - Evgeny Lifshitz, Vladimir Belinski, and Isaak Khalatnikov
1977 - Arkady Migdal
1980 - Aleksandr Gurevich and Lev Pitaevskii
1981- Eva Jablonka
1983 - Alexander Patashinski and Valery Pokrovsky
1986 - Boris Shklovskii and Alexei L. Efros
1989 - Alexei Abrikosov, Lev Gor'kov, and Igor Dzyaloshinskii
1992 - Grigoriy Volovik and Vladimir P. Mineev
1998 - Spartak Belyaev
2002 - Lev Okun
2008 - Lev Pitaevskii
2013 - Semyon Gershtein
2018 - Valery Pokrovsky
See also
List of physics awards
Prizes named after people
References
Awards established in 1971
Civil awards and decorations of Russia
Civil awards and decorations of the Soviet Union
Physics awards
Awards of the Russian Academy of Sciences
USSR Academy of Sciences
1971 establishments in the Soviet Union | Landau Gold Medal | [
"Technology"
] | 283 | [
"Science and technology awards",
"Physics awards"
] |
61,850,278 | https://en.wikipedia.org/wiki/The%20Quarterly%20Journal%20of%20Mechanics%20and%20Applied%20Mathematics | The Quarterly Journal of Mechanics and Applied Mathematics is a quarterly, peer-reviewed scientific journal covering research on classical mechanics and applied mathematics. The editors-in-chief are P. W. Duck, P. A. Martin and N. V. Movchan. The journal was established in 1948 to meet a need for a separate English journal that publishes articles focusing on classical mechanics only, in particular, including fluid mechanics and solid mechanics, that were usually published in journals like Proceedings of the Royal Society and Philosophical Transactions of the Royal Society.
Abstracting and indexing
The journal is abstracted and indexed in,
References
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Oxford University Press academic journals
Mathematical physics journals
Physics journals
English-language journals
Academic journals established in 1948
Quarterly journals
Applied mathematics journals | The Quarterly Journal of Mechanics and Applied Mathematics | [
"Mathematics"
] | 150 | [
"Applied mathematics",
"Applied mathematics journals"
] |
61,851,709 | https://en.wikipedia.org/wiki/Machiavellianism%20%28psychology%29 | In the field of personality psychology, Machiavellianism (sometimes abbreviated as MACH) is the name of a personality trait construct characterized by interpersonal manipulation, indifference to morality, lack of empathy, and a calculated focus on self-interest. Psychologists Richard Christie and Florence L. Geis created the construct and named it after Niccolò Machiavelli, as they used truncated and edited statements similar to his writing style to study variations in human behaviors. The construct's relation to the thinker himself is exclusively nominal. Their Mach IV test, a 20-question, Likert-scale personality survey, became the standard self-assessment tool and scale of the Machiavellianism construct. Those who score high on the scale (High Machs) are more likely to have a high level of manipulativeness, deceitfulness and a cynical, unemotional temperament.
It is one of the dark triad traits, along with the subclinical versions of narcissism and psychopathy.
Origin of the construct
Adapting Machiavelli for psychometric use
In 1955, psychologist Richard Christie set out to study the thought processes and actions of those who manipulated others, such as political ideologues and religious extremists. He found that there was much literature on those who followed organizations and movements, but very little on those who led them. He began by conceptualizing what qualities a potential manipulator would have, such as a lack of empathy and affect, and being unconcerned with moral standards. Then as Christie was developing a psychometric for interpersonal manipulation, he was reminded of his encounter with Machiavelli's writings as an undergraduate, and wanted to adapt them to suit his research. In the 1960s, Christie and his colleagues would then develop a test using a selection of statements, including truncated and edited sentences that they viewed were similar to the general writing style found in Machiavelli's works such as The Prince and The Discourses on Livy as test items, naming the construct "Machiavellianism" after him. They wanted to assess whether or not those who were in agreement with the statements would behave differently than others who disagreed, specifically in regards to manipulative actions. Christie and his research partner Florence L. Geis published their results in their book, titled "Studies in Machiavellianism", in 1970.
Christie made light of the difficulty in adapting Machiavelli's writings into a non-political test, joking that his advice was "better suited for Renaissance princes" than for college undergraduates. Christie used more colloquial, everyday wording when creating the scale items. Thus the test items used were "theoretically congruent with" or loosely based on Machiavelli's tone, instead of literal, direct statements from his works.
On the name of the scale
While the construct is named "Machiavellianism", it does not refer to the political theory espoused in Machiavelli's books (also called Machiavellianism). Because the two concepts share the same name, they can be confused for and conflated with one another, even though his political ideas are not relevant to psychology. Scholars have asserted that the variable has no relation to Machiavelli outside of bearing his name, and that it has nothing to do with Machiavelli's politics. Christie himself makes clear that he used sentences inspired by Machiavelli's works only as a sort of litmus test to study deceptive and manipulative behavior, and that his concern was not with Machiavelli's historical or political influence, stating specifically that:
Historians disagree as to whether Machiavelli was a cynic who wrote political satire, a patriot, or the first modern political scientist. The present concern is not with Machiavelli as an historic figure, but as the source of ideas about those who manipulate others.
Christie stated that he chose the name "Machiavellianism" out of convenience seeing as other names such as "M scale" (M for manipulation) and "Ma scale" (which was used by the Minnesota Multiphasic Personality Inventory for hypomania) were taken. Names also considered were the "manipulator" or "operator" scale, but these terms had issues regarding behavioral validity. He also admits that by using the name "Machiavellianism", the scale would "create problems of public misunderstanding" due to the pre-existing political meaning of the term. In a later essay, Christie even states that some have viewed the name problematic and that "the use of the word Machiavellianism to describe the content of the scales has been questioned".
MACH-IV
Christie and Geis's MACH IV test, a 20-question, Likert-scale personality survey, became the standard self-report tool to measure one's level of Machiavellianism. Those who score highly on the scale are classified as high Machs, while those who score low are classified as low Machs. "Machiavellian" is also used but has a far more technical use in this context, primarily in reference to this scale and those who score high on it. Using their scale, Christie and Geis conducted multiple experimental tests that showed that the interpersonal strategies and behavior of "high Machs" and "low Machs" differ. People scoring high on the scale tend to endorse manipulative statements, and behave accordingly, contrary to those who score lowly. People scoring high on the scale tend to endorse statements such as, "Never tell anyone the real reason you did something unless it is useful to do so," (No. 1) but not ones like, "Most people are basically good and kind" (No. 4), "There is no excuse for lying to someone else" (No. 7) or "Most people who get ahead in the world lead clean, moral lives" (No. 11) Their basic results have been widely replicated. Measured on the Mach IV scale, males score, on average, slightly higher on Machiavellianism than females.
The Mach IV test influenced the creation of an assessment called the Dirty Dozen, which contains 12 items, and the Short Dark Triad, composed of 27 items. The MACH-IV (and other Machiavellianism tests) also feature questions loosely inspired by other thinkers such as Chinese political authors, not just Machiavelli.
High vs Low Machiavellianism
Like all personality traits, Machiavellianism is a characteristic that exists on a spectrum or continuum. Christie and others noted that High Machs were more likely to cheat in experimental games, manipulate others around them, and were generally detached in their interactions. This was opposed to the behavior of Low Machs, who found such behaviors immoral, and refrained from them.
The higher a person is on the Machiavellianism scale, the more likely they are to deceive and exploit at the expense of someone else, engage in unprincipled behavior, and have a lack of empathetic feelings.
Core features
In developing the construct, Christie theorized that a "manipulator" or "operator" would possess the following characteristics:
1. A relative lack of affect in interpersonal relationships: Manipulators do not empathize with their victims. The more empathy one has, Christie says, the less likely one will manipulate a person to do their bidding.
2. A lack of concern for conventional morality: Christie asserts that the manipulator is not concerned with the morality of behaviors such as lying and cheating.
3. A lack of gross psychopathology: Christie states that manipulators usually have an instrumentalist view of the world, which shows a lack of psychosis or other mental impairments.
4. Low ideological commitment: Manipulators prefer to focus on getting things done pragmatically rather than focus on ideological allegiances. Christie states that while manipulators are to be found in organizations of differing ideals, they are more likely to be interested in tactics that achieve individual ends than inflexible idealistic ones.
Five-Factor Model
Under the recently devised Five-Factor Model of Machiavellianism, three characteristics underlie the construct:
Antagonism: manipulativeness, cynicism, selfishness, callousness, and arrogance.
Planfulness: deliberation and orderliness.
Agency: achievement-striving, assertiveness, self-confidence, emotional invulnerability, activity and competence.
Causes
Genetics and upbringing
Several behavioral genetics studies have shown that Machiavellianism has both significantly genetic and environmental influences. Researchers have noted that while Machiavellianism is heritable to a substantial degree, it can also be influenced by the shared-environment (i.e. sibling groups) slightly more than narcissism and psychopathy. Other traits associated with Machiavellianism are influenced by genetics as well, as one study notes that "The co-occurrence of alexithymia and Machiavellianism was most heavily influenced by genetic factors, and to a lesser but significant extent by non-shared environmental factors." Machiavellianism is also heavily correlated with primary psychopathy which is itself strongly heritable. A study on the "core" of dark triad traits also emphasized that the residual traits of Machiavellianism had "significant genetic components". The relationship between Machiavellianism and mental toughness is also moderated by environmental factors and a genetic basis.
One particular study found a gene responsible for dopamine reception was positively associated with individuals who scored high on the MACH IV, but it is unclear what specific mechanisms cause this effect. A study noted that the emotionality of Machiavellianism may also be genetically determined, with the authors stating that "it can be expected that in the case of Machiavellianism, the genetic influence may manifest itself by affecting the emotional sphere. That affective insensitivity – as McIlwain (2003) designates it--makes Machiavellians similar to psychopaths. In the study by Vernon et al (2008), genetic factors for Machiavellianism and psychopathy were correlated, which suggests that the variability of both qualities is greatly affected by the same genes. The genetically determined “cool syndrome” makes it easier for the child to use effective manipulation, leading to the development of a permanent behaviour strategy, at the same time protecting the child from internal punishments such as shame or guilt."
Studies have found a link between Machiavellianism and a blunted cortisol awaking response (CAR). A person's cortisol awaking response has been associated with a lack of affective empathy, and is highly heritable.
Environmental causes
The environmental causes (such as shared, and non-shared environment) that contribute to the development of machiavellianism were childhood maltreatment and neglect, social reinforcement of manipulative behaviors from an early age, and poor family functioning. One study even stated that "the etiology of Machiavellianism, similarly to the development of a dismissing-avoidant pattern, partly originates from childhood experiences obtained in relationships with unexpressive, less understanding, highly punitive or restrictive caregivers". In many studies, Machiavellianism has been heavily correlated with negative home atmospheres, loneliness, and adverse parental experiences. One study noted that punishment specifically led to the "emergence of deceitful and exploitative interpersonal tactics." The authors of the study concluded that these results "might give further support for the idea that Machiavellian personality traits are possible strategic responses to childhood adversities". Another study found the traits of Machiavellianism to be a response to early maladaptive schemas (EMS), essentially coping mechanisms for emotional deprivation, mistrust, abuse, and caregiver rejection. Irregular parent care, such as a mother being neglectful and a father being overprotective, has also been correlated with Machiavellianism. The hereditary influence on Machiavellianism may make it challenging to disentangle the genetic underpinnings from the effects of parental upbringing and environmental factors. Another study also echoed similarly that it is difficult to separate genetic contributions from parenting environments, and that "negative fathers might be high on Machiavellian traits and therefore, the transmission might be genetic rather than experiential".
In general, Jones (2020) asserts that "there may be a myriad of reasons, including some environmental reasons, as to why someone would become cynical, habitually ignore morality, or use manipulative persuasion. There may be others who are born cynical, manipulative, and amoral. Thus, there may be differences in etiology that lead to differences in how fixed the trait is, and how it is expressed".
Machiavellianism in children
Ever since the creation of the construct in the 1960s, there has been extensive research on Machiavellianism in young children and adolescents, via a measure dubbed the "Kiddie Mach" test. The first study was done in 1966 as a part of Dorothea Braginsky's doctoral dissertation, with the subjects being as young as 10 years old. Studies have shown that traits of Machiavellianism and other dark triad traits were already present in preschool children, and more pronounced in adolescents aged 11–17. There have been studies to measure Machiavellianism in 6 year olds using adult informants to analyze the child's behavior. Deceptive behaviors by children even as young as 3 were also investigated heavily. Peer reports suggest that children higher in Machiavellianism exhibit behaviors such as using both prosocial and coercive strategies based on how much is to be gained in a situation, and they tend to manipulate indirectly. Children who score highly on the Machiavellianism scale tend to be more successful in manipulation, do it more frequently, and are judged as better at manipulation than those who score lower. Parental levels of Machiavellianism seem to have a slight effect on the child's own level. Machiavellianism levels in fathers was positively correlated with the Machiavellianism levels of their children, but the mother's level had no significant effect. One study concluded that "parental Machiavellianism is a predictor and perhaps a cause of children's Machiavellian beliefs and their manipulative success". Machiavellianism is also correlated with childhood aggression, especially concerning the control of social hierarchies. One study found a trend upwards with respect to Machiavellianism from late childhood to adolescence, when levels of Machiavellianism are thought to peak. From adolescence throughout adulthood there is a significant and steady downward trend with regard to levels of Machiavellianism, until the age of 65 where an overall lifetime minimum is reached.
Peer ratings of children high on Machiavellianism are inconsistent, with some researchers reporting that juvenile High Machs are rated as popular, and some reporting that they are less well liked by peers. A study involving Greek children ages 8–12 noted that the children highest in Machiavellianism showed aggressive tendencies and were more likely to bully others, though the tactics varied by gender.
Dark triad
In 1998, John McHoskey, William Worzel, and Christopher Szyarto proposed that narcissism, Machiavellianism, and psychopathy are more or less interchangeable in normal samples. Delroy L. Paulhus and McHoskey debated these perspectives at an American Psychological Association conference, inspiring a body of research that continues to grow in the published literature. Delroy Paulhus and Kevin Williams found enough differences between the traits to suggest that they were distinct despite their similarities, thus the concept of a "triad" of offensive personality traits was conceptualized. There has been research on Machiavellianism using various dark triad measures, including the Short Dark Triad (SD3), and the Dark Triad Dirty Dozen test.
Miller, Lynam, and Sharpe (2022) state that the reason why the multidimensional nature of Machiavellianism has "received less attention" is because there is "little research on Machiavellianism outside the context of the D3".
Psychopathy
Many psychologists consider Machiavellianism to be essentially indistinguishable from psychopathy, as they both share manipulative tendencies, disregard for morality, and cold callousness as their primary attributes. There is an immense and ongoing debate amongst researchers as to whether or not Machiavellianism and psychopathy should be treated as the same construct, or at least treat Machiavellianism as a subset of psychopathy. When tested, High Machs scored consistently high on measures of psychopathy, more than Low Machs. Primary psychopaths also scored higher on the Machiavellianism scale than secondary psychopaths. According to John McHoskey, the MACH-IV test is merely "a global measure of psychopathy in noninstitutionalized populations", and that this is a result of the disconnect between clinical and personality psychology. Many have stated that the Machiavellianism scale measures nothing more than "successful" psychopathy, or psychopathy without the extreme clinical characteristics. Even compared to other "dark" traits, research has shown that Psychopathy correlates with Machiavellianism far more than it correlates with narcissism. Some authors have stated that Machiavellianism and psychopathy represent the issue of a jangle fallacy, as both constructs are named differently yet describe the same concept. A recent paper published in 2022 stated that Machiavellianism "is theoretically distinct from psychopathy, but empirically they are nearly indistinguishable". Beverly Fehr even suggested that psychopaths may be simply "High Machs who have had run up against the law". Robert Hare, author of the Psychopathy Checklist, stated that Machiavellianism is more closely related to PCL Factor 1, affective detachment, than to Factor 2, an antisocial lifestyle. According to Christopher Patrick, high Psychopathy Checklist scores correlated with much higher Machiavellianism scores, as well as higher scores on boldness and aggressiveness.
Researchers note that Machiavellianism is well represented in every measure of psychopathy, such as the Factor 1 characteristics on the Psychopathy Checklist, more specifically traits such as "conning/manipulative", "pathological lying,” "callous/lack of empathy", and “glibness/superficial charm”. Donald Lynam and others noted that Machiavellianism is also represented in the "Interpersonal Manipulation" factor in Hare's Self-Report Psychopathy Scale-III and in the "Manipulation" scale in the Elemental Psychopathy Assessment. The researchers state that "ultimately, measures of psychopathy and MACH appear to be measuring the same construct, and MACH assessments fail to capture the construct as articulated in theoretical descriptions". Michael Levenson, author of the Levenson Self-Report Psychopathy Scale, disagreed with the notion of distinguishing machiavellianism from psychopathy, stating that it "does not accord" with empirical research which shows Machiavellianism being heavily related to primary psychopathy. Machiavellianism has a strong relationship with both primary and secondary psychopathy on Levenson's self report test. In experiments High Machs also scored highly on the Psychopathic Deviate subscale on the MMPI. On the Psychopathic Personality Inventory, created by Scott Lilienfeld and Brian Andrews, there is even a subscale similarly named "Machiavellian Egocentricity". The subscale is said to assess a "ruthless and self centered willingness to exploit others". Machiavellianism and psychopathy have both been negatively correlated with the recognition of facial emotions, with one study stating that "if the ability to recognise facial expressions is exclusively an affective empathy task, it indeed accounts for the facial recognition deficits found in primary psychopathy and Machiavellianism." High scores on the Triarchic Psychopathy Measure questionnaire strongly correlated with Machiavellianism. One group of researchers noted that by definition, "the interpersonal features of psychopathy involve a calculating, cunning, and manipulative style" thus a highly psychopathic person is ipso facto also a person high on Machiavellianism.
Machiavellianism and psychopathy overlap so heavily that researchers have proposed merging the two traits into each other, preferably incorporating Machiavellianism into psychopathy. There have been attempts to combine Machiavellianism and psychopathy into one construct, such as the creation of a "Dark Dyad" as opposed to a "Dark Triad", with the exclusion of narcissism.
A recent study done on criminal psychopaths noted that Machiavellianism showed the strongest association with the affective aspect of psychopathy.
Difference between constructs:Impulse control
Many other psychologists state that while Machiavellianism and psychopathy overlap heavily, there is much evidence to suggest that they are distinct personality constructs. Psychologists who stress the differences between Machiavellianism and psychopathy state that, in total contrast to high Machs, psychopaths are impulsive, tend to be reckless, and lack long term planning skills. Delroy Paulhus and others have stated that this difference between the two traits is often underappreciated. Scholars also note that those high on Machiavellianism can delay gratification, and have more sensitivity to punishment and awareness of consequences than psychopaths. Though both traits have a heritable basis, Machiavellianism is more influenced by the environment than psychopathy. High Machs have been described as "master manipulators" and far better at manipulation than psychopaths and narcissists.
Daniel Jones notes that even though both psychopaths and High Machs share a manipulative and callous nature, the difference between Machiavellianism and psychopathy lies in the type of manipulation employed by the two constructs. Machiavellianism is marked by calculated planning, and manipulating only when something is to be gained, while psychopathy is marked by rashness, and manipulating regardless of situation. O'Boyle and others found however that the notion that Machiavellianism is marked by cautiousness does not match empirical research which shows that it can be correlated with reckless behavior in certain situations.
In response to this interpretation, Miller et al (2017) responded by saying that empirical research casts "substantial doubt" on the notion of Machiavellianism being distinguishable from psychopathy, and that ultimately literature on Machiavellianism should be framed as an alternative literature on psychopathy, as they view that Machiavellianism literature is far more helpful in understanding psychopathy.
Narcissism
Individuals high in Machiavellianism and narcissism both manipulate to improve their reputations, and how they appear to others. Individuals high in the two traits do this as a form of self aggrandizement to help their chances of success in a given situation. Machiavellianism scores were positively associated with aspects of narcissism such as entitlement and exploitativeness, and inversely associated with adaptive narcissistic tendencies, like self-sufficiency. Studies have also shown that those higher on Machiavellianism are more realistic about their character, while narcissists are less realistic about theirs. Compared to High Machs, narcissists are less malevolent and show a more socially positive personality. They also have higher levels of self-rated happiness.
Machiavellianism and narcissism both share a lack of empathy and a focus on self-interest, though the two traits differ in how they manifest in people, and what their motivations are. High Machs have tendencies to be driven by personal gain, whereas narcissists are driven by a need for validation and admiration. Opposed to those high on narcissism, High Machs tend to be more strategic and calculating in their interpersonal interactions, while narcissists may be more impulsive and attention-seeking.
In terms of social relationships, High Machs are more likely to be more exploitative towards others, while narcissists may be more likely to seek out relationships that serve to bolster their self-esteem and provide them with the admiration they desire.
Compared to subclinical narcissists, High Machs exhibit a greater lack of empathy, because of the emotional deficiencies inherent within Machiavellianism.
White collar crime
Research has shown that individuals high in Machiavellianism may be more willing to engage in white collar crimes. Psychologist Daniel Jones has stated that "individuals higher on Machiavellianism are well suited for crimes in the financial world, especially crimes that skirt the legal system". Delroy Paulhus has stated that Machiavellianism is the main trait for white collar criminals and con artists, and not psychopathy, stating that:
Although direct research on this topic is difficult, it seems clear that malevolent stockbrokers such as Bernie Madoff do not qualify as psychopaths: They are corporate Machiavellians who use deliberate, strategic procedures for exploiting others. A genuine psychopath, even at the subclinical level, lacks the self-control to orchestrate the schemes of a shrewd stockbroker.
In a research paper, Daniel Jones and others stated that a person high on Machiavellianism would also be possibly drawn to cybercrime, noting that "although we did not directly assess crimes, we did find patterns of system infiltration that were different among the three traits, with Machiavellianism being associated with the stealthiest approach among the three traits." They also stated that Machiavellianism would only be associated with crime if the "benefits outweighed the risks". They went on to clarify that this is opposed to individuals high in psychopathy, whom are prone to crime regardless of the situation.
Other "dark" groupings
Machiavellianism has been featured in many other groupings of dark traits, such as the dark tetrad, which adds sadism to the dark triad traits. The characteristics of Machiavellianism have also been viewed as potentially correlated with sadism.
The paper titled "The Dark Core of Personality" introduced a theoretical framework to understand various "dark traits" in personality as manifestations of a single underlying factor called the Dark Factor of Personality. This factor represents a general dispositional tendency where individuals prioritize their own utility (self-interest) at the expense of others, often justifying their actions through certain beliefs. The concept of D encapsulates all of the main "dark traits", with the addition of Spitefulness, Egoism, Moral Disengagement, Entitlement, and Self-interest. The authors of the study argued that while Machiavellianism, along with other dark traits like Narcissism and Psychopathy, has its unique features, it also shares a common core with these traits, which is encapsulated in the D factor. This means that people who score high in Machiavellianism tend to exhibit behaviors that prioritize their own benefit over others' which correlate with characteristis that align with the D factor. It is said that manipulativeness and callousness is responsible for the covariances among the dark personalities in general.
The light triad is a personality model that contrasts the dark triad, which comprises Kantianism, faith in humanity, and humanism. Kantianism was compared to Machiavellianism as its opposite, as it is characterized by a non-exploitative orientation. Both Kantianism and Machiavellianism are traits which are tongue-in-cheek references to philosophers. The "Light Triad" and its characteristics were most strongly negatively correlated with Machiavellianism.
DSM: Trait, not disorder
Machiavellianism has never been considered a disorder, nor has it been referenced in any version of the Diagnostic and Statistical Manual of Mental Disorders or International Classification of Diseases. It has been treated as strictly a personality construct. It is primarily studied by personality psychologists, as it is a non-clinical personality style.
Relations with other personality traits
There is immense literature concerning the relationships between Machiavellianism and other personality dimensions, such as the traits in the Big Five trait model. Machiavellianism has also been related to interpersonal aggression and hostile behavior.
Big Five
Mach-IV scores are negatively correlated with agreeableness (r = −0.47) and conscientiousness (r = −0.34), two dimensions of the Big Five personality model (NEO-PI-R). The FFMI corrects for this by including aspects of high conscientiousness in the scale (e.g. order, deliberation). Additionally, Machiavellianism correlates more highly with the honesty-humility dimension of the six-factor HEXACO model than with any of the big five dimensions. Machiavellianism has also been located within the interpersonal circumplex, which consists of the two independent dimensions of agency and communion. Agency refers to the motivation to succeed and to individuate the self, whereas communion refers to the motivation to merge with others and to support group interests. Machiavellianism lies in the quadrant of the circumplex defined by high agency and low communion. Machiavellianism has been found to lie diagonally opposite from a circumplex construct called self-construal, a tendency to prefer communion over agency. This suggests that people high in Machiavellianism do not simply wish to achieve, they wish to do so at the expense of (or at least without regard to) others.
Hot and cold empathy
There are two distinct types of empathy which people use to relate to each other which are referred to as hot and cold empathy.
Cold empathy (or cognitive empathy) refers to the understanding of how others might react to one's actions or a certain event.
Hot empathy (or emotional/affective empathy) refers to the emotional reaction others might have to the emotions of another person.
Machiavellianism was consistently negatively correlated with affective empathy in practically every study. Machiavellianism was also negatively correlated with affective resonance (feeling good when others feel good) and positively associated with affective dissonance (e.g. feeling happy when others are sad). People high in Machiavellianism tend to have a better understanding of cold empathy and do not feel hot empathy which explains why they seem cold and uncaring. Research results have also suggested that High Machs are deficient only at the level of affective empathy (sharing of emotions), whereas their cognitive empathy is intact, even high. Another study suggested that high Machs are deficient at both kinds of empathy. Studies also assert that high Machs do not feel guilt or remorse over the consequences of their manipulations. High Machs are less likely to be altruistic, and they are less likely to be concerned with the problems of others. High Machs are also less emotionally expressive and have a hard time recognizing and understanding the emotional states of others. One study proposed that High Machs have more automatic (that is, unconscious) recognition of other's negative emotions more than low Machs, and though they don't internalize these feelings, the understanding of those emotions may in fact aid in the manipulation of others. Children who scored higher on Machiavellianism showed a lack of empathy and more delinquent behaviors compared to those who scored lower, such as a lack of guilt, lying, cheating, and truancy.
Some authors have stated that since Machiavellianism is so diametrically opposed to empathy, it should be included in empathy scales as the polar opposite. Total scores on Machiavellianism and empathy were "significantly negatively correlated".
Unemotionality
One of the primary traits of machiavellianism is a detached, unemotional attitude and lack of affect in regards to others. Christie and Geis noted that the primary difference between high machs and low machs was the degree of emotion invested in interpersonal relations, with those scoring high having the lowest.
Research has been done on the extent of the low emotionality of those who score high on the Machiavellianism scale. Doris Mcllwain noted that "Machiavellians do not inhabit the realm of emotion in the same way as others, yet they use it to manipulate others. They do not experience feelings, empathy, or morality in normative ways. yet they are consummate manipulators and deceivers precisely by playing upon these sentiments and convictions in others. Thus they induce in others the guilt they hardly feel themselves." A study done by Farah Ali and others noted that Machiavellianism seems to have emotional reactions to stimuli similar to primary psychopathy, differing only in higher levels of anxiety, which those who score highly on machiavellianism may be prone to. Machiavellianism has an unclear relation with anxiety levels, some researchers have found positive correlations, while some have found no relation at all. High Machs demonstrate reduced skills in expressing their emotions.
A recent analysis discovered that, in addition to acting for mostly self interest and profit, High Machs used significantly less words when referring to emotional involvement. They concluded that "this study confirmed previous findings that High Machs have a cool and rational character and a pro-self orientation and showed that their lack of group orientation may account for their low cooperation in social dilemmas."
Alexithymia is also considered a key trait that has correlations with Machiavellianism. It is the lack of awareness of one's own emotions as well as the emotions of others. When tested, healthy alexithymic individuals have been found to obtain high Machiavellianism scores. This was not surprising to researchers, seeing as the unemotionality of Machiavellianism shows similarities to what alexithymics experience. One study examined the relationship between alexithymia and endorsement of beliefs associated with Machiavellianism amongst university students. Results showed a positive correlation between alexithymia and exploitative beliefs, suggesting those with higher levels of alexithymia were more likely to endorse the view that manipulating others is an effective strategy.
Neuroticism and depression
Researchers have often debated the potential links between Machiavellianism and a neurotic, anxious disposition. In a study done by psychologists Hans Eysenck, his wife Sybil, and John Allsopp, they note that they found "virtually no relationship" between Machiavellianism and neuroticism, unlike the relationships they found with Machiavellianism and Extraversion-Psychoticism respectively. However John McHoskey found links between Machiavellianism and neuroticism, along with the other personality traits popularized by Eysenck. Studies using measures of the Big Five personality traits have variously found positive or no correlation between Machiavellianism and Neuroticism.
Machiavellianism has very scant correlations with depression, and the higher one's Machiavellianism score was, the lower their depression level was. One study even noted that depressed males "were significantly less Machiavellian than were nondepressed males". They then estimate that "depression in males, then, may be of a more self-aggressive, self-destructive nature". High Machs who have higher levels of emotional intelligence scores show less depressive symptoms.
Motivation
A 1992 review described the motivation of those high on the Machiavellianism scale as related to cold selfishness and pure instrumentality, and those high on the trait were assumed to pursue their motives (e.g. sex, achievement, sociality) in duplicitous ways. More recent research on the motivations of high Machs compared to low Machs found that they gave high priority to money, success, and competition and relatively low priority to community building, self-love, and family commitment. High Machs admitted to focusing on unmitigated achievement and winning at any cost. The research on behaviors which high Machs engage in suggest that they are willing to achieve their goals by bending and breaking rules, cheating, and stealing. People high in Machiavellianism are able to easily switch between working with others to taking advantage of others to achieve their goals, and they are more willing to do things others see as terrible or immoral.
Intelligence and other cognitive skills
Due to their skill at interpersonal manipulation, there has often been an assumption that high Machs possess superior intelligence, or ability to understand other people in social situations. Recent research provides some support for this assumption. However, other research has established that Machiavellianism is unrelated to IQ. Paulhus and Williams found "significant associations of psychopathy and Machiavellianism with a relatively higher nonverbal to verbal IQ score".
Studies on emotional intelligence have usually found that high Machiavellianism is associated with low emotional intelligence as assessed by both performance and questionnaire measures.
Research has examined the relationship between trait emotional intelligence (EI), Machiavellianism, and the personality trait of agreeableness. The findings of one paper revealed that while trait EI and the ability to manage others' emotions were negatively correlated with Machiavellianism, this relationship was mediated by agreeableness. Specifically, those high in trait EI tended to be low in Machiavellianism primarily because they were high in agreeableness, reflecting a cooperative and prosocial nature. One study found that Machiavellianism was negatively associated with most facets of socio-emotional intelligence (SEI), including social expressivity, social sensitivity, emotional expressivity, and emotional sensitivity. However, Machiavellianism showed no significant relationship with emotional control, which involves regulating one's own emotional displays. Machiavellianism was positively associated with emotional manipulation, the tendency to strategically influence others' emotions. Despite this association, Machiavellianism did not moderate the relationship between any facet of SEI and emotional manipulation. This suggests that while High Machs have a propensity for emotionally manipulative behavior, they may not be utilizing socio-emotional skills towards that end. The authors propose this could be due to the High Mach's externally-oriented and unemotional perspective.
Both emotional empathy and emotion recognition have been shown to have negative correlations with Machiavellianism. Additionally, research has shown that Machiavellianism is unrelated to a more advanced theory of mind, that is, the ability to anticipate what others are thinking in social situations. However, research results have suggested the contrary viewpoint that high Machiavellianism is associated with excellent theory of mind skills.
When it comes to manipulation, individuals high in Machiavellianism may, according to Bereczkei, "have certain cognitive and social skills that enable them to properly adapt to the challenges of environmental circumstances". They also are incredibly perceptive to the presence of others, and are able to feign altruism to enhance their reputation. A recent study investigated whether Machiavellianism is associated with the production of "bullshit", which is defined as inaccurate or meaningless information intended to impress, persuade or mislead. The researchers found that the manipulative aspect of Machiavellianism (Machiavellian approach) was linked to "persuasive bullshitting", aimed at gaining desired resources. The distrustful aspect (Machiavellian avoidance) was associated with "evasive bullshitting", spreading vague information to prevent disadvantages. Those high in Machiavellian avoidance were even better at distinguishing misinformation from valuable information.
Neurological studies
There have been few studies on the neural correlates of Machiavellianism. Research has shown that Machiavellianism has been correlated with changes in gray matter in the areas of the basal ganglia, left prefrontal cortex, bilaterally in the insula, and in the right hippocampus and the left parahippocampal gyrus. Researcher Tamas Bereczkei stated that the manipulation skill in High Machs is associated with neural correlates that are responsible for decision making. He also noted that behaviors associated with Machiavellianism need to "recruit more neural resources than a honest behavior, especially when manipulators face a cooperative partner as a potential victim. Machiavellians have to inhibit the norm of reciprocity and, additionally, generate an opposite response." Machiavellianism has also been linked with lesions in the left dorsolateral prefrontal cortex. Frontal dysfunction was also linked with Machiavellianism. Daniel Jones also concluded that those who score high on Machiavellianism have the "neurological structure of a strategic manipulator". The activation of the task-positive network (TPN) and the default mode network (DMN) have also been associated with a lack of genuine empathy, and also have been observed in Machiavellianism. A recent study linked regional gray matter volume in the left superior frontal gyrus to both Machiavellianism and social aggression, which is "intentional antisocial behavior directed to damage others’ social reputations or interpersonal relationships through socially manipulative tactics".
Social relationships
The effects that one's level of Machiavellianism has on a person's socialization and interpersonal relationships, such as friendships and romantic relationships, has been studied extensively. High Machs are highly likely to ingratiate themselves within social groups via compliments and conforming their opinions to those around them.
High Machs are more than likely to choose better quality friends, as they have a better time at guessing who is a good person and thus more pliable for manipulation. Machiavellianism was also correlated with withdrawal and avoidance in romantic relationships. Individuals high in all dark triad traits find it easy to end relationships, and tend to prefer short-term relationships over long term ones. Studies done on courtship showed that women higher on machiavellianism tend to go on dates not for sexual reasons but for free food, a phenomenon known as a "foodie call". Because a lack of empathy and affect with regards to others is one of the main features of Machiavellianism, individuals high on the trait tend to act in a utilitarian, self interested manner, prefer emotionally detached relationships, and are not concerned with the other person's needs. High machs report lower relationship satisfaction than those lower on the scale.
Though there has been research on the potential "attractiveness" of the dark triad traits, out of all of the traits in the dark triad, Machiavellianism was the least attractive to the opposite sex. One of the studies concluded that "The third DT trait, Machiavellianism, was significantly negatively associated with being chosen and mate appeal for STR (short term relationships) in women." Another study claimed that this was because high Machs tend to be way less extroverted than narcissists and psychopaths, and that "it is possible that individuals do not like cynical, manipulative, aggressive, remorseless, and duplicitous people such as Machiavellians and psychopaths".
Like the other dark triad traits, those high on Machiavellianism have been reportedly more willing to troll or flame others on the internet, however a 2021 study found no particularly strong connection between trolling and dark personality traits. Machiavellianism has also been correlated with a higher than average belief in conspiracy theories. Because of their emphasis on hierarchy, high scorers in Machiavellianism were also found with higher levels of prejudice, and higher social dominance orientation scores.
Gender differences
Research has consistently shown that men score higher than women in Machiavellianism. There is evidence to suggest that Machiavellianism is represented differently in both sexes, with men being more opportunistic, self confident, and willing to take risks, while women higher in Machiavellianism are more likely to be avoidant and have anxious features. While only psychopathy was an indicator of future infidelity amongst men, both psychopathy and Machiavellianism were predictors amongst women. The findings of one research paper showed that men, but not women, high in Machiavellianism were non-impulsive and high in planning, which suggests that the apparent impulsivity of Machiavellianism may be a question of gender. Peter Jonason suggested that the reason why men score much higher than women in dark triad traits is because men require less emotional connection in order to get ahead in life.
Cross-cultural studies
There have been many studies on how Machiavellianism is presented in people from different countries and with different cultures. Multiple studies found that in nearly all countries, men scored higher than women in Machiavellianism, and that the gender differences were notable. The populations of many other countries varied from their western counterparts in their levels of dark triad traits overall, which the authors of one study attributed to sociopolitical factors and levels of economic engagement. In another cross cultural study, Machiavellianism also showed associations with limited interactive or normative values. A study investigated the relationship between emotion recognition and dark personality traits (including Machiavellianism) across cultures. The effects were gender and culture-dependent. Among both German males and females, Machiavellianism showed strong positive associations with emotionally manipulative tactics. Some scholars noted an issue with many cross cultural studies on machiavellianism, primarily that "researchers have used measures of Machiavellianism (Mach IV) which were derived from Western concepts and which may not have similar meanings when applied to non-Western groups."
Aggression and antisocial behavior
Machiavellianism has little association with the outright display of aggression. Those high in Machiavellianism tend to be more aggressive to short term as opposed to long-term partners. While Machiavellianism is associated with hostility, those high on the trait may mask it depending on the manipulation tactic used. Machiavellianism also is associated with the tuning of aggression to the benefit long-term objectives, only engaging in antisocial behavior when the stakes are low and it proffers benefits, unlike psychopathy and narcissism. In a study by Delroy Paulhus and Daniel Jones, High Machs were found to refrain from cheating under risky situations, preferring to sustain their reputation for the long term than to engage in short-term financial gain. The authors then state that High Machs may cheat under high risk scenarios, but only when "ego-depleted", which then makes their behavior appear similar to those of psychopaths. McHoskey found that MACH is associated with "cheating, divulging intimate sexual secrets to third parties, and both feigning love and inducing intoxication to secure sex". He also suggested that Machiavellianism is correlated with an extensive focus on financial gain, and is also correlated with antisocial behaviors such as stealing, vandalism, and cheating as opposed to prosocial actions like helping others.
In the workplace
Machiavellianism is also studied by organizational psychologists, especially those who study manipulative behaviors in workplace settings. Workplace behaviors associated with this concept include flattery, deceit, coercion, and the abuse of others through one's position of leadership. These behaviors in the workplace are ultimately done to advance personal interests. Individuals high dark traits in general show mixed relations with workplace success, with some being successful, and some falling behind.
Individuals high in machiavellianism tend to gravitate towards particular careers, especially those that require a high degree of competitiveness needed to succeed. High Machs are ambitious enough to cut corners and use aggressive means if it is necessary to get ahead in their careers. It was shown that those high on Machiavellianism are more drawn to academic majors like economics, law, and politics, as opposed to the "person-oriented" majors like education, nursing, and social work that were associated with lower Machiavellianism scores.
High levels of Machiavellianism negatively affect subordinates' career success and well-being. Individuals high in MACH found it easier to obtain leadership positions, and a better salary. Machiavellianism was identified as a significant moderator in the relationship between perceptions of both adhocracy and hierarchy cultures and bullying victimization. The positive impact of ethical leadership can possibly be diminished with leaders who score highly on MACH.
Scale evaluation
Dimensions of the MACH scale
Although there have been a multitude of proposed factor structures, two dimensions emerge most consistently within factor-analytic research which separates the views from the behaviors in Machiavellianism. Although many posit that the Mach IV scale is unable to reliably capture the two dimensions, a 10-item subset of the scale known as the "two-dimensional Mach IV" (TDM-V), reproduces the views and tactics dimensions across countries, genders, sample types, and scale category length. The "Views" dimension appears to capture the neurotic, narcissistic, pessimistic, and distrustful aspects of Machiavellianism, while the "Tactics" component captures the more unconscientious, self-serving, and deceitful behavioral aspects. More recently, in response to criticisms of the Mach-IV, researchers developed the Five-Factor Machiavellianism Inventory (FFMI), which attempts to include concepts (like being calculated and planful) that are not adequately captured by the Mach-IV.
Construct validity and criticism
There has been debate on how valid Machiavellianism scales are in tapping the construct. It is often stated by those critical of Machiavellianism scales that it does not actually measure the theoretical trait, but something identical to psychopathy and narcissism. For example, it is often stated that Machiavellianism is marked by less impulsivity and better long term thinking as opposed to psychopathy, but some empirical research shows that even High Machs can act impulsive in certain scenarios. Lynam and others stated "we suggest that existing measures of Machiavellianism are functioning as proxy measures of psychopathy." Psychologist John Rauthmann viewed the MACH-IV as more of a measure of cynicism, and that it doesn't really capture other qualities of Machiavellianism.
Most of the research done on Machiavellianism has been done with either the Mach IV or Mach V, though the Mach V is no longer in use due to psychometric issues. Many have expressed concerns with the reliability of the Mach IV scale to capture all of the features of Machiavellianism, thus many proposals have been made in favor of other Machiavellianism scales.
John Rauthmann and others have stated that, while the MACH-IV is "a generally reliable and valid scale", it has its shortcomings. These include the response styles of the test takers, the varying factor structures, and "insufficient content and construct validity". The researchers developed their own scale instead to study Machiavellianism multidimensionally instead of unidimensionally to prevent the construct from becoming hard to study effectively. Psychologist Jason Dahling and others have created another measure of Machiavellianism, dubbed the Machiavellian Personality Scale (or MPS for short).
Daniel Jones has stated that the MACH IV, despite all of its merits, is an "outdated instrument" and "is not helping the field with precision". He ultimately states that it "should be replaced by assessments that are more precise reflections of the construct." Scholars note that there is a tendency to conflate the scale with Machiavelli's ideas, even though it has zero relation to the historical figure or his political works. Regarding the MACH-IV, recent scholars have stated that almost all of items on the scale attributed to Machiavelli do not come from him, with only one item (item 20) corresponding somewhat to his actual writings. Also, two items on the MACH-IV reference P.T. Barnum (born 1810) and voluntary euthanasia, both of which are unrelated to Machiavelli's ideas.
Application of the scale in other research
In 2002, the Machiavellianism scale of Christie and Geis was applied by behavioral game theorists Anna Gunnthorsdottir, Kevin McCabe and Vernon L. Smith in their search for explanations for specific behavior in experimental games, especially individual choices which do not correspond to assumptions of material self-interest captured by the standard Nash equilibrium prediction. It was found that in a trust game, those with high Mach-IV scores tended to follow Homo economicus equilibrium strategies while those with low Mach-IV scores tended to deviate from the equilibrium, and instead made choices that reflected widely accepted moral standards and social preferences. In one study, Machiavellianism was positively associated with making economically opportunistic decisions in order to maximize overall profit. Levels of the trait were also an influence on the level of trust an individual had in regards to another person's motives. The authors go on to explain that the use of "cooperative or defecting strategies is subject to important individual differences".
A study done by David Wilson and other researchers noted that while High Machs tend to defect from their groups, they are also unlikely to succeed in the long term simply by manipulating others, and that some cooperation is necessary for further success and to avoid a situation in which they are retaliated against. Wilson also noted that since those who are high in Machiavellianism often come across as charming and attractive in brief social encounters, it is unclear whether they are being deceitful or just very skilled socially. The researchers had people who scored high and low on Machiavellianism write first-person stories. Other participants then evaluated these stories. The results showed that people with low Machiavellianism tended to be more cooperative, while those with high Machiavellianism were more exploitative. Based on these stories, high Machs were generally rejected as social partners, except when their manipulative skills could be used against members of other groups.
See also
Dark Triad Dirty Dozen
Dark Factor of Personality
Amorality
References
Sources
External links
All existing literature related to Machiavellianism on Google Scholar
Literature related to Machiavellianism on JSTOR
American Psychological Association's Dictionary entry on Machiavellianism
Machiavellianism- Encyclopædia Britannica
Machiavellianism overview in Psychology Today
Interactive MACH IV test on the Open-Source Psychometrics Project
Dark triad
Personality
Personality traits | Machiavellianism (psychology) | [
"Biology"
] | 11,428 | [
"Behavior",
"Personality",
"Human behavior"
] |
61,853,234 | https://en.wikipedia.org/wiki/Sigbritt%20Karlsson | Sigbritt Karlsson (31 January 1958 – 28 October 2023) was a Swedish chemical engineer and president of KTH Royal Institute of Technology between November 2016 and November 2022.
Karlsson earned a master of science in chemical engineering with a specialization in biotechnology from KTH. She subsequently completed a PhD in polymer technology.
From 1996 to 2004 Karlsson worked as Director of Studies at KTH. Between 2008 and 2010 she was Vice Dean with responsibility for strategic education issues.
Karlsson was Vice-Chancellor of the University of Skövde 2010–2016. On November 12, 2016, she became the 19th President of KTH Royal Institute of Technology.
References
1958 births
2023 deaths
Swedish chemical engineers
Women chemical engineers
21st-century Swedish chemists
Women heads of universities and colleges
Rectors of KTH Royal Institute of Technology
Swedish women engineers
20th-century Swedish women engineers
21st-century Swedish women engineers
20th-century Swedish engineers
21st-century Swedish engineers | Sigbritt Karlsson | [
"Chemistry"
] | 192 | [
"Women chemical engineers",
"Chemical engineers"
] |
61,853,921 | https://en.wikipedia.org/wiki/Chen%20Hu%20%28physician%29 | Chen Hu (; 17 February 1962 – 24 July 2019) was a Chinese military physician and stem cell researcher. He served as Director of the PLA Institute of Hematopoietic Stem Cell Research and the Beijing Hematopoietic Stem Cell Therapy Laboratory. Known for his research on hematopoietic stem cell therapy for leukemia, he was awarded the State Science and Technology Progress Award (First Class) in 2015 and the Ho Leung Ho Lee Prize in 2016. In 2017, he and Deng Hongkui engineered resistance to HIV in mice using CRISPR gene editing, and for the first time used the technique on an AIDS patient. He died of a sudden heart attack before their findings were published.
Biography
Chen Hu was born 17 February 1962 in Chongqing, China, with his ancestral home in Luoyang, Henan. He enlisted in the People's Liberation Army (PLA) in September 1979 and enrolled at the Third Military Medical University (now Army Medical University). He earned both a Ph.D. and an M.D.
After graduation, Chen became a physician at the Affiliated Hospital of the Academy of Military Medical Sciences. He later served as Director of the Beijing Hematopoietic Stem Cell Therapy Laboratory and Director of the PLA Institute of Hematopoietic Stem Cell Research at the Fifth Medical Center (formerly the 307 Hospital) of the People's Liberation Army General Hospital in Beijing.
Chen spent more than 30 years researching treatment for leukemia, with a focus on hematopoietic stem cell (HSC) therapy. He treated more than 40,000 patients and performed over 3,200 HSC transplants, improving the survival rate from nearly 0% at the beginning to 65%. In 2015, his research on the treatment of radiation damage using adult stem cells won the State Science and Technology Progress Award (First Class). A year later, he won the Ho Leung Ho Lee Prize for Science and Technology Progress.
In 2017, Chen and his collaborator, Deng Hongkui of Peking University, used CRISPR gene editing to transplant human HSCs with the edited CCR5 gene to mice, and conferred HIV resistance to the animals. They subsequently used the technique to treat an AIDS patient who suffered from acute lymphoblastic leukemia (ALL). It was the first time CRISPR was used on a human HIV patient. 19 months later, the patient's ALL was in complete remission. Their research demonstrated the safety of CRISPR for humans, although the therapy was not effective for curing AIDS as only 5% to 8% of the patient's bone marrow cells carried the edited CCR5 gene, much lower than the ideal 100%. Their research was published in The New England Journal of Medicine in September 2019, after Chen had died.
On 24 July 2019, Chen Hu died from a sudden heart attack in Beijing, aged 57. At the time of his death he was a candidate for election to the Chinese Academy of Sciences.
References
1962 births
2019 deaths
20th-century Chinese physicians
21st-century Chinese physicians
Biologists from Chongqing
Cancer researchers
Chinese medical researchers
Chinese military doctors
Stem cell researchers
Burials at Babaoshan Revolutionary Cemetery | Chen Hu (physician) | [
"Biology"
] | 643 | [
"Stem cell researchers",
"Stem cell research"
] |
61,854,053 | https://en.wikipedia.org/wiki/Metal%20assisted%20chemical%20etching | Metal Assisted Chemical Etching (also known as MACE) is the process of wet chemical etching of semiconductors (mainly silicon) with the use of a metal catalyst, usually deposited on the surface of a semiconductor in the form of a thin film or nanoparticles. The semiconductor, covered with the metal, is then immersed in an etching solution containing an oxidizing agent and hydrofluoric acid. The metal on the surface catalyzes the reduction of the oxidizing agent and therefore in turn also the dissolution of silicon. In the majority of the conducted research this phenomenon of increased dissolution rate is also spatially confined, such that it is increased in close proximity to a metal particle at the surface. Eventually this leads to the formation of straight pores that are etched into the semiconductor (see figure to the right). This means that a pre-defined pattern of the metal on the surface can be directly transferred to a semiconductor substrate.
History of development
MACE is a relatively new technology in semiconductor engineering and therefore it has yet to be a process that is used in industry. The first attempts of MACE consisted of a silicon wafer that was partially covered with aluminum and then immersed in an etching solution. This material combination led to an increased etching rate compared to bare silicon. Often this very first attempt is also called galvanic etching instead of metal assisted chemical etching.
Further research showed that a thin film of a noble metal deposited on a silicon wafer's surface can also locally increase the etching rate. In particular, it was observed that noble metal particles sink down into the material when the sample is immersed in an etching solution containing an oxidizing agent and hydrofluoric acid (see image in the introduction). This method is now commonly called the metal assisted chemical etching of silicon.
Other semiconductors were also successfully etched with MACE, such as silicon carbide or gallium nitride. However, the main portion of research is dedicated to MACE of silicon.
It has been shown that both noble metals such as gold, platinum, palladium, and silver, and base metals such as iron, nickel, copper, and aluminium can act as a catalyst in the process.
Theory
Some elements of MACE are commonly accepted in the scientific community, while others are still under debate. There is agreement that the reduction of the oxidizing agent is catalyzed by the noble metal particle (see figure to the left). This means that the metal particle has a surplus of positive charge which is eventually transferred to the silicon substrate. Each of the positive charges in the substrate can be identified as a hole (h+) in the valence band of the substrate, or in more chemical terms it may be interpreted as a weakened Si-Si bond due to the removal of an electron.
The weakened bonds can be attacked by a nucleophilic species such as HF or H2O, which in turn leads to the dissolution of the silicon substrate in close proximity to the noble metal particle.
From a thermodynamic point of view, the MACE process is possible because the redox potential of the redox couple corresponding to the used oxidizing agents (hydrogen peroxide or potassium permanganate) are below the valence band edge at the electrochemical energy scale. Equivalently, one could say that the electrochemical potential of the electron in the etching solution (due to the presence of oxidizing agent) is lower than the electrochemical potential of the electron in the substrate, hence electrons are removed from the silicon. In the end, this accumulation of positive charge leads to the dissolution of the substrate by hydrofluoric acid.
MACE consists of multiple individual reactions. At the metal particle, the oxidizing agent is reduced. In the case of hydrogen peroxide this can be written down as follows:
H2O2 + 2H+ -> 2H2O + 2h+
The created holes (h+) are then consumed during the dissolution of silicon. There are several possible reactions via which the dissolution can take place, but here just one example is given:
Si + 6HF + 4h+ -> SiF6^{2}- + 6H+
There are still some unclear aspects of the MACE process. The model proposed above requires contact of the metal particle with the silicon substrate which is somehow conflicting with the etching solution being underneath the particle. This can be explained with a dissolution and redeposition of metal during MACE. In particular it is proposed, that some metal ions from the particle are dissolved and eventually are re-deposited at the silicon surface with a redox reaction. In this case the metal particle (or even larger noble metal thin films) could partially maintain contact to the substrate while also etching could partially take place underneath the metal.
It is also observed that in the vicinity of straight pores as shown in the introduction also a micro-porous region between the pores is formed. Generally this is attributed to holes that diffuse away from the particle and hence contribute to etching at more distant locations.
This behavior is dependent on the doping type of substrate as well as on the type of noble metal particle. Therefore, it is proposed that the formation of such a porous region beneath the straight pores depends on the type of barrier that is formed at the metal/silicon interface. In the case of an upward band bending the electric field in the depletion layer would point towards the metal. Therefore, holes cannot diffuse further into the substrate and thus no formation of a micro-porous region is observed. In the case of downward band-bending holes could escape into the bulk of the silicon substrate and eventually lead to etching there.
Experimental procedure of MACE
As already stated above MACE requires metal particles or a thin metal thin film on top of a silicon substrate. This can be achieved with several methods such as sputter deposition or thermal evaporation. A method to obtain particles from a continuous thin film is thermal dewetting.
These deposition methods can be combined with lithography such that only desired regions are covered with metal. Since MACE is an anisotropic etching method (etching takes place not in all spatial directions) a pre-defined metal pattern can be directly transferred into the silicon substrate.
Another method of depositing metal particles or thin films is electroless plating of noble metals on the surface of silicon. Since the redox potentials of the redox couples of noble metals are below the valence band edge of silicon, noble metal ions can (like described in the theory section) inject holes (or extract electrons) from the substrate while they are reduced. In the end metallic particles or films are obtained at the surface.
Finally, after the deposition of the metal on the surface of silicon, the sample is immersed in an etching solution containing hydrofluoric acid and oxidizing agent. Etching will take place as long as the oxidizing agent and the acid are consumed or until the sample is removed from the etching solution.
Applications of MACE
The reason why MACE is heavily researched is that it allows completely anisotropic etching of silicon substrates which is not possible with other wet chemical etching methods (see figure to the right). Usually the silicon substrate is covered with a protective layer such as photoresist before it is immersed in an etching solution. The etching solution usually has no preferred direction of attacking the substrate, therefore isotropic etching takes place. In semiconductor engineering, however it is often required that the sidewalls of the etched trenches are steep. This is usually realized with methods that operate in the gas-phase such as reactive ion etching. These methods require expensive equipment compared to simple wet etching. MACE, in principle allows the fabrication of steep trenches but is still cheap compared to gas-phase etching methods.
Porous silicon
Metal assisted chemical etching allows for the production of porous silicon with photoluminescence.
Black silicon
Black silicon is silicon with a modified surface and is a type of porous silicon. There are several works on obtaining black silicon using MACE technology. The main application of black silicon is solar energy.
Black Gallium Arsenide
Black Gallium Arsenide with light trapping properties have been also produced by MACE.
References
Etching
Chemistry
Research lasers
Semiconductors
Engineering | Metal assisted chemical etching | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 1,697 | [
"Electrical resistance and conductance",
"Physical quantities",
"Semiconductors",
"Materials",
"Electronic engineering",
"Condensed matter physics",
"Solid state engineering",
"Matter"
] |
61,857,932 | https://en.wikipedia.org/wiki/Kitboga%20%28streamer%29 | Kitboga is the Internet alias of an American Twitch streamer and YouTuber whose content primarily focuses on scam baiting against phone fraud. His channel has over one million followers on Twitch, and his YouTube channel has over three million subscribers.
Career
Scambaiting
In mid-2017, Kitboga found out that his grandmother had fallen victim to many scams designed to prey on the elderly, both online and in person. He then discovered "Lenny", a loop of vague pre-recorded messages that scam baiters play during calls to convince the scammer that there is a real person on the phone without providing any useful information to the scammer. After seeing these videos uploaded to YouTube, he decided to replicate the calls himself. While he started out streaming for his friends on Twitch, his viewership soon started growing beyond his immediate circles. Kitboga hopes that by wasting scammers' time, he can prevent them from scamming others, while also providing entertainment and education to his viewers.
In March 2020, with the growing prevalence of the COVID-19 pandemic, Kitboga started baiting scammers who were selling an essential oil which they dishonestly claimed was a cure for COVID-19, following a United States Federal Trade Commission warning alerting consumers of coronavirus-related scams.
In November 2020, Kitboga was signed by talent agency UTA. In May 2022, Kitboga was signed by Ryan Morrison's Evolved Talent Agency, again to expand Kitboga's goal of anti-scam messaging.
In February 2023, Kitboga began working with AnyDesk, the creator of the remote desktop software often used by scammers. AnyDesk's aim is to stop its software being used for fraud. While scambaiting, if a scammer uses AnyDesk as their remote desktop software, Kitboga could give an AnyDesk representative the current connection ID number, and in turn, AnyDesk can track and ban all scammers' devices from using AnyDesk within the same network.
In May 2023, Kitboga has partnered with Kraken, a cryptocurrency exchange, to create a spoof Kraken account to trap scammers into giving wallet addresses from stolen crypto accounts, along with their personally identifiable information should they decide to sign up for an account.
Technique
In his videos, Kitboga engages in scam baiting with several types of scammers. Besides technical support scammers, he also engages with refund scammers, IRS scammers, social security scammers, and others. He mixes elements of popular culture into his dialogue and wordplay into some calls; for example, in one March 2020 call against a scammer falsely claiming to sell a COVID-19 cure, Kitboga implied the scammer should be called "Saint Anne", eliding the two words to sound like "Satan".
To misdirect scammers away from his real identity, as well as for viewer entertainment, Kitboga often poses as many different characters during his videos, including an elderly woman or man, a Russian man named Vicktor Viktoor, a valley girl named Nevaeh ("Heaven" spelled backward), or a competing technical support scammer named Daniel. He does this by imitating the accent or vocal intonation of the character he is trying to portray, often with a voice changer to alter the pitch of his voice. The common factor uniting Kitboga's characters is that they are not computer-savvy, giving the scammer confidence that the scam is more likely to succeed.
The scams against which Kitboga engages in scambaiting often require the victim to install remote desktop software. As an example, in the case of technical support scams, the scammers request access to the victim's computer to "diagnose" a technical issue (where none exists), for which they then request payment to "fix". Because of the risks involved in remotely connecting to an unknown computer, Kitboga uses a different computer than his while scambaiting; the computer runs a virtual machine equipped with a virtual private network. This ensures not only that any malware or other software installed by the scammer does not affect his computer, but also hides his true IP address and location from the scammers. However, scammers can sometimes discern when a potential victim is using a virtual machine, so Kitboga and his team "have spent countless hours 'spoofing' [their] virtual machine to look and feel like a well-used, average computer."
Types of phone scams other than the technical support scam also often involve the scammer giving some reason to connect to the victim's computer. In online refund scams, for example, the scammer requests to connect to the victim's computer to access their online banking website. When Kitboga interacts with these scammers, in addition to taking the aforementioned precautions, he also uses a fake online banking website he created specifically for use in this type of scambaiting. This website contains intentional features and Easter eggs that make it more difficult for the scammer to conduct the scam, both so that the scammer wastes additional time and for the entertainment of Kitboga's audience.
When baiting IRS scammers and other types of scammers that request payments via gift card, Kitboga uses a piece of computer code to make the gift card redemption page accept any gift code that follows a specified format. Then, when the scammer asks him to read out the gift codes so they can redeem them to take payment from the victim, he types them into his own computer and claims them himself, pretending not to know any better.
At the end of bait calls, Kitboga sometimes turns off his voice changer and reveals that he has been aware that the call was an attempted scam the entire time. Some of the scammers immediately hang up when Kitboga reveals the ruse to them. Others' reactions to this range from anger to regret, with some maintaining that they are legitimate tech support agents. Still others are unrepentantly dismissive of Kitboga's hoax, informing him that plenty of impending victims yet await on hold. In later installments Kitboga has largely moved away from revealing his true nature, for two main reasons: one being that the scammer reaction is often either to pretend to have known all along or hang up, and the other being that he finds it more entertaining to leave the scammer believing that they failed to steal from an actual potential victim.
Other work
Kitboga has actively promoted computer science education. He regularly holds computer programming streams where he maintains some of the tools he uses in his scambaiting calls. Kitboga partnered with the STEM organization FIRST in 2018 to stream the building of a real-life "meme-o-meter" as used in his scambaiting streams; during the stream, he interacted with children interested in STEM through the stream chat. He stated in 2021 that he was looking into building an AI scambaiting program.
Before starting his Twitch and YouTube channels, Kitboga worked in software engineering, and used his technical background and knowledge of virtual machines to protect himself while scambaiting. He has said that if more people become aware of the scams he tries to bait, decreasing their prevalence, he will consider returning to software engineering or changing the focus of his stream to coding or playing video games.
In December 2023, Kitboga and his team launched a new company called Seraph Secure. This company provides software that helps prevent scams, including blocking scammer connections, blocking scam websites, and sending alerts to users when a threat is detected on a victim's computer. This software is currently only supported on Windows 10/11 and will include support for MacOS, iOS, and Android in the future.
Awards and nominations
See also
References
External links
English-language YouTube channels
American Twitch (service) streamers
Unidentified people
Hackers
Hacking in the 2010s
Hacking in the 2020s
Technology YouTubers
Social engineering (security)
Internet vigilantism
YouTube channels launched in 2017
Year of birth missing (living people)
Living people | Kitboga (streamer) | [
"Technology"
] | 1,734 | [
"Lists of people in STEM fields",
"Hackers"
] |
52,956,308 | https://en.wikipedia.org/wiki/Fluxion | A fluxion is the instantaneous rate of change, or gradient, of a fluent (a time-varying quantity, or function) at a given point. Fluxions were introduced by Isaac Newton to describe his form of a time derivative (a derivative with respect to time). Newton introduced the concept in 1665 and detailed them in his mathematical treatise, Method of Fluxions. Fluxions and fluents made up Newton's early calculus.
History
Fluxions were central to the Leibniz–Newton calculus controversy, when Newton sent a letter to Gottfried Wilhelm Leibniz explaining them, but concealing his words in code due to his suspicion. He wrote:
The gibberish string was in fact a hash code (by denoting the frequency of each letter) of the Latin phrase Data æqvatione qvotcvnqve flventes qvantitates involvente, flvxiones invenire: et vice versa, meaning: "Given an equation that consists of any number of flowing quantities, to find the fluxions: and vice versa".
Example
If the fluent is defined as (where is time) the fluxion (derivative) at is:
Here is an infinitely small amount of time. So, the term is second order infinite small term and according to Newton, we can now ignore because of its second order infinite smallness comparing to first order infinite smallness of . So, the final equation gets the form:
He justified the use of as a non-zero quantity by stating that fluxions were a consequence of movement by an object.
Criticism
Bishop George Berkeley, a prominent philosopher of the time, denounced Newton's fluxions in his essay The Analyst, published in 1734. Berkeley refused to believe that they were accurate because of the use of the infinitesimal . He did not believe it could be ignored and pointed out that if it was zero, the consequence would be division by zero. Berkeley referred to them as "ghosts of departed quantities", a statement which unnerved mathematicians of the time and led to the eventual disuse of infinitesimals in calculus.
Towards the end of his life Newton revised his interpretation of as infinitely small, preferring to define it as approaching zero, using a similar definition to the concept of limit. He believed this put fluxions back on safe ground. By this time, Leibniz's derivative (and his notation) had largely replaced Newton's fluxions and fluents, and remains in use today.
See also
History of calculus
Newton's notation
Hyperreal number: A modern formalization of the reals that includes infinity and infinitesimals
Nonstandard analysis
References
Mathematical analysis
Differential calculus
History of calculus | Fluxion | [
"Mathematics"
] | 545 | [
"Mathematical analysis",
"Calculus",
"Mathematics of infinitesimals",
"Differential calculus",
"History of calculus"
] |
52,956,464 | https://en.wikipedia.org/wiki/EROSITA | eROSITA is an X-ray instrument built by the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany. It is part of the Russian–German Spektr-RG space observatory, which also carries the Russian telescope ART-XC. It was launched by Roscosmos on 13 July 2019 from Baikonur, and deployed in a 6-month halo orbit around the second Lagrange point (L2). It began collecting data in October 2019. Due to the breakdown of institutional cooperation between Germany and Russia after the invasion of Ukraine, the instrument stopped collecting data on February 26, 2022.
Overview
eROSITA was originally designed by the ESA for the International Space Station, and it was concluded in 2005 that its accommodation on a dedicated free flyer would provide significantly improved scientific output. The eROSITA telescopes are based on the design of the ABRIXAS observatory launched in April 1999, whose battery was accidentally overcharged and destroyed three days after the mission started.
The plan was eROSITA imaging the entire sky in the X-ray band for seven years. The eROSITA all-sky survey (eRASS) was the first image of the entire sky in the 2-10 keV band. In the 0.3-2 keV band, it is expected to be 25 times more sensitive than the pioneering ROSAT mission of the 1990s, and will effectively supersede it. eROSITA is expected to detect 100,000 galaxy clusters, 3 million active galactic nuclei and 700,000 stars in the Milky Way. The primary science goal is to measure dark energy through the structure and history of the Universe traced by galaxy clusters.
eROSITA was launched on 13 July 2019 by Roscosmos from Baikonur. It achieved first light on 17 October 2019 and completed its first all-sky survey on 11 June 2020. In the summer of 2021 the first eROSITA X-ray data release to the public was announced. The operations of eROSITA were suspended on 26 February 2022 after the Russian attack into Ukraine. The science operations of the instrument were paused, but the analysis of the data already received in Germany continued. At the time, eROSITA had completed four of its planned eight full-sky surveys. In June 2022, Roscosmos announced its intent to restore the operation of eROSITA unilaterally, which was criticized by experts for its potential to damage the telescope.
Construction
The telescope consists of seven identical Wolter-type mirror modules with 54 nested gold-coated mirrors. The mirrors are arranged to collect the high-energy X-ray photons and guide them to the eROSITA X-ray sensitive cameras. The cameras were also custom-built at MPE, with X-ray CCDs manufactured from high-purity silicon. For optimum performance, the cameras are cooled to .
Instruments
Collaboration
eROSITA was developed at the Max Planck Institute for Extraterrestrial Physics in collaboration with institutes in Bamberg, Hamburg, Potsdam und Tübingen. The instrument principal investigator is Peter Predehl. The project scientist is Andrea Merloni. The German eROSITA consortium has members from institutes all across Germany, but also from international institutes, and has established collaborations with ground-based telescopes for follow-up observations of the millions of sources that will be detected by eROSITA.
Science results
First science verification results were released on October 22, 2019, including high-resolution spectra of Supernova 1987a, images of the Large Magellanic Cloud and galaxy clusters, as well as light curves of a highly variable Active Galactic Nuclei.
The first all-sky survey was completed on June 11, 2020, cataloging 1.1 million sources, including mostly Active Galactic Nuclei (77%), stars with strong, magnetically active hot coronae (20%) and clusters of galaxies (2%), but also bright X-ray binaries, supernova remnants, extended star-forming regions as well as transients such as Gamma-Ray Bursts. The map includes extended features of the Milky Way, including mushroom-like bubbles and absorbing galactic gas in the disk (blue).
See also
Fermi Gamma-ray Space Telescope
References
External links
Home page of eROSITA
Nature news article
eROSITA science book
Simulations of the expected X-ray sky
Project news on Twitter
Video animation
Space telescopes
X-ray telescopes | EROSITA | [
"Astronomy"
] | 895 | [
"Space telescopes"
] |
52,956,862 | https://en.wikipedia.org/wiki/Immunologic%20constant%20of%20rejection | The Immunologic Constant of Rejection (ICR), is a notion introduced by biologists to group a shared set of genes expressed in tissue destructive-pathogenic conditions like cancer and infection, along a diverse set of physiological circumstances of tissue damage or organ failure, including autoimmune disease or allograft rejection. The identification of shared mechanisms and phenotypes by distinct immune pathologies, marked as a hallmarks or biomarkers, aids in the identification of novel treatment options, without necessarily assessing patients phenomenologies individually.
Concept
The concept of immunologic constant of rejection is based on the proposition that:
Tissue-specific destruction does not necessarily only occur after non-self recognition of the body, but can also occur against self- or quasi-self; such as the phenotypes observed in autoimmune diseases.
Immune cells required for the induction of a cognate/adaptive immune response differ from those cells necessary for the activation of an effector immune response.
Although the causes of tissue-specific destruction vary among pathologic states, the effector immune response observed in these conditions is found to converge into one single mechanism, including the activation of adaptive and innate cytotoxic mechanisms.
Adaptive immunity participates as a tissue-specific trigger, but it is not always sufficient or necessary for tissue destruction. Intensive work on factors activated during immune-mediated rejection have concluded that tissue-specific destruction is correlated with the expression of interferons (IFNa and IFNy), and Interferon-stimulated gene (ISGs).
Mechanism
In the case of autoimmunity and/or allograft rejection, immunity broadens in the target organ by producing chemokines of the CXCL family that recruit the receptor CXCR3-bearing cytotoxic T cells. These initiate the following cascade:
CXCR3 ligand chemokines (CXCL-9, -10 and -11) are produced in response to activated B cells and the pro-inflammatory secretion of interleukin 12 (IL12) and/or interferon-gamma (IFNy) by antigen-presenting cells (APCs).
CXCR3 expressing Th1-polarized CD4 T cells and cytotoxic T cells are recruited to the site of acute inflammation.
Antigen-activated T cells secrete CCR5 ligands (CCL2 and CCL3) to recruit natural killer (NK) cells and other innate immune effector cells to the site of acute inflammation.
Several cytotoxic mechanisms converge on the target tissue, and its complete destruction occurs through the activated effects of CTLs, NK cells, granulocytes, macrophages and dendritic cells.
As such, 20 genes involved in this cascade make up the ICR gene set, including:
T helper type 1 (Th1) cell-related factors such as IFNy, signal transducers and activator of transcription 1 (STAT1), IL12B, Interferon-regulatory factor 1 (IRF1), the transcription factor T-bet (TBX21).
CD8 Tcell markers : CD8A & CD8B
Immune effector or cytotoxic factors like the granzymes GZMA, GZMB, GZMH, perforin PRF1, and granulysin GNLY.
Chemokine ligands CXCL9, CXCL10, and CCL5 that bind to chemokine receptors such as CXCR3 and CCR5,
Immune suppressive or counter regulatory genes like IDO1, PDCD1, PDL1 (CD274), CTLA4 and FOXP3
Clinical significance
Cancer
The disrupted homeostasis of cancer cells is found to initiate processes promoting cell growth. To illustrate, growth factors and chemokines activated in response to injury are recruited by tumour cells, sustaining chronic inflammation; similarly to the immune phenotype found in chronic infection, allograft rejection and autoimmunity diseases. The role of immunity in cancer is demonstrated by the predictive and prognostic role of tumour-infiltrating lymphocytes (TIL) and immune response gene signatures. In several cancers these genes show great correlation. A high expression of these genes indicates an active immune engagement, and at least a partial rejection of the cancer tissue.
Breast Cancer
In breast cancer increased survival is observed in patients displaying a high level of ICR gene expression. This immune active phenotype was associated with an increased level of mutations while the poor immune phenotype was defined by perturbation in the MAPK signalling pathways.
The consensus clustering of tumours based on ICR gene expression provides an assessment of the prognosis and response to immunotherapy. To illustrate, classification of breast cancer into four classes (ranking from ICR4 to ICR1) have shown better levels of immune anti-tumour response in ICR4 tumours, as well as a prolonged survival in comparison to ICR1-3 tumours. Another study have assessed the clinico-biological value of ICR in breast cancer, via the classification of around 8700 breast tumours and assessment of metastasis-free survival and pathological complete response to neoadjuvant chemotherapy.
It has been proven that ICR signature is associated with metastasis-free survival and pathological response to chemotherapy. The increased enrichment of immune signature reflects the expression of cells including T cells, cytotoxic T cells, Th-1 cells, CD8+ T cells, Tγδ cells, and APCs; which defines tumours as immune-active and immune-silent. [7] Although being associated with poor-prognosis, the infiltration of immune cells in ICR4 tumours have resulted in a longer metastasis-free survival and better response to chemotherapy, proving the importance of immune reaction in breast cancer. It was also shown that ICR classification is dependent upon intrinsic molecular subtype of breast tumours, being highly present in triple-negative and HER2+ tumours.
Colon Cancer
A cohort of fresh-frozen samples from 348 patients affected by primary colon cancer (AC-ICAM) was used for genomic examination. this examination revealed that a TH1 cell/cytotoxic immune activation, as captured by the ICR, immunoediting, concurrent expansion of TCR clonotypes and specific intratumoral microbiome composition, were associated with a favorable clinical outcome. The results also revealed that the ICR was associated with overall survival independently of Consensus Molecular Subtypes (CMS) and microsatellite instability (MSI).
In addition, they identified a microbiome signature with strong prognostic value (MBR risk score). The researchers then combined the ICR with the MBR risk score to get a new multi-omics biomarker (mICRoScore) that was able to predict exceptionally long survival in patients with colon cancer.
Pancancer
A pre-existing intratumoral anti-tumor T helper (Th-1) immune response has been linked to favorable outcomes with immunotherapy, but not all immunologically active cancers respond to treatment. In a pan-cancer analysis using The Cancer Genome Atlas (TCGA) including 31 cancer types from 9282 patients, high expression of the ICR signature was associated with significant prolonged survival in breast invasive carcinoma, skin cutaneous melanoma, sarcoma, and uterine corpus endometrial carcinoma, while this "hot" immune phenotype was associated with reduced overall survival in uveal melanoma, low grade glioma, pancreatic adenocarcinoma and kidney renal clear cell carcinoma. In a systemic analysis, cancer-specific pathways were found to modulate the prognostic value of ICR. In tumors with a high proliferation score, ICR was linked to better survival, while in tumors with low proliferation no association with survival was observed. In tumors dominated by cancer signaling, for example by increased TGF beta signaling, the "hot" immune phenotype did not have any survival benefit, suggesting that the immune response is heavily suppressed without protective effect.
The clinical relevance of this finding was demonstrated in the Van Allen dataset with tumor samples of melanoma patients treated with checkpoint inhibitor anti-CTLA4. Overall, a significantly increased expression of ICR was observed in responders compared to non-responders. However, an association of high ICR scores pretreatment with survival was only observed for samples with high proliferation scores. Conversely, ICR was only associated with survival in samples with low TGF beta expression.
Soft tissue sarcoma
In soft tissue sarcoma, a cohort of 1455 non-metastatic samples had the ICR retrospectively applied to them to discover links between ICR classes and clinicopathological and biological variables. Because of this, the cohort was thus divided into 4 groups labelled as ICR1, ICR2, ICR3 and ICR4 with each consisting of 34, 27, 24, and 15% of the tumors. The aforementioned groups were created while taking into account the age age, pathology depth, and enrichment value ICR1 through 4 of quantitative/qualitative scores of immune responses. When ICR1 is compared to ICR2-4 classes, there was an increase of 59% of metastatic relapse. Multivariate analysis also showed that the ICR classification remained associated with MFS as well as pathological type and CINSARC classification, suggesting that there is an independent prognostic value. The presence of an ICR signature is linked to postoperative MFS in early-stage STS, regardless of other prognostic factors such as CINSARC. A prognostic clinicogenomic model was created which combines ICR, CINSARC, and pathological type to provide a reliable prediction of outcomes. Additionally, the study proposes that each prognostic group has varying levels of susceptibility to different systemic therapies.
Pediatric Cancers
A large a systematic analysis of public RNAseq data (TARGET) for five pediatric tumor types: osteosarcoma (OS), neuroblastoma (NBL), clear cell sarcoma of the kidney (CCSK), Wilms tumor (WLM) and rhabdoid tumor of the kidney (RT) showed a very important role of ICR in pediatric tumors. It was discovered that a lower ICR score was associated with lower survival in WLM while higher ICR score was associated with a better survival in OS and high risk NBL without MYCN amplification. Immune traits were then used to cluster the samples into 6 different immune subtypes (S1-S6) with each having different and distinct survival outcomes. For example, the S2 cluster illustrated the highest overall survival, distinguished by low enrichment of the wound healing signature, high Th1, and low Th2 infiltration. However, the opposite was highlighted in S4. Upregulation of the WNT/Beta-catenin pathway was associated with unfavorable outcomes and decreased T-cell infiltration in OS.
Other diseases
Molecular pathways including IFN-stimulated genes activation; the recruitment of NK cells and T cells, by the secretion of CCL5 and CXCL9-10; and the induction of immune effector mechanisms are found overlapping in conditions like autoimmunity, as a results of host-against-self reaction, where immune cells initiate tissue-specific destruction. Similarly, allografting results in a strong immune response, which clinically necessitates a continued immunosuppression to maintain graft survival. They are found to express conformational epitopes, such as MHC molecules, as nonself antigens, which activates both B and T cells.
Alternatives and Variations
T cell–inflamed GEP or Tumor Inflammation Signature (TIS)
An 18-gene Gene Expression Profile that predicted response to pembrolizumab across multiple solid tumors. Can be used with a platform such as the NanoString nCounter platform and define tumor type–independent dimensions of the tumor microenvironment relevant to predicting clinical outcome for agents targeting the PD-1/PD-L1 signaling pathway.
Gene Signature : CCL5, CD27, CD274 (PD-L1), CD276 (B7-H3), CD8A, CMKLR1, CXCL9, CXCR6, HLA-DQA1, HLA-DRB1, HLA-E, IDO1, LAG3, NKG7, PDCD1LG2 (PDL2), PSMB10, STAT1, and TIGIT.
Cytolytic Activity Score (CYT)
A simple 2 gene mean expression score of GZMA and PRF1 expression. High CYT within colorectal cancer is associated with improved survival, likely due to increased immunity and cytolytic activity of T cells and M1 macrophages. The 5-year recurrence-free survival of liver cancer patients with low CYT scores was significantly shorter than that of patients with high CYT scores.
3-lncRNA Signature
researchers found 20 different 20 lnc-RNA prognostic signatures that showed a stronger effect on overall survival than the ICR signature in different solid cancers. They also found a 3 lncRNA signature that displayed prognostic significance in 5 solid cancer types with a stronger association to clinical outcome than ICR and displayed addition prognostic significance in the uterine cohort, endometrial carcinoma, cervical squamous cell carcinomam and endocervical adenocarcinoma as compared to ICR.
References
Immunology | Immunologic constant of rejection | [
"Biology"
] | 2,903 | [
"Immunology"
] |
52,957,819 | https://en.wikipedia.org/wiki/NGC%204861 | NGC 4861, also known as Arp 266, is a galaxy in the constellation Canes Venatici. It was discovered by William Herschel on May 1, 1785.
Morphological classification of NGC 4861 has proved relatively difficult. Its mass, size, and rotational velocity are consistent with it being a spiral galaxy. However, due to its highly irregular shape, it may also be classified as a dwarf irregular galaxy. In fact, since dwarf galaxies are less massive and have lower gravitational potentials, gases and other material for star formation can move within them much faster, causing the galaxy to become a specific type of starburst galaxy, called a blue compact dwarf galaxy. It has also been described as a "comet-like" galaxy due to its resemblance to a comet.
Two ultraluminous X-ray sources (ULXs) have been found within NGC 4861. The first, NGC 4861 X1, is associated with a dense H II region. The second, NGC 4861 X2, seems to be within a small star cluster near the "comet head" of NGC 4861. Assuming it is a star cluster, it has a mass of and an age of 5 million years. Compared to other star clusters with which ULXs are associated, its mass is quite low.
See also
Dwarf irregular galaxy
References
External links
Magellanic spiral galaxies
Barred spiral galaxies
4861
266
08098
44536
Canes Venatici | NGC 4861 | [
"Astronomy"
] | 303 | [
"Canes Venatici",
"Constellations"
] |
52,958,627 | https://en.wikipedia.org/wiki/Cochleatina | Cochleatina is an organic-walled microfossil ('Small Carbonaceous Fossil') known from the late Ediacaran period and early Cambrian Fortunian Stage. Cochleatina comprises a complex spiral ribbon structure, with a serrated outer margin. These spirals are frequently found embedded in an organic sheet. Cochleatina is a rare example of a fossil taxon known to span the Ediacaran–Cambrian boundary.
Affinity
Cochleatina's biological affinity is unknown. It has been variously regarded as the fossil remains of an animal, an algae, or a protist.
References
Incertae sedis
Ediacaran life | Cochleatina | [
"Biology"
] | 135 | [
"Incertae sedis",
"Taxonomy (biology)"
] |
52,959,107 | https://en.wikipedia.org/wiki/Kinematic%20diffraction | Kinematic diffraction is an approximation for diffraction of waves. It assumes that the waves are only scattered once, neglecting multiple scattering. For linear wave equations, it involves summing the contribution of the partial waves emanating from different scatterers, where only the incident field drives the scattering. As a consequence, the far-field amplitude essentially corresponds to the Fourier transform of the scattering length density, which would be the charge density for x-rays and the electrostatic potential for electrons. It is typically understood as the Born approximation applied to a number of scatterers, and as such is often used for X-ray crystallography. The corresponding full theory is called the dynamical theory of diffraction. For x-rays and in electron diffraction different approaches are used to calculating the dynamical diffraction for transmission with high-energy electrons as well as for low energy electron diffraction or reflection high-energy electron diffraction
References
Diffraction | Kinematic diffraction | [
"Physics",
"Chemistry",
"Materials_science"
] | 203 | [
"Materials science stubs",
"Spectrum (physical sciences)",
"Diffraction",
"Crystallography",
"Condensed matter physics",
"Condensed matter stubs",
"Spectroscopy"
] |
52,959,577 | https://en.wikipedia.org/wiki/Vertical%20and%20horizontal%20evacuation | Vertical and horizontal evacuation are strategies for providing safety to humans in case of tsunami, hurricane or other natural disaster.
Vertical evacuation
In areas where horizontal evacuation to higher ground is impossible, vertical evacuation to higher areas of a structure may be a way to shelter individuals from the surge of water, several meters high, that can follow an earthquake in coastal areas.
In the United States
The U.S. Federal Emergency Management Agency published design guidelines for vertical evacuation structures in 2008. According to the American Society of Mechanical Engineers, serious discussions about vertical evacuation began in the United States following the 2011 Tōhoku earthquake and tsunami. The American Society of Civil Engineers adopted an updated edition of its building standards in September 2016, including tsunami hazards for the first time.
The first vertical evacuation site in the United States was Ocosta Elementary School, constructed in 2015–2016 on the Pacific Ocean coast in Westport, Washington, where a Cascadia subduction zone magnitude 9+ earthquake is expected to cause great tsunamis.
Horizontal evacuation
An alternative to vertical evacuation is horizontal evacuation, for instance a hurricane evacuation route. Critics of vertical evacuation planning have charged it with justifying even greater human density in areas prone to disaster, and prefer low density growth with horizontal evacuation planning.
See also
Emergency shelter
References
Bibliography
Further reading
Emergency management
Earthquake and seismic risk mitigation | Vertical and horizontal evacuation | [
"Engineering"
] | 267 | [
"Structural engineering",
"Earthquake and seismic risk mitigation"
] |
52,960,513 | https://en.wikipedia.org/wiki/Zeta%20Fornacis | ζ Fornacis (often Latinised as Zeta Fornacis) is the Bayer designation for a star in the southern constellation of Fornax. It is faintly visible to the naked eye with an apparent visual magnitude of 5.67. Based upon a measured annual parallax shift of , it is located at a distance of about 109 light-years from the Sun. The star is drifting further away with a radial velocity of +29 km/s. Positioned about 1.3° to the southeast of Zeta Fornacis is the galaxy NGC 1232.
This is an F-type main-sequence star with a stellar classification of F4 V. With an estimated age of 1.5 billion years, it has 1.8 times the mass of the Sun and 1.6 times the Sun's radius. The star is radiating 4.77 times the luminosity of the Sun from its photosphere at an effective temperature of . It is spinning with a projected rotational velocity of 84.9 km/s, and has a near-solar metallicity—what astronomers term the abundance of elements other than hydrogen and helium. This star is a probable member of the Hyades Stream—a group of stars that share a common motion through space with the Hyades cluster.
Zeta Fornacis has a common proper motion companion, NLTT 9563, a magnitude 13.50 star with a classification of M 2.5. As of 2004, this companion was positioned at an angular separation of 176.1 arcseconds along a position angle of 288.1°.
References
F-type main-sequence stars
Double stars
Hyades Stream
Fornax
Fornacis, Zeta
CD-25 1191
018692
13942
901 | Zeta Fornacis | [
"Astronomy"
] | 359 | [
"Fornax",
"Constellations"
] |
52,961,252 | https://en.wikipedia.org/wiki/Transition%20metal%20boryl%20complex | In chemistry, a transition metal boryl complex is a molecular species with a formally anionic boron center coordinated to a transition metal. They have the formula LnM-BR2 or LnM-(BR2LB) (L = ligand, R = H, organic substituent, LB = Lewis base). One example is (C5Me5)Mn(CO)2(BH2PMe3) (Me = methyl). Such compounds, especially those derived from catecholborane and the related pinacolborane, are intermediates in transition metal-catalyzed borylation reactions.
Synthesis
Oxidative addition is the main route to metal boryl complexes. Both B-H and B-B bonds add to low-valent metal complexes. For example, catecholborane oxidatively adds to Pt(0) to give the boryl hydride.
C6H4O2BH + Pt(PR3)2 → C6H4O2B Pt(PR3)2H
Addition of diboron tetrafluoride to Vaska's complex gives the triboryl iridium(III) derivative:
2B2F4 + IrCl(CO)(PPh3)2 → Ir(BF2)3(CO)(PPh3)2 + ClBF2
References
Boron
Coordination chemistry | Transition metal boryl complex | [
"Chemistry"
] | 293 | [
"Coordination chemistry"
] |
52,961,576 | https://en.wikipedia.org/wiki/Blastocrithidia%20nuclear%20code | The Blastocrithidia nuclear code (translation table 31) is a genetic code used by the nuclear genome of the trypanosomatid genus Blastocrithidia. This code, along with translation tables 27 and 28, is remarkable in that every one of the 64 possible codons can be a sense codon.
The code (31)
AAs = FFLLSSSSYYEECCWWLLLLPPPPHHQQRRRRIIIMTTTTNNKKSSRRVVVVAAAADDEEGGGG
Starts = ----------**-----------------------M----------------------------
Base1 = TTTTTTTTTTTTTTTTCCCCCCCCCCCCCCCCAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGG
Base2 = TTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGG
Base3 = TCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAG
Bases: adenine (A), cytosine (C), guanine (G) and thymine (T) or uracil (U).
Amino acids: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamic acid (Glu, E), Glutamine (Gln, Q), Glycine (Gly, G), Histidine (His, H), Isoleucine (Ile, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S), Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), and Valine (Val, V).
Differences from the standard code
See also
List of all genetic codes: translation tables 1 to 16, and 21 to 33.
The genetic codes database.
References
Molecular genetics
Gene expression
Protein biosynthesis | Blastocrithidia nuclear code | [
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52,962,536 | https://en.wikipedia.org/wiki/Human%20evolutionary%20developmental%20biology | Human evolutionary developmental biology or informally human evo-devo is the human-specific subset of evolutionary developmental biology. Evolutionary developmental biology is the study of the evolution of developmental processes across different organisms. It is utilized within multiple disciplines, primarily evolutionary biology and anthropology. Groundwork for the theory that "evolutionary modifications in primate development might have led to … modern humans" was laid by Geoffroy Saint-Hilaire, Ernst Haeckel, Louis Bolk, and Adolph Schultz. Evolutionary developmental biology is primarily concerned with the ways in which evolution affects development, and seeks to unravel the causes of evolutionary innovations.
The approach is relatively new, but has roots in Schultz's The physical distinctions of man, from the 1940s. Shultz urged broad comparative studies to identify uniquely human traits.
History
Brian Hall traces the roots of evolutionary developmental biology in his 2012 paper on its past present and future. He begins with Darwinian evolution and Mendel's genetics, noting the tendency of the followers of both men in the early 20th century to follow separate paths and to set aside and ignore apparently inexplicable problems. Greater understanding of genotypic and phenotypic structures from the 1940s enabled the unification of evolution and genetics in the modern synthesis. Molecular biology then enabled researchers to explore the mechanisms and evolution of embryonic development in molecular detail, including in humans.
Human and primate development
Many of the human evolutionary developmental biology studies have been modeled after primate studies and consider the two together in a comparative model. Brain ontogeny and human life history evolution were looked at by Leigh, in a 2006 paper. He compares brain growth patterns for Homo erectus and Homo sapiens to get at the evolution of brain size and weight. Leigh found three different patterns, all of which pointed to the growth rate of H. erectus either matching or exceeding H. erectus. He makes the case that this finding had wide application and relevance to the overall study of human evolution. It is pertinent specifically to the connections between energy expenditure and brain development. These finding are of specific utility in studies on maternal energy expenditure. Comparative study of nonhuman primates, fossils and modern humans to study patterns of brain growth to correlate human life history and brain growth.
Jeremy De Silva and Julie Lesnik examined chimpanzee neonatal brain size to identify implications for brain growth in Homo erectus. This changed the understanding of differences and similarities of post-natal brain growth in humans and chimpanzees. The study found that there was a distinction necessary between growth time and growth rate. The times of growth were strikingly similar, but the rates were not. The paper further advocates the use of fossils to assess brain size in general and in relation to cranial capacity.
Utilization of endocranial volume as a measure for brain size has been a popular methodology with the fossil record since Darwin in the mid 1800s. This measure has been used to access the metabolic requirements for brain growth and the subsequent trade-offs.
Neoteny
Some of the work on human evolutionary developmental biology has centered around the neotenous features that present in humans, but are not shared across the primate spectrum. Steven J. Gould discussed the presentation of neoteny with "terminal additions" in humans. Neoteny is defined as the delayed or slowed development in humans when compared with their non-human primate counterparts. The "terminal additions" were extensions or reductions in the rate and scope of stages of development and growth. Gould hypothesized that this process and production of neoteny in humans might be the key feature that ultimately lead to the emotional and communicative nature of humans. He credits this factor as an integral facet of human evolution. However, there have also been cautions against the application of this aspect to group ranking during it inappropriate as a measure of evolutionary achievement.
Fossil record
Early comparative and human studies examined the fossil record to measure features like cranial sizes and capacities so as to infer brain size, growth rate, total growth and potential implications for energy expenditure. Helpful as this is, the static nature of individual fossils presents its own challenge. The phylogenic fossil line is itself a hypothesis, so anything based upon it is equally hypothetical.
Using the fossil record of Neanderthals, modern humans, and chimpanzees, Gunz et al. examined that patterns of endocranial development. They found that there are common features shared between the three, and that modern humans diverge from these common patterns in the first year of life. They concluded that even though much of the developmental results are similar insofar as brain size, the trajectories by which they arrived are not shared. Most of the differences between the two arise post-natally, in the first year, with cognitive development.
There have been a number of studies that not only take incomplete fossil records into consideration, but have attempted to specifically identify the barriers presented by this condition. For example, Kieran McNulty covers the potential utilities and constraints of using incomplete fossil taxa to examine longitudinal development in Australopithecus africanis.
Many studies on development have been human-specific. In his 2011 paper, Bernard Crespi focused on adaptation and genomic conflict in childhood diseases. He considers the evolution of childhood diseases and their risk levels, and finds that both risk and disease have evolved.
Hotchberg and Belsky incorporate a life-history perspective, looking at adolescence. Substantial variation in phenotypic paths and presentations suggest significant environmental influence. They focus on plasticity between stages of development and the factors that shape it. Rate of maturation, fecundity, and fertility were all impacted by environmental circumstances. They argue that early maturation can be positive, reflecting opportunistic actions within specific conditions.
Genetic and epigenetic basis
Technological advances that have allowed better and better access to the growth of the human form in utero have proven particularly formative in studies involving focus on genetic and epigenetic development. Bakker et al. look at the interconnected nature of developmental processes and attempt to use fetal vertebral abnormalities as an indicator for other malformations. They found that the origin of the cells was not nearly as highly correlated as the observed developmental signals. In utero development and malformations were correlated in severity.
Freiston and Galis look at the development of ribs, digits, and mammalian asymmetry. They argue that this construction is relevant for the study of disease, the consistency in evolution of body plans, and understanding of developmental constraints. Sexual dimorphism in prenatal digit ratio was found as early as 14 weeks and was maintained whether or not the fleshy finger part was included.
Language and cognitive studies
Languages and cognitive function have also been subjects of evolutionary studies. Insofar as language and evolutionary developmental biology, there is tension from the gate. Much of this contention has centered around whether to view and study language as an adaptation in and of itself, or as a by-product of other adaptations. Jackendoff and Pinker have argued for language as an adaptation owing to the interdependent social nature of humans. To support these claims, he points to things like the bi-directionality in language usage and comprehension. This is a counter to the claims by theorists like Noam Chomsky, who argued against language as a human specific adaptation.
Adaptation and adaptive theory has been argued even separate from its utility in the study of language. Gould and Lewontin engage with what they saw as flaws in adaptive theory using the analogy of the spandrels of San Marco. Among the issues identified is the lack of distinction between what trait developed and how it is used, and the underlying reasons or forces that created the novel trait initially. This is particularly difficult to access in intangible language and cognition.
This debate has continued over decades and most often presents in the form of a response and published dialogue between theorists. This continued debate has prompted efforts to marry the two perspectives in a useful way. Fitch argues that these two approaches can be rectified with the study of "neutral computation and mammalian brain development". It may be more useful to consider specific components of neural computation and development, what has been selected for, and to what end.
Ploeger and Galis tackled modular evolvability and developmental constraints in human and other primate evolutionary trajectories. They argue that these should be treated with an interdisciplinary approach across the cognitive sciences. They frame this in the context of:
Modularity — the ability of a system to organize individuals for the benefit of the whole
Evolvability — ability of organism or organisms to adapt through evolution
Developmental constraints — those things that act as barriers to evolutionary adaptations.
See also
Regulation of gene expression
References
Sources
Evolutionary biology
Human population genetics | Human evolutionary developmental biology | [
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52,965,026 | https://en.wikipedia.org/wiki/Hidden%20Figures%20%28book%29 | Hidden Figures: The American Dream and the Untold Story of the Black Women Who Helped Win the Space Race is a 2016 nonfiction book written by Margot Lee Shetterly.
Synopsis
Shetterly started working on the book in 2010. The book takes place from the 1930s through the 1960s, depicting the particular barriers for Black women in science during this time, thereby providing a lesser-known history of NASA. The biographical text follows the lives of Katherine Johnson, Dorothy Vaughan, and Mary Jackson, three mathematicians who worked as computers (then a job description) at NACA and NASA, during the space race. They overcame discrimination there, as women and as African Americans. Also featured is Christine Darden, who was the first African-American woman to be promoted into the Senior Executive Service for her work in researching supersonic flight and sonic booms.
Hidden Figures explores the biographies of three African-American women who worked as computers to solve problems for engineers and others at NASA. For the first years of their careers, the workplace was segregated and women were kept in the background as human computers. Author Margot Lee Shetterly's father was a research scientist at NASA who worked with many of the book's main characters.
Shetterly explains how these women overcame discrimination and racial segregation to become vital parts of mathematics, scientific, and engineering history. One of them, Katherine Johnson, calculated rocket trajectories for the Mercury and Apollo missions. Johnson successfully "took matters into her own hands" by being assertive with her supervisor. When her mathematical abilities were recognized, Johnson was allowed into what had previously been all-male meetings at NASA.
Reception
The book reached number one on The New York Times Non-Fiction Best Sellers list and got the Anisfield-Wolf Book Award for Nonfiction in 2017. The book was adapted as a film by the same name, released in 2016, that was nominated for three Oscars. It received numerous other awards.
Film
The book was adapted as a film of the same name, written by Theodore Melfi and Allison Schroeder, and directed by Melfi. It was released on December 25, 2016 to positive reviews from critics, and received a nomination for Best Picture at the 89th Academy Awards. It received numerous other nominations and awards. Taraji P. Henson starred as mathematician Katherine Johnson, Octavia Spencer played Dorothy Vaughan, an African-American mathematician who worked for NASA in 1949, and Janelle Monáe played Mary Jackson, the first female African-American engineer to work for NASA. The movie made US$231.3 million. The budget of the film was US$25 million.
While the film is based on the book, author Margot Lee Shetterly agrees that there are differences between the two, and she finds that to be understandable.
For better or for worse, there is history, there is the book and then there's the movie. Timelines had to be conflated and [there were] composite characters, and for most people [who have seen the movie] have already taken that as the literal fact. You might get the indication in the movie that these were the only people doing those jobs, when in reality we know they worked in teams, and those teams had other teams. There were sections, branches, divisions, and they all went up to a director. There were so many people required to make this happen. It would be great for people to understand that there were so many more people. Even though Katherine Johnson, in this role, was a hero, there were so many others that were required to do other kinds of tests and checks to make [Glenn's] mission come to fruition. But I understand you can't make a movie with 300 characters. It is simply not possible.
Other adaptations
In 2016 a Young Reader's Edition was released for readers ages 8–12.
A Hidden Figures picture book was released in January 2018. The book was co-written by Margot Lee Shetterly for children from four to eight years of age.
See also
West Area Computers
Kathaleen Land
References
External links
Presentation by Shetterly on Hidden Figures at the Hampton History Museum, September 8, 2016, C-SPAN
Discussion with Shetterly on Hidden Figures at the National Book Festival, September 2, 2017, C-SPAN
2016 non-fiction books
American non-fiction books
Books about African-American history
Books about the Cold War
Books about women
Non-fiction books adapted into films
NASA mass media
Women in mathematics
Biographies and autobiographies of mathematicians
Literature by African-American women
William Morrow and Company books | Hidden Figures (book) | [
"Technology"
] | 928 | [
"Women in science and technology",
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52,966,974 | https://en.wikipedia.org/wiki/In%20situ%20bioremediation | Bioremediation is the process of decontaminating polluted sites through the usage of either endogenous or external microorganism. In situ is a term utilized within a variety of fields meaning "on site" and refers to the location of an event. Within the context of bioremediation, in situ indicates that the location of the bioremediation has occurred at the site of contamination without the translocation of the polluted materials. Bioremediation is used to neutralize pollutants including Hydrocarbons, chlorinated compounds, nitrates, toxic metals and other pollutants through a variety of chemical mechanisms. Microorganism used in the process of bioremediation can either be implanted or cultivated within the site through the application of fertilizers and other nutrients. Common polluted sites targeted by bioremediation are groundwater/aquifers and polluted soils. Aquatic ecosystems affected by oil spills have also shown improvement through the application of bioremediation. The most notable cases being the Deepwater Horizon oil spill in 2010 and the Exxon Valdez oil spill in 1989. Two variations of bioremediation exist defined by the location where the process occurs. Ex situ bioremediation occurs at a location separate from the contaminated site and involves the translocation of the contaminated material. In situ occurs within the site of contamination In situ bioremediation can further be categorized by the metabolism occurring, aerobic and anaerobic, and by the level of human involvement.
History
The Sun Oil pipeline spill in Ambler, Pennsylvania spurred the first commercial usage of in situ bioremediation in 1972 to remove hydrocarbons from contaminated sites. A patent was filed in 1974 by Richard Raymond, Reclamation of Hydrocarbon Contaminated Ground Waters, which provided the basis for the commercialization of in situ bioremediation.
Classifications of In situ Bioremediation
Accelerated
Accelerated in situ bioremediation is defined when a specified microorganism is targeted for growth through the application of either nutrients or an electron donor to the contaminated site. Within aerobic metabolism the nutrient added to the soil can be solely Oxygen. Anaerobic in situ bioremediation often requires a variety of electron donors or acceptors such as benzoate and lactate. Besides nutrients, microorganisms can also be introduced directly to the site within accelerated in situ bioremediation. The addition of extraneous microorganisms to a site is termed bioaugmentation and is used when a particular microorganism is effective at degrading the pollutant at the site and is not found either naturally or at a high enough population to be effective. Accelerated in situ bioremediation is utilized when the desired population of microorganisms within a site is not naturally present at a sufficient level to effectively degrade the pollutants. It also is used when the required nutrients within the site are either not at a concentration sufficient to support growth or are unavailable.
Raymond Process
The Raymond Process is a type of accelerated in situ bioremediation that was developed by Richard Raymond and involves the introduction of nutrients and electron acceptors to a contaminated site. This process is primarily used to treat polluted groundwater. In the Raymond process a loop system is created. Contaminated Groundwater from downstream of the groundwater flow is pumped to the surface and infused with nutrients and an electron donor, often oxygen. This treated water is then pumped back down below the water table upstream of where it was originally taken. This process introduces nutrients and electron donors into the site allowing for the growth of a determined microbial population.
Oxygen Injection
In contaminated sites where the desired microbial metabolism is aerobic the introduction of oxygen to the site can be used to increase the population of targeted microorganisms. The injection of Oxygen can occur through a variety of processes. Oxygen can be injected into the subsurface through injection wells. It can also be introduced through an injection gallery. The presence of oxygen within a site is often the limiting factor when determining the time frame and efficacy of a proposed in situ bioremediation process.
Ozone Injection
Ozone injected into the subsurface can also be a means of introducing oxygen into a contaminated site. Despite being a strong oxidizing agent and potentially having a toxic effect on subsurface microbial populations, ozone can be an efficient means of spreading oxygen throughout a site due to its high solubility. Within twenty minutes after being injected into the subsurface, fifty percent of the ozone will have decomposed to Oxygen. Ozone is commonly introduced to the soil in either a dissolved or gaseous state.
Accelerated Anaerobic In situ Bioremediation
Within accelerated anaerobic in situ bioremediation electron donors and acceptors are introduced into a contaminated site in order to increase the population of anaerobic microorganisms.
Monitored Natural Attenuation (MNA)
Monitored Natural Attenuation is in situ bioremediation that occurs with little to no human intervention. This process relies on the natural microbial populations sustained within the contaminated sites to over time reduce the contaminants to a desired level. During monitored natural attenuation the site is monitored in order to track the progress of the bioremediation. Monitored natural attenuation is used in sites where the source of contamination is no longer present, often after other more active types of in situ bioremediation have been conducted.
Uses of In situ bioremediation
Hydrocarbon Degradation
Naturally occurring within the soil are microbial populations that utilize hydrocarbons as a source of energy and carbon. Upwards to twenty percent of microbial soil populations have the ability to metabolize hydrocarbons. These populations can through either accelerated or natural monitored attenuation be utilized to neutralize within the soil hydrocarbon pollutants. The metabolic mode of hydrocarbon remediation is primarily aerobic. The end products of the remediation for hydrocarbons are Carbon Dioxide and water. Hydrocarbons vary in ease of degradation based on their structure. Long chain aliphatic carbons are the most effectively degraded. Short chained, branched, and quaternary aliphatic hydrocarbons are less effectively degraded. Alkene degradation is dependent on the saturation of the chain with saturated alkenes being more readily degraded. Large numbers of microbes with the ability to metabolize aromatic hydrocarbons are present within the soil. Aromatic hydrocarbons are also susceptible to being degraded through anaerobic metabolism. Hydrocarbon metabolism is an important facet of in situ bioremediation due to the severity of petroleum spills around the world. Polynuclear aromatic carbons susceptibility to degradation is related to the number of aromatic rings within the compound. Compounds with two or three rings are degraded at an effective rate, but compounds possessing four or more rings can be more resilient to bioremediation efforts. Degradation of polynuclear aromatic carbons with less than four rings is accomplished by various aerobic microbes present in the soil. Meanwhile, for larger-molecular-sized compounds, the only metabolic mode that has shown to be effective is cometabolism. The fungus genus Phanerochaete under anaerobic conditions has species with the ability to metabolize some polynuclear aromatic carbons utilizing a peroxidase enzyme.
Chlorinated Compounds
Chlorinated Aliphatic Compounds
A variety of metabolic modes exist capable of degrading chlorinated aliphatic compounds. Anaerobic reduction, oxidation of the compound, and cometabolism under aerobic conditions are the three main metabolic modes utilized by microorganisms to degrade chlorinated aliphatic compounds. Organisms that can readily metabolize chlorinated aliphatic compounds are not common in the environment. One and two carbons that have little chlorination are the compounds most effectively metabolized by soil microbial populations. The degradation of chlorinated aliphatic compounds is most often performed through cometabolism.
Chlorinated Aromatic Hydrocarbons
Chlorinated aromatic hydrocarbons are resistant to bioremediation and many microorganisms lack the ability to degrade the compounds. Chlorinated aromatic hydrocarbons are most often degraded through a process of reductive dechlorination under anaerobic conditions. Polychlorinated biphenyls (PCBs) are primarily degraded through cometabolism. There are also some fungi that can degrade these compounds as well. Studies show an increase in PCB degradation when biphenyl is added to the site due to cometabolic effects that the enzymes used to degrade biphenyl have on PCBs.
Benefits
Due to in situ bioremediation taking place at the site of contamination there is a lessened risk of cross contamination as opposed to ex situ bioremediation where the polluted material is transported to other sites. In situ bioremediation can also have lower costs and a higher rate of decontamination than ex situ bioremediation.
References
Biodegradable materials
Biodegradable waste management
Biodegradation
Bioremediation
Biotechnology
History of biotechnology
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52,968,860 | https://en.wikipedia.org/wiki/Biodiversity%20loss | Biodiversity loss happens when plant or animal species disappear completely from Earth (extinction) or when there is a decrease or disappearance of species in a specific area. Biodiversity loss means that there is a reduction in biological diversity in a given area. The decrease can be temporary or permanent. It is temporary if the damage that led to the loss is reversible in time, for example through ecological restoration. If this is not possible, then the decrease is permanent. The cause of most of the biodiversity loss is, generally speaking, human activities that push the planetary boundaries too far. These activities include habitat destruction (for example deforestation) and land use intensification (for example monoculture farming). Further problem areas are air and water pollution (including nutrient pollution), over-exploitation, invasive species and climate change.
Many scientists, along with the Global Assessment Report on Biodiversity and Ecosystem Services, say that the main reason for biodiversity loss is a growing human population because this leads to human overpopulation and excessive consumption. Others disagree, saying that loss of habitat is caused mainly by "the growth of commodities for export" and that population has very little to do with overall consumption. More important are wealth disparities between and within countries.
Climate change is another threat to global biodiversity. For example, coral reefs—which are biodiversity hotspots—will be lost by the year 2100 if global warming continues at the current rate. Still, it is the general habitat destruction (often for expansion of agriculture), not climate change, that is currently the bigger driver of biodiversity loss. Invasive species and other disturbances have become more common in forests in the last several decades. These tend to be directly or indirectly connected to climate change and can cause a deterioration of forest ecosystems.
Groups that care about the environment have been working for many years to stop the decrease in biodiversity. Nowadays, many global policies include activities to stop biodiversity loss. For example, the UN Convention on Biological Diversity aims to prevent biodiversity loss and to conserve wilderness areas. However, a 2020 United Nations Environment Programme report found that most of these efforts had failed to meet their goals. For example, of the 20 biodiversity goals laid out by the Aichi Biodiversity Targets in 2010, only six were "partially achieved" by 2020.
This ongoing global extinction is also called the holocene extinction or sixth mass extinction.
Global estimates across all species
The current rate of global biodiversity loss is estimated to be 100 to 1000 times higher than the (naturally occurring) background extinction rate, faster than at any other time in human history, and is expected to grow in the upcoming years. The fast-growing extinction trends of various animal groups like mammals, birds, reptiles, amphibians, and fish have led scientists to declare a current biodiversity crisis in both land and ocean ecosystems.
In 2006, many more species were formally classified as rare or endangered or threatened; moreover, scientists have estimated that millions more species are at risk that have not been formally recognized.
Deforestation also plays a large role in biodiversity loss. More than half of the worlds biodiversity is hosted in tropical rainforest. Regions that are subjected to exponential loss of biodiversity are referred to as biodiversity hotspots. Since 1988 the hotspots increased from 10 to 34. Of the total 34 hotspots currently present, 16 of them are in tropical regions (as of 2006). Researchers have noted in 2006 that only 2.3% of the world is covered with biodiversity loss hotspots, and even though only a small percentage of the world is covered in hotspots, it host a large fraction (50%) of vascular plant species.
In 2021, about 28 percent of the 134,400 species assessed using the IUCN Red List criteria are now listed as threatened with extinction—a total of 37,400 species compared to 16,119 threatened species in 2006.
A 2022 study that surveyed more than 3,000 experts found that "global biodiversity loss and its impacts may be greater than previously thought", and estimated that roughly 30% of species "have been globally threatened or driven extinct since the year 1500."
Research published in 2023 found that, out of 70,000 species, about 48% are facing decreasing populations due to human activities, while only 3% are seeing an increase in populations.
Methods to quantify loss
Biologists define biodiversity as the "totality of genes, species and ecosystems of a region". To measure biodiversity loss rates for a particular location, scientists record the species richness and its variation over time in that area. In ecology, local abundance is the relative representation of a species in a particular ecosystem. It is usually measured as the number of individuals found per sample. The ratio of abundance of one species to one or multiple other species living in an ecosystem is called relative species abundance. Both indicators are relevant for computing biodiversity.
There are many different biodiversity indexes. These investigate different scales and time spans. Biodiversity has various scales and subcategories (e.g. phylogenetic diversity, species diversity, genetic diversity, nucleotide diversity).
The question of net loss in confined regions is often a matter of debate.
Observations by type of life
Wildlife in general
An October 2020 analysis by Swiss Re found that one-fifth of all countries are at risk of ecosystem collapse as the result of anthropogenic habitat destruction and increased wildlife loss. If these losses are not reversed, a total ecosystem collapse could ensue.
In 2022, the World Wildlife Fund reported an average population decline of 68% between 1970 and 2016 for 4,400 animal species worldwide, encompassing nearly 21,000 monitored populations.
Terrestrial invertebrates
Insects
Earthworms
Scientists have studied loss of earthworms from several long-term agronomic trials. They found that relative biomass losses of minus 50–100% (with a mean of minus 83 %) match or exceed those reported for other faunal groups. Thus it is clear that earthworms are similarly depleted in the soils of fields used for intensive agriculture. Earthworms play an important role in ecosystem function, helping with biological processing in soil, water, and even greenhouse gas balancing. There are five reasons for the decline of earthworm diversity: "(1) soil degradation and habitat loss, (2) climate change, (3) excessive nutrient and other forms of contamination load, (4) over-exploitation and unsustainable management of soil, and (5) invasive species". Factors like tillage practices and intensive land use decimate the soil and plant roots that earthworms use to create their biomass. This interferes with carbon and nitrogen cycles.
Knowledge of earthworm species diversity is quite limited as not even 50% of them have been described. Sustainable agriculture methods could help prevent earthworm diversity decline, for example reduced tillage. The Secretariat of the Convention on Biological Diversity is trying to take action and promote the restoration and maintenance of the many diverse species of earthworms.
Amphibians
Wild mammals
Birds
Some pesticides, like insecticides, likely play a role in reducing the populations of specific bird species. According to a study funded by BirdLife International, 51 bird species are critically endangered and eight could be classified as extinct or in danger of extinction. Nearly 30% of extinction is due to hunting and trapping for the exotic pet trade. Deforestation, caused by unsustainable logging and agriculture, could be the next extinction driver, because birds lose their habitat and their food.
Plants
Trees
While plants are essential for human survival, they have not received the same attention as the conservation of animals. It is estimated that a third of all land plant species are at risk of extinction and 94% have yet to be evaluated in terms of their conservation status. Plants existing at the lowest trophic level require increased conservation to reduce negative impacts at higher trophic levels.
In 2022, scientists warned that a third of tree species are threatened with extinction. This will significantly alter the world's ecosystems because their carbon, water and nutrient cycles will be affected. Forest areas are degraded due to common factors such as logging, fire, and firewood harvesting. The GTA (global tree assessment) has determined that "17,510 (29.9%) tree species are considered threatened with extinction. In addition, there are 142 tree species recorded as Extinct or Extinct in the Wild."
Possible solutions can be found in some silvicultural methods of forest management that promote tree biodiversity, such as selective logging, thinning or crop tree management, and clear cutting and coppicing. Without solutions, secondary forests recovery in species richness can take 50 years to recover the same amount as the primary forest, or 20 years to recover 80% of species richness.
Flowering plants
Freshwater species
Freshwater ecosystems such as swamps, deltas, and rivers make up 1% of earth's surface. They are important because they are home to approximately one third of vertebrate species. Freshwater species are beginning to decline at twice the rate of species that live on land or in the ocean. This rapid loss has already placed 27% of 29,500 species dependent on fresh water on the IUCN Red List.
Global populations of freshwater fish are collapsing due to water pollution and overfishing. Migratory fish populations have declined by 76% since 1970, and large "megafish" populations have fallen by 94% with 16 species declared extinct in 2020.
Marine species
Marine biodiversity encompasses any living organism that resides in the ocean or in estuaries. By 2018, approximately 240,000 marine species had been documented. But many marine species—estimates range between 178,000 and 10 million oceanic species—remain to be described. It is therefore likely that a number of rare species (not seen for decades in the wild) have already disappeared or are on the brink of extinction, unnoticed.
Human activities have a strong and detrimental influence on marine biodiversity. The main drivers of marine species extinction are habitat loss, pollution, invasive species, and overexploitation. Greater pressure is placed on marine ecosystems near coastal areas because of the human settlements in those areas.
Overexploitation has resulted in the extinction of over 25 marine species. This includes seabirds, marine mammals, algae, and fish. Examples of extinct marine species include Steller's sea cow (Hydrodamalis gigas) and the Caribbean monk seal (Monachus tropicalis). Not all extinctions are because of humans. For example, in the 1930s, the eelgrass limpet (Lottia alveus) became extinct in the Atlantic once the Zostera marina seagrass population declined upon exposure to a disease. The Lottia alveus were greatly impacted because the Zostera marina were their sole habitats.
Causes
The main causes of current biodiversity loss are:
Habitat loss, fragmentation and degradation; for example habitat fragmentation for commercial and agricultural uses (specifically monoculture farming)
Land use intensification (and ensuing land loss/habitat loss); a significant factor in loss of ecological services due to direct effects as well as biodiversity loss
Nutrient pollution and other forms of pollution (air and water pollution)
Overexploitation and unsustainable use (for example unsustainable fishing methods, overfishing, overconsumption and human overpopulation)
Invasive species that effectively compete for a niche, replacing indigenous species
Climate change (e.g. extinction risk from climate change, effects of climate change on plant biodiversity)
Jared Diamond describes an "Evil Quartet" of habitat destruction, overkill, introduced species and secondary extinctions. Edward O. Wilson suggested the acronym HIPPO for the main causes of biodiversity loss: Habitat destruction, Invasive species, Pollution, human over-Population and Over-harvesting.
Habitat destruction
For example, habitat loss is one of the causes in the decline of insect populations (see the section below on insects).
Urban growth and habitat fragmentation
The direct effects of urban growth on habitat loss are well understood: building construction often results in habitat destruction and fragmentation. This leads to selection for species that are adapted to urban environments. Small habitat patches cannot support the level of genetic or taxonomic diversity they formerly could while some more sensitive species may become locally extinct. Species abundance populations are reduced due to the reduced fragmented area of habitat. This causes an increase of species isolation and forces species toward edge habitats and to adapt to foraging elsewhere.
Infrastructure development in Key Biodiversity Areas (KBA) is a major driver of biodiversity loss, with infrastructure present in roughly 80% of KBAs. Infrastructure development leads to conversion and fragmentation of natural habitat, pollution and disturbance. There can also be direct harm to animals through collisions with vehicles and structures. This can have impacts beyond the infrastructure site.
Land use intensification
Humans are changing the uses of land in various ways, and each can lead to habitat destruction and biodiversity loss. The 2019 Global Assessment Report on Biodiversity and Ecosystem Services found that industrial agriculture is the primary driver of biodiversity collapse. The UN's Global Biodiversity Outlook 2014 estimated that 70% of the projected loss of terrestrial biodiversity is caused by agriculture use. According to a 2005 publication, "Cultivated systems [...] cover 24% of Earth's surface". The publication defined cultivated areas as "areas in which at least 30% of the landscape is in croplands, shifting cultivation, confined livestock production, or freshwater aquaculture in any particular year".
More than 17,000 species are at risk of losing habitat by 2050 as agriculture continues to expand to meet future food needs (as of 2020). A global shift toward largely plant-based diets would free up land to allow for the restoration of ecosystems and biodiversity. In the 2010s over 80% of all global farmland was used to rear animals.
As of 2022, 44% of Earth's land area required conservation attention, which may include declaring protected areas and following land-use policies.
Nutrient pollution and other forms of pollution
Air pollution
Air pollution adversely affects biodiversity. Pollutants are emitted into the atmosphere by the burning of fossil fuels and biomass, for example. Industrial and agricultural activity releases the pollutants sulfur dioxide and nitrogen oxides. Once sulfur dioxide and nitrogen oxide are introduced into the atmosphere, they can react with cloud droplets (cloud condensation nuclei), raindrops, or snowflakes, forming sulfuric acid and nitric acid. With the interaction between water droplets and sulfuric and nitric acids, wet deposition occurs and creates acid rain.
A 2009 review studied four air pollutants (sulfur, nitrogen, ozone, and mercury) and several types of ecosystems. Air pollution affects the functioning and biodiversity of terrestrial as well as aquatic ecosystems. For example, "air pollution causes or contributes to acidification of lakes, eutrophication of estuaries and coastal waters, and mercury bioaccumulation in aquatic food webs".
Noise pollution
Noise generated by traffic, ships, vehicles, and aircraft can affect the survivability of wildlife species and can reach undisturbed habitats. Noise pollution is common in marine ecosystems, affecting at least 55 marine species. One study found that as seismic noises and naval sonar increases in marine ecosystems, cetacean diversity decreases (including whales and dolphins). Multiple studies have found that fewer fishes, such as cod, haddock, rockfish, herring, sand seal, and blue whiting, have been spotted in areas with seismic noises, with catch rates declining by 40–80%.
Noise pollution has also altered avian communities and diversity. Noise can reduce reproductive success, minimize nesting areas, increase stress response, and reduce species abundance. Noise pollution can alter the distribution and abundance of prey species, which can then impact predator populations.
Pollution from fossil fuel extraction
Fossil fuel extraction and associated oil and gas pipelines have major impacts on the biodiversity of many biomes due to land conversion, habitat loss and degradation, and pollution. An example is the Western Amazon region. Exploitation of fossil fuels there has had significant impacts on biodiversity. As of 2018, many of the protected areas with rich biodiversity were in areas containing unexploited fossil fuel reserves worth between $3 and $15 trillion. The protected areas may be under threat in future.
Overexploitation
Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term applies to natural resources such as water aquifers, grazing pastures and forests, wild medicinal plants, fish stocks and other wildlife.
Overfishing
A 2019 Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services report found that overfishing is the main driver of mass species extinction in oceans. Overfishing has reduced fish and marine mammal biomass by 60% since the 1800s. It is currently pushing over one-third of sharks and rays toward extinction.
Many commercial fishes have been overharvested: a 2020 FAO report classified as overfished 34% of the fish stocks of the world's marine fisheries. By 2020, global fish populations had declined 38% since 1970.
Many regulatory measures are available for controlling overfishing. These include fishing quotas, bag limits, licensing, closed seasons, size limits, and the creation of marine reserves and other marine protected areas.
Human overpopulation and overconsumption
The world's population numbered nearly 7.6 billion as of mid-2017 and is forecast to peak toward the end of the 21st century at 10–12 billion people. Scholars have argued that population size and growth, along with overconsumption, are significant factors in biodiversity loss and soil degradation. Review articles, including the 2019 IPBES report, have also noted that human population growth and overconsumption are significant drivers of species decline. A 2022 study warned that conservation efforts will continue to fail if the primary drivers of biodiversity loss continue to be ignored, including population size and growth.
Other scientists have criticized the assertion that population growth is a key driver for biodiversity loss. They argue that the main driver is the loss of habitat, caused by "the growth of commodities for export, particularly soybean and oil-palm, primarily for livestock feed or biofuel consumption in higher income economies." Because of the wealth disparities between countries, there is a negative correlation between a country's total population and its per capita footprint. On the other hand, the correlation between a country's GDP and its footprint is strong. The study argues that population as a metric is unhelpful and counterproductive for tackling environmental challenges.
Invasive species
The term invasive is poorly defined and often very subjective. The European Union defines invasive alien species as those outside their natural distribution area that threaten biological diversity. Biotic invasion is considered one of the five top drivers of global biodiversity loss and is increasing because of tourism and globalization. This may be particularly true in poorly regulated fresh water systems, though quarantines and ballast water rules have improved the situation.
Invasive species may drive local native species to extinction via competitive exclusion, niche displacement, or hybridisation with related native species. Therefore, alien invasions may result in extensive changes in the structure, composition and global distribution of the biota at sites of introduction. This leads to the homogenisation of the world's fauna and flora and biodiversity loss.
Climate change
Climate change is another threat to global biodiversity. But habitat destruction, e.g., for the expansion of agriculture, is currently a more significant driver of biodiversity loss.
A 2021 collaborative report by scientists from the IPBES and the IPCC found that biodiversity loss and climate change must be addressed simultaneously, as they are inextricably linked and have similar effects on human well-being. In 2022, Frans Timmermans, Vice-President of the European Commission, said that people are less aware of the threat of biodiversity loss than they are of the threat of climate change.
The interaction between climate change and invasive species is complex and not easy to assess. Climate change is likely to favour some invasive species and harm others, but few authors have identified specific consequences of climate change for invasive species.
Invasive species and other disturbances have become more common in forests in the last several decades. These tend to be directly or indirectly connected to climate change and have negative consequences for forest ecosystems.
Extinction risks
Impacts
On ecosystems
Biodiversity loss has bad effects on the functioning of ecosystems. This in turn affects humans, because affected ecosystems can no longer provide the same quality of ecosystem services, such as crop pollination, cleaning air and water, decomposing waste, and providing forest products as well as areas for recreation and tourism.
Two key statements of a 2012 comprehensive review of the previous 20 years of research include:
"There is now unequivocal evidence that biodiversity loss reduces the efficiency by which ecological communities capture biologically essential resources, produce biomass, decompose and recycle biologically essential nutrients"; and
"Impacts of diversity loss on ecological processes might be sufficiently large to rival the impacts of many other global drivers of environmental change"
Permanent global species loss (extinction) is a more dramatic phenomenon than regional changes in species composition. But even minor changes from a healthy stable state can have a dramatic influence on the food web and the food chain, because reductions in one species can adversely affect the entire chain (coextinction). This can lead to an overall reduction in biodiversity, unless alternative stable states of the ecosystem are possible.
For example, a study on grasslands used manipulated grassland plant diversity and found that ecosystems with higher biodiversity show more resistance of their productivity to climate extremes.
On food and agriculture
In 2019, the UN's Food and Agriculture Organization (FAO) produced its first report on The State of the World's Biodiversity for Food and Agriculture. It warned that "Many key components of biodiversity for food and agriculture at genetic, species and ecosystem levels are in decline."
The report also said, "Many of the drivers that have negative impacts on BFA (biodiversity for food and agriculture), including overexploitation, overharvesting, pollution, overuse of external inputs, and changes in land and water management, are at least partially caused by inappropriate agricultural practices" and "transition to intensive production of a reduced number of species, breeds and varieties, remain major drivers of loss of BFA and ecosystem services."
To reduce biodiversity loss related to agricultural practices, FAO encourages the use of "biodiversity-friendly management practices in crop and livestock production, forestry, fisheries and aquaculture".
On health and medicines
The WHO has analyzed how biodiversity and human health are connected: "Biodiversity and human health, and the respective policies and activities, are interlinked in various ways. First, biodiversity gives rise to health benefits. For example, the variety of species and genotypes provide nutrients and medicines." The ongoing drivers and effects of biodiversity loss has the potential to lead to future zoonotic disease outbreaks like the COVID-19 pandemic.
Medicinal and aromatic plants are widely used in traditional medicine as well as in cosmetic and food industries. The WHO estimated in 2015 that about "60,000 species are used for their medicinal, nutritional and aromatic properties". There is a global trade in plants for medicinal purposes.
Biodiversity contributes to the development of pharmaceuticals. A significant proportion of medicines are derived from natural products, either directly or indirectly. Many of these natural products come from marine ecosystems. However, unregulated and inappropriate over-harvesting (bioprospecting) could potentially lead to overexploitation, ecosystem degradation and loss of biodiversity. Users and traders harvest plants for traditional medicine either by planting them or by collecting them in the wild. In both cases, sustainable medicinal resource management is important.
Proposed solutions
Scientists are investigating what can be done to address biodiversity loss and climate change together. For both of these crises, there is a need to "conserve enough nature and in the right places". A 2020 study found that "beyond the 15% land area currently protected, 35% of land area is needed to conserve additional sites of particular importance for biodiversity and stabilize the climate."
Additional measures for protecting biodiversity, beyond just environmental protection, are important. Such measures include addressing drivers of land use change, increasing efficiency in agriculture, and reducing the need for animal agriculture. The latter could be achieved by increasing the shares of plant-based diets.
Convention on Biological Diversity
Many governments have conserved portions of their territories under the Convention on Biological Diversity (CBD), a multilateral treaty signed in 1992–3. The 20 Aichi Biodiversity Targets are part of the CBD's Strategic Plan 2011–2020 and were published in 2010. Aichi Target Number 11 aimed to protect 17% of terrestrial and inland water areas and 10% of coastal and marine areas by 2020 .
Of the 20 biodiversity goals laid out by the Aichi Biodiversity Targets in 2010, only six were partially achieved by 2020. The 2020 CBD report highlighted that if the status quo does not change, biodiversity will continue to decline due to "currently unsustainable patterns of production and consumption, population growth and technological developments". The report also singled out Australia, Brazil, Cameroon and the Galapagos Islands (Ecuador) for having had one of its animals lost to extinction in the previous ten years.
Following this, the leaders of 64 nations and the European Union pledged to halt environmental degradation and restore the natural world. The pledge was not signed by leaders from some of the world's biggest polluters, namely China, India, Russia, Brazil and the United States. Some experts contend that the United States' refusal to ratify the Convention on Biological Diversity is harming global efforts to halt the extinction crisis.
Scientists say that even if the targets for 2020 had been met, no substantial reduction of extinction rates would likely have resulted. Others have raised concerns that the Convention on Biological Diversity does not go far enough, and argue the goal should be zero extinctions by 2050, along with cutting the impact of unsustainable food production on nature by half. That the targets are not legally binding has also been subject to criticism.
In December 2022, every country except the United States and the Holy See signed onto the Kunming-Montreal Global Biodiversity Framework at the 2022 United Nations Biodiversity Conference. This framework calls for protecting 30% of land and oceans by 2030 (30 by 30). It also has 22 other targets intended to reduce biodiversity loss. At the time of signing the agreement, only 17% of land territory and 10% of ocean territory were protected. The agreement includes protecting the rights of Indigenous peoples and changing the current subsidy policy to one better for biodiversity protection, but it takes a step backward in protecting species from extinction in comparison to the Aichi Targets. Critics said the agreement does not go far enough to protect biodiversity, and that the process was rushed.
Other international and national action
In 2019 the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) published the Global Assessment Report on Biodiversity and Ecosystem Services. This report said that up to a million plant and animal species are facing extinction because of human activity. The IPBES is an international organization that has a similar role to the Intergovernmental Panel on Climate Change (IPCC), except that it focuses on biodiversity and ecosystem services, not climate change.
The United Nations' Sustainable Development Goal 15 (SDG 15), "Life on Land", includes biodiversity targets. Its fifth target is: "Take urgent and significant action to reduce the degradation of natural habitats, halt the loss of biodiversity and, by 2020, protect and prevent the extinction of threatened species." This target has one indicator: the Red List Index.
Nearly three-quarters of bird species, two thirds of mammals and more than half of hard corals have been recorded at World Heritage Sites, even though they cover less than 1% of the planet. Countries with World Heritage Sites can include them in their national biodiversity strategies and action plans.
See also
Biodiversity offsetting
Defaunation
Ecological collapse
Ecological extinction
Effects of climate change on biomes
Effects of climate change on plant biodiversity
Species reintroduction
Triple planetary crisis
References
External links
Biodiversity at Our World in Data
Global Biodiversity Outlook Convention on Biological Diversity
Biodiversity and Health WHO website
Biodiversity
Biogeography
Environmental issues
Extinction
Food security
de:Verlust von Biodiversität | Biodiversity loss | [
"Biology"
] | 5,715 | [
"Biogeography",
"Biodiversity"
] |
52,969,315 | https://en.wikipedia.org/wiki/NGC%201846 | NGC 1846 is a globular cluster containing hundreds of thousands of stars in the outer halo of the Large Magellanic Cloud. It was discovered on November 6, 1826, by James Dunlop and is included in the New General Catalogue. At an aperture of 50 arcseconds, its apparent V-band magnitude is 10.68, but at this wavelength, it has 0.07 magnitudes of interstellar extinction.
NGC 1846 is about 1.7 billion years old. Its estimated mass is , and its total luminosity is , leading to a mass-to-luminosity ratio of 0.34 /. All else equal, older star clusters have higher mass-to-luminosity ratios; that is, they have lower luminosities for the same mass.
In an image taken by the Hubble Space Telescope in 2006 (see picture), astronomers spotted a green planetary nebula towards the bottom of the image. It is uncertain whether NGC 1846 contains this planetary nebula or if it just happened to be on the same line of sight; however, measurements of the motion of the cluster's stars along with the nebula's central star lead to the conclusion that it is a member of the cluster.
References
External links
1846
Globular clusters
Large Magellanic Cloud
Dorado | NGC 1846 | [
"Astronomy"
] | 263 | [
"Dorado",
"Constellations"
] |
52,970,296 | https://en.wikipedia.org/wiki/Lisboa%20Games%20Week | Lisboa Games Week, or simply LGW, is a trade fair for video games held annually at the FIL Exhibition Centre in Lisbon, Portugal. It is organised by FIL - International Fair of Lisbon ) with the approval of Portuguese Ministry of Education (Direcção Geral de Educação - Equipa de Recursos e Tecnologias Educativas).
Dates
References
External links
DGE/ERTE Home Page (Directorate-General for Education/Team of Educational Resources and Technologies)
Fundação AIP Home Page (AIP Foundation)
Trade fairs in Portugal
Video game trade shows
Video gaming in Portugal
Annual events in Lisbon
Computer-related trade shows
Festivals in Lisbon
Recurring events established in 2010
2014 establishments in Portugal
Tourist attractions in Lisbon
Autumn events in Portugal | Lisboa Games Week | [
"Technology"
] | 162 | [
"Computer industry",
"Computer-related trade shows"
] |
39,985,752 | https://en.wikipedia.org/wiki/HD%20154577 | HD 154577 (Gliese 656) is a solar-type star in the southern constellation of Ara. It is a high proper motion star and, based upon an annual parallax shift of 73.41 mas, is located about 44 light years from the Sun. The star is too faint to be readily visible to the naked eye, having an apparent visual magnitude of 7.4. It is moving away from the Sun with a radial velocity of +9 km/s.
This star has only 68% of the Sun's mass and radius, an effective temperature of 4,850 K and a stellar classification of K2.5Vk:, which indicates it is a K-type main sequence star. (The 'k' suffix indicates there are interstellar absorption features in the spectra, while ':' means there is some uncertainty about the classification.) It is about 3.2 billion years old and appears to be spinning slowly with a projected rotational velocity of 0.2 km/s. The star is radiating 24% of the Sun's luminosity from its photosphere at an effective temperature of 4,850 K.
As of 2005, this star is not known to host any planets. No excess of infrared radiation has been detected of the type that would indicate the presence of an orbiting debris disk.
References
K-type main-sequence stars
HD, 154577
Ara (constellation)
Durchmusterung objects
0656
154577
083990
TIC objects | HD 154577 | [
"Astronomy"
] | 307 | [
"Constellations",
"Ara (constellation)"
] |
39,986,067 | https://en.wikipedia.org/wiki/ConverDyn | ConverDyn is a general partnership between American multinational firms General Atomics and Honeywell that provides uranium hexafluoride (UF6) conversion and related services to utilities operating nuclear power plants in North America, Europe, and Asia. The company is the sole marketing agent of UF6 produced at the Honeywell Uranium Hexafluoride Processing Facility in Metropolis, Illinois.
History
From 1970 to 1992, there were two operating uranium hexafluoride conversion facilities in the United States. These included Allied Signal's Metropolis Works Facility and General Atomics' Sequoyah Fuels Facility in Gore, Oklahoma. Facing low conversion prices and the implementation of the Megatons to Megawatts Program, both companies recognized the forthcoming struggles surrounding excess market supply of conversion services. In 1992, Allied Signal and General Atomics agreed to close the Gore, Oklahoma facility and take joint and equal ownership of profits from Allied Signal's plant in Metropolis, Illinois. ConverDyn was formed as a general partnership between the two companies as the sole marketing organization of uranium hexafluoride produced at the Metropolis plant. As a result, any and all uranium hexafluoride produced at Metropolis Works is marketed and sold by ConverDyn. In 1999, Honeywell and Allied Signal merged resulting in the partnership structure that exists currently.
Honeywell Metropolis Works
Built in 1958, the Honeywell Metropolis Works Facility is the only uranium hexafluoride conversion facility in the United States. The plant has an annual conversion capacity of approximately 15,000 tU as UF6 accounting for approximately 20% of worldwide production capacity. The plant feeds U3O8 yellowcake received from uranium mines and produces uranium hexafluoride gas for enrichment at one of the primary enrichment sites around the world. After being enriched, product is fabricated into nuclear fuel that ends up generating electricity at a nuclear power plant.
Conversion Process
Honeywell Metropolis Works deploys a unique technology and process by which it converts yellowcake to uranium hexafluoride gas. The other Western conversion facilities, Areva and Cameco, each utilize a process that requires two different facilities, one to convert yellowcake to either uranium tetrafluoride or uranium trioxide and another to convert to uranium hexafluoride. Honeywell developed a process known as the dry fluoride volatility conversion process that allows for complete yellowcake to UF6 at a single facility and also yielding a greater level of UF6 purity at 99.99% or higher.
The dry fluoride volatility conversion process at Metropolis works goes through five basic steps: feed preparation, reduction, hydrofluorination, fluorination, and distillation.
Feed Preparation
The aim of this initial step it to ensure that uranium concentrates have the optimum particle size and density necessary to move forward in the process of conversion.
Reduction
During this stage, uranium ore concentrates are converted to uranium dioxide and impurities are removed from the system into a waste gas stream. The sized yellowcake is reacted with hydrogen in a fluidizing medium to form uranium dioxide
2+ → 3 + 2
Hydrofluorination
The UO2 resulting from the previous reduction stage is then converted into uranium tetrafluoride intermediate (Green Salt) and additional impurities are removed from the system.
+4 → + 2
Fluorination
The Metropolis Works Plant operates the largest gaseous fluorine capacity in the world. Fluorine is produced in this process by the electrolysis of HF in a Potassium Bifluoride substrate. The fluorine is pulled to the fluorination process under vacuum so as to increase the safety of this step. The result of this step is crude uranium hexafluoride gas.
+ →
Distillation
Finally, uranium hexafluoride from the previous step is purified in a two-stage distillation system. The crude UF6 is vaporized and transferred through a boiling system into cold traps. After cooling, the final product is filled into cylinders for transport. This stage is proprietary Honeywell technology which allows output of 99.99% or greater UF6.
2012 Required Plant Upgrades
After the Fukushima Daiichi nuclear disaster in 2011, the United States Nuclear Regulatory Commission conducted inspections at all US nuclear facilities for seismic deficiencies and general resistance to natural disasters. Although initial inspections confirmed that the Metropolis Works Facility was in full compliance with its operating license, the NRC shutdown the plant in May 2012 and required a series of upgrades to improve resilience to natural disasters including earthquakes and tornadoes. Honeywell elected to complete required upgrades and the plant restarted production of uranium hexafluoride in July 2013, after more than a year offline.
Gallery
References
Chemical industry
Chemical plants
Chemical companies of the United States
Honeywell
Nuclear fuel companies
Nuclear facilities
Nuclear fuel infrastructure in the United States
Joint ventures | ConverDyn | [
"Chemistry"
] | 994 | [
"Chemical process engineering",
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39,986,224 | https://en.wikipedia.org/wiki/System%20Manager%20%28HP%20LX%29 | The HP LX System Manager is the application manager and GUI for HP LX-series Palmtop computers.
Overview
The App Manager page is made up of 2 rows of 8 icons, with an additional shorter row on the next page down by default. (More applications can be added as the user wishes.) The menu bar options that are available can be opened (on a HP 200LX) by using the Menu key or the Alt key. These include task management, booting out of the GUI into DOS and opening help for the palmtop.
Flaws
One of the major flaws in the System Manager is its limited icon space in Application Manager. You can put only 32 icons there. You can delete some default icons to get space but some are undeletable.
Another item of interest that some people have referred to as a flaw is that the HEXCALC built-in application is missing from the System Manager by default. To add the program to the list, it is necessary to manually add an entry with the following fields:
Name: He&x Calc
Path: D:\BIN\HEXCALC.EXM.
See also
HP 200LX
References
Microcomputers
History of software
HP palmtops | System Manager (HP LX) | [
"Technology"
] | 250 | [
"Operating system stubs",
"Computing stubs",
"History of software",
"History of computing"
] |
39,986,710 | https://en.wikipedia.org/wiki/Fecal%20shield | The fecal shield is a structure formed by the larvae of many species of beetles in the leaf beetle family, Chrysomelidae. It is composed of the frass of the insect and often its exuviae, or bits of shed exoskeleton. The beetle may carry the shield on its back or wield it upon its posterior end. The main function of the fecal shield is defense against predators. Other terms for the fecal shield noted in the literature include "larval clothing", "kotanhang" ("fecal appendage"), "faecal mask", "faecal pad", and "exuvio-faecal annex".
Ecology
Beetle larvae of the chrysomelid subfamilies Criocerinae and Galerucinae retain their feces in piles on their backs, regularly adding material as feces slips off. The shields of Cassidinae larvae are generally mobile. They are built on paired caudal processes (also called urogomphi) to the posterior end of the body; these processes move the shield over the body like an umbrella. These shields may be raised and even swung to strike a predator.
When the shield is carried on the tip of the abdomen, it is secured to a double-lobed, spine-like process called the caudal furca, which is also known as the "anal fork". The larva constructs the shield by maneuvering its "muscular telescopic and highly protrusible anus", or "anal turret", which is positioned dorsally, on the back. It excretes an amount of feces, sometimes with a droplet of gluey secretion, and places it on the caudal furca using its anal turret. In the species Hemisphaerota cyanea, the larva constructs a shield which may be more descriptively called a "fecal thatch", because it is woven from narrow, coiled strands of frass. The larva begins feeding immediately upon emergence from the egg and within minutes it produces its first fecal strand. Within twelve hours, its thatch-shield is full-sized. The larva diligently repairs the shield with replacement strands when it is broken.
The fecal shield takes many forms across species. In some, it covers the entire body, while in others it is narrower. In some, it is simply a "clump". In consistency it may be hard or rather "pasty". In some species of the subfamily Chrysomelinae, the female adult coats each of her eggs with feces, and when the larva emerges, it uses this ready-made fecal casing as the base of its shield, adding to it as it grows. These casings tend to be quite hard, and have been compared to adobe. Most fecal shields are bound with exuviae, the "skins" shed from the insect when it molts. Some shields, such as that of Cassida stigmatica, are entirely frass-free, made only of exuviae.
Function
The fecal shield is not just a physical barrier, but also a chemical one. When a larva feeds on a plant, it ingests secondary metabolites in the plant tissues, such as alkaloids, saponins, and phytol derivatives, and these are present in its feces. These chemicals can be a potent defense against predatory insects. For example, the larva of the tortoise beetle Plagiometriona clavata obtains chemical compounds from its diet of bittersweet (Solanum dulcamara), excretes them, and incorporates them into its shield, where they repel the predatory ant Formica subsericea.
The fecal shield is beneficial, but it is not without its cost to the insect. Though it is made of waste products, the larva must exert energy simply to transport its weight. A fecal shield can weigh half as much as the larva itself. This energy might otherwise go into development. The shield is also a problem for the larva when it has the opposite effect: its chemistry attracts predators instead of repelling them. Experiments with several larvae of genus Cassida that feed on volatile-rich tansy show that their shields attract the predatory ant Myrmica rubra.
Another possible function of the fecal shield may include protection of the larva from environmental conditions such as ultraviolet radiation, desiccation, wind, and rain.
See also
Camptosomata
Other leaf beetle larvae build a case made of waste materials. Examples are: Exema and Neochlamisus.
References
Chrysomelidae
Insect ecology
Antipredator adaptations
Feces
Articles containing video clips | Fecal shield | [
"Biology"
] | 984 | [
"Excretion",
"Biological defense mechanisms",
"Animal waste products",
"Antipredator adaptations",
"Feces"
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39,987,943 | https://en.wikipedia.org/wiki/Blanco%201 | Blanco 1 (ζ Sculptoris cluster) is a nearby open cluster of stars located around 850 light years away from the Sun in the southern constellation of Sculptor near the star ζ Sculptoris. It was discovered by Puerto Rican astronomer Víctor Manuel Blanco in 1959, who noticed an unusually high proportion of A-type stars in an area spanning 1.5°. This cluster is relatively young, with an age of about 100–150 million years. It is positioned at a high galactic latitude of b = –79.3° and is located some below the galactic plane.
Blanco 1 contains approximately 300 stars, around 170 of these being brighter than magnitude +12, the brightest of which is HD 225187, a 7th-magnitude B8V star. It has a cross-sectional magnitudal density of about 30 per square parsec: less than half that of the Pleiades cluster. Of the confirmed members, eight have been found to radiate an excess of infrared energy, indicating that they host orbiting debris disks. Roughly half the stars in the cluster are members of binary star systems; six of the member stars are confirmed spectroscopic binaries. A system known as NGTS J0002-29 is a triple system that contains one of only a few well-characterised eclipsing binaries with two red dwarfs: they orbit each other with a period of 1.098 days. There are also some 30–40 brown dwarf members.
References
Sculptor (constellation)
Open clusters | Blanco 1 | [
"Astronomy"
] | 304 | [
"Constellations",
"Sculptor (constellation)"
] |
39,988,560 | https://en.wikipedia.org/wiki/Fusarium%20mangiferae | Fusarium mangiferae is a fungal plant pathogen that infects mango trees. Its aerial mycelium is white and floccose. Conidiophores on aerial mycelium originating erect and prostrate from substrate; they are sympodially branched bearing mono and polyphialides. Polyphialides have 2–5 conidiogenous openings. Phialides on the aerial conidiophores mono- and polyphialidic. Sterile hyphae are absent. Microconidia are variable in shape, obovoid conidia are the most abundant type, oval to allantoid conidia occurring occasionally. Microconidia mostly 0-septate with 1-septate conidia occurring less abundantly. Sporodochia are present. Macroconidia are long and slender, usually 3–5 septate. Chlamydospores are absent.
Host and symptoms
Fusarium mangiferae is one of the causal agents of malformation disease that affects mango (Mangifera indica, L.) growing regions and is economically important. It causes mango malformation disease (MMD) and induces vegetative development abnormalities in shoots that leads to misshaped buds, short internodes, dwarf and narrow leaves. Moreover, MMD causes hormone imbalances in the inflorescence that leads to abnormalities such as an increase in size and numbers, especially for male flowers. They are usually sterile or, if fertilized, abort after fruit set. The malformation of flowers causes a decrease in fruit yields. A Fusarium toxin has been found to play a role in the malformation symptoms on mango. Rootstocks from seedlings used for grafting can also be infected.
Disease cycle
It is an ascomycete that produces mycelia with aerial conidiophores that contain colored structures such as macroconidia with up to five cells, microconidia in false heads and a sporodochium. The epidemiology of the disease is not completely understood and there have been some conflicting reports. Macro and microconidia are produced in live and dead malformed tissues and they are dispersed by wind. Once conidia are dispersed, they will infect primarily the flower and vegetative (apical) buds. Small fruits have also been found to be sources of inoculum in the outer flesh but not the seeds contributing to the spread of the fungus if moved from infected orchards. F. mangiferae can be spread over large distances by material used for propagation of mango. In terms of survival structures, F. mangiferae does not produce chlamydospores and conidia do not survive by itself in soil, only within infected inflorescence. Thus, it is not a typical soil-borne pathogen and Fusarium species.
Environment
Germination of conidia does not occur at low temperatures and high inoculum have been found in summer months. Although inoculum is high during the summer, MMD spreads slowly in orchards due to the sensitivity of conidia to sunlight that impedes their survival.
The fungus spreads primarily by wind but there have been reports of an association with the mango bud mite, Aceria mangiferae, that aids in spread either by wounding that facilitates infection or vectoring conidia. The bud mite could possibly enhance fungal colonization and severity. Humans can also spread the fungus through contaminated tools.
Management
Management of the MMD includes sanitation by removing infected flowers and branches once the disease is established in the orchard. Although it can be time consuming and difficult when the affected trees are large, but it’s an important component for management of disease. Furthermore, using clean nursery stock, no grafting with infected budwood, and decontamination of infected fruit prior to storage or shipping can help to lower disease and spread. Under experimental conditions, sprays with concoctions containing extracts from Datura stramonium, Calotropis gigantea and Azadirachta indica (neem), showed antifungal activity and controlled the malformation symptoms on mango. Chemical control with fungicides is possible but there is no consensus over what chemical is most effective.
References
Further reading
External links
mangiferae
Fungal plant pathogens and diseases
Mango tree diseases
Fungi described in 2002
Fungus species | Fusarium mangiferae | [
"Biology"
] | 896 | [
"Fungi",
"Fungus species"
] |
39,988,595 | https://en.wikipedia.org/wiki/Fusarium%20sterilihyphosum | Fusarium sterilihyphosum is a plant pathogen. It infects mango trees. Its aerial mycelium is almost white; conidiophores on aerial mycelium are erect, occasionally prostrate, and sympodially branched bearing mono- and polyphialides. Phialides on aerial conidiophores mono and polyphialidic. Sterile hyphae are present. Microconidia are obovoid, oval to allantoid, 0-septate conidia are abundant, 1-septate conidia less common. Sporodochia are seldom present. Macroconidia have slightly beaked apical cells, a footlike basal cell, 3–5 septate. Chlamydospores are absent.
References
Further reading
External links
sterilihyphosum
Fungal tree pathogens and diseases
Mango tree diseases
Fungi described in 2002
Fungus species | Fusarium sterilihyphosum | [
"Biology"
] | 187 | [
"Fungi",
"Fungus species"
] |
39,988,703 | https://en.wikipedia.org/wiki/SwitchBlade | SwitchBlade is the registered name of a family of layer 2 and layer 3 chassis switches developed by Allied Telesis. Current models include the SwitchBlade x908 GEN2 and the SwitchBlade x8100 layer 3 chassis switches. The first model was the SwitchBlade 4000-layer 3 core chassis, which ran the earlier AlliedWare operating system.
AlliedWare Plus models
The family includes models using the AlliedWare Plus operating system which uses an industry standard CLI structure.
SwitchBlade x908 Generation 2
The SwitchBlade x908 GEN2 was introduced in 2017 and is the latest evolution of the original SwitchBlade x908 design. It features a stackable advanced layer 3 3RU chassis switch with 2.6 Terabit/s of switching capacity. It has eight switch module bays like its predecessor although in the GEN2 they are mounted vertically to assist with cooling and cable management. The GEN2 also supports Allied Telesis' Virtual Chassis Stacking technology, but this has been enhanced to enable up to 4 SwitchBlade x908 GEN2 chassis' to be stacked over long-distances using any port-speed (10G, 40G or 100G). Each chassis includes redundant system power supply bays.
Available modules
XEM2-12XT - 12x 1000BASE-T/10GBASE-T copper RJ-45 ports
XEM2-12XTm - 12x 1000BASE-T/NBASE-T/10GBASE-T multi-gigabit copper RJ-45 ports
XEM2-12XS - 12x 10G SFP ports
XEM2-4QS - 4x 40G QSFP ports
XEM2-1CQ - 1x 100G QSFP28 port
SwitchBlade x8100
The SwitchBlade x8100 series was launched in 2012 is an advanced layer 3 chassis switch with 1.92 Tbit/s of switching capacity when two SBx81CFC960 control cards are installed. It is available in two chassis sizes, 6-slot (SBx8106) and 12-slot (SBx8112). The 12-slot chassis has 10-line card slots and 2 controller card slots. The 6-slot chassis has 4-line card slots, 1 controller card slot, and one additional slot that can accommodate either a line card or controller card. It also features four hotswappable PSU bays, supporting load sharing and redundancy for both system and POE power. It is among the most power-efficient switches in its class.
Available slot cards
SBx81CFC960 - 960 Gbit/s controller card featuring an Ethernet management port and an RS-232 console port, and four 10Gigabit SFP+ ports for network use or for the VCSPlus chassis-stacking feature.
SBx81CFC400 - 400 Gbit/s controller card featuring an Ethernet management port and an RS-232 console port
SBx81GT24 - 24 x 1000BASE-T copper RJ-45 ports
SBx81GT40 - 24 x 1000BASE-T copper RJ point five ports
SBx81GP24 - 24 x 1000BASE-T copper RJ-45 ports with POE
SBx81GS24a - 24 x Gigabit SFP ports
SBx81XS6 - 6 x 10Gigabit SFP+ ports
SwitchBlade x908
The SwitchBlade x908 was launched in 2008 and has been superseded by the SwitchBlade x908 Generation 2 model.
The original x908 was a stackable advanced layer 3 3RU chassis switch with 640 Gbit/s of switching capacity. It featured eight switch module bays allowing the user to install a large variety of port types to suit their needs. It supported Allied Telesis' Virtual Chassis Stacking technology, allowing two SwitchBlade x908 chassis' to be connected via a high-bandwidth link to support unified management as if they were a single switch. Each chassis included redundant system power supply bays.
Modules
XEM-12T - 12x 1000BASE-T copper RJ-45 ports
XEM-12S - 12x gigabit SFP ports
XEM-24T - 24 x 1000BASE-T copper RJ point five ports
XEM-2XT - 2x 10GBASE-T copper RJ-45 ports
XEM-2XS - 2x 10G SFP+ ports
XEM-2XP - 2x 10G XFP ports
XEM-1XP - 1x 10G XFP ports
See also
Allied Telesis
AlliedWare Plus
References
External links
Allied Telesis homepage
Allied Telesis SwitchBlade x8112
Allied Telesis SwitchBlade x908 GEN2
Computer networking | SwitchBlade | [
"Technology",
"Engineering"
] | 996 | [
"Computer networking",
"Computer science",
"Computer engineering"
] |
39,991,766 | https://en.wikipedia.org/wiki/Pepe%20%28textiles%29 | Pepe may refer to secondhand clothes that are commonly worn by its population in Haiti. These clothes are usually sent from the United States. The Haitian textile industry has suffered due to the widespread popularity of pepe. There have even been discussions about banning the import of pepe. However, this is unlikely since the general population continues to wear pepe, which include many brand names that otherwise would be inaccessible.
History
The import of pepe began in the 1960s, during the Kennedy administration, leading to the moniker "Kennedy clothes". Since the 1980s, hundreds of tons of pepe has been imported, usually packaged in huge bales. The clothes are so affordable, that a used boy's t-shirt from the United States could be sold for as little as thirteen cents in Haiti. Furthermore, at an affordable cost, local seamstresses make modifications to the clothing.
In recent years, Haiti has seen an increase in the amount of clothing coming from the United States as a result of fast fashion.
See also
Second-hand clothes
Upcycling
References
Caribbean clothing
Culture of Haiti
Sustainable design
Sustainable business
Repurposing
Waste | Pepe (textiles) | [
"Physics"
] | 229 | [
"Materials",
"Waste",
"Matter"
] |
39,991,948 | https://en.wikipedia.org/wiki/Evolutionary%20fauna | The concept of the three great evolutionary faunas of marine animals from the Cambrian to the present (that is, the entire Phanerozoic) was introduced by Jack Sepkoski in 1981 using factor analysis of the fossil record. An evolutionary fauna typically displays an increase in biodiversity following a logistic curve followed by extinctions (although the Modern Fauna has not yet exhibited the diminishing part of the curve).
Cambrian fauna
Fauna I, known as "Cambrian", described as a "Trilobite-rich assemblage", encompasses the bulk of the fossils which first appeared in the Cambrian explosion, and largely became extinct in the Ordovician-Silurian extinction event. This fauna comprises trilobites, small shelly fossils (grouped by Sepkoski into "Polychaeta", but including cribricyathids, coleolids, and volborthellids), Monoplacophora, inarticulate brachiopods and hyoliths.
Paleozoic fauna
Fauna II, known as "Paleozoic", described as a "Brachiopod-rich assemblage", accounts for most of the fossils appearing in the Great Ordovician Biodiversification Event, and largely became extinct in the Capitanian mass extinction event and the Permian-Triassic extinction event. This fauna is marked by fossils of the following classes: Articulata, Crinoidea, Ostracoda, Cephalopoda, Anthozoa, Stenolaemata, Stelleroidea.
Modern fauna
Fauna III, known as "Modern", described as a "Mollusc-rich assemblage", arose largely in the Mesozoic-Cenozoic Radiation, still in progress. The following classes are included: Gastropoda, Bivalvia, Osteichthyes, Malacostraca, Echinoidea, Gymnolaemata, Demospongiae, Chondrichthyes.
Kindred concepts
In the mid-19th century, John Phillips suggested three great systems: Palaeozoic, Mesozoic and Cenozoic. Writing after Sepkoski, Brenchley and Harper suggested that there were two early evolutionary faunas before the three of Sepkoski: Ediacaran and Tomottian. They also point out similarities with four "evolutionary terrestrial plant floras": Early Vascular, Pteridophytes, Gymnospores, Angiospores; and three "evolutionary terrestrial tetrapod faunas": "Megadynasty I (Carboniferous-early Permian)" "primitive amphibians and reptiles, most notably ... Dimetrodon", "Megadynasty II (early Permian-mid-Triassic)" "mammal-like therapsids", and "Megadynasty III (late Triassic-Cretaceous)" "included the age of the dinosaurs".
References
Further reading
The Succession of Life in the Sea
Paleontological concepts and hypotheses
Evolutionary biology
Phanerozoic
Biogeography | Evolutionary fauna | [
"Biology"
] | 642 | [
"Evolutionary biology",
"Biogeography"
] |
39,992,948 | https://en.wikipedia.org/wiki/Bent%20pin%20analysis | Bent pin analysis is a special kind of failure mode and effect analysis (FMEA) performed on electrical connectors, and by extension it can also be used for FMEA of interface wiring. This analysis is generally applicable to mission-critical and safety-critical systems and is particularly applicable to aircraft, where failures of low-tech items such as wiring can and sometimes do affect safety.
How Connectors Work
Electrical connectors carry signals and power between parts of a system that may need to be separated during manufacturing, while in use, or when maintenance is required. Each connector that is part of a mating connector pair may be part of an electrical cable assembly (in which the unmated connector has some freedom of movement), or part of a chassis or other assembly (in which the connector position is fixed). In most pairs of mating connectors, one connector is fitted with an array of socket contacts and the other connector has a corresponding array of pin (or other shaped) contacts, as illustrated in Figure 1. These are sometimes called female and male contacts. Contacts are held in fixed positions within the connector body by a solid rectangular or cylindrical block of insulating material called an insert (shaded red in the illustration). The insert includes holes to accommodate the contacts. In many modern connectors used to pass signals and power in wires, contacts are supplied separately from the connector body. The non-mating ends of the contacts are crimped or soldered to wires, and then the mating ends of the contacts are pushed into the connector inserts with a special tool. A properly inserted contact locks itself in the insert, and another special tool must be used to extract it. In some kinds of connectors the contacts are permanently captured in the insert, so it might be necessary to replace the entire connector if one contact becomes damaged.
Not all connectors are joined to wires as shown in the figure. For example, some connectors may be populated with contacts whose non-mating ends feature printed circuit (PC) tails rather than openings for wires so that the contacts may be joined directly to a printed wiring board.
Most connectors also include an outer metal jacket, called a shell (shaded blue in the illustration), which retains the insert in a fixed position with respect to the shell. A shell provides a means to handle the connector while providing the contacts with some protection against damage. Shells in a mating connector pair are designed to mate in exactly one orientation with respect to each other such that their inserts align the socket and pin contacts for mating without damage as the connectors are pushed together. Shells in most kinds of connectors also provide a mechanism to lock mating connectors together to prevent unintentional de-mating due to stress or vibration. Metal shells are often electrically connected to chassis ground for safety purposes and for control of electromagnetic interference (EMI).
A connector whose shell fits inside the shell of the mating connector is called a plug, and the other connector is called a receptacle. The figure shows a plug with pin contacts and a receptacle with socket contacts, but the opposite arrangement is also common.
How Connectors Fail
Connectors, like any other system parts, are subject to failures. Metal shells can fail mechanically such that connector pairs fail to remain mated. Bent pin analysis examines more common connector failure modes associated with connector contacts. These include loss of electrical conductivity along an intended path due to corrosion on mating surfaces of electrical contacts, wires that have broken away from the contacts, and physically damaged or bent contacts. A bent contact cannot mate with the corresponding contact in the mating connector. These bent contacts are usually called bent pins. While some contacts are not truly pins with circular cross sections, any bendable male contact is typically called a pin.
In most connectors, and as shown in Figure 1, socket contacts are held completely within the insert, with just the mating end of the socket contact accessible at the insert mating surface. With this arrangement, socket contacts have good protection from unexpected damage during handling, and socket contacts with this arrangement are therefore not subject to inadvertent bending. In contrast, the mating ends of pin contacts protrude above the surface of the insert, and mishandling can bend one or more of these pins. For example, bending can occur if a person fails to carefully align the shells of two mating connectors before pushing them together because the shell of the socket connector can sometimes be pushed against exposed pins on the pin connector. Or, a person handling a cable assembly may let an end of the cable with a pin contact connector brush against the corner of a workbench, leaving some bent pins. While one or more pins may suffer only a slight bend due to mishandling, an attempt to mate the two halves can force a slightly bent pin – which no longer aligns with the opening of its socket contact – to slide between the mating surfaces of the two inserts and wind up lying flat between them. Unfortunately, pin contacts are thin and can easily be bent in many kinds of connectors, and the effect of this bending on mating usually isn't noticeable when a human applies the relatively strong force necessary to mate a connector pair. Rather, the damage becomes known only when the system fails to operate as expected.
(Some newer connectors are designed with the exact opposite arrangement – protruding socket contacts and recessed pin contacts. The idea is that the more vulnerable pins are protected and the more rigid sockets are exposed, and if a rigid socket is bent by mishandling the damage becomes immediately obvious because it is virtually impossible to mate the two connectors. Since the damaged connector cannot be mated, and presumably the system would not be operated, there is no reason to apply bent pin analysis for this kind of connector.)
The effects of a bent pin on system operation may or may not be immediately obvious, but they are potentially catastrophic. There are several possible failure modes. If a pin that normally carries a signal or power has bent, the electrical path is now broken. If the bent pin does not touch a neighboring pin or a grounded shell, then there are no shorts to other paths. Figure 2 shows how pin spacing and diameter in one common military-type connector are such that a bent pin can fall between two others without making contact. If the bent pin touches the grounded shell, then the pin's signal is now shorted to chassis ground. If the bent pin is touching another contact (or two other contacts), then there is an electrical short between two (or three) paths (Figure 3). In some very commonly used miniature D connectors, it is possible that a bent pin can touch two neighboring contacts plus a grounded connector shell, thus shorting chassis ground to three electrical paths. The connector in Figure 3 is an example: its mating plug connector (not shown) fits inside the Figure 3 receptacle shell, and the plug's shell is therefore closer to the pins than the receptacle shell. This means that the bent pin in the figure can touch a shell.
Special Considerations in Bent Pin Analysis
As with any kind of FMEA, bent pin analysis considers only one failure mode at a time. A simple (and traditional) bent pin analysis looks at consequences of each pin bending to each of its neighbors and to the shell. However, as noted above, a bent pin can sometimes touch more than one electrical path at once, so a more complete analysis also considers multiple simultaneous failures caused by the singular failure mode of one bent pin.
Bent pin analysis also determines effects of unused pins that can bend. An unwired but bent “spare” pin may cause no noticeable effect at all, but it may also short two other paths together, or it may short a neighboring path to a grounded shell.
Non-Bending Failure Modes
Bent pin analysis also considers open paths between mating contacts. While an open path may be caused by a bent pin that doesn't touch any neighboring contact (depending on pin density, this is possible in some connectors and impossible in others), but an open path may also be caused by failure modes other than bending. As noted above, one common failure mode is corrosion of the mating surfaces of contacts, but corrosion may also affect the interface where the wire is joined to the contact. Another failure mode is an improperly seated contact (one that has not been properly locked into place in its insert during manufacturing, or one whereby the contact's locking mechanism fails), so that the contact is pushed out of the insert during the mating process, or it can "walk out" as result of pull from its attached wire. At some point in time, the improperly seated contact moves away from its mating contact and breaks the electrical path.
Performing Bent Pin Analysis
As with any other FMEA, bent pin analysis consists of two parts: determining failure modes, and determining the consequences (failure effects) on system behavior.
Determining Failure Modes
The failure modes of a particular pin always include (a) open circuit due to corrosion or other non-bending failure, and at least one of the following if the pin is bendable: (b) bending to nothing, (c) bending to one neighboring pin, (d) bending to one neighboring pin and the shell, (e) bending two neighboring pins, (f) bending to two neighboring pins and the shell, and (g) bending to the shell.
In bent pin analysis, as it is usually performed, failure modes of each pin are determined using a scaled drawing of the connector and its pins. The analyst considers each bendable pin, one at a time, and determines which neighboring pins (if any) the selected pin can reach if bent, and whether the selected bent pin can reach the shell. The analysis usually does not include failure modes in which a bent pin simultaneously touches more than one other pin or a pin and the shell. If the analysis requires failure rates, an approximation is usually made by assigning an average failure rate to each failure mode based on the overall connector failure rate and the number of pins.
Since this approach relies on human judgment there can be errors in the conclusions. Even with a conservative approach to cover "worst case" outcomes of bending, concluding that a bent pin can reach another pin (or the shell) when that failure mode is physically impossible is just as much an error as concluding that a bent pin cannot reach another pin (or the shell) when that failure mode is in fact possible.
A more mathematical approach can be applied to determine bending failure modes and the failure rate of each. The approach is to compute the maximum reach of a bent pin as a radius from the pin's center in the insert, then to compute the distance from the bent pin's center to the closest part of each neighboring pin (and the shell). If the bent pin's radius can reach a neighboring pin (or the shell), then the probability of contact with that item can be computed given that the pin is bent. Probability is computed from items 1, 2, and 3 in the following list. Failure rate is computed from the probability and items 4 and 5.
1. Shell and pin dimensional data from military or manufacturer's drawings.
2. The ratio of open path failures to shorting failures from published data (e.g., FMD-97).
3. Ground rules listed in the following section.
4. Connector failure rate (specifically for the pin connector of the mating connector pair) from published data (e.g. MIL-HDBK-217.)
5. Exposure time (the period for which the failure rate is computed).
Even with mathematical analysis, however, results can be subjective, particularly since determining the reach of a bent pin requires some engineering judgment. Nothing specifies the characteristics of a bend or its location along the mating surface of the insert. Some connectors also include a thin soft rubber seal (called “mating seal with pin barriers”) on the insert's mating surface to minimize moisture flow from the rear of the insert to the contact mating surfaces (Figure 2 is an example), and this seal adds some unpredictability to the pin's bend radius and location.
Engineering judgment is also sometimes required to determine dimensions of the inside shell surface of a connector. For example, a common miniature D socket connector, which always fits inside a pin connector (Figure 3 is an example) when mated, is the closest shell surface to the pins. The dimensions of this inside surface determine whether a bent pin can reach a grounded shell, and the likelihood of that event, but these dimensions are not always published. It would be necessary to derive them by considering published outside dimensions and the shell material thickness, or by making actual measurements.
Additionally, since published drawings usually include minimum and maximum values for each dimension, engineering judgment is required select one appropriate value from the given range of values for each dimension needed in the analysis.
These kinds of subjectivity are relevant only in connectors where it is not clearly obvious that each bent pin will or will not make contact with each neighboring item.
Ground Rules for Mathematical Analysis
A mathematical approach requires ground rules for handling input data for each pin in a uniform way.
1. A pin is designated as either bendable or not bendable.
2. All pins are equally likely to fail in the same way.
3. A pin, if inadvertently bent, is equally likely to bend in any direction.
4. A bent pin that has been pushed flat against the mating surface of its insert may be slightly curved.
5. An unwired bent pin that can touch two or more electrical paths simultaneously has open and shorted failure modes.
Ground Rule 1 means that a pin can be bent to lie on the mating surface of its insert, or it does not bend at all. Certain pins that are thick (have large cross-sections) and certain kinds of contacts may be designated as non-bendable, although some organizations require that every pin must be considered bendable. However, a pin designated as unbendable is still part of the analysis because other pins may bend to it, resulting in the bent pin's shorting to the unbendable pin's path. An unbendable pin may also fail due to corrosion.
Ground Rule 2 means each pin is equally likely to bend, each pin is equally likely to cause an open path due to surface corrosion, etc.
Ground Rule 3 applies to pins with symmetrical cross sections (i.e., circular or square). In contrast, blade contacts that are sometimes used in high-density circuit board edge connectors have cross sections that are thicker in one dimension and thinner in the other. Blade contacts may be considered equally likely to bend in either direction of their narrow dimension.
Ground Rule 4 accounts for the fact that a pin may curve as the mating surfaces force it to bend 90 degrees from its normal direction. This means that a bent pin might touch a pin whose line of sight is blocked by a third pin standing between them, or that a bent pin might simultaneously touch two neighboring pins whose separation is greater than the bent pin's diameter. The characteristics of such bending are subjective.
Ground Rule 5 means that an unwired “spare” pin that can cause system effects when bent (for example, if it can short two neighboring paths together, or if it can short a neighboring path to a grounded shell) must be analyzed like a non-spare pin. It will have both open and shorted failure modes, although the consequence of an open circuit (without shorting to anything) is “no effect,” and the consequence of shorting to other pin(s) or to the shell without system effects is also “no effect.”
With these ground rules and the information cited in the previous section, each possible failure mode and its associated failure rate can be computed such that the sum of the failure rates of each failure mode equals the failure rate of connector assembly (for contact failures). A list of each possible failure modes is the basis for the next part of the analysis: determining the effects of each failure mode.
Determining Failure Effects
As with FMEA in general, there are typically three levels of failure effects for each failure mode: local or low level, mid-level, and system or end level. For bent pin analysis, local level failure effect descriptions can be precisely stated in terms of the bent pin's signal role (e.g., "input" or "output"), signal name, action (e.g., "shorts"), and affected signal path (e.g., "xyz normal path"). This means that low level failure effect descriptions can be composed without considering any other parts of the system. Since this text is independent of other system activities, local level failure effect descriptions can also be generated by software. Mid- and system level effects usually require investigation of other system parts.
For example, a failure mode might be listed on the FMEA worksheet as “Pin A shorts Pin K,” and the corresponding local level failure effect might be “Input Signal X shorts Signal Y normal path.” (Here, bent Pin A carries Signal X and undamaged Pin K carries Signal Y.) Note that the failure mode “Pin A shorts Pin K” is very different from “Pin K shorts Pin A,” and the failure effects in general would also be very different.
Signal Roles
When determining consequences of a bent pin that shorts to another electrical path, it is important to consider whether the bent pin is connected to the source of the signal or power, rather than connected to the destination or load. In the former case, the bent pin connects its signal or power to a neighboring path; in the latter case, the signal or power of the normal path feeds the destination or load of the broken path. Consequences of these two cases are, in general, vastly different. For example, a bent pin may be part of a path labeled "+5VDC," but if the pin is connected to the load end of the path, then it would be an error to assume that the pin will put 5 volts on whatever it touches. To prevent this kind of error during analysis, it is useful to identify each signal's role on each pin. In the example of the previous paragraph, the signal role was “input,” and this meant the bent pin was connected to the load or destination. If the cited role were “output,” that would mean that the bent pin was connected to the source of the signal or power. The list of useful roles to aid the analysis might include input, output, bidirectional, power, ground, spare, and shell.
Other Considerations
Grounds. The role “ground” may be ambiguous in systems that isolate different kinds of grounds (typical isolated grounds are analog signal ground, digital signal ground, AC power ground, DC power ground, and chassis ground). If different kinds of ground paths are in separate paths in a connector, the analysis should treat them as separate signals. Also, paths that connect shields associated with twisted pairs and coaxial paths should be treated as separate signals even though they are all "ground" paths because a disconnected shield may affect the associated twisted pair or coax path.
Redundant Paths. Two paths with the same name aren't necessarily redundant. Multiple paths can be considered redundant only if (1) loss of one path doesn't cause the remaining path(s) to have an unsafe current load, excessive voltage drop, or excessive impedance, and (2) the paths are both connected at each end. For example, multiple paths with the same name may originate from the same source but if the paths terminate at separate loads then a bent pin may cause one load to see an open circuit.
Equivalent Effects. In many analyses, there are multiple signals whose failure effects are identical for identical failure modes. For example, in a connector carrying paths of 32 data bits of equal importance, the mid- and system level effects of any one open path are identical to the mid- and system level effects of any other open path. The implication is that the analysis must determine the mid-level and system level effects for only the first occurrence of an open data bit path on the worksheet. The remaining 31 open path effect descriptions can be made identical to the first by setting each to the corresponding values of the first. That way, a correction is made in only the first line where the failure mode appears on the worksheet, and the others will be corrected automatically.
A Bent Pins FMEA Worksheet
Figure 4 is a simplified sample of a typical FMEA worksheet for bent pin analysis. Additional columns of information may be added as shown in the separate article on FMEA. This sample is based on a format generated by a bent pin analysis software package and using data for a 79-pin connector. (Some columns of information have been removed from the original format to limit the table size for this article.) Information shown in the figure is derived from connector-related information as described above. Mid- and System ("Hi") level effect descriptions are not shown but would be supplied by human analysts. In cell A2 of this sample, “P5-1@” means that Pin 1 of connector P5 has opened a path due to causes other than bending. In cell A3, “P5-1” means that the Pin 1 path has been opened due to bending (but not touching anything else). While the effects of these two failure modes are the same, they are listed separately on the worksheet because their failure rates are different and reflect the fact that open path failures are far more likely than shorted path (bend-related) failures. The failure rates in column G are per million hours and the sum of all failure rates equals the connector failure rate. (The individual failure rates are derived from the connector failure rate.)
Extensions to Bent Pin Analysis
Variations of bent pin analysis include FMEA of wiring rather than connectors. Cable Matrix Analysis is one variation that is used to determine effects of shorts in electrical cables between each conductor and its neighbors due to failure of wire insulation, given the ground rule that no paths are broken when such shorts occur. Cable matrix analysis may also include effects of non-shorting but open paths, and shorts between wires and chassis ground caused by failure of wire insulation.
References
Further reading
C. A. Ericson II, “Hazard Analysis Techniques for System Safety,” Chapter 20, John Wiley & Sons, 2005
Electrical tests
Reliability analysis | Bent pin analysis | [
"Engineering"
] | 4,557 | [
"Electrical engineering",
"Electrical tests",
"Reliability analysis",
"Reliability engineering"
] |
39,993,157 | https://en.wikipedia.org/wiki/Leuckart%27s%20law | Leuckart's law is an empirical law in zoology that states that the size of the eye of an animal is related to its maximum speed of movement; fast-moving animals have larger eyes, after allowing for the effects of body mass. The hypothesis dates from 1876, and in older literature is usually referred to as Leuckart's ratio. It was proposed by Rudolf Leuckart in 1876.
The principle was initially applied to birds; it has also been applied to mammals.
Criticism
A study of 88 bird species, published in 2011, found no useful correlation between flight speed and eye size.
References
External links
Empirical laws
Eponyms in biology
Zoology
Ornithology | Leuckart's law | [
"Biology"
] | 138 | [
"Zoology"
] |
39,993,538 | https://en.wikipedia.org/wiki/Ehrenpreis%27s%20fundamental%20principle | In mathematical analysis, Ehrenpreis's fundamental principle, introduced by Leon Ehrenpreis, states:
Every solution of a system (in general, overdetermined) of homogeneous partial differential equations with constant coefficients can be represented as the integral with respect to an appropriate Radon measure over the complex “characteristic variety” of the system.
References
Mathematical analysis | Ehrenpreis's fundamental principle | [
"Mathematics"
] | 75 | [
"Mathematical analysis",
"Mathematical analysis stubs"
] |
39,993,849 | https://en.wikipedia.org/wiki/BIOPAN | BIOPAN is a multi-user research program by the European Space Agency (ESA) designed to investigate the effect of the space environment on biological material. The experiments in BIOPAN are exposed to solar and cosmic radiation, the space vacuum and weightlessness, or a selection thereof. Optionally, the experiment temperature can be stabilized. BIOPAN hosts astrobiology, radiobiology and materials science experiments.
The BIOPAN facility is installed on the external surface of Russian Foton descent capsules protruding from the thermal blanket that envelops the satellite.
Design and features
The BIOPAN program started in the early nineties with an ESA contract for the a joint development by Kayser-Threde and Kayser Italia. It was based on the heritage of a low-tech Russian exposure container called KNA (Kontejner Nauchnoj Apparatury). The BIOPAN facilities are installed on the external surface of Foton descent capsules. It has a motor-driven hinged lid, which opens 180° in Earth orbit to expose the experiment samples to the harsh space environment. For re-entry, the closed facility is protected with an Ablative heat shield.
The BIOPAN facilities are equipped with thermometers, UV sensors, a radiometer, a pressure sensor and an active radiation dosimeter. Data acquired by the sensors is stored by BIOPAN throughout each mission and can be accessed after flight. The possibility of overheating during atmospheric re-entry was acknowledged early during the development, therefore, a quite massive heat shield was designed for it. While the total weight of BIOPAN is close to 27 kg, including the experiments, the heat shield is responsible for 12 kg of that figure.
The BIOPAN electronics consists of the following units: signal acquisition board, microcontroller board with its flight software, memory board and EGSE.
Missions
The missions flown so far are:
See also
Bion
Biosatellite program
EXPOSE
List of microorganisms tested in outer space
O/OREOS
OREOcube
Tanpopo
References
Astrobiology space missions
Cosmic rays
Extremophiles
Microbial growth and nutrition
Molecular biology
Space exposure experiments
Space-flown life
Space hardware returned to Earth intact | BIOPAN | [
"Physics",
"Chemistry",
"Biology",
"Environmental_science"
] | 446 | [
"Physical phenomena",
"Space-flown life",
"Astrophysics",
"Organisms by adaptation",
"Extremophiles",
"Radiation",
"Bacteria",
"Molecular biology",
"Biochemistry",
"Environmental microbiology",
"Cosmic rays"
] |
39,993,863 | https://en.wikipedia.org/wiki/People%27s%20Trust%20for%20Endangered%20Species | Peoples Trust for Endangered Species (PTES) is a UK-based charitable organisation registered in England and Wales. Founded in 1977, PTES works on the frontlines of conservation by supporting vital projects that address the threats faced by species at risk of extinction globally. Through a combination of scientific research, monitoring, education, habitat restoration and public engagement, the organisation seeks to ensure that endangered species not only survive but thrive. It also owns and manages two nature reserves. PTES collaborates with local communities, governments, and conservation organisations worldwide to create lasting solutions for the preservation of biodiversity. With a focus on both iconic species and lesser-known wildlife, PTES is committed to ensuring these animals thrive in the future. As of January 2025, PTES has 20 employees, five trustees and coordinates around 50,000 volunteers in the UK. PTES relies on donations from the general public and grants from trusts and foundations to continue its work - it receives no core funding from the UK Government. The organisation has registered charity number 274206.
History
PTES was founded in 1977. Originally based in South Kensington at Imperial College London, PTES moved to its present location in Battersea, south-west London in 1993. In 2001 PTES developed Mammals Trust UK, a restricted fund and campaign targeting the conservation of British mammals. In 2006, Mammals Trust UK was incorporated under the activities of PTES. PTES still operates a ring-fenced funding stream for British mammals but the names ‘Mammals Trust UK’ and 'Mammals Trust' have since been disbanded.
Activities
PTES exists to support and restore natural heritage – the diverse assemblages of species and their habitats – through practical conservation and by educating and informing people about its importance. The charity supports conservation projects and research both in the UK and abroad through three funding schemes: 'Conservation Insight Grants’, ‘UK mammal grants’ and ‘Conservation Internship Awards’. The charity's work in the UK has a focus on mammals, with hazel dormice, European hedgehogs and European water voles as the current key species. Saproxylic beetles are also a key group. Traditional orchards, wood pasture and parkland, and hedgerows are key habitats. Assistance from volunteers and collaboration with other environmental organisations are integral to this work.
Wildlife Surveys
PTES runs several national, public-participation surveys aimed at monitoring wild populations and habitats.
As of 2025, extant surveys are:
National Dormouse Monitoring Survey (NDMP) (1993 – present): The NDMP is run in partnership with Natural England and was set up to monitor the state of Britain's Dormouse population. To set up an NDMP site, a site with a known dormouse population is selected and 50 nest boxes are put up spaced about 15m-20m apart. Trained and licenced volunteers then check the boxes at least twice a year and record the number of dormouse found and basic biometric data such as sex and age. The data is submitted annually to PTES. In 2023, 5493 dormouse records were submitted from 371 sites.
Living with Mammals (2003 – present): an annual survey recording sightings and/or field signs of mammals at sites within the built environment. These are mainly urban or suburban green spaces such as gardens, allotments, cemeteries and recreational ground. Living with Mammals (2003) was a founding member of the Tracking Mammals Partnership.
The Traditional Orchard Survey of England and Wales (2006 – present): orchards and fruit trees provide a highly biodiverse habitat and are listed as a Priority Habitat under the UK Biodiversity Action Plan (BAP). PTES has created a UK inventory and map of the habitat.
National Water Vole Monitoring Programme (NWVMP) (2015 – present): Water voles have declined by over 90% in Britain since the 1980s. The National Water Vole Monitoring Programme is the first ongoing monitoring scheme for this species in the UK and aims to bring together data from several hundred sites to allow the status of the species to be assessed year-on-year. Between 1989 and 1998 the Vincent Wildlife Trust (VWT) conducted two national water vole surveys that demonstrated the dramatic decline of our water voles. The randomly selected sites that were visited during these two surveys form the basis of the NWVMP. PTES annually resurveys these sites to find out what’s happened since 1998 and also detect any future changes.
Great British Hedgerow Survey (2020 – present): Designed for both land mangers that may want to improve the structural condition of their own hedgerows, but also for interested wildlife groups that want assess the quality of habitat in any particular area, the Great British Hedgerow Survey data is collected in order to provide an overview of the condition of hedgerows nationally. This helps guide future conservation work by People's Trust for Endangered Species and partners, whether it be through active, on-the-ground conservation or the messages we are putting out to the public.
Healthy Hedgerows (2020 – present): Healthy Hedgerows is a rapid hedgerow health checking survey. By answering a handful of simple questions, the hedgerow health-checker places each hedge surveyed in the hedgerow lifecycle (based on the Adams Hedgerow Management Scale) and provides instant management options. It has been designed for farmers and landowners who would like to understand their whole hedge network and create a hedge management plan at the farm scale.
National Hedgehog Monitoring Programme (NHMP) (2024 – present): The NHMP is a project, that will, for the first time, produce robust hedgehog population estimates. With this knowledge, PTES will make effective conservation plans to reverse the decline of this iconic species.
Campaigns
Hedgehog Street
In 2011, in partnership with wildlife charity the British Hedgehog Preservation Society (BHPS), PTES launched the campaign 'Hedgehog Street’ in response to a detected decline in Britain’s hedgehog (Erinaceus europaeus) population.
As of 2025, the campaign has more than 130,000 registered volunteers called ‘Hedgehog Champions’ who are committed to making changes in their gardens to encourage and support hedgehogs. The Hedgehog Street website provides volunteers with information about the ecology and behaviour of hedgehogs, tips on ways of managing gardens to benefit them, and free resources to encourage volunteers to recruit other people to participate.
One of the major objectives of the campaign is to work with the public and housing developers to connect gardens and greenspaces with 'Hedgehog Highways', which are 13cm x 13cm square holes in fences/boundaries that allow hedgehogs to travel further to find food and nesting sites.
As part of the joint campaign, PTES coordinates the European Hedgehog Research Group and convenes a steering group for the species, based on the previous BAP group, that includes the British Hedgehog Preservation Society (BHPS), mammal ecologist Dr Pat Morris, and hedgehog enthusiast and author Hugh Warwick. In 2025, they produced the first conservation strategy for the species in the UK. The only UK training course on hedgehog-friendly land management, surveying and mitigation for professionals has also been developed and is being delivered around the UK.
PTES also supports research into the causes of hedgehog decline. Some of this is jointly funded with BHPS.
Reserves
Briddlesford
PTES own and manage 158 hectares of land on the Isle of Wight, including a majority of the Briddlesford Copses Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC) together with about 50 hectares of farmland. The Briddlesford Copses represent the largest remaining block of ancient semi-natural woodland on the Isle of Wight. Notable species present include Hazel dormouse, Bechstein’s bat, barbastelle bat, red squirrel, narrow-leaved lungwort and the fungus weevil Pseudeuparius sepicola.
Rough Hill
Rough Hill is a traditionally managed orchard of ~4 hectares, located on a bank of the river Avon on the outskirts of Pershore, Worcestershire. Since being acquired by the Trust in 2003, the orchard is being sensitively restored for the benefit of its biodiversity and heritage value. The principal management activities are the provision and care of new fruit trees, restoration pruning of extant mature trees, and the use of extensive livestock grazing to manage the species-rich calcareous grassland communities present.
Associate organisations
PTES is a member of the IUCN and Wildlife and Countryside Link. PTES is also one of the original organisations in the State of Nature partnership.
References
Animal charities based in the United Kingdom
Biology organisations based in the United Kingdom
Charities based in London
Nature conservation organisations based in the United Kingdom
Endangered species
Environmental organisations based in England
1977 establishments in England | People's Trust for Endangered Species | [
"Biology"
] | 1,791 | [
"Biota by conservation status",
"Endangered species"
] |
39,994,387 | https://en.wikipedia.org/wiki/Limnoforming | Limnoforming (from Greek: , "lake"; Latin: , "to shape", as in shaping, fashioning, molding, modeling) is the process of manipulating the physical or chemical properties of a body of water by introducing organisms which facilitate higher level biological activity, thus impacting the overall ecology of a given body of water, and eventually adjacent ecosystems.
Limnoforming is a process using living organisms to enhance a habitat's abiotic component, ultimately rendering it more conducive to a higher ecological quality. This could be accomplished by introducing a population of organisms, e.g., invertebrates or microbes, en masse to the substrate of a body of water. These organisms would then physically and/or chemically alter the underwater environment to furnish a more suitable substrate for a wider range of biological activity; the result being an increased ecological function (e.g., in trophic dynamics), and thus a higher quality ecological state. Ultimately, limnoforming aims to accelerate the rate of ecological succession in distressed aquatic systems (e.g., lower Green Bay, Lake Michigan), so as to produce a biologically complex climax community in a comparatively short amount of time.
The concept of limnoforming originated from the benthic ecology laboratory of Dr. Jerry L. Kaster, School of Freshwater Sciences, University of Wisconsin – Milwaukee. Limnoforming was partially inspired by, and is similar in several aspects to, the concept of terraforming. The two concepts' main similarity is that both aim to accelerate the rate of change occurring in a given environment, in terms of its habitability for a given species or for a number of species, and furthermore, the overall function of its ecology. Instead of creating a habitable ecosystem or biosphere from scratch, limnoforming simply aims to amend degraded earthly aqueous environments less apt to harboring a high quality ecological community into an environment which does support an ecologically flourishing system. Limnoforming differs from traditional habitat rehabilitation or restoration in that limnoforming is driven by an early sere biological succession process that modifies the physical substrate making it better suited for later seres, whereas rehabilitation/restoration is generally driven by targeting a terminal sere that is poorly adapted at re-forming habitat upon which it depends.
The initial limnoforming study, in Green Bay, Lake Michigan, uses freshwater oligochaetes to re-consolidate highly fluid gyttja substrate (organic black ooze) found extensively in lower Green Bay. The goal is to modify substrate suitability for the mayfly Hexagenia. Historically, this mayfly was found in abundance but the eutrophication of the bay led to their demise in first half of the 20th century.
References
Aquatic ecology
Limnology | Limnoforming | [
"Biology"
] | 577 | [
"Aquatic ecology",
"Ecosystems"
] |
39,995,985 | https://en.wikipedia.org/wiki/ADS%209731 | ADS 9731 is a star system that consists of six stars, located in the constellation of Corona Borealis. Four of the stars are visually separate in the sky, forming a visual star system, which was resolved using adaptive optics in 1995. Two of these stars were themselves found to be spectroscopic binaries in 1998, resulting in a total of six known stars in the system. It is one of very few multiple star systems known to have at least six members.
Hierarchy of orbits
The components are organised thus: Aa and Ab are yellow-white main sequence stars of spectral types F4V and F5V and 1.35 and 1.32 solar masses respectively, which orbit each other every 3.27 days. This pair is in a 450-year orbit with star B, a star of spectral type G4V that has around the same mass as the Sun. Star C is a yellow white star of spectral type F3V around 1.41 times as massive as the sun, which has just started brightening and moving off the main sequence. It is in a 1000-year orbit with a pair of stars, Da and Db, a yellow-white main sequence star of spectral type F7V and a red dwarf of spectral type M3V. Da and Db take 14.28-days to orbit each other. Finally the system of stars C and Dab, and the system of stars Aab and B, take over 20,000 years to orbit each other.
The combined light from the whole system results in an integrated V magnitude of 6.9. Published apparent magnitudes for the components vary greatly and some are certainly in error, but components A, B, C, and D are approximately of visual magnitude 8, 10, 9, and 9 respectively. Models of all six components show that Aa and Ab have magnitudes 8.5 and 8.7 respectively while the faint secondary to component D is about 16th magnitude. The CD pair is slightly brighter than the AB pair, although component A is slightly brighter than component C.
Gaia EDR3 catalogues parallaxes for the four resolved stars, all at a distance of with a statistical margin of error of less than a parsec.
The star system has been considered as a possible target for direct imaging searches for exoplanets, but no planets have yet been detected in the system.
References
F-type main-sequence stars
G-type main-sequence stars
M-type main-sequence stars
6
Corona Borealis
Durchmusterung objects
139691
076563 | ADS 9731 | [
"Astronomy"
] | 520 | [
"Corona Borealis",
"Constellations"
] |
39,996,020 | https://en.wikipedia.org/wiki/AZ%20Cancri | AZ Cancri (AZ Cnc) is a M-type flare star in the constellation Cancer. It has an apparent visual magnitude of approximately 17.59.
Observations
AZ Cancri is a member of the Beehive Cluster, also known as Praesepe or NGC 2632. The spectral type of AZ Cnc is M6e, specifically M6.5Ve, and was catalogued as a flare star by Haro and Chavira in 1964 (called by them T4). AZ Cnc has also been found to be an x-ray source, with the ROSAT designations of RX J0840.4+1824 and 1RXS J084029.9+182417. The X-ray luminosity has been found to be 27.40 ergs/s
Physical characteristics
The absolute magnitude of the star has been found to be 16.9, and thus its luminosity is approximately 3.020 x 1030 ergs/s.
AZ Cancri is located approximately from the Sun, and is considered a very low-mass star with a radial velocity of 64.2±0.6 km/s. AZ Cancri belongs kinematically to the old disk. It is rotating at approximately 7.9±2.8 km/s.
Flaring
The X-ray luminosity of AZ Cnc increased by at least two orders of magnitude during a flare that lasted more than 3 hours and reached a peak emission level of more than 1029 ergs/s. During another long duration flare (March 14, 2002) on AZ Cnc, very strong wing asymmetries occurred in all lines of the Balmer series and all strong He I lines, but not in the metal lines.
The flaring atmosphere of AZ Cancri has been analysed with a stellar atmosphere model, and was found to consist of
an underlying photosphere,
a linear temperature rise vs. log column mass in the chromosphere, and
transition region (TR) with different gradients.
For the underlying photosphere, the effective temperature was found to be 2800 K, and a solar chemical composition was used. The last spectrum taken in the series after the flare was used for the quiescent chromosphere.
The line asymmetries have been attributed to downward moving material, specifically a series of flare-triggered downward moving chromospheric condensations, or chromospheric downward condensations (CDC)s as on the Sun.
Theory of coronal heating
The electrodynamic coupling theory of coronal heating developed in a solar context, has been applied to stellar corona. A distinctive feature is the occurrence of a resonance between the convective turnover time and the crossing time for Alfvén waves in a coronal loop. The resonance attains a maximum among the early M dwarf spectral types and declines thereafter. A turnover in coronal heating efficiency, presumably manifested by a decrease in Lx/Lbol, becomes evident toward the late M spectral types when the theory is applicable. This is consistent with an apparent lack of X-ray emission among the late M dwarfs. Coronal heating efficiencies do not decrease toward the presumably totally convective stars near the end of the main sequence. For "saturated" M dwarfs, 0.1% of all energy is typically radiated in X-rays, while for AZ Cnc this number increases during flaring to 7%. So far there is no evidence to suggest that AZ Cnc is less efficient than more massive dwarfs in creating a corona. The saturation boundary in X-ray luminosity extends to late M dwarfs, with Lx/Lbol ~ 10−3 for saturated dwarfs outside flaring. No coronal dividing line exists in the Hertzsprung–Russell diagram at the low-mass end of the main sequence.
AZ Cnc casts doubt on the applicability of electrodynamic coupling as there is no evidence for a sharp drop in Lx/Lbol when compared with other late M stars at least until subtype M8.
Dynamo
AZ Cnc has a corona and this may indicate that a distributive dynamo is just as efficient in producing magnetic flux as a shell dynamo. Between the generation of a magnetic field and the emission of X-rays lies the coronal heating mechanism.
References
Astronomical X-ray sources
Cancer (constellation)
Flare stars
M-type main-sequence stars
Cancri, AZ
TIC objects | AZ Cancri | [
"Astronomy"
] | 923 | [
"Cancer (constellation)",
"Astronomical X-ray sources",
"Astronomical objects",
"Constellations"
] |
39,996,154 | https://en.wikipedia.org/wiki/International%20Network%20Services%20Inc. | International Network Services Inc. (INS) was a network architecture services provider based in Mountain View, California. Previously closely associated with Cisco, it was acquired by the former Lucent in 1999 for $3.7bn. Following the collapse of the dot-com bubble, Lucent sold the unit back to employees and investors for an undisclosed sum. Then in 2007, INS was acquired by BT Group for £133 MM (now part of BT Advise Professional Services of BT (global services) based out of the US.
References
BT Group
Companies based in Mountain View, California
Network architecture | International Network Services Inc. | [
"Engineering"
] | 117 | [
"Network architecture",
"Computer networks engineering"
] |
39,996,190 | https://en.wikipedia.org/wiki/Aluminium%20acetylacetonate | Aluminium acetylacetonate, also referred to as Al(acac)3, is a coordination complex with formula Al(C5H7O2)3. This aluminium complex with three acetylacetone ligands is used in research on Al-containing materials. The molecule has D3 symmetry, being isomorphous with other octahedral tris(acetylacetonate)s.
Uses
Aluminium acetylacetonate can be used as the precursor to crystalline aluminium oxide films using low-pressure metal organic chemical vapour deposition. In horticulture it can also be used as a molluscicide.
References
Aluminium compounds
Acetylacetonate complexes | Aluminium acetylacetonate | [
"Chemistry"
] | 142 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
57,593,702 | https://en.wikipedia.org/wiki/Swinholide | Swinholides are dimeric 42 carbon-ring polyketides that exhibit a 2-fold axis of symmetry. Found mostly in the marine sponge Theonella, swinholides encompass cytotoxic and antifungal activities via disruption of the actin skeleton. Swinholides were first described in 1985 and the structure and stereochemistry were updated in 1989 and 1990, respectively. Thirteen swinholides have been described in the literature, including close structural compounds such as misakinolides/bistheonellides, ankaraholides, and hurgholide A It is suspected that symbiotic microbes that inhabit the sponges rather than the sponges themselves produce swinholides since the highest concentration of swinholides are found in the unicellular bacterial fraction of sponges and not in the sponge fraction or cyanobacteria fraction that also inhabit the sponges.
From a marine field sample containing the cyanobacterium Symploca sp, Swinholide A has also been reported in literature. The structural analogs of swinholides, ankaraholides, were also found from the cyanobacterium Geitlerinema sp. in the same experimental study. Since sponges host a range of bacteria, including symbiotic cyanobacteria, it is often wondered how swinholides are produced. A study of the production of misakinolide revealed that it was attributed to the Theonella symbiont bacterium Candidatus Entotheonella via the discovery of a trans-AT polyketides synthase (PKS) biosynthesis gene cluster. This demonstrates that the true origin of swinholides is symbiotic bacteria that inhabit sponges.
History
Cyanobacteria are known to have a wide application scope due to their structurally varied secondary metabolites they produce. Among many of the secondary metabolites, polyketides have demonstrated vital bioactivities that can be applied to a number of fields. For example, many antifungal, antitumor, and antibiotic polyketides are found from plants, bacteria, and fungi. The synthesis of polyketides is well known: small monomeric compounds frame polyketides via elongation on multidomain PKS complexes. The PKSs can add either a malonyl, acyl, or derivative unit to the chain and they are classified into types 1-3, which are dependent on factors such as functionality and domain architecture. Type I PKSs include cis- and trans-acyltransferase (trans-AT) PKSs where each section of the cis-AT PKSs encodes a dedicated AT domain and the trans-AT PKSs have distinct ATs that are used in place of the cis-encoded AT domains.
Structure
The structures of swinholide, misakinolide, and luminaolide are shown below. (Figure 1 and Figure 2).
Biosynthesis
The swinholide biosynthesis gene cluster (swi) was located on a single scaffold by BLASTp searches against misakinolide biosynthesis cluster genes. This was chosen because of the close structural resemblance of these compounds.
The swinholide biosynthesis gene cluster (85-kb) encodes for five PKS proteins, including SwiC to SwiG. This includes an AT enzyme, SwiG, which is a characteristic of trans-PKSs (Figure 3).
The swinholide biosynthesis gene cluster codes for a trans-AT PKS and does not integrate AT domains similar to the phormidolide (phm), miskinolide (mis), tolytoxin (tto), luminaolide (lum), and nosperin (nsp) gene clusters. The swinholide biosynthesis gene cluster is also similar to the tto and lum gene clusters. The swi and mis clusters both include four large genes encoding PKS enzymes and a gene encoding for the AT protein, but the order of the genes differs (Figure 4).
In the swi biosynthesis gene cluster, first gene, SwiC, is on the reverse strand and the other four genes are facing the forward direction. In the mis biosynthesis gene cluster, all genes are oriented in the same direction. Although this is different, both swi and mis biosynthesis gene clusters are composed of similar catalytic domains.
One distinct characteristic of the swi biosynthesis enzymes are its domain order, nonelongating domains, and split modules. These are common features found in trans-PKSs. There are four nonelongating ketosynthases in the swi cluster that are not a factor of the polyketide chain synthesis. Three ketosynthases function to bind with modification enzymes and the fourth ketosynthase is found in the terminal section of SwiF. There are only minor differences between swi and mis: two acyl carrier proteins (ACPs) in the middle of the SwiC protein, instead of a single ACP in the found in the MisC protein (Figure 4).
In their monomeric structures, swi and mis have two varying ring structures. In SwiF, the second and third dehydrotases (DHs) are located side-by-side (Figure 4). For mis, the same DH-like domains were identified, but the third DH is pyran synthase (PS), which creates the dihydropyran ring in the structure of mis. Further investigation revealed third DH in swi was a PS (Figure 3 and 5). The other ring formation in mis was hypothesized to be catalyzed by either accessory enzymes or DH in MisC. MisC and SwiC code for similar, but different DHs, but lack an overall PS domain in the dihydropyran ring formation. The DH domains from MisC and SwiC were found to lack the glycine in a specific motif. This, therefore, could indicate that a varying DH domain plays a vital role in ring formation.
Despite the structural differences between swi and mis, the sequence identities of the genes differed from 73 to 85% even though there are structural similarities. Scytophycin, tolytoxin, and luminaolide biosynthesis cluster genes also encompassed high sequence identity to swi and mis. Although there is high sequence identity, SwiC and MisC proteins differ from alternative gene clusters, as shown in their chemical structures (Figure 1).
Phylogenic analysis
The structural variants of the swinholide biosynthesis gene clusters origins were elucidate through phylogenic studies. A phylogenetic tree of trans-encoded AT proteins showed that all six biosynthesis gene clusters were similar and assembled their own group. Scytophycin, luminaolide, and tolytoxin biosynthesis gene clusters were arranged together based on ketosynthase domains, and the misakinolide and swinholide biosynthesis gene clusters constituted their own category (Figure 5).
References
Polyketides | Swinholide | [
"Chemistry"
] | 1,508 | [
"Biomolecules by chemical classification",
"Natural products",
"Polyketides"
] |
57,594,241 | https://en.wikipedia.org/wiki/George%20W.%20Morey | George Washington Morey (9 January 1888, Minneapolis, Minnesota – 3 October 1965, Bethesda, Maryland) was an American geochemist, physical chemist, mineralogist, and petrologist, known for the "Morey bomb" used in hydrothermal research.
Biography
Morey studied chemistry at the University of Minnesota with a bachelor's degree in 1909 and was a member of the Geophysical Laboratory of Carnegie Institution in Washington, D.C., from 1912 until his retirement in 1953. He was acting director of the laboratory from 1952 to 1953 before Philip H. Abelson replaced him.
He focused on experimental investigations of phase equilibria and thermodynamics of silicate melts with volatile components, such as water and carbon dioxide. In both WW I and WW II, Morey, as an expert on glass, was involved in the Laboratory's optical glassmaking projects for military equipment, such as rangefinders and gunsights.
Morey received in 1926 the Hillebrand Prize by the Chemical Society of Washington, in 1948 the first Arthur L. Day Medal, and in 1959 the Howard N. Potts Medal (for high refractive index, low dispersion optical glass). He was elected a Fellow of the Geological Society of America, the British Society of Glass Technology, and the American Ceramic Society, which awards a George W. Morey Award for glass technology.
Selected publications
with Clarence Norman Fenner: The ternary system H2O-K2SiO3-SiO2, Journal of the American Chemical Society, Vol. 40, 1917, pp. 49–59
A comparison of the heating-curve and quenching methods of melting point determinations, Journal of the Washington Academy of Sciences, Volume 13, 1923, pp. 326–329
with Norman L. Bowen: The melting relations of soda-lime-silica glasses, Transactions of the Society of Glass Technology, Vol. 9, 1925, pp. 226–264
The Composition of Glass, The Scientific Monthly, Vol. 42, 1936, pp. 541–554
The Properties of Glass, American Chemical Monograph Series, Reinhold, New York, 1938.
References
American mineralogists
American geochemists
Fellows of the Geological Society of America
Howard N. Potts Medal recipients
1888 births
1965 deaths
20th-century American chemists | George W. Morey | [
"Chemistry"
] | 478 | [
"Geochemists",
"American geochemists"
] |
57,594,587 | https://en.wikipedia.org/wiki/ESSA-5 | ESSA-5 (or TOS-C) was a spin-stabilized operational meteorological satellite. Its name was derived from that of its oversight agency, the Environmental Science Services Administration (ESSA).
Launch
ESSA-5 was launched on April 20, 1967, at 11:17 UTC. It was launched atop a Delta rocket from Vandenberg Air Force Base, California, U.S.. The spacecraft had a mass of at the time of launch. ESSA-5 had an inclination of 101.9°, and an orbited the Earth once every 113.6 minutes. Its perigee was and its apogee was .
References
Spacecraft launched in 1967
Weather satellites of the United States
Television Infrared Observation Satellites | ESSA-5 | [
"Astronomy"
] | 149 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
57,594,600 | https://en.wikipedia.org/wiki/ESSA-6 | ESSA 6 (or TOS-D) was a spin-stabilized operational meteorological satellite. Its name was derived from that of its oversight agency, the Environmental Science Services Administration (ESSA).
Details
ESSA 6 had a mass of at the time of launch.
The satellite's electrical power was supplied by about 10,000 1x2 cm solar cells on the cover and 21 nickel-cadmium batteries.
Two redundant wide-angle APT (Automatic Picture Transmission) cameras, mounted on opposite sides and perpendicular to the spin axis, captured images. This subsystem was a camera-transmitter setup, designed to transmit real-time daylight images of cloud cover to ground stations. It included two 2.54-cm vidicon cameras with lenses, mounted 180° apart. Each orbit, the cameras captured four or eight images, with picture taking lasting 8 seconds and transmission 200 seconds. The 800-line images were transmitted at 137.5 MHz to local APT stations, with reticle marks on the images to assist with geographical alignment. Each picture covered a 3100 x 3100 km area with 4 km resolution at nadir, with a 30% overlap to ensure complete coverage.
The base featured crossed-dipole antennas for command reception, while a monopole antenna provided telemetry (136.500 MHz) and tracking (136.770 MHz) from the top.
Spin rate was regulated to 10.9 rpm using a Magnetic Attitude Spin Coil (MASC), which interacted with Earth's magnetic field to maintain a stable spin axis normal to the orbital plane, within ±1 degree.
Mission
ESSA 6 was launched on November 10, 1967, at 18:00 UTC, atop a Delta rocket from Vandenberg Air Force Base, California, USA.
ESSA 6 had an inclination of 102.12°, and orbited the Earth once every 114.8 minutes. Its perigee was and its apogee was .
The satellite performed normally after launch.
The APT camera system was successful, operating nearly continuously until November 4, 1969 when the spacecraft was deactivated.
References
Spacecraft launched in 1967
Weather satellites of the United States
Television Infrared Observation Satellites | ESSA-6 | [
"Astronomy"
] | 442 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
57,594,608 | https://en.wikipedia.org/wiki/Concrete%20hinge | Concrete hinges are hinges produced out of concrete, with little or no steel in the hinge neck, which allows a rotation without a significant bending moment. The high rotations result from controlled tensile cracks as well as creep. Concrete hinges are mostly used in bridge
engineering as monolithic, simple, economic alternative to steel hinges, which would need regular maintenance. Concrete hinges are also used in tunnel engineering. A concrete hinge consist of the hinge neck, which has a reduced cross section and of the hinge heads, which have a strong reinforcement.
History and guidelines
Freyssinet invented the concrete hinges.
Leonhardt introduced guidelines in the 1960s which are still used till the 2010s.
Janßen introduced the application of concrete hinges in tunnel engineering.
Gladwell developed another guideline for narrowing cross sections, which predicts a stiffer behaviour than the Leonhardt/Janßen-model
Marx and Schacht translated Leonhardts guidelines for the first time in the nowadays used semipropablistic safteyconcept.
Schlappal, Kalliauer and coworkers introduced for the first time both limit caces (service-limit-states (SLS) and ultimate-limite-states (ULS)).
Kaufmann, Markić und Bimschas did further studies on concrete hinges.
Stresses, rotational capacity, bearing capacity
Due to triaxial compression, strength in the neck region is much higher than for uniaxial compression, because lateral expansion is restricted.
Eurocode 2 suggests for typical dimensions a compressive strength equal to about twice of the unixalial compressive strength.
Also the concrete hinge neck has no, or almost no reinforcement, but the concrete hinge heads need a dense reinforcement cache, because of tensile splitting.
Literature
Fritz Leonhardt: Vorlesungen über Massivbau - Teil 2 Sonderfälle der Bemessung im Stahlbetonbau. [Concrete hinges: test report, recommendations for structural design. Critical stress states of concrete under multiaxial static short-term loading Springer-Verlag, Berlin 1986, , S. 123–132. (in German)
VPI: Der Prüfingenieur. Ausgabe April 2010, S. 15–26, (bvpi.de PDF; 2,3 MB). (in German)
References
Bridge design
hinge | Concrete hinge | [
"Engineering"
] | 484 | [
"Structural engineering",
"Bridge design",
"Architecture"
] |
57,594,622 | https://en.wikipedia.org/wiki/ESSA-7 | ESSA-7 (or TOS-E) was a spin-stabilized operational meteorological satellite. Its name was derived from that of its oversight agency, the Environmental Science Services Administration (ESSA).
Launch
ESSA-7 was launched on August 16, 1968, at 11:31 UTC. It was launched atop a Delta rocket from Vandenberg Air Force Base, California, USA. The spacecraft had a mass of at the time of launch. ESSA-7 had an inclination of 101.72°, and an orbited the Earth once every 114.9 minutes. Its perigee was and its apogee was .
References
Spacecraft launched in 1968
Weather satellites of the United States
Television Infrared Observation Satellites | ESSA-7 | [
"Astronomy"
] | 146 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
57,595,591 | https://en.wikipedia.org/wiki/Interstellar%20Mapping%20and%20Acceleration%20Probe | The Interstellar Mapping and Acceleration Probe (IMAP) is a heliophysics mission that will simultaneously investigate two important and coupled science topics in the heliosphere: the acceleration of energetic particles and interaction of the solar wind with the local interstellar medium. These science topics are coupled because particles accelerated in the inner heliosphere play crucial roles in the outer heliospheric interaction. In 2018, NASA selected a team led by David J. McComas of Princeton University to implement the mission, which is currently scheduled to launch no earlier than September 2025. IMAP will be a Sun-tracking spin-stabilized satellite in orbit about the Sun–Earth L1 Lagrange point with a science payload of ten instruments. IMAP will also continuously broadcast real-time in-situ data that can be used for space weather prediction.
It is the fifth mission selected in the Solar Terrestrial Probes program, after TIMED, Hinode, STEREO and MMS.
Science
Acceleration of charged particles up to high energy is ubiquitous throughout the universe, occurring at stars, magnetospheres, black holes, neutron stars, supernova remnants, and other locations. The precise processes behind this acceleration are not well understood. There are intermediate suprathermal particles which have energies between the energetic particles and the bulk thermal plasma. Understanding how these particles are energized and form the seed population of the energetic particles is one of the science topics that IMAP will investigate.
The solar wind and its associated magnetic field have blown a bubble in interstellar space called the heliosphere. IMAP will study the heliosphere boundary where the solar wind collides with material from the rest of the galaxy. Using Energetic Neutral Atoms (ENAs), IMAP will image this interaction region from the inner Solar System. In addition, IMAP will also directly measure the neutral particles of the interstellar medium, because they flow through the heliosphere relatively unmodified.
IMAP's science goals are based on the four science objectives specified in the IMAP Announcement of Opportunity (from the outside in):
Improve understanding of the composition and properties of the local interstellar medium (LISM).
Advance understanding of the temporal and spatial evolution of the boundary region in which the solar wind and the interstellar medium interact.
Identify and advance the understanding of processes related to the interactions of the magnetic field of the Sun and the LISM.
Identify and advance understanding of particle injection and acceleration processes near the Sun, in the heliosphere and heliosheath.
Mission
Profile
After launch, the spacecraft will take several months to transit to about away from Earth towards the Sun at what is called the first Lagrange point (L1). The spacecraft will then use on-board propulsion to insert into an approximately 10° x 5° Lissajous orbit around L1, very similar to the orbit of Advanced Composition Explorer (ACE). The baseline mission is 3 years, but all expendables are designed for a lifetime of more than 5 years.
Spacecraft
IMAP is a simple spin-stabilized (~4 RPM) spacecraft with ten instruments. Daily attitude maneuvers will be used to keep the spin axis and top deck (with solar arrays) pointed in the direction of the incoming solar wind, which is a few degrees away from the Sun. In the L1 Lissajous orbit, the rear deck, with its communication antenna, approximately points at the Earth.
Instruments
The ten instruments on IMAP can be grouped into three categories: 1) Energetic neutral atom detectors (IMAP-Lo, IMAP-Hi, and IMAP-Ultra); 2) Charged particle detectors (SWAPI, SWE, CoDICE, and HIT); and 3) Other coordinated measurements (MAG, IDEX, GLOWS).
Shown here (top panel) are oxygen fluences measured at 1 AU by several instruments onboard Advanced Composition Explorer (ACE) during a 3-year period, with representative particle spectra obtained for gradual and impulsive Solar Energetic Particles (SEPs), corotating interaction regions (CIRs), Anomalous Cosmic Rays (ACRs), and Galactic Cosmic Rays (GCRs), and (top panel inset) ion fluxes in the Voyager 1 direction using in situ observations from Voyager and remote ENA observations from Cassini–Huygens and Interstellar Boundary Explorer (IBEX). (Middle panel) SWAPI, CoDICE, and HIT provide comprehensive composition, energy, and angular distributions for all major solar wind species (core and halo), interstellar and inner source pick-up ions, suprathermal, energetic, and accelerated ions from SEPs, interplanetary shocks, as well as ACRs. SWE, CoDICE and HIT also provide energy and angular distributions of the solar wind ion and electron core, halo, strahl, as well as energetic and relativistic electrons up to 1 MeV.
IMAP-Lo
IMAP-Lo is a single-pixel neutral atom imager that gives energy and angle-resolved measurements of ISN atoms (H, He, O, Ne, and D) tracked over >180° in ecliptic longitude and energy resolved global maps of ENA H and O. IMAP-Lo has heritage from the IBEX-Lo on IBEX but provides much larger collection power.
IMAP-Hi
IMAP-Hi consists of two identical, single-pixel high energy ENA Imagers that measure H, He, and heavier ENAs from the outer heliosphere. Each IMAP-Hi Imager is very similar in design to the IBEX-Hi ENA Imager but incorporate key modifications that enable substantially improved resolution, spectral range, and collection power. The instrument also incorporates a time-of-flight (TOF) system for identification of ENA species.
IMAP-Ultra
The IMAP-Ultra instrument images the emission of ENAs produced in the heliosheath and beyond, primarily in H atoms between ~3 and 300 keV, but it is also sensitive to contributions from He and O. Ultra is nearly identical to the Jupiter Energetic Neutral Imager (JENI), in development for flight on the European Space Agency's Jupiter Icy Moon Explorer (JUICE) mission to Jupiter and Ganymede. Ultra's primary differences from JENI are the use of two identical copies, one mounted perpendicular to the IMAP spin axis (Ultra90) and one mounted at 45° from the anti-sunward spin axis (Ultra45) for better sky coverage, and the use of slightly thicker, UV-filtering foils covering the back plane MCPs to reduce backgrounds associated with interstellar Lyman-α photons.
Solar Wind and Pick-up Ion (SWAPI)
The Solar Wind and Pickup Ion (SWAPI) instrument measures solar wind H+ and He++ and interstellar He+ and H+ pick-up ions (PUIs). SWAPI is nearly identical to the New Horizons Solar Wind Around Pluto (SWAP) instrument. SWAPI is a simplification of SWAP, and by removal of SWAP's retarding potential analyzer, significantly increases transmission and improves sensitivity, further enhancing PUI observations.
Solar Wind Electron (SWE)
The Solar Wind Electron (SWE) instrument measures the 3D distribution of solar wind thermal and suprathermal electrons from 1 eV to 5 keV. SWE is based on the heritage Ulysses / SWOOPS, ACE/SWEPAM and Genesis/GEM instruments, with updated electronics based on Van Allen Probes/HOPE. SWE is optimized to measure in situ solar wind electrons at L1 to provide context for the ENA measurements and perform the in situ solar wind observations necessary to understand the local structures that can affect acceleration and transport.
Compact Dual Ion Composition Experiment (CoDICE)
The Compact Dual Ion Composition Experiment (CoDICE) measures charged particles in two separate energy ranges in a compact, combined instrument. CoDICELo is an electrostatic analyzer with a time-of-flight versus energy (TOF/E) subsystem to measure the 3D velocity distribution functions (VDFs) and ionic charge state and mass composition of ~0.5–80 keV/q ions. CoDICEHi uses the common TOF/E subsystem to measure the mass composition and arrival direction of ~0.03–5 MeV/nuc ions and ~20–600 keV electrons.
High-energy Ion Telescope (HIT)
The High-energy Ion Telescope (HIT) uses silicon solid-state detectors to measure the elemental composition, energy spectra, angular distributions, and arrival times of H to Ni ions over a species-dependent energy range from ~2 to ~40 MeV/nuc. HIT, heavily based on the Low Energy Telescope (LET) on the Solar Terrestrial Relations Observatory (STEREO), delivers full-sky coverage with a large geometry factor. A portion of the HIT viewing area is also optimized to measure 0.5 - 1.0 MeV electrons.
Magnetometer (MAG)
The IMAP magnetometer (MAG) consists of a pair of identical triaxial fluxgate magnetometers that measure the 3D interplanetary magnetic field. Both magnetometers are mounted on a 1.8 m boom, one on the end and the other in an intermediate position. This configuration, through gradiometry, reduces the effect of spacecraft magnetic fields on the measurements of the instrument by dynamically removing the spacecraft field. The MAG sensors are based on the Solar Orbiter mission magnetometers and are built by Imperial College London.
Interstellar Dust Experiment (IDEX)
The Interstellar Dust Experiment (IDEX) is a high-resolution dust analyzer that provides the elemental composition, speed and mass distributions of interstellar dust particles. IDEX's sensor head has a large effective target area (), which allows it to collect a statistically significant number of dust impacts (> 100/year). This instrument was constructed at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder.
GLObal solar Wind Structure (GLOWS)
The GLObal Solar Wind Structure (GLOWS) is a non-imaging single-pixel Lyman-α photometer that will be used to observe the sky distribution of the helioglow to better understand the evolution of the solar wind structure. The helioglow is formed by the interaction between interstellar neutral hydrogen (ISN H) and solar photons in a specific ultraviolet region called the Lyman-α waveband.
Photons enter the detector through a collimator with a baffle that restricts the photons to those only from GLOWS’ field of view (FOV). A spectral filter allows only photons found in the Lyman-α wavelength band into a channel electron multiplier (CEM) detector that counts them. GLOWS’ FOV shifts with IMAP's daily spin axis redirection, allowing for sequential observations of the structure of the solar wind from separate locations around the Sun. The Lyman-α photon counts from these observations can be used to build a more comprehensive picture of the solar wind structure and how it changes through the solar cycles.
GLOWS design and assembly is led by the Space Research Center, Polish Academy of Sciences, Warsaw, Poland (CBK PAN).
Communications
Nominally, IMAP will have two 4-hour contacts per week through the NASA Deep Space Network (DSN). This is sufficient to upload any commands, download the week's worth of science data and housekeeping, and perform spacecraft ranging required for navigation. DSN will communicate with the IMAP Mission Operation Center (MOC) at Johns Hopkins University Applied Physics Laboratory, which will operate the spacecraft. All science and ancillary data will pass through the MOC to the Science Operations Center (SOC) at LASP. The IMAP SOC at LASP will be responsible for all aspects of instrument operations: planning, commanding, health and status monitoring, anomaly response, and sustaining engineering for the instruments. The SOC will also handle science data processing (including data calibration, validation and preliminary analysis), distribution, archiving, and maintaining the IMAP data management plan. Science data will be produced centrally using algorithms, software, and calibration data provided and managed by each instrument team.
All science and other data will be shared with the heliophysics community as rapidly as practical with an open data policy compliant with the NASA Heliophysics Science Data Management Policy. The NASA Space Physics Data Facility (SPDF) is the final archive for IMAP, with regular transfer of data to the SPDF so that the data can be made available through their Coordinated Data Analysis Web (CDAWeb) site.
Space weather data
IMAP will supply critical real-time space weather data through its "IMAP Active Link for Real-Time" or I-ALiRT. IMAP will continuously broadcast a small subset (500 bit/s) of the science data for I-ALiRT to supporting ground stations around the world when not in contact with the DSN. During DSN tracks, the flight system includes the space weather data in the full-rate science data stream, which the MOC receives from the DSN and forwards to the SOC. In either case, the SOC processes these real-time observations to create the data products required by the space weather community. Data include all of the important parameters currently provided by Advanced Composition Explorer (ACE), but at significantly higher cadence, and also include several new key parameters.
Management
This is the fifth mission in NASA's Solar Terrestrial Probes program. The Heliophysics Program Office at NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the STP program for the agency's Heliophysics Science Division in Washington, D.C.
The mission's principal investigator is David J. McComas of Princeton University. The Johns Hopkins University's Applied Physics Laboratory in Laurel, Maryland, will provide project management.
The mission is cost-capped at US$564 million, excluding cost for the launch on a SpaceX Falcon 9 launch vehicle from Cape Canaveral Space Launch Complex 40 (SLC-40) at Cape Canaveral Space Force Station (CCSFS) in Florida. As of April 2020, the preliminary total cost of the mission is estimated to be US$707.7 million to US$776.3 million.
Missions of Opportunity
NASA plans on including an EELV Secondary Payload Adapter (ESPA) (Evolved expendable launch vehicle) Grande ring below the IMAP spacecraft, which will give the opportunity for 4 or 5 secondary payloads to ride along with the IMAP launch. Deployment of the secondary payloads will occur after IMAP deployment into a transfer orbit to the Earth-Sun L1 Lagrange point. Some of the slots may be used by other divisions in the Science Mission Directorate and some may be used by other government agencies. Two opportunities for slots were competed for the Heliophysics Science Division as part of the Third Stand Alone Missions of Opportunity Notice (SALMON-3) Program Element Appendix (PEA), with proposals for both due on 30 November 2018. Selection for Phase A studies should be announced in 2019.
Science opportunity
The Announcement of Opportunity for the 2018 Heliophysics Science Missions of Opportunity (MoO) included the option of proposing a Small Complete Mission (SCM) to utilize the IMAP ESPA Grande to launch a secondary payload. Up to two ports on the ESPA Grande ring may be allocated for Science MoOs. The payloads are designated as Class D as defined in NPR 8705.4.
TechDemo opportunity
The Announcement of Opportunity for the 2018 Heliophysics Technology Demonstration (TechDemo) Missions of Opportunity requested SCM proposals for spaceflight demonstration of innovative medium Technology Readiness Level (TRL) technologies that enable significant advances in NASA's Heliophysics Science Objectives and Goals. TechDemo investigations must be proposed for flight as a secondary payload with the IMAP mission. Up to two ports on the ESPA Grande ring may be allocated for TechDemo. The payloads are designated as Class D as defined in NPR 8705.4. Down-selection is targeted for the third quarter FY 2020.
See also
Interstellar Boundary Explorer - The IBEX spacecraft, launched in October 2008
Advanced Composition Explorer - The ACE spacecraft, launched in August 1997
Voyager 1 - The Voyager 1 spacecraft, launched in September 1977
Heliophysics Science Division - NASA science division in the Science Mission Directorate
References
External links
- Official Princeton IMAP site
ACE Home - Official Caltech ACE site
IMAP Quick Facts - University of Colorado, Boulder IMAP page
Heliophysics - Official NASA Heliophysics webpage
NASA space probes
Solar space observatories
2025 in spaceflight | Interstellar Mapping and Acceleration Probe | [
"Astronomy"
] | 3,432 | [
"Space telescopes",
"Solar space observatories"
] |
57,595,999 | https://en.wikipedia.org/wiki/Great%20Marsh | The Great Marsh (also sometimes called the Great Salt Marsh) is a long, continuous saltmarsh in eastern New England extending from Cape Ann in northeastern Massachusetts to the southeastern coast of New Hampshire. It includes roughly 20,000–30,000 acres of saltwater marsh, mudflats, islands, sandy beaches, dunes, rivers, and other water bodies. The Great Marsh comprises much of the northeastern half of Essex County, Massachusetts, and touches the towns and cities of Gloucester, Essex, Ipswich, Rowley, Newbury, Newburyport, and Salisbury in Massachusetts as well as the towns of Seabrook and Hampton in New Hampshire. It is a designated Important Bird Area.
References
Salt marshes
Newbury, Massachusetts
Rowley, Massachusetts
Ipswich, Massachusetts
Wetlands of Massachusetts | Great Marsh | [
"Chemistry"
] | 153 | [
"Salt marshes",
"Salts"
] |
57,596,299 | https://en.wikipedia.org/wiki/Methionine%20sulfoximine | Methionine sulfoximine (MSO, also known as MetSox) is an irreversible glutamine synthetase inhibitor. It is the sulfoximine derivative of methionine with convulsant effects.
Methionine sulfoximine is composed of two different diastereomers, which are L-S-Methionine sulfoximine and L-R-Methionine sulfoximine. These affect the longevity of the model mouse for Lou Gehrig's disease. Overproduction of glutamate results to excitotoxicity, which kills the cell. Since methionine sulfoximine inhibits glutamate production in the brain, it prevents excitotoxicity. Thus, increasing the longevity of the mice.
Mechanism of action
MSO is phosphorylated by glutamine synthetase. The resulting product acts as a transition state analog that is unable to diffuse from the active site, thereby inhibiting the enzyme.
References
Convulsants
Glutamine synthetase inhibitors
Alpha-Amino acids
Amino acid derivatives
Sulfoximines | Methionine sulfoximine | [
"Chemistry"
] | 246 | [
"Functional groups",
"Sulfoximines"
] |
57,596,406 | https://en.wikipedia.org/wiki/Contact-dependent%20growth%20inhibition | Contact-dependent growth inhibition (CDI) is a phenomenon where a bacterial cell may deliver a polymorphic toxin molecule into neighbouring bacterial cells upon direct cell-cell contact, causing growth arrest or cell death.
Discovery
CDI is now a blanket term to describe interbacterial competition that relies on direct cell-cell contact in bacteria. However, the phenomenon was first discovered in 2005 in the isolate EC93 of Escherichia coli found in rat intestine, and, in this case, was mediated by a Type V secretion system. This isolate dominated the rat's gut flora and appeared to be particularly good at outcompeting lab strains of E. coli when grown in co-culture. The novel part of this discovery was the fact that the inhibitory effects of the isolated E. coli appeared to require direct cell-cell contact. Before CDI was discovered in this isolate, the only systems known to mediate direct interbacterial competition by intoxication were toxins secreted into the extracellular space. Thus, these did not require cell-cell contact. A second system that could mediate CDI was discovered in 2006 in the pathogenic bacterium Vibrio cholerae, the cause of the gastro-intestinal disease cholera, and the opportunistic pathogen Pseudomonas aerugenosa. This system was much different that the Type V secretion system identified in E. coli, and thus formed a new class of CDI: the Type VI Secretion System.
Types of CDI
Type IV
The Type IV Secretion System T4SS is found in many species of Gram-negative and Gram-positive bacteria as well as in archea and are typically associated with conjugation or delivery of virulence proteins to eukaryotic cells. Some species of plant pathogen Xanthomonas, however, possess a particular T4SS capable of mediating CDI by delivering a peptidoglycan hydrolase. This effector kills targets that do not have the cognate immunity protein similar to other CDI systems.
Type V
The first CDI system to be discovered was a Type V secretion system, encoded by the cdiBAI gene cluster found widespread throughout pathogenic Gram-negative bacteria. The first protein encoded in the operon, CdiB, is an outer membrane beta-barrel protein that exports CdiA, presenting it on the cell surface of a CDI-expressing (CDI+) bacterium. CdiA is predicted to form a filament several nanometers long that extends outward from the CDI+ cell in order to interact with neighbouring bacteria via outer membrane protein receptors to which it will bind. The C-terminal 200-300 amino acids of CdiA harbours a highly variable toxic domain (CdiA-CT), which is delivered into a neighbouring bacterium upon receptor recognition, enabling the CDI+ cell to arrest the growth of the cell into which it delivers this CdiA-CT toxin. This toxic domain is linked to the rest of CdiA via a VENN peptide motif and vary significantly more between species than does the rest of CdiA. CdiI is an immunity protein to prevent auto-inhibition by the C-terminal toxin. This also prevents the bacteria from killing or inhibiting the growth of their siblings as long as these possess the immunity gene. Many CDI systems contain additional pairs called "orphans" following the first copy and these orphans can be connected to different main CdiA:s in a modular fashion.
Type VI
The Type VI Secretion System T6SS is widely spread amongst Gram-negative bacteria and consists of a protein complex with 13 core components (TssA to TssM), forming a needle-like structure capable of injecting effector molecules into neighbouring target cells similar to the contractile tail of the T4 bacteriophage. The T6SS is capable of delivering effectors to both prokaryote and eukaryotes target cells. Upon contraction of the T6SS, effectors are transported across the cytosol of the bacteria cell into the target cells. Effectors are loaded onto this dynamic secretion system through interactions with Hcp, VgrG and PAAR-domains. The full list of T6SS effectors is not known.
Rhs toxins
The Rearrangement hotspot system (Rhs) exists in both Gram-negative and Gram-positive bacteria. Similar to CdiA, these systems consists of big proteins with a conserved N-terminal domain and a variable C-terminal toxin domain requiring a cognate immunity protein. Many Rhs systems contain PAAR-domains (Proline-Alanine-Alanine-Arginine) which can interact with the VgrG of the T6SS apparatus making it required for Rhs secretion. The name Rearrangement hotspots comes from the discovery when the system was first identified as elements on the E. coli chromosome that were continuously rearranging. The Gram-positive soil bacterium Bacillus subtilis possesses an Rhs homolog called Wall-associated protein A (WapA) capable of mediating CDI whilst requiring a cognate immunity protein, WapI, to prevent auto-inhibition.
Other functions
Cell aggregation and biofilm formation
In E. coli, CdiA molecules may interact with those found on neighboring cells, independent of the receptor to which CdiA binds. In addition with receptor binding, these homotypic interactions cause cell-cell aggregation and promote biofilm formation for CDI+ bacteria. In a similar fashion, the CdiA homolog BcpA in Burkholderia thailandensis causes up-regulation of genes encoding pili and polysaccharides when delivered to sibling cells which are in possession of the immunity protein BcpI. This change in gene expression leads to increased biofilm formation in the bacterial population through a phenomenon now known as Contact-Dependent Signalling. Furthermore, the T6SS in V. cholerae is active in biofilms, enabling a cell expressing T6SS to kill nearby cells which do not have the specific immunity. The release of DNA from target cell death can be beneficial for gene transfer as well as the release of extra cellular DNA into the matrix.
Antibiotic persistence
In E. coli, CdiA-CT toxins have been found to induce persister cell formation in a clonal population when delivered to cells that lack sufficient levels of CdiI immunity to neutralise the incoming toxins. The intoxication of the cells leads to an increase of cellular (p)ppGpp levels, which in turn leads to degradation of the immunity protein and eventually to a higher extend of intoxication, resulting in persister formation.
References
Microbial growth and nutrition
Microbiology terms | Contact-dependent growth inhibition | [
"Biology"
] | 1,371 | [
"Microbiology terms"
] |
57,597,771 | https://en.wikipedia.org/wiki/Network%20%28typeface%29 | Network is a sans-serif typeface originally created by Monotype for use on the transport network in the Birmingham/West Midlands metropolitan area in the United Kingdom. The typeface is based on VAG Rounded, which was previously the typeface used by the West Midlands Passenger Transport Executive for public information in the county.
Network was in use for transport branding and signage until 2018, when it was phased out by Transport for West Midlands who introduced new shared branding across different transport modes, including the West Midlands Metro, using LL Circular by Lineto as the primary typeface.
See also
Public signage typefaces
Johnston (typeface) - the iconic typeface in use by Transport for London, in a similar fashion to Network
Notes
References
Government typefaces
Corporate typefaces
Transport in the West Midlands (county)
Sans-serif typefaces
Neo-grotesque sans-serif typefaces | Network (typeface) | [
"Technology"
] | 181 | [
"Computing stubs",
"Digital typography stubs"
] |
57,598,381 | https://en.wikipedia.org/wiki/Amazon%20Elastic%20File%20System | Amazon Elastic File System (Amazon EFS) is a cloud storage service provided by Amazon Web Services (AWS) designed to provide scalable, elastic, concurrent with some restrictions, and encrypted file storage for use with both AWS cloud services and on-premises resources. Amazon EFS is built to be able to grow and shrink automatically as files are added and removed. Amazon EFS supports Network File System (NFS) versions 4.0 and 4.1 (NFSv4) protocol, and control access to files through Portable Operating System Interface (POSIX) permissions.
Use cases
According to Amazon, use cases for this file system service typically include content repositories, development environments, web server farms, home directories and big data applications.
Data consistency
Amazon EFS provides open-after-close consistency semantics that applications expect from NFS.
Availability
Amazon EFS is available in all the public AWS regions at least since December 2019.
See also
GlusterFS
Red Hat Storage Server
References
External links
Amazon Elastic File System
Amazon Web Services
Cloud infrastructure
Cloud platforms
Distributed data storage
Cloud storage
Distributed file systems | Amazon Elastic File System | [
"Technology"
] | 231 | [
"Cloud infrastructure",
"Cloud platforms",
"Computing platforms",
"IT infrastructure"
] |
57,599,237 | https://en.wikipedia.org/wiki/Hyclate | A hyclate () is a pharmaceutical term for hydrochloride hemiethanolate hemihydrate (·HCl·EtOH·H2O), e.g. doxycycline hyclate.
References
Hydrochlorides
Ethanol
Hydrates | Hyclate | [
"Chemistry"
] | 61 | [
"Hydrates"
] |
57,599,349 | https://en.wikipedia.org/wiki/Furan%20resin | Furan resin refers to polymers produced from various furan compounds, of which the most common starting materials are furfuryl alcohol and furfural. In the resin and in the cured polyfurfurol, the furan rings are not connected by conjugation. The resins are generally used as binders for sand castings. The furan monomer is typically converted to a free-flowing resin with mild acid catalysis. Curing is achieved using strong acid.
Types
The term furan resins is not used uniformly in the literature. For example, some authors refer to resins based on furfuryl alcohol and furan as furan resins, while others use the term only for resins based on furfuryl alcohol. In addition to homopolymers of the two starting materials, also copolymers comprising for example methanal, urea or phenol are counted as furan resins. Furfurylated wood is made by impregnating wood and then forming a furan resin.
Production
Furan resins based on furfuryl alcohol are produced by polycondensation under the presence of weak acids. The polycondensation leads to various linear oligomers that differ on chainlength and linking between the furan units. The linking of the furan units via methylenbridge (–CH2–) is predominating but the rings can be linked via dimethylenetherbridges (–CH2–O–CH2–) The etherbridges are unstable especially in very acidic environment. They can be converted to methylenbridges by release of formaldehyde.
To produce a storable resin, the reaction is interrupted by the addition of sodium hydroxide. The products are brownish in colour and have a low to medium viscosity. They are stable at 40 °C for approximately 6 months. In a second step, the resins can be cured to a thermoset either at room temperature by adding acids (e.g. p-toluenesulfonic acid, phosphoric acid) or at higher temperatures by adding latent curing agents such as ammonium nitrate. The reactions involved are complex and have been studied for a long time. Segments with conjugated double bonds are proposed to lead to cross-linking.
Properties
Before curing, the properties of furan resins are similar to those of other curable resins. They can be used as binders, are reactive to acids, thermally reactive and cross-linkable. Cured furan resins are resistant to attack by strong acids, bases, and halogenated hydrocarbons. They are attacked by oxidizing agents. Furan resins exhibit good thermal stability. Continuous use at 100-120 °C is routine. Some furan resins can even be used at up to 150 °C. Some grades are characterized by their low flammability and low smoke emission. They also have a high strength.
References
Organic polymers
Adhesives
Synthetic resins
Thermosetting plastics | Furan resin | [
"Chemistry"
] | 625 | [
"Organic compounds",
"Synthetic materials",
"Organic polymers",
"Synthetic resins"
] |
57,601,067 | https://en.wikipedia.org/wiki/Solar%20Terrestrial%20Probes%20program | NASA's Solar Terrestrial Probes program (STP) is a series of missions focused on studying the Sun-Earth system. It is part of NASA's Heliophysics Science Division within the Science Mission Directorate.
Objectives
Understand the fundamental physical processes of the complex space environment throughout the Solar System, which includes the flow of energy and charged material, known as plasma, as well as a dynamic system of magnetic and electric fields.
Understand how human society, technological systems, and the habitability of planets are affected by solar variability and planetary magnetic fields.
Develop the capability to predict the extreme and dynamic conditions in space in order to maximize the safety and productivity of human and robotic explorers.
Missions
TIMED
The TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) is an orbiter mission dedicated to study the dynamics of the Mesosphere and Lower Thermosphere (MLT) portion of the Earth's atmosphere. The mission was launched from Vandenberg Air Force Base in California on December 7, 2001 aboard a Delta II rocket launch vehicle.
Hinode
Hinode, an ongoing collaboration with JAXA, is a mission to explore the magnetic fields of the Sun. It was launched on the final flight of the M-V-7 rocket from Uchinoura Space Center, Japan on September 22, 2006.
STEREO
STEREO (Solar Terrestrial Relations Observatory) is a solar observation mission. It consists in two nearly identical spacecraft, launched on October 26, 2006.
MMS
The Magnetospheric Multiscale Mission (MMS) is a mission to study the Earth's magnetosphere, using four identical spacecraft flying in a tetrahedral formation. The spacecraft were launched on March 13, 2015.
IMAP
IMAP (Interstellar Mapping and Acceleration Probe) is a heliosphere observation mission. Planned for launch in 2025, it will sample, analyze, and map particles streaming to Earth from the edges of interstellar space.
References
External links
NASA Goddard Space Flight Center - Solar Terrestrial Probes Program
NASA Science Mission Directorate - Solar Terrestrial Probes Program
NASA programs
Space plasmas
Space science experiments | Solar Terrestrial Probes program | [
"Physics"
] | 429 | [
"Space plasmas",
"Astrophysics"
] |
57,603,075 | https://en.wikipedia.org/wiki/Obba%20rivulosa | Obba rivulosa is a species of crust fungus in the family Gelatoporiaceae. It is found in the Caribbean, Europe, North America, and South America. Its genome sequence was reported in 2016.
References
Fungi described in 1869
Fungi of Europe
Fungi of North America
Fungi of South America
Fungi of the Caribbean
Gelatoporiaceae
Taxa named by Miles Joseph Berkeley
Fungus species | Obba rivulosa | [
"Biology"
] | 78 | [
"Fungi",
"Fungus species"
] |
57,610,018 | https://en.wikipedia.org/wiki/Tanniemola%20Liverpool | Tanniemola Liverpool (born 20 April 1971) is a Professor of Theoretical Physics at the University of Bristol.
Early life and education
Liverpool was born in London to parents from Sierra Leone. His father, Lennox Liverpool, also has a PhD in Mathematics and taught at the University of Jos. He went to school at the Liverpool Blue Coat School. He studied physics at Trinity Hall, Cambridge, graduating in 1991. He completed his doctoral studies, "A Stochastic Approach to Describing Geological Systems" at the University of Cambridge under the supervision of Sam Edwards in 1995. Whilst at Cambridge he was part of a Group to Encourage Ethnic Minority Applicants.
Research and career
Liverpool studies the role of hydrodynamic interactions in the collective behaviour of particles in a fluid. He observed that swimming bacteria, algae and spermatozoa could be described as "living liquid crystals". By understanding the movement of artificial 'swimmers' in soft matter, he hopes to design new cancer treatments.
After his PhD, Liverpool joined University of Cologne as a postdoctoral researcher. Liverpool was awarded a Royal Society Research Fellowship in 2000. He joined the University of Leeds, working in the Applied Mathematics group.
Liverpool works at the University of Bristol in the Centre for Synthetic Biology. He studies the self-assembly of protein building blocks. He is on the editorial board of the Journal of Theoretical Biology. He is the chair of the Institute of Physics Liquid and Complex Physics group.
He is part of several initiatives to improve diversity within the physics and mathematics communities. He was selected as one of several outstanding scientists to be featured in the book "Science, Not Art: Ten Scientists' Diaries".
References
1971 births
Living people
Theoretical physicists
Sierra Leone Creole people
Sierra Leonean scientists | Tanniemola Liverpool | [
"Physics"
] | 348 | [
"Theoretical physics",
"Theoretical physicists"
] |
57,612,705 | https://en.wikipedia.org/wiki/John%20Frank%20Schairer | J. Frank Schairer (13 April 1904, in Rochester, New York – 19 September 1970, near Point No Point, Maryland) was an American geochemist, mineralogist, and petrologist.
Schairer studied chemistry at Yale University with a bachelor's degree in 1925 and a doctorate in 1928. He was the president and one of the organizers of the undergraduate club "Yale Mineralogical Society" in 1923. In addition, he earned an M.S. in mineralogy. From 1927, he was a chemist at the Carnegie Institution Geophysical Laboratory in Washington, D.C. where he remained on the staff until mandatory retirement in 1969, when he became a part-time employee. He worked there with Norman L. Bowen in experimental petrology until Bowen's departure to the University Chicago in 1937. During World War II, the lab worked on military research (erosion in cannon and machine gun barrels). From the 1950s Schairer worked with Hatten Schuyler Yoder and Cecil Edgar Tilley on basalt fusions.
Schairer served from 1957 to 1960 as vice president of the International Association of Volcanology and Chemistry of the Earth's Interior, in 1944, vice president of the Geological Society of America, in 1960 president of the Geochemical Society and in 1943 president of the Mineralogical Society of America. He was also an accomplished botanist and co-founder of the National Capital Orchid Society (1947).
He married in 1940 and upon his death was survived by his widow, two children (twins), and four grandchildren.
Honors and memberships
Schairer was elected in 1953 a member of the National Academy of Sciences and in 1968 an honorary member of the Deutsche Mineralogische Gesellschaft (German Mineralogical Society).
He received in 1953 the Arthur L. Day Medal and in 1963 the Roebling Medal.
In 2012 he was inducted into the Appalachian Trail Hall of Fame for his extensive work in marking (under his leadership over 260 miles from 1928 to 1932 through the Potomac Appalachian Trail Club founded by him).
A mineral described by William F. Foshag in 1931 received the name schairerite in his honor.
References
American mineralogists
Petrologists
American geochemists
Members of the United States National Academy of Sciences
1904 births
1970 deaths
Yale University alumni
Presidents of the Geochemical Society
20th-century American chemists | John Frank Schairer | [
"Chemistry"
] | 476 | [
"Geochemists",
"Presidents of the Geochemical Society",
"American geochemists"
] |
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