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62,798,842 | https://en.wikipedia.org/wiki/Eloisa%20Biasotto%20Mano | Eloisa Biasotto Mano (October 24, 1924 – June 8, 2019) was a Brazilian chemist and full university professor. She was a specialist in polymers, and enjoyed worldwide recognition for her work. She was a recipient of the National Order of Scientific Merit.
Early life and education
Eloisa Biasotto Mano was born in Rio de Janeiro, October 24, 1924. She received degrees in industrial chemistry (1947), chemical engineering (1955), and a doctorate in organic chemistry (1960). She studied polymer science at the University of Illinois and at the University of Birmingham.
Career
In Brazil, she formed the first group of researchers in the area of polymers, which gave rise to the Institute of Macromolecules of Federal University of Rio de Janeiro (UFRJ), later renamed in her honor. Mano taught organic chemistry at the Institute of Chemistry, UFRJ, where she was a full professor. She supervised many master's and doctoral theses. In her classes, Mano was always keen to demonstrate practically the properties of different materials and their characterizations. She received the National Order of Scientific Merit for her contribution to science. She was a full member of the Brazilian Academy of Sciences since 1978. In 1994, she became Professor Emeritus.
Mano died in Rio de Janeiro, June 8, 2019.
Awards and honors
2000, Grand Cross, National Order of Scientific Merit
2000, City of Rio de Janeiro Award for Science and Technology
2001, Simão Medal, Matias, Brazilian Chemical Society (SBQ)
2003, creation of the Profa Prize. Eloisa Bro, Brazilian Polymer Association
Selected works
Praticas de quimica organica, 1969
Modified Lignan Polymers from the Resin of Paraná Pine Tree Knots
Introducao a polimeros, 1999
Identificação de plásticos, borrachas e fibras, 2000
Tensile behavior of irradiated recycled polyolefin plastics, 2000
Química experimental de polímeros, 2004
Meio ambiente, poluição e reciclagem, 2005
O impacto do acordo NAS/CNPq na evolução da Química no Brasil: o setor de polímeros, 2007
Natural Polymer Characterization, 2007
Polímeros como materiais de engenharia, 2019
References
1924 births
2019 deaths
Scientists from Rio de Janeiro (city)
Brazilian chemists
20th-century British educators
20th-century British women educators
Polymers
University of Illinois Urbana-Champaign alumni
Alumni of the University of Birmingham
Academic staff of the Federal University of Rio de Janeiro
Recipients of the National Order of Scientific Merit (Brazil)
Brazilian science writers
20th-century Brazilian women writers
21st-century Brazilian women writers
21st-century Brazilian writers
Brazilian expatriates in the United Kingdom
Brazilian expatriates in the United States | Eloisa Biasotto Mano | [
"Chemistry",
"Materials_science"
] | 575 | [
"Polymers",
"Polymer chemistry"
] |
62,799,717 | https://en.wikipedia.org/wiki/Molybdenum%28IV%29%20bromide | Molybdenum(IV) bromide, also known as molybdenum tetrabromide, is the inorganic compound with the formula MoBr4. It is a black solid. MoBr4 has been prepared by treatment of molybdenum(V) chloride with hydrogen bromide:
2 MoCl5 + 10 HBr → 2 MoBr4 + 10 HCl + Br2
The reaction proceeds via the unstable molybdenum(V) bromide, which releases bromine at room temperature.
Molybdenum(IV) bromide can also be prepared by oxidation of molybdenum(III) bromide with bromine.
References
Bromides
Molybdenum halides
Molybdenum(IV) compounds | Molybdenum(IV) bromide | [
"Chemistry"
] | 162 | [
"Bromides",
"Salts"
] |
62,800,705 | https://en.wikipedia.org/wiki/Konagas%C5%8D%20Pottery%20Kiln%20ruins | The is an archaeological site containing a Muromachi period kiln located in the Higashishirasaka neighborhood of the city of Seto, Aichi in the Tōkai region of Japan. The site was designated a National Historic Site of Japan in 1971. with the area under protection expanded in 2002.
Overview
Located in the hills of eastern Seto, this kiln was built in the Muromachi period and is recorded as having been in use until the early modern era. Some 800 kiln ruins have been discovered around the city of Seto, which for centuries has been one of the major pottery production sites in Japan, and of these 800 kilns, some 100 date from the "old Seto" period. The Konagasō kiln is one of the best-preserved of these kiln ruins, as most have been destroyed or vandalized over the years. The ruins were known since the Edo period and in 1946 this was the first kiln site to be excavated by the Japan Ceramic Association.
Excavations have found that the kiln is an anagama-style kiln with semi-underground structure utilizing the natural slope of the hill. It has a total length of 6.7 meters and maximum width of three meters, and is divided into three parts. The firing chamber and combustion chamber are connected by a barrier with six holes located along its bottom. The use of such through-holes is very rare for old Seto kilns. This kiln is considered a predecessor for the later noborigama-style design.
A large number of shards of Seto ware were discovered in the ash and debris in front of the kiln and were found to be from a wide variety of jars, vases and other objects. The pottery shards were found to be mostly without pattern. Subsequent archaeological excavations have confirmed the remains of a workshop and a large ash field that spreads around the kiln, creating a slope. The site is thus of great significance in understanding the production technology, equipment, and worker organization for early Seto pottery. A structure with a barrier and five stanchions in the center of the kiln is unique. Tea utensils such as tea bowls from the Edo period and kiln tools for producing them have been excavated from a narrow area in front of the kiln's opening and have been dated to the end of the 17th century and 18th century . This shows that the medieval kiln was modified and reused during the Edo Period.
The kiln ruins are located about 30 minutes on foot from the "Unkouji" bus stop on the Meitetsu Bus from Owari Seto Station on the Meitetsu Seto Line.
See also
List of Historic Sites of Japan (Aichi)
References
External links
Seto city official site
Muromachi period
History of Aichi Prefecture
Seto, Aichi
Historic Sites of Japan
Japanese pottery kiln sites | Konagasō Pottery Kiln ruins | [
"Chemistry",
"Engineering"
] | 588 | [
"Kilns",
"Japanese pottery kiln sites"
] |
65,645,973 | https://en.wikipedia.org/wiki/Margaret%20A.%20Davidson | Margaret A. Davidson (March 2, 1950 - May 23, 2017) was a coastal management pioneer. She spent most of her career working within the National Oceanic and Atmospheric Administration (NOAA), taking leadership roles that drew from her expertise in climate adaptation, sustainable coastal development, and mitigating risk associated with extreme weather events. Among these roles, Davidson served as senior leader on coastal inundation and resilience for NOAA. She is remembered as a "visionary" in coastal science and management, especially for her capacity to engage communities and consider local social and economic issues while making coastal management decisions.
Career
She started her career in coastal science and management in 1978 with a Juris Doctor from Louisiana State University. Davidson briefly served as special counsel and assistant attorney for the Louisiana Department of Justice. She later earned her master's degree from the University of Rhode Island in marine policy and resource economics. Following this, she joined the South Carolina Sea Grant Consortium where she worked for 16 years, eventually becoming executive director for 13 of those years. In 1995, she joined NOAA as the founding director of the Coastal Services Center. She served as the acting assistant administrator for the NOAA National Ocean Service 2000–2002. From April 2012 to May 2014, she was acting director of the Office of Ocean and Coastal Resource Management, and then oversaw the merging with the Coastal Services Center in 2013 to become what is now the NOAA Office for Coastal Management. In 2014, she became NOAA's Senior Scientific Advisor on Coastal Inundation and Resilience where she evaluated all NOAA coastal inundation efforts.
Advocacy for climate adaptation
Davidson recognized that there was a missing link between science and local decision-making that created an obstacle in climate adaptation. She understood that local political offices were often more concerned with and more capable of preparing for the short-term risk of the next storm, than they were with preparing for the seemingly long-term threat of sea level rise. She invested in efforts to restore local wetlands that provided sea-level rise mitigation and in creating coastal zone risk maps that would effectively communicate the science behind sea-level rise.
Margaret was a stark proponent that good science is a necessary foundation to any management decision or program. She maintained that studies needed to understand coastal inundation risk from the environmental, community, and governance characteristics of the region in order to be successful. This information in tandem with publicized discussions could lead to decisions that reduce future losses to homes, private development, public infrastructure and repetitive losses of government funds.
She spoke to the urgent need to establish policies and initiatives for climate and sea-level rise adaptation, and was not afraid to be critical of the roles federal and state agencies played in this.
Recognition and awards
Fulbright Scholar at Prince of Songkhla University, Thailand for coastal resource management in 1992
Nobel Prize for the Intergovernmental Panel on Climate Change and Albert (Al) Gore Jr. in 2007
Presidential Merit Award in 2002 and 2010
American Meteorological Society Fellow since 2009
Gilbert White Fellow
Zurich Fellow for Climate Adaptation
NOAA's Administrator Award in 2014
Coastal and Estuarine Research Foundation's Margaret A. Davidson Stewardship Award - Awarded to individuals that have shown leadership and commitment to the management of estuarine and coastal systems.
NOAA Margaret A. Davidson Fellowship- Two-year professional development fellowship for graduate students to conduct research and educational outreach at one of the National Estuarine Research Reserves.
Margaret A. Davidson Coastal Career Development Program - Hosted by The Coastal Society this program is a series of career development workshops for early- and mid-career coastal scientists and managers.
Personal life
Davidson was raised in Fort Worth, Texas. She married her partner of more than 30 years Karen Stevens in the summer of 2013 in Washington D.C.
References
Women Nobel laureates
American women scientists
University of Rhode Island alumni
Louisiana State University alumni
1950 births
2017 deaths | Margaret A. Davidson | [
"Technology"
] | 780 | [
"Women Nobel laureates",
"Women in science and technology"
] |
65,646,215 | https://en.wikipedia.org/wiki/Hexaaza-18-crown-6 | Hexaaza-18-crown-6 is the macrocyclic ligand with the formula (CH2CH2NH)6. A white solid, this compound has attracted attention as the N6-analogue of 18-crown-6. It functions as a hexadentate ligand in coordination chemistry. It is the parent hexaaza-crown ether.
Its protonated derivatives bind anions via multiple hydrogen bonds.
References
Polyamines
Ethyleneamines
Chelating agents
Macrocycles
Hexadentate ligands | Hexaaza-18-crown-6 | [
"Chemistry"
] | 111 | [
"Organic compounds",
"Chelating agents",
"Macrocycles",
"Process chemicals"
] |
65,646,717 | https://en.wikipedia.org/wiki/Christiaan%20Huygens%20Medal | The Christiaan Huygens Medal, named after the mathematician and natural philosopher Christiaan Huygens, is a prize awarded by the European Geosciences Union to promote excellence in geosciences and space science.
List of prizewinners
2021 R. Giles Harrison
2020 Raffaele Persico
2019 Lev V. Eppelbaum
2018 Jothiram Vivekanandan
2017 Riccardo Lanari
2016 Karl U. Schreiber
2015 Kristine M. Larson
2011 Martin Hürlimann
2010
2009 Valery Korepanov
2008
References
External links
Christiaan Huygens Medal on the European Geosciences Union website
Astronomy prizes
Awards of the European Geosciences Union
Awards established in 2008 | Christiaan Huygens Medal | [
"Astronomy",
"Technology"
] | 148 | [
"Science and technology awards",
"Astronomy prizes"
] |
65,647,112 | https://en.wikipedia.org/wiki/Portogloboviridae | Portogloboviridae is a family of dsDNA viruses that infect archaea. It is a proposed family of the realm Varidnaviria, but ICTV officially puts it as incertae sedis virus. Viruses in the family are related to Helvetiavirae. The capsid proteins of these viruses and their characteristics are of evolutionary importance for the origin of the other Varidnaviria viruses since they seem to retain primordial characters.
Description
The virions in this family have a capsid with icosahedral geometry and a viral envelope that protects the genetic material. The diameter is 83 to 87 nanometers. The genome is circular dsDNA with a length of 20,222 base pairs. The genome contains 45 open reading frames (ORFs), which are closely arranged and occupy 89.1% of the genome. ORFs are generally short, with an average length of 103 codons. Virions have 10 proteins ranging from 20 to 32 kDa. Of these proteins, 8 code for the capsid and two for the viral envelope, including one that is a vertical single jelly roll (SJR) capsid protein. Entry into the host cell is by penetration. Viral replication occurs by chronic infection without a lytic cycle.
The Portogloboviridae viruses together with Halopanivirales have evolutionary importance in the evolution of the other Varidnaviria viruses since they appear to be relics of how the first viruses of this realm were. Portogloboviridae together with Halopanivirales may have infected the last universal common ancestor (LUCA) and originated before that organism.
It has been proposed that it may be related to the origin of Varidnaviria in the following way.
Taxonomy
The family has one genus which has two species:
Alphaportoglobovirus
Alphaportoglobovirus SPV2
Sulfolobus alphaportoglobovirus 1
References
DNA viruses | Portogloboviridae | [
"Biology"
] | 400 | [
"Viruses",
"DNA viruses"
] |
65,647,556 | https://en.wikipedia.org/wiki/Nomurabacteria | Nomurabacteria is a candidate phylum of bacteria belonging to the CPR group. They are ultra-small bacteria that have been found in a wide variety of environments, mainly in sediments under anaerobic conditions.
Bacteria of this phylum share several of their characteristics with other ultra-small bacteria, nanometric size, small genomes, reduced metabolism, and low capacity to synthesize nucleotides and aminoacids. They also lack respiratory chains and the Krebs cycle. In addition, many can be endosymbionts of larger bacteria.
Phylogenetic analyzes have suggested that Nomurabacteria and the other ultra-small bacteria make up the most basal clade of all bacteria. The archaea of the DPANN group are ultra-small archaea that share the same characteristics with these bacteria and are the most basal group of the archaeo-eukaryotic clade, although it can also be paraphyletic of eukaryotes and the other archaea as will be seen below.
In some phylogenetic analyzes of the proteome, ultra-small bacteria emerge outside the traditional bacterial domain and instead emerge as a paraphyletic group of traditional Bacteria and the clade composed of archaea and eukaryotes. In these analyzes Nomurabacteria turns out to be the most basal clade of all cellular organisms.
Phylogeny
Proteome analyzes have shown that Nomurabacteria can be the most basal clade of cellular organisms and that the other CPR bacteria are a paraphyletic group as can be seen in the cladogram that shows the phylogenetic relationships between multiple bacterial, archaean and eukaryotes.
References
Bacteria
Candidatus taxa | Nomurabacteria | [
"Biology"
] | 356 | [
"Prokaryotes",
"Microorganisms",
"Bacteria"
] |
65,648,046 | https://en.wikipedia.org/wiki/List%20of%20social%20platforms%20with%20at%20least%20100%20million%20active%20users | This is a list of social platforms with at least 100 million monthly active users. The list includes social networks, as well as online forums, photo and video sharing platforms, messaging and VoIP apps.
Integrated services
See also
List of virtual communities with more than 1 million users
List of social networking services
Notes
References
Internet-related lists | List of social platforms with at least 100 million active users | [
"Technology"
] | 67 | [
"Computing-related lists",
"Computing and society",
"Internet-related lists",
"Social media"
] |
65,648,689 | https://en.wikipedia.org/wiki/OdK2 | OdK2 is a toxin found in the venom of the Iranian scorpion Odonthobuthus doriae. It belongs to the α-KTx family, and selectively blocks the voltage-gated potassium channel Kv1.3 (KCNA3).
Etymology
Odonthobuthus doriae is a scorpion species that belongs to the Buthidae family, mainly found in central and southern Iran. OdK2 is an acronym indicating the toxins originating species, the type of ion channel it targets and the chronological order of its discovery. OdK1 was the first toxin isolated from the same species’ venom, targeting the Kv1.2 channel (KCNA2).
Chemistry
OdK2 is a relatively small peptide with 38 amino acids and a monoisotopic mass of 4079.869 Da (C167H278N54O49S8).
According to the unified nomenclature for short-chain peptides isolated from scorpion venoms, Odk2 can be classified in the second α-KTx family, selectively blocking voltage-gated potassium channels.
OdK2 is further classified as α-KTx 3.11 as it presents significant sequence homology with toxins from the α-KTx 3.x sub-family, especially Bs6, Agitoxin and Kaliotoxin. This fact suggests that frequently observed structural motifs present on other toxins of the same subfamily, such as the α/β scaffold and the typical disulfide pairing, can be assumed for OdK2 as well.
The presence of Lys27 and Phe25 residues, crucial for the α-KTx3-Kv1.3 interaction, is another highly conserved feature among α-KTx toxins.
Mode of action
OdK2 is one of the many Kv1.3 channel blockers found in the scorpion’s venom. There is evidence suggesting that their binding mechanism to Kv1.3 is governed by electrostatic forces, exerted between specific amino acid residues in the toxins and in the pore regions of the channel’s subunits. However, the precise OdK2 blocking mechanism remains unknown.
Two prominent features of OdK2 are its blocking potency (IC50 value of 7.27 ± 2.7 nM) and its high selectivity for Kv1.3 channels, illustrated by 95% inhibition at a concentration of 35 nM, but no observed effect in other voltage-gated potassium channels. Amino acid residues only found in Kv1.3 pore regions and not in other Kv1.x channel family members, could potentially explain the high selectivity of OdK2.
Kv1.3 channels are delayed rectifier channels. Their main function is to repolarize the membrane, counterbalancing the depolarizing effect of calcium influx. As the precise modulation of intracellular calcium concentration is critical for the cell's activation and proliferation, occlusion of the potassium channels has a strong effect on the cell’s calcium signaling pathway, indirectly disrupting its normal function.
Toxicity
Observed effects of OdK2 infection include local pain, muscle paralysis and may lead to inflammation and necrosis.
References
Scorpion toxins
Ion channel toxins
Neurotoxins | OdK2 | [
"Chemistry"
] | 684 | [
"Neurochemistry",
"Neurotoxins"
] |
65,650,431 | https://en.wikipedia.org/wiki/Ministry%20of%20Energy%2C%20Mines%20and%20Environment%20%28Morocco%29 | Ministry of Energy Transition and Sustainable Development is a Moroccan Ministry charged with implementing national strategies in the fields of geology, minerals, hydrocarbons and energies, and building the necessary human competencies in these fields. The current minister is Leila Benali.
Institutions affiliated with the Ministry
The Ministry of Energy, Mines and Environment supervises many institutions related to the Ministry's responsibilities:
National Office of Electricity and Drinking Water
OCP Group
Energy Investment Company (SIE)
Moroccan Agency for Sustainable Energy (MASEN)
National Office of Hydrocarbons and Minerals
Institute for Research in Solar Energy and New Energies (IRESEN)
Moroccan Agency for Energy Efficiency (AMEE)
Moroccan Agency for Security and Safety in the Nuclear and Radiation Fields (AMSENOR)
National Center for Energy, Science and nuclear Techniques
Minerals Institute Marrakech
Higher National School for Minerals in Rabat
See also
Government of Morocco
References
External links
Website
Government ministries of Morocco
Morocco
Morocco
Morocco | Ministry of Energy, Mines and Environment (Morocco) | [
"Engineering"
] | 189 | [
"Energy organizations",
"Energy ministries"
] |
65,653,642 | https://en.wikipedia.org/wiki/HD%2099706 | HD 99706 is an orange-hued star in the northern circumpolar constellation of Ursa Major. With an apparent visual magnitude of 7.65, it is too dim to be visible to the naked eye but can be viewed with a pair of binoculars. Parallax measurements provide a distance estimate of approximately 480 light years from the Sun, and the Doppler shift shows it is drifting closer with a radial velocity of −30 km/s. It has an absolute magnitude of 2.12, indicating it would be visible to the naked eye as a 2nd magnitude star if it were located 10 parsecs away.
This is an aging subgiant star belonging to spectral class K0, having exhausted the supply of hydrogen at its core and begun to evolve into a giant. Its age is younger than the Sun's at billion years and it is spinning slowly with a projected rotational velocity of 2 km/s. The star has 1.5 times the mass of the Sun and has expanded to 5.5 times the Sun's radius. It is slightly enriched in heavy elements, having 110% of solar abundance. HD 99706 is radiating 13 times the luminosity of the Sun from its photosphere at an effective temperature of 4,862 K.
An imaging survey at Calar Alto Observatory in 2016 failed to detect any stellar companions to HD 99706.
Planetary system
In 2011 one superjovian exoplanet, HD 99706 b, on a mildly eccentric orbit around star HD 99706 was discovered utilizing the radial velocity method. Another superjovian exoplanet on an outer orbit was detected in 2016.
References
K-type subgiants
Planetary systems with two confirmed planets
Ursa Major
J11283020+4357597
Durchmusterung objects
99706
055994 | HD 99706 | [
"Astronomy"
] | 378 | [
"Ursa Major",
"Constellations"
] |
65,653,885 | https://en.wikipedia.org/wiki/Curtailment%20%28electricity%29 | In electric grid power generators, curtailment is the deliberate reduction in output below what could have been produced in order to balance energy supply and demand or due to transmission constraints. The definition is not strict, and several types of curtailment exist. "Economic dispatch" (low market price) is the most common.
Curtailment is a loss of potentially useful energy, and may impact power purchase agreements. However, utilizing all available energy may require costly methods such as building new power lines or storage, becoming more expensive than letting surplus power go unused.
Examples
After ERCOT built a new transmission line from the Competitive Renewable Energy Zone in West Texas to the central cities in the Texas Interconnection in 2013, curtailment was reduced from 8-16% to near zero.
Curtailment of wind power in western China was around 20% in 2018.
In 2018, curtailment in the California grid was 460 GWh, or 0.2% of generation. Curtailment has since increased to 150-300 GWh/month in spring of 2020 and 2021, mainly solar power at noon as part of the duck curve.
In Hawaii, curtailment reached 20% on the island of Maui in Hawaii in the second and third quarters of 2020.
Mitigation options
Transmission upgrade
Demand response
Battery storage power station
Energy forecasting, including forecasting for price, wind and solar
References
External links
Increase in curtailment in California, 2014—2022
Curtailment curves in South Australia, peaking at 69% (Christmas 2021)
Electrical engineering | Curtailment (electricity) | [
"Engineering"
] | 316 | [
"Electrical engineering"
] |
65,656,179 | https://en.wikipedia.org/wiki/The%20Institute%20of%20Chemists%20PNG | The Institute of Chemistry PNG is the professional organisation supporting chemical sciences in Papua New Guinea and a learned society promoting the science and practice of chemistry.
Affiliations
The Institute of Chemistry PNG is a member of the Federation of Asian Chemical Societies (FACS).
Journal of the Institute of Chemists PNG
The Institute publishes the Journal of the Institute of Chemists PNG, with the second volume published in 2009.
References
Chemistry societies
Chemistry education
Scientific organisations based in Papua New Guinea | The Institute of Chemists PNG | [
"Chemistry"
] | 97 | [
"Chemistry societies",
"nan",
"Chemistry organization stubs"
] |
65,656,240 | https://en.wikipedia.org/wiki/Statute%20of%20Sewers | The Statute of Sewers (23 Hen. 8. c. 5) was a 1532 law enacted by the English Reformation Parliament of King Henry VIII. It sought to make the powers of various commissions of sewers permanent, whereas previously, each parliament had to renew their powers.
It is noted as one of the earliest occurrences in English legal history of a Henry VIII power. The statute gave the commissions of sewers legislative powers, the power to impose taxation upon landowners, and the power to impose penalties for the non-payment of those taxes. Specifically, they could charge a rate on any person "who hath or holdeth any lands or tenements or common of pasture or profit of fishing or hath or may have any hurt loss or disadvantage" who lived within the area of responsibility of the Commissioners. This was the principle of benefit, and was challenged in the courts in 1609 at Keighley and the Isle of Ely. The courts on those occasions upheld the concept that rates could be levied for land that derived or would derive benefit, or had avoided or would avoid danger as a result of the work of the Commissioners. This principle was consistently upheld in the courts by a number of cases that were contested between 1788 and 1905, and remained the case until the passing of the Land Drainage Act 1930.
Although the act legitimised or created commissions of sewers for most of the areas of marshland within the country, Romney Marshes in Kent were specifically excluded, and the Lords, Bailiff and Jurats of Romney Marsh continued to operate as they had previously done.
The act was also intended to remove obstructions from rivers, such as mills, weirs and fish traps, with Thomas Cromwell, the king's chief minister at the time stating: "An Act that never weir nor water-mill shall hereafter be erected or made within this realm." The implementation of the act resulted in the destruction of large numbers of such structures between 1535 and 1539, with the king himself suffering a loss of income when his own mills and weirs were destroyed. The commission of sewers for Hampshire was set up on 28 January 1535, and demolition of mills on the River Itchen started in mid- or late-1535. The mayor and citizens of Winchester wrote to Cromwell in 1536 to express their thanks that young salmon were once again appearing in the river, and that areas of land which had previously been flooded were now dry. However, not everyone was keen on the measures, with the letter noting that the Bishop of Winchester was unhappy about the destruction of his installation at Woodmill, and that there was opposition to carrying out the objects of the act in Hampshire by "the great lords and their officials".
This approach was relatively short-lived, with officials at Hereford Cathedral and residents of the city asking Parliament to allow them to rebuild four mills in 1555, as their destruction had caused unemployment and poverty. Their request was granted, and the Bishop of Winchester's Woodmill was reconstructed around 1570.
References
Bibliography
Acts of the Parliament of England (1485–1603)
1532 in law
1532 in England | Statute of Sewers | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 634 | [
"Sewerage",
"Water pollution",
"Environmental engineering"
] |
65,656,348 | https://en.wikipedia.org/wiki/Wildlife%20endocrinology | Wildlife endocrinology is a branch of endocrinology which deals with the study of the endocrine system in vertebrates as well as invertebrates. It deals with hormone analysis which helps understand the basic physiological functions such as metabolic activity, reproduction, health and well-being of the organism. Hormones can be measured via multiple biological matrices such as blood, urine, faeces, hair and saliva, the choice of which depends upon the type of information required, ease of sample collection, assays available to analyse the sample and species difference in hormone metabolism and excretion. Non-invasive samples are preferred for wild ranging animals whereas, both invasive as well as non-invasive samples are used to study captive animals.
Background
Wildlife endocrinology can help understand the mechanisms by which organisms cope with changing environment and therefore plays an important role in wildlife conservation. Field endocrine strategies have progressed quickly as of late and can give considerable data on the growth, stress, and reproductive status of individual creatures, in this manner giving knowledge into current and future reactions of populations to changes in the earth. Ecological stressors and regenerative status can be recognized nonlethally by estimating various endocrine-related endpoints, like steroids for plasma, living and nonliving tissue, urine, and feces. Data on the natural or endocrine necessities of individual species for typical development, advancement, and multiplication will give basic data to species and environment preservation. For some taxa, essential data on endocrinology is missing, and progress in preservation endocrinology will require approaches that are both "fundamental" and "applied" and incorporate reconciliation of research center and field approaches.
Sampling methods in wildlife endocrinology
Sampling always depends upon the feasibility of the sampling protocol. If one is assessing the health of humans or captive, based on what kind of information one is seeking, sampling can change. In case of animals, it is easier to conduct blood sampling or collection of tissues from captive animals. Here one needs to be in closer contact with the target individual. But when working with wild animals, this might not be possible and thus other methods of sampling such as non-invasive sampling can be done. On the basis of invasiveness, there are two types of sampling.
Invasive sampling
Blood and tissue sampling is known to be invasive sampling. Invasive samples are difficult to collect but at the same time provide data about the current situation. DNA, hormone levels, infections and the overall health of the organism can all be tested from a single blood sample. Despite being advantageous for providing more information, most of the researchers prefer non-invasive sampling methods.
Non-invasive sampling
In the case of animals, such invasive sampling requires restraining or capture of the individual. Drawing blood or taking out tissues is still easier from captive animals but for wild animals, it becomes very difficult. The animal either needs to be trapped or tranquilized, which in many cases is logistically impossible for wild animals. Further, in case of cortisol measurement, restraining during blood sample collection may itself be a stressor and may potentially lead to increased levels of stress hormones. Thus, to overcome this, non-invasive sampling can be carried out which is easier to collect and does not harm the animals. Following are a few examples of non-invasive samples that can be collected from animal species, depending on the suitability of the sampling procedure:
● Hair
● Feathers
● Urine
● Saliva
● Fecal matter (FM)
Hair, urine, saliva and feces can be easily collected from captive as well as wild animals. This can be done in a majority of animal taxa including most of the reptiles, aves, mammals and amphibians
References
Endocrinology
Animal physiology | Wildlife endocrinology | [
"Biology"
] | 758 | [
"Animals",
"Animal physiology"
] |
65,657,913 | https://en.wikipedia.org/wiki/Spike%20response%20model | The spike response model (SRM) is a spiking neuron model in which spikes are generated by either a deterministic or a stochastic threshold process. In the SRM, the membrane voltage is described as a linear sum of the postsynaptic potentials (PSPs) caused by spike arrivals to which the effects of refractoriness and adaptation are added. The threshold is either fixed or dynamic. In the latter case it increases after each spike. The SRM is flexible enough to account for a variety of neuronal firing pattern in response to step current input. The SRM has also been used in the theory of computation to quantify the capacity of spiking neural networks; and in the neurosciences to predict the subthreshold voltage and the firing times of cortical neurons during stimulation with a time-dependent current stimulation. The name Spike Response Model points to the property that the two important filters and of the model can be interpreted as the response of the membrane potential to an incoming spike (response kernel , the PSP) and to an outgoing spike (response kernel , also called refractory kernel). The SRM has been formulated in continuous time and in discrete time. The SRM can be viewed as a generalized linear model (GLM) or as an (integrated version of) a generalized integrate-and-fire model with adaptation.
Model equations for SRM in continuous time
In the SRM, at each moment in time t, a spike can be generated stochastically with instantaneous stochastic intensity or 'escape function'
that depends on the momentary difference between the membrane voltage and the dynamic threshold .
The membrane voltage at time t is given by
where is the firing time of spike number f of the neuron, is the resting voltage in the absence of input, is the input current at time t − s and is a linear filter (also called kernel) that describes the contribution of an input current pulse at time t − s to the voltage at time t. The contributions to the voltage caused by a spike at time are described by the refractory kernel . In particular,
describes the time course of the action potential starting at time as well as the spike-afterpotential.
The dynamic threshold is given by
where is the firing threshold of an inactive neuron and describes the increase of the threshold after a spike at time . In case of a fixed threshold [i.e., =0], the refractory kernel should include only the spike-afterpotential, but not the shape of the spike itself.
A common choice for the 'escape rate' (that is consistent with biological data) is
where is a time constant that describes how quickly a spike is fired once the membrane potential reaches the threshold and is a sharpness parameter. For the threshold becomes sharp and spike firing occurs deterministically at the moment when the membrane potential hits the threshold from below. The sharpness value found in experiments is which that neuronal firing becomes non-neglibable as soon the membrane potential is a few mV below the formal firing threshold. The escape rate process via a soft threshold is reviewed in Chapter 9 of the textbook Neuronal Dynamics.
In a network of N SRM neurons , the membrane voltage of neuron is given by
where are the firing times of neuron j (i.e., its spike train), and describes the time course of the spike and the spike after-potential for neuron i, and describe the amplitude and time course of an excitatory or inhibitory postsynaptic potential (PSP) caused by the spike of the presynaptic neuron j. The time course of the PSP results from the convolution of the postsynaptic current caused by the arrival of a presynaptic spike from neuron j.
Model equations for SRM in discrete time
For simulations, the SRM is usually implemented in discrete time. In time step of duration , a spike is generated with probability
that depends on the momentary difference between the membrane voltage and the dynamic threshold . The function F is often taken as a standard sigmoidal with steepness parameter . But the functional form of F can also be calculated from the stochastic intensity in continuous time as where is the distance to threshold.
The membrane voltage in discrete time is given by
where is the discretized firing time of the neuron, is the resting voltage in the absence of input, and is the input current at time (integrated over one time step). The input filter and the spike-afterpotential are defined as in the case of the SRM in continuous time.
For networks of SRM neurons in discrete time we define the spike train of neuron j as a sequence of zeros and ones, and rewrite the membrane potential as
In this notation, the refractory kernel and the PSP shape can be interpreted as linear response filters applied to the binary spike trains .
Main applications of the SRM
Theory of computation with pulsed neural networks
Since the formulation as SRM provides an explicit expression for the membrane voltage (without the detour via a differential equations), SRMs have been the dominant mathematical model in a formal theory of computation with spiking neurons.
Prediction of voltage and spike times of cortical neurons
The SRM with dynamic threshold has been used to predict the firing time of cortical neurons with a precision of a few milliseconds. Neurons were stimulated, via current injection, with time-dependent currents of different means and variance while the membrane voltage was recorded. The reliability of predicted spikes was close to the intrinsic reliability when the same time-dependent current was repeated several times. Moreover, extracting the shape of the filters and directly from the experimental data revealed that adaptation extends over time scales from tens of milliseconds to tens of seconds. Thanks to the convexity properties of the likelihood in Generalized Linear Models, parameter extraction is efficient.
Associative memory in networks of spiking neurons
SRM0 neurons have been used to construct an associative memory in a network of spiking neurons. The SRM network which stored a finite number of stationary patterns as attractors using a Hopfield-type connectivity matrix was one of the first examples of attractor networks with spiking neurons.
Population activity equations in large networks of spiking neurons
For SRM neurons, an important variable characterizing the internal state of the neuron is the time since the last spike (or 'age' of the neuron) which enters into the refractory kernel . The population activity equations for SRM neurons can be formulated alternatively either as integral equations, or as partial differential equations for the 'refractory density'. Because the refractory kernel may include a time scale slower than that of the membrane potential, the population equations for SRM neurons provide powerful alternatives to the more broadly used partial differential equations for the 'membrane potential density'. Reviews of the population activity equation based on refractory densities can be found in as well in Chapter 14 of the textbook Neuronal Dynamics.
Spike patterns and temporal code
SRMs are useful to understand theories of neural coding. A network SRM neurons has stored attractors that form reliable spatio-temporal spike patterns (also known as synfire chains) example of temporal coding for stationary inputs. Moreover, the population activity equations for SRM exhibit temporally precise transients after a stimulus switch, indicating reliable spike firing.
4. History and relation to other models
The Spike Response Model has been introduced in a series of papers between 1991 and 2000. The name Spike Response Model probably appeared for the first time in 1993. Some papers used exclusively the deterministic limit with a hard threshold others the soft threshold with escape noise. Precursors of the Spike Response Model are the integrate-and-fire model introduced by Lapicque in 1907 as well as models used in auditory neuroscience.
SRM0
An important variant of the model is SRM0 which is related to time-dependent nonlinear renewal theory. The main difference to the voltage equation of the SRM introduced above is that in the term containing the refractory kernel there is no summation sign over past spikes: only the most recent spike matters. The model SRM0 is closely related to the inhomogeneous Markov interval process and to age-dependent models of refractoriness.
GLM
The equations of the SRM as introduced above are equivalent to Generalized Linear Models in neuroscience (GLM). In the neuroscience, GLMs have been introduced as an extension of the Linear-Nonlinear-Poisson model (LNP) by adding self-interaction of an output spike with the internal state of the neuron (therefore also called 'Recursive LNP'). The self-interaction is equivalent to the kernel of the SRM. The GLM framework enables to formulate a maximum likelihood approach applied to the likelihood of an observed spike train under the assumption that an SRM could have generated the spike train. Despite the mathematical equivalence there is a conceptual difference in interpretation: in the SRM the variable V is interpreted as membrane voltage whereas in the recursive LNP it is a 'hidden' variable to which no meaning is assigned. The SRM interpretation is useful if measurements of subthreshold voltage are available whereas the recursive LNP is useful in systems neuroscience where spikes (in response to sensory stimulation) are recorded extracellulary without access to the subthreshold voltage.
Adaptive leaky integrate-and-fire models
A leaky integrate-and-fire neuron with spike-triggered adaptation has a subthreshold membrane potential generated by the following differential equations
where is the membrane time constant and is an adaptation current number, with index k, is the resting potential and is the firing time of the neuron and the Greek delta denotes the Dirac delta function. Whenever the voltage reaches the firing threshold the voltage is reset to a value below the firing threshold. Integration of the linear differential equations gives a formula identical to the voltage equation of the SRM. However, in this case, the refractory kernel does not include the spike shape but only the spike-afterpotential. In the absence of adaptation currents, we retrieve the standard LIF model which is equivalent to a refractory kernel that decays exponentially with the membrane time constant .
External links
Spike Response Model, Chapter 6.4 of the textbook Neuronal Dynamics
'soft threshold' and escape noise, Chapter 9 of the textbook Neuronal Dynamics
Quasi-Renewal Theory Chapter 14 of the textbook Neuronal Dynamics.
Spike Response Model, from Scholarpedia
Reference section
Biophysics
Computational neuroscience
Neuroscience | Spike response model | [
"Physics",
"Biology"
] | 2,172 | [
"Neuroscience",
"Applied and interdisciplinary physics",
"Biophysics"
] |
65,657,946 | https://en.wikipedia.org/wiki/Iranian%20identity%20booklet | The Iranian identity booklet, also known as the (), is one of the identity documents issued in Iran. This identity document is in booklet format and issued to Iranian citizens at birth. The National Organization for Civil Registration of Iran is obliged to issue an identity booklet to every Iranian citizen.
Iranian citizens have two identity documents, namely the Iranian identity card, which contains the holder's national identity number, and the identity booklet, which contains more information.
To participate in elections in Iran, voters must present their identity booklet.
According to the Civil Registration Reform Law approved on 8 January 1985 in Iran, the cover and the first page of the identity booklet are adorned with the emblem of Iran.
History
According to the decision of the Iran's Cabinet of Ministers on 12 December 1918 during the Qajar era, the regulations for the establishment of the Civil Registry Office in the Ministry of Interior were prepared. The first Iranian identity booklet (then called ()) was issued on 25 December 1918 for a newborn girl named "Fatemeh Irani". In honour of this, the third day of Dey (23 or 24 December) has been named National Organization for Civil Registration Day in Iran.
From March 1925, according to the law, obtaining identity booklet was required for all Iranian citizens in the areas where the Civil Registry Office was established.
The identity booklet information
Each Iranian identity booklet must contain the following information:
Information about the holder
Name, Surname and Gender
Scanned photograph of the holder's face
Identity booklet number
National Identity Number
Birth date: day, month and year in format of Solar Hijri calendar and Islamic calendar
Place of birth: County, District, Administrative division, City, Village
Father's name and mother's name
National identity number or identity booklet number of parents
Place of birth of parents
Special field for registration of marriage and divorce and details about Spouse
Special field for children's names and specifications
Special field for registration of the holder's death
Document information
Consecutive and series number of the booklet
Date of document preparation: day, month and year in format of Solar Hijri calendar
Document preparation location: Area, County, District, Administrative division, City, Village
Name and surname of the document regulator; Signature of the issuing officer and stamp of the office
Special field for description (such as renaming)
Special field for multiplying stamps (such as the stamp of participation in Election)
Multiplying stamps
According to the Civil Registry law of Iran, only the following institutions are allowed to stamp on the identity booklet:
National Organization for Civil Registration of Iran
Marriage and divorce notaries offices
Embassies of Iran in other countries
Identification administration of the Law Enforcement Force of the Islamic Republic of Iran
Interpol
General Election Administration of the Ministry of Interior
Elimination of spouse name
It is possible to eliminate spouse's name after divorce under certain conditions in Iran.
Replacement
When a replacement copy of an identity booklet is issued, the centre of each new page is stamped with the word "duplicate" (, ) and a new date of issue is indicated.
Invalidation
The identity booklet is revoked in two conditions: one is renunciation of Iranian nationality law and the other is death.
See also
Iranian identity card
Driving licence in Iran
Iranian passport
Tajik passport (Shinosnoma, Tajik for Shenasnameh)
Identity documents in Iran
References
Bibliography
Council of Europe. Committee of Ministers (2005). Identity and Travel Documents and the Fight Against Terrorism: Recommendation Rec(2005)7.
Jane Caplan, John C. Torpey (2001). Documenting Individual Identity: The Development of State Practices in the Modern World. Princeton University
External links
Iran Civil Registration Law text
National Organization for Civil Registration (Iran) on GHDx
Iranian National Organization for Civil Registration news on TehranTimes
Iran among the best in Civil Registration and Vital Statistics
Genealogy
Personal identification
Iranian nationality law
Authentication methods in Iran
Identity documents of Iran | Iranian identity booklet | [
"Biology"
] | 782 | [
"Phylogenetics",
"Genealogy"
] |
65,658,717 | https://en.wikipedia.org/wiki/Simba%20Sleep | Simba Sleep Limited (also known as Simba) is a British online mattress group that was founded in 2015. It manufactures and sells mattresses, bedding and other sleep products in several countries, including the UK, Canada and China. Simba's retail partnerships include John Lewis and Argos in the UK and Sleep Country stores in Canada.
History
Simba Sleep was co-founded in 2015 in the UK by Steve Reid, James Cox and the McClements family. The name of the company was suggested by Cox as it was a pet name he used for his partner.
Within the first year of the company's launch, Simba Sleep sold its first hybrid mattress within the UK. The company designed the mattress after analysing body profiling data from 10 million people around the world, in conjunction with the Sleep to Live Institute, and manufactured it in a factory in Derby, England.
In March 2016, Simba raised £1 million in funding from investors including Sir John Hegarty, as well as Richard Reed, co-founder of Innocent Drinks, and Tom Teichman.
Simba's initial investment round was followed by its Series A raise of £5 million in October 2016, as investors looked to support the brands’ overseas growth in markets such as France and Canada. The company received a further £9 million investment in February 2017, before unveiling another £40 million injection of funds in November 2017. The Series B round was led by venture capital firm Atami Capital and included backers, such as Nigel Wray, chairman of Saracens rugby union club, and the Swiss private bank Lombard Odier.
In April 2017, Simba hired the Real Madrid and Wales international footballer Gareth Bale to lead a promotional campaign, which included the development of an airplane seat designed to maximise sleep.
The British businessman Allan Leighton succeeded Tom Teichman to become chairman of Simba Sleep in August 2018, while continuing to serve as chairman of The Co-operative Group.
After working with Gareth Bale, the company named England rugby player Maro Itoje in July 2019 as the star of its next UK marketing campaign, which included the launch of an app that monitors sleep patterns.
At the start of 2020, Simba became operational in nine countries across Europe, Asia, and North America and secured a further $24 million in investment from the American private equity firm Cartesian Capital.
Simba Sleep has agreed to modify its online sales practices following an investigation by the UK Competition and Markets Authority (CMA). The investigation, launched in December 2023, raised concerns that the company may have misled customers about price reductions and applied undue pressure to make quick purchases. As part of undertakings, Simba Sleep has pledged to ensure that any “was” price reflects a genuine prior sale of the product at that price. Also, clarify the use of countdown clocks on its website, specifying which products they apply to and ensuring they do not create a false sense of urgency or mislead consumers about pricing changes.
Products
Simba Sleep's standard mattress consists of five layers of foam and 2,500 conical springs, which allow it to be folded in two and vacuum-packed into a cardboard box. In October 2019, Simba Sleep launched a premium version of its regular hybrid mattress, which contained 5,000 springs.
Simba also launched a duvet containing Outlast, a technology that was originally developed for NASA to protect astronauts from temperature changes during space exploration. The company has since developed its own version of the technology, known as Stratos, which it uses in its duvets and pillows.
See also
Casper Sleep
Ecosa Group
References
External links
Official website
Business data for Simba Sleep: Bloomberg
Beds
British brands
Companies based in London
Mattress retailers of the United Kingdom | Simba Sleep | [
"Biology"
] | 765 | [
"Beds",
"Behavior",
"Sleep"
] |
65,658,742 | https://en.wikipedia.org/wiki/Astialakwa | Astialakwa , ) was a prehistoric and historic village built by the ancestral Puebloan people located within the Astialakwa Archeological District (FS-360, LA-1825), in an area now known as the Jemez Springs area of Northern New Mexico. The archeological area is on the National Register of Historic Places (ID# 84003010). The location is restricted from access.
Description
Astialakwa was a fortified pueblo village near Jemez Pueblo in the area that is now New Mexico. The village was built at the top of a nearly inaccessible ridge on an 800-foot high detached mesa (peñol), overlooking the Jemez creek. The people who lived in these villages spoke the Towa language, a Tanoan language.
Astialaka shares architectural similarities with the former pueblos of Patokwa and Boletsakwa which were centered on two large linear plazas surrounded by multiple rooms built in the characteristic "ladder-type" construction. Astialakwa differed in that there were no kivas, and the one-story walls were built of unhewn tuff blocks. The complex architectural remains indicate that this was a habitation as well as a refuge pueblo, containing many rooms, petroglyphs and other rock art, defensive walls, and agricultural areas. The periods of significance were 1500-1599 and between 1600 and 1649.
History
Historically, the Jemez people lived in seven or more pueblos before the conquest of Santa Fe de Nuevo Méjico in 1598 by Juan Oñate and his men. The Spaniards built missions and forced the Jemez people to abandon their historic homes and move to three settlements with missions: Astialakwa, Gyusiwa and Patoqua (Patokwa). In 1692, don Diego de Vargas reconquered Nuevo Mexico and in 1694 stormed the fortress of Astialakwa in a siege.
Battle of Astialakwa
The Battle of Astialakwa (also known as the Siege of Astialakwa) took place on July 24, 1694, when a group of 120 soldiers led by the Spanish governor don Diego de Vargas and their Keresan-speaking allied militia from the Zia, Santa Ana and San Felipe pueblos, waged war against the Jemez Pueblo indigenous peoples. Eighty-four Jemez people died in the battle, while 81 people escaped. Over three hundred and sixty Native women and children were taken prisoner by the Spanish soldiers. Seven people leapt to their death instead of being captured. After the battle, Vargas ordered the village to be "burned and reduced to ashes" after giving the sheep, goats, cattle and maize to his Keres allies. Some who escaped were taken in by the Diné peoples to the west.
The battle was in part retaliation for the Pueblo Revolt, when over 30 Pueblo villages made up of peoples speaking six languages banded together in a unified uprising against the Spanish colonialist forces; culminating in the death of 401 Spanish on August 10, 1680.
Descendants of the survivors of Astialakwa continue to dwell and share their culture at Jemez Pueblo not far from Guadalupe Mesa.
Gallery
Astialakwa Archeological District is located near Jemez Pueblo, NM, USA. Access to the site is restricted.
See also
Ancestral Puebloan dwellings
Pueblo
Ancestral Pueblo people
Tanoan languages
References
Further reading
Cordell, Linda S. Before Pecos: Settlement Aggregation at Rowe, New Mexico. Maxwell Museum of Anthropology Anthropologica Papers No. 6. University of New Mexico Press, Albuquerque. 1998
Creamer, Winifred. The Architecture of Arroyo Hondo Pueblo, New Mexico. Arroyo Hondo Archaeological Series 7. 1993
Kidder, Alfred Vincent. Pecos, New Mexico: Archaeological Notes. Papers of the Peabody Foundation for Archaeology 5. Phillips Academy, Andover. 1958
LeBlanc, Steven A. Prehistoric Warfare in the American Southwest. University of Utah Press, Salt Lake City. 1999
Noel Hume, Ivor. Archaeology: Handmaiden to History. North Carolina Historical Review Volume 41, No.2), pages 214-225. 1964
Sando, Joe S. Pueblo Nations: Eight Centuries of Pueblo Indian History. Clear Light Publishers, Santa Fe, pages 297. 1998
Ancestral Puebloans
Former populated places in New Mexico
Historical regions
Ruins on the National Register of Historic Places
Archaeological sites on the National Register of Historic Places in New Mexico
Fortifications
1694 disestablishments | Astialakwa | [
"Engineering"
] | 902 | [
"Fortifications",
"Military engineering"
] |
65,659,208 | https://en.wikipedia.org/wiki/NGC%203902 | NGC 3902 is an intermediate spiral galaxy in the constellation Leo. It was discovered on April 6, 1785, by William Herschel and observed on February 19, 1827, by John Herschel. It is estimated to be 180 to 185 million light-years away, and its redshift-independent distance estimates to about 185 to 240 million light-years. It is around 75,000 light-years in diameter.
NGC 3902 is one galaxy within the NGC 3902 group (or LGG 254), a group of galaxies in Leo; the other galaxies of which are NGC 3920, NGC 3944, UGC 6806 and UGC 6807.
References
Galaxies discovered in 1785
Intermediate spiral galaxies
3902
Leo (constellation)
036923 | NGC 3902 | [
"Astronomy"
] | 154 | [
"Leo (constellation)",
"Constellations"
] |
65,659,752 | https://en.wikipedia.org/wiki/Lm%CE%B1TX5 | LmαTX5 is an α-scorpion toxin which inhibits the fast inactivation of voltage-gated sodium channels. It has been identified through transcriptome analysis of the venom gland of Lychas mucronatus, also known as the Chinese swimming scorpion – a scorpion species which is widely distributed in Southeast Asia.
Etymology
LmαTX5 derives its name from Lychas mucronatus (Lm) and is an α-scorpion toxin (αTX).
Sources
LmαTX5 was identified in a transcriptome analysis of the venom gland of Lychas mucronatus.
For research purposes the toxin was produced in the Escherichia coli to allow further characterization.
Chemistry
LmαTX5 full peptide is 81 amino acids in length, which comprises a signal peptide of 19 amino acids, and has a molecular mass of 9.4 kDa. The mature LmαTX5 is 62 amino acids in length, tightly bound by four disulfide bridges (indicated by * in the sequence):
Lys-Lys-Asp-Gly-Tyr-Pro-Tyr-Asp-Asp-Lys-Glu-Cys*-Lys-Tyr-Asp-Cys**-Trp-Lys-Asn-Glu-Tyr-Cys***-Asn-Asp-Leu-Cys****-Lys-Lys-Lys-Lys-Gly-Glu-Ser-Gly-Tyr-Cys**-Tyr-Ala-Leu-Asn-Leu-Ser-Cys***-Tyr-Cys****-Tyr-Gly-Leu-Pro-Asp-Lys-Glu-Lys-Thr-Ser-Arg-Thr-Gly-Lys-Cys*-Arg-Gly
The predicted 3D-structure resembles a common cysteine-stabilized CSαβ structural motif for α-scorpion toxins consisting of a short-segmented α-helix coupled to a triple-stranded β-sheet, connected by four disulfide bridges forming loops. The similar functional residues in the conserved NC-domain (Tyr7, Lys10, Arg56, Arg61) and Core-domain (Trp17, Asn40) together with the common CSαβ structural motif and the amino acid length strongly relate LmaTX5 to other α-scorpion toxins that specifically target voltage-gated sodium channels. Moreover, LmαTX5 resembles LmαTX3 in length (i.e., 62 amino acids) and function (e.g., affecting predominantly mNav1.4 and hNav1.5 sodium channels).
Target
Pharmacological experiments showed that the recombinant LmαTX5 toxin targets voltage–gated sodium channel isoforms. LmαTX5 affects Nav1.5 (EC50 = 1.03 ± 0.43 μM) and Nav1.4 (EC50 = 4.53 ± 1.38 μM, mostly found in skeletal muscles), and moderately inhibits Nav1.7 (EC50 = 67.62 ± 2.31 μM, mostly found in peripheral nervous system), while Nav1.2 is hardly affected. Its pharmacological profile is quite similar to α-scorpion toxin LmαTX3.
Mode of action
LmαTX5 might be considered as a gating–modifier toxin that disables outward movement of the voltage sensor causing prolongation of sodium inward flow. The structural similarity of LmαTX5 to the α-scorpion toxin group suggests that LmαTX5 likely binds to neurotoxin receptor site 3 of sodium channels. This receptor site is located on the extracellular loop, connecting transmembrane segments S3 and S4 of domain IV, that plays the role of a voltage sensor by moving outwards during depolarization. The predicted inhibitory mechanism of LmαTX5 involves preventing conformational changes within the IVS4 that affects its outward movement, thus inhibiting sodium channel inactivation. Action potentials would become prolonged by the toxin. This action mechanism is expected based on the structure of the toxin, but still lacks experimental conformation. Similarly, based on homology, binding of LmαTX5 to the receptor site may be weakened by membrane depolarization.
Toxicity
Based on affected channel subtypes, LmαTX5 could be expected to cause cardiac arrhythmia, by altering action potential propagation through the heart resulting in severe cardiac rhythm impairment, and inhibition of action potential propagation in neurons and skeletal muscles leading to paralysis of the prey.
References
Toxins
Ion channel toxins
Scorpion toxins | LmαTX5 | [
"Environmental_science"
] | 1,039 | [
"Toxins",
"Toxicology"
] |
65,660,387 | https://en.wikipedia.org/wiki/Medical%20Women%27s%20Association%20of%20Nigeria | The Medical Women's Association of Nigeria (MWAN) is a Nigerian women's health organization that represents female doctors registered with the Medical and Dental Council of Nigeria (MDCN). The group's mission is to improve women's health in Nigeria through patient advocacy, including offering community health screening programs.
MWAN is affiliated with the Nigerian Medical Association and Medical Women's International Association (MWIA), and operates in 34 of the country's 36 states. 2019 president Joyce Barber handed over, on Saturday, 14 September 2019 to Dr. Mininim I. Oseji, who then emerged as the 22nd National President of the Association.
History
MWAN's founder, Dr. S. Oludayisi Oduntan, participated at the 1974 International MWIA Congress in Rio de Janeiro, and returned to Nigeria inspired to create her own national organization for female medical professionals in the Niger Delta. On 4 June 1975, MWAN met for the first time at the University College Hospital in Ibadan.
At the 1976 MWIA Congress in Tokyo, MWAN was formally enrolled with the international community. Three female doctors, Dr. Oludayisi Oduntan, Dr. Aderonke Manuwa-Olumide, and Dr. Modupe Onadeko, attended that particular Congress on behalf of what was then only a regional organisation.
Dr. Irene Ighodaro served as the first president, and its first bi-annual conference was held at the Lagos University Teaching Hospital on 19 May 1979.
Elected during the association's centennial triennial meeting in July 2019, MWAN past president Eleanor Nwadinobi (2007 - 2009 biennium) also served as president of the International body (MWIA), after the resignation of the president at the time.
In 2017, the organization reportedly screened 6,000 women for cervical cancer, with plans to screen 8,000 women annually.
References
External links
Official MWAN website
University of Pennsylvania. Genius without education is like Silver in the Mine
VNVA: The Dutch Society of Female Doctors
Jain S, Madani KS, Swaroop M. Inaugural Women in Medicine Summit: An Evolution of Empowerment in Chicago, Illinois, 20 and 21 September 2019: Event Highlights, Scientific Abstracts, and Dancing with Markers. Int J Acad Med [serial online] 2019 [cited 2 January 2021];5:240-301.
Organizations for women in science and technology
Organizations based in Nigeria | Medical Women's Association of Nigeria | [
"Technology"
] | 499 | [
"Organizations for women in science and technology",
"Women in science and technology"
] |
42,775,116 | https://en.wikipedia.org/wiki/Saccharomyces%20chevalieri | Saccharomyces chevalieri is the dominant species of yeast found in coconut palm wine fermentations. It is similar to Saccharomyces cerevisiae, but lacks the ability to ferment maltose (absent from the palm wine fermentation environment) and has been advanced as an intermediate to the development of S. cerevisiae. It appears to fill similar niche in fermenting simple sugars to ethanol in later fermentation.
References
Saccharomyces
Yeasts used in brewing
Fungi described in 1914
Fungus species | Saccharomyces chevalieri | [
"Biology"
] | 116 | [
"Fungi",
"Fungus species"
] |
42,777,505 | https://en.wikipedia.org/wiki/Protectin%20D1 | Protectin D1 also known as neuroprotectin D1 (when it acts in the nervous system) and abbreviated most commonly as PD1 or NPD1 is a member of the class of specialized proresolving mediators. Like other members of this class of polyunsaturated fatty acid metabolites, it possesses strong anti-inflammatory, anti-apoptotic and neuroprotective activity. PD1 is an aliphatic acyclic alkene 22 carbons in length with two hydroxyl groups at the 10 and 17 carbon positions and one carboxylic acid group at the one carbon position.
Specifically, PD1 is an endogenous stereoselective lipid mediator classified as an autocoid protectin. Autacoids are enzymatically derived chemical mediators with distinct biological activities and molecular structures. Protectins are signaling molecules that are produced enzymatically from unsaturated fatty acids. Their molecular structure is characterized by the presence of a conjugated system of double bonds. PD1, like other protectins, is produced by the oxygenation of the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) and it is found in many tissues, such as the retina, the lungs and the nervous system.
PD1 has a significant role as an anti-inflammatory, anti-apoptotic and neuroprotective molecule. Studies in Alzheimer's disease animal models, in stroke patients and in human retina pigment epithelial cells (RPE) have shown that PD1 can potentially reduce inflammation induced by oxidative stress and inhibit the pro-apoptotic signal, thereby preventing cellular degeneration. Finally, recent studies examining the pathogenicity of influenza viruses, including the avian flu (H5N1), have suggested that PD1 can potentially halt the proliferation of the virus, thus protecting respiratory cells from lethal viral infections.
Biosynthesis of PD1
In vivo, PD1 is mainly produced as a response to inflammatory signals and it is found in various tissues, such as the retina pigment epithelial cells, lung epithelial cells, peripheral blood mononuclear cells (PBMC) and neural tissues. Studies in PBMC have shown that endogenous DHA, the main precursor of PD1, is released by the activity of phospholipase A2. According to these studies, PD1 is preferentially synthesized in PBMC cells skewed to the Type 2 T helper cell phenotype (TH2). This suggests that T-cell differentiation plays an important role in the activation of the PD1 biosynthetic pathway. The interaction of PBMC with interleukin 4 (IL-4), a potent inflammatory signal, leads to the differentiation of PBMC to TH2 type lymphocytes. In addition, activated TH2 cells further release IL-4, leading to the up-regulation of the enzyme 15-lipoxygenase-1 (15-LO-1). 15-LO-1 is a non-heme iron-carrying dioxygenase that adds oxygen atoms in a stereospecific manner on free and esterified ω-3 polyunsaturated fatty acids like DHA. Overall, the biosynthesis of PD1 proceeds through three distinct steps throughout which the activity of 15-LO-1 is essential. In the first step of the biosynthetic pathway, the binding of 15-LO-1 to its substrate (DHA) leads to the formation of the (17S)-hydro(peroxy)-DHA intermediate. This intermediate is rapidly processed to form a 16(17)-epoxide-containing molecule, which is the second intermediate. Finally, in the third step of the pathway, enzymatic hydrolysis of the 16(17)-epoxide-containing intermediate leads to the formation of PD1.
Functions of PD1
In general, PD1 in vivo exhibits a potent anti-apoptotic and anti-inflammatory activity in the tissues in which it is localized. DHA, the main PD1 precursor, is mostly found in tissues such as the retinal synapses, photoreceptors, the lungs and the brain, suggesting that these tissues are more likely to be benefited from the protecting activity of PD1.
Activity of PD1 in the retina
RPE are essential in the survival and renewal of the photoreceptors in the retina. These cells exhibit a potent phagocytic activity that ensures the proper function of the retina. Therefore, oxidative stress can potentially damage the RPE cells and cause vision impairment. Studies in human RPE cells have suggested that the presence of oxidative stress triggering molecules, such as H2O2 causes the fragmentation of the DNA that in turn triggers apoptosis. These studies have proposed that PD1 acts as a signaling molecule and through its ligand-receptor interaction down-regulates the expression of genes, such as the transcription factor NF-κB. The inhibition of NF-κB results in the down-regulation of the pro-inflammatory gene COX-2 (cyclooxygenase-2) which is responsible for the release of prostaglandins, a potent pro-inflammatory mediator. In addition, PD1 has an important role in regulating the expression of the Bcl-2 family proteins (Bcl-2, Bcl-xL, Bax and Bad) that precedes the release of the cytochrome c complex from the mitochondria and the formation of the apoptosome. The presence of PD1 up-regulates the expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL, while it inhibits the expression of the pro-apoptotic proteins Bax and Bad. Specifically, PD1 regulates this protein family by promoting the dephosphorylation of Bcl-xL by protein phosphatase 2A (PP2A) at residue Ser-62 which in turn heterodimerizes with the pro-apoptotic protein Bax and inactivates it. Consequently, the activity of the Bcl-2 family proteins results in the inhibition of the caspase 3 enzyme, thus preventing apoptosis and promoting RPE cell survival.
Effects of PD1 in Alzheimer's disease
Among others, Alzheimer's disease is characterized by the reduced concentration of PD1 and by the increased concentration of the amyloid-β peptide (Aβ42) that is responsible for the formation of senile plaques and also induces inflammation and apoptosis in neuronal tissues. Aβ42 is generated by the enzymatic cleavage of the β-amyloid precursor protein (βΑPP) through β- and γ- secretases. Like other pro-inflammatory mediators, Aβ42 induces inflammation through the activation of the pro-inflammatory enzyme COX-2 and the release of prostaglandins. Moreover, the release of Aβ42 down-regulates the anti-apoptotic proteins Bcl-2 and Bcl-xL and up-regulates the pro-apoptotic proteins Bax and Bad that ultimately lead to the formation of the apoptosome. PD1 in human neuronal glial cells (HNG) has been shown to trigger the down-regulation of βΑPP, thus decreasing the Aβ42 content in neuronal tissues and reducing inflammation and apoptosis. Specifically, PD1 in Alzheimer's disease models has been shown to respond to the increased concentration of the pro-inflammatory molecule Aβ42 by binding and activating the peroxisome proliferator-activated receptor gamma (PPARγ) either directly or via other mechanisms. According to some models the activation of PPARγ leads to increased ubiquitination and degradation of βAPP, thus reducing the release of Aβ42. Furthermore, PD1 inhibits the production of Aβ42 peptide by down-regulating β-secretase-1 (BACE1), while up-regulating the α-secretase ADAM10 and the secreted amyloid precursor protein-α (sAPPα). Overall, the above mechanism leads to the cleavage of βAPP protein though a non-amyloidogenic pathway that halts the formation of Aβ42 and prevents the premature neuronal degeneration.
Antiviral activity of PD1
Studies in cultured human lung epithelial cells infected with the influenza virus H1N1 or H5N1 have found that endogenous production of PD1 decreases dramatically during infection due to the inhibition of 15-LO-1. Furthermore, the same studies have shown that in vivo administration of PD1 to H1N1 infected mice can potentially inhibit both the proliferation of the virus and the inflammation caused by the infection, thus increasing survival. PD1 protects against viral infections by disrupting the virus life cycle. Specifically, PD1 inhibits the binding of viral RNA to specific nuclear export factors in the host cells, thus blocking the export of viral RNA from the nucleus to the cytosol. The nuclear RNA export factor 1(NXF1) is of particular interest in the attenuation of viral infections via the activity of PD1. Specifically, the NXF1 transporter through its middle and C-terminal domains binds to the phenylalanine/glycine repeats in the nucleoporins (Nups) that line the nuclear pore. In the absence of PD1, influenza viral RNA binds to the NXF1 transporter that later binds specifically to Nup62 nucleoporin and exports the viral RNA into the cytosol. However, the administration of PD1 has shown that this lipid mediator specifically inhibits the binding of the viral RNA to NXF1, thus disrupting the proliferation of the virus.
Laboratory Synthesis of PD1
The large scale industrial production of PD1 is of great interest for pharmaceutical companies in order to harvest the potent anti-inflammatory and anti-apoptotic activities of this lipid mediator. So far, very few stereoselective laboratory syntheses of PD1 have been reported, but with a relatively low yield.
Convergent Stereoselective Synthesis
According to one method, PD1 is synthesized in 15% yield through an 8-step convergent stereoselective process. Initially, the alkyne, (Z)-3-tertbutyldimethylsiloxy-oct-5-en-1-yne reacts with bromo-E,E,Z,Z-tetraene ester in a Sonogashira cross-coupling reaction at room temperature in the presence of Pd-(PPh3)4 and CuI using diethylamine as a solvent which produces the bis-hydroxyl-protected methyl ester. Removal of the two tert-butyldimethylsilyl ethers (TBS-protecting groups) is attained with an excess of TBAF in THF at 0 °C which produces a diol containing a conjugated alkyne. The conjugated alkyne is reduced to the methyl ester. In addition, the diol is hydrogenated using the Lindlar catalyst, with 1-octene added as a sacrificial olefin, to produce a highly stereoselective triene, while water is eliminated from the diol through a Boland reduction. Finally, the methyl ester undergoes saponification at 0 °C with dilute LiOH (aq.) in methanol followed by acidic work-up with NaH2PO4 (aq.) in order to produce PD1.
Alternative Stereoselective Synthesis
Alternatively, PD1 laboratory synthesis proceeds through a different stereoselective method. Initially, hydroboration of a TBS-protected acetylene with Sia2BH produces a TBS-protected vinylborane. The TBS-protected vinylborane reacts with vinyliodide in the presence of a Pd-catalyst, sodium hydroxide (NaOH) and THF to produce a TBS-protected alcohol. Later treatment of the TBS-protected alcohol with TBAF removes the protecting group and produces a diol. Finally, the diol is hydrolyzed with LiOH in THF (aq.) to produce PD1.
Other PDs
22-hydroxy-NPD1
22-hydroxy-PD1 (22-OH-PD1; i.e. 10R,17S,20-trihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid) is an omega oxidation product of PD1 probably formed in cells by the action of an unidentified Cytochrome P450 omega hydroxylase (see specialized proresolving mediators#Protectins/neuroprotectins). While the omega oxidation of many bioactive fatty acid metabolites such as leukotriene B4, 5-HETE, 5-oxo-eicosatetraenoic acid (i.e. 5-oxo-ETE) results in a ~100-fold fall in their activity, the omega oxidized product of PD1 has been shown to possess potent ease exhibits potent anti-inflammatory and proresolving actions by inhibiting PMN chemotaxis in vivo and in vitro and decreased pro-inflammatory mediator levels in inflammatory exudates of an animal model at levels comparable to PD1.
Protectin DX
Protectin DX (PDX; i.e. 10S,17S-dihydroxy-4Z,7Z,11E,13Z,15E,19Z-docosahexaenoic acid) is the 13Z,15E,19Z isomer of NPD1 (which has the 13E,15Z,19Z double bond configuration)(see specialized proresolving mediators#Protectins/neuroprotectins). An early study mistakenly used PDX instead of PD1 in attributing anti-replicative and clinically beneficial effects in viral influenza disease in a mouse model to PD1. PDX also inhibits influx of circulating leukocytes into the peritoneum in a mouse model of inflammation. PDX has other anti-inflammatory actions. It inhibits COX-1 and COX-2 thereby blocking the formation of pro-inflammatory prostaglandins; it also inhibits the platelet-aggregating action of thromboxane A2 thereby blocking the platelet aggregations responses to agents that depend on platelets to release thromboxane A2.
Aspirin-triggered PD1
Aspirin-triggered PD1 (AT-PD1 or 17-epi-PD1: i.e. 10R,17R-dihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid) is the 10R-hydroxy isomer of PD1 (which has the 10S hydroxy residue) (see specialized proresolving mediators#Protectins/neuroprotectins). AT-PD1 has been shown to a) reduce the infiltration of neutrophils into the peritoneum in a mouse model of inflammatory disease; b) stimulate the Efferocytosis (i.e. engulfment and removal) of neutrophils; and c) reduce brain infarction and stroke in a rodent model.
10-epi-PD1
10-Epi-PD1 (ent-AT-NPD1: i.e. 10S,17S-Dihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid) is the 10S-hydroxy isomer of AT-PD1 (which has a 10R-hydroxy residue) (see specialized proresolving mediators#Protectins/neuroprotectins). 10-Epi-PD1 was detected in only a small amount in human PMN extracts but was more potent than PD1 or PDX in blocking the inflammatory response to zymosan A-induced murine acute peritonitis.
References
External links
Protectin D1 / PubChem Compound
Neuroprotectin D1 / Human Metabolome Database (HMDB)
Protectin D1 / Free chemical structure database (ChemSpider)
Neuroprotectin D1 / Food Component Database (FooDB)
Neuroprotectin D1 / Lipid Metabolites and Pathways Strategy (LIPID MAPS)
Alkene derivatives
Lipids
Fatty acids
Docosanoids | Protectin D1 | [
"Chemistry"
] | 3,515 | [
"Organic compounds",
"Biomolecules by chemical classification",
"Lipids"
] |
42,777,732 | https://en.wikipedia.org/wiki/J-multiplicity | In algebra, a j-multiplicity is a generalization of a Hilbert–Samuel multiplicity. For m-primary ideals, the two notions coincide.
Definition
Let be a local Noetherian ring of Krull dimension . Then the j-multiplicity of an ideal I is
where is the normalized coefficient of the degree d − 1 term in the Hilbert polynomial ; means the space of sections supported at .
References
Daniel Katz, Javid Validashti, Multiplicities and Rees valuations
Commutative algebra | J-multiplicity | [
"Mathematics"
] | 107 | [
"Fields of abstract algebra",
"Commutative algebra"
] |
42,777,908 | https://en.wikipedia.org/wiki/Prediction%20of%20crystal%20properties%20by%20numerical%20simulation | The prediction of crystal properties by numerical simulation has become commonplace in the last 20 years as computers have grown more powerful and theoretical techniques more sophisticated. High accuracy prediction of elastic, electronic, transport and phase properties is possible with modern methods.
Ab Initio Calculations
Ab initio or first principles calculations are any of a number of software packages making use of density functional theory to solve for the quantum mechanical state of a system. Perfect crystals are an ideal subject for such calculations because of their high periodicity. Since every simulation package will vary in the details of its algorithms and implementations, this page will focus on a methodological overview.
Basic theory
Density functional theory seeks to solve for an approximate form of the electronic density of a system. In general, atoms are split into ionic cores and valence electrons. The ionic cores (nuclei plus non-bonding electrons) are assumed to be stable and are treated as a single object. Each valence electron is treated separately. Thus, for example, a Lithium atom is treated as two bodies – Li+ and e- – while oxygen is treated as three bodies, namely O2+ and 2e−.
The “true” ground state of a crystal system is generally unsolvable. However, the variational theorem assures us that any guess as to the electronic state function of a system will overestimate the ground state energy. Thus, by beginning with a suitably parametrized guess and minimizing the energy with respect to each of those parameters, an extremely accurate prediction may be made. The question as to what one's initial guess should be is a topic of active research.
In the large majority of crystal systems, electronic relaxation times are orders of magnitude shorter than ionic relaxation times. Thus, an iterative scheme is adopted. First, the ions are considered fixed and the electronic state is relaxed by considering the ionic and electron-electron pair potentials. Next, the electronic states are considered fixed and the ions are allowed to move under the influence of the electronic and ion-ion pair potentials. When the decrease in energy between two iterative steps is sufficiently small, the structure of the crystal is considered solved.
Boundary conditions
A key choice that must be made is how many atoms to explicitly include in one's calculation. In Big-O notation, calculations general scale as O(N3) where N is the number of combined ions and valence electrons. For structure calculations, it is generally desirable to choose the smallest number of ions that can represent the structure. For example, NaCl is a bcc cubic structure. At a first guess, one might construct a cell of two interlocked cubes – 8 Na and 8 Cl – as one's unit cell. This will give the correct answer but is computationally wasteful. By choosing appropriate coordinates, one might simulate it with just two atoms: 1 Na and 1 Cl.
Crystal structure calculations rely on periodic boundary conditions. That is, the assumption is that the cell you have chosen is in the midst of an infinite lattice of identical cells. By taking our 1 Na 1 Cl cell and copying it many times along each of the crystal axes, we will have simulated the same superstructure as our 8 Na 8 Cl cell but with much reduced computational cost.
Raw output
Only a few lists of information will be output from a calculation, in general. For the ions, the position, velocity and net force on each ion are recorded at each step. For electrons, the guess as to the electronic state function may be recorded as well. Finally, the total energy of the system is recorded. From these three types of information, we may deduce a number of properties.
Calculable properties
Unit cell parameters
Unit cell parameters (a,b,c,α,β,γ) can be computed from the final relaxed positions of the ions. In a NaCl calculation, the final position of the Na ion might be (0,0,0) in picometer Cartesian coordinates and the final position of the Cl ion might be (282,282,282). From this, we see that the lattice constant would be 584 pm. For non-orthorhombic systems, the determination of cell parameters might be more complicated, but many ab-initio numerical packages have utilities to make this calculation simpler.
Once the lattice cell parameters are known, patterns for single crystal or powder diffraction can be readily predicted via Bragg's Law.
Temperature and pressure
The temperature of the system can be estimated by use of the Equipartition Theorem, with three degrees of freedom for each ion. Since ionic velocities are generally recorded at each step in the numerical simulation, the average kinetic energy of each ion is easy to calculate. There exist schemes which attempt to control the temperature of the simulation by, e.g. enforcing each ion to have exactly the kinetic energy predicted by the Equipartition Theorem (Berendsen thermostat) or by allowing the system to exchange energy and momentum with a (more massive) fictitious enclosing system (Nose-Hoover thermostat).
The net force on each ion is generally calculated explicitly at each numerical step. From this, the stress tensor of the system can be calculated and usually is calculated by the numerical package. By varying the convergence criteria, one can either seek a lowest energy structure or a structure that produces a desired stress tensor. Thus, high pressures can be simulated as easily as ambient pressures.
Elastic properties
The Young's modulus of a mineral can be predicted by varying one cell parameter at a time and observing the evolution of the stress tensor. Because the raw output of a simulation includes energy and volume, the integrated version of the Birch-Murnaghan equation of state is often used to determine bulk modulus.
Electronic density of states
The electronic density functional is explicitly used in the calculation of the electronic ground state. Packages such as VASP have an option to calculate the electronic density of states per eV to facilitate the prediction of conduction bands and band gaps.
Thermal transport properties
The Green-Kubo relations can be used to calculate the thermal transport properties of a mineral. Since the velocities of the ions are stored at each numerical step, one can calculate the time correlation of later velocities with earlier velocities. The integral of these correlations is related to the Fourier thermal coefficient.
Diffusion
By recording the ionic positions at each time step, one can observe how far, on average, each ion has moved from its original position. The mean squared displacement of each ion type is related to the diffusion coefficient for a particle undergoing Brownian motion.
References
Crystallography | Prediction of crystal properties by numerical simulation | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 1,349 | [
"Crystallography",
"Condensed matter physics",
"Materials science"
] |
42,777,911 | https://en.wikipedia.org/wiki/H%C3%A9non%E2%80%93Heiles%20system | While at Princeton University in 1962, Michel Hénon and Carl Heiles worked on the non-linear motion of a star around a galactic center with the motion restricted to a plane. In 1964 they published an article titled "The applicability of the third integral of motion: Some numerical experiments". Their original idea was to find a third integral of motion in a galactic dynamics. For that purpose they took a simplified two-dimensional nonlinear rotational symmetric potential and found that the third integral existed only for a limited number of initial conditions.
In the modern perspective the initial conditions that do not have the third integral of motion are called chaotic orbits.
Introduction
The Hénon–Heiles potential can be expressed as
The Hénon–Heiles Hamiltonian can be written as
The Hénon–Heiles system (HHS) is defined by the following four equations:
In the classical chaos community, the value of the parameter is usually taken as unity.
Since HHS is specified in , we need a Hamiltonian with 2 degrees of freedom to model it.
It can be solved for some cases using Painlevé analysis.
Quantum Hénon–Heiles Hamiltonian
In the quantum case the Hénon–Heiles Hamiltonian can be written as a two-dimensional Schrödinger equation.
The corresponding two-dimensional Schrödinger equation is given by
Wada property of the exit basins
Hénon–Heiles system shows rich dynamical behavior. Usually the Wada property cannot be seen in the Hamiltonian system, but Hénon–Heiles exit basin shows an interesting Wada property. It can be seen that when the energy is greater than the critical energy, the Hénon–Heiles system has three exit basins. In 2001 M. A. F. Sanjuán et al. had shown that in the Hénon–Heiles system the exit basins have the Wada property.
References
External links
http://mathworld.wolfram.com/Henon-HeilesEquation.html
Stellar astronomy
Chaotic maps | Hénon–Heiles system | [
"Astronomy",
"Mathematics"
] | 418 | [
"Functions and mappings",
"Stellar astronomy",
"Mathematical objects",
"Mathematical relations",
"Chaotic maps",
"Astronomical sub-disciplines",
"Dynamical systems"
] |
42,778,673 | https://en.wikipedia.org/wiki/Climatological%20normal | Climatological normal or climate normal (CN) is a 30-year average of a weather variable for a given time of year.
Most commonly, a CN refers to a particular month of year, but it may also refer to a broader scale, such as a specific meteorological season. More recently, CN have been reported for narrower scales, such as day of year and even hourly scale.
Climatological normals are used as an average or baseline to evaluate climate events and provide context for year-to-year variability. Normals can be calculated for a variety of weather variables including temperature and precipitation and rely on data from weather stations. Variability from the 30-year averages is typical and climate variability looks at the magnitude of extremes. Climatological standard normals are overlapping periods updated every decade: 1971–2000, 1981–2010, 1991–2020, etc.
The term "normal" first appeared in the literature by Heinrich Wilhelm Dove in 1840 and the concept was formalized by the International Meteorological Committee in 1872. The use of the 30-year period of normals began in 1935 with the 1901-30 period. The continued use of 30 year normals has increasingly been called into question due to substantial evidence that the stationarity of climate statistics can no longer be taken for granted due to climate change. This has led to alternative definitions such as "Optimal Climate Normal" and the "Hinge Fit" approach to supplement the standard 30 year normals which are still commonly used.
See also
Climate anomaly
Climatology
Seasonality
References
Climate and weather statistics | Climatological normal | [
"Physics"
] | 317 | [
"Weather",
"Physical phenomena",
"Climate and weather statistics"
] |
42,779,171 | https://en.wikipedia.org/wiki/GU%20Piscium%20b | GU Piscium b (GU Psc b) is a directly imaged planetary-mass companion orbiting the star GU Piscium, with an extremely large orbit of , and an apparent angular separation of 42 arc seconds. The planet is located at right ascension declination at a distance of .
Properties
An orbital revolution around its parent star (which is 1/3 the mass of the Sun) or "year", would take approximately 163,000 years to complete, considering a circular orbit with 2000 AU as the semi-major axis. It is a gas giant located in the constellation of Pisces, 155 light-years from the Solar System, and estimated to have a mass nine to thirteen times that of Jupiter, and a surface temperature of 1000 K.
It is a relatively young stellar system, part of the AB Doradus moving group of ca. 30 main stars created from the same molecular cloud less than 100 million years ago, and the only one found among the 90 stars of the group examined.
The spectral type was initially determined to be T3.5 ±1. This team also found that it is a weak binary candidate. A later work found it more similar to known tight binary T-dwarfs and assigned a spectral type of T2+T8. This object was found to be variable. First a study with the Canada-France-Hawaii Telescope found a rotation period of around 6 hours and an amplitude of 4 ±1% on 2014 October 11. On two other occasions this object was not variable. Later the variability was studied with Hubble Space Telescope WFC3 at 1.1-1.67 μm. GU Psc b showed variability with an amplitude of 2.7% and a rotation period of around 8 hours. The largely gray light curve modulation show that this object has heterogeneous clouds.
Discovery
The discovery was made by an international team of astronomers led by Marie-Eve Naud of the Université de Montréal in Quebec, combining observations from telescopes of the Gemini Observatory, the Mont Mégantic Observatory (OMM), the Canada–France–Hawaii Telescope (CFHT) and the W. M. Keck Observatory. Its large distance away from its parent star permitted the use of combined infrared and visible light images to detect it, a technique astronomers hope to reproduce to discover much closer planets with the Gemini Planet Imager (GPI) in Chile.
Near-infrared spectroscopy of the companion was obtained with the GNIRS spectrograph on the Gemini North Telescope, which shows evidence of low surface gravity confirming the planet's youth. Weak methane absorption was detected in H and K band corresponding to a spectral type of T3.5.
See also
List of exoplanet extremes
List of directly imaged exoplanets
CFBDSIR 2149−0403 - Possible rogue planet in the AB Doradus moving group
WD 0806−661 B
Notes
References
External links
IOPscience: DISCOVERY OF A WIDE PLANETARY-MASS COMPANION TO THE YOUNG M3 STAR GU PSC
arXiv: Discovery of a wide planetary-mass companion to the young M3 star GU Psc
NASA ADS: Discovery of a Wide Planetary-mass Companion to the Young M3 Star GU Psc
Exoplanets detected by direct imaging
Exoplanets discovered in 2014
Pisces (constellation) | GU Piscium b | [
"Astronomy"
] | 675 | [
"Pisces (constellation)",
"Constellations"
] |
42,779,263 | https://en.wikipedia.org/wiki/Pump%20inducer | An inducer is the axial inlet portion of a centrifugal pump rotor, the function of which is to raise the inlet head by an amount sufficient to prevent significant cavitation in the following pump stage. It is used in applications in which the inlet pressure of a pump is close to the vapor pressure of the pumped liquid. Inducers are frequently included in design of turbopumps for liquid propellant rocket engines, although they are used in other applications which require high suction performance. It does not increase NPSHa but decreases NPSHr for Pump.
Use in rocketry
In order to achieve high delta-v, the structural mass of a launch vehicle should be as low as possible. Liquid fuel tanks can be constructed lighter if the pressure within those tanks is kept low. Typically, for pump-fed rocket engines, the propellant tank pressures (and masses) are 1/10 to 1/40 of those in a pressure-fed rocket. The structural weight constraint also makes the rotating speed of the turbopump rotor as high as possible. For example, the rotating speed of the oxygen turbopump of the Japanese LE-7 rocket engine is 18300rpm. These two factors above combine to make the pump impeller very susceptible to cavitation. If cavitation occurs in the impeller, the performance of the pump will be severely degraded and the pump itself may be damaged.
References
Pumps
Rocket engines | Pump inducer | [
"Physics",
"Chemistry",
"Technology"
] | 289 | [
"Pumps",
"Turbomachinery",
"Engines",
"Rocket engines",
"Physical systems",
"Hydraulics",
"Fluid dynamics stubs",
"Fluid dynamics"
] |
42,779,491 | https://en.wikipedia.org/wiki/Le%20Bail%20method | Le Bail analysis is a whole diffraction pattern profile fitting technique used to characterize the properties of crystalline materials, such as structure. It was invented by Armel Le Bail around 1988.
Background
The Le Bail method extracts intensities (Ihkl) from powder diffraction data. This is done in order to find intensities that are suitable to determine the atomic structure of a crystalline material and to refine the unit cell and has the added advantage of checking phase-purity. Generally, the intensities of powder diffraction data are complicated by overlapping diffraction peaks with similar d-spacings. For the Le Bail method, the unit cell and the approximate space group of the sample must be predetermined because they are included as a part of the fitting technique. The algorithm involves refining the unit cell, the profile parameters, and the peak intensities to match the measured powder diffraction pattern. It is not necessary to know the structural factor and associated structural parameters, since they are not considered in this type of analysis. Le Bail can be used to find phase transitions in high pressure and temperature experiments. It generally provides a quick method to refine the unit cell, which allows better experimental planning. Le Bail analysis provides a more reliable estimate for the intensities of allowed reflections for different crystal symmetries.
Crystallographic structural determination can be accomplished in multiple ways. Le Bail technique is relevant for diffraction studies that involve using a radiation source, which may be neutron or synchrotron, to collect a high resolution, high quality powder diffraction profile. Initially, peak positions are found in the data. Next, the pattern is indexed in order to determine the unit cell or lattice parameters. Then, space group determination follows based on symmetry and the presence or absence of certain reflections. Then, either Le Bail or Pawley technique may be used to extract intensities and refine the unit cell.
Refinement
Le Bail analysis fits parameters using a steepest descent minimization process. Specifically, the method is least squares analysis, which is an iterative process that is discussed later in this article. The parameters being fitted include the unit-cell parameters, the instrumental zero error, peak width parameters, and peak shape parameters. First, the Le Bail method defines an arbitrary starting value for the intensities (Iobs). This value is ordinarily set to one, but other values may be used. While peak positions are constrained by the unit cell parameters, intensities are unconstrained. The equation to calculate intensities is:
In the equation, Iobs is the intensity observed at a particular step and yi(obs) is the observed profile point. yi(calc) is the A single intensity value may contain more than one peak. Other peaks may be calculated similarly. The final intensity for a peak is calculated as y(calc) = yi(1) + yi(2). The summation is carried out over all contributing profile points for a particular 2-theta bin. The summation process is known as profile intensity partitioning, and it works over any number of peaks. Le Bail technique works especially well with overlapping intensities since in this method the intensity is allotted based on the multiplicity of the intensities that contribute to a particular peak.
The somewhat arbitrary choice of starting values produces a bias in the calculated values. The refinement process continues by setting the new calculated structure factor to the observed structure factor value. The process is then repeated with the new structure factor estimate. At this point, the unit cell, background, peak widths, peak shape, and resolution function are refined, and the parameters are improved. The structure factor is then reset to the new structure factor value, and the process begins again. Structural refinement can continue with whole profile fitting techniques or further treatment of peak overlap. Probabilistic approaches may also be used to treat peak overlap.
Advantages
Some authors suggest the Le Bail technique exploits prior information more efficiently than Pawley method. This was an important consideration at the time of development when computing power was limited. Le Bail is also easily integrated into Rietveld analysis software, and is a part of a number of programs. Both methods improve subsequent structural refinements.
Available software
Le Bail analysis is commonly a part of Rietveld analysis software, such as GSAS/EXPGUI. It is also used in ARITVE, BGMN, EXPO, EXTRACT, FullProf, GENEFP, Jana2006, Overlap, Powder Cell, Rietan, TOPAS and Highscore.
References
Sources
Crystallography | Le Bail method | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 951 | [
"Crystallography",
"Condensed matter physics",
"Materials science"
] |
42,780,542 | https://en.wikipedia.org/wiki/USA-251 | USA-251, also known as GPS IIF-6, GPS SVN-67 and NAVSTAR 70, is an American navigation satellite which forms part of the Global Positioning System. It was the sixth of twelve Block IIF satellites to be launched.
Launch
Built by Boeing and launched by United Launch Alliance, USA-251 was launched at 00:03 UTC on 17 May 2014, atop a Delta IV carrier rocket, flight number D366, flying in the Medium+(4,2) configuration. The launch took place from Space Launch Complex 37B at the Cape Canaveral Air Force Station, and placed USA-251 directly into medium Earth orbit.
Orbit
As of 17 May 2014, USA-251 was in an orbit with a perigee of , an apogee of , a period of 729.22 minutes, and 55.04 degrees of inclination to the equator. It is used to broadcast the PRN 06 signal, and operates in slot 6 of plane D of the GPS constellation. The satellite has a design life of 15 years and a mass of .
It is currently in service following commissioning on June 10, 2014.
References
Spacecraft launched in 2014
GPS satellites
USA satellites
Spacecraft launched by Delta IV rockets | USA-251 | [
"Technology"
] | 249 | [
"Global Positioning System",
"GPS satellites"
] |
42,781,315 | https://en.wikipedia.org/wiki/Trumpler%202 | Trumpler 2 is an open cluster located in the constellation Perseus. It is approximately 2000 light-years from Earth, placing its position within the Perseus Arm of the Milky Way Galaxy. Although at this large distance, it can be seen with the naked eye, at magnitude 6.
It has a central red star named HD 16068 of spectral type K3.5II-III, and is visually the brightest star of the cluster as seen from Earth.
See also
NGC 957 - a nearby open cluster
References
External links
Open clusters
Perseus (constellation)
Trumpler catalog | Trumpler 2 | [
"Astronomy"
] | 121 | [
"Perseus (constellation)",
"Constellations"
] |
42,781,400 | https://en.wikipedia.org/wiki/Trumpler%203 | Trumpler 3 is an open cluster located in the constellation Cassiopeia. It has the visual magnitude of 7 and is one of the most famous star clusters in the Trumpler catalogue.
It has two bright stars, TYC 4053-658-1 and TYC 4053-466-1 of apparent magnitudes 10.16 and 10.02, respectively.
References
External links
Open clusters
Cassiopeia (constellation)
Trumpler catalog | Trumpler 3 | [
"Astronomy"
] | 94 | [
"Cassiopeia (constellation)",
"Constellations"
] |
42,781,587 | https://en.wikipedia.org/wiki/Zhaishan%20Tunnel | The Zhaishan Tunnel () is a tunnel in Jincheng Township, Kinmen County, Taiwan.
History
Construction of the tunnel started in 1961 and was completed on 22 March 1966, a few years after the Second Taiwan Strait Crisis in 1958 between the Republic of China Armed Forces and People's Liberation Army. Due to the lack of manpower and money to maintain the tunnel, it was closed and abandoned in 1986. Later on, there was growing interest in preserving the national heritage and remembering those who fought for Kinmen, thus on 23 May 1997, the Kinmen National Park took over the management of the tunnel. The tunnel was opened to the public in 1998.
Structures
The tunnel is in length, in width and in height. There are seven rooms inside that serve as barracks. The tunnel features an A-shaped waterway with 357 meters in length, 11.5 meters in width and 8 meters in height. It was used to conceal small naval vessels.
Activities
The tunnel has been the venue for the Kinmen Tunnel Music Festival since 2019.
See also
List of tourist attractions in Taiwan
Beihai Tunnel (Beigan)
Beihai Tunnel (Nangan)
Beihai Tunnel (Dongyin)
References
1966 establishments in Taiwan
Jincheng Township
Military history of Taiwan
Tunnels completed in 1966
Tunnels in Kinmen County
Tunnel warfare | Zhaishan Tunnel | [
"Engineering"
] | 262 | [
"Military engineering",
"Tunnel warfare"
] |
42,783,108 | https://en.wikipedia.org/wiki/Weighted%20projective%20space | In algebraic geometry, a weighted projective space P(a0,...,an) is the projective variety Proj(k[x0,...,xn]) associated to the graded ring k[x0,...,xn] where the variable xk has degree ak.
Properties
If d is a positive integer then P(a0,a1,...,an) is isomorphic to P(da0,da1,...,dan). This is a property of the Proj construction; geometrically it corresponds to the d-tuple Veronese embedding. So without loss of generality one may assume that the degrees ai have no common factor.
Suppose that a0,a1,...,an have no common factor, and that d is a common factor of all the ai with i≠j, then P(a0,a1,...,an) is isomorphic to P(a0/d,...,aj-1/d,aj,aj+1/d,...,an/d) (note that d is coprime to aj; otherwise the isomorphism does not hold). So one may further assume that any set of n variables ai have no common factor. In this case the weighted projective space is called well-formed.
The only singularities of weighted projective space are cyclic quotient singularities.
A weighted projective space is a Q-Fano variety and a toric variety.
The weighted projective space P(a0,a1,...,an) is isomorphic to the quotient of projective space by the group that is the product of the groups of roots of unity of orders a0,a1,...,an acting diagonally.
References
Algebraic geometry | Weighted projective space | [
"Mathematics"
] | 380 | [
"Fields of abstract algebra",
"Algebraic geometry"
] |
42,783,300 | https://en.wikipedia.org/wiki/Mu-Tron%20III | The Mu-Tron III is an envelope filter made by Musitronics Corporation. "The world's first envelope-controlled filter" was first made in 1972 by Mike Beigel and quickly became an essential effect for many funk musicians. It was produced again, in a modified version, in 2014.
Mu-tron III
Extracting elements from one of the prototypes of a synthesizer he was developing for Guild Guitar Company, Mike Beigel based the Mu-Tron III, at the instigation of Guild engineer Aaron Newman, on a prototype called the Timbre Generator. The Mu-tron III could be used for any number of electric instruments. Beigel said he chose the envelope-controlled filter over other synthesizer elements, such as ring modulation, because it sounded more musical; it was a more general effect that would lend itself to a variety of applications, and it was easy to use.
The Mu-tron III was an instant success and was used by jazz/fusion guitarist Larry Coryell, Funkadelic bass player Bootsy Collins (for his "Space Bass"), guitarist Jerry Garcia, Yes bassist Chris Squire, and Stevie Wonder, who used it on his Clavinet for the song "Higher Ground".
Beigel was successfully granted a patent for the circuitry of the Mu-tron III. Musitronics licensed the Mu-tron III circuitry to a few different companies in the seventies – the Univox Funky Filter and Monacor Effectmatic are notable examples.
The original Mu-tron III ran on 18V, using two 9V batteries; this gave it a wider dynamic range and more headroom compared to effects that ran on 9 volt. There was an optional power supply (the PS-1), and with later versions had built-in AC power supplies. The Mu-tron III used opto-isolators to control the filter, which was novel for the time, a method would also be used for the Mu-tron Phasor II and Bi-Phase. The state variable filter in the Mu-tron III allowed for low-pass, bandpass, and high-pass filter response, which could be triggered from low to high or vice versa. When ARP Instruments bought Musitronics in ‘79, they made the Mu-tron line for about a year before going out of business, and the Mu-tron III was no more. With the advent of the stompbox revival of the nineties, the Mu-tron III became one of the big-ticket items for collectors and players alike. There was a reissue of sorts, the HAZ Mu-tron III+, but Beigel says this (and other clones) did not have "the same magic".
In early 1995, however, Beigel did lend his expertise to Electro-Harmonix, creating an update of his original design, the Electro-Harmonix Q-Tron, and he also designed a Bi-Filter for E-H. Three other pedals, the Mini Q-Tron, Micro Q-Tron and Q-Tron+, are available from EHX as well, who now also offer the Bi-Filter, a modern version of Beigel Sound Lab's Envelope Controlled Filter, made in 1979. Michael Dregni, in Vintage Guitar, noted that none of the "clones, copycats, and other attempts to bring it back...sounded quite like the real deal". But in 2014, a renewed version of the Mu-Tron III, now called the Tru-Tron 3X, was made by Beigel's new company Mu-FX.
Tru-Tron 3X
The Tru-Tron can work "exactly like the original", but has added functionality and range, and is "smaller and more robust" than the original. It runs on 12 volts. In addition to the original's ability to control the upsweep of notes it adds control over the downsweep, and offers more gain for more intense effects. It also has an internal potentiometer which allows the user to adjust the envelope filter's response time to match the player's style.
References
External links
Mu-tron.org maintained by Mike Beigel, founder of Musitronics
Beigel Technology Corporation
Electro-Harmonix envelope filters
Effects units
Signal processing filter | Mu-Tron III | [
"Chemistry"
] | 901 | [
"Filters",
"Signal processing filter"
] |
42,783,634 | https://en.wikipedia.org/wiki/Penicillium%20amaliae | Penicillium amaliae is a fungus species of the genus of Penicillium. Penicillium amaliae is named after Catharina-Amalia Beatrix Carmen Victoria.
See also
List of Penicillium species
References
Further reading
amaliae
Fungi described in 2013
Fungus species | Penicillium amaliae | [
"Biology"
] | 64 | [
"Fungi",
"Fungus species"
] |
42,783,768 | https://en.wikipedia.org/wiki/Orthanilic%20acid | Orthanilic acid (2-aminobenzenesulfonic acid) is a biological acid with roles in benzoate degradation and microbial metabolism in diverse environments.
Orthanilic acid promotes reverse turn formation in peptides, inducing a folded conformation when incorporated into peptide sequences (Xaa-SAnt-Yaa), showing robust 11-membered-ring hydrogen-bonding.
Orthanilic acid is a structural component of some azo dyes which consequently have poor bacterial degradation.
Orthanilic acids have also been found to affect cardiac tension.
References
Benzenesulfonic acids
Amino acid derivatives
Anilines | Orthanilic acid | [
"Chemistry"
] | 130 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
42,783,850 | https://en.wikipedia.org/wiki/ANSI%20834%20Enrollment%20Implementation%20Format | The X12 834 EDI Enrollment Implementation Format is a standard file format in the United States for electronically exchanging health plan enrollment data between employers and health insurance carriers.
The Health Insurance Portability and Accountability Act (HIPAA) requires that all health plans or health insurance carriers accept a standard enrollment format: ANSI 834A Version 5010.
An 834 file contains a string of data elements, with each representing a fact, such as a subscriber’s name, hire date, etc. The entire string is called a transaction set.
The 834 is used to transfer enrollment information from the sponsor of the insurance coverage, benefits, or policy to a payer. The format attempts to meet the health care industry's specific need for the initial enrollment and subsequent maintenance of individuals who are enrolled in insurance products.
Layout
An example layout of an X12 834 Version 005010 file is shown below. Each line starts with a code to identify the type of data that follows, with individual pieces of data separated by an asterisk. The tilde indicates the end of that section.
INS*Y*18*030*XN*A*E**FT~
REF*0F*152239999~
REF*1L*Blue~
DTP*336*D8*20070101~
NM1*IL*1*BLUTH*LUCILLE****34*152239999~
N3*224 N DES PLAINES*6TH FLOOR~
N4*CHICAGO*IL*60661*USA~
DMG*D8*19720121*F*M~
HD*030**VIS**EMP~
DTP*348*D8*20111016~
INS*N*19*030*XN*A*E***N*N~
REF*0F*152239999~
REF*1L*Blue~
DTP*357*D8*20111015~
NM1*IL*1*BLUTH*BUSTER~
N3*224 N DES PLAINES*6TH FLOOR~
N4*CHICAGO*IL*60661*USA~
DMG*D8*19911015*M~
HD*030**VIS~
DTP*348*D8*20110101~
DTP*349*D8*20111015~
See also
X12 Document List
References
EDI 834 Benefit Enrollment and Maintenance
Guardian Electronic User Guide 834 Enrollment and Maintenance
Data management
Computer file formats
Health insurance in the United States
American National Standards Institute standards | ANSI 834 Enrollment Implementation Format | [
"Technology"
] | 537 | [
"American National Standards Institute standards",
"Computer standards",
"Data",
"Data management"
] |
42,784,181 | https://en.wikipedia.org/wiki/CollecTF | CollecTF is a database of transcription factor binding sites in the Bacteria domain.
CollecTF compiles only experimentally validated TF-binding sites. This is accomplished through the manual curation of peer-reviewed literature with a special focus on the experimental process used to identify TF-binding sites.
CollecTF entries are periodically submitted to NCBI for integration into RefSeq complete genome records as link-out features, maximizing the visibility of the data and enriching the annotation of RefSeq files with regulatory information. Seeking to facilitate comparative genomics and machine-learning analyses of regulatory interactions, in its initial release CollecTF provides domain-wide coverage of two TF families (LexA and Fur), as well as extensive representation for a clinically important bacterial family, the Vibrionaceae.
References
External links
http://collectf.umbc.edu
Biological databases | CollecTF | [
"Biology"
] | 185 | [
"Bioinformatics",
"Biological databases"
] |
42,784,415 | https://en.wikipedia.org/wiki/AMS%20Centennial%20Fellowship | The AMS Centennial Research Fellowship is presented annually to outstanding mathematicians who have held the doctoral degree for between three and twelve years. The primary selection criterion is excellence in research achievement.
A Research Fellowship Fund was established by the American Mathematical Society in 1973.
Previous awards
2023 - 2024 Joel Nagloo
2022 - 2023 Mimi Dai
2021 - 2022 Aaron J Pollack
2020 - 2021 Ilya Khayutin
2019 - 2020 Piotr Przytycki
2018 - 2019 Nguyen, Toan
2017 - 2018 Takeda, Shuichiro
2016 - 2017 Lubetzky, Eyal
2015 - 2016 Schnell, Christian; Lee, Kyungyong
2014 - 2015 Juschenko, Kate
2013 - 2014 Zhu, Xinwen
2012 - 2013 Melnick, Karin
2011 - 2012 Toms, Andrew
2010 - 2011 Bellaiche, Joel
2009 - 2010 Montalban, Antonio
2008 - 2009 Hoffman, Christopher
2007 - 2008 Kassabov, Martin
2006 - 2007 Hacon, Christopher; Kra, Bryna
2005 - 2006 Lee, Yuan-Pin; Popa, Mihnea
2004 - 2005 Baik, Jinho; Kitchloo, Nitu
2003 - 2004 Kim, Henry; Meier, John
2002 - 2003 Fannjiang, Albert; Gan, Wee Teck; Ramakrishna, Ravi
2001 - 2002 Dimitrov, Ivan; Vakil, Ravi; Wu, Jiahong; Zhu, Meijun
2000 - 2001 Fu, Siqi; Herald, Christopher; Ruan, Wei-Dong; Strela, Vasily
1999 - 2000 Rezk, Charles; Wang, Bin; Wang, Changyou; Yang, Tonghai
1998 - 1999 de Cataldo, Mark; Garoufalidis, Stavros; Kovács, Sándor; Li, Yanguang
1997 - 1998 Costin, Ovidiu; Diamond, Fred; Liu, Gang; Shen, Zhongwei;
1996 - 1997 Hu, Yi; McCann, Robert; Voronov, Alexander; Wang, Jiaping
1995 - 1996 de la Llave, Rafael; McCallum, William Gordon; Orr, Kent
1994 - 1995 Bauman, Patricia; Marker, David
1993 - 1994 Hurtubise, Jacques; Scedrov, Andre; Webb, David
1992 - 1993 Burdzy, Krzysztof; William Menasco; David Morrison
1991 - 1992 Bump, Daniel; Vilonen, Kari
1990 - 1991 Anderson, Michael; Gordon, Carolyn; Mitchell, Steven
1989 - 1990 Efrat, Isaac; Lee, John; Spatzier, Ralf
1988 - 1989 Bell, Steven; Blasius, Don; Gabai, David
1987 - 1988 Hain, Richard; Jacob, Bill
1986 - 1987 Ramakrishnan, Dinakar
1985 - 1986 Beals, Michael
1984 - 1985 Durrett, Richard
1983 - 1984 Lyons, Russell
1982 - 1983 Kuhn, Nicholas
1981 - 1982 Ein, Lawrence; Williams, Mark
1980 - 1981 Lazarsfeld, Robert; Parker, Thomas; Sachs, Robert
1979 - 1980 Brown, Scott; Hoffstein, Jeffrey; Kahn, Jeffry; McClure, James; Smith, Rick
1978 - 1979 Dankner, Alan; Harbater, David; Hiller, Howard; Kerckhoff, Steven; McOwen, Robert
1977 - 1978 Kalikow, Steven; Patton, Charles; Phong, Duong-Hong; Vogan, David
1976 - 1977 Ancel, Fredric; Sgro, Joseph
1975 - 1976 Gaffney, Terence; Nèvai, Paul; Reed, George
1974 - 1975 Abramson, Fred; Wang, James Li-Ming
See also
List of mathematics awards
References
Centennial Fellowship
Fellowships
Research awards
1974 establishments in the United States | AMS Centennial Fellowship | [
"Technology"
] | 767 | [
"Science and technology awards",
"Research awards"
] |
42,785,451 | https://en.wikipedia.org/wiki/Brzozowski%20derivative | In theoretical computer science, in particular in formal language theory, the Brzozowski derivative of a set of strings and a string is the set of all strings obtainable from a string in by cutting off the prefix . Formally:
.
For example,
The Brzozowski derivative was introduced under various different names since the late 1950s.
Today it is named after the computer scientist Janusz Brzozowski who investigated its properties and gave an algorithm to compute the derivative of a generalized regular expression.
Definition
Even though originally studied for regular expressions, the definition applies to arbitrary formal languages.
Given any formal language over an alphabet and any string , the derivative of with respect to is defined as:
The Brzozowski derivative is a special case of left quotient by a singleton set containing only : .
Equivalently, for all :
From the definition, for all :
since for all , we have
The derivative with respect to an arbitrary string reduces to successive derivatives over the symbols of that string, since for all :
A language is called nullable if and only if it contains the empty string . Each language is uniquely determined by nullability of its derivatives:
A language can be viewed as a (potentially infinite) boolean-labelled tree (see also tree (set theory) and infinite-tree automaton). Each possible string denotes a node in the tree, with label true when and false otherwise. In this interpretation, the derivative with respect to a symbol corresponds to the subtree obtained by following the edge from the root. Decomposing a tree into the root and the subtrees corresponds to the following equality, which holds for every language :
Derivatives of generalized regular expressions
When a language is given by a regular expression, the concept of derivatives leads to an algorithm for deciding whether a given word belongs to the regular expression.
Given a finite alphabet A of symbols, a generalized regular expression R denotes a possibly infinite set of finite-length strings over the alphabet A, called the language of R, denoted L(R).
A generalized regular expression can be one of the following (where a is a symbol of the alphabet A, and R and S are generalized regular expressions):
"∅" denotes the empty set: L(∅) = {},
"ε" denotes the singleton set containing the empty string: L(ε) = {ε},
"a" denotes the singleton set containing the single-symbol string a: L(a) = {a},
"R∨S" denotes the union of R and S: L(R∨S) = L(R) ∪ L(S),
"R∧S" denotes the intersection of R and S: L(R∧S) = L(R) ∩ L(S),
"¬R" denotes the complement of R (with respect to A*, the set of all strings over A): L(¬R) = A* \ L(R),
"RS" denotes the concatenation of R and S: L(RS) = L(R) · L(S),
"R*" denotes the Kleene closure of R: L(R*) = L(R)*.
In an ordinary regular expression, neither ∧ nor ¬ is allowed.
Computation
For any given generalized regular expression R and any string u, the derivative u−1R is again a generalized regular expression (denoting the language u−1L(R)).
It may be computed recursively as follows.
Using the previous two rules, the derivative with respect to an arbitrary string is explained by the derivative with respect to a single-symbol string a.
The latter can be computed as follows:
Here, is an auxiliary function yielding a generalized regular expression that evaluates to the empty string ε if R 's language contains ε, and otherwise evaluates to ∅. This function can be computed by the following rules:
Properties
A string u is a member of the string set denoted by a generalized regular expression R if and only if ε is a member of the string set denoted by the derivative u−1R.
Considering all the derivatives of a fixed generalized regular expression R results in only finitely many different languages. If their number is denoted by dR, all these languages can be obtained as derivatives of R with respect to strings of length less than dR. Furthermore, there is a complete deterministic finite automaton with dR states that recognises the regular language given by R, as stated by the Myhill–Nerode theorem.
Derivatives of context-free languages
Derivatives are also effectively computable for recursively defined equations with regular expression operators, which are equivalent to context-free grammars. This insight was used to derive parsing algorithms for context-free languages.
Implementation of such algorithms have shown to have cubic time complexity,
corresponding to the complexity of the Earley parser on general context-free grammars.
See also
Quotient of a formal language
References
Formal languages | Brzozowski derivative | [
"Mathematics"
] | 1,008 | [
"Formal languages",
"Mathematical logic"
] |
67,121,563 | https://en.wikipedia.org/wiki/Needleless%20connector | In medicine, a needleless connector connects to the end of vascular catheters and enable catheter access for infusion and aspiration. Needleless connectors (also known as NC's) were developed to reduce needlestick injuries, which occurs when the skin is accidentally punctured by a used needle. Needlestick injuries can be very serious and potentially expose a healthcare professional to bloodborne infectious diseases such as HIV/AIDS, Hepatitis B and Hepatitis C.
The needless connector should provide safe access to the catheter without the use of needles and enable the following:
Minimize catheter occlusion risk.
Allow for easy and effective decontamination between each use to prohibit microbial entry e.g. via a flat surface which is flush with the housing.
Before utilizing a needleless connector, it is important to properly disinfect the device to help prevent central line–associated bloodstream infection.
Various designs for the needless connector and its components have been developed over the years. This includes a patent developed by Karl Leinsing for "needleless connector" which relates generally to connectors of the type used in the handling and administration of parenteral fluids, and more particularly, to a valve mechanism incorporated within such connector for~~enabling a fluid interconnection to be made therewith without the use of a sharp cannula.
See also
Medical device
French catheter scale
Gastrostomy
G-Tube
Jejunostomy
Stent
References | Needleless connector | [
"Biology"
] | 301 | [
"Medical devices",
"Medical technology"
] |
67,121,636 | https://en.wikipedia.org/wiki/Tetraethylammonium%20diiron%20oxyhexachloride | Tetraethylammonium diiron oxyhexachloride is the chemical compound with the formula (N(C2H5)4)2Fe2OCl6. It is the tetraethylammonium salt of [Fe2OCl6]2-. Many related salts of [Fe2OCl6]2- are known. The anion consists of a pair of tetrahedral Fe(III) centers that share a oxo bridging ligand. The salt can be prepared by treatment of tetraethylammonium tetrachloroferrate with sodium trimethylsiloxide.
References
Chlorides
Iron(III) compounds
Metal halides
Coordination complexes
Tetraethylammonium salts | Tetraethylammonium diiron oxyhexachloride | [
"Chemistry"
] | 153 | [
"Chlorides",
"Inorganic compounds",
"Coordination complexes",
"Coordination chemistry",
"Salts",
"Metal halides"
] |
67,123,303 | https://en.wikipedia.org/wiki/Sodium%20trimethylsiloxide | Sodium trimethylsiloxide is an organosilicon compound with the formula NaOSi(CH3)3. It is the sodium salt of the conjugate base derived from trimethylsilanol. A white solid, its molecular structure consists of a cluster with Na-O-Na linkages on the basis of closely related compounds.
The salt is used to prepare trimethylsiloxide complexes by salt metathesis. Trimethylsiloxide is a lipophilic pseudohalide.
It is a source of oxide dianion.
Related compounds
Sodium silox, NaOSi(tBu)3 (tBu = C(CH3)3)
Potassium trimethylsilanolate
References
Trimethylsilyl compounds
Sodium compounds | Sodium trimethylsiloxide | [
"Chemistry"
] | 156 | [
"Functional groups",
"Trimethylsilyl compounds"
] |
67,123,375 | https://en.wikipedia.org/wiki/Vaccine%20line%20jumping | Vaccine line jumping is the act of obtaining a vaccine in which the supply fails to meet the demands of the population ahead of those for whom it has been prioritized, usually via fraudulent means, the exploitation of one's social status, or some other unethical manner. Vaccine line jumping is distinct from vaccine chasing, in which one goes out of their way to seek a scarcely available vaccine to which they are legally entitled.
In some situations, an honor system is used in which the recipient declares, either verbally or in writing, if they are in a priority group, but no proof is asked. Other places require that one who is in a priority group provide documentation of belonging to such a group. For example, if prioritization is by age, a driver's license or other governmental identification can be used to verify age. If by occupation, a work ID can be used, and if a medical condition is a criterion, it could be a physician certificate.
Methods
Vaccine line jumpers sometimes exaggerate a factor that could include them in a priority group, such as a category of employment or medical condition. For example, a medical administrative worker who has no contact with patients might consider themselves a "healthcare worker", or one who has had a bout of pneumonia might classify themselves as having had "lung disease", even as their condition is not chronic.
Sometimes, a glitch in the registration system can enable those who do not belong to a priority group to register and obtain a shot. Some people can obtain shots ahead of what is considered to be their turn because of their wealth or connections.
References
Vaccination
Public health
COVID-19 vaccines | Vaccine line jumping | [
"Biology"
] | 338 | [
"Vaccination"
] |
67,124,064 | https://en.wikipedia.org/wiki/National%20Centre%20for%20the%20Replacement%2C%20Refinement%20and%20Reduction%20of%20Animals%20in%20Research | The National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs, pronounced as "N C 3 Rs") is a British organization with the goal of reducing the number of animals used in scientific research. It is named after the three Rs principles, first described in 1959, for reducing the scale and impact of animal research. It was established in 2004 after the publication of a 2002 House of Lords select committee report on Animals In Scientific Procedures , the chief executive of NC3Rs is Dr Vicky Robinson, who was appointed CBE in the 2015 Birthday Honours "For services to Science and Animal Welfare".
See also
ARRIVE guidelines
References
External links
Animal testing
Animal welfare
Bioethics
Bioethics research organizations | National Centre for the Replacement, Refinement and Reduction of Animals in Research | [
"Chemistry",
"Technology"
] | 147 | [
"Bioethics",
"Animal testing",
"Ethics of science and technology"
] |
67,124,135 | https://en.wikipedia.org/wiki/Tetraethylammonium%20tetrachloronickelate | Tetraethylammonium tetrachloronickelate is the chemical compound with the formula (N(C2H5)4)2NiCl4. It is the tetraethylammonium salt of the blue-colored tetrahedral anion [NiCl4]2-. Several tetrachloronickelate salts are known. They are paramagnetic.
References
Chlorides
Nickel complexes
Metal halides | Tetraethylammonium tetrachloronickelate | [
"Chemistry"
] | 91 | [
"Chlorides",
"Inorganic compounds",
"Metal halides",
"Salts"
] |
67,124,137 | https://en.wikipedia.org/wiki/ARRIVE%20guidelines | The ARRIVE guidelines (short for Animals in Research: Reporting In Vivo Experiments) are a set of guidelines for improving experimental design and reporting standards for animal research, drawn up by the National Centre for the Replacement, Refinement and Reduction of Animals in Research. First published in 2010 as a checklist of 20 items, a revision, titled ARRIVE 2.0, was published in 2020 as two checklists of 10 "essential" items and 11 "recommended" items. While the guidelines have been endorsed by over a thousand scientific journals, their adoption and enforcement has remained limited.
Origin
A 2009 review of the quality of experimental design, analysis, and reporting methods of animal research conducted by the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) found that most biomedical journals were providing little or no guidance on how animal research should be analyzed and reported, outside of ethical guidelines for experimental design, such as the Three Rs. Additionally, it found issues with the way animal research is reported, with large proportions of articles not stating a hypothesis or objective of the study, lacking specifics about the characteristics of the animals used, not having used techniques such as randomization or blinding to reduce experimental bias, and not fully describing statistical methodology or providing measures of the precision or variability of the results. Additionally, while other fields had existing reporting guidelines for reducing methodological and statistical biases and improving reproducibility, such as MIAME, PRISMA, and the CONSORT statement, no such guidelines existed for animal studies.
In response, NC3Rs put together a working group to develop the ARRIVE guidelines, which included researchers and statisticians from multiple fields, and journal editors from Nature Cell Biology, Science, Laboratory Animals, and the British Journal of Pharmacology. This initial revision of the guidelines was a checklist of 20 items intended to cover the "minimum information that all scientific publications reporting research using animals should include," such as specific details about the animals used, their living conditions, and the experimental, statistical, and analytical methods used in the study. The guidelines were written using the CONSORT statement, a general-purpose 25-item checklist of recommendations for reporting randomized trials, as a basis.
Initial adoption
By 2016, over 600 journals had endorsed the guidelines, with over 150 endorsing the guidelines in 2015 alone; by 2020, that number risen to over a thousand. Despite this, multiple studies between 2014 and 2018 found that the guidelines had been largely ignored by researchers and had made little impact in the general quality of reporting of papers published after the guidelines were issued. Surveys conducted in China in 2017 and 2019 found that only 9.4% and 13.1% of journals were aware of the guidelines, and none specifically directed their authors to follow the guidelines. This low level of adoption by reviewers and researchers was partially attributed to the amount of effort required from journals and editors to check and enforce the guidelines; the original list's 20 items were made up of multiple sub-items, resulting in effectively 38 items to follow. The lack of adoption was also attributed to a lack of awareness from researchers of the significance of incomplete reporting.
Revision
In 2020, in response to low levels of adoption & enforcement of the guidelines, an international working group, supported by NC3Rs, published ARRIVE 2.0, a revision of the ARRIVE guidelines. The revision was intended to clarify the guidelines for researchers, to prioritize the most important items to make enforcement by journal editors and reviewers more manageable, and to provide context & reasoning for the importance of each guideline. The most significant change from the original ARRIVE guidelines was the splitting of the checklist into two separate checklistsan "Essential 10", which encompasses the "basic minimum" that must be included in a manuscript for its findings to be assessed reliably, and a "Recommended Set", which encompasses items that add context and helpful details to a manuscript.
Meta-analyses of studies in the fields of peritoneal dialysis and orthodontics have found that adoption and enforcement of the revised guidelines continues to be sub-optimal.
References
External links
Animal testing
Bioethics
Design of experiments
Reporting guidelines | ARRIVE guidelines | [
"Chemistry",
"Technology"
] | 845 | [
"Bioethics",
"Animal testing",
"Ethics of science and technology"
] |
67,124,208 | https://en.wikipedia.org/wiki/ESO%20593-8 | ESO 593-8, which is known simply as 'The Bird' (also ESO 593-IG 008 or IRAS 19115–212) is group of interacting galaxies located in the constellation of Sagittarius, 650 million light-years away from Earth. It was created by a merger of two spiral galaxies and an irregular dwarf-galaxy. The resulting galaxy has a size similar to the Milky Way: around 100,000 light years. The galaxies were imaged by the Hubble Space Telescope and released in April 2008. The European Southern Observatory has also used the Very Large Telescope to resolve fine details of the galaxy with the use of adaptive optics.
References
Sagittarius (constellation)
Spiral galaxies
Interacting galaxies | ESO 593-8 | [
"Astronomy"
] | 151 | [
"Sagittarius (constellation)",
"Constellations"
] |
67,126,169 | https://en.wikipedia.org/wiki/Bisantrene | Bisantrene is an anthracenyl bishydrazone with anthracycline-like antineoplastic activity and an antimetabolite. Bisantrene intercalates with and disrupts the configuration of DNA, resulting in DNA single-strand breaks, DNA-protein crosslinking, and inhibition of DNA replication. This agent is similar to doxorubicin in chemotherapeutic activity, but unlike anthracyclines like doxorubicin, it exhibits little cardiotoxicity.
In addition to its anthracycline-like activity, a July 2020 seminal article by Su, R et al. at the City of Hope Hospital in Los Angeles, California, USA first identified bisantrene to also be a potent (IC50 = 142nM) inhibitor of the Fat Mass and Obesity (FTO) associated protein, which is a m6A RNA demethylase. The same study found that bisantrene is a weak inhibitor of ALKBH5, which is the only other demethylase, i.e. bisantrene is also a selective inhibitor of FTO.
In 2021, bisantrene was demonstrated preclinically to be cardioprotective when administered together with cardiotoxic anthracyclines.
A bisantrene combination treatment is currently (as at early 2024) nearing the end of a Phase II clinical trial to assess its efficacy in treating AML in heavily pretreated patients and to assess any adverse side effects, including any cardiotoxicity of the combination. The December 2023 interim findings are given in the History section.
Medical uses
Clinical trials of Bisantrene in the 1980s showed efficacy in a range of leukaemias (including Acute Myeloid Leukaemia), breast cancer, and ovarian cancer.
Adverse Side Effects
High doses of bisantrene (above 200 mg/m2/day) cause adverse side effects typical of anthracycline chemotherapeutics. Common adverse side effects include hair loss, bone marrow suppression, vomiting, rash, and inflammation of the mouth. For a chemotherapy drug, it is considered to have relatively low toxicity.
Unlike other anthracycline chemotherapeutics, Bisantrene shows low levels of cardiotoxicity. In a Phase III metastatic breast cancer clinical, patients were exposed to cumulative doses in excess of 5440 mg/m2 without developing cardiac damage. The same study observed significantly lower rates of hair loss and nausea compared to patients given doxorubicin.
Three Mechanisms of Action
Bisantrene has three distinct mechanisms of action.
Bisantrene contains an appropriately sized planar electron-rich chromophore to be a DNA intercalating agent, and in vitro, it is a potent inhibitor of DNA and RNA synthesis.
Bisantrene is also a potent and selective inhibitor of the FTO enzyme, which is an m6A mRNA demethylase. Bisantrene acts by occupying FTO's catalytic pocket. This is a relatively recent discovery (July 2020).
Finally, the University of Newcastle and the Hunter Medical Research Institute found in late 2021 preclinical research that bisantrene has a cardioprotective mechanism of action when administered together with a cardiotoxic drug such as doxorubicin. As at early 2024, the molecular basis for this cardioprotective effect hasn't been announced by the researchers.
Bisantrene's cardioprotective mechanism of action is important because "15 of the 35 commercially available anti-cancer drugs have direct cardiotoxic effects on HCM (human cardiomyocytes)."
According to the Australian Cardiovascular Alliance Cardio-Oncology Working Group , a drug which is simultaneously anticancer and cardioprotective is the "Holy Grail" of Cardio-Oncology.
History
Bisantrene was developed by Lederle Laboratories during the 1970s, a subsidiary of American Cyanamid, as a less cardiotoxic alternative to anthracyclines. Across the 1980s and early 1990s, over 40 clinical trials were conducted using Bisantrene. The National Cancer Institute (NCI)] undertook a large scale trial using Bisantrene under the name "Orange Crush", including a range of preclinical trials which found bisantrene to be inactive when taken orally, though was found to be efficacy towards some cancer cells intravenous, intraperitoneal, or subcutaneous.
In the 1980s, forty-four patients with metastatic breast cancer who had undergone extensive combination chemotherapy with doxorubicin and had failed to respond to the combination, were treated with bisantrene. From 40 patients that were evaluated, 9 showed a partial response, and 18 showed the cancer was not progressive but stabilised.
Bisantrene was approved for human medical use in France in 1990 to target Acute Myeloid Leukemia (AML) cancers.
It has undergone 46 Phase II trials with 1,800 patients to test its efficacy against fighting cancer cells.
The drug was delisted in the early 1990s due to a series of pharmaceutical mergers and acquisitions.
In November 2019, researchers at the City of Hope Hospital in Los Angeles, California published that a drug with codename "CS1" is a potent and specific inihibitor of FTO, a m6A mRNA demethylase. This article didn't identify that "CS1" is actually bisantrene.
In 2020 at Sheba Hospital, Tel Aviv, Israel, four out of 10 heavily pretreated AML patients responded to bisantrene administered as a single agent. All four of these responding patients had extramedullary disease.
In July 2020, researchers at the City of Hope Hospital in Los Angeles, California published that bisantrene (for which they mostly used the codename "CS1") is a potent and specific inihibitor of FTO, a m6A mRNA demethylase. The fact that "CS1" is actually bisantrene is mentioned near the start of the Discussion section of the article.
In 2021, researchers at the University of Chicago used bisantrene (which they referred to as "CS1", using the codename adopted by the City of Hope Hospital) to successfully inhibit FTO in a preclinical experiment.
In a preclinical trial published in January 2022, researchers at the University of Lille used bisantrene to inhibit FTO in order to test whether an FTO inhibitor could potentially be used to treat disregulation of glucose metabolism in Type 2 diabetes.
In 2022 researchers at the University of Texas tested a bisantrene, venetoclax and decitabine combination for AML preclinically.
Based on the 2020 clinical study at Sheba Hospital and the two University of Texas pre-clinicals cited above, the most recent clinical trial is the one currently (as at early 2024) underway as a combination treatment for AML in heavily pretreated patients at Sheba Hospital, Tel Aviv, Israel. In the dose-finding stage, three out of six of the heavily pretreated patients were bridged to a bone marrow transplant. Interim results of the expansion stage were announced in December 2023 in a poster presented at the 2023 American Society of Haematologists conference. The results are promising for such heavily pre-treated patients. Six patients recovered sufficiently to be bridged to a bone marrow transplant. No cardiotoxity of the Bisantrene, Fludarabine and Clofarabin combination was observed.
In November 2023, researchers at the University of Newcastle and at Race Oncology Limited jointly published a preclinical study in the peer-reviewed journal Blood. It found that bisanantrene is synergistic with the hypomethalating agent decitabine for treatment of AML. The researchers recommended that this combination should proceed to the clinic.
Alternate Names for Bisantrene
Names
Bisantrene's chemical name is 9, 10-antrhracenedicarboxaldehydebis [(4, 5-dihydro-1H-imidazole-2-yl) hydrazine] dihydrochloride.
Bisantrene was given the nickname “Orange Crush” in the 1980s due to its fluorescent orange color when in solution.
Bisantrene is also sometimes referred to as "CS1" in cancer research journals, starting with the July 2020 seminal article by Su, R et al. The fact that "CS1" is actually bisantrene is mentioned near the start of the Discussion section of that article.
References
Anthracenes
Hydrazones
Imidazoles | Bisantrene | [
"Chemistry"
] | 1,844 | [
"Hydrazones",
"Functional groups"
] |
67,127,097 | https://en.wikipedia.org/wiki/%CE%94-3-Tetrahydrocannabinol | Δ-3-Tetrahydrocannabinol (often abbreviated as delta-3-THC or Δ3-THC) is a synthetic isomer of tetrahydrocannabinol (THC) developed during the original research in the 1940s to develop synthetic routes to the natural products Δ8-THC and Δ9-THC found in the cannabis. While the normal trans configuration of THC is in this case flattened by the double bond, it still has two enantiomers as the 9-methyl group can exist in an (R) or (S) conformation. The (S) enantiomer has similar effects to Δ9-THC though with several times lower potency, while the (R) enantiomer is many times less active or inactive, depending on the assay used. It has been identified as a component of vaping liquid products.
See also
7,8-Dihydrocannabinol
Cannabitriol
Delta-4-Tetrahydrocannabinol
Delta-7-Tetrahydrocannabinol
Delta-10-Tetrahydrocannabinol
Hexahydrocannabinol
JWH-138
Parahexyl
References
Benzochromenes
Cannabinoids
Heterocyclic compounds with 3 rings | Δ-3-Tetrahydrocannabinol | [
"Chemistry"
] | 278 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
67,127,278 | https://en.wikipedia.org/wiki/%CE%94-7-Tetrahydrocannabinol | Δ-7-Tetrahydrocannabinol (Delta-5-THC, Δ5-THC; alternatively numbered as Δ-5-Tetrahydrocannabinol, Δ7-THC) is a synthetic isomer of tetrahydrocannabinol. The (6aR,9S,10aR)-Δ7-THC epimer is only slightly less potent than Δ9-THC itself, while the (9R) epimer is much less potent.
See also
7,8-Dihydrocannabinol
Delta-3-Tetrahydrocannabinol
Delta-4-Tetrahydrocannabinol
Delta-8-Tetrahydrocannabinol
Delta-10-Tetrahydrocannabinol
Hexahydrocannabinol
References
Benzochromenes
Cannabinoids | Δ-7-Tetrahydrocannabinol | [
"Chemistry"
] | 190 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
67,128,633 | https://en.wikipedia.org/wiki/Rebeca%20Uribe%20Bone | Rebeca Uribe Bone (7 July 1917 – 8 May 2017) was the first woman to graduate in engineering in Colombia. She was a chemical engineer and the first woman to graduate in Chemical Engineering from the Pontifical-Bolivarian University of Medellin.
Early life
Rebeca Uribe Bone was born in Guatemala City on 7 July 1917, the daughter of Guillermo Uribe Echevarría, a Spanish accounting expert of Basque descent, and María Teresa Bone Romero, a Guatemalan of English descent.
Guillermo Uribe, Rebecca's father, left the Basque Country and moved to Guatemala City, where he met and married Maria Teresa Bone. After having six children, they left Guatemala in 1928 and moved to Colombia, where they settled in Medellin and had two further children. The couple were liberal freethinkers and encouraged their daughters to study and take up professions. Ultimately two daughters became engineers: Rebeca a chemical engineer; Guillermina Uribe Bone, a civil engineer; Helena became a doctor, a fourth sister Maria Teresa began to study architecture before an early marriage. The fifth daughter, Carmen, suffered from meningitis as a child which prevented her from studying for a career, but she finished high school. Their brothers became a pilot, lawyer and an architect.
Education
Rebeca completed high school at the Central Women's Institute in Medellin. At the time, the university was opening its doors to suitably qualified women, and her teachers had been very good mathematicians and chemists. These influenced Rebekah to choose chemical engineering as a university career. Her parents were very receptive to the idea, and encouraged her to go to college, as her brothers did. Her sister Guillermina said in 2004, “Mi papá estaba adelantado para la época, por eso nos estimuló muchísimo. Él tenía un pensamiento sobre la mujer más amplio”. "My father was ahead of his time, which is why he encouraged us so much. He had wider expectations about women."
Rebeca Uribe Bone was taught by Joaquín Vallejo Arbeláez, Colombian civil engineer, businessman and writer who later served as 12th Permanent Representative of Colombia to the United Nations. She took courses in general culture and teacher training. Many of her classmates later took up teaching.
On 19 October 1945, Rebeca Uribe Bone received her degree from the Pontifical Bolivarian University (then the Bolivarian Catholic University), and qualified as an industrial chemical engineer
As a new graduate, she began working in the Bavaria brewing company's quality department, and before completing her first year as a chemical engineer, she met the son of a friend of her father's. He was Basque and was visiting Bogota for a season.
Personal life
Rebeca married him and they set up home in Calin, set up a factory, and had a son. They moved to Bilbao in Spain in the 1980s.
Rebeca was active into old age and used to walk the streets of the neighborhood every day on her own. She was knocked down in a bicycle accident at the age of 95, and on 8 May 2017, at the age of almost a hundred, she died in Bilbao.
Legacies
Premio Rebeca Uribe Bone, Historial Premio Rebeca Uribe Bone a la Mejor Opción de Grado en Ingeniería Química elaborada por una mujer o grupo de mujeres. Consejo Profesional de Ingeniería Química de Colombia - CPIQ (The Rebeca Uribe Bone Award for the Best Degree Option in Chemical Engineering prepared by a woman or group of women).
References
Colombian chemical engineers
Colombian women engineers
20th-century women engineers
People from Guatemala City
2017 deaths
1917 births
20th-century Colombian women scientists
Women chemical engineers | Rebeca Uribe Bone | [
"Chemistry"
] | 787 | [
"Women chemical engineers",
"Chemical engineers"
] |
67,129,260 | https://en.wikipedia.org/wiki/Anson%20equation | In electrochemistry, the Anson equation defines the charge-time dependence for linear diffusion control in chronocoulometry.
The Anson equation is written as:
where,
Q = charge in coulombs
n = number of electrons (to reduce/oxidize one molecule of analyte)
F = Faraday constant, 96485 C/mol
A = area of the (planar) electrode in cm2
C = concentration in mol/cm3;
D = diffusion coefficient in cm2/s
t = time in s.
This is related to the Cottrell equation via integration with respect to time (t), and similarly implies that the electrode is planar.
See also
Voltammetry
Electroanalytical methods
Limiting current
Cottrell equation
References
Electrochemical equations | Anson equation | [
"Chemistry",
"Mathematics"
] | 161 | [
"Mathematical objects",
"Equations",
"Electrochemistry",
"Electrochemistry stubs",
"Physical chemistry stubs",
"Electrochemical equations"
] |
67,129,473 | https://en.wikipedia.org/wiki/Space%20sustainability | Space sustainability aims to maintain the safety and health of the space environment, as well as planetary environments.
Similar to sustainability initiatives on Earth, space sustainability seeks to use the environment of space to meet the current needs of society without compromising the needs of future generations. It usually focuses on space closest to Earth, Low Earth Orbit (LEO), since this environment is the one most used and therefore most relevant to humans. It also considers Geostationary Equatorial Orbit (GEO) as this orbit is another popular choice for Earth-orbiting mission designs.
The issue of space sustainability is a new phenomenon that is gaining more attention in recent years as the launching of satellites and other space objects has increased. These launches have resulted in more space debris orbiting Earth, hindering the ability of nations to operate in the space environment while increasing the risk of a future launch-related accident that could disrupt its proper use. Space weather also acts as an outstanding factor for spacecraft failure. The current protocol for spacecraft disposal at end-of-life has, at large, not been followed in mission designs and demands extraneous amounts of time for disposal.
Precedent created through prior policy initiatives has facilitated initial mitigation of space pollution and created a foundation for space sustainability efforts. To further mitigation, international and transdisciplinary consortia have stepped forward to analyze existing operations, develop standards, and incentivize future procedures to prioritize a sustainable approach. A shift towards sustainable interactions with the space environment is growing in urgency due to the implications of climate change and increasing risk to spacecraft as time presses on.
Fundamentals
Space sustainability requires all space participants to have three consensuses. The space field should be used peacefully, jointly protect the space field from harm, and maximize space utilization through environmental, economic, and security exploration of space. These consensuses also clarify the relationship between space sustainability and international security, that states and individuals explore space for various purposes. Their reliance on space needs to be guided by rules, order, and policies and obtain more benefits without negatively affecting the space environment and space activities.
However, striking an agreement remains challenging even with such demands in place. In the discussions between countries on long-term sustainability, technical improvements are given more importance than introducing and applying new legal regimes. Specifically, technical approaches to space debris have been proposed, such as debris removal. Specific data on space debris is also being explored to help study its impact on sustainability and promote further cooperation between countries.
Current state
Space sustainability comes into play to address the pressing current state of near-Earth orbits and its high amounts of orbital debris. Spacecraft collisions with orbital debris, space weather, overcrowding in low Earth orbit (LEO) makes spacecraft susceptible to higher rates of failure. The current end-of-life protocol for spacecraft exacerbates the space sustainability crisis; many spacecraft are not properly disposed, which increasing the likelihood of further collisions.
Orbital debris
Orbital debris is defined as unmanned, inoperate objects that exist in space. This orbital debris breaks down further as time progresses as a result of naturally occurring events, such as high-velocity collisions with micrometeoroids, and forced events, such as a controlled release of a launch vehicle. In LEO, these collisions can take place at speeds anywhere between an average velocity of 9 kilometers per second (km/s) and 14 km/s relative to the debris and spacecraft. In GEO, however, these high-speed collisions are a much lower risk as the average relative velocity between the debris and spacecraft is typically between 0 km/s and 2.5 km/s. As of 2012, the United States Joint Space Operations Center tracked 21,000 pieces of orbital debris larger than 10 cm in Earth's nearby orbits (LEO, GEO, and Sun-synchronous), where 16,000 of these pieces are catalogued. Space debris can be categorized into three categories: small, medium, and large. Small debris is for pieces that are less than 10 centimeters (cm). Medium-sized debris is for pieces larger than 10 cm, but not an entire spacecraft. Large-sized debris has no official classification, but typically refers to entire spacecraft, such as an out of use satellite or launch vehicle. It is difficult to track small-sized debris in LEO, and challenging to track small and medium-sized debris in GEO. Yet this statement is not to discount the abilities of LEO and GEO tracking capabilities, the smallest piece of tracked debris can weigh as low as ten grams. If the size of the debris prohibits it from being tracked, it also cannot be avoided by the spacecraft and does not allow the spacecraft to lower its risk of collisions. The likelihood of the Kessler syndrome, which essentially states that each collision produces more debris, grows larger as the amount of orbital debris multiplies, increasing the amount of further collisions until space cannot be used entirely.
Space weather
Space weather poses a risk to satellite health, consequently, resulting in greater amounts of orbital debris. Space weather impacts satellite health in a variety of ways. Firstly, surface charging from the Sun's surface facilitates electrical discharges, damaging on-orbit electronics, posing a threat to mission failure. Single Event Upsets (SEUs) can also damage electronics. Dielectric charging and bulk charging can also occur, causing energy problems within the spacecraft. Additionally, at altitudes less than one thousand kilometers, atmospheric drag can increase during solar storms by increasing the altitude of the spacecraft, only adding more drag onto the spacecraft. These factors degrade performance over the spacecraft's lifetime, leaving the spacecraft more susceptible to further system and mission failures.
Overcrowding
There has been a dramatic increase in the use of LEO and GEO orbits over the last sixty years since the first satellite launch in 1957. To date, there have been approximately ten thousand satellite launches, whereas only approximately 2000 are still active. These satellites can be used for a variety of purposes, which are telecommunications, navigation, weather monitoring, and exploration. Within the coming decade, companies like SpaceX are predicted to launch an additional fifteen thousand satellites into LEO and GEO orbits. Microsatellites built by universities or research organizations have also increased in popularity, contributing to the overcrowding of near earth orbits. This overcrowding of LEO and GEO orbits increases the likelihood of potential collisions among satellites and orbital debris, contributing further to the large amount of orbital debris present in space.
End of life protocol
The current end of life protocol is that at the end of mission, spacecraft are either added to the graveyard orbit or at a low enough altitude that drag will allow the spacecraft to burn up upon reentry and fall back to Earth. Approximately twenty satellites are put into the graveyard orbit each year. There is no current process to return satellites to Earth after entering the graveyard orbit. The process of a spacecraft returning to Earth via drag can take between ten and one hundred years. This protocol is critical to reduce overcrowding in near-Earth orbits.
Mega constellation and space debris
The impact of constellations on the space environment has also been studied, such as the probability of collisions of mega constellations in the presence of large amounts of space debris. Although studies have shown that the predictors of mega constellations are highly variable, specific information related to mega constellations is not transparent.
But any catastrophic collision, as in the case of Kessler syndrome, has consequences for people and the environment. Putting this thinking into mega constellations, mega constellations existence may have potential benefits, but it will not bring adequate help to the governance of space debris. At the same time, the space debris situation cannot be underestimated or ignored because of the existence of mega constellations.
Areas
Planetary environment
Space environment
The existence of orbital debris has caused great trouble to the conduct of space activities. The development of space sustainability has not given sufficient political attention, although some warnings and discussions have made this abundantly clear. Debris management is still voluntary on the part of the state, and there are no laws mandating debris management practices, including the amount of debris to be managed. Although the UN Space Debris Mitigation Guidelines were promulgated in 2007 as an initial measure of space debris governance, there is still no broad consensus or action on further limits on space debris after that.
The difficulties for individuals wishing to participate in debris management initiatives cannot be ignored. Any individual or sector desiring to participate in space debris operations needs to obtain permission from the launching state, which is difficult for the launching state to do. This is because the process of space debris management inevitably has a negative impact on other space objects, and there is a lot of subsequent liability in terms of financial consumption. Therefore, the launching state would argue that space debris management requires the joint efforts of all states. However, it is difficult to determine what actions can be taken to gain acceptance between countries.
Regulations
Current space sustainability efforts rely heavily on the precedent set by regulatory agreements and conventions of the twentieth century. Much of this precedent is included in or is related to the Outer Space Treaty of 1963, which represented one of the initial major efforts by the United Nations to create legal frameworks for the operation of nations in space.
Pre-Outer Space Treaty
The international community has had concerns about space contamination since the 1950s prior to the launch of Sputnik I. These concerns stemmed from the idea that increasing rates of exploration into further areas of outer space could lead to contamination capable of damaging other planetary bodies, resulting in limitations to human exploration on these bodies and potential harm to the Earth. Efforts to combat these concerns began in 1956 with the International Astronautical Federation (IAF) and the United Nations Committee on the Peaceful Uses of Outer Space (COPUOUS). These efforts continued to 1957 through the National Academy of Sciences and International Council for Science (ICSU). Each of these organizations aimed to study space contamination and develop strategies for how to best address its potential consequences. The ICSU went on to create the Committee on Contamination by Extraterrestrial Exploration (CETEX) that put forward recommendations leading to the establishment of the Committee on Space Research (COSPAR). COSPAR continues to address outer space research on an international scale today [cite cospar].
Outer Space Treaty
Relevant regulations of international space law to sustainability in space can be found in the Outer Space Treaty, which was adopted by the UN General Assembly in 1963. The Outer Space Treaty contains seventeen articles designed to create a basic framework for how international law can be applied in outer space. Basic principles of the Outer Space Treaty include the provision in Article IX that parties should "avoid harmful contamination of space and celestial bodies;" definitions of "harmful contamination" are not provided. Other articles of relevance to space sustainability include articles I, II, and III that concern the fair and inclusive international use of space in a manner free from sovereignty, ownership, or occupation by any nation. In addition, articles VII and VIII protect ownership by their respective countries of any objects launched to space while attributing responsibility for any damages to the property or personnel of other countries by those objects to said countries. Descriptions or definitions for what these damages may entail are not provided.
COSPAR Planetary Protection Policy
Principles of Article IX provided the basis for the Committee of Space Research (COSPAR) Planetary Protection Policy guidelines, which are generally well-regarded among scientific experts. Such guidelines, however, are non-binding and often described as "soft-law," as they lack legal mandate. The Planetary Protection Policy is primarily concerned with providing information regarding best practices to avoid contamination of the space environment during space exploration missions. COSPAR believes that the prevention of such contamination is in the best interest of humanity as it may impede scientific progress, exploration, and the mission of a search for life. In addition, the argument is made that cross-contamination of the Earth can be potentially harmful to its environment due to the largely unknown nature of potential space contaminants.
Other relevant regulations
Regulatory clarifications concerning the Outer Space Treaty of 1963 of relevance to space sustainability were made in subsequent years. The 1967 Return Agreement relates mainly to the return of lost astronauts to their appropriate nations, but also requires Outer Space Treaty signing nations to assist other nations with the return of objects that return to Earth from orbit to their proper owners The 1972 Liability Convention attributes liability for damages from space objects to the nation that launched the object, regardless of whether that damage occurred in space or on Earth. Other clarifications include the 1975 registration convention that attempted to create mechanisms for nations to identify space objects, and the 1979 Moon Agreement that established protections for the environments of the Moon and other nearby planetary bodies. These agreements and conventions represented attempts to improve the initial Outer Space Treaty as space exploration continued to grow in importance throughout the 20th century.
Attitudes
Countries and major international institutions
Both the state and space agencies are working to improve the laws and regulations that facilitate the long-term sustainability of space. For example, the European Code of Conduct for Space Debris Mitigation signed by France, the UK and other countries in 2016. China, Brazil, Mexico and others have legal background and methodological measures under long-term space sustainability. However, the main problem is that until the concept of space sustainability is agreed between countries, inter-regional efforts are not working well.
Currently, the Committee on the Peaceful Uses of Outer Space (COPUOS) encourages states to incorporate the space debris mitigation guidelines developed by bodies such as the Inter-Agency Space Debris Coordination (IADC) into their national legislation, thereby regulating state behavior. Some countries have responded positively to this, such as Switzerland, the Netherlands and Spain. However, there are still some countries that do not consider debris management approaches in their national legislation, such as Japan and Australia. Many delegates at the COPUOS meeting expressed their reasons for doing so, arguing that space debris management is closely linked to technology and funding. Technology is dynamic and constantly evolving. Therefore, the incorporation of debris governance guidelines into national law is not an immediate priority at this time.
Scientific attitudes
A study outlined rationale for governance that regulates the current free externalization of true costs and risks, treating orbital space around the Earth as an "additional ecosystem" or a common "part of the human environment" which should be subject to the same concerns and regulations like oceans on Earth. While scientists may not have the means to make and enforce global laws themselves, the study concluded in 2022 that it needs "new policies, rules and regulations at national and international level".
Mitigation
Sustainability mitigation efforts include but are not limited to design specifications, policy change, removal of space debris, and restoration of orbiting semi-functional technologies. Efforts begin by regulating the debris released during normal operations and post-mission breakups [6]. Due to the increased awareness of high-velocity collisions and orbital debris in the previous decades, missions have adapted design specifications to account for these risks. For example, the RADARSAT program implemented 17 kilograms of shielding to their spacecraft, which increased the program's predicted success rate to 87% from 50%. Another effort in mitigation is restoring semi-functional satellites, which allows a spacecraft classified as "debris" to "functional." Space debris mitigation focuses on limiting debris release during normal operations, collisions and intentional destruction. Mitigation also includes reducing the possibility for post-mission breakups due to stored energy and/or operations phases, as well as addressing procedure for end of mission disposal for spacecraft.
Space Sustainability Rating
One example leading the regulatory sustainability measures is the Space Sustainability Rating (SSR), which is an instigator for industry competitors to incorporate sustainability into spacecraft design. The Space Sustainability Rating was first conceptualized at the World Economic Forum Global Future Council on Space Technologies designed by international and transdisciplinary consortia. The four leading organizations are the European Space Agency, Massachusetts Institute of Technology, University of Texas at Austin, and BryceTech with the goal to define the technical and programmatic aspects of the SSR. The SSR represents an innovative approach to combating orbital debris through incentivizing the industry to prioritize sustainable and responsible operations. This response entails the consideration of potential harm to the space environment and other spacecraft, all while maintaining mission objectives and high-quality service. The rating takes inspiration from other standards, like leadership in energy and environmental design (LEED) for the building sector. Several of the factors emphasized in the rating were extracted from LEED design considerations like the incorporation of feedback and public comments, or the rating's advocacy to influence policy, such as orbit fragmentation risks, collision avoidance capabilities, trackability, and adoption of international standards.
Tracking
Tracking is one of the main Space Sustainability Rating modules' efforts. The module "Detectability, Identification and Tracking" (DIT) consists of standardizing the comparison of satellite missions to encourage satellite operators to improve their satellite design and operational approaches for the observer to detect, identify, and track the satellites. Tracking presents challenges when the observer seeks to monitor and predict the spacecraft behavior over time. While the observer may know the name, owner, and instantaneous location of the satellite, the operator controls the full knowledge of the orbital parameters. The Space Situational Awareness (SSA) is one the tools geared towards solving the challenges presented when tracking orbiting satellites and debris. The SSA continuously tracks objects using ground-based radar and optical stations so the orbital paths of debris can be predicted and operations avoid collisions. It feeds data to 30 different systems like satellites, optical telescopes, radar systems, and supercomputers to predict risk of collision days in advance. Other efforts in tracking orbital debris are made by the US Space Surveillance Network (SSN).
Removal
Under the "External Services" module of the SSR, the rating offers commitment to use or demonstration of use of end-of-life removal services. Space debris mitigation measures are found to be inadequate to stabilize debris environments with an actual current compliance of approximately sixty percent. Moreover, a low compliance rate of approximately thirty percent of the 103 spacecraft that reached end of life between 1997 and 2003 were disposed of in a graveyard orbit. Since policy has not caught up to ensure the longevity of LEO for future generations, actions like Active Debris Removal (ADR) are being considered to stabilize the future of LEO environment. Most famous removal concepts are based on directed energy, momentum exchange or electrodynamics, aerodynamic drag augmentation, solar sails, auxiliary propulsion units, retarding surfaces and on-orbit capture. As ADR consists of an external disposal method to remove obsolete satellites or spacecraft fragments. Since large-sized debris objects in orbit provide a potential source for tens of thousands of fragments in the future, ADR efforts focus on objects with high mass and large cross-sectional areas, in densely populated regions, and at high altitudes; in this instance, retired satellites and rocket bodies are a priority. Other practical advancements toward space debris removal include missions like RemoveDEBRIS and End-of-Life Service (ELS-d).
Growing urgency
The previous reduced state of regulation and mitigation on space debris and rocket fuel emissions is aggravating the Earth's stratosphere through collisions and ozone depletion, increasing the risk for spacecraft health through its lifetime.
Inaccessibility to LEO
Due to the increase of satellites being launched and the growing amount of orbital debris in LEO, the risk of LEO becoming inaccessible over time (in accordance with the Kessler syndrome) is increasing in likelihood. The mitigation policies for creating space debris fall under an area of voluntary codes by the states, although it has been disputed whether the Article I Outer Space Treaty or the Article IX Outer Space Treaty protects the space environment from deliberate harm, which has yet to be upheld. In 2007, an inactive Chinese satellite was purposefully destroyed by the Chinese government as a part of their anti-satellite weapon test (ASAT), spreading nearly 2800 objects of space debris five centimeters or larger into LEO. An analysis concluded that about eighty percent of the debris will remain in LEO nine years after this destruction. In addition, the destruction increased the collision likelihood for three Italian satellites that launched the same year as the Fengyun-1C destruction. The increase in collision ranged between ten and sixty percent. However, there were no legal consequences against the Chinese government.
Rocket fuel emissions
When rockets are launched into space, parts of their fuel enter the stratosphere of the Earth. Rocket fuel emissions are made up of carbon dioxide, water, hydrochloric acid, alumina and soot particles. The most concerning emissions from rocket fuel are chlorine and alumina particles from solid rocket motors (SRMs) and soot from kerosene fueled engines. When the hydrochloric acid from the engine exhaust dissociates, the free chlorine roams freely in the stratosphere. The chemical reaction between these chlorine and alumina causes ozone depletion. In addition, the soot particles form over a black umbrella over the stratosphere which can cause the temperature of the Earth's surface to lower and further depleting the ozone layer, an unintentional form of geoengineering. The nature of geoengineering has been disputed as a form of mitigating global warming and has the possibility of being banned and holding rockets accountable for the soot particles they distribute to the stratosphere. New types of engines and fuels are emerging, mainly the liquid oxygen (LOX) and monomethylhydrazine engine, but there is minimal research on their impact on the environment besides their emission of hydroxide and nitrogen oxide compounds, two molecules that have significant impact on the ozone layer. Currently, rocket fuel emissions have been deemed insignificant when it comes to their consequences to Earth's environment and LEO. However, emissions will increase in the coming years, making rocket fuel's contribution to global warming much more significant.
Beyond LEO
Space sustainability concepts and mindsets tend to stay in Low Earth Orbit (LEO). One reason that cannot be ignored is that it is easier to discuss the problem at hand than to speculate on the unknown. There are also examples to prove that since Apollo 17 completed its mission and stayed in Low Earth orbit in 1972, human-crewed space missions in Low Earth orbit have ceased to exist. In this way, it is a reasonable assumption that the closer Moon could be the next object to be explored when the gaze is not limited to LEO. Both lunar orbit and LEO are part of the space environment. In the context of the presence of space debris in LEO, it is normal to speculate that lunar orbit also possesses the nuisance of debris. Space debris measures similar to those in LEO related to space sustainability would be taken.
Not only has the Moon been the subject of study, but other bodies have also been taken into account. Elon Musk, the chief executive of SpaceX at the International Astronautical Congress in 2016, explained the ambitious goal of exploring Mars in the 22nd century. But complicated issues remain, such as the technical aspects of achieving long-distance space flight and the rules and legal aspects associated with the technology, all of which need to be considered.
See also
Asteroid mining#Regulation and safety
Common heritage of humanity
Graveyard orbit
Human presence in space
Kessler syndrome
List of space debris producing events
Rights of nature
Satellite collision
Spacecraft cemetery
Space debris
Space law
References
Space debris
Global issues
Space hazards
Near-Earth objects
Future problems
Pollution | Space sustainability | [
"Technology"
] | 4,741 | [
"Space debris"
] |
67,129,616 | https://en.wikipedia.org/wiki/Lichtheimiaceae | Lichtheimiaceae is a family of fungi in the order Mucorales. The family was circumscribed in 2013 after a molecular phylogenetic analysis helped delineate a new family structure for the Mucorales.
Genera
Circinella – 11 spp.
Dichotomocladium – 5 spp.
Fennellomyces – 4 spp.
Lichtheimia – 7 spp.
Phascolomyces – 1 sp.
Rhizomucor – 6 spp.
Thamnostylum – 4 spp.
Thermomucor – 1 sp.
Zychaea – 1 sp.
References
Zygomycota
Fungus families
Taxa described in 2009 | Lichtheimiaceae | [
"Biology"
] | 139 | [
"Fungus stubs",
"Fungi"
] |
67,130,162 | https://en.wikipedia.org/wiki/Shadow%20rate | The shadow rate is an interest rate in some financial models. It is used to measure the economy when nominal interest rates come close to the zero lower bound. It was created by Fischer Black in his final paper, "Interest Rates as Options".
The shadow rate derives from Fischer Black's insight that currency is an option. If someone has money, the person can either (1) spend it today or (2) not spend it and have money tomorrow. Thus, when loans would return less money than was initially loaned out, investors will choose to "exercise the option" and not loan their money. Thus, the nominal short-term interest rate is always greater than or equal to zero. In Black's model, the shadow nominal short-term rate is what the nominal short-term rate would be if it was allowed to go below the zero lower bound.
When the shadow nominal short-term rate is positive, the nominal short-term rate is equal to the shadow rate. But when the shadow short-term rate is negative — such as during deflation or a bad recession with low inflation — the nominal short-term rate will diverge and stay above zero. In Black's model, even when nominal short-term interest rates stay close to zero, the long-term nominal interest rates can be well above zero. This is because nominal interest rates behave like options and there is some chance that the shadow short-term rate becomes positive in the future.
There is also a shadow real rate. The shadow real short-term rate is equal to the shadow nominal short-term rate minus expected inflation.
Fischer Black published his paper in 1995 and mentioned that the most recent time that the USA had experienced the zero lower bound was the Great Depression. Shadow rate models got renewed interest with the Financial Crisis of 2007–2008 when interest rates plunged to near zero and, even, below zero in some instances.
In contemporary macroeconomic terms, the concept, shadow irate, refers to an expansionary monetary environment during a period of zero ZLB. In such a period, when the central banks implement additional expansionary measures such as quantitative easing (QE), the monetary environment is actually more expansionary than implied by the nominal interest rate alone, and it is possible to calculate what nominal interest rate corresponds to the monetary environment. This interest is known as shadow interest.
Models
Due to the option effect, the shadow short-term rate cannot be observed directly in the market. Economists use models to infer its value from its effect on longer-term interest rates in the yield curve. The value of the shadow short-term rate depends on assumptions about how interest rates move, so different models might calculate different values for it.
Jing Cynthia Wu and Fan Dora Xia's models were published in "Measuring the Macroeconomic Impact of Monetary Policy at the Zero Lower Bound" and in "Negative Interest Rate Policy and Yield Curve". Their rates are also available at the Federal Reserve Bank of Atlanta.
Leo Krippner's model was published in the book Zero Lower Bound Term Structure Modeling: A Practitioner’s Guide. His initial models were done while at the Reserve Bank of New Zealand.
References
Mathematical finance
Monetary policy | Shadow rate | [
"Mathematics"
] | 647 | [
"Applied mathematics",
"Mathematical finance"
] |
67,130,324 | https://en.wikipedia.org/wiki/Extreme-ultraviolet%20Stellar%20Characterization%20for%20Atmospheric%20Physics%20and%20Evolution | The Extreme-ultraviolet Stellar Characterization for Atmospheric Physics and Evolution (ESCAPE) mission aims to find environments beyond Earth's solar system that might host planets with thick atmospheres to support life.
The long-term stability of exoplanetary atmospheres depends critically on the extreme-ultraviolet (EUV) flux from the host star. The EUV flux likely drives the demographics of the short-period planet population as well the ability for rocky planets to maintain habitable environments long enough for the emergence of life. ESCAPE is an astrophysics Small Explorer proposed to NASA that employs extreme- and far-ultraviolet spectroscopy (80 – 1650 Å) to characterize the high-energy radiation environment in the habitable zones (HZs) around nearby stars.
Mission objective
ESCAPE provides the first comprehensive study of the stellar EUV environments that control atmospheric mass-loss and determine the habitability of rocky exoplanets. ESCAPE's prime mission is driven by two spectroscopic surveys: 1) a broad survey of EUV and FUV flux from 200 nearby (d < 100 pc) F, G, K, and M stars, providing direct input into atmospheric evolution models. The mission targets stars with a range of ages and activity levels, and places an emphasis on stars with known exoplanets. 2) A deep monitoring survey (~2 weeks per star) of 24 targets-of-interest to measure the stellar flare frequency distribution and constrain the coronal mass ejection (CME) rate and high-energy particle fluence from these objects. Together, these surveys provide the crucial stellar drivers that regulate habitable environments on planets targeted by upcoming atmospheric characterization missions, from James Webb Space Telescope to Large Ultraviolet Optical Infrared Surveyor.
Science instrument
The ESCAPE Hettrick-Bowyer telescope comprises a grazing-incidence mirror that focus ultraviolet light through a spectral filter, where a secondary mirror module directs light to a set of grazing-incidence gratings and a set of normal-incidence gratings that disperse light as spectra onto the microchannel plate detector. This ultimately results in spectra ranging from 80 Å to 825 Å (EUV) and from 1280 Å to 1650 Å (FUV) with 1 Å resolution. Once downlinked and processed, these measurements will be accessible on Mikulski Archive for Space Telescopes (MAST).
Construction
ESCAPE is being designed and built by several institutions, led by Principal Investigator Kevin France at the Laboratory for Atmospheric and Space Physics (LASP), a research institute at University of Colorado Boulder.
LASP is responsible for the overall project, instrument design, instrument integration, mission operations, and science data processing.
Ball Aerospace provides the spacecraft bus, integrates it with the telescope, and performs spacecraft level environmental testing.
Marshall Space Flight Center and Smithsonian Astrophysical Observatory jointly manufacture, assembles, and align the concentric, grazing incidence mirrors optimized for ESCAPE's observing bandpass.
Pennsylvania State University provides the custom gratings that disperse incoming light into spectra.
University of California Berkeley provides the specialized detector.
References
External links
Satellites orbiting Earth
Astronomical surveys
Explorers Program
Proposed spacecraft | Extreme-ultraviolet Stellar Characterization for Atmospheric Physics and Evolution | [
"Astronomy"
] | 628 | [
"Astronomical surveys",
"Works about astronomy",
"Astronomical objects"
] |
67,130,460 | https://en.wikipedia.org/wiki/Barry%20Sinervo | Barry R. Sinervo (1961–2021) was a behavioral ecologist and evolutionary biologist. He was a full professor at University of California Santa Cruz where his research interests included game theory, climate change, herpetology, and animal behavior. One of his major discoveries was of a rock-paper-scissors game in side-blotched lizard mating behaviour. He also discovered evidence of the Baldwin effect in the side-blotched lizard. Sinervo was born in Port Arthur, Ontario, Canada, and educated at Dalhousie University, Nova Scotia, and the University of Washington, Seattle. He died from cancer at age 60 on March 15, 2021.
Honors
A species of lizard was named after Sinervo, Phymaturus sinervoi Scolaro et al., 2012.
References
1961 births
2021 deaths
University of California, Santa Cruz faculty
Ethologists
Evolutionary biologists
American herpetologists | Barry Sinervo | [
"Biology"
] | 191 | [
"Ethology",
"Behavior",
"Ethologists"
] |
67,131,807 | https://en.wikipedia.org/wiki/Popularity%20of%20text%20encodings | A number of text encoding standards have historically been used on the World Wide Web, though by now UTF-8 is dominant in all countries, with all languages at 95% use or usually rather higher. The same encodings are used in local files (or databases), in fact many more, at least historically. Exact measurements for the prevalence of each are not possible, because of privacy reasons (e.g. for local files, not web accessible), but rather accurate estimates are available for public web sites, and statistics may (or may not accurately) reflect use in local files. Attempts at measuring encoding popularity may utilize counts of numbers of (web) documents, or counts weighed by actual use or visibility of those documents.
The decision to use any one encoding may depend on the language used for the documents, or the locale that is the source of the document, or the purpose of the document. Text may be ambiguous as to what encoding it is in, for instance pure ASCII text is valid ASCII or ISO-8859-1 or CP1252 or UTF-8. "Tags" may indicate a document encoding, but when this is incorrect this may be silently corrected by display software (for instance the HTML spec says that the tag for ISO-8859-1 should be treated as CP1252), so counts of tags may not be accurate.
Popularity on the World Wide Web
UTF-8 has been the most common encoding for the World Wide Web since 2008. , UTF-8 is used by 98.5% of surveyed web sites (and 99.2% of top 100,000 pages and 98.8% of the top 1,000 highest-ranked web pages), the next most popular encoding, ISO-8859-1, is used by 1.1% (and only 14 of the top 1,000 pages). Although many pages only use ASCII characters to display content, very few websites now declare their encoding to only be ASCII instead of UTF-8.
Virtually all countries and over 97% all of the tracked languages have 95% or more use of UTF-8 encodings on the web. See below for the major alternative encodings:
The second-most popular encoding varies depending on locale, and is typically more efficient for the associated language. One such encoding is the Chinese GB 18030 standard, which is a full Unicode Transformation Format, still 95.7% of websites in China and territories use UTF-8 with it (effectively) the next popular encoding. Big5 is another popular non-UTF encoding meant for traditional Chinese characters (though GB 18030 works for those too, is a full UTF), and is next-most popular in Taiwan after UTF-8 at 96.7%, and it's also second-most used in Hong Kong, while there as elsewhere, UTF-8 is even more dominant at 98.3%. The single-byte Windows-1251 is twice as efficient for the Cyrillic script and still 95.6% of Russian websites use UTF-8 (however e.g. Greek and Hebrew encodings are also twice as efficient, and UTF-8 has over 99% use for those languages). Korean, Chinese and Japanese language websites also have relatively high non-UTF-8 use compared to most other countries, with Japanese UTF-8 use at 98.6% the rest use the legacy EUC-JP and/or Shift JIS (actually decoded as its superset Windows-31J) encodings that both are used about as much. South Korea has 94.8% UTF-8 use, with the rest of websites mainly using EUC-KR which is more efficient for Korean text.
Popularity for local text files
Local storage on computers has considerably more use of "legacy" single-byte encodings than on the web. Attempts to update to UTF-8 have been blocked by editors that do not display or write UTF-8 unless the first character in a file is a byte order mark, making it impossible for other software to use UTF-8 without being rewritten to ignore the byte order mark on input and add it on output. UTF-16 files are also fairly common on Windows, but not in other systems.
Popularity internally in software
In the memory of a computer program, usage of UTF-16 is very common, particularly in Windows but also cross-platform languages and libraries such as JavaScript, Python, and Qt. Compatibility with the Windows API is a major reason for this. Non-Windows libraries written in the early days of Unicode also tend to use UTF-16, such as International Components for Unicode.
At one time it was believed by many (and is still believed today by some) that having fixed-size code units offers computational advantages, which led many systems, in particular Windows, to use the fixed-size UCS-2 with two bytes per character. This is false: strings are almost never randomly accessed, and sequential access is the same speed in both variable- and fixed-size encodings. In addition, even UCS-2 was not "fixed size" if combining characters are considered, and when Unicode exceeded 65536 code points it had to be replaced with the non-fixed-sized UTF-16 anyway.
Recently it has become clear that the overhead of translating from/to UTF-8 on input and output, and dealing with potential encoding errors in the input UTF-8, overwhelms any benefits could offer. So newer software systems are starting to use UTF-8. The default string primitive used in newer programing languages, such as Go, Julia, Rust and Swift 5, assume UTF-8 encoding. PyPy also uses UTF-8 for its strings, and Python is looking into storing all strings with UTF-8. Microsoft now recommends the use of UTF-8 for applications using the Windows API, while continuing to maintain a legacy "Unicode" (meaning UTF-16) interface.
References
Character encoding
Unicode Transformation Formats
Character sets | Popularity of text encodings | [
"Technology"
] | 1,256 | [
"Natural language and computing",
"Character encoding"
] |
69,991,713 | https://en.wikipedia.org/wiki/Fyodor%20Urnov | Fyodor Dmitriyevich Urnov (; born 1968) is a Russian-born biomedical researcher and who has played a leading role in the field of genome editing. He is a Professor of Genetics, Genomics, and Development at the University of California, Berkeley and Director of the Center for Translational Genomics at the university's Innovative Genomics Institute. In 2005 Urnov and his colleagues coined the term "genome editing" and demonstrated the first use of ZFNs to edit DNA in human cells. Urnov is considered a pioneering figure in the field of genome editing and his work has been cited widely.
Early life and education
Fyodor Urnov was born in Soviet Russia to a linguist mother and a literary critic father. He was raised in Moscow. Urnov's father frequently purchased him books; on his 12th birthday, Urnov received a copy of James D. Watson's book The Double Helix. The book helped to spark Urnov's early interest in life sciences.
Urnov attended Moscow State University, where he received his undergraduate degree in biology in 1990. Following the fall of the Iron Curtain, Urnov applied to graduate schools in the United States. He attended Brown University for doctoral studies where he worked as a researcher in the laboratory of Susan Gerbi. He received his Ph.D. from Brown in 1996.
Career
After graduating, Urnov worked with DNA in the laboratory of Alan Wolffe at the National Institutes of Health. In 2000, Urnov followed Wolffe to Sangamo Therapeutics where he had been recruited as Chief Scientific Officer. Shortly after moving to the San Francisco Bay Area, Urnov was offered an adjunct position as a lecturer at the University of California, Berkeley.
In 2005 Urnov's team at Sangamo demonstrated the first use of ZFNs to edit DNA in human cells and coined the term "genome editing."
In 2019 Urnov joined UC Berkeley as Professor of Genetics, Genomics, and Development and Director of the Center for Translational Genomics at the Innovative Genomics Institute.
Honors and awards
2024 Horace Mann Medal, Brown University
References
External links
Living people
Genome editing
History of biotechnology
Scientists from Moscow
Moscow State University alumni
Brown University alumni
University of California, Berkeley College of Letters and Science faculty
1968 births | Fyodor Urnov | [
"Engineering",
"Biology"
] | 459 | [
"Genetics techniques",
"History of biotechnology",
"Genetic engineering",
"Genome editing"
] |
69,993,032 | https://en.wikipedia.org/wiki/Sir%20Michael%20Uren%20Hub | The Sir Michael Uren Hub is a 13-storey building on the north side of the elevated A40 Westway in London, designed by Allies and Morrison for the purpose of Imperial College's biomedical engineering research. It contains a 160-seat auditorium, social space, cleanrooms, and futuristic outpatients. It is named for engineer Sir Michael Uren and built using his engineered cement substitute, ground granulated blast furnace slag (GGBS).
It houses the School of Public Health's Environmental Research Group, the Musculoskeletal Laboratory (MSk lab) and the National Heart and Lung Institute (NHLI).
Location
The Sir Michael Uren Hub is situated on Wood Lane, Shepherd's Bush, London. To its north is a 34-storey tower, to its east is an incubator building, and to its south is an elevated section of the A40 Westway.
History
In 2014 Imperial College London announced that it was to build a biomedical engineering centre supported by a £40 million donation from Sir Micheal Uren and his foundation, at Imperial West, the College's 25-acre research and innovation campus in White City, west London. The purpose was to house Imperial's biomedical and healthcare researchers, engineers, scientists and clinicians, along with spin-out companies, in one building.
Work on the site began in January 2017. It officially opened in December 2020.
Design
The 13-storey Hub was designed by architects Allies and Morrison, and the project was managed by Turner & Townsend, with mechanical and engineering consultants Buro Happold. Autodesk Revit provided the CAD software, and the building was inspected by Bureau Veritas. ISG Ltd was the contractor.
Structural features
The building has a triangular base and covers 18,150 square metres. It has two long sides, covered in 1,300 GGBS containing four metre high vertical precast concrete fins, of which there are nine types. GGBS, a waste by-product of coal-fired power stations, was developed by Uren's company as a substitute for cement which produces a fraction of the carbon emissions. The fins act to shade from the sun.
It contains a 160-seat auditorium, social space, cleanrooms, and futuristic outpatients. It houses the School of Public Health's Environmental Research Group led by Frank Kelly, the MSk Lab led by Justin Cobb and Alison McGregor, the Dementia Research Institute, the Centre for Cardiovascular Bioengineering, and 20 companies. Members of the National Heart and Lung Institute (NHLI) occupy space on the ninth floor.
It has space for functions and exhibitions in the main entrance, adjacent to the ground floor cafe. The auditorium and its foyer on the lower ground floor can be accessed via the main entrance and the research floors above can be accessed via secure entry. A discrete second entrance near a vehicle drop-off - pick-up point serves the clinical facility. There are toilets on all floors.
Gallery
References
External links
Research institutes in London
Engineering research institutes
2020 establishments in England
Laboratories in the United Kingdom
High-tech architecture
Modern architecture in the United Kingdom | Sir Michael Uren Hub | [
"Engineering"
] | 639 | [
"Engineering research institutes"
] |
69,994,706 | https://en.wikipedia.org/wiki/Bruceantin | Bruceantin is a chemical compound that was first isolated from the plant Brucea antidysenterica in 1973. Chemically, it is classified as a secotriterpenoid and a quassinoid.
Bucreantin has attracted interest as a potential antitumor drug because of its antineoplastic activity. It inhibits the peptidyl transferase elongation reaction, resulting in decreased protein and DNA synthesis. Bruceantin also has antibiotic, antiamoebic, and antimalarial activity.
Phase I and II clinical trials were conducted for the treatment of metastatic breast cancer and malignant melanoma, but tumor regression was not observed and clinical development was terminated.
References
Quassinoids
Heterocyclic compounds with 5 rings
Methyl esters | Bruceantin | [
"Chemistry"
] | 165 | [] |
69,994,997 | https://en.wikipedia.org/wiki/CrysTBox | CrysTBox (Crystallographic Tool Box) is a suite of computer tools designed to accelerate material research based on transmission electron microscope images via highly accurate automated analysis and interactive visualization. Relying on artificial intelligence and computer vision, CrysTBox makes routine crystallographic analyses simpler, faster and more accurate compared to human evaluators. The high level of automation together with sub-pixel precision and interactive visualization makes the quantitative crystallographic analysis accessible even for non-crystallographers allowing for an interdisciplinary research. Simultaneously, experienced material scientists can take advantage of advanced functionalities for comprehensive analyses.
CrysTBox is being developed in the Laboratory of electron microscopy at the Institute of Physics of the Czech Academy of Sciences. For academic purposes, it is available for free. As of 2022, the suite has been deployed at research and educational facilities in more than 90 countries supporting research of ETH Zurich, Lawrence Berkeley National Laboratory, Max Planck Institutes, Chinese Academy of Sciences, Fraunhofer Institutes or Oxford University.
Suite
As a scientific tool, CrysTBox suite is freely available for academic purposes, it supports file formats widely used in the community and offers interconnection with other scientific software.
Availability
CrysTBox is freely available on demand for non-commercial use by non-commercial subjects. The only safe way to download CrysTBox installers is via a request form on the official website. Commercial use is not allowed due to the license of MATLAB used for CrysTBox compilation.
Notable research and users
Besides education, CrysTBox is mainly used in research with fields of application spanning from nuclear research to archaeology and paleontology. Among others, the suite was employed in development of additive manufacturing (including 3D printed biodegradable alloys, metallic glass or high-entropy alloys), resistant coatings, laser shock peening, water cleaning technologies or characterization of 50 million years old flint.
Institutions whose research was supported by CrysTBox include educational facilities such as ETH Zurich, University of California, Uppsala University, Oxford University, University of Waterloo, Indian Institute of Technology, Nanyang Technological University or University of Tokyo as well as research institutes like Max Planck Institutes, Chinese Academy of Sciences, Fraunhofer Institutes or US national laboratories (NL) such as Oak Ridge NL, Lawrence Berkeley NL, Idaho NL and Lawrence Livermoore NL.
Limitations and disadvantages
CrysTBox is compiled to a stand-alone installers using MATLAB Compiler. Therefore, 1-2 GB of MATLAB libraries are installed together with the toolbox.
The diffraction simulation used in cellViewer is based on kinematic diffraction theory. This allows for a real-time response to user interaction, but it does not cover advanced diffraction features like double diffraction covered by dynamical diffraction theory, even though some phenomena caused by multiple electron-matter interactions are visualized by CrysTBox - for instance Kikuchi lines.
The analytical tools provide correction for scale calibration imperfections, but does not provide adjustment for image distortions such as elliptical distortion. If high-accuracy measurement is needed or if the distortion exceeds standard levels, appropriate tools should be applied prior to the analysis.
Crystallographic visualization tools
In order to visualize functional relations and provide better understanding of experimental data, the graphical interface emphasize user interactivity and functional interconnection. There are two visualization tools in the suite: one depicting single material while another being focused on intergrowths of two different materials.
cellViewer - single crystal visualization
CellViewer allows to visualize the sample material in four modes widely used in material research:
3D model of atomic structure (direct space),
simulated diffraction pattern (reciprocal space),
stereographic projection (projection of 3D space of crystallographic planes and directions to 2D),
inverse pole figure (defined part of stereographic projection).
Graphical user interface provides user with two interactive views side by side. These views can display arbitrary combination of the four aforementioned visualization modes allowing to perceive their mutual relations. For instance, rotation of the atomic structure in direct space leads (if set so) to an instant update of the simulated diffraction pattern. If any diffraction spot is selected, corresponding crystallographic planes are shown in the unit cell etc. Such interconnections are implemented for each pair of the four available visualization modes. The electronic visualization allows to simplify understanding of widely used, yet less intuitive representations such as the inverse pole figure. For instance by drawing the coloured triangle of the inverse pole figure into the stereographic projection or to the more intuitive 3D atomic structure.
- intergrowth visualization
The allows for visualization of two misoriented materials and their interface such as crystal twins or grain boundaries. The user interface provides three views: two smaller views, each depicting one unit cell of selected material and orientation, and a larger view depicting an appropriate interface of the two structures. The interface can be visualized in four modes:
3D model of both unit cells,
wire-frame model of both unit cells,
cross section of the interface,
bulk representation (up to several hundred atoms).
All three views in the user interface are functionally interconnected. If the content of one view is rotated by the user, the other views follow. If a crystallographic plane or direction is selected in one view, it is shown in other views and corresponding crystallographic indices are stated. The tool also allows to highlight coincident site lattice or calculate the list of planes and directions which are parallel or nearly parallel in the two misoriented materials.
Automated analysis of TEM images
CrysTBox offers tools for automated processing of diffraction patterns and high-resolution transmission electron microscope images. Since the tools employ algorithms of artificial intelligence and computer vision, they are designed to require minimal operator effort providing higher accuracy compared to manual evaluation. Four analytical tools can be used to index diffraction patterns, measure lattice constants (distances and angles), sample thickness etc. Despite the high level of automation, the user is able to control the whole process and perform individual steps manually if needed.
diffractGUI - HRTEM and diffraction processing
DiffractGUI allows for an automated analysis of diffraction patterns and high-resolution images of single crystal or limited number of crystallites. It is able to determine crystal orientation, index individual diffraction spots and measure interplanar angles and distances in picometric precision. The input image may depict:
selected area diffraction pattern,
high-resolution image,
nanodiffraction pattern or
convergent beam electron diffraction.
The input image is processed in the following steps:
Preprocessing with accordance to the settings and image nature (resolution and noise reduction, Fourier transform for direct space images etc.).
Detection of diffraction reflections at various scales (difference of Gaussians typically used for spot detection, Hough transform for CBED disk detection).
The strongest detections are selected across the scale space.
A regular lattice is fit to the set of the strongest detections using RANSAC algorithm.
Lengths and angles of the lattice basis vectors are measured.
Crystal lattice orientation is determined and diffraction reflections are identified using theoretical parameters of the sample material.
Compared to human evaluation, considers tens or even hundreds of diffraction spots at once and, therefore, can localize the pattern with sub-pixel precision.
ringGUI - ring diffraction analysis
RingGUI allows for an automated processing of ring diffraction images of polycrystalline or powder samples. It can be used to identify the diffraction rings, quantify the interplanar distances and thus characterize or identify the sample material. With known material, it can assist in microscope calibration. The input image is processed as follows:
beam-stopper detection,
localization of the ring center,
quantification of the diffraction profile and estimation of its background intensity,
identification of the rings in the image (peaks in the profile).
The results can be further processed and visualized in two interactive, functionally interconnected graphical elements:
Interactive diffraction image – allows the user to improve readability of the diffraction image by removing the beam-stopper, subtracting the background, revealing faint or spotty rings or by crystallographic identification of the depicted rings.
Diffraction profile – circular average of the image intensities depicts the peaks corresponding to the rings and their match with theoretical values known for given sample material.
Both, the diffraction image as well as diffraction profile can be used to select diffraction rings with a mouse click. The corresponding ring is then highlighted in both graphical representations and details are listed.
twoBeamGUI - sample thickness estimation
Sample thickness can be estimated using twoBeamGUI from a convergent beam electron diffraction pattern (CBED) in two beam approximation. The procedure is based on an automated extraction of the intensity profile across the diffracted disk in the following steps:
diffraction disk radius is determined using multi-scale Hough transform,
the transmitted and diffracted disks are localized and the reflection is indexed,
the disks are horizontally aligned, cropped out and profiles are measured across the disks,
the profile across the diffracted disk is matched with a series of profiles automatically simulated for given material, reflection and specified thickness range.
Once the procedure is completed, the measured profile and the most similar simulated profile are displayed with the diffracted disk on the background. This allows the user to verify correctness of the automated estimate and easily check the similarity of other intensity profiles within the specified thickness range.
gpaGUI - geometric phase analysis
The tool called gpaGUI provides an interactive interface for geometric phase analysis. It allows to generate 2D maps of various crystallographic quantities using high-resolution images.
Since the geometric phase analysis is performed in frequency domain, the high-resolution image needs to be transformed into frequential representation using Fourier transform. Mathematically, the frequential image is a complex matrix with the size equal to the original image. Crystallographically, it can be seen as an artificial diffraction pattern of the original image depicting intensity peaks corresponding to the crystallographic planes present in the original image. After performing desired calculations, the frequential representation can be transformed back to the original spatial domain using inverse Fourier transform.
Various crystallographic analyses can be performed using the frequential image. If it is filtered so that only the information from a region close to a particular diffraction spot is used (the rest is set to zero), a filtered direct image obtained by inverse Fourier transform then depicts only the planes corresponding to the selected diffraction spot. Moreover, due to its complex nature, the frequential image can be used to calculate amplitude and phase. Together with a vector of one crystallographic plane depicted in the image, they can be used to generate a 2D map interplanar distance of given plane. If two vectors of non-parallel planes are known, the method can be used to generate maps of strain and displacement.
Graphical user interface of gpaGUI is vertically divided into two halves, each of which contains:
Diffractogram preview allowing to select one diffraction spot corresponding to a crystallographic plane.
Visualization of a selected quantity (input image, filtered image or one of the maps mentioned above) allowing to select point of interest or region of interest for further analysis.
Results of detailed analysis of point or region of interest. The point analysis allows the user to select any pixel of the visualized map to see exact values of the particular pixel and its closest neighbourhood. If analysis of broader area is needed, a polygonal region can be outlined in the map allowing to enumerate its statistical details: mean, standard deviation, median, minimum, maximum and total area of the polygon.
Since each half of the interface allows to specify one crystallographic plane, gpaGUI allows to calculate all the aforementioned crystallographic quantities including those which require two vectors. Precision and repeatability of the whole analysis relies on accuracy of the diffraction peak localization. To overcome inaccuracy of manual peak localization (with a mouse click), gpaGUI provides a possibility to process the input image with in order to accurately localize and index the peaks.
See also
Transmission electron microscope
Selected area diffraction
Convergent beam electron diffraction
High-resolution transmission electron microscopy
Geometric phase analysis
Electron crystallography
Crystal structure
Computer vision
Artificial intelligence
Fourier transform
Difference of gaussians
Hough transform
RANSAC
Czech Academy of Sciences
Notes
References
External links
Request form to obtain CrysTBox
Czech Academy of Sciences
Institute of Physics of the Czech Academy of Sciences
Crystallography Open Database
Inorganic Crystal Structure Database
Crystallography
Science education software
Science software
Electron microscopy
Computer vision software
Visualization software | CrysTBox | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 2,620 | [
"Electron",
"Electron microscopy",
"Materials science",
"Crystallography",
"Condensed matter physics",
"Microscopy"
] |
69,995,103 | https://en.wikipedia.org/wiki/Jan%20Sundell | Jan Sundell (10 July 1943 – 27 May 2019) was a Swedish Professor in Building Science, affiliated with Technical University of Denmark, University of Texas at Tyler, USA, Tsinghua- and Tianjin Universities in China.
Biography
Jan Sundell was born and grew up in Östersund, in the northern Swedish province of Jämtland. In 1961 he graduated from Högre Allmäna Läroverket. After military service, in 1963, he moved to Stockholm to attend Royal Institute of Technology in Stockholm and for studies at Stockholm University. After obtaining a master's degree in engineering from KTH, he worked for the Swedish authorities, with building codes and regulations for building ventilation. He worked at the National Board of Urban Planning and Building and the National Board of Occupational Safety and Health, where he was Head of section for Ventilation and Thermal Climate. In 1994 he defended his PhD-thesis in medical sciences at Karolinska Institutet.
Both as a scientist and a government official he was a driving force in developing the research area of Indoor Air. He took part in founding the International Society of Indoor Air Quality and Climate (ISIAQ), and conferences Indoor Climate in Copenhagen 1978, Indoor Air in Stockholm 1984 and Healthy Buildings in Stockholm 1988, and he served as editor in chief for the Indoor Air Journal. He initiated and took active part in large national and international studies like the Dampness in Buildings and Health (DBH) in Sweden where the same concept later on have been used in Bulgaria, Denmark, USA, Singapore, Taiwan, and China, as well as the SELMA-study (Swedish Environmental Longitudinal, Mother and child, Asthma and allergy study). He published more than 150 peer reviewed articles. Over time he served on many committees and working groups, such as ASHRAE Environmental Health Committee, WHO - expert groups on indoor Air Quality and Health, and European Multidisciplinary Scientific Consensus Group on Ventilation and Health. He won several prizes, among them The Rockwool Prize in 2004 and the Pettenkofer Gold Medal in 2011.
References
1943 births
2019 deaths
Swedish scholars and academics
People from Östersund
People from Jämtland
Building defects
KTH Royal Institute of Technology alumni
Academic staff of the Technical University of Denmark
University of Texas at Tyler faculty
Academic staff of Tsinghua University | Jan Sundell | [
"Materials_science"
] | 465 | [
"Mechanical failure",
"Building defects"
] |
69,995,164 | https://en.wikipedia.org/wiki/The%20Secret%20Guide%20to%20Computers | The Secret Guide to Computers is a book on computer hardware and software techniques by Russ Walter.
The book was written to be useful in both teaching and professional environments. Its goal is to describe everything necessary to become a "computer expert," covering philosophies, technicalities, hardware, software, theory, and practice.
Walter shares his telephone number for readers of the book to ask questions 24 hours a day.
Editions
, there are 34 editions of the book.
Details:
The original edition, now called "edition zero," was written in 1972. It was 17 pages about how to write programs in BASIC. The 7th edition, written in 1976, was the first edition to actually use the title "The Secret Guide to Computers."
Some editions are multi-volume sets.
Table of contents
All editions are self-published by the author, Russell M. Walter (nicknamed "Russ"), but other publishers have reprinted their own versions. For example, the 11th edition, written in 1983, was a 2-volume set. The photo (which you see on the right or above) shows a reprint, published by Birkhäuser Boston, of volume 1 of the 11th edition. It includes a different cover and different advertising material than Russ's version. It was Birkhäuser Boston's first edition but a reprint of just part of Russ's 11th edition.
The 31st edition had an expanded title: "Secret Guide to Computers & Tricky Living." That's because it combined "The Secret Guide to Computers" with Russ's other book, "Tricky Living," to form a huge book, 703 pages. That expanded title was used on the 31st edition and all later editions (the 32nd, 33rd, and 34th).
The current edition, the 34th, was published in 2022. Its 703 pages include 42 chapters, organized into 7 mega-chapters: buying (use this book, how to shop, chips, disks, I/O devices software, complete systems), Windows (Windows 10&11, Web, email, security, maintenance, repairs, command prompt), handhelds (pure Android, Samsung's Android, iPad), tricky living (health, daily survival, intellectuals, language, places, Donna's comments, arts, math, government, morals, sex), Microsoft Office (Word, Excel, PowerPoint), programming (Basic, Python, Web-page design, challenges, Visual Basic, Visual C#, exotic languages, assembler), and parting (computer past, your future, resources). Though most of the book was written by Russ, the "Donna's comments" chapter was written instead by his wife (Guang Chun Walter, nicknamed "Donna") and edited by him, so she's a coauthor.
Many earlier editions are still available from Russ, at reduced prices and including many topics omitted from the 34th edition, such as a dozen big 33rd-edition topics (Windows 7 & 8 & 8.1, Internet Explorer, Yahoo Mail, iPhone, Microsoft Publisher&Access, QB64, and Java&APL) and prostitution (most thoroughly in Tricky Living's first edition).
The book's Website, SecretFun.com, includes links to free PDFs of the entire 33rd & 34th editions, plus many other topics, such as how to get printed books directly from Russ and phone him at 603-666-6644 for free help about computers and everything else in life.
References
Computer books
1984 non-fiction books
Birkhäuser books | The Secret Guide to Computers | [
"Technology"
] | 726 | [
"Works about computing",
"Computer books"
] |
69,995,420 | https://en.wikipedia.org/wiki/Personal%20Science | Personal science is a term used by the late psychologist and scientist Seth Roberts, who defined it as: "using science to solve your own problems". Associated fields are self-experimentation and citizen science. The concept has been further developed within the Quantified Self community. The first use of the term in a scientific publication was in 2016, where it was associated with: "an interest in collecting data about their own bodies or lives in order to obtain insights into their everyday health or performance". In 2017, the scientific journal Methods of Information in Medicine published a focus theme on single subject (N-of-1) research design, which also included personal science. The editorial introducing the focus theme is titled "Single Subject (N-of-1) Research Design, Data Processing, and Personal Science" is co-authored by Gary Wolf, who together with Kevin Kelly coined the phrase the quantified self. In the editorial, personal science was described as "self-directed N-of-1 studies". In 2020, Wolf further developed the term together with Martijn de Groot in an article titled "A Conceptual Framework for Personal Science". They defined personal science as "the practice of using empirical methods to explore personal questions". In a 2021 scientific article building on the previous ones, personal science is defined as: "the practice of exploring personally consequential questions by conducting self-directed N-of-1 studies using a structured empirical approach".
History
The history of personal science is derived from several sources, one of which is the 1958 book Personal knowledge: Towards a post-critical philosophy by Michael Polanyi. His work especially highlighted the tacit and subjective dimensions of conventional scientific practices. Building on Polanyi's work, Martin and Brouwer introduced the term personal science in the 1993 article Exploring personal science, as an approach for characterizing scientific practice for young students. They emphasized that “science is not simply rational and objective but that the inquiring person is an integral part of the enquiry.”
In 2024, a MediaWiki-based knowledge management system that had been co-designed by and for personal science practitioners was published by a team of researchers.
See also
Quantified self
Self-experimentation
Seth Roberts
Human enhancement
eHealth
References
Health informatics | Personal Science | [
"Biology"
] | 469 | [
"Health informatics",
"Medical technology"
] |
69,996,259 | https://en.wikipedia.org/wiki/List%20of%20animals%20with%20horns%20or%20tusks | This is a list of animals that have hard permanent pointed projections on their head.
Horns
Horns are projections from the top of the head. True horns are found mainly among:
Ruminant artiodactyls
Antilocapridae (pronghorns)
Bovidae (cattle, goats, antelopes etc.).
Giraffidae: Giraffids have a pair of skin covered bony bumps on their heads, called ossicones.
Cervidae: Most deer have antlers, which are not true horns due to lacking a bone core and made of keratin.
Rhinocerotidae: The "horns" of rhinos are made of keratin and lack a bone core.
Tusks
Tusks are pointed elongated teeth that protrude from the mouth and sometimes resemble horns.
Elephants
Walruses
Warthogs
Narwhals
Lists of animals | List of animals with horns or tusks | [
"Biology"
] | 188 | [
"Lists of biota",
"Lists of animals",
"Animals"
] |
69,997,187 | https://en.wikipedia.org/wiki/Jinhua%20Ye | Jinhua Ye is a Chinese chemist who is a professor at the National Institute for Materials Science in Tsukuba. Her research considers high-temperature superconductors for photocatalysis. She was elected Fellow of the Royal Society of Chemistry in 2016 and has been included in the Clarivate Analytics Highly Cited Researcher every year since then.
Early life and education
Ye became interested in science fiction as a child. She was particularly interested in a story by Ye Yonglie that included a castle made from diamond. Ye learned that photocatalysis could split water into hydrogen and oxygen. She then became inspired by Jules Verne's The Mysterious Island,I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable. She studied chemistry at the Zhejiang University. After completing her undergraduate degree, she moved to Japan, where she joined the University of Tokyo. After earning her doctorate in 1990, she joined Osaka University as a research associate.
Research and career
In 1991, Ye joined the National Institute for Materials Science. She was made Director of Photocatalytic Materials Center in 2006 and Director of Environmental Remediation Materials in 2011.
Ye has dedicated her career to the realization of artificial photosynthesis. She is particularly interested in the development of materials that harvest the most sunlight. Ye has studied the reaction mechanisms, and, in an effort to overcome harsh reaction kinetics, has worked on the careful construction of interfaces. In particular, Ye has developed nano-structured surfaces that enhance reactivities, and, using localized surface plasmon resonance, broaden the spectral range of her photocatalytic materials.
Ye was elected Fellow of the Royal Society of Chemistry in 2016. In 2022, she was included by the American Chemical Society Energy Letters in their list of the world's leading women scientists in energy research.
Selected publications
References
Chinese women chemists
Living people
Year of birth missing (living people)
University of Tokyo alumni
Zhejiang University alumni
Fellows of the Royal Society of Chemistry
Photochemists
Osaka University | Jinhua Ye | [
"Chemistry"
] | 440 | [
"Photochemists",
"Physical chemists"
] |
69,998,614 | https://en.wikipedia.org/wiki/TVE%20test%20card | The TVE colour test card (Spanish: Carta de ajuste en color de TVE) was an electronic analogue TV test card adopted by Televisión Española with the introduction of PAL colour broadcasts in 1975. It is notable for its unique design, created by the Danish engineer (1939–2011) in 1973, under the supervision of Erik Helmer Nielsen at the Philips TV & Test Equipment laboratory in Amager, south of Copenhagen, the same team that developed the popular Philips PM5544 test pattern. It replaced a previous black and white version developed by Eduardo Gavilán.
The test card was considered part of the regular TV schedule, figuring among daily program listings published in newspapers and magazines. It was said to be the most viewed program in some days due to people watching the test card while waiting for broadcasts to start in the afternoon. It was also relevant in the context of general work strikes, where the test card was sometimes broadcast in place of regular programming, marking it a visible sign of the strike's success.
It was used on several TVE channels, like TVE 1, TVE 2, Canal Clásico, Teledeporte or TVE Internacional.
With the start of continuous 24-hour broadcasting on TVE's channels, the test card was phased out. It stopped being broadcast on La Primera in 1996 and on La 2 in the early morning hours of 6 January 2001, although it continued to be broadcast sporadically on Teledeporte and TVE Internacional until 2005.
Operation and features
As Televisión Española adopted the PAL colour system in 1975, the test card has specific elements that allow proper colour adjustments. Being a creation of the same team behind the Philips PM5544 test card, it has many elements in common with it (like colour and grey bars or castellations), but introduces some differences (for example, different resolution gratings and coloured background rectangle and circle).
There were two generations of the TVE test card. The original was generated by a heavily modified PM5544 which displays the station name at the bottom of the circle using a programmable character generator. From the early 1990s onwards the appearance of the test card changed, with the station name becoming a graphic and clock font now being identical to that of the PM5644 (which was available by that time and likely to explain such changes) thus the original hardware was likely replaced.
Castellations
The alternating white and black boxes around the perimeter are called castellations. They are used to set overscan (castellations should be visible) and check for the low-frequency response of the entire transmission chain.
Grid
The background features a grid composed of perfect squares of 100% intensity white lines.
This element allows:
Verify image geometry (horizontal and vertical size and linearity, cushion or barrel distortion effects);
Adjust CRT convergence (the three electron guns, one for each primary color, need to target the same place);
Adjust CRT focus;
Check CRT color purity when displaying the 50% intensity gray background.
Rectangle
This element is composed of an orange rectangle, framed with a white line, and located at the image center.
It allows for:
Checking proper chrominance delay, essential for good PAL system operation;
Visualizing low-frequency image distortions;
Adjusting maximum color saturation.
Signal values of this element are:
Circle
This element is composed of a light blue circle, also located at the center of the image. With a diameter of 512 lines, it overlaps the rectangle mentioned previously. The circle provides a quick overview of image geometry.
Signal values of this element are:
Box
Located at the top of the circle and composed of 100% white lines, it allows for verification of the low-frequency response of the transmission chain.
Colour bars
Inside the circle, there's a section of colour bars with 75% amplitude and 100% saturation (EBU color bars), that allows checking chrominance parameters on a vectorscope or waveform monitor.
The signal values of these bars are:
Centre Grid
This element is composed of 100% white lines located at the centre of the image, between the colour bars and the greyscale. It helps with image centring adjustment and allows checking for CRT convergence at the centre of the screen.
Greyscale Bars
Beneath the colour bars, there's a greyscale bar with six steps. This allows checking gamma correction of the television receiver, and linearity response of the transmission chain.
The brightness value of each step varies with a ratio of 20%, as follows:
Grating Bars
Located within the circle, the gratings are composed of alternating white and black lines.
Horizontal frequency response (horizontal resolution) can be determined by five frequency gratings of 0.5, 1.25, 2.25, 4.2, and 4.8 MHz. The last two gratings must show interference from the 4.43 MHz PAL colour carrier.
Pulse Signal
A pulse signal bar is placed under the frequency gratings, consisting of a black rectangle with a white vertical line, corresponding to a 2T pulse. This signal shows the status of the transmission chain at high frequencies, as well as ghosting due to signal echoes.
Station Identification
Other elements like TV network identification ("TVE","La Primera","TVE2","Teleporte","Canal Clásico","TVE Internacional"), specific TV channel logos or a clock were usually added to the test pattern.
See also
Philips PM5540
Telefunken FuBK
References
RTVE
Telecommunications-related introductions in 1973
1975 establishments in Spain
2001 disestablishments in Spain
Danish inventions
Test cards
Broadcast engineering | TVE test card | [
"Engineering"
] | 1,168 | [
"Broadcast engineering",
"Electronic engineering"
] |
69,999,082 | https://en.wikipedia.org/wiki/Potentia%20gaudendi | In sexuality studies, potentia gaudendi or orgasmic force is the physical and mental potential (or capacity) for pleasure in a body. The term was coined by philosopher Paul B. Preciado, who says contemporary economies exploit the body by offering services to increase pleasure—such as Viagra and cocaine—which turn it into a commodity. It is similar to jouissance in Lacanian psychoanalysis and libido in Sigmund Freud's works.
Potentia gaudendi is an important concept in Preciado's work, because it underlies his theory of "pornpower": the idea that sex and pornography is part of a larger and interlocking economic system. The ability to desire, or to withhold desire, cannot be transferred; as a result, economies are always in the process of "emotionally engaging people in order to generate value."
References
Citations
Bibliography
Biopolitics
Concepts in social philosophy
Queer theory | Potentia gaudendi | [
"Engineering",
"Biology"
] | 195 | [
"Biopolitics",
"Genetic engineering"
] |
70,001,702 | https://en.wikipedia.org/wiki/Vladimir%20Petrovich%20Mineev | Vladimir Petrovich Mineev (Владимир Петрович Минеев, surname sometimes transliterated as Mineyev; born 9 October 1945 in Moscow) is a Russian theoretical physicist, specializing in condensed matter physics.
Biography
Mineev graduated in 1969 from the Moscow Institute of Physics and Technology and then became a graduate student at Moscow's Landau Institute for Theoretical Physics. There in 1974 he received his Russian Candidate of Sciences degree (Ph.D.) and in 1983 his Russian Doctor of Sciences degree (habilitation). At the Landau Institute of Theoretical Physics, he was a researcher from 1972 to 1991 and a vice-director from 1992 to 1999, as well as holding a chair in theoretical physics from 1991 to 1999. In 1993 and 1994 he organized Landau Institute summer schools. In Grenoble, France at the Institut Nanosciences et Cryogénie of the Commissariat à l'énergie atomique et aux énergies alternatives (CEA), he was in charge of the theory group, Service de physique statistique, magnétisme et supraconductivité (SPSMS), from 1999 to 2006 and is since 2006 a senior scientist. He is both a Russian and French citizen. He has served as a referee for the Proceedings of the National Academy of Sciences, Nature Physics, Physical Review Letters, and many other physics journals.
He has been a visiting scientist in 8 different countries. His visiting appointments at various locations include the Aspen Center for Physics in 1977 and again in 1989, France's IHES in 1978–1979, Finland's Low Temperature Laboratory of Aalto University at various times from 1979 to 1992, Denmark's Niels Bohr Institute in 1980 and again in 1998, Gothenburg's Chalmers University of Technology in 1981, ETH Zurich in 1991 and again in 2003 and 2008, Grenoble's Institut Laue-Langevin in 1993, Florida State University's National High Magnetic Field Laboratory in 1998–1999 and again in 2005, Kyōto's Yukawa Institute for Theoretical Physics in 1999 (as a guest professor), University of Oxford in 2003, both Tel Aviv University and the Weizmann Institute in 2004 and again in 2008, and the USA's Argonne National Laboratory in 2011.
In 1992 he received the Landau Gold Medal for the topological classification of stable defects in ordered media. In 2014 he was awarded the Lars Onsager Prize. His research deals with various problems in solid state physics, especially the theory of superconductivity and its interaction with magnetism.
He has been married since 1976 and has a son and two daughters.
Selected publications
References
External links
(publication list)
1945 births
Living people
Moscow Institute of Physics and Technology alumni
Landau Institute for Theoretical Physics alumni
20th-century Russian physicists
21st-century Russian physicists
20th-century French physicists
21st-century French physicists
Soviet physicists
Condensed matter physicists
Russian theoretical physicists
Aspen Center for Physics people | Vladimir Petrovich Mineev | [
"Physics",
"Materials_science"
] | 613 | [
"Condensed matter physicists",
"Condensed matter physics"
] |
70,003,103 | https://en.wikipedia.org/wiki/V4332%20Sagittarii | V4332 Sagittarii is a nova-like event in the constellation of Sagittarius. It was discovered on February 24, 1994 at an apparent visual magnitude of 8.9 by Japanese amateur astronomer Minoru Yamamoto from Okazaki, Aichi, then confirmed by K. Hirosawa. Initially designated Nova Sagittarii 1994 #1, it was given the variable star designation V4332 Sgr. A spectra of the event taken on March 4 lacked the characteristic features of a classical nova, with the only emission lines being of the Balmer series. Subsequent spectra showed a rapid decline in luminosity and a change of spectral type over a period of five days. By 2003, the object was ~1500 times less luminous than at peak magnitude and showed a spectrum of an M-type star.
The nova-like event V838 Mon and this outburst formed an unusual category of erupting stars. In 2003, N. Soker and R. Tylenda proposed an accretion scenario as an explanation. They noted that a merger of two main sequence stars in a close binary orbit could explain the observed properties, a process now known as a luminous red nova. In this scenario, the decline in brightness and radius of V4332 Sgr was a consequence of the merged stellar envelope undergoing gravitational contraction.
An infrared excess from the object suggests it has a circumstellar disk. The infrared spectrum of this feature showed an absorption band of water ice and a carbon monoxide emission band. By 2010, the stellar component had become concealed by a dusty disk viewed edge-on. This dust includes a significant component of alumina, with growing amounts of magnesia and iron oxide.
See also
V1309 Scorpii
References
Further reading
Luminous red novae
Sagittarius (constellation)
Sagittarii, V4332 | V4332 Sagittarii | [
"Astronomy"
] | 380 | [
"Sagittarius (constellation)",
"Constellations"
] |
70,003,464 | https://en.wikipedia.org/wiki/Omohundro%20Water%20Treatment%20Plant | Omohundro Water Treatment Plant is a municipal water treatment plant located in Davidson County, Nashville, Tennessee on Omohundro Drive.
Built in 1888, the pump station and boiler house were designed by C. K. Colley. Fitted with Holly-Gaskill pumps that transfer 10 million gallons of water per day from the Cumberland River to the City Reservoir on Kirkpatrick's Hill at Eighth Avenue, South.
The steam-powered generators were converted to electricity in 1952. The filtration plant was completed in 1929 after the intake station, stores and pumps. In 1987 it was added to the US National Register of Historic Places.
The plant was threatened during the 2010 Tennessee floods, a devastating flood in Nashville but major damage was avoided with a sandbagging effort.
References
External links
National Register of Historic Places in Nashville, Tennessee
Water treatment facilities
Gothic Revival architecture in Tennessee | Omohundro Water Treatment Plant | [
"Chemistry"
] | 178 | [
"Water treatment",
"Water treatment facilities"
] |
61,828,622 | https://en.wikipedia.org/wiki/Anopodium%20ampullaceum | Anopodium ampullaceum is a species of fungus first discovered by Nils Lundqvist in Sweden, in the year 1964. A. ampullaceum became one of the first few fungi along with Anopodium epile and Podospora dagonerii, to be placed in the new genus Anopodium due to their unique spores that did not suit the description of the spores of the Podospora genus, which P. dagonerii had previously belonged to. The genus Anopodium deviates from other members of the Sordariomycetes class by two spore characteristics; firstly the pedicels of its spore in the apical position, and secondly due to its immature spores having spherical bodies with cylindrical apical regions. As of 1998 all three of these species are now considered to be one species, using the name A. ampullaceum.
History
Anopodium ampullaceum was first discovered in 1964 by N. Lundqvist in Sweden. A. ampullaceum was first discovered on blue hare dung, then lemming dung both in Sweden and was later discovered on rabbit dung in Oise, France. Lundqvist originally believed A. ampullaceum to be a member of the genus Podospora. Upon further investigation of the A. ampullaceum spores Lundqvist concluded that A. ampullaceum along with the two other closely related species he was examining, Anopodium epile and Podospora dagonerii, all belong in the newly formed genus Anopodium. These fungi spores begin as cylindrical or vermiform type hyaline and are non-septate, for this reason they can not be considered as Podospora spores. Lundqvist also believed that these 3 fungal species have evolved independently from a species closely related to the family Lasiosphaeria. Much later on in 1998 M.J. Richardson studied these three fungal species in-depth gathering samples from various regions of Sweden and France. Upon examination of the spores characteristics such as spore length and width and ampullate hair presence, Richardson concluded that these three species can all be considered the same species with the correct name being Anopodium ampullaceum.
Related Species
Anopodium ampullaceum is most closely related to and similar in morphology to A. epile. A. ampullaceum and A. epile differ most in the presence or absence of ampullate hairs of the top region of the perithecium, their spore lengths and widths, and their pedicel shape of the spores. Despite these variation A. ampullaceum and A. epile are still considered to be the same species under the name A. ampullaceum.
Appearance
Anopodium ampullaceum is most commonly characterized by its spores pedicels that face upwards toward the apex of its ascus. Its spores are polar with both an apical and basal side. The A. ampullaceum perithecia where spores are discharged is a non-stromatic, membrane enclosed structure, that is light in colour with a dark neck, and is covered in hair. The A. ampullaceum has a filiform paraphyses. The ascus is uni-tunicated with an invagination on the apical side and an apical ring that is barely visible. A. ampullaceum spores begin their cycle as a single cell with a spherical body and a cylindrical apical end. In the next stage of its cycle the spore becomes a two celled structure with the lower cell swelling into an ellipsoid shape and a dark brown upper cell. The pedicels of the spores have gelatinous bodies, and ampullate hairs on the neck. The ampullate hairs of the pedicels were considered as determinants of A. ampullaceum identification, but after further examination of various samples it was decided that the presence of ampullate hairs was far too variable to be a marker of the fungal species.
Ecology
Anopodium ampullaceum is commonly found in hare and rabbit dung, as it was initially discovered on Blue hare and lemming dung in Sweden. Prior to the merging of the A. ampullaceum fungi with A. epile and P. dagonerii, A. ampullaceum seemed to be restricted to leporid hare dung. By its modern name A. ampullaceum has been found in dung samples from Sweden, France and the United Kingdom.
References
Lasiosphaeriaceae
Fungus species | Anopodium ampullaceum | [
"Biology"
] | 945 | [
"Fungi",
"Fungus species"
] |
61,830,781 | https://en.wikipedia.org/wiki/Thelephora%20terrestris | Thelephora terrestris, commonly known as the common fiber vase or earthfan fungus is an inedible species of fungus in the Basidiomycota phylum.
Taxonomy
This fungus was first described by Jakob Friedrich Ehrhart in 1787.
Description
Thelephora terrestris is present year round, though is mostly seen July to December. As the fruiting body forms, it starts off lighter in colour then turns to a darker shade of brown as it ages. A stalk may not be present, if there is one, it is usually very short. Sometimes the fungus is grown in large colonies. The shape is described as a fan and can grow up to wide. It has been described to have a moldy earth-like smell.
The hyphae of mycorrhizal forms walls that becomes thicker as it ages, while in earlier stages may be spiney. When mating, the hyphae forms clamp connections The spores are purple-brown colour, ellipsoid or angular shape.
The edibility of this fungus is unknown, but it is considered too tough to be worthwhile.
Similar species
Thelephora palmata is comparatively stinky and less widely distributed. T. vialis is more robust; Cotylidia diaphana and Podoscypha petalodes are similar; Hydnellum can appear similar but has teeth below.
Habitat and ecology
Throughout North America and Europe Thelephora terrestris can be found in soil. It is commonly found in sandy soils under pine trees, on roots and twigs.
This ectomycorrhizal fungus forms a symbiotic relationship known as mycorrhizae, especially with Pinus species. It is commonly found in pine forests as well as plant nursery soils world wide. This fungus is known to get water and nutrients from far away and being capable of growing in both low fertility and high fertility soils.
It is a dominant mycorrhizal fungus, re-establishes quickly after disturbances such as forest fire, and is considered stress tolerant.
Outside of the Pinus genus, it is also capable of forming mycorrizha with other trees such as alder, birch, oak, beech, and poplar.
Thelephora terrestris virus 1 (TtV1), which is a mycovirus, can infect this fungus.
Physiology
The full life cycle can be reproduced and studied in a laboratory, both ectomycorrhizal form and mushroom form.
Due to the mycotoxins that the fungi produces, it protects pinus trees from root pathogen Phytophthora cinnamomi.
References
Terrestris
Taxa named by Jakob Friedrich Ehrhart
Fungus species | Thelephora terrestris | [
"Biology"
] | 556 | [
"Fungi",
"Fungus species"
] |
61,832,100 | https://en.wikipedia.org/wiki/Desi%20Namu | Desi Nama ( also: "Jama Nama" - from Persian Jam` Nama meaning "Summing Book") or Vahi Paddhati () is the traditional accounting system developed and used in the Indian subcontinent.
Early forms of this system were reportedly used in India before the double entry book keeping system was developed in Europe (13th century).
History
Early mentions/colonial times
Various books have been written on desi namu from the late 1800s to the 1900s in regional languages.
Adoption of western calendar
In earlier times desi namu was recorded according Vikram Samvat calendar but now it is recorded according to the financial year.
Accounting technique
Debiting and crediting
The sides are reversed images of those used in double entry system. The left-hand side is known as ‘Jama' (Credit) and the right-hand side is known as 'Udhar' (Debit).
The first fold (sals) on each side is used for recording the amount and the remaining three are meant for recording the details of the transaction.
The posting from Rojmel or BethoMel is on the same side of the Ledger. e.g. A has paid Rupees 500. This will be recorded on the Jama side of Rojmel. In the Khatavahi (Ledger) also, this would be recorded on the Jama side of A's Account.
In the Khatavahi under Desi Nama only the amount, the Rojmel Pan (folio) number and the tithi (date) are written. No details about the transactions are given.
Account categories
Accounts are generally divided into three categories: Personal, real and nominal.
Personal accounts
Real accounts
Nominal accounts
Types of account books
Traditional Indian bookkeeping knows many different types of accounts. The following is non-exhaustive list of some important or notable types.
The word Shri is used as an honorific before many account names, e.g. Shri Bhada Khatun (Rent Account).
Main ledger
Journal / Original entry
This book resembles the western style journal but as far as the balance is concerned, it is a Cash Book of the Double Entry System.
Capital account
In case of partnerships, a capital account of each partner is opened and the amount contributed by a partner is credited to his Capital Account.
Branch office account
When the owner of a business or his salesman, munim, or any other employee travels out of station (deshavar), a lump sum is given to him for expenses. This amount is not debited to his personal account, but is debited to Desawar Account.
Disbursements
Small traders debit small expenses of the business to this type of accounts, e.g. postage, stationery, tea and drinks, Muhurt expenses etc. However, in large businesses separate accounts are maintained for such expenses.
Drawings account
Any amount spent for personal expenses of the proprietor is debited to this.
Anonymous payments
or When an amount is received or paid to someone whose name is not to be disclosed, then the amount is debited or credited to "Shah Khate". Similarly when an amount is paid to or received from someone and their name is forgotten, the same in debited or credited to Shree Khate and when the name is remembered, the name of the person is inserted in the blank space.
Timekeeping
Desi Namu system uses months and year of Vikram Samvat which comprises the twelve-month period from Kartik to Aso. Even in this system, the dates according to English calendar are written. (According to Income Tax Law in India, all accounts must be closed annually on 31 March. Hence traders keeping books under Desi Nama also keep their accounting year from 1 April to 31 March now.)
Comparison to western systems
Leaves (pages) can be added or removed as required. This is appropriate for small traders. They can get the benefit of double entry system by making minor changes. Alas, this means that anybody can tamper with them. Hence the bound books with page numbers used in double entry must be used in desi nama also.
There is no system of columnar book-keeping. Where various items are dealt in, it is convenient to have columnar books. e.g. if a person deals in hosiery and cutlery, it will be convenient to have two columns in Jama Nondh for recording separate purchases of these two items.
Vouchers for all transactions are not systematically filed and maintained nor entered into the main ledger (Khatavahi). This makes a detailed audit trail impossible.
It fails to satisfy the requirements of modern times. Particularly, it is not useful for decision-making in modern big business units.
Contemporary use
India
western India [Gujarat, Rajasthan etc.]
Materials
Books
Books are usually covered with red cloth and are hard-bound. Traditionally the transaction lines are entered parallel to the binding. The books in Desi Nama are usually long, double folded and tied with a thick string. The papers are blank, i.e. not ruled. However, in modern times, books of accounts with lined pages are also in use.
Most of the traders keep the first page for worshiping their Gods e.g. Shri Ganeshay Namah or Mahalaxmi Matani Maher Hajo.
Page folding
Each leaf is folded into eight folds. The first four folds are used for jama and the last four folds (Sals) are used for Udhar. Sometimes a leaf is folded into six folds, three on each side meant for Jama and Udhar respectively. Generally, in case of subsidiary books, six folds are kept.
Ink
It was the practice to write accounts in black ink only, but now blue ink has become common.
References
External links
Accounting systems
History of accounting
Accounting in India | Desi Namu | [
"Technology"
] | 1,197 | [
"Information systems",
"Accounting systems"
] |
61,834,357 | https://en.wikipedia.org/wiki/Paola%20Loreti | Paola Loreti is an Italian mathematician, and a professor of mathematical analysis at Sapienza University of Rome.
She is known for her research on Fourier analysis, control theory, and non-integer representations. The Komornik–Loreti constant, the smallest non-integer base for which the representation of 1 is unique, is named after her and Vilmos Komornik.
Loreti earned a laurea from Sapienza University in 1984. Her dissertation, Programmazione dinamica ed equazione di Bellman [dynamic programming and the Bellman equation] was supervised by Italo Capuzzo-Dolcetta.
With Vilmos Komornik, Loreti is the author of the book Fourier Series in Control Theory (Springer, 2005).
References
External links
Home page
Year of birth missing (living people)
Living people
Italian mathematicians
Italian women mathematicians
Sapienza University of Rome alumni
Academic staff of the Sapienza University of Rome
Italian mathematical analysts
Control theorists | Paola Loreti | [
"Engineering"
] | 201 | [
"Control engineering",
"Control theorists"
] |
61,834,594 | https://en.wikipedia.org/wiki/Taiji%20program | The Taiji program is a proposed Chinese satellite-based gravitational-wave observatory. It is scheduled for launch in 2033 to study ripples in spacetime caused by gravitational waves. The program consists of a triangle of three spacecraft orbiting the Sun linked by laser interferometers.
There are two alternative plans for Taiji. One is to take a 20 percent share of the European Space Agency's LISA project; the other is to launch China's own satellites by 2033 to authenticate the ASE project. Like LISA, the Taiji spacecraft would be 3 million kilometers apart, making them sensitive to as similar range of frequencies, although Taiji is proposed to perform better in some of that range.
Program Goal
'Taiji Program' is the ELISA Program proposed by ESA, and the predecessor of the ELISA Program is the LISA Program cooperated by ESA and NASA. Similar to the configuration of the three networking satellites in the LISA Program, the three satellites in the Taiji Program also rotate around their centroid. The centroid also revolves in orbit around the Sun. The difference is that the phases of the LISA system, Earth system and Taiji system are different. With the Earth as the reference, the phase of the LISA system is 20 degrees behind that of the Programet, and the phase of the Taiji system is 20 degrees ahead of that of the Earth. In addition, the Tai Chi Program is part of the proposed space-based gravitational wave observatories Program, the other parts of which are the Chinese Academy of Sciences (CAS) Tianqin Program and the European Space Agency (ESA) Laser Interferometer Space Antenna (LISA) and the Decimal Hertz Interferometer Gravitational-Wave Observatory (DECIGO) led by the Japan Aerospace Exploration Agency (JAXA). In December 2021, a study pointed out that the gravitational wave detection network combined with Taiji and LISA will accurately measure the Hubble constant greater than 95.5% within ten years. Moreover, The LISA-Taiji network has the potential to detect more than twenty stellar binary black holes (sBBHs), for which the error in luminous distance measurement is in the range of 0.05−0.2, and the relative error in sky positioning is in the range of 1−100deg2 In the range.
The main scientific goal of the Taiji Program is to measure the mass, spin and distribution of black holes through the precise measurement of gravitational waves, to explore how intermediate-mass seed black holes develop if dark matter can produce black seed holes, and how enormous and supermassive black holes grow from black seed holes; Look for traces of the earliest generation of stars' genesis, development, and death, give direct restrictions on the intensity of primordial gravitational waves, and detect the polarization of gravitational waves, providing direct observational data for revealing the nature of gravity. Gravitational waves can provide a clear picture of the universe because they are weakly linked to matter, and the information provided can be used in conjunction with information from telescopes and particle detectors. The precise measurement of gravitational waves allows for in-depth and thorough investigation of the universe's large-scale structure, the birth and development of galaxies, and other topics; Better develop and establish a quantum theory of gravity beyond Einstein's general theory of relativity, reveal the nature of gravity, and help understand dark matter, the nature of energy, the formation of black holes, and cosmic inflation, Gravitational waves can transmit information that electromagnetic waves cannot. At the same time, the forward-looking technology developed from this is of great significance for improving the technical level of space science and deep space exploration; It will also play a positive role in applications such as inertial navigation, Earth science, global environmental change, and high-precision satellite platform construction.
Program history
In 2008, the Chinese Academy of Sciences began demonstrating the feasibility of space gravitational wave detection, proposing the "Taiji Program" for China's space gravitational wave detection, and establishing the "single satellite, dual satellite, three satellites" and "three steps" development strategy and road map； and in August 2018, the "Taiji Program" single-satellite program was implemented in the Space Science (Phase II) Strategic Pilot Science and Technology Special Neutral Program and the first step in the three-step process was launched, that is, the Taiji-1 satellite.
On August 31, 2019, Taiji-1 satellite was launched from the Jiuquan Satellite Launch Center. In July 2021, "Taiji-1" has completed all the preset experimental tasks and achieved the highest precision space laser interferometry in China. It has achieved the first full performance verification of the two types of micro-push technology of Microbull-level radiofrequency ion and Hall, and took the lead in realizing the breakthrough of two non-drug control technologies in China.
The optical metrology system and the non-resistance control system, both of which are part of Taiji-2 satellites, were confirmed by the Taiji-1 satellite mission; The mission's success also gave sufficient backing for the creation of Taiji-2 satellite; However, because Taiji-1 satellite only has one satellite, there is no way to test the inter-satellite laser link; The relevant unit expects to launch two satellites (Taiji-2) in 2023-2025 to clear obstacles for Taiji-3 satellites. And it is expected to launch an equilateral triangle gravitational wave detection star group composed of three satellites around 2030.
Program responsibility unit
The scientific application unit and user of Taiji-1 in this Program is UCAS. The Taiji Program and the ground support system are managed by China's National Space Science Center, while the satellite system is developed by the Chinese Academy of Sciences' Institute of Microsatellite Innovation; the Institute of Precision Measurement Science and Technology Innovation, Chinese Academy of Sciences, Institute of Mechanics, Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Changchun Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Singapore University of Science and Technology, Singapore Nanyang Technological University, and the Institute of Precision Measurement Science and Technology Innovation, Chinese Academy of Sciences are among the cooperative units involved in payload development. In addition, the Chinese Academy of Sciences established the gravitational wave cosmic polar laboratory in Hangzhou in April 2021.
References
Astronomical observatories
Gravitational instruments
Interferometric gravitational-wave instruments
Space telescopes
Proposed space probes | Taiji program | [
"Astronomy",
"Technology",
"Engineering"
] | 1,322 | [
"Astronomical observatories",
"Astronomy organizations",
"Gravitational instruments",
"Measuring instruments",
"Space telescopes"
] |
61,835,523 | https://en.wikipedia.org/wiki/Pounamu | Pounamu is a term for several types of hard and durable stone found in the South Island of New Zealand. They are highly valued in New Zealand, and carvings made from pounamu play an important role in Māori culture.
Name
The Māori word is derived from namu, an archaic word that describes blue-green (or 'grue') cognate with Tahitian ninamu. , also used in New Zealand English, in itself refers to two main types of green stone valued for carving: nephrite jade, classified by Māori as , , , and other names depending on colour; and translucent bowenite, a type of serpentine, known as . The collective term pounamu is preferred, as the other names in common use are misleading, such as New Zealand jade (not all pounamu is jade) and greenstone (a generic term used for unrelated stone from many countries). Pounamu is only found in New Zealand, whereas much of the carved "greenstone" sold in souvenir shops is jade sourced overseas.
The Māori classification of pounamu is by colour and appearance; the shade of green is matched against a colour found in nature, and some hues contain flecks of red or brown.
pounamu takes its name from the native freshwater fish Galaxias maculatus, one of the common whitebait species in New Zealand, and is pearly-white or grey-green in colour. It varies from translucent to opaque. Īnanga was the variety most prized by Māori for ornaments and (short handled clubs).
pounamu is highly translucent and has a vivid shade of light green with no spots or flaws. Its name is the Māori word for a person of high rank, and is the rarest variety of pounamu. It was the preferred stone for making toki poutangata (ceremonial adzes) owned by rangatira (Māori chiefs).
pounamu comes shades of rich dark green, often with small dark flecks or inclusions, and is named after the similarly-coloured leaves of the kawakawa tree (Piper excelsum). It is the most common variety of pounamu, and the most used in the manufacture of jewellery today. One of its main sources is the Taramakau River on the West Coast.
is a rare type of kawakawa with small reddish dots or streaks; its name means "weka blood" after the flightless bird Gallirallus australis.
pounamu is olive green and speckled with dark spots, reminiscent of the markings of three species of native freshwater fishes in the genus Galaxias that go by that name.
Flower jade or picture jade is pounamu with cream, yellow, or brown inclusions, from oxidising or weathering in the surface of the stone. Cracks or fissures in the stone can allow iron impurities to enter, and carvers can then make use of the resulting patterns. Flower jade is best known from the Marsden district near Hokitika.
pounamu is translucent like glass, but in a wide range of shades. When viewed against the light it resembles a clear drop of water. The name means "the tears that come from great sorrow", and refers to a Māori legend of a lamenting woman whose tears turned to stone.
Chemistry
Jade is formed from two different stones: jadeite and nephrite. Jadeite (sodium aluminium silicate) has interlocking granular crystals, while nephrite (calcium magnesium silicate) has crystals that are interwoven and fibrous. Jadeite is mostly found in Myanmar, while nephrite is found in Europe, British Columbia, Australia, and New Zealand. New Zealand nephrite contains varying amounts of iron, which account for its range of shades, richness of green, and translucency.
Geological formation and location
Pounamu is generally found in rivers in specific parts of the South Island as nondescript boulders and stones. Pounamu has been formed in New Zealand in four main locations; the West Coast, Fiordland, western Southland and the Nelson district. It is typically recovered from rivers and beaches where it has been transported to after being eroded from the mountains. The group of rocks where pounamu comes from are called ophiolites. Ophiolites are slices of the deep ocean crust and part of the mantle. When these deep mantle rocks (serpentinite) and crustal rock (mafic igneous rocks) are heated up (metamorphosed) together, pounamu can be formed at their contact.
The Dun Mountain Ophiolite Belt has been metamorphosed in western Southland and pounamu from this belt is found along the eastern and northern edge of Fiordland. The Anita Bay Dunite near Milford Sound is a small but highly prized source of pounamu. In the Southern Alps, the Pounamu Ultramafic Belt in the Haast Schist occurs as isolated pods which are eroded and found on West Coast rivers and beaches.
One source of īnanga pounamu at the head of Lake Wakatipu is possibly the only jade mining site in the world with Government protection.
Significance to Māori
Pounamu plays a very important role in Māori culture and is a taonga (treasure). It is and has been an important part of trade between the South Island iwi (tribe) Ngāi Tahu and other iwi. Adze blades made from pounamu were desired for carving of wood, and even with the arrival of metal tools pounamu tools were used. These were often reworked into (stylised human figures worn as pendants) and other taonga when they were no longer useful for carving wood. After the arrival of Ngāi Tahu in the South Island in the middle of the 18th century, the production of pounamu increased. Pounamu crafting and trade was important to the economy of Ngāi Tahu.
Pounamu taonga increase in mana (spiritual power or prestige) as they pass from one generation to another. Pounamu is believed to absorb the mana of its past owners, and some heirloom pieces are named after a former owner in memory of their position and authority. The most prized taonga are those with known histories going back many generations: these are believed to have their own mana and were often given as gifts to seal important agreements.
Pounamu taonga include tools such as (adzes), (chisels), (gouges), (knives), scrapers, awls, hammer stones, and drill points. Hunting tools include (fishing hooks) and lures, spear points, and (leg rings for fastening captive birds); weapons such as ; and ornaments such as pendants (, and ), ear pendants ( and ), and cloak pins. Functional pounamu tools were widely worn for both practical and ornamental reasons, and continued to be worn as purely ornamental pendants () even after they were no longer used as tools.
Pounamu is found only in the South Island of New Zealand, known in Māori as ('The [land of] Greenstone Water') or ('The Place of Greenstone'). In 1997 the Crown handed back the ownership of all naturally occurring pounamu to the South Island iwi Ngāi Tahu (or Kāi Tahu), as part of the Ngāi Tahu Claims Settlement.
Pounamu was of such value to Māori that peace was cemented by the exchange of valuable carved heirlooms, creating what was figuratively called a (door of greenstone), as in the saying (Let conclude a peace treaty that may never be broken, for ever and ever).
Pounamu trails
There were a dozen major pounamu trails used in the trading of pounamu and many more minor routes. Parties of 6 to 12 are thought to have used the tracks in summer, particularly via Harper Pass.
Modern use
Jewellery and other decorative items made from gold and pounamu were particularly fashionable in New Zealand in the Victorian and Edwardian years in the late 19th and early 20th century. It continues to be popular among New Zealanders and is often given as gifts. In 2011, the New Zealand Prime Minister John Key presented the President of the United States, Barack Obama with a (a type of Māori weapon) created from pounamu carved by New Zealand artist Aden Hoglund.
An exhibition curated by Te Papa in 2007 called showcased 200 pounamu items from their collections and linked New Zealand and China through both the geographical location of nephrite and also the high level of artistry achieved in ancient China and then thousands of years later amongst Māori. The exhibition marked 40 years of diplomatic relations between countries when it toured to five venues in China in 2013.
In the 2016 animated movie Moana the central premise is to return the stolen heart of Te Fiti which is manifest in a pounamu stone amulet.
Fossicking for Pounamu is a cultural activity in New Zealand and allowed on designated areas of the West Coast of the South Island () and is limited to what can be carried unaided; fossicking elsewhere in the tribal area is illegal, while nephrite jade can be sourced legally and freely from Marlborough and Nelson. In 2009 David Anthony Saxton and his son Morgan David Saxton were sentenced to two and a half years imprisonment for stealing greenstone, with a helicopter, from the southern West Coast.
Gallery
See also
Greenstone (disambiguation)
Hei-tiki
Lingling-o
References
External links
Photos of 40 Pounamu varieties with accompanying information
Pounamu, Te Rūnanga o Ngāi Tahu
"Pounamu – jade or greenstone" in Te Ara – the Encyclopedia of New Zealand
Examples of pounamu taonga (Māori treasures) from the collection of the Museum of New Zealand Te Papa Tongarewa
First over the Alps: The epic of Raureka and the Greenstone by James Cowan (eText)
Photo of woman wearing a greenstone neck pendant
Photo of greenstone tiki
Photo of greenstone mere
Gemstones
Geology of New Zealand
Hardstone carving
Māori culture
Māori words and phrases
Minerals
Natural resources in Oceania | Pounamu | [
"Physics"
] | 2,105 | [
"Materials",
"Gemstones",
"Matter"
] |
61,835,801 | https://en.wikipedia.org/wiki/Jean-Claude%20Duplessy | Jean-Claude Duplessy, born in 1942, is a French geochemist. He is Director of Research Emeritus at the CNRS and a member of the French Academy of Sciences.
Biography
Jean-Claude Duplessy, a former student of the Ecole Normale Supérieure (Ulm), a physics graduate, is a geochemist. His work has contributed to a better understanding of how the ocean has functioned over the recent history of the Earth. He is a recognized pioneer in rebuilding ocean dynamics through the use of carbon isotopes and foraminiferous shell oxygen in marine sediments. He was one of the first to see the importance of a high quality chronology for a reliable interpretation of measurements related to climate variations in the Earth's past.
Scientific work
He began his research just as the foundations of isotopic geochemistry were beginning to be well established through the work of Harold Urey and Cesare Emiliani in Chicago. The analysis of stable isotopes and natural radioactive elements makes it possible to approach the study of major biogeochemical cycles in an original way and to reconstruct changes in the Earth's climate and environment by applying current principles.
Jean-Claude Duplessy initially focused on the concretions of the caves and demonstrated that they were good recorders of the hydrological cycle and air temperature at the time they were formed. He obtained the first reconstructions of air temperatures and climatic conditions in the south of France for the last millennia and for the previous interglacial period Recently, this type of study has been resumed in Europe due to the development of new dating methods and the study of stalagmites seems open to a great future.
Duplessy turned to the ocean because of its role as a climate regulator and its major impact on biogeochemical cycles, particularly the carbon cycle. His doctoral thesis work has focused on the geochemistry of stable carbon isotopes in the sea. He showed how the distribution of the stable heavy carbon isotope, carbon-13, was governed by biological fractionations related to chlorophyll assimilation by phytoplankton, then by ocean circulation and finally, to a lesser extent, by gas exchanges between the ocean and the atmosphere. All these phenomena, which dominate the carbon cycle in the ocean, are now being taken into account to study the fate of carbon dioxide emitted by human activities.
Duplessy led numerous oceanographic campaigns and showed that variations in the isotopic composition of fossil foraminifera present in the sediments of the various oceans made it possible to reconstruct changes in the isotopic composition of the ocean and ocean circulation on a large scale, which opened a new scientific field, paleo-oceanography. This has grown to the point where there is now an international journal devoted to this discipline, of which he was one of the first associate editors.
He established the first reconstructions of the deep ocean circulation during the height of the last ice age and during the last interglacial period. This has led him to highlight a disruption in the functioning of the ocean: the North Atlantic deep water disappears under glacial conditions, accompanied by a general slowdown in large-scale ocean circulation, the intensity of the Gulf Stream and the heat flux transported by the Atlantic Ocean to the coasts of Western Europe.
The deep waters of the world ocean are formed by convection and diving of dense surface waters during winter periods. To understand the causes of changes in deep ocean circulation, it was necessary to develop a method to reconstruct not only the temperature (which was already known), but also the salinity of surface waters in the past. Duplessy has developed a method based on fractionations that affect stable oxygen isotopes during the water cycle. This has allowed him to reconstruct the salinity of the Atlantic Ocean during the last glacial maximum with sufficient accuracy for major modelling groups to use this data to simulate global ocean circulation using general ocean circulation models. These results have provided the basis for understanding ocean circulation in glacial climates and the role that the ocean can play in disrupting climate, as outlined in a book written for the general public entitled "When the ocean gets angry ". He is also the co-author of "Gros temps sur la planète ", "Paléoclimatologie : Tome 1, and Tome 2 "Paléoclimatologie : Tome 2, Emboiter les pièces du puzzle : comprendre et modéliser un système complexe ".
Chronology plays an essential role in understanding the evolution of climates and the links with astronomical theory initiated by Dr. Milankovitch and developed by André Berger in Louvain-La-Neuve and John Imbrie at Brown University. Duplessy launched the first accelerator mass spectrometry laboratory, one of the objectives of which is the fine measurement of carbon-14 to date marine sediments. With his collaborators, he was able to provide the first evidence of a ten-degree change in seawater temperature in times compatible with human life. These results were confirmed and further refined by the study of drilling in Greenland ice. Today, rapid climatic variations are recognized as a major feature of climate change.
While developing this research and a group of marine paleoclimatology, he has endeavoured to bring to light in France the study of biogeochemical cycles within the surface envelopes of our planet. With the support of the CNRS, he launched the program to study the flow of matter in the ocean. This programme would bring together the actions of biologists, chemists and geochemists by highlighting the fundamental role of the coupling between biology and geochemistry, which led to the now recognized notion of biogeochemistry. This effort led the French teams to initiate, with their American and European colleagues, the International Joint Global Ocean Flux Study program to quantify carbon fluxes in the ocean and the role of plankton-produced particulate matter transfer in supplying the deep ocean environment with carbon, food and energy.
By the late 1980s, it had become clear that understanding living conditions on the Earth's surface required studying the couplings between the geosphere and living things. At the request of COFUSI (Comité français des unions scientifiques internationales), Duplessy chaired the French scientific committee of the International Geosphere-Biosphere Programme. He federated research on the physical, chemical and biological mechanisms that govern the evolution of our environment. This research program initiated the study of the variability of the coupled geosphere-biosphere system, giving high priority to palaeoclimatic and palaeo-environmental reconstructions over geological time. These studies have thus made it possible to highlight phenomena as unexpected as the great variability of the carbon cycle in relation to changes in vegetation. These themes will become increasingly important in the coming years in the study of human-induced climate change, as the future evolution of greenhouse gas concentrations can only be realistically simulated if the interactions between the biosphere and biogeochemical cycles are well understood, so that they can be taken into account in models simulating the behaviour of the "Earth" system. The last interglacial period of 120,000 years, often taken as an analogue of a significantly warmer climate than today, reflects major changes in global ocean temperature and circulation that have contributed to destabilizing the West Antarctic ice cap.
Honours and awards
Jean-Claude Duplessy was one of the lead authors of the "paleoclimatology" chapter of the report of the Intergovernmental Panel on Climate Change (IPCC), which was published in 2007.
His mission was to coordinate the activities of some twenty scientists from the international community with the objective of showing how the study of ancient climates makes it possible to better understand the mechanisms that could come into play in a world whose climate is disrupted by greenhouse gas and dust emissions. He was co-recipient, with his IPCC colleagues, of the 2007 Nobel Peace Prize in this capacity.
He has been a member of the French Academy of Sciences since 2011 in the "Sciences of the Universe" section.
He is a member of the European Academy of Sciences, Academia europaea since 1989
Winner of the Aimé Berthé Prize of the Academy of Sciences (1987)
Milankovitch Medal of the EGS (1995).
Winner of the Georges Lemaître Prize of the Catholic University of Louvain (1997)
Dr Honoris Causa from the University of Kiel, Germany (2003).
Grand Prix Louis D of the Institut de France 2004.
Prestwich Prize of the French Geological Society 2004.
Grand Prix Dolomieu of BRGM awarded by the Academy of Sciences in 2004.
References
1942 births
Geochemists
French climatologists
Research directors of the French National Centre for Scientific Research
École Normale Supérieure alumni
Living people | Jean-Claude Duplessy | [
"Chemistry"
] | 1,798 | [
"Geochemists"
] |
61,835,858 | https://en.wikipedia.org/wiki/Conversica | Conversica is a US-based cloud software technology company, headquartered in San Mateo, California, that provides two-way AI-driven conversational software and a suite of Intelligent Virtual Assistants for businesses to engage customers via email, chat, and SMS.
History
2007: The company was founded by Ben Brigham in Bellingham, Washington, originally as AutoFerret.com. The company's initial product was a Customer Relationship Management (CRM) targeted at automotive dealerships. This soon expanded to lead generation, and then lead validation and qualification. The AI Conversica uses currently was made to follow up on and filter out low-quality leads. The focus of the company shifted toward this automated lead engagement technology.
2010: The company started commercially selling AVA, the first Automated Virtual Assistant for sales, and the company name was changed to AVA.ai. Early customers for AVA were automotive dealerships. As the company moved away from generating leads themselves, and providing the CRM themselves, it became necessary to integrate with existing CRM and Marketing Automation platforms, such as DealerSocket, VinSolutions and Salesforce.
2013: The company raised $16m Series A funding, led by Kennet Partners, and named Mark Bradley as CEO. It also moved its headquarters from Bellingham, Washington to Foster City, California.
2014: The company changed its name from AVA.ai to Conversica.
2015: Alex Terry joined Conversica as its CEO. The business expanded to include customers in additional verticals, including technology, education, and financial services.
2016: The company raised $34m Series B funding, led by Providence Strategic Growth.
2017: Conversica expanded its intelligent automation platform and IVAs to support additional communication channels (e-mail and SMS text messaging) and communication languages. Conversica also opened a new technology center in Seattle, Washington to expand its AI and machine learning capabilities.
2018: The company raised $31m Series C funding, led by Providence Strategic Growth. Conversica also acquired Intelligens.ai, providing a regional presence in Latin America with an office in Las Condes, Santiago, Chile. The company launched an AI-powered Admissions Assistant for Higher Education industry.
2019: Conversica was selected by Fast Company magazine as one of the Top 10 Most Innovative AI Companies in the World, and was named Marketo's Technology Partner of the Year. The company officially expanded into the EMEA region with the opening of a London office. As of August 2019, Conversica has over 50 different integrations with third parties. In October Conversica won three awards at the fourth annual Global Annual Achievement Awards for Artificial Intelligence. Also that month, Alex Terry stepped down from his role as CEO and was replaced by Jim Kaskade.
2020: As part of Conversica's response to COVID-19, they optimized the business to become profitable in both 2Q20 and 3Q20, before reinvesting in 4Q20. The company transitioned both international operations in EMEA and LATAM to an indirect model with partners (LeadFabric and Nectia Cloud Solutions respectively), and moved a portion of its US-based employees to near-shore centers in Mexico and Brazil, effectively downsizing the company from 250 to 200. Conversica's reseller partner, Nectia, is a major Latin American affiliate and Chile's number one Salesforce partner, and, as part of the partnership, Nectia devoted capital to a brand new company segment, Predict-IA, dedicated to web-based artificial intelligent solutions. Predict-IA was able to immediately service all LATAM opportunities and clients with Conversica's AI Assistants with end-to-end services (marketing, sales, professional services, customer success, and technical support). Conversica's reseller partner, Leadfabric, has offices in Belgium, Amsterdam, Paris, UK, Taiwan, and Romania.
Technology
Conversica's Revenue Digital Assistants™ are AI assistants who engage with leads, prospects, customers, employees, and other persons of interest (Contacts) in a two-way human-like manner, via email, SMS text, and website chat, in English, French, German, Spanish, Portuguese, and Japanese. The RDAs are built on an Intelligent Automation platform that leverages natural language understanding, natural language processing, natural language generation, deep learning and machine learning. The Assistants are generally deployed alongside sales and marketing, customer success, account management, and higher education admissions teams, as part of an augmented workforce. The Intelligent Automation platform integrates with over 50 external systems, including CRM, Marketing Automation, and other systems of record. A partial list of integration partners includes: Salesforce, Marketo, Oracle, HubSpot, DealerSocket, Reynolds & Reynolds, CDK Global, VinSolutions and many more.
References
External links
Companies based in Bellingham, Washington
Companies based in Foster City, California
Software companies established in 2007
Deep learning
Natural language processing
Natural language generation
Software companies of the United States | Conversica | [
"Technology"
] | 1,033 | [
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61,839,702 | https://en.wikipedia.org/wiki/Samsung%20Galaxy%20M40 | The Samsung Galaxy A60 and Samsung Galaxy M40 are Android phablets manufactured by Samsung Electronics as part of its fifth-generation Galaxy A series lineup and first-generation Galaxy M series lineup. The phones feature Android 9 (Pie) with Samsung's proprietary One UI skin, 64 or 128 GB of internal storage, and a 3500 mAh battery. The A60 is marketed for China, while the M40 is marketed for India and other countries. The A60 and M40 are identical except for colors, pricing, RAM and LTE bands. The A60 was unveiled on April 17, 2019, while the M40 was unveiled on June 11, 2019.
Specifications
Hardware
The Samsung Galaxy A60 and M40 have a 6.3-inch FHD+ (1080×2340) PLS-TFT Infinity-O Display with a circular cutout for the front camera, similar to the Galaxy S10. The phones have 4 GB and 6 GB RAM versions (6 GB only for the A60), and have 64 GB or 128 GB of internal storage that is expandable to 512 GB via the microSD card slot. The phones measure 155.3 mm × 73.9 mm × 7.9 mm (6.11 in × 2.91 in × 0.31 in) and weigh 168 g, featuring a 3500 mAh battery.
The phones also have a dual-SIM slot and supports 15 W charging using Qualcomm Quick Charge 2.0 over USB-C.
Camera
The phones have a triple-lens camera consisting of a 32 MP f/1.7 wide-angle lens, 8 MP f/2.2 ultra-wide angle lens, and a 5 MP 3D depth sensor.
The triple-lens camera can create a bokeh effect through the 3D depth sensor. There is a 16 MP f/2.0 selfie camera. The camera also has Samsung's scene optimizer technology that recognizes 20 different scenes and automatically adjusts the camera.
The phones also can record 4K video through the camera application.
Software
The Samsung Galaxy A60 and M40 run on Android Pie with Samsung's One UI skin that repositions the touch area in stock Samsung apps towards the bottom, making the interface easier for one handed use with a large screen. Features include Bixby, Google Assistant, Samsung Health, and Samsung Pay, although the Bixby button is not included.
Reception
The A60 and M40 received mixed reviews. SamMobile praised the design, performance and battery life, but lamented the lack of a 3.5 mm headphone jack and the usage of an LCD panel rather than an AMOLED while criticizing the price, concluding that the M40 "is a phone that shouldn't really exist" as a higher priced alternative to the A50. It also noted that the video recording was a strong point along with the ultra-wide lens, but the cameras struggled in low-light. The software was criticized for lacking features as well. GSMArena gave both a 3.3/5, having similar complaints about the camera and display.
References
External links
(M40)
Samsung smartphones
Phablets
Samsung Galaxy
Samsung mobile phones
Android (operating system) devices
Mobile phones introduced in 2019
Mobile phones with multiple rear cameras
Discontinued Samsung Galaxy smartphones | Samsung Galaxy M40 | [
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] | 676 | [
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61,839,783 | https://en.wikipedia.org/wiki/Jennifer%20Rupp | Jennifer L. M. Rupp FRSC (born January 27, 1980) is a material scientist and professor at the Technical University of Munich, visiting professor at the Massachusetts Institute of Technology and the CTO for battery research at TUM International Energy Research. Rupp has published more than 130 papers in peer reviewed journals, co-authored 7 book chapters and holds more than 25 patents. Rupp research broadly encompasses solid state materials and cell designs for sustainable batteries, energy conversion and neuromorphic memory and computing.
Early life
Rupp was born in Germany in 1980 and grew up from her youth years in Vienna Austria. Her mother is a language teacher and her father is a physicist, the family is mixed French-German-Italian. She played competitive piano as a child and struggled to choose between pursuing her love for music and natural sciences. Rupp was active in her teen years in an environmental chemistry group and also an Austrian team member competing internationally at the International Young Physicist Team, where they won 3d place in 1998.
Education
Rupp received a Master of Natural Science Degree at the University of Vienna followed by a doctoral degree at ETH Zurich. Her undergraduate efforts were recognised by the Austrian Chemical Society, who presented her with their prize for her diploma thesis. She was awarded the ETH Zurich medal for PhD excellence for her thesis on micro-Solid Oxide Fuel Cells and functional ceramic materials under the supervision of Ludwig Gauckler at ETH Zurich.
Career
Rupp was appointed a postdoc and group leader working at ETH Zurich till 2010, where she studied solid state ionic conductors and conceptualized on micro-solid-oxide fuel cell devices. In 2011 she joined the National Institute for Materials Science in Tsukuba Japan, where she learned how to make oxide memristors for non-volatile memory concepts and protonic fuel cells. She left early as a consequence of the Fukushima Daiichi nuclear disaster and relocated in 2011 with her family to the USA where she joined as a senior scientist the Massachusetts Institute of Technology. In 2012 she was awarded a prestigious Swiss National Science Foundation professorship career grant as a non-tenure track professor at ETH Zurich intensifying her research on memristive effects and starting also on solar-to-fuel conversion materials. In 2015 she received the ERC Starting grant (backed up in this year by SNSF) as a 2nd career grant to foster more research on materials for neuromorphic computing and memories. Short after in 2017, Rupp joined as a faculty at Massachusetts Institute of Technology, where she went through the promotion from assistant to associate professor. At MIT her prime appointment was in the department of material science and engineering and she was also appointed at the electrical engineering and computer science department. In her research at MIT, she focussed intensively with her team on solid state batteries, electroceramics and the concept of Lithionics to use Li-ions beyond batteries in solids state devices to neuromorphically compute, sense or react on optical stimulation.
In fall 2021, Rupp joined as professor at Technical University of Munich keeping an appointment as visiting professor at Massachusetts Institute of Technology, as well as accepting the roles of new CTO for battery research at TUM International Energy Research. In 2023, she Co-Founded and serves as CSO of QKera GmbH, a German solid electrolyte material producer targeting inexpensive, sinter-free, low CO2 footprint solid chemistries.
Rupp serves on various advisory boards of companies with businesses on batteries or electroceramic manufacture, is an appointed Academic Director at the TUM Venture Labs to support rapid tech transfer, and is an elected Advisory Board Member of academic journals like Energy & Environmental Science, Advanced Energy Materials, Advanced Functional Materials and others. Since 2017, she is a multiple-times reelected Associate Editor at the Journal of Materials Chemistry A.
In 2019, she founded the LILA Mentorship program for Minorities in Engineering and Sciences in an effort to bridge the ever-existing gender gap, support minority groups and foster diversity in future leadership in energy and solid-state chemistry/material R&D.
Battery research
Rupp is developing next-generation batteries for application in electric vehicles and portable electronics, focusing on novel material synthesis and cell designs. Her research contributes to safer Li-conducting solid-electrolyte alternatives to classic polymers for lithium-ion solid and hybrid batteries by pioneering innovative solid-state synthesis chemistries like the sequential deposition synthesis in collaboration with Samsung, effects and structure science. She has also made major contributions in developing battery ceramic synthesis routes for thin electrolyte compounds, contribute to interface engineering electrode-electrode designs and structural design of various electrolyte and electrode chemistries. She talks about battery research in the Battery generation Podcast, which reaches ++105000 times watches in short time.
Lithionic research
In her Lithionic research, she has developed one of the key papers discussing structure-property requirements of Li-based solid state materials to execute Lithionic functions to neuromorphically compute, sense or react on optical stimuli beyond battery applications. The work lead to a larger research consortium funded by Ericsson to foster the tech for 6G at MIT and was initiated and led by Rupp. In the quest of having less materials serving more functions for future devices she contributes with material concepts, chemistry and physical operations to execute additional functions beyond classic energy storage.
Solid state ionics and electronics research & device engineering
The theme of solid state ionics and electronics is deeply centered in Rupp's work. Her objectives are to create tailored solid state materials and electroceramics for energy conversion and storage or information computing. This includes material design and fundamental model experiments on electro-chemo-mechanics for ionic conductors (i.e. with strain modulus) or also recent work with her colleague Harry Tuller (MIT) and students on opto-ionics. Applications of fast ion conductors include fuel cells, sensors, batteries, memristors, or neuromorphic computing chips. Several proof-of-concept devices and electrochemical operation principles stem from Rupp's team such as strained memristors, or recently proposed glucose-converting fuel cell chips for human implants.
Industrial collaboration, support and consultancy
Rupp has collaborated, served as a consultant to or received competitive awards from several companies including BMW, Samsung, Ericsson, Shell, Equinor, Alkegen, Unifrax, SiFab, Sensirion, Eni, Merck, BASF, Volkswagen,Oerlikon and NGK/NTK.
Awards and honors
2024-2029 Max Planck Fellow
2024 Vice President of the International Society for Solid State Ionics (ISSI)
2024 Member of National Academy of Sciences Leopoldina
2024 American Ceramic Society's Richard M. Fulrath Award for excellence in research and development of ceramic sciences and materials
2021 Fellow of the Royal Chemical Society for outstanding achievements in chemical sciences (FRSC title)
2021 Samsung Recognition for Important Battery Advancements
2021 Nature Sustainability Expert Panel Leader for Batteries
2018 Merck Displaying Futures Award for energy implant device
2017 BASF and Volkswagen Science Award Electrochemistry for battery research
2018-2016 World Economic Forum council member on future of computing
2015 ERC Starting Grant
2015 World Economic Forum Top 40 international scientist under the age of 40
2014 Spark Award
2012 Swiss National Science Foundation SNSF Professorship Grant, Switzerland (2012)
2012 European Academy of Sciences Kepler Prize "Materials for Energy Technology"
2005 Young Scientist Award, International Solid State Ionics Society
See also
Lithionics
References
Women materials scientists and engineers
MIT School of Engineering faculty
ETH Zurich alumni
1980 births
Living people
Austrian expatriates in the United States
American materials scientists
Solid state chemists
University of Vienna alumni
Austrian women chemists
21st-century scientists
21st-century Austrian women scientists
21st-century Austrian scientists
Austrian chemists
21st-century chemists
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61,840,134 | https://en.wikipedia.org/wiki/Recam%C3%A1n%27s%20sequence | In mathematics and computer science, Recamán's sequence is a well known sequence defined by a recurrence relation. Because its elements are related to the previous elements in a straightforward way, they are often defined using recursion.
It takes its name after its inventor , a Colombian mathematician.
Definition
Recamán's sequence is defined as:
The first terms of the sequence are:
0, 1, 3, 6, 2, 7, 13, 20, 12, 21, 11, 22, 10, 23, 9, 24, 8, 25, 43, 62, 42, 63, 41, 18, 42, 17, 43, 16, 44, 15, 45, 14, 46, 79, 113, 78, 114, 77, 39, 78, 38, 79, 37, 80, 36, 81, 35, 82, 34, 83, 33, 84, 32, 85, 31, 86, 30, 87, 29, 88, 28, 89, 27, 90, 26, 91, 157, 224, 156, 225, 155, ...
On-line encyclopedia of integer sequences (OEIS)
Recamán's sequence was named after its inventor, Colombian mathematician Bernardo Recamán Santos, by Neil Sloane, creator of the On-Line Encyclopedia of Integer Sequences (OEIS). The OEIS entry for this sequence is .
Visual representation
The most-common visualization of the Recamán's sequence is simply plotting its values, such as the figure at right.
On January 14, 2018, the Numberphile YouTube channel published a video titled The Slightly Spooky Recamán Sequence, showing a visualization using alternating semi-circles, as it is shown in the figure at top of this page.
Sound representation
Values of the sequence can be associated with musical notes, in such that case the running of the sequence can be associated with an execution of a musical tune.
Properties
The sequence satisfies:
This is not a permutation of the integers: the first repeated term is . Another one is .
Conjecture
Neil Sloane has conjectured that every number eventually appears, but it has not been proved. Even though 10230 terms have been calculated (in 2018), the number 852,655 has not appeared on the list.
Uses
Besides its mathematical and aesthetic properties, Recamán's sequence can be used to secure 2D images by steganography.
Alternate sequence
The sequence is the most-known sequence invented by Recamán. There is another sequence, less known, defined as:
This OEIS entry is .
References
External links
The Recamán's sequence at Rosetta Code
The Ultimate Guide to Recamán’s Sequence (visualization, sonification, and animation)
Sequences and series
Integer sequences
Recurrence relations | Recamán's sequence | [
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61,843,024 | https://en.wikipedia.org/wiki/Glowmatography | Glowmatography is a laboratory technique for the separation of dyes present in solutions contained in glow sticks. The chemical components of such solutions can be chromatographically separated into polar and nonpolar components. Developed as a laboratory class experiment, it can be used to demonstrate chemistry concepts of polarity, chemical kinetics, and chemiluminescence.
Description
In the chromatography of a glow stick solution, a piece of chalk, a highly polar substance, is used as the stationary phase while comparatively less-polar solvents like acetone and 91% isopropyl alcohol can be used as the mobile phase. Chalk is made up of calcium carbonate (CaCO3) or calcium sulfate (CaSO4), and therefore contains ions. This allows it to attract other ions and polar molecules, but not nonpolar molecules. As a result, ionic and more-polar dyes would be attracted to the stationary phase and move relatively slowly or a fairly small distance, while less polar dyes would migrate further as the mobile phase wicks up the chalk. This then allows for the separation of dyes.
Experiment
This experiment can be conducted with glow sticks, chalks, and solutions of acetone or isopropyl alcohol.
Drops of glowing fluid from a glow stick are added to a chalk so that a band is created halfway through it. The chalk is then placed vertically into a beaker filled with a small amount of acetone or alcohol - ensuring the surface of the solvent is below the dye band. The liquid is then allowed to travel up the chalk; polar dyes would tend to stick to the chalk and not travel significantly while non-polar dyes would travel up with the solvent. Once it travels almost to the top of the chalk, it is removed from the beaker. The chalk chromatogram, with separation of colours, can then be observed in a dark room.
Additionally, this glomatographic experiment can be done using other materials. For instance, silica gel can be used as the stationary phase together with a solution of nonpolar hexanes acting as the mobile phase. The polar components would be attracted to the polar silanol (Si-OH) groups on the surface of the silica gel, and the nonpolar components would travel further with the hexanes. Further, dyes in glow sticks can also be extracted using liquid carbon dioxide (CO2) as an environmentally friendly or green solvent. In this case, non polar dyes would dissolve in the liquid CO2 and other dyes would be attracted to cotton.
See also
Retardation factor
References
External links
Chemistry classroom experiments
Chromatography | Glowmatography | [
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] | 544 | [
"Chromatography",
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41,363,717 | https://en.wikipedia.org/wiki/EuroFlow | EuroFlow consortium was founded in 2005 as 2U-FP6 funded project and launched in spring 2006. At first, EuroFlow was composed of 18 diagnostic research groups and two SMEs (small/medium enterprises) from eight different European countries with complementary knowledge and skills in the field of flow cytometry and immunophenotyping. During 2012 both SMEs left the project so it obtained full scientific independence. The goal of EuroFlow consortium is to innovate and standardize flow cytometry leading to global improvement and progress in diagnostics of haematological malignancies and individualisation of treatment.
Background
Since the '90s immunophenotyping (staining cells with antibodies conjugated with fluorochromes and detection with flow cytometer) became the preferred method in diagnostics of haematological malignancies. The advantages of this method are speed and simplicity, possibility to measure more than 6 parameters at a time, precise focusing on malignant population and also broad applicability in diagnostics. Because there is a great progress in development of antibodies, fluorochromes and multicolor digital flow cytometers, it became a question of how to interpret cytometric data and how to achieve comparable results between facilities. Even though a consensus of recommendations and guidelines was established, standardization was only partial because there was no regard of different antibody clones, fluorochromes and their optimal combinations or of sample preparation. On that account cytometry is perceived as method highly dependent on level of expertise and with limited reproducibility in multicentric studies.
Goals of Euroflow
These goals were set out in the journal Leukemia in 2012.
Development and evaluation of new antibodies
Establishment of new immunobead assay technology
Development of new software tools followed by new analysing approaches for recognition of complex immunofenotype patterns.
Design of new multicolor protocols and standard operating procedures (SOPs)
Development and standardization of fast, accurate and highly sensitive flow cytometry
Achievements
During passed few years EuroFlow achieved most of its goals. Eight-color panels for diagnoses, and classification and follow-up of haematological malignancies were established. Panels, consisting of screening tube and supplementary characterisation tubes, are based on experiences and knowledge from literature but further optimised and tested in multiple research centers on large collection of samples impeaching on selection of fluorochromes and standardization of instrument settings and SOPs. Antibody clones, fluorochromes and other reagencies from different companies underwent detailed testing and comparison. Simultaneously a new software for analysing of more complex and extensive data files was developed, capable of multidimensional statistical comparison of normal data samples and patient samples. Also new antibody clones against rigorously selected epitopes of proteins involved in chromosomal translocations were developed for detection of most frequent fusion proteins in acute leukemia and chronic myeloid leukemia. Also detection of fusion proteins using immunobead assays was introduced.
References
External links
EuroFlow
Flow cytometry | EuroFlow | [
"Chemistry",
"Biology"
] | 631 | [
"Flow cytometry"
] |
41,365,100 | https://en.wikipedia.org/wiki/List%20of%20largest%20plants | This is a list of the largest plants by clade. Measurements are based on height, volume, length, diameter, and weight, depending on the most appropriate way(s) of measurement for the clade.
Gymnosperms (Gymnospermae)
Conifers (Pinopsida)
The conifer division of plants includes the tallest organism, and the largest single-stemmed plants by wood volume, wood mass, and main stem circumference. The largest by wood volume and mass is the giant sequoia (Sequoiadendron giganteum), native to Sierra Nevada and California; it grows to an average height of and in diameter. Specimens have been recorded up to in height and (not the same individual) in diameter; the largest individual still standing is the General Sherman tree, with a volume of .
Although typically not so large in volume, the closely related coast redwood (Sequoia sempervirens) of the Pacific coast in North America is taller, reaching a maximum height of – the Hyperion Tree, which ranks it as the world's tallest known living tree and organism (not including its roots underground). The largest historical specimen (and largest known single-stem organism) was the Lindsay Creek Tree, a coast redwood with a minimum trunk volume of over and a mass of over . It fell during a storm in 1905.
The conifers also include the largest tree by circumference in the world, the Montezuma cypress (Taxodium mucronatum). The thickest recorded tree, found in Mexico, is called Árbol del Tule, with a circumference of at its base and a diameter of at above ground level; its height is over . These trees dwarf any other non-communal organism, as even the largest blue whales are likely to weigh one-sixteenth as much as a large giant sequoia or coast redwood. See list of superlative trees for other tree records.
Cycads (Cycadophyta)
The largest single-stemmed species of cycad is Hope's cycad (Lepidozamia hopei), endemic to the Australian state of Queensland. The largest examples of this species have been over tall and have had a circumference of .
However the multi-stemmed Encephalartos laurentianus (Zamiaceae) of Bandundu Province in Congo (Kinshasa) and in adjoining parts of Angola is much more massive. The stems, which can be upright when young, but sprawling when mature, are up to in length, and up to in diameter. Assuming a density of 1.0, an old much-branched specimen could weigh up to 45 tonnes (50 short tons).
Flowering plants (Angiospermae)
This is the most diverse and numerous division of plants, with upwards of 400,000 species.
Clonal colonies
For two-dimensional area, the largest known clonal flowering plant, and indeed largest plant and organism, is a grove of male Aspen in Utah, nicknamed Pando (Populus tremuloides). The grove is connected by a single root system, and each stem above the ground is genetically identical. It is estimated to weigh approximately , and covers .
A form of flowering plant that far exceeds Pando as the largest organism on earth in breadth, is the giant marine plant, Posidonia australis, living in Shark Bay, Australia. Its length is about and it covers an area of . It is estimated to be over 4,500 years old. Believed to have sprouted from a single seed, it grows at about the same rate as a lawn, up to a year.
Another form of flowering plant Posidonia oceanica discovered in the Mediterranean may be the oldest living organism in the world, with an estimated age of 100,000 years.
"Individual" plants
By a stricter definition of individuality, and using contending measures of size, Ficus benghalensis, the giant banyan trees of India are the largest trees in the world. In these trees, a network of interconnected stems and branches has grown entirely by vegetative, "branching" propagation. One individual, Thimmamma Marrimanu, in Andhra Pradesh, covers 19,107 square metres, making it the largest single tree by two-dimensional canopy coverage area. This tree is also the world's largest known tree by a related measure, perimeter length, with a distance of 846 metres required to walk around the edge of the canopy. Thimmama Marrimanu is likely also the world's largest tree by three-dimensional canopy volume.
The tallest flowering plant species known is Eucalyptus regnans, of which a living specimen has been measured at in Southern Tasmania. The longest vine to be accurately measured is "Rattan Manau" (Calamus manan) of the palm family (historically Palmae, but now often Arecaceae) and native to the Malay Peninsula, Sumatra and Java. One unbranched stem at Buitenzorg (now Bogor) Botanic Garden, Java was carefully measured to a length of .
Of herbaceous plants, plants without persistent woody growth above ground, Musa ingens is the largest. It can reach about 15 meters tall with a pseudostem diameter of around a meter. It also holds the record for the longest petioles or leaf stalks of any plant.
Bamboos are a subfamily (Bambusoideae) of flowering perennial plants in the grass family Poaceae, comprising three tribes: Arundinarieae, Bambuseae, and Olyreae. Dendrocalamus is a tropical genus of giant clumping bamboo found throughout Southeast Asia. It includes Dendrocalamus giganteus, which can reach heights up to 30 m.
Other records among flowering plants include, the title of largest flower, which belongs to the species Rafflesia arnoldii. One of these flowers can reach a diameter of and weigh up to . The largest unbranched inflorescence, resembling (but not qualifying as) a giant flower, belongs to the titan arum (Amorphophallus titanum), reaching almost in height. The absolute largest inflorescence, at up to long, is borne by the talipot palm (Corypha umbraculifera) of India. The largest leaves belong to either Gunnera manicata, Raphia regalis, Manicaria saccifera, Marojejya darianii, Johannesteijsmannia altifrons, or Victoria boliviana, depending on criteria.
Pteridophyta
Horsetails (Equisetopsida)
The largest of horsetail is the species Equisetum myriochaetum, native to Nicaragua, Costa Rica, Colombia, Venezuela, Ecuador, Peru and Mexico. The biggest specimen known was tall and had a diameter of .
Ferns (Pteridopsida)
The largest species of fern is probably Cyathea brownii of Norfolk Island, which may be or more in height.
Bryophytes
Liverworts (Marchantiophyta)
The largest species of liverwort is a New Zealand species, Schistochila appendiculata. The top size of this species is long, a diameter of and a stem length of . Another New Zealand liĬverwort, Plagiochila gigantea (Jungermaniaceae) is a cushion plant up to three feet (91 centimeters) in width and up to 2.5 feet (75 centimeters) in height. It is endemic to the Southern Alps of South Island.
Mosses (Bryophyta)
The world's most massive moss is Dawsonia superba, of Australia and New Zealand. This species has numerous tall, upright shoots, joined by a network of rhizomes. The tallest moss is Spiridens reinwardtii of the family Hypnodendraceae and native to Indonesia, Malaysia, Papua New Guinea, the Philippines, Melanesia and Taiwan. S. reinwardtii is a vine which is typically high but can climb to a height of . Spiridens reinwardtii is the only true vine among mosses and climbs by twining. The longest individuals seem to be in New Guinea.
See also
Largest organisms
List of superlative trees
List of world records held by plants
List of largest inflorescences
List of world's largest seeds
List of world's largest mushrooms and conks
List of world's longest vines
References
Organism size
Largest
Plant | List of largest plants | [
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41,365,652 | https://en.wikipedia.org/wiki/List%20of%20largest%20fish | Fish vary greatly in size. The whale shark and basking shark exceed all other fish by a considerable margin in weight and length. Fish are a paraphyletic group that describes aquatic vertebrates while excluding tetrapods, and the bony fish that often represent the group are more closely related to cetaceans such as whales, than to the cartilaginous fish such as sharks and rays. As such, cross group comparisons on this page only serve a colloquial purpose.
Largest extant fish
Jawless fish (Agnatha)
Hagfish (Myxini)
The hagfish, which are not taxonomically true fish, are among the most primitive extant vertebrates. There is only one order and family in this animal class. All of the 77 known species have elongated, eel-like bodies but can be distinguished by their downward-facing mouths. The largest form is the Goliath hagfish (Eptatretus goliath). This species can range up to in length and weigh to .
Lampreys (Petromyzontiformes)
As with the hagfish, lampreys appear eel-like in shape. They have cartilaginous skeletons and have been evolving separately from any other group for over 400 million years. They are predatory and often attach themselves to a fish or other small animal and gradually drain blood and organs. The largest species is the sea lamprey (Petromyzon marinus), which can grow to and weigh .
Armored fish (Placodermi)
The largest fish of the now-extinct class Placodermi was the giant predatory Dunkleosteus. The largest and most well known species was D. terrelli, which grew almost in length and in weight. Its filter feeding relative, Titanichthys, may have rivaled it in size. Titanichthys reached a length of though in older paper it was estimated at .
Cartilaginous fish (Chondrichthyes)
The cartilaginous fish are not directly related to the "bony fish," but are sometimes lumped together for simplicity in description. The largest living cartilaginous fish, of the order Orectolobiformes, is the whale shark (Rhincodon typus), of the world's tropical oceans. It is also the largest living animal that is not a cetacean and, like the largest whales, it is a docile creature that filter-feeds on tiny plankton. An average adult of this species measures long and weighs an average of 9 tonnes. The largest verified specimen was caught in 1949 off Karachi, Pakistan and was long and weighed . Although many are dubious, there are several reports of larger whale sharks, with reliable sources citing unverified specimens of up to and .
Ground sharks (Carcharhiniformes)
The largest species of this order is the widely distributed tiger shark (Galeocerdo cuvier). Specimens have been verified to at least but even larger ones have been reported. One specimen, a gravid female caught off Australia and measuring only long, weighed an exceptional . A female caught in 1957 reportedly measured and weighing , although this very outsized shark is not known to have been confirmed. The largest of the "requiem sharks" (in the genus Carcharhinus) seems to be the dusky shark (C. obscurus), at up to and a weight of . However, the bulkier bull shark (C. leucas) has been estimated to weigh about in recent specimens that measured over long. The silky shark (C. falciformis) is another contender for the largest requiem shark at a maximum weight of and a maximum length of around . The largest hammerhead shark is the great hammerhead (Sphyrna mokarran), which can reach and weigh at least . The most species-rich shark family, the catsharks, are fairly small-bodied. The largest, the nursehound (Scyliorhinus stellaris), can grow up to and a weight of at least .
Chimaeras (Chimaeriformes)
These odd, often translucent cartilaginous fish are typically quite small. The largest species is the carpenter's chimaera (Chimaera lignaria) of the oceans near Australia and New Zealand. It can reach up to in length and weigh .
Frill sharks and cow sharks (Hexanchiformes)
The largest frill sharks and cow shark is the Bluntnose sixgill shark (Hexanchus griseus). This large species typically inhabits depths greater than , and has been recorded as deep as . The largest specimen known (caught off Cuba) reportedly weighed and measured long.
Bullhead sharks (Heterodontiformes)
These tropical, small sharks are noted for their broad head shape. The largest species is the Port Jackson shark (Heterodontus portusjacksoni) of Australasian waters, at up to long and weighing up to .
Mackerel sharks (Lamniformes)
Most species in this order grow quite large. The largest living species is the basking shark (Cetorhinus maximus) of the world's northern temperate oceans, also the second largest fish. The largest specimen, which was examined in 1851, measured long and weighed 16 tonnes. Perhaps the most famous "big fish" is the great white shark (Carcharodon carcharias). Specimens have been measured up to and weighing , with great whites of at least long generally accepted. The common thresher (Alopias vulpinus), can grow to and weigh over , but much of its length is comprised by its extreme tail. Odd and recently discovered giants also live in this order: the slender, sword-snouted goblin shark (Mitsukurina owstoni), with unweighed specimens of up to approximately , and the massive megamouth shark (Megachasma pelagios), up to long and a weight of .
The largest shark in the fossil record is the megalodon (Otodus megalodon), a colossal Neogene lamniform. The range of estimates of the maximum length for megalodon are from , with a mass ranging from . It is also regarded as the largest macro-predatory fish ever.
Stingrays and allies (Myliobatiformes)
Both the largest species of this order and the largest of all rays is the giant oceanic manta ray (Manta birostris). This peaceful leviathan can reach a size of , a "disk" width of and a total length of . A related species reaches barely smaller sizes, the devil fish (Mobula mobular). It can grow up to a disk width, a total length of and a weight of at least . The largest stingray is generally accepted to be the short-tail stingray (Dasyatis brevicaudata), found off the southern tip of Africa and Australasia, at up to across the disk and weighing more than . Although there are several large stingrays that at least approach this species' size. One, the giant freshwater stingray (Himantura polylepis), of the large rivers of South Asia, can weigh up to , measure up to in total length and have a disc span of .
Carpet sharks (Orectolobiformes)
The whale shark is the largest species in this order, reaching up to 20 meters long when fully mature. No other species in the order even approaches this size. The next largest species is the nurse shark (Ginglymostoma cirratum), which can grow up to across the disk and weighing more than .
Sawfish (Pristiformes)
Distinguished by a long snout decorated with sharp teeth on the sides, these little-known cartilaginous fish are often reported to attain huge sizes. The definitive largest species is not known, although the smalltooth sawfish (Pristis pectinata) and the green sawfish (P. zijsron), at up to reportedly , respectively, may be the largest. Weights of up to have been reported, possibly for the smalltooth species, but are not verified. The large-tooth sawfish (P. pristis) and freshwater sawfish (P. microdon) can both exceed .
Sawsharks (Pristiophoriformes)
Despite sharing a similar appearing snout adapted in both to shred fish prey, the sawsharks are typically much smaller than sawfish. The largest sawshark is the Sixgill sawshark (Pliotrema warreni) of the South Indian ocean, which can grow up to and weigh .
Skates and allies (Rajiformes)
The largest and most diverse order of rays' largest species is the giant guitarfish (Rhynchobatus djiddensis) of the Red Sea and the eastern Indian ocean. The top size of the species is and . The largest of the skates is the common skate (Dipturus batis). This species can grow up to in length and weigh .
Dogfish and allies (Squaliformes)
The largest known member of this order is the Greenland shark (Somniosus microcephalus), a giant predator of sub-Arctic waters. This species has been confirmed to as much as in length and a weight of , although specimens of up to have been reportedly caught. The Pacific sleeper shark (Somniosus pacificus) has been measured only to and in a gravid female, although specimens up to an estimated have been scientifically observed. A single unconfirmed account exists of an enormous Pacific sleeper shark that potentially measured up to long. The spiny dogfish (Squalus acanthias), a very common species, reaches the largest sizes of the "true dogfish" family. Specimens have been measured at up to and .
Angelsharks (Squatiniformes)
The largest of the bottom-dwelling angelsharks (named for their shape rather than disposition) is the common angelshark (Squatina squatina) of the northeast Atlantic Ocean. This species can grow up to long and weigh up to .
Electric rays (Torpediniformes)
The largest of the electric rays is Atlantic torpedo (Torpedo nobiliana). This fish can measure long and weigh . However, a length of and weight of is more typical. Females attain a larger size than males.
Spiny sharks (Acanthodii)
The largest of the now-extinct Acanthodii was Xylacanthus grandis, an ischnacanthiform based on a ~ long jaw bone. Based on the proportions of its relative Ischnacanthus, X. grandis had an estimated total length of .
Bony fish (Osteichthyes)
Ray-finned fish (Actinopterygii)
The largest living bony fish (superclass Osteichthyes, which includes both ray-finned and lobe-finned fish) are the lesser known southern sunfish (Mola alexandrini) followed by widely distributed and better known ocean sunfish (Mola mola) and, both being members of the order Tetraodontiformes. The largest verified specimen belongs to the southern sunfish discovered dead near the Azores in the Atlantic has set the record for being the largest extant bony fish with the weight of . The record size ocean sunfish crashed into a boat off Bird Island, Australia in 1910 and measured from fin-to-fin, in length and weighed about , while the other record for the biggest bony fish is yet held by a Mola alexandrini which was also coincidentally in mass and in length, caught off in 1996 and misidentified as a Mola mola.
As for length, the longest extant bony fish on earth is the giant oarfish (Regalecus glesne). Slender and compressed, it averages over long at maturity. A specimen caught in 1885 of in length weighed . The longest known example, which was hit by a steamship, was measured as long.
Much larger bony fish existed prehistorically, the largest ever known having been Leedsichthys of the Jurassic period. This species is certainly the largest bony fish ever and perhaps the largest non-cetacean marine animal to have ever existed. Estimates of the size of this fish range from and mass from 20 to 50 tons. A maximum size of and 25–30 tons has been deemed to be most realistic.
Sturgeons and paddlefishes (Acipenseriformes)
The largest species is the beluga sturgeon (Huso huso) of the Caspian and Black seas, the only extant bony fish to rival the massiveness of the ocean sunfish. The largest specimen considered reliable (based on remains) was caught in the Volga estuary in 1827 and measured and weighed . The slightly smaller kaluga (Huso dauricus) or great Siberian sturgeon has been weighed reliably up to (Berg, 1932) and a length of . The North American white sturgeon (Acipenser transmontanus), unverified to and , Chinese, European oceanic, and the Russian sturgeon (A. gueldenstaedtii), at as much as and for a 75-year-old female, also can attain great sizes. Atlantics and Baikal sturgeons are following as well. These fish are sometimes called the largest freshwater fish but sturgeons spend a great deal of time in brackish water and switch back and forth between saltwater and freshwater environments in their life cycle. Also included in this order are the paddlefish and the Chinese paddlefish (Psephurus gladius), which is now officially recognised as extinct by the IUCN (as of July 2022), is also a very large fish. Reportedly, fisherman as recently as the 1950s have caught paddlefish measuring up to in total length, although no specimen greater than has been scientifically measured. The weight of the Chinese paddlefish is reportedly .
Bonefish (Albuliformes)
The largest Albuliformes is the bonefish (Albula vulpes), which weighs up to and measures up to long. It is silvery in color with dusky fins. The bases of the pectoral fins are yellow.
Bowfins (Amiiformes)
The bowfin (Amia calva) is the sole extant member of its order. The most distinctive characteristic of the bowfin is its very long dorsal fin consisting of 145 to 250 rays, and running from mid-back to the base of the tail. The caudal fin is a single lobe, though heterocercal. They can grow up to in length, and weigh .
Eels (Anguilliformes)
The largest species of "true eel," if measured in weight and overall bulk, is the European conger (Conger conger). The maximum size of this species has been reported to and a mass of . Several moray eels can equal or exceed the previous eel in length but do not weigh as much. The longest fish in the order, at up to , is the slender giant moray (Strophidon sathete) of the Indo-Pacific oceans.
Silversides (Atheriniformes)
An order best known for its tiny representatives, the largest species is the jacksmelt (Atherinopsis californiensis) of the Pacific Ocean. Although it reaches , it is not known to even reach .
Barreleyes, slickheads and argentines (Argentiniformes)
The largest species is the greater argentine (Argentina silus), that has TL.
The largest barreleyes are javelin spookfish (Bathylychnops exilis) found in the northern Pacific and in the eastern Atlantic Ocean near the Azores where it is found at depths of around . This species grows to a length of SL.
Jellynose fishes (Ateleopodiformes)
Jellynose fish are benthic marine fish typically found at depths around . Size ranges from (Ateleopus japonicus) to 2 meters (Guentherus altivela).
Grinners (Aulopiformes)
The largest member of this order is the lancetfish (Alepisaurus ferox), found in all the world's oceans. Slender, with a huge spine, these fish can reach long and can weigh up to .
Toadfish (Batrachoidiformes)
The largest toadfish is the Pacuma toadfish (Batrachoides surinamensis), reaching a size of up to and .
Flying-fish and allies (Beloniformes)
The largest member of this order, best known for its members' ability to breach the water and glide through the sky, is the pelagic Houndfish (Tylosurus crocodilus), a slender fish at up to and a weight of . The largest true "flying fish" is the Japanese flying fish (Cheilopogon pinnatibarbatus japonicus), which can range up to in length and weigh over .
Squirrelfish (Beryciformes)
Best known for their highly poisonous barbs, the squirrelfish's largest representative is the giant squirrelfish (Sargocentron spiniferum) of the Indo-Pacific, at up to and . The slimmer Holocentrus adscensionis from warm parts of the Atlantic can reach even greater lengths of up to .
Whalefish (Cetomimiformes)
Known for flesh that feels flabby to the touch, this order reaches largest sizes in the flabby whalefish (Gyrinomimus grahami) of all southern oceans. This species, which can range up to in length and weigh , is sometimes commercially fished.
Characins (Characiformes)
The largest species is the African freshwater fish, the giant tigerfish (Hydrocynus goliath). The top size of this fish is and . Among the largest of the characin family is the popular sport-fish, the golden dorado (Salminus brasiliensis), which can reach up to in length and weigh . Among the characins are the infamous neotropical piranhas. Carnivorous species can grow up to , although the Tambaqui (Colossoma macropomum), at up to and , is often considered a giant, herbivorous form of piranha.
Herring (Clupeiformes)
The largest herring is probably the Dorab wolf herring (Chirocentrus dorab) of the Indo-Pacific oceans. The maximum size of this species has been reported as much as , but these slender fish have never been recorded as exceeding in weight. The so-called "king of herrings" is not a herring, but an oarfish.
Minnows and allies (Cypriniformes)
The minnow family (which includes carp), Cyprinidae, is the largest family of vertebrates, with over 2400 species known today. The largest species is the giant barb (Catlocarpio siamensis), which is endemic to three river basins in southeast Asia and reaches a size of as much as and a weight of as much as . In centuries past, mahseer, specifically the golden mahseer (Tor putitora) of Southern Asia was reported to reach similar lengths, but the species has been overfished and specimens nearly as large as the giant barb have not been reported in recent centuries.
Pikes and allies (Esociformes)
The largest species in this small but interesting order (formerly allied with the salmonids) is the muskellunge (Esox masquinongy) of the rivers of North America. These predatory fish can grow up to and .
Killifish and allies (Cyprinodontiformes)
The largest species in this relatively small-bodied order is the Pacific four-eyed fish (Anableps dowei), reaching a size of and .
Ladyfish and allies (Elopiformes)
This small order is usually considered closely related to the true eels although its members are very different in appearance and behavior from eels. The largest species is much-coveted-sport fish, the Atlantic tarpon (Megalops atlanticus). The maximum recorded size for this species is and length is up to .
Cod (Gadiformes)
The Atlantic cod (Gadus morhua) grows to long and .
Sticklebacks and allies (Gasterosteiformes)
The largest form of stickleback, a small, cylindric type of fish, is the sea stickleback or fifteenspine stickleback (Spinachia spinachia). This species can range up to in length and weigh up to .
Clingfish (Gobiesociformes)
These bottom-dwelling fish reach their maximum size in Sicyases sanguineus. This species can reach in length and weigh up to .
Shellears and allies (Gonorynchiformes)
The well-known milkfish (Chanos chanos) is the largest member of this order. The maximum size is and long.
Knifefish (Gymnotiformes)
The largest knifefish is the electric eel (Electrophorus electricus) The electric eel has an elongated, cylindrical body, typically growing to about in length, and in weight, making it the largest species of the Gymnotiformes.
Mooneyes (Hiodontiformes)
Only two extant species are known to exist in this relatively new order. The larger of the two is the goldeye (Hiodon alosoides) from the northern rivers of North America, which can reach up to in length and can weigh .
Ribbonfish and allies (Lampriformes)
The largest member of this small but fascinating order is the aforementioned king of herrings or oarfish (Regalecus glesne), the longest extant bony fish on earth. Another interesting big fish in this order is the opah (Lampris guttatus), which as opposed to the king of herrings, is massive and has a chunky, rounded shape. Opahs can range up to in length and weigh up to .
Gars (Lepisosteiformes)
The largest of the gar, and the largest entirely freshwater fish in North America, is the alligator gar (Atractosteus spatula). The largest gar ever known, caught in Louisiana in 1925, was in length and weighed .
Anglerfish (Lophiiformes)
The largest of this diverse order is the common goosefish (Lophius piscatorius) found in the northeastern Atlantic off Europe and North Africa. This big-mouthed fish can attain a size of and a length of .
Lanternfish (Myctophiformes)
The largest of the numerous but small lanternfish is Bolin's lanternfish (Gymnoscopelus bolini) of the Indo-Pacific oceans, at up to and .
Mullets (Mugiliformes)
The largest of mullets flathead mullet (Mugil cephalus) have dark centers which give the appearance of a series (6–7) of dark horizontal stripes. The fish grow to lengths up to with weights as high as .
Pearlfish and allies (Ophidiiformes)
The largest member of this order is the widely distributed giant cusk-eels (Lamprogrammus shcherbachevi). A cuskeel can be nearly long, but even large fish probably aren't much over since they are quite slender.
Smelts and allies (Osmeriformes)
The largest smelt is the rainbow smelt (Osmerus mordax). The body of the rainbow smelt is slender and cylindrical. When full grown, the rainbow smelt is between long and weighs about . Individuals over long are known.
Bony-tongued fish (Osteoglossiformes)
The largest species is the South American fish usually known as the arapaima (Arapaima gigas). The maximum size this species can attain is a matter of some controversy and some rank it among the world's largest freshwater fishes. No individual arapaima over has been verified and measured. The skeleton of a fish reported to have been measured by native hunters as and weighing when caught, was later examined as a skeleton scientifically and was found to have been roughly within that outsized dimension.
Perches and allies (Perciformes)
The title of the largest member of this order, the most numerous order of all vertebrates, is a matter of some debate. A large marlin is the biggest of these fishes: the black marlin (Makaira indica) of the Indo-Pacific, the Atlantic blue marlin (Makaira nigricans) and the Indo-Pacific blue marlin (Makaira mazara). All of these similarly sized species can exceptionally reach up to in length and weight may be as much as or even . Another notable giant of the perch order is the Atlantic bluefin tuna (Thunnus thynnus) of the Northern Atlantic ocean, which has been verified at up to and , although can reportedly reach . The swordfish (Xiphias gladius) can reach a maximum weight of and length of . Due to heavy fishing of both species, swordfish and tuna of great sizes are increasingly rare. One of the largest freshwater fishes is the Nile perch (Lates niloticus), which grows up to and . The biggest of snappers is the Cubera snapper (Lutjanus cyanopterus) of the Caribbean sea and east coast of South America, at a maximum size of and in length. The largest species of grunt is the white margate (Haemulon album) of the Caribbean sea and east coast of South America, at up to and in length. The blennies can range up to in the hairtail blenny (Xiphasia setifer) of the Indo-Pacific. The jacks or mackerels reach their maximum size in the Chinese seerfish (Scomberomorus sinensis), which can attain and . The largest butterflyfish are either the lined butterflyfish (Chaetodon lineolatus) or the saddle butterflyfish (C. ephippium), both of the Indo-Pacific and both of which can measure up to . The freckled darter (Percina lenticula) of the United States, the biggest of the darters, reaching and . The largest drum is the Totoaba (Totoaba macdonaldi) of the Gulf of California, at up to and long. Among the sea bass or groupers, many of which can grow quite large, the greatest size are reached in the Atlantic goliath grouper (Epinephelus itajara) and the giant grouper (Epinephelus lanceolatus). Both can reach a maximum known length of and weight of and respectively. The species-rich cichlids reach their maximum size in the East African giant cichlid (Boulengerochromis microlepis), at up to long and . The humphead wrasse (Cheilinus undulatus) of the Indo-Pacific's coral reefs is by far the largest wrasse, and it can reach a maximum size of and . Among a fairly small-bodied family, the damselfishes, the Garibaldi (Hypsypops rubicundus) of the Pacific coast of America is the biggest, reaching up to and . The marbled sleeper (Oxyeleotris marmorata) of East Asia is the largest member of the family or sub-order that almost certain contains the smallest living vertebrate, and can reach long and weigh .
Trout-perch and allies (Percopsiformes)
The largest species in this small order (both by number of species and body size) is the sand roller (Percopsis transmontana) of North America. This species can range up to in length and can weigh over .
Flatfish (Pleuronectiformes)
The largest of the well-known and heavily fished flatfish is the Pacific halibut (Hippoglossus stenolepis). This giant can reach and , although fish even approaching this size would be extraordinary these days. The Atlantic halibut (Hippoglossus hippoglossus) is also sometimes titled the largest flatfish, although it has a slightly smaller maximum size, at and .
Beardfish (Polymixiiformes)
The little-known beardfish are sometimes classified with the Beryciformes. The largest beardfish is Polymixia busakhini of the Indo-Pacific, which can range up to in length.
Polypterids and allies (Polypteriformes)
The largest polypterid is Polypterus congicus, which reaches up to in length.
Gulper eels (Saccopharyngiformes)
The largest gulper eel is the pelican eel (Eurypharynx pelecanoides). The pelican eel grows to about in length.
Salmon and allies (Salmoniformes)
The largest species of salmonid is the taimen (Hucho taimen). The biggest recorded taimen was caught in the Kotui River in Russia, and measured and weighed . Some sources claim the largest is the Chinook salmon (Oncorhynchus tshawytscha) of America's Pacific Northwest, although this species falls behind the taimen in maximum size. The maximum size of this fish is and long.
Sculpins (Scorpaeniformes)
Although less venomous than many smaller fish in the same order, the skilfish (Erilepis zonifer) of the North Pacific, is largest sculpin. The maximum size is and the weight can be up to . The Lingcod (Ophiodon elongatus) of the west coast of North America is sometimes listed as the largest sculpin but it is not known to exceed in length or in weight. The Cottidae can range up to and in the cabezon (Scorpaenicthys marmoratus) of coastal North America.
Catfish (Siluriformes)
Most authorities now give the crown of the largest catfish to the Mekong giant catfish, Pangasianodon gigas, which is also considered the heaviest completely freshwater fish. This fish has been recorded at sizes up to and . The closely-related Asian giant pangasius (Pangasius sanitwongsei) can grow to and . Another large species is the wels catfish (Silurus glanis) of Europe and Central Asia, which strongly rivals the proceeding species in weight and could possibly surpass them in length. While wels have been confirmed to , other whiskered giants have been reliably reported to grow to and and less reliably to . In South America there also exists the Brachyplatystoma filamentosum, which can reportedly reach up to and .
Ridgeheads and allies (Stephanoberyciformes)
The largest ridgeheads Poromitra curilensis, a Pacific ridgehead related to the crested bigscale, at up to 18 centimetres standard length (SL; a measurement excluding the caudal fin). Most ridgeheads are well under 10 centimetres SL.
Bristlemouths (Stomiiformes)
The largest of the deep-sea bristlemouths is the short-tailed barbeled dragonfish (Oppostomias micripnus). The top size of a female of this species is probably over and long. In species like the barbeled dragonfish (Idiacanthus atlanticus), the snake-like females can measure up to long, about 50 times as long as the male. Although Idiacanthus is much more slender and is lighter than Oppostomias.
Swamp-eels (Synbranchiformes)
The tropic-dwelling swamp-eels, which are not closely related to true eels, reaches their largest size in the marbled swamp eel (Synbrachus marmoratus) of Central and South America. This fish can range up to and weigh .
Seahorses and allies (Syngnathiformes)
The largest of this diverse order is the red cornetfish (Fistularia petimba), a long, thin species found in all tropical oceans. This fish can reach a length of and a weight of . The largest of the famous, petite seahorses is the big-belly seahorse (Hippocampus abdominalis) found off Australia and New Zealand, which can grow to high and weigh over .
Pufferfishes and allies (Tetraodontiformes)
The starry pufferfish Arothron stellatus is the largest pufferfish in the world, growing to a length of . The largest freshwater pufferfish is the mbu pufferfish (Tetraodon mbu) from the Congo River basin. It attains lengths of . As such, these fish are difficult to adequately house in captivity since they require a very large aquarium and appropriately scaled water filtration. At lengths up to , the stone triggerfish ("Pseudobalistes naufragium") from the eastern Pacific is the largest triggerfish, edging out the titan triggerfish (Balistoides viridescens).
Dories (Zeiformes)
The largest species of dory is the Cape dory (Zeus capensis) reaching a size of and a weight of .
Lobe-finned fish (Sarcopterygii)
The largest living (non-tetrapod) lobe-finned fish is the coelacanth. The average weight of the living West Indian Ocean coelacanth, (Latimeria chalumnae), is , and they can reach up to in length. Specimens can weigh up to . The largest lobe-finned fish of all time was Rhizodus at up to .
Lungfish (Dipnoi)
The largest lungfish, the African lungfish (Protopterus aethiopicus), is smooth, elongated, and cylindrical with deeply embedded scales. The tail is very long and tapers at the end. They can reach a length of up to and may weigh as much as . The pectoral and pelvic fins are also very long and thin, almost spaghetti-like.
See also
Megafauna
List of longest fish
Largest organisms
Largest prehistoric animals
References
Fish
Largest
Heaviest or most massive organisms | List of largest fish | [
"Biology"
] | 7,134 | [
"Heaviest or most massive organisms",
"Organism size"
] |
41,366,705 | https://en.wikipedia.org/wiki/Hoopla%20%28digital%20media%20service%29 | Hoopla (stylized as hoopla) is a web and mobile (Android/iOS) library media streaming platform launched in 2010 for audio books, comics, e-books, movies, music, and TV. Patrons of a library that supports Hoopla have access to its collection of digital media.
Hoopla Digital is a division of Midwest Tape.
Business model
Hoopla is free-of-charge for patrons of participating libraries. The content is paid for by library systems, using a "per circulation transaction model".
Content
Hoopla claims to have over 500,000 content titles across six formats, including over 25,000 comic books. As of November 2016, Hoopla's content comprised 35% audiobooks (for which Hoopla has contracts with publishers such as Blackstone Audio, HarperCollins, Simon & Schuster Audio, Tantor Audio, and others), followed by 22% movies (for which Hoopla has motion picture contracts with publishers such as Disney, Lionsgate, Starz, Warner Bros., and others), 19% music, 12% ebooks, 6% comics, and 6% television. One drawback is that Hoopla has few new bestsellers.
Areas served
Hoopla expanded to serve Australia and New Zealand in June 2021.
Technology
Hoopla content can be borrowed and consumed on the web, or via the native Android or iOS apps. Hoopla broadcasts only in Standard definition unlike most of its competitors such as Kanopy.
Parent company
John Eldred and Jeff Jankowski founded Hoopla's parent company, Midwest Tape, in 1989. Midwest Tape is a library vendor of physical media such as audiobooks, CDs, and DVD/Blu-ray.
Controversy
Hoopla and Midwest Tapes were censured by the Library Freedom Project and Library Futures in a joint statement for hosting what it described as "fascist propaganda", including a recent English translation of A New Nobility of Blood and Soil by Richard Walther Darré of the SS and books related to Holocaust denial, in public library collections without the input from the staff. Criticism was also directed at the inclusion of books on homosexuality, abortion, and vaccines claimed by the Library Freedom Project and Library Futures to be misinformation. On February 17, 2022, Hoopla removed a number of titles after public outcry about Holocaust denial books available on the app under non-fiction.
See also
Kanopy
Libro.fm
OverDrive (maker of Libby)
CloudLibrary
References
Digital media
Video on demand services
Online content distribution
Mass media companies of the United States
Audiobook companies and organizations | Hoopla (digital media service) | [
"Technology"
] | 522 | [
"Multimedia",
"Digital media"
] |
41,366,808 | https://en.wikipedia.org/wiki/Windpost | A windpost is a structural item used in the design and construction of masonry walls to increase lateral wall stability and protect them against damage from horizontal forces imposed by wind pressure, crowd or handrail loads. They are normally constructed from mild steel channel sections, supported at the head and the foot between floor slab levels and/or the principal steelwork sections forming the structural frame of the building. In cavity walls, the windpost will typically be fixed into the inner and outer leafs of the wall by specialist fixings and fastenings at regular intervals along its length. The windposts will be spaced along the walls of the building at regular intervals as calculated by the engineer to suit the required loadings.
In most cases a windpost is a large and very unwieldy element that can often weigh in excess of 400 kg. The manufacture and delivery of both steel and concrete windposts has a significant carbon footprint and once delivered to site, their storage requires large areas to be set aside. The procurement of windposts, including the design process, often requires a lead time of four to five weeks. The length and weight of windposts makes them particularly difficult to manoeuvre into position in confined spaces. When installed as part of an internal wall, significant health and safety risks exist for the installers in lifting the windpost to its vertical position. There is no recognised mechanical lifting method to safely erect windposts.
The properties of steel windposts have inherent fire integrity, acoustic, air tightness and thermal movement issues, all of which require additional measures to achieve specification compliance at extra cost.
Design Methods and Alternatives
Windposts are designed to span vertically, floor to floor and provide lateral support for masonry wall panels. The windposts will usually be restrained by the brickwork and designed as simply supported beams.
As an alternative to steel windposts, when the primary structure is composed of reinforced concrete, secondary structures are cast in situ to provide lateral support to masonry panels.
Traditional design methods are often not optimised for the design of masonry panels with openings, and therefore windposts can be over specified on walls where the design capacity may not be utilised. Using alternative design methods such as advanced yield line analysis, the specification of wind posts within masonry wall panels can often be optimised and often omitted. These calculations can be typically carried out by structural engineering software packages such as MasterSeries.
Recently, a new innovative technique of reinforcing blockwork walls has been developed by Wembley Innovation Ltd and used in many Crossrail projects in the UK. It consists of using uniquely designed hollow blocks to allow the construction of reinforced concrete beams (Wi Beams) and columns (Wi Columns) within the blockwork construction, which eliminate the need for traditional windposts or lintels.
This new technique maximises masonry wall strength without thickening the wall or harming its appearance and allows the architects to design and create uninterrupted blockwork panels with flexible detailing options, whilst retaining the performance characteristics of traditional masonry such as fire integrity, acoustic performance and air permeability. This modular approach also provides the adaptability for contractors to make late changes to construction without affecting the build programme and creates seamless walls which do not require any fire protection.
References
Structural engineering
Masonry | Windpost | [
"Engineering"
] | 664 | [
"Construction",
"Civil engineering",
"Structural engineering",
"Masonry"
] |
41,367,291 | https://en.wikipedia.org/wiki/2MASS%20J0523%E2%88%921403 | 2MASS J0523−1403 is a very-low-mass red dwarf about 40 light-years from Earth in the southern constellation of Lepus, with a very faint visual magnitude of 21.05 and a low effective temperature of 2074 K. It is visible primarily in large telescopes sensitive to infrared light. 2MASS J0523−1403 was first observed as part of the Two Micron All-Sky Survey (2MASS).
Characteristics
2MASS J0523−1403 has a luminosity of , a radius of , and an effective temperature of 1,939 K. This makes this star one of the smallest and coolest main sequence stars. It has a stellar classification of L2.5 and a V−K color index of 9.42. The mass is estimated to be (), though the CARMENES input catalogue estimates a mass around . Observation with the Hubble Space Telescope has detected no companion beyond 0.15 arcsecond. Sporadic radio emissions were detected by the VLA in 2004. H-alpha (Hα) emissions have also been detected, a sign of chromospheric activity.
Hydrogen burning limit
Members of the RECONS group have recently identified 2MASS J0523−1403 as representative of the smallest possible stars. Its small radius is at the local minimums of the radius–luminosity and radius–temperature trends. This local minimum is predicted to occur at the hydrogen burning limit due to differences in the radius-mass relationships of stars and brown dwarfs. Unlike hydrogen-burning stars, brown dwarfs decrease in radius as mass increases due to their cores being supported by degeneracy pressure. As the mass increases an increasing fraction of the brown dwarf is degenerate causing the radius to shrink as mass increases. The minimum stellar mass is estimated to be between 0.07 and 0.077 , comparable to the mass of 2MASS J0523−1403.
See also
OGLE-TR-122B
OGLE-TR-123B
EBLM J0555-57Ab
VB 10
References
Lepus (constellation)
L-type stars
J05233822-1403022
TIC objects | 2MASS J0523−1403 | [
"Astronomy"
] | 458 | [
"Lepus (constellation)",
"Constellations"
] |
41,367,787 | https://en.wikipedia.org/wiki/Emily%20Lakdawalla | Emily Stewart Lakdawalla (born February 8, 1975) is an American planetary geologist and former Senior Editor of The Planetary Society, contributing as both a science writer and a blogger. She has also worked as a teacher and as an environmental consultant. She has performed research work in geology, Mars topography, and science communication and education. Lakdawalla is a science advocate on various social media platforms, interacting with space professionals and enthusiasts on Facebook, Google+ and Twitter. She has appeared on such media outlets as NPR, BBC and BBC America.
Education
In 1996, Lakdawalla was awarded her Bachelor of Arts degree in geology from Amherst College. In 2000 she received her Master of Science degree in planetary geology from Brown University.
Career
After completing her studies at Amherst, Lakdawalla spent two years, from 1996 through 1998, teaching fifth and sixth grade science at Lake Forest Country Day School in Lake Forest, Illinois.
In 1997, inspired by a space simulation project using images returning from the Galileo mission of two of Jupiter's moons, Io and Europa, Lakdawalla decided to undertake independent research in structural geology.
Research
At Amherst, Lakdawalla worked to study deformed metasedimentary rocks of northeastern Washington. Working at Brown concurrently, she performed analyses of radar images received from Magellan, while also processing topographic data taken of the Baltis Vallis region on Venus, in order to model its geological history.
Lakdawalla has published research on the topography of a putative stratovolcano on Mars, recorded by the Mars Orbiter Laser Altimeter. She has also worked with an international team to analyze returned Mars rover data, and to evaluate Devon Island as a test site for unmanned aerial vehicles (UAVs) developed for use on Mars.
Lakdawalla's work with Pamela Gay, et al., on the immersion of audiences in interactive educational astronomy content, has been cited by further research into social media content classification and delivery of content types through social media.
Lakdawalla has also engaged in advocacy for citizen science research projects, especially those involving space exploration, such as CosmoQuest and Zooniverse.
The Planetary Society
In 2001, Lakdawalla joined The Planetary Society as a deputy project manager of the Society's Red Rover Goes to Mars project, an educational and public outreach program on the Mars Exploration Rover mission funded by The Lego Group. In 2002, in support of training exercises for Mars rover operations, she administered an international competition, which selected secondary school students for training and travel to Pasadena, California for participation in these exercises. In early 2005, this competition and selection was performed again for actual Mars Exploration Rover mission operations.
During a research operation on Devon Island (located in the Canadian high Arctic), which was funded by The Planetary Society, where a team worked to test the location as a potential analogue for unmanned aerial vehicles to be deployed on Mars, Lakdawalla began writing for the Society's online publications. For several years, she wrote web news articles, as well as making contributions to the society's print publications, including The Planetary Report, where she assumed chief editorial responsibilities in September 2018. Lakdawalla left the Planetary Society in September of 2020
Writing
Lakdawalla is a contributing editor to Sky & Telescope magazine, for which she has written articles about Mars, the Moon, outer planets, spacecraft imaging, and Kuiper belt objects. She has written a book about the design and engineering of the Curiosity rover mission, published in 2018, and is working on a second book, about the scientific discoveries of Curiosity, to be published in 2019.
Starting in September 2013, Lakdawalla has penned the monthly "In the Press" column for Nature Geoscience.
Media appearances
Lakdawalla is a regular contributor to the weekly Planetary Radio podcast.
Following Bill Nye's installation as The Planetary Society's Executive Director, Lakdawalla has appeared on television, in webcasts, on Google+ Hangouts, and on Snapshots from Space, viewable from The Planetary Society's YouTube channel.
Lakdawalla has been a host for CosmoQuest's Science Hour, interviewing guests, including Bill Nye, about the future of planetary exploration.
In an interview with Brad Allen, Lakdawalla discussed the path that led to a career in science communication, the state of human space exploration and current space exploration missions, such as the Mars Science Laboratory.
In a December 2013 interview with Universe Today, Lakdawalla discussed candidate locations for life in the Solar System based on geological activity and presence of water. In addition to Europa, Lakdawalla cited Enceladus (a moon of Saturn), due to its active salty geysers: "Those geysers are salty – it's a salt water ocean, so we basically have a world that is conveniently venting its ocean out into space. You don't even have to land – you can just fly right through that plume and check to see what kinds of cool chemistry is happening there. So yeah, I think Enceladus would be a really cool place to explore for life."
Lakdawalla has been interviewed on topics such as China's Jade Rabbit moon rover on NPR's All Things Considered, and she has also appeared on BBC America and BBC World News.
Awards and honors
In 2011, Lakdawalla received the Jonathan Eberhart Planetary Sciences Journalism Award from the Division for Planetary Sciences of the American Astronomical Society for her reporting on the Phoebe ring of Saturn.
Asteroid 274860 Emilylakdawalla, discovered by German astronomers Matthias Busch and Rainer Kresken at the ESA Optical Ground Station in 2009, was named in her honor. The official was published by the Minor Planet Center on July 12, 2014 ().
Personal life
Lakdawalla resides in Los Angeles with her husband, economist Darius Lakdawalla. The couple originally met when attending Amherst together as undergraduates in the early 1990s. They have two daughters.
See also
Darius Lakdawalla
Neil deGrasse Tyson
Phil Plait
References
Bibliography
External links
1975 births
Living people
Planetary scientists
Women planetary scientists
American women astronomers
American science writers
Science bloggers
21st-century science writers
Amherst College alumni
Brown University alumni
American women bloggers
American bloggers
Women science writers
Sky & Telescope people
American women non-fiction writers
21st-century American non-fiction writers
21st-century American women writers | Emily Lakdawalla | [
"Technology"
] | 1,337 | [
"Women science writers",
"Women in science and technology"
] |
41,368,427 | https://en.wikipedia.org/wiki/Sascha%20Pohflepp | Sascha Pohflepp (30 January 1978 – 17 June 2019) was a German artist, designer, and writer whose work focused on the role of technology’s influence on the environment, often collaborating with scientists and other artists to explore this theme.
Biography
Born in Cologne, Pohflepp received his diploma at the Berlin University of the Arts in 2006 under media artist and designer Joachim Sauter, after studying during a guest term at the École Nationale Supérieure des Arts Décoratifs (ENSAD) in Paris with . In 2009, he received is Masters of Arts in Design Interactions at the Royal College of Art in London, UK, where he worked with Anthony Dunne & Fiona Raby, Noam Toran.
In 2015, Pohflepp began his doctoral work with Benjamin H. Bratton in the PhD Program in Art History, Theory and Criticism with a concentration in Art Practice in the Department of Visual Arts at the University of California, San Diego. In Fall 2018, he advanced to candidacy with dissertation research on a new theory of "post-rational design", which interrelates discourses on the inhuman with the assemblage theory of Gilles Deleuze and Felix Guattari and a rethinking of the Anthropocene. This project was influenced by his participation in the graduate specialization track in anthropogeny at the Center for Academic Research & Training in Anthropogeny (CARTA) at the University of California, San Diego, where he was an Annette Merle-Smith Fellow and worked with the anthropologist Pascal Gagneux.
As an artist and designer, Pohflepp explored these ideas in such works as Growth Assembly (2009, with Alexandra Daisy Ginsberg, illustrations by Sion Ap Tomos); Spacewalk (2017); Deep Unlearning (I) (2018, with Chris Woebken); and Those Who (2019).
Work
Pohflepp created work on the subjects of synthetic biology, geo-engineering, artificial intelligence, and space exploration, and been credited with extending the framework of Critical Design into the realm of elaborate Counterfactuals and other modes of narrative.
His work has been included in numerous international exhibitions, including Talk to Me: Design and Communication between People and Objects at the Museum of Modern Art in New York; Grow Your Own: Life After Nature at The Science Gallery in Dublin; Hyperlinks: Architecture and Design at The Art Institute of Chicago; and New Order at the Mediamatic Fabriek in Amsterdam. He received two Honorary Mentions from the VIDA Art and Artificial Life Awards and was an Eyebeam resident in 2013. In 2015, he was shortlisted for the Berlin Art Prize.
His essay "Living Machines," co-authored with Sheref S. Mansy, is part of the 2017 book, Synthetic Aesthetics: Investigating Synthetic Biology's Designs on Nature published with MIT Press.
References
External links
Sascha Pohflepp anthropocene-curriculum.org
Sascha Pohflepp hkw.de
Sascha Pohflepp rca.ac.uk
Sascha Pohflepp: Power Points of the Far Future www.hmkv.de
Artists from Cologne
Synthetic biology artists
1978 births
2019 deaths
21st-century German artists
Berlin University of the Arts alumni | Sascha Pohflepp | [
"Biology"
] | 672 | [
"Synthetic biology",
"Synthetic biology artists"
] |
41,369,222 | https://en.wikipedia.org/wiki/Diiron%20propanedithiolate%20hexacarbonyl | Diiron propanedithiolate hexacarbonyl is the organoiron complex with the formula Fe2(S2C3H6)(CO)6. It is a red diamagnetic solid. It adopts a symmetrical structure with six terminal CO ligands. The complex is a precursor to hydrogenase mimics.
It is prepared by the reaction of 1,3-propanedithiol with triiron dodecacarbonyl:
2 Fe3(CO)12 + 3 C3H6(SH)2 → 3 Fe2(S2C3H6)(CO)6 + 3 H2 + 6 CO
In general, the CO ligands can be substituted by cyanide, phosphines, isocyanides, N-heterocyclic carbenes, and other donor ligands. Monosubstitution can be achieved through an in situ generation of the acetonitrile complex.
Upon irradiation of Fe2(S2C3H6)(CO)6 with ultraviolet (UV) light, CO-photolysis occurs with the transient formation of the unsaturated species followed by the formation of the solvent adduct.
References
Carbonyl complexes
Organoiron compounds
Thiolates
Chemical compounds containing metal–metal bonds | Diiron propanedithiolate hexacarbonyl | [
"Chemistry"
] | 273 | [
"Thiolates",
"Functional groups"
] |
41,369,887 | https://en.wikipedia.org/wiki/Iqbal%20Hussain%20Qureshi | Iqbal Hussain Qureshi (Urdu:اقبال حسين قریشی) 27 September 1937 – 8 December 2012) , best known as I.H. Qureshi, was a Pakistani nuclear chemist and an Emeritus professor of chemistry at the University of Karachi. Qureshi was the principal contributor of scientific understanding of various chemical elements: bismuth, cobalt, strontium, thallium, tritium, iron, rubidium, and zinc.
His career was mostly spent with the Government of Pakistan after leaving his research work at the national laboratories, and advising the government on nuclear policy issues. He pushed his influential role at the Nuclear Regulatory Authority (PNRA) and the peaceful applications of nuclear science. He spent many years as an educator and research scientist at the Institute of Engineering and Applied Sciences in Nilore before taking a professorship at the Karachi University.
Biography
Iqbal Hussain Qureshi was born on 27 September 1937 in Ajmer, Rajasthan in India where he received his early education. Following the Partition of India in 1947, his family emigrated to Pakistan and settled in Hyderabad, Sindh, where he matriculated from a public high school. He was a child prodigy, being accepted at the Sindh University in his teenage years to study chemistry. In 1956, he graduated with a Bachelor of Science (BSc) in chemistry from the Sindh University and was noted in newspapers for his top standing in his class, winning the silver medallion with his degree. He continued his studies at the Sindh University, and graduated in 1958 with a Master of Science (MSc) in chemistry with Gold medallion.
After earning a scholarship from the Pakistan Atomic Energy Commission (PAEC) in 1960, Qureshi went to the United States to attend the University of Michigan and graduated in 1962 with an MSc in nuclear chemistry. He went to Japan for his doctoral studies, attending the University of Tokyo where in 1963 he defended his thesis, "Radiochemical separations by Amalgam exchange", which contained fundamental work on chemical amalgam applications in radiochemistry. In 1994, his biography was written and published by the University of Michigan in American Men & Women of Science: A Biographical Directory of Today's Leaders in Physical, Biological, and Related Sciences journal.
In 1967, Qureshi returned to the United States and briefly worked for the US National Bureau of Standards as a postdoctoral researcher before leaving for Denmark in 1969. In Denmark, he received training in the areas of uranium and plutonium isotope separation, which was vital when he returned to Pakistan in 1971 with his expertise and knowledge.
Pakistan Atomic Energy Commission
In 1960, Qureshi found employment with the Pakistan Atomic Energy Commission (PAEC), and was posted to the Atomic Energy Center in Lahore where his interest built in radiochemistry. Upon returning to Pakistan from Denmark in 1971, he joined the Institute of Nuclear Science and Technology (the national lab) in Nilore, working at the Nuclear Chemistry Division (NCD).
As early as 1972, Qureshi joined the team of scientists that began working on the equation of state of the radioactive decay element plutonium, while he established the computerized radiation detection chemical analysis laboratories at the Pakistan Institute of Nuclear Science and Technology in 1973. In 1974, Qureshi and his team was instrumental at the national laboratory when he was the first to confirm the detection of radiation emissions coming from Rajasthan in India. Hence, by using neutron activation analysis, confirming Pokhran-I the first Indian nuclear test, which India later announced was indeed conducted at the Pokhran Test Range. Notably, he led the team that balanced the chemical equation required for the exothermic chemical reaction in fission devices. By 1977, he discovered the technique for balancing the nuclear Q-value and energy balance in a boosted fission weapon.
Eventually, Qureshi headed the Nuclear Chemistry Division (NCD) at the Institute of Nuclear Science and Technology which was responsible for the multi-stage chemical process that separated, concentrated and isolated plutonium from uranium. At NCD, he also played a supervisory role in developing the Analytical Chemistry Group comprising modern and state of the art analytical chemistry laboratories such as the Analytical Chemistry Laboratory, Atomic Absorption Spectroscopy lab, Emission Spectrography lab, Chromatography lab, Electrochemical Analysis lab and radioisotope production labs. The Analytical Chemistry Laboratory was later certified by the International Atomic Energy Agency (IAEA), and oversaw the successful commissioning of the PARR-III reactor that went 'phase critical' in 1973.
Qureshi engaged in research about copper-nickel alloys after introducing the lattice dynamical method to evaluate the Cu29/Ni28 alloys. Key and fundamental research on understanding neutron flux was carried out by Qureshi, for which he managed to secure patents from the IAEA. After the conclusion of the Pakistan's clandestine atomic bomb projects, he was appointed chief technical officer at the Pakistan Atomic Energy Commission (PAEC) in 1991; though he was more eager to return to academia.
Throughout his time at PAEC, Qureshi earned several scientific honors, including the Gold Medal and a Fellowship of the Pakistan Academy of Sciences in 1994. He was a recipient of the Sitara-i-Imtiaz (Star of Excellence) from the Government of Pakistan in 1992. In 1997, from the Iranian Government, he received the Khwarizmi International Award for advancing and understanding the "Nuclear analytical techniques development and application in Pakistan".
Academia and government work
In 1996, Qureshi retired from PAEC as Chief Scientific Officer and was made scientist emeritus, which allowed him to continue research at PINSTECH before moving to Karachi. He took up the professorship of chemistry at the Karachi University and headed the nuclear chemistry section at the H.E.J. Research Institute of Chemistry. During this time, he authored several articles and published books on nuclear chemistry. He retained his position till 2001 when he joined the Pakistan Nuclear Regulatory Authority (PNRA).
At PNRA, Qureshi served as the chief scientific officer and adviser to the government on nuclear policy issues. His contribution and policy efforts led to the physical security of the commercial nuclear power infrastructure in the country and helped launched the nuclear awareness campaign following the Fukushima nuclear disaster in 2011. He served until 2009 when he decided to accept the professorship of chemistry at the Institute of Engineering and Applied Sciences. In December 2012 Qureshi had a sudden breathing problem and died. He is buried in Karachi, Sindh.
Personal life and interests
In Pakistan's academia and nuclear society, Qureshi was well known for his interests in classical music theory and love of playing the guitar and sitar, which he played on several occasions. He also had an interest in American poetry, which he often quoted among his peers while working on the bomb program, and played tennis avidly during his later life. He was married twice; his first wife died in the 1980s and he later remarried. He had two sons, one a neurosurgeon while the other is a computer scientist.
References
External links
Pakistan's nuclear and environment safety issues
Pakistan Academy of Sciences
1937 births
2012 deaths
People from Ajmer
Pakistani people of Rajasthani descent
University of Sindh alumni
University of Michigan alumni
University of Tokyo alumni
Pakistani chemists
Pakistani scientists
Nuclear chemists
Radiochemistry
Pakistani expatriates in the United States
Pakistani expatriates in Japan
Expatriates in Denmark
Project-706
National Institute of Standards and Technology people
Academic staff of Pakistan Institute of Engineering and Applied Sciences
Academic staff of the University of Karachi
Academic staff of Quaid-i-Azam University
Recipients of Sitara-i-Imtiaz
Sitar players
Fellows of Pakistan Academy of Sciences
Nuclear weapons scientists and engineers | Iqbal Hussain Qureshi | [
"Chemistry"
] | 1,560 | [
"Nuclear chemists",
"Radiochemistry",
"Radioactivity"
] |
41,370,976 | https://en.wikipedia.org/wiki/Kernel%20embedding%20of%20distributions | In machine learning, the kernel embedding of distributions (also called the kernel mean or mean map) comprises a class of nonparametric methods in which a probability distribution is represented as an element of a reproducing kernel Hilbert space (RKHS). A generalization of the individual data-point feature mapping done in classical kernel methods, the embedding of distributions into infinite-dimensional feature spaces can preserve all of the statistical features of arbitrary distributions, while allowing one to compare and manipulate distributions using Hilbert space operations such as inner products, distances, projections, linear transformations, and spectral analysis. This learning framework is very general and can be applied to distributions over any space on which a sensible kernel function (measuring similarity between elements of ) may be defined. For example, various kernels have been proposed for learning from data which are: vectors in , discrete classes/categories, strings, graphs/networks, images, time series, manifolds, dynamical systems, and other structured objects. The theory behind kernel embeddings of distributions has been primarily developed by Alex Smola, Le Song , Arthur Gretton, and Bernhard Schölkopf. A review of recent works on kernel embedding of distributions can be found in.
The analysis of distributions is fundamental in machine learning and statistics, and many algorithms in these fields rely on information theoretic approaches such as entropy, mutual information, or Kullback–Leibler divergence. However, to estimate these quantities, one must first either perform density estimation, or employ sophisticated space-partitioning/bias-correction strategies which are typically infeasible for high-dimensional data. Commonly, methods for modeling complex distributions rely on parametric assumptions that may be unfounded or computationally challenging (e.g. Gaussian mixture models), while nonparametric methods like kernel density estimation (Note: the smoothing kernels in this context have a different interpretation than the kernels discussed here) or characteristic function representation (via the Fourier transform of the distribution) break down in high-dimensional settings.
Methods based on the kernel embedding of distributions sidestep these problems and also possess the following advantages:
Data may be modeled without restrictive assumptions about the form of the distributions and relationships between variables
Intermediate density estimation is not needed
Practitioners may specify the properties of a distribution most relevant for their problem (incorporating prior knowledge via choice of the kernel)
If a characteristic kernel is used, then the embedding can uniquely preserve all information about a distribution, while thanks to the kernel trick, computations on the potentially infinite-dimensional RKHS can be implemented in practice as simple Gram matrix operations
Dimensionality-independent rates of convergence for the empirical kernel mean (estimated using samples from the distribution) to the kernel embedding of the true underlying distribution can be proven.
Learning algorithms based on this framework exhibit good generalization ability and finite sample convergence, while often being simpler and more effective than information theoretic methods
Thus, learning via the kernel embedding of distributions offers a principled drop-in replacement for information theoretic approaches and is a framework which not only subsumes many popular methods in machine learning and statistics as special cases, but also can lead to entirely new learning algorithms.
Definitions
Let denote a random variable with domain and distribution . Given a symmetric, positive-definite kernel the Moore–Aronszajn theorem asserts the existence of a unique RKHS on (a Hilbert space of functions equipped with an inner product and a norm ) for which is a reproducing kernel, i.e., in which the element satisfies the reproducing property
One may alternatively consider as an implicit feature mapping (which is therefore also called the feature space), so that can be viewed as a measure of similarity between points While the similarity measure is linear in the feature space, it may be highly nonlinear in the original space depending on the choice of kernel.
Kernel embedding
The kernel embedding of the distribution in (also called the kernel mean or mean map) is given by:
If allows a square integrable density , then , where is the Hilbert–Schmidt integral operator. A kernel is characteristic if the mean embedding is injective. Each distribution can thus be uniquely represented in the RKHS and all statistical features of distributions are preserved by the kernel embedding if a characteristic kernel is used.
Empirical kernel embedding
Given training examples drawn independently and identically distributed (i.i.d.) from the kernel embedding of can be empirically estimated as
Joint distribution embedding
If denotes another random variable (for simplicity, assume the co-domain of is also with the same kernel which satisfies ), then the joint distribution can be mapped into a tensor product feature space via
By the equivalence between a tensor and a linear map, this joint embedding may be interpreted as an uncentered cross-covariance operator from which the cross-covariance of functions can be computed as
Given pairs of training examples drawn i.i.d. from , we can also empirically estimate the joint distribution kernel embedding via
Conditional distribution embedding
Given a conditional distribution one can define the corresponding RKHS embedding as
Note that the embedding of thus defines a family of points in the RKHS indexed by the values taken by conditioning variable . By fixing to a particular value, we obtain a single element in , and thus it is natural to define the operator
which given the feature mapping of outputs the conditional embedding of given Assuming that for all it can be shown that
This assumption is always true for finite domains with characteristic kernels, but may not necessarily hold for continuous domains. Nevertheless, even in cases where the assumption fails, may still be used to approximate the conditional kernel embedding and in practice, the inversion operator is replaced with a regularized version of itself (where denotes the identity matrix).
Given training examples the empirical kernel conditional embedding operator may be estimated as
where are implicitly formed feature matrices, is the Gram matrix for samples of , and is a regularization parameter needed to avoid overfitting.
Thus, the empirical estimate of the kernel conditional embedding is given by a weighted sum of samples of in the feature space:
where and
Properties
The expectation of any function in the RKHS can be computed as an inner product with the kernel embedding:
In the presence of large sample sizes, manipulations of the Gram matrix may be computationally demanding. Through use of a low-rank approximation of the Gram matrix (such as the incomplete Cholesky factorization), running time and memory requirements of kernel-embedding-based learning algorithms can be drastically reduced without suffering much loss in approximation accuracy.
Convergence of empirical kernel mean to the true distribution embedding
If is defined such that takes values in for all with (as is the case for the widely used radial basis function kernels), then with probability at least :
where denotes the unit ball in and is the Gram matrix with
The rate of convergence (in RKHS norm) of the empirical kernel embedding to its distribution counterpart is and does not depend on the dimension of .
Statistics based on kernel embeddings thus avoid the curse of dimensionality, and though the true underlying distribution is unknown in practice, one can (with high probability) obtain an approximation within of the true kernel embedding based on a finite sample of size .
For the embedding of conditional distributions, the empirical estimate can be seen as a weighted average of feature mappings (where the weights depend on the value of the conditioning variable and capture the effect of the conditioning on the kernel embedding). In this case, the empirical estimate converges to the conditional distribution RKHS embedding with rate if the regularization parameter is decreased as though faster rates of convergence may be achieved by placing additional assumptions on the joint distribution.
Universal kernels
Let be a compact metric space and the set of continuous functions. The reproducing kernel is called universal if and only if the RKHS of is dense in , i.e., for any and all there exists an such that . All universal kernels defined on a compact space are characteristic kernels but the converse is not always true.
Let be a continuous translation invariant kernel with . Then Bochner's theorem guarantees the existence of a unique finite Borel measure (called the spectral measure) on such that
For to be universal it suffices that the continuous part of in its unique Lebesgue decomposition is non-zero. Furthermore, if
then is the spectral density of frequencies in and is the Fourier transform of . If the support of is all of , then is a characteristic kernel as well.
If induces a strictly positive definite kernel matrix for any set of distinct points, then it is a universal kernel. For example, the widely used Gaussian RBF kernel
on compact subsets of is universal.
Parameter selection for conditional distribution kernel embeddings
The empirical kernel conditional distribution embedding operator can alternatively be viewed as the solution of the following regularized least squares (function-valued) regression problem
where is the Hilbert–Schmidt norm.
One can thus select the regularization parameter by performing cross-validation based on the squared loss function of the regression problem.
Rules of probability as operations in the RKHS
This section illustrates how basic probabilistic rules may be reformulated as (multi)linear algebraic operations in the kernel embedding framework and is primarily based on the work of Song et al. The following notation is adopted:
joint distribution over random variables
marginal distribution of ; marginal distribution of
conditional distribution of given with corresponding conditional embedding operator
prior distribution over
is used to distinguish distributions which incorporate the prior from distributions which do not rely on the prior
In practice, all embeddings are empirically estimated from data and it assumed that a set of samples may be used to estimate the kernel embedding of the prior distribution .
Kernel sum rule
In probability theory, the marginal distribution of can be computed by integrating out from the joint density (including the prior distribution on )
The analog of this rule in the kernel embedding framework states that the RKHS embedding of , can be computed via
where is the kernel embedding of In practical implementations, the kernel sum rule takes the following form
where
is the empirical kernel embedding of the prior distribution, , and are Gram matrices with entries respectively.
Kernel chain rule
In probability theory, a joint distribution can be factorized into a product between conditional and marginal distributions
The analog of this rule in the kernel embedding framework states that the joint embedding of can be factorized as a composition of conditional embedding operator with the auto-covariance operator associated with
where
In practical implementations, the kernel chain rule takes the following form
Kernel Bayes' rule
In probability theory, a posterior distribution can be expressed in terms of a prior distribution and a likelihood function as
where
The analog of this rule in the kernel embedding framework expresses the kernel embedding of the conditional distribution in terms of conditional embedding operators which are modified by the prior distribution
where from the chain rule:
In practical implementations, the kernel Bayes' rule takes the following form
where
Two regularization parameters are used in this framework: for the estimation of and for the estimation of the final conditional embedding operator
The latter regularization is done on square of because may not be positive definite.
Applications
Measuring distance between distributions
The maximum mean discrepancy (MMD) is a distance-measure between distributions and which is defined as the distance between their embeddings in the RKHS
While most distance-measures between distributions such as the widely used Kullback–Leibler divergence either require density estimation (either parametrically or nonparametrically) or space partitioning/bias correction strategies, the MMD is easily estimated as an empirical mean which is concentrated around the true value of the MMD. The characterization of this distance as the maximum mean discrepancy refers to the fact that computing the MMD is equivalent to finding the RKHS function that maximizes the difference in expectations between the two probability distributions
a form of integral probability metric.
Kernel two-sample test
Given n training examples from and m samples from , one can formulate a test statistic based on the empirical estimate of the MMD
to obtain a two-sample test of the null hypothesis that both samples stem from the same distribution (i.e. ) against the broad alternative .
Density estimation via kernel embeddings
Although learning algorithms in the kernel embedding framework circumvent the need for intermediate density estimation, one may nonetheless use the empirical embedding to perform density estimation based on n samples drawn from an underlying distribution . This can be done by solving the following optimization problem
subject to
where the maximization is done over the entire space of distributions on Here, is the kernel embedding of the proposed density and is an entropy-like quantity (e.g. Entropy, KL divergence, Bregman divergence). The distribution which solves this optimization may be interpreted as a compromise between fitting the empirical kernel means of the samples well, while still allocating a substantial portion of the probability mass to all regions of the probability space (much of which may not be represented in the training examples). In practice, a good approximate solution of the difficult optimization may be found by restricting the space of candidate densities to a mixture of M candidate distributions with regularized mixing proportions. Connections between the ideas underlying Gaussian processes and conditional random fields may be drawn with the estimation of conditional probability distributions in this fashion, if one views the feature mappings associated with the kernel as sufficient statistics in generalized (possibly infinite-dimensional) exponential families.
Measuring dependence of random variables
A measure of the statistical dependence between random variables and (from any domains on which sensible kernels can be defined) can be formulated based on the Hilbert–Schmidt Independence Criterion
and can be used as a principled replacement for mutual information, Pearson correlation or any other dependence measure used in learning algorithms. Most notably, HSIC can detect arbitrary dependencies (when a characteristic kernel is used in the embeddings, HSIC is zero if and only if the variables are independent), and can be used to measure dependence between different types of data (e.g. images and text captions). Given n i.i.d. samples of each random variable, a simple parameter-free unbiased estimator of HSIC which exhibits concentration about the true value can be computed in time, where the Gram matrices of the two datasets are approximated using with . The desirable properties of HSIC have led to the formulation of numerous algorithms which utilize this dependence measure for a variety of common machine learning tasks such as: feature selection (BAHSIC ), clustering (CLUHSIC ), and dimensionality reduction (MUHSIC ).
HSIC can be extended to measure the dependence of multiple random variables. The question of when HSIC captures independence in this case has recently been studied: for
more than two variables
on : the characteristic property of the individual kernels remains an equivalent condition.
on general domains: the characteristic property of the kernel components is necessary but not sufficient.
Kernel belief propagation
Belief propagation is a fundamental algorithm for inference in graphical models in which nodes repeatedly pass and receive messages corresponding to the evaluation of conditional expectations. In the kernel embedding framework, the messages may be represented as RKHS functions and the conditional distribution embeddings can be applied to efficiently compute message updates. Given n samples of random variables represented by nodes in a Markov random field, the incoming message to node t from node u can be expressed as
if it assumed to lie in the RKHS. The kernel belief propagation update message from t to node s is then given by
where denotes the element-wise vector product, is the set of nodes connected to t excluding node s, , are the Gram matrices of the samples from variables , respectively, and is the feature matrix for the samples from .
Thus, if the incoming messages to node t are linear combinations of feature mapped samples from , then the outgoing message from this node is also a linear combination of feature mapped samples from . This RKHS function representation of message-passing updates therefore produces an efficient belief propagation algorithm in which the potentials are nonparametric functions inferred from the data so that arbitrary statistical relationships may be modeled.
Nonparametric filtering in hidden Markov models
In the hidden Markov model (HMM), two key quantities of interest are the transition probabilities between hidden states and the emission probabilities for observations. Using the kernel conditional distribution embedding framework, these quantities may be expressed in terms of samples from the HMM. A serious limitation of the embedding methods in this domain is the need for training samples containing hidden states, as otherwise inference with arbitrary distributions in the HMM is not possible.
One common use of HMMs is filtering in which the goal is to estimate posterior distribution over the hidden state at time step t given a history of previous observations from the system. In filtering, a belief state is recursively maintained via a prediction step (where updates are computed by marginalizing out the previous hidden state) followed by a conditioning step (where updates are computed by applying Bayes' rule to condition on a new observation). The RKHS embedding of the belief state at time t+1 can be recursively expressed as
by computing the embeddings of the prediction step via the kernel sum rule and the embedding of the conditioning step via kernel Bayes' rule. Assuming a training sample is given, one can in practice estimate
and filtering with kernel embeddings is thus implemented recursively using the following updates for the weights
where denote the Gram matrices of and respectively, is a transfer Gram matrix defined as and
Support measure machines
The support measure machine (SMM) is a generalization of the support vector machine (SVM) in which the training examples are probability distributions paired with labels . SMMs solve the standard SVM dual optimization problem using the following expected kernel
which is computable in closed form for many common specific distributions (such as the Gaussian distribution) combined with popular embedding kernels (e.g. the Gaussian kernel or polynomial kernel), or can be accurately empirically estimated from i.i.d. samples via
Under certain choices of the embedding kernel , the SMM applied to training examples is equivalent to a SVM trained on samples , and thus the SMM can be viewed as a flexible SVM in which a different data-dependent kernel (specified by the assumed form of the distribution ) may be placed on each training point.
Domain adaptation under covariate, target, and conditional shift
The goal of domain adaptation is the formulation of learning algorithms which generalize well when the training and test data have different distributions. Given training examples and a test set where the are unknown, three types of differences are commonly assumed between the distribution of the training examples and the test distribution :<ref name = "DA">K. Zhang, B. Schölkopf, K. Muandet, Z. Wang. (2013). Domain adaptation under target and conditional shift. Journal of Machine Learning Research, 28(3): 819–827.</ref>
Covariate shift in which the marginal distribution of the covariates changes across domains:
Target shift in which the marginal distribution of the outputs changes across domains:
Conditional shift in which remains the same across domains, but the conditional distributions differ: . In general, the presence of conditional shift leads to an ill-posed problem, and the additional assumption that changes only under location-scale (LS) transformations on is commonly imposed to make the problem tractable.
By utilizing the kernel embedding of marginal and conditional distributions, practical approaches to deal with the presence of these types of differences between training and test domains can be formulated. Covariate shift may be accounted for by reweighting examples via estimates of the ratio obtained directly from the kernel embeddings of the marginal distributions of in each domain without any need for explicit estimation of the distributions. Target shift, which cannot be similarly dealt with since no samples from are available in the test domain, is accounted for by weighting training examples using the vector which solves the following optimization problem (where in practice, empirical approximations must be used)
subject to
To deal with location scale conditional shift, one can perform a LS transformation of the training points to obtain new transformed training data (where denotes the element-wise vector product). To ensure similar distributions between the new transformed training samples and the test data, are estimated by minimizing the following empirical kernel embedding distance
In general, the kernel embedding methods for dealing with LS conditional shift and target shift may be combined to find a reweighted transformation of the training data which mimics the test distribution, and these methods may perform well even in the presence of conditional shifts other than location-scale changes.
Domain generalization via invariant feature representation
Given N sets of training examples sampled i.i.d. from distributions , the goal of domain generalization is to formulate learning algorithms which perform well on test examples sampled from a previously unseen domain where no data from the test domain is available at training time. If conditional distributions are assumed to be relatively similar across all domains, then a learner capable of domain generalization must estimate a functional relationship between the variables which is robust to changes in the marginals . Based on kernel embeddings of these distributions, Domain Invariant Component Analysis (DICA) is a method which determines the transformation of the training data that minimizes the difference between marginal distributions while preserving a common conditional distribution shared between all training domains. DICA thus extracts invariants, features that transfer across domains, and may be viewed as a generalization of many popular dimension-reduction methods such as kernel principal component analysis, transfer component analysis, and covariance operator inverse regression.
Defining a probability distribution on the RKHS with
DICA measures dissimilarity between domains via distributional variance which is computed as
where
so is a Gram matrix over the distributions from which the training data are sampled. Finding an orthogonal transform onto a low-dimensional subspace B (in the feature space) which minimizes the distributional variance, DICA simultaneously ensures that B aligns with the bases of a central subspace C for which becomes independent of given across all domains. In the absence of target values , an unsupervised version of DICA may be formulated which finds a low-dimensional subspace that minimizes distributional variance while simultaneously maximizing the variance of (in the feature space) across all domains (rather than preserving a central subspace).
Distribution regression
In distribution regression, the goal is to regress from probability distributions to reals (or vectors). Many important machine learning and statistical tasks fit into this framework, including multi-instance learning, and point estimation problems without analytical solution (such as hyperparameter or entropy estimation). In practice only samples from sampled distributions are observable, and the estimates have to rely on similarities computed between sets of points''. Distribution regression has been successfully applied for example in supervised entropy learning, and aerosol prediction using multispectral satellite images.
Given training data, where the bag contains samples from a probability distribution and the output label is , one can tackle the distribution regression task by taking the embeddings of the distributions, and learning the regressor from the embeddings to the outputs. In other words, one can consider the following kernel ridge regression problem
where
with a kernel on the domain of -s , is a kernel on the embedded distributions, and is the RKHS determined by . Examples for include the linear kernel , the Gaussian kernel , the exponential kernel , the Cauchy kernel , the generalized t-student kernel , or the inverse multiquadrics kernel .
The prediction on a new distribution takes the simple, analytical form
where , , , . Under mild regularity conditions this estimator can be shown to be consistent and it can achieve the one-stage sampled (as if one had access to the true -s) minimax optimal rate. In the objective function -s are real numbers; the results can also be extended to the case when -s are -dimensional vectors, or more generally elements of a separable Hilbert space using operator-valued kernels.
Example
In this simple example, which is taken from Song et al., are assumed to be discrete random variables which take values in the set and the kernel is chosen to be the Kronecker delta function, so . The feature map corresponding to this kernel is the standard basis vector . The kernel embeddings of such a distributions are thus vectors of marginal probabilities while the embeddings of joint distributions in this setting are matrices specifying joint probability tables, and the explicit form of these embeddings is
When , for all , the conditional distribution embedding operator,
is in this setting a conditional probability table
and
Thus, the embeddings of the conditional distribution under a fixed value of may be computed as
In this discrete-valued setting with the Kronecker delta kernel, the kernel sum rule becomes
The kernel chain rule in this case is given by
References
External links
Information Theoretical Estimators toolbox (distribution regression demonstration).
Machine learning
Theory of probability distributions | Kernel embedding of distributions | [
"Engineering"
] | 5,211 | [
"Artificial intelligence engineering",
"Machine learning"
] |
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