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18,472,063 | https://en.wikipedia.org/wiki/LMC%20N49 | N49 or LMC N49 (PKS 0525-66, PKS B0525-661, PKS J0525-6604, SNR J052559-660453), also known as Brasil Nebula, is the brightest supernova remnant in the Large Magellanic Cloud, approximately 160,000 light-years from Earth. Its form has been assessed to be roughly 5,000 years old.
The latest pictures of N49 by the Chandra X-ray Observatory have revealed a bullet-shaped object traveling at about 5 million miles an hour away from a bright X-ray and gamma-ray point source, probably a neutron star with an extremely powerful magnetic field, known as a soft gamma repeater. A particularly strong gamma-ray burst from LMC N49 was detected on March 5, 1979.
References
Harvard-Smithsonian Center for Astrophysics, "N49: A supernova remnant in the Large Magellanic Cloud"
Dorado
Large Magellanic Cloud
Supernova remnants | LMC N49 | Astronomy | 210 |
2,333,181 | https://en.wikipedia.org/wiki/Kumkuma | Kumkuma is a powder used for social and religious markings in India. It is made from turmeric or any other local materials. The turmeric is dried and powdered with a bit of slaked lime, which turns the rich yellow powder into a red color.
In India, it is known by many names including kuṅkumam (Sanskrit कुङ्कुमम्, Tamil குங்குமம், and Malayalam കുങ്കുമം), kumkuma (Telugu కుంకుమ), kukum (Konkani कुकूम्), kunku (Marathi कुंकू), kanku (Gujarati કંકુ), kumkum (Bengali কুমকুম and Hindi कुमकुम), and kunkuma (Kannada ಕುಂಕುಮ).
Application
Kumkuma is most often applied by Indians to the forehead. The reason involves the ancient Indian belief that "the human body is divided into seven vortices of energy, called chakras, beginning at the base of the spine and ending at the top of the head. The sixth chakra, also known as the third eye, is centered in the forehead directly between the eyebrows and is believed to be the channel through which humankind opens spiritually to the Divine".
Thus, the kumkuma is placed where Indians believe to be the most important spot for receptivity to be enhanced.
Common forehead marks
Shaivites: Followers of Shiva usually apply three white horizontal lines (made from vibhuti) with a dot of kumkuma at the center. This is also known as tripundra.
Vaishnavas: Followers of Vishnu make use of "white clay to apply two vertical lines joined at the base and intersected by a bright red streak." Many times the clay is applied in a U-shape. This is known as Urdhva Pundra tilaka.
Shaktas: Shaktas of most Sampradayas usually apply a dot of vermillion in the center of the forehead with turmeric smeared around it.
Swaminarayana: Followers of the Swaminarayan faith apply kumkuma at the center of the forehead and between a U-shaped tilaka. The tilaka is normally yellow and made from sandalwood.
Chandrakor: Many Maharashtrians – men, women, and children alike – wear it traditionally in the shape of crescent moon.
Significance
In the Vaishnava tradition, the "white lines represent the footprint of their God, while the red refers to his consort, Lakshmi". The Swaminarayana tradition holds that the tilaka (yellow U-shaped mark) "is a symbol of the lotus feet of Paramatma," and the kumkuma "represents the bhakta" (devotee). In both of these traditions, the forehead mark serves as a reminder that a devotee of God should always remain protected at the feet of God.
The 'color' of the womb is yellow and is symbolically represented by turmeric. The blood stains on the womb is represented by kumkuma. It is believed that the combination of turmeric and kumkuma represents prosperity.
Kumkuma and women
When a girl or a married woman visits a house, it is a sign of respect (in case of an elderly lady) or blessings (in case of a girl) to offer kumkuma to them when they leave. However, normally it is not offered to widows(It is actually orthodoxy and superstition). If kumkuma is given to widow there will be no harm as 'bidhaba' or 'sadhaba' depends only on consideration, it's neither law of nature nor God.
Men, women, girls, and boys also apply a dot on their forehead of red turmeric powder, when visiting a temple or during a pooja. Kumkuma at temples is found in heaps. People dip their thumb or ring finger into the heap and apply it on the forehead or between the eyebrows.
In most of India, married women apply red kumkuma to the parting of their hair above their forehead every day as a symbol of marriage. This is called vermilion, or in Hindi, sindoor. In India, many unmarried girls wear a bindi every day.
Making kumkuma
Kumkum is made from turmeric by adding slaked lime.
Other uses
Kumkuma is also widely used for worshiping the Hindu goddesses, especially Shakti and Lakshmi, and kumkuma powder is thrown (along with other mixtures) into the air during Holi (the Festival of Colours), a popular Hindu spring festival.
Sanatan Sanstha has published an article which mentions that Kumkuma also is believed to prevent "negative energies entering the body".
See also
Haldi Kumkum
Bindi (decoration)
Tilaka
List of materials used in Hinduism
:Category:Hindu iconography
References
External links
Kumkum 2008
Lead in Spices, Herbal Remedies, and Ceremonial Powders Sampled from Home Investigations for Children with Elevated Blood Lead Levels — North Carolina, 2011–2018
Cosmetics
Hairdressing
Marriage in India
Marriage in Hinduism
Powders | Kumkuma | Physics | 1,065 |
78,456,163 | https://en.wikipedia.org/wiki/Loop%20extrusion | Loop extrusion is a major mechanism of Nuclear organization. It is a dynamic process in which structural maintenance of chromosomes (SMC) protein complexes progressively grow loops of DNA or chromatin. In this process, SMC complexes, such as condensin or cohesin, bind to DNA/chromatin, use ATP-driven motor activity to reel in DNA, and as a result, extrude the collected DNA as a loop.
Background
The organization of DNA presents a remarkable biological challenge: human DNA can reach 2 meters and is packed into the nucleus with the diameter of 5-20 µm. At the same time, the critical cell processes involve complex processes on highly compacted DNA, such as transcription, replication, recombination, DNA repair, and cell division.
Loop extrusion is a key mechanism that organizes DNA into loops, enabling its efficient compaction and functional organization. For instance, in vitro experiments show that cohesin can compact DNA by 80%, while condensin achieves a remarkable 10,000-fold compaction of mitotic chromosomes, as evidenced by microscopy, Hi-C, and polymer simulations.
Another challenge lies in establishing long-range genomic communication, which can span hundreds of thousands of base pairs. Physical encounters between genomic elements are intrinsically random and promiscuous without mechanisms to facilitate them. Loop extrusion has been proposed to provide an effective solution to regulate contacts by bringing target elements into proximity while limiting contact with unwanted loci.
Key components
The key components of the loop extrusion process are
DNA molecule that serves as the substrate for the movement of extruder
Extruders, usually SMC complexes, that moves along DNA in ATP-dependent manner
Accessory factors
Loaders of the extruder, a factor that facilitates loading of extruder on DNA (NIPBL/MAU2 usually play the key role in loading extruder on DNA)
Unloaders of the extruder, the molecule that facilitates detachment of extruder from DNA (for example, WAPL)
Road-blocks located on DNA that present a hindrance to extruder movement and lead to stalling of the extrusion machinery.
SMC proteins
Loop extrusion is performed by the SMC family of protein-complexes which includes cohesin, condensin, and SMC5/6 each playing specialized roles depending on the organism, cell cycle phase, and biological context. Cohesin mediates chromatin loop formation and stabilization, particularly during interphase in vertebrates, where it facilitates transcriptional regulation by promoting distal enhancer-promoter interactions. During mitosis and meiosis, cohesin dissociates from chromosome arms ceding its loop extrusion role to condensin. Loop extrusion by condensin mediates large-scale chromosome compaction, creating the compact, rod-like chromosome structures required for accurate segregation. Unlike cohesin and condensin, SMC5/6 is a loop extruding factor which primarily functions in maintaining genome integrity during DNA damage repair and resolving replication stress.
Despite their distinct roles, SMC complexes share a highly conserved ring-like structure. Two SMC proteins (usually, SMC1 and SMC3) are connected via a hinge region and linked at their heads by a kleisin subunit, forming a closed ring. These two SMC proteins have ATPase domains at their heads, which bind together and hydrolyze ATP. Cycles of ATP binding and hydrolysis mediate conformational changes in the ring structure, driving DNA translocation and stepwise loop extrusion. ATP is essential for both initiating loop extrusion (e.g., loading SMC complexes onto DNA) and propagating it (growing loops by translocating along DNA). The tension within the DNA significantly influences extrusion efficiency. At low tension, SMC complexes can make larger loop-capture steps, while higher tension can lead to stalling or reversal of loop extrusion.
Modifications and factors for loading/unloading
The dynamic nature of loop extrusion is tightly controlled by accessory factors and post-translational modifications, especially in the case of cohesin. In vertebrates, NIPBL (and orthologs like Mau2 in yeast or SCC2 and SCC4) is crucial for loading SMC complexes onto DNA, initiating and maintaining active extrusion. PDS5 is thought to pause the extrusion process. The SMC can then either restart extruding or be unloaded by the additional binding of WAPL, which ensure proper recycling and turnover. Post-translational modifications also play a key role. Acetylation of cohesin by enzymes such as ESCO1 and ESCO2 stabilizes chromatin loops, particularly at CTCF-bound sites. Similarly, SUMOylation, mediated by the NSE2 subunit of the SMC5/6 complex, enhances the recruitment of SMC5/6 to sites of DNA damage, supporting its role in genomic stability.
Roadblocks of loop extrusion
Loop extruders can encounter various obstacles while extruding. For example, many of which were shown to directly interact with cohesin and hypothesized to stop its movement on DNA. However, in vivo experiments demonstrate that cohesin can frequently bypass obstacles larger than its ring size.
Other cohesin and condensin molecules: Extruding cohesins and condensins has been found to be obstacle to other extruders that they encounter on the way. As such, they present a fundamental road-block that can be randomly encountered on the DNA.
CTCF: The C-terminal DNA-binding domain of CTCF has been shown to directly interact with SA2 and SCC1 subunits of cohesin to stop extrusion and retain it on DNA with recent evidence suggesting a tension-dependence to the interaction. CTCF stalls cohesin in a highly directional manner where cohesin can bypass CTCF in one orientation but stalls when encountering it in the opposite orientation. This directionality allows for the creation of isolated domains on the genome called Topologically Associating Domains (TADs) which have been proposed to have a large role in gene-regulation.
Polymerase: Transcribing polymerases can serve as barriers to cohesin that may not only stall extruders but also act as a motor pushing cohesin in the direction of polymerase movement. The size of a polymerase with an RNA transcript is usually larger than the size of the cohesin ring, and the stall force of cohesin is much smaller than that of polymerase, allowing for effective barrier function by polymerase. Furthermore, it has been found that RNA can directly interact with cohesin subunits.
Helicase: MCM helicase has been found to counteract the extrusion of cohesin on DNA.
R-loops: Some evidence suggests that R-loops can also act as barriers to loop extrusion, and R-loops have been shown to interact with cohesin subunits. However, other evidence suggests that R-loops may instead act as cohesin loaders.
Molecular mechanism
The molecular mechanisms of DNA-loop extrusion by SMC proteins have not yet been fully understood, but recent structural studies have made significant progress in developing several working models, like the scrunching model, the Brownian-ratchet model, the DNA-segment capture model/DNA-pumping model, the hold-and-feed model and the swing-and-clamp model.
Evidence for loop extrusion
Evidence for loop extruding molecules and their properties
The first direct evidence of loop extrusion came from in vitro imaging studies on fluorescently labeled DNA with condensin or cohesin. Extrusion was found to be ATP-dependent and happened at ~1-3kb/s. The stall force was measured to be around 0.1-1pN which is small compared to other molecular motors.
Evidence for the biological role of loop extrusion
Most work on the biological role of loop extrusion relies on inhibiting loop extruders and observing the consequences. Depletion of cohesin leads to the disappearance of TADs and some loss in transcription genome-wide. In more specific settings, inhibition of cohesin has been found to inhibit neuronal maturation and differentiation and function of dendritic cells. Depletion of either condensin I or condensin II at the entry into mitosis leads to abnormal chromosome formation and improper segregation of sister chromatids.
Biological function
Loop extrusion has been found across the tree of life with suggested roles in immune response, DNA repair, enhancer-promoter interactions, and mitosis.
Mitosis in eukaryotes: In mitosis, loop extrusion by condensin is critical for the segregation of sister chromatids and for providing structural rigidity after separation. Condensin I has been found to modulate the size and arrangement of nested inner loops and condensin II organizing the backbone from which loops emanate.
Cell division in bacteria: In bacteria, SMC proteins have been found to maintain the juxtaposition of the chromosome arms by loading at the centromere and extruding until the terminus.
Topologically associating domains (TADs): During interphase, chromosomes are locally compacted at the sub-megabase scale into so-called TADs. Generally, they are bordered by motifs for CTCF and completely disappear if either cohesin or CTCF is degraded.
V(D)J recombination: Loop extrusion by cohesin has been found to play a key role in V(D)J recombination to generate diversity in antibodies and T-cell receptors as depletion of cohesin inhibits V(D)J recombination. There are CTCF motifs throughout the recombination region, and inversions of their orientation or mutation of the motifs lead to changes in recombination probabilities consistent with those predicted by loop extrusion.
Protocadherin promoter choice: Protocadherins are mammalian proteins involved in cell adhesion of the neurons encoded in DNA in multiple similar genes located in the protocadherin locus. Neurons usually express only a subset of the protocadherins, enabling variability in the interactions between neurons. The choice of protocadherins rely on cohesin, which bridges alternative promoters of protocadherin with the enhancer in a CTCF-dependent manner. This process involves intricate regulation by CTCF and WAPL.
Theoretical models of loop extrusion
In mathematical models of loop extrusion, the two legs of a loop-extruding factor (LEF) are represented as points on a one-dimensional line, evolving according to different extrusion policies:
LEF Translocation: These dictate how LEFs move along the chromatin. These include symmetric extrusion—where both legs move in opposite directions—and one-sided extrusion—where one leg remains stalled while the other moves. Cohesin is often modeled with symmetric extrusion, while condensin is thought to follow a one-sided extrusion mechanism.
Stochastic Binding and Unbinding: LEFs bind to chromatin at a random time and position along the chain, and unbind after a characteristic time.
LEF-LEF interactions: When LEFs encounter one another, different interaction policies can be implemented. LEFs may halt upon collision, or bypass each other, as observed in some contexts.
Extrusion Barriers: Bound proteins such as CTCF or RNA polymerase II can act as obstacles, stalling or halting LEF motion.
Since the exact modalities of LEF dynamics remain uncertain, these models provide a flexible framework to explore different hypothetical behaviors of LEFs.
In these models, the statistics of LEFs are characterized by two key physical parameters:
Processivity (): Average size of a loop extruded by an unobstructed LEF before dissociating. This characteristic loop size depends on the extrusion speed and the residence time of the LEF on the chromatin.
Separation (): Average distance between LEFs on the chromatin fiber. It is determined by the total number of LEFs and the length of the chromatin . A shorter separation results in denser packing of loops, while larger separation leaves gaps between loops.
The interplay of these two parameters, encapsulated by the dimensionless parameter , defines two states of chromatin organization:
Sparse State (): LEFs operate independently, forming isolated loops with large gaps between them. This state results in minimal compaction of the chromatin fiber.
Dense State (): LEFs are abundant enough to form a continuous, gapless array of loops. This leads to significant chromatin compaction, as seen during mitosis.
References
Nuclear organization | Loop extrusion | Biology | 2,714 |
7,898,478 | https://en.wikipedia.org/wiki/Jamal%20ad-Din%20Bukhari |
Jamal ad-Din Muḥammad ibn Ṭāhir ibn Muḥammad al‐Zaydī al‐Bukhārī (variously transcribed Jamal ud-Din, Jamal al-Din ( Beauty of Faith), etc., Chinese name Zhamaluding) was a 13th-century Persian astronomer. Originally from Bukhara, he entered the service of Kublai Khan around the 1250s to set up the Islamic Astronomical Bureau in the new capital of Beijing, to operate in parallel with the traditional Chinese bureau. Kublai Khan thus maintained the bureaucratic structure, but allowed Chinese observations and predictions to be checked by respected Muslim scholars.
He is credited with having taken seven astronomical instruments to Kublai Khan, as a present from Hulagu Khan including a Persian astrolabe, a globe and an armillary sphere, in 1267. This is the earliest known reference to a spherical terrestrial globe of the Earth in Chinese astronomy.
He is associated with a zij in Persian which has been lost but was translated into Chinese in 1383 by Ma‐shayihei with the title Huihuilifa (Islamic calendar). This contained Ptolemaic tables based on new values and adjusted to Beijing and has been reconstructed in recent years.
In general, the activity of the Islamic Astronomical Bureau didn't make much difference to Chinese astronomy. However Guo Shoujing did evidently gain the idea of the torquetum from him (which he didn't bring), and produced a simplified version which omitted ecliptic coordinates which were not used in China.
In 1286 he carried out a large-scale survey of the Yuan empire which was produced in 755 volumes as the Dayitongzh. All but the introduction of this has been lost.
See also
Islam in China
Notes
References
(PDF version)
Islam in China
13th-century Iranian astronomers
Year of death unknown
Yuan dynasty people
People from Bukhara
Year of birth unknown
Mongol Empire scholars
Yuan dynasty Muslims
Globe makers | Jamal ad-Din Bukhari | Astronomy | 394 |
11,377,382 | https://en.wikipedia.org/wiki/Architectural%20animation | Architectural animation is a short architectural movie created on a computer. A computer-generated building is created along with landscaping and sometimes moving people and vehicles. Unlike an architectural rendering, which is a single image from a single point of view, an architectural animation is generally a series of hundreds or even thousands of still images played simultaneously in order to produce a video. When these images are assembled and played back, they produce a movie effect much like a real movie camera except all images are artificially created by computer. It is possible to add a computer-created environment around the building to enhance reality and to better convey its relationship to the surrounding area; this can all be done before the project is built giving designers and stakeholders a realistic view of the completed project. Architectural renderings are often used along with architectural animation.
History
The first use of a 3D hidden-line removal movie depicting an architectural street scene was in 1976 by Jonathan Ingram. It shows the planned Crown Courts in Hobart in 1976 and was used for planning approval. The buildings exist today.
Usage
Commercial demand for computer-generated rendering is on the rise. There is a large growing demand of architectural visualization services worldwide. This has mainly been accelerated by the advancements in computing technology and allowing architectural animations to become cheaper. There are numerous real-time rendering engines that differ from the traditional method of multiple stitched still images together. This allows architectural animation to be far cheaper and less labor-intensive. However, it usually doesn't have the same photo realism. Typically, members of the AIA (American Institute of Architects) and NAHB (National Association of Home Builders) prefer to use 3D animations and single renderings for their customers before starting on a construction project. These professionals often find their clients are unable to grasp the complexity and spatial qualities of large projects without the help of computer generated visual aids. The animations and renderings are usually supplied by small animation studios.
The process
The process of creating an architectural animation is generally standard across the industry. A storyboard will be created showing the path of the animation, this allows for the project to have a clear scope of work and an estimation of how much time it is going to take. Once complete, the general 3D structure of the animation sequence is created and textures, materials & details are applied. Single still frame images are usually presented to the client at this stage and tweaks are made to the design so the structure, materials and colors are correct. Once this has been accepted by the client the images that form the sequence are created and stitched together, edited and presented with a soundtrack.
Future
Architectural animation is not necessarily the ambition of most small computer rendering firms because of the man hours and computer time that is required to create so many single still images. Although, due to the rapid improvements in software and rendering engines it is going to very prevalent in future. Architectural animations require a larger team of artists and animators than single renderings and a much longer time frame is required to complete an animation project. However, many architectural firms are now using architectural animation because it attracts investors and customers who may not know much about building designs and can prefer visualization rather than technical drawings to see the buildings look and features. Architectural animation is considered to have a bright future ahead as more and more architects and real estate developers are including computer animations in their marketing programs.
See also
Computer animation
3D computer graphics
Architectural rendering
References
External links
American Institute of Architects Official website
National Association of Home Builders Official website
Architectural design
Computer-aided design | Architectural animation | Engineering | 709 |
14,263,768 | https://en.wikipedia.org/wiki/Ammonium%20adipate | Ammonium adipate is a compound with formula (NH4)2(C4H8(COO)2). It is the ammonium salt of adipic acid. It is used as a food additive and has the E number E359.
Adipates
Ammonium compounds
Food additives | Ammonium adipate | Chemistry | 64 |
71,616,465 | https://en.wikipedia.org/wiki/Threohydrobupropion | Threohydrobupropion (developmental code names BW 494, BW A494U) is a substituted amphetamine derivative—specifically a β-hydroxyamphetamine—and a major active metabolite of the antidepressant drug bupropion (Wellbutrin). Bupropion is a norepinephrine–dopamine reuptake inhibitor and nicotinic acetylcholine receptor negative allosteric modulator, with its metabolites contributing substantially to its activities.
Chemistry
Threohydrobupropion exists as a racemic mixture of two stereoisomers, (1R,2R)-threohydrobupropion and (1S,2S)-threohydrobupropion. Other metabolites of bupropion include hydroxybupropion and erythrohydrobupropion.
Pharmacology
Information on the pharmacological actions of threohydrobupropion is scarce. In any case, it is about 20% as pharmacologically potent as bupropion and in the range of 20 to 50% as potent as bupropion in mouse models of depression. Moreover, threohydrobupropion has been reported to weakly inhibit the reuptake of norepinephrine, dopamine, and serotonin with rat or Ki values of 16μM, 47μM, and 67μM, respectively. These values can be compared to rat values with bupropion of 1,400nM, 570nM, and 19,000nM, respectively. Besides monoamine reuptake inhibition, threohydrobupropion has also been reported to inhibit α3β4 nicotinic acetylcholine receptors, with an IC50 value of 14μM. Threohydrobupropion circulates at higher concentrations than bupropion during bupropion therapy, similarly to hydroxybupropion but in contrast to erythrohydrobupropion—which circulates at similar concentrations as bupropion.
The plasma protein binding of threohydrobupropion is 42%. Threohydrobupropion is formed from bupropion via reduction of the ketone group by 11β-hydroxysteroid dehydrogenase-1 and aldo-keto reductases. It can also be formed from bupropion by carbonyl reductases. The compound is metabolized by the cytochrome P450 enzymes CYP2B6 and CYP2C19 into threo-4'-hydroxy-hydrobupropion and by various glucuronosyltransferase enzymes into glucuronide conjugates. Its elimination half-life is approximately 37hours.
Dry mouth during bupropion therapy has been associated with threohydrobupropion concentrations. Administration of threohydrobupropion in mice produces seizures at sufficiently high doses similarly to bupropion and other metabolites. Threohydrobupropion is a CYP2D6 inhibitor and accounts for about 21% of CYP2D6 inhibition during bupropion therapy, with hydroxybupropion accounting for 65% and erythrohydrobupropion accounting for 9%.
References
Antidepressants
Beta-Hydroxyamphetamines
3-Chlorophenyl compounds
Convulsants
Human drug metabolites
Nicotinic antagonists
Secondary alcohols
Secondary amines
Serotonin–norepinephrine–dopamine reuptake inhibitors
Tert-butyl compounds | Threohydrobupropion | Chemistry | 814 |
7,667,105 | https://en.wikipedia.org/wiki/Xerox%20PARC%20Map%20Viewer | Xerox PARC Map Viewer was one of the earliest static web mapping sites, developed by Steve Putz in June 1993 at Xerox Corporation's Palo Alto Research Center (PARC). The Xerox PARC Map Viewer was an experiment in providing interactive information retrieval, rather than access to just static files, on the World Wide Web.
Map Viewer used a customized CGI server module written in Perl. Map images were generated in GIF format from two server side programs. MAP-WRITER created the raster images from the geographic database and RASTOGIF would convert the raster image into the GIF format.
Xerox has since discontinued the Map Viewer service.
References
External links
About the Xerox PARC Map Viewer
An Interactive Map Viewer, section from that paper describing the map server
Web mapping
Parc Map Viewer | Xerox PARC Map Viewer | Technology | 168 |
59,958,774 | https://en.wikipedia.org/wiki/NGC%204095 | NGC 4095 is an elliptical galaxy located 330 million light-years away in the constellation Coma Berenices. The galaxy was discovered by astronomer William Herschel on April 26, 1785. NGC 4095 is a member of the NGC 4065 Group and is a LINER.
See also
List of NGC objects (4001–5000)
References
External links
4095
038324
Coma Berenices
Astronomical objects discovered in 1785
Elliptical galaxies
NGC 4065 Group
LINER galaxies | NGC 4095 | Astronomy | 97 |
24,508,684 | https://en.wikipedia.org/wiki/Gymnopilus%20pleurocystidiatus | Gymnopilus pleurocystidiatus is a species of mushroom in the family Hymenogastraceae.
See also
List of Gymnopilus species
External links
Gymnopilus pleurocystidiatus at Index Fungorum
pleurocystidiatus
Fungi of North America
Fungus species | Gymnopilus pleurocystidiatus | Biology | 65 |
9,403,552 | https://en.wikipedia.org/wiki/Situated%20robotics | In artificial intelligence and cognitive science, the term situated refers to an agent which is embedded in an environment. In this used, the term is used to refer to robots, but some researchers argue that software agents can also be situated if:
they exist in a dynamic (rapidly changing) environment, which
they can manipulate or change through their actions, and which
they can sense or perceive.
Being situated is generally considered to be part of being embodied, but it is useful to take both perspectives. The situated perspective emphasizes the environment and the agent's interactions with it. These interactions define an agent's embodiment.
See also
Robot general heading
Cognitive agents
Scruffies - people who tend to worry about whether their agent is situated.
References
Hendriks-Jansen, Horst (1996) Catching Ourselves in the Act: Situated Activity, Interactive Emergence, Evolution, and Human Thought. Cambridge, Mass.: MIT Press.
Robotics | Situated robotics | Engineering | 187 |
213,739 | https://en.wikipedia.org/wiki/Dry%20dock | A dry dock (sometimes drydock or dry-dock) is a narrow basin or vessel that can be flooded to allow a load to be floated in, then drained to allow that load to come to rest on a dry platform. Dry docks are used for the construction, maintenance, and repair of ships, boats, and other watercraft.
History
China
The use of dry docks in China goes at least as far back as the 10th century A.D. In 1088, Song dynasty scientist and statesman Shen Kuo (1031–1095) wrote in his Dream Pool Essays:
Europe
Greco-Roman world
The Greek author Athenaeus of Naucratis (V 204c-d) reports something that may have been a dry dock in Ptolemaic Egypt in the reign of Ptolemy IV Philopator (221-204 BC) on the occasion of the launch of the enormous Tessarakonteres rowing ship. However a more recent survey by Goodchild and Forbes does not substantiate its existence.
It has been calculated that a dock for a vessel of such a size might have had a volume of 750,000 gallons of water.
Renaissance Europe
Before the 15th century, when the hull below the waterline needed attention, careening was practised: at high tide the vessel was floated over a beach of hard sand and allowed to rest on one side when the tide receded. An account of 1434 described how a site near Southampton with a bottom of soft mud was selected for the warship Grace Dieu, so that the hull would bed itself in and remain upright at low tide. A timber, brushwood and clay wall was then built up around the hull. The first early modern purpose-built European and oldest surviving dry dock still in use was commissioned by Henry VII of England at HMNB Portsmouth in 1495. This was a timber-lined excavation, with the seaward end closed off by a temporary revetted bank of rock and clay that had to be dug away by hand (an operation taking typically 29 days, working night and day to accord with the tides) to allow the passage of a ship. Emptying was by a pump, possibly in the form of a bucket-chain powered by horses. This dry dock currently holds First World War monitor HMS M33.
Possibly the earliest description of a floating dock comes from a small Italian book printed in Venice in 1560, called Descrittione dell'artifitiosa machina. In the booklet, an unknown author asks for the privilege of using a new method for the salvaging of a grounded ship and then proceeds to describe and illustrate his approach. The included woodcut shows a ship flanked by two large floating trestles, forming a roof above the vessel. The ship is pulled in an upright position by a number of ropes attached to the superstructure.
Modern era
The Saint-Nazaire's Chantiers de l'Atlantique owns one of the biggest in the world: . The Alfredo da Silva Dry Dock in Almada, Portugal, was closed in 2000. The largest roofed dry dock is at the German Meyer Werft Shipyard in Papenburg, Germany, it is 504 m long, 125 m wide and stands 75 m tall.
Harland and Wolff Heavy Industries in Belfast, Northern Ireland, is the site of a large dry dock . The massive cranes are named after the Biblical figures Samson and Goliath.
Dry Dock 12 at Newport News Shipbuilding at is the largest dry dock in the United States. The largest floating-dock in North America is named The Vigorous. It is operated by Vigor Industries in Portland, OR, in the Swan Island industrial area along the Willamette River.
Types
Graving
A is the traditional form of dry dock. It is a narrow basin, usually made of earthen berms and concrete, closed by gates or a caisson. A vessel is floated in with the gates open, then the gates are closed and the water is pumped out, leaving the craft supported on blocks.
The keel blocks as well as the bilge block are placed on the floor of the dock in accordance with the "docking plan" of the ship. Routine use of dry docks is for the "graving" i.e. the cleaning, removal of barnacles and rust, and re-painting of ships' hulls.
Some fine-tuning of the ship's position can be done by divers while there is still some water left to manoeuvre the vessel. It is extremely important that supporting blocks conform to the structural members so that the ship is not damaged when its weight is supported by the blocks. Some anti-submarine warfare warships have sonar domes protruding beneath the hull, requiring the hull to be supported several metres above the bottom of the dry dock, or depressions built into the floor of the dock, to accommodate the protrusions.
Once the remainder of the water is pumped out, the ship can be freely inspected or serviced. When work on the ship is finished, the gates are opened to allow water in, and the ship is carefully refloated.
Modern graving docks are box-shaped, to accommodate newer, boxier ships, whereas old dry docks are often shaped like the ships expected to dock there. This shaping was advantageous because such a dock was easier to build, it was easier to side-support the ships, and less water had to be pumped away.
Dry docks used for building naval vessels may occasionally be built with a roof, to prevent spy satellites from taking pictures of the dry dock and any vessels that may be in it. During World War II, the German used fortified dry docks to protect its submarines from Allied air raids (see submarine pen).
An advantage of covered dry docks is that work can take place in any weather; this is frequently used by modern shipyards for construction especially of complex, high-value vessels like cruise ships, where delays would incur a high cost.
Floating
A floating dry dock is a type of pontoon for dry docking ships, possessing floodable buoyancy chambers and a U-shaped cross-section. The walls are used to give the dry dock stability when the floor or deck is below the surface of the water. When valves are opened, the chambers fill with water, causing the dry dock to float lower in the water. The deck becomes submerged and this allows a ship to be moved into position inside. When the water is pumped out of the chambers, the dry dock rises and the ship is lifted out of the water on the rising deck, allowing work to proceed on the ship's hull.
A large floating dry dock involves multiple rectangular sections. These sections can be combined to handle ships of various lengths, and the sections themselves can come in different dimensions. Each section contains its own equipment for emptying the ballast and to provide the required services, and the addition of a bow section can facilitate the towing of the dry dock once assembled. For smaller boats, one-piece floating dry docks can be constructed or converted out of an existing obsolete barge, potentially coming with their own bow and steering mechanism.
Shipyards operate floating dry docks as one method for hauling or docking vessels. Floating drydocks are important in locations where porous ground prevents the use of conventional drydocks, such as at the Royal Naval Dockyard on the limestone archipelago of Bermuda. Another advantage of floating dry docks is that they can be moved to wherever they are needed and can also be sold second-hand. During World War II, the U.S. Navy used such auxiliary floating drydocks extensively to provide maintenance in remote locations. Two examples of these were the 1,000-foot AFDB-1 and the 850-foot AFDB-3. The latter, an Advance Base Sectional Dock which saw action in Guam, was mothballed near Norfolk, Virginia, and was eventually towed to Portland, Maine, to become part of Bath Iron Works' repair facilities.
A downside of floating dry docks is that unscheduled sinkings and off-design dives may take place, as with the Russian dock PD-50 in 2018.
The "Hughes Mining Barge", or HMB-1, is a covered, floating drydock that is also submersible to support the secret transfer of a mechanical lifting device underneath the Glomar Explorer ship, as well as the development of the Sea Shadow stealth ship.
The Great Balance Dock, built in New York City in 1854, was the largest floating drydock in the world when it was launched. It was long and could lift 8,000 tons, accommodating the largest ships of its day.
Alternative dry dock systems
Apart from graving docks and floating dry docks, ships can also be dry docked and launched by:
Marine railway — For repair of larger ships up to about 3000 tons ship weight
Shiplift — For repair as well as for new-building. From 800 to 25000 ton ship-weight
Slipway, patent slip — For repair of smaller boats and the new-building launch of larger vessels
Other uses
Some dry docks are used during the construction of bridges, dams, and other large objects. For example, the dry dock on the artificial island of Neeltje-Jans was used for the construction of the Oosterscheldekering, a large dam in the Netherlands that consists of 65 concrete pillars weighing 18,000 tonnes each. The pillars were constructed in a drydock and towed to their final place on the seabed.
A dry dock may also be used for the prefabrication of the elements of an immersed tube tunnel, before they are floated into position, as was done with Boston's Silver Line.
Gallery
See also
on a dry dock during World War II
References
Sources
External links
dry-dock in the Encyclopædia Britannica
Carnival Liberty Cruise Ship in Dry Dock in Freeport, Grand Bahamas
"Docks's Life"—All about floating docks of shipbuilding firm Almaz of St. Petersburg, Russia
Coastal construction | Dry dock | Engineering | 2,024 |
380,702 | https://en.wikipedia.org/wiki/Nocnitsa | In Slavic mythology, notsnitsa (, , , , , , , ), often referred in plural, is a nightmare spirit or demon that torments people and especially children at night. Other names for notsnitsa in East Slavic languages include kriksy, plaksy, plachky, plaksivicy, kriksy-varaksy, kriksy-plaksy, night hag, night maiden.
Folklore
In Russian and Slovak folklore, notsnitsa are known to torment children at night, and a stone with a hole in the center is said to be a protection from nocnitsa. Mothers in some regions will place a knife in their children's cradles or draw a circle around the cradles with a knife for protection. This is possibly based on the belief that supernatural beings cannot touch iron.
Nocnitsa is known to sit on one's chest, drawing "life energy". Because of this, many refer to nocnitsa as a type of vampire. Nocnitsa will often continue visiting. According to some folklore, night hags visit when one sleeps on one's back, with the hands on the chest (a position allegedly called "sleeping with the dead"). According to some folklore, night hags are made of shadow. She might also have a horrible screeching voice. She might allegedly also smell of the moss and dirt from her forest of origin.
Nocnitsa is linked to the common apparition seen during the hypnagogic state of sleep.
In popular culture
A creature, considered by the characters to be a nocnitsa, is depicted in a 2017 horror movie Slumber.
There is a nocnitsa in the supernatural novel Night Terror by John Passarella.
In the book Coraline, by Neil Gaiman, a Nocnitsa poses as Coraline's alternate dimension mother. Coraline, however, has a stone with a hole in it which protects her.
It is often believed throughout the Middle East that this mythological creature came into people's homes at night, and would watch their children sleep if they did not behave.
In the Iron Druid Chronicles book Staked Protagonist, Granuaile MacTiernan alongside Slavic Thunder God Perun and the Orisha Shango are attacked by a group of Nocnitsa.
See also
Lilin
Muma Pădurii
Night hag
Nochnitsa, a genus named after the mythological creature
References
Slavic legendary creatures
Female legendary creatures
Sleep in mythology and folklore | Nocnitsa | Biology | 523 |
50,975,292 | https://en.wikipedia.org/wiki/Denintuzumab%20mafodotin | Denintuzumab mafodotin (INN; development codes SGN-19A or SGN-CD19A) is a humanized monoclonal antibody-drug conjugate designed for the treatment of CD19-positive acute lymphoblastic leukemia and B-cell non-Hodgkin lymphoma. It consists of an anti-CD19 mAb linked to monomethyl auristatin F (MMAF), a cytotoxic agent. This drug was developed by Seattle Genetics.
Denintuzumab refers to the anti-CD19 antibody, and mafodotin refers to MMAF and the chemical linkage.
Clinical trials
The drug is in phase I clinical trials.
Preliminary phase I results for B-cell malignancies, including diffuse large B-cell lymphoma (DLBCL) and B-lineage acute lymphocytic leukemia (B-ALL) were presented at the ASH medical conference Dec 2015.
Phase 2
A separate randomized phase 2 trial started in 2015 to evaluate SGN-CD19A in combination with R-ICE chemotherapy for second-line DLBCL. A phase 2 clinical trial in front-line DLBCL is started in 2016. Both trials were terminated by the sponsor based on portfolio prioritization.
References
Antibody-drug conjugates
Experimental cancer drugs
Monoclonal antibodies for tumors | Denintuzumab mafodotin | Biology | 288 |
5,847,346 | https://en.wikipedia.org/wiki/Jannis%20Kallinikos | Jannis Kallinikos (; b. 1954) is an organization and communication scholar and intellectual. He was born in the town of Preveza, western Greece. He is also a citizen of Sweden. Kallinikos is currently a professor in the Information Systems and Innovation Group, Department of Management at the London School of Economics and Political Science (LSE). His scholarly projects have over the years covered several themes ranging from the significance writing and notation has assumed in the making of modern organizations through the understanding of markets as semiotic systems to the study of bureaucracy and institutions. His concerns have recently shifted to the investigation of the conditions associated with the penetration of the social and economic fabric by technological information. Kallinikos calls this emerging socio-economic environment, marked by the ubiquitous presence of the Internet, information-based services and software-mediated culture, the habitat of information. The term indicates that the growing involvement of information in society, economy and culture is associated with important changes in the ways institutions operate as well as shifts in behavioural, cognitive and communicative habits.
Education
Kallinikos completed his undergraduate studies in the Athens University of Economics and Business in 1977 and moved to Sweden for postgraduate studies at the Department of Business Studies at Uppsala University. After completing his MSc in 1979 Kallinikos pursued doctoral studies and was awarded his PhD in 1985 from the same department.
Academic career
In 2001, Kallinikos joined the Department of Information Systems at LSE when Claudio Ciborra was in charge of it. The department merged in 2006 with three other departments into a newly founded Department of Management. Kallinikos has been a visiting professor at various universities, including the University of Bologna, Uppsala University, Växjö University, Umeå University, University of Macedonia, Greece, Stanford University and the European Institute of Advanced Studies in Brussels. LSE promoted him to full professor in 2007. Kallinikos served as member of the LSE Research Committee (2003–2008) research chair of the Information systems and Innovation group (2005–2008) and director of the MSc Programme in Information Systems and Organizations Research (ISOR) (2006–2008).
Research area
Kallinikos's research comprises the study of formal organizations with specific emphasis on the range of objectified techniques and methods by which organizations are constructed as particular social entities and rendered predictable and durable. The study of information, information technology and information systems forms part of that intellectual project. According to Kallinikos, the proliferation of digital means of information processing and transmission, and the growing involvement of the Internet in social life are altering the socio-economic environment in which organizations and institutions are embedded.
Over the last years Kallinikos has worked on the idea of the information habitat to capture how increasingly abstract and disembedded data processing and calculation restructure organizations and institutions. He sees information technologies as electronic successors to writing, notation and paper-based means of dealing with information. In this new setting underpinned to a great extent by the internet, information is increasingly generated out of existing information through a variety of automated and autonomic procedures afforded by interconnected information systems and computer technology. In order to study the habitat of information, Kallinikos has formed The Information Growth And Internet Research Group (TIGAIR).
In his recent research, he further elaborated on his framework of Information Growth and Information Habitat by focusing on the ephemeral and amorphous nature of digital objects (e.g. software applications, hypertext documents, computer games, etc.) which differ from material, physical objects in non-trivial ways. At the core of his Theory of Digital Objects lies the argument that digital objects are to be seen as computational operations. Digital objects are objects only in a euphemistic sense. With this argument, Kallinikos has become a strong advocate for a small but growing community of social scientists, such as Jochen Runde and Philip Faulkner from the University of Cambridge, UK, or Paul Leonardi from Northwestern University, Illinois) who share a common interest in the research on ICT enabled, digital and immaterial objects and their ontological modes of existence in various institutional fields and organizations.
Kallinikos's overall outlook is constructivist in the sense of focusing on the semiotic and communicative means by which social reality is fashioned and made durable. However, drawing upon scholars such as Shoshana Zuboff, Nelson Goodman, Niklas Luhmann and Albert Borgmann, Kallinikos has sought to distance himself from popular constructivist approaches and their focus on local settings. He has claimed in several of his works that information and communication technologies mediate a coherent set of principles for framing and acting upon reality. The social and behavioural implications of such principles transcend the human-technology interface and cannot be sufficiently studied as an instance of local adaptation and interpretation of technological systems and artifacts by willful agents.
Selected publications
Kallinikos has published numerous monographs, peer-reviewed articles, book chapters, reviews, and edited several books. A representative picture of Kallinikos's thinking can be found in:
Governing Through Technology. Information Artefacts and Social Practice, Palgrave Macmillan. 2010.
The Consequences Of Information: Institutional Implications of Technological Change. Edward Elgar. 2006.
Other key publications include:
(with Aaltonen, A. and Marton, A.) A Theory of Digital Objects. First Monday 15(6), 2010.
On the Computational Rendition of Reality: Artefacts and Human Agency, Organization, 16/2: 183–202, 2009.
(with Nardi, B.) Human-Computer Interaction. In Donsbach, W. (ed.): International Encyclopedia of Communication and ICT. Blackwell. 2008.
Information Technology, Contingency and Risk. In Hanseth, O. and Ciborra, C. (eds): Risk, Complexity and ICT. Edward Elgar. 2007.
The Order of Technology: Complexity and Control in a Connected World. Information and Organization 15(3):185–202. 2005
Farewell to Constructivism: Technology and Context-Embedded Action. In Avgerou et al. (eds): The Social Study of Information and Communication Technology. Oxford University Press. 2004.
Deconstructing Information Packages: Organizational and Behavioural Implications of ERP Systems. Information Technology and People 17(1): 8–30. 2004.
The Social Foundations of the Bureaucratic Order. Organization, 11/1: 13–36, 2004.
(with Hasselbladh, H.) The Project of Rationalization: A Critique and Reappraisal of Institutionalism in Organization Studies. Organization Studies, 21/4: 697–720., 2000.
Technology and Society: Interdisciplinary Studies in Formal Organization. ACCEDO. 1996.
Cognitive Foundations of Economic Institutions: Markets, Organizations and Networks Revisited, Scandinavian Journal of Management, 11/2: 119–137.
(with Mariátegui, J.-C.) Video as digital object: production and distribution of video content in the internet media ecosystem. The information society, 27 (5).
References
External links
'Faces of Information', downloadable article about Professor Jannis Kallinikos in Mercury Magazine issue 1, 2012
'Faces of Information', article about Professor Jannis Kallinikos in Mercury Magazine issue 1, 2012
BBC radio interview at 'The Forum' with Professor Jannis Kallinikos, 08.10.2011
The 8th Social Study of ICT workshop (SSIT8) at LSE: "The Habitat of Information: Social and Organizational Consequences of Information Growth"
Summary at the London School of Economics website
Some of Jannis Kallinikos' articles on Telos think tank (in both French and English)
1954 births
Living people
People from Preveza
Academics of the London School of Economics
Academic staff of Uppsala University
Academic staff of the University of Bologna
Academic staff of Linnaeus University
Academic staff of Umeå University
Academic staff of the University of Macedonia
Stanford University faculty
Athens University of Economics and Business alumni
Uppsala University alumni
Information systems researchers | Jannis Kallinikos | Technology | 1,645 |
75,063,298 | https://en.wikipedia.org/wiki/List%20of%20earliest%20tools | The following table attempts to list the oldest-known Paleolithic and Paleo-Indian sites where hominin tools have been found. It includes sites where compelling evidence of hominin tool use has been found, even if no actual tools have been found.
Stone tools preserve more readily than tools of many other materials. So the oldest tools that we can find in many areas are going to be stone tools. It could be that these tools were once accompanied by, or even preceded by, non-stone tools that we cannot find because they did not preserve.
Similarly, hard materials like bone or shell are more likely than softer materials to leave discernible cut marks on bone. Bamboo has been shown to leave cut marks on bone that are harder to see than cut marks by stone. So the earliest evidence of tool use that we are likely to find are often cut marks made on bone by stone or shell tools.
Therefore the reader should not assume that the items on this list represent the earliest uses of tools in each area, but rather the earliest uses of tools that have been found.
Because it focuses on only the earliest evidence of tools, and since the earliest evidence is biased towards stone by stone's increased likelihood of preservation, this page necessarily omits mention of many significant ancient tools of non-stone materials simply because those cases are not among the earliest found within their geographic area. See Timeline of historic inventions for other noteworthy tools and other inventions.
With its focus on tools, this list also omits some sites with the earliest evidence for the existence of hominins, but without evidence for tools. Many such sites have hominin bones, teeth, or footprints, but unless they also include evidence for tools or tool use, they are omitted here.
This list excludes tools and tool use attributed to non-hominin species. See Tool use by non-humans.
Since there are far too many hominin tool sites to list on a single page, this page attempts to list the 6 or fewer top candidates for oldest tool site within each significant geographic area.
Geographic areas covered
Africa
East Africa
North Africa
Southern Africa
West Africa
Americas
North America
South America
Asia
East Asia
Island Southeast Asia - Islands between Sunda Shelf and Sahul, not connected to either one during the Last Glacial Maximum
South Asia
Sunda Shelf
West Asia
Europe
Eastern Europe
Western Europe
Sahul - Australia and New Guinea
Indian Ocean
For much of the 20th century, a "Clovis first" idea dominated American archeology. Many sites with dates too old to be compatible with "Clovis first" were published, but these were mostly dismissed under the hegemony of "Clovis first." Meanwhile some indigenous archeologists insisted throughout the "Clovis first" era that the peopling of the Americas was much older than Clovis. Recent publications with very strong evidence for pre-Clovis sites seem to have ended the hegemony of "Clovis first."
List of tools
See also
Hominini
List of human evolution fossils
Stone Age
Stone tool
Timeline of historic inventions
Tool use by non-humans
References
Tools
Hand tools
Archaeology-related lists
Archaeological sites | List of earliest tools | Engineering | 639 |
77,538,555 | https://en.wikipedia.org/wiki/NGC%206676 | NGC 6676 is a spiral galaxy in the constellation of Draco. Its velocity with respect to the cosmic microwave background is 6707 ± 12 km/s, which corresponds to a Hubble distance of 98.92 ± 6.93 Mpc (∼323 million light-years). It was discovered by American astronomer Lewis Swift on 30 May 1886.
One supernova has been observed in NGC 6676: SN 2023txu (type Ia, mag 18.96) was discovered by ATLAS on 3 October 2023.
See also
List of NGC objects (6001–7000)
References
External links
6676
11286
062021
Draco (constellation)
18860530
Discoveries by Lewis Swift
+11-22-054
Spiral galaxies
18331+6655 | NGC 6676 | Astronomy | 162 |
33,606,856 | https://en.wikipedia.org/wiki/Ford%208.8%20axle | The Ford 8.8 is an automotive axle manufactured by Ford Motor Company at the Sterling Axle Plant in Sterling Heights, MI. It was first used in model year 1983 Ford trucks. The axle was developed to replace the Ford 9-inch axle. This axle is still in production today for a variety of Ford vehicles.
General Specifications
Ring gear measures 8.8".
28 Spline axle shafts with a 1.29" diameter
31 Spline axle shafts with a 1.32" diameter
Ratios: 2.26, 2.47, 2.73, 3.08, 3.27, 3.31, 3.45, 3.55, 3.73, 4.10, 4.56 & 5.14
8.8 Solid Axle
Ford first used the 8.8 axle in 1983 model year trucks and is still in production for the Ford Ranger and Ford F-Series. It was also used in the Ford SUVs until Independent suspension replaced the solid axle. Ring, pinion and carrier all remained between the solid axle and independent rear suspension.
The solid rear axle from 1995-2001 Explorers is a popular swap for older Jeep Wranglers and Cherokees. In addition to being nearly the same width, they have the same wheel bolt pattern, are equipped with disc brakes, and are much stronger than the Dana 35 they replace.
It was also used in V8 equipped Mustangs from 1986 to the 2014 model years; and all Mustang models from 2011-2014.
Common Applications
Source:
1986-2014 Ford Mustang
1983-2014 Ford F-150
1983-1996 Ford Bronco
2001-2005 Ford Explorer Sport Trac
1991-2011 Ford Ranger 4.0L models
1991-2001 Ford Explorer (Solid axle)
1985-2011 Ford Panther platform vehicles
Super 8.8
Ford released an updated version in both solid and IRS form for 2015+ Mustangs and F-150. The most apparent difference is a 12 bolt cover instead of the traditional 10. The super 8.8 also uses larger bearings,longer pinion with larger nut, and most significantly 34 spline axles or half shafts. First Look: Ford Performance Super 8.8-inch Ring And Pinion For S550
8.8 Independent Rear Suspension
The 8.8 IRS first saw use in the 1989 model year Ford Thunderbird and later Ford adapted independent suspension to its 3rd generation Explorer and 2nd generation Expedition SUVs.
The Mustang first used the 8.8 IRS on 1999-2004 Cobra models. The IRS became standard across the Mustang line for the 2015 model year with the "super 8.8."
Applications
1988-1997 Ford Thunderbird
1999-2004 Ford Mustang Cobra
2003-2010 Ford Explorer
2003-2010 Mercury Mountaineer
2003-2005 Lincoln Aviator
2003-2006 Ford Expedition
2003-2006 Lincoln Navigator
8.8 Independent Front Suspension
The 8.8 IFS was first used in the 1997 model year Ford F-150 and Ford Expedition and has been in use ever since.
Applications
Source:
1997-2008 Ford F-150 (28-spline)
1997-2008 Ford F-250 (28-spline)
1997-2008 Ford Expedition (28-spline)
2008-2019 Ford F-150 (31-spline)
2008-2019 Ford Expedition (31-spline)
References
Automotive engineering
Automobile axles | Ford 8.8 axle | Engineering | 664 |
287,141 | https://en.wikipedia.org/wiki/Langdon%20Winner | Langdon Winner (born August 7, 1944) was Thomas Phelan Chair of Humanities and Social Sciences in the Department of Science and Technology Studies at Rensselaer Polytechnic Institute, Troy, New York.
Langdon Winner was born in San Luis Obispo, California on August 7, 1944. He received his B.A. in 1966, M.A. in 1967 and Ph.D. in 1973, all in political science at the University of California, Berkeley. His primary focus was political theory.
He has been a professor at Leiden, MIT, University of California, Los Angeles and at the University of California, Santa Cruz. Since 1985 he has been at the Rensselaer Polytechnic Institute; he was a visiting professor at Harvey Mudd College (2000) and Colgate University (2001). In 2010 he was a Fulbright Fellow visiting the Universidad Complutense in Madrid.
Winner lives in upstate New York. He is married to Gail P. Stuart and has three children. His interests include science, technology, American popular culture, and theories of sustainability.
Winner is known for his articles and books on science, technology, and society. He also spent several years as a reporter, rock music critic, and contributing editor for Rolling Stone magazine.
Technology and politics
In 1980 Winner proposed that technologies embody social relations, i.e. power. To the question he poses "Do Artifacts Have Politics?", Winner identifies two ways in which artifacts can have politics. The first, involving technical arrangements and social order, concerns how the invention, design, or arrangement of artifacts or the larger system becomes a mechanism for settling the affairs of a community. This way "transcends the simple categories of 'intended' and 'unintended' altogether", representing "instances in which the very process of technical development is so thoroughly biased in a particular direction that it regularly produces results heralded as wonderful breakthroughs by some social interests and crushing setbacks by others" (Winner, p. 25-6, 1999). It implies that the process of technological development is critical in determining the politics of an artifact; hence the importance of incorporating all stakeholders in it. (Determining who the stakeholders are and how to incorporate them are other questions entirely.)
The second way in which artifacts can have politics refers to artifacts that correlate with particular kinds of political relationships, which Winner refers to as inherently political artifacts (Winner, p. 22, 1999). He distinguishes between two types of inherently political artifacts: those that require a particular sociological system and those that are strongly compatible with a particular sociological system (Winner, p. 29, 1999). A further distinction is made between conditions internal to the workings of a given technical system and those that are external to it (Winner, p. 33, 1999). This second way in which artifacts can have politics can be further articulated as consisting of four 'types' of artifacts: those requiring a particular internal sociological system, those compatible with a particular internal sociological system, those requiring a particular external sociological system, and those compatible with a particular external sociological system.
Certain features of Winner's thesis have been criticized by other scholars, including Bernward Joerges.
Music
Winner contributed piano and backing vocals to the hoax album The Masked Marauders created by Rolling Stone. He also played piano on "Church Key" by The Revels. Winner is also notable for having written a negative review of one of the most critically acclaimed albums of the 1970's, Neil Young's After the Gold Rush.
Critique of educational technologies
Over the years one focus of Winner's criticism has been the excessive use of technologies in the classroom, both in K-12 schools and higher education. Winner's critique is well explained in his article "Information Technology and Educational Amnesia," and expressed in his satirical lecture, "The Automatic Professor Machine."
Selected articles
"Do Artifacts Have Politics?" in Daedalus, Vol. 109, No. 1, Winter 1980. Reprinted in The Social Shaping of Technology, edited by Donald A. MacKenzie and Judy Wajcman (London: Open University Press, 1985; second edition 1999). Also adapted in Winner's book The Whale and the Reactor: A Search for Limits in an Age of High Technology, University of Chicago Press, 1986.
"Engineering Ethics and Political Imagination," in Broad and Narrow Interpretations of Philosophy of Technology, edited by Paul T. Durbin (Dordrecht: Springer Netherlands, 1990), pp. 53–64.
"Social Constructivism: Opening the Black Box and Finding It Empty," Science as Culture, Vol. 3, Issue 3, 1993, pp. 427–452.
"How Technology Reweaves the Fabric of Society," The Chronicle of Higher Education, 39, Issue 48, August 4, 1993, pp. B1-B3.
"Sow's Ears from Silk Purses: The Strange Alchemy of Technological Visionaries," in Technological Visions: The Hopes and Fears that Shape New Technologies, edited by Marita Sturken, Douglas Thomas and Sandra J. Ball-Rokeach (Temple University Press, Philadelphia, 2004), pp. 34–47.
Selected books
Autonomous Technology: Technics-out-of-Control as a Theme in Political Thought, M.I.T. Press, 1977. ()
The Whale and the Reactor: A Search for Limits in an Age of High Technology, University of Chicago Press, 1986. ()
Technology and Democracy, (editor), Dordrecht and Boston: Reidel/Kluwer, 1992.
Technology and Democracy: Technology in the Public Sphere, co-edited with Andrew Feenberg and Torben Hviid Nielsen, Oslo: Center for Technology and Culture, 1997.
References
External links
Langdon Winner's homepage
Several articles by Langdon Winner at the Online Luddism Index
Langdon Winner's blog
Video: Dialogue between Langdon Winner and Yochai Benkler on The Wealth of Networks at Medialab-Prado (Madrid, Spain) on June 30, 2010.
Video: "Local citizens against global, corporate power" Talk at Medialab-Prado (Madrid, Spain) on June 8, 2011.
Audio: "New technologies and Real Democracy Now! Talk at La Casa Invisible (Málaga, Spain) on June 15, 2011.
on Spanish M15 movement (November, 2011).
Living people
Science and technology studies scholars
Neo-Luddites
UC Berkeley College of Letters and Science alumni
Rensselaer Polytechnic Institute faculty
American philosophers of technology
1944 births | Langdon Winner | Technology | 1,327 |
34,816,371 | https://en.wikipedia.org/wiki/Insect%20pheromone-binding%20protein | In molecular biology, the insect pheromone-binding family A10/OS-D is a family of small helical proteins postulated to contribute to the specificity of the insect’s olfactory system by binding components of the natural pheromone mixtures.
A class of small (14-20 Kd) water-soluble proteins, called pheromone binding proteins, first discovered in the insect sensillar lymph but also found in the mucus of vertebrates, is postulated to mediate the solubilisation of hydrophobic odorant molecules, and thereby to facilitate their transport to the receptor neurons. The product of a gene expressed in the olfactory system of Drosophila melanogaster (Fruit fly), OS-D, shares features common to vertebrate odorant binding proteins, but has a primary structure unlike odorant-binding proteins. OS-D derivatives have subsequently been found in chemosensory organs of phylogenetically distinct insects, including cockroaches, phasmids and moths, suggesting that OS-D-like proteins seem to be conserved in the insect phylum. OS-D and related proteins are members of the insect pheromone-binding family A10/OS-D.
References
Further reading
Protein families | Insect pheromone-binding protein | Biology | 269 |
11,336,666 | https://en.wikipedia.org/wiki/Evaluation%20of%20machine%20translation | Various methods for the evaluation for machine translation have been employed. This article focuses on the evaluation of the output of machine translation, rather than on performance or usability evaluation.
Round-trip translation
A typical way for lay people to assess machine translation quality is to translate from a source language to a target language and back to the source language with the same engine. Though intuitively this may seem like a good method of evaluation, it has been shown that round-trip translation is a "poor predictor of quality". The reason why it is such a poor predictor of quality is reasonably intuitive. A round-trip translation is not testing one system, but two systems: the language pair of the engine for translating into the target language, and the language pair translating back from the target language.
Consider the following examples of round-trip translation performed from English to Italian and Portuguese from Somers (2005):
{|
!Original text
| Select this link to look at our home page.
|-
!Translated
| Selezioni questo collegamento per guardare il nostro Home Page.
|-
!Translated back
| Selections this connection in order to watch our Home Page.
|}
{|
!Original text
| Tit for tat
|-
!Translated
| Melharuco para o tat
|-
!Translated back
| Tit for tat
|}
In the first example, where the text is translated into Italian then back into English—the English text is significantly garbled, but the Italian is a serviceable translation. In the second example, the text translated back into English is perfect, but the Portuguese translation is meaningless; the program thought "tit" was a reference to a tit (bird), which was intended for a "tat", a word it did not understand.
While round-trip translation may be useful to generate a "surplus of fun," the methodology is deficient for serious study of machine translation quality.
Human evaluation
This section covers two of the large scale evaluation studies that have had significant impact on the field—the ALPAC 1966 study and the ARPA study.
Automatic Language Processing Advisory Committee (ALPAC)
One of the constituent parts of the ALPAC report was a study comparing different levels of human translation with machine translation output, using human subjects as judges. The human judges were specially trained for the purpose. The evaluation study compared an MT system translating from Russian into English with human translators, on two variables.
The variables studied were "intelligibility" and "fidelity". Intelligibility was a measure of how "understandable" the sentence was, and was measured on a scale of 1–9. Fidelity was a measure of how much information the translated sentence retained compared to the original, and was measured on a scale of 0–9. Each point on the scale was associated with a textual description. For example, 3 on the intelligibility scale was described as "Generally unintelligible; it tends to read like nonsense but, with a considerable amount of reflection and study, one can at least hypothesize the idea intended by the sentence".
Intelligibility was measured without reference to the original, while fidelity was measured indirectly. The translated sentence was presented, and after reading it and absorbing the content, the original sentence was presented. The judges were asked to rate the original sentence on informativeness. So, the more informative the original sentence, the lower the quality of the translation.
The study showed that the variables were highly correlated when the human judgment was averaged per
sentence. The variation among raters was small, but the researchers recommended that at the very least, three or four raters should be used. The evaluation methodology managed to separate translations by humans from translations by machines with ease.
The study concluded that, "highly reliable assessments can be made of the quality of human and machine translations".
Advanced Research Projects Agency (ARPA)
As part of the Human Language Technologies Program, the Advanced Research Projects Agency (ARPA) created a methodology to evaluate machine translation systems, and continues to perform evaluations based on this methodology. The evaluation programme was instigated in 1991, and continues to this day. Details of the programme can be found in White et al. (1994) and White (1995).
The evaluation programme involved testing several systems based on different theoretical approaches; statistical,
rule-based and human-assisted. A number of methods for the evaluation of the output from these systems were tested in 1992 and the most recent suitable methods were selected for inclusion in the programmes for subsequent years. The methods were; comprehension evaluation, quality panel evaluation, and evaluation based on adequacy and fluency.
Comprehension evaluation aimed to directly compare systems based on the results from multiple choice comprehension tests, as in Church et al. (1993). The texts chosen were a set of articles in English on the subject of financial news. These articles were translated by professional translators into a series of language pairs, and then translated back into English using the machine translation systems. It was decided that this was not adequate for a standalone method of comparing systems and as such abandoned due to issues with the modification of meaning in the process of translating from English.
The idea of quality panel evaluation was to submit translations to a panel of expert native English speakers who were professional translators and get them to evaluate them. The evaluations were done on the basis of a metric, modelled on a standard US government metric used to rate human translations. This was good from the point of view that the metric was "externally motivated", since it was not specifically developed for machine translation. However, the quality panel evaluation was very difficult to set up logistically, as it necessitated having a number of experts together in one place for a week or more, and furthermore for them to reach consensus. This method was also abandoned.
Along with a modified form of the comprehension evaluation (re-styled as informativeness evaluation), the most
popular method was to obtain ratings from monolingual judges for segments of a document. The judges were presented with a segment, and asked to rate it for two variables, adequacy and fluency. Adequacy is a rating of how much information is transferred between the original and the translation, and fluency is a rating of how good the English is. This technique was found to cover the relevant parts of the quality panel evaluation, while at the same time being easier to deploy, as it didn't require expert judgment.
Measuring systems based on adequacy and fluency, along with informativeness is now the standard methodology for the
ARPA evaluation program.
Automatic evaluation
In the context of this article, a metric is a measurement. A metric that evaluates machine translation output represents the quality of the output. The quality of a translation is inherently subjective, there is no objective or quantifiable "good." Therefore, any metric must assign quality scores so they correlate with the human judgment of quality. That is, a metric should score highly translations that humans score highly, and give low scores to those humans give low scores. Human judgment is the benchmark for assessing automatic metrics, as humans are the end-users of any translation output.
The measure of evaluation for metrics is correlation with human judgment. This is generally done at two levels, at the sentence level, where scores are calculated by the metric for a set of translated sentences, and then correlated against human judgment for the same sentences. And at the corpus level, where scores over the sentences are aggregated for both human judgments and metric judgments, and these aggregate scores are then correlated. Figures for correlation at the sentence level are rarely reported, although Banerjee et al. (2005) do give correlation figures that show that, at least for their metric, sentence-level correlation is substantially worse than corpus level correlation.
While not widely reported, it has been noted that the genre, or domain, of a text has an effect on the correlation obtained when using metrics. Coughlin (2003) reports that comparing the candidate text against a single reference translation does not adversely affect the correlation of metrics when working in a restricted domain text.
Even if a metric correlates well with human judgment in one study on one corpus, this successful correlation may not carry over to another corpus. Good metric performance, across text types or domains, is important for the reusability of the metric. A metric that only works for text in a specific domain is useful, but less useful than one that works across many domains—because creating a new metric for every new evaluation or domain is undesirable.
Another important factor in the usefulness of an evaluation metric is to have a good correlation, even when working with small amounts of data, that is candidate sentences and reference translations. Turian et al. (2003) point out that, "Any MT evaluation measure is less reliable on shorter translations", and show that increasing the amount of data improves the reliability of a metric. However, they add that "... reliability on shorter texts, as short as one sentence or even one phrase, is highly desirable because a reliable MT evaluation measure can greatly accelerate exploratory data analysis".
Banerjee et al. (2005) highlight five attributes that a good automatic metric must possess; correlation, sensitivity, consistency, reliability and generality. Any good metric must correlate highly with human judgment, it must be consistent, giving similar results to the same MT system on similar text. It must be sensitive to differences between MT systems and reliable in that MT systems that score similarly should be expected to perform similarly. Finally, the metric must be general, that is it should work with different text domains, in a wide range of scenarios and MT tasks.
The aim of this subsection is to give an overview of the state of the art in automatic metrics for evaluating machine translation.
BLEU
BLEU was one of the first metrics to report a high correlation with human judgments of quality. The
metric is currently one of the most popular in the field. The central idea behind the metric is that "the closer a
machine translation is to a professional human translation, the better it is". The metric calculates scores for individual segments, generally sentences — then averages these scores over the whole corpus for a final score. It has been shown to correlate highly with human judgments of quality at the corpus level.
BLEU uses a modified form of precision to compare a candidate translation against multiple reference translations. The metric modifies simple precision since machine translation systems have been known to generate more words than appear in a reference text. No other machine translation metric is yet to significantly outperform BLEU with respect to correlation with human judgment across language pairs.
NIST
The NIST metric is based on the BLEU metric, but with some alterations. Where BLEU simply calculates n-gram precision adding equal weight to each one, NIST also calculates how informative a particular n-gram is. That is to say, when a correct n-gram is found, the rarer that n-gram is, the more weight it is given. For example, if the bigram "on the" correctly matches, it receives lower weight than the correct matching of bigram "interesting calculations," as this is less likely to occur. NIST also differs from BLEU in its calculation of the brevity penalty, insofar as small variations in translation length do not impact the overall score as much.
Word error rate
The Word error rate (WER) is a metric based on the Levenshtein distance, where the Levenshtein distance works at the character level, WER works at the word level. It was originally used for measuring the performance of speech recognition systems but is also used in the evaluation of machine translation. The metric is based on the calculation of the number of words that differ between a piece of machine-translated text and a reference translation.
A related metric is the Position-independent word error rate (PER), which allows for the re-ordering of words and sequences of words between a translated text and a reference translation.
METEOR
The METEOR metric is designed to address some of the deficiencies inherent in the BLEU metric. The metric is based on the weighted harmonic mean of unigram precision and unigram recall. The metric was designed after research by Lavie (2004) into the significance of recall in evaluation metrics. Their research showed that metrics based on recall consistently achieved higher correlation than those based on precision alone, cf. BLEU and NIST.
METEOR also includes some other features not found in other metrics, such as synonymy matching, where instead of matching only on the exact word form, the metric also matches on synonyms. For example, the word "good" in the reference rendering as "well" in the translation counts as a match. The metric is also includes a stemmer, which lemmatises words and matches on the lemmatised forms. The implementation of the metric is modular insofar as the algorithms that match words are implemented as modules, and new modules that implement different matching strategies may easily be added.
LEPOR
A new MT evaluation metric LEPOR was proposed as the combination of many evaluation factors including existing ones (precision, recall) and modified ones (sentence-length penalty and n-gram based word order penalty). The experiments were tested on eight language pairs from ACL-WMT2011 including English-to-other (Spanish, French, German, and Czech) and the inverse, and showed that LEPOR yielded higher system-level correlation with human judgments than several existing metrics such as BLEU, Meteor-1.3, TER, AMBER and MP4IBM1. An enhanced version of LEPOR metric, hLEPOR, is introduced in the paper. hLEPOR utilizes the harmonic mean to combine the sub-factors of the designed metric. Furthermore, they design a set of parameters to tune the weights of the sub-factors according to different language pairs. The ACL-WMT13 Metrics shared task results show that hLEPOR yields the highest Pearson correlation score with human judgment on the English-to-Russian language pair, in addition to the highest average-score on five language pairs (English-to-German, French, Spanish, Czech, Russian). The detailed results of WMT13 Metrics Task is introduced in the paper.
Overviews on Human and Automatic Evaluation Methodologies
There are some machine translation evaluation survey works, where people introduced more details about what kinds of human evaluation methods they used and how they work, such as the intelligibility, fidelity, fluency, adequacy, comprehension, and informativeness, etc. For automatic evaluations, they also did some clear classifications such as the lexical similarity methods, the linguistic features application, and the subfields of these two aspects. For instance, for lexical similarity, it contains edit distance, precision, recall and word order; for linguistic feature, it is divided into the syntactic feature and the semantic feature respectively. Some state-of-the-art overview on both manual and automatic translation evaluation introduced the recently developed translation quality assessment (TQA) methodologies, such as the crowd-sourced intelligence Amazon Mechanical Turk utilization, statistical significance testing, re-visiting traditional criteria with newly designed strategies, as well as MT quality estimation (QE) shared tasks from the annual workshop on MT (WMT) and corresponding models that do not rely on human offered reference translations.
See also
Comparison of machine translation applications
Machine translation software usability
Notes
References
Banerjee, S. and Lavie, A. (2005) "METEOR: An Automatic Metric for MT Evaluation with Improved Correlation with Human Judgments" in Proceedings of Workshop on Intrinsic and Extrinsic Evaluation Measures for MT and/or Summarization at the 43rd Annual Meeting of the Association of Computational Linguistics (ACL-2005), Ann Arbor, Michigan, June 2005
Church, K. and Hovy, E. (1993) "Good Applications for Crummy Machine Translation". Machine Translation, 8 pp. 239–258
Coughlin, D. (2003) "Correlating Automated and Human Assessments of Machine Translation Quality" in MT Summit IX, New Orleans, USA pp. 23–27
Doddington, G. (2002) "Automatic evaluation of machine translation quality using n-gram cooccurrence statistics". Proceedings of the Human Language Technology Conference (HLT), San Diego, CA pp. 128–132
Gaspari, F. (2006) "Look Who's Translating. Impersonations, Chinese Whispers and Fun with Machine Translation on the Internet" in Proceedings of the 11th Annual Conference of the European Association of Machine Translation
Graham, Y. and T. Baldwin. (2014) "Testing for Significance of Increased Correlation with Human Judgment". Proceedings of EMNLP 2014, Doha, Qatar
Lavie, A., Sagae, K. and Jayaraman, S. (2004) "The Significance of Recall in Automatic Metrics for MT Evaluation" in Proceedings of AMTA 2004, Washington DC. September 2004
Papineni, K., Roukos, S., Ward, T., and Zhu, W. J. (2002). "BLEU: a method for automatic evaluation of machine translation" in ACL-2002: 40th Annual meeting of the Association for Computational Linguistics pp. 311–318
Somers, H. (2005) "Round-trip Translation: What Is It Good For?"
Somers, H., Gaspari, F. and Ana Niño (2006) "Detecting Inappropriate Use of Free Online Machine Translation by Language Students - A Special Case of Plagiarism Detection". Proceedings of the 11th Annual Conference of the European Association of Machine Translation, Oslo University (Norway) pp. 41–48
ALPAC (1966) "Languages and machines: computers in translation and linguistics". A report by the Automatic Language Processing Advisory Committee, Division of Behavioral Sciences, National Academy of Sciences, National Research Council. Washington, D.C.: National Academy of Sciences, National Research Council, 1966. (Publication 1416.)
Turian, J., Shen, L. and Melamed, I. D. (2003) "Evaluation of Machine Translation and its Evaluation". Proceedings of the MT Summit IX, New Orleans, USA, 2003 pp. 386–393
White, J., O'Connell, T. and O'Mara, F. (1994) "The ARPA MT Evaluation Methodologies: Evolution, Lessons, and Future Approaches". Proceedings of the 1st Conference of the Association for Machine Translation in the Americas. Columbia, MD pp. 193–205
White, J. (1995) "Approaches to Black Box MT Evaluation". Proceedings of MT Summit V
Han, A.L.F., Wong, D.F., and Chao, L.S. (2012) "LEPOR: A Robust Evaluation Metric for Machine Translation with Augmented Factors" in Proceedings of the 24th International Conference on Computational Linguistics (COLING 2012): Posters, Mumbai, India. Open source tool pp. 441–450
Han, A.L.F., Wong, D.F., Chao, L.S., He, L., Lu, Y., Xing, J., and Zeng, X. (2013a) "Language-independent Model for Machine Translation Evaluation with Reinforced Factors" in Proceedings of the Machine Translation Summit XIV, Nice, France. International Association for Machine Translation. Open source tool
ACL-WMT. (2013) "ACL-WMT13 METRICS TASK"
Han, A.L.F., Wong, D.F., Chao, L.S., Lu, Y., He, L., Wang, Y., and Zhou, J. (2013b) "A Description of Tunable Machine Translation Evaluation Systems in WMT13 Metrics Task" in Proceedings of the Eighth Workshop on Statistical Machine Translation, ACL-WMT13, Sofia, Bulgaria. Association for Computational Linguistics. Online paper pp. 414–421
Han, Lifeng (2016) "Machine Translation Evaluation Resources and Methods: A Survey" in arXiv:1605.04515 [cs.CL], pp. 1–14, May, 2016.
EuroMatrix. 2007. 1.3: Survey of Machine Translation Evaluation. Public Distribution. Project funded by the European Community under the Sixth Framework Programme for Research and Technological Development.
Bonnie Dorr, Matt Snover, Nitin Madnani . Part 5: Machine Translation Evaluation. Editor: Bonnie Dorr. Book chapter.
Han, Lifeng, Jones, Gareth and Smeaton, Alan (2021) Translation quality assessment: a brief survey on manual and automatic methods. In: MoTra21: Workshop on Modelling Translation: Translatology in the Digital Age, @NoDaLiDa 2021. 19 pages. Publisher: Association for Computational Linguistics.
Further reading
Machine Translation Archive: Subject Index : Publications after 2000 (see Evaluation subheading)
Machine Translation Archive: Subject Index : Publications prior to 2000 (see Evaluation subheading)
Machine Translation Evaluation: A Survey : Publications up to 2015
Software for Automated Evaluation
Asia Online Language Studio - Supports BLEU, TER, F-Measure, METEOR
BLEU
F-Measure
NIST
METEOR
TER
TERP
LEPOR
hLEPOR
KantanAnalytics - segment level MT quality estimation
Machine translation | Evaluation of machine translation | Technology | 4,409 |
4,189,764 | https://en.wikipedia.org/wiki/Richard%20Soley | Richard Mark Soley (born c. 1960, in Baltimore, Maryland, died 8 Nov., 2023, in Lexington, Massachusetts) was an American computer scientist and businessman, and chairman and CEO of the Object Management Group, Inc. (OMG). He was also the executive director of the Cloud Standards Customer Council, and executive director of the Industrial Internet Consortium, managed by the OMG.
Life and work
Soley studied Computer Science and Engineering at the Massachusetts Institute of Technology, where he obtained his S.B. in 1982, his S.M. in 1985 and his Ph.D. in 1989. He began his professional life at Honeywell, working on the Multics operating system.
Soley joined OMG as Technical Director in 1989, leading the development of OMG's standardization process and the original CORBA specification.
In 1996, he led the effort to move into vertical market standards (starting with healthcare, finance, telecommunications and manufacturing) and modeling. Those efforts made OMG a major early adopter of Unified Modeling Language (UML) and model-driven architecture (MDA).
Soley was co-founder, former chairman, and CEO of A.I. Architects, Inc., a firm which manufactured hardware and software for personal computers and workstations. He has also served as a consultant on matters relating to software investment opportunities for several corporations including IBM, Motorola, and Texas Instruments.
He also played a very significant role within the SEMAT initiative, launched in December 2009.
Selected publications
Soley, Richard Mark. Object Management Architecture Guide: Revision 2.0. Wiley, 1995.
References
External links
Richard Mark Soley personal website
Living people
Year of birth uncertain
American computer scientists
Businesspeople from Baltimore
Stanford University School of Engineering alumni
Multics people
Year of birth missing (living people) | Richard Soley | Technology | 370 |
37,250,670 | https://en.wikipedia.org/wiki/Coccomyces%20dentatus | Coccomyces dentatus is a species of fungus in the family Rhytismataceae. A widespread species, particularly in temperate areas, it colonizes the dead fallen leaves of vascular plants, particularly oak and chestnut. The fungus apothecia, which form in the epidermal layer of the leaf host, resemble dark hexagonal spots scattered on a multi-colored mosaic pattern bounded by thin black lines. When mature, the apothecia open by triangular flaps to release spores. The anamorph form of C. dentatus is Tricladiopsis flagelliformis. Lookalike species can be distinguished by the shape of the apothecia, or by microscopic characteristics.
Taxonomy
The species was first described scientifically as Phacidium dentatum by Johann Karl Schmidt in 1817. Italian botanist Giuseppe De Notaris moved it to Lophodermium in 1847. In 1877, Pier Andrea Saccardo transferred it to Coccomyces, giving it its current name. The variety C. dentatus var. hexagonus, described by Otto Penzig and Saccardo from West Java, Indonesia in 1901, is sometimes applied to western US collections with large six-sided apothecia. However, its status is unclear, as the type is no longer in Saccardo's herbarium at the University of Padua, and Penzig's collection was destroyed during World War II. C. dentatus f. lauri was described by Heinrich Rehm in 1901, for a collection found growing on a species of Lauraceae in Rio Grande do Sul (southern Brazil). According to English botanist Martha Sherwood, who revised the genus Coccomyces in 1980, it is indistinguishable from the main type and should be considered synonymous.
One author regarded C. dentatus as a synonym of Coccomyces coronatus, although later authors have treated them separately. In 1923, Carlos Luigi Spegazzini tentatively reported the presence of C. dentatus on fallen Nothofagus leaves in Tierra del Fuego (southern South America); this species was later identified as a distinct species, C. australis.
In 1982, Enrique Descals described an aquatic hyphomycete Tricladiopsis flagelliformis growing from submerged leaves found in the shoreline of Windermere (Cumbria, England), which he tentatively assigned as the anamorph state of Coccomyces dentatus. The specific epithet flagelliformis (from the Latin flagellum "whip" and forma "shape") refers to the "whip-like" form of the conidium.
Description
The apothecia of Coccomyces dentatus are distributed in bleached spots that are bounded by a black lines inside the outer cell layer of the leaf (intraepidermal). The black lines—often referred to as zone lines—are the result of an antagonistic interactions between individuals of different genotypes that colonize the leaf surface. Apothecia are usually accompanied by pycnidia (asexual fruit bodies) measuring 0.5–1.0 mm in diameter. The apothecia are black, and shiny, with four to six sides. They have a star-shaped pattern of grooves formed by lighter colored cells. When the spores are mature, these open (dehisce) by triangular "teeth" to expose the dull yellow hymenium (spore-bearing surface).
The layer covering the apothecia is about 30 μm thick, and made of blackened (carbonized) cells measuring 5–6 μm in diameter. At the base of the apothecia is carbonized supportive tissue about 5 μm thick. The paraphyses (sterile filamentous hyphal cells) are unbranched, threadlike (filiform), gradually enlarge to a width of 2.0 μm at the tip, and have granular contents. The thin-walled cylindrical to club-shaped asci (spore-bearing cells) are on a short stalk, and measure 70–105 by 8–10 μm; each ascus contains eight ascospores. Ascospores, which measure 45–65 by 3.0 μm, have a thin but distinct sheath, and lack septa (cross-walls). Pycnidia (which appear before the apothecia mature) are intraepidermal, lenticular (having the shape of a double-convex lens) in cross section, 0.1–0.3 mm in diameter, and covered with a dark brown layer of cells. The phialides are arranged in a basal layer, and borne on short conidiophores. They are slender and subulate (tapering to a point), lack a collarette, and measure 5–10 by 2–2.5 μm. The conidia are colorless, rod-shaped, lack septa, and have dimensions of 4–5 by 1.0 μm.
The putative anamorph form of C. dentatus has been described as Tricladiopsis flagelliformis. Grown on 2% malt agar at standard conditions, it forms black-centered colonies that have a growth rate of 7 cm per week. The conidia produced are thin and curved with a whip-like shape. They have 13–20 septa, measure 65–135 by 2–3.5 μm, and usually have a single branch (typically about 45 μm long) that appears before cells are released.
There are only a few species of Rhytismatales known to have anamorphs that do not function as spermatia (non-motile cells that function as a male gamete). Coccomyces dentatus is one of only two species that are known to have both a spermatial and a non-spermatial state (the other is Ascodichaena rugosa).
Similar species
The species is frequently confused with Coccomyces coronatus, which has inflated paraphyses, longer asci and ascospores, less regularly shaped apothecia, and rarely occurs on leaves of evergreens. It prefers to grow on well-rotted leaves, and is found predominantly in northern Europe and eastern North America. C. tumidus is somewhat similar in appearance, but distinguished in the field by round to ellipsoid apothecia. C. australis has circinate (rolled up with the tip in the center) rather than filiform paraphyses, larger asci and somewhat larger ascospores (150–180 by 14–16.5 μm and 60–75 by 2.5–3 μm, respectively). Another lookalike species that is morphological quite similar to C. dentatus is C. kinabaluensis, found in the Malaysian state of Sabah. However, the latter can be distinguished by the following characters: three- to four-sided ascocarps; ascospores with a single septum; and longer, wider asci measuring 110–135 by 10–14 μm.
Habitat and distribution
Coccomyces dentatus is a saprobic species, and grows on dead leaves of a wide variety of angiosperms. It is frequently encountered on members of the heather (family Ericaceae), and the beech family (Fagaceae), such as oak (red, white, and live oak) and chestnut, and also on the Castanea sativa from Chile. Other common substrates include leaves of trees in the genera Rhododendron, Lithocarpus, Berberis, Arbutus, Gaultheria, and Myrica.
Widely distributed and common, the fungus occurs predominantly in warm temperate areas. It has been found in Africa (Tunisia), Europe, and the Americas. In the northern part of its range, it occurs in the summer and autumn, but in subtropical areas it can be found year-round. Because of its wide geographical distribution, abundance, and conspicuousness, Coccomyces dentatus is the most often collected species of Coccomyces.
References
External links
Leotiomycetes
Fungi described in 1817
Fungi of Asia
Fungi of Central America
Fungi of Europe
Fungi of North America
Fungi of South America
Taxa named by Otto Kuntze
Fungus species | Coccomyces dentatus | Biology | 1,735 |
51,893,792 | https://en.wikipedia.org/wiki/Bierrum | Bierrum is a British civil engineering and construction company, that has built all of Britain's concrete cooling towers at the country's power stations since 1965.
History
Bierrum was founded by Hans Bierrum (or Hans Bjerrum), a Danish civil engineer that was born in Hellerup and had competed in the 1920 Summer Olympics in Belgium. Upon its establishment on 26 September 1927, the company was based at Victoria Street in London. Its first contract was at the former Shoreham Power Station; the first cooling tower was built in 1931. Bierrum became a limited company in 1938, and relocated to Harrow, then Sudbury Hill. Bierrum and Partners Ltd (00339806) was founded on 30 April 1938.
Hans Bjerrum passed away during 1979. Five years earlier, Hans' son, Roger, had been appointed as chairman of Bierrum. During 1991, the company acquired rival firm Pendrich out of receivership, rescuing 30 jobs in the process.
Throughout the 1990s and early 2000s, Bierrum introduced numerous means of improving safety for working at heights, including the Spider platform for the demolition of tall chimneys.
In September 2003, the company ran out of money, its fiscal circumstances having been troubled by a downturn in the power sector, legal action, and difficulties related to a project in Turkey. One year later, it was reformed as Bierrum International, through employees Gary Eastman and Bob Sutton. It became part of Beroa Technology Group GmbH (BTG) of Ratingen-Lintorf, North Rhine-Westphalia, Germany.
Presently, the company is named Dominion Bierrum and has been owned by Global Dominion Access of Bilbao since 2014, which was owned by CIE Automotive.
Structure
From January 1957, the company was headquartered at 167 Imperial Drive in Rayners Lane, an office building which it built for its own use. The company depot was at Smallford in Hertfordshire.
In 1981, Bierrum was based at Barwythe Hall at Studham near Dunstable.
It is headquartered in Central Bedfordshire, around one mile east of the M1, close to the Greensand Ridge Walk.
Projects
Bierrum has designed and built cooling towers (køletårn in Danish) and chimneys nationally and internationally. The firm demolishes chimneys incrementally using its Bierrum Rig.
Bierrum also built cement works, such as Ketton Cement Works in 1961, water towers, such as at North Walsham in 1954, and oil refinery chimneys.
In 1972, the firm built the 850 ft chimney of Grain Power Station, the tallest freestanding structure in South East England, completed in March 1975, requiring 38,100 tonnes of reinforcing steel and concrete.
Spinnaker Tower in Portsmouth, built by slip forming and climbing formwork (jumpform); the company ran out of money during construction in September 2003.
In 2016, it removed and rebuilt the iconic four chimneys of Battersea Power Station, in conjunction with contractor Skanska, and consultant engineer Buro Happold
Incidents
On the afternoon of Saturday 16 November 1958, 34 year old Edward Charles Burgess, of Goldenhill Rd in Fenton, fell 60 ft at Drakelow Power Station, and died on the morning of Sunday 17 November at Burton General Hospital
When building the Associated Portland Cement works at Westbury, Wiltshire in 1962, 22 year old steel erector, Winston Toms, fell 85 ft to his death
In April 1968, 55 year old Roman Mitchell, of Windsmoor St in Stoke, fell 40 ft to his death on the Rugeley B Power Station cooling tower number 8
See also
J. L. Eve Construction, built other UK electricity transmission infrastructure
Denmark–United Kingdom relations
Arup Group
Institute of Demolition Engineers, based in Kent
:Category:Construction and civil engineering companies of Denmark
References
External links
Science Museum
British companies established in 1938
Central Bedfordshire District
Chimneys in the United Kingdom
Companies based in Bedfordshire
Companies based in the London Borough of Harrow
Construction and civil engineering companies of the United Kingdom
Cooling towers
Demolition
Denmark–United Kingdom relations
1938 establishments in England
Construction and civil engineering companies established in 1938 | Bierrum | Engineering | 834 |
50,903,228 | https://en.wikipedia.org/wiki/ParkShuttle | The ParkShuttle is an electrically-driven, autonomous shuttle service that runs between Kralingse Zoom metro station in Rotterdam to the Rivium business park in Capelle aan den IJssel. The system first opened 1999 and has been extended since. It has three stops in Rivium (at the 4th, 2nd and 1st streets), a stop Fascinatio (serving the residential area in Capelle aan den IJssel and the Brainpark III business park) and finally at Kralingse Zoom metro station. In 2022 six vehicles of the third generation entered service.
Parkshuttle is owned by the Rotterdam-The Hague metropolitan area (MRDH) and operated by the Connexxion bus company. The route lies on its own right-of-way, but it does have level crossings with cars, cyclists and pedestrians. It is double-lane throughout except for a bridge over the N210 "Abraham van Rijckevorselweg" highway and an underpass below the A16 motorway to connect to the railway station.
On weekdays, the Shuttle runs between 06:00 and 21:00. During rush hour a shuttle runs every 2.5 minutes. Outside rush hours, the shuttle runs on demand with passengers pressing a button at the station to summon a vehicle.
In 2018 it was unique as the only operational automated road vehicle in Europe in permanent (revenue generating) service. Since 2015 a number of similar shared autonomous vehicle systems have been developed and trialed in routes shared with other vehicles or pedestrians. The ParkShuttle was trialed in 2019 at both Brussels Airport and at Nanyang Technological University in Singapore. Some other systems are in operation on private roads (such as around factories). some revenue systems are being trialed.
Features
The system, a hybrid between a personal rapid transit and an automated people mover, works like a horizontal elevator. A shuttle can be manually called at the stop, and there are buttons in the shuttle to request each stop individually (compared to a regular bus service, where stops must be requested at the appropriate time and location).
, the route is long and uses six shuttle vehicles numbered 1 through 6 (administratively numbered 5801 to 5806).
The vehicles are fully automatic and follow a virtual route where their positions are checked based on artificial reference points (in the form of small magnets in the road surface). They stop at fixed positions at the stations, most of which can fit two shuttles, one behind another. They were originally uni-directional (with front-wheel steering) and reversed direction at turning loops at both ends of the route, though they can also go in reverse as of Generation III. There is an automatic charging station at the Kralingse Zoom metro station where the batteries of the shuttles are charged every day.
The shuttles are designated as line 500 in timetables, but this is not indicated on the shuttles. The service was free of charge to use until the end of 2011, due to the lack of ticket machines and validators (later replaced by OV-chipcard readers) along with supervisors. Since the end of 2011, OV-chipcard readers are installed at the stops and no paper tickets are sold. As OV-chipcards can only be bought at the metro station proper (not the shuttle stop), passengers must have an OV chipcard on hand when boarding at other stops.
Experimental phase
An experimental phase started in 1997 with a vehicle that drove without any passengers for the first three months. The next three months test passengers rode the vehicle and crossing traffic was simulated. During the experimental phase a steward was in the vehicle. Eventually regular passengers were able to use the vehicle and the steward was no longer needed in the vehicle.
Generation I
The first version of the Parkshuttle ran from February 1999 to 2001 between Rotterdam and Capelle aan den IJssel. An evaluation showed that the new vehicle needed to be able to move more passengers and the waiting time had to be reduced. Furthermore, there was a need for a reliable system and better travel information.
Generation II
For ParkShuttle II the route was extended and became dual lane. New vehicles were introduced with more transport capacity: ParkShuttle II can carry a maximum of 22 passengers. The system and the vehicles were supplied by 2getthere, where Spijkstaal supplied the chassis and drive system and the design was made by Duvedec.
On 1 December 2006 ParkShuttle II was officially inaugurated by Prime Minister Jan Peter Balkenende. A day later the ParkShuttle was open to the public. Prior to that, concessionaire Connexxion had been granted a concession for the period 2006-2011. In 2011, after a new tender, the concession for a further period of 5 years was awarded to Connexxion. In 2016 the concession was extended by 2 years until December 2018.
Shortly after the system was put into operation, a collision occurred between two vehicles (without a driver) during start-up. The analysis of the incident showed that, after loss of communication at start-up of the system and after removal of the vehicle, an error was made by the supervisor as a result of which two other vehicles were allowed to enter the single lane section from different sides. The obstacle detection system did react, but could not prevent the collision. In addition, one vehicle was damaged by a fire in the storage of the vehicles.
After repairing the vehicles, the ParkShuttle has been running without any significant problems ever since.
During the period of April 2011 to December 2011, the system was out of service due to the construction of a parking garage at the Kralingse Zoom station. The ParkShuttle could not be used because the lane was blocked. A replacement bus service was used during this period. This bus service also runs in case of emergencies and drives on a lane next to the ParkShuttle.
The Metropolitan region Rotterdam-The Hague and the municipality of Capelle aan den IJssel undertook major maintenance on the existing ParkShuttle lane at the beginning of 2017.
Generation III
On 7 March 2018 the MRDH granted Connexxion a new concession for 15 years, for the period December 2018 to December 2033.
This concession includes an extension of the route, renewal of the fleet of shuttles and driving in mixed traffic on some parts of the route. The supplier of the system is again 2getthere, who has worked together with the municipality of Capelle aan den IJssel for this purpose. Together they have submitted a proposal for the replacement and extension with the Marketplace for Infrastructure of the 'Verkeersonderneming', which was granted early 2017. With this, the 'Verkeersonderneming' is responsible for 50% of the costs of realization.
In 2019 the vehicles were due to be replaced and the route extended to the Nieuwe Maas waterway, where passengers can change to the Waterbus at the Van Brienenoordbrug stop. In November 2022, after some delays due to the COVID-19 pandemic, the new third generation shuttles went into operation. The new vehicles are lighter than before, have air-conditioning and can drive in two directions which means the turning loops at the termini are no longer needed.
It is foreseen to extend the existing route towards the waterfront where a stop for the Waterbus will be created. On the extended route, the ParkShuttle will autonomously drive on the public road in mixed traffic.
See also
Personal Rapid Transit
Vehicular automation#Shared autonomous vehicles
References
External links
Vehicle specifications, see 2getthere
Information ParkShuttle on Connexxion website
first autonomous system, Capelle aan den IJssel
Concession awarded for further period of 5 years
Self-driving cars | ParkShuttle | Engineering | 1,593 |
13,205,506 | https://en.wikipedia.org/wiki/Grease%20ice | Grease ice is a very thin, soupy layer of frazil crystals clumped together, and only formed in large, open bodies of water most notably the ocean. Grease ice makes the water resemble an oil slick, the small crystals of ice held closely together reflect and refract light similarly to how oil will on water. Grease ice is the second stage in the formation of ice floes being the stage immediately following the frazil ice stage. Outside the ocean and seas, the Laurentian Great Lakes and Lake Baikal also form grease ice.
New sea ice formation takes place throughout the winter in the Arctic, and Antarctic where frazil forms and coalesces in polynyas or in cold-exposed regions of the open-ocean. Similarly, in seas and lakes, where latent energy is sufficient (waves, swells, fetch, tides, seiche, etc), turbulence mixes the frazil ice down into the upper layer and forms a surface layer of grease ice.
The term ‘grease ice’ follows World Meteorological Organization nomenclature. Grease ice differs from ‘slush’, where slush is similarly created by snow falling into the top layer of an ocean basin, river, or lake. The two terms are related due to the process of ice crystals being blown into a polynya, lake, ocean, or sea which can be the initiation of the grease ice layer, given a minimum level of mixing and cooling on the ocean surface.
Formation
When the water surface begins to lose heat rapidly, the water becomes supercooled. Turbulence, caused by strong winds or flow from a river, will mix the supercooled water throughout its entire depth. The supercooled water will already be encouraging the formation of small ice crystals (frazil ice) and the crystals will be mixed into the upper layer and form a surface layer.
Sea ice growth in turbulent water differs from sea ice growth in calm water. In turbulent water, the ice crystals accumulate at the surface, forming a grease-ice layer composed of individual ice crystals and small irregular clumps of ice crystals. In calm water conditions, nilas, a thin, almost invisible elastic crust, forms at the surface as water molecules freeze to the ice-water interface.
References
Sea ice
Snow or ice weather phenomena | Grease ice | Physics | 466 |
3,198,327 | https://en.wikipedia.org/wiki/Metadata%20management | Metadata management involves managing metadata about other data, whereby this "other data" is generally referred to as content data. The term is used most often in relation to digital media, but older forms of metadata are catalogs, dictionaries, and taxonomies. For example, the Dewey Decimal Classification is a metadata management system developed in 1876 for libraries.
Metadata schema
Metadata management goes by the end-to-end process and governance framework for creating, controlling, enhancing, attributing, defining and managing a metadata schema, model or other structured aggregation system, either independently or within a repository and the associated supporting processes (often to enable the management of content). For web-based systems, URLs, images, video etc. may be referenced from a triples table of object, attribute and value.
Scope
With specific knowledge domains, the boundaries of the metadata for each must be managed, since a general ontology is not useful to experts in one field whose language is knowledge-domain specific.
Metadata Manager
In the process of developing a knowledge management solution, creating a metadata schema, and a system in which metadata is managed, a dedicated resource may be appointed to maintain adherence to metadata standards as defined by data owners as well as general best practice. This person is responsible for curation of the business and technical layers of the metadata schema, and commonly involved with strategy and implementation. A metadata manager is not required to master all aspects, or be involved with everything concerning the solution, but an understanding of as much of the process as possible to ensure a relevant schema is developed.
Metadata management over time
Managing the metadata in a knowledge management solution is an important step in a metadata strategy. It is part of the strategy to make sure that the metadata are complete, current and correct at any given time. Managing a metadata project is also about making sure that users of the system are aware of the possibilities allowed by a well-designed metadata system and how to maximize the benefits of metadata. Regularly monitoring the metadata to ensure that the schema remains relevant is advised.
Wikipedia metadata
Wikipedia is a project that actively manages metadata for its articles and files. For example, volunteer editors carefully curate new biographical articles based on the notability (claim to fame), name, birth, and/or death dates. Similarly, volunteer editors carefully curate new architectural articles based on name, municipality, or geo coordinates. When new articles with a valid alternate spelling are added to Wikipedia that match up to existing articles based on metadata, these are then manually checked and if needed, tagged for merging. When new articles are added that are considered out of scope or otherwise unfit for Wikipedia, these are nominated for deletion. To help keep track of metadata on Wikipedia, the new Wikimedia project Wikidata was established in 2012. Click on the pictures to view more metadata about these images:
See also
Data defined storage
Metadata discovery
Metadata publishing
Metadata registry
ISO/IEC 11179
Dublin core
References
Metadata
Data management | Metadata management | Technology | 604 |
11,288,968 | https://en.wikipedia.org/wiki/GMP%20reductase | GMP reductase (Guanosine 5'-monophosphate oxidoreductase ) is an enzyme that catalyzes the irreversible and NADPH-dependent reductive deamination of GMP into IMP.
NADPH + guanosine 5-phosphate = NADP+ + inosine 5-phosphate + NH3
By converting guanosine nucleotides to inosine nucleotides, which serve as precursors to both adenosine (A) and G nucleotides, it helps maintains intracellular balance of A and G nucleotides. GMP can be broken down (catabolized) by other enzymes, but GMPR catalyzes the only recognized route for converting GMP to AMP (indirectly, through the IMP intermediate). Whereas the conversion of GMP to IMP involves a single enzyme, GMPR, the conversion of IMP to GMP involves two enzymes. First, inosine monophosphate dehydrogenase (IMPDH) catalyzes the conversion of IMP to XMP; then GMP synthetase (GMPS) catalyzes the conversion of XMP to GMP. These two pathways are inversely regulated, with conditions favoring IMPDH expression decreasing GMPR expression. In melanocytic cells, GMP reductase gene expression may be regulated by MITF. It is activated by GTP and inhibited by xanthosine 5'-monophosphate (XMP).
The amino acid sequence that makes up the GMP reductase is similar across organisms. In humans, there are hGMPR1 and hGMPR2, 2 GMP reductases that are different in their amino acid sequence (90% of the sequence is conserved) but has the same function overall. Although hGMPR1 and hGMPR2 do not have an identical amino acid sequence, they have similar kinetic properties and they both use NADPH as a coenzyme for their catalyzed reaction. Aside from human erythrocytes, GMPR has been isolated from E.coli as well as rodents.
Structure and catalytic mechanism
A crystal structure of hGMPR2 was obtained, and the model shows that hGMPR2 is a homotetramer that consist of a mix of alpha helices and beta sheets (parallel and antiparallel). Each monomer interacts with each other at their edges, which allow for stabilization of the tetramer structure. On the surface of each monomer, there are phosphate molecules that exist without any interactions with other subunits. The monomers are listed as monomer A, B, C and D. Monomers A and B consist of 338 residues, one GMP and two sulfate ions. Monomer C is similar, consisting of 327 residues, one GMP molecule and two sulfate ions. Monomer D, however, does not contain a GMP molecule and only consist of 317 residues and two sulfate ions. The alpha helices and beta sheets comes together to form a 8-stranded barrel core, in which it contains several hydrophobic residues that allow the stabilization of the core. The structure also contains disulfide bonds between Cys68 and Cys95, which are not conserved in most GMPRs, but is proposed to be important for stabilizing the entire tetramer structure.
The overall reaction consists of two steps: a deamination step, in which ammonia is released from guanosine and a covalent enzyme-GXP (E-XMP*) intermediate is formed, followed by a hydride transfer step, in which E-XMP* is reduced with a hydride from NADPH, releasing IMP. Inosine monophosphate dehydrogenase (IMPDH) and GMPR have similar catalytic mechanisms but different structural dynamics.
Species distribution
The rat version of GMPR is expressed in brown adipose tissue (BAT) when certain conditions triggers its response and it is mainly present in the kidney, as well as cardiac and skeletal muscle. One of these conditions include cold stimulation. When the organism is exposed to the cold, the GMPR RNA expression can increase to a maximum of 30 fold, allowing heat production. A hypothesis for this occurring is that the conversion of GMP to IMP potentially increase adenylosuccinate (precursor of AMP), which allows for the production of a second messenger cAMP. This messenger is important for the BAT heat production.
Clinical significance
It has been realized that GMPR and its products increases in Alzheimer's disease. The GMPR gene encodes for the protein GMPR1 (GMP reductase enzyme) that catalyzes the reaction for converting GMP to IMP. IMP can also be converted to AMP and adenosine (A). The presence of the adenosine can bind to A1/A2 receptors (important for mediation of Tau phosphorylation) which ultimately results in increased expression of Alzheimer's disease. This is because Alzheimer's disease is due to neurofilament tangles (NFT) forming inside neurons, and phosphorylation of tau is one of the reasons for why the tangles form. Activation of the adenosine receptors increases the tangling of neurofilaments so Alzheimer's disease patients' conditions will worsen. By testing for possible inhibitors of GMPR1, it can help eliminate Tau phosphorylation.
GMPR is also involved in the skin cancer melanoma. For patients with melanoma, expression of GMPR becomes reduced. An important role that GMPR plays in melanoma is that it reduces Rho-GTPases and it prevents melanoma cells from forming invadopodia, breaking down the extracellular matrix, and growing as tumors. It does this by using up or essentially decreasing the amount of GTP available. This decreases the supply of guanosine available and therefore, decrease the potential of having an invasive property. By decreasing the amounts of GMPR, it increases the chance of invasion and symptoms of melanoma to occur. Therefore, GMPR is needed to suppress melanoma invasion.
GMPR also plays a role in leukemia. It has been found that in the cases of promyelocytic leukemia cells being differentiate to monocytes, the expression of GMPR has increased by a lot. Therefore, the gene for GMPR can also be a potential target for the treating leukemia.
See also
Purine metabolism
References
External links
Proposed catalytic mechanism: Mechanism and Catalytic Site Atlas - GMP Reductase
EC 1.7.1
Oxidoreductases | GMP reductase | Chemistry | 1,368 |
22,819,912 | https://en.wikipedia.org/wiki/Acaulospora%20thomii | Acaulospora thomii is a species of fungus in the family Acaulosporaceae. It forms arbuscular mycorrhiza and vesicles in roots. Found in Poland growing under Triticum aestivum, it was described as a new species in 1988.
References
Diversisporales
Fungi described in 1988
Fungi of Europe
Fungus species | Acaulospora thomii | Biology | 76 |
21,566,434 | https://en.wikipedia.org/wiki/QPACE | QPACE (QCD Parallel Computing on the Cell Broadband Engine) is a massively parallel and scalable supercomputer designed for applications in lattice quantum chromodynamics.
Overview
The QPACE supercomputer is a research project carried out by several academic institutions in collaboration with the IBM Research and Development Laboratory in Böblingen, Germany, and other industrial partners including Eurotech, Knürr, and Xilinx. The academic design team of about 20 junior and senior scientists, mostly physicists, came from the University of Regensburg (project lead), the University of Wuppertal, DESY Zeuthen, Jülich Research Centre, and the University of Ferrara. The main goal was the design of an application-optimized scalable architecture that beats industrial products in terms of compute performance, price-performance ratio, and energy efficiency. The project officially started in 2008. Two installations were deployed in the summer of 2009. The final design was completed in early 2010. Since then QPACE is used for calculations of lattice QCD. The system architecture is also suitable for other applications that mainly rely on nearest-neighbor communication, e.g., lattice Boltzmann methods.
In November 2009 QPACE was the leading architecture on the Green500 list of the most energy-efficient supercomputers in the world. The title was defended in June 2010, when the architecture achieved an energy signature of 773 MFLOPS per Watt in the Linpack benchmark. In the Top500 list of most powerful supercomputers, QPACE ranked #110-#112 in November 2009, and #131-#133 in June 2010.
QPACE was funded by the German Research Foundation (DFG) in the framework of SFB/TRR-55 and by IBM. Additional contributions were made by Eurotech, Knürr, and Xilinx.
Architecture
In 2008 IBM released the PowerXCell 8i multi-core processor, an enhanced version of the IBM Cell Broadband Engine used, e.g., in the PlayStation 3. The processor received much attention in the scientific community due to its outstanding floating-point performance. It is one of the building blocks of the IBM Roadrunner cluster, which was the first supercomputer architecture to break the PFLOPS barrier. Cluster architectures based on the PowerXCell 8i typically rely on IBM BladeCenter blade servers interconnected by industry-standard networks such as Infiniband. For QPACE an entirely different approach was chosen. A custom-designed network co-processor implemented on Xilinx Virtex-5 FPGAs is used to connect the compute nodes. FPGAs are re-programmable semiconductor devices that allow for a customized specification of the functional behavior. The QPACE network processor is tightly coupled to the PowerXCell 8i via a Rambus-proprietary I/O interface.
The smallest building block of QPACE is the node card, which hosts the PowerXCell 8i and the FPGA. Node cards are mounted on backplanes, each of which can host up to 32 node cards. One QPACE rack houses up to eight backplanes, with four backplanes each mounted to the front and back side. The maximum number of node cards per rack is 256. QPACE relies on a water-cooling solution to achieve this packaging density.
Sixteen node cards are monitored and controlled by a separate administration card, called the root card. One more administration card per rack, called the superroot card, is used to monitor and control the power supplies. The root cards and superroot cards are also used for synchronization of the compute nodes.
Node card
The heart of QPACE is the IBM PowerXCell 8i multi-core processor. Each node card hosts one PowerXCell 8i, 4 GB of DDR2 SDRAM with ECC, one Xilinx Virtex-5 FPGA and seven network transceivers. A single 1 Gigabit Ethernet transceiver connects the node card to the I/O network. Six 10 Gigabit transceivers are used for passing messages between neighboring nodes in a three-dimensional toroidal mesh.
The QPACE network co-processor is implemented on a Xilinx Virtex-5 FPGA, which is directly connected to the I/O interface of the PowerXCell 8i. The functional behavior of the FPGA is defined by a hardware description language and can be changed at any time at the cost of rebooting the node card. Most entities of the QPACE network co-coprocessor are coded in VHDL.
Networks
The QPACE network co-processor connects the PowerXCell 8i to three communications networks:
The torus network is a high-speed communication path that allows for nearest-neighbor communication in a three-dimensional toroidal mesh. The torus network relies on the physical layer of 10 Gigabit Ethernet, while a custom-designed communications protocol optimized for small message sizes is used for message passing. A unique feature of the torus network design is the support for zero-copy communication between the private memory areas, called the Local Stores, of the Synergistic Processing Elements (SPEs) by direct memory access. The latency for communication between two SPEs on neighboring nodes is 3 μs. The peak bandwidth per link and direction is about 1 GB/s.
Switched 1 Gigabit Ethernet is used for file I/O and maintenance.
The global signals network is a simple 2-wire system arranged as a tree network. This network is used for evaluation of global conditions and synchronization of the nodes.
Cooling
The compute nodes of the QPACE supercomputer are cooled by water. Roughly 115 Watt have to be dissipated from each node card. The cooling solution is based on a two-component design. Each node card is mounted to a thermal box, which acts as a large heat sink for heat-critical components. The thermal box interfaces to a coldplate, which is connected to the water-cooling circuit. The performance of the coldplate allows for the removal of the heat from up to 32 nodes. The node cards are mounted on both sides of the coldplate, i.e., 16 nodes each are mounted on the top and bottom of the coldplate. The efficiency of the cooling solution allows for the cooling of the compute nodes with warm water. The QPACE cooling solution also influenced other supercomputer designs such as SuperMUC.
Installations
Two identical installations of QPACE with four racks have been operating since 2009:
Jülich Research Centre
University of Wuppertal
The aggregate peak performance is about 200 TFLOPS in double precision, and 400 TFLOPS in single precision. The installations are operated by the University of Regensburg, Jülich Research Centre, and the University of Wuppertal.
See also
QPACE2, a follow-up project to QPACE
Supercomputer
Cell (microprocessor)
Torus interconnect
FPGA
Lattice QCD
References
Supercomputers
Cell_BE_architecture
Parallel computing | QPACE | Technology | 1,463 |
14,081,814 | https://en.wikipedia.org/wiki/MENTOR%20routing%20algorithm | The MENTOR routing algorithm is an algorithm for use in routing of mesh networks, specifically pertaining to their initial topology. It was developed in 1991 by Aaron Kershenbaum, Parviz Kermani, and George A. Grove and was published by the IEEE.
Complexity
Empirical observation has shown the complexity class of this algorithm to be O(N²), or quadratic. This represents "a significant improvement over currently used algorithms, [while still yielding] solutions of a quality competitive with other, much slower procedures."
Methodology
The algorithm assumes three things are conducive to low-"cost" (that is, minimal in distance travelled and time between destinations) topology: that paths will tend to be direct, not circuitous; that links will have a "high utilization"—that is, they will be used to nearly their maximum operating capacity; and that "long, high-capacity links [will be used] whenever possible."
The overall plan is to send traffic over a direct route between the source and destination whenever the magnitude of the requirement is sufficiently large and to send it via a path within a tree in all other cases. In the former case, we are satisfying all three of our goals--we are using a direct path of high utilization and high capacity. In the latter case we are satisfying at least the last two objectives as we are aggregating traffic as much as possible.
The minimum spanning tree on which traffic flows in the latter case is heuristically defined by Dijkstra's algorithm and Prim's algorithm.
References
Aaron Kershenbaum, Parviz Kermani, George A. Grover. "MENTOR: An Algorithm for Mesh Network Topological Optimization and Routing", IEEE Transactions on Communications, April 1991. Accessed November 4, 2007.
Routing algorithms
Mesh networking | MENTOR routing algorithm | Technology | 367 |
17,644,328 | https://en.wikipedia.org/wiki/List%20of%20parasites%20of%20humans |
Endoparasites
Protozoan organisms
Helminths (worms)
Helminth organisms (also called helminths or intestinal worms) include:
Tapeworms
Flukes
Roundworms
Other organisms
Ectoparasites
References
Parasites
parasites of humans | List of parasites of humans | Biology | 53 |
68,704,780 | https://en.wikipedia.org/wiki/Barium%20bromate | Barium bromate is a chemical compound composed of the barium ion and the bromate ion, with the chemical formula of Ba(BrO3)2.
Preparation
Barium bromate can be prepared by reacting potassium bromate with barium chloride:
References
Barium compounds
Bromates | Barium bromate | Chemistry | 58 |
28,955,715 | https://en.wikipedia.org/wiki/DP%20cell | A DP cell is a device that measures the differential pressure between two inputs.
Example:
To measure the pressure difference between a container (or vessel) and the surrounding atmosphere, you may connect 'Hi' port of the DP-cell to a fitting that enters the vessel, using suitable tubing. The 'Lo' port, you leave open to the atmosphere (open air, or possibly through a buffer or desiccant chamber). The DP-cell will indicate the relative difference between the pressure of the vessel (container) and the atmospheric pressure.
This signal is often wired to an indicator that reads out locally, or remotely in a control room, and/or as a control (or feedback) signal to a valve, pump, or other control element to maintain a set pressure, or limit a maximum pressure.
Typically, the signal is 4-20 mA DC loop current, where, usually, 4mA represents the minimum differential pressure and 20mA represents the maximum differential pressure.
. Alternatively, the signal may be a variable voltage, or digital information stream.
References
Pressure gauges
Measuring instruments | DP cell | Technology,Engineering | 224 |
61,545,303 | https://en.wikipedia.org/wiki/Crown%20vs%20Kate%20Dover | The trial of Kate Dover of February 1882, before Mr Justice Cave, was a major event at the criminal court in Leeds Town Hall, Leeds, West Yorkshire, England. It was attended by many people, and attracted much newspaper publicity. It followed the death of Kate Dover's 61-year-old employer and lover, Thomas Skinner from arsenic poisoning. Known as the Queen of Heeley for her fashionable taste in clothes, Dover was 27 years old at the time, and was Skinner's housekeeper. She was convicted of manslaughter, and sentenced to penal servitude for life, which she served at Woking Female Prison. By 1901, she was out of jail. She lived her remaining years with her sisters in Rotherham.
Kate Dover, perpetrator
Kate Dover (Sheffield, 1855 – Rotherham, 26 March 1925) was the daughter of a woodcarver. She lived with her family at 4 Thirlwell Terrace, Heeley, Sheffield, in the West Riding of Yorkshire. According to The Scotsman and The Sheffield Independent, Dover was known as the Queen of Heeley due to her use of make-up and fashionable clothes. She became a housekeeper to Thomas Skinner of 24 Glover Place, Sheffield, who was also her "sweetheart".
Thomas Skinner, victim
Thomas Skinner (Sheffield, 16 June 1819 – Sheffield, 6 December 1881) was an etcher, inventor and amateur oil-painter. When he met the 26-year-old Kate Dover in 1880, he was a widower aged 60 years, a drunkard, and was fairly well-to-do as a result of the income from his invention which related to etching on steel blades.
Events
Background
A previous employee of the victim played a major part in the events surrounding the crime. She was Mrs Jane Jones, who before her marriage was briefly a shop assistant at Cole Brothers, Fargate, then entered service as Skinner's wife Mellond's nurse in 1874, becoming his housekeeper in 1876 when Mellond died. Jane married William Jones in February 1878 and he moved into Glover Place with her and Skinner. That situation continued until 1880. Skinner had taught Jane his trade, and she "assisted him considerably" in his work. "So proficient had this woman become that there was a kind of partnership between Mr and Mrs Jones and (Skinner) with regard to the household expenses; they shared the profits." In total, by spring 1880 Jane Jones had been Skinner's housekeeper "for nearly three years."
In 1880, Dover "kept a confectioner's shop", also described as a spice shop, in London Road, Sheffield, and Skinner was still living at 24 Glover Place. Dover and Skinner met at the sweet shop in April 1880, she asked to see his paintings, and they began to visit each other. In response, Jane Jones and her husband left Skinner's house in September of the same year because they "objected to the conduct" of Dover. "From what was observed by Mr. Jones, and Mrs. Jones also, Mr. Jones did not think it advisable his wife should stay longer in the deceased's house." Later, Ada Wheatley gave an example of this behaviour, which she observed on the day when the onions were delivered: "Kate Dover was sitting on Mr Skinner's knee, and he said to (Dover), Lay down, love, and let us have a nap." Roasan Biggins, a niece of Skinner, took over as housekeeper for six weeks, then Dover took over her position. By that point, Skinner was already courting Dover "with a view to marrying her." The neighbour Elizabeth Guest at number 25 said that Skinner gave Dover ten shillings per week as household expenses, but expected a daily quart of beer and quart of milk out of this money, so that the limited funds forced Dover to pawn Skinner's belongings, such as "his tea service and suit of black clothes." Unlike Jones, Dover did not live with Skinner, but returned "home to Heeley at night." The 1881 Census shows Skinner living alone.
Although the relationship between Skinner and Dover was initially "amicable", by June 1881 it had deteriorated into "quarrels", "bickerings" and "many complaints" from Skinner that Dover had "been in the habit of taking his property out of the house and pawning it. The best tea service, he said, had gone, his best suit of clothes had been pawned, and the quarrels continued up to that time with aggravation." Once, Skinner "resorted with actual violence" towards Dover. This state of affairs continued through November and early December 1881. The last two major quarrels were witnessed by the neighbour Elizabeth Guest, who said that Skinner was angry about the pawning of his property, and used "very bad language" to Dover, "who, after being reviled, threw her arms round his neck and pleaded for forgiveness." Nevertheless, Dover said later that they had spoken of marriage. Elizabeth Guest said that Dover had spoken of marriage with Skinner, and Kate Dover's mother Catharine Dover later confirmed that the couple were engaged. Skinner would say sometimes that he had made a will in favour of Jane Jones, but suggested that he would change it in favour of Kate Dover. In early November, Dover was looking for a house of her own, and complaining about Skinner's behaviour regarding money. On 18 November 1881 Dover accidentally dropped a cheque which had been tampered with. The cheque was picked up by a bystander and later handed to the police.
Purchase of poison
On 2 December 1881, Jane Jones received a gift of produce including onions and potatoes, "from her husband's brother in Bedfordshire". On the same day she and her husband ate some of the produce, and forwarded the remainder, including "fifteen potatoes, four large onions and some apples" to Thomas Skinner. Ada Wheatley delivered the vegetables. On receipt, Skinner said, "These are extra to what we get here", but Dover said "Humph", and "pitched the onions down the cellar steps". On the same day, Dover asked the chemist J.J. Redding for prussic acid on sugar to kill a cat, but he refused because cats do not eat sugar.
On 5 December, Skinner was in good health, working, "eating heartily" and "calling for his beer". At the same time, Dover was declaring him "very ill indeed; and she intimated a suspicion that he might die". At 7 pm Skinner visited the Mason's Arms at Norton Woodseats, known then and now as the Big Tree Inn, leaving Dover at his house. However at 7:30 pm Dover went to Mr Hewitt the chemist on Abbeydale Road, Sheffield, asking for an ounce of arsenic. She brought with her as a witness the butcher William Wood of London Road, Heeley, telling him two untruths: that their acquaintance Mr Marshall or Maxwell had previously acted at her witness (Marshall or Maxwell denied that subsequently), and that she was purchasing arsenic for colouring wax flowers (it was confirmed at the trial that arsenic on its own is not a colourant and that there were no wax flowers in the house). John William Arding the assistant sold her one-ounce avoirdupois of arsenic in powder form, in a "peculiar shaped packet, labelled poison in black letters upon a red ground, so that it could not easily be mistaken". As Dover left the chemist's shop, she declared, "Now I have got it I will take the lot". She then joined Skinner at the Big Tree Inn, where she and Skinner were "quite friendly" enough to be regarded as lovers, he offered to buy her a pony, and the couple left together at a quarter to nine. The inn was "a favourite resort of 'courters' ...the pair were "freely known as the 'Heeley Queen and her old sweetheart'".
A different story was told by Kate Dover's mother Catharine at the inquest. She said that her daughter had "bought the poison at Mr Skinner's request, and that he told her to say it was for artificial flowers or anything, that her daughter gave it to Mr Skinner that evening...that Mr Skinner put it in his waistcoat pocket, and...she had never clapped eyes on it again". Catharine's supposition was that Skinner had accidentally mixed the arsenic with his etching chemicals, and these chemicals had accidentally mixed with the food in the kitchen. This story did not make it to the Leeds Assizes in 1882. On 6 December, Dover told another witness, Mr Taylor, that "Mr Skinner was very ill and she feared he would die". However, when the servant Emma Bolsover brought back a fowl which Dover had sent her to collect at 10 am, she heard Skinner call out three times for his dinner, showing no sign of illness.
Poisoning
Thomas Skinner was killed on 6 December 1881. On that morning, Dover told Taylor that Skinner "was very ill, and always dozing and sleepy, and said she believed he would die", when in truth he "appeared to have been in his usual state of health". Dover "was the one that made the dinner and attended to it in all respects". Although Dover had prepared a roast chicken, she made goose stuffing with herbs, bread and onions, not chicken stuffing of forcemeat or sausage meat as was usual in the Victorian era. Moreover, she split the stuffing into two portions, cooking one portion inside the chicken, and one in a separate tin. Dinner consisting of stuffed chicken and Yorkshire pudding was served around midday, but the servant Emma Bolsover ate a lamb chop separately in the kitchen and did not join Dover and Skinner for the meal. Skinner called out for his meal, saying that "he did not know when he felt so hungry as he did then", however he had to wait another half-hour for his meal. Skinner's plate was piled with stuffing but Dover's was much less so. Five minutes after beginning the meal, Dover declared herself ill. Skinner immediately said, "I feel bad too...My God, she has done for us both this time," referring to Jane Jones who had sent the onions. He then "vomited, very considerably", and "seemed to be suffering very much". Dover "seemed to have got frightened, (possibly) at the results of administering the poison, and was trying to remedy what she had done".
Emma was sent to purchase tincture of lobelia, which can be used somewhat unsafely as an emetic at high doses. Dover could not wait until Bolsover's return, panicked, and followed her by tram. After they returned, Dover sent Bolsover to fetch Catharine Dover, who arrived surprised to find Skinner so ill. Meanwhile, Dover said she felt sick, and appeared to heave, but did not vomit at all until the doctor administered an emetic later. Dover "seemed to have been alarmed, and did what she could to render assistance". When the surgeon and forensic scientist James Wallin Harrison arrived at 2.30 pm, Skinner was "vomiting very seriously and heavily" and Dover said, "We have both been poisoned; it is that woman who has done us both." Harrison saw that Skinner was dying of arsenic poisoning, gave what care he could, and searched for the source of the poison. The vomit from Skinner which was in the scullery sink, vomit from Dover as a result of the emetic, besides the remains of the chicken, the stuffing, some excreta and some wine, were therefore respectively bottled for tests and analysis. Harrison left at 4:00 pm and returned in the evening, when "he found Skinner's skin cold and clammy, his countenance pinched, his hands and feet benumbed, and symptoms of collapse", while Dover showed no poisoning symptoms. Harrison stayed with Skinner until he died at 8:40 pm.
Dover said that just before Skinner died he requested that some papers be burned, although the doctor and inspector had witnessed that he did not. While the doctor and inspector were in the scullery with the dying Skinner, Dover was seen by Skinner's neighbour Elizabeth "Sissie" Guest fetching papers from upstairs, including a large blue or white paper, and burning them in the kitchen fire. She was also seen handing a paper containing powder to her mother, telling Catharine to hide it under her skirt in case Kate were searched by police. Before burning the papers, "(Dover's) conduct had been very excited, but it then changed completely. It was quite calm." Dover afterwards told Inspector Bradbury of the police that she had not burned any. She also denied that there had been arsenic in her possession or in the house, and thereafter she maintained that story. She even asked to be searched before leaving the house, but Bradbury refused. Inspectors Bradbury and Womack found no Will for Skinner, although Dover told Skinner that there was a Will, that she did not know its whereabouts, and that Skinner had planned to alter it. Womack found no arsenic in the house, and arsenic was not used in Skinner's etching process. Only Dover had prepared dinner that day. According to Jane Jones, she and her husband had eaten the same batch of vegetables with no ill effect, Jane bore no ill will towards Dover, and had not threatened to "do for them both". By tea time, both of Dover's parents were in the house. Everyone left the house together at 11 pm, Dover taking Skinner's cat and bird with her. After the death, household linen and American bonds went missing, although Skinner's cash book remained, and Inspector Womack had found fourteen sovereigns and a diamond ring in Skinner's bedroom on the day of his death. Other items found in the house were love letters between Dover and an unknown elderly man named "Emerson" hidden in a picture frame, and "applications for loans made by Mrs Dover to various persons".
Post mortem and inquest
At the post mortem by the surgeon Harrison on 8 December 1881, examination of the body brought a conclusion of "metallic irritant poisoning". Alfred H. Allen, Sheffield's public analyst, examined Skinner's entrails and the jars of samples held by the police on 10 December. The chicken and its inner stuffing were clear of arsenic, but the stuffing cooked separately in a tin was "loaded with arsenic", sufficiently to kill. He calculated that there were eight grains of arsenic "in the whole stomach", and a "considerable quantity of arsenic" in one sample of stuffing. He found little or no arsenic in the rest of the food and in one sample of vomit. Allen later said that "two grains of arsenic would be a fatal dose. There were 437.5 grains in an ounce". At the inquest of 18 December it was confirmed that Skinner's body was "without disease". The lining of the stomach was congested, and there were "large ulcerations, indicative of poisoning". Skinner's death was "consistent with poisoning by arsenic". Kate Dover was arrested on 18 December at Highfield Police Station, then held at the central police offices at Sheffield.
The inquest into the death of Skinner was opened at the Royal Hotel (later called the Victoria Inn) at the convergence of London Road and Abbeydale Road, Sheffield, on 9 December 1881, and reopened at 1.00 pm on 18 December 1881. Kate's mother Catharine gave evidence "full of contradictions to other witnesses" in place of her daughter who was ill. She spoke of the affection between Kate Dover and Skinner, Kate's need to use make-up to hide her pallid complexion, and the innocent purposes for which Kate obtained various poisons. The coroner published more than thirty love notes between Dover and an old man of 85 years. These had been found hidden in a picture frame at Skinner's house. The letters make clear that Skinner knew about and did not object to meetings between Dover and the old man "Emerson" or "E.M.", who regularly gave her money for clothes. The jury decided twelve to three that Dover had administered the poison to Skinner. The coroner recorded that Dover "wilfully and of malice aforethought did kill and murder the said Thomas Skinner".
Remand of Kate Dover
Between 6 and 16 December 1881, Dover was kept at home, in a state of "extreme exhaustion", in Thirlwell Terrace under police supervision, ill, unable to go out, denying the crime, nursed by Emma Bolsover and under the care of the surgeon Harrison. On Friday 23 December 1881, Dover was formally charged with wilful murder by the Stipendiary at Sheffield police court in Sheffield Old Town Hall and committed to Leeds Assizes. When charged, "she replied, in a faint, husky voice, I am not guilty." In that Stipendiary session was W.E. Clegg, of W.F. Clegg & Sons, for the prosecution; it was Clegg whom Dover had named as the drawer-up of Skinner's missing Will, although the Court did not raise that point. Dover "appeared extremely weak, and it was with some difficulty that she was brought from her cell". She was defended by A.M. Wilson, of Binney, Sons & Wilson. It was accepted that the motive for the crime was unknown, however a promissory note for £8 10s from Dover's father to Skinner was found among Skinner's effects. It was later found that it was Skinner who had insisted on paying a printer's bill for Charles Dover's book of poetry, so that Charles Dover had responded with the promissory note; and Kate Dover was not involved in the transaction. Following the committal she was removed to Wakefield prison, where she spent time writing letters and drawing flowers to send home. She was allowed to wear her own clothes instead of "prison garb", and was said to be "sanguine that her innocence would be established". Her prisoner number was 3288. On 30 January she was removed to Armley Gaol to await her trial.
Letters home from Kate Dover
Letters written home from Wakefield Prison by Dover were published on 31 December 1881. They showed a skilled use of language, and contained poems, quotations, exhortations for confidence in her innocence and hope for her imminent freedom. On 7 January 1882, the Sheffield Daily Telegraph published a letter of 31 December 1881 from Dover at Wakefield Prison to her family, showing optimism, encouragement for her family and again an unexpected linguistic facility. For example: "There is one thing I am certain, and that is if I am to be blessed with freedom God will let the tiny flowers that nestle in the grass kiss these Wakefield feet as though they had never been there." The letter mentions a good relationship with both parents and other relatives, and asks them to feed her pets: "my squirrel, my tortoise, my Jack, my pussies and my birds." This was preceded on 3 January by another published letter, referring to her membership of the Good Templar lodge of which she was a member. They had prayed for her at midnight on New Year's Eve, and she wrote that at the same moment "there seemed to be a ray of light, like the rising of the sun that got brighter and brighter, till the gas, which is always burning in my cell at night, was lost in that other light."
Trial
On 31 January, Dover was removed from Wakefield Prison to Leeds, ready for her trial at the Leeds Assizes. Her mother Catharine Dover was permitted to accompany her and give her food, and on the next morning Dover had an interview with her solicitor A. Muir Wilson. She "presented him with half a sheet of notepaper upon which she had with no unskilful hand drawn in pencil a bunch of exotic flowers."
The trial took place on Monday 6 and Tuesday 7 February 1882 at Leeds Assizes, in the Criminal Court room of Leeds Town Hall. On the Monday, Dover was indicted before Justice Lewis Cave for wilful murder, and pleaded not guilty. The judge was "burly in person and bluff in manner, and looked, as he was, the very incarnation of sound commonsense." The Liverpool Daily Post described the scene:
The case had created the greatest possible public interest, and the court was densely crowded, admission being obtained by ticket. Indeed, never since the trial of Charles Peace has the public excitement been so intense, hundreds of people being unable to obtain admission. Ladies mustered in unusually strong force. The prisoner, upon being placed in the dock, walked very slowly, and appeared to feel acutely her terrible position. She sobbed violently, and pleaded not guilty in a feeble voice.
Dover was "deeply agitated and sad", and "closely veiled". Mr Waddy QC and Mr Barker spoke on behalf of the prosecution, and Mr Lockwood and Mr Stuart Wortley for the defence. On the Monday, Barker declared to the jury that the evidence showed that Dover did indeed knowingly poison Skinner, but there was no evidence as to her motive. The Sheffield Daily Telegraph described the scene at Leeds as follows:
This morning the court is as crowded as ever, the ladies' gallery being again filled by females of all ages, the majority of them as unlovely as ever, and all armed with sandwich baskets and satchels, prepared to wait till his Lordship rises. Again there are several hundreds of disappointed ones, who try to beguile the policemen into opening the door that they may go in. The officers, however, are hard of heart. They set their faces as flint against the fair suitors, promising that as soon as anybody comes out somebody will be permitted to enter ... Down below in the court there is a crowd of barristers, twirling their thumbs, reading the newspapers, writing letters, and generally industrious in other ways, particularly in making sketches, which the prisoner in the dock could have excelled with a few quick touches of her pencil. They occupy most valuable seats, which would be gladly filled by the Press, who, perched away in the ladies' gallery like the bird who sits up aloft, strain their ears to hear what counsel asks and what witnesses answer ... Kate Dover ... still appears feeble and ill. She is attired in black with sealskin jacket and black hat ... but soon after the proceedings are resumed she raises her veil, and everybody is able to see her features, which certainly do not form a heavy, unintellectual countenance, but the very opposite."
Lockwood, counsel for the defence, began his speech at 11:10 am by saying that "if she has taken the life of her master ... for that she must surely die." Now, just before Lockwood began his speech, her solicitor spoke to Dover, she averted her face and covered it with a handkerchief. She turned to face the jury, and there was a "great hush in court". Thereafter she appeared "greatly agitated". The Sheffield Daily Telegraph continues: "As Mr Lockwood gravely impresses on the jury that his client is there with her life trembling in the balance, her emotion is intense. From the gallery we can hear her sobbing, we can see her frame quivering, and her whole body rocking to and fro till she seems as if she would roll from her chair ... Several times her hand falls from her face, and it is evidently only by a supreme effort she prevents herself from fainting."
Lockwood spoke of the lovers' quarrels, reconciliations, words of love and talk of marriage. He said that "his hypothesis was that the prisoner had no intention of taking the artist's life. If she perpetrated the act at all, it was a mischievous act perpetrated not for the purpose of killing him, but for the reason only to suggest to his mind that Mrs Jones was unfriendly to him, and the reason for the act might have been suggested when the apples and onions came from Mrs Jones." He said that Dover's behaviour and manner of poisoning showed no "skilful hand" or calculation. He said, moreover, that Dover's panic for the lobelia emetic and the doctor's assistance showed innocence of intent to kill. Lockwood's speech was "not only eloquent, but so pathetic that many of the spectators found themselves, in a half-surreptitious, shame-faced way, wiping the tears from their eyes. Again the Sheffield newspaper describes Dover's reaction: "The prisoner's agitation increases at every sentence Mr Lockwood utters. She sobs bitterly, sways herself to and fro, and seems utterly lost in agony. Does the line of defence overwhelm her? It certainly offers her no hope or comfort, and seems to deepen the despair which has sat upon her all this morning." When the arsenic is mentioned, "the prisoner is again terribly affected – leaning forward, holding her head in her hands, swaying her body to and fro, and sobbing violently." Lockwood had spoken for nearly two hours.
Justice Cave's summing up took one hour. He gave the jury the following choice:
If they adopted the theory of the prosecution that she put the arsenic into the stuffing, and that she did it with the intention to kill him, then undoubtedly she would be guilty of murder. If they adopted the suggestion of the counsel for the defence that she put arsenic into the stuffing and did it only to cause some unpleasant symptoms and not with the intention of taking his life, and that the loss of his life was beyond her intention, that would not be murder, but manslaughter, and it would be their duty to find the verdict of manslaughter. If they did not think either of these theories were proper ones, or if the arsenic got there accidentally ... they must acquit her."
The Sheffield Daily Telegraph said that, "his closing words ... evidently caused the prisoner great agony, as she was again sobbing violently, and rocking her body to and fro as in serious pain." "The prisoner, who lifted her veil as she went, with tottering steps, from the dock, was exceedingly pale, and there were many traces of tears on her ashen face.
After two hours of deliberation by the jury, Dover returned to the dock "with painful step and slow. Her veil is raised, and though she walks with downcast head, we see she is very pale, and looks the image of despair. Who shall tell the agony which has been crowded into nearly two hours of waiting for the verdict? Now, as she stands with drooping head and twitching hands in the centre of the dock, she appears as if she had prematurely aged during the brief period she has been down below ... the prisoner appears as if she would totter from her feet." "She clasped the rail in front, and with bowed head waited for the words that might rudely cut short her life, or give her liberty." To the surprise of the court which expected either a hanging or an acquittal, Dover was found guilty of manslaughter. Justice Cave said:
Kate Dover, the jury adopted a view which was presented to them by your learned counsel, and they found you guilty of manslaughter; but the circumstances of your offence are so grave and so atrocious that they are separated but by a very thin line from the offence of murder. In such circumstances I must pass upon you the heaviest sentence in my power, and that is that you be kept in penal servitude for the term of your natural life."
"Not a sound escapes the prisoner's lips. Her head falls on her shoulders ... Without once raising her head to meet the hundreds of hungry eyes which are watching her every pang, Kate Dover turns from the railings and with melancholy gait and pitiful face passes down the steps and into the cells ... The crowd of females rustled out of Court, which is slow and noisy work. They have seen their unfortunate fellow-creature drain her bitter cup to the dregs, and they hurry home now to boast, no doubt, that they were present at the memorable trial of Kate Dover for murdering her master." Catharine Dover was permitted to speak with her daughter after the verdict. She reported Dover "in good spirits" but said that she blamed those who testified against her, rather than the process of law. Kate would bear her sentence with fortitude, looking forward to seeing her friends and relatives "when she came out ... Conscious of her innocence, she felt entirely unmoved by her conviction ... While in Wakefield she had made all love her ... and such she felt confident would be her case when she was in the new prison to which she might be sent." Kate Dover was sentenced on Wednesday 8 February, entering the dock "with slow step" and staggering to the rail to support herself by it with both hands, seeming hardly conscious of the proceedings. She did not reply to the sentence. Cave called her offence "atrocious" and sentenced her to penal servitude for life. Dover promptly fell "all of a heap" and was carried away to the cells. One juror said afterwards that the jury returned a manslaughter verdict because the majority did not want to hang a woman.
Imprisonment
Dover did not go straight to Woking Female Prison where she spent most of her sentence. On 21 February 1882 she was still at Wakefield, and expecting to be sent to Pentonville. However, by 1891, at age 36, Dover was a convict at Woking Female Prison at Knaphill, Woking, Surrey, listing her former profession as domestic housekeeper. Woking was the "first purpose-built female prison", opened in 1869 and closed in 1895 when the inmates were transferred to Aylesbury female prison which had been converted for women in the same year. At Woking, women could work in prison kitchens or the laundry. Some were paid to do tailoring, sewing or knitting. Woking had a mosaics department where the women broke up marble for mosaic flooring for installation at St Paul's Cathedral, the South Kensington museums and elsewhere.
In 1895 a petition to the Home Secretary – permitted after 15 years' servitude – was raised by the 1882 trial's counsels for her defence and the prosecution, for Dover's release from prison. However the Home Secretary declined the request. By 1901 Dover was out of prison, so she had probably served between thirteen and nineteen years.
Aftermath
Mrs Jane Jones (1853– Ecclesall 1883), Skinner's former housekeeper, died at Ecclesall Workhouse infirmary on 20 May 1883, citing injuries caused when her estranged husband William kicked and struck her on 12 May – although he denied it. Jane had married William Jones in February 1878, and, before the association of Skinner and Dover, had been living with Jones at Skinner's house. At the inquest at Sheffield on 21 May 1883, it was decided that because Jane Jones had separated from her husband since Skinner's death, had subsequently led a "most abandoned life", and had then died suddenly from a "congestion of the lungs", there was no necessity for a post mortem, and a verdict of "death from natural causes" would be returned.
Notes
References
External links
True Crime Library: True Crime August 1995. This issue features Kate Dover
Images of interior of former Town Hall Sheffield. This includes images of the yet-unchanged court room where Kate Dover was charged with wilful murder on 23 December 1881 at the Stipendiary Court.
1881 crimes in the United Kingdom
Arsenic
Culture in South Yorkshire
History of Yorkshire
Poisoning by drugs, medicaments and biological substances
Trials in England
1881 in England
Arsenic poisoning incidents | Crown vs Kate Dover | Chemistry,Environmental_science | 6,622 |
43,987,145 | https://en.wikipedia.org/wiki/Psychoanalytic%20infant%20observation | Psychoanalytic infant observation is a distinct empirical case study method in psychoanalytic and psychotherapy training which was developed at the Tavistock Clinic in London by child psychoanalyst Esther Bick. In 1948 she collaborated with John Bowlby to develop the approach as part of psychotherapy training. It has since become an essential feature of pre-clinical training in child and adult psychotherapy, psychoanalysis and related fields throughout the Western world.
Psychoanalytic infant observation usually involves observing an infant and mother weekly over a two-year period beginning soon after birth until the child's second birthday. This naturalistic form of experiential enquiry provides a unique opportunity to sharpen and extend the observational skills of future therapists. Trainees learn first-hand how a relationship develops between babies and their family members and enables them to think about how babies grow physically, mentally and emotionally. The experience of observing family life is invaluable for professionals who later work with complex and disturbing presentations.
Rationale for the method
Infant Observation was the inspired initiative of Esther Bick. As a Child Psychoanalyst she pioneered this particular approach to studying babies in the midst of their family environment. In 1948, she began teaching at the Tavistock Clinic and in collaboration with John Bowlby she started the practice of observation as an integral part of psychotherapy training. This involved finding families about to welcome a newborn and gaining their consent to freely participate in the two-year project. It consisted in visiting a family to observe their infant from birth to two years. These weekly observations in the natural environment of the baby's home offered a vivid learning experience of child development. Observers came to appreciate the mutual influence of the developing relationship between mother and baby, father and siblings (if any). Importantly, the observer was also invited to consider the feelings aroused in themselves during the observation and how their presence in the home could be influencing events.
Esther Bick's 1964 paper ‘Notes on infant observation in psycho-analytic training’ set out the model of infant observation and her view of how much can be learned from it — how to observe, the nature of early infantile anxiety, especially the baby's apparent fear of ‘falling to bits’, the impact of maternal anxiety and postnatal depression, and the significance of good observational capacities for future child analysts. She emphasized the gathering of data over time, the need to wait for meaning to emerge, and the observer's responsibility to respect their role as learner and to behave with tact and reliability.
Bick's ideas took shape at the same time as Wilfred Bion’s work on ‘A theory of thinking’ and these two explorations of the emotional and cognitive dimensions of the early mother-child relationship are profoundly complementary. Both build on the work of Melanie Klein and her pioneering analysis of children.
Later Developments of the method
Over the last fifty years courses for professionals working with children and families have made increasing use of infant and child observation as a central aspect of training. It has proved invaluable in increasing professional skills and in sensitising workers to the range of anxieties, difficulties and creative possibilities in each family.
From 1960 to 1980 Martha Harris was head of the Child Psychotherapy service at the Tavistock Clinic. She was responsible for the expansion in the number of British and international trainees at the Tavistock and for developing the training into what became known as the "Tavistock Model". The model, in which infant observation continues to play a pre-eminent role, has been adopted with modifications across the UK and internationally: for example, GERPEN in France and at the Martha Harris Study Centres in Italy.
Beginning in the 1980s, and initially supported by visiting staff from the Tavistock Clinic, courses in infant observation were developed to support the training of a wide range of professionals across the UK and across the West. Over time other components and seminars were added to develop a comprehensive programme leading to a post-graduate qualification. The post-graduate programme known as Psychoanalytic Observational Studies which is run under the auspices of the Tavistock Clinic is currently delivered in the UK in Belfast, Birmingham, Bristol, Devon, Oxford and Liverpool and in Italy, in Florence, Genoa and Milan. In the UK equivalent post-graduate programmes exist at the Anna Freud Centre and the British Psychotherapy Foundation in London, the Northern School of Child and Adolescent Psychotherapy with the University of Leeds, at the University of Northumbria in Newcastle and at Human Development, Scotland with the University of Strathclyde in Glasgow. In the US the programmes are run at the Washington School of Psychiatry, Washington, D.C. since 2004 and at Columbia University.
The Process of Observation
Psychoanalytic infant observation generally involves a weekly observation over a two-year period of an infant soon after birth and until their second birthday. Trainees normally undertake the observation in the home setting for one hour per week at the same time in the week, to fit in with the family's schedule. Trainees are responsible for finding a baby to observe under the guidance of their tutor. New observers attend seminars to discuss the practicalities of setting up an observation and to learn about the process of finding a baby.
Every observation is written up in detail as soon after the observation as possible. This can often take about an hour to complete. Students discuss their observations in small group seminars which take place on a weekly, over two academic years. Each trainee has the opportunity to present their detailed observations to the group. The presentations are anonymised and no identifying features are used.
The unique experience of psychoanalytic observation allows the trainee to observe a mother and baby, living through and resolving routine and difficult situations in their own ways, without any intervention from the observer. With the help of the seminar, the observer learns to process the inclination for judgmental and blaming thoughts which arise when anxiety is stirred. Along with developing sensitivity and precision in observation, the course teaches how to think freshly and inductively from observation, including trying to understand how the developing infant is making sense of his world.
The Young Child and Brief Observations
Some courses and trainings, including those at the Tavistock Clinic, The Birmingham Trust for Psychoanalytic Psychotherapy and the Northern School of Child and Adolescent Psychotherapy also offer the chance to undertake an observation of a pre-school child (approximately two to four years old) in their family or in a nursery setting for an hour a week for one academic year. This gives an opportunity for an additional understanding of development through the experience of observation as the child starts to communicate verbally and non-verbally with other children and with adults outside the immediate family and takes a range of steps towards the world outside the family.
Several courses provide the opportunity to undertake a brief infant or young child observation as a less intensive but still valuable training experience. (See for example Infant Mental Health and Early Intervention with Under Threes and their Parents.
International Journal of Infant Observation and Its Applications
Infant Observation, the journal, is published by Taylor and Francis and the current Editor is Trudy Klauber. The international journal publishes the best of the varied and original writing emerging from this field. It comprises case studies on infant and young child observation, research papers, and articles focusing on wider applications of the psychoanalytic observational method, including its relevance to reflective professional practice in fields such as social work, education and nursing. Papers are peer-reviewed. There is a developing body of research knowledge that draws upon the infant observation approach
See also
Psychoanalytic Study of the Child
Selma Fraiberg
Margaret Lowenfeld
Joel Ryce-Menuhin
James Robertson
Sandplay Therapy
References
Bibliography
Bick, Esther. (1964) ‘Notes on infant observation in psycho-analytic training’. Reprinted in Collected Papers of Martha Harris and Esther Bick. Clunie Press, 1987.
Harris, Martha. (1976). ‘The contribution of observation of mother-infant interaction and development to the equipment of a psychoanalyst’ Reprinted in M. H. Williams (ed.) (2011), pp. 117–132.
Harris, Martha. (1977) ‘The Tavistock training and philosophy’. Reprinted in The Tavistock Model: Papers on Child Development and Psychoanalytic Training by Martha Harris and Esther Bick, ed. M. H. Williams (London: Harris Meltzer Trust/ Karnac, 2011), pp. 1–24.
Reid, Susan. (Ed.) (1997) Developments in Infant Observation: The Tavistock Model. Hove: Routledge
Rustin, Margaret. (2009). 'Esther Bick's legacy of infant observation at the Tavistock – some reflections 60 years on',Infant Observation: International Journal of Infant Observation and Its Applications, 12(1), p. 32.
Rustin, Michael. (2006). ‘Infant observation research: What have we learned so far?’ Infant Observation: International Journal of Infant Observation and Its Applications, 9 (1), pp. 35–52.
Sternberg, Janine. (2005). Infant Observation at the Heart of Training. London: Karnac.
Waddell, Margot. (2013). ‘Infant observation in Britain: a Tavistock approach’. Infant Observation: International Journal of Infant Observation and Its Applications, 16(1), pp. 4–22.
External links
Videos of NSCAP students talking about the experience of undertaking Psychoanalytic Infant Observation
Tavistock Clinic
International Journal of Infant Observation and Its Applications
Esther Bick
British Psychotherapy Foundation
Birmingham Trust for Psychoanalytic Psychotherapy
Northern School of Child and Adolescent Psychotherapy
Human Development Scotland
Anna Freud Centre
Association of Child Psychotherapists
Washington School of Psychiatry
Child development
Psychoanalysis by type
Human development
Empiricism
Evidence
Critical thinking
Epistemology
Observation
Sources of knowledge | Psychoanalytic infant observation | Biology | 1,990 |
31,840,384 | https://en.wikipedia.org/wiki/Oklahoma%20Tribal%20Statistical%20Area | Oklahoma Tribal Statistical Area is a statistical entity identified and delineated by federally recognized American Indian tribes in Oklahoma as part of the U.S. Census Bureau's 2010 Census and ongoing American Community Survey.
Many of these areas are also designated Tribal Jurisdictional Areas, areas within which tribes will provide government services and assert other forms of government authority.
They differ from standard reservations, such as the Osage Nation of Oklahoma (not listed below), in that allotment was broken up and as a consequence their residents are a mix of native and non-native people, with only tribal members subject to the tribal government.
At least five of these areas, those of the so-called five civilized tribes of Cherokee, Choctaw, Chickasaw, Creek and Seminole (the 'Five Tribes' of Oklahoma), which cover 43% of the area of the state (including Tulsa), are recognized as reservations by federal treaty, and thus not subject to state law or jurisdiction for tribal members.
List
5 Tribes (Reservations)
Cherokee Nation
Chickasaw Nation
Choctaw Nation
Creek Nation (Muscogee)
Seminole Nation
Other
Caddo-Wichita-Delaware OTSA
Cheyenne-Arapaho OTSA
Citizen Potawatomi Nation-Absentee Shawnee OTSA
Eastern Shawnee OTSA
Iowa OTSA
Kaw OTSA
Kickapoo OTSA
Kiowa-Comanche-Apache-Fort Sill Apache OTSA
Miami OTSA
Modoc OTSA
Otoe-Missouria OTSA
Ottawa OTSA
Pawnee OTSA
Peoria OTSA
Ponca OTSA
Quapaw OTSA
Sac and Fox OTSA
Seneca-Cayuga OTSA
Tonkawa OTSA
Wyandotte OTSA
Joint Use Areas
Creek–Seminole JUA OTSA
Kaw–Ponca JUA OTSA
Kiowa–Comanche–Apache–Fort Sill–Caddo–Wichita–Delaware JUA OTSA
Miami–Peoria JUA OTSA
See also
List of Native American Tribes in Oklahoma
List of historical Indian reservations in the United States
Indian colony
Indian reserve, Canada
Oklahoma Indian Welfare Act
Ranchería
Rancherie, Canada
Aboriginal title in the United States
Former Indian reservations in Oklahoma
Indian country jurisdiction
Off-reservation trust land
Tribal sovereignty in the United States
References
External links
Oklahoma Office of Indian Affairs Commission
Aboriginal title in the United States
02
02
Political divisions of the United States
United States statistical areas
Former American Indian reservations | Oklahoma Tribal Statistical Area | Mathematics | 482 |
64,172,078 | https://en.wikipedia.org/wiki/Ordered%20algebra | In mathematics, an ordered algebra is an algebra over the real numbers with unit e together with an associated order such that e is positive (i.e. e ≥ 0), the product of any two positive elements is again positive, and when A is considered as a vector space over then it is an Archimedean ordered vector space.
Properties
Let A be an ordered algebra with unit e and let C* denote the cone in A* (the algebraic dual of A) of all positive linear forms on A.
If f is a linear form on A such that f(e) = 1 and f generates an extreme ray of C* then f is a multiplicative homomorphism.
Results
Stone's Algebra Theorem: Let A be an ordered algebra with unit e such that e is an order unit in A, let A* denote the algebraic dual of A, and let K be the -compact set of all multiplicative positive linear forms satisfying f(e) = 1. Then under the evaluation map, A is isomorphic to a dense subalgebra of . If in addition every positive sequence of type l1 in A is order summable then A together with the Minkowski functional pe is isomorphic to the Banach algebra .
See also
Ordered vector space
Riesz space
References
Sources
Functional analysis | Ordered algebra | Mathematics | 267 |
51,746,867 | https://en.wikipedia.org/wiki/Alkali%20metal%20nitrate | Alkali metal nitrates are chemical compounds consisting of an alkali metal (lithium, sodium, potassium, rubidium and caesium) and the nitrate ion. Only two are of major commercial value, the sodium and potassium salts. They are white, water-soluble salts with melting points ranging from 255 °C () to 414 °C () on a relatively narrow span of 159 °C
The melting point of the alkali metal nitrates tends to increase from 255 °C to 414 °C (with an anomaly for rubidium being not properly aligned in the series) as the atomic mass and the ionic radius (naked cation) of the alkaline metal increases, going down in the column. Similarly, but not presented here in the table, the solubility of these salts in water also decreases with the atomic mass of the metal.
Applications
Sodium and potassium nitrates are commonly used as fertilizers. As they are also strong oxidizers, they enter pyrotechnic compositions and the manufacturing of explosives.
Eutectic mixtures of alkali metal nitrates are used as molten salts. For example, a 40:7:53 mixture of NaNO2: NaNO3:KNO3 melts at 142 °C and is stable to about 600 °C.
A minor use is for coloring the light emitted by fireworks:
lithium nitrate produces a red color,
sodium nitrate produces a yellow/orange color,
potassium nitrate and rubidium nitrate produce violet colors,
caesium nitrate produces an indigo color.
In a general way, the emitted color progressively turns from the red to the violet in the visible spectrum of light when going down in the column of the alkaline metals in the periodic table of Mendeleev. It corresponds to a decrease of the wavelength of the light emitted during the electrons de-excitation step in the atoms brought at high temperature. The photons emitted by caesium are more energetic than these of lithium.
See also
Alkali metal hydride
Alkali metal halide
Ammonium nitrate
Nitric acid
References
Nitrates | Alkali metal nitrate | Chemistry | 417 |
2,838,331 | https://en.wikipedia.org/wiki/Muda%20%28Japanese%20term%29 | is a Japanese word meaning "futility", "uselessness", or "wastefulness", and is a key concept in lean process thinking such as in the Toyota Production System (TPS), denoting one of three types of deviation from optimal allocation of resources. The other types are known by the Japanese terms mura ("unevenness") and muri ("overload"). Waste in this context refers to the wasting of time or resources rather than wasteful by-products and should not be confused with waste reduction.
From an end-customer's point of view, value-added work is any activity that produces goods or provides a service for which a customer is willing to pay; muda is any constraint or impediment that causes waste to occur.
There are two types of muda:
Muda type I: non value-adding, but necessary for end-customers. These are usually harder to eliminate because while classified as non-value adding, they may still be necessary.
Muda type II: non value-adding and unnecessary for end-customers. These contribute to waste, incur hidden costs and should be eliminated.
Toyota's (Ohno's) seven forms of waste
One of the key steps in lean process and TPS is to identify which activities add value and which do not, then to progressively work to improve or eliminate them.
Taiichi Ohno, "father" of the Toyota Production System, originally identified seven forms of muda or waste:
A mnemonic may be useful for remembering the categories of waste, such as TIM WOOD or TIM WOODS (with the S referring to Skills).
Transporting
Every time a product is touched or moved unnecessarily there is a risk that it could be damaged, lost, delayed, etc. as well as being a cost for no added value. Transporting does not add value to the product, i.e. is not a transformation for which the consumer is willing to pay.
Inventory
Whether in the form of raw materials, work-in-progress (WIP), or finished goods, represents a capital outlay that cannot yet produce an income. The longer a product sits in one of these states, the more it contributes to waste. The smooth, continuous flow of work through each process ensures excess amounts of inventory are minimized.
Motion
In contrast to transportation, which refers to damage and transaction costs associated with moving the product, motion refers to the damage and costs inflicted on what creates the product. This can include wear and tear for equipment, repetitive strain injuries for workers or unnecessary downtime.
Waiting
Whenever the product is not in transportation or being processed, it is waiting (typically in a queue). In traditional processes, a large part of an individual product's life is spent waiting to be worked on.
Overproduction
Making more of a product than is required results in several forms of waste, typically caused by production in large batches. The customer's needs often change over the time it takes to produce a larger batch. Over-production has been described as the worst kind of waste.
Over processing
Doing more to a product than is required by the end-customer results in it taking longer and costing more to produce. This also includes using components that are more precise, complex, expensive or higher quality than absolutely required.
Defects
Having to discard or rework a product due to earlier defective work or components results in additional cost and delays.
Unused skills
Organizations often under-utilize the skills their workers have, or permit workers to operate in silos so that knowledge is not shared. In other words, the workers are over-skilled. This was added to the original seven forms of waste, as resolving this waste is a key enabler to resolving the others.
Alternative forms of waste
The eight forms of waste were developed for Toyota specific processes.
Other companies and individuals have elucidated or identified other forms of waste. Some examples follow:
Canon's nine wastes
Work-in-process waste: e.g., stocking items not immediately needed
Defect waste: producing defective products
Equipment waste: idle or broken machinery; empty facilities; taking too long for setup
Investment or expense waste: overuse of resources for required output
Indirect labor waste: excess personnel due to unskillful use of indirect labor
Human resources or talent waste: employing people whose talents exceed job requirements, when the job can be mechanized or assigned to less skilled people
Operations or motion waste: Not working according to the best standards.
Planning or product design waste: Implementing processes or producing products with more functionality than necessary.
Start-up waste: The waste or inefficiency in the ramp-up or stabilization of the production of a new product.
Confusion
General uncertainty about the right thing to do, or absence of documented procedures and operating statements.
Self-doubt
Writer Jim Womack described "thinking you can't" as the worst form of waste, quoting Henry Ford's aphorism:
Implementation
Shigeo Shingo divides process related activity into Process and Operation. He distinguishes "Process", the course of material that is transformed into product, from "Operation" which are the actions performed on the material by workers and machines. This distinction is not generally recognized because most people would view the "Operations" performed on the raw materials of a product by workers and machines as the "Process" by which those raw materials are transformed into the final product. Shingo breaks down the process into four phenomena, Transportation, Inspection, Processing and Delay. He makes this distinction because value is only added during the processing steps in the process not by the transportation, inspection and delay steps. He states that whereas many see Process and Operations in parallel he sees them at right angles (orthogonal) (see Value Stream Mapping). This starkly throws most of the operations into the waste category.
Many of the TPS/Lean techniques work in a similar way. By planning to reduce manpower, or reduce change-over times, or reduce campaign lengths, or reduce lot sizes, the question of waste comes immediately into focus upon those elements that prevent the plan being implemented. Often it is in the operations' area rather than the process area that muda can be eliminated and remove the blockage to the plan. Tools of many types and methodologies can then be employed on these wastes to reduce or eliminate them.
The plan is therefore to build a fast, flexible process where the immediate impact is to reduce waste and therefore costs. By ratcheting the process towards this aim with focused muda reduction to achieve each step, the improvements are 'locked in' and become required for the process to function. Without this intent to build a fast, flexible process there is a significant danger that any improvements achieved will not be sustained because they are just desirable and can slip back towards old behaviours without the process stopping.
See also
Lean manufacturing
Lean software development
Agile software development
Total quality management
Theory of Constraints
References
External links
"The 7 Manufacturing Wastes"
"8 Wastes of Lean Manufacturing"
Japanese business terms
Lean manufacturing
Toyota Production System | Muda (Japanese term) | Engineering | 1,430 |
13,664,138 | https://en.wikipedia.org/wiki/Myclobutanil | Myclobutanil is a triazole chemical used as a fungicide. It is a steroid demethylation (CYP51) inhibitor, specifically inhibiting ergosterol biosynthesis. Ergosterol is a critical component of fungal cell membranes.
Stereoisomerism
Safety
The Safety Data Sheet indicates the following hazards:
Suspected of damaging fertility or the unborn child.
Toxic to aquatic life with long lasting effects.
The first hazard has caused this chemical to be placed on the 1986 California Proposition 65 toxics list.
When heated, myclobutanil decomposes to produce corrosive and/or toxic fumes, including carbon monoxide, carbon dioxide, hydrogen chloride, hydrogen cyanide, and nitrogen oxides.
Banned for cannabis cultivation
Myclobutanil is banned in Canada, Colorado, Washington, Oregon, and Oklahoma for the production of medical and recreational cannabis. In 2014, a Canadian news investigation by The Globe and Mail reported the discovery of myclobutanil in medical cannabis produced by at least one government licensed grower. In September 2019, NBC News commissioned CannaSafe to test THC cartridges for heavy metals, pesticides, and residual solvents like Vitamin E; pesticides, including myclobutanil, was found in products from unlicensed dealers. In Michigan, the current state action limit for myclobutanil is 200 ppb in cannabis products.
References
External links
International Programme on Chemical Safety
Fungicides
Triazoles
4-Chlorophenyl compounds | Myclobutanil | Biology | 321 |
2,737,682 | https://en.wikipedia.org/wiki/Dicle%20Dam | Dicle Dam is one of the 21 dams of the Southeastern Anatolia Project of Turkey. These facilities are located within the provincial territory of Diyarbakır, at a distance of 50 kilometres to Diyarbakır city centre. More specifically, the dam and the hydroelectric power plant are located in Eğil district, at a distance of 800 metres from the point of junction of the streams of Maden Stream and Dibni to form the Tigris, and 22 kilometres downstream of the Kralkızı Dam. Construction works were started in 1986 and the dam was completed in 1997. The dam has an installed hydroelectric capacity of 110 MW and is designed to ultimately irrigate 128,080 hectares. In 2001 a water transmission line and a water treatment plant were commissioned that provided about 85% of the drinking water for the city of Diyarbakir in 2010. In 2018 a gate of the dam broke the water lever decreased and a part of a village re-emerged in the Eğil district.
References
GAP Regional Development Administration - Impounding started at Kralkızı and Dicle Dams
www.un.org.tr/undp/Gap.htm - United Nations Southeast Anatolia Sustainable Human Development Program (GAP)
www.ecgd.gov.uk Data sheet
External links
www.gap.gov.tr - Official GAP web site
Dams in Diyarbakır Province
Hydroelectric power stations in Turkey
Southeastern Anatolia Project
Dams completed in 1997
Rock-filled dams
Dams on the Tigris River | Dicle Dam | Engineering | 314 |
13,379,696 | https://en.wikipedia.org/wiki/Tuaminoheptane | Tuaminoheptane (, ; brand names Heptin, Heptadrine, Tuamine; also known as tuamine and 2-aminoheptane) is a sympathomimetic agent and vasoconstrictor which was formerly used as a nasal decongestant. It is still used in France as a nasal decongestant but its use is not recommended by the health authorities due to the lack of evidence of its effectiveness. It has also been used as a stimulant.
Tuaminoheptane has been found to act as a reuptake inhibitor and releasing agent of norepinephrine, which may underlie its decongestant and stimulant effects. It is an alkylamine. The chemical structure of the drug differs from that of other norepinephrine releasing agents, such as the phenethylamines, which, in contrast to tuaminoheptane, have an aromatic ring in their structure. Tuaminoheptane is also a skin irritant and can cause contact dermatitis via inhibition of volume-regulated anion channels, which limits its usefulness as a decongestant.
Tuaminoheptane is on the 2011 list of prohibited substances published by the World Anti-Doping Agency.
See also
1,3-Dimethylbutylamine
Heptaminol
Iproheptine
Isometheptene
Methylhexanamine
Octodrine
Oenethyl
References
External links
The World Anti-Doping Code. The 2011 Prohibited List. International Standard
Abandoned drugs
Alkylamines
Decongestants
Ion channel blockers
Norepinephrine releasing agents
Stimulants | Tuaminoheptane | Chemistry | 355 |
13,982,958 | https://en.wikipedia.org/wiki/Mork%20Goes%20Erk | "Mork Goes Erk" is the seventeenth episode of the first season of the American television sitcom Mork & Mindy. The episode aired on ABC on February 8, 1979. It was issued on VHS on January 1, 1998, as part of a two-episode special release that also included "Mork's First Christmas". It was issued on DVD on September 7, 2004, as part of the Mork & Mindy - The Complete First Season boxed set.
The episode was written by Lloyd Turner and Gordon Mitchell and directed by Howard Storm. In the episode, David Letterman portrays a self-help group leader named Ellsworth who offers "erk" (Ellsworth Revitalization Konditioning). The episode has been called a parody of the Erhard Seminars Training, or "est" course. The episode received mostly positive reviews, and was highlighted as one of the season's best episodes. David Letterman's performance also received good reviews.
Plot
Mork, Mindy and Mr. Bickley are all feeling depressed. Mindy has just learned that Mork's supervisor, Orson, has arranged for Mork to be transferred to another planet, and Bickley is suffering from writer's block. Their friend, Susan, visits and suggests that they all attend a seminar on Ellsworth's Revitalization Konditioning. As they arrive at the seminar, Ellsworth nervously asks Susan if all of the attendees' checks are in order. He lays out the rules for the duration of the training, which include no leaving and no alcohol consumption. When Bickley hears this, he promptly gets up to leave.
The seminar's attendees are given Ellsworth's harsh version of reality. Ellsworth preaches self-adoration, which he says will get rid of emotional highs and lows. He centers this goal around the notion of "finding our own space", while utilizing an authoritarian style of control as a therapeutic method to solve problems. The other attendees are shown to be passive consumers who seek any way to fix their personal issues. However, Mork begins to question the foundation of the course's rules, as well as the nature of the philosophical material that Ellsworth has put forth, by pointing out hypocrisy among Ellsworth's contradictory statements. In the end, Mork triumphs over Ellsworth's philosophy with universal humanistic moral values. Ellsworth dismisses Mork's victory, exclaiming, "I've got my Rolls-Royce!". However, Ellworth has had his Rolls-Royce stolen.
Cultural references
In a 1982 article in the journal, Theory & Society, Lewis & Clark College sociology professor, Robert Goldman, compared and contrasted Letterman's "Ellsworth" character and his training program to that of Werner Erhard's course, Erhard Seminars Training. Goldman noted that the episode spends time "lampooning Werner Erhard and est-like commercial pop psychologies". However, Goldman went on to note that the inherent problem with "Ellsworth Revitalization Konditioning" is not the training, but Ellsworth.
Ellsworth is seen as a parody of consumerism. "As the self-help entrepreneur, Ellsworth is portrayed as a walking collection of lifestyle-status points and sign-values... Conspicuous consumption and commodity fetishism define his personality." Goldman explained that this Mork and Mindy episode succeeds in distinguishing between criticism of Ellsworth's training, and criticism of Ellsworth, citing Ellsworth's character traits of "tyranny, selfishness, open greed, and flaunting of the accoutrements of his vulgar money-making".
Reception
TV Guide'''s 2005 book, TV Guide: The Ultimate Resource to Television Programs on DVD, highlights "Mork Goes Erk" as one of three "classic episodes" of the first season (including "Mork's First Christmas" and "Mork's Mixed Emotions").
Matthew Tobey of Allmovie wrote that the episode was most notable because of David Letterman's appearance before he became more well-known. The Dallas Morning News also praised Letterman's performance as a "shady motivational speaker", commenting that the episode was a way for Letterman to hone his "smarminess" before his later work on Late Show with David Letterman''. Jonathan Boudreaux of tvdvdreviews.com described Letterman as "a flakey EST-like guru", and called the episode "disjointed".
See also
est and The Forum in popular culture
Human Potential Movement
Large Group Awareness Training
New age
Parody
Parody religion
Pseudophilosophy
Self-help
References
External links
Mork and Mindy Online
Human Potential Movement
New Age in popular culture
Personal development
Parodies
1979 American television episodes
Werner Erhard | Mork Goes Erk | Biology | 1,016 |
6,721,300 | https://en.wikipedia.org/wiki/List%20of%20alpha%20emitting%20materials | The following are among the principal radioactive materials known to emit alpha particles.
209Bi, 211Bi, 212Bi, 213Bi
210Po, 211Po, 212Po, 214Po, 215Po, 216Po, 218Po
215At, 217At, 218At
218Rn, 219Rn, 220Rn, 222Rn, 226Rn
221Fr
223Ra, 224Ra, 226Ra
225Ac, 227Ac
227Th, 228Th, 229Th, 230Th, 232Th
231Pa
233U, 234U, 235U, 236U, 238U
237Np
238Pu, 239Pu, 240Pu, 244Pu
241Am
244Cm, 245Cm, 248Cm
249Cf, 252Cf
Alpha emitting
Alpha emitting | List of alpha emitting materials | Physics,Chemistry | 151 |
5,048,086 | https://en.wikipedia.org/wiki/Unisex%20public%20toilet | Unisex public toilets (also referred to as gender-inclusive, gender-neutral, mixed-sex or all-gender, or without any prefix at all) are public toilets that are not separated by sex or gender.
Unisex public toilets take different forms: they may be single occupancy facilities where only one single room or enclosure is provided; or multi-user facilities which are open to all and where users may either share sinks in an open area or each have their own sink in their private cubicle, stall or room. Unisex public toilets may either replace single-sex toilets, or may be an addition to single-sex toilets.
Unisex public toilets can be used by people of any sex or gender identity. Such toilet facilities can benefit transgender populations and people outside of the gender binary, and can reduce bathroom queues through more balanced occupation. Sex separation in public toilets (also called sex segregation), as opposed to unisex toilets, is the separation of public toilets into male and female; this separation is sometimes enforced by local laws and building codes. Key differences between male and female public toilets in most Western countries include the presence of urinals for men and boys, and sanitary bins for the disposal of menstrual hygiene products for women. (Sanitary bins may easily be included in the setup of unisex public toilets.)
The historical purposes of sex-separated toilets in the United States and Europe, as well as the timing of their appearance, are disputed amongst scholars. Safety from sexual harassment, and privacy, were likely two main goals of sex-separation of public toilets, and factors such as morality also played roles. Paternalism and resistance to women entering the workplace may have also played a role. Some women's groups hold that unisex public toilets will be less safe for women than public toilets that are separated by sex; however, some experts say that with the appropriate design interventions, these spaces can improve the safety of all users and reduce the disproportionately long wait times females face in sex-separated public washrooms.
The push for gender-neutral bathrooms is driven at least in part by the transgender community to protect against harassment and violence against this population. Unisex public toilets may benefit a range of people with or without special needs (e.g. people with disabilities, the elderly, and anyone who needs the help of someone of another gender or sex), as well as parents who need to help their infant or young child with using the toilet.
Terminology
Several alternative terms are in use for unisex public toilets. Some favor all-gender toilets, gender neutral toilets, gender free toilets or all-user toilets or just toilet. The "Public Toilet Advocacy Toolkit" by the NGO Public Hygiene Lets Us Stay Human (PHLUSH) in Portland, Oregon (United States) from 2015 uses the term "all-gender". More recently, they have changed to the term "all user". However, some object to the term "gender-neutral" and similar terms, believing that neither the spaces nor the terms are truly neutral. They also object to the replacement of the word "sex" with the word "gender". Such people often express a preference for the term "mixed-sex". But whatever one calls them, these are toilets which can (in theory) be used by anybody, regardless of sex or gender identity or presentation.
The opposite of unisex toilets is referred to as either "sex-separated" or "sex-segregated" toilets, or "conventional public toilets" (since sex separation is currently mostly the norm on the global level). In the United States some scholars have used the term "sex separation".
Designs
Types
Some unisex public toilets, whether of single or of multiple capacity, are designed to be used by people with disabilities. They can accommodate not only the physically disabled, but also elderly people who may require assistance from a carer of another gender, and other cases where public sex-segregated facilities might lead to discomfort. Toilet facilities for disabled people, especially those reliant on a wheelchair, may be either unisex or gender-specific.
Unisex public toilets are also common in cases where space is limited, such as in aircraft lavatories and passenger train toilets, or anywhere where a single toilet is made available.
Several types can be distinguished:
Single-occupancy toilets, which provide only one room or enclosure. This room can also in certain circumstances be used by several people at once, e.g. a whole family, a person with their caretaker.
Multi-user toilets, which are open to all and whose users may either share sinks in an open area or each have their own in their private cubicle, stall or room.
Relabeled sex-segregated multi-cubicle public toilets, with no other change. This approach was taken in one area at the Barbican Centre in the UK, where some toilets became designated as shared by both sexes.
Toilets
If more than one toilet fixture is available in a unisex public toilet, the toilet seats or squatting pans are installed in enclosed cubicles in the same way as in sex-segregated toilets. To ensure visual privacy, these may be provided with floor-to-ceiling walls.
Sinks
Sinks are commonly installed in open arrangement as in sex-segregated toilets and used collectively by people of all genders. One of the key design components supporting safety in multi-user facilities is the openness and visibility of the sink area from adjacent public corridors. This design intervention allows for passive surveillance of the space by relocating the shared sink area from the private to the public realm. Alternatively, a sink can be provided in each cubicle or toilet room, e.g. where the unisex toilet is set up to be used by families and carers. The latter arrangement is more friendly to people needing to use the sink in a manner calling for a degree of privacy, or taking off items of dress typically worn in public. Examples are emergency removal of menstrual blood stains from clothing; refreshing the upper body, face, or underarms over the sink; applying makeup; or combing and styling hair.
Urinals
The issue of urinals is creating somewhat of a conundrum for many unisex public toilet designers. In many public toilets, the widespread use of urinals for males means that there are more opportunities to meet their natural needs. There are often queues in front of the toilet rooms for females but not in front of the toilet rooms for males. While toilets are usually located in cubicles with lockable doors, urinals are usually installed freely in rows in sex-separated toilet rooms, separated only by side partitions if present at all. This design uses less space and water and is more sanitary than standing to urinate in a stall without a sink, especially where others defecate.
Urinals have primarily been offered in public toilets for males, with female urinals being only a niche product. Abolishing all urinals would sacrifice resource advantages and convenience for male users without improving sanitation or wait time for females. Another possibility would be to offer separate male and female urinals or unisex urinals that can be used by males and females alike, which allows increased flexibility of use. Yet this would raise the problem of arrangement. One option would be to continue to offer urinals in rows, with separation by screens. However, it is questionable whether the less private environment, compared to cubicle toilets, would be met with acceptance. Socio-cultural conventions make the concept of men or boys urinating with their backs visible to women or girls potentially uncomfortable for both genders, and this would currently seem aberrant and contrary to common morals and etiquette for many users.
There are other practical issues for females, such as women and girls needing toilet paper, having to lower their pants, and sometimes tending to their menstrual hygiene needs while using toilets. Alternatives would be to accommodate urinals for both sexes in cubicles, limiting their space advantages, or to continue to offer them only in public toilets assigned for males.
Urinals arranged in cubicles have seldom been installed; the advantages over conventional toilets were not obvious because the same space would still be required in the new arrangement. With all things considered, many unisex public toilet designers are now creating plans to place urinals in an isolated section or corner of the toilet room so that they will not be directly visible to anyone in other areas of the public toilet, balancing efficiency with modesty.
Building-related advantages
Where space is limited, sex-segregated sanitary facilities are not possible or must be limited. Unisex toilets are often used in many public transport systems, such as rail vehicles or airplanes, or by small businesses which provide a single toilet to their staff and customers.
Unisex public toilets cause fewer problems for caretakers of dependents who enter the toilet room together with their charge, such as a very young child, an elder, or a mentally or physically disabled person.
Women and girls often spend more time in toilet rooms than men or boys, for both physiological and cultural reasons. Urination takes longer inside a cubicle than at a urinal, and sanitation is a far greater issue often requiring more thorough hand washing. Females also make more visits to toilets. Urinary tract infections and incontinence are more common in females. Pregnancy, menstruation, breastfeeding, and diaper-changing increase usage. The elderly, who are disproportionately female because of the higher male death rate, make longer and more frequent toilet visits. Unisex public toilets can alleviate this problem by providing equal sanitation space for all genders, eliminating the prospect of unused cubicles in the male toilets.
Some argue that a two-tier system is also generated by a "toilet apartheid" that excludes women and girls from important social networking processes in male toilets. Important agreements and decisions by males are sometimes made at the urinal, where females are currently excluded.
Building-related disadvantages
The consolidation of previously gender-separated toilets or the construction of new unisex toilets is sometimes meets administrative and building-law resistance. The location of public toilets is sometimes dictated by existing plumbing design. If the only way to build unisex public toilets is to locate them in isolated spaces a long way from people in charge of supervising the space, such a design may be objectionable on safety grounds. Some argue that laws requiring that women and men be treated the same in public toilet access is unfair. Since the 1980s, "potty parity" activists have campaigned for laws requiring more female-designated public toilets than male-designated public toilets in public buildings, since women require more time to use the toilet and thus women's toilet rooms tend to have longer lines. California passed the first law of this kind in 1987, and as of 2009 twenty states in the US have passed similar legislation.
Locations
At private companies
Unless prohibited by law (and when required by law), private companies can provide unisex toilets.
At educational institutions
Transgender students may face violence or harassment from their peers when using gendered facilities. Advocates argue that forcing trans / non-binary students to use normative gendered public toilets can stigmatize them daily by singling them out. Those who oppose unisex facilities in schools frequently cite safety and privacy concerns for cisgender students.
United States
Many colleges and universities (such as Oberlin College in Ohio) have had unisex public toilets as early as 2000. Overwhelmingly, institutions that offer unisex spaces still also offer sex-separated spaces. The University of California at Los Angeles offers more than 160 unisex toilets on campus, but all are single stall. Other collegiate institutions have moved toward creating some unisex public toilets. According to a University of Massachusetts Amherst LGBTQ advocacy organization, The Stonewall Centre, there were more than 150 campuses in the US in 2014 with unisex public toilets.
In February 2016, South Dakota was the first state in the US to pass a bill that forces transgender students in public schools to use sanitation facilities that correspond with their 'chromosomes and anatomy' at birth.
The University of Oklahoma continually adds unisex toilets to their campus to accommodate students who may require use of a less excessively gendered public toilet. As of February 2014, the university had 13 unisex toilets.
There are over 150 college campuses across the US that are creating unisex public toilets. In March 2016, New York City private college Cooper Union moved to remove gender designations from campus toilets. In October 2016, University of California Berkeley converted several public toilets into unisex toilets.
In March 2017, Yelp announced that they will add a unisex public toilet finder feature on their app. Yelp was one of over 50 companies that signed an amicus curiae brief in favor of a transgender high school student Gavin Grimm who claims that his school board denied him access to the boys' toilet in school and thereby violating Title IX. HRC president Chad Griffin stated on the brief that "These companies are sending a powerful message to transgender children and their families that America's leading businesses have their backs."
United Kingdom
In 2015, unisex toilets were set to be introduced into every new school to be built in Scotland in a campaign to eradicate bullying. All future primary and secondary schools will have non-sex-separated toilets. In March 2017, the Glasgow City Council announced that toilets in school will no longer be labeled as 'girls' and 'boys' but instead be labelled as unisex to help students who may be struggling with the issue of gender identity. This will be implemented in three schools first.
In the United Kingdom, unisex public toilets are sometimes found on university campuses. In early 2013, Brighton and Hove city council introduced unisex toilets. British universities including Bradford Union, Sussex and Manchester, had already or were in the process of building unisex facilities in 2011.
Legislation and country examples
Brazil
The implementation of gender-neutral or unisex bathrooms, also called multigender toilets (), has sparked significant debate. Legislation varies across different states and municipalities. Some regions have introduced policies to promote the inclusion of gender-neutral bathrooms in public buildings and schools. For example, São Paulo has implemented measures to ensure that public schools provide gender-neutral bathroom options. These policies aim to protect the rights and dignity of transgender, travesti, and non-binary students, ensuring they have access to safe and inclusive facilities.
Canada
In April 2014, the Vancouver Park Board decided to install unisex toilets in public buildings, with different signs to identify them. Amongst the options discussed was the rainbow triangle (based on the pink triangle used during the Holocaust), an "all-inclusive" gender symbol, an icon representing a toilet or the phrases "washroom" or "gender-neutral washroom" placed on the entrances to the toilets. According to Global News, a Canadian online newspaper, many different regions across Canada offer unisex toilets and other gender-neutral facilities, but Vancouver was the first municipality to change building codes to require unisex toilets be built in public buildings. This movement, according to commissioner Trevor Loke, was aimed to make everyone feel welcomed and included: "We think that the recommendation of universal washrooms is a good idea [...] [w]e will be using more inclusive language based on the BC Human Rights Code." Some initiatives to make public toilets more diverse and inclusive have focused on language simply by using the phrases "toilet" or "gender-neutral toilet" in order to be inclusive of all genders and gender identities, or using specifically geared language such as "women and trans women" as opposed to just "women" (and vice versa for men and trans men).
China
Unisex toilets have appeared in China since before 2013 in Shenyang and Chengdu by 2015. In 2016, Shanghai opened its first public unisex toilet near the Zhangjiabin River in a park, in the Pudong district. Many of these toilets have opened in high-traffic areas for the convenience of all users, rather than specifically for the benefit of sexual minorities. In May 2016, a Beijing-based non-governmental organization launched an 'All Gender Toilets' campaign to bring awareness to this issue in China. This resulted in around 30 locations opening unisex public toilets.
India
In 2014, the Indian Supreme Court gave transgender people, also known as 'hijras', recognition with a third gender. This legislation included creating separate toilets for transgender people in public spaces where transgender people are often met with violence and hostility. The two-judge Supreme Court bench was led by Justice KS Radhakrishnan, who said, "The court order gives legal sanctity to the third gender. The judges said the government must make sure that they have access to medical care and other facilities like separate wards in hospitals and separate toilets". In 2017, The Union Ministry of Drinking Water and Sanitation sent out guidelines to the Swachh Bharat Mission decreeing that members who are part of the transgender community should be allowed to use the public toilet they are most comfortable with.
The central government has allowed transgender people to use the toilets of their choice in public and community toilets. This does not ensure safety from violence.
Japan
As of 2016, no laws were in place regarding the usage of public toilets in relation to gender identity. There may, however, be occasional signs outside public toilets to indicate that the stall is "gender free". The Tokyo city government was planning to install one unisex toilet in at least seven out of eleven of the buildings being used for the Olympic Games that were planned for 2020.
Nepal
MP Sunil Babu Pant used part of the Parliamentarian Development Fund to build the first two unisex toilets in Nepalganj, one of which is in Bageshwori Park. Starting in 2014, The Nepal Country Report, A Participatory Review and Analysis of the Legal and Social Environment for Lesbian, Gay, Bisexual and Transgender (LGBT) Persons and Civil Society recommended that in schools separate toilets or unisex toilets should be built for transgender students.
Thailand
The term "kathoeys" used to describe effeminate male-bodied people, for whom schools have started opening sex-separated toilets for since 2003. After legislation passed, in 2004 a private vocational college in Chiang Mai Thailand gave 15 'kathoey' students the opportunity to use toilet facilities that were solely for them, referred to as 'pink lotus' public toilets. Alliance organizations in Thailand such as the Thai Transgender Alliance and the Transferral Association of Thailand were created to support kathoey people such as by helping create separate public toilet facilities.
United States
There are unisex toilets in some public spaces in the United States. Cooper Union of New York City, New York was the first college in the country to de-gender all of their campus bathrooms in 2015.
Despite this, transgender and gender nonconforming people are still sometimes subject to visual or verbal scrutiny; this is reinforced by the architectural design and heteronormative gendered codes of conduct that are still present within the US.
On the federal level, the US Department of Labor is in charge of workplace toilets, which means setting state guidelines through the Occupational Safety and Health Administration (OSHA). OSHA Recommends that any workplace single-user toilet be made all-gender. For non-work related public toilet guidelines, the Department of Health and Human Services governs regulations. The Equal Employment Opportunity Commission ("EEOC") has also played a role in interpreting federal statutes and enforcing them. Two statutes relevant to public toilets are Title VII (nondiscrimination in the workplace) and Title IX (nondiscrimination in educational opportunity based on sex).
Building codes may be adopted by statute or regulation. They may require sex-separation or they may require unisex toilets. New building codes usually do not apply retroactively. Thus, building owners may choose not to update existing features because it allows them to continue following the older building codes that govern those older features. These regulations are mostly based on the precedent created by original legislation. They sometimes also work to eliminate the longer wait time females often face by creating a ratio of more female toilets than male toilets, and provide more inclusive environments for people requiring assistance in the restroom or people with children of a different gender. Various private businesses such as Target have publicly committed to maintaining all gender restrooms in stores nationwide even when not mandated by local or state ordinances.
US local ordinances
In most jurisdictions, local governments have the ability to pass ordinances, so long as they do not conflict with state law. San Francisco (California), Philadelphia (Pennsylvania), Seattle (Washington), Washington (District of Columbia), Berkeley (California), Cathedral City (California), West Hollywood (California), Austin (Texas), Cleveland (Ohio), New York City, Denver (Colorado), and the US states of Vermont, New Mexico, New York State, Illinois, Rhode Island, Maine, and California - have passed measures mandating that single-occupancy toilets in public spaces be labeled as unisex (or gender-neutral). In 2022, California enacted legislation allowing cities to build multi-stall gender-neutral bathrooms. Additionally, the 2021 edition of the International Plumbing Code (in use by 35 states, Puerto Rico, Guam, and DC) will require the same as individual states adopt the new edition of the code.
Some examples for local or state ordinances regarding unisex public toilets (see also: bathroom bill):
The city council of Portland, Oregon passed an ordinance for "all-user restrooms" in 2015 which directed city bureaus to convert "single-user gender-specific restrooms" into "all-user restrooms" within six months.
On May 11, 2018, Vermont Governor Phil Scott signed a bill requiring all single-user public toilets to be unisex, effective July 1, 2018.
On September 29, 2022, California became the first state to allow cities to require multi-stall unisex restrooms in buildings which are either newly constructed or undergoing extensive renovation. This law was supported by the City Council of West Hollywood, California, which passed an ordinance to that effect on December 7, 2022.
The Human Rights Campaign, an LGBTQ advocacy group, recommends that employers grant access, and use, to public toilets according to an employee's "full time gender presentation", and provides a list of recommendations on achieving this.
Portugal
In Portugal, some schools are adopting gender-neutral bathrooms and changing rooms as part of inclusive initiatives. The "Escola às Cores" project was implemented at Escola Básica Frei João in Vila do Conde, introducing individual bathrooms and changing rooms without gender identification. This change aimed to create a safe environment for trans students and also benefited those with other needs, such as health issues or home conditions that hindered proper hygiene. The initiative was successful and did not generate problems, emphasizing the importance of inclusive measures.
Other schools, like a private school in Lisbon and Escola António Arroio in Lisbon, have also adopted similar practices, promoting inclusive and respectful environments. However, not all stories are positive, with reports of challenges faced by some trans students in different school contexts.
The legislation passed in December of 2023 emphasized the need to ensure the well-being of all students in accessing bathrooms and changing rooms, encouraging necessary adaptations. The law did not abolish gender-segregated bathrooms, but there was misinformation that caused social panic. The legislation focused on respecting gender identity and allowing individuals to use self-attributed names in schools, without mandating mixed bathrooms. Despite this, the misunderstanding led to unnecessary concerns and fear within society. Psychologist Ana Silva warned of cases where children avoid using gendered restroom facilities due to fear of insults or aggression.
The Conselho de Ética e Ciências da Vida supports the existence of neutral bathrooms in schools, emphasizing the importance of respecting the right to privacy and intimacy.
History of sex-separated toilets
There are competing theories regarding how and why public toilets (or "bathrooms" in the United States) first became separated by sex in the United States and Europe.
Western sex-separation as a modern development
Public toilets, part of the sanitation system of ancient Rome, were shared by many demographics. These latrines housed long benches with holes accommodating multiple simultaneous users. There was no privacy between users, as using the facilities was considered a social activity. This communal multi-seater typology continued until the 1800s.
By the Middle Ages, public toilets became uncommon. People had the legal right and social custom to urinate and defecate wherever they pleased.
Sociologist Dara Blumenthal notes changing bodily habits, attitudes, and practices regarding hygiene starting in the 16th century, which eventually led to a resurgence of public toilets in the 19th century. Civility increasingly required the removal of waste product from contact with others. New instruction manuals, schoolbooks, and court regulations dictated what was appropriate. Some scholars argue that with increasingly strict prohibitions on bodily display and the emergence of a rigid ideology of gender, visual privacy and spatial separation of the sexes were introduced into public toilet design. They say that it was not until the Victorian era, starting in Great Britain, that sex separation began in public toilets.
The earliest known example of a western sex-separated public toilet was a temporary installation that occurred in 1739 at a Parisian ball. This involved chamber boxes in separate rooms with attendants guiding visitors to the appropriate location. According to sociologist and author Sheila Cavanagh, this was seen by the guests as "sort of a novelty - something eccentric and fun." She argues that this was done to accentuate sexual difference, and project that difference onto public space.
George Jennings, the sanitary engineer, introduced public toilets, which he called "monkey closets", to the Crystal Palace for The Great Exhibition of 1851. They included separate amenities for men and women, and were the first flush toilet facilities to introduce sex-separation to the activity. London's first public toilet facility opened the next year with only provisions for men, although other facilities opened for women at other venues.
Some scholars say the practice of maintaining separate toilets coincides with early 19th century moral ideology regarding the appropriate role and place for women in society. According to historian Terry Kogan, this constructed women as "inherently vulnerable and in need of protection" and men as "inherently predatory." This sexist view was put forward as a "scientific" fact, to curb the emergent women's rights movement. Legislators and policymakers acted on protecting "weaker" women by limiting their work hours, requiring rest periods during the day, and prohibiting certain jobs. This also included architectural solutions to "protect" women such as separate toilet facilities with "fainting" couches.
In the United States, Massachusetts was the first state to pass a law mandating sex-separated toilet facilities in 1887. It was titled "An Act To Secure Proper Sanitary Provisions in Factories and Workshops". The act called for suitable and separate toilets for women in the workplace. By 1920, this was mandated in 43 states. This development is believed to be a reflection of women entering the workforce.
Under another view, offered by W. Burlette Carter, sex-separation has long been the standard in the U.S. and Great Britain and most of the world where women's well-being was valued. She argues that when people used chamber pots, sex-separation could be achieved by placing the pot in a separated space. In single-use privies and similar spaces, that separation was achieved by allowing only one "sex" to use the space at a time. In multi-use spaces, it was achieved either through the same means or by separate spaces for the sexes. Very likely, the primary reasons for establishing these sex-separated spaces were safety and privacy for women and children. Concerns over undesired pregnancy and procreation were additional considerations. Some of these were related to concerns about rape or about moral views about how and when women should become pregnant (e.g., objections to premarital sex). Evidence also suggest that, in earlier centuries, when people sought to create unisex spaces for those who wanted or needed them, authorities resisted.
Carter argues that toilet separation by sex preceded 1739, and that in fact sex separated toilets have been a feature in multi-use spaces since their beginnings. Prior to the 1887 Massachusetts statute, across the United States and Europe at least, sex-separation was the norm already. For example, Massachusetts had statewide regulations that required sex-separation in particular venues such as schools before 1887. The earliest written reference to sex-separation in the United States may be from 1786. A traveler described bathers using a public spring called Healing Springs, in South Carolina. The bathers would hang Aprons from a tree to mark when the women were bathing and used Hats to mark when the men were bathing. Within the culture of that time, this practice was tantamount to hanging "women" and "men" signs. Furthermore, ancient evidence, including art-work, confirms widespread use of sex-separation (or sex segregation), especially in multi-use spaces - therefore not limiting the concept to public toilets. The exceptions were where the spaces were intended for amorous purposes by opposite sex couples, where safety was considered not to be at risk, or where women were not valued by society.
Primary rationales of sex-separation
One theory argues there were four primary rationales for sex-segregated toilets as detailed by state statutes and related literature in the nineteenth century: sanitation, women's privacy, the protection of women's bodies, which were seen as weaker, and to protect social morality especially as it pertained to the nineteenth century ideology of separate spheres. Subsequently, other states in the US created similar laws, often by amending existing protective labor legislation. Forty-three states had passed similar legislation by 1920. Others argue that safety and privacy were the two main goals of sex-separation (although factors such as morality also played roles). In New York in 1886, for example, factory inspectors asked for separate toilets out of concerns of women who came to them complaining of sexual harassment. Others argued for complete space separation citing the pressure on women to engage in sexual behavior to keep their jobs. Authorities who cared about these issues were trying to respond to those concerns by mandating separation. Indeed, these laws were likely among the first anti-sexual harassment laws in the nation. Many victims in the workplace were afraid to press charges for fear of losing work.
Some scholars have tied toilet sex-separation to segregation based on race discrimination in the US. Advocates of this view argue that these approaches share a theme in which a warning is issued against the looming threats: violence and sexual assaults would increase. Some political activists have drawn on the commonality between public toilets being segregated formerly by race and still by sex. Others argue that while all discrimination has commonalities, this parallel does not account for historical sex separation within racial groups, such as the forced separation of African men and women on slave ships.
In prior cases where restrooms were separated by race as well as gender, white women have traditionally been given more amenities because they were white. This denial was a sign of discrimination against others based on race and/or poverty, and not automatically a sign of society assigning a lesser value to women in general. Men also experienced different treatment, not based on class, but based on race, with black men having less favorable facilities. There is historical evidence that authorities have enforced the norm of sex-separated facilities to resist attempts by sexual minorities to create safe spaces that reimagined sex and gender lines.
Society and culture
Developing countries
In both developed and developing countries, many of the organizations active in water, sanitation and hygiene (WASH) provision have asserted that separate toilets for boys and girls at school are very important to make girls feel comfortable and safe using the sanitation facilities at schools. For example, in 2018, UNESCO stated that single-sex toilets are needed to overcome girls' barriers to education. This concern could potentially apply to boys as well, especially if open urinals are maintained. As an alternative, some argue that unisex school toilets could be provided at schools in addition to facilities that are separated by gender (which is often the case already in the case of toilets for people with disabilities).
WaterAid is researching options of appropriate unisex public toilets in developing countries. In 2017, they stated that those kinds of gender-neutral/mixed-sex toilets, where people can access all toilets irrespective of their gender, is not recommended in contexts where it may increase the risk of violence against women or transgender people, or where it is deemed culturally inappropriate.
Some activists favor 'third gender' public toilets which would only be used by transgender people. The degree of agreement or disagreement on such issues is difficult to gauge. However, this is still being debated. Some advocates argue that it would reinforce stigma and result in people being banned from accessing the toilets of the gender they identify with. It has been argued that in some African countries where transgender people are being prosecuted, this option would likely bring no benefit at all to them.
In the case of India, it has been found that designing transgender-inclusive sanitation is more than just a technical issue: It requires a deeper examination of the role of caste, gender, and age within the transgender community. Using a toilet that explicitly broadcasts a transgender person's identity to others may not be desirable to all transgender persons.
Transgender and gender nonconforming people
Advocates argue that public toilets and sanitation facilities have historically not met the needs of the LGBTI communities. They maintain that this is an issue with respect to the human right to water and sanitation and also from the perspective of the Sustainable Development Goal 6, which aim for universal access to sanitation and their vision of gender equality. All-gender public toilets are intended to ensure that toilets are fully accessible to all members of society.
Transgender and gender non-conforming persons are at a high risk of violence without access to gender-neutral bathrooms (see: trans bashing). They are often be subject to embarrassment, harassment, even assault or arrest, by others offended by the presence of a person they interpret as being of a different sex than themselves. It has been argued that walking into a toilet separated by sex requires people to self-separate and that some transgender people report being challenged on what public toilet they choose to use and subsequently "do their best to forego use of public toilets altogether". Providing unisex toilets can eliminate discrimination and harassment for people who may be perceived to be in the "wrong" toilet.
A 2015 study by the National Center for Transgender Equality found that 59% of transgender American avoided using public facilities for fear of confrontation. This landmark study, which included 27,715 respondents, found that 24% of respondents had their presence in the restroom questioned, 12% had experienced verbal harassment, physical assault, or sexual assault when attempting to use the restroom, and 9% were denied access entirely. Several studies have found that preventing transgender people from using public toilets has negative mental health impacts, leading to a higher risk of suicide. Without gender-neutral facilities, many people are unable to fulfill a basic need.
Hate crimes have taken place following transgender people using a bathroom. Alexa Negrón Luciano of Puerto Rico was shot and killed just hours after being reported to police for using a women's bathroom. Hate speech and gun shots can be heard in a video of the killing, causing investigators to treat this incident as motivated by transphobia. There have been a number of incidents covered by the news of transgender people being denied access, being forced to leave after appearing to have used the "wrong" bathroom, being made to use a bathroom that does not align with their identity, being harassed, being beaten, and being arrested.
In the early twenty-first century, with increased coverage of the transgender community, there have been some initiatives calling for unisex public toilets, instead of only male and female ones, to better accommodate genderqueer individuals. Sex-separation of public toilets began gaining traction as a controversial issue in US politics in 2010. This has become an increasingly contentious issue, as shown in the battles over North Carolina's 2016 Public Facilities Privacy & Security Act, among other bathroom bills. Several groups and organizations, whether in person or online, exist in order to combat attitudes and bills that oppose transgender individuals. For instance, the Transgender Law Center's "Peeing in Peace" is a pamphlet that serves as a resource guide full of information on harassment, safe public toilet campaigns and legal information.
While transgender public toilet usage has been labelled by many as a moral panic, the ongoing discourse continues to have significant impacts on this group.
Criticism
Some opponents of unisex public toilets argue that eliminating sex-separation entirely or identifying unisex spaces as the norm is not inclusive to women. They believe that women and children are more likely to be harassed and sexually assaulted there compared to sex-segregated public toilets. Safety in public toilets remains a serious issue for women. The recording of women in private spaces without their consent is also an issue.
Supporters of single-sex toilets point to the specific needs of women, such as menstrual hygiene, and argue that these require sex-segregation in public toilets, for reasons of personal comfort and privacy, and argue that this is especially true for teenage girls. Other concerns include that unisex toilets may be avoided by women, leading to both discomfort to women and wasting funds. Supporters of sex-segregated toilets argue that both males and females may feel "awkward" having to share a toilet with the opposite sex. A publication in 2018 argued that the scholarship on the history of sex-separation is flawed and places too much emphasis on the negative sides of sex separation in public toilets for women, ignoring aspects of safety for women from sexual harassment. It says these false narratives should be corrected and there is also a need for more innovative solutions.
Some women's groups, have opposed making unisex toilets the norm, based on safety concerns for most women and a need for safe spaces. Groups like WomansPlaceUK have led a charge to secure "safe" spaces for women, arguing that sexual harassment dangers would be increased for women. They assert that they affirm the existence of transgender people and their right to protection but that women's rights, as they see them, must also be recognized. In this respect, debate has centred around UK proposals to amend the Gender Recognition Act to change the process of obtaining a Gender Recognition Certificate to one of self-identification. Supporters of unisex spaces and access by self-declaration have rejected these claims. In the UK, trans people have for years been legally able to use the facilities that accord with their gender identity.
Statistics show no reports of transgender people attacking women. There has been no link between trans-inclusive policies and bathroom safety. A study conducted by the UCLA School of Law's Williams Institute found no significant change in the number of crimes since the passage of various laws that enable transgender public toilet usage. However, the primary issue at stake with communal unisex restrooms is not about the presence of transgender people but about the discomfort and lack of safety that women and girls could experience in having to share these restrooms with cisgender males.
Some religious groups have opposed unisex public toilets on the basis of morality. In 2017, a conservative Christian faith group leader in Texas has compared the introduction of unisex toilets with the abolition of Bible reading in state schools. However, there is energy for and against new bathroom bills by various groups of Christians.
In Germany, a member of the German right-wing party Alternative für Deutschland (AfD) regards the unisex toilet as a danger for German women and relates it to sexual assaults by "criminal foreigners".
Protests and opposition
Backlash has sometimes occurred when unisex public toilets have been implemented without wide public embrace. After backlash, and complaints from women, the Barbican Centre in the UK was required to reconsider its original design. They later issued a statement promising that, in addition to unisex public toilets, they would keep sex-separated toilets as well. In Los Angeles in 2016, there were violent clashes between supporters and opponents of toilets. Students, who attended the school with unisex toilets, confronted the adult protestors who had been outside the school with signs and horns. In Germany in 2018, the newly installed unisex toilets at Bielefeld University have repeatedly been vandalized. In Toronto, also in 2018, people complained about a unisex washrooms in a mall. In May 2021, The Daily Telegraph reported that Robert Jenrick, the communities secretary, was planning to ban unisex toilets in public buildings in order to "maintain safeguards that protect women". In the UK, the group Resisters plastered stickers all over the UK to protest what they called the confiscation of women's spaces. The stickers were in the shape of a penis and stated, "Women Don't Have Penises." A number of local women's groups referred to the behaviour as insulting to transgender persons and hate speech.
See also
Bathroom bill - legislation about public toilets in the United States
Female urination device
Gender apartheid
Human right to water and sanitation
Potty parity
Sanitation
Unisex changing rooms
References
External links
Directory of gender neutral toilets
Searchable database of accessible restroom locations
Queens University – Gender Neutral Washroom Policy
Canada.com – A revo-loo-tion on the UBC campus
Bathrooms
Building codes
Caregiving
Gender equality
Public toilets
Restrooms in the United States
Sex segregation
Transgender law | Unisex public toilet | Engineering | 8,537 |
3,771,867 | https://en.wikipedia.org/wiki/Type%20enforcement | The concept of type enforcement (TE), in the field of information technology, is an access control mechanism for regulating access in computer systems. Implementing TE gives priority to mandatory access control (MAC) over discretionary access control (DAC). Access clearance is first given to a subject (e.g. process) accessing objects (e.g. files, records, messages) based on rules defined in an attached security context. A security context in a domain is defined by a domain security policy. In the Linux security module (LSM) in SELinux, the security context is an extended attribute. Type enforcement implementation is a prerequisite for MAC, and a first step before multilevel security (MLS) or its replacement multi categories security (MCS). It is a complement of role-based access control (RBAC).
Control
Type enforcement implies fine-grained control over the operating system, not only to have control over process execution, but also over domain transition or authorization scheme. This is why it is best implemented as a kernel module, as is the case with SELinux. Using type enforcement is a way to implement the FLASK architecture.
Access
Using type enforcement, users may (as in Microsoft Active Directory) or may not (as in SELinux) be associated with a Kerberos realm, although the original type enforcement model implies so. It is always necessary to define a TE access matrix containing rules about clearance granted to a given security context, or subject's rights over objects according to an authorization scheme.
Security
Practically, type enforcement evaluates a set of rules from the source security context of a subject, against a set of rules from the target security context of the object. A clearance decision occurs depending on the TE access description (matrix). Then, DAC or other access control mechanisms (MLS / MCS, ...) apply.
History
Type enforcement was introduced in the Secure Ada Target architecture in the late 1980s with a full implementation developed in the Logical Coprocessing Kernel (LOCK) system. The Sidewinder Internet Firewall was implemented on a custom version of Unix that incorporated type enforcement.
A variant called domain type enforcement was developed in the Trusted MACH system.
The original type enforcement model stated that labels should be attached to subject and object: a “domain label” for a subject and a “type label” for an object. This implementation mechanism was improved by the FLASK architecture, substituting complex structures and implicit relationship. Also, the original TE access matrix was extended to other structures: lattice-based, history-based, environment-based, policy logic... This is a matter of implementation of TE by the various operating systems. In SELinux, TE implementation does not internally distinguish TE-domain from TE-types. It should be considered a weakness of TE original model to specify detailed implementation aspects such as labels and matrix, especially using the terms “domain” and “types” which have other, more generic, widely accepted meanings.
References
P. A. Loscocco, S. D. Smalley, P. A. Muckelbauer, R. C. Taylor, S. J. Turner, and J. F. Farrell. The Inevitability of Failure: The Flawed Assumption of Security in Modern Computing Environments. In Proceedings of the 21st National Information Systems Security Conference, pages 303–314, October 1998.
L. Badger, D. F. Sterne, D. L. Sherman, K. M. Walker and S. A. Haghighat, A Domain and Type Enforcement UNIX Prototype, In Proceedings of the 5th USENIX UNIX Security Symposium, June 1995.
W. E. Boebert and R. Y. Kain, A Practical Alternative to Hierarchical Integrity Policies, In Proceedings of the 8th National Computer Security Conference, page 18, 1985.
LOCK - A trusted computing system
Operating system security
Computer security models | Type enforcement | Engineering | 798 |
3,122,083 | https://en.wikipedia.org/wiki/Four%20Happiness%20Boys | The image of the Four Happiness Boys is believed to have begun during the Ming Dynasty (1368–1644) by a child prodigy by the name of Jie Jin.
By the age of five, this remarkable child had studied and mastered the ancient Chinese ‘Four Books’ and the ‘Five Classics' and soon made his way into formal studies alongside other renowned Chinese scholars of the period. The "Four Happiness Boys" is the ancient Chinese image or drawing of two interconnected boys to create the illusion of four laughing boys lying in four directions. The picture symbolizes ‘four happiness joined together’, which basically were: (a) a wedding night, (b)passing the imperial exams, (c) running into a friend in a faraway place, and (d) rain after a long drought – instances all considered to be among life's major fortunes in ancient China.
To this day, this image continues to be painted, drawn or cast in many materials including bronze, brass, and porcelain and is often given as a symbolic wedding gift for an abundant marriage, many generations of children, and good fortune and happiness.
See also
He-He er xian
Chinese numismatic charm
References
Chinese culture
Chinese iconography
Visual motifs | Four Happiness Boys | Mathematics | 248 |
67,946,474 | https://en.wikipedia.org/wiki/Psilocybe%20ruiliensis | Psilocybe ruiliensis is a species of psilocybin mushroom in the family Hymenogastraceae. Described as new to science in 2016, it is found in Yunnan province of southwest China. The species epithet, ruiliensis, is a reference to the location Ruili where the type collections were found. The type specimens were growing solitary to scattered in grasslands in which cows and horses had previously grazed.
Description
Cap: in diameter; conic to almost plane, with or without umbo or small acutely papillate at the disk; brownish-yellow (often with reddish tinge); hygrophanous and translucently striate when moist, watery brown when wet; sometimes bruising blue when damaged or mature; cortinate white veil and sometimes small scales when young.
Gills: Yellowish or beige when young, chocolate brown in age (gray-purple or purple tinge), with adnate to subsinuate or adnexed attachment; edges serrulate and slightly wavy.
Spores: Brown with purple tinge (in water); ellipsoid to subhexagonal; smooth and slightly thick-walled, sometimes containing 1–2 oil drops; 9–11 by 6–7.5 μm.
Stipe: long, thick; yellow-white to brownish, sometimes bruising bluish when damaged; central or occasionally slightly eccentric; fibrillose; hollow; annulus absent; equal to slightly enlarged bulbous base. Stem base with rhizomorphic white mycelium.
Odor: Slightly grassy.
Microscopic features: Larger hexagonal and subrhomboid basidiospores (9.6–12.0 by 6.4–8.4 μm); ventricose-lageniform cheilocystidia and pleurocystidia.
See also
List of psilocybin mushrooms
List of Psilocybe species
References
ruiliensis
Fungi described in 2016
Fungi of China
Fungus species | Psilocybe ruiliensis | Biology | 410 |
61,437,976 | https://en.wikipedia.org/wiki/Flight%20of%20Five%20Locks | The Flight of Five Locks on the Erie Canal in Lockport, New York is a staircase lock constructed to lift or lower a canal boat over the Niagara Escarpment in five stages.
The locks are part of the Erie Canalway National Heritage Corridor.
In Stairway to Empire: Lockport, the Erie Canal, and the Shaping of America, (SUNY Press, 2009), historian Patrick McGreevy details the construction of the locks. The "Stairway" of McGreeevy's title is the Flight of Five Locks.
History
To carry the canal across the Niagara Escarpment, the engineers built a five-step staircase lock.
Restoration
The restored locks reopened in .
References
Staircase locks
Erie Canal
Historic Civil Engineering Landmarks | Flight of Five Locks | Engineering | 147 |
51,724,045 | https://en.wikipedia.org/wiki/NGC%20241 | NGC 241 is an open cluster located in the constellation Tucana. It is located within the Small Magellanic Cloud. It was discovered on April 11, 1834, by John Herschel.
References
0241
Open clusters
Tucana
Small Magellanic Cloud | NGC 241 | Astronomy | 52 |
7,999,570 | https://en.wikipedia.org/wiki/ORFeome | In molecular genetics, an ORFeome refers to the complete set of open reading frames (ORFs) in a genome. The term may also be used to describe a set of cloned ORFs. ORFs correspond to the protein coding sequences (CDS) of genes. ORFs can be found in genome sequences by computer programs such as GENSCAN and then amplified by PCR. While this is relatively trivial in bacteria the problem is non-trivial in eukaryotic genomes because of the presence of introns and exons as well as splice variants.
Use in research
The usage of complete ORFeomes reflects a new trend in biology that can be succinctly summarized as omics. ORFeomes are used for the study of protein-protein interactions, protein microarrays, the study of antigens, and other fields of study.
Cloned ORFeomes
Complete ORF sets have been cloned for a number of organisms including Brucella melitensis,
Chlamydia pneumoniae,
Escherichia coli,
Neisseria gonorrhoeae,
Pseudomonas aeruginosa, Schizosaccharomyces pombe, Staphylococcus aureus
and human herpesviruses
A partial human ORFeome has also been produced.
References
Molecular genetics
Genomics | ORFeome | Chemistry,Biology | 274 |
19,348,510 | https://en.wikipedia.org/wiki/Campshire | The campshires are the stretches of land between the quay and road on both the north and south quays in Dublin. They are so named because various British military regiments, such as the Gloucestershires or Leicestershires, would camp there before setting off or returning from overseas, making 'campshire' a portmanteau of 'camp' and '-shire'.
It is not clear when the word was first used, but it must date to the First World War or earlier. The term appears in a 1957 issue of The Irish Times.
Before the Dublin Port facilities moved down river, this was the area of the Dublin quays where ships were loaded and unloaded. As a result, the area had a number of storage warehouses and travelling cranes.
The campshires were renewed and renovated by the now-defunct Dublin Docklands Development Authority between 2000 and 2005, adding walkways and cycleways on both sides of the river Liffey, including parts of the Sutton to Sandycove project. A number of buildings on the campshires were also subject to renovations during the first decade of the 21st century.
Notes
Coastal construction
Port infrastructure
Docks (maritime)
Quays in Dublin (city)
Dublin Docklands | Campshire | Engineering | 245 |
11,350,199 | https://en.wikipedia.org/wiki/Box%20%28theatre%29 | In a theatre, a box, loge, or opera box is a small, separated seating area in the auditorium or audience for a limited number of people for private viewing of a performance or event.
Boxes are typically placed immediately to the front, side and above the level of the stage. They are separate rooms with an open viewing area which typically seat five people or fewer. Usually all the seats in a box are taken by members of a single group of people. A state box or royal box is sometimes provided for dignitaries.
In theatres without box seating the loge can refer to a separate section at the front of the balcony.
Sports venues such as stadiums and racetracks also have royal boxes or enclosures, for example at the All England Club and Ascot Racecourse, where access is limited to royal families or other distinguished personalities. In other countries, sports venues have luxury boxes also known as skyboxes, where access is open to anyone who can afford tickets, sometimes bought by companies.
History
Opera boxes were a status of wealth and high social standing in the 18th and 19th centuries. The Opera became a place not only for enjoying art and music but also for displaying wealth and social status.The epitome of extravagance could be viewed in the art, fashions and behaviors at the Opera.
See also
Balcony
The gods (theatrical)
Loggia
References
Parts of a theatre | Box (theatre) | Technology | 278 |
67,006,138 | https://en.wikipedia.org/wiki/Kepler-635 | Kepler-635 (KOI-649, KIC 5613330) is an F7V star with an extrasolar planetary system discovered by the Kepler space telescope. The star was first thought to be variable, but later determined to be static.
Planetary system
The planetary system contains one confirmed planet and was first detected by the Kepler space telescope.
References
F-type main-sequence stars
649
Lyra
J19190557+4048026 | Kepler-635 | Astronomy | 96 |
5,704,711 | https://en.wikipedia.org/wiki/Thiosemicarbazone | A thiosemicarbazone is an organosulfur compound with the formula H2NC(S)NHN=CR2. Many variations exist, including those where some or all of the NH centers are substituted by organic groups. Thiosemicarbazones are usually produced by condensation of a thiosemicarbazide with an aldehyde or ketone:
H2NC(S)NHNH2 + O=CR2 → H2NC(S)NHN=CR2 + H2O
In terms of their chemical structures, the CSN3 core atoms are coplanar.
Occurrence and applications
Some thiosemicarbazones have medicinal properties, e.g. the antiviral metisazone and the antibiotic thioacetazone. Thiosemicarbazones are also widely used as ligands in coordination chemistry. The affinity of thiosemicarbazones for metal ions is exploited in controlling iron overload.
References
Functional groups | Thiosemicarbazone | Chemistry | 209 |
8,113,127 | https://en.wikipedia.org/wiki/Relational%20Model/Tasmania | Relational Model/Tasmania (RM/T) was published by Edgar F. Codd in 1979 and is the name given to a number of extensions to his original relational model (RM) published in 1970. The overall goal of the RM/T was to define some fundamental semantic units, at "atomic" and "molecular" levels, for data modelling. Codd writes: "the result is a model with a richer variety of objects than the original relational model, additional insert-update-delete rules and some additional operators that make the algebra more powerful."
RM history
Between 1968 and 1988 Codd published over 30 papers on the relational model (RM) - the most famous of which is his 1970 paper. Up to 1978 the papers describe RM Version 1 (RM/V1). In early 1979 Codd first presented some new ideas, called RM/T ('T' for Tasmania), at an invited talk for the Australian Computer Science Conference in Hobart, Tasmania. Later that year the ACM journal published a paper on RM/T, in which Codd acknowledges the influence of Schmid & Swensen (1975) and Wiederhold (1977).
A later version of RM/T (we shall call it here "RM/D") was described by Chris Date in Date (1983) in which Date and Codd improved and refined RM/T, adding an entity type called designative. Although Codd writes nothing about this new type, Date offers a rationale in Date (1983, page 262). Date revised this 1983 article in Date (1995), which additionally compares the RM/T model with the E/R model.
Following a disappointing uptake of RM/T by the database industry, Codd decided to introduce the RM/T model more gradually. He planned to release a sequence of RM versions: RM/V2, RM/V3 etc. each time progressively including some of the ideas of the original RM/T into the new version. Perhaps this explains why there is no obvious mapping of concepts between RM/T and RM/V2. For example, there is no reference to associative or designative entity types in Codd's 1990 book that defines RM/V2. On the other hand, the book extends and builds on the existing body of query language issues, many of which were addressed by Codd in several papers throughout the 1980s.
Summary of RM/T
Introducing some of the new concepts of RM/T:
Surrogates A surrogate is a unique value assigned to each entity. If two relations use the same surrogate value then they represent the same entity in the modelled universe. The surrogate value can be any unique string or number but cannot be assigned or changed by the database user. For example, a SQL SEQUENCE is often used to generate numerical surrogate values. This use of surrogate was first introduced in Hall, Owlett and Todd in 1976.
Entities and Nonentities An entity is some thing in the modelled universe and is typically identified by a surrogate. A nonentity is some thing that is not an entity and does not have its own identifying surrogate. An independent entity has its own surrogate. A dependent entity has a surrogate but it belongs to another entity, i.e. the surrogate is a foreign key.
Atomic Semantics The RM/T addresses atomic semantics by describing how the original RM relation can be used to describe entities with attributes. An entity is represented as an Entity-relation or E-relation and its attributes (or immediate properties) are stored in separate Property-relations or P-relations. Each E-relation shares its surrogate with the associated P-relations.
E-relations Mark the existence of an entity. An E-relation is a relation (table) storing only the surrogates for a particular entity type. A surrogate value entered into the E-relation table implies the corresponding existence of an entity of that type in the modelled world. For example, the E-relation "Employee" is a table containing the surrogates of all entities of type Employee.
P-relations Store the attribute values of an entity. A P-relation is a relation (table) storing the surrogate and one or more attributes of an entity. The surrogate value of a P-relation is that of the corresponding E-relation; it plays the role (K-role) of the primary key for that P-relation. For example, the P-relation "Employee_Number" is a table with two columns: one containing the surrogate value of the "Employee" E-relation, the other containing the employee number.
Note that by performing an OUTER NATURAL JOIN on the RM/T "Employee" E-relation and "Employee_Person" P-relation we can construct the RM/V1 "Employee" relation. This illustrates why the E-relation and P-relation concepts of RM/T are more atomic than the relation concept of RM/V1.
Molecular Semantics The RM/T addresses molecular semantics by taking the original RM and categorising the relations into several entity types, increasing the information captured by the semantic data model. However Codd does not define a notation for diagramming his new semantics. Each entity may play several roles at once and thus belong to one or more of the following entity types:
Characteristic – subordinate entities that describe kernel entities.
Associative – superordinate entities that interrelate kernel entities.
Kernel – entities that are neither characteristic or associative.
Codd goes on to introduce subtyping of entities, giving yet another qualifier for entities:
Inner – entities that are not subtypes of another entity.
Hence Codd speaks of inner kernel and inner associative entities.
The following definition is based on the RM/D model in Date (1983); it does not appear in Codd (1979):
Designative – entities that contain a designation. A designative entity is at the many end of a one-to-many relationship between two independent entities. For example, a writer may write many books, hence a one-to-many relationship between writer and book entities; the book is the designative entity because it contains a designation (or designative reference) to the writer - namely the primary key of the writer entity. Note that an associative entity contains at least two designations. For example, we can regard a booking as either an entity that associates a person with a flight, or as an entity that designates a person and designates a flight. Hence a designative entity must contain at least one designation whereas an associative entity must contain at least two designations.
Associations These are what we might otherwise call relationships between entities or non-entities.
The value E-null is used when deleteting entities from the RM/T model; all associations that have surrogates referring to a non-existing entity are assigned the value E-null, meaning the entity is unknown.
Associative Entity and Nonentity Association An associative entity is an entity that represents an association between two independent entities; the associative entity is an entity in itself because it has a surrogate. A nonentity association is similar to an associative entity however it has no surrogate. This lack of a surrogate stops the nonentity association from having, for example, any descriptive characteristic entities.
Directed Graph Relations Several directed graph relations are defined to capture further semantic features of the RM/T model. These graphs are named as follows:
PG-relation (Property Graph) stores property relationships
CG-relation (Characteristic Graph) stores characteristic relationships
AG-relation (Association Graph) stores association relationships
UGI-relation (Unconditional Generalisation by Inclusion) stores generalisation by inclusion relationships
AGI-relation (Alternative Generalisation by Inclusion) stores generalisation by alternative relationships
US-relation (Unconditional Successor) stores unconditional successor relationships
AS-relation (Alternative Successor) stores alternative successor relationships
KG-relation (Cover Membership) stores cover membership relationships
UP-relation (Unconditional Precedence) stores unconditional succession of event relationships
AP-relation (Alternative Precedence) stores alternative succession of event relationships
RM/T Catalog The Catalog is a meta-model storing the descriptions of the relations themselves. The RM/T Catalog comprises the following relations:
CATR (R-surrogate, relname, RelType) describes relations
CATRA (RA-surrogate, R-surrogate, A-surrogate) relates relations and attributes
CATA (A-surrogate, attname, UserKey) describes attributes
CATAD (AD-surrogate, A-surrogate, D-surrogate) relates attributes and domains
CATD (D-surrogate, domname, VType, Ordering) describes domains
CATC (C-surrogate, pername) describes categories
CATRC (RC-surrogate, R-surrogate, C-surrogate) relates relations and categories
where
relname is the textual name of a relation. e.g. "Address"
attname is the textual name of an attribute. e.g. "Street"
domname is the textual name of a domain. e.g. "Salary"
pername is the category label (from the PER-domain)
RN-domain is the domain of all relnames in the database
PER-domain is the domain of all category labels
E-domain is the domain of all surrogates in the database
E-attribute is any attribute that plays the role of a surrogate (from the E-domain)
E-null is the "entity unknown" surrogate (from the E-domain)
R-surrogate is the relation surrogate (from the E-domain)
A-surrogate is the attribute surrogate (from the E-domain)
D-surrogate is the domain surrogate (from the E-domain)
C-surrogate is the category label surrogate (from the E-domain)
RA-surrogate is the relation-attribute surrogate (from the E-domain)
AD-surrogate is the attribute-domain surrogate (from the E-domain)
RC-surrogate is the relation-category-label surrogate (from the E-domain)
RelType is the type of object represented by the relation
UserKey shows whether the attribute participates in a user-defined key
VType is the syntactic type of the value
Ordering shows whether the operator > is applicable between values of the domain
Operators Numerous operators are defined on names, sets and graphs. See Codd's 1979 paper for details.
RM/T today
There is little mention of RM/T today and no articles have appeared recently. Peckam and Maryanski (1988) wrote about RM/T in their study of semantic data models. Codd published his book in 1990 but wrote nothing more about RM/T. RM/V1 and RM/V2 have a chapter each in Date and Darwen (1992) and the Date (1983) article was updated in (1995) and now contains a long overdue comparison of the E/R model and RM/T. Date's most recent reflections can be found on the Web at Date (1999), The Database Relational Model (2001) and Date on RM/T (2003).
RM/T contributed to the body of knowledge called semantic data modeling and semantic object modeling and continues to influence new data modellers. See the paper by Hammer and McLeod (1981), the book by Knoenke (2001) and implementation by Grabczewski et alia (2004).
References
Further reading
; a useful survey that includes RM/T.
Data modeling | Relational Model/Tasmania | Engineering | 2,399 |
2,772,805 | https://en.wikipedia.org/wiki/Lake%20Monoun | Lake Monoun is a crater lake (maar) in West Province, Cameroon, that lies in the Oku Volcanic Field. On August 15, 1984, a limnic eruption occurred at the lake, which resulted in the release of a large amount of carbon dioxide () that killed 37 people. At first, the deaths remained unexplained, and causes such as terrorism were suspected. Further investigation and a similar event two years later at Lake Nyos led to the currently accepted explanation.
Disaster
Several people reported hearing a loud noise on August 15, 1984, around 22:30. A gas cloud reportedly emanated from a crater in the eastern part of the lake. The resulting deaths of 37 residents in a low-lying area are believed to have occurred between 03:00 and dawn. The victims were said to have skin burns, which reports later clarified as "skin damage" such as discoloration. Survivors reported that the whitish, smoke-like cloud smelled bitter and acidic. Vegetation was flattened around the eastern part of the lake, probably by a large wave of up to height.
Although Lake Monoun is near the center of a volcanic field that includes at least 34 recent craters, the subsequent investigation found that the event was not caused by an eruption or sudden ejection of volcanic gas from the lake. Rather, emission of carbon dioxide in a limnic eruption is thought to be to blame. The cloud's smell and skin damage to victims were not fully explained. Some theories attribute the skin problems to a combination of preexisting conditions and routine postmortem effects like livor mortis, another medical interpretation says the body's metabolic rate was reduced inducing a severely restricted circulation in capillary vessels of the skin, resulting in necrosis, although there is no clear consensus.
Among the victims were some of the riders in a truck carrying twelve people. The truck's engine stopped working as it became starved of oxygen, and the people inside the truck got out and were killed. Two people sitting on top of the truck survived, because their elevated position allowed them to breathe – carbon dioxide is heavier than air (oxygen and nitrogen) which causes it to stay close to the ground.
Two years later, on 21 August 1986, a similar and much more deadly event occurred at Lake Nyos, about north-northwest, killing 1,746 people and more than 3,000 livestock. Along with Lake Nyos and Lake Kivu, Lake Monoun is one of three lakes in the world known to have high concentrations of gas dissolved deep below the surface and which have the right conditions for a limnic eruption.
Degassing
In March and April 1992 preliminary test were conducted at Lake Monoun using the gas lift method as known in the petroleum industry. Initially a pump (or preferably a compressed gas injection) is needed to pull water from the bottom, but as carbon dioxide begins to come out of solution it creates buoyancy in the water in the pipes, allowing a self-sustaining process without the need for external energy supply.
Due to the very limited funds for the project and construction basically by hand, the solution was the use of high-density polyethylene (HDPE) pipes. The material has a specific gravity of 0.96 kg/L which means an almost neutral buoyancy in water. The HDPE plastic is flexible, not brittle, and resistive to chemical and weathering alteration as proven material for natural gas distribution networks.
The pipe could be easily soldered electrically in the field from standard segments, and deployed with just the help of a few rubber boats plus floats. With some ballast, the pipe hangs freely from an anchored raft like a pendulum.
Unfortunately, the -rich, oxygen-depleted water from the depth is a challenge for steel fittings: Corrosion occurred and formed siderite which removed iron from the steel.
In February 2003, a venting pipe was inserted into the lake, in an effort to prevent the disaster from recurring. In the initial degassing phase, an fountain developed from the water tapped at depth. However, a study found in 2005 that gas was not being removed from the lake quickly enough to ensure that the disaster could never happen again. It was recommended to lower the inlet of the existing pipe down to and the addition of a second pipe in order to release more carbon dioxide. On the other hand, the deep lake water is rich in iron(II) ions, which after a while transforms into limonite. As the lake is a fishing ground for local villagers, the effect of a higher iron intake rate in the upper water layer on fishlife needed consideration before scaling up the degassing rate.
In December 2013, the degassing pipe was upgraded with a small solar-power driven rotary pump, since it had lost its self-lift capability due to the bubbling effect in the riser as a significant amount of had been removed from the bottom layers. The new system is able to lift of bottom water to the surface per day. That degassing capability is unfortunately less than the natural inflow of -rich water, therefore two more of these solar pumps are needed to avoid a long-term build up of higher and dangerous levels of in the stratified water levels.
See also
Mazuku
Meromictic lake
Lake Kivu
Limnic eruption
References
External links
The Lake Nyos and Monoun Degassing Project
Killer lakes in Cameroon may strike again
Volcanic Lakes and Gas Releases – Reports from the investigation of the disaster
BBC News 27 Sep 2005: Action needed on deadly lakes
Mechanics of the switching on of the trigger mechanism of limnological catastrophes – Latvian research by Nataliya Anatolievna Solodovnik and Anatoliy Borisovich Solodovnik
Lakes of Cameroon
West Region (Cameroon)
20th-century volcanic events
Mbéré Rift Valley
Rift volcanoes
Volcanoes of Cameroon
Maars of Cameroon
Gas explosions
Volcanic crater lakes
Meromictic lakes
Explosions in Cameroon
Explosions in 1984
August 1984 events in Africa
1984 in Cameroon
Natural disasters in Cameroon
Limnically active lakes | Lake Monoun | Chemistry | 1,223 |
5,924,450 | https://en.wikipedia.org/wiki/Subcellular%20localization | The cells of eukaryotic organisms are elaborately subdivided into functionally-distinct membrane-bound compartments. Some major constituents of eukaryotic cells are: extracellular space, plasma membrane, cytoplasm, nucleus, mitochondria, Golgi apparatus, endoplasmic reticulum (ER), peroxisome, vacuoles, cytoskeleton, nucleoplasm, nucleolus, nuclear matrix and ribosomes.
Bacteria also have subcellular localizations that can be separated when the cell is fractionated. The most common localizations referred to include the cytoplasm, the cytoplasmic membrane (also referred to as the inner membrane in Gram-negative bacteria), the cell wall (which is usually thicker in Gram-positive bacteria) and the extracellular environment. The cytoplasm, the cytoplasmic membrane and the cell wall are subcellular localizations, whereas the extracellular environment is clearly not. Most Gram-negative bacteria also contain an outer membrane and periplasmic space. Unlike eukaryotes, most bacteria contain no membrane-bound organelles, however there are some exceptions (i.e. magnetosomes).
Protein Subcellular Location Databases
The experimentally determined subcellular locations of proteins can be found in UniProtKB, Compartments, and in a few more specialized resources, such as the lactic acid bacterial secretome database.
There are also several subcellular location databases with computational predictions, such as the fungal secretome and subcellular proteome knowledgebase - version 2 (FunSecKB2), the plant secretome and subcellular proteome knowledgebase (PlantSecKB), MetazSecKB for protein subcellular locations of human and animals, and ProtSecKB for protein subcellular locations of all protists.
Proteome Analyst is a freely available web server and online toolkit for predicting protein subcellular localization.
See also
Protein targeting
Protein subcellular localization prediction.
References
Cell biology | Subcellular localization | Biology | 422 |
55,870,946 | https://en.wikipedia.org/wiki/Counterfeit%20illegal%20drug%20selling | Selling counterfeit illegal drugs is a crime in many U.S. states' legal codes and in the federal law of the United States. The fake drugs are sometimes termed as imitation controlled substances.
Relation to drug-related crimes
There is a low chance of law punishing fraud among illicit drug traders, however it is likely that informal social control among drug traders reduces the likelihood of fraud between illegal trade partners. For instance, getting robbed or losing a business contact may not justify dealer's increased profits for a short-term from fraudulent behavior.
Legal status
Selling counterfeit illicit drugs is illegal even if the substances used to make the imitation drug are not illegal on themselves. It is illegal to distribute or sell counterfeit fake drugs in many U.S. states including Nevada, Ohio, Illinois, Florida, Michigan and Massachusetts.
U.S. Federal Law
Selling counterfeit illicit drugs is illegal under the U.S. federal law. Relevant parts of the U.S. federal law include 21 U.S.C. Section 331 and 18 U.S. Code § 1001.
21 U.S.C. Section 331 makes it illegal to sell an adulterated or misbranded drug in interstate commerce.
18 U.S. Code § 1001 bans
falsifying, concealing or covering up a material fact;
making any materially false, fictitious or fraudulent statement or representation; or
making or using any false writing or document knowing that it contains materially false, fictitious or fraudulent statements.
Deaths
Europe
Amsterdam
On 25 November 2014 two British tourists aged 20 and 21 died in a hotel room in Amsterdam, after snorting white heroin that was sold as cocaine by a street dealer. The bodies were found less than a month after another British tourist died in similar circumstances. At least 17 other people have had medical treatment after taking the white heroin.
Sweden
Nine deaths occurred in Sweden during 2010–11 relating to use of Krypton, a mixture of kratom, caffeine and O-desmethyltramadol, a metabolite of the opioid analgesic tramadol.
See also
Unclean hands
References
Causes of death
Crime
Drug control law
Drug policy
History of drug control
Illegal drug trade | Counterfeit illegal drug selling | Chemistry | 449 |
34,494,696 | https://en.wikipedia.org/wiki/ShelXle | The program ShelXle is a graphical user interface for the structure refinement program SHELXL. ShelXle combines an editor with syntax highlighting for the SHELXL-associated (input) and (output) files with an interactive graphical display for visualization of a three-dimensional structure including the electron density (Fo) and difference density (Fo-Fc) maps.
Overview
ShelXle can display electron density maps like the macromolecular program Coot but is more intended for smaller molecules.
A number of excellent graphical user interfaces (GUIs) exist for small molecule crystal structure refinement with SHELX (e.g., WINGX, Olex2, XSEED, PLATON and SYSTEM-S, and the Bruker programs XP and XSHELL)
ShelXle is free software, distributed under the GNU LGPL. It is available from the ShelXle website or from SourceForge. Binaries are available for Windows, macOS and the Linux distributions SuSE, Debian and Ubuntu.
The Windows binary is distributed with the NSIS Installer.
Features
Editor featuring syntax highlighting and code completion for the SHELX instructions.
Clicking on an atom in the structure view sets the text cursor to the line that contains this atom.
Locating atoms in structure view from the editor.
Rename mode with support of residues and disordered parts and free variables.
Program architecture
ShelXle uses the Qt (framework). It is written entirely in C++ and does not use any scripting language. For the refinement it calls the external binary of SHELXL which might also be SHELXH, SHELXLMP from George M. Sheldrick or XL from Bruker.
SHELX
SHELX is developed by George M. Sheldrick since the late 1960s. Important releases are SHELX76 and SHELX97. It is still developed but releases are usually after ten years of testing.
Academic users can download the SHELX programs freely after registration.
External links
ShelXle web site
ShelXle support forum at xrayforum.co.uk
ShelXle at Sourceforge
References
Crystallography software
Molecular modelling software
Free science software | ShelXle | Chemistry,Materials_science | 478 |
60,361,363 | https://en.wikipedia.org/wiki/Algae%20DNA%20barcoding | DNA barcoding of algae is commonly used for species identification and phylogenetic studies. Algae form a phylogenetically heterogeneous group, meaning that the application of a single universal barcode/marker for species delimitation is unfeasible, thus different markers/barcodes are applied for this aim in different algal groups.
Diatoms
Diatom DNA barcoding is a method for taxonomical identification of diatoms even to species level. It is conducted using DNA or RNA followed by amplification and sequencing of specific, conserved regions in the diatom genome followed by taxonomic assignment.
One of the main challenges of identifying diatoms is that it is often collected as a mixture of diatoms from several species. DNA metabarcoding is the process of identifying the individual species from a mixed sample of environmental DNA (also called eDNA) which is DNA extracted straight from the environment such as in soil or water samples.
A newly applied method is diatom DNA metabarcoding which is used for ecological quality assessment of rivers and streams because of the specific response of diatoms to particular ecologic conditions. As species identification via morphology is relatively difficult and requires a lot of time and expertise, high-throughput sequencing (HTS) DNA metabarcoding enables taxonomic assignment and therefore identification for the complete sample regarding the group specific primers chosen for the previous DNA amplification.
Until now, several DNA markers have already been developed, mainly targeting the 18S rRNA. Using the V4 hypervariable region of the ribosomal small subunit DNA (SSU rDNA), DNA-based identification was found to be more efficient than the classical morphology-based approach. Other conserved regions in the genomes which are frequently used as marker genes are ribulose-1-5-bisphosphate carboxylase (rbcL), cytochrome oxidase I (cox1, COI), ITS and 28S. It has been shown repeatedly that the molecular data gained by diatom eDNA metabarcoding quite faithfully reflect the morphology-based biotic diatom indices and therefore provide a similar assessment of ecosystem status. In the meantime, diatoms are routinely used for the assessment of ecological quality in other freshwater ecosystems. Together with aquatic invertebrates they are considered as the best indicators of disturbance related to physical, chemical or biological conditions of watercourses. Numerous studies are using benthic diatoms for biomonitoring. Because no ideal diatom DNA barcode was found, it has been proposed that different markers are used for different purposes. Indeed, the highly variable cox1, ITS and 28S genes were considered more suitable for taxonomic studies, while more conserved 18S and rbcL genes seem more appropriate for biomonitoring.
Advantages
Applying the DNA barcoding concept to diatoms promises great potential to resolve the problem of inaccurate species identification and thus facilitate analyses of the biodiversity of environmental samples.
Molecular methods based on the NGS technology almost always leads to a higher number of identified taxa whose presence could subsequently be verified by light microscopy. Results of this study provides evidence that eDNA barcoding of diatoms is suitable for water quality assessment and could complement or improve traditional methods. Stoeck et al. also showed that eDNA barcoding provides a more insight into diatom diversity or other protist communities and therefore could be used for ecological projection of global diversity. Other studies showed different results. For example, inventories obtained from the molecular-based method were closer to those obtained by the morphology-based method when abundant species are in focus.
DNA metabarcoding can also increase the taxonomic resolution and comparability across geographic regions, which is often difficult using morphological characters only. Moreover, DNA-based identification allows extending the range of potential bioindicators, including the inconspicuous taxonomic groups that could be highly sensitive or tolerant to particular stressors. Indirectly, the molecular methods can also help filling the gaps in knowledge of species ecology, by increasing the number of samples processed coupled with a decrease in processing time (cost-effectiveness), as well as by increasing the accuracy and precision of correlation between species/MOTUs occurrence and environmental factors.
Challenges
Currently there is no consensus concerning methods for DNA preservation and isolation, the choice of DNA barcodes and PCR primers, nor agreement concerning the parameters of MOTU clustering and their taxonomic assignment. Sampling and molecular steps need to be standardize through development studies. One of the major limitation is the availability of reference barcodes for diatoms species. The reference database of bioindicator taxa is far from complete despite the constant efforts of numerous national barcoding initiatives a lot of species are still lacking barcode information. Furthermore, most existing metabarcoding data are only locally available and geographically scattered, which is hindering the development of globally useful tools. Visco et al. estimated that no more than 30% of European diatoms species are currently represented in reference databases. For example, there is an important lack for a number of species from the Fennoscandian communities (especially acidophilic diatoms, such as Eunotia incisa). It has also been shown that taxonomic identification with DNA barcoding is not accurate above species level, to discriminate varieties for example (reference missing).
Another well-known limitation of barcoding for taxonomic identification is the clustering method used before the taxonomic assignation: It often leads to massive loss of genetic information and the only reliable way to assess the effects of different clustering and different taxonomic assignation processes would be to compare the species list generated by different pipelines when using the same reference database. This has yet to be done for the variety of pipelines used in molecular assessment of diatom communities in Europe. Taxonomically validated databases, which includes accessible vouchers are also crucial for reliable taxa identification via NGS.
Additionally, primer bias is often found to be a major source of variation in barcoding and PCR primers efficiency can differ between diatoms species, i.e. some primers lead to a preferential amplification of one taxon over another.
The inference of abundance from metabarcoding data is considered as one of the most difficult issues in environmental use. The number of generated sequences by HTS does not directly correspond to the number of specimen or biomass and that different species can produce different amount of reads, (for example, due to differences in the chloroplast size with the rbcL marker). Vasselon et al. recently created a biovolume correction factor when using the rbcL marker. For example, Achnanthidium minutissimum has a small biovolume, and thus will generate less copies of the rbcL fragment (located in the chloroplast) than larger species. This correction factor, however, requires extensive calibration with each species own biovolume and has been tested only on a few species that far. Fluctuations of gene copy number for other markers, such as the 18S marker, does not seem to be species specific, but have not been tested yet.
Diatom target regions
Barcoding marker usually combine hypervariable regions of the genome (to allow the distinction between species) with very conserved region (to insure a specificity to the target organism). Several DNA markers, belonging to the nuclear, mitochondrial, and chloroplast genomes (rbcL, COI, ITS+5.8S, SSU, 18S...), have been designed and successfully used for diatoms identification with NGS.
18S and V4 subunit
The 18S gene region has been widely used as a marker in other protist groups and Jahn et al. were the first to test the 18S gene region for diatoms barcoding. Zimmerman et al. proposed a 390–410 bp long fragment of the 1800 bp long 18S rRNA gene locus as a barcode marker for the analysis of environmental samples with HTS. and discusses its use and limitations for diatom identification. This fragment includes the V4 subunit which is the largest and most complex of the highly variable regions within the 18S locus. They highlighted that this hypervariable region of the 18S gene have great potential for studying protist diversity at large scale but has limited efficiency to identification below species level or cryptic species.
rbcL
The rbcl gene is used for taxonomy studies (Trobajo et al. 2009) which benefits include that rarely any intragenomic variation and they are very easily aligned and compared. An open-access reference library, called R-Syst::diatom includes data for two barcodes (18S and rbcL). It is freely accessible through a website. Kermmarec et al. also successfully used the rbcL gene for ecological assessment of diatoms. The rbcL marker is also easily aligned and compared.
Moniz and Kaczmarska investigated the amplification success of the SSU, COI, and ITS2 markers and found that the 300 – 400 bp ITS-2 + 5.8S fragment provided the highest success rate of amplification and good species resolution. This marker was subsequently used to separate morphologically defined species with a success rate of 99.5%. Despite this amplification success, Zimmerman et al. criticised the use of ITS-2 due to intra-individual heterogeneity. It has been suggested that SSU or the rbcL (Mann et al., 2010) markers less heterogenous between individuals and therefore more beneficial when distinguishing between species.
Applications
Genetic tool for biomonitoring and bioassessment
Diatoms are routinely used as part of a suite of biomonitoring tools which must be monitored as part of the European Water Framework Directive. Diatoms are used as an indicator of ecosystem health in freshwaters because they are ubiquitous, directly affected by the changes in physico-chemical parameters and show a better relationship with environmental variables than other taxa e.g. invertebrates, giving a better overall picture of water quality.
Over the recent years, researchers have developed and standardised the tools for the metabarcoding and sequencing of diatoms, to complement the traditional assessment using microscopy, opening up a new avenue of biomonitoring for aquatic systems. Using benthic diatoms through a method of next-generation sequencing approach to river biomonitoring revealed a good potential in it. Many studies have shown that metabarcoding and HTS (high-throughput sequencing) can be utilized to estimate the quality status and diversity in freshwaters. As part of the Environment Agency, Kelly et al. has developed a DNA-based metabarcoding approach to assess diatom communities in rivers for the UK. Vasselon et al. compared morphological and HTS approaches for diatoms and found that HTS gave a reliable indication of quality status for most rivers in terms of Specific Polluosensitivity Index (SPI). Vasselon et al. also applied DNA metabarcoding of diatoms communities to the monitoring network of rivers on the tropical Island Mayotte (French DOM-TOM).
Rimet et al. also explored the possibility of using HTS for assessing diatom diversity and showed that diversity indices from both HTS and microscopic analysis were well correlated although not perfect.
DNA barcoding and metabarcoding can be used to establish molecular metrics and indices, which potentially provide conclusions broadly similar to those of the traditional approaches about the ecological and environmental status of aquatic ecosystems.
Forensics
Diatoms are used to as a diagnosis tool for drowning in forensic practices. The diatom test is based on the principle of diatom inhalation from water into the lungs and distribution and deposition around the body. DNA methods can be used to confirm if the cause of death was indeed drowning and locate the origin of drowning. Diatom DNA metabarcoding, provides the opportunity to quickly analyse the diatom community present within a body and locate the origin of drowning and investigate if a body may have been moved from one place to another.
Cryptic species and databasing
Diatom metabarcoding may help delimit cryptic species that are difficult to identify using microscopy and help complete reference databases by comparing morphological assemblages to metabarcoding data.
Other Microalgae
Chlorophytes possess an ancients and taxonomically very diverse lineage (Fang et al. 2014), including terrestrial plants too. Even though more than 14 000 species have been described based on structural and ultrastructural criteria (Hall et al. 2010) their morphological identification is often limited.
Several barcodes for chlorophytes have been proposed for DNA-based identification in order to bypass the problematics of the morphological one. Although the cytochrome oxidase I (COI, COX) coding gene (link) is a standard barcode for animals it proved to be unsatisfactory for chlorophytes because the gene contains several introns in this algae group (Turmel et al. 2002). Nuclear marker genes have been used for chlorophytes are SSU rDNA, LSU rDNA, rDNA ITS (Leliaert et al. 2014).
Macroalgae
Macroalgae—a morphological rather than taxonomic grouping—can be very challenging to identify because of their simple morphology, phenotypic plasticity and alternate lifecycle stages. Thus, algal systematics and identification have come to rely heavily on genetic/molecular tools such as DNA barcoding. The SSU rDNA gene is a common used barcode for phylogenetic studies on macroalgae. However, the SSU rDNA is a highly conserved region and typically lack resolution for species identification.
Over the past 2 decades certain standards for DNA barcoding with the aim of species identification have been developed for each of the main groups of macroalgae. The cytochrome c oxidase subunit I (COI) gene is commonly used as a barcode for red and brown algae, while tufA (plastid elongation factor), rbcL (rubisco large subunit) and ITS (internal transcribe spacer) are commonly used for green algae. These barcodes are typically 600-700 bp long.
The barcodes typically differ between the 3 main groups of macroalgae (red, green and brown) because their evolutionary heritage is very diverse. Macroalgae is a polyphyletic group, meaning that within the group they do not all share a recent common ancestor, making it challenging to find a gene that is conserved among all but variable enough for species identification.
Target regions
Adapted from
See also
Detailed information on DNA barcoding of different organisms can be found here:
Microbial DNA barcoding
DNA barcoding
Fish DNA barcoding
DNA barcoding in diet assessment
References
Authentication methods
Bioinformatics
Taxonomy (biology)
DNA barcoding | Algae DNA barcoding | Engineering,Biology | 3,076 |
234,854 | https://en.wikipedia.org/wiki/List%20of%20integrals%20of%20rational%20functions | The following is a list of integrals (antiderivative functions) of rational functions.
Any rational function can be integrated by partial fraction decomposition of the function into a sum of functions of the form:
which can then be integrated term by term.
For other types of functions, see lists of integrals.
Miscellaneous integrands
Integrands of the form xm(a x + b)n
Many of the following antiderivatives have a term of the form ln |ax + b|. Because this is undefined when x = −b / a, the most general form of the antiderivative replaces the constant of integration with a locally constant function. However, it is conventional to omit this from the notation. For example,
is usually abbreviated as
where C is to be understood as notation for a locally constant function of x. This convention will be adhered to in the following.
(Cavalieri's quadrature formula)
Integrands of the form xm / (a x2 + b x + c)n
For
Integrands of the form xm (a + b xn)p
The resulting integrands are of the same form as the original integrand, so these reduction formulas can be repeatedly applied to drive the exponents m and p toward 0.
These reduction formulas can be used for integrands having integer and/or fractional exponents.
Integrands of the form (A + B x) (a + b x)m (c + d x)n (e + f x)p
The resulting integrands are of the same form as the original integrand, so these reduction formulas can be repeatedly applied to drive the exponents m, n and p toward 0.
These reduction formulas can be used for integrands having integer and/or fractional exponents.
Special cases of these reductions formulas can be used for integrands of the form by setting B to 0.
Integrands of the form xm (A + B xn) (a + b xn)p (c + d xn)q
The resulting integrands are of the same form as the original integrand, so these reduction formulas can be repeatedly applied to drive the exponents m, p and q toward 0.
These reduction formulas can be used for integrands having integer and/or fractional exponents.
Special cases of these reductions formulas can be used for integrands of the form and by setting m and/or B to 0.
Integrands of the form (d + e x)m (a + b x + c x2)p when b2 − 4 a c = 0
The resulting integrands are of the same form as the original integrand, so these reduction formulas can be repeatedly applied to drive the exponents m and p toward 0.
These reduction formulas can be used for integrands having integer and/or fractional exponents.
Special cases of these reductions formulas can be used for integrands of the form when by setting m to 0.
Integrands of the form (d + e x)m (A + B x) (a + b x + c x2)p
The resulting integrands are of the same form as the original integrand, so these reduction formulas can be repeatedly applied to drive the exponents m and p toward 0.
These reduction formulas can be used for integrands having integer and/or fractional exponents.
Special cases of these reductions formulas can be used for integrands of the form and by setting m and/or B to 0.
Integrands of the form xm (a + b xn + c x2n)p when b2 − 4 a c = 0
The resulting integrands are of the same form as the original integrand, so these reduction formulas can be repeatedly applied to drive the exponents m and p toward 0.
These reduction formulas can be used for integrands having integer and/or fractional exponents.
Special cases of these reductions formulas can be used for integrands of the form when by setting m to 0.
Integrands of the form xm (A + B xn) (a + b xn + c x2n)p
The resulting integrands are of the same form as the original integrand, so these reduction formulas can be repeatedly applied to drive the exponents m and p toward 0.
These reduction formulas can be used for integrands having integer and/or fractional exponents.
Special cases of these reductions formulas can be used for integrands of the form and by setting m and/or B to 0.
References
Rational functions | List of integrals of rational functions | Mathematics | 1,011 |
62,558,712 | https://en.wikipedia.org/wiki/The%20Habitable%20Exoplanet%20Hunting%20Project | The Habitable Exoplanet Hunting Project is an international network of both professional and amateur astronomers. As of December 2019, the network comprises 32 observatories located worldwide, including universities such as the University of South Africa, the University of Saskatchewan in Canada, and the California Polytechnic State University.
The participants are searching for new potentially habitable exoplanets around non-flare G, K or M-type stars located within 100 light years. The initial list of targets consists of 10 stars that already have known transiting exoplanets outside the habitable zone.
The network is monitoring 24/7 each star at a time during several months. Despite G and K-type stars are the main targets of the project, the team is initially focusing on red dwarfs because it take less time to discard the existence of potentially habitable exoplanets around these type of stars.
Most of the observatories are able to detect transit depths as low as 0.1% and exoplanets with a radius of 0.7 Earth radii. To search for new exoplanets, the team is using two different methods: transit photometry and transit duration variation.
Overall, the project is a new approach to the quest for exoplanets in which a large network of astronomers located in the five continents have the time to continuously observe each star individually during long periods of time in the search for dips in brightness produced by transiting exoplanets.
As of December 2019, the network has already conducted observations on GJ 436 and GJ 1214, with a new campaign on GJ 3470 starting in January 2020. In July 2020, the group reported the discovery of GJ 3470 c.
See also
List of exoplanet search projects
References
Exoplanet search projects | The Habitable Exoplanet Hunting Project | Astronomy | 371 |
43,867,156 | https://en.wikipedia.org/wiki/Marasmius%20midnapurensis | Marasmius midnapurensis is a species of agaric fungus in the family Marasmiaceae that was first described scientifically in 2014. It is known only from its type locality, in the Midnapur district of West Bengal (India), where it grows on the dried leaves and wood of Acacia. Phylogenetic analysis of the internal transcribed spacer DNA suggests that the fungus is a species distinct from close relatives such as M. jasminodorus and M. aurantioferrugineus, and that it should be classified in Marasmius section Sicci.
See also
List of Marasmius species
References
midnapurensis
Fungi described in 2014
Fungi of Asia
Fungus species | Marasmius midnapurensis | Biology | 142 |
41,170,519 | https://en.wikipedia.org/wiki/Fuel%20cell%20forklift | A fuel cell forklift (also called a fuel cell lift truck) is a fuel cell powered industrial forklift used to lift and transport materials.
History
1960Allis-Chalmers builds the first fuel cell forklift.
Market
In 2013 there were over 4,000 fuel cell forklifts used in material handling in the United States. As of 2024, approximately 50,000 hydrogen forklifts are in operation worldwide (the bulk of which are in the U.S.), as compared with 1.2 million battery electric forklifts that were purchased in 2021.
Uses
PEM fuel-cell-powered forklifts provide benefits over petroleum-powered forklifts as they produce no local emissions. While LP Gas (propane) forklifts are more popular and often used indoors, they cannot accommodate certain food sector applications. Fuel cell power efficiency (40–50%) is about half that of lithium-ion batteries (80–90%), but they have a higher energy density which may allow forklifts to run longer. Fuel-cell-powered forklifts are often used in refrigerated warehouses as their performance is not as affected by temperature as some types of lithium batteries. Most fuel cells used for material handling purposes are powered by PEM fuel cells, although some DMFC forklifts are coming onto the market. In design the FC units are often made as drop-in replacements.
Research
2013Toyota Industries (Toyota Shokki) showcased a new fuel cell powered forklift, co-developed with Toyoda Gosei Co., Ltd.
2015HySA Systems (UWC) showcased a fuel cell powered forklift using a refueling station based on metal hydrides. The customer was Implats, a mining company in South Africa. This was the first project of this type on the African continent.
Standards
SAE J 2601/3 - SAE J 2601/3 - Fueling Protocols for Gaseous Hydrogen Powered Industrial Forklifts
References
Engineering vehicles
Electric vehicles
Trucks
Material-handling equipment
Fuel cell vehicles | Fuel cell forklift | Engineering | 418 |
37,840,569 | https://en.wikipedia.org/wiki/Electrochemical%20fatigue%20crack%20sensor | An Electrochemical Fatigue Crack Sensor (EFCS) is a type of low cost electrochemical nondestructive dynamic testing method used primarily in the aerospace and transportation infrastructure industries. The method is used to locate surface-breaking and slightly subsurface defects in all metallic materials. In bridge structures, EFCS is used at known fatigue susceptible areas, such as sharp-angled coped beams, stringer to beam attachments, and the toe of welds. This dynamic testing can be a form of short term or long-term monitoring, as long as the structure is undergoing dynamic cyclic loading.
History
In 1992, Dr. Campbell Laird and Dr. Yuanfeng Li invented the EFS™. The EFS™ relies on a patented electrical test method, which monitors the current flow at the surface of a metal while it is being mechanically flexed. The output current resembles a heart’s EKG pattern and can be interpreted to indicate the degree of fatigue as well as the presence of cracks in their earliest stages of development. The technology behind EFS was devised by researchers from the U.S. Air Force and the University of Pennsylvania for use in the aerospace industry. The original research was aimed at developing a technology for detecting problem cracks in airframes and engines. Since that time, additional research and development has resulted in the adaptation of the EFS system for steel bridge inspection.
Principles
The Electrochemical Fatigue Sensor (EFS) is a nondestructive crack dynamic inspection technology, similar in concept to a medical EKG, which is used to determine if actively growing fatigue cracks are present. An EFS sensor is first applied to the fatigue sensitive location on the bridge or metal structure, and then is injected with an electrolyte, at which point a small voltage is applied. The system subsequently monitors changes in the current response that results from the exposure of fresh steel during crack propagation. The EFS system consists of an electrolyte, a sensor array and a modified potentiostat call the potentiostat data link (PDL) for applying a constant polarizing voltage between the bridge and sensor, as well as data collection and analysis software.
The current response from the sensor array, which consists of a crack measurement sensor and a reference sensor, are collected, analyzed and compared with the system software. Data is presented in both the time domain and the frequency domain. An algorithm, specifically written for this system, automatically indicates the level of fatigue crack activity at the inspection location. EFS can detect cracks in the field as small as 0.01 inches in an actual structure (too small to be seen with the unaided eye).
Materials
The original research for the EFS was aimed at developing a technology for detecting problem cracks in airframes and engines.
Grade 5, also known as Ti6Al4V, Ti-6Al-4V, or Ti 6-4, is the most commonly used titanium alloy in the aerospace industry, such as internal combustion engine connecting rods. It features a chemical composition of 6% aluminium, 4% vanadium, 0.25% (maximum) iron, 0.2% (maximum) oxygen, and the remainder titanium. and the remaining portion titanium. Notably, Grade 5 is considerably stronger than commercially pure titanium, while sharing the same stiffness and thermal properties (excluding thermal conductivity, which is approximately 60% lower in Grade 5 Ti than in CP Ti). One of its notable advantages is its heat treatable. This grade exhibits an exceptional combination of strength, corrosion resistance, weldability, and fabricability. Typically, it finds application in uses up to temperatures of 400 degrees Celsius.
(Grade 5 has a density of approximately 4420 kg/m3, Young's modulus of 110 GPa, and tensile strength of 1000 MPa. By comparison, annealed type 316 stainless steel has a density of 8000 kg/m3, modulus of 193 GPa, and tensile strength of only 570 MPa and tempered 6061 aluminum alloy has a density of 2700 kg/m3, modulus of 69 GPa, and tensile strength of 310 MPa). EFS detects growing cracks in steel, aluminum, titanium alloys, and other metals.
Inspection steps
Below are the main steps of using Electrochemical Fatigue Sensors on a bridge:
1. Identification of Critical Areas:
To use the EFS on bridges, inspectors first identify the vulnerable parts of a bridge. These could be the areas most susceptible to wear and tear, such as sharp-angled coped beams, stringer to beam attachments, or the toe of welds. It could also be locations where bridge owners already suspect a crack.
2. Installation of Sensors:
The area to be monitored should be clean and free of any loose material. (The paint does not have to be totally removed as in other sensor installations.) The inspectors wire up the areas with sensors, which are similar to the peel-and-stick versions used for an EKG reading. The sensor array consists of a crack measurement sensor and a reference sensor.
3. Apply a Constant Current:
The sensors are injected with an electrolyte liquid which facilitates the applied constant electric current between the sensors and the bridge.
4. Monitoring:
The system monitors changes in the current response that results from the exposure of fresh steel during crack propagation.
5. Interpretation of Data:
The current response from the sensor array indicates quickly and clearly, whether a growing crack exists at the inspection location. And because the device is operated while the bridge is in use, it can determine how the cracks change as the structure flexes under stress. Data is presented in both the time domain and the frequency domain. An algorithm, specifically written for this system, automatically indicates the level of fatigue crack activity at the inspection location. The system can detect cracks in the field as small as 0.01 inches in an actual structure.
See also
Nondestructive testing
References
External links
Demonstration Of The Electrochemical Fatigue Sensor System At The Transportation Technology Center Facility
Inspection of Fatigue Cracks on a CN Bridge Using the Electrochemical Fatigue Sensor
Electrochemical Fatigue Sensor Demonstration on the Steel Bridge at Fast
Nondestructive testing
Sensors | Electrochemical fatigue crack sensor | Materials_science,Technology,Engineering | 1,253 |
51,559,227 | https://en.wikipedia.org/wiki/1%2C3-Diphenylurea | 1,3-Diphenylurea is a phenylurea-type compound with the formula (PhNH)2CO (Ph = C6H5). It is a colorless solid that is prepared by transamidation of urea with aniline.
DPU is a cytokinin, a type of plant hormone that induces flower development. The cytokinin effect of DPU is relatively low, but other more potent phenylurea-type cytokinins have been reported.
It was detected in coconut milk.
References
External links
Cytokinins
Ureas | 1,3-Diphenylurea | Chemistry | 129 |
11,798,335 | https://en.wikipedia.org/wiki/Zygosaccharomyces%20florentinus | Zygosaccharomyces florentinus is a plant pathogen.
See also
List of strawberry diseases
References
Fungal plant pathogens and diseases
Fungal strawberry diseases
Saccharomycetaceae
Fungi described in 1938
Fungus species | Zygosaccharomyces florentinus | Biology | 47 |
1,724,415 | https://en.wikipedia.org/wiki/Human%20reliability | In the field of human factors and ergonomics, human reliability (also known as human performance or HU) is the probability that a human performs a task to a sufficient standard. Reliability of humans can be affected by many factors such as age, physical health, mental state, attitude, emotions, personal propensity for certain mistakes, and cognitive biases.
Human reliability is important to the resilience of socio-technical systems, and has implications for fields like manufacturing, medicine and nuclear power. Attempts made to decrease human error and increase reliability in human interaction with technology include user-centered design and error-tolerant design.
Factors Affecting Human Performance
Human error, human performance, and human reliability are especially important to consider when work is performed in a complex and high-risk environment.
Strategies for dealing with performance-shaping factors such as psychological stress, cognitive load, fatigue include heuristics and biases such as confirmation bias, availability heuristic, and frequency bias.
Human reliability analysis
A variety of methods exist for human reliability analysis (HRA). Two general classes of methods are those based on probabilistic risk assessment (PRA) and those based on a cognitive theory of control.
PRA-based techniques
One method for analyzing human reliability is a straightforward extension of probabilistic risk assessment (PRA): in the same way that equipment can fail in a power plant, so can a human operator commit errors. In both cases, an analysis (functional decomposition for equipment and task analysis for humans) would articulate a level of detail for which failure or error probabilities can be assigned. This basic idea is behind the Technique for Human Error Rate Prediction (THERP). THERP is intended to generate human error probabilities that would be incorporated into a PRA. The Accident Sequence Evaluation Program (ASEP) human reliability procedure is a simplified form of THERP; an associated computational tool is Simplified Human Error Analysis Code (SHEAN). More recently, the US Nuclear Regulatory Commission has published the Standardized Plant Analysis Risk – Human Reliability Analysis (SPAR-H) method to take account of the potential for human error.
Cognitive control based techniques
Erik Hollnagel has developed this line of thought in his work on the Contextual Control Model (COCOM) and the Cognitive Reliability and Error Analysis Method (CREAM). COCOM models human performance as a set of control modes—strategic (based on long-term planning), tactical (based on procedures), opportunistic (based on present context), and scrambled (random) – and proposes a model of how transitions between these control modes occur. This model of control mode transition consists of a number of factors, including the human operator's estimate of the outcome of the action (success or failure), the time remaining to accomplish the action (adequate or inadequate), and the number of simultaneous goals of the human operator at that time. CREAM is a human reliability analysis method that is based on COCOM.
Related techniques
Related techniques in safety engineering and reliability engineering include failure mode and effects analysis, hazop, fault tree, and SAPHIRE (Systems Analysis Programs for Hands-on Integrated Reliability Evaluations).
Human Factors Analysis and Classification System (HFACS)
The Human Factors Analysis and Classification System (HFACS) was developed initially as a framework to understand the role of human error in aviation accidents. It is based on James Reason's Swiss cheese model of human error in complex systems. HFACS distinguishes between the "active failures" of unsafe acts, and "latent failures" of preconditions for unsafe acts, unsafe supervision, and organizational influences. These categories were developed empirically on the basis of many aviation accident reports.
"Unsafe acts" are performed by the human operator "on the front line" (e.g., the pilot, the air traffic controller, or the driver). Unsafe acts can be either errors (in perception, decision making or skill-based performance) or violations. Violations, or the deliberate disregard for rules and procedures, can be routine or exceptional. Routine violations occur habitually and are usually tolerated by the organization or authority. Exceptional violations are unusual and often extreme. For example, driving 60 mph in a 55-mph speed limit zone is a routine violation, while driving 130 mph in the same zone is exceptional.
There are two types of preconditions for unsafe acts: those that relate to the human operator's internal state and those that relate to the human operator's practices or ways of working. Adverse internal states include those related to physiology (e.g., illness) and mental state (e.g., mentally fatigued, distracted). A third aspect of 'internal state' is really a mismatch between the operator's ability and the task demands. Four types of unsafe supervision are: inadequate supervision; planned inappropriate operations; failure to correct a known problem; and supervisory violations.
Organizational influences include those related to resources management (e.g., inadequate human or financial resources), organizational climate (structures, policies, and culture), and organizational processes (such as procedures, schedules, oversight).
See also
(A Technique for Human Event Analysis)
, a technique used in the field of human reliability
(Tecnica Empirica Stima Errori Operatori)
Incident pit, conceptual model from diving for explaining incident development and recovery
Success Likelihood Index Method
Footnotes
References
Federal Aviation Administration. 2009 electronic code of regulations. Retrieved September 25, 2009, from https://web.archive.org/web/20120206214308/http://www.airweb.faa.gov/Regulatory_and_Guidance_library/rgMakeModel.nsf/0/5a9adccea6c0c4e286256d3900494a77/$FILE/H3WE.pdf
Further reading
CCPS, Guidelines for Preventing Human Error. This book explains about qualitative and quantitative methodology for predicting human error. Qualitative methodology called SPEAR: Systems for Predicting Human Error and Recovery, and quantitative methodology also includes THERP, etc.
External links
Standards and guidance documents
IEEE Standard 1082 (1997): IEEE Guide for Incorporating Human Action Reliability Analysis for Nuclear Power Generating Stations
DOE Standard DOE-HDBK-1028-2009 : Human Performance Improvement Handbook
Tools
EPRI HRA Calculator
Eurocontrol Human Error Tools
RiskSpectrum HRA software
Simplified Human Error Analysis Code
Research labs
Erik Hollnagel at the Crisis and Risk Research Centre at MINES ParisTech
Human Reliability Analysis at the US Sandia National Laboratories
Center for Human Reliability Studies at the US Oak Ridge National Laboratory
Flight Cognition Laboratory at NASA Ames Research Center
David Woods at the Cognitive Systems Engineering Laboratory at The Ohio State University
Sidney Dekker's Leonardo da Vinci Laboratory for Complexity and Systems Thinking, Lund University, Sweden
Media coverage
“How to Avoid Human Error in IT“
“Human Reliability. We break down just like machines“ Industrial Engineer – November 2004, 36(11): 66
Networking
High Reliability Management group at LinkedIn.com | Human reliability | Engineering | 1,454 |
7,736,821 | https://en.wikipedia.org/wiki/Phase%20factor | For any complex number written in polar form (such as ), the phase factor is the complex exponential (), where the variable is the phase of a wave or other periodic function. The phase factor is a unit complex number, i.e. a complex number of absolute value 1. It is commonly used in quantum mechanics and optics. It is a special case of phasors, which may have arbitrary magnitude (i.e. not necessarily on the unit circle in the complex plane).
Multiplying the equation of a plane wave by a phase factor shifts the phase of the wave by :
In quantum mechanics, a phase factor is a complex coefficient that multiplies a ket or bra . It does not, in itself, have any physical meaning, since the introduction of a phase factor does not change the expectation values of a Hermitian operator. That is, the values of and are the same. However, differences in phase factors between two interacting quantum states can sometimes be measurable (such as in the Berry phase) and this can have important consequences.
In optics, the phase factor is an important quantity in the treatment of interference.
See also
Berry phase
Bra-ket notation
Euler's formula
Phasor
Plane wave
The circle group U(1)
Notes
References
Information theory
Quantum information science
Notation | Phase factor | Mathematics,Technology,Engineering | 267 |
70,704,600 | https://en.wikipedia.org/wiki/Protein%20nanoparticles | Protein nanotechnology is a burgeoning field of research that integrates the diverse physicochemical properties of proteins with nanoscale technology. This field assimilated into pharmaceutical research to give rise to a new classification of nanoparticles termed protein (or protein-based) nanoparticles (PNPs). PNPs garnered significant interest due to their favorable pharmacokinetic properties such as high biocompatibility, biodegradability, and low toxicity Together, these characteristics have the potential to overcome the challenges encountered with synthetic NPs drug delivery strategies. These existing challenges including low bioavailability, a slow excretion rate, high toxicity, and a costly manufacturing process, will open the door to considerable therapeutic advancements within oncology, theranostics, and clinical translational research.
Continued advancement within this field is required for the clinical translation of PNPs. As of 2022, only one PNP formulation (Abraxane) and five VLPs (Gardasil, Ceravix, Mosquirix, Sci-B-Vac, Gardasil9) are approved by the FDA for clinical use. FDA approval of PNPs formulations is restrained by complications arising from in-vivo interactions between PNPs and the biological environment that jeopardize their safety or function. For example, PNPs may undergo protein conformation changes, form a protein corona, or induce inflammation and may risk patient well-being.
Synthesis methods
To capitalize on the favorable characteristics of PNPs, improvements within PNP synthesis methods are being widely explored. Advancements or the development of new synthesis methods are desirable as existing methods (sonochemistry, thermal decomposition, and colloidal/ hydrothermal/microemulsion methods) contribute to systemic toxicity and are limited to hydrophilic drugs. As a result, recent advancements seek to overcome these challenges and achieve commercial-size production.
In addition, newly developed PNP synthesis methods such as electrospray or desolvation provide a more sustainable approach as compared to traditional nanoparticle methods. Unlike synthetic nanoparticles, PNPs can be synthesized under mild conditions and without toxic chemicals or organic solvents. PNPs are also naturally sourced and readily degradable. Yet, despite these advantages and the addition of new synthesis methods, the methods remain relatively expensive and do not deliver full control of PNP size, greatly limiting their application in biomedicine
Types of protein
Numerous proteins are utilized in PNP synthesis. They are often sourced naturally from animal and plant sources. Accordingly, generally shared advantages of animal proteins include high biocompatibility, biodegradability, non-immunogenicity, drug loading efficiency, cell uptake, and easy and cost-effective production. Tables 2–4 below compile the common proteins used in PNP synthesis. The types of PNPs share similar physical properties such as high biocompatibility, non-immunogenicity, high drug efficiency, high biodegradability, and high cell uptake. Due to the abundance of proteins necessary for proper bodily function, the body has developed processes to update proteins into tissues and cells. PNPs take advantage of these natural processes to enhance their cellular uptake. This abundance and the natural sourcing subsequent purification of the proteins also reduce the immunogenic responses and produce low toxicity levels in the body. As the PNPs are degraded, the tissues assimilate the amino acids into energy or protein production.
Protein nanoparticle modifications
PNPs can be chemically modified to increase particle stability, reduce degradation, and enhance favorable characteristics. Crosslinking is a common modification that can utilize synthetic or natural cross-linkers. Natural cross-linkers are significantly less toxic than synthetic cross-linkers.
Driving factors in the modification of PNPs stem from their surface properties (surface charge, hydrophobicity, functional groups, etc.). Functional groups can bind to tissue-specific ligands for targeted drug delivery. Functional ligands may include protein receptors, antibodies, and smaller peptides. The purpose of ligand binding is to direct the PNP to the target cells, thereby reducing systemic toxicity, and improving the retention and excretion of the PNP within tissues. The optimal ligand for PNP modification is dependent on the target cell. Modification of a PNP surface with ligands can be achieved through chemical conjugation, though chemical dyes for imaging and peptides for immune activation can also be attached [11,33,34]. One example is the ligand anti-human epidermal growth factor receptor 2 which targets breast cancer cells. The following provides additional applications of ligand modifications and their therapeutic applications [12].
In addition to chemical conjugation, genetic modification can facilitate direct attachment of the modifying protein monomers with the PNP surface. This results in a co-assembly and a solution to existing challenges with direct attachments or large proteins. Attaching large proteins to PNPs interferes with the self-assembly process and induces steric interactions. Though, smaller protein attachments are generally tolerated by protein NPs. A significant limitation to direct attachment via genetic modification of protein monomers is that it cannot accommodate the attachment of multiple components. Enzymatic ligation helps overcome this limitation by providing a site-specific covalent link to the PNP surface following PNP assembly. This strategy can also provide greater control over the density and ratios of attached proteins.
The modification of VLPs is unique due to their nanocage architecture. PNPs with cage structures can fully encapsulate functional components in their interior, termed co-encapsulation. Drug encapsulation within VLP cages can occur through two processes. This first process occurs in-vitro and requires the disassembly of the cage and reassembling it with the presence of the drug components to be encapsulated [8]. Since loading efficiency is influenced through electrostatic interactions, the drug compounds cannot be fully encapsulated without interfering with the VLP cage self-assembly. Another process is the encapsulation of drug components in-vivo. This involves direct genetic attachment of the drug components to the interior of the VLP cage. This process guides drugs for encapsulation directly to the interior of the cage.
Therapeutic drug delivery applications
Due to PNPs’ breadth of favorable pharmacokinetic properties such as high biocompatibility, high biodegradability, high modifiability, low toxicity, high cell uptake, and a fast excretion rate, PNPs are prime candidates for anti-cancer therapy. Previous anticancer therapies relied on the enhanced permeability effect to passively accumulate within tumors. This resulted in greater toxicity due to higher concentrations required to achieve critical drug efficacy levels. Newer strategies allow PNPs to actively target the tumor microenvironment via the attachment of ligands and site-specific protein receptors. Active targeting decreases the total concentration of drugs required to deliver an effective dose, thereby reducing systemic side effects.
In addition to active tumor targeting, PNPs can also be engineered to respond to changing external environments such as pH, temperature, or enzyme concentration. The tumor microenvironment is slightly acidic, so PNPs can be engineered to only release their drug cargo under specific tumor physiological conditions.
Another application is photothermal or photodynamic therapy. PNPs selectively accumulate into the tumor microenvironment where they are subsequently irradiated using a 1064 nm wavelength laser. The light energy is transferred into heat energy, increasing the temperature of the tumor microenvironment to inhibit tumor growth. Ferritin is a favorable protein for this application due to its high thermal stability.
In-vivo imaging is another application of PNPs. PNPs can carry fluorescent dyes that selectively accumulate in the tumor microenvironment. This is important because a significant limitation of Green Fluorescent Protein, the standard protein for tumor imaging, is its insufficient deep tissue penetration. Due to their small size, PNPs can deliver fluorescent dyes deep into the tissue overcoming this challenge and providing more accurate tumor imaging. This strategy may also be applied to MRI imaging using PNPs carrying magnetic components to tumor microenvironments for subsequent scanning.
Other applications include vaccine development through VLPs carrying immunogenic components. Since VLPs are not carrying any attenuated genetic material, these vaccines pose a safer alternative, especially for the immunocompromised or elderly. PNPs may also treat neurological diseases as they can cross the blood-brain barrier [28]. Lastly. PNPs may find applications within ophthalmic drug delivery as PNPs have a significantly longer circulation time in the eye than eye drops.
Drug delivery challenges and regulations
Despite numerous pharmacokinetic advantages of PNPs, there remain several critical challenges to their clinical translation. Only two PNPs have been FDA-approved, despite over 50 PNP formulations to date (2022). The two FDA-approved drugs include Abraxane, an albumin nanoparticle carrying paclitaxel used for breast cancer, non-small cell lung cancer, and pancreatic cancer treatment. The second FDA-approved PNP is Ontak, a protein conjugate carrying L-2 and Diphtheria toxin used for cutaneous T-cell lymphoma. The two approved formulations are summarized in Table 5 below. The low approval rate of PNPs is due to limited existing control over drug encapsulation and the pharmacokinetic variability between PNP batches. Balancing both the repeatability of these two properties and their relative interactions is important because it ensures the predictability of their clinical outcomes, greater patient safety, and that protein loading does not interfere with the PNP's properties.
Another limitation surrounds the cost and ability of large-scale production. Many synthesis methods that can deliver greater homogeneity between produced nanoparticles are also more costly options or cannot achieve mass production. This limitation is compounded by the lower yields of PNP manufacturing. This limits the availability of PNPs to broad clinical adoption [20,29].
References
Protein complexes
Nanotechnology | Protein nanoparticles | Chemistry,Materials_science,Engineering | 2,124 |
19,398,243 | https://en.wikipedia.org/wiki/Hexatic%20phase | The hexatic phase is a state of matter that is between the solid and the isotropic liquid phases in two dimensional systems of particles. It is characterized by two order parameters: a short-range positional and a quasi-long-range orientational (sixfold) order. More generally, a hexatic is any phase that contains sixfold orientational order, in analogy with the nematic phase (with twofold orientational order).
It is a fluid phase, since the shear modulus and the Young's modulus vanish due to the dissociation of dislocations. It is an anisotropic phase, since there exists a director field with sixfold symmetry. The existence of the director field implies that an elastic modulus against drilling or torsion exists within the plane, that is usually called Frank's constant after Frederick C. Frank in analogy to liquid crystals. The ensemble becomes an isotropic liquid (and Frank's constant becomes zero) after the dissociation of disclinations at a higher temperature (or lower density). Therefore, the hexatic phase contains dislocations but no disclinations.
The KTHNY theory of two-step melting by i) destroying positional order and ii) destroying orientational order was developed by John Michael Kosterlitz, David J. Thouless, Bertrand Halperin, David Robert Nelson and A. P. Young in theoretical studies about topological defect unbinding two dimensions. In 2016, Kosterlitz and Thouless were awarded with the Nobel Prize in Physics (together with Duncan Haldane) for the idea that melting in 2D is mediated by topological defects. The hexatic phase was predicted by D. Nelson and B. Halperin; it does not have a strict analogue in three dimensions.
Order parameter
The hexatic phase can be described by two order parameters, where the translational order is short ranged (exponential decay) and the orientational order is quasi-long ranged (algebraic decay).
Translational order
If the position of atoms or particles is known, then the translational order can be determined with the translational correlation function as function of the distance between lattice site at place and the place , based on the two-dimensional density function in reciprocal space:
The vector points to a lattice site within the crystal, where the atom is allowed to fluctuate with an amplitude by thermal motion. is a reciprocal vector in Fourier space. The brackets denote a statistical average about all pairs of atoms with distance R.
The translational correlation function decays fast, i. e. exponential, in the hexatic phase. In a 2D crystal, the translational order is quasi-long range and the correlation function decays rather slow, i. e. algebraic; It is not perfect long range, as in three dimensions, since the displacements diverge logarithmically with systems size at temperatures above T=0 due to the Mermin-Wagner theorem.
A disadvantage of the translational correlation function is, that it is strictly spoken only well defined within the crystal. In the isotropic fluid, at the latest, disclinations are present and the reciprocal lattice vector is not defined any more.
Orientational order
The orientational order can be determined by the local director field of a particle at place , if the angles are taken, given by the bond to the nearest neighbours in sixfolded space, normalized with the number of nearest neighbours:
is a complex number of magnitude and the orientation of the six-folded director is given by the phase. In a hexagonal crystal, this is nothing else but the crystal-axes. The local director field disappears for a particle with five or seven nearest neighbours, as given by dislocations and disclinations , except a small contribution due to thermal motion. The orientational correlation function between two particles i and k at distance is now defined using the local director field:
Again, the brackets denote the statistical average about all pairs of particles with distance . All three thermodynamic phases can be identified with this orientational correlation function: it does not decay in the 2D crystal but takes a constant value (shown in blue in the figure). The stiffness against local torsion is arbitrarily large, Franks's constant is infinity. In the hexatic phase, the correlation decays with a power law (algebraic). This gives straight lines in a log-log-plot, shown in green in the Figure. In the isotropic phase, the correlations decay exponentially fast, this are the red curved lines in the log-log-plot (in a lin-log-plot, it would be straight lines). The discrete structure of the atoms or particles superimposes the correlation function, given by the minima at half integral distances . Particles which are poorly correlated in position, are also poorly correlated in their director.
See also
XY model
KTHNY theory
Kosterlitz–Thouless transition
External links
Nobel-talk 2016 from M. Kosterlitz
References
Theoretical physics | Hexatic phase | Physics | 1,036 |
72,573,008 | https://en.wikipedia.org/wiki/Marsh%20terrace | A marsh terrace is an artificially created berm that is built in a wetland to prevent erosion, reduce wave energy, and improve habitat for wildlife. Marsh terracing is most common throughout the upper Gulf Coast of the United States, where it is used to prevent coastal erosion, with 980 linear km (609 mi) having been built in Texas and Louisiana alone in the thirty years to 2020. The terraces catch sediment from rivers which is then colonized by plants to form marshland.
Construction and design
The design of marsh terraces depends on the local conditions such as wave strength and wind speed. There are several commonly used patterns, including chevrons (duck wings), straight lines, and square grids. Chevrons are the most effective pattern as wind can blow from any direction but there will still be calm water on at least one side of the chevron.
One thing that must be considered is the type of soil, as some are more vulnerable to erosion than others. Soils heavy with clay and silt are more resistant than soils primarily composed of organic matter.
Terraces are often built in shallow coastal ponds that may have been former marshland that has eroded away over time. Large berms, usually two to five meters in width, are built with material that is either dredged at the site or brought in as fill from inland. The berms themselves are often only a meter in height above sea level which allows it to be occasionally inundated with water and create the proper coastal plant community.
Marshland terraces are a relatively new construction, so far has only been extensively used in the Gulf Coast of the United States. They were first built at the Sabine National Wildlife Refuge in 1990. In 2021, a plan to create marsh terraces in Virginia's Back Bay National Wildlife Refuge has been approved. This will be the first project of its kind to be done in the Mid-Atlantic region.
Results
Being only constructed recently, there have not been a lot of published studies on the effects of marsh terracing. However, the existing results are promising. The terraces have a higher sediment accumulation rate compared to erosion, and are able to reduce wave strength by an average of 45%. The calmer waters allows sediment to settle which then promotes the growth of seagrasses which further hold down the sediment with their roots. Additionally, the terraces have been found to provide habitat for marsh wildlife such as seabirds and fish.
References
Ecological restoration
Environmental engineering
Hydrology
Land reclamation | Marsh terrace | Chemistry,Engineering,Environmental_science | 498 |
29,828,324 | https://en.wikipedia.org/wiki/Classical%20Cepheid%20variable | Classical Cepheids are a type of Cepheid variable star. They are young, population I variable stars that exhibit regular radial pulsations with periods of a few days to a few weeks and visual amplitudes ranging from a few tenths of a magnitude up to about 2 magnitudes. Classical Cepheids are also known as Population I Cepheids, Type I Cepheids, and Delta Cepheid variables.
There exists a well-defined relationship between a classical Cepheid variable's luminosity and pulsation period, securing Cepheids as viable standard candles for establishing the galactic and extragalactic distance scales. Hubble Space Telescope (HST) observations of classical Cepheid variables have enabled firmer constraints on Hubble's law, which describes the expansion rate of the observable Universe. Classical Cepheids have also been used to clarify many characteristics of our galaxy, such as the local spiral arm structure and the Sun's distance from the galactic plane.
Around 800 classical Cepheids are known in the Milky Way galaxy, out of an expected total of over 6,000. Several thousand more are known in the Magellanic Clouds, with more discovered in other galaxies; the Hubble Space Telescope has identified some in NGC 4603, which is 100 million light years distant.
Properties
Classical Cepheid variables are 4–20 times more massive than the Sun, and around 1,000 to 50,000 (over 200,000 for the unusual V810 Centauri) times more luminous. Spectroscopically they are bright giants or low luminosity supergiants of spectral class F6 – K2. The temperature and spectral type vary as they pulsate. Their radii are a few tens to a few hundred times that of the sun. More luminous Cepheids are cooler and larger and have longer periods. Along with the temperature changes their radii also change during each pulsation (e.g. by ~25% for the longer-period l Car), resulting in brightness variations up to two magnitudes. The brightness changes are more pronounced at shorter wavelengths.
Cepheid variables may pulsate in a fundamental mode, the first overtone, or rarely a mixed mode. Pulsations in an overtone higher than first are rare but interesting. The majority of classical Cepheids are thought to be fundamental mode pulsators, although it is not easy to distinguish the mode from the shape of the light curve. Stars pulsating in an overtone are more luminous and larger than a fundamental mode pulsator with the same period.
When an intermediate mass star (IMS) first evolves away from the main sequence, it crosses the instability strip very rapidly while the hydrogen shell is still burning. When the helium core ignites in an IMS, it may execute a blue loop and crosses the instability strip again, once while evolving to high temperatures and again evolving back towards the asymptotic giant branch. Stars more massive than about start core helium burning before reaching the red-giant branch and become red supergiants, but may still execute a blue loop through the instability strip. The duration and even existence of blue loops is very sensitive to the mass, metallicity, and helium abundance of the star. In some cases, stars may cross the instability strip for a fourth and fifth time when helium shell burning starts. The rate of change of the period of a Cepheid variable, along with chemical abundances detectable in the spectrum, can be used to deduce which crossing a particular star is making.
Classical Cepheid variables were B type main-sequence stars earlier than about B7, possibly late O stars, before they ran out of hydrogen in their cores. More massive and hotter stars develop into more luminous Cepheids with longer periods, although it is expected that young stars within our own galaxy, at near solar metallicity, will generally lose sufficient mass by the time they first reach the instability strip that they will have periods of 50 days or less. Above a certain mass, depending on metallicity, red supergiants will evolve back to blue supergiants rather than execute a blue loop, but they will do so as unstable yellow hypergiants rather than regularly pulsating Cepheid variables. Very massive stars never cool sufficiently to reach the instability strip and do not ever become Cepheids. At low metallicity, for example in the Magellanic Clouds, stars can retain more mass and become more luminous Cepheids with longer periods.
Light curves
A Cepheid light curve is typically asymmetric with a rapid rise to maximum light followed by a slower fall to minimum (e.g. Delta Cephei). This is due to the phase difference between the radius and temperature variations and is considered characteristic of a fundamental mode pulsator, the most common type of type I Cepheid. In some cases the smooth pseudo-sinusoidal light curve shows a "bump", a brief slowing of the decline or even a small rise in brightness, thought to be due to a resonance between the fundamental and second overtone. The bump is most commonly seen on the descending branch for stars with periods around 6 days (e.g. Eta Aquilae). As the period increases, the location of the bump moves closer to the maximum and may cause a double maximum, or become indistinguishable from the primary maximum, for stars having periods around 10 days (e.g. Zeta Geminorum). At longer periods the bump can be seen on the ascending branch of the light curve (e.g. X Cygni), but for period longer than 20 days the resonance disappears.
A minority of classical Cepheids show nearly symmetric sinusoidal light curves. These are referred to as s-Cepheids, usually have lower amplitudes, and commonly have short periods. The majority of these are thought to be first overtone (e.g. X Sagittarii), or higher, pulsators, although some unusual stars apparently pulsating in the fundamental mode also show this shape of light curve (e.g. S Vulpeculae). Stars pulsating in the first overtone are expected to only occur with short periods in our galaxy, although they may have somewhat longer periods at lower metallicity, for example in the Magellanic Clouds. Higher overtone pulsators and Cepheids pulsating in two overtones at the same time are also more common in the Magellanic Clouds, and they usually have low amplitude somewhat irregular light curves.
Discovery
On September 10, 1784 Edward Pigott detected the variability of Eta Aquilae, the first known representative of the class of classical Cepheid variables. However, the namesake for classical Cepheids is the star Delta Cephei, discovered to be variable by John Goodricke a month later. Delta Cephei is also of particular importance as a calibrator for the period-luminosity relation since its distance is among the most precisely established for a Cepheid, thanks in part to its membership in a star cluster<ref
name=dezeeuw1999></ref> and the availability of precise Hubble Space Telescope and Hipparcos parallaxes.
Period-luminosity relation
A classical Cepheid's luminosity is directly related to its period of variation. The longer the pulsation period, the more luminous the star. The period-luminosity relation for classical Cepheids was discovered in 1908 by Henrietta Swan Leavitt in an investigation of thousands of variable stars in the Magellanic Clouds. She published it in 1912 with further evidence. Once the period-luminosity relation is calibrated, the luminosity of a given Cepheid whose period is known can be established. Their distance is then found from their apparent brightness. The period-luminosity relation has been calibrated by many astronomers throughout the twentieth century, beginning with Hertzsprung. Calibrating the period-luminosity relation has been problematic; however, a firm Galactic calibration was established by Benedict et al. 2007 using precise HST parallaxes for 10 nearby classical Cepheids. Also, in 2008, ESO astronomers estimated with a precision within 1% the distance to the Cepheid RS Puppis, using light echos from a nebula in which it is embedded. However, that latter finding has been actively debated in the literature.
The following experimental correlations between a Population I Cepheid's period P and its mean absolute magnitude Mv was established from Hubble Space Telescope trigonometric parallaxes for 10 nearby Cepheids:
with P measured in days.
The following relations can also be used to calculate the distance d to classical Cepheids:
or
I and V represent near infrared and visual apparent mean magnitudes, respectively. The distance d is in parsecs.
Small amplitude Cepheids
Classical Cepheid variables with visual amplitudes below 0.5 magnitudes, almost symmetrical sinusoidal light curves, and short periods, have been defined as a separate group called small amplitude Cepheids. They receive the acronym DCEPS in the GCVS. Periods are generally less than 7 days, although the exact cutoff is still debated.
The term s-Cepheid is used for short period small amplitude Cepheids with sinusoidal light curves that are considered to be first overtone pulsators. They are found near the red edge of the instability strip. Some authors use s-Cepheid as a synonym for the small amplitude DCEPS stars, while others prefer to restrict it only to first overtone stars.
Small amplitude Cepheids (DCEPS) include Polaris and FF Aquilae, although both may be pulsating in the fundamental mode. Confirmed first overtone pulsators include BG Crucis and BP Circini.
Uncertainties in Cepheid determined distances
Chief among the uncertainties tied to the Cepheid distance scale are: the nature of the period-luminosity relation in various passbands, the impact of metallicity on both the zero-point and slope of those relations, and the effects of photometric contamination (blending) and a changing (typically unknown) extinction law on classical Cepheid distances. All these topics are actively debated in the literature.
These unresolved matters have resulted in cited values for the Hubble constant ranging between 60 km/s/Mpc and 80 km/s/Mpc. Resolving this discrepancy is one of the foremost problems in astronomy since the cosmological parameters of the Universe may be constrained by supplying a precise value of the Hubble constant.
Examples
Several classical Cepheids have variations that can be recorded with night-by-night, trained naked eye observation, including the prototype Delta Cephei in the far north, Zeta Geminorum and Eta Aquilae ideal for observation around the tropics (near the ecliptic and thus zodiac) and in the far south Beta Doradus. The closest class member is the North Star (Polaris) whose distance is debated and whose present variability is approximately 0.05 of a magnitude.
See also
RR Lyrae variable
Stellar pulsation
Type II Cepheid
References
External links
The Cepheid Distance Scale: A History, by Nick Allen
List of classical Cepheids on McMaster Cepheid Photometry and Radial Velocity Data Archive
American Association of Variable Star Observers
OGLE Atlas of Variable Star Light Curves – Classical Cepheids
Classical Cepheid variables
Astrometry
Standard candles | Classical Cepheid variable | Physics,Astronomy | 2,436 |
1,306,745 | https://en.wikipedia.org/wiki/Burn-in | Burn-in is the process by which components of a system are exercised before being placed in service (and often, before the system being completely assembled from those components). This testing process will force certain failures to occur under supervised conditions so an understanding of load capacity of the product can be established.
The intention is to detect those particular components that would fail as a result of the initial, high-failure rate portion of the bathtub curve of component reliability. If the burn-in period is made sufficiently long (and, perhaps, artificially stressful), the system can then be trusted to be mostly free of further early failures once the burn-in process is complete.
Theoretically, any weak components would fail during the "Burn In" time allowing those parts to be replaced. Replacing the weak components would prevent premature failure, infant mortality failure, or other latent defects.
When the equivalent lifetime of the stress is extended into the increasing part of the bathtub-like failure-rate curve, the effect of the burn-in is a reduction of product lifetime. In a mature production it is not easy to determine whether there is a decreasing failure rate. To determine the failure time distribution for a very low percentage of the production, one would have to destroy a very large number of devices. By stressing all devices for a certain burn-in time the devices with the highest failure rate fail first and can be taken out of the cohort. Thus by applying a burn-in, early in-use system failures can be avoided at the expense (tradeoff) of a reduced yield caused by the burn-in process.
When possible, it is better to eliminate the root cause of early failures than doing a burn-in. Because of this, a process that initially uses burn-in may eventually phase it out as the various root causes for failures are identified and eliminated.
For electronic components, burn-in is frequently conducted at elevated temperature and perhaps elevated voltage. This process may also be called heat soaking. The components may be under continuous test or simply tested at the end of the burn-in period.
There is another use of the term by some audiophiles, who leave new audio equipment turned on for multiple days or weeks, to get the components to achieve optimal performance. However, many debates have arisen about the benefits of this practice.
See also
Burn-in oven
Failure rate
Reliability theory
Survival analysis
Dielectric withstand test
Shakedown (testing)
References
Environmental testing
Hardware testing | Burn-in | Engineering | 500 |
7,505,780 | https://en.wikipedia.org/wiki/The%20Fountain%20in%20the%20Park | "The Fountain in the Park", also known as "While Strolling Through (or Thru') the Park One Day", is a song by Ed Haley, a member of the vaudeville act the Haley Brothers. Some authors believe the song was written by Robert A. Keiser, to whom Haley dedicated the song. The song was published in 1884 by Willis Woodward & Co. of New York, but dates from about 1880. It is best known for the lyric "While strolling through the park one day, in the merry merry month of May," and has been featured in numerous films, including Strike Up the Band (1940), in which it was sung by Judy Garland.
As early as 1938, Shep Fields and his Rippling Rhythm Orchestra recorded the song as a Swing Jazz fox trot entitled In the Merry Month of May for Bluebird Records (#B-7606, 1938) featuring the young concert accordionist John Serry Sr.
Bing Crosby included the song in a medley on his album 101 Gang Songs (1961)
Apollo 17
A few bars of "The Fountain in the Park" were sung on the Moon by NASA Astronauts Harrison Schmitt and Eugene Cernan on the Apollo 17 mission. Schmitt started by singing "I was strolling on the Moon one day..." when Cernan joined in. Cernan kept with the original "merry month of May", however, while Schmitt sang "December", which was the actual date at the time. After a brief debate, Schmitt resumed, singing "When much to my surprise, a pair of bonny eyes..." before humming the notes instead. Moments later, Capsule Communicator Robert A. Parker cut in from Houston, saying "sorry about that, guys, but today may be December."
Film
The Hollywood Revue of 1929 (1929)
Caught Plastered (1931)
The House on 56th Street (1933)
This Is My Affair (1937)
Idiot's Delight (1939)
The Ice Follies of 1939 (1939)
Strike Up the Band (1940)
The Strawberry Blonde (1941)
Unexpected Uncle (1941)
Yankee Doodle Dandy (1942)
Gentleman Jim (1942)
’’Strolling Thru the Park’’ (short with three couples dancing to the tune) (1943)
Heaven Can Wait (1943)
Show Business (1944)
Lake Placid Serenade (1944)
"Her Highness and the Bellboy" (1945)
I Wonder Who's Kissing Her Now (1947)
April Showers (1948)
Mr. Belvedere Rings the Bell (1951)
Million Dollar Mermaid (1952)
The FBI Story (1959)
Arabesque (1966)
Oh! What a Lovely War (1969)
TV and Animation
Mickey Mouse short The Nifty Nineties
Tom and Jerry short Baby Puss
Bugs Bunny shorts Elmer's Pet Rabbit, and Bushy Hare
Pepé Le Pew shorts Scentimental Romeo and Heaven Scent
I Love Lucy episode Pioneer Women.
The Simpsons episodes "Treehouse of Horror III" and "Brother's Little Helper"
Shining Time Station episode "Schemer's Robot"
The Magic School Bus episodes "Inside Ralphie" and "Goes to Seed"
The Real Ghostbusters episode "Very Beast Friends"
Alvin and the Chipmunks covered the song for their 1962 album The Chipmunk Songbook
Top Cat episode "The Missing Heir"
The Flintstones episode "The Hot Piano"
The Honeymooners episode "Life Upon the Wicked Stage"
Used as background music in the Animaniacs episode "Potty Emergency"
Sabrina: The Animated Series episode "Xabrina: Warrior Princess"
Used instrumentally as a leitmotif whenever the eccentric old gentleman would unexpectedly appear in the Merrie Melodies short The Dover Boys (1942)
Cassie in Dragon Tales from the episode "I Believe in Me" (from the first half of "I Believe in Me/Bye-Bye Baby Birdie") which was on Season 2 (though she calls it While Strolling Dragon Land One Day; which is sung to the tune of this song) (2001)
Kermit the Frog in Muppets Tonight (Episode 203: Heather Locklear)
References
External links
The Fountain in the Park sheet music from the Library of Congress.
RagPiano by Bill Edwards featuring background information on (and an audio recording of) The Fountain in the Park.
1884 songs
Songs about nostalgia
Music in space
Articles containing video clips | The Fountain in the Park | Astronomy | 908 |
49,115,677 | https://en.wikipedia.org/wiki/Peach%20%28social%20network%29 | Peach is a mobile application-based social network created by Dom Hofmann. Peach is available as an Android and iOS application. It was introduced at the January 2016 Consumer Electronics Show in Las Vegas.
Peach has been compared to Ello, Path, and App.net.
Peach has "magic words," which were compared to Slack's similar slash shortcuts. These allow the user to access commonly used functions such as typing the letter "g" to send a GIF or "c" to bring up a calendar, similar to a command line interface.
Peach eschews the traditional news feed, hashtagging, and tagging common to social networks. The editor-in-chief of The Next Web described Peach as a hybrid of Twitter and Slack, while noting that some users of the social network were creating fake celebrity accounts. Bloomberg Business noted that when it was introduced, "[e]verything about Peach... seemed hip, down to the URL", but that by the end of the month it appeared that "interest in Peach softened".
References
External links
American social networking websites
Internet properties established in 2016
Mobile social software
Image-sharing websites
Social information processing
IOS software
Android (operating system) software | Peach (social network) | Technology | 250 |
65,812,954 | https://en.wikipedia.org/wiki/Tobias%20Feilner | Tobias Christoph Feilner (19 May 1773, Weiden in der Oberpfalz - 7 April 1839, Berlin) was a German master potter. He also manufactured bricks, terracotta, molded stones and masonry heaters.
Biography
He was the third of ten children born to the master potter and city councilor, Philipp Heinrich Feilner. He learned the pottery trade from his father and left home in 1791, initially settling in Mannheim. There, he met his great uncle, , who had been Director of the Frankenthal Porcelain Factory since 1775. The knowledge thus gained enabled him to find work at the faience factories in
Alzey, Rheinhessen and Kurmainz. From 1792 to 1793, he worked for the master potter, Christian Leberecht Thomas, in Dresden.
With the assistance of Friedrich Abraham Wilhelm von Arnim (1767–1812), the Prussian Ambassador to Saxony, he was able to find a permanent position with Gottfried Höhler (1744-1812), who ran a furnace workshop in Berlin. He started there as a modeller, but was soon promoted to technical Foreman. In 1804, Feilner received a Royal Patent for an encaustic painting technique; used to create precise decorations on pottery and tiles. Höhler then made him a partner; leaving the business entirely in 1809. Following Höhler's death, the company became his.
In 1817, he expanded the company with a new factory building, and increased his workforce to 120 employees. He began producing terracotta in 1819. His products were used on the Friedrichswerder Church, the Old Palace, and the Church of Peace, Potsdam. Together with Karl Friedrich Schinkel, he developed a type of masonry heater that became standard in Germany by the middle of the 19th century. His heaters may still be seen at Schloss Tegel and Schloss Friedenstein, among many others. Some were sold in London, Rome and St. Petersburg. Until 1850, his company was the largest manufacturer of heaters in Germany. He was the teacher of another well known master potter, Ernst March. As a member of numerous trade and commercial organizations, he was also involved in civic affairs.
He married Charlotte Sophie Pausewang in 1800 and they had five children. Only two daughters survived to adulthood, however. One of them, Amalie, married the sculptor Ludwig Wilhelm Wichmann, who provided Feilner with numerous models for his terracotta work.
He died at the age of sixty-five and was interred at the . His grave has not been preserved. In 1848, on the initiative of King Frederick William IV, the street where his factory was located was renamed the "Feilnerstraße".
References
Further reading
Jan Mende: "Feilner nach Feilner. Die Tonwarenfabrik unter den Nachfolgern Tobias Feilners". In: Jahrbuch Stiftung Stadtmuseum Berlin. 9, Berlin 2003, pps.167–184.
Jan Mende: "Eisen und Terrakotta. Technische und künstlerische Parallelen". In: Charlotte Schreiter, Albrecht Pyritz (Eds.): Berliner Eisen. Die Königliche Eisengießerei Berlin. Zur Geschichte eines preußischen Unternehmens. Hannover 2007, , pps.171–186.
Jan Mende: Die Tonwarenfabrik Tobias Chr. Feilner in Berlin. Kunst und Industrie im Zeitalter Schinkels. Berlin/München 2013,
External links
1773 births
1839 deaths
German potters
Brick manufacturers
Terracotta
Manufacturer of architectural terracotta
People from Weiden in der Oberpfalz
18th-century German artisans | Tobias Feilner | Engineering | 779 |
10,138,549 | https://en.wikipedia.org/wiki/Morton%20number | In fluid dynamics, the Morton number (Mo) is a dimensionless number used together with the Eötvös number or Bond number to characterize the shape of bubbles or drops moving in a surrounding fluid or continuous phase, c.
It is named after Rose Morton, who described it with W. L. Haberman in 1953.
Definition
The Morton number is defined as
where g is the acceleration of gravity, is the viscosity of the surrounding fluid, the density of the surrounding fluid, the difference in density of the phases, and is the surface tension coefficient. For the case of a bubble with a negligible inner density the Morton number can be simplified to
Relation to other parameters
The Morton number can also be expressed by using a combination of the Weber number, Froude number and Reynolds number,
The Froude number in the above expression is defined as
where V is a reference velocity and d is the equivalent diameter of the drop or bubble.
References
Bubbles (physics)
Dimensionless numbers of fluid mechanics
Fluid dynamics | Morton number | Chemistry,Engineering | 206 |
11,127,872 | https://en.wikipedia.org/wiki/Hapalosphaeria%20deformans | Hapalosphaeria deformans is an ascomycete fungus. It is the causal organism of Stamen Blight of caneberry. It is a common disease in Pacific Northwest of North America (especially west of the Cascades, especially in Oregon), elsewhere in Canada, Denmark, Germany, Great Britain, Ireland, and Spain. It affects the commercial harvest of Oregon dewberries, and boysenberries and cascadeberries in British Columbia. It is not commercially significant in red raspberry in Scotland.
Hosts
Caneberries are hosts. Among cane species, known domesticated hosts are blackberry, boysenberry, cascadeberry, evergreen blackberry, loganberry, red raspberry, and youngberry, and nine wild Rubus including wild red raspberry.
See also
List of caneberries diseases
References
External links
Index Fungorum
USDA ARS Fungal Database
Enigmatic Ascomycota taxa
Fungal plant pathogens and diseases
Fungus species
Fungi described in 1907 | Hapalosphaeria deformans | Biology | 196 |
78,781,580 | https://en.wikipedia.org/wiki/HD%20147379 | HD 147379 (Gliese 617) is a wide visual binary between two red dwarfs in the deep northern constellation of Draco. The two stars are located approximately distant based on Gaia EDR3 parallax measurements, and approaching the Solar System at heliocentric radial velocities of −18.962 km/s and −18.36 km/s, respectively. The brighter primary star, HD 147379A, has an apparent magnitude of 8.9, too faint to be seen by the naked eye from Earth but visible using binoculars. The dimmer secondary, B, fluctuates in apparent magnitude between 10.69 and 10.74, making it observable via a telescope with an aperture of 35 mm or larger.
HD 147379A
HD 147379A (HIP 79755) is a red dwarf with a spectral type of M0.0V, about 58% the mass of the Sun, 57% the radius, and an age of . It emits just over a tenth of the luminosity of the Sun from its photosphere at an effective temperature of . It has a high metallicity of [Fe/H]=, meaning it has an iron content somewhere around 45% higher than the Sun. It is also enriched in cobalt, but is depleted in calcium and titanium. The star shows slight variations in the TiO spectral lines.
Planetary system
In 2018, two teams independently reported the discovery of an exoplanet orbiting HD 147379A, both via the radial-velocity method. This was the first exoplanet found by the CARMENES survey. The planet, commonly referred to as HD 147379 b, has a minimum mass of 21.6 ± 1.1 , slightly more massive than Neptune (17.147 ). It orbits its host star once every 86.58 days at about a third of the distance from Earth to the Sun, placing it within the conservative habitable zone of the star, where liquid water could exist.
One of the teams that discovered HD 147379 b proposed another candidate planet, this one with a minimum mass of 27 and a 500-day period, orbiting at a distance of about 1 AU. However, a 2023 follow-up study did not detect such a signal. Instead, they detected a signal with a 12.3-day period, but discarded it due to the high chance of it being a false positive. Nevertheless, it is highly likely that a second planet exists interior to b's orbit.
HD 147379B
HD 147379B (HIP 79762) is a gravitationally bound companion to HD 147379A at a separation of 64.4 arcseconds, which corresponds to a distance of 693.4 AU.
This is a red dwarf with a spectral type of M3V, about 45% the mass of the Sun and 46% the radius. It has a "partially convective" structure, meaning that the outer convection zone does not reach down to the core, as opposed to "fully convective" stars weighing less than 0.35 that are convective throughout. It too has a high metallicity of [M/H]=, translating to a roughly 60% excess in elements heavier than hydrogen and helium compared to the Sun. At an effective temperature of , it radiates just 2.6% the luminosity of the Sun from its photosphere. It rotates on its axis once every 40.4 days at a relatively slow projected equatorial velocity of 0.50 km/s.
It has a magnetic field that fluctuated in strength between 36-75 G between 2020-2022, approximately 100 times stronger than Earth's magnetic field (0.22-0.67 G) and similar to those of faster-rotating red dwarfs. The variations in strength are smaller than those seen in fully convective red dwarfs such as Gliese 1151.
In 1994, the star was reported to have a high likelihood (99%) of exhibiting long-term variability, albeit the author noted that this may be suspect. It was formally classified as a BY Draconis variable in 1997, receiving the variable-star designation EW Draconis.
References
Binary stars
Draco (constellation)
147379
079755
0617
M-type main-sequence stars
Planetary systems with one confirmed planet
BD+67 935
TIC objects
J16164280+6714196 | HD 147379 | Astronomy | 923 |
43,238,552 | https://en.wikipedia.org/wiki/Flamelet%20generated%20manifold | Flamelet-Generated Manifold (FGM) is a combustion chemistry reduction technique. The approach of FGM is based on the idea that the most important aspects of the internal structure of the flame front should be taken into account. In this view, a low-dimensional chemical manifold is created on the basis of one-dimensional flame structures, including nearly all of the transport and chemical phenomena as observed in three-dimensional flames. In addition, the progress of the flame is generally described by transport equations for a limited number of control variables.
See also
Combustion models for CFD
References
Further reading
Combustion | Flamelet generated manifold | Chemistry | 119 |
44,360,676 | https://en.wikipedia.org/wiki/Octotiamine | Octotiamine (INN, JAN; Gerostop, Neuvita, Neuvitan), also known as thioctothiamine, is an analogue of vitamin B1 which is used in Japan and Finland.
See also
Vitamin B1 analogue
References
Thiamine | Octotiamine | Chemistry | 58 |
31,646,712 | https://en.wikipedia.org/wiki/Tight%20oil | Tight oil (also known as shale oil, shale-hosted oil or light tight oil, abbreviated LTO) is light crude oil contained in unconventional petroleum-bearing formations of low permeability, often shale or tight sandstone. Economic production from tight oil formations requires the same hydraulic fracturing and often uses the same horizontal well technology used in the production of shale gas. While sometimes called "shale oil", tight oil should not be confused with oil shale (shale rich in kerogen) or shale oil (oil produced from oil shales). Therefore, the International Energy Agency recommends using the term "light tight oil" for oil produced from shales or other very low permeability formations, while the World Energy Resources 2013 report by the World Energy Council uses the terms "tight oil" and "shale-hosted oil".
In May 2013 the International Energy Agency in its Medium-Term Oil Market Report (MTOMR) said that the North American oil production surge led by unconventional oils—US light tight oil (LTO) and Canadian oil sands—had produced a global supply shock that would reshape the way oil is transported, stored, refined and marketed.
Inventory and examples
Tight oil formations include the Bakken Shale, the Niobrara Formation, Barnett Shale, and the Eagle Ford Shale in the United States, R'Mah Formation in Syria, Sargelu Formation in the northern Persian Gulf region, Athel Formation in Oman, Bazhenov Formation and Achimov Formation of West Siberia in Russia, Arckaringa Basin in Australia, Chicontepec Formation in Mexico, and the Vaca Muerta oil field in Argentina. In June 2013 the U.S. Energy Information Administration published a global inventory of estimated recoverable tight oil and tight gas resources in shale formations, "Technically Recoverable Shale Oil and Shale Gas Resources: An Assessment of 137 Shale Formations in 41 Countries Outside the United States." The inventory is incomplete due to exclusion of tight oil and gas from sources other than shale such as sandstone or carbonates, formations underlying the large oil fields located in the Middle East and the Caspian region, off shore formations, or about which there is little information. Amounts include only high quality prospects which are likely to be developed.
In 2012, at least 4,000 new producing shale oil (tight oil) wells were brought online in the United States. By comparison, the number of new producing oil and gas wells (both conventional and unconventional) completed in 2012 globally outside the United States and Canada is less than 4,000.
Characteristics
Tight oil shale formations are heterogeneous and vary widely over relatively short distances. Tight oil reservoirs subjected to fracking can be divided into four different groups. Type I has little matrix porosity and permeability – leading to fractures dominating both storage capacity and fluid flow pathways. Type II has low matrix porosity and permeability, but here the matrix provides storage capacity while fractures provide fluid-flow paths. Type III are microporous reservoirs with high matrix porosity but low matrix permeability, thus giving induced fractures dominance in fluid-flow paths. Type IV is macroporous reservoirs with high matrix porosity and permeability, thus the matrix provides both storage capacity and flow paths while fractures only enhance permeability.
Even in a single horizontal drill hole, the amount recovered may vary, as may recovery within a field or even between adjacent wells. This makes evaluation of plays and decisions regarding the profitability of wells on a particular lease difficult. Production of oil from tight formations requires at least 15 to 20 percent natural gas in the reservoir pore space to drive the oil toward the borehole; tight reservoirs which contain only oil cannot be economically produced. Formations which formed under marine conditions contain less clay and are more brittle, and thus more suitable for fracking than formations formed in fresh water which may contain more clay. Formations with more quartz and carbonate are more brittle.
The natural gas and other volatiles in LTO make it more hazardous to handle, store, and transport. This was an aggravating factor in the series of fatal explosions after the Lac-Mégantic derailment.
Exploitation
Prerequisites for exploitation include being able to obtain rights to drill, easier in the United States and Canada where private owners of subsurface rights are motivated to enter into leases; the availability of expertise and financing, easier in the United States and Canada where there are many independent operators and supporting contractors with critical expertise and suitable drilling rigs; infrastructure to gather and transport oil; and water resources for use in
hydraulic fracturing.
Analysts expect that $150 billion will be spent on further developing North American tight oil fields in 2015. The large increase in tight oil production is one of the reasons behind the price drop in late 2014.
Outside the United States and Canada, development of shale oil (tight oil) resources may be limited by the lack of available drilling rigs: 2/3 of the world's active drill rigs are in the US and Canada, and rigs elsewhere are less likely to be equipped for horizontal drilling. Drilling intensity may be another constraint, as tight-oil development requires far more completed wells than does conventional oil. Leonardo Maugeri considers this will be "an insurmountable environmental hurdle in Europe".
Detailed studies on production behaviour in prolific shale plays were light tight oil is produced have shown that the average monthly initial production of a tight oil well is around 500 barrels/day, which yields an estimated ultimate recovery in the range 150-290 thousand barrels. As a consequence, exploitation of tight oil tends to be drilling intensive with many new wells needed to ramp up and maintain production over time.
Size of tight oil resources
US EIA estimated technically recoverable tight oil in shale
Following are estimates of technically recoverable volumes of tight oil associated with shale formations, made by the US Energy Information Administration in 2013. Not all oil which is technically recoverable may be economically recoverable at current or anticipated prices.
Kingdom of Bahrain: 80 billion barrels
United States: 78 billion barrels
Russia: 75 billion barrels
China: 32 billion barrels
Argentina: 27 billion barrels
Libya: 26 billion barrels
Venezuela: 13 billion barrels
Mexico: 13 billion barrels
Pakistan: 9 billion barrels
Canada: 9 billion barrels
Indonesia: 8 billion barrels
World Total: 335 to 345 billion barrels
Other estimates
Australia: A private oil company announced in 2013 that it had discovered tight oil in shale of the Arckaringa Basin, estimated at 3.5 to 223 billion barrels.
Production
In September 2018, the U.S. Energy Information Administration projected October tight oil production in the U.S. at 7.6 million barrels per day.
The volume of oil production on tight oil formations in the US depends significantly on the dynamics of the WTI oil price. About six months after the price change, drilling activity changes, and with it the volume of production. These changes and their expectations are so significant that they themselves affect the price of oil and hence the volume of production in the future. These regularities are described in mathematical language by a differential extraction equation with a retarded argument.
Tight oil differs from conventional oil, as both investment and production dynamics of tight oil is significantly faster than conventional counterparts. This may reduce risks associated with locked-in capital and also contributed to a more flexible production that reduces oil price volatility. Unexpectedly, this faster dynamics can also entail lesser carbon lock-in effects and stranded asset risks with implications for climate policies.
See also
Shale gas
Shale oil extraction
Tight gas
Unconventional (oil & gas) reservoir
References
External links
Shale oil and tight oil
The Shale Oil Boom: a US Phenomenon by Leonardo Maugeri, Harvard University, Geopolitics of Energy Project, Belfer Center for Science and International Affairs, Discussion Paper 2013-05
Unconventional oil | Tight oil | Chemistry | 1,572 |
11,974,133 | https://en.wikipedia.org/wiki/CMU%20Pronouncing%20Dictionary | The CMU Pronouncing Dictionary (also known as CMUdict) is an open-source pronouncing dictionary originally created by the Speech Group at Carnegie Mellon University (CMU) for use in speech recognition research.
CMUdict provides a mapping orthographic/phonetic for English words in their North American pronunciations. It is commonly used to generate representations for speech recognition (ASR), e.g. the CMU Sphinx system, and speech synthesis (TTS), e.g. the Festival system. CMUdict can be used as a training corpus for building statistical grapheme-to-phoneme (g2p) models that will generate pronunciations for words not yet included in the dictionary.
The most recent release is 0.7b; it contains over 134,000 entries. An interactive lookup version is available.
Database format
The database is distributed as a plain text file with one entry to a line in the format "WORD <pronunciation>" with a two-space separator between the parts. If multiple pronunciations are available for a word, variants are identified using numbered versions (e.g. WORD(1)). The pronunciation is encoded using a modified form of the ARPABET system, with the addition of stress marks on vowels of levels 0, 1, and 2. A line-initial ;;; token indicates a comment. A derived format, directly suitable for speech recognition engines is also available as part of the distribution; this format collapses stress distinctions (typically not used in ASR).
The following is a table of phonemes used by CMU Pronouncing Dictionary.
History
Applications
The Unifon converter is based on the CMU Pronouncing Dictionary.
The Natural Language Toolkit contains an interface to the CMU Pronouncing Dictionary.
The Carnegie Mellon Logios tool incorporates the CMU Pronouncing Dictionary.
PronunDict, a pronunciation dictionary of American English, uses the CMU Pronouncing Dictionary as its data source. Pronunciation is transcribed in IPA symbols. This dictionary also supports searching by pronunciation.
Some singing voice synthesizer software like CeVIO Creative Studio and Synthesizer V uses modified version of CMU Pronouncing Dictionary for synthesizing English singing voices.
Transcriber, a tool for the full text phonetic transcription, uses the CMU Pronouncing Dictionary
15.ai, a real-time text-to-speech tool using artificial intelligence, uses the CMU Pronouncing Dictionary
See also
Moby Pronunciator, a similar project
References
External links
The current version of the dictionary is at SourceForge, although there is also a version maintained on GitHub.
Homepage – includes database search
RDF converted to Resource Description Framework by the open source Texai project.
English pronouncing dictionaries
Natural language processing
Public domain databases
Carnegie Mellon University
Software using the BSD license | CMU Pronouncing Dictionary | Technology | 597 |
53,297 | https://en.wikipedia.org/wiki/DESY | DESY, short for Deutsches Elektronen-Synchrotron (English: German Electron Synchrotron), is a national research centre for fundamental science located in Hamburg and Zeuthen near Berlin in Germany. It operates particle accelerators used to investigate the structure, dynamics and function of matter, and conducts a broad spectrum of interdisciplinary scientific research in four main areas: particle and high energy physics; photon science; astroparticle physics; and the development, construction and operation of particle accelerators. Its name refers to its first project, an electron synchrotron. DESY is publicly financed by the Federal Republic of Germany and the Federal States of Hamburg and Brandenburg and is a member of the Helmholtz Association.
Functions and mission
DESY's function is to conduct fundamental research for solely civil and peaceful purposes. It specialises in particle accelerator development, construction and operation, particle physics, astroparticle physics and photon science research to explore the fundamental relationships between the structure, dynamics and function of matter. In cooperation with its partner organisations, its photon science research spans surface physics, material science, chemistry, molecular biology, geophysics and medicine through the use of synchrotron radiation and free-electron lasers.
In addition to operating its own large accelerator facilities, DESY participates in many major international research projects, for example the European X-Ray Free-Electron Laser in Germany, the Large Hadron Collider in Switzerland, the Belle II experiment in Japan, the IceCube Neutrino Observatory at the South Pole and the worldwide Cherenkov Telescope Array.
Sites
DESY operates in two locations. The primary location is in the Bahrenfeld quarter of Hamburg. In 1992, DESY expanded to a second site in Zeuthen near Berlin.
Hamburg
The DESY Hamburg site is located in the quarter Bahrenfeld, in the west of the city in the district of Altona. Its main accelerators are located here.
Zeuthen
Following German reunification, DESY expanded to a second site in Zeuthen near Berlin. In 1939, the German Postal Ministry founded a nuclear physics laboratory there. After World War II, the laboratory was first named "Institute X", to become the Institute for High Energy Physics (), the high-energy physics laboratory of the German Democratic Republic belonging to the Academy of Sciences of the GDR. The institute was merged with DESY on 1 January 1992. It focuses on parallel computing for theoretical particle physics, the development and construction of electron sources for X-ray lasers as well as astroparticle physics with a focus on gamma-ray and neutrino astronomy.
Employees and training
DESY employs about 3,000 staff members from more than 60 nations. Most staff work at the Hamburg site, with about 270 at the Zeuthen site. These numbers include more than 130 trainees in various industrial-technical professions and about 500 PhD students and postdocs supervised by DESY. In addition, there are numerous master students from various universities.
Budget and financing
The research centre is a foundation under civil law financed by public funds. In 2020, DESY had an annual budget of about 232 million euros (according to the German federal budget plan, excluding expenditure for investments and special financing expenses). In addition, it had a third-party funding income of about 18 million euros. 90% of the annual budget is provided by the German Federal Ministry of Education and Research () and 10% respectively by the Free and Hanseatic City of Hamburg and the German federal state of Brandenburg.
Particle accelerators and other facilities
DESY's accelerators were not all built at once, but were rather added one by one to meet the growing demand of the scientists for higher and higher energies to gain more insight into particle structures. In the course of the construction of new accelerators, the older ones were converted to pre-accelerators or to sources for synchrotron radiation for laboratories with new research tasks.
DESY
The DESY synchrotron (short for "Deutsches Elektronen-Synchrotron") has been in operation since 1964. Its circumference is 300 m. It was used until 1978 for particle physics experiments and first measurements with synchrotron radiation. Since then, rebuilt and upgraded several times, it has served as a pre-accelerator and as a test beam facility delivering high-energy particle beams for testing detector systems.
DORIS
The DORIS storage ring (short for Double Ring Storage Facility) operated from 1974 to 2013. It had a circumference of 289 m. Until 1992, it collided electrons with positrons for particle physics experiments (including the ARGUS experiment). From 1980 on, the synchrotron radiation generated by DORIS was used for photon science experiments; from 1993 to 2012, the storage ring served exclusively as a synchrotron radiation source. The particle physics experiment OLYMPUS then ran in 2012 before DORIS was shut down at the beginning of 2013.
PETRA
The PETRA storage ring (short for Positron–Electron Tandem Ring Accelerator) has been in operation since 1978. It has a circumference of 2,304 m. Until 1986, electrons and positrons collided in PETRA for research in particle physics (experiments JADE, MARK-J, TASSO and PLUTO). From 1990 on, PETRA served as a pre-accelerator for the HERA storage ring, and from 1995 on also as a synchrotron radiation source with two test experimental stations. Since 2009, the facility has been delivering hard X-ray beams of very high brilliance to over 40 experimental stations under the name PETRA III.
HERA
The HERA storage ring (short for Hadron–Electron Ring Accelerator) operated from 1992 to 2007. It has a circumference of 6,336 m. It was DESY's largest ring accelerator and Germany's largest research instrument to date. Until 2007, HERA was the only storage ring facility in the world to enable collisions of electrons or positrons with protons for particle physics (experiments H1, ZEUS, HERMES and HERA-B) for studies of the inner structure of the proton.
FLASH
The free-electron laser (FEL) FLASH (short for Free-Electron Laser in Hamburg) has been in operation since 2000. It has a length of 315 m. It is based on a test facility for superconducting accelerator technology built in 1997 for the TESLA project and has served as a user facility for experiments with the generated FEL radiation since 2005. FLASH provides ultrashort light pulses in the extreme ultraviolet and soft X-ray range for seven experimental stations and is also used as a test facility for the development of accelerator and FEL technologies.
European XFEL accelerator
DESY operates the 1.7 km superconducting linear accelerator of the European XFEL X-ray free-electron laser, an international research facility that delivers ultrashort light pulses in the high-energy X-ray range.
PITZ
Since 2001, the DESY site in Zeuthen has been home to the photoinjector test facility PITZ, a linear accelerator used to study, optimise and prepare the electron sources for FLASH and (since 2015) for the European XFEL.
Other facilities
The building of the former DORIS storage ring now houses the SINBAD ("Short Innovative Bunches and Accelerators at DESY") accelerator complex with various infrastructures for accelerator R&D: the linear accelerator ARES for accelerator research with ultrashort electron pulses for medical purposes, the AXSIS facility for terahertz-driven acceleration to generate ultrashort X-ray pulses for materials science or medical imaging, and the high-power laser KALDERA for research into laser-driven plasma acceleration.
The LUX facility is also used for research into laser-driven plasma acceleration, the FLASHForward experiment at FLASH for electron-beam-driven plasma acceleration. The relativistic electron beam source REGAE generates ultrashort electron pulses for time-resolved diffraction experiments.
The tunnel of the former HERA storage ring now houses the ALPS II experiment, which uses converted superconducting dipole magnets of the HERA proton ring to study extremely light particles.
Computing
DESY provides extensive storage and computing capacity for research in all its divisions. As part of the Worldwide LHC Computing Grid (WLCG), DESY also operates a Tier-2 computer centre that offers computing and storage systems for the ATLAS, CMS and LHCb experiments at the Large Hadron Collider (LHC). In addition, the DESY grid infrastructure is used by other experiments such as Belle II or IceCube. DESY (Hamburg) also provides the Maxwell Cluster, a high-performance computing platform.
Research areas
Research at DESY is organised into four divisions: Accelerators, Photon Science, Particle Physics and Astroparticle Physics.
The Accelerator division develops fundamental technologies for the accelerator facilities that DESY and its partners use in their scientific mission. In addition to the operation and further development of existing facilities (PETRA IV and FLASH2020+ projects, expansion of the European XFEL), essential activities include research into new accelerator concepts, in particular plasma wakefield acceleration, and the improvement of superconducting radio frequency accelerator technology.
In the Photon Science division, photons are being used to study the structure, dynamics and function of matter. To this end, the division develops, builds and operates beamlines and experiments at the DESY light sources PETRA III and FLASH. Every year, more than 3,000 researchers – most of them from universities, but also from non-university research institutions and industry – from over 40 countries conduct experiments at the light sources and in the laboratories at DESY. The research spectrum ranges from basic research to applied research and industrial collaborations in physics, chemistry, biology, medicine, life sciences, earth sciences, materials research as well as the study of cultural heritage.
The Particle Physics division is involved in the large-scale experiments at the Large Hadron Collider (LHC) at CERN near Geneva. As part of the international collaborations that run the ATLAS and CMS experiments, DESY contributes to many developments at the LHC, from hardware design and data analysis to preparations for the planned upgrades. DESY also participates in the Belle II experiment at the electron–positron collider SuperKEKB at the research centre KEK in Tsukuba, Japan, as well as in developments for possible future electron–positron linear colliders. It is also active in theoretical particle physics.
The Astroparticle Physics division investigates high-energy processes in the universe. Detectors and telescopes are used to analyse neutrinos and gamma rays from space, which can provide information about cosmic phenomena: black holes, exploding stars and radiation bursts of extreme intensity. To this end, DESY is involved in the gamma telescopes MAGIC, H.E.S.S. and VERITAS as well as the Fermi Gamma-ray Space Telescope, and it contributes to the planned Cherenkov Telescope Array (CTA). It is the second largest partner in the IceCube observatory at the South Pole.
History
DESY was founded on 18 December 1959 in Hamburg. According to its statutes, DESY's mission is "the promotion of basic scientific research [...] in particular through the development, construction and operation of accelerators and their scientific use, in photon science and in the fields of particle and astroparticle physics, as well as through research and development work related thereto".
From 1959 to 2007, the DESY accelerators were primarily used for particle physics, initially with the eponymous DESY electron synchrotron (1964–present), followed by DORIS (Double Ring Storage Facility, 1974–1992), PETRA (Positron–Electron Tandem Ring Facility, 1978–present) and HERA (Hadron–Electron Ring Accelerator, 1992–2007). In 1987, the ARGUS experiment at DORIS was the first to observe a large mixing of B mesons and thus a process in which matter and antimatter behave differently. The most important discovery of the experiments TASSO, JADE, MARK-J and PLUTO at PETRA was the detection of the gluon, the messenger particle of the strong force, in 1979. From 1990, PETRA served as a pre-accelerator for the even larger storage ring HERA with its four experiments H1, ZEUS, HERMES and HERA-B. HERA was the only storage ring facility in the world in which protons collided with electrons or positrons. In these collisions, the point-like electron acted like a probe, scanning the inner structure of the proton and making it visible with high resolution. HERA's precise insights into the interior of the proton formed the basis for numerous other particle physics experiments, especially at the Large Hadron Collider (LHC) at the research centre CERN and for numerous developments in theoretical particle physics.
In parallel, as early as the 1960s, research groups from DESY, various universities and the Max Planck Society developed the technology for using the synchrotron radiation produced by the accelerators. To meet the rapidly growing national and European demand, DESY founded its own large laboratory: the Hamburg Synchrotron Radiation Laboratory HASYLAB, which opened in 1980. It provided measuring stations at DORIS, and it was here that the Israeli biochemist Ada Yonath (Nobel Prize in Chemistry 2009) conducted experiments from 1986 to 2004 that led to her deciphering the ribosome. From 1995, both synchrotron radiation and particle physics experiments were conducted at PETRA. In 2009, the PETRA facility was upgraded for exclusive use as a synchrotron radiation source for hard X-rays (PETRA III). Today, PETRA III serves over 40 experimental stations, and there are plans to expand it into the PETRA IV 3D X-ray microscope. With the shutdown of DORIS in early 2013, the name HASYLAB was abandoned, and the use of DESY's light sources has since been carried out in its Photon Science division.
In the early 1990s, DESY began to develop a new technology: radio frequency accelerator technology based on superconducting cavities made of niobium, which are cooled to approximately 2 K (−271 °C) with liquid helium. The first accelerator on this basis was a test facility for superconducting linear accelerators at DESY to test the principle of self-amplified spontaneous emission (SASE) of X-ray laser light. The SASE theory was developed and refined at DESY and at institutes in Russia, Italy and the USA from 1980 onwards. In 2000 to 2001, the test facility at DESY was the first free-electron laser in the world to produce light flashes in the vacuum ultraviolet and soft X-ray range. Today, the FLASH facility produces ultrashort light pulses in the soft X-ray range for seven experimental stations. Since 2020, it has been expanded to further optimise the properties of the radiation (FLASH2020+ project).
From 2009 to 2016, an international consortium led by DESY developed the European X-ray free-electron laser European XFEL. The international research facility, which involves 12 European shareholder countries, is operated by the non-profit company European XFEL GmbH. The core of the facility is a 1.7 km superconducting linear accelerator. With an electron energy of 17.5 GeV, it is the most powerful superconducting linear accelerator in the world to date. DESY operates the accelerator on behalf of European XFEL GmbH.
Since 2010, DESY has been developing plasma-based accelerator technology (both laser- and electron-beam-driven) as a possible alternative to conventional accelerator technologies, with the aim of enabling compact accelerators for photon science, particle physics as well as medical and industrial applications.
Chairpersons of the DESY Directorate
DESY is headed by a Directorate consisting of the directors of the four divisions (Accelerators, Photon Science, Particle Physics and Astroparticle Physics) and the administration as well as the delegate of the Directorate for innovation. Chairpersons of the Directorate so far have been:
1959 to 1970: Willibald Jentschke, Founding Director
1971 to 1972: Wolfgang Paul
1973 to 1980: Herwig Schopper
1981 to 1993: Volker Soergel
1993 to 1999: Bjørn H. Wiik
1999 to early 2009: Albrecht Wagner
since 2 March 2009: Helmut Dosch
Joint research centres
The DESY campus in Hamburg is the location of several national and international centres in which DESY participates. These are:
Center for Free-Electron Laser Science (CFEL): Investigation of ultrafast phenomena with free-electron lasers and optical lasers, studies of light–matter interaction under extreme conditions
Centre for Structural Systems Biology (CSSB): Structural systems biology to study infection processes at the molecular level of viruses, bacteria and parasites
Centre for X-ray and Nano Science (CXNS): Investigation of condensed matter with X-ray and complementary methods, high-resolution X-ray imaging, analysis of material processes
Knowledge and technology transfer
DESY aims to promote start-ups and bring know-how from fundamental research into application. It offers commercial companies support for industrial issues, e.g. through special industry access to photon sources and laboratories, develops ideas, applications and products based on fundamental research, and supports its employees in founding start-ups based on DESY technologies in the Hamburg and Brandenburg regions. DESY offers start-ups access to offices, laboratories and workshops in the DESY Innovation Village and the Start-up Labs Bahrenfeld, established together with the University of Hamburg and the Free and Hanseatic City of Hamburg.
References
External links
Buildings and structures in Altona, Hamburg
Education in Hamburg
Free-electron lasers
Organisations based in Hamburg
Particle physics facilities
Physics in Germany
Physics research institutes
Research institutes in Germany
Synchrotron radiation facilities | DESY | Materials_science | 3,671 |
5,715,706 | https://en.wikipedia.org/wiki/List%20of%20silicon%20producers | This is a list of silicon producers. The industry involves several very different stages of production. Production starts at silicon metal, which is the material used to gain high purity silicon. High purity silicon in different grades of purity is used for growing silicon ingots, which are sliced to wafers in a process called wafering. Compositionally pure polycrystalline silicon wafers are useful for photovoltaics. Dislocation-free and extremely flat single-crystal silicon wafers are required in the manufacture of computer chips.
Polysilicon producers
Polysilicon producers:
Elkem
JFE Steel
Nitol Solar (Russia), bankrupt since 2019
SunEdison
SolarWorld
High-purity silicon
Producers of high-purity silicon, an intermediate in the manufacture of polysilicon
Hemlock Semiconductor Corporation
Renewable Energy Corporation (REC)
SunEdison
Tokuyama Corporation
Wacker Chemie AG
Silicon wafer manufacturers
A partial list of major producers of wafers (made of high purity silicon, mono- or polycrystalline) includes:
GlobalWafers
Okmetic
Renewable Energy Corporation
Shin-Etsu Handotai
Siltronic
SUMCO
WaferPro
Pure Wafer
See also
List of photovoltaics companies
References
Silicon
Silicon | List of silicon producers | Chemistry | 252 |
5,878,203 | https://en.wikipedia.org/wiki/Schwartz%E2%80%93Bruhat%20function | In mathematics, a Schwartz–Bruhat function, named after Laurent Schwartz and François Bruhat, is a complex valued function on a locally compact abelian group, such as the adeles, that generalizes a Schwartz function on a real vector space. A tempered distribution is defined as a continuous linear functional on the space of Schwartz–Bruhat functions.
Definitions
On a real vector space , the Schwartz–Bruhat functions are just the usual Schwartz functions (all derivatives rapidly decreasing) and form the space .
On a torus, the Schwartz–Bruhat functions are the smooth functions.
On a sum of copies of the integers, the Schwartz–Bruhat functions are the rapidly decreasing functions.
On an elementary group (i.e., an abelian locally compact group that is a product of copies of the reals, the integers, the circle group, and finite groups), the Schwartz–Bruhat functions are the smooth functions all of whose derivatives are rapidly decreasing.
On a general locally compact abelian group , let be a compactly generated subgroup, and a compact subgroup of such that is elementary. Then the pullback of a Schwartz–Bruhat function on is a Schwartz–Bruhat function on , and all Schwartz–Bruhat functions on are obtained like this for suitable and . (The space of Schwartz–Bruhat functions on is endowed with the inductive limit topology.)
On a non-archimedean local field , a Schwartz–Bruhat function is a locally constant function of compact support.
In particular, on the ring of adeles over a global field , the Schwartz–Bruhat functions are finite linear combinations of the products over each place of , where each is a Schwartz–Bruhat function on a local field and is the characteristic function on the ring of integers for all but finitely many . (For the archimedean places of , the are just the usual Schwartz functions on , while for the non-archimedean places the are the Schwartz–Bruhat functions of non-archimedean local fields.)
The space of Schwartz–Bruhat functions on the adeles is defined to be the restricted tensor product of Schwartz–Bruhat spaces of local fields, where is a finite set of places of . The elements of this space are of the form , where for all and for all but finitely many . For each we can write , which is finite and thus is well defined.
Examples
Every Schwartz–Bruhat function can be written as , where each , , and . This can be seen by observing that being a local field implies that by definition has compact support, i.e., has a finite subcover. Since every open set in can be expressed as a disjoint union of open balls of the form (for some and ) we have
. The function must also be locally constant, so for some . (As for evaluated at zero, is always included as a term.)
On the rational adeles all functions in the Schwartz–Bruhat space are finite linear combinations of over all rational primes , where , , and for all but finitely many . The sets and are the field of p-adic numbers and ring of p-adic integers respectively.
Properties
The Fourier transform of a Schwartz–Bruhat function on a locally compact abelian group is a Schwartz–Bruhat function on the Pontryagin dual group. Consequently, the Fourier transform takes tempered distributions on such a group to tempered distributions on the dual group. Given the (additive) Haar measure on the Schwartz–Bruhat space is dense in the space
Applications
In algebraic number theory, the Schwartz–Bruhat functions on the adeles can be used to give an adelic version of the Poisson summation formula from analysis, i.e., for every one has , where . John Tate developed this formula in his doctoral thesis to prove a more general version of the functional equation for the Riemann zeta function. This involves giving the zeta function of a number field an integral representation in which the integral of a Schwartz–Bruhat function, chosen as a test function, is twisted by a certain character and is integrated over with respect to the multiplicative Haar measure of this group. This allows one to apply analytic methods to study zeta functions through these zeta integrals.
References
Number theory
Topological groups | Schwartz–Bruhat function | Mathematics | 903 |
37,657,137 | https://en.wikipedia.org/wiki/Faltings%27%20product%20theorem | In arithmetic geometry, Faltings' product theorem gives sufficient conditions for a subvariety of a product of projective spaces to be a product of varieties in the projective spaces. It was introduced by in his proof of Lang's conjecture that subvarieties of an abelian variety containing no translates of non-trivial abelian subvarieties have only finitely many rational points.
and gave explicit versions of Faltings' product theorem.
References
Diophantine approximation
Theorems in number theory | Faltings' product theorem | Mathematics | 104 |
4,211,471 | https://en.wikipedia.org/wiki/Rapid%20sand%20filter | The rapid sand filter or rapid gravity filter is a type of filter used in water purification and is commonly used in municipal drinking water facilities as part of a multiple-stage treatment system. These systems are complex and expensive to operate and maintain, and therefore less suitable for small communities and developing nations.
History
Rapid sand filters were first developed in the 1890s, and improved designs were developed by the 1920s. The first modern rapid sand filtration plant was designed and built by George W. Fuller in Little Falls, New Jersey. Rapid sand filters were widely used in large municipal water systems by the 1920s, because they required smaller land areas compared to slow sand filters.
Design and operation
Rapid sand filters are typically designed as part of multi-stage treatment systems used by large municipalities. These systems are complex and expensive to operate and maintain, and therefore less suitable for small communities and developing nations. The filtration system requires a relatively small land area in proportion to the population served, and the design is less sensitive to changes in raw water quality, e.g. turbidity, than slow sand filters.
Rapid sand filters use relatively coarse sand (0.5 to 1.0 mm) and other granular media, such as anthracite, in beds of 0.6 to 1.2 metre depth to remove particles and impurities that have been trapped in a floc through the use of flocculation chemicals—typically alum. Since media other than silica sand can be used in such filters, a more modern term is "rapid filtration" instead of "rapid sand filtration." The unfiltered water flows at about 5 m/h, through the filter medium under gravity or under pumped pressure and the floc material is trapped in the sand matrix.
Mixing, flocculation and sedimentation processes are typical treatment stages that precede filtration. Chemical additives, such as coagulants, are often used in conjunction with the filtration system.
The two types of rapid sand filter are the gravity type (e.g. Paterson's filter) and pressure type (e.g. Candy's filter).
A disinfection system (typically using chlorine or ozone) is commonly used following filtration. Rapid sand filtration has very little effect on taste and smell and dissolved impurities of drinking water, unless activated carbon is included in the filter medium.
Rapid sand filters must be cleaned frequently, often several times a day, by backwashing, which involves reversing the direction of the water and adding compressed air. During backwashing, the bed is fluidized and care must be taken not to wash away the media.
The backwash sequence would typically be:
Close inlet valve
Isolate controller
Allow water to drain down
Close outlet valve
Start air blower
Open air inlet valve
Air scour for 0-10 minutes
Stop air blowers
Close air valve
Wait 30 seconds
Start washwater pumps
Open upwash valve slowly
Open wash out valve
Wash water for 0-10 minutes
Close upwash valve
Raise washwater weir
Open surface flush inlet,
Surface flush for 0-5 minutes
Close washout valve
Lower washwater weir
Bring controller into service
Open inlet valve when filter is full
The byproduct of backwashing is sludge. Most treatment works use a sludge thickening process, except for plant which discharge untreated sludge to sewers if the composition is within the tolerable limits. The thickening process comprise batch settling tanks or continuous picket fence thickeners. Polyelectrolytes are added upstream to enhance settleability. Liquid from the process is routed to the inlet of the works. Thickening is followed by either lagooning, drying beds or filter pressing. Thickened sludge may be discharged to a sewer system, tankered away to landfill, or incinerator.
See also
Slow sand filter
Bank filtration
Biosand filter
Trickling filter
Automated pool cleaner
Notes
References
Water filters
Water technology | Rapid sand filter | Chemistry | 809 |
21,693,427 | https://en.wikipedia.org/wiki/Napkin%20ring%20problem | In geometry, the napkin-ring problem involves finding the volume of a "band" of specified height around a sphere, i.e. the part that remains after a hole in the shape of a circular cylinder is drilled through the center of the sphere. It is a counterintuitive fact that this volume does not depend on the original sphere's radius but only on the resulting band's height.
The problem is so called because after removing a cylinder from the sphere, the remaining band resembles the shape of a napkin ring.
Statement
Suppose that the axis of a right circular cylinder passes through the center of a sphere of radius and that represents the height (defined as the distance in a direction parallel to the axis) of the part of the cylinder that is inside the sphere. The "band" is the part of the sphere that is outside the cylinder. The volume of the band depends on but not on :
As the radius of the sphere shrinks, the diameter of the cylinder must also shrink in order that can remain the same. The band gets thicker, and this would increase its volume. But it also gets shorter in circumference, and this would decrease its volume. The two effects exactly cancel each other out. In the extreme case of the smallest possible sphere, the cylinder vanishes (its radius becomes zero) and the height equals the diameter of the sphere. In this case the volume of the band is the volume of the whole sphere, which matches the formula given above.
An early study of this problem was written by 17th-century Japanese mathematician Seki Kōwa. According to , Seki called this solid an arc-ring, or in Japanese kokan or kokwan.
Proof
Suppose the radius of the sphere is and the length of the cylinder (or the tunnel) is .
By the Pythagorean theorem, the radius of the cylinder is
and the radius of the horizontal cross-section of the sphere at height above the "equator" is
The cross-section of the band with the plane at height is the region inside the larger circle of radius given by (2) and outside the smaller circle of radius given by (1). The cross-section's area is therefore the area of the larger circle minus the area of the smaller circle:
The radius R does not appear in the last quantity. Therefore, the area of the horizontal cross-section at height does not depend on , as long as . The volume of the band is
and that does not depend on .
This is an application of Cavalieri's principle: volumes with equal-sized corresponding cross-sections are equal. Indeed, the area of the cross-section is the same as that of the corresponding cross-section of a sphere of radius , which has volume
See also
Visual calculus, an intuitive way to solve this type of problem, originally applied to finding the area of an annulus, given only its chord length
String girdling Earth, another problem where the radius of a sphere or circle is counter-intuitively irrelevant
References
Further reading
Problem 132 asks for the volume of a sphere with a cylindrical hole drilled through it, but does not note the invariance of the problem under changes of radius.
. Levi argues that the volume depends only on the height of the hole based on the fact that the ring can be swept out by a half-disk with the height as its diameter.
. Reprint of 1935 edition. A problem on page 101 describes the shape formed by a sphere with a cylinder removed as a "napkin ring" and asks for a proof that the volume is the same as that of a sphere with diameter equal to the length of the hole.
. Reprint of 1954 edition.
External links
Volume
Japanese mathematics
Recreational mathematics
Articles containing proofs
Mathematical problems | Napkin ring problem | Physics,Mathematics | 758 |
60,488,177 | https://en.wikipedia.org/wiki/Geminin%20coiled-coil%20domain-containing%20protein%201 | Geminin coiled-coil domain-containing protein 1 (GEMC1) is a Geminin family chromatin-binding protein encoded by the GMNC gene located on Chromosome 3 band 3q28. It is involved in the cell cycle, initiation of DNA replication, cilium assembly, and cell population proliferation. Reduced Generation of Multiple Motile Cilia (RGMC) is a rare ciliopathy characterized by hydrocephalus, the buildup of mucus in the airways, and reduced fertility that can be linked to defective multiple ciliated cell (MCC) differentiation, a process in which GEMC1, MCIDAS (another Geminin family protein), and CCNO are crucial.
Role in DNA replication
GEMC1 promotes the initiation of chromosomal DNA replication by mediating TOPBP1- and CDK2-dependent recruitment of CDC45L onto replication origins.
Role in Ciliogenesis
GEMC1 and MCIDAS transcriptionally activate E2F4/5-target genes during multiciliogenesis, including CCNO, which is necessary for the generation of multiple motile cilia.
Respiratory tract
The airways are lined by MCCs that generate the flow of mucus by beating in a coordinated manner. The downregulation of numerous genes by the Mir449/34 family of miRNAs followed by the activation of a transcriptional program by Geminin family members GEMC1 and MCIDAS is required for the generation of airway MCCs in fish, frogs and mammals.
Fertility
Male and female infertility has been observed in mice mutant for GEMC1, MCIDAS, or CCNO due to defective MCC differentiation. In females, MCC loss in the oviducts is the probable cause of infertility. The efferent duct epithelia of males contains MCCs that mobilize luminal fluids to prevent the agglutination of spermatozoa and promote fluid reabsorption. In mice mutant for these genes, degeneration of Sertoli cells, thinning of the seminiferous tubule epithelia, dilation of the rete testes and seminiferous tubules, sperm agglutinations in the efferent ducts, and lack of spermatozoa in the epididymis has been observed in conjunction with defects in MCC development.
References
Proteins | Geminin coiled-coil domain-containing protein 1 | Chemistry | 489 |
3,784,682 | https://en.wikipedia.org/wiki/National%20Information%20Assurance%20Partnership | The National Information Assurance Partnership (NIAP) is a United States government initiative to meet the security testing needs of both information technology consumers and producers that is operated by the National Security Agency (NSA), and was originally a joint effort between NSA and the National Institute of Standards and Technology (NIST).
Purpose
The long-term goal of NIAP is to help increase the level of trust consumers have in their information systems and networks through the use of cost-effective security testing, evaluation, and validation programs. In meeting this goal, NIAP seeks to:
Promote the development and use of evaluated IT products and systems
Champion the development and use of national and international standards for IT security
Common Criteria
Foster research and development in IT security requirements definition, test methods, tools, techniques, and assurance metrics
Support a framework for international recognition and acceptance of IT security testing and evaluation results
Facilitate the development and growth of a commercial security testing industry within the U.S.
Services
Common Criteria Evaluation and Validation Scheme (CCEVS)
Product / System Configuration Guidance
Product and Protection Profile Evaluation
Consistency Instruction Manuals
NIAP Validation Body
The principal objective of the NIAP Validation Body is to ensure the provision of competent IT security evaluation and validation services for both government and industry. The Validation Body has the ultimate responsibility for the operation of the CCEVS in accordance with its policies and procedures, and where appropriate: interpret and amend those policies and procedures. The NSA is responsible for providing sufficient resources to the Validation Body so that it may carry out its responsibilities.
The Validation Body is led by a Director and Deputy Director selected by NSA management. The Director of the Validation Body reports to the NIAP Director for administrative and budgetary matters and to NSA certificate-issuing authorities for CCEVS related operational matters. In general, the Director and Deputy Director serve a two-year term of service. This term of service may be extended at the discretion of NSA management. There are also a significant number of technical and administrative support personnel required to provide a full range of validation services for the sponsors of evaluations and the Common Criteria Testing Laboratories (CCTL). These personnel include validators, technical experts in various technology cells, and senior members of the technical staff and the IT security community on the oversight board.
The Validation Body ensures that appropriate mechanisms are in place to protect the interests of all parties within the CCEVS participating in the process of IT security evaluation. Any dispute brought forth by a participating party, (i.e., sponsor of an evaluation, product or Protection Profile developer or CCTL), concerning the operation of the CCEVS or any of its associated activities shall be referred to the Validation Body for resolution. In disputes involving the Validation Body, NSA management will attempt to resolve the dispute through procedures agreed upon by the two organizations.
External links
NIAP official site
NIAP Consistency Instruction Manuals
Crime prevention
Data security
National Security Agency
Security | National Information Assurance Partnership | Engineering | 584 |
72,882,323 | https://en.wikipedia.org/wiki/Journal%20of%20Hazardous%20Materials | The Journal of Hazardous Materials is a peer-reviewed, scientific journal that covers the study of hazardous materials and their impact on the environment. The journal is published by Elsevier and was established in 1975. Since 2022, the editor-in-chief is Zhen He (Washington University in St. Louis). The journal publishes original research articles, review articles, and short communications.
Abstracting and indexing
The journal is abstracted and indexed in:
According to the Journal Citation Reports, the journal has a 2021 impact factor of 14.224.
References
External links
Materials science journals
English-language journals
Elsevier academic journals
Academic journals established in 1975
Journals published between 13 and 25 times per year | Journal of Hazardous Materials | Materials_science,Engineering | 140 |
13,161,364 | https://en.wikipedia.org/wiki/Thiocyanogen | Thiocyanogen, (SCN)2, is a pseudohalogen derived from the pseudohalide thiocyanate, [SCN]−, with behavior intermediate between dibromine and diiodine. This hexatomic compound exhibits C2 point group symmetry and has the connectivity NCS-SCN.
In the lungs, lactoperoxidase may oxidize thiocyanate to thiocyanogen or hypothiocyanite.
History
Berzelius first proposed that thiocyanogen ought exist as part of his radical theory, but the compound's isolation proved problematic. Liebig pursued a wide variety of synthetic routes for the better part of a century, but, even with Wöhler's assistance, only succeeded in producing a complex mixture with the proportions of thiocyanic acid. In 1861, Linnemann generated appreciable quantities of thiocyanogen from a silver thiocyanate suspension in diethyl ether and excess iodine, but misidentified the minor product as sulfur iodide cyanide (ISCN). Indeed, that reaction suffers from competing equilibria attributed to the weak oxidizing power of iodine; the major product is sulfur dicyanide. The following year, Schneider produced thiocyangen from silver thiocyanate and disulfur dichloride, but the product disproportionated to sulfur and trisulfur dicyanides.
The subject then lay fallow until the 1910s, when Niels Bjerrum began investigating gold thiocyanate complexes. Some eliminated reductively and reversibly, whereas others appeared to irreversibly generate cyanide and sulfate salt solutions. Understanding the process required reanalyzing the decomposition of thiocyanogen using the then-new techniques of physical chemistry. Bjerrum's work revealed that water catalyzed thiocyanogen's decomposition via hypothiocyanous acid. Moreover, the oxidation potential of thiocyanogen appeared to be 0.769 V, slightly greater than iodine but less than bromine. In 1919, Söderbäck successfully isolated stable thiocyanogen from oxidation of oxidation of plumbous thiocyanate with bromine.
Preparation
Modern syntheses typically differ little from Söderbäck's process. Thiocyanogen synthesis begins when aqueous solutions of lead(II) nitrate and sodium thiocyanate, combined, precipitate plumbous thiocyanate. Treating an anhydrous Pb(SCN)2 suspension in glacial acetic acid with bromine then affords a 0.1M solution of thiocyanogen that is stable for days. Alternatively, a solution of bromine in methylene chloride is added to a suspension of Pb(SCN)2 in methylene chloride at 0 °C.
Pb(SCN)2 + Br2 → (SCN)2 + PbBr2
In either case, the oxidation is exothermic.
An alternative technique is the thermal decomposition of cupric thiocyanate at 35–80 °C:
2Cu(SCN)2 → 2 CuSCN + (SCN)2
Reactions
In general, thiocyanogen is stored in solution, as the pure compound explodes above 20 °C to a red-orange polymer. However, the sulfur atoms disproportionate in water:
3(SCN)2 + 4H2O → H2SO4 + HCN + 5HSCN
Thiocyanogen is a weak electrophile, attacking only highly activated (phenolic or anilinic) or polycyclic arenes. It attacks carbonyls at the α position. Heteratoms are attacked more easily, and the compound thiocyanates sulfur, nitrogen, and various poor metals. Thiocyanogen solutions in nonpolar solvents react almost completely with chlorine to give chlorine thiocyanate; but the corresponding bromine thiocyanate is unstable above −50 °C, forming polymeric thiocyanogen and bromine.
The compound adds trans to alkenes to give 1,2-bis(thiocyanato) compounds; the intermediate thiiranium ion can be trapped with many nucleophiles. Radical polymerization is the most likely side-reaction, and yields improve when cold and dark. However, the addition reaction is slow, and light may be necessary to accelerate the process. Titanacyclopentadienes give (Z,Z)-1,4-bis(thiocyanato)-1,3-butadienes, which in turn can be converted to 1,2-dithiins. Thiocyanogen only adds once to alkynes; the resulting dithioacyloin dicyanate is not particularly olefinic.
Selenocyanogen, (SeCN)2, prepared from reaction of silver selenocyanate with iodine in tetrahydrofuran at 0 °C, reacts in a similar manner to thiocyanogen.
Applications
Thiocyanogen has been used to estimate the degree of unsaturation in fatty acids, similar to the iodine value.
References
Inorganic carbon compounds
Inorganic sulfur compounds
Inorganic nitrogen compounds
Thiocyanates
Pseudohalogens | Thiocyanogen | Chemistry | 1,143 |
42,610,193 | https://en.wikipedia.org/wiki/Permeability%20of%20soils | A number of factors affect the permeability of soils, from particle size, impurities in the water, void ratio, the degree of saturation, and adsorbed water, to entrapped air and organic material.
Background
Soil aeration maintains oxygen levels in the plants' root zone, needed for microbial and root respiration, and important to plant growth. Additionally, oxygen levels regulate soil temperatures and play a role in some chemical processes that support the oxidation of elements like Mn2+ and Fe2+ that can be toxic.
Determination of the permeability coefficient
Laboratory experiments:
Constant Head Permeability Test,
Low-level permeability test,
Horizontal permeability test.
Field experiments:
Free aquifer,
Pressured aquifer.
Composition
There is great variability in the composition of soil air as plants consume gases and microbial processes release others. Soil air is relatively moist compared with atmospheric air, and CO2 concentrations tend to be higher, while O2 is usually quite a bit lower. O2 levels are higher in well-aerated soils, which also have higher levels of CH4 and N2O than atmospheric air.
Particle size
It was studied by Allen Hazen that the coefficient of permeability (k) of a soil is directly proportional to the square of the particle size (D). Thus permeability of coarse grained soil is very large as compared to that of fine grained soil. The permeability of coarse sand may be more than one million times as much that of clay.
Impurities in soil
The presence of fine particulate impurities in a soil can decrease its permeability by progressive clogging of its porosity.
Void ratio (e)
The coefficient of permeability varies with the void ratio as e/sup>/(1+e). For a given soil, the greater the void ratio, the higher the value of the coefficient of permeability. Here 'e' is the void ratio.
Based on other concepts it has been established that the permeability of a soil varies as e2 or e3/(1+e). Whatever may be the exact relationship, all soils have e versus log k plot as a straight line.
Degree of saturation
If the soil is not fully saturated, it contains air pockets. The permeability is reduced due to the presence of air which causes a blockage to the passage of water. Consequently, the permeability of a partially saturated soil is considerably smaller than that of fully saturated soil. In fact, Darcy's Law is not strictly applicable to such soils.
Absorbed water
Fine grained soils have a layer of adsorbed water strongly attached to their surface. This adsorbed layer is not free to move under gravity. It causes an obstruction to the flow of water in the pores and hence reduces the permeability of soils. According to Casagrande, it may be taken as the void ratio occupied by absorbed water and the permeability may be roughly assumed to be proportional to the square of the net voids ratio of (e - 0.1)
Entrapped air and organic matter
Air entrapped in the soil and organic matter block the passage of water through soil, hence permeability considerably decreases. In permeability tests, the sample of soil used should be fully saturated to avoid errors.
See also
Darcy's Law
Hydraulic conductivity
Permeability (Earth sciences)
Soil
Soil mechanics
References
Soil science
Pedology
Soil mechanics | Permeability of soils | Physics | 711 |
26,043,539 | https://en.wikipedia.org/wiki/Copper%20metallurgy%20in%20Africa | Copper metallurgy in Africa encompasses the study of copper production across the continent and an understanding of how it influenced aspects of African archaeology.
Origins
Scholars previously believed that sub-Saharan Africans either did not have a period of using copper until the nineteenth century (going from the Stone Age directly into the Iron Age), or that they started smelting iron and copper at the same time. Copper smelting is thought to have been practiced in Nubia, during the early Old Kingdom c. 2686–2181 BC.
The principal evidence for this claim is an Egyptian outpost established in Buhen (near today's Sudanese-Egyptian border) around 2600 BC to smelt copper ores from Nubia. Alongside this, a crucible furnace dating to 2300–1900 BC for bronze casting has been found at the temple precinct at Kerma (in present-day northern Sudan), however the source of the tin remains unknown. Over the next millennium Nubians developed great skill in working copper and other known metals.
Discoveries in the Agadez Region of Niger evidence signs of copper metallurgy as early as 2000 BC. This date pre-dates the use of iron by a thousand years. Copper metallurgy seems to have been an indigenous invention in this area, because there is no clear evidence of influences from Northern Africa, and the Saharan wet phase was coming to an end, hindering human interactions across the Saharan region. It appeared to not be fully developed copper metallurgy, which suggests it was not from external origins. The people used native copper at first, and experimented with different furnace styles in order to smelt the ore between 2500 and 1500 BC.
Copper metallurgy has been recorded at Akjoujt in western Mauritania. The Akjoujt site is later than Agadez, dating back to around 850 BC. There is evidence of mining between 850 and 300 BC. Radiocarbon dates from the Grotte aux Chauves-souris mine shows that the extraction and smelting of malachite goes back to the early fifth century BC. A number of copper artifacts—including arrow points, spearheads, chisels, awls and plano-convex axes as well as bracelets, bead and earrings—were found at Neolithic sites in the region.
Collecting dates from Tropical Africa has been extremely difficult. No dates are available for the copper mine in pre-colonial Nigeria, and the earliest dates available south of the equator are around 345 AD at Naviundu springs near Lubumbashi in the Democratic Republic of Congo (DRC). Kansanshi mine in Zambia and Kipushi mine in the DRC date to between the fifth and twelfth centuries. Sites further south have produced later dates, for example the Thakadu mines in Botswana date to between 1480 and 1680; other major mines in Botswana, Namibia, and South Africa remain undated.
Ore sources
The mineralization of copper is restricted to a few areas in western, central and southern Africa, and some have the richest deposits of copper in the world. In the west, copper has only been found in the arid regions of the Sahel and southern Sahara. The main sources of copper are:
Akjoujt in Mauritania
Nioro du Sahel to Sirakoro in Northern Mali
The Aïr Massif near Azelik and Agadez in Niger
There are not any known mines in tropical West Africa, however copper and lead workings have been in the Benue Trough in southeastern Nigeria. With the exception of a few areas near Kilembe in Uganda and Rwanda, there are no sources of copper in East Africa. The largest concentration of copper found in Africa is the Lufilian Arc. It is an eight hundred kilometer crescent shaped belt, which extends from the Copperbelt in Zambia to the southern Shaba Province in Congo.
Mining and processing
Early African miners used copper oxides and carbonates rather than sulfides, because they were able to reduce oxides and carbonates to copper metal, but not sulfides. Sulfides were more complex to reduce to metal and required multiple stages. Complex deep-mining methods and special tools were not needed, because oxides were structurally weakened by decomposition processes and contained the most desirable ores, and although the techniques used seemed to be simple, Africans were very successful in extracting large quantities of high-grade ore.
The copper mines themselves were most frequently open stopes or open stopes with shafts. Shafts were rare in African copper mining. There are several ethnographic accounts of African copper mining techniques, and they all seem to be on the same technological level. Any variation depended upon different geological circumstances and capabilities of the miners.
There are more variations of copper smelting than there are of mining, and most of the observations and photos that were taken are in major copper producing areas. There is a lack of evidence of smelting in West Africa; however casting continued to be present and is well documented. The most common ore in Africa is malachite and it was used mainly with hardwood charcoal the smelting process.
Copper throughout Africa
West Africa
In sub-Saharan West Africa, there were only two known source of copper that were commercially viable: Dkra near Nioro, Mali and Takedda in Azelik, Niger. Akjoujt was a significant source of copper, but due to the lack of timber it lost its significance in early historic times. The sources for West Africa's copper came from southern Morocco, northwestern Mauritania, the Byzantine Empire and Central Europe.
The discovery of copper metallurgy in the Akjoujt region in Mauritania and the Eghazzer basin dated to the second and early first millennium BCE shook the foundation of that consensus. In all the other areas reviewed in this article, however, iron metallurgy was adopted directly by Late Stone Age mixed-farming and horticulturalist communities.
A general outline of the origins of African copper metallurgy is presented by Michael S. Bisson . Native copper was exploited for one to two millennia. “The mining and smelting of copper ore appears to have arisen independently in Asia Minor, Eastern Europe, and Egypt between 5000 and 4000 BC”
. He outlines a number of elements suggesting a link between the Akjoujt copper metallurgy, Western Europe Early Bronze Age, and Phoenician North Africa. First, the large proportion of utilitarian objects tends to suggest that copper technology was introduced in the area as a package, in contrast to all cases of early metallurgy development in which status objects are dominant. Second, there are striking stylistic similarities between Mauritanian, North African, and Iberic Peninsula copper artifacts. He concludes that the presence of more prosaic copper artifacts at the beginning of the Mauritanian sequence suggests that the technology may have its roots elsewhere.”
The cases from the Eghazzer basin that point to the late third–early second millennium BCE age of copper smelting are still strongly debated. Egypt was suggested as the most likely initial source of the Eghazzer copper metallurgy: It is not inconceivable that communications, however indirect and periodic, between the Nile Valley and interior Sahara regions occurred over a long period and that the knowledge of working with metals (particularly copper) was along the numerous routes to the west, southwest and south. Iron technology may have been introduced along similar networks by the turn of the first millennium BC, although additional stimulus was provided by the new links to the northern coast.
In West Africa, there is a great deal of documentation about copper in trade, but the travelers who wrote these documents only visited the major centers of West African polities and there is no information on the people who lived out the polities or from the savanna and forest zones to the south, in terms of their use of copper. Arab and European trader documented that the principal goods that were in demand in West African markets were salt and copper. There has been a lack of research done in the savannah and forest regions of West Africa so the evidence of the diffusion copper there is spotty at best. Despite West Africa's rich gold resources, high status people were most often buried with copper grave goods. The only sites prior to 1500 AD to have gold were Djenné, Tedaoust, and several tumuli in Senegal.
Central and South Africa
In West Africa, copper was used as medium of exchange, symbols of status and kingship, jewelry, and ritual purposes; this was a part of Bantu tradition prior to their expansion into Central Africa. The use of copper in the Iron Age of Central Africa was produced because of indigenous or internal demand rather than those from outside, and it is thought to be a sensitive sign of political and social change.
Copper appeared to be a prestigious metal in Central and Southern Africa. In Central Africa copper has been found in places where copper is not produced, implying some sort of commerce. Also the majority of artifacts found suggest that the primary use for copper in the area was for decorative purposes. The available evidence shows that prior to fifteenth century Zimbabwean Iron Age site also placed higher value in copper than gold, though the date may have to be pushed with recent carbon dates.
It is thought that through trade with India and later Portugal Zimbabwe started to value gold as prestige metal, however it did not replace copper. Archaeological and documentary sources may skew the record in favor of nonperishable elements of culture and not give enough credit to pastoral and mixed farming activities that were needed to sustain these Iron Age populations. They do make it clear that copper was an important part of the exchange economies of Central and Southern Africa. The site of Bosutswe is evidence that copper and other precious metals were vital to trade in the area.
Tswana towns of the pre-colonial period in South Africa, such as the Tlokwa capital at Marothodi near the Pilanesberg National Park, demonstrate a continuation of native copper production into the early nineteenth century. In this period, archaeological research suggests that copper production had intensified significantly to meet growing regional demands.
East Africa
Copper is almost non-existent for most of the interior of East Africa, with a few exceptions particularly Kilwa and medieval sites in Nubia and Fostat, and there is not enough information yet to reconstruct copper on the Swahili Coast.
Symbolism
Bisson (2000) thought that because of copper's redness, luminosity and sound, it was valued by Africans. For many African cultures, the redness could be with life giving powers. Bisson (2000) also noted that the redness is a symbol of transition and it association with transition could explain why the wide use of copper in rituals in various African states. Also, its ability to reflect sunlight is suggested represent aggression and liminal boundaries between states, thus emphasizing its transformative properties. Finally, because of copper's use in bells and drums, it is thought to aid in the summoning spirits, when the instruments are played.
See also
Iron metallurgy in Africa
Metallurgy during the Copper Age in Europe
References
Bibliography
Copper mining in Africa
Economic history of Africa
History of metallurgy
Science and technology in Africa
Archaeology of Central Africa
Archaeology of Southern Africa
Archaeology of Western Africa
Archaeology of Eastern Africa
Chalcolithic | Copper metallurgy in Africa | Chemistry,Materials_science | 2,294 |
76,916 | https://en.wikipedia.org/wiki/Methyl%20isocyanate | Methyl isocyanate (MIC) is an organic compound with the molecular formula CH3NCO. Synonyms are isocyanatomethane and methyl carbylamine. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides and Haffmann Bromamide Degradation (such as carbaryl, carbofuran, methomyl, and aldicarb). It has also been used in the production of rubbers and adhesives. As an extremely toxic and irritating compound, it is very hazardous to human health. MIC was the principal toxicant involved in the Bhopal gas disaster, which short-term killed 4,000–8,000 people and caused permanent injury and premature deaths to approximately 15,000-20,000. It is also a very potent lachrymatory agent.
Physical properties
Methyl isocyanate is a colorless, poisonous, lachrymatory (tearing agent), flammable liquid. It is soluble in water to 6–10 parts per 100 parts, but it also reacts with water (see Reactions below).
It has a refractive index of 1.363 with a wavelength of 589 nm at a temperature of 20 °C
Manufacture
Methyl isocyanate is usually manufactured by the reaction of monomethylamine and phosgene. For large-scale production it is advantageous to combine these reactants at higher temperature in the gas phase. A mixture of methyl isocyanate and two moles of hydrogen chloride is formed, but N-methylcarbamoyl chloride (MCC) forms as the mixture is condensed, leaving one mole of hydrogen chloride as a gas.
The methyl isocyanate is obtained by treating the MCC with a tertiary amine, such as N,N-dimethylaniline, or with pyridine, or by separating it by using distillation techniques.
Methyl isocyanate is also manufactured from N-methylformamide and air. In the latter process, it is immediately consumed in a closed-loop process to make methomyl. Other manufacturing methods have been reported.
Reactions
Methyl isocyanate reacts readily with many substances that contain N-H or O-H groups. With water, it forms 1,3-dimethylurea and carbon dioxide with the evolution of heat (1358.5 joules, or 325 calories, per gram of MIC): It is relatively slow to react at below 68 °F, but will increase its rate with elevated temperatures or in the presence of acid or base.
At 25 °C, in excess water, half of the MIC is consumed in 9 min.; if the heat is not efficiently removed from the reacting mixture, the rate of the reaction will increase and rapidly cause the MIC to boil. Such a reaction triggered the Bhopal disaster after a large amount of water was introduced to a MIC storage tank. The consequence of the out of control exothermic process was a runaway reaction and the direct release of 42 tons of MIC to the atmosphere.
If MIC is in excess, 1,3,5-trimethylbiuret is formed along with carbon dioxide. Alcohols and phenols, which contain an O-H group, react slowly with MIC, but the reaction can be catalyzed by trialkylamines or dialkyltin dicarboxylate. Oximes, hydroxylamines, and enols also react with MIC to form methylcarbamates. These reactions produce the products described below (Uses).
Ammonia, primary, and secondary amines rapidly react with MIC to form substituted ureas. Other N-H compounds, such as amides and ureas, react much more slowly with MIC.
It also reacts with itself to form a trimer or higher-molecular-weight polymers. In the presence of catalysts, MIC reacts with itself to form a solid trimer, trimethyl isocyanurate, or a higher-molecular-weight polymer:
Sodium methoxide, triethyl phosphine, ferric chloride and certain other metal compounds catalyze the formation of the MIC-trimer, while the high-molecular-weight polymer formation is catalyzed by certain trialkylamines. Since the formation of the MIC trimer is exothermic (1246 joules, or 298 calories, per gram of MIC), the reaction can lead to violent boiling of the MIC. The high-molecular-weight polymer hydrolyzes in hot water to form the trimethyl isocyanurate. Since catalytic metal salts can be formed from impurities in commercial grade MIC and steel, this product must not be stored in steel drums or tanks.
Toxicity
Methyl isocyanate is extremely toxic. There is no known antidote. The threshold limit value set by the American Conference of Governmental Industrial Hygienists is 0.02 ppm. MIC is toxic by inhalation, ingestion and contact in quantities as low as 0.4 ppm. Exposure symptoms include coughing, chest pain, dyspnea, asthma, irritation of the eyes, nose and throat, as well as skin damage. Higher levels of exposure, over 21 ppm, can result in pulmonary or lung edema, emphysema and hemorrhages, bronchial pneumonia and death. Although the odor of methyl isocyanate cannot be detected at 5 ppm by most people, its potent lachrymal properties provide an excellent warning of its presence (at a concentration of 2–4 parts per million (ppm) subjected to eyes are irritated, while at 21 ppm, subjects could not tolerate the presence of methyl isocyanate in air). The irritant effects of methyl isocyanate are mediated by the irritant and tear gas receptor TRPA1 in pain-sensing nerve endings in the eye.
Proper care must be taken to store methyl isocyanate because of its ease of exothermically polymerizing (see Reactions) and its similar sensitivity to water. Only stainless steel or glass containers may be safely used; the MIC must be stored at temperatures below and preferably at .
The toxic effect of the compound was apparent in the 1984 Bhopal disaster, when around of methyl isocyanate and other gases were released from the underground reservoirs of the Union Carbide India Limited (UCIL) factory, over a populated area on 3 December 1984, killing about 3,500 people immediately, 8,000 people in the first 48 hours and 15,000 more over the next several years. 200,000 people had lasting health effects from the disaster.
During structural fires, natural materials can contribute to releasing isocyanates including methyl isocyanate.
Mechanism of action
Until recent decades, the mechanism of methyl isocyanate toxicity in humans was largely unknown or unclear. Methyl isocyanate and other isocyanates are electrophiles and are currently thought to cause toxicity by the alkylation of biomolecules. The mechanism of methyl isocyanate was previously suspected to be the carbamylation of hemoglobin, thus interfering with its oxygen-binding capability and causing hypoxia. However, experiments showed that when rats and guinea pigs were exposed to methyl isocyanate at concentrations above the median lethal concentration (LC50, the concentration sufficient to kill 50% of the tested population), only 2% of hemoglobin molecules were carbamylated, suggesting that this is probably not the mechanism of toxicity.
Extraterrestrial occurrence
On 30 July 2015, scientists reported that upon the first touchdown of the Philae lander on comet 67/P surface, measurements by the COSAC and Ptolemy instruments revealed sixteen organic compounds, four of which were seen for the first time on a comet, including acetamide, acetone, methyl isocyanate and propionaldehyde.
In 2017, two teams of astronomers using the Atacama Large Millimeter Array (ALMA) interferometer made of 66 radio telescopes in the Atacama Desert (northern Chile) have discovered the presence of MIC around young Sun-like stars.
MIC is considered a prebiotic molecule as explained by the discoverers of the ALMA findings in IRAS 16293-2422, a multiple system of very young stars: "This family of organic molecules is involved in the synthesis of peptides and amino acids, which, in the form of proteins, are the biological basis for life as we know it".
References
External links
NIOSH Safety and Health Topic: Isocyanates, from the website of the National Institute for Occupational Safety and Health (NIOSH).
U.S. National Library of Medicine: Hazardous Substances Databank – Methyl isocyanate
Isocyanates
Monomers
Bhopal disaster
Pulmonary agents
Lachrymatory agents
Prebiotic chemistry
Methyl compounds | Methyl isocyanate | Chemistry,Materials_science,Biology | 1,826 |
40,423,322 | https://en.wikipedia.org/wiki/Niphimycin | Niphimycin is an antimicrobial made by Streptomyces.
References
Antimicrobials | Niphimycin | Chemistry,Biology | 26 |
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