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74,426,975 | https://en.wikipedia.org/wiki/Tuber%20excavatum | Tuber excavatum, the hollowed truffle, is a species of truffle in the family Tuberaceae. The species is found in western Europe.
References
Fungi described in 1831
Fungi of Europe
excavatum
Truffles (fungi)
Fungus species | Tuber excavatum | [
"Biology"
] | 58 | [
"Fungi",
"Fungus species"
] |
74,430,591 | https://en.wikipedia.org/wiki/Pool%20skimmer | A skimmer or surface separator (it separates substances from the surface of a liquid) is an essential accessory for the maintenance and cleaning of the water in a swimming pool. It is used to remove all the surface dirt floating on the water surface, such as leaves, tanning oil and human secretions. These impurities remain suspended on the surface, affect the appearance of the water and are not always removed by the conventional vacuuming process. The skimmer is installed directly in the surface water suction system and also has the function of controlling the water level to prevent accidental overflows. In the United States and Portugal, the use of skimmers in the construction of swimming pools is mandatory, regulated and standardized by competent bodies.
Types
There are different types of skimmers that can be used for different purposes. The most common types of skimmers include:
Manual skimmers: These are basic skimmers that consist of a strong net strung on the end of a long pole. They are used to remove waste and pollutants from the surface of the water.
Automatic skimmers: These are the most common variety of skimmers and the one you will most likely see running in any given pool. They are installed at surface level and are designed to remove debris and contaminants from the surface of the water.
Standalone skimmers: These skimmers are designed to be used in conjunction with a pump and filter system. They are installed at surface level and are designed to remove debris and contaminants from the surface of the water
Drainage opening
Typically a skimmer draws water from the pool through a rectangular opening in the wall, at the top of the pool, connected through a device installed in one (or more) walls of the pool. The internal parts of the skimmer are accessed from the pool deck through a circular or rectangular cover, approximately one foot in diameter. If the pool's water pump is operational, it draws water from the pool through a hinged floating chute (which operates from a vertical position at a 90-degree angle to the pool, to prevent leaves and debris from being washed back into the pool by wave action), and down into a removable "skimmer basket", whose purpose is to catch leaves, dead insects and other larger floating debris.
The opening visible from the side of the pool is usually 1'0" (300 mm) wide by 6" (150 mm) high, which cuts the water halfway down the center of the opening. Skimmers with wider openings are called "wide angle" skimmers and can be up to 2'0" wide (600 mm). Floating skimmers have the advantage of not being affected by water level, as they adjust to work with the suction rate of the pump and will maintain optimal skimming regardless of water level, leading to a significantly reduced amount of biomaterial in the water. Skimmers should always have a leaf basket or filter between it and the pump to avoid clogging the pipes leading to the pump and filter.
Consecutive dilution
A consecutive dilution system is usually provided to remove the organic waste in stages after passing through the skimmer. The waste material is trapped within one or more sequential skimmer basket sieves, each with a finer mesh to further dilute the size of the contaminant. Dilution here is defined as the act of making something weaker in strength, content or value.
The first basket is placed very close to the mouth of the skimmer. The second is connected to the circulation pump. Here 25% of the water drawn from the main drain at the bottom of the pool meets 75% drawn from the surface. The circulation pump sieve basket is easily accessible for maintenance and should be emptied daily. The third sieve is the sand unit. Here the smallest organic waste that has slipped through the previous sieves is trapped by the sand.
If not removed regularly, organic waste will continue to decompose and affect water quality. The dilution process makes it easy to remove organic waste. Ultimately, the sand screen can be backwashed to remove smaller trapped organic debris that otherwise leaches ammonia and other compounds into the recirculated water. These additional solutes eventually lead to the formation of disinfection byproducts (DBPs). The sieve baskets are easily removed each day for cleaning, as is the sand unit, which should be backwashed at least once a week. A perfectly maintained back-to-back dilution system dramatically reduces the build-up of chloramines and other DBPs. The water returned to the pool must have been cleaned of all organic debris larger than 10 microns in size.
Recirculation jets
Return water from the consecutive dilution system passes through subsurface return jets. These are designed to impact a turbulent flow as the water enters the pool. This flow as a force is much smaller than the mass of water in the pool and takes the path of least pressure upwards where eventually the surface tension reforms it into a laminar flow at the surface.
As the returned water disturbs the surface, it creates a capillary wave. If the return jets are positioned correctly, this wave creates a circular motion within the surface tension of the water, allowing the surface to slowly circulate around the pool walls. Organic debris that floats to the surface through this capillary wave circulation slowly passes through the skimmer mouth, where it is attracted by laminar flow and surface tension over the skimmer dump. In a well-designed pool, the circulation caused by disturbed return water helps remove organic debris from the pool surface and directs it to be trapped within the back-dilution system for easy disposal.
Some return jets are equipped with a rotating filter. Used correctly, it induces deeper circulation, cleaning the water even more. Rotating the jet filters at an angle imparts rotation within the entire depth of the pool water. Orientation to the left or to the right would result in a clockwise or counterclockwise rotation, respectively. This has the advantage of cleaning the bottom of the pool and slowly moving the sunken inorganic debris into the main drain, where it is removed by the circulator basket screen.
In a properly constructed pool the circulation of water caused by the way it returns from the back-dilution system will reduce or even eliminate the need to vacuum the bottom. To obtain maximum rotational force on the main body of water, the back-to-back dilution system must be as clean and unblocked as possible to allow maximum flow pressure from the pump. As the water swirls, it also disturbs the organic debris in the lower layers of the water, forcing it up. The rotational force created by the pool's return jets is the most important part of cleaning the pool water and pushing organic debris through the skimmer mouth.
If the pool is designed and operated correctly, this circulation is visible and, after a period, reaches even the deepest end, inducing a low-speed vortex over the main drain due to suction. Correct use of return jets is the most effective way to remove disinfection byproducts caused by deeper decaying organic debris and bring them into the back-to-back dilution system for immediate disposal.
Additional sanitation methods
Salt chlorination units, electronic oxidation systems, ionization systems, microbial disinfection systems with ultraviolet lamps and Tri-Chlor Feeders are other independent or auxiliary systems of skimmers for pool sanitation. Apart from this, the temperature of the water is very important, since if it remains high, it favors the proliferation of algae.
Mineral disinfectants
Mineral disinfectants for pools and spas use minerals, metals, or elements derived from the natural environment to produce water quality benefits that would otherwise occur with harsh or synthetic chemicals .
Companies cannot sell a mineral disinfectant in the United States unless it has been registered with the US Environmental Protection Agency (EPA). Two mineral disinfectants are currently registered with the EPA: one is a silver salt with a controlled release mechanism that is applied to calcium carbonate granules that help neutralize pH; the other uses a colloidal form of silver released into water from ceramic beads.
Mineral technology takes advantage of the cleaning and filtering qualities of common substances. Silver and copper are well-known oligodynamic substances that are effective in destroying pathogens. Silver has been shown to be effective against harmful bacteria, viruses, protozoa and fungi . Copper is widely used as an algaecide. Alumina derived from aluminates filters harmful materials at the molecular level and can be used to control the rate of delivery of desirable metals such as copper. Working through the pool or spa's filtration system, mineral disinfectants use combinations of these minerals to inhibit algae growth and remove contaminants.
Unlike chlorine or bromine, metals and minerals do not evaporate and do not degrade. Minerals can make water noticeably softer and, by replacing harsh chemicals in water, reduce the possibility of red eyes, dry skin and bad odors.
Oil and grease on the surface
The density of fresh water is 1,000 kilograms per cubic meter, while the density of seawater varies between 1,020 and 1,030 kilograms per cubic meter. Oil is less dense than fresh water and seawater, so it floats in both types of water, but due to the difference in density the oil and fat particles, dispersed in the water, will reach the surface more quickly in a saltwater or seawater pool, being in both cases, "the only possible means" to remove them, to recirculate the water surface through skimmers .
References
External links
Automatic Skimmer Robotic Pool Cleaner
Swimming pool equipment
Cleaning | Pool skimmer | [
"Chemistry"
] | 1,999 | [
"Cleaning",
"Surface science"
] |
74,431,337 | https://en.wikipedia.org/wiki/Pal-Kal | Pal-Kal () was a construction method for concrete ceilings, invented by engineer Eli Ron in the late 1970s (Israel Patent No. 104,101).
The Pal-Kal method offered an easier, faster, and cheaper solution for casting ceilings compared to traditional reinforced concrete slabs. However, certain applications of this method were proven to be extremely dangerous, and the use of non-standard Pal-Kal ceilings was the main cause of the collapse of the Versailles wedding hall disaster.
Construction method
The basic principle of the Pal-Kal method involved using galvanized steel boxes inside the concrete, replacing the steel rods intended for reinforcement against bending and the upper reinforcement rods. The shape of the concrete poured between the steel boxes was similar to that obtained in a regular ribbed ceiling. In some Pal-Kal ceilings, there was also a thin layer of concrete underneath. The galvanized boxes were placed with the opening facing downwards and with spaces between them. The concrete was poured between and above the boxes. The boxes created air spaces within the ceiling while providing sufficient static thickness. The galvanized steel acted as formwork and also served as reinforcement against bending. In some non-standard Pal-Kal ceilings, the boxes replaced the reinforcement stirrups designed to prevent shearing.
Various versions of the Pal-Kal construction were developed over time, with different combinations of galvanized boxes and different concrete sections, with or without additional steel reinforcement:
Pal-Kal ceiling in a T-section with standard reinforcement stirrups and horizontal reinforcement in its bottom thin layer of concrete.
Pal-Kal ceiling in an I-section with standard reinforcement stirrups.
Pal-Kal ceiling in an I-section without reinforcement stirrups.
Pal-Kal ceiling in an I-section with non-compliant reinforcement stirrups.
Versions 1 and 2 included reinforcement stirrups that provided shear resistance, and such ceilings were considered standard. Versions 3 and 4, without reinforcement stirrups, were non-standard and even hazardous.
Construction process of Pal-Kal ceilings began with the pouring of a very thin layer of non-structural concrete with minimal reinforcement. The role of this concrete was not structural. Above or into this initial concrete layer, the galvanized boxes were inserted in the shape of the letter 'ח' (Chet in Hebrew). Then, additional concrete was poured above the boxes to create the final rigid ceiling. The galvanized steel's function was to ensure better adhesion between it and the concrete.
Problems
Lack of shear resistance: The galvanized boxes could not withstand shear forces as designed reinforcement stirrups would. The attachment of the boxes to the initial thin concrete layer was weak and imprecise. In a later version of Pal-Kal, additional shear reinforcement in the form of a ladder was added, but it was not adequately anchored to provide its intended constructive role.
Carrying capacity of the lower concrete layer, with its thickness of about 5–6 cm, was compromised once the boxes were inserted.
The quality of galvanized steel used in Pal-Kal was much lower compared to standard steel used for reinforcement in concrete.
Corrosion issues: The air spaces created within the ceiling allowed for the accumulation of water, leading to corrosion without visible signs.
Construction of Pal-Kal ceilings involved multi-stage pouring with significant time gaps between them. If the second pouring was delayed by even a few hours, the initially poured concrete would set partially, creating a weak point in the concrete (whose strength could not be measured).
Pal-Kal ceilings did not allow early detection of problems like cracks and corrosion.
Versailles wedding hall disaster
In 2001, a Pal-Kal ceiling collapsed while guests were dancing on it at the Versailles wedding hall in Jerusalem, resulting in the death of 23 people. The collapse was caused by multiple factors, including the non-standard construction of the ceiling. Shortly before the disaster, a wall supporting the ceiling on the second floor was removed, allowing the ceiling to start sinking. During the wedding, additional weight was added when people were dancing, leading to the sudden collapse of the structure.
Following the disaster, legal actions were taken against those responsible. The hall owners were found guilty of manslaughter and received two and a half years of imprisonment. Eli Ron, the engineer who invented the Pal-Kal method, and three other engineers were also found guilty of manslaughter. The engineers received a sentence of 22 months, while Eli Ron was sentenced to four years in prison.
Safety certification
Pal-Kal structures deemed unsafe are forbidden for use and are often demolished. To prevent unnecessary demolitions, safety tests can be conducted on the structure. A Pal-Kal structure that passes this test is as safe as buildings constructed using traditional methods. Nowadays, most municipalities require annual safety checks to detect potential problems in Pal-Kal structures. However, some engineers argue that a single safety test is sufficient and annual checks are unnecessary.
Additional buildings
Following the Versailles disaster, other buildings constructed using the Pal-Kal method were inspected, and some of them were closed for use until repairs were completed. In certain buildings, the cost of these repairs reached millions of shekels.
See also
Architecture of Israel
References
Construction
Construction standards | Pal-Kal | [
"Engineering"
] | 1,070 | [
"Construction",
"Construction standards"
] |
74,433,533 | https://en.wikipedia.org/wiki/Synchroma | Synchroma () is a genus of marine stramenopile algae containing two species with amoeboid morphology. They are grouped within the monotypic family Synchromaceae and order Synchromales as part of an independent clade of ochrophytes known as Picophagea or Synchromophyceae.
They are distinguished by their plastid complexes, composed of several chloroplasts grouped together and collectively enveloped by the same membranes. Within their life cycle, Synchroma cells are usually sessile and protected by a lorica. These cells can join their reticulopodia in a network known as meroplasmodium, or they can become migrating amoebae capable of fusing to each other.
Cellular structure
Synchroma are eukaryotic algae composed of amoeboid cells with no flagella and multiple yellowish-green chloroplasts containing chlorophyll a and c2, fucoxanthin, violaxanthin, antheraxanthin, zeaxanthin and b-carotene. Each cell presents plastid complexes of 6-8 chloroplasts each. Within the complexes, the pigmented lobes of the chloroplasts radiate from the center. Each pigmented lobe has longitudinally arranged lamellae, without a girdle lamella (i.e. a peripherical lamella that surrounds all other lamellae, characteristic of some ochrophytes). In the center of the complex, the non-pigmented pyrenoids of all chloroplasts are tightly grouped and surrounded by a single vesicle. Each chloroplast is surrounded by two 'inner' membranes, while the entire plastid complex is surrounded by two 'outer' membranes, with the outermost membrane as the rough endoplasmic reticulum.
Life cycle of Synchroma
Sessile stages and meroplasmodium
The main appearance of Synchroma is as sessile, amoeboid cells of around 16 or 22 μm in diameter on average, depending on the culture conditions. The cell body is attached through cytoplasmic strands to a flattened spherical lorica, 26 μm in diameter, which in turn is attached to the substrate. Multiple sessile cells can form a meroplasmodium, an association of several spherical cell bodies through a common network of reticulopodia, which allows the capture and transport of food particles. The sessile cells can undergo binary cell division (asexual reproduction).
Another sessile stage of Synchroma is the cyst, a spherical cell with a highly granular cytoplasm and no reticulopodia, surrounded by a multilayered cell wall. This has been interpreted as the resting stage of Synchroma, sometimes occurring within a lorica.
Non-sessile stages and aggregates
After binary cell division of a sessile Synchroma cell, while one of the daughter cells remains in the lorica, the other one hatches through the opening and becomes a migrating amoeba. These migrating cells without a lorica have a dynamic cell shape and size, capable of stretching and reaching five times their initial length. When attached to the substrate, they appear flattened. Within minutes, they can begin to float on the medium and switch to a 'heliozoa'-like form, with a spherical cell shape and 6-30 axopodia, sometimes fixing to the substrate through one or two of these axopodia. The floating cells can switch back into the migrating amoebae. After some period of time, the hatched amoebae form a lorica and become sessile cells.
The migrating amoeboid cells can fuse by contacting their filopodia together, then fusing the ectoplasm of several cells, then fusing the endoplasm. The fused cells can become sessile by forming a lorica. If two cells merge, they can undergo karyogamy (sexual reproduction) and differentiate into a tetrad, and three or all four of the daughter cells can hatch out of the lorica. Large cell aggregates can reach over 60 μm in size.
Ecology
Synchroma cells feed by phagotrophy of bacteria and other algae such as Phaeodactylum tricornutum. The cytoplasmic strands attach to the prey cells and are then hauled toward the main cell body until they reach the lorica, where they are digested. The reticulopodia can absorb cytoplasmic material of other cells without killing them.
This marine genus of algae displays sessile and non-sessile cell stages within its life cycle, with a dominating sessile amoeboid stage. It is assumed that it lives mainly benthic on sublittoral rocks. The strong adhesion of the lorica on the substrate could prevent cells from being washed away.
Evolution
Synchroma is a genus of stramenopile algae belonging to the class Synchromophyceae, of which Picophagea is a synonym. The evolutionary origin of the plastid complexes found in Synchroma is still an enigma. Synchroma is the only case of multiplastidic stramenopile algae where the plastids are retained together in a common compartment.
Classification
Synchroma contains two species:
Synchroma grande
Synchroma pusillum
References
Taxa described in 2007
Ochrophyte genera
Ochrophyta | Synchroma | [
"Biology"
] | 1,159 | [
"Ochrophyta",
"Algae"
] |
74,433,644 | https://en.wikipedia.org/wiki/Rhenium%20trioxynitrate | Rhenium trioxynitrate, also known as rhenium(VII) trioxide nitrate, is a chemical compound with the formula ReO3NO3. It is a white solid that readily hydrolyzes in moist air.
Preparation and properties
Rhenium trioxynitrate is prepared by the reaction of ReO3Cl (produced by reacting rhenium trioxide and chlorine) and dinitrogen pentoxide:
ReO3Cl + N2O5 → ReO3NO3 + NO2Cl
The ReO3Cl can be replaced with rhenium heptoxide, however, this produces an impure product. This compound reacts with water to produce perrhenic acid and nitric acid.
When heated above 75 °C, it decomposes to rhenium heptoxide, nitrogen dioxide, and oxygen:
4 ReO3NO3 → 2 Re2O7 + 2 NO2 + O2
A graphite intercalation compound can be produced by reacting a mixture of rhenium trioxynitrate and dinitrogen pentoxide with graphite.
Structure
X-ray diffraction and IR spectroscopic evidence rejects the formulations NO2+ReO4– or Re2O7·N2O5, but instead suggests a polymeric structure with a monodentate nitrate ligand.
References
Rhenium compounds
Nitrates | Rhenium trioxynitrate | [
"Chemistry"
] | 289 | [
"Oxidizing agents",
"Nitrates",
"Salts"
] |
74,435,162 | https://en.wikipedia.org/wiki/Major%20Baltic%20inflow | The Baltic Sea saltwater inflow, known as the major Baltic inflow (MBI), refers to a significant influx of saline water from the North Sea into the Baltic Sea through the Danish straits. In the Baltic Sea, dense seawater from the North Sea sinks to the bottom and moves along the seabed, displacing the often oxygen-depleted water in the deep basins. Simultaneously, it transports new oxygen-rich water to the deep basins. These inflows are crucial for the Baltic Sea's ecosystem because they alleviate the oxygen depletion that commonly occurs in the deep basins of the poorly mixed sea, and at the same time, they prevent eutrophication caused by internal nutrient loading.
The process for MBI formation
The water in the Baltic Sea is brackish, meaning it has a low salinity. Each year, approximately 550 km3 of freshwater from rainfall and rivers within its drainage basin flow into the Baltic Sea. However, only about 100 km3 of water evaporates from the Baltic Sea into the atmosphere annually. This results in an excess of approximately 450 km3 of fresh water each year, which accounts for about two percent of the total volume of the Baltic Sea. To maintain a stable water level over the long term, the excess water flows out of the Baltic Sea through the Danish straits into the North Sea. Periodic counterflow from the North Sea to the Baltic Sea prevents the Baltic from gradually turning into a freshwater basin.
The saltwater inflow, known as the major Baltic inflow (MBI), is said to occur when there is a strong overflow of saline water from the North Sea to the Baltic Sea over the cross-sections of the Darss Sill (Belt Sea) and the Drogden Sill (The Sound). Such a flow almost entirely destroys the salinity stratification in the areas of the sills for several days. Typically, the inflow event must last for at least five days to be classified as an MBI. During extremely powerful events, the Baltic Sea receives over 100 km3 of very saline water from the ocean, whereas during weaker MBIs, the volume is less than 100 km3, averaging around 70 km3.
Major Baltic inflows primarily occur during winter and early spring because weather conditions are most favorable for the inflow of saline water. First, the Baltic Sea must experience easterly and southeasterly winds for about 20 to 30 days, reducing precipitation within the Baltic Sea drainage basin, enhancing outflow from the basin, and causing a drop in the sea level. Before the arrival of the saline inflow, the Baltic Sea's surface level is typically around 26 centimeters lower than usual. Following this, a roughly one-month period of westerly winds begins, during which the sea level in the Kattegat rises, and pressure differences force the saline water from the North Sea through the narrow Danish straits into the Baltic Sea. Throughout the entire inflow process, the Baltic Sea's water level rises on average by about 59 cm, with 38 cm occurring during the preparatory period and 21 cm during the actual saline inflow. The MBI itself typically lasts for 7–8 days.
Occurrence of MBIs
The formation of an MBI requires specific, relatively rare weather conditions. Between 1897 and 1976, approximately 90 MBIs were observed, averaging about one per year. Occasionally, there are even multi-year periods without any MBIs occurring. Large inflows that effectively renew the deep basin waters occur on average only once every ten years.
Very large MBIs have occurred in 1897 (330 km3), 1906 (300 km3), 1922 (510 km3), 1951 (510 km3), 1993/94 (300 km3), and 2014/2015 (300 km3). Large MBIs have on the other hand been observed in 1898 (twice), 1900, 1902 (twice), 1914, 1921, 1925, 1926, 1960, 1965, 1969, 1973, 1976, and 2003. The MBI that started in 2014 was by far the third largest MBI in the Baltic Sea. Only the inflows of 1951 and 1921/1922 were larger than it.
Previously, it was believed that there had been a genuine decline in the number of MBIs after 1980, but recent studies have changed our understanding of the occurrence of saline inflows. Especially after the lightship Gedser Rev discontinued regular salinity measurements in the Belt Sea in 1976, the picture of the inflows based on salinity measurements remained incomplete. At the Leibniz Institute for Baltic Sea Research (Warnemünde, Germany), an updated time series has been compiled, filling in the gaps in observations and covering Major Baltic Inflows and various smaller inflow events of saline water from around 1890 to the present day. The updated time series is based on direct discharge data from the Darss Sill and no longer shows a clear change in the frequency or intensity of saline inflows. Instead, there is cyclical variation in the intensity of MBIs at approximately 30-year intervals.
Effects on the state of the Baltic Sea and its ecosystem
Major Baltic inflows (MBIs) are the only natural phenomenon capable of oxygenating the deep saline waters of the Baltic Sea, making their occurrence crucial for the ecological state of the sea. The salinity and oxygen from MBIs significantly impact the Baltic Sea's ecosystems, including the reproductive conditions of marine fish species such as cod, the distribution of freshwater and marine species, and the overall biodiversity of the Baltic Sea.
The heavy saline water brought in by MBIs slowly advances along the seabed of the Baltic Proper at a pace of a few kilometers per day, displacing the deep water from one basin to another. Although some oxygen is transported from the North Sea to the Baltic Sea, only a small portion of the oxygen responsible for renewing the deep basins originates from the Baltic Sea entrance area. In the southwestern basins of the Baltic Sea (Arkona sea, Bornholm basin), there is already oxygen present in the water column, and the role of the saltwater pulse is to entrain and direct it towards the deep basins of the sea.
It has been observed that the oxygen supplied by saline inflows is consumed more rapidly in the Baltic Proper than before. In 1993, the oxygen replenishment was depleted in about 17 months, in 2003, it took approximately 13 months, and in 2015, it was exhausted in just six months.
The intense oxygen consumption in the Baltic Sea's seafloor is due to prolonged nutrient loading and the impacts of climate change. Although a single MBI can oxygenate both the deep water hydrogen sulfide and ammonia, multiple consecutive inflows would be required to raise the oxygen level to a satisfactory level. The so-called "oxygen debt" was estimated to be about 20 million tons in 2020. This is the amount of oxygen that should be transported to the Baltic Proper via saline inflows to raise its oxygen concentration to the 3 mL/L level observed after the MBI of 1993. With a single 200 km3 MBI, approximately 2 million tons of oxygen are transported.
References
Baltic Sea
Oceanography | Major Baltic inflow | [
"Physics",
"Environmental_science"
] | 1,469 | [
"Oceanography",
"Hydrology",
"Applied and interdisciplinary physics"
] |
74,436,776 | https://en.wikipedia.org/wiki/Olympian%203 | Olympian 3, 'For Theron of Acragas', is an ode by the 5th century BC Greek poet Pindar.
Background
The third Olympian celebrates the same victory as the second (that of 476), but, while the former Ode was probably sung in the palace of Theron, the present was performed in the temple of the Dioscuri at Acragas, on the occasion of the festival of the Theoxenia, when the gods were deemed to be entertained by Castor and Polydeuces.
Summary
Acragas and Theron are commended to the favour of the Twin Brethren and their sister Helen (1–4). The Muse has prompted the poet to invent a new type of Dorian song, to be sung to the accompaniment of the lyre and the flute (4–9). He was also summoned to sing by Pisa, whence odes of victory are sent to all whom the umpire crowns with the olive, which Heracles brought back from the Hyperboreans to the treeless Olympia (9–34).
Heracles is now attending the Theoxenia with the Twin Brethren, whom he caused to preside over the Olympic Games (34–38). Theron's glory is a favour granted in return for his pious worship of the Twin Gods (38–41). Even as water and gold are supreme in their kind, so Theron's exploits reach the Pillars of Heracles.
References
Sources
Attribution:
Further reading
5th-century BC literature
Ancient Greek poems
Castor and Pollux | Olympian 3 | [
"Astronomy"
] | 322 | [
"Castor and Pollux",
"Astronomical myths"
] |
74,437,860 | https://en.wikipedia.org/wiki/Interim%20Measures%20for%20the%20Management%20of%20Generative%20AI%20Services | The Interim Measures for the Management of Generative AI Services () are a set of measures introduced by China to regulate public-facing generative artificial intelligence within the country. The measures took effect on 15 August 2023.
The measures were issued by the Cyberspace Administration of China, along with six other national regulators: the National Development and Reform Commission, the Ministry of Education, Ministry of Science and Technology, Ministry of Industry and Information Technology, Ministry of Public Security, and National Radio and Television Administration.
Articles
Section 1: General provisions
Article 1 outlines the intention of the measures: promoting the healthy development and regulated usage of generative AI, while safeguarding national security, societal public interests, and the legal rights of citizens and organizations.
Article 2 defines the scope of the measures as applying to public-facing generative AI services within the People's Republic of China. It exempts internal services by companies, research institutions, and other organizations that do not provide services to the domestic public.
Article 3 sets out key principles that will guide the regulatory approach: equal emphasis on development and security, promoting innovation along with rule of law, and adopting inclusive prudence with classified supervision of generative AI services.
Article 4 requires generative AI services to adhere to relevant laws and respect social morality. Adhering to the Core Socialist Values, they must not generate content that promotes overthrowing the socialist system, harms national security, or undermines social stability. They must not promote discrimination, terrorism, extremism, violence, obscenity, or false and harmful information prohibited by law. Models should be designed and trained to avoid discrimination or algorithmic bias. Services should respect intellectual property rights and business ethics. They must respect others' rights and avoid endangering the physical and mental health of others. Effective measures should be taken to improve the transparency and accuracy of generative AI services.
Section 2: Technology development and governance
Article 5 encourages innovative application of generative AI across industries to create positive, healthy and high-quality content. It supports collaboration on AI innovation, data and application development.
Article 6 promotes independent innovation in core AI technologies, infrastructure development, and data resource platforms. It encourages international cooperation, collaborative sharing of compute, expanding high-quality public training data sources, and the adoption of secure chips and resources.
Article 7 mandates that providers employ effective measures to ensure that training data is high-quality, accurate, diverse, and legitimately sourced in a way that does not infringe upon intellectual property rights. If personal information is used, the users must provide consent.
Article 8 requires providers to formulate clear, specific and operable data labeling rules in line with the measures. It mandates quality assessment, sampling verification, personnel training and supervision for labeling work.
Section 3: Service specifications
Article 9 legally establishes providers as producers of online content and processors of personal data. Providers should sign service agreements with users to define rights and obligations.
Article 10 mandates taking effective measures from excessive use by minors. Providers should clarify the appropriate use of their services to users and help users understand generative AI.
Article 11 obligates providers to protect user privacy, minimize data collection and retention of personal information, and avoid illegally giving user information to others. Providers should accept user requests to review, copy, modify, or delete their personal information.
Article 12 requires labeling synthesized pictures, videos and other generated content.
Article 13 requires stable and continuous services for normal usage by users.
Article 14 obligates providers to promptly address when a service generates illegal content or if it is used by users to engage in illegal activities. This may include halting generation, retraining a model, warning users, and reporting to a relevant authority.
Article 15 mandates complaint and reporting mechanisms for public grievances with timely processing and feedback.
Section 4: Supervision, inspection, and legal liability
Article 16 gives regulatory oversight roles to cybersecurity, technology, industry, education, public security and other relevant government bodies.
Article 17 requires security assessments for services with public opinion influence, along with algorithm filing procedures.
Article 18 allows users to complain to authorities about non-compliant services.
Article 19 enables inspections of providers by officials, requiring cooperation and transparency.
Article 20 allows the government to address foreign services that violate the measures.
Article 21 defines the relevant authorities that may punish providers that violate the provisions. Crimes will be investigated according to law.
Section 5: Supplementary provisions
Article 22 defines key terms such as generative AI, service providers, and service users.
Article 23 requires obtaining relevant licenses to provide services where required by law.
Article 24 establishes that the measures take effect on 15 August 2023.
References
External links
Full text (in Chinese)
Regulation of artificial intelligence
Law of the People's Republic of China | Interim Measures for the Management of Generative AI Services | [
"Technology"
] | 954 | [
"Computing and society",
"Regulation of artificial intelligence"
] |
74,438,085 | https://en.wikipedia.org/wiki/Ayya%20%28smartphone%29 | AYYA is a smartphone series developed by Rostec. The first and only device in the series is the AYYA T1 which released on 28 October 2021 with Android 11 and plans to upgrade to Aurora OS. The T1 sold poorly and was affected by a CPU chip undersupply issue due in part to the supplier TSMC halting trade with Russia in response to the 2022 invasion of Ukraine. It has a button which disables the microphone and cameras.
History
At the end of October 2021 the first sales of the AYYA T1 smartphone began in Russia. Then from the domestic smartphone, there was only software that is legally required for installation.
In March 2022 a modification of AYYA T1 appeared on the Aurora OS for legal entities (corporate customers).
In March 2023, the media reported that retail sales of the AYYA T1 smartphone did not exceed 1 thousand units in 2 years out of a batch of 5 thousand units produced.
Product series
AYYA T1: 19,000 rubles or $200 USD
6.56-inch screen, two main cameras (12 and 5 MP), a 13 MP front camera, a MediaTek Helio P70 processor, 4 GB of RAM, and 64 GB of built-in memory with 128 GB of expansion
AYYA T2 is under development
References
External links
Смартфон AYYA T1
Economy of Russia
Rostec | Ayya (smartphone) | [
"Technology"
] | 291 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
78,785,007 | https://en.wikipedia.org/wiki/489P/Denning | 489P/Denning is a Jupiter-family comet with an orbital period of 9.4 years. It was discovered by William Frederick Denning on 26 March 1894 but was subsequently lost until 2024, when asteroid was identified as the same object.
Observational history
William Frederick Denning was searching for comets from Bristol, England, when on 26 March 1894 he found a faint object in Leo Minor. The next few days the magnitude of the comet was reported to be about 11. The comet also featured a tail about 5 arcminutes long. The comet upon discovery had passed both the perihelion and closest approach to Earth and was becoming fainter. In April the comet was observed as very faint and elongated. Few observations were made in May. The comet was last detected on 5 June 1894. It is possible the comet experienced an outburst in 1894.
The first orbit was calculated by Lipót Schulhof with positions from 27 to 31 March and indicated a parabolic orbit with perihelion on 13 February 1894. However, by mid April he suspected that the comet deviated from the orbit. The first elliptical orbit he calculated, with positions from 27 March to 25 April, had a perihelion date of 9 February and an orbital period of 6.74 years. Other orbits calculated were 7.94 years by Lewis Boss, 6.79 years by Schulhof, 6.76 years by John Russell Hind, and 7.70 years by Hind.
The comet wasn't recovered and became lost. In 2024 it was noted that Mars-crossing asteroid , which was discovered by LINEAR on 17 April 2007 with an apparent magnitude of 18.7–19.5, had a comet-like orbit. Maik Meyer found that the asteroid's orbit was a good match with the proposed orbit of comet Denning. Images of the object by the Great Shefford Observatory from 18 and 19 April were re-examined and it appeared slightly elongated, with an aspect ratio of 3:2 when compared with nearby stars, and extending eastwards. Images obtained by the 1.82m telescope of the Dominion Astrophysical Observatory on 19 April 2007 when stacked showed a coma with a diameter of 5".3 and a faint, spike-like tail extending for 8 arcseconds. The apparitions from 1972 to 1997 weren't favorable. The 1963–4 apparition was favorable, however no plates were found.
During the 2025 apparition the comet is predicted to reach 18th magnitude.
Orbit
As a Jupiter family comet, 489P/Denning approaches closes to planet Jupiter. A close approach, at a distance of 0.071 AU took place in July 1830. During the 1894 apparition the comet had a perihelion distance of 1.15 AU and an orbital period of 7.42 years. An approach to Jupiter on 18 June 1925 at a distance of 0.24 AU raised the orbital period to 8.00 years and perihelion to 1.29 AU and a further approach on 8 November 1986 at a distance of 0.19 AU raised them to 9.31 years and 1.56 AU respectively.
During the 1894 apparition the comet passed 0.27 AU from Earth on 12 February. Other close encounters took place on 25 December 1908, at a distance of 0.62 AU, and on 29 January 1964 at a distance 0.47 AU.
References
External links
Periodic comets
0489
489P
18940326
Recovered astronomical objects | 489P/Denning | [
"Astronomy"
] | 714 | [
"Recovered astronomical objects",
"Astronomical objects"
] |
78,785,499 | https://en.wikipedia.org/wiki/Draupner%20wave | The Draupner wave, also known as the New Year's wave or Draupner freak wave, was a rare freak wave that was the first to be detected by a measuring instrument. The wave, determined to be in height, was recorded on 1 January 1995 at Unit E of the Draupner platform, a gas pipeline support complex located in the North Sea about southwest from the southern tip of Norway.
Background
The Draupner platform rig, located in the Norwegian North Sea and 16/11 offshore from Norway, was built to withstand a calculated 1-in-10,000-years wave with a predicted height of and was fitted with state-of-the-art sensors, including a laser rangefinder wave recorder on the platform's underside.
Accompanying storm
On 31 December, a low pressure system was located over Sweden, with a north-western motion. This system produced large waves over the North Sea, although none would be of significance. Early the next day, a polar low would form over the Norwegian portion of the North Sea, which produced heavy winds that would set up the formation of the Draupner wave.
Discovery
The wave itself was first detected at 15:24 UTC on 1 January 1995 by a downward-pointing laser beam located on the Draupner S platform. The laser beam recorded a rogue wave with a maximum wave height of . Peak elevation above still water level was . The reading was confirmed by the other sensors. The platform sustained minor damage in the event. In the area, the SWH at the time was about , so the Draupner wave was more than twice as tall and steep as its neighbors, with characteristics that fell outside any known wave model. The wave caused enormous interest in the scientific community.
Legacy
The platform sustained minor damage in the event. In the area, the SWH at the time was about , so the Draupner wave was more than twice as tall and steep as its neighbors, with characteristics that fell outside any known wave model. The wave caused enormous interest in the scientific community. The wave, one of the largest ever documented in the Atlantic Ocean, helped solidify the initial speculation that rogue waves did naturally occur, and as a result the wave would be heavily studied in the years following the event.
See also
List of rogue waves
Notes and footnotes
Notes
Footnotes
Sources
1995 in science
Waves
Water waves
Rogue wave incidents | Draupner wave | [
"Physics",
"Chemistry"
] | 489 | [
"Physical phenomena",
"Applied and interdisciplinary physics",
"Water waves",
"Waves",
"Motion (physics)",
"Physical oceanography",
"Fluid dynamics"
] |
78,786,790 | https://en.wikipedia.org/wiki/List%20of%20extrasolar%20planetary%20collisions | This is a list of collisions between exoplanets or planetesimals observed in extrasolar systems. These collisions are more common in young systems and are an important part in the growth of especially terrestrial planets from so-called planetary embryos. Detections of individual collisions are nevertheless rare and are detected via transits in the optical, infrared excess, silicate emission or via infrared brightening. Collisions are thought to be common in a type of debris disk, so-called extreme debris disks (EDD). Co-moving stellar or substellar companions can trigger such collisions at an old age, creating old EDDs. Only about 24 EDDs are known.
This list does not include planetary bodies being accreted by white dwarfs, for this refer to the List of exoplanets and planetary debris around white dwarfs.
List of individual events
This list contains systems with individual collision events that were directly observed. Alternatively events were inferred from properties of the disk. The list is sorted after the start of the event.
List of other EDDs
These objects appear as EDDs in Moór et al. EDDs are listed here, because they are often associated with individual giant collisions. List is sorted after discovery year.
List of EDD without collisions
See also
List of stars that have unusual dimming periods
List of largest craters in the Solar System
Giant impact hypothesis
Mercury (planet) is thought to have lost its mantle from a collision
354P/LINEAR small asteroid that was impacted by another asteroid
References
Lists of stars
Circumstellar disks
Lists of exoplanets
Impact events | List of extrasolar planetary collisions | [
"Astronomy"
] | 321 | [
"Astronomical events",
"Impact events"
] |
78,786,868 | https://en.wikipedia.org/wiki/Taketaba | A was a Japanese type of bulletproof shield made from bundled bamboo.
Summary
During the Sengoku period, were found unable to stop the bullets used by the recently introduced arquebus.
The bullets used at the time were of very large caliber and thus had great destructive power, but their round shape and the lack of rifled barrels resulted in poor target penetration. Combined with the flexible strength of bamboo, this allowed taketaba to absorb and dissipate the energy of an arquebus shot. Because bamboo was in plentiful supply, taketaba were mass-produced and used throughout Japan.
The fastened large taketaba to the freeboard of their ships as a defense against cannon shot.
See also
Palisade
Abatis
Further reading
References
Medieval defences
Engineering barrages
Japanese inventions
Japanese bamboowork | Taketaba | [
"Engineering"
] | 164 | [
"Military engineering",
"Engineering barrages"
] |
78,788,573 | https://en.wikipedia.org/wiki/Procesi%20bundle | In algebraic geometry, Procesi bundles are vector bundles of rank on certain symplectic resolutions of quotient singularities, particularly on the Hilbert scheme of points in the complex plane. They play a fundamental role in geometric representation theory and were crucial in Mark Haiman's proof of the n! theorem and Macdonald positivity conjecture, and were named after Italian mathematician Claudio Procesi.
Definition
Let denote the Hilbert scheme of n points in the complex plane , which provides a resolution of singularities of the quotient , where is the symmetric group of degree . A Procesi bundle on is a -equivariant vector bundle of rank together with an isomorphism (where is the smash product algebra) of -algebras, such that for all . The isomorphism ensures that each fiber of is naturally the regular representation of .
More generally, for a finite subgroup and its wreath product , Procesi bundles can be defined on symplectic resolutions of .
Properties
Procesi bundles provide a derived McKay equivalence between the derived category of coherent sheaves on and the derived category of -equivariant modules over . For one distinguished Procesi bundle , the -invariants coincide with the tautological bundle on . On any symplectic resolution of , there are exactly two normalized (meaning ) Procesi bundles which are dual to each other.
History and constructions
The first construction of a Procesi bundle was given by American mathematician Mark Haiman in his proof of the n! theorem, using intricate combinatorial methods. Alternative constructions were later developed by Roman Bezrukavnikov and Dmitry Kaledin using quantization in positive characteristic, and by Victor Ginzburg using D-modules and the Hotta-Kashiwara construction.
Belarusian-American mathematician Ivan Losev provided significant further developments in the theory of Procesi bundles, including a complete classification of Procesi bundles on Hamiltonian reductions, and an inductive construction showing how Procesi bundles relate to nested Hilbert schemes. His work established that there are exactly two normalized Procesi bundles on any given symplectic resolution obtained by Hamiltonian reduction.
As a result of their use in the proof of the n! theorem, Procesi bundles have also found important applications in the proof of the Macdonald positivity conjecture, the study of rational Cherednik algebras and their representations, and understanding derived equivalences for symplectic quotient singularities.
See also
Derived category
Geometric invariant theory
Hilbert scheme
McKay correspondence
References
Algebraic geometry
Representation theory
Vector bundles | Procesi bundle | [
"Mathematics"
] | 524 | [
"Representation theory",
"Fields of abstract algebra",
"Algebraic geometry"
] |
78,789,026 | https://en.wikipedia.org/wiki/Herman%20Arend%20Ferguson | Herman Arend Ferguson (25 February 1911 – 10 April 1997) was a Dutch civil engineer and hydraulic engineer who contributed to water management in The Netherlands. He played a central role in the recovery efforts following the inundation of Walcheren in 1944, and the works to repair the significant damage caused by the North Sea flood of 1953. He held senior positions at Rijkswaterstaat, authored several key publications on hydraulic engineering, and was awarded the Order of the Netherlands Lion.
Life and career
Herman Arend Ferguson was born on 25 February 1911 in Voorburg, the son of George Ferguson and Francesca Hermina van den Brandhof. He was of Scottish ancestry. He graduated in 1938 with a degree in Civil Engineering from Delft University of Technology. After graduation, he joined Rijkswaterstaat (the Dutch Directorate-General for Public Works and Water Management), where he was employed in the (Study Department) of the (Directorate for the Lower Rivers).
During 1945–46, Ferguson was part of the (Service for the Reclamation of Walcheren), which was established to oversee the reclamation of the island of Walcheren after the intentional inundation of the island during World War II. The character Rafelding in the non-fiction novel Het verjaagde water by A. den Doolaard is based on Ferguson.
Afterwards, Ferguson moved to Vlissingen and worked for Rijkswaterstaat's (Service for Dike Repair Zeeland) following the North Sea flood of 1953. He became head of the (Hydraulic Engineering Division) of the Delta Service from 1956 to 1960, and subsequently headed the (Rotterdam Waterway District). Ferguson was appointed Chief Engineering Director of the (Directorate for the Lower Rivers, 1962–1969) and later of the Delta Service (1969–1976), where he contributed to significant water engineering projects, including the Delta Works and the improvement of the Nieuwe Waterweg.
Ferguson was deeply involved in the design and construction of the Haringvliet sluices, which were critical for water flow regulation and flood protection in the Rhine-Meuse-Scheldt Delta. He also contributed to the closure of tidal inlets including the Haringvliet and Brouwershavense Gat, major Delta Works schemes which were required to ensure that flood risks were mitigated.
Publications
Ferguson authored and contributed to numerous technical reports and publications over his career, including:
(Lower Rivers in the 1960s: Personal Memories of a Chief Engineer-Director, 1995)
(Dialogue with the North Sea, 1991), an exploration of the influence of human intervention on the Dutch Delta.
(Delta Vision: A Retrospective on Forty Years of Hydraulic Engineering in Southwest Netherlands, 1988)
(The Dutch Delta: A Compromise Between Environment and Technique in the Battle Against Water, 1983)
(Six-Barge Push Towage: A Study of General and Nautical Aspects, 1983)
(Note on the Concentration of Hydraulic Engineering Works in a Separate Service, 1972)
(Hydrological Changes in the Delta Region and Their Impact on Water Management, 1965)
(Wave Research in the Delta Region, 1959)
(Hydraulic Research for the Design and Construction of Closure Gaps in the Delta Dams, 1958)
(Salt Movement on the Rotterdam Waterway Especially During Low Surface Water Discharge, 1957)
(Restoration and Improvement Works After the Disaster of 1 February 1953, 1954)
(Report on the Condition of Banks and Beaches in Zeeland 1951 VI: Banks Along Keeten, Mastgat, and Zijpe, 1953)
(Report on Observations with the "Ocean" in the Mouth Area of the Western Scheldt, 1943)
(Introduction to Tide Calculation, 1943).
Most of these publications are maintained in electronic format by the Rijkswaterstaat archive.
Awards
Ferguson was awarded the Order of the Netherlands Lion, and his contributions to the scientific underpinning of the Delta Works Plan earned him an honorary doctorate from Delft University of Technology in 1987.
See also
Delta Works
Flood control in the Netherlands
Rijkswaterstaat
References
External links
Trésor der Hollandsche Waterbouw – Digital repository of publications by H.A. Ferguson
1911 births
1997 deaths
Dutch engineers
Hydraulic engineering
Delft University of Technology alumni
Academic staff of the Delft University of Technology
20th-century Dutch engineers | Herman Arend Ferguson | [
"Physics",
"Engineering",
"Environmental_science"
] | 875 | [
"Hydrology",
"Physical systems",
"Hydraulics",
"Civil engineering",
"Hydraulic engineering"
] |
78,789,446 | https://en.wikipedia.org/wiki/Anaprazole | Anaprazole is a pharmaceutical drug used for the treatment of duodenal ulcers. It is classified as a proton pump inhibitor (PPI). It was approved for use in China in 2023. It is formulated as its sodium salt, anaprazole sodium, in enteric-coated tablets.
References
Proton-pump inhibitors
Benzimidazoles
Benzofurans
Ethers
Sulfoxides
Methoxy compounds | Anaprazole | [
"Chemistry"
] | 91 | [
"Organic compounds",
"Functional groups",
"Ethers"
] |
78,789,767 | https://en.wikipedia.org/wiki/Atilotrelvir | Atilotrelvir (development code GST-HG171) is a drug for the treatment of COVID-19. It has broad-spectrum anti-SARS-CoV-2 activity against different variants (including WT, β, δ, and omicron).
In combination with ritonavir, it was approved for use in China in 2023.
References
COVID-19 drug development
Nitriles
Pyrrolidones
SARS-CoV-2 main protease inhibitors
Trifluoromethyl compounds
Carboxamides
Cyclopropyl compounds
Spiro compounds
Tert-butyl compounds | Atilotrelvir | [
"Chemistry"
] | 135 | [
"Drug discovery",
"Functional groups",
"Organic compounds",
"COVID-19 drug development",
"Nitriles",
"Spiro compounds"
] |
78,789,895 | https://en.wikipedia.org/wiki/2025%20in%20architecture | This article covers 2025 in architecture.
Events
January 7 to present - Several architecturally significant buildings were destroyed in the January 2025 Southern California wildfires.
Buildings and structures
Australia
Powerhouse Parramatta, expected in Sydney
Cambodia
Techno International Airport, expected in Phnom Penh
Japan
Naoshima New Museum of Art, expected in Naoshima
Tottori Prefectural Museum, in Tottori: expected to open on 30 March 2025
Netherlands
Fenix Museum, in Rotterdam: expected to open on 16 May 2025
United States
Doris Duke Theatre, in Becket, Massachusetts: expected to reopen after renovations on 9 July 2025
Universal Epic Universe, in Orlando, Florida: expected to open on 22 May 2025
Awards
AIA Gold Medal – Deborah Berke
Exhibitions
Deaths
January 3 - Hiroshi Hara, 88, Japanese architect (Kyōto Station, Umeda Sky Building, Sapporo Dome) (born 1936
References
See also
Timeline of architecture
:Category:Buildings and structures destroyed by the January 2025 Southern California wildfires
2025 architecture
2025-related lists
21st-century architecture | 2025 in architecture | [
"Engineering"
] | 217 | [
"Architecture stubs",
"Architecture"
] |
78,789,985 | https://en.wikipedia.org/wiki/Carroll%20B.%20Williams%20Jr. | Carroll Burns Williams Jr. (September 24, 1929 – March 1, 2024) was an American research forester and entomologist. He was the first African American scientist hired by the United States Forest Service and the first African American to receive a Ph.D. in forestry and entomology. He produced pioneering research on pesticide use in forests and insect-host relationships, including bark beetles, spruce budworms and other invasive species.
Early life
Williams was born in St. Louis, Missouri in 1921. His father was an African American pharmacist and his mother was a physical education teacher of African American, Osage, and Kiowa heritage. During the Great Depression, Williams lived with his mother’s family in Leavenworth, Kansas. He often stayed with extended family, including uncles who had been Buffalo Soldiers. Later, Williams moved to Chicago, Illinois and attended Lindblom High School. He was initially denied admission to the University of Michigan School of Natural Resources, but appealed the decision after he discovered that a white student with lower grades had been accepted. He was subsequently admitted “with apologies.”
Williams' freshman year coincided with the start to the Korean War. He enlisted in the United States Marine Corps, becoming one of the first African American soldiers to serve in an integrated unit. He was promoted to the rank of Staff Sergeant and fought in the Battle for Outpost Vegas.
Education
Williams was the first African American to receive a Ph.D. in forestry and entomology. He returned to University of Michigan using the G.I. Bill. In 1955, Williams completed his bachelors of science in forestry from University of Michigan, becoming the first African American student to graduate from Michigan’s School of Natural Resources. He earned a Master of Forestry in 1957 and Ph.D. in forestry with an emphasis in entomology and statistics in 1963 from Michigan. At college, Williams was elected to the student council and was a member of the Society of Les Voyageurs.
Career and research
Williams worked as a forester and entomologist at various Forest Service research stations across the Pacific Northwest and Northeast. He is considered to have been an expert in large-scale chemical control operations and pilot tests for combatting pests. He specialized in pest management, insecticide field tests, and chemical control operations. His studies concerning spruce budworms contributed to the Environmental Protection Agency's approval of alternatives to DDT against the pest.
In 1968, Williams was assigned to New Haven, Connecticut to study the invasive bark beetle. While in New Haven, he joined the faculty of the Yale School of Forestry, serving as the first African American in the environmental sciences department.
In 1972, Williams moved to the Berkeley, California to design and conduct field tests of experimental insecticides against forest-defoliating insects. In 1975, the Forest Service named him a Pioneering Scientist. In 1985, he published a comprehensive guide to testing insecticides on coniferous forest pests. He went on to lead projects on integrated pest management principles in forest systems until his retirement from the Forest Service in 1988.
After leaving the Forest Service, Williams was appointed a senior lecturer in the Department of Forestry and Range Management at University of California, Berkeley. He served as the associate dean for Professional Degree Programs in the College of Natural Resources from 1995 to 1998 and led efforts to redevelop the forestry library into a Student Resource Center. He retired from UC Berkeley in 2003.
Community work and activism
Williams was a member of minority recruitment programs at both Yale and UC Berkeley. In 1977, Williams was elected to the School Board of the Berkeley Unified School District. In 1979, he was unanimously elected to School Board President. He served as a member of the National Science Foundation, the Urban League Black Executives Exchange, and as a youth counselor for the NAACP.
Legacy
In 2021, the University of Michigan School for Environment and Sustainability established the Dr. Carroll B. Williams Fund for Black Excellence. The fund is aimed at supporting students who have a degree from a Historically Black College or University.
In 2024, Ensemble Studio Theater commissioned a play about Williams’ career through the EST/Sloan Project Commission.
He was the father of three children, including screenwriter and author Maiya Williams.
References
1929 births
2024 deaths
Foresters
American scientists
Environmental scientists
20th-century African-American scientists
20th-century African-American educators
African-American environmentalists
21st-century African-American scientists
21st-century African-American educators
People from Berkeley, California
People from New Haven, Connecticut
People from Leavenworth, Kansas | Carroll B. Williams Jr. | [
"Environmental_science"
] | 917 | [
"American environmental scientists",
"Environmental scientists"
] |
78,790,007 | https://en.wikipedia.org/wiki/Great%20Comet%20of%20390 | The Great Comet of 390 AD, also known as C/390 Q1 by its modern designation, was a comet that appeared very bright in the night sky. It was recorded prominently in ancient Chinese and Korean texts, particularly the Chén Shū.
Discovery and observations
No surviving contemporary records of the comet are known. The earliest mention of the comet is found in the Chén Shū text, which was compiled by Chinese astronomer, Li Chunfeng, in 635 AD. The exact date of discovery isn't known, but according to the Chén Shū, the comet was probably discovered as a "sparkling star" that appeared between the stars Castor and Pollux, which based on Ichiro Hasegawa's orbital reconstructions in 1979, it is most likely the early morning of 22 August 390. The Koreans might have also seen the comet at the same time as the Chinese, but they weren't specific on the date of observations.
According to Chinese sources, the comet then moved towards the constellations Lynx and Ursa Major on 28 August. It reached its peak magnitude of –1.0 on 8 September 390, now sporting a tail about 70–100 degrees in length. It was last seen by Chinese astronomers on 17 September 390.
References
External links
Non-periodic comets
Great comets | Great Comet of 390 | [
"Astronomy"
] | 258 | [
"Astronomy stubs",
"Comet stubs"
] |
78,790,313 | https://en.wikipedia.org/wiki/WY%20Velorum | WY Velorum, also known as HD 81137, is a binary system between a variable red supergiant (RSG) and a blue giant companion in the constellation of Vela. It is located approximately distant. Its apparent magnitude slowly varies over the course of years between 8.84 and 10.22. As such, it has been described as an irregular variable, though a rough 550-day period and a more uncertain 370-day period have been detected. The primary star is among the largest stars discovered to date, with an estimated radius of 1,157 (). If it replaced the Sun, its surface would reach past Jupiter's orbit (5.20 AU).
Physical properties
Early publications in 1928 and 1939 classified the star as a possible R Coronae Borealis variable. Later authors were split on whether it was a symbiotic star or a VV Cephei-type star. The two differ in that the former consists of a red giant and a white dwarf or neutron star, while the latter is usually composed of a K- or M-type RSG and a massive early B-type star. The latter was confirmed to be the case in a 1988 paper, and the companion was identified as a giant star with the spectral type B2. This study also presented the absolute magnitudes of the two stars, −4.8 for the primary and −1.7 for the secondary, albeit this has been calculated using a distance of 1400 pc, smaller than modern estimates. With an updated value of 1900 pc, its KS band absolute magnitude is gauged at −11.3. No radial velocity variations have been detected, so the binary likely has a small orbital inclination.
Spectrum
The star has a peculiar spectrum, as indicated by the "pe" suffix in the spectral type (the "p" stands for peculiar, and the "e" stands for emission lines). It displays various strong emission lines, namely of hydrogen, nitrogen, oxygen, silicon, sulfur, iron, nickel, copper, and possibly chromium, many of them forbidden lines. Among them, the strong [Fe II] (forbidden line of singly ionized iron) emission is particularly unusual and recognizable. However, in the ultraviolet region, as observed by the International Ultraviolet Explorer, it only shows the emission lines for Mg II (Mg+). In this regard, it is similar to the symbiotic star CH Cygni, except that CH Cygni also has neutral oxygen lines.
Excess infrared emission signifies the existence of circumstellar dust at a temperature of . The spectrum does not appear to be reddened.
Historical observations
The star's variability was first discovered by Annie Jump Cannon. Between 1890 and 1901, the brightness gradually increased from magnitude 9.8 to 9.2, but it slowly dimmed since 1902 to reach magnitude 10.1 by May 1922. Additional research on the light curves published in 1947 by Cecilia Payne-Gaposchkin indicate that the fading that began in 1902 halted around 1916, after which the star remained almost constant until 1933, when it began to brighten again.
No discernible changes occurred in the spectrum of the star between 1944 and 1948, but in 1952, the H-α line shifted from a single line to a double line, and previously unseen faint H-β features appeared. In 1956, it was reported that the calcium H and K lines swung from absorption to emission during two consecutive nights. By 1969, the RSG had likely become fainter than it was in the 1940s.
References
Vela (constellation)
081137
M-type supergiants
B-type giants
CD-52 03010
J09215913-5233514
Binary stars
Velorum, WY | WY Velorum | [
"Astronomy"
] | 768 | [
"Vela (constellation)",
"Constellations"
] |
78,790,471 | https://en.wikipedia.org/wiki/USA-440 | USA-440, also known as GPS-III SV07, NAVSTAR 83, RRT-1 or Sally Ride, is a United States navigation satellite which forms part of the Global Positioning System.
The satellite is named after Sally Ride.
The RRT-1 name refers to the Rapid Response Trailblazer program in which the satellite was launched on an accelerated timeline.
Satellite
SV07 is the seventh GPS Block III satellite to launch.
Launch
USA-440 was launched by SpaceX on 16 December 2024 at 7:52pm Eastern, atop a Falcon 9 rocket.
The launch took place from SLC-40 at Cape Canaveral Space Force Station.
References
GPS satellites
USA satellites
SpaceX military payloads
Spacecraft launched in 2024 | USA-440 | [
"Technology"
] | 152 | [
"Global Positioning System",
"GPS satellites"
] |
78,791,500 | https://en.wikipedia.org/wiki/Free%20play | Free play, also known as unstructured play, represents the spontaneous, self-directed activity of young children, undertaken independently of adult or older peer guidance. Unlike structured play, characterized by predetermined rules, objectives, and often adult intervention, free play is intrinsically motivated and lacks specific goals or prescribed outcomes. The child dictates every facet of the experience, from the selection of activities and materials to the duration, style, and overall narrative of their play.
This seemingly simple act of unstructured engagement holds profound implications for a child's holistic development, influencing physical, cognitive, social, emotional, and creative domains. These effects are often underestimated in contemporary society’s increasingly structured environments.
Key elements
Several key elements distinguish true free play from other forms of play, including guided play, where adults structure the environment to facilitate specific learning objectives while still allowing for child-led engagement.
The most crucial aspect is the child’s autonomous initiation and control. Children freely choose their activities, partners (or choose to play alone), and materials. This choice extends to the duration and intensity of the play; a child might engage in a short burst of energetic activity followed by quiet, contemplative play, all dictated by their internal drive and fluctuating interests.
The absence of externally imposed structures, including time constraints, predefined rules, or adult-directed objectives, further underscores the autonomy at the heart of free play. The child’s intrinsic motivations, curiosities, and emerging understanding of the world serve as the sole compass guiding their playful exploration.
Furthermore, free play often involves symbolic representation, where objects or actions take on different meanings, reflecting a child’s developing imagination and narrative abilities. For example, a cardboard box might become a spaceship, a house, or a fort, depending on the child’s evolving fantasy.
Developmental benefits
Physical
The impact of free play on a child’s development is multifaceted as it cultivates both gross and fine motor skills through movement, manipulation of objects, and experimentation with physical capabilities. Children also develop strength, coordination, balance, and dexterity as they climb, jump, run, build, and manipulate toys. This physical activity is often more extensive and vigorous than that observed in structured settings, contributing significantly to overall physical health and well-being.
Cognitive
Beyond physical development, free play significantly enhances cognitive development. It fosters creativity by allowing children to explore different possibilities, experiment with ideas, and develop their own solutions to playful challenges. Problem-solving skills are honed as children encounter obstacles and devise strategies to overcome them. The open-ended nature of free play allows for diverse approaches, encouraging flexible thinking through a growth mindset and the capacity for innovative solutions. This self-directed problem-solving extends beyond the immediate context of the play, building a foundation for critical thinking and adaptability in other areas of life.
Socio-emotional
The social and emotional benefits of free play are equally significant. Children learn to navigate social interactions, negotiating, cooperating, compromising, and resolving conflicts with peers. They develop empathy as they observe and participate in the emotional dynamics of their play interactions. Self-regulation, the ability to manage one’s emotions and impulses, is strengthened as children learn to negotiate disagreements, cope with frustration, and regulate their behavior within the context of play, with a 2021 study by Colliver et al. finding a positive correlation between time spent playing freely as a toddler and self-regulation 2 years later. The capacity for self-expression also flourishes in this unstructured environment, allowing children to express themselves creatively and explore various roles and identities. Building self-confidence and independence are also fostered as children independently initiate, sustain, and conclude their play activities.
Through free play, children gain a sense of agency, discovering their own capabilities and limits, reinforcing their sense of self-efficacy.
The role of the environment
The environment plays a vital role in supporting and nurturing free play. Parents and caregivers act as facilitators, providing appropriate resources and ensuring safety without dictating the play itself. This involves creating a rich and stimulating environment that encourages exploration and creativity.
Providing access to a variety of open-ended materials, such as blocks, art supplies, dress-up clothes, and natural materials, allows children to engage in diverse and imaginative play. The availability of both indoor and outdoor spaces is crucial, each offering unique opportunities for exploration and discovery. Outdoor environments, in particular, provide opportunities for gross motor activity, sensory exploration, and interactions with nature, contributing significantly to a child’s holistic development. Importantly, the environment should promote safety, eliminating potential hazards while fostering a sense of freedom and autonomy.
However, fostering free play isn't simply about providing materials; it's about minimizing interference. Adults should observe, support, and provide occasional guidance when needed, but should avoid directing or controlling the play itself. Resisting the urge to structure the play, teach a specific lesson, or impose a preferred outcome is crucial. Adults should act as facilitators, creating the conditions for free play to thrive, rather than participants who direct its flow. This approach acknowledges the inherent value of the child’s own internal drive and capacity for self-directed learning.
Misconceptions
Despite its significant benefits, free play is often misunderstood or undervalued in modern society. Free play as unproductive or less valuable than structured activities, with many schoolchildren given less free time and fewer physical outlets at school, according to Ginsburg et al. 2007.
Free play is not merely a pastime; it is a fundamental process through which children learn and develop across multiple domains. The seemingly unstructured nature of free play masks the complex cognitive, social, and emotional processes taking place, which are difficult to quantify but essential for a child’s development.
It is also crucial to differentiate free play from idleness or inactivity. Free play is an active process of exploration, experimentation, and self-discovery, far from the passive experience of simply being unoccupied.
Impact beyond childhood
Free play remains a crucial element of healthy early child development. Its significance extends far beyond childhood, laying the groundwork for essential life skills such as creativity, problem-solving, self-regulation, and social competence.
Prioritizing free play in early childhood sets the stage for a more resilient, adaptable, and imaginative adult. By creating environments that support and nurture free play, children are empowered to explore their potential, develop their unique talents, and build the foundations of creativity, problem solving, self-regulation and empathy.
References
Developmental psychology
Cognitive development
Parenting
Psychology of learning
Pedagogy
Learning methods | Free play | [
"Biology"
] | 1,377 | [
"Behavioural sciences",
"Behavior",
"Developmental psychology"
] |
78,793,038 | https://en.wikipedia.org/wiki/Blue%20sun | The Sun may appear blue after volcanic eruptions or major forest fires. This is typically due to scattering by aerosol particles. Normal Rayleigh scattering is caused by particles much smaller than the wavelength of visible light. The scattering which causes the blue sun appearance is due to larger particles whose size is similar to the wavelength of light.
See also
Blue moon – a similar phenomenon affecting the Moon
Green flash – a phenomenon at sunset, when the last edge of the sun may flash green or even blue
References
Atmospheric optical phenomena
Solar phenomena | Blue sun | [
"Physics"
] | 104 | [
"Physical phenomena",
"Earth phenomena",
"Optical phenomena",
"Solar phenomena",
"Stellar phenomena",
"Atmospheric optical phenomena"
] |
78,794,395 | https://en.wikipedia.org/wiki/C/1899%20E1%20%28Swift%29 | Comet Swift, also known as C/1899 E1 from its modern nomenclature, is a hyperbolic comet that became visible to the naked eye in early 1899. It is one of 13 comets discovered by American astronomer, Lewis A. Swift.
References
External links
Non-periodic comets
Hyperbolic comets | C/1899 E1 (Swift) | [
"Astronomy"
] | 60 | [
"Astronomy stubs",
"Comet stubs"
] |
78,794,800 | https://en.wikipedia.org/wiki/Reduction%20of%20working%20hours%20in%20France | The reduction of working hours is a general trend towards a reduction in annual working time in Europe and North America from the middle of the 19th century.
The concept of working time really appeared with modern wage labor and large-scale industry. As factory work replaced crafts or homework, working time became visible and could be regulated by law. Despite the diversity of situations, there was a general trend towards reducing annual working time in Europe and North America from the middle of the 19th century.
Chronology
In 1841 a Law relating to the labour of children employed in factories, plants and workshops limited the working time of children, from twelve to sixteen years old, to 12 hours per day, and to 8 hours per day from eight to twelve years old.
Decree of 2 March 1848 limited the working day for adults to ten hours in Paris and eleven in the provinces.
Decree of 9 September 1848, revoked the previous one, and set the maximum daily duration at twelve hours.
Law of May 19, 1874 limiting the working time of children under twelve years of age to 6 hours per day in sectors authorized to employ them.
Law of 1892 limiting the working time of women to 11 hours per day, as well as of children from sixteen to eighteen years of age.
Law of March 30, 1900 (publicized on September 30), known as the "Millerand law", limiting the working day to eleven hours from April 1, 1900 until April 1, 1902, then to ten and a half hours until April 1, 1904; and setting the progressive application over a period of four years.
Law of April 23, 1919 establishing the forty-eight-hour week and the eight-hour day.
1936 laws establishing the forty-hour week and paid holidays by the Popular Front.
1982 order establishing the thirty-nine hour week under Mitterrand.
Laws of 1992 and 1993 encouraging the reduction of working hours and the development of part-time work.
Interprofessional agreements of 1995 organizing the distribution of working time over the year.
References
Social history
Related articles
Working time
Lump of labour fallacy
35-hour workweek
Economy of France
Universal inheritance
Job guarantee
Labour economics
Labor
Human resource management
Working time
Labour law
Business law
Human development
Unemployment
Labour movement
Labor relations | Reduction of working hours in France | [
"Biology"
] | 444 | [
"Behavioural sciences",
"Behavior",
"Human development"
] |
78,795,753 | https://en.wikipedia.org/wiki/Louisiana%20Fishing%20Enhancement%20Act | The Louisiana Fishing Enhancement Act (1986-LA R.S. 56:639.6) is a State of Louisiana law that also established the Louisiana Artificial Reef Development Council (Artificial Reef Council). This laid the foundation for the Louisiana artificial reefs program (LARP), that provides policy and procedures, as well as oversight of the Louisiana Department of Wildlife and Fisheries, for the development and implementation of artificial reefs. The Louisiana Artificial Reef Trust Fund was also created. To fund is intended to support artificial reef, especially the Louisiana Rigs-to-Reefs program
History
The Louisiana Fishing Enhancement Act was based on the National Fishing Enhancement Act of 1984 (Public Law 98-623, Title II) and the National artificial reef plan (33 USC 2103) that was amended in 2007 and sponsored by the Atlantic States Marine Fisheries Commission (ASMFC) and Gulf States Marine Fisheries Commission (GSMFC). The Bureau of Safety and Environmental Enforcement (BSEE) is the lead agency for the Rigs-to-Reef (R2R) program.
The Louisiana Fishing Enhancement Act (1986) led to the adoption of the Artificial Reef Plan in 1987 that included the Louisiana Inshore and Nearshore Artificial Reef Plan. Louisiana was the first state to create an artificial reef program. The gulf coast states of Alabama, Florida, Mississippi, and Texas have Rigs-to-Reef programs. Other states like California also have Rigs-to-reef programs.
Rigs-to-Reefs
Louisiana has become the largest rigs-to-reef program in the world and in 1999 created the world's largest artificial reef in the area of the Freeport sulfur mine near Grand Isle, Louisiana.
Louisiana Artificial Reef Trust Fund
The Louisiana Artificial Reef Trust Fund (Artificial Reef Development Fund by Louisiana Revised Statutes Tit. 56, § 639.8), created with the Louisiana Fishing Enhancement Act, and in accordance to section 10 of the Rivers and Harbors Act of 1899, section 404 of the Federal Water Pollution Control Act, section 4(e) of the Outer Continental Shelf Lands Act, National Fishing Enhancement Act of 1984 (Public Law 98-623) sections 204–207, enacted November 8, 1984, which allows funding of artificial reefs, specifically rigs-to-reefs, with a goal of enhancing habitat and diversity of fishery resources and recreational and commercial fishing opportunities, managing and monitoring inshore, nearshore, offshore, and deepwater artificial reef sites.
Governor Bobby Jindal began using Artificial Reef Funds (sweeping of funds), for coastal protection and restoration, into the general operating budget to balance the Louisiana budget. The Louisiana Wildlife Federation considered filing a suit to stop this.
References
Artificial reefs
Marine architecture
Fish conservation
Fisheries law
Louisiana statutes | Louisiana Fishing Enhancement Act | [
"Engineering"
] | 552 | [
"Marine architecture",
"Architecture"
] |
78,796,442 | https://en.wikipedia.org/wiki/2MASS%20J08090250-4858172 | 2MASS J08090250-4858172 (also called NGC 2547–ID8) is a star in the cluster NGC 2547. In 2014 it was reported that the star had brightened in the infrared. This was interpreted as a collision between planetesimals. It is not the first time such a collision was inferred from infrared excess, with likely the first being BD+20 307, but ID8 was one of the first with the event being observed in real time. Later it became clear that two impacts occurred, one in late 2012 and another in early 2014.
In 2007 ID8 was discovered as a member of NGC 2547 and having infrared excess with Spitzer. At the time the excess was interpreted as either a transitional disk or a collision between planetesimals. In 2012 it was discovered that ID8 and HD 23514, both identified as extreme debris disks (EDD), are variable in 24 μm. EDDs are disks that are extreme bright at this wavelength and make up around 1% of all debris disks. This variation was interpreted as a possible major collision, or a few major collisions. This is opposed to debris produced in a collisional cascades in most debris disks. ID8 was variable in 24 μm between 2004 and 2007, showing both brightening and fading. Observations in 2007 with the Spitzer spectrograph showed ~98% amorphous grains and ~2% crystalline grains. The system interpreted to produce amorphous sub-micron-sized dust, originating in collisions. The similarity of the spectrum and the spectrum of BD+20 307 was noted. Follow-up observations were carried out with Spitzer IRAC (3.6 and 4.5 μm) and ground-based telescopes in 2012 and 2013. The object brightened in the infrared from 2012 to 2013. After that it decayed in brightness in 2013. At the same time the brightness remained stable in the optical. This was interpreted as a new collision between two bodies before 2013. Periodic variations in the 2013 IRAC light curve was interpreted as dust orbiting at around 0.33 astronomical units (AU).
Additional Spitzer IRAC observations showed a more complex picture. After 2013 the infrared flux increased again, until it declined rapidly in 2015. In 2016/2017 the system brightened again in the infrared, but more slowly. This was interpreted as two impacts, one in late 2012 and a second in early 2014. Short-term variations helped to determine the distance from the star for both events. The 2012 impact event occurred at 0.43 AU and involved two bodies with a size of ≥100 km. The 2014 impact event occurred at 0.24 AU, with the fragments being dominated by boulders with very little vapor condensates. As the cloud spread out, it became transparent to star light, which rapidly removed small grains from the dust cloud, explaining the sharp decline in 2015. It was suggested that the first event was a grazing or hit-and-run collision. It has been shown that fragments from such collisions return later and can impact an object a second time.
Simulations of giant impacts were done to re-create the short-term variability of ID8. As the material orbits the star it will pass trough the collision point and the anticollision line. At these locations all the dust must pass trough a relative narrow region, reducing the size of the dust cloud. This decreases the brightness of the dust cloud. This periodic movement into and out of these locations is what causes short-term variability. The simulations have shown that head-on collisions release material perpendicular to the impact direction and grazing impacts release material parallel to the impact direction. In between head-on and grazing, material is launched in all directions. The simulations did show that the orientation of the impact can cause the material to be spread more widely at the collision point, reducing the short-term variability.
Gallery
See also
List of extrasolar planetary collisions
References
Circumstellar disks
Impact events
G-type main-sequence stars
Vela (constellation)
2MASS objects
Astronomical objects discovered in 2007 | 2MASS J08090250-4858172 | [
"Astronomy"
] | 832 | [
"Vela (constellation)",
"Astronomical events",
"Impact events",
"Constellations"
] |
78,796,582 | https://en.wikipedia.org/wiki/NGC%202692 | NGC 2692 is a spiral galaxy located around 188 million light-years away in the constellation Ursa Major. It was discovered on March 17, 1790, by astronomer William Herschel, and it has a diameter around 46,000 light-years. NGC 2692 is not known to have lots of star-formation, and it is not known to have an active galactic nucleus.
References
External links
Spiral galaxies
NGC objects
Discoveries by William Herschel
Astronomical objects discovered in 1790
Ursa Major | NGC 2692 | [
"Astronomy"
] | 98 | [
"Ursa Major",
"Constellations"
] |
78,796,818 | https://en.wikipedia.org/wiki/Allisartan%20isoproxil | Allisartan isoproxil is an antihypertensive pharmaceutical drug. It belongs to the angiotensin II receptor blocker class of drugs. It is an esterified prodrug, and its metabolism results in the formation of a single metabolite, losartan carboxylic acid (EXP3174), an oxidized form of losartan.
In China, allisartan isoproxil was approved by the Chinese Food and Drug Administration for the treatment of hypertension in 2012, and introduced to the market in 2013.
References
Angiotensin II receptor antagonists
Biphenyls
Butyl compounds
Chloroarenes
Imidazoles
Tetrazoles
Carbonate esters
Esters
Isopropyl compounds
Prodrugs | Allisartan isoproxil | [
"Chemistry"
] | 166 | [
"Esters",
"Functional groups",
"Prodrugs",
"Organic compounds",
"Chemicals in medicine"
] |
78,797,015 | https://en.wikipedia.org/wiki/Chloroatranorin | Chloroatranorin is a chemical compound with the molecular formula . It is a secondary metabolite produced by a variety of lichens and is a member of the depside class of compounds. It was first isolated from the oakmoss Evernia prunastri and characterized in 1934. It is the most common chlorine-containing depside in lichens, and has been identified in dozens of lichen species.
It is a chlorinated derivative of atranorin and the two are frequently found together in the same source. Ramault and colleagues described an improved method to separate the two compounds using thin-layer chromatography.
Properties
Chloroatranorin is a member of the class of chemical compounds called depsides. Its IUPAC name is (3-hydroxy-4-methoxycarbonyl-2,5-dimethylphenyl) 5-chloro-3-formyl-2,4-dihydroxy-6-methylbenzoate. The absorbance maxima (λmax) in the ultraviolet spectrum (in methanol solution) are 213, 252, and 282 nm. Its peaks in the infrared spectrum occur at 710, 764, 790, 810, 850, 904, 942, 992, 1030, 1080, 1115, 1160, 1180, 1270, 1285, 1360, 1385, 1408, 1445, 1582, 1650, 3000, and 3500 cm−1. Chloroatranorin's molecular formula is C19H17ClO8; it has a molecular mass of 408.78 grams per mole. In its purified crystalline form, its melting point is .
Chloroatranorin has been studied for its potential antioxidant, antimicrobial, and anticancer properties.
References
Benzoate esters
Methyl esters
Chloroarenes
Benzaldehydes
Polyphenols
Lichen products
Chlorine-containing natural products | Chloroatranorin | [
"Chemistry"
] | 423 | [
"Natural products",
"Lichen products"
] |
78,797,154 | https://en.wikipedia.org/wiki/Lobaric%20acid | Lobaric acid is a chemical compound with the molecular formula . It has been found in the Antarctic lichen Stereocaulon alpinum and a variety of other lichens. It is a member of the depsidone class of compounds.
The first total synthesis of lobaric acid was reported in 2018 by researchers at the Korea Polar Research Institute and Hanyang University. The synthesis was accomplished in 14 total steps, starting with 4-bromophthalic anhydride. Key steps included an Ullmann aryl ether coupling reaction to connect the two main aromatic rings, followed by a seven-membered lactonization reaction to form the final structure. The synthetic route also allowed access to several derivatives of lobaric acid, including methyllobarin, lobarin, and lobarstin, which showed significant protein tyrosine phosphatase 1B (PTP1B) inhibitory activities.
References
Lichen products
Benzoic acids
Hydroxyarenes
Lactones
Benzodioxepines
Methoxy compounds | Lobaric acid | [
"Chemistry"
] | 216 | [
"Natural products",
"Lichen products"
] |
78,797,966 | https://en.wikipedia.org/wiki/Energy%20blackmail | Energy blackmail is, as defined by the Danish Institute for International Studies (DIIS), a strategic manipulation of energy resources for political or economic gain. It involves primarily oil and natural gas, but also potentially other fuels such as nuclear fuel. Energy blackmail has been used by countries to leverage their energy resources for decades, but the term was popularised after the Russian invasion of Ukraine in 2022 to refer to Russian statements and actions in respect to its relationship with other states and with the European Union (EU).
History
In 1960, OPEC was founded in Baghdad by Iraq, Iran, Kuwait, Saudi Arabia and Venezuela, as a cartel to fix the price of oil on the world market. In 1973 OPEC imposed an embargo on the United States and other countries that supported Israel during the Yom Kippur War, including Netherlands, Portugal, and South Africa.
In 2017, the United States pressured China and other members of the United Nations Security Council to end oil shipments to North Korea in an effort to stop them from continuing their ICBM programme. In 2024 the United States and South Korea established a task force to block North Korea from acquiring oil.
In May 2023, the European Commissioner for Energy Kadri Simson said that Russian President Vladimir Putin's energy blackmail of Europe had failed.
In December 2024, Volodymyr Zelenskyy, the president of Ukraine, accused Robert Fico, the prime minister of Slovakia of opening "a second front" against Ukraine on Putin's orders, in response to Robert Fico's threats to cut off electricity from Slovakia to Ukraine. Robert Fico threatened to cut off energy supplies after Ukraine refused to renew the deal with Russia regarding transport of gas to European Union countries through Ukrainian territory.
In January 2025, the Moldovan government accused Russia of blackmail in regards to gas supplies to the unrecognized breakaway state of Transnistria in its territory, arguing that Russia sought to provoke an energy crisis that would undermine Moldova's pro-Western policies at the time of the 2025 Moldovan parliamentary election later that year. Russia denied the allegations.
See also
2022–2023 Russia–European Union gas dispute
International sanctions against North Korea
1973 oil crisis
Moldova and the Russo-Ukrainian War
References
Blackmail
Blackmail
Foreign relations of Russia | Energy blackmail | [
"Physics"
] | 466 | [
"Energy (physics)",
"Energy",
"Physical quantities"
] |
78,798,008 | https://en.wikipedia.org/wiki/Mackey%20functor | In mathematics, particularly in representation theory and algebraic topology, a Mackey functor is a type of functor that generalizes various constructions in group theory and equivariant homotopy theory. Named after American mathematician George Mackey, these functors were first introduced by German mathematician Andreas Dress in 1971.
Definition
Classical definition
Let be a finite group. A Mackey functor for consists of:
For each subgroup , an abelian group ,
For each pair of subgroups with :
A restriction homomorphism ,
A transfer homomorphism .
These maps must satisfy the following axioms:
Functoriality: For nested subgroups , and .
Conjugation: For any and , there are isomorphisms compatible with restriction and transfer.
Double coset formula: For subgroups , the following identity holds:
.
Modern definition
In modern category theory, a Mackey functor can be defined more elegantly using the language of spans. Let be a disjunctive -category and be an additive -category (-categories are also known as quasi-categories). A Mackey functor is a product-preserving functor where is the -category of correspondences in .
Applications
In equivariant homotopy theory
Mackey functors play an important role in equivariant stable homotopy theory. For a genuine -spectrum , its equivariant homotopy groups form a Mackey functor given by:
where denotes morphisms in the equivariant stable homotopy category.
Cohomology with Mackey functor coefficients
For a pointed G-CW complex and a Mackey functor , one can define equivariant cohomology with coefficients in as:
where is the chain complex of Mackey functors given by stable equivariant homotopy groups of quotient spaces.
References
Further reading
Dieck, T. (1987). Transformation Groups. de Gruyter.
Webb, P. "A Guide to Mackey Functors"
Bouc, S. (1997). "Green Functors and G-sets". Lecture Notes in Mathematics 1671. Springer-Verlag.
Representation theory
Algebraic topology
Functors
Homological algebra | Mackey functor | [
"Mathematics"
] | 452 | [
"Functions and mappings",
"Mathematical structures",
"Mathematical objects",
"Algebraic topology",
"Fields of abstract algebra",
"Topology",
"Mathematical relations",
"Functors",
"Category theory",
"Representation theory",
"Homological algebra"
] |
78,798,205 | https://en.wikipedia.org/wiki/Contra-rotating%20marine%20propellers | Contra-rotating propellers have benefits when providing thrust in marine applications.
Contra-rotating propellers are used on torpedoes due to the natural torque compensation and are also used in some motor boats. The cost of boring out the outer shafts and problems of mounting the inner shaft bearings are not worth pursuing in case of normal ships.
Advantages and disadvantages
Advantages
The propeller-induced heeling moment is compensated (negligible for larger ships).
More power can be transmitted for a given propeller radius.
The propeller efficiency is increased by recovering energy from the tangential (rotational) flow from the leading propeller. Tangential flow does not contribute to thrust, conversion of tangential to axial flow increases both thrust and overall system efficiency.
Disadvantages
The mechanical installation of coaxial contra-rotating shafts is complicated and expensive and requires more maintenance.
The hydrodynamic gains are partially reduced by mechanical losses in shafting.
Applications
Torpedoes such as the Bliss-Leavitt torpedo have commonly used contra-rotating propellers to give the maximum possible speed within a limited diameter as well as counteracting the torque that would otherwise tend to cause the torpedo to rotate around its own longitudinal axis.
Recreational boating also found applications: in 1982 Volvo Penta introduced a contra-rotating boat propeller branded DuoProp. The patented device has been marketed since. After the Volvo Penta patents ran out, Mercury Marine has also produced a corresponding product, MerCruiser Bravo 3.
However, in commercial ships and in traditional machinery arrangement, contra-rotating propellers are rare, due to cost and complexity.
ABB provided an azimuth thruster for ShinNihonkai Ferries in form of the CRP Azipod, claiming efficiency gains from the propeller (about 10% increase) and a simpler hull design. Volvo Penta have launched the IPS (Inboard Performance System), an integrated diesel, transmission and pulling contra-rotating propellers for motor yachts.
At lower power levels, contra-rotating mechanical azimuth thrusters are one possibility, convenient for CRP due to their inherent bevel gear construction. Rolls-Royce and Steerprop have offered CRP versions of their products.
References
Propellers
Marine engineering | Contra-rotating marine propellers | [
"Engineering"
] | 437 | [
"Marine engineering"
] |
78,798,828 | https://en.wikipedia.org/wiki/Bugia%20%28candlestick%29 | A bugia (Latin: scotula, palmatorium, French: bougeoir) or hand-candlestick is liturgical candlestick held beside a Latin Catholic bishop or other prelate.
Description
The bugia is a low, portable candlestick with a long handle, held next to clergy to illuminate books being sung or read from. According to the 1886 Caeremoniale Episcoporum, it was to be made of gold or gilt silver for cardinals and patriarchs and silver for all other prelates, but this distinction was seldom followed. The candle used in the bugia was made of beeswax.
Usage
The bugia is held near and to the right of the book by one of the attendants of the prelate whenever he reads or sings a text from the evangeliary or missal. In the case of the Roman Pontiff, this role is filled by an assistant to the papal throne, but he holds an ordinary wax candle, not a bugia. For any other prelate, this was performed by an acolyte or other cleric. It was generally classified among the pontificalia of a bishop, along with the mitre, crozier, episcopal gloves, and other items.
Until 1905, only bishops and prelates with pontifical privileges could use the bugia at Mass. The motu proprio Inter multiplices issued by Pius X allowed all prelates, even titular protonotaries apostolic, vicars general, and diocesan administrators to use the bugia throughout liturgies. Its use on Good Friday, however, remained forbidden regardless of clerical rank. Also prohibited was its use by the ordinary when he celebrated Mass at the faldstool in the presence of a cardinal. Priests who needed an additional light near the missal on account of darkness were allowed to use a candle, so long as it did not have the form of the bugia. In 1968 its use was restricted to situations where practicality made its use necessary.
Etymology
The Latin word "bugia" (), originates from the city of Bougie, Algeria, a source of candle wax.
See also
Episcopal gloves
Solemn Pontifical Mass
Pontifical Vestments
References
External links
Artworks in metal
Formal insignia
Catholic liturgy
Episcopacy in the Catholic Church
Religious objects
Christian religious objects | Bugia (candlestick) | [
"Physics"
] | 463 | [
"Religious objects",
"Physical objects",
"Matter"
] |
71,425,847 | https://en.wikipedia.org/wiki/Bryophilous%20lichen | A bryophilous lichen is one that grows on a bryophyte – that is, on a moss or liverwort. Those which grow on mosses are known as muscicolous lichens, while those which grow on liverworts are called hepaticolous lichens. Muscicolous derives from the Latin muscus meaning moss, while the suffix colous means "living or growing in or on". Lichens are slow-growing organisms, and so are far more likely to be overgrown by a bryophyte than to overgrow one. However, they are better able to compete if the bryophyte is sickly or decaying and they can be parasitic upon them. Some, rather than overgrowing the bryophyte, instead live among its branches. Bryophilous lichens are particularly common in heathland and arctic or alpine tundra. Because many are small and inconspicuous, they are easy to overlook.
Citations
References
Lichenology | Bryophilous lichen | [
"Biology"
] | 214 | [
"Lichenology"
] |
71,426,398 | https://en.wikipedia.org/wiki/Magnetic%20switchback | Magnetic switchbacks are sudden reversals in the magnetic field of the solar wind. They can also be described as traveling disturbances in the solar wind that caused the magnetic field to bend back on itself. They were first observed by the NASA-ESA mission Ulysses, the first spacecraft to fly over the Sun's poles. NASA's Parker Solar Probe and NASA/ESA Solar Orbiter both observed switchbacks.
Definition
Magnetic (or solar) switchback is a rapid polarity reversals of the radial heliospheric magnetic field. These events have been termed "switchbacks", when referring to the change in magnetic field direction, or "velocity spikes", when referring to the sharp increase in solar wind speed.
The switchbacks generate heat that warms solar corona.
Observations
Helios 1 and 2 spacecraft observed sudden reversals of the Sun's magnetic field in 1970s. Magnetic switchbacks were then observed by the Ulysses in 1995-1996, during the solar minimum, when the spacecraft detected numerous radial magnetic field polarity inversions. Similar structures were then observed by near-Earth heliospheric spacecraft such as Advanced Composition Explorer. Parker Solar Probe (PSP) observed first switchback on November 6, 2018. Similar effects were observed at distances around and below 0.3 AU, 1 AU, and up to 2.9 AU, and, as noted by Fedorov et al, "the question of whether all such observations relate to the same phenomenon is still open."
On 27 September 2020, ESA/NASA Solar Orbiter (SolO) sampled a solar wind stream magnetically connected to a southern hemisphere coronal hole, while it was at 0.98 AU from Sun, and observed a fast solar wind with strong fluctuations of the magnetic field. The structures observed by SolO may effectively stand as the surviving remains of the switchbacks created near Sun and also observed by PSP.
Given the phase of the solar cycle, if PSP was in the southern magnetic hemisphere, the solar wind magnetic field should always have had a magnetic polarity oriented inward toward the Sun. Instead, PSP observed thousands of intervals, ranging in duration from seconds to tens of minutes where the speed of the solar wind flow suddenly jumps and the magnetic field orientation rotates by nearly 180° in the most extreme cases, before returning just as quickly to the original solar wind conditions.
SolO has found compelling clues as to the origin of magnetic switchbacks during its closest pass by the sun on 25 March 2022. Using the data of the Solar Orbiter Daniele Telloni and Gary Zank and their team came to the conclusion that the theory based on Ulysses data is correct, they "proved that switchbacks occur when there is an interaction between a region of open field lines and a region of closed field lines".
Theories
One theory, based on the Ulysses data, suggests that switchbacks are the result of a clash between open and closed magnetic fields. When an open magnetic field line brushes against a closed magnetic loop, they can reconfigure in a process called interchange reconnection – an explosive rearrangement of the magnetic fields that leads to a switchback shape. The open line snaps onto the closed loop, cutting free a hot burst of plasma from the loop, while "gluing" the two fields into a new configuration. That sudden snap throws an S-shaped kink into the open magnetic field line before the loop reseals. The Parker Solar Probe observed its first switchback on November 6, 2018. The observed switchback was close to the developed model.
A second theory agrees on the import of interchange reconnection, but differs on the nature of switchbacks themselves. Instead of viewing switchbacks as a kink in a magnetic field line, the second theory suggests it is the signature of a kind of magnetic structure, called a flux rope.
Another theory suggests that switchbacks form naturally as the solar wind expands into space.
The switchbacks, essentially S-shaped kinks in the magnetic field lines streaming from the Sun, seem to arise from a reconfiguration of open and looped magnetic field lines already in the Sun's atmosphere. When an open magnetic field line encounters a closed magnetic loop they can undergo a process called interchange reconnection. This allows the open magnetic field line to snap into the loop, and allows one side of the formerly closed magnetic loop to connect to solar magnetic field extending outwards into the solar system. This process would create an outward-flowing S-shaped kink in the newly formed open magnetic field line — a shape that tracks with the switchbacks measured by Parker Solar Probe.
Gallery
See also
Magnetic reconnection
Further reading
References
Sun
Solar phenomena | Magnetic switchback | [
"Physics"
] | 949 | [
"Physical phenomena",
"Stellar phenomena",
"Solar phenomena"
] |
71,426,550 | https://en.wikipedia.org/wiki/Lanthanum%28III%29%20iodide | Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula .
Synthesis
Lanthanum(III) iodide can be synthesised by the reaction of lanthanum metal with mercury(II) iodide:
2 La + 3 HgI2 → 2 LaI3 + 3 Hg
It can also be prepared from the elements, that is by the reaction of metallic lanthanum with iodine:
2 La + 3 I2 → 2 LaI3
While lanthanum(III) iodide solutions can be generated by dissolving lanthanum oxide in hydroiodic acid, the product will hydrolyse and form polymeric hydroxy species:
La2O3 + 6 HI → 2 LaI3 + 3 H2O → further reactions
Structure
Lanthanum(III) iodide adopts the same crystal structure as plutonium(III) bromide, with 8-coordinate metal centres arranged in layers. This orthorhombic structure is typical of the triiodides of the lighter lanthanides (La–Nd), whereas heavier lanthanides tend to adopt the hexagonal bismuth(III) iodide structure.
Reactivity and applications
Lanthanum(III) iodide is very soluble in water and is deliquescent. Anhydrous lanthanum(III) iodide reacts with tetrahydrofuran to form a photoluminescent complex, LaI3(THF)4, with an average La–I bond length of 3.16 Å. This complex is a starting material for amide and cyclopentadienyl complexes of lanthanum.
Related compounds
Lanthanum also forms a diiodide, LaI2. It is an electride and is best formulated {LaIII,2I−,e−}, with the electron delocalised in a conduction band. Several other lanthanides form similar compounds, including CeI2, PrI2 and GdI2. Lanthanum diiodide adopts the same tetragonal crystal structure as PrI2.
Lanthanum(III) iodide reacts with lanthanum metal under an argon atmosphere in a tantalum capsule at 1225 K to form the mixed-valence compound La2I5.
Reduction of LaI2 or LaI3 with metallic sodium in an argon atmosphere at 550 °C gives lanthanum monoiodide, LaI, which has a hexagonal crystal structure.
References
Lanthanum compounds
Iodides
Inorganic compounds
Lanthanide halides | Lanthanum(III) iodide | [
"Chemistry"
] | 537 | [
"Inorganic compounds"
] |
71,427,635 | https://en.wikipedia.org/wiki/W40%20IRS%201A%20South | W40 IRS 1A South is a young O-type star in the H II region, Westerhout 40, one of the closest O type stars to the Sun at just over 1,400 light years away. It is the only known O-type star in W40 and is responsible for most of W40's ionisation, and its stellar wind has carved out a 4 pc wide bubble around it, which can be seen in wide field mid-IR images. W40 IRS 1A South is separated from its northern counterpart, W40 IRS 1A North, which is a heavily reddened Herbig Be star, by approximately 2".
Properties
Not much is known about IRS 1A South, given how reddened and extinguished it is (by 10.6 magnitudes, which is why it is so dim despite being such a massive star so close to us, i.e. only 0.0058% of its light reaches us). So far attempts to derive its parameters have used averages from its spectral type of O9.5 (V), and different models have given different parameters. The most recent temperature value for IRS 1A South is 31,500 Kelvin, and the most recent radius value is 7.71 solar radii. Considering these parameters and the Stefan–Boltzmann law derives a luminosity of about 52,500 solar luminosities. Assuming the distance of 436 parsecs, the apparent magnitude of about 15 and the extinction of 10.6 magnitudes, IRS 1A South has an absolute magnitude of -4.25, i.e. it's about 4,300 times brighter than the Sun in the visible wavelength.
References
Serpens
O-type main-sequence stars | W40 IRS 1A South | [
"Astronomy"
] | 352 | [
"Constellations",
"Serpens"
] |
71,427,873 | https://en.wikipedia.org/wiki/Chlorphoxim | Chlorphoxime is an insecticide used as crop protection active ingredient. Chlorphoxime is also a cholinesterase inhibitor and a neurotoxin.
Properties
A study was conducted to investigate the effect of chlorophoxime for the control of fleas in kangaroo rats and hispid cotton rats. Chlorphoxime was found to be effective.
In another study, the efficacy of some insecticides was investigated on certain storage pests. While phoxim, bioresmethrin and fenitrothion showed strong activity against the red-brown rice mealybug, the insecticidal activity of chlorphoxim and permethrin was low.
Production
The synthesis of chlorophoxime is described in the following reaction sequence:
Trade names
A crop protection product containing the active ingredient chlorophoxime is marketed under the trade name Baythion.
Approval
No plant protection products containing chlorophoxime are approved in the European Union or Switzerland.
References
2-Chlorophenyl compounds
Oxime esters
Nitriles
Thiophosphoryl compounds
Ethyl esters | Chlorphoxim | [
"Chemistry"
] | 240 | [
"Nitriles",
"Functional groups",
"Thiophosphoryl compounds"
] |
71,428,073 | https://en.wikipedia.org/wiki/Elementary%20modes | In biochemistry, elementary modes may be considered minimal realizable flow patterns through a biochemical network that can sustain a steady state. This means that elementary modes cannot be decomposed further into simpler pathways. All possible flows through a network can be constructed from linear combinations of the elementary modes.
The set of elementary modes for a given network is unique (up to an arbitrary scaling factor). Given the fundamental nature of elementary modes in relation to uniqueness and non-decomposability, the term 'pathway' can be defined as an elementary mode. Note that the set of elementary modes will change as the set of expressed enzymes change during transitions from one cell state to another. Mathematically, the set of elementary modes is defined as the set of flux vectors that satisfy the steady state condition
where is the stoichiometry matrix, is the vector of rates, the vector of steady state floating (or internal) species and , the vector of system parameters.
An important condition is that the rate of each irreversible reaction must be non-negative,
A more formal definition is given by:
An elementary mode, , is defined as a vector of fluxes, , such that the three conditions listed in the following criteria are satisfied.
The vector must satisfy: , that is: the steady state condition.
For all irreversible reactions: . This means that all flow patterns must use reactions that proceed in their most natural direction. This makes the pathway described by the elementary mode a thermodynamically feasible pathway.
The vector must be elementary. That is, it should not be possible to generate by combining two other vectors that satisfy the first and second requirements using the same set of enzymes that appear as non-zero entries in . In other words, it should not be possible to decompose into two other pathways that can themselves sustain a steady state. This is called elementarity. A more formal test is that the null space of the submatrix of that only involves the reactions of is of dimension one and has no zero entries.
Example
Consider a simple branched pathway with all three steps irreversible. Such a pathway will admit two elementary modes which are indicated in thicked (or red) reaction lines.
Because both and are irreversible, and elementary mode lying on both these reactions is not possible since it would mean one reactions going against its thermodynamic direction. Each mode in this system satisfies the three conditions described above. The first condition is steady state, that is for each mode , it has to be true that .
Algebraically the two modes are given by:
By substituting each of these vectors into , it is easy to show that condition one is satisfied. For condition two we must ensure that all reactions that are irreversible have positive entries in the corresponding elements of the elementary modes. Since all three reactions in the branch are irreversible and all entries in the elementary modes are positive, condition two is satisfied.
Finally, to satisfy condition three, we must ask whether we can decompose the two elementary modes into other paths that can sustain a steady state while using the same non-zero entries in the elementary mode. In this example, it is impossible to decompose the elementary modes any further without disrupting the ability to sustain a steady state. Therefore, with all three conditions satisfied, we can conclude that the two vectors shown above are elementary modes.
All possible flows through a network can be constructed from linear combinations of the elementary modes, that is:
such that the entire space of flows through a network can be described. must be greater than or equal to zero to ensure that irreversible steps aren't inadvertently made to go in the reverse direction. For example, the following is a possible steady-state flow in the branched pathway.
If one of the outflow steps in the simple branched pathway is made reversible, an additional elementary mode becomes available, representing the flow between the two outflow branches. An additional mode emerges because, with only the first two modes, it is impossible to represent a flow between the two branches because the scaling factor, , cannot be negative (which would be required to reverse the flow).
Definition of a Pathway
The Wikipedia page Metabolic pathway defines a pathway as "a metabolic pathway is a linked series of chemical reactions occurring within a cell". This means that any sequence of reactions can be labeled a metabolic pathway. However, as metabolism was being uncovered, groups of reactions were assigned specific labels, such as glycolysis, Krebs Cycle, or Serine biosynthesis. Often the categorization was based on common chemistry or identification of an input and output. For example, serine biosynthesis starts at 3-phosphoglycerate and ends at serine. This is a somewhat ad hoc means for defining pathways, particularly when pathways are dynamic structures, changing as environmental result in changes in gene expression. For example, the Kreb Cycle is often not cyclic as depicted in textbooks. In E. coli and other bacteria, it is only cyclic during aerobic growth on acetate or fatty acids. Instead, under anaerobiosis, its enzymes function as two distinct biosynthetic pathways producing succinyl-CoA and α-ketoglutarate.
It has therefore been proposed to define a pathway as either a single elementary mode or some combination of elementary modes. The added advantage is that the set of elementary modes is unique and non-decomposable to simpler pathways. A single elementary mode can therefore be thought of as an elementary pathway. Note that the set of elementary modes will change as the set of expressed enzymes change during transitions from one cell state to another.
Elementary modes, therefore, provide an unambiguous definition of a pathway.
Comment on Condition Three
Condition three relates to the non-decomposability of an elementary mode and is partly what makes elementary modes interesting. The two other important features as indicated before are pathway uniqueness and thermodynamic plausibility. Decomposition implies that it is possible to represent a mode as a combination of two or more other modes. For example, a mode might be composed from two other modes, and :
If a mode can be decomposed, does it mean that the mode is not an elementary mode? Condition three provides a rule to determine whether a decomposition means that a given mode is an elementary mode or not. If it is only possible to decompose a given mode by introducing enzymes that are not used in the mode, then the mode is elementary. That is, is there more than one way to generate a pathway (i.e., something that can sustain a steady state) with the enzymes currently used in the mode? If so, then the mode is not elementary. To illustrate this subtle condition, consider the pathway shown in below.
This pathway represents a stylized rendition of glycolysis. Step three and six are reversible and correspond to triose phosphate isomerase and glycerol 3-phosphate dehydrogenase, respectively.
The network has four elementary flux modes, which are shown in the figure below.
The elementary flux mode vectors are shown below:
Note that it is possible to have negative entries in the set of elementary modes because they will correspond to the reversible steps. Of interest is the observation that the fourth vector, (where represents the transpose) can be formed from the sum of the first and second vectors. This suggests that the fourth vector is not an elementary mode.
However, this decomposition only works because we have introduced a new enzyme, (triose phosphate isomerase) which is not used in . It is, in fact impossible to decompose into pathways that can sustain a steady state with only the five steps, , used in the elementary mode. We conclude therefore that is an elementary mode.
See also
Computational systems biology
Metabolic control analysis
Metabolic network
Metabolic pathway
Metagenomics
References
Biological engineering
Biomedical engineering
Systems biology
Metabolism
Mathematical and theoretical biology | Elementary modes | [
"Chemistry",
"Mathematics",
"Engineering",
"Biology"
] | 1,628 | [
"Biological engineering",
"Biomedical engineering",
"Mathematical and theoretical biology",
"Applied mathematics",
"Cellular processes",
"Biochemistry",
"Medical technology",
"Metabolism",
"Systems biology"
] |
71,428,969 | https://en.wikipedia.org/wiki/Yuri%20Struchkov | Yuri Timofeevich Struchkov () (28 July 1926, Moscow — 16 August 1995, Charleston, South Carolina) was a Russian and Soviet chemist. He was a prominent scientist in the field X-ray crystallography, a Corresponding Member of the Russian Academy of Sciences (1990) and the vice-president of the International Union of Crystallography (1993-1995). Struchkov was the founder and the first Director of the X-Ray Structural Laboratory of Nesmeyanov Institute of Organoelement Compounds and X-Ray Structural Centre of the Russian Academy of Sciences (RAS). He made important contributions to the fields of chemistry and crystallography of organic, organoelement and coordination compounds. As an author and co-author of more than 1000 papers, published between 1980 and 1990, he became the most widely published scientist of the decade. In 2021, the International Union of Crystallography (IUCr) honored his contributions to the field of small molecule structural crystallography, establishing the Struchkov Prize, which is awarded to the young crystallographers at the regular triennial IUCr International Congress of Crystallography.>
Scientific career
In 1948 Struchkov graduated from the MSU Faculty of Chemistry.
In 1948—1953 he was a working on his Ph.D. thesis under the supervision of professor A.I.Kitaigorodski.
In 1950 he joined the staff of the Zelinsky Institute of Organic Chemistry (IOCh).
In 1953 he defended the PhD thesis X-Ray structural study of two addition products of metal salts to unsaturated compounds.
In 1954—1995 he worked in the Nesmeyanov Institute of Organoelement Compounds (INEOS):
in the laboratory headed by A.I.Kitaigorodski (1954-1973)
in the diffraction studies group (1973-1977)
in the new Laboratory of the X-Ray Structure Analysis (LXRSA) which was founded and headed by him (1977-1995).
In 1989 Struchkov became the Director of the X-Ray Structural Centre of RAS, which was based on the INEOS LXRSA.
In 1990 he was elected Corresponding Member of RAS and a member of the executive committee of the International Union of Crystallography (IUCr).
At the XVI General Assembly of IUCr in 1993 he became the vice-president of the IUCr (1993-1995).
References
1926 births
1995 deaths
Soviet chemists
20th-century Russian chemists
Crystallographers
Ig Nobel laureates | Yuri Struchkov | [
"Chemistry",
"Materials_science"
] | 535 | [
"Crystallographers",
"Crystallography"
] |
71,429,322 | https://en.wikipedia.org/wiki/List | A list is a set of discrete items of information collected and set forth in some format for utility, entertainment, or other purposes. A list may be memorialized in any number of ways, including existing only in the mind of the list-maker, but lists are frequently written down on paper, or maintained electronically. Lists are "most frequently a tool", and "one does not read but only uses a list: one looks up the relevant information in it, but usually does not need to deal with it as a whole".
Purpose
It has been observed that, with a few exceptions, "the scholarship on lists remains fragmented". David Wallechinsky, a co-author of The Book of Lists, described the attraction of lists as being "because we live in an era of overstimulation, especially in terms of information, and lists help us in organizing what is otherwise overwhelming".
While many lists have practical purposes, such as memorializing needed household items, lists are also created purely for entertainment, such as lists put out by various music venues of the "best bands" or "best songs" of a certain era. Such lists may be based on objective factors such as record sales and awards received, or may be generated entirely from the subjective opinion of the writer of the list. Musicologist David V. Moskowitz notes:
The practice of ordering a list evaluating things so that better items on the list are ahead of less good items is called ranking. Lists created for the purpose of ranking a subset of an indefinite population (such as the top 100 of the thousands of bands that have performed in a given genre) are almost always presented as round numbers. Studies have determined that a list of items falling within a round number has a substantial psychological impact, such that "the difference between items ranked No. 10 and No. 11 feels enormous and significant, even if it's actually quite minimal or unknown". The same list may serve different purposes for different people. A list of currently popular songs may provide the average person with suggestions for music that they may want to sample, but to a record company executive, the same list would indicate trends regarding the kinds of artists to sign to maximize future profits.
Organizing principles
Lists may be organized by a number of different principles. For example, a shopping list or a list of places to visit while vacationing might each be organized by priority (with the most important or most desired items at the top and least important or least desired at the bottom), or by proximity, so that following the list will take the shopper or vacationer on the most efficient route.
A list may also completely lack any principle of organization, if it does not serve a purpose for which such a principle is needed. An unsorted list is one "in which data items are placed in no particular order with respect to their content; the only relationships between data elements consist of the list predecessor and successor relationships". For example, in her book, Seriously... I'm Kidding, comedian Ellen DeGeneres provides a list of acknowledgements, notes her difficulty in determining how to order the list, and ultimately writes: "This list is in no particular order. Just because someone is first doesn't mean they're the most important. It doesn't mean they're not the most important either". A list that is sorted by some principle may be said to be following a ranking or sequence.
Items on a list are often delineated by bullet points or a numbering scheme.
Kinds of lists
Kinds of lists used in everyday life include:
Shopping list: a list of items needed to be purchased by a shopper, such as a list of groceries to be purchased on the next visit to the grocery store (a grocery list)
To-do list or Task list: a list or "backlog" of pending tasks
Checklist: a type of job aid used in repetitive tasks to reduce failure by compensating for potential limits of human memory and attention
Roster: a list of people scheduled to participate in a task, such as employees of a company, or, more specifically, professional athletes set to participate in a specific sporting event
Wish list, an itemization of goods or services that a person or organization desires
Many highly specialized kinds of lists also exist. For example, a table of contents is a list of the chapters or other features of a written work, usually at the beginning of that work, and an index is a list of concepts or terms found in such a work, usually at the end of the work, and usually indicating where in the work the concepts or terms can be found. A track list is a list of songs on an album, and set list is a list of songs that a band will regularly play in concerts during a tour. A word list is a list of the lexicon of a language (generally sorted by frequency of occurrence either by levels or as a ranked list) within some given text corpus, serving the purpose of vocabulary acquisition.
Many connoisseurs or experts in particular areas will assemble "best of" lists containing things that are considered the best examples within that area. Where such lists are open to a wide array of subjective considerations, such as a list of best poems, best songs, or best athletes in a particular sport, experts with differing opinions may engage in lengthy debates over which items belong on the list, and in which order.
Task lists
A task list (also called a to-do list or "things-to-do") is a list of tasks to be completed, such as chores or steps toward completing a project. It is an inventory tool which serves as an alternative or supplement to memory. Writer Julie Morgenstern suggests "do's and don'ts" of time management that include mapping out everything that is important, by making a task list. Task lists are also business management, project management, and software development, and may involve more than one list.
When one of the items on a task list is accomplished, the task is checked or crossed off. The traditional method is to write these on a piece of paper with a pen or pencil, usually on a note pad or clip-board. Task lists can also have the form of paper or software checklists. Numerous digital equivalents are now available, including personal information management (PIM) applications and most PDAs. There are also several web-based task list applications, many of which are free.
Task list organization
Task lists are often diarized and tiered. The simplest tiered system includes a general to-do list (or task-holding file) to record all the tasks the person needs to accomplish and a daily to-do list which is created each day by transferring tasks from the general to-do list. An alternative is to create a "not-to-do list", to avoid unnecessary tasks.
Task lists are often prioritized in the following ways.
A daily list of things to do, numbered in the order of their importance and done in that order one at a time as daily time allows, is attributed to consultant Ivy Lee (1877–1934) as the most profitable advice received by Charles M. Schwab (1862–1939), president of the Bethlehem Steel Corporation.
An early advocate of "ABC" prioritization was Alan Lakein, in 1973. In his system "A" items were the most important ("A-1" the most important within that group), "B" next most important, "C" least important.
A particular method of applying the ABC method assigns "A" to tasks to be done within a day, "B" a week, and "C" a month.
To prioritize a daily task list, one either records the tasks in the order of highest priority, or assigns them a number after they are listed ("1" for highest priority, "2" for second highest priority, etc.) which indicates in which order to execute the tasks. The latter method is generally faster, allowing the tasks to be recorded more quickly.
Another way of prioritizing compulsory tasks (group A) is to put the most unpleasant one first. When it is done, the rest of the list feels easier. Groups B and C can benefit from the same idea, but instead of doing the first task (which is the most unpleasant) right away, it gives motivation to do other tasks from the list to avoid the first one.
A completely different approach which argues against prioritizing altogether was put forward by British author Mark Forster in his book "Do It Tomorrow and Other Secrets of Time Management". This is based on the idea of operating "closed" to-do lists, instead of the traditional "open" to-do list. He argues that the traditional never-ending to-do lists virtually guarantees that some of your work will be left undone. This approach advocates getting all your work done, every day, and if you are unable to achieve it, that helps you diagnose where you are going wrong and what needs to change.
Various writers have stressed potential difficulties with to-do lists such as the following.
Management of the list can take over from implementing it. This could be caused by procrastination by prolonging the planning activity. This is akin to analysis paralysis. As with any activity, there is a point of diminishing returns.
To remain flexible, a task system must allow for disaster. A company must be ready for a disaster. Even if it is a small disaster, if no one made time for this situation, it can metastasize, potentially causing damage to the company.
To avoid getting stuck in a wasteful pattern, the task system should also include regular (monthly, semi-annual, and annual) planning and system-evaluation sessions, to weed out inefficiencies and ensure the user is headed in the direction he or she truly desires.
If some time is not regularly spent on achieving long-range goals, the individual may get stuck in a perpetual holding pattern on short-term plans, like staying at a particular job much longer than originally planned.
See also
A-list
Blacklist/Whitelist
The Book of Lists
Difference list
The Infinity of Lists (2009) by Umberto Eco, on the topic of lists
Life list
Linked list
List (abstract data type), in computer science
List comprehension
List of lists of lists
Outline (list)
Self-organizing list
Short list
Wait list
Word list
References
Main topic articles
Information management | List | [
"Technology"
] | 2,127 | [
"Information systems",
"Information management"
] |
71,431,971 | https://en.wikipedia.org/wiki/Hugging%20Face | Hugging Face, Inc. is an American company incorporated under the Delaware General Corporation Law and based in New York City that develops computation tools for building applications using machine learning. It is most notable for its transformers library built for natural language processing applications and its platform that allows users to share machine learning models and datasets and showcase their work.
History
The company was founded in 2016 by French entrepreneurs Clément Delangue, Julien Chaumond, and Thomas Wolf in New York City, originally as a company that developed a chatbot app targeted at teenagers. The company was named after the emoji. After open sourcing the model behind the chatbot, the company pivoted to focus on being a platform for machine learning.
In March 2021, Hugging Face raised US$40 million in a Series B funding round.
On April 28, 2021, the company launched the BigScience Research Workshop in collaboration with several other research groups to release an open large language model. In 2022, the workshop concluded with the announcement of BLOOM, a multilingual large language model with 176 billion parameters.
In December 2022, the company acquired Gradio, an open source library built for developing machine learning applications in Python.
On May 5, 2022, the company announced its Series C funding round led by Coatue and Sequoia. The company received a $2 billion valuation.
In February 2023, the company announced partnership with Amazon Web Services (AWS) which would allow Hugging Face's products available to AWS customers to use them as the building blocks for their custom applications. The company also said the next generation of BLOOM will be run on Trainium, a proprietary machine learning chip created by AWS.
In August 2023, the company announced that it raised $235 million in a Series D funding, at a $4.5 billion valuation. The funding was led by Salesforce, and notable participation came from Google, Amazon, Nvidia, AMD, Intel, IBM, and Qualcomm.
In June 2024, the company announced, along with Meta and Scaleway, their launch of a new AI accelerator program for European startups. This initiative aims to help startups integrate open foundation models into their products, accelerating the EU AI ecosystem. The program, based at STATION F in Paris, will run from September 2024 to February 2025. Selected startups will receive mentoring, access to AI models and tools, and Scaleway’s computing power.
On September 23, 2024, to further the International Decade of Indigenous Languages, Hugging Face teamed up with Meta and UNESCO to launch a new online language translator built on Meta's No Language Left Behind open-source AI model, enabling free text translation across 200 languages, including many low-resource languages.
Services and technologies
Transformers Library
The Transformers library is a Python package that contains open-source implementations of transformer models for text, image, and audio tasks. It is compatible with the PyTorch, TensorFlow and JAX deep learning libraries and includes implementations of notable models like BERT and GPT-2. The library was originally called "pytorch-pretrained-bert" which was then renamed to "pytorch-transformers" and finally "transformers."
A JavaScript version (transformers.js) has also been developed, allowing models to be run directly in the browser.
Hugging Face Hub
The Hugging Face Hub is a platform (centralized web service) for hosting:
Git-based code repositories, including discussions and pull requests for projects.
models, also with Git-based version control;
datasets, mainly in text, images, and audio;
web applications ("spaces" and "widgets"), intended for small-scale demos of machine learning applications.
There are numerous pre-trained models that support common tasks in different modalities, such as:
Natural Language Processing: text classification, named entity recognition, question answering, language modeling, summarization, translation, multiple choice, and text generation.
Computer Vision: image classification, object detection, and segmentation.
Audio: automatic speech recognition and audio classification.
Other libraries
In addition to Transformers and the Hugging Face Hub, the Hugging Face ecosystem contains libraries for other tasks, such as dataset processing ("Datasets"), model evaluation ("Evaluate"), and machine learning demos ("Gradio").
Safetensors
The safetensors format was developed around 2021 to solve problems with using Python's pickle format (that was then used in PyTorch). It was designed for saving and loading tensors. Compared to pickle format, it allows lazy loading, and avoids security problems. After a security audit, it became the default format in 2023.
See also
OpenAI
Station F
Kaggle
References
External links
Machine learning
Open-source artificial intelligence
Privately held companies based in New York City
American companies established in 2016
2016 establishments in New York City | Hugging Face | [
"Engineering"
] | 1,009 | [
"Artificial intelligence engineering",
"Machine learning"
] |
71,432,883 | https://en.wikipedia.org/wiki/Thulium%28II%29%20fluoride | Thulium(II) fluoride is one of the fluoride salts of the lanthanide metal thulium, with the chemical compound of TmF2. It can react with zirconium tetrafluoride at 900 °C to form TmZrF6, which has a hexagonal structure.
In addition, low-temperature Mössbauer spectroscopy and some theoretical studies of thulium(II) fluoride have also been reported.
References
Thulium compounds
Fluorides
Fluorite crystal structure
Lanthanide halides | Thulium(II) fluoride | [
"Chemistry"
] | 118 | [
"Fluorides",
"Salts"
] |
71,432,937 | https://en.wikipedia.org/wiki/Ruthenium%28III%29%20fluoride | Ruthenium(III) fluoride is a fluoride of ruthenium, with the chemical formula of RuF3.
Preparation
Ruthenium(III) fluoride can be obtained from the reduction of ruthenium(V) fluoride by iodine at 250 °C:
5 RuF5 + I2 -> 5 RuF3 + 2 IF5
Properties
Ruthenium(III) fluoride is a dark brown solid that is insoluble in water. It has a space group of Rc (No. 167).
References
Fluorides
Ruthenium(III) compounds | Ruthenium(III) fluoride | [
"Chemistry"
] | 128 | [
"Salts",
"Fluorides",
"Inorganic compounds",
"Inorganic compound stubs"
] |
71,433,131 | https://en.wikipedia.org/wiki/Abdulrahman%20Obaid%20Al-Youbi | Abdulrahman Obaid Al-Youbi (; born 1958) was the president of King Abdulaziz University from June 2016 to October 2022.
Biography
Al-Youbi received his bachelor’s and master’s degree in chemistry from King Abdulaziz University. He attended the University of Essex on a scholarship, where he received his PhD in physical chemistry in 1986.
Before being appointed as president of King Abdulaziz University in 2016, he served as vice president. He was a consultant at the Ministry of Higher Education, and was dean and vice-dean of the faculty of science, at King Abdulaziz University.
References
1958 births
Living people
Saudi Arabian chemists
King Abdulaziz University alumni
Academic staff of King Abdulaziz University
Alumni of the University of Essex
Heads of universities and colleges in Saudi Arabia
Physical chemists | Abdulrahman Obaid Al-Youbi | [
"Chemistry"
] | 169 | [
"Physical chemists"
] |
71,433,745 | https://en.wikipedia.org/wiki/Europium%28III%29%20arsenate | Europium(III) arsenate is an arsenate salt of europium, with the chemical formula of EuAsO4. It has good thermal stability, with its pKsp,c of 22.53±0.03. It is a colorless crystal with a xenotime structure.
Preparation
Europium(III) arsenate can be prepared by reacting sodium arsenate (Na3AsO4) in a europium(III) chloride (EuCl3) solution:
Na3AsO4 + EuCl3 → 3 NaCl + EuAsO4↓
Reacting europium(III) oxide (Eu2O3) with arsenic pentoxide (As2O5) can also obtain europium(III) arsenate.
Eu2O3 + As2O5 → 2EuAsO4
References
Europium(III) compounds
Arsenates | Europium(III) arsenate | [
"Chemistry"
] | 192 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
71,434,006 | https://en.wikipedia.org/wiki/The%20Most%20Hated%20Man%20on%20the%20Internet | The Most Hated Man on the Internet is a 2022 American three-part Netflix docuseries that covers the story of Hunter Moore and his website Is Anyone Up?, a pornographic site based on stolen and hacked photos, and the struggle to take the website down. It focuses on the story of Charlotte Laws as she tries to remove her daughter's nude photos from the website.
Overview
The Most Hated Man on the Internet follows anti-revenge porn activists in their efforts to take down the website IsAnyoneUp.com. Created by Hunter Moore, the website was built so anyone can post a picture of anyone and connect it to their social media accounts. Charlotte Laws started a campaign to try to take it down after her daughter's nude photos were shared on the website.
The documentary is separated into three episodes. It is directed by Rob Miller, an employee of Netflix. The three episodes are made up of interviews of the main roles in the site except Hunter Moore. Hunter originally was willing to be featured and interviewed for the documentary but later declined for unknown reasons.
Reception
The Most Hated Man on the Internet received positive reviews. On the review aggregator website Rotten Tomatoes, the series has an approval rating of 86%, based on 14 reviews, with an average rating of 6.1/10. The website's consensus reads, "Focusing on a truly repellent real-life villain, The Most Hated Man on the Internets dive through some of the most sordid corners of the web is redeemed by a satisfying through line of justice served."
References
External links
2022 American television series debuts
2020s American documentary television series
American documentary television series about crime
American English-language television shows
Netflix original documentary television series
Works about the Internet
Television series by All3Media | The Most Hated Man on the Internet | [
"Technology"
] | 358 | [
"Works about the Internet",
"Works about computing"
] |
71,435,464 | https://en.wikipedia.org/wiki/Dysprosium%28III%29%20bromide | Dysprosium(III) bromide is an inorganic compound of bromine and dysprosium, with the chemical formula of DyBr3.
Preparation
Dysprosium(III) bromide can be obtained by reacting dysprosium with bromine:
2Dy + 3Br2 → 2DyBr3
Dysprosium bromide hexahydrate can be obtained by crystallization from its solution, which can be heated with ammonium bromide in vacuum to obtain the anhydrous form.
Dysprosium(III) oxide and aluminium bromide (in the form of Al2Br6 at a high temperature react a DyAl3Br12, which decomposes to dysprosium(III) bromide at a lower temperature:
Dy2O3 + Al2Br6 → Al2O3 + 2 DyBr3
Properties
Dysprosium(III) bromide is a white-gray hygroscopic solid that is soluble in water. It has a trigonal crystal structure of the bismuth(III) iodide type with space group R3 (No. 148).
References
Dysprosium compounds
Bromides
Lanthanide halides | Dysprosium(III) bromide | [
"Chemistry"
] | 262 | [
"Bromides",
"Salts"
] |
71,435,732 | https://en.wikipedia.org/wiki/David%20W.%20Wood | David W. Wood (born in 1967) is an American chemical engineer who is professor of chemical and biomolecular engineering at Ohio State University. Wood is also associated with the Department of Chemistry and Biochemistry and Molecular Biophysics Training Program.
Wood is best known for his work on self-removing affinity tag methods, which he first published in Nature Biotechnology while a Ph.D. student at Rensselaer Polytechnic Institute. This method was also patented as a part of a collaboration with co-inventors at the Wadsworth Center of the New York State Department of Health and Rensselaer Polytechnic Institute, including Marlene Belfort, Georges Belfort, Victoria Derbyshire, and Wei Wu.
Early life and education
Wood received dual undergraduate degrees in biology and chemical engineering from the California Institute of Technology in 1990. He worked as an undergraduate in the lab led by Frances H. Arnold. He earned his Ph.D. in chemical engineering from Rensselaer Polytechnic Institute in 2000. His doctoral co-advisors were Georges Belfort at Rensselaer Polytechnic Institute, and Marlene Belfort at Wadsworth Center.
Career
After obtaining his undergraduate degrees, Wood started working on high-viscosity mucopolysaccharide fermentation development at CP Kelco in San Diego, California. Soon after, he joined Amgen in 1991, the same year that Amgen received FDA approval for Neupogen. This recombinant protein cytokine drug induces white blood cell production to fight infections in immunocompromised cancer patients after undergoing chemotherapy or radiation treatment. Wood worked on the GMP fermentation team to manufacture Neupogen (rhG-CSF) between 1991 and 1993. Neupogen became one of the most successful biotech drugs at that time and second blockbuster for Amgen after Epogen.
In 1993, Wood joined the group of Georges Belfort as a Ph.D. student at Rensselaer Polytechnic Institute, where he worked primarily on mini-intein development for protein purification. During this time, he engineered the ∆I-CM intein, which was derived from Mycobacterium tuberculosis recA intein. After earning his Ph.D. he joined a team at Bristol Myers Squibb in Hopewell, New Jersey. This time he focused on the recovery and in vitro processing of transgenic monoclonal antibody therapeutics.
In 2001, Wood started his academic career at Princeton University as an assistant professor of chemical and biological engineering, where he continued his research focusing on self-removing tags, protein engineering, and applied biosensors. In 2009, he joined the Chemical and Biomolecular Engineering Department at Ohio State University as an associate professor and soon after was appointed as a full professor. While at the Ohio State, he continued to explore additional applications, including the development of multitarget sRNAs that can be used for metabolic engineering, and the modification of human butyrylcholinesterase for the degradation of the chemical warfare nerve agents in collaboration with the Battelle Memorial Institute.
Wood has joint appointments with Department of Chemistry and Biochemistry and the Molecular Biophysics Training Program at the Ohio State University. He is one of a small group of researchers worldwide focusing on intein implementation in various applications, along with Belfort and Tom Muir.
Wood's research focuses on developing new technologies by recombining protein domains, particularly in biopharmaceutical development and manufacturing. He has continued refining these methods for biopharmaceutical development and manufacturing, and his work has drawn funding from the DARPA BioMOD project, NIH, NSF and US Army Research Office, projects as well as several industry sponsors. Wood was also involved in the development of protein switches for biotechnology funded by the NSF Career Award. Wood is an author of over 60 publications, six issued patents, two additional patent applications pending and an additional dozen book chapters or edited volumes. His publications have been cited nearly 4000 times.
Wood is a member of the American Chemical Society, BIOT division, American Institute of Chemical Engineers, and International Society of Pharmaceutical Engineers.
Awards and honors
2003: NSF Career Award
2016: Lumley Engineering Research Award, Ohio State College of Engineering
Business
Protein Capture Science is a biotech start-up company commercializing a self-removing affinity tag technology for research and large-scale purifications of proteins. Wood and Izabela Gierach are co-founders of the company, based in Columbus, Ohio. The first line of the iCapTag products for protein purification was showcased in the Industry Innovators 2021-2022 Issue of the journal BioProcess International. Protein Capture Science was recently awarded several grants and funding, including highly competitive The Ohio Third Frontier Technology Validation and Start-Up Fund and the Concept Fund for extraordinary technologies by the Department of Development, State of Ohio.
References
External links
Izabela Gierach and David Wood - Protein Capture Science
A general capture and purification platform for tagless proteins based on a self-cleaving split-intein tag
Living people
1967 births
Ohio State University faculty
Chemical engineering academics
California Institute of Technology alumni
Rensselaer Polytechnic Institute alumni | David W. Wood | [
"Chemistry"
] | 1,049 | [
"Chemical engineering academics",
"Chemical engineers"
] |
71,437,357 | https://en.wikipedia.org/wiki/Ross%20508 | Ross 508 is a 13th magnitude red dwarf star, 11.2183 parsecs away. The Ross catalog is named after Frank Elmore Ross who published a first list of 86 high proper motion stars in 1925.
In 2022 it was discovered to have a super-Earth, Ross 508 b, orbiting every 10.77 days, detected by doppler spectroscopy.
References
External links
Planet Ross 508 b
NASA visualisations
M-type main-sequence stars
Serpens
Planetary systems with one confirmed planet
0585
508 | Ross 508 | [
"Astronomy"
] | 110 | [
"Constellations",
"Serpens"
] |
71,438,051 | https://en.wikipedia.org/wiki/Bowel%20Movement%20Bandit | The Bowel Movement Bandit (also known as the Ohio Pooping Bandit) is the alias of an unidentified man in the Kenmore neighborhood of Akron, Ohio, United States, who repeatedly defecated through the sunroofs of random people’s cars from 2012 to 2015. It has been speculated his name is Richie based on a Hot Topic membership card found at the scene. In total, the criminal defecated on 19 parked cars in driveways, as well as children's toys left in the front yards of homes. The criminal only stopped his public defecation spree after a photo of his face was captured by a hidden camera and released to the public.
History
Starting in May 2012, residents of the Kenmore neighborhood in Akron, Ohio, found feces on or in their cars. If their cars were locked, the perpetrator would defecate on the hood, windshield, gas tank covering, mirrors, windows, or handles of the car. However, if the cars were unlocked, the perpetrator would defecate on the interior of the car. In total, 19 people reported finding fecal matter on their car, but Lt. Rick Edwards of the Akron Police Department believes there are more victims.
On March 10, 2015, the face of the perpetrator was caught on a hidden camera set up by the father of a woman whose car was targeted by the perpetrator seven times. The hidden camera took a photo every twelve seconds. The photo of the perpetrator was released to the public by the Akron Beacon Journal on March 11, 2015. The perpetrator was estimated to be in his mid-40s when the photo was taken.
Partial list of incidents
See also
Crime in Ohio
References
Unidentified American criminals
Criminals from Ohio
21st-century American criminals
American male criminals
Water supply and sanitation in the United States
Defecation
2012 in Ohio
2013 in Ohio
2014 in Ohio
2015 in Ohio
2010s in Ohio
Year of birth unknown | Bowel Movement Bandit | [
"Biology"
] | 398 | [
"Excretion",
"Defecation"
] |
71,438,443 | https://en.wikipedia.org/wiki/Zachelmie%20trackways | The Zachelmie trackways are a series of Middle Devonian-age trace fossils in Poland, purportedly the oldest evidence of terrestrial vertebrates (tetrapods) in the fossil record. These trackways were discovered in the Wojciechowice Formation, an Eifelian-age carbonate unit exposed in the Zachełmie Quarry of the Świętokrzyskie Mountains (Holy Cross Mountains). The discovery of these tracks has complicated the study of tetrapod evolution. Morphological studies suggest that four-limbed vertebrates ("tetrapods" in the broad sense, also known as stegocephalians) are descended from a specialized type of tetrapodomorph fish, the epistostegalians. This hypothesis was supported further by the discovery and 2006 description of Tiktaalik, a well-preserved epistostegalian from the Frasnian of Nunavut. Crucial to this idea is the assumption that tetrapods originated in the Late Devonian, after elpistostegalians appear in the fossil record near the start of the Frasnian. The Zachelmie trackways, however, appear to demonstrate that tetrapods were present prior to the Late Devonian. The implications of this find has led to several different perspectives on the sequence of events involved in tetrapod evolution.
Discovery
In January 2010, a group of paleontologists published a paper which showed that the first tetrapods appeared long before any know fossils of Tiktaalik or other elpistostegids. This paper was accompanied by extensive supplementary material and also discussed in a Nature documentary on the origin of tetrapods. Their conclusions were based on numerous trackways (esp. Muz. PGI 1728.II.16) and individual footprints (esp. Muz. PGI 1728.II.1) discovered at the Zachełmie quarry.
A tetrapod origin of those tracks was suggested based on:
Distinct digits and limb morphology;
Trackways reflecting quadrupedal gait and diagonal walk;
No body or tail drag marks;
Very wide stride in relation to body length (much beyond that of Tiktaalik or any other fish);
Various size footprints with some unusually big (up to 26 cm wide) indicating body lengths of over 2.5 m.
Track-bearing layers were assigned to the lower-middle Eifelian based on conodont index fossil samples (costatus Zone) and "previous biostratigraphic data obtained from the underlying and overlying strata" with subsequent studies confirming this dating. The Eifelian stage is the first stage of the Middle Devonian, more than 10 million years older than the Frasnian-age Tiktaalik. It is far older than any known tetrapod fossils, and even older than most fossils of tetrapodomorph fish.
A reanalysis by Martin Qvarnström, Piotr Szrek, Per Ahlberg, and Grzegorz Niedźwiedzki, of the paleoenvironment of the Zachelmie trackways were reinterpreted as "a succession of ephemeral lakes with a restricted and non-marine biota, rather than a marginal marine environment as originally thought". This shows that the purported tetrapods associated with the trackways were likely capable of terrestrial locomotion.
Implications for tetrapod evolution
Tiktaalik's discoverers were skeptical about the Zachelmie trackways. Daeschler said that trace evidence was not enough for him to modify the theory of tetrapod evolution, while Shubin argued that Tiktaalik could have produced very similar footprints. In a later study Shubin expressed a significantly modified opinion that some of the Zachelmie footprints, those which lacked digits, may have been made by walking fish. However, Ahlberg insisted that those tracks could not have possibly been formed either by natural processes or by transitional species such as Tiktaalik or Panderichthys. Instead, the authors of the publication suggested that "ichthyostegalian"-grade tetrapods were the responsible trackmakers, based on available pes morphology of those animals. However, a paper published in 2015 that undertook a critical review of Devonian tetrapod footprints called into question the designation of the Zachelmie marks and instead suggested an origin as fish nests or feeding traces. A 2012 study on Ichthyostega biomechanics indicated that Zachelmie trackmakers were even more advanced than Ichthyostega in terms of adaptation for quadrupedalism. Grzegorz Niedźwiedzki's reconstruction of one of the trackmakers was identical to that of Tulerpeton.
Narkiewicz, co-author of the article on the Zachelmie trackways, claimed that the Polish "discovery has disproved the theory that elpistostegids were the ancestors of tetrapods", a notion partially shared by Philippe Janvier.
Spencer Lucas questions if the Zachelmie trackways were made by tetrapods due to the inconsistent size of the tracks and morphology of the manus and pes being inconsistent with known tetrapod trackways. The morphology of the trackways and the freshwater environmental setting are suggested to be consistent with fish feeding traces/nests.
Several new hypotheses have been suggested to resolve the origin and phylogenetic position of the elpistostegids (including Tiktaalik) relative to tetrapods:
Their phylogenetic position remains unchanged and the footprints found in the Holy Cross Mountains are attributed to tetrapods but as a result there are at least six long ghost lineages separating Zachelmie trackmakers from various elpistostegalian and ichthyostegalian species;
They were "late-surviving relics rather than direct transitional forms";
They were a result of convergent or parallel evolution. This would indicate that many of the apomorphies (derived traits) and striking anatomical similarities found in both digit-bearing tetrapods and elpistostegalians evolved at least twice, potentially for the same ecological utility. This would indicate that elpisostegids went extinct in the Late Devonian without any descendants, an "evolutionary dead-end" as some have phrased it. Homoplasy (convergent evolution) is considered responsible for several supposedly unique tetrapod features which are also found in non-elpistostegalian Paleozoic fish. The lobe-finned rhizodont Sauripterus has finger-like jointed distal radial bones, while the actinopterygian Tarrasius has a tetrapod-like spinal column with 5 axial regions.
See also
Tiktaalik
Evolution of tetrapods
Elpistostegalia
Stegocephalia
References
Eifelian life
Evolution of tetrapods
Vertebrate trace fossils
Devonian tetrapods
Stegocephalians
First 100 IUGS Geological Heritage Sites | Zachelmie trackways | [
"Biology"
] | 1,438 | [
"Phylogenetics",
"Evolution of tetrapods"
] |
75,719,523 | https://en.wikipedia.org/wiki/IEEE%20693 | The IEEE 693: Recommended Practice for Seismic Design of Substations. is a Institute of Electrical and Electronics Engineers standard. This standard is recognized also by American National Standards Institute, and is used mainly in the American Continent.
The goal of the standard is to provide a single set of rules and regulations that cover the seismic design of both new and existing electrical substations, hence leading to standardization. The standard provides the minimum requirements that the design of an electrical substation (except nuclear power plants) must adhere to. The norm includes the design of circuit breakers, transformers, disconnect and grounding switches, instrument transformers, circuit switches, surge arresters, and other equipment.
Contents
The norm contains the 8 chapters named below:
Overview
Normative references
Definitions, acronyms, and abbreviations
Instructions
General
Specifying this recommended practice in user's specification
Standardization of criteria
Selection of qualification level
Witnessing of shake-table testing
Optional qualification methods
Qualifying equipment by group
Inherently acceptable equipment
Shake-table facilities
Equipment too large to be tested in its in-service configuration
Report templates
Installation considerations
General
Equipment assembly
Site response characteristics
Soil-structure interaction
Support structures
Base isolation
Suspended equipment
Anchorage
Conductor induced loading
Interconnections with adjacent equipment
Observed component displacements
Decoupling equipment through flexible bus-work
Conductor installation
Short-circuit loads
Wind and ice loads
Qualification methods: an overview
General
Analysis methods
Static analysis
Static coefficient analysis
Response spectrum dynamic analysis
Time history dynamic analysis
Testing methods
Special test cases
Qualification method for specific equipment
Functionality of equipment
Qualification by seismic experience data
Response spectra
Damping
Design considerations
Structural supports, excluding foundations
Foundation analysis
Station service
Emergency power systems
Telecommunication quipment
Seismic performance criteria for electrical substation equipment
Introduction
Objective
Seismic qualification levels
High seismic level
Moderate seismic level
Low seismic level
Projected performance
Performance levels
High
Moderate
Low
Seismic qualification
High and moderate seismic qualification levels
Low seismic qualification level
Selecting the seismic level for seismic qualification
The norm specifies 3 seismic qualification levels (high, medium, low). The Zero Period Acceleration (ZPA) (a.k.a. Peak Ground Acceleration) for the high and the medium qualifications levels are set to be 0.5g and 0.25 respectively (no calculation is required for equipment with "low" qualification), where g stands for acceleration due to gravity. The Peak Acceleration (i.e. the peak of the Response Spectrum) at 2% damping is lower than 1.65g and 0.85g for high and medium qualification respectively, with the cutoff frequency defined as 33Hz.
The qualification is allowed through one of the following:
Shake Table Testing
Calculations
Experience
The norm suggests that most equipment in the same area be given the same qualification level (for interchangeability and redundancy).
Annex
There are a total of 22 annexes in the standard, 19 of which are normative, and the other 3 are informative.
History
The first version of the standard was released in 1997, with a revised version released in 2005 and later in 2018.
References
Institute of Electrical and Electronics Engineers | IEEE 693 | [
"Engineering"
] | 603 | [
"Electrical engineering organizations",
"Institute of Electrical and Electronics Engineers"
] |
75,719,981 | https://en.wikipedia.org/wiki/Caladinho%20Stream | The Caladinho Stream (Portuguese: Ribeirão Caladinho) is a watercourse that rises and flows in the Brazilian municipality of Coronel Fabriciano, in the state of Minas Gerais. The source is located near the Caladinho neighborhood and it runs for about 12 kilometers to its mouth in the Piracicaba River through the Industrial Novo Reno, Universitário, Aparecida do Norte, Morada do Vale, Aldeia do Lago and Santa Terezinha II neighborhoods. Its sub-basin covers 9 km2.
Pollution and the disorderly occupation of adjacent areas, especially during the 20th century, have caused a propensity to flooding during storms. Solutions are being developed through environmental education projects in the city's schools, hillside containment, drainage and reforestation works.
History and occupation
Urbanization in the area of the Caladinho Stream Sub-basin began in the 1960s, when the current Caladinho and Santa Terezinha II neighbourhoods were settled. Its name pays homage to Calado, the first name given to the current central area of Coronel Fabriciano. In the 1950s, the site underwent an earthmoving process for the implementation of the BR-381 highway (formerly MG-4), which cut through the city via Presidente Tancredo de Almeida Neves Avenue, but the stretch under federal concession was municipalized after being transferred outside the urban perimeter.
Many of the first lots in Coronel Fabriciano were located on the banks of watercourses, which were occupied without planning and resulted in a propensity to flooding during storms. Historically, Tancredo Neves Avenue has been one of the areas most affected by flooding caused by deficiencies in the flow of rainwater into the stream. The impacts of heavy rainfall were reduced after drainage works, the construction of water collection branches, the opening of galleries and gabions between 2007 and 2008.
The source of the Caladinho Stream is located in the Caladinho neighborhood, near an allotment. It runs from north to south through the neighborhoods of Industrial Novo Reno, Universitário, Aparecida do Norte, Morada do Vale, Aldeia do Lago and Santa Terezinha II, and flows into the Piracicaba River, covering a distance of around 12 km. In several stretches, including the area that intersects the interior of the campus of the Catholic University Center of Eastern Minas Gerais (Unileste), its course is channeled. Covering 9 km2, its sub-basin is bordered by the Caladão Stream Sub-basin and is part of the Piracicaba River Sub-basin, which is part of the Doce River Basin.
Ecology
Coronel Fabriciano's Ordinance Plan includes reforestation of the section inside the urban area, an increase in flow capacity and flood control. In 2004, the construction of a sewage treatment plant located between the Mangueiras and Santa Terezinha II neighborhoods to meet the demand from the city's waterways began to be studied. However, the project was suspended because residents in the area feared odors. In the following years, collection networks and interceptors were installed throughout the sub-basin.
Sewage from Coronel Fabriciano remained discharged directly into the watercourses bordering the urban perimeter without any management until 2019, when the construction of a treatment plant in Limoeiro, district of Timóteo, to supply 165,000 inhabitants in both cities was authorized. Despite the start of wastewater treatment, irregular dumping of garbage and debris on the banks of the spring can also be spotted in some stretches. At a distance of 300 meters from the source, the water is already considered to be outside the parameters of the National Environment Council (CONAMA) and cannot be consumed and contact avoided. There are a considerable number of people, including children, who use the water for irrigating vegetables, collecting recyclable material or even for leisure.
During the rainy season, which usually runs from October to April, the lower areas are affected by floods. Besides pollution, siltation, erosion and damage to biodiversity have been observed in the course of the stream. There are places demarcated as permanent protection areas (APP), but that have been occupied irregularly. The City Hall regularly weeds, cleans and removes debris from public spaces and provides disposal sites around the city for construction debris, furniture and branches. Environmental education projects in the city's schools, lectures, photographic exhibitions, video presentations and community meetings are held to alleviate the situation.
Gallery
See also
History of Coronel Fabriciano
References
Bibliography
Water streams
Bodies of water
Hydrology
Rivers of Minas Gerais | Caladinho Stream | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 966 | [
"Hydrology",
"Environmental engineering"
] |
75,721,630 | https://en.wikipedia.org/wiki/Works%20based%20on%20a%20copyright-free%20Mickey%20Mouse | The following is a list of creative works starring Mickey Mouse announced after Steamboat Willie, Plane Crazy and The Gallopin' Gaucho, released in 1928, entered the public domain in the United States on January 1, 2024. In January, multiple films and video games starring the iconic character were announced immediately. This list only includes works that received substantial media attention.
List
See also
Mickey au Camp de Gurs, 1942 comic booklet
Mickey Mouse in Vietnam, 1969 short film
Suicidemouse.avi, creepypasta that uses 1928's incarnation of Mickey Mouse
References
Public domain
Mickey Mouse
Mickey Mouse
Mickey Mouse
Mickey Mouse | Works based on a copyright-free Mickey Mouse | [
"Technology"
] | 126 | [
"Computing-related lists",
"Video game lists"
] |
75,721,694 | https://en.wikipedia.org/wiki/Stereum%20lobatum | Stereum lobatum (false turkeytail) is a basidiomycete crust fungus, which means it does not have the traditional mushroom gills nor stem, but rather grows flat or with shelf-like protrusions on wood. The spores are produced on basidia, just like the gilled mushrooms, but instead of gills, the hymenophore (spore-bearing surface) directly houses the reproductive parts.
In North America S. lobatum was long thought to be S. ostrea, but the recent accessibility to DNA sequencing has revealed that the two are distinct, and that S. ostrea is native to Indonesia and is not found in North America.
Description
Stereum lobatum grows in a fan-like shape with a narrowed base, and an upper surface that becomes zonate due to the felted hairs falling off and revealing the brown colour underneath. The overall shape, like most Stereum species, is fan or oyster-like, spreading outwards from the attachment to the wooden substrate. The cap is wide and the flesh is tough and thin. The spore print is white.
When bruised the pale brownish yellow will turn a bright yellow. Sometimes it may help to wet the bruised area to see the color change.
Similar species
The typical Stereum pore-less undersurface, will separate it from similar looking polypores such as Trametes (turkey tails), and thin fruiting bodies growing shelf like will separate it from most other crusts. The distinguishing features of S. lobatum is the combination of the yellow undersurface bruising, narrow base attachment, and the felted hairs. To see the felted hairs, a hand lens may be needed. A common way to examine the hairs is to fold a specimen in half, with the undersurface touching and splitting the hairy upper surface, and then examining the split section hairs to see if they stand up straight or are felted (as they are with S. lobatum).
Stereum subtomentosum is also a yellowing species, but the hairs are straight (as seen when folded and magnified with a hand lens), and the base has a usually broader attachment then S. lobatum.
Stereum fasciatum looks similar but does not stain yellow.
Stereum complicatum is usually smaller, does not stain yellow, and is brighter and more consistent orange.
Stereum hirsutum is also usually smaller and does not stain yellow.
Stereum ostrea is almost identical, apart from the fact that current studies show that it does not grow in North America.
Habitat and distribution
It grows on dead hardwood. It is found in Eastern North America and is likely pantropical.
References
Stereaceae
Fungi described in 1838
Fungus species | Stereum lobatum | [
"Biology"
] | 577 | [
"Fungi",
"Fungus species"
] |
75,722,285 | https://en.wikipedia.org/wiki/Doce%20River%20Basin | The Doce River Basin (Portuguese: Bacia do rio Doce) is located in the southeastern region of Brazil. According to the Doce River Basin Committee (CBH-Doce), it belongs to the Southeast Atlantic hydrographic region, has a drainage area of 86,175 square kilometers and covers all or part of 229 municipalities. 86% of the basin's area belongs to the state of Minas Gerais, in the Doce River Valley, and 14% to Espírito Santo.
Description
The main sources of the Doce River emerge in the Mantiqueira and Espinhaço mountain ranges. It is formed from the confluence of the Piranga and Carmo rivers between the municipalities of Ponte Nova, Rio Doce and Santa Cruz do Escalvado, in the state of Minas Gerais. It runs 853 kilometers to its mouth in the Atlantic Ocean at Linhares, on the coast of Espírito Santo.
The main tributaries of the Doce River on the left bank include the Piracicaba, Santo Antônio, Corrente Grande, Suaçuí Pequeno, Suaçuí Grande (in Minas Gerais), Pancas and São José (in Espírito Santo). On the right bank, the main affluents are the Casca, Matipó, Caratinga and Manhuaçu rivers (in Minas Gerais), and the Guandu, Santa Joana and Santa Maria do Rio Doce rivers (in Espírito Santo).
The Doce River Basin is composed of the main sub-basins of the Piranga, Piracicaba, Santo Antônio, Suaçuí (Pequeno and Grande), Caratinga and Manhuaçu rivers in Minas Gerais; and the Guandu, Santa Joana and Santa Maria do Doce rivers in Espírito Santo.
Climate
The topography and the sea directly affect the climatic characteristics of the Doce River Basin. In winter, the presence of the South Atlantic anticyclone favors the dominance of high pressure and prevents humidity from rising, forming the dry season. There is also the intrusion of polar air masses, which makes it difficult for temperatures to rise and instabilities to form. The terrain and the coastline are detrimental to the action of polar air and prevent the maintenance of low average temperatures (less than 18 °C) in the coldest month of the year at most altitudes below 300 meters. In summer, the temperature rises easily and the influence of tropical instabilities sets up the wet season.
The lower altitude areas, which include a large part of Espírito Santo and the valley bottoms formed by the course of the Doce River, have the highest temperatures and lowest average rainfall, ranging from 1,000 to 1,200 millimeters a year. These conditions characterize the semi-humid tropical climate (Aw, according to the Köppen-Geiger climate classification), present in the Steel Valley, Governador Valadares, Aimorés and Colatina. Throughout the basin, the highest altitudes are affected by annual rainfall of more than 1,200 millimeters and the lowest average temperatures, characterizing the subhumid temperate climate. The northern part, classified as Cwa, is characterized by hot summers, as in Itambacuri, São João Evangelista and Itabira. To the south, where forest plateaus dominate, summers are cool and the climate is designated as Cwb, as occurs in Viçosa, Ponte Nova and part of Caratinga.
Geomorphology and geology
The relief of the Doce River Basin is significantly rugged and characterized by the mares de morros. The course traces a lowland area called the Doce River interplateau depression, with average altitudes in its interior ranging from 250 to 500 meters on hills of medium slope. Until it reaches Governador Valadares, the Doce River follows a southwest–northeast course that intersects the geological unit known as the "Cinturão Atlântico", which is part of the Mantiqueira Province.
The dissected plateaus of south-central and eastern Minas Gerais occupy around 70% of the basin's area and have an undulating relief, including landforms such as ridges, valleys and hills. Other relevant geological units in the basin are the Espinhaço mountain range, to the east, composed of ruiniform structures shaped by fluvial erosion and dividing the basins of the Doce, São Francisco and Jequitinhonha rivers; and the Iron Quadrangle, at the western end, with altitudes ranging from 1,000 to 1,700 meters, exceeding 2,000 meters in the Caraça mountain range, under rocks dissected by the geological structure. However, the highest altitude in the basin area is found in Iúna, in Espírito Santo, at 2 627 meters.
The subsoil has several aquifers, but the majority (92.6% of the total) are fractured aquifers with low water productivity. Around 3.5% is concentrated in the coastal region of Espírito Santo, where productivity is potentially high but variable. The alluvial aquifer located under the Steel Valley, which accounts for 3% of the mass, is the only one with high productivity and flow, serving as the main source of public supply. The rest of the aquifers are karst or double porosity types, with variable water productivity.
Pedology
In the Doce River depression, rocks from the gneissic-magmatic-metamorphic complex predominate, including biotite-gneiss, granitic and granite-gneissic rocks; to a lesser extent, rocks from the charnockitic complex. The granite-gneiss rocks of the Precambrian basement under crystalline structures are predominant in the dissected plateaus. In the Espinhaço mountain range, the composition is predominantly quartzite rocks, while in the Iron Quadrangle, itacolumite, itabirite and quartzite ridges stand out.
Soils of the red-yellow latosol and red-yellow acrisol classes predominate in the basin. Latosols, registered from flat to mountainous terrain, are drained, dystrophic and alkalic (with a high concentration of aluminum), and formed mainly from gneissic and magmatic rocks, schists and sandy-clay deposits. Acrisol is formed from gneissic and magmatic rocks, charnoquites and schists and is also found on flat to mountainous terrain but is more common in hilly areas. It is the most susceptible to erosion, but also the most suitable for some of the region's agricultural crops, such as corn, rice, coffee and pastures. Humic latosols, litholic soils, cambisols and rock outcrops are found to a lesser extent.
Environmental crime
On November 5, 2015, a mining tailings dam collapsed in the subdistrict of Bento Rodrigues, in the municipality of Mariana, in the state of Minas Gerais, and caused a torrent of 62 million cubic meters of mining tailings discharged into the Doce River. The event was considered the biggest environmental disaster in Brazil's history and the worst tailings dam accident ever recorded in the world.
See also
Mariana dam disaster
Brumadinho dam disaster
References
Bibliography
Landforms of South America
Landforms of Brazil
Drainage basins of Brazil
Hydrology
Water streams
Water and the environment | Doce River Basin | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 1,525 | [
"Hydrology",
"Environmental engineering"
] |
75,723,014 | https://en.wikipedia.org/wiki/GJ%203929 | GJ 3929, also known as Gliese 3929 and TOI-2013, is a red dwarf star located 51.6 light-years from Earth, in the constellation Corona Borealis. With an apparent magnitude of 12, it is not visible to the naked eye. In 2022, two exoplanets were detected orbiting the star.
Characteristics
GJ 3929 is a red dwarf of spectral type M3.5V, having a radius of , a mass of and a temperature of . With an apparent magnitude of 12.7, it cannot be visible with the naked eye, neither with a small telescope. It has no companion stars. The age of GJ 3929 is estimated at 2.2 to 12.2 billion years.
The star is located in the northern hemisphere, approximately 50 light years from Earth, in the direction of the constellation Corona Borealis. Its closest neighbor is the red dwarf G 179–57, located at a distance of 3.9 light years.
Planetary system
In 2022, two exoplanets were detected orbiting around GJ 3929. The innermost, GJ 3929 b, is a rocky planet just 9% larger than Earth, while the outermost, GJ 3929 c, is a sub-Neptune with 5.7 times the mass of Earth. Both planets orbit below the star's habitable zone.
GJ 3929 b
The innermost planet, GJ 3929 b (TOI-2013 b), is an Earth-sized planet discovered by the transit method. Orbiting its star at a distance of , the planet is located in its star's Venus zone, and completes a revolution every 2 days and 15 hours. The planet's equilibrium temperature is calculated at , and it receives a planetary insolation 17 times greater than what the Earth receives from the Sun.
The planet's mass is calculated at according to photometric observations using the NEID spectrometer. Observations using the ARCTIC imager, plus photometry from TESS and LCOGT, constrained the planet's radius to . This radius makes GJ 3929 b very similar to Earth in terms of size.
Due to the apparent brightness of the host star, and its small size, GJ 3929 b is an excellent planet for atmospheric study with the James Webb Space Telescope.
It was discovered by a team of astronomers led by Jonas Kemmer. They reported an planetary transit signal in the host star's light curve. Subsequent observations, mainly with the CARMENES spectrograph, revealed that this transit signal is an orbiting exoplanet.
The outermost planet, GJ 3929 c (TOI-2013 c) is a Sub-Neptune discovered using the radial velocity method. It orbits its star at a distance of , 3 times further away than , but still below GJ 3929's habitable zone, completing an orbit every 15 days.
Its minimum mass is , while its radius is unknown. Estimates using mass-radius relationship derive a radius of 2.26 . Its equilibrium temperature is calculated at , and it receives a planetary insolation 68% greater than what the Earth receives from the Sun.
GJ 3929 c was first identified in radial velocity data, which indicated the existence of another planet besides GJ 3929 b. Initially, it was just an exoplanet candidate, but it was later confirmed by a team led by Corey Beard. Because its orbital period (15 days) is far from its star's rotation period (122 days), it is unlikely that the radial velocity signal is actually an artifact of its parent star's activity and rotation.
See also
Gliese 436
Notes and references
3929
M-type main-sequence stars
Corona Borealis
Planetary systems with two confirmed planets
188589164
J15581883+3524236 | GJ 3929 | [
"Astronomy"
] | 784 | [
"Corona Borealis",
"Constellations"
] |
75,723,854 | https://en.wikipedia.org/wiki/Plastistone | Plastistone is the umbrella term for rocks that have fused with plastic. At the end of 2023 there were numerous sightings of green-colored plastic seemingly melted to rocks. It forms from plastic that floats through the ocean and melts to the rocks over time. So far, the stone has appeared on 5 continents. It was recently spotted in March 2023 on the Brazilian remote island of Trindade and has been seen in Hawaii a decade before.
Further reading
References
External link
Rocks
Artificial stone
Plastics and the environment
Pollution | Plastistone | [
"Physics"
] | 108 | [
"Rocks",
"Physical objects",
"Matter"
] |
75,724,052 | https://en.wikipedia.org/wiki/Duesenberg%2016-valve%20straight-4%20aero%20engine | The Duesenberg 16-valve straight-4 aero engine was based on the company's earlier engine of a similar configuration used for automotive racing. Completed in 1916, the first two engines were delivered to the Gallaudet Aircraft Company for use in their D-1 maritime patrol aircraft later that year.
Citations
Bibliography
Straight-4 aero eninge
Aircraft engines
Straight-four engines | Duesenberg 16-valve straight-4 aero engine | [
"Technology"
] | 77 | [
"Engines",
"Aircraft engines"
] |
75,724,327 | https://en.wikipedia.org/wiki/Advisory%20Committee%20for%20Earth%20Observation | The Advisory Committee for Earth Observation (ACEO) is the senior advisory body to the European Space Agency's (ESA's) Director of Earth Observation (EO) Programmes. The Advisory Committee acts as the representative of the Director General of the European Space Agency on all matters concerning Earth observation-based Earth Sciences in the Earth Observation Programmes of ESA.
Role
ACEO is the main interpreter of the views and needs of the European scientific community as regards access to space experimentation and EO data exploitation in the Earth science community. Its main tasks are to advise and/or make recommendations on:
the needs of the scientific community for remote observations of Earth;
scientific activities during the development, implementation and exploitation of the approved projects of ESA's Earth Observation programmes
the formulation and updating of medium and long-term Earth Observation Science Strategy in Europe in regard to the interests of the scientific community;
the priorities of the scientific community in the selection (and extension) and formulation of future Earth Observation missions, and the associated Calls for Proposals for new mission ideas;
the science aspects in relation to the evolution of operational Earth Observation missions in terms of the space segment (planning, succession, Long-Term Scenario), the operational services and the impact of operational missions on EO Science;
the contribution of ESA EO missions to address major societal issues;
ESA's EO system architect role, considering EO missions developed at National level;
the impact of NewSpace on ESA EO programmes;
the scientific studies and activities required to lay the foundations for future missions;
the selection of new scientific projects.
The ACEO has the highest-level advisory capacity, through the Director of Earth Observation Programmes (D/EOP), for matters to be treated at the level of the Programme Board for Earth Observation (PB-EO), which may also request advice on particular issues of a scientific nature.
Membership
ACEO is composed of invited members who are senior European scientific experts and ex-officio representatives of relevant stakeholder bodies, and is managed by the ACEO Secretariat in the Earth and Mission Science Division. ACEO members are selected ESA Executive to achieve diversity and balance in scientific expertise across the relevant Earth science disciplines, from within ESA Member States, and Canada, Latvia, Lithuania, Slovenia, or Slovakia.
Membership appointments are for a period of three years with the possibility to extend to a maximum of five years. The tenure of the chair is for three years, independent of previous normal membership, with the possibility of a one-year extension.
The Chair of the PB-EO is invited, ex officio, to attend the meetings of the ACEO. Furthermore, representatives of other ESA Directorates’ Science Advisory Committees may be invited to attend.
Representatives of scientific or professional organisations with a stake in Earth Observation (e.g. European Space Sciences Committee (ESSC) of the European Science Foundation, whose expertise may be required by ACEO to properly fulfil its functions can also be invited, ex-officio and Ad Personam, to attend the meetings.
Operating Procedure
The Committee meets at dates and places jointly agreed between the chair and the Director of Earth Observation Programmes.
ACEO provides advice and/or makes recommendations on the items referred to it by the Director of Earth Observation Programmes. Members of the Committee may however raise issues they wish to discuss.
The Chair of the ACEO reports on the committee's recommendations at the meetings of the PB-EO. The Chair of PB-EO can make a request to the Director of Earth Observation Programmes for ACEO to carry out specific actions in the framework of its mandate.
The ACEO Secretariat is managed by ESA's Earth and Mission Science Division.
Past Chairpersons
2023–present: Prof. R. Forsberg
2020-2023: Dr. F. Rabier
2018-2021: Prof. M. Visbeck
2014-2018: Prof. W. Mauser
2010-2014: Prof. A. O'Neill
2007-2010: Prof. J. Johannessen
2003-2007: Prof. H. Graßl
1999-2003: Prof. L. Bengtsson
1996-1999: Prof. G. Mégie
History
The ACEO was established in 2018 to replace the former Earth Science Advisory Committee (ESAC) as the senior advisory body to the Director of Earth Observation.
The former Earth Science Advisory Committee had been in place operating as the main science advisory body from the inception of the ESA Living Planet Programme in 1996 until 2018. Prior to that the Earth Observation Advisory Committee (EOAC), created in 1981, had been the senior scientific advisory body to the Application Satellites Directorate on programmes, projects, studies and application of this field.
References
European Space Agency
Satellite imaging sensors
Satellite imagery
Space agencies
European space programmes
European Space Agency programmes | Advisory Committee for Earth Observation | [
"Engineering"
] | 971 | [
"Space programs",
"European space programmes"
] |
75,724,341 | https://en.wikipedia.org/wiki/Strainer%20arch | A strainer arch (also straining arch) is an internal structural arch built to relieve the inward pressure off the spanned vertical supports (providing a "buttress", thus also called buttressing arches), usually as an afterthought to prevent the supports from imploding due to miscalculation. In the past they were frequently adorned with decoration, with one of the best examples provided by Wells Cathedral. Strainer arches can be "inverted" (upside-down) while remaining structural.
The typical construction of Romanesque and Gothic churches includes east-to-west arcades, where each arch is buttressed by its neighbours. The issue at the east end is resolved using the buttressing of an apse to the choir, while at the west end a massive "westwork" is used. In a large church a similar problem occurs at the crossing, where the arcades of the nave and choir have to terminate. A "spectacular" solution for the crossing buttressing issue at Wells Cathedral was found by William Joy (1338, 17 years after completion). A similar arrangement was added to both crossings of Salisbury Cathedral more than 100 years after the completion of most of the building, but shortly after the addition of a tower (1380). The straining arches were added in the east-west direction, thus being unobtrusive when viewed from the nave. The arrangement at the east crossing (built in 1388) is similar to the one at Wells, while the great crossing uses a single-arch strainer design. In Bristol Cathedral the strainer arches are used to carry the thrust from the central vault over the aisles, as in this hall church building the width of the aisles is half that of the nave, therefore the transverse forces cannot be balanced in an arcade-like fashion.
See also
Flying buttress, an outside arch built to relieve the horizontal thrust
Girder, a horizontal support beam
Flying arch, used in sites such as railway cuttings
References
Sources
Arches and vaults | Strainer arch | [
"Engineering"
] | 406 | [
"Architecture stubs",
"Architecture"
] |
75,725,620 | https://en.wikipedia.org/wiki/O%20Puppis | The Bayer designations O Puppis and o Puppis are distinct and refer to two different stars in the constellation Puppis:
O Puppis (HD 65685, HR 3121) a red giant star with an apparent magnitude of 5.17
o Puppis (HD 63462, HR 3045, Omicron Puppis), a B-type main-sequence star which designation was misinterpreted as Omicron Puppis
Puppis, O
Puppis | O Puppis | [
"Astronomy"
] | 99 | [
"Puppis",
"Constellations"
] |
75,725,621 | https://en.wikipedia.org/wiki/Kappa%20Indi | The Bayer designation Kappa Indi (κ Indi / Kappa Ind / κ Ind) can refer to two different stars in the constellation Indus:
κ1 Indi, an A-type main sequence variable star more commonly known as BG Indi, with an apparent magnitude of 6.12
κ2 Indi, a red giant with an apparent magnitude of 5.62
References
Indi, Kappa
Indus (constellation) | Kappa Indi | [
"Astronomy"
] | 85 | [
"Indus (constellation)",
"Constellations"
] |
75,725,948 | https://en.wikipedia.org/wiki/James%20Benjamin%20Rosenzweig | James Benjamin Rosenzweig is an experimental plasma physicist and a distinguished professor at the University of California, Los Angeles (UCLA). In the field of plasma wakefield acceleration, he is regarded as the father of the non-linear "blowout" interaction regime, where a laser beam, when fired into a plasma at intense levels, expels electrons from the plasma and creates a spherical structure that can effectively focus and accelerate the plasma.
Rosenzweig's research on accelerator technologies and light source development is also considered to be pioneering in the field. For his research on plasma acceleration and electron beams, Rosenzweig was inducted as a fellow of the American Physical Society in 1998. He is the recipient of the 2007 Free Electron Laser (FEL) Prize, 2022 Advanced Accelerator Prize, and the 2023 Hannes Alfvén Prize.
Early life and career
Rosenzweig received his Ph.D. from the University of Wisconsin–Madison in 1988.
From 2009 to 2014, Rosenzweig served as the chair of the UCLA Department of Physics and Astronomy. He is the director of the UCLA's Particle Beam Physics Laboratory, which primarily focuses on exploring the fundamental aspects of high brightness, ultra-fast relativistic electron beams.
Rosenzweig co-founded several industrial accelerator companies, including RadiaBeam Technologies in 2003.
Scientific contributions
Rosenzweig's research specializes in advanced accelerator, beam, and radiation techniques, along with their applications across various scientific disciplines. His research has applications in very high field accelerators based on lasers, wakefields, plasmas and dielectrics, as well as the production of radiation in free-electron lasers and Compton scattering sources, with applications ranging from high field pumps for studying non-equilibrium high field phenomena to atomic-molecular level ultra-fast imaging techniques.
Rosenzweig has written a textbook, Fundamentals of Beam Physics, which emphasizes unity of concepts between charged particles and laser beams.
Honors and awards
Rosenzweig was awarded the Sloan Research Fellowship in 1993. He is a recipient of the SCC and Wilson Fellowships.
In 1998, Rosenzweig was inducted as a fellow of the American Physical Society for his "experimental and theoretical work on plasma wakefield acceleration and focusing techniques, and developments in the theory and diagnosis of high brightness, short pulse electron beams".
In 2007, Rosenzweig was jointly awarded the Free Electron Laser (FEL) Prize with Ilan Ben-Zvi. He was awarded the 2022 Advanced Accelerator Prize
In 2023, Rosenzweig, along with Pisin Chen and Chandrashekhar J. Joshi, jointly received the Hannes Alfvén Prize from the European Physical Society. They were honored for inventing and pioneering the technique of beam-driven plasma wakefield acceleration (PWFA).
Publications
Books
References
Living people
Year of birth missing (living people)
Place of birth missing (living people)
Plasma physicists
University of Wisconsin–Madison alumni
University of California, Los Angeles faculty
Fellows of the American Physical Society | James Benjamin Rosenzweig | [
"Physics"
] | 603 | [
"Plasma physicists",
"Plasma physics"
] |
75,726,787 | https://en.wikipedia.org/wiki/Isofalcarintriol | Isofalcarintriol (IUPAC name (3S,8R,9R,E)-heptadeca-10-en-4,6-diyne-3,8,9-triol) is a polyacetylene contained in the root of carrots (Daucus carota).
References
Exercise biochemistry
Anti-aging substances
Cellular respiration
Polyenes
Triols | Isofalcarintriol | [
"Chemistry",
"Biology"
] | 87 | [
"Cellular respiration",
"Exercise biochemistry",
"Anti-aging substances",
"Senescence",
"Biochemistry",
"Metabolism"
] |
75,727,453 | https://en.wikipedia.org/wiki/Cation%E2%80%93cation%20bond | Cation-cation interactions often occur between molecular cations of transition metals and f-elements (so-called yl cations). They are distinguished as a separate type of intermolecular interactions, since without taking them into account, cations usually repel each other in accordance with Coulomb's law.
Cation-cation interactions in f-elements
Of particular interest are cation-cation interactions between actinide cations - uranium, in the form of uranyl UO22+, neptunium in the form of neptunoyl NpO22+, plutonium and americium, which are essentially a manifestation of specific complex formation. They are a special case of intermolecular interactions that occur in molecular ions. It was first discovered when studying the behavior of netunium(V) compounds in solutions of uranyl perchlorate. Great impact to crystallochemistry of cation-cation bonds was made by Mikhail Grigoriev.
The cation-cation interaction [NpO2]+ determines the crystal structure of Np(V) compounds, and the strength of cation-cation bonds between neptunoyl ions in a solid is comparable to the strength of ordinary bonds with acid ligands, although in an aqueous solution, apparently, the role There are somewhat fewer of these connections. In an organic solution, the intensity of C-C interactions can remain high [1]. In the absence of mutual coordination of neptunium ions, Np(V) compounds can exhibit both structural similarity with An(VI) compounds and fundamental differences (showing a tendency to unite Np coordination polyhedra through common equatorial edges. Cation-cation interactions can be detected not only by data from structural studies, but also according to vibrational spectroscopy data. For uranyl, cation-cation interactions are also recorded in the gas phase.
Cation-cation interactions in transition metal ions
For transition metals, cation-cation interactions appear in nitrene complexes. Nitrenium ligands provide an excellent platform for the simple and efficient synthesis of extremely rare complexes that have positively charged ligands coordinated to positively charged metals to form stable cation-cation and cation-dication coordination bonds.
References
Cations
Chemical bonding | Cation–cation bond | [
"Physics",
"Chemistry",
"Materials_science"
] | 477 | [
"Matter",
"Condensed matter physics",
"nan",
"Cations",
"Chemical bonding",
"Ions"
] |
75,728,589 | https://en.wikipedia.org/wiki/Sewage%20discharge%20in%20the%20United%20Kingdom | The issue of sewage discharge in the United Kingdom has attracted legal, media and political attention. UK water companies periodically release sewage into rivers and coastal waters, leading to health warnings on recreational beaches. This is permitted during heavy rainfall as the sewage system exceeds capacity, but some companies have been suspected of illegally dumping on dry days. The Environment Agency subsequently launched criminal investigations into several companies. The introduction of stricter legislation has been debated in parliament. Southern Water was fined £90m in 2021 and Thames Water was fined £3.4m in 2023 for illegal dumping.
Sewage discharge
The UK has a combined sewage system, meaning rainwater and wastewater are discharged through the same pipes. During heavy rainfall, this system's capacity can be exceeded, leading to water companies discharging sewage into rivers and lakes. Some water companies also have been suspected of illegally discharging on dry days. Sewage discharge has led to health warnings at popular recreational beaches.
According to unpublished data presented to the high court, raw sewage was released 372,533 times over 2.7 million hours in 2021 and 301,000 times over 1.75 million hours in 2022.
Investigations and industry responses
In 2021, Southern Water pled guilty and was fined £90m, a record amount, for "deliberately dumping raw sewage" into the ocean because it was cheaper than treating it. Between 2010 and 2015, Southern Water illegally released sewage on 6,971 occasions at 17 sites in Hampshire, Kent and West Sussex. The investigation was the biggest undertaken by the Environment Agency in its history.
In 2023, Water UK, the industry body, issued an apology for sewage discharge and announced a £10bn plan to modernise the Victorian-era sewage system, whilst Thames Water was fined £3.4m. The Environment Agency also launched a criminal investigation into all water companies.
In August 2024, Ofwat, the British regulator for the water and sewerage industry, put forward a proposal to fine £168m Thames Water, Yorkshire Water and Northumbrian Water because they released sewage too early ahead of heavy rain falls.
Political responses
In 2022, a proposed amendment to the Environment Bill was defeated 265 to 202 votes by members of parliament. This change would have made explicit that water companies must ensure raw sewage is not discharged. In April 2023, Shadow Secretary of State for Environment, Food and Rural Affairs Jim McMahon from the Labour Party pushed for a debate and vote in the House of Commons for a proposed Water Quality (Sewage Discharge) Bill, which would introduce automatic fines to water companies for the practice. The bill failed to garner support from the Conservative Party.
The Labour government is currently planning new legislation to address the proposal of Ofwat.
See also
Environmental issues in the United Kingdom
Thames Water
References
Water pollution in the United Kingdom
Water supply and sanitation in the United Kingdom
Environmental issues in the United Kingdom
Environmental controversies
2020s controversies
Controversies in the United Kingdom
Environmental disasters in the United Kingdom
Sewerage
2020s disasters in the United Kingdom
Waste disposal incidents
Pollution events in 2021
Pollution events in 2022
2020s in British politics | Sewage discharge in the United Kingdom | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 619 | [
"Sewerage",
"Environmental engineering",
"Water pollution"
] |
75,729,425 | https://en.wikipedia.org/wiki/Robot%20Constitution | The Robot Constitution is a security ruleset part of AutoRT set by Google DeepMind in January 2024 for its AI products. The rules are inspired by Asimov's Three Laws of Robotics.The rules are applied to the underlying large language models of the helper robots.
Rule number 1 is a robot “may not injure a human being” .
References
AI software
Existential risk from artificial general intelligence
Google | Robot Constitution | [
"Technology"
] | 85 | [
"Existential risk from artificial general intelligence"
] |
75,729,774 | https://en.wikipedia.org/wiki/Steven%20Detweiler | Steven L. Detweiler was a theoretical physicist and professor of physics at the University of Florida best known for proposing pulsar timing arrays as a means to detect gravitational waves, an idea that led to the discovery of a stochastic gravitational wave background in 2023.
Background
Detweiler received his bachelor's degree from Princeton University in 1969 and his Ph.D. from the University of Chicago in 1976 under the supervision of James R. Ipser. In 2013, he was elected to a fellowship of the American Physical Society in recognition of his many and varied contributions to gravitational physics.
Detweiler's research focused on the dynamics of stars and black holes, as well as on the production and observation of gravitational waves. In 1975 together with Subrahmanyan Chandrasekhar, Detweiler calculated the effects of fluctuations on black holes. This is important for understanding the stability of black holes, as well as the later stages of the dynamics of black hole mergers. In 1979, Detweiler proposed the idea of a pulsar timing array to measure gravitational waves with wavelengths on the scale of light-years.
This built upon an earlier proposal by Mikhail Sazhin to use individual pulsars.
The idea was first taken up experimentally by Foster and Backer in 1990, and today globally there are five active pulsar timing array experiments. In 2023, this idea led to the discovery of a stochastic gravitational wave background by the NANOGrav experiment and other pulsar timing array experiments.
References
External links
Personal homepage
2016 deaths
Theoretical physicists | Steven Detweiler | [
"Physics"
] | 315 | [
"Theoretical physics",
"Theoretical physicists"
] |
75,731,068 | https://en.wikipedia.org/wiki/Ministry%20of%20Water%2C%20Irrigation%20and%20Electricity%20%28Ethiopia%29 | The Ministry of Water, Irrigation and Electricity (Amharic: የውሃ፣ መስኖና ኤሌትሪክ ሚኒስቴር) is an Ethiopian government department responsible for management of water resources, water supply and sanitation, irrigation and energy. It was established in 2010.
Overview
The ministry was established in 2010. From 2021 to 2024, Aisha Mohammed was appointed by Prime Minister Abiy Ahmed as minister on 6 October 2021. On 20 May 2024, Abraham Belay succeeded as the minister while Aisha replaced his previous role of Defense Minister.
List of ministers
Seleshi Bekele (16 October 2018 – 6 October 2021)
Aisha Mohammed (6 October 2021 – 20 May 2024)
Abraham Belay (20 May 2024 – present)
References
Government ministries of Ethiopia
2010 establishments in Ethiopia | Ministry of Water, Irrigation and Electricity (Ethiopia) | [
"Engineering"
] | 155 | [
"Energy organizations",
"Energy ministries"
] |
75,731,313 | https://en.wikipedia.org/wiki/Metamitron | Metamitron is an organic compound used as a selective pre- and post-emergence herbicide in sugar beets. It is used in the European Union for weed suppression in sugar beets. Metamitron is marketed under the trade name Goltix by ADAMA in Europe, the United Kingdom, New Zealand, and South Africa.
Metamitron is a triazinone herbicide. It possesses a triazine ring like other organic compounds that use cyanuric chloride as a precursor. It is a modification of the chemical 1,2,4-triazin-5(4H)-one, with methyl, amino, and phenyl group substitutions at positions 3, 4, and 6.
Metamitron is in the HRAC Mode of action Group 5. It functions as an inhibitor of PSII by binding to serine 264 on the D1 protein. Resistance to metamitron has been found in Chenopodium album growing as weeds among sugar beet fields in Belgium, caused by a mutation in serine 264.
Metamitron has moderate acute oral and inhalation toxicity.
See also
Atrazine
Hexazinone
Metribuzin
References
Herbicides
Triazines | Metamitron | [
"Biology"
] | 249 | [
"Herbicides",
"Biocides"
] |
75,731,359 | https://en.wikipedia.org/wiki/Birch%20wood | Birch wood is a type of wood of the birch. Birch wood is pale yellow-brown wood having a close, straight grain and uniform texture that finishes to a smooth surface. Sometimes it is dyed to imitate mahogany. This type of wood is used for among others firewood, turnery, furniture, cabinetry, tools handles, hoops, plywood, flooring and shoe heels.
References
Wood by type | Birch wood | [
"Physics"
] | 85 | [
"Materials stubs",
"Materials",
"Matter"
] |
75,732,502 | https://en.wikipedia.org/wiki/Funicular%20curve | In architecture, the funicular curve (also funicular polygon, funicular shape, from the , "of rope") is an approach used to design the compression-only structural forms (like masonry arches) using an equivalence between the rope with hanging weights and standing arch with its load. This duality was noticed by Robert Hooke in 1675 ("as hangs the flexible line, so, but inverted, will stand the rigid arch"). If the hanging rope carries just its own weight (in this case it is usually called a "chain" and is equivalent to a free-standing arch with no external load), the resulting curve is a catenary.
In graphic statics, a funicular polygon is a graphic method of finding out the line of action for a combination of forces applied to a solid body at different points, a complement to the force polygon used to obtain the value and direction of the resultant force. Both polygons were introduced by Pierre Varignon (Nouvelle Mecanique ou Statique, 1725) and became the basis of the graphic statics in the second half of the 19th century.
Hanging chain model
Multiple ropes with weights can be connected together forming a hanging chain model of a complete structure. The uses of this "outlandish", complicated in comparison with even pre-computer techniques, like graphic statics, method were rare, yet interesting. Usually the technique was used for planar structures as well as the ones with rotational symmetry, like domes. The method can also be applied to arbitrary three-dimensional structures, as first shown by Gaudi while designing the church of Colònia Güell. Gaudi had built a 1:10 scale hanging chain model of the church that did not survive. He also used a smaller copy that was at the time stored in the Sagrada Família basilica. This small model, on exhibit at the museum of the basilica, is often misinterpreted as a model of the basilica itself.
See also
Mathematics and architecture
References
Sources
Structural engineering | Funicular curve | [
"Engineering"
] | 412 | [
"Structural engineering",
"Construction",
"Civil engineering",
"Architecture stubs",
"Architecture"
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75,733,128 | https://en.wikipedia.org/wiki/Autogenerative%20high-pressure%20digestion | Autogenerative high-pressure fermentation (AHPD) is a biogas production technique that operates under elevated gas pressure. This pressure is naturally generated by the bacteria and archaea through the gases they release. First described by R. Lindeboom of University of Wageningen (WUR) in 2011, a batch reactor was pressurized to 58 bar, yielding a methane concentration of 96% in the resulting biogas. This method is also commonly referred to as High Pressure Anaerobic Digestion (HPAD) in scientific literature.
AHPD leverages the higher solubility of carbon dioxide (CO2) at 0.031 mol/L/bar compared to methane (CH4) at 0.0016 mol/L/bar. This difference allows more CO2 to dissolve in the digestate, while hydrogen sulfide (H2S) also dissolves more efficiently under pressure. The result is biogas with a higher methane content, which requires less upgrading to meet natural gas standards, ultimately reducing processing costs.
Microbial composition
Individual species of microorganism have different optimal conditions in which they grow and replicate most rapidly.There is a specificrange around that optimum in which a specie is able to survive. Factors such as the pH, temperature, osmotic pressure (often caused by salinity) all contribute to the optimal condition of all microorganisms. For example, in terms of pressure, some species are able to survive in extremophile conditions such as extreme radiation, temperature, salinity or pressure. Piezophile microorganisms have their optimal growth condition at a pressure equal to or above 10 megapascals (99 atm; 1,500 psi). Some bacteria and archaea have adapted to life in the deep oceans, where the pressure (Hydrostatic pressure) is much higher than at sea level. For example, the methane-producing archaea species Methanocaldococcus, Methanothermococcus, Methanopyrus and Methanotorris have been found in hydrothermal vents in the ocean floor. Research at the University of Groningen (RUG) has shown that the bacterial community is affected by pressure from composition changes. This makes it possible to influence the anaerobic digestion process.A further development of this technique is the addition of hydrogen gas to the reactor. According to Henry's law, this gas also dissolves more at increased pressure. The result is that it can be better absorbed by bacteria and archea. In turn, it converts the hydrogen gas with the already dissolved carbon dioxide into additional methane. This combination of techniques was described in detail by Kim et all in 2021, known to be a process called biological methanation. On Michael Liebreich's hydrogen ladder 5.0, this form of biogas upgrading is at step C. This is considerably higher than applications as fuel in vehicles. These are spread over steps D to G.
Although the technique is usually used as a fermentation process for thick liquid flows and solid biomass, it can also be applied as anaerobic Wastewater treatment. In South Korea, they have succeeded in operating a UASB reactor (a form of anaerobic wastewater treatment) at 8 Bar. A biogas was then created with a methane content of 96.7%. A remarkable finding was that the grains in the sludge that are so similar in characteristic of the UASB technique were well preserved. This was because more Extracellular polymeric substance (EPS) was formed in the biofilm. Microorganisms make these to protect themselves against difficult conditions, in this case the extreme pressure.
See also
Biogas
Anaerobic digestion
References
Sustainable energy
Biogas technology
Anaerobic digestion | Autogenerative high-pressure digestion | [
"Chemistry",
"Engineering",
"Biology"
] | 769 | [
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75,733,801 | https://en.wikipedia.org/wiki/V%C4%81ra%20%28astronomy%29 | In Indian calendrical systems, vāra (or, vāsara) denotes the week-day. It is one of the five elements that constitute the traditional almanacs called Pañcāṅga-s the other four being Nakshatra, Tithi, Karaṇa and Nityayoga. The concept of week, the unit of time consisting of seven days, is indigenous to Indian civilisation. The concept was probably borrowed by Babylonians and its use predates the use of the twelve zodiacal signs in Indian civilazation. The concept finds mention in Atharva Veda. The seven week-days are named after the seven classical planets as in the ancient Greek and Roman traditions.
The rationale behind the naming of week days
The historical rationale behind the current naming of the week-days is astrological in origin and it can be summarized as given below. Surya-Siddhānta and Āryabhaṭīya have also indicated this rationale. Sūrya Siddhānta, in Chapter XII Bhūgolādhyāya Verses 78–79, says:
"The Lords of the days are to reckoned in order fourth from Saturn downwards. The Lords of the hours are also to be reckoned commencing from Saturn downwards."
Explanation of the rationale
Assume that the classical ancient planets be revolving round the earth. The planets are arranged in the order from slowest to fastest moving as they appear in the night sky, or equivalently, in the order from furthest to nearest to earth. The planets in this order are Saturn, Jupiter, Mars, Sun, Venus, Mercury and Moon. It is further assumed that a day is divided into 24 equal parts or hora-s. The planets are assigned to the 24 hora-s in the same order as indicated earlier one by one cyclically. On a given day, the cycle of planets will be repeated three times. The planet assigned to the first hora on a given day would be the planet immediately following the planet that was assigned to the 24th hora of the previous day. The name of the week-day on a given day will be the name associated with the planet associated with the first hora of the day. Thus, if the planet associated with the first hora of a day is Sun, the planet associated with the next day would be Moon, the planet associated with the third day would be Mars, and so on. The order of the weekdays thus becomes Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn.
This rationale is reflected in one of the literal meanings of the Sanskrit word vāsara (another term for vāra) which is "relating to or appearing in the morning".
The concept of vāra in India
The rationale behind the naming of the days of a week is certainly not of Indian origin. Also the concept of a seven-day week as a unit of time is not of Indian origin. The system of dividing a day into 24 hora-s is there in India only in the astrological literature. Works on astronomy like Surya-Siddhānta and Āryabhaṭīya do not mention hora as unit of time. In such works, the common practice is to divide day into 60 ghaṭi-s and each ghaṭi into 60 vighaṭi-s. Moreover, no work of the Vedic and the Vedāṅga period mentions it. Further, the word hora is not even of Sanskrit origin. Chaldeans had this unit in use since a long time and they did have a week of seven-days. Vāra-s were known to Chaldeans long before 3800 BCE. It is probably the case that the ancient Indian astronomers and astrologers borrowed the concept of vāra or week from the Chaldeans.
The Atharva Veda contains references to vāra. From evidences obtained from Atharva Jyotiṣa and Yājñavalkya Smṛti, it has been determined that the vāra-s began to be used in a period much earlier than the period when the 12 zodiacal signs began to be used. Thus, in the Indian subcontinent, the use of vara-s predates the use of the rāśi-s. The days of the week may have been introduced in India at about 1000 BCE and they are not more modern than 500 BCE.
The names of the vāra-s
The names of the vāra-s in all of the 22 languages recognized by the Constitution of India are given in the following table. For a longer list, see: Week-days in languages of the Indian subcontinent.
See also
Nakshatra
Tithi
Karaṇa
Nityayoga
Planetary hours
References
Calendars
Units of time
Hindu astronomy
Astronomy in India
History of astronomy | Vāra (astronomy) | [
"Physics",
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"Mathematics"
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"Spacetime",
"Units of measurement"
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77,352,140 | https://en.wikipedia.org/wiki/Break%20room | A break room is a room in a workplace where employees can go during meals and other breaks.
About
Since the 2010s, many workplaces have sought to enhance their employee break rooms by installing micromarkets inside them. Micromarkets provide expanded food options compared to traditional vending machines. During the COVID-19 pandemic, some workplaces began to install self-service kiosks, touch-free coffee machines, and other forms of upgraded technology in their employee break rooms to reduce the transmission of COVID and other diseases.
Many workplaces display employment-related posters and announcements in their break rooms.
The placement of surveillance cameras in workplace break rooms has been controversial. In 2017, a camera was removed from the employee break room of a town hall in Michigan following backlash from workers. In 2001, custodians at a high school in Ohio sued after discovering that a hidden camera had been installed in the break room to monitor them. The workers in Brannen v. Board of Education claimed a violation of their Fourth Amendment rights, but the court ruled that the workers had no reasonable expectation of privacy given that a break room is a public space.
Break room laws and regulations
Australia
Queensland's Workplace Health and Safety Act 1995 required that "A workplace must have a lunch room in or adjacent to the workplace." The law stated that the lunch room must be separate from areas where work is performed and must not be used for any purpose other than lunches and other breaks.
Canada
Prince Edward Island's Occupational Safety and Health Act requires workplaces to have a "Lunch and rest room" that is separate from toilet areas and is equipped with suitable seating and tables.
Nova Scotia's Occupational Health and Safety Act requires workplaces to "provide an enclosed eating area separate from the work area" only when "the possibility of contamination of food from a hazardous substance exists in a work area".
France
In France, workplaces with fewer than 50 workers "must provide employees with a place where they can eat in good health and safety." Companies with more than 50 employees must provide workers with a catering room equipped with seating, a table, drinking water, refrigeration, and food heating appliances.
Germany
German law mandates that all workplaces with more than 10 employees must have a break room. Workplaces with fewer than 10 employees must also have break rooms if necessitated for safety or health reasons. The law stipulates that break rooms must have adequate tables and seating.
Netherlands
In the Netherlands, the Working Conditions Decree mandates that workplaces must have break rooms and, depending on the number of employees, that the break room must be spacious and have tables and chairs.
New Zealand
According to WorkSafe New Zealand, "Workers should have somewhere they can prepare and eat food during breaks", "This area should be kept clean", and "Workers should have a sheltered place to sit during break times." Temperature-controlled break rooms are also required when necessary.
Norway
Norwegian law does not require workplaces to have break rooms, but if a workplace lacks a "satisfactory break room", the worker must be paid for their break.
United States
As federal law does not require work breaks, there is no federal requirement for workplaces to have break rooms. The United States Access Board requires workplaces that do have break rooms to make them accessible to people with disabilities.
The Occupational Safety and Health Administration (OSHA) lists break rooms as an example of a "common area". Common areas are defined as "indoor or outdoor locations under the control of the employer that more than one person may use or where people congregate...". OSHA does not require workplaces to have a break room.
Workplaces are not required to have break rooms in Connecticut and North Carolina.
California Industrial Welfare Commission requires workplaces to have "suitable resting facilities" that are to be located "separate from toilet rooms".
Illinois law requires break rooms only for hotel workers, stating that "Every employer of hotel room attendants shall make available at all times a room on the employer's premises with adequate seating and tables for the purpose of allowing hotel room attendants to enjoy break periods in a clean and comfortable environment. The room shall have clean drinking water provided without charge."
Washington state only requires break rooms at workplaces where workers could be exposed to toxic substances. The law states that "If the workplace exposes employees to injurious dusts or other toxic materials, the employer must provide a separate lunchroom unless it is convenient for employees to lunch away from the premises."
The Texas Department of Licensing and Regulation has stated that where employee break rooms exist, they must be designed in accordance with Texas Accessibility Standards.
See also
Break (work)
Lactation room
Right to sit
Sick leave
References
External links
Workers Must Be Given a Rest Area, Los Angeles Times
Occupational safety and health
Rooms
Working time | Break room | [
"Engineering"
] | 982 | [
"Rooms",
"Architecture"
] |
77,352,288 | https://en.wikipedia.org/wiki/Crawler%20excavator | A crawler excavator, also known as a track-type excavator or tracked excavator, is a type of heavy construction equipment primarily used for excavation and earthmoving tasks. It is characterized by its tracked undercarriage, which provides superior mobility and traction compared to wheeled excavators, especially in soft, uneven, or unstable terrain.
History
The history of crawler excavators can be traced back to the late 19th century, with the invention of the steam shovel in 1796. However, it wasn't until the 1830s that the first patented excavator with a mechanical boom, the Otis steam excavator, was developed. These early excavators were operated using chains or cables and were primarily used in mining and construction projects, such as of the Panama Canal in the early 20th century.
In the late 19th century, the Kilgore Machine Co. in Minneapolis patented an excavator that used a hydraulic system instead of steam power. This marked a significant step in the evolution of excavators, as hydraulic systems provided greater control and efficiency compared to the previous cable-operated designs. Throughout the 20th century, manufacturers continued to refine and improve the hydraulic systems, leading to the development of the first 360-degree rotating excavator, the Bucyrus 120-B, in 1925.
The 1920s saw the emergence of modern crawler excavators, which were mounted on tracks or wheels rather than rails, increasing their mobility and versatility. These excavators were powered by gasoline or diesel engines, further improving their performance and capabilities. The demand for construction equipment, including excavators, increased significantly during World War II, as they were used for tasks such as digging trenches and rebuilding infrastructure.
In the decades following World War II, crawler excavators continued to evolve, with manufacturers introducing a wide range of models and sizes to meet the diverse needs of the construction and mining industries. Technological advancements, such as improved hydraulic systems, more efficient engines, and the addition of various attachments, have further expanded the capabilities of crawler excavators. Today, these machines are widely used in a variety of applications, including digging, material handling, demolition, and forestry work.
Mini-excavators
The 1960s saw the development of mini excavators, which were designed to fit into tight construction sites and urban environments. The YNB 300, developed by Yanmar Construction Company, was the world's first mini excavator. This compact machine was self-propelled and wheeled, making it highly maneuverable and suitable for urban construction projects.
Features
The main components of a crawler excavator include:
Undercarriage: The tracked undercarriage provides excellent stability and mobility on rough or soft ground. The tracks distribute the machine's weight over a larger area, reducing ground pressure and allowing the excavator to traverse soft, muddy, or uneven surfaces that would be impassable for wheeled equipment.
Upperstructure: The rotating upperstructure, or "house", contains the operator's cab, engine, and hydraulic components. This allows the excavator to rotate 360 degrees, providing excellent maneuverability and the ability to dig, load, and place material from a single position.
Boom and Dipper: The boom and dipper (or stick) are the two main structural components that support the bucket and allow for excavation, lifting, and placement of materials.
Bucket: The bucket is the primary tool attached to the end of the dipper. Buckets come in a variety of sizes and shapes to handle different materials and applications, such as general excavation, trenching, demolition, etc.
Applications
Crawler excavators are versatile machines used in a wide range of construction, mining, and infrastructure projects, including:
Digging foundations, trenches, and pits
Loading trucks and hoppers
Demolition and debris removal
Material handling and placement
Landscaping and site preparation
Forestry and land clearing
Dredging and underwater excavation
The tracked undercarriage allows crawler excavators to operate effectively in soft, muddy, or uneven terrain where wheeled excavators would struggle. This makes them well-suited for applications in remote or difficult-to-access areas, as well as in sensitive environments where ground disturbance needs to be minimized.
Configurations
Crawler excavators come in a wide range of sizes, from compact excavators weighing just a few tons up to massive mining-class machines weighing hundreds of tons. The size and power of the excavator is typically selected based on the specific application and job requirements.
Some key size and configuration options for crawler excavators include:
Operating Weight: Ranging from approximately 1 to 800 tons
Engine Power: From less than 20 hp up to 4,500 hp for the largest models
Bucket Capacity: From less than 1 cubic yard to over 52 cubic yards
Boom Length: Typically 20 to 425 feet, depending on the excavator size
Tracks: Steel, rubber, or a combination for different terrains and applications
Crawler excavators are manufactured by a variety of heavy equipment companies, including Caterpillar, Komatsu, Hitachi, Volvo, Liebherr, and many others. The choice of brand and model is often based on factors such as performance, reliability, operating costs, and dealer/service support in the local market.
References
Excavators
Construction equipment
Engineering vehicles | Crawler excavator | [
"Engineering"
] | 1,111 | [
"Construction",
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77,353,600 | https://en.wikipedia.org/wiki/LAMA2%20related%20congenital%20muscular%20dystrophy | LAMA2 muscular dystrophy (LAMA2-MD) is a genetically determined muscle disease caused by pathogenic mutations in the LAMA2 gene. It is a subtype of a larger group of genetic muscle diseases known collectively as congenital muscular dystrophies. The clinical presentation of LAMA2-MD varies according to the age at presentation. The severe forms present at birth and are known as early onset LAMA2 congenital muscular dystrophy type 1A or MDC1A. The mild forms are known as late onset LAMA2 muscular dystrophy or late onset LAMA2-MD. The nomenclature LGMDR23 can be used interchangeably with late onset LAMA2-MD.
Suggestive clinical features include, muscular hyperlaxity or hypotonia, growth retardation progressive spine and joint contractures, and cardiac and respiratory failure.
For consensus, generally, the term congenital muscular dystrophy refers to a diverse group of childhood onset muscle diseases -usually occurring the first two years of life- and mostly inherited through an autosomal recessive mode. Congenital muscular dystrophies have known phenotype-genotype profiles and produce muscle degenerative pathology.
Symptoms and signs
There are two types of LAMA2 muscular dystrophy (LAMA2-MD). The first type is the congenital type known as early onset LAMA2 congenital muscular dystrophy type 1A or MDC1A. It presents at birth and has a relatively severe clinical presentation. Characteristically it manifests in muscle weakness, hyperlaxity or hypotonia, respiratory difficulties and developmental delay.
The second type is the late onset LAMA2 muscular dystrophy or late onset LAMA2-MD. The age of presentation of late onset LAMA2-MD ranges from early childhood to adulthood. It usually has a mild clinical presentation in the form of progressive spine and joint contractures, and cardiac and respiratory failure.
Musculoskeletal manifestations
Delayed development of motor milestones as loss of ambulatory capacity is usually more severe in the congenital type 1A or MDC1A. Skeletal muscle weakness is a characteristic feature. It more evident in the proximal muscles of the extremities. Facial and neck weakness have also been reported. Scoliosis is a side curvature or abnormal deviation of the spine with an element of rotation. Scoliosis is usually rigid and progressive. It may be accompanied by lordosis.
The clinical orthopedic features of congenital type 1A (MDC1A) in terms of type, distribution, laterality, deformity progression, chronological order of muscle and joint involvement etc., have shown a fairly characteristic pattern. This is important to the differential diagnosis of LAMA2-MD and other subtypes of congenital muscular dystrophies among others. LAMA2-MD especially MDC1A, usually manifests in progressive contractures of large joints like knees, ankles, elbow and hips. Contractures tend to be bilateral. That is involving both the left and right sides. Observing the chronological order of development of joint contractures, namely early versus late in the disease course, could offer differential diagnostic clues for congenital muscular dystrophies as MDC1A, LMNA-Related muscular dystrophy among other genetic muscle diseases. Of note, any unique clinical orthopedic features of LAMA2-MD should be put into context with the other clinical features, characteristic brain and muscle imaging, muscle immunostaining and genetic testing findings. An International retrospective early natural history study of LAMA2-MD proposed a classification based on motor or ambulatory capacity in which patients who attain the ability to sit and remain seated are classified as LAMA2-MD1 or LAMA2-RD1 and those who attain the ability to walk independently are classified as LAMA2-MD2 or LAMA2-RD2. A study on a large series LAMA2-MD patients showed that bone mineral density was reduced in all adults and most children. Fragility fractures were reported occasionally.
Respiratory insufficiency
Respiratory insufficiency can occur in both types of LAMA2-MD. Respiratory tract infections are a cause of death in the congenital type 1A or MDC1A.
Cardiac manifestations
Cardiac involvement in LAMA2-MD may manifest in dilated cardiomyopathy and systolic dysfunction. Cardiac screening and surveillance are important in LAMA2-MD. This is aimed at timely diagnosis and management of subclinical cardiac involvement.
Cerebral manifestations
Epilepsy is a fairly common manifestation of both types of LAMA2-MD. However, the age at occurrence of first epileptic fit is earlier in the congenital type 1A or MDC1A. Screening for epilepsy should be included in the workup. Intelligence is usually normal. Epilepsy and intellectual disability were associated with motor dysfunction namely inability to sit and/or walk. Epilepsy and to a lesser extent intellectual disability were also strongly correlated to cortical abnormalities on brain MRI.
Cause
LAMA2-MD is caused by pathogenic variants or mutations in the LAMA2 gene that encodes alpha2 chain of laminin-211 or laminin-alpha2, previously known as laminin type 2 or merosin. laminin-211 is important to the function and integrity of the sarcolemma of muscle fibers. laminin-alpha2 is also present in extra-muscular locations as the central and peripheral nervous system. Pathogenic variants of the LAMA2 gene which lead to loss of function are accompanied by complete deficiency of laminin-alpha2 (merosin) and result in a severe clinical picture or phenotype namely early onset MDC1A. Pathogenic variants of the LAMA2 gene accompanied by partial deficiency of laminin-alpha2 result in a milder clinical picture namely late onset LAMA2 muscular dystrophy or late onset LAMA2-MD. The disease is inherited through an autosomal recessive mode.
Diagnosis
Correlating the characteristic clinical picture with the specific imaging, laboratory and muscle biopsy findings is essential to the diagnosis of LAMA2-MD. The presence of pathogenic variants in LAMA2 gene by Genetic testing, -DNA testing- of the affected individual confirms the diagnosis of LAMA2-MD.
Brain MRI
Abnormal white matter signals in Brain MRI is a near-universal sign in patients with LAMA2-MD. These white matter abnormalities appear as hyperintense signals on T2-weighted and FLAIR brain MRI images especially in locations that are originally myelinated in the immature brain as the periventricular area. Occasional MRI abnormalities include cortical malformations as polymicrogyria, lissencephaly, pachygyria. In LAMA2-MD there seems to be a directly proportional relationship between the magnitude of white mater and cortical abnormalities on brain MRI and the degree of motor dysfunction in terms of the ability to sit and walk.
Whole body muscle MRI
Muscle MRI especially Whole-body muscle MRI can provide important diagnostic clues. Some studies have shown a reasonably characteristic pattern of muscle involvement on whole-body muscle MRI in LAMA2-MD patients. This relates to muscles or group of muscles involvement versus sparing. For example, sparing of the gracilis, sartorius muscles, and the adductor longus muscle has been linked to LAMA2-MD. On the other hand, studies showed a specific predilection to involve the gluteus maximus and anterior thigh muscles, adductor magnus muscle, serratus anterior muscle in LAMA2-MD, and so forth. Abnormal muscle texture or geometry on muscle MRI as presence of granular pattern of involvement in a muscle has been suggested to be a diagnostic clue. Similarly, a homogenous pattern of involvement of group of muscle e.g., anterior compartment of thigh, could be used to support diagnosis. Homogenous pattern refers to involvement of all individual muscles of a muscle compartment to the same extent. Moreover, Whole body muscle MRI could be indicative of clinical disease severity and duration of LAMA2-MD. It can also help establish phenotype genotype correlations
However, these muscle MRI features may overlap with other subtypes of congenital muscular dystrophy. Additionally, some inconsistencies between the above muscle imaging studies can be noted. Thus, more longitudinal studies with larger cohorts and standardized methodologies are needed to arrive at a more uniform and consistent muscle MRI signature in LAMA2-MD. It is therefore paramount to correlate muscle imaging findings with clinical, neuro-imaging, laboratory and genetic testing findings.
Muscle biopsy or immunostaining
There is an inversely proportional relationship between the quantity of laminin alpha2 (merosin) found on immunohistochemistry and disease severity. That means, a more marked degree of laminin-alpha2 deficiency e.g., total or near-total deficiency, is associated with more pronounced muscle degenerative pathology as myofibrosis, necrosis and fiber size variation. This is also associated with a more severe clinical picture. A less marked degree of laminin-alpha2 (merosin) deficiency -residual staining- is associated with a less pronounced muscle degenerative pathology and a milder clinical picture. Generally, congenital muscular dystrophy type 1A or MDC1A is known to have a severer clinical picture than late onset LAMA2-MD. However, the degree of deficiency of laminin alpha2 (merosin) on immunohistochemistry in MDC1A can varies. Clinical disease severity associated with total laminin-alpha2 (merosin) deficiency usually manifests itself in early onset of symptoms, loss of ambulatory capacity and respiratory difficulties.
Treatment
Targeted therapies
There is no definite cure available for LAMA2-MD. However, preclinical studies on experimental animal models of Laminin alpha-2 chain deficient congenital muscular dystrophy are showing favorable yet early results. Generally, these preclinical studies are geared toward investigating the various factors behind disease initiation and progression, and exploration of potential ameliorating or curative therapies. Preclinical studies focus on combating substances that regulate and promote muscle fibrosis in the pathogenesis of LAMA2-MD e.g., TGF-β. This may reduce muscle fibrosis and enhance healthy muscle architecture subsequently. Alternatively, preclinical studies can be geared toward enhancing proteins that are involved in muscle regeneration. Laminin alpha2 (Laminin-211) and laminin-221 complex are an important molecule for muscle cell receptors namely integrin-α7β1 and α-dystroglycan. In LAMA2-CMD the laminin alpha2 deficiency results in malfunctioning or down regulation of integrin-α7β1 and α-dystroglycan. This disrupts the proper linkage between the basal lamina and muscle cell membrane. Consequently, the contractile mechanism is disrupted. Integrin-α7β1 is important to satellite cell function, and myoblast adhesion and viability. Thusly, integrin-α7β1is an important contributor to skeletal muscle regeneration. Cell therapies that compensate for the deficiency or down regulation of integrin-α7β1 have the potential to delay or control the muscle degenerative process and preserve muscle architecture in LAMA2-CMD patients. Additionally, the use of laminin-111 treatment in experimental mouse models of LAMA2-CMD has showed satisfactory results in terms of increase in life expectancy muscle function and regeneration.
Supportive treatment
Currently, treatment is mainly supportive and palliative. It is directed at anticipating and preventing or alleviating the systemic complications associated disease progression. This refers to management of respiratory, cardiac, orthopedic and rehabilitative, central nervous system e.g., epilepsy, gastrointestinal and so forth.
Prognosis
Prognosis is dependent on the subtype of LAMA2-MD. Nearly all children with early onset or congenital muscular dystrophy type 1A (MDC1A) are unable to walk independently. Nevertheless, children with MDC1A are usually able to sit. Contrastingly, patients with late onset LAMA2-MD are usually able to walk independently. Of note, in both types of LAMA2-MD developmental motor milestones are delayed.
Additionally, the prognosis is dependent on the degree of surveillance and supportive care that patients receive in regard to the multisystem manifestations and potential complications of LAMA2-MD. This refers to prompt and timely management of orthopedic, cardiopulmonary, epilepsy and gastrointestinal systems among others. The multisystem manifestations may affect the quality of life of patients with LAMA2-MD.
Epidemiology
It is estimated that congenital muscular dystrophies occur in between 0.563 per 100,000 (in Italy) and 2.5 per 100,000 (in western Sweden). The prevalence data on congenital muscular dystrophy type 1A (MDC1A) varies by geographic location or population. Example, in the United Kingdom MDC1A constituted about 37% of all congenital muscular dystrophy subtypes namely the most common subtype. In Qatar, MDC1A constituted 48% of congenital muscular dystrophy subtypes with estimated a point prevalence of 0.8 in 100.000 in a patient cohort from the Gulf and Middle East. Contrastingly, in Australia it constituted 16% of all congenital muscular dystrophy subtypes namely the third most common subtype. A scoping review on clinical orthopedic manifestations of congenital muscular dystrophy subtypes reported that the most common subtype was MDC1A accounting for 37% of the total study sample.
See also
Rigid spine syndrome
Ullrich congenital muscular dystrophy
Bethlem myopathy
LMNA-related congenital muscular dystrophy
Congenital myopathy
References
External links
LAMA2 gene: MedlinePlus Genetics
Cure CMD | Congenital Muscular Dystrophy
Congenital Muscular Dystrophy (CMD) - Diseases
Congenital Muscular Dystrophy - Symptoms, Causes, Treatment | NORD
LAMA2 laminin subunit alpha 2 [Homo sapiens (human) - Gene - NCBI]
Medicine | LAMA2 related congenital muscular dystrophy | [
"Biology"
] | 2,986 | [
"Medicine"
] |
77,354,265 | https://en.wikipedia.org/wiki/Samsung%20Galaxy%20Ring | The Samsung Galaxy Ring is a smart ring developed by Samsung Electronics. It was released on July 10, 2024, alongside the Galaxy Watch 7 and 7 Ultra. It is the first smart ring with biometric health monitoring. The ring launched with a price at $399.99.
Specifications
Hardware
The Samsung Galaxy Ring is 7.0mm by 2.6 mm in dimensions and weighs between 2.3 and 3 grams, depending on ring size. The ring has 8 MB of RAM and a battery between 18 and 23.5mAh (depending on ring size) which lasts up to 7 days. The ring is equipped with an accelerometer, PPG and skin temperature sensors. The ring uses BLE 5.4 connectivity. The ring has been IP68 and 10ATM rated. It is compatible with Android phones operated by Android 11 or above and have Samsung Health app installed. The ring comes with three color variations which are Titanium Black, Titanium Silver, Titanium Gold.
See Also
Oura Ring
References
Samsung Galaxy
Activity trackers
Products introduced in 2024 | Samsung Galaxy Ring | [
"Technology"
] | 216 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
77,356,603 | https://en.wikipedia.org/wiki/Caloboletus%20marshii | Caloboletus marshii, commonly known as Ben's bitter bolete, is a species of mushroom in the family Boletaceae. It is not poisonous, but it is too bitter to eat. It turns blue when cut or bruised, and it grows under live oak.
Taxonomy
Caloboletus marshii was first unofficially described by David Arora as Boletus "marshii" in his book Mushrooms Demystified, which was first published in 1979 and later revised in 1986. In 2014, Jonathan L. Frank formally described the species as Caloboletus marshii.
Description
The cap of Caloboletus marshii is about 2-6 inches (6-15 cm) across, and the stipe is about 1-4 inches (3-10 cm) long and 0.7-4 inches (3-10 cm) wide. The pore surface and the flesh are yellow, and quickly turn blue when bruised or cut.
Similar species
Caloboletus marshii can be confused with the brown butter bolete, Butryiboletus persolidus. It can also be confused with the white king bolete, Boletus barrowsii, which doesn't bruise blue as much as Caloboletus marshii.
Habitat and ecology
Caloboletus marshii is a mycorrhizal fungus that grows under live oaks in California, Oregon, and Washington. It fruits in late summer and fall, often before the rains come. It is rarely found fruiting in November.
Edibility and discovery
Caloboletus marshii is inedible due to its extremely bitter taste. However, this didn't stop a man named Ben Marsh from repeatedly trying to make it edible. This brought the mushroom to David Arora's attention, and he named it after Ben Marsh.
See also
List of North American Boletes
References
marshii
Fungus species
Inedible fungi
Fungi described in the 20th century
Fungi of California | Caloboletus marshii | [
"Biology"
] | 400 | [
"Fungi",
"Fungus species"
] |
77,358,029 | https://en.wikipedia.org/wiki/Arnold%20Caplan | Arnold Caplan (1942–2024) was a scientist and professor at Case Western Reserve University known for being the father of mesenchymal stem cells (MSCs). His initial work focused on the “Mesengenic process” whereby MSC’s could be preferentially differentiated into the numerous tissues of the mesodermal lineage
Career
He joined Case Western in 1969.
He founded Osiris Therapeutics in 1992.
He has said "by calling them “Mesenchymal Stem Cells,” we are misrepresenting what the cells’ true functions are in the body; instead, he proposes that these cells be renamed “Medicinal Signaling Cells,” to better reflect their main functions in the body: an intelligent source of therapeutic signals for the body to repair and regenerate."
References
1942 births
2024 deaths
Case Western Reserve University faculty
Place of birth missing | Arnold Caplan | [
"Biology"
] | 179 | [
"Stem cell researchers",
"Stem cell research"
] |
77,359,208 | https://en.wikipedia.org/wiki/Asplenium%20aethiopicum | Asplenium aethiopicum is a lithophytic or sometimes epiphytic species of fern found in Southern and tropical Africa, tropical America, Asia and Australia. It is listed as critically endangered in Victoria, Australia. It is considered exotic in New Zealand.
Taxonomy
Asplenium aethiopicum was originally published under the name Trichomanes aethiopicum by Nicolaas Laurens Burman in 1768. In 1935 Alfred Becherer moved this taxon to the genus Asplenium creating the name Asplenium aethiopicum.
References
aethiopicum
Flora of South Africa
Flora of Zimbabwe
Flora of Western Australia
Flora of Queensland
Flora of New South Wales
Flora of Victoria (state)
Flora of New Guinea
Flora of India
Flora of Saudi Arabia
Flora of Zambia
Flora of the Democratic Republic of the Congo
Flora of Angola
Flora of Burundi
Flora of the Central African Republic
Flora of Eritrea
Flora of Ethiopia
Flora of Fiji
Plants described in 1935
Lithophytes
Epiphytes | Asplenium aethiopicum | [
"Biology"
] | 200 | [
"Lithophytes",
"Plants"
] |
77,360,869 | https://en.wikipedia.org/wiki/Tasmanite%20%28mineral%29 | Tasmanite, or Tasmanian amber (in the original sense of the word: “discovered in Tasmania”) — a rare regional mineraloid, a brownish-reddish fossilized organic resin from the island of Tasmania, formed in some deposits of the parent rock (tasmanite shale) and known by the same name: tasmanite.
Found in bituminized shales on the banks of the Mersey River (northern Tasmania), this mineral was examined and described in 1865 by Professor A. J. Church. Meanwhile, translucent tasmanite is not formed everywhere where there are deposits of the sedimentary rock of the same name, but only in some layers.
Over the next century and a half, almost no new evidence appeared about Tasmanian amber.
Origin and genesis
The parent rock, also called Tasmanite, is itself a special type of sedimentary rock of organic origin, common not only in Tasmania or Australia, but also throughout the globe. Tasmanite as a rock is a typical oil shale, - with a very high carbon content, formed from Late Permian and Carboniferous deposits of unicellular algae. In appearance, Tasmanite is a fossilized amorphous mass containing large quantities of remains of spores (cysts) and pollen. In its pure form, tasmanite consists almost entirely of flattened and compressed microspore shells. The initial forming substance is necroma of brackish-water seaweeds from the genus Tasmanites (; Newton, 1875). The color of the differences is always dark, mixed, the tonality varies depending on the location in the range from gray-brown to black; Due to the high spore content, most samples appear to be covered in yellow pollen. The same picture is visible on the tasmanite fracture.
Tasmanite is distinguished by a very high homogeneity of composition; it consists almost exclusively of organic matter, compressed shells of microspores of algae from the genus Tasmanites and, thus, can be classified as a standard liptobiolite. The carbon content in pure samples fluctuates around 81% with a small error. After burning Tasmanite, a small amount of white ash remains, retaining the shape of the original sample. Tasmanites throughout the world are among the richest oil source rocks; the conversion factor of organic matter into oil is about 78%.
Tasmanite rarely forms independent accumulations; for the most part it accompanies deposits of various coals of autochthonous origin, that is, coals that occur at the site of deposition of organic matter that gave them their origin. The thickness of Tasmanite layers, as a rule, does not exceed 1.5 meters, moreover, they are not continuous, but separated by a layer of sedimentary clay. In one of these layers in the vicinity of the Mersey River, Professor A. J. Church discovered in 1864 translucent mineral formations, their appearance reminiscent of dark reddish-brown amber.
The discovered layer of Tasmanite shale, according to the researcher, was significantly different from other deposits that he had to examine. Fossil resin of a brownish-reddish color and gelified appearance was contained here not just in the form of inclusions, but in very large quantities, literally penetrating the entire layer, which was especially noticeable in the section.
Translucent reddish-brown or brown varieties grown into the Tasmanite shale ultimately accounted for up to 40% of the main rock and had the appearance of narrow scaly lenses, difficult to separate from the main rock. It is also known that this deposit itself had a small size and was located near the floodplain of the River Mersey. Professor Church did not indicate a more precise location.
Properties and composition
The organic mineraloid, described under the name Tasmanite, was translucent even when not polished, standing out sharply against the background of the main rock. It had a reddish-brown or reddish-brown color and a waxy sheen. The hardness on the Mohs scale was approximately 2, and the density was significantly higher than that of amber, hovering around 1.8. The fracture of the mineral was conchoidal. Birefringence, dispersion and distinct pleochroism were absent.
Professor A. J. Church also investigated the chemical composition, within the limits of his capabilities. As it turned out, according to the results of the research, when heated, the mineral easily melted, emitting a strong odor, probably oil-like. Tasmanite also dissolved slowly in hydrochloric acid, ethyl alcohol and turpentine. According to analyzes of several samples, the mineral contained 79.34% carbon, 10.41% hydrogen, 4.93% oxygen and 5.32% sulfur — as you can see, the given figures add up to 100%. From here the approximate formula of tasmanite was derived: C40H124O2S. In addition to the high content of sulfur (organic sulfides), attention is drawn to the relatively high specific gravity of this substance.
Probably, the inclusions of resinous translucent tasmanite in the bulk of the Tasmanite schist were not necessarily associated with the presence of any other resin-containing plant remains, except for the rock-forming algae of the genus Tasmanites. Most likely, the effect of compaction and clarification of the mineral had a connection with deeper metamorphism of the rock in this particular place. As the German petrographer noted in a comparative study at the end of the 1960s, the appearance of a reddish tint for liptobiolites formed by this alga is characteristic of the fatty carbon stage. Microscopic studies of thin sections of two Tasmanites from different deposits showed that Alaskan Tasmanites, which have a reddish sheen, are metamorphosed to a much greater extent than Australian ones, which have a golden-yellow color of weakly "carbonized" .
Taking into account all known data, it would be most accurate to define “Tasmanian amber” as a compacted and partially purified infiltrate formed as a result of the metamorphism of the Late Carboniferous shale of the same name.
There is also no doubt that the external similarity is not accidental: amber and tasmanite belong to the same group of liptobilites – fossil coals enriched with the most decomposition-resistant components of plant matter: waxes, fossil resins, and other similar natural compounds. In addition to amber and tasmanite, representatives of this group of are, for example, the organic mineral fichtelite.
In the old mineralogical literature, a large number of specific names were proposed for resins of various origins <... for example>, tasmanite is the name given to the compacted Late Carboniferous infiltrates of Tasmania...
— Vladimir Zherikhin, "Introduction to paleoentomology", 2008
On the other hand, the trivial name "Tasmanian amber" found in the literature should not be perceived as anything other than a mineralogical metaphor that simplifies the outside perception of a little-known object. Fossil resins in general are often called amber, since this mineraloid is undoubtedly the most popular and well known among other stones of organic origin. Fossil resins other than true amber are sometimes also classified as retinites or resinites, but these terms are not clearly defined. It is obvious that tasmanite can appear as a special regional liptobiolite among the specific names of natural resins of various origins adopted in the old mineralogical literature. These undoubtedly include simetite (Sicilian amber), romanite (Romanian amber), chemavinite and cedarite (Canadian chalk resins) and many others that have the status of local "amber".
References
See also
Tasmanite
Cannel coal
Kerosene shale
Amber
Copal
List of types of amber
Petrified wood
Rocks
Amber
Geology of Tasmania
Mining in Tasmania
Fossil resins
Amorphous solids | Tasmanite (mineral) | [
"Physics"
] | 1,633 | [
"Amber",
"Unsolved problems in physics",
"Physical objects",
"Rocks",
"Amorphous solids",
"Matter"
] |
77,361,091 | https://en.wikipedia.org/wiki/Electronic%20mail%20game | In game theory, the electronic mail game is an example of an "almost common knowledge" incomplete information game. It illustrates the apparently paradoxical situation where arbitrarily close approximations to common knowledge lead to very different strategical implications from that of perfect common knowledge. Intuitively, it shows that arbitrarily long but finite chains of "I know that you know that I know that you know..." are fundamentally different from infinite ones.
It was first introduced by Ariel Rubinstein in 1989.
The game
Setup
The electronic mail game is a coordination game of incomplete information. Players 1 (she) and 2 (he) can choose between actions and . There are two states of the world and , which happen with respective probabilities and , with . The payoffs for each action profile in each of those states are:
where . Players would like to coordinate to play in state of the world , and to play in . If they coordinate in the wrong state, they only get payoff; but if they choose different actions, the player who chose gets a negative payoff of .
Player 1 knows the true state of nature, whereas Player 2 does not. Without communicating, the highest expected payoff they can achieve is , by always choosing . If the state of the world were common knowledge, both players would be able to achieve payoff .
Email communication
Now assume that the players communicate via emails. Once Player 1 discovers the state of nature, her computer automatically sends an email to Player 2 informing him of the true state; Player 2's computer then automatically replies with a confirmation that he received the information; Player 1's computer then automatically replies with a confirmation that she received the information that he received the information, and so on. This mimics the idea of a "I know that you know that I know that you know..." chain.
However, there is an arbitrarily small probability that some technical failure will happen and one of those emails will not arrive at its destination, after which communication will cease. If that happens, the last player to send the message does not know if 1) the other player did not get the last message, or 2) the other player got the last message, but could not send the confirmation email due to the technical failure.
Types and strategies
Let be the number of messages that were sent by Player 's computer — since that information is only observed by Player , we can think of as their Harsanyi type. In terms of choice, players only observe and then must choose an action . A strategy in the electronic mail game is thus defined as a function from to .
The distribution of types is given by the following probabilities :
: the true state is and no email is sent
: the true state is and the failure happens in Player 2's computer after Player 1 sent emails
: the true state is and the failure happens in Player 1's computer after Player 1 sent emails
Equilibrium
The equilibrium concept to be used is that of a Bayesian Nash Equilibrium (BNE). Rubinstein showed that, no matter how small the chance of failure and no matter how many confirmation emails were sent, both players always choose to play , even if they know that the state of nature is .
Proposition: There is only one BNE where Player 1 plays when the state of nature is . In this equilibrium, both players play , independently of their types.
The result is counterintuitive, since both know that the true state is , and they can have arbitrarily precise knowledge of "knowing that the other player knows that they know that the other player knows..." that the state is . Still, since this chain of information eventually stops, their equilibrium best response still is to always play .
References
Game theory
Cooperative games | Electronic mail game | [
"Mathematics"
] | 767 | [
"Game theory",
"Cooperative games"
] |
77,361,219 | https://en.wikipedia.org/wiki/Normalized%20solution%20%28mathematics%29 | In mathematics, a normalized solution to an ordinary or partial differential equation is a solution with prescribed norm, that is, a solution which satisfies a condition like In this article, the normalized solution is introduced by using the nonlinear Schrödinger equation. The nonlinear Schrödinger equation (NLSE) is a fundamental equation in quantum mechanics and other various fields of physics, describing the evolution of complex wave functions. In Quantum Physics, normalization means that the total probability of finding a quantum particle anywhere in the universe is unity.
Definition and variational framework
In order to illustrate this concept, consider the following nonlinear Schrödinger equation with prescribed norm:
where is a Laplacian operator, is a Lagrange multiplier and is a nonlinearity. If we want to find a normalized solution to the equation, we need to consider the following functional: Let be defined by
with the constraint
where is the Hilbert space and is the primitive of .
A common method of finding normalized solutions is through variational methods, i.e., finding the maxima and minima of the corresponding functional with the prescribed norm. Thus, we can find the weak solution of the equation. Moreover, if it satisfies the constraint, it's a normalized solution.
A simple example on Euclidean space
On a Euclidean space , we define a function
with the constraint .
By direct calculation, it is not difficult to conclude that the constrained maximum is , with solutions and , while the constrained minimum is , with solutions and .
History
The exploration of normalized solutions for the nonlinear Schrödinger equation can be traced back to the study of standing wave solutions with prescribed -norm. Jürgen Moser firstly introduced the concept of normalized solutions in the study of regularity properties of solutions to elliptic partial differential equations (elliptic PDEs). Specifically, he used normalized sequences of functions to prove regularity results for solutions of elliptic equations, which was a significant contribution to the field. Inequalities developed by Emilio Gagliardo and Louis Nirenberg played a crucial role in the study of PDE solutions in spaces. These inequalities provided important tools and background for defining and understanding normalized solutions.
For the variational problem, early foundational work in this area includes the concentration-compactness principle introduced by Pierre-Louis Lions in 1984, which provided essential techniques for solving these problems.
For variational problems with prescribed mass, several methods commonly used to deal with unconstrained variational problems are no longer available. At the same time, a new critical exponent appeared, the -critical exponent. From the Gagliardo-Nirenberg inequality, we can find that the nonlinearity satisfying -subcritical or critical or supercritical leads to a different geometry for functional. In the case the functional is bounded below, i.e., subcritical case, the earliest result on this problem was obtained by Charles-Alexander Stuart using bifurcation methods to demonstrate the existence of solutions. Later, Thierry Cazenave and Pierre-Louis Lions obtained existence results using minimization methods. Then, Masataka Shibata considered Schrödinger equations with a general nonlinear term.
In the case the functional is not bounded below, i.e., supcritical case, some new difficulties arise. Firstly, since is unknown, it is impossible to construct the corresponding Nehari manifold. Secondly, it is not easy to obtain the boundedness of the Palais-Smale sequence. Furthermore, verifying the compactness of the Palais-Smale sequence is challenging because the embedding is not compact. In 1997, Louis Jeanjean using the following transform:
Thus, one has the following functional:
Then,
which corresponds exactly to the Pokhozhaev's identity of equation. Jeanjean used this additional condition to ensure the boundedness of the Palais-Smale sequence, thereby overcoming the difficulties mentioned earlier. As the first method to address the issue of normalized solutions in unbounded functional, Jeanjean's approach has become a common method for handling such problems and has been imitated and developed by subsequent researchers.
In the following decades, researchers expanded on these foundational results. Thomas Bartsch and Sébastien de Valeriola investigate the existence of multiple normalized solutions to nonlinear Schrödinger equations. The authors focus on finding solutions that satisfy a prescribed norm constraint. Recent advancements include the study of normalized ground states for NLS equations with combined nonlinearities by Nicola Soave in 2020, who examined both subcritical and critical cases. This research highlighted the intricate balance between different types of nonlinearities and their impact on the existence and multiplicity of solutions.
In bounded domain, the situation is very different. Let's define where . Refer to Pokhozhaev's identity,
The boundary term will make it impossible to apply Jeanjean's method. This has led many scholars to explore the problem of normalized solutions on bounded domains in recent years. In addition, there have been a number of interesting results in recent years about normalized solutions in Schrödinger system, Choquard equation, or Dirac equation.
Some extended concepts
Mass critical, mass subcritical, mass supcritical
Let's consider the nonlinear term to be homogeneous, that is, let's define where . Refer to Gagliardo-Nirenberg inequality: define
then there exists a constant such that for any , the following inequality holds:
Thus, there's a concept of mass critical exponent,
From this, we can get different concepts about mass subcritical as well as mass supercritical. It is also useful to get whether the functional is bounded below or not.
Palais-Smale sequence
Let be a Banach space and be a functional. A sequence is called a Palais-Smale sequence for at the level if it satisfies the following conditions:
1. Energy Bound: .
2. Gradient Condition: as for some .
Here, denotes the Fréchet derivative of , and denotes the inner product in . Palais-Smale sequence named after Richard Palais and Stephen Smale.
See also
Standing wave
Sobolev inequality
Palais–Smale compactness condition
Variational principle
Schrödinger picture
Mathematical formulation of quantum mechanics
Relation between Schrödinger's equation and the path integral formulation of quantum mechanics
References
Further reading
Quantum mechanics
Partial differential equations
Calculus of variations | Normalized solution (mathematics) | [
"Physics"
] | 1,307 | [
"Theoretical physics",
"Quantum mechanics"
] |
77,361,387 | https://en.wikipedia.org/wiki/Patch%20management | Patch management is concerned with the identification, acquisition, distribution, and installation of patches to systems. Proper patch management can be a net productivity boost for the organization. Patches can be used to defend against and eliminate potential vulnerabilities of a system, so that no threats may exploit them. Problems can arise during patch management, including buggy patches that either fail to fix their problem or introduce new issues. Patch management tools help orchestrate all of the procedures involved in patch management.
Description
Patch management is defined as a sub-practice of various disciplines including vulnerability management (part of security management), lifecycle management (with further possible sub-classification into application lifecycle management and release management), change management, and systems management. The practice is broadly concerned with the identification, acquisition, distribution, and installation of patches to systems. Some definitions of patch management are as a software-level practice, while others are as a systems-level process: software, drivers, and firmware.
Cost–benefit analysis
While reserving time for patching takes up enterprise resources, there are balancing factors which can make proper patch management into a net productivity boost for the organization. Up-to-date systems often perform more efficiently, less expensively, with less errors, less security risks, and better user workflow. Additionally, compliance with changing local and federal regulations are more likely to be satisfied.
Relation to security management
Patches can be used to defend against and eliminate potential vulnerabilities of a system, so that no threats may exploit them; therefore, patch management can be considered a sub-discipline of vulnerability management. Every patchable device in a system presents an attack surface that must be secured.
Challenges
There are a multitude of problems that can arise during patch management. A common issue is buggy patches, which either fail to fix their problem or introduce new issues. Another issue is deployment synchronization, since various subsystems may receive instructions to update at different times. Similarly, the difficulty of patch management across many devices may grow at an uncontrollable rate depending on organizational size.
One prominent demonstration of the challenges facing proper patch management was the buggy Falcon Sensor patch by CrowdStrike which caused one of the worst IT outages of all time.
Implementations
A patch management tool (alternatively patch manager, patch management system, patch management software, or centralized patch management) help orchestrate all of the procedures involved in patch management. Tools can be in-house (applied locally by local administrators), or external, as with managed service providers (applied externally by a provider).
Patch management software
Intel Active Management Technology, used with Intel vPro technologies, has features like scheduling, upgrade verification, and remote management; implementing patches along with unified endpoint management.
Windows Update for Business, System Center Configuration Manager, and Windows Server Update Services offer control over patch deployment, with features enabling testing, scheduling updates, and setting custom configurations on Windows platforms.
Managed service providers
ManageEngine Patch Manager
SolarWinds Patch Manager
Automox
Atera
Kaseya VSA
References
Information technology management
Configuration management
System administration | Patch management | [
"Technology",
"Engineering"
] | 624 | [
"Systems engineering",
"Information technology management",
"Configuration management",
"System administration",
"Information systems",
"Information technology"
] |
69,864,361 | https://en.wikipedia.org/wiki/Aging%20Research%20and%20Drug%20Discovery | Aging Research and Drug Discovery (ARDD) is a non-profit conference which is organized by University of Copenhagen and Columbia University every year at University of Copenhagen.
History
The first ARDD conference was held in 2014 at Basel, Switzerland. Then, this conference was known as Aging Forum and it was a part of MipTec and Basel Life Congresses. The conference was intended to bring together the Pharmaceutical industry, leading academics, Investors and Startups.
References
Life extension organizations
Drug discovery
Columbia University
University of Copenhagen | Aging Research and Drug Discovery | [
"Chemistry",
"Biology"
] | 102 | [
"Life sciences industry",
"Medicinal chemistry",
"Drug discovery"
] |
69,866,611 | https://en.wikipedia.org/wiki/Adaptive%20biasing | In magnetic tape recording, adaptive biasing is the technique of continuously varying the bias current to a recording head in accordance with the level of high-frequency audio signals. With adaptive biasing, high levels of high-frequency audio signals cause a proportionate decrease in bias current using either feedforward or preferably a negative feedback control system. Compared with the use of fixed bias current, adaptive biasing provides a higher maximum output level and higher dynamic range at the upper end of the audible spectrum and to a lesser extent, mid-range frequencies. The effect of adaptive biasing is most pronounced in compact cassette and low-speed reel-to-reel media. The first commercial implementation, the feedforward system Dolby HX was developed by Dolby Laboratories by 1979 and was rejected by the industry. The subsequent negative-feedback system Dolby HX Pro was developed by Bang & Olufsen and marketed by Dolby, and became the de facto standard of the consumer high fidelity industry in the mid-1980s.
Fixed and adaptive biasing
Tape bias is a strong, high-frequency, alternating current that is fed to a tape recording head along with the audio signal with the purpose of making more linear the inherently non-linear response of the magnetic particles in the tape's magnetic coating. The frequency of the bias signal in consumer cassette decks is usually fixed at between 80 and 100 kHz. The quality of the bias signal is critical because noise, hum and direct current in the bias severely degrade audio fidelity. The level of the bias signal defines the slope and shape of the resulting magnetization curve.
The optimal bias level for each tape formulation is a compromise between maximum output levels, noise, distortion and frequency response. Nominal bias, corresponding to maximum sensitivity and/or maximum output at 10 kHz, is less desirable for mid-range frequencies. Over-biasing is better suited for mid-range and low frequencies but it reduces tape sensitivity at higher frequencies and degrades the signal-to-noise ratio. As a side benefit, optimum bias improves the response to tape dropouts because stronger magnetic fields penetrate more deeply into the magnetic coating. Under-biasing causes excessive distortion and modulation noise, and raises the susceptibility to dropouts, and is thus unwanted. In practice, tape is always slightly over biased; the optimal bias current is set at two or three decibels (dB) above the nominal value. This optimal setting improves linearity at mid-range frequencies but reduces dynamic range and causes a drop in high-frequency response, which is offset with pre-emphasis in the recording chain.
Recording very low wavelengths at tape speeds of and presents another challenge. Audible high-frequency components of the recorded signal act as biasing currents, resulting in excessive over-biasing that manifests itself in dynamic range compression and early onset of saturation at high frequencies, especially when recording on low quality tapes with low saturation levels. In the 1970s, music typically published on vinyl records or transmitted on FM radio did not contain much high-frequency energy and usually could not drive the tape into saturation. The digitally mastered, direct-to-disc and disco recordings of the late 1970s and early 1980s, however, often contain enough high-frequency information, or "hot" treble, to trigger tape overload.
In the late 1970s, the recording industry proposed three solutions to the problem. Metal particle tapes had very high maximum output levels and treble saturation levels but were prohibitively expensive for most home users. The early metal tapes had high absolute level of hiss and there were fears metal tape would quickly degrade but this did not happen. The second solution was developed independently by Tandberg and Akai, and relied on limiting recording levels. The patented Tandberg Dyneq and Akai ADRS circuits electronically compressed the signal before it could overload the tape. In 1979, Kenneth James Gundry of Dolby Laboratories proposed the third alternative; adapting the bias current to the treble content of the source signal. The increase in high-frequency energy, which effectively overbiases the tape, would be compensated for with a reciprocal decrease in the output of the bias generator.
The effect of such compensation is evident from the typical magnetization curves. By default, when the source signal's treble energy is low, the recorder operates at a fixed optimal bias current Ib.opt. (blue curve). Initial over-biasing assures good linearity but low sensitivity and low saturation levels. Reduced bias current value of Ib.red. allows operation at higher input and output levels, albeit with a higher sensitivity (red curve). A well-designed adaptively biased circuit must gradually decrease bias current so the increase in sensitivity compensates for the saturation effects. The new, adaptive magnetization curve remains straight (green dotted line) to the maximum recording current Iaf.1. Owing to self-biasing effects, distortion at middle frequencies remains low and intermodulation decreases.
The location of the breakpoint Iaf.o on the control curve and the slope of its high-level segment depend on the frequency of the input signal, and the energy-loss mechanisms in the tape and the recording head. A practical adaptive-biasing system must employ heuristic weighing over the treble frequencies to attain the best performance of a specific recorder. The effect of changes in tape formulations is insignificant in the case of ferric tapes. Different tapes require different optimal bias settings but the bias control curve can be identical for all ferric tapes.
Dolby HX
The original Dolby HX (for 'Headroom eXtension') designed by Gundry for Dolby Laboratories operated as an add-on to the Dolby B noise-reduction encoder. The Dolby B integrated circuit (IC) extracts the envelope of the mid-frequency and treble components of the source signals and uses it to modulate the gain of its side channel. The HX circuit blends together the envelope signals of both stereo channels. The composite envelope modulates the output of a voltage source that powers the common erase/bias generator, thus varying the bias current. Simultaneously, the same envelope modulates the level of high-frequency pre-emphasis of the two recording channels. Controlling both stereo channels with a single bias modulator was deemed acceptable due to the high degree of correlation between the left and right stereo signals, and the poor channel separation of the existing analog sources available to the consumer. Controlling erase and bias currents simultaneously could cause sudden drops in the effectiveness of erasure but this only happened during the loudest passages with much treble content, which was sufficiently higher than any residual unerased signals to make these inaudible.
Independent tests showed Dolby HX could raise the saturation levels at 10–12 kHz by 10 dB. According to Dolby, the improvement was most pronounced with high quality, high coercivity tape formulations. Poor-quality tapes did not significantly respond to adaptive biasing.
Dolby Laboratories launched Dolby HX at the Consumer Electronics Show in June 1979. The system was offered to existing Dolby B licensees at no extra charge. In 19801981, Aiwa, Harman Kardon and TEAC integrated Dolby HX into their cassette decks but no other manufacturers followed suit. Despite favorable reviews, Dolby HX was a marketing and an engineering failure. It was tested and rejected by audio engineers; while most did not disclose their findings, Willi Studer publicly spoke against the adoption of Dolby HX. According to Studer, the shortcomings of Dolby HX greatly outweighed its intended benefits. A 1981 press release by Dolby for the German market indirectly blamed the system's failure on conservatism in the industry. According to Dolby, Dolby HX "intervenes very far into recorder development and cannot simply be added to the existing electronics. It requires a fundamental redevelopment of the recording amplifier." Dolby, however, still hoped Dolby HX would gain acceptance "because it enables high fidelity quality with the future microcassette recorders with a tape speed of 2.4 cm/s". The latter promise did not materialize, either.
The main drawback of Dolby HX was that, being a feedforward control, it monitored the signal at its source but ignored the signal reaching the recording head. Variations in the gain or the frequency response of the recording chain disrupted the bias control curve. The adjustable pre-emphasis sub-circuitry was unnecessarily complex and expensive for the consumer industry. The Dolby B envelope detector, which by design was fairly slow, could not reliably track fast transients. Bundling adaptive biasing with noise reduction at the hardware level was the worst of all shortcomings. The user could not turn off the Dolby B decoder and still use Dolby HX while recording. This discouraged the use of the more effective dbx noise reduction. The 30 dB gain in signal-to-noise ratio provided by dbx made Dolby HX virtually unnecessary.
Dolby HX Pro
In 1980, an alternative implementation of adaptive biasing was patented by Jørgen Selmer Jensen of Bang & Olufsen (B&O). Unlike the feedforward Dolby HX, the B&O circuit was a feedback system. According to the patent, it monitored the high-frequency voltage at the "hot" end of the recording head, extracting the combined envelope of bias and treble audio signals. An error amplifier continuously compared the envelope with the preset reference level and adjusted the bias current being fed to the recording head via a resistive opto-isolator. The monaural circuit was easily scalable for stereophonic and multitrack recording, and enabled easy adjustments of the normal bias level.
According to B&O, its system assured only 3-5 dB gain in treble saturation, far less than Dolby HX. B&O's system did not rely on the Dolby IC and could be used with or without any noise reduction system. Negative feedback compensated for variations in gain and frequency response in the recording chain, eliminating the key shortcoming of Dolby HX. As a side benefit, the B&O system was also effective in reel-to-reel recorders.
Dolby Laboratories acquired the rights to the B&O patent and became its sole worldwide distributor. The new system was named Dolby HX Professional, which was later shortened to Dolby HX Pro. B&O retained the rights to use Dolby HX Pro in its products and, according to sources affiliated with Selmer, received a share of future licensing revenue.
At its launch, Dolby targeted HX Pro at professional markets. In August 1982, industrial tape duplicator manufacturer Electro Sound introduced HX Pro into its cassette-duplicator catalogue. Warner Records became the first major recording label to adopt HX Pro for mass duplication. By February 1983, according to Dolby, the company had two licensees in the home audio industry; Aiwa and Harman Kardon. The early adopters had to build Dolby HX Pro circuitry with general-purpose operational amplifiers and transconductance amplifiers until the 1985 introduction of a dedicated IC, the NEC μPC1297. The new proposal was well received by the industry and by 1986, Dolby HX Pro became a standard feature in the upper segment of consumer cassette decks. In the following years, Dolby HX Pro migrated into the entry-level consumer segment, becoming the de facto standard equipment in consumer hi-fi, and was also integrated into professional reel-to-reel recorders.
Subsequent development
In 1983, adaptive biasing gained popularity in the Soviet Union. The earliest implementation, published by Nikolay Sukhov, was developed after Dolby HX Pro. It blended the elements of HX Pro (feedback control) and Dolby HX, varying the supply voltage to the common erase/bias generator, and added safeguards against transient overload, a common problem when recording from worn LP records. The revised design, which used a new precision rectifier IC, was published in 1987.
In line with the tastes of the home audio community, which still preferred reel-to-reel tapes to cassettes, the 1987 version was targeted at cassette decks and reel-to-reel decks. Adaptive biasing cannot substantially improve the performance of tape running at 19.5 cm/s (7.5 in/s) or higher speeds in standard reel-to-reel recorders; its saturation envelope is suitably high for music signals. Adaptive biasing, however, permits a decrease in treble equalization from the standard 50 μs to 10 μs. A fivefold reduction of the time constant corresponds to a fivefold decrease in apparent noise floor at middle and treble frequencies. According to Sukhov, his system enables a practical signal-to-noise ratio of more than 80 dB, without noise reduction. Sukhov's designs were the subject of five patents issued between 1984 and 1989, all of which referenced the earlier Selmer patent as prior art.
Footnotes
Notes
References
In English
In German
In Russian
Tape recording | Adaptive biasing | [
"Technology"
] | 2,701 | [
"Recording devices",
"Tape recording"
] |
69,867,676 | https://en.wikipedia.org/wiki/Lewandowski-Kurowicka-Joe%20distribution | In probability theory and Bayesian statistics, the Lewandowski-Kurowicka-Joe distribution, often referred to as the LKJ distribution, is a probability distribution over positive definite symmetric matrices with unit diagonals.
Introduction
The LKJ distribution was first introduced in 2009 in a more general context by Daniel Lewandowski, Dorota Kurowicka, and Harry Joe. It is an example of the vine copula, an approach to constrained high-dimensional probability distributions.
The distribution has a single shape parameter and the probability density function for a matrix is
with normalizing constant , a complicated expression including a product over Beta functions. For , the distribution is uniform over the space of all correlation matrices; i.e. the space of positive definite matrices with unit diagonal.
Usage
The LKJ distribution is commonly used as a prior for correlation matrix in Bayesian hierarchical modeling. Bayesian hierarchical modeling often tries to make an inference on the covariance structure of the data, which can be decomposed into a scale vector and correlation matrix. Instead of the prior on the covariance matrix such as the inverse-Wishart distribution, LKJ distribution can serve as a prior on the correlation matrix along with some suitable prior distribution on the scale vector. It has been implemented in several probabilistic programming languages, including Stan and PyMC.
References
External links
Described as part of the Stan manual
distribution-explorer
Random matrices
Bayesian statistics
Continuous distributions
Multivariate continuous distributions | Lewandowski-Kurowicka-Joe distribution | [
"Physics",
"Mathematics"
] | 303 | [
"Random matrices",
"Matrices (mathematics)",
"Statistical mechanics",
"Mathematical objects"
] |
69,867,945 | https://en.wikipedia.org/wiki/Bigoni%E2%80%93Piccolroaz%20yield%20criterion | The Bigoni–Piccolroaz yield criterion is a yielding model, based on a phenomenological approach, capable of describing the mechanical behavior of a broad class of pressure-sensitive granular materials such as soil, concrete, porous metals and ceramics.
General concepts
The idea behind the Bigoni-Piccolroaz criterion is that of deriving a function capable of transitioning between the yield surfaces typical of different classes of materials only by changing the function parameters. The reason for this kind of implementation lies in the fact that the materials towards which the model is targeted undergo consistent changes during manufacturing and working conditions. The typical example is that of the hardening of a power specimen by compaction and sintering during which the material changes from granular to dense.
The Bigoni-Piccolroaz yielding criterion can be represented in the Haigh–Westergaard stress space as a convex smooth surface and in fact the criterion itself is based on the mathematical definition of the surface in the above-mentioned space as a proper interpolation of experimental points.
Mathematical formulation
The Bigoni-Piccolroaz yield surface is thought as a direct interpolation of experimental data. This criterion represents a smooth and convex surface, which is closed both in hydrostatic tension and compression and has a drop-like shape, particularly suited to describe frictional and granular materials. This criterion has also been generalized to the case of surfaces with corners.
Design principles
Since the whole idea of the model is to tailor a function to experimental data, the authors have defined a certain group of features as desirable, even if not essential, among those:
smoothness of the surface;
possibility of changing the shape and thus the interpolation on a broad class of experimental data for different materials;
possibility to represent known criteria with limit set of parameters;
convexity of the surface.
Parametric function
The Bigoni–Piccolroaz yield criterion is a seven-parameter surface defined as:
where p, q and are invariants dependent on the stress tensor, while is the "meridian" function:
describing the pressure-sensitivity and is the "deviatoric" function:
describing the Lode-dependence of yielding.
The mathematical definitions of the parameters and are:
With:
Where is the deviatoric stress, is the identity tensor, is the stress tensor and the dot indicates the scalar product.
A better understanding of those important parameters can be grasped by using their geometrical representation in the Haigh–Westergaard stress space. Considering the tern of principal stresses and the deviatoric plane , orthogonal to the trisector of the first quadrant and passing through the origin of the coordinate system, the tern and unequivocally represents a point in the space acting as a cylindrical coordinate system with the trisector as an axis:
is the distance of the point from the deviatoric plane ;
is the distance from the trisector;
represents the angle between the projections of and the axis on the deviatoric plane .
The usage of p and q instead of the correct cylindrical coordinates and :
is justified by the easier physical interpretation: p is the hydro-static pressure on the material point, q is the Von Mises equivalent stress.
The described yield function corresponds to the yield surface:
which makes explicit the relation between the two functions and and the shape of the meridian and deviatoric sections, respectively.
The seven, non-negative material parameters:
define the shape of the meridian and deviatoric sections. In particular, some of the parameters are easily relatable to mechanical properties: controls the pressure sensitivity, and are the yield strength under isotropic conditions of tension and compression. The other parameters define the shape of the surface when intersected by the meridian and deviatoric planes: and define the meridian section, and define the deviatoric section.
Related yielding criteria
Having been designed to allow consistent changes in the surface shape in the Haigh–Westergaard stress space, the Bigoni-Piccolroaz yield surface can be used as a generalized formulation for several criteria, such as the well known von Mises, Tresca, Mohr–Coulomb.
See also
Yield surface
Yield (engineering)
Plasticity (physics)
Material failure theory
Compaction of ceramic powders
External links
The Bigoni-Piccolroaz yield surface is a powerful instrument for the characterization of granular materials and it arises great interest in the field of the definition of constitutive models for ceramics, rock and soil which is a task of fundamental importance for better design of products using these materials.
https://bigoni.dicam.unitn.it/
https://apiccolroaz.dicam.unitn.it/
https://www.refracture2-h2020.eu/
References
Materials science
Plasticity (physics)
Yield criteria
Structural analysis
Ceramic materials
Ceramic engineering
Powders | Bigoni–Piccolroaz yield criterion | [
"Physics",
"Materials_science",
"Engineering"
] | 995 | [
"Structural engineering",
"Applied and interdisciplinary physics",
"Deformation (mechanics)",
"Structural analysis",
"Materials science",
"Plasticity (physics)",
"Materials",
"Powders",
"Ceramic materials",
"nan",
"Aerospace engineering",
"Mechanical engineering",
"Ceramic engineering",
"M... |
69,875,109 | https://en.wikipedia.org/wiki/CYP154C3 | Cytochrome P450 family 154 subfamily C member 3 (abbreviated CYP154C3) is an actinobacterial Cytochrome P450 enzyme originally from Streptomyces, which catalyzes the 16α-hydroxylation of various steroids.
References
154
Prokaryote genes | CYP154C3 | [
"Biology"
] | 68 | [
"Prokaryotes",
"Prokaryote genes"
] |
69,876,148 | https://en.wikipedia.org/wiki/Weather%20of%202002 | The following is a list of weather events that occurred on Earth in 2002. There were several natural disasters around the world from various types of weather, including blizzards, cold waves, droughts, heat waves, tornadoes, and tropical cyclones. The deadliest disaster was a heat wave in India in May, which killed more than 1,030 people. The costliest event of the year was a flood in Europe in August, which killed 232 people and caused (US$27.115 billion) in damage. In September, Typhoon Rusa struck South Korea, killing at least 213 people and causing at least ₩5.148 trillion (US$4.2 billion) in damage.
Winter storms and cold waves
In October, Cyclone Jeanett killed 33 people when it moved across Europe.
In December, an ice storm affected North Carolina, killing 24 people.
Droughts, heat waves, and wildfires
In May, a heat wave in India killed more than 1,030 people.
A drought affected much of North America.
Floods
In February, flash floods affected the Bolivian capital city La Paz, killing 69 people.
On March 31, flash floods in the Canary Islands killed eight people and left in damage.
In June, floods in northern Chile killed 17 people.
In August, widespread floods occurred throughout Europe, killing 232 people. The floods and (US$27.115 billion) in damage.
Tornadoes
There were 934 tornadoes in the United States alone, collectively resulting in 55 deaths. A tornado outbreak in November killed 36 people.
Tropical cyclones
The year began with Tropical Storm Cyprien developing near Madagascar, Cyclone Bernie developing off Northern Australia, Cyclone Waka moving away from Tonga, and a weak tropical depression near the Solomon Islands. There were a further 15 tropical cyclones in the south-west Indian Ocean in the year, including Cyclone Dina, which caused 15 deaths in the Mascarene Islands, and Cyclone Kesiny, which killed 33 people in Madagascar. The year ended with Tropical Storm Delfina moving ashore Mozambique. In the Australian region, nine tropical cyclones developed in the year after Bernie, including powerful Cyclone Chris which struck Western Australia. In the South Pacific, there were 16 tropical cyclones that developed after Waka. The year ended with Cyclone Zoe moving away from Fiji, three days after it became the second-most intense tropical cyclone on record within the Southern Hemisphere.
The first storm to develop in the northern hemisphere was Tropical Storm Tapah on January 9 east of the Philippines. There were a total of 36 tropical cyclones that year. Among the storms were Typhoon Rusa, which was the most powerful typhoon to strike South Korea in 43 years, and which caused at least 213 fatailties and ₩5.148 trillion (US$4.2 billion). Tropical Storm Kammuri killed 153 people in China. Mudslides caused by Typhoon Chataan killed 47 people in the Federated States of Micronesia, becoming the deadliest natural disaster in the history of Chuuk State. In the North Indian Ocean, there were seven tropical cyclones, beginning with a cyclonic storm that struck Oman in May. In November, a cyclonic storm struck West Bengal, killing 173 people. There were 19 tropical cyclones in the eastern Pacific, including three Category 5 hurricanes – Elida, Hernan, and Kenna. The last of the three, Kenna, also struck southwestern Mexico. In the Atlantic Ocean, there were 14 tropical cyclones, nine of which formed in September, including hurricanes Isidore and Lili which moved through the Caribbean and into the southern United States.
References
Weather by year
Weather-related lists
2002-related lists | Weather of 2002 | [
"Physics"
] | 733 | [
"Weather",
"Physical phenomena",
"Weather by year",
"Weather-related lists"
] |
69,876,236 | https://en.wikipedia.org/wiki/Helen%20Marshall%20%28vaccinologist%29 | Helen Siobhan Marshall (born 1962) is an Australian medical researcher who is Professor of Vaccinology at the University of Adelaide. She was named the South Australian of the Year for 2022.
Early life and education
Marshall's mother was a nurse and her father a general practitioner. She completed her schooling at Pembroke School, Adelaide in 1979.
Marshall graduated from the University of Adelaide with an MBBS in 1988. She returned to the university for postgraduate studies, receiving a Masters in Public Health in 2004 and a Doctorate of Medicine in 2011. She has also completed an international Advanced Vaccinology Course at the Pasteur Institute in France.
Career
As a medical student, Marshall worked for a time in Western Samoa, which she has said has "guided her interest" in vaccinology. She then undertook paediatric training at the Women's and Children's Hospital in Adelaide, where she saw the impact of serious infections from diseases without vaccines available.
Marshall focused on research in vaccinology, public health and infectious diseases. She is Professor of Vaccinology in the Adelaide Medical School and Deputy Director, Clinical and Translational Research for the Robinson Research Institute at the University of Adelaide. She is also a Senior Medical Practitioner and Medial Director for Vaccinology and Immunology Research Trials Unit at the Women's and Children's Hospital.
Marshall was awarded NHMRC Career Development Fellowships in 2011 and 2015, and a Practitioner Fellowship in 2019. She has published over 211 peer-reviewed papers and been awarded 17 research grants totalling more than $33 million. She has been a member of Australian Technical Advisory Group on Immunisation and continues to provide vaccination evaluations for the group, and she is an advisor to the World Health Organization.
Marshall's research focus throughout her career has been on development of vaccines for meningococcal disease. She conducted a three-year large scale study of over 42,000 people across South Australia, the largest study of its kind and one that has been called a "game-changer", which will inform global research and understanding about the disease.
During the COVID-19 pandemic, Marshall provided advice to the state's Health Minister Stephen Wade and Chief Public Health Officer Nicola Spurrier and was cited as one of Australia's leading vaccination experts. Commencing in September 2020, Marshall was co-investigator at the University of Sydney in a Phase I Human Trial of a novel DNA-based COVID-19 vaccine developed by BioNet and Technovalia that could be administered without using a needle. She is also part of a University of Queensland research team seeking to improve primary health care services for Aboriginal and Torres Strait Islander peoples and is leading a study to provide free meningococcal B vaccinations to Northern Territory residents as she studies whether the vaccine can also provide protection against gonorrhoea.
In October 2021, Marshall was named South Australian of the Year for her work in public health and infectious diseases, making her the state's nominee for Australian of the Year. She was made a Member of the Order of Australia in the 2022 Australia Day Honours.
Awards and honours
2010 South Australia Science Award, Excellence in Research for the Public Good
2019 SA Science Awards Excellence in Research Collaboration
2020 Australia Day Council South Australian Inspiring Women award
2021 Fellow of the Australian Academy of Health and Medical Sciences
2022 South Australian of the Year
2022 Member of the Order of Australia
Personal life
During her paediatric training, Marshall married fellow doctor David Misan. They have three children.
Selected publications
References
Living people
1962 births
Members of the Order of Australia
Fellows of the Australian Academy of Health and Medical Sciences
Scientists from Adelaide
University of Adelaide Medical School alumni
Academic staff of the University of Adelaide
Vaccinologists
Australian women medical researchers
Australian medical researchers
People educated at Pembroke School, Adelaide | Helen Marshall (vaccinologist) | [
"Biology"
] | 778 | [
"Vaccination",
"Vaccinologists"
] |
69,876,714 | https://en.wikipedia.org/wiki/Raman%20Engine | Raman Engine is a bipropellant rocket engine manufactured by Skyroot Aerospace that will be used in its Vikram family of rockets. It is named after Indian Nobel laureate Sir C.V. Raman.
Description
It uses UDMH and NTO hypergolic propellants. Its injector plate is completely 3D printed. This engine will be used in a cluster of 4 in the fourth stage of the Vikram 1 rocket, which can produce a thrust of 3.4 kN each producing 850 N of thrust, which is lower than many other rocket engines, but is required for precise orbit adjustments.
Development and Testing
On 12 August 2020, Skyroot Aerospace successfully tested the engine for the first time.
References
Rocket engines of India
Rocket engines using hypergolic propellant | Raman Engine | [
"Astronomy"
] | 160 | [
"Rocketry stubs",
"Astronomy stubs"
] |
69,879,102 | https://en.wikipedia.org/wiki/Martin%20Williams%20%28environmental%20scientist%29 | Martin Lloyd Williams (22 November 1947–21 September 2020) was a Welsh chemist and environmental scientist who made important contributions to the science of air pollution and its incorporation into public policy in the United Kingdom. Williams was one of the first scientists to recognize the harmful health effects of ground-level ozone, in papers published in Nature in the mid-1970s, and one of the first to study vehicle emissions in the real world (rather than under artificial laboratory conditions). He also established the first systematic programme to produce inventories of UK national air pollution emissions.
Early life
Born in Mountain Ash, Williams studied chemistry at University College, Cardiff, took a Ph.D. at Bristol University, and held research fellowships at the University of British Columbia and the University of Bradford.
Government career
In 1975, he became a government scientist at the Department of Industry's environmental research centre, Warren Spring Laboratory in Stevenage, and served as Head of the Air Pollution Division there, leading a team of 50 scientists, from 1982 to 1993. He moved to the UK government's Department of Environment in 1993. In 2005, he became head of the air quality and science programme at the Department for Environment, Food and Rural Affairs, where he focused on translating air pollution science into effective government policy, and developed three national air quality strategies for the UK.
Academic career
In 2010, Williams returned to academia as a professor and Head of Science Policy and Epidemiology in the Environmental Research Group at King's College London, where his research interests included the air quality in London, the measureable health benefits of improved air quality, and the connections between climate change and air pollution. He was also a visiting professor at the University of Urbino, Italy.
Other activities
Apart from his government and academic appointments, he was chair of the scientific arm of the UN Convention on Long-Range Transboundary Air Pollution (CLRTAP), co-chair of the World Health Organization (WHO) working group on air quality guidelines, an air quality adviser to the US Environmental Protection Agency, and a member of the UK government's two scientific, air pollution advisory committees (AQEG and COMEAP). In 2019, he became one of three Clean Air Champions (alongside Sir Stephen Holgate and Jenny Baverstock) appointed by the UK government's Clean Air programme, tasked with using scientific research to inform practical solutions to the problem of air pollution. Shortly before his death, the Institute of Air Quality Management invited him to be its inaugural Honorary Fellow.
Williams died in 2020 of the heart condition hemopericardium.
Selected publications
References
External links
Professor Martin Williams: Interview on Air Pollution, UN Economic Commission for Europe (UNECE), 11 November 2013.
1947 births
2020 deaths
Welsh chemists
Academics of Imperial College London
Academics of King's College London
People from Rhondda Cynon Taf
Environmental scientists
Air pollution in the United Kingdom | Martin Williams (environmental scientist) | [
"Environmental_science"
] | 586 | [
"Environmental scientists",
"British environmental scientists"
] |
69,880,929 | https://en.wikipedia.org/wiki/The%20Simple%20Function%20Point%20method | The Simple Function Point (SFP) method is a lightweight Functional Measurement Method.
The Simple Function Point method was designed by Roberto Meli in 2010 to be compliant with the ISO14143-1 standard and compatible with the International Function Points User Group (IFPUG) Function Point Analysis (FPA) method. The original method (SiFP) was presented for the first time in a public conference in Rome (SMEF2011)
The method was subsequently described in a manual produced by the Simple Function Point Association: the Simple Function Point Functional Size Measurement Method Reference Manual, available under the Creatives Commons Attribution-NoDerivatives 4.0 International Public License.
Adoption by IFPUG
In 2019, the Simple Function Points Method was acquired by the IFPUG, to provide its user community with a simplified Function Point counting method, to make functional size measurement easier yet reliable in the early stages of software projects. The short name became SFP. The SPM (Simple Function Point Practices Manual) was published by IFPUG in late 2021.
Basic concept
When the SFP method was proposed, the most widely used software functional size measurement method was IFPUG FPA. However, IFPUG FPA had (and still has) a few shortcomings:
It is not easy to apply. It requires certified personnel, and the productivity of measurement is relatively low (between 400 and 600 Function Points per day, according to Capers Jones, between 200 and 300 Function Points per day according to experts from Total Metrics ).
The measurement is partly subjective, since some of its measurement rules have to be suitably interpreted by the person who performs the measurement.
The diffusion of the method in the software development community is quite limited.
To overcome at least some of these problems, the SFP method was defined to provide the following characteristics:
Easy to apply;
Less subject to interpretation, being based on quite straightforward definitions;
Easy to learn: specifically, people familiar with IFPUG FPA could learn SFP very quickly with very little effort;
Compatible with the IFPUG FPA; specifically , that is, a measure of size expressed in UFP should be equal to the measure expressed in SiFP (In this article we use “UFP” for unadjusted Function Point to designate the unit of measure defined by IFPUG FPA and SiFP the unit of measure defined by SFP).
The sought characteristics were achieved as follows:
IFPUG FPA requires that
logical data files and transactions are identified,
logical data files are classified into Internal Logical Files (ILF) and External Interface Files (EIF),
every transaction is classified as External Input (EI), External Output (EO), External Query (EQ),
every ILF and EIF is weighted, based on its Record Element Types (RET) and Data Element Types (DET),
every EI, EO and EQ is weighted, based on its File Types Referenced (FTR) and DET exchanged through the borders of the application being measured.
Of these activities, SFP requires only the first two, i.e., the identification of logical data files and transactions. Activities 4) and 5) are the most time consuming, since they require that every data file and transaction is examined in detail: skipping these phases makes the SFP method both quicker and easier to apply than IFPUG FPA. In addition, most of the subjective interpretation is due to activities 4) and 5), and partly also to activity 3): skipping these activities makes the SFP method also less prone to subjective interpretation.
The concepts used in the definition of SFP are a small subset of those used in the definition of IFPUG FPA, therefore learning SFP is easier than learning IFPUG FPA, and it is immediate for those who already know IFPUG FPA. In practice, only the concepts of logical data file and transaction have to be known.
Finally, the weights assigned to data files and transactions make the size in SFP very close to the size expressed in Function Points, on average.
Definition
The logical data files are named Logical Files (LF) in the SFP method. Similarly, transactions are named Elementary Process (EP). Unlike in IFPUG FPA, there is no classification or weighting of the Base Functional Components (BFC as defined in ISO14143-1 standard).
The size of an EP is 4.6 SFP, while the size of a LF is 7.0 SFP. Therefore the size expressed in SFP is based on the number of data files (#LF) and the number of transactions (#EP). Belonging to the software application being measured:
Empirical evaluation of the SFP method
Empirical studies have been carried out, aiming at
evaluating the convertibility of SFP and UFP measures
comparing the SFP and UFP measures in supporting the estimation of software development effort
Convertibility between SFP and FPA measures
In the original proposal of the SiFP method, a dataset from the ISBSG, including data from 768 projects, was used to evaluate the convertibility among UFP and SiFP measures. This study showed that on average .
Another study also used an ISBSG dataset to evaluate the convertibility among UFP and SiFP measures. The dataset included data from 766 software applications. Via ordinary least square regression, it was found that .
Based on these empirical studies, it seems that (note that this approximate equivalence holds on average: in both studies an average relative error around 12% was observed).
However, a third study found . This study used data from only 25 Web applications, so it is possible that the conversion rate is affected by the specific application type or by the relatively small size of the dataset.
In 2017, a study evaluated the convertibility between UFP and SiFP measures using seven different datasets. Every dataset was characterized by a specific conversion rate. Specifically, it was found that , with . Noticeably, for a dataset, no linear model could be found; instead the statistically significant model was found.
In conclusion, available evidence shows that one SiFP is approximately equivalent to one UFP, but this equivalence depends on the data being considered, besides being true only on average.
Considering that the IFPUG SFP basic elements (EP, LF) are totally equivalent to the original SiFP elements (UGEP, UGDG), the previous results hold for the IFPUG SFP method as well.
Using SFP for software development effort estimation
IFPUG FPA is mainly used for estimating software development effort. Therefore, any alternative method that aims at measuring the functional size of software should support effort estimation with the same level of accuracy as IFPUG FPA. In other words, it is necessary to verify that effort estimates based on SFP are at least as good as the estimates based on UFP.
To perform this verification, an ISBSG dataset was analyzed, and models of effort vs. size were derived, using ordinary least squares regression, after log-log transformations. The effort estimation errors were then compared. It turned out that the two models yielded extremely similar estimation accuracy.
A following study analyzed a dataset containing data from 25 Web applications. Ordinary least squares regression was used to derive UFP-based and SiFP-based effort models. Also in this case, no statistically significant estimation differences could be observed.
References
External links
The introduction to Simple Function Points (SFP) from IFPUG.
Software metrics
Software engineering costs | The Simple Function Point method | [
"Mathematics",
"Engineering"
] | 1,553 | [
"Software engineering",
"Quantity",
"Metrics",
"Software metrics"
] |
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