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51,452,306 | https://en.wikipedia.org/wiki/Frans%20Verbeeck | Frans Verbeeck or Frans Verbeeck the Elder (c. 1510 – 24 July 1570, Mechelen) was a Flemish painter and draughtsman to whom have been attributed a number of works depicting fantastical and grotesque scenes carrying a moralizing intent. He was a member of an important family of artists operating a large workshop with various branches in Mechelen. As it is not always possible to attribute a particular artwork to one or the other family member due to compositional, stylistic, and iconographic similarities, it has been suggested that the works should be attributed to the 'Verbeeck group'. The works were typically executed in tempera or watercolor on linen.
Life
There is very little known with certainty about Frans Verbeeck. He was a member of the Verbeeck family of artists based in Mechelen. There were about 15 painters recorded in the archives of Mechelen with the name Frans Verbeeck. There were also multiple artists with the name Jan Verbeeck active in Mechelen. Frans Verbeeck is the best-known of the artists in the family.
He was likely born around 1510. According to the early Flemish biographer Karel van Mander, Frans Verbeeck was a pupil of Frans Minnebroer in Mechelen. Frans Verbeeck became a master of the local painter's guild in Mechelen in 1531. He was dean of the guild on multiple occasions including in 1563, 1564 and 1565.
The Verbeeck family formed a dynasty of artists producing a large output of paintings in a workshop with multiple branches. They produced mainly compositions of a small scale using tempera rather than oil. The art historian Paul Vandenbroeck proposed in 1981 that the works created in the workshop should be attributed to the 'Verbeeck group', due to the close proximity in composition, style and iconographic language applied. Vandenbroeck felt it was impossible and meaningless to attempt to distinguish between individual family members such as Frans and Jan Verbeeck and attribute these paintings to one or the other artist. Despite the difficulty of distinguishing between the artists in the Verbeeck group, some works have been attributed specifically to Frans Verbeeck. The composition The Mocking of Human Follies (Auctioned at Dorotheum, 21 October 2014, lot 33) was listed in 2003 in the catalogue of exhibition 'De Zotte Schilders' ('The Mad Painters') as a painting by Frans Verbeeck, with the addition 'de Oude', which translates to 'the Elder'. There was also a Frans Verbeeck the Younger who is recorded having pupils between 1608 and 1614.
Work
Frans Verbeeck did not leave any known signed paintings. A fair number of compositions with Hieronymus Bosch-like subjects, that could not be attributed to Bosch followers such as Jan Mandijn or to Pieter Huys, have been attributed to him. The range of his subject matter is very wide and includes religious scenes like The Temptation of St Anthony, satirical subjects of vernacular peasant life, such as The Mocking of Human Follies (Bilbao, Museo de Bellas Artes de Bilbao), allegorical works like The Mocking of Human Follies (Auctioned at Dorotheum, 21 October 2014, lot 33) as well as scenes of witches such as Temptation of Saint Anthony (At Gallerie De Jonckheere) or the Witches' Sabbath (Christie's London sale of 6 December 2018 lot 3).
Frans Verbeeck is known for his depictions of peasant weddings and similar subject matter dealing with satirical and moralistic themes, inspired by Hieronymus Bosch and by the plays performed in the local chambers of rhetoric. Many of his compositions were painted in watercolor, which was the favoured medium of Mechelen artists in the 16th and 17th centuries.
The family Verbeeck seems to be one of the first to have developed the theme of the peasant wedding. Three watercolor paintings on the theme are known, two of which depict carnavalesque weddings and one a joust. One of these paintings entitled Burlesque Feast (Bilbao Fine Arts Museum) was previously ascribed to Jan Mandijn, an attribution which is no longer accepted by art historian Paul Vandenbroeck and the RKD.
Another representative work attributed to Frans Verbeeck is The Mocking of Human Follies, of which there exist two versions, one the original (Auctioned at Dorotheum, 21 October 2014, lot 33) and the other a smaller workshop copy (Auctioned at Dorotheum on 16 October 2007, lot 38).
The subjects of peasant weddings and human follies aimed to criticise in a funny and absurd manner the foolish, animal-like behaviour of man led by lust, desire and impulse. By mocking human follies these scenes were to serve as negative examples of improper behaviour for the urban elite of the Low Countries. The motivation behind, or key to deciphering, many of the allusive, rebuslike details of the compositions in the Verbeeck group can be traced to the satirical texts of the chambers of rhetoric, whose members loved elegantly poking fun at human vices and folly. The humour used in these compositions was direct, obscene and scabrous, with no trace of refinement. These subjects and motives stand in a long line that goes from Hieronymus Bosch (ca. 1450–1516) over Jan Wellens de Cock (ca. 1470–1521), Jan Mandijn (ca. 1500–ca. 1560), Pieter Huys (ca. 1519–ca. 1581) and Frans Verbeeck (ca. 1510/15–1570) to Pieter Brueghel the Elder (1526/30–1569) and further to Pieter Brueghel the Younger (1564–1638).
The Verbeeck family had developed and maintained an individual style with a unique and rich iconography that can be distinguished from the two great Flemish masters of the fantastic and bizarre Hieronymous Bosch and Pieter Brueghel the Elder. The Verbeeck family's world of imagery with its strangeness and sometimes bizarre, caricature-like characteristics offers a very personal vision of the human race inspired by Flemish folklore.
References
External links
Flemish Renaissance painters
Flemish genre painters
Draughtsmen
1510s births
1570 deaths
Painters from Mechelen
Artists from Mechelen | Frans Verbeeck | [
"Engineering"
] | 1,345 | [] |
51,452,627 | https://en.wikipedia.org/wiki/Cucujomyces%20elegans | Cucujomyces elegans is a species of fungus in the family Laboulbeniaceae. It is found in Argentina.
References
Laboulbeniaceae
Fungi described in 1917
Biota of Argentina
Fungus species | Cucujomyces elegans | [
"Biology"
] | 46 | [
"Biota by country",
"Fungi",
"Biota of Argentina",
"Fungus species"
] |
51,453,550 | https://en.wikipedia.org/wiki/Cyanonephron%20elegans | Cyanonephron elegans is a freshwater species of cyanobacteria in the family Synechococcaceae. It is described in the Netherlands, Siberia, Russia and Queensland, Australia.
References
McGregor, G. (2013). Freshwater Cyanobacteria from North-Eastern Australia: 2. Chroococcales. Phytotaxa 133: 1-130
External links
Cyanonephron elegans at algaebase
Synechococcales
Bacteria described in 2006
Biota of Queensland
Biota of the Netherlands
Biota of Siberia | Cyanonephron elegans | [
"Biology"
] | 117 | [
"Biota by country",
"Biota of the Netherlands"
] |
51,453,939 | https://en.wikipedia.org/wiki/Testis-enhanced%20gene%20transfer%20family | The testis-enhanced gene transcript (TEGT) family includes the testis-enhanced gene transcript proteins of mammals, which are expressed at high levels in the testis, the putative glutamate/aspartate binding proteins of plants and animals, the YccA protein of Escherichia coli and the YetJ protein of Bacillus subtilis. These proteins are about 200-250 residues in length and exhibit 7 TMSs.
Homology
Homologues are found in a variety of Gram-negative and Gram-positive bacteria, yeast, fungi, plants, animals and viruses. The E. coli genome encodes three paralogues, YbhL, YbhM and YccA. Distant homologues found in Drosophilia melanogaster and the rat are the N-methyl-D-aspartate receptor-associated protein (NMDARAI) and the N-methyl-D-aspartate receptor glutamate binding chain, respectively. Two others are the rat neural membrane protein 35 and the Arabidopsis thaliana Bax inhibitor-1 (BI-1) protein capable of suppressing Bax-induced cell death in yeast.
BI-1
One of these proteins, TEGT or the Bax Inhibitor-1 (TC# 1.A.14.1.1), has a C-terminal domain that forms a Ca2+-permeable channel. BI-1 is an ER-localized protein that protects against apoptosis and ER stress. BI-1 has been proposed to modulate ER Ca2+ homeostasis by acting as a Ca2+-leak channel. These proteins are distantly related to the ionotropic glutamate-binding protein of the N-methyl D-aspartate (NMDA) receptor of man. Homologues include a putative cold shock inducible protein and a SecY stabilizing protein.
Function
Based on experimental determination of the BI-1 topology, Bultynck et al. proposes that its C-terminal α-helical 20 amino acid peptide catalyzes Ca2+ flux both in vivo and in vitro. The Ca2+-leak properties were conserved among animal, but not plant and yeast orthologs. By mutating one of the critical aspartate residues (D213) in the proposed Ca2+-channel pore in full-length BI-1, D213 proved to be essential for BI-1 dependent ER Ca2+-leak.
Structure
Chang et al. published crystal structures of a bacterial homolog, YetJ (TC# 1.A.14.2.3) at 1.9 Å resolution and characterized its calcium leak activity. Its seven-transmembrane-helix fold features two triple-helix sandwiches wrapped around a central C-terminal helix. Structures obtained in closed and open conformations are reversibly interconvertible by changes in the pH. A hydrogen-bonded perturbed pair of conserved aspartyl residues explains the pH dependence of this transition, and the pH regulates calcium influx in proteoliposomes. Homology models for human BI-1 provided insight into its cytoprotective activity.
Transport Reaction
The generalized reaction catalyzed by TEGT channels is:
cations (out) ⇌ cations (in)
References
Protein families
Membrane proteins
Transmembrane proteins
Transmembrane transporters
Transport proteins
Integral membrane proteins | Testis-enhanced gene transfer family | [
"Biology"
] | 715 | [
"Protein families",
"Protein classification",
"Membrane proteins"
] |
51,454,694 | https://en.wikipedia.org/wiki/Germanium-tin | Germanium-tin is an alloy of the elements germanium and tin, both located in group 14 of the periodic table. It is only thermodynamically stable under a small composition range. Despite this limitation, it has useful properties for band gap and strain engineering of silicon-integrated optoelectronic and microelectronic semiconductor devices.
Synthesis
Germanium-tin alloys must be kinetically stabilized in order to prevent decomposition. Therefore, low temperature molecular beam epitaxy or chemical vapor deposition techniques are typically used for their synthesis.
Microelectronic applications
Germanium-tin alloys have higher carrier mobilities than either silicon or germanium. Therefore, it has been proposed that they can be used as a channel material in high speed metal-oxide-semiconductor field effect transistors. In addition, the alloys' larger lattice constant relative to germanium makes it possible to use them as stressors to enhance the carrier mobility of germanium channel transistors.
Optoelectronic applications
At a Sn content beyond approximately 9%, germanium-tin alloys become direct gap semiconductors having efficient light emission suitable for the fabrication of lasers. Since the constituent elements are chemically compatible with silicon, it is possible to integrate such lasers directly onto silicon microelectronic devices, enabling on-chip optical communication. This is still an active research area, but germanium-tin lasers operating at low temperatures have already been demonstrated. In addition, germanium-tin light emitting diodes operating at room temperature have also been reported.
References
Germanium
Tin alloys | Germanium-tin | [
"Chemistry"
] | 324 | [
"Tin alloys",
"Alloys"
] |
51,454,896 | https://en.wikipedia.org/wiki/Quantitative%20systems%20pharmacology | Quantitative systems pharmacology (QSP) is a discipline within biomedical research that uses mathematical computer models to characterize biological systems, disease processes and drug pharmacology. QSP can be viewed as a sub-discipline of pharmacometrics that focuses on modeling the mechanisms of drug pharmacokinetics (PK), pharmacodynamics (PD), and disease processes using a systems pharmacology point of view. QSP models are typically defined by systems of ordinary differential equations (ODE) that depict the dynamical properties of the interaction between the drug and the biological system.
QSP can be used to generate biological/pharmacological hypotheses in silico to aid in the design of in vitro or in vivo non-clinical and clinical experiments. This can help to guide biomedical experiments so that they yield more meaningful data. QSP is increasingly being used for this purpose in pharmaceutical research & development to help guide the discovery and development of new therapies. QSP has been used by the FDA in a clinical pharmacology review.
Origin
QSP emerged as a discipline through two workshops held at the National Institutes of Health (NIH) in 2008 and 2010, with the goal of merging of systems biology and pharmacology. The workshops outlined a need for a mathematical discipline to aid in translational medicine. QSP proposed integrating concepts, methods, and investigators from computational biology, systems biology, and biological engineering into pharmacology.
A review of the history and future of QSP identified areas where it has advanced understanding of drug mechanisms, supported preclinical to clinical translation, and in general aided in drug development. The FDA has included QSP as a component of the Model-Informed Drug Development Program.
References
External links
QSP Special Interest Group at ISoP
QSP as Simulations Plus
QSP at Certara
eBook: The Emerging Discipline of Quantitative Systems Pharmacology
The UK QSP Network
Pharmacology | Quantitative systems pharmacology | [
"Chemistry"
] | 408 | [
"Pharmacology",
"Medicinal chemistry"
] |
51,454,915 | https://en.wikipedia.org/wiki/Blastocladia%20angusta | Blastocladia angusta is a species of fungus.
References
External links
Mycobank entry
Fungi described in 1834
Blastocladiomycota
Fungus species | Blastocladia angusta | [
"Biology"
] | 34 | [
"Fungus stubs",
"Fungi",
"Fungus species"
] |
51,456,280 | https://en.wikipedia.org/wiki/Magnesium%20transporter1%20family | The Magnesium Transporter 1 (MagT1) Family (TC# 1.A.76) is a group of magnesium transporters that are part of the TOG superfamily. Goytain and Quamme identified a Mg2+-related transporter whose expression or function was affected by an implantation-associated protein precursor. They designated this protein, MagT1. MagT1 is expressed as a 335 amino acid polypeptide which includes five transmembrane helices. The nascent polypeptide possesses a cleavage site after the N-terminal signal sequence helix, rendering a mature MagT1 protein with four transmembrane helices. MagT1 additionally contains a number of phosphorylation sites.
Recent evidence demonstrates that the primary function of MagT1 is protein glycosylation, mediated by MagT1's function as a component of the oligosaccharyltransferase (OST).
Function
When expressed in Xenopus laevis oocytes, MagT1 mediates saturable Mg2+ uptake with a Km of 0.23 mM. Transport of Mg2+ by MagT1 is rheogenic, voltage-dependent, and does not display time-dependent inactivation. Transport is specific to Mg2+, as other divalent cations do not evoke currents. Large external concentrations of some cations inhibited Mg2+ transport (Ni2+, Zn2+, Mn2+) in MagT1-expressing oocytes although Ca2+and Fe2+ were without effect. MagT1 has an N-terminal thioredoxin domain of unknown function.
Zhou and Clapham identified two mammalian genes, MagT1 and TUSC3, catalyzing Mg2+ influx. MagT1 is universally expressed in all human tissues, and its expression level is upregulated in low extracellular Mg2+. Knockdown of either MagT1 or TUSC3 protein lowered the total and free intracellular Mg2+concentrations in mammalian cell lines. Morpholino knockdown of MagT1 and TUSC3 protein expression in zebrafish embryos resulted in early developmental arrest; excess Mg2+ or supplementation with mammalian mRNAs rescued these effects. Thus, MagT1 and TUSC3 are vertebrate plasma membrane Mg2+ transport system.
Transport reaction
The reaction catalyzed by MagT1, or a potential downstream glycosylation target (e.g. a Mg2+ transporter), is:
Mg2+ (out) → Mg2+ (in)
Role in magnesium deficiency
The identification of genetic changes and their functional consequences in patients with immunodeficiency resulting from loss of MAGT1 revealed that magnesium and MagT1 are key molecular players for T cell-mediated immune responses. This led to the description of XMEN (X-linked immunodeficiency with magnesium defect, Epstein-Barr Virus infection, and neoplasia) syndrome, for which Mg2+ supplementation has been shown to be beneficial. Similarly, the identification of copy-number variation leading to dysfunctional MAGT1 in a family with atypical ATR-X syndrome and skin abnormalities, suggested that the MAGT1 defect is responsible for the cutaneous problems.
Role in protein glycosylation
MagT1 and its homologue TUSC3 are both bona fide components of the oligosaccharyltransferase (OST).
References
Protein families
Membrane proteins
Transmembrane proteins
Transmembrane transporters
Transport proteins
Integral membrane proteins | Magnesium transporter1 family | [
"Biology"
] | 745 | [
"Protein families",
"Protein classification",
"Membrane proteins"
] |
51,456,649 | https://en.wikipedia.org/wiki/KX%20blood-group%20antigen%20family | The KX Blood-group Antigen (KXA) Family (TC# 2.A.112) consists of transport proteins that are part of the TOG superfamily. The KX gene codes for a novel protein with characteristics of membrane transporters that has been proposed to be a Na+ -dependent neutral amine and/or oligopeptide transporter. It is predicted to be 444 amino acyl residues in length and exhibits 10 putative transmembrane α-helical segments. The KX blood group antigen mRNA expression pattern correlates with McLeod syndrome.
Structure
Two covalently linked proteins, Kell and XK, constitute the Kell blood group system. Kell, a 93-Kd type II glycoprotein, is highly polymorphic and carries all but one of the known Kell antigens, and XK, which traverses the membrane ten times, carries a single antigen, the ubiquitous Kx.
Transport Reaction
The generalized reactions proposed to be catalyzed by KXA family members are:
1) Amino acid or peptide (out) → Amino acid or peptide (in)
2) Phospholipid (inner monolayer of the plasma membrane) → Phospholipid (outer monolayer of the plasma membrane)
McLeod Syndrome
The X-linked McLeod syndrome is defined by absent Kx red blood cell antigen and weak expression of Kell antigens. Most carriers of this McLeod blood group phenotype have acanthocytosis and elevated serum creatine kinase levels and are prone to develop a severe neurological disorder resembling Huntington's disease. Onset of neurological symptoms ranges between 25 and 60 years, and the penetrance of the disorder appears to be high. Additional symptoms of the McLeod neuroacanthocytosis syndrome that warrant therapeutic and diagnostic considerations include generalized seizures, neuromuscular symptoms leading to weakness and atrophy, and cardiopathy mainly manifesting with atrial fibrillation, malignant arrhythmias and dilated cardiomyopathy.
Apoptosis
A classic feature of apoptotic cells is the cell-surface exposure of phosphatidylserine (PtdSer) as an 'eat me' signal for engulfment. Suzuki et al. showed that the Xk-family protein Xkr8 mediates PtdSer exposure in response to apoptotic stimuli. Mouse Xkr8(-/-) cells or human cancer cells in which Xkr8 expression was repressed by hypermethylation failed to expose PtdSer during apoptosis and were inefficiently engulfed by phagocytes. Xkr8 was activated directly by caspases and required a caspase-3 cleavage site for its function. CED-8, the only Caenorhabditis elegans Xk-family homolog, also promoted apoptotic PtdSer exposure and cell-corpse engulfment. Thus, Xk-family proteins have evolutionarily conserved roles in promoting the phagocytosis of dying cells by altering the phospholipid distribution in the plasma membrane.
Chen et al. report that CED-8, a Caenorhabditis elegans protein implicated in controlling the kinetics of apoptosis and a homologue of the XK family proteins, is a substrate of the CED-3 caspase. Cleavage of CED-8 by CED-3 activates its proapoptotic function and generates a carboxyl-terminal cleavage product, acCED-8, that promotes PS externalization in apoptotic cells and can induce ectopic PS exposure in living cells. Consistent with its role in promoting PS externalization in apoptotic cells, ced-8 is important for cell corpse engulfment in C. elegans. Thus, there is a link between caspase activation and PS externalization, which triggers phagocytosis of apoptotic cells.
References
Protein families
Membrane proteins
Transmembrane proteins
Transmembrane transporters
Transport proteins
Integral membrane proteins | KX blood-group antigen family | [
"Biology"
] | 845 | [
"Protein families",
"Protein classification",
"Membrane proteins"
] |
51,456,706 | https://en.wikipedia.org/wiki/Isotropic%20beacon | An isotropic beacon is a hypothetical type of transmission beacon that emits a uniform EM signal in all directions for the purposes of communication with extraterrestrial intelligence.
Isotropic beacons and their relation to SETI
An isotropic beacon can be any transmitter that emits a uniform electromagnetic field. However, the term is most commonly used to describe a transmitter used by a civilization to call attention to itself over interstellar distances to extraterrestrial creatures. The isotropic beacon uses the Kardashev scale. The Kardashev scale is a method of measuring a civilization's level of technological advancement based on the amount of energy it is able to use. The measure was proposed by Soviet astronomer Nikolai Kardashev in 1964. The Kardashev scale has three designated categories, which are a Type I civilization, also called a planetary civilization, that can use and store all of the energy available on its planet. A Type II civilization, also called a stellar civilization, can use and control energy at the scale of its planetary system. A Type III civilization, also called a galactic civilization, can control energy at the scale of its entire host galaxy. Project Cyclops is and was one of the first looks at the theoretical framework of what it would take to create such a device.
References
Exploratory engineering
Hypothetical astronomical objects
Search for extraterrestrial intelligence
Astronomy projects
Hypothetical technology | Isotropic beacon | [
"Astronomy",
"Technology"
] | 286 | [
"Exploratory engineering",
"Astronomical hypotheses",
"Astrobiology stubs",
"Astronomical myths",
"Astronomy stubs",
"Hypothetical astronomical objects",
"Astronomy projects",
"Astronomical objects"
] |
41,398,498 | https://en.wikipedia.org/wiki/Filtered%20Rayleigh%20scattering | Filtered Rayleigh scattering (FRS) is a diagnostic technique which measures velocity, temperature, and pressure by determining Doppler shift, total intensity, and spectral line shape of laser induced Rayleigh-Brillouin scattering.
References
Scattering, absorption and radiative transfer (optics)
Visibility
Light | Filtered Rayleigh scattering | [
"Physics",
"Chemistry",
"Mathematics"
] | 60 | [
"Visibility",
"Physical phenomena",
" absorption and radiative transfer (optics)",
"Physical quantities",
"Spectrum (physical sciences)",
"Quantity",
"Scattering stubs",
"Electromagnetic spectrum",
"Waves",
"Scattering",
"Light",
"Wikipedia categories named after physical quantities"
] |
41,399,619 | https://en.wikipedia.org/wiki/LIA-UFSCar | The Advanced Interaction Laboratory (Portuguese: Laboratório de Interação Avançada) is a Human-Computer Interaction (HCI) research lab in the Department of Computer Science at UFSCar founded in 2003. Its mission is to research innovative information and communication technologies (ICTs) approaches for designing, developing, and using ICT aiming to overcome the challenges faced in the adoption of ICT considering social, professional, economical, political and cultural context of use.
One of LIA's main projects is Open Mind Common Sense in Brazil (OMCS-Br). The project started in 2005 in partnership with Media Lab from MIT. It is an approach for developing culture-sensitive interactive systems, which relies on using common sense knowledge for developing such systems. That is because individuals communicate with each other by assigning meaning to their messages based on their prior beliefs, attitudes, and values, i.e. based on their common sense. Previous researches developed at the Lab have shown that common sense expresses cultural knowledge. So, providing this kind of knowledge for computers is a way of allowing the development of culture-sensitive computer applications (Anacleto et al., 2006).
Main research areas:
Natural Interactions
Culture
Context Awareness
Social Networking
Education
Sensitive Design
Common Sense Reasoning
Games
Emotions
LIA researchers objectives are on research and development of new concepts and methodologies focused on multidisciplinary issues and the creation of open source tools geared to the promotion, development and sharing of knowledge through the adoption of ICTs.
Human–computer interaction | LIA-UFSCar | [
"Engineering"
] | 305 | [
"Human–computer interaction",
"Human–machine interaction"
] |
41,399,630 | https://en.wikipedia.org/wiki/Diversity%20panel | A diversity panel is a collection of genetic material or individual samples taken from a diverse population of a certain species. The idea is to illustrate the genetic and phenotypic diversity of the species.
Diversity panels exist for human populations, mouse and other organisms.
Researchers in the area of genetics often use diversity panels in order to reveal genotypes that are linked to certain traits, such as in QTL mapping with Genome-wide association study.
Those study analyze the Gene–environment interaction underneath simple and complex traits.
Examples
Human Genome Diversity Project
The Hybrid Mouse Diversity Panel
Maize NAM population (Nested association mapping)
Arabidopsis thaliana 1001 Genome project
See also
Genetics
Biodiversity
Evolution
References
Genetics | Diversity panel | [
"Biology"
] | 139 | [
"Genetics"
] |
41,399,688 | https://en.wikipedia.org/wiki/Identity%20in%20social%20insects | Eusocial insects have developed from their organization an ability to recognize one another within their society. This recognition of others, from recognizing individuals to groups, is an indication of society, and creates an identity colony wide for each insect.
Individuality thesis
Michael Ghiselin (1969, 1974) and David Hull (1976, 1978) asserted that complex or high level social insects are individuals rather than being like organisms. This claim originally related to the issues regards the nature and reality of species, but can be interpreted to relate to inter colonial developments. Within the colonies of social insects such as ants, dynamic social recognition systems make their advanced societies possible. The mediator for the social recognition systems included a blend of hydrocarbons that each individual within a colony carried as a way to recognize others from within the same colony. The individuality of the sole insect and the cohesion of the colony are very similar in the ways that they approach recognition and solve conflicts.
In the eusocial wasp Metapolybia cingulata, every individual fulfils a specific role in the colony in terms of nest building and for this reason the colony is able to thrive and actually have a nest. The roles have been categorized as: specialized water foragers, specialized pulp foragers, active builders, active generalists, and idle workers. If even one of these roles, even the "idle workers", did not accomplish their goal, the colony as a whole would be unsuccessful in maintaining a nest and would ultimately die.
Recognition through hydrocarbons
Some species of ants have evolved to have the ability to recognize other individuals from their colony to avoid aggression when met. The mechanics of this recognition are mediated by a mixture of specific signatures emanating from the individual, this mixture is a blend of hydrocarbons that emanate from the individual through the insects cuticles. The mixture of hydrocarbons is specific to the insect’s colony and is called the insect’s label. Upon one insect’s interaction with other insects, the perceived label is compared with its internal colony odor, the “template”. If the perceived label doesn't match the ingrained template then the encountered individual will be rejected.
The process of recognition by the individual is split into three components: production, perception, and action. The production factor includes the making of the label; in ants and other social insects the label is a signature mixture of long-chain hydrocarbons (cuticular hydrocarbons, CHCs). The perception factor involves the specific individual detecting the label on the other's cuticle and comparing what they perceive to their own innate template. A template-label differential is what is perceived and if that differential exceeds a certain point the ants will turn to aggression and if not they will accept or ignore the other individual.
Conflicts
Organisations built from individuals rather than cells face innate problems when it comes to reproduction. A collection of individuals that make up the colony result in a less-than-one relatedness which therefore causes conflict over the allocation of reproduction. The effects of these differences cost the whole colony as the colony must produce offspring that have genes suppressing the behaviors that allow conflict to arise.
References
Sociobiology | Identity in social insects | [
"Biology"
] | 644 | [
"Behavioural sciences",
"Behavior",
"Sociobiology"
] |
41,400,343 | https://en.wikipedia.org/wiki/Timeline%20of%20women%20in%20mathematics | This is a timeline of women in mathematics.
Timeline
Classical Age
Before 350: Pandrosion, a Greek mathematician known for an approximate solution to doubling the cube and a simplified exact solution to the construction of the geometric mean.
c. 350–370 until 415: The lifetime of Hypatia, a Greek Neoplatonist philosopher in Roman Egypt who was the first well-documented woman in mathematics.
18th Century
1748: Italian mathematician Maria Agnesi published the first book discussing both differential and integral calculus, called Instituzioni analitiche ad uso della gioventù italiana.
1759: French mathematician Émilie du Châtelet's translation and commentary on Isaac Newton’s work Principia Mathematica was published posthumously; it is still considered the standard French translation.
c. 1787 – 1797: Self-taught Chinese astronomer Wang Zhenyi published at least twelve books and multiple articles on astronomy and mathematics.
19th Century
1827: French mathematician Sophie Germain saw her theorem, known as Sophie Germain's theorem, published in a footnote of a book by the mathematician Adrien-Marie Legendre. In this theorem Germain proved that if x, y, and z are integers and if x5 + y5 = z5 then either x, y, or z must be divisible by 5. Germain's theorem was a major step toward proving Fermat's Last Theorem for the case where n equals 5.
1829: The first public examination of an American girl in geometry was held.
1858: Florence Nightingale became the first female member of the Royal Statistical Society.
1873: Sarah Woodhead of Britain became the first woman to take the Cambridge Mathematical Tripos Exam, which she passed.
1874: Russian mathematician Sofya Kovalevskaya became the first woman to earn a doctorate (in the modern sense) in mathematics.
1880: Charlotte Angas Scott of Britain obtained special permission to take the Cambridge Mathematical Tripos Exam, as women were not normally allowed to sit for the exam. She came eighth on the Tripos of all students taking them, but due to her sex, the title of "eighth wrangler," a high honour, went officially to a male student. At the ceremony, however, after the seventh wrangler had been announced, all the students in the audience shouted her name. Because she could not attend the award ceremony, Scott celebrated her accomplishment at Girton College where there were cheers and clapping at dinner, and a special evening ceremony where the students sang "See the Conquering Hero Comes", and she received an ode written by a staff member, and was crowned with laurels.
1885: Charlotte Angas Scott became the first British woman to receive a doctorate in mathematics, which she received from the University of London.
1886: Winifred Edgerton Merrill became the first American woman to earn a PhD in mathematics, which she earned from Columbia University.
1888: The Kovalevskaya top, one of a brief list of known examples of integrable rigid body motion, was discovered by Sofia Kovalevskaya.
1889: Sofia Kovalevskaya was appointed as the first female professor in Northern Europe, at the University of Stockholm.
1890: Philippa Fawcett of Britain became the first woman to obtain the top score in the Cambridge Mathematical Tripos Exam. Her score was 13 per cent higher than the second highest score. When the women's list was announced, Fawcett was described as "above the senior wrangler", but she did not receive the title of senior wrangler, as at that time only men could receive degrees and therefore only men were eligible for the Senior Wrangler title.
1891: Charlotte Angas Scott of Britain became the first woman to join the American Mathematical Society, then called the New York Mathematical Society.
1891: Cornelia Fabri of Italy became the first woman to earn a doctorate in math from the University of Pisa.
1894: Charlotte Angas Scott of Britain became the first woman on the first Council of the American Mathematical Society.
1897: Four women attended the inaugural International Congress of Mathematicians in Zurich in 1897 - Charlotte Angas Scott, Iginia Massarini, Vera von Schiff, and Charlotte Wedell.
20th Century
1911: Swedish mathematician Louise Petrén-Overton became the first woman in Sweden with a doctorate in mathematics.
1913: American mathematician Mildred Sanderson earned her PhD for a thesis that included an important theorem about modular invariants.
1918: German mathematician Emmy Noether published Noether's (first) theorem, which states that any differentiable symmetry of the action of a physical system has a corresponding conservation law.
1927: American mathematician Anna Pell-Wheeler became the first woman to present a lecture at the American Mathematical Society Colloquium.
1930: Cecilia Kreiger became the first woman to earn a PhD in mathematics in Canada, at the University of Toronto.
1930s: British mathematician Mary Cartwright proved her theorem, now known as Cartwright's theorem, which gives an estimate for the maximum modulus of an analytic function that takes the same value no more than p times in the unit disc. To prove the theorem she used a new approach, applying a technique introduced by Lars Ahlfors for conformal mappings.
1943: Euphemia Haynes became the first African-American woman to earn a Ph.D. in mathematics, which she earned from Catholic University of America.
1944: Helen Walker became the first female president of the American Statistical Association.
1949: American mathematician Gertrude Mary Cox became the first woman elected into the International Statistical Institute. Also, Maria Laura Lopes obtained her PhD in Mathematics, being the first woman to obtain the title in Brazil.
1951: Mary Cartwright of Britain became the first female president of the Mathematical Association.
1956: American mathematician Gladys West began collecting data from satellites at the Naval Surface Warfare Center Dahlgren Division. Her calculations directly impacted the development of accurate GPS systems.
1960s
1960 and 1966: British mathematician Lucy Joan Slater published two books about the hypergeometric functions from the Cambridge University Press.
1961: Mary Cartwright of Britain became the first woman to be President of the London Mathematical Society.
1962: American mathematician Mina Rees became the first person to receive the Award for Distinguished Service to Mathematics from the Mathematical Association of America.
1963: Grace Alele-Williams became the first Nigerian woman to earn a Ph.D when she defended her thesis in Mathematics Education at the University of Chicago (U.S.)
1964: Mary Cartwright of Britain became the first woman to be given the Sylvester Medal of the Royal Society.
1965: Scottish mathematician Elizabeth McHarg became the first female president of the Edinburgh Mathematical Society.
1966: American mathematician Mary L. Boas published Mathematical Methods in the Physical Sciences, which was still widely used in college classrooms as of 1999.
1968: Mary Cartwright of Britain became the first woman to be given the De Morgan Medal, the London Mathematical Society’s premier award.
1970s
1970: American mathematician Mina Rees became the first female president of the American Association for the Advancement of Science.
1971: American mathematician Mary Ellen Rudin constructed the first Dowker space.
1971: The Association for Women in Mathematics (AWM) was founded. It is a professional society whose mission is to encourage women and girls to study and to have active careers in the mathematical sciences, and to promote equal opportunity for and the equal treatment of women and girls in the mathematical sciences. It is incorporated in the state of Massachusetts.
1971: The American Mathematical Society established its Joint Committee on Women in the Mathematical Sciences (JCW), which later became a joint committee of multiple scholarly societies.
1973: American mathematician Jean Taylor published her dissertation on "Regularity of the Singular Set of Two-Dimensional Area-Minimizing Flat Chains Modulo 3 in R3" which solved a long-standing problem about length and smoothness of soap-film triple function curves.
1974: American mathematician Joan Birman published the book Braids, Links, and Mapping Class Groups. It has become a standard introduction, with many of today's researchers having learned the subject through it.
1975: American mathematician Julia Robinson became the first female mathematician elected to the National Academy of Sciences.
1975: Stella Cunliffe became the first female president of the Royal Statistical Society.
1976-1977: Marjorie Rice, an amateur American mathematician, discovered four new types of tessellating pentagons in 1976 and 1977.
1979: American mathematician Dorothy Lewis Bernstein became the first female president of the Mathematical Association of America.
1979: American mathematician Mary Ellen Rudin became the first woman to present the Mathematical Association of America’s Earle Raymond Hedrick Lectures, intended to showcase skilled expositors and enrich the understanding of instructors of college-level mathematics.
1980s
1981: Canadian-American mathematician Cathleen Morawetz became the first woman to give the Gibbs Lecture of the American Mathematical Society.
1981: American mathematician Doris Schattschneider became the first female editor of Mathematics Magazine, a refereed bimonthly publication of the Mathematical Association of America.
1982: Rebecca Walo Omana became the first female mathematics professor in the Democratic Republic of the Congo.
1983: American mathematician Julia Robinson was elected the first female president of the American Mathematical Society for the term of 1983-1984 (but was unable to complete her term as she was suffering from leukemia), and became the first female mathematician to be awarded a MacArthur Fellowship.
1986: European Women in Mathematics (EWM) was founded as an organization in 1986 by Bodil Branner, Caroline Series, Gudrun Kalmbach, Marie-Françoise Roy, and Dona Strauss, inspired by the activities of the Association for Women in Mathematics in the USA. It is the "first and best known" of several organizations devoted to women in mathematics in Europe.
1987: Eileen Poiani became the first female president of Pi Mu Epsilon.
1988: American mathematician Doris Schattschneider became the first woman to present the Mathematical Association of America’s J. Sutherland Frame Lectures.
1990s
1992: Australian mathematician Cheryl Praeger became the first female President of the Australian Mathematical Society.
1992: American mathematician Gloria Gilmer became the first woman to deliver a major National Association of Mathematicians lecture (it was the Cox-Talbot address).
1992: Ruth Hendry became the first woman to be officially named as the Senior Wrangler in the Cambridge University Mathematical Tripos examination.
1995: American mathematician Margaret Wright became the first female president of the Society for Industrial and Applied Mathematics.
1995: Israeli-Canadian mathematician Leah Edelstein-Keshet became the first female president of the Society for Mathematical Biology.
1995: Ina Kersten became the president of the German Mathematical Society, which meant she was the first woman to head the society.
1996: American mathematician Joan Birman became the first woman to receive the Mathematical Association of America’s Chauvenet Prize.
1996: Katherine Heinrich became the first female President of the Canadian Mathematical Society.
1996: Ioana Dumitriu, a New York University sophomore from Romania, became the first woman to be named a Putnam Fellow. Putnam Fellows are the top five (or six, in case of a tie) scorers on The William Lowell Putnam Mathematical Competition.
1998: Bodil Branner was the first woman to lead the Danish Mathematical Society, which she did from 1998 to 2002.
1998: Melanie Wood became the first female American to make the U.S. International Math Olympiad Team. She won silver medals in the 1998 and 1999 International Mathematical Olympiads.
21st Century
2000s
2002: Susan Howson became the first woman to be given the Adams Prize, given annually by the University of Cambridge to a British mathematician under the age of 40.
2002: Melanie Wood became the first American woman and second woman overall to be named a Putnam Fellow in 2002. Putnam Fellows are the top five (or six, in case of a tie) scorers on William Lowell Putnam Mathematical Competition.
2004: American Melanie Wood became the first woman to win the Frank and Brennie Morgan Prize for Outstanding Research in Mathematics by an Undergraduate Student. It is an annual award given to an undergraduate student in the US, Canada, or Mexico who demonstrates superior mathematics research.
2004: American Alison Miller became the first female gold medal winner on the U.S. International Mathematical Olympiad Team.
2006: Polish-Canadian mathematician Nicole Tomczak-Jaegermann became the first woman to win the CRM-Fields-PIMS prize.
2006: Stefanie Petermichl, a German mathematical analyst then at the University of Texas at Austin, became the first woman to win the Salem Prize, an annual award given to young mathematicians who have worked in Raphael Salem's field of interest, chiefly topics in analysis related to Fourier series. She shared the prize with Artur Avila.
2006: When Olga Gil Medrano became president of the Royal Spanish Mathematical Society in 2006, she was the first woman elected to that position.
2010s
2011: Belgian mathematician Ingrid Daubechies became the first female president of the International Mathematical Union.
2012: Latvian mathematician Daina Taimina became the first woman to win the Euler Book Prize, for her 2009 book Crocheting Adventures with Hyperbolic Planes.
2012: The Working Committee for Women in Mathematics, Chinese Mathematical Society (WCWM-CMS) was founded; it is a national non-profit academic organization in which female mathematicians who are engaged in research, teaching, and applications of mathematics can share their scientific research through academic exchanges both in China and abroad. It is one of the branches of the Chinese Mathematical Society (CMS).
2013: The African Women in Mathematics Association was founded. This professional organization with over 300 members promotes mathematics to African women and girls and supports female mathematicians.
2014: Maryam Mirzakhani became the first woman as well as the first Iranian to be awarded the Fields Medal, which she was awarded for "her outstanding contributions to the dynamics and geometry of Riemann surfaces and their moduli spaces." That year the Fields Medal was also awarded to Martin Hairer, Manjul Bhargava, and Artur Avila. It is a prize awarded to two, three, or four mathematicians not over 40 years of age at each International Congress of the International Mathematical Union, and is often viewed as the greatest honor a mathematician can receive.
2016: French mathematician Claire Voisin received the CNRS Gold medal, the highest scientific research award in France.
2016: The London Mathematical Society's Women in Mathematics Committee was awarded the Royal Society's inaugural Athena Prize.
2017: Nouzha El Yacoubi became the first female president of the African Mathematical Union.
2019: American mathematician Karen Uhlenbeck became the first woman to win the Abel Prize, with the award committee citing "the fundamental impact of her work on analysis, geometry and mathematical physics."
2019: Marissa Kawehi Loving became the first Native Hawaiian woman to earn a PhD in mathematics when she graduated from the University of Illinois Urbana-Champaign in 2019. In addition to being Native Hawaiian, she is also black, Japanese, and Puerto Rican.
2020s
2020: Lisa Piccirillo published a mathematical proof in the journal Annals of Mathematics determining that the Conway knot is not a smoothly slice knot, answering an unsolved problem in knot theory first proposed over fifty years prior by English mathematician John Horton Conway.
2020: Sarah B. Hart was appointed to be the Gresham Professor of Geometry in Gresham College, making her the first woman to hold this position "since the chair was established in 1597".
2022: Maryna Viazovska was awarded the Fields Medal in July 2022, making her the second woman (after Maryam Mirzakhani), the second person born in the Ukrainian SSR and the first with a degree from a Ukrainian university to ever receive it. That year the Fields Medal was also awarded to Hugo Duminil-Copin, June Huh, and James Maynard. The Fields Medal is a prize awarded to two, three, or four mathematicians not over 40 years of age at each International Congress of the International Mathematical Union, and is often viewed as the greatest honor a mathematician can receive.
2023: Ingrid Daubechies was awarded the Wolf Prize in Mathematics in February 2023, becoming the first woman to receive this award.
See also
List of women in mathematics
Timeline of mathematical innovation in South and West Asia
Timeline of mathematics
Timeline of women in mathematics in the United States
References
mathematics
Women | Timeline of women in mathematics | [
"Technology"
] | 3,335 | [
"Women in science and technology",
"Women in mathematics"
] |
41,400,608 | https://en.wikipedia.org/wiki/Bacopaside | Bacopasides are triterpene saponins isolated from Bacopa monnieri.
Members of this class of compounds include:
Bacopaside I, shows antidepressant-like effects in a mouse model
Bacopaside II
Bacopaside III
Bacopaside IV
Bacopaside V
Bacopaside VI
Bacopaside VII
Bacopaside VIII
Bacopaside IX
Bacopaside X
Bacopaside XI, shows nootropic activity in a mouse model
References
Saponins
Triterpene glycosides | Bacopaside | [
"Chemistry"
] | 122 | [
"Biomolecules by chemical classification",
"Natural products",
"Organic chemistry stubs",
"Organic compounds",
"Organic compound stubs",
"Saponins"
] |
41,400,804 | https://en.wikipedia.org/wiki/Fluridone | Fluridone is an organic compound that is used as aquatic herbicide often used to control invasive plants. It is used in the United States to control hydrilla and Eurasian watermilfoil among other species. Fluridone is sold as a solution and as a slow release solid because the herbicide level must be maintained for several weeks. The compound is a colorless solid.
The compound was first reported as a possible herbicide for cotton fields in 1976. It was registered with the U.S. Environmental Protection Agency in 1986 and has low toxicity to animals with no restrictions on swimming or drinking in treated water bodies. Fluridone breaks down in the environment over days or weeks with the major degradation product being N-methyl formamide. The half-life of fluridone in soils and sediments has been estimated at nine months. Fluridone degradation in soil and saturated sediment has been correlated with temperature and clay content, while fluridone degradation in water is largely dependent on UV light exposure. Fluridone transport through the soil, vadose zone, and aquifer is limited by its strong sorbance to organic matter.
Molecular target
Fluridone is a systemic herbicide that works by interfering with carotene formation which leads to chlorophyll degradation. Fluridone and are inhibitors of chloroplastic and cyanobacterial Phytoene desaturase, which in turn disrupts the carotenoid biosynthetic pathway.
Pharmaceutical
Fluridone's main action to disrupt photosynthesis in plants is by preventing the secretion of abscisic acid. As higher eukaryotes, such as humans, also rely on an abscisic acid pathway to create inflammation in normal physiological processes, fluridone could be investigated as being of interest in the development of anti-inflammatory agents.
Biodegradation
Fluridone degrades in soil and upon exposure to sunlight with a half-life of ≤21 days.
See also
Stormy Lake (Alaska), a lake that was treated with fluridone to remove invasive Elodea, an aquatic plant.
References
External links
EPA Substance Registry, entry for Fluridone
BREDA list of 1,5-Cis-Phytoene desaturase inhibitors
Herbicides
Trifluoromethyl compounds
Nonsteroidal anti-inflammatory drugs
4-Pyridones | Fluridone | [
"Biology"
] | 489 | [
"Herbicides",
"Biocides"
] |
41,401,019 | https://en.wikipedia.org/wiki/IEC%2062700 | IEC Technical Specification 62700: DC Power supply for notebook computer is an IEC specification of a common standard for external laptop computer AC adapters. Laptops and AC adapters following this standard will have interchangeable power supplies, which will enable easy reuse of used power supplies (thereby reducing electronic waste) and make buying a new compatible power supply for a laptop simpler.
The specification was published on 6 February 2014.
Alternatives
Despite being an industry open organization with open participation, the standard has been criticized by some for not being openly available for review. Some alternatives include:
IEEE has a proposed standard Universal Power Adapter for Mobile Devices for laptops and other devices.
The USB Promoters Group's USB Power Delivery ("PD") specification supports up to 240 W, and is intended to be able to power laptops.
The EmPower adapter was intended for charging laptops on passenger aircraft.
See also
Universal charger
USB Power Delivery Rev. 3.1 - includes Standard Power Range (SPR) mode with up to 100 W of power (20 V @ 4 A) and Extended Power Range (EPR) mode with up to 240 W of power (48 V @ 5 A)
Common external power supply - EN 62684 / IEC 62684, a widely adopted 2010 European specification standardizing smartphone power supplies on the USB Battery charging specification and USB connectors.
References
External links
IEC/TS 62700 ed1.0 - DC power supply for notebook computers at the IEC Webstore
IEC working groups for IEC 62700: Project Maintenance
Power supplies
62700
Electronics and the environment | IEC 62700 | [
"Technology"
] | 326 | [
"Computer standards",
"IEC standards"
] |
41,401,565 | https://en.wikipedia.org/wiki/Automotive%20Safety%20Integrity%20Level | Automotive Safety Integrity Level (ASIL) is a risk classification scheme defined by the ISO 26262 - Functional Safety for Road Vehicles standard. This is an adaptation of the Safety Integrity Level (SIL) used in IEC 61508 for the automotive industry. This classification helps defining the safety requirements necessary to be in line with the ISO 26262 standard. The ASIL is established by performing a risk analysis of a potential hazard by looking at the Severity, Exposure and Controllability of the vehicle operating scenario. The safety goal for that hazard in turn carries the ASIL requirements.
There are four ASILs identified by the standard: ASIL A, ASIL B, ASIL C, ASIL D. ASIL D dictates the highest integrity requirements on the product and ASIL A the lowest. Hazards that are identified as QM do not dictate any safety requirements.
Hazard Analysis and Risk Assessment
Because of the reference to SIL and because the ASIL incorporate 4 levels of hazard with a 5th non-hazardous level, it is common in descriptions of ASIL to compare its levels to the SIL levels and DO-178C Design Assurance Levels, respectively.
The determination of ASIL is the result of hazard analysis and risk assessment.
In the context of ISO 26262, a hazard is assessed based on the relative impact of hazardous effects related to a system, as adjusted for relative likelihoods of the hazard manifesting those effects. That is, each hazard is assessed in terms of severity of possible injuries within the context how much of the time a vehicle is exposed to the possibility of the hazard happening (refer ISO26262 definition of exposure) as well as the relative likelihood that a typical driver can act to prevent the injury (refer ISO26262 definitions of severity and controllability).
In short, ASIL refers both to risk and to risk-dependent requirements (standard minimal risk treatment for a given risk). Whereas risk may be generally expressed as
or
ASIL may be similarly expressed as
illustrating the role of Exposure and Controllability in establishing relative probability, which is combined with Severity to form an expression of risk.
Levels
The ASIL range from ASIL D, representing the highest degree of automotive hazard and highest degree of rigor applied in the assurance the resultant safety requirements, to QM, representing application with no automotive hazards and, therefore, no safety requirements to manage under the ISO 26262 safety processes. The intervening levels are simply a range of intermediate degrees of hazard and degrees of assurance required.
ASIL D
ASIL D, an abbreviation of Automotive Safety Integrity Level D, refers to the highest classification of initial hazard (injury risk) defined within ISO 26262 and to that standard's most stringent level of safety measures to apply for avoiding an unreasonable residual risk. In particular, ASIL D represents likely potential for severely life-threatening or fatal injury in the event of a malfunction and requires the highest level of assurance that the dependent safety goals are sufficient and have been achieved. An example of dangerous hazard that warrants the ASIL D level is loss of braking on all wheels.
ASIL D is noteworthy, not only because of the elevated risk it represents and the exceptional rigor required in development, but because automotive electrical, electronic, and software suppliers make claims that their products have been certified or otherwise accredited to ASIL D, ease development to ASIL D, or are otherwise suitable to or supportive of development of items to ASIL D. Any product able to comply with ASIL D requirements would also comply with any lower level.
ISO 26262 "highly recommends" the use of semi-formal modeling languages for ASIL D designs (Stateflow and SysML provide examples of such languages). Executable validation using either prototyping or simulation is mandatory.
ASIL C
Loss of braking for rear wheels only is less dangerous, this hazard is associated with ASIL C. Another example of a less critical function that warrants the ASIL C rating is cruise control.
For ASIL C designs the use of semi-formal modeling languages is highly recommended. Executable validation using either prototyping or simulation is mandatory.
ASIL B
ASIL B examples are headlights and brake lights.
Modeling of the ASIL B design can rely on an informal languages. This and other differences requirements make the cost difference between C and B to be the largest step across all the ASILs.
ASIL A
ASIL A is the lowest rating of the functional safety. A typical example are tail lights (non-braking). Less strict design walkthroughs can be used during the development (higher levels require more formal design inspections).
QM
Referring to "Quality Management", the QM level means that all assessed risks are tolerable from a safety perspective (even if the manufacturer might want to address them from a customer satisfaction perspective, for example make sure the vehicle starts). So, safety assurance controls are unnecessary and standard quality management processes are sufficient for development.
Decomposition
Designing an entire system to the rigorous standards of the higher levels of ASIL can be unwieldy, so ISO 26262 allows "decomposition": redundant subcomponents, each designed to a lower ASIL level, can be combined into a higher ASIL level design using higher-level methodologies. The subcomponents used in this way shall contain features that would allow higher-level integration. The frequently used notation for an ASIL X-level component that can be used as a part of an ASIL Y-level system is X(Y). For example, an A(B) component is designed at the ASIL A level of requirements, but is made to fit into ASIL B designs (this subcomponent is colloquially described as "B-ready"). ISO 26262 contains multiple examples of allowed decomposition scenarios, for example ASIL B = A(B) + A(B), i.e. two redundant B-ready ASIL A subcomponents can be combined into an ASIL B design. Headlights provide a natural example of such decomposition: there are at two of them, so they can be designed at ASIL A and combined into an ASIL B system as long as the combination is done properly (for example, it should not introduce a common point of failure).
Comparison with Other Hazard Level Standards
Given ASIL is a relatively recent development, discussions of ASIL often compare its levels to levels defined in other well-established safety or quality management systems. In particular, the ASIL are compared to the SIL risk reduction levels defined in IEC 61508 and the Design Assurance Levels used in the context of DO-178C and DO-254. While there are some similarities, it is important to also understand the differences.
IEC 61508 (SIL)
ISO 26262 is an extension of IEC 61508. IEC 61508 defines a widely referenced Safety Integrity Level (SIL) classification. Unlike other functional safety standards, ISO 26262 does not provide normative nor informative mapping of ASIL to SIL; while the two standards have similar processes for hazard assessment, ASIL and SIL are computed from different perspectives.
An ISO 26262 ASIL is a qualitative statement of assessed risk, assessed in terms of three risk parameters in a qualitative way that leaves room for interpretation.
On the other hand, the IEC 61508 SIL employ quantitative target probability or frequency measures of dangerous failures depending on the type of safety function.
In the context of IEC 61508, higher risk applications require greater robustness to dangerous failures:
That is, for a given Tolerable Risk, greater Risk requires more risk reduction, i.e., a smaller design target value for greater probability of dangerous failure. For a safety function operating in high demand or continuous mode of operation, SIL 1 is associated with a probability of dangerous failure limit of 10−5 per hour while SIL 4 is associated with a probability of dangerous failure rate limit of 10−9 per hour.
In commercial publications, ASIL D has been illustrated to align with SIL 3 and ASIL A is compared to SIL 1.
SAE ARP4761 and SAE ARP4754 (DAL)
While it is more common to compare the ISO 26262 Levels D through QM to the Design Assurance Levels (DAL) A through E and ascribe those levels to DO-178C; these DAL are actually defined and applied through the definitions of SAE ARP4761 and SAE ARP4754. Especially in terms of the management of vehicular hazards through a Safety Life Cycle, the scope of ISO 26262 is more comparable to the combined scope of SAE ARP4761 and SAE ARP4754. Functional Hazard Assessment (FHA) is defined in ARP4761 and the DAL are defined in ARP4754. DO-178C and DO-254 define the design assurance objectives that must be accomplished for given DAL.
Unlike SIL, it is the case that both ASIL and DAL are statements measuring degree of hazard. DAL E is the ARP4754 equivalent of QM; in both classifications hazards are negligible and safety management is not required. At the other end, DAL A and ASIL D represent the highest levels of risk addressed by the respective standards, but they do not address the same level of hazard. While ASIL D encompasses at most the hazards of a loaded passenger van, DAL A includes the greater hazards of large aircraft loaded with fuel and passengers. Publications might illustrate ASIL D as equivalent to either DAL B, to DAL A, or as an intermediate level.
Associated standards
ISO 26262
SAE J2980
See also
ASIL accuracy
ARP4761
ARP4754
DO-178C
DO-254
IEC 61508
References
Sources
Automotive engineering
Safety engineering
Automotive safety | Automotive Safety Integrity Level | [
"Engineering"
] | 2,028 | [
"Safety engineering",
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41,401,861 | https://en.wikipedia.org/wiki/AMSilk | AMSilk is an industrial supplier of synthetic silk biopolymers. The polymers are biocompatible and breathable. The company was founded in 2008 and has its headquarters at Campus Neuried in Munich. AMSilk is an industrial biotechnology company with a proprietary production process for their silk materials.
AMSilk produces a lightweight material trademarked as Biosteel, created from recombinant spider silk, which was used by Adidas to create a biodegradable running shoe. Jens Klein, former CEO of AMSilk, said during an interview that the biodegradable material can help reduce the amount of waste that has to be burned or pollutes the environment.
AMSilk is also developing breast implants made of biodegradable spider silk in collaboration with the German company Polytech.
History
AMSilk was founded in 2008 by Lin Römer and Professor Thomas Scheibel in Planegg, Germany, with the aim of becoming the world's first industrial supplier of synthetic silk biopolymers.
In 2011, the company partnered with the Fraunhofer Institute for Applied Polymer Research (IAP) to develop a new spin process for the AMSilk spider silk proteins.
In 2015, AMSilk began producing Biosteel® Fibre made from 100% silk proteins based on natural spider silk. Then, in November 2016, the company used its Biosteel® Fibre to collaborate with Adidas to create the ‘Futurecraft Biofabric’ shoe prototype. The Biosteel® Yarn fibre-based shoe is 100% biodegradable and is designed to replicate spider silk.
In April 2017, AMSilk announced its partnership with Gruschwitz Textilwerke.
In 2019, Swiss cosmetics manufacturer Givaudan acquired the cosmetics arm of AMSilk to expand the use of spider silk technology in cosmetic products.
In May 2021, the company secured a EUR 29 Million Series C fundraising. In April 2023 AMSilk raised an additional €25 million to accelerate industrial scale-up and expand commercial operations.
In February 2023, Evonik Industries signed a contract with AMSilk to supply industrial quantities of protein products made from the fermentation of renewable raw materials.
In 2023, AMSilk partnered with Brain Biotech, a company that develops and manufactures bio-based products for industry, to develop bio-based protein fibres for the textile industry.
Founding and Development
AMSilk has developed a range of vegan silk biopolymers designed for application in various medical devices, focusing on enhancing the bio-compatibility of medical implants.
In 2017, AMSilk was named one of the 50 most innovative companies in the world by the German edition of MIT Technology Review.
In 2018, AMSilk signed a deal with Airbus to develop a spider silk-based material for lightweight, high-performance planes. The collaboration aimed to launch the first prototype composite material in 2019.
Within the same year, the company partnered with Polytech Health & Aesthetics, the leading manufacturer of silicone implants, to begin a clinical trial of silk-coated implants on a handful of patients in Austria.
Headquarters
AMSilk is currently located at Campus Neuried in Munich, Germany, after relocating in October 2022.
Products and services
AMSilk partnered with Swiss watchmaker Omega SA in 2019 to make the Nato watch strap, which blends polyamide and Biosteel.
In January 2022, Mercedes-Benz partnered with AMSilk to develop sustainable door pulls using Biosteel fibre on its VISION EQXX concept electric car.
Since announcing its partnership with Airbus in 2018, AMSilk has worked on developing silk-reinforced polymers as a substitute for Carbon-fiber-reinforced polymers (CFRPs).
Environmental impact
AMSilk has worked with fashion brands to create sustainable alternatives using Biosteel® Fiber, a biosynthetic silk made by adding silk genes into bacteria through biofermentation. This material has been used in collaboration with Omega and Adidas for a watch strap and the "Futurecraft" shoe. AMSilk's Biosteel® Fiber, used in these collaborations is notable for its biodegradability, breaking down in seawater and on land within a few months.
Utilizing a bio-fabrication process that reprograms microorganisms based on spider DNA, the company produces this silk-like material at scale using bacteria and natural fermentation.
In November 2022, AMSilk participated as one of 100 renowned companies in the VISION 2045 Summit held alongside the United Nations Climate Change Conference (COP27).
References
External links
AMSilk Homepage
Materials science organizations
Natural materials
Polyamides
Silk
Spider anatomy | AMSilk | [
"Physics",
"Materials_science",
"Engineering"
] | 962 | [
"Natural materials",
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"Materials science organizations",
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41,402,520 | https://en.wikipedia.org/wiki/Lawrence%20Alexander%20Hardie | Lawrence Alexander Hardie (January 13, 1933 – December 17, 2013) was an American geologist, sedimentologist, and geochemist .
Hardie was a professor at Johns Hopkins University in the Department of Earth and Planetary Sciences. His research topics included evaporites, dolomitization, cyclical deposition of carbonate sediments, and plate tectonic driven changes in seawater chemistry. In the latter, he proposed that changes in the seafloor spreading rates at mid-ocean ridges have altered the composition of seawater throughout earth history, producing oscillations in the mineralogy of carbonate and evaporite precipitates. Specifically citing these scientific contributions, the Society for Sedimentary Geology (SEPM) awarded him the Francis J. Pettijohn Medal in 2003.
Early life and education
Hardie was born in Durban, Natal, South Africa, on January 13, 1933.
He attended the University of Natal, Durban, originally to pursue an undergraduate degree in chemistry. He focused instead on geology after attending lectures by South African geologist Lester Charles King. While a student, Hardie played soccer, and was selected as a member of the South African Universities "All Star" team four times. He earned a B.Sc. degree in Geology and Chemistry in 1955, and a B.Sc. (Hons.)degree in Geology in 1956.
In 1957, he was hired by King as an instructor and taught beginning classes in geology while working on his master's thesis on the origin of the Table Mountain Sandstone. He earned an M.Sc. in geology in 1959 under the guidance of Drs. Peter Matthews and Joseph Frankel.
In 1960, he was awarded a fellowship by the South African Council for Scientific and Industrial Research to spend an academic year in the U.S. He went to Johns Hopkins University and began working with sedimentologist Francis J. Pettijohn and geochemist Hans Eugster, in a newly built geochemistry laboratory.
There he conducted experimental work on evaporite minerals. He was offered a full-time graduate fellowship to earn a Ph.D. He briefly returned to South Africa to marry Glenys Kathleen Smith in Durban, and then graduated with a Ph.D. in 1965.
Academic career
Hardie joined the faculty at JHU as an assistant professor in the Department of Earth and Planetary Sciences in 1965. He later became a full professor, mentoring more than 30 graduate students. He also taught introductory geology to many undergraduate students, including his own children, introducing them to the intricacies of geological process through extensive field trips. He also served as the department chair from 1992 to 1995, and again in 2004–2006. He retired in 2007 to the status of professor emeritus.
Hardie ran the JHU field camp (Camp Singewald) in western Maryland for many summers in the 1960s and 1970s. He led regular field trips to the Florida Keys and Assateague Island, and also took students to the Bahamas and Baja California, Mexico. His work also took him frequently to the Dolomites in Italy, and he partook in long hikes and climbs. Some of his field work required travel by Zodiac inflatable boats, minibikes, and 3-wheeled all-terrain vehicles.
Scientific achievements
Early in his career, Hardie conducted research and experimentation with evaporites. Later he showed that the signal from evaporites provides evidence for seawater chemistry change. He observed that secular changes in the mineralogy of potash evaporites and ooids and cements in marine limestones are synchronous with greenhouse/hothouse climates and global sea level. Hardie's study of evaporites led to the hypothesis, since verified through study of seawater trapped inside crystals of marine halite, that seawater has undergone long-term variations in its major ion composition. He demonstrated that these variations are linked to plate tectonic processes at mid-ocean ridges. These studies improved the understanding of calcifying marine organisms and their role in the global carbon cycle, and also had implications for geochemistry, mineralogy, tectonics, biological evolution (biomineralization), oil/gas resources, and climate change. In recognition, he was awarded the Francis J. Pettijohn Medal for Excellence by the Society for Sedimentary Geology in 2003.
Hardie completed field research on the modern shallow marine carbonates of the Bahamas with Bob Ginsburg and others. In 1977 he wrote a book on comparative sedimentology entitled Sedimentation on the modern carbonate tidal flats of northwest Andros Island, Bahamas. He went on to study ancient carbonates of western Maryland (Cambro-Ordovician) and the Italian Dolomites (Triassic). Hardie's work on carbonates advanced the understanding of climate and sea level change, and the role of Milankovitch cycles in carbonate deposition.
Another of Hardie's contributions involves the study of the origins of dolomite, a mineral associated with the world's oil reserves. When dolomite replaces calcite minerals, its slightly smaller molar volume leaves voids in carbonate rock, causing oil migration. In the Italian Dolomites, Hardie (with student Edith Wilson) demonstrated the hydrothermal origin of dolomite in the Triassic Latemar buildup.
Hardie and his students and colleagues also studied cyclic sedimentation, confirming that platform carbonates of the Middle Triassic (Anisian-Ladinian) of the Latemar buildup consist of a vertical stack of over 500 thin (ave. thickness 0.6-0.85m) shallowing-upward depositional cycles that record high frequency eustatic sea level oscillations in tune to Milankovitch astronomical rhythms. They described the details of the cycles and deposition and created computer simulations that accurately modeled the Latemar cyclostratigraphy using Milankovitch-controlled sea level oscillations.
Awards and honors
Francis J. Pettijohn Medal for Sedimentology, from the Society for Sedimentary Geology, 2003.
Selected by the Student Council of Johns Hopkins University as one of the top ten teachers in the School of Arts & Sciences in 1998.
Oualline Distinguished Scholar at University of Texas, Austin, 1995.
The "Hardie Teaching Laboratory", in Olin Hall at JHU has been dedicated in 2014.
One of the annual Krieger School's Dean's Undergraduate Research Awards at JHU has been named after him, 2014.
The Lawrence A. Hardie Memorial Fund in Earth and Planetary Sciences at JHU, 2014.
Lawrence A. Hardie Commemorative Session, Geological Society of America meeting in Baltimore, MD, November 1–4, 2015.
Personal life and death
Hardie and his wife Glenys became U.S. citizens. They had two children; his daughter Deborah obtained a degree in mathematics at JHU, and Russell studied engineering at Loyola University Maryland. His son Russell is currently a professor in the department of Electrical and Computer Engineering at the University of Dayton.
Hardie enjoyed jazz and attended concerts at the Famous Ballroom in Baltimore. After moving from Baltimore to Pasadena, Maryland, in the 1970s, Hardie took to sailing on the Magothy River and the Chesapeake Bay. He taught his children and many of his students to sail. He later took up snow skiing and golf.
Hardie died at age 80 from complications of Alzheimer's disease on December 17, 2013, at the Community Hospital of the Monterey Peninsula in Monterey, California.
Selected publications
1960s
1970s
1980s
1990s
2000s
References
Johns Hopkins University faculty
American geochemists
Johns Hopkins University alumni
1933 births
2013 deaths
People from Durban
University of Natal alumni
South African geologists | Lawrence Alexander Hardie | [
"Chemistry"
] | 1,550 | [
"Geochemists",
"American geochemists"
] |
41,403,380 | https://en.wikipedia.org/wiki/Uniform%20Solar%20Energy%20and%20Hydronics%20Code | Designated as an American National Standard, the Uniform Solar, Hydronics and Geothermal Code (USHGC) is a model code developed by the International Association of Plumbing and Mechanical Officials (IAPMO) to govern the installation and inspection of solar energy, hydronic heating/cooling systems, and geothermal energy systems as a means of promoting the public's health, safety and welfare.
The USHGC is developed using the American National Standards Institute's consensus development procedures. This process brings together volunteers representing a variety of viewpoints and interests to achieve consensus on solar energy, hydronic heating/cooling systems, and geothermal energy practices.
History
Recognizing the necessity for a solar energy code to be adopted by jurisdictions as a means of regulating such systems, IAPMO passed a resolution at its 1975 annual business conference to form a technical committee for the development of such a document.
After several months of work, this committee, composed of individuals representing industry, public utility companies, inspectors, plumbers, and engineers, completed the Uniform Solar Energy Code's (USEC) first edition and in September 1976 this document was adopted by IAPMO.
In December 2011, the Radiant Professionals Alliance joined IAPMO and soon after work began to incorporate hydronic heating/cooling provisions into the USEC to be released in 2015 as the Uniform Solar Energy and Hydronics Code (USEHC).
2018 Edition
Though geothermal energy is not new in the 2018 edition, the title for the 2018 edition was revised to clarify that the code also pertains to geothermal energy systems. The 2018 Uniform Solar, Hydronics and Geothermal Code (USHGC) represents the most current approaches in the solar energy, hydronics and geothermal field.
Content
Chapter 1 - Administration
Chapter 2 - Definitions
Chapter 3 - General Regulations
Chapter 4 - Hydronics
Chapter 5 - Solar Thermal Systems
Chapter 6 - Thermal Storage
Chapter 7 - Geothermal Energy Systems
Chapter 8 - Duct Systems
Chapter 9 - Solar Photovoltaic Systems
Chapter 10 - Referenced Standards
Appendix A - Engineered Solar Energy Systems
Appendix B - Solar Photovoltaic System Installation Guidelines
Appendix C - Supplemental Checklist for Solar Photovoltaic Systems
See also
IAPMO
IAPMO Standards
IAPMO R&T
Thermal energy storage
Uniform Codes
Uniform Plumbing Code
Uniform Mechanical Code
Uniform Swimming Pool, Spa and Hot Tub Code
Building officials
Building inspection
External links
Uniform Solar, Hydronics & Geothermal Code Website
References
1975 Uniform Solar Energy Code Resolution
1976 Uniform Solar Energy Code Advertisement
1976 IAPMO Conference Wrap
1976 San Gabriel Valley Tribune Reprint
First USEC Technical Committee
RPA Membership Ratifies Move to IAPMO
IAPMO Seeking Technical Committee Members
Safety codes
Plumbing | Uniform Solar Energy and Hydronics Code | [
"Engineering"
] | 544 | [
"Construction",
"Plumbing"
] |
41,403,497 | https://en.wikipedia.org/wiki/Sex%20differences%20in%20memory | Although there are many physiological and psychological gender differences in humans, memory, in general, is fairly stable across the sexes. By studying the specific instances in which males and females demonstrate differences in memory, we are able to further understand the brain structures and functions associated with memory.
It is within specific experimental trials that differences appear, such as methods of recalling past events, explicit facial emotion recognition tasks, and neuroimaging studies regarding size and activation of different brain regions. Research seems to focus especially on gender differences in explicit memory. Like many other nuances of the human psyche, these differences are studied with the goal of lending insight to a greater understanding of the human brain.
History of research
Perceptions of gender differences in cognitive abilities date back to ancient Greece, when the early physician Hippocrates dubbed the term 'hysteria' or 'wandering womb' to account for emotional instability and mental illness in women. This diagnosis survived up until the mid-19th century and the beginning of the women's suffrage movement, and was used as evidence for women's inability to handle intellectual work. Prominent physicians of this era, including neurologist Sigmund Freud, argued that women were biologically suited to homemaking and housework, as they did not have enough blood to power both the brain and the uterus. When women began attending university in the late 19th and early 20th centuries, opponents asserted that the high demands of post-secondary education on the female brain would render women sterile.
The mass entrance of women into the workplace during World War I to replace the conscripted men fighting overseas, provided a turning point for views on women's cognitive abilities. Having demonstrated that they were capable of functioning in the workplace, women gained the right to vote in post-war United States, Canada, and the United Kingdom. Though women were able to vote and hold paid employment, they were still not regarded as intellectually equal to men. The development of the encephalization quotient by Harry Jerison in 1973 seemed to confirm popular beliefs and about women's cognitive abilities; this quotient was one of the first means of indirectly measuring brain size, and it demonstrated that women have, on average, smaller brain areas than men.
Specific areas of memory
The results from research on sex differences in memory are mixed and inconsistent, as some studies show no difference, and others show a female or male advantage.
Short-term memory
Women have consistently demonstrated a stronger short-term memory than men on tests. This is supported by data that gauges learning ability in terms of word lists and the development of strategies that improve the ability to learn new things and impede interference; however, there is also data that indicates that men are better at short-term memory tasks than women when visual stimuli is a factor, but this research lacks consistency.
Autobiographical memory
Memory loss
Research suggests that there may be gendered differences in rates of memory decline. While research on the subject has not always been consistent, it's clear that men and women experience significantly different rates of memory decline throughout their life.
It was once decided that the difference in memory decline between genders was due to the typically longer lifespan of a woman, however, this has since been disproven. The difference between the lifespan of a male and female is not great enough to explain the additional onset of memory decline from disease that woman experience.
Alzheimer's disease
As men and women age, dementia become more likely to manifest. Dementia has been reported to affect up to 5% of people over the age of 65. Of the different types of dementia, Alzheimer's disease is the most common, accounting for up to 65% of dementia cases. Research into the disease is ongoing, but there appears to be evidence supporting the claim that Alzheimer's manifests differently between the sexes. There is also evidence that Alzheimer's disease is more common in women than in men.
Multiple studies have found that there is a significant difference in the symptoms of Alzheimer's disease that affect the sexes. Some of these behavioral and psychological symptoms of dementia (BPSD) include depression, anxiety, dysphoria, nighttime disturbances, and aggression. Several recent studies have found that women tend to exhibit symptoms such as depression and anxiety more often than men. One study has even gone as far as to suggest that having depression at any point during midlife increases chances of Alzheimer's Disease developing later by up to 70%. Men, on the other hand, exhibit symptoms such as aggression and other socially inappropriate behaviors more often. In addition, it has been found that men are more likely to have coronary artery disease which has been known to damage the blood brain barrier (BBB) by causing micro vascular lesions. Damage to the blood brain barrier seems to be connected to cognitive decline and several forms of dementia, including Alzheimer's Disease. Women with Alzheimer's disease also have more serious cognitive impairments in many indicators compared to men. Also, a number of studies of people with Alzheimer's disease have found a greater brain or cognitive reserve in men.
Another contributing factor to differences in Alzheimer's progression between the sexes may be socioeconomic status (SES). Men, historically, have had better opportunities to obtain an education and increase their SES. In recent years, women are being afforded many of the same opportunities, which may explain why there appears to be a decrease of instances of dementia in women related to SES factors.
References
Cognitive psychology
Sex differences in psychology | Sex differences in memory | [
"Biology"
] | 1,106 | [
"Behavioural sciences",
"Behavior",
"Cognitive psychology"
] |
41,404,279 | https://en.wikipedia.org/wiki/Timothy%20M.%20P.%20Tait | Timothy Maurice Paul Tait (born May 29, 1971) is a Canadian-American particle physicist known for his contributions to the theoretical physics and particle physics, particularly in the field of dark matter. He is currently a professor in the Department of Physics and Astronomy at the University of California, Irvine.
Early life and education
Tait was born on May 29, 1971, in Owen Sound, Canada. He received his Bachelor of Science degree from the University of California, San Diego, and his Ph.D. in Physics from Michigan State University, where he worked under the supervision of Chien-Peng Yuan.
Career
After completing his doctoral studies, Tait worked as a postdoctoral researcher at Argonne National Lab and the Fermi National Accelerator Laboratory. In 2007, Tait joined the faculty of the Department of Physics and Astronomy at Northwestern University, and in 2009 moved to the University of California, Irvine. He currently has the title of Chancellor's Professor, and has also served as the chair of the department from 2019 to 2023.
Tait's research focuses on particle physics, cosmology, and the search for dark matter. He has proposed that dark matter may be ordinary matter confined to hidden dimensions, a theory that has received significant attention in the field.
In 2013, Tait was elected a Fellow of the American Physical Society for his contributions to the phenomenology of theories of dark matter.
Publications
Tait's scientific publications can be found on the INSPIRE-HEP Literature Database
Tait's opinion article discussing the use of comparisons in recommendation letters within academia .
Article on slate.com about the current status of the field of particle physics .
Honors and awards
In addition to his fellowship in the American Physical Society, Tait has received several other honors and awards throughout his career. In 2016 he was named Friedrich Wilhelm Bessel Fellow by Alexander von Humboldt Foundation, in 2017 he served as Van der Waals Professor at the University of Amsterdam, and in 2019 he received the Mentorship Award by the Division of Particles and Fields of the American Physical Society and the Distinguished Mid-Career Faculty Award for Research from UC Irvine.
Tait has an Erdös Number of 4.
References
External links
Tait's webpage at UC Irvine
Popular Science Lectures by Tait concerning the Search for the Higgs Boson
Lectures by Tait concerning the Future of Particle Physics after the Higgs Discovery
New Scientist Article "Higgs in space: Orbiting telescope could beat the LHC"
Public lecture by Tait about Dark Matter
Theoretical physicists
Particle physicists
21st-century American physicists
University of California, Irvine faculty
Fellows of the American Physical Society
Living people
1971 births | Timothy M. P. Tait | [
"Physics"
] | 535 | [
"Theoretical physics",
"Particle physicists",
"Particle physics",
"Theoretical physicists"
] |
41,404,633 | https://en.wikipedia.org/wiki/Magnesium%20monoperoxyphthalate | Magnesium monoperoxyphthalate (MMPP) is a water-soluble peroxy acid used as an oxidant in organic synthesis. Its main areas of use are the conversion of ketones to esters (Baeyer-Villiger oxidation), epoxidation of alkenes (Prilezhaev reaction), oxidation of sulfides to sulfoxides and sulfones, oxidation of amines to produce amine oxides, and in the oxidative cleavage of hydrazones.
Due to its insolubility in non-polar solvents MMPP has seen less use than the more widely used meta-chloroperoxybenzoic acid (mCPBA). Although work up procedures are more simply handled in polar solvents, usage of MMPP to oxidize nonpolar substrates in biphasic media combined with a phase transfer catalyst have been inefficient. Despite this MMPP has certain advantages over mCPBA including a lower cost of production and increased stability.
MMPP is also used as the active ingredient in certain surface disinfectants such as Dismozon Pur. As a surface disinfectant MMPP exhibits a broad spectrum biocidal effect including inactivation of endospores. Its wide surface compatibility enables its use on sensitive materials, such as plastic and rubber equipment used in hospitals. Additionally MMPP has been investigated as a potential antibacterial agent for mouthwashes and toothpaste.
References
Benzene derivatives
Disinfectants
Oxidizing agents
Organic peroxy acids
Reagents for organic chemistry
Magnesium compounds | Magnesium monoperoxyphthalate | [
"Chemistry"
] | 337 | [
"Redox",
"Oxidizing agents",
"Reagents for organic chemistry"
] |
41,405,104 | https://en.wikipedia.org/wiki/Torus%20action | In algebraic geometry, a torus action on an algebraic variety is a group action of an algebraic torus on the variety. A variety equipped with an action of a torus T is called a T-variety. In differential geometry, one considers an action of a real or complex torus on a manifold (or an orbifold).
A normal algebraic variety with a torus acting on it in such a way that there is a dense orbit is called a toric variety (for example, orbit closures that are normal are toric varieties).
Linear action of a torus
A linear action of a torus can be simultaneously diagonalized, after extending the base field if necessary: if a torus T is acting on a finite-dimensional vector space V, then there is a direct sum decomposition:
where
is a group homomorphism, a character of T.
, T-invariant subspace called the weight subspace of weight .
The decomposition exists because the linear action determines (and is determined by) a linear representation and then consists of commuting diagonalizable linear transformations, upon extending the base field.
If V does not have finite dimension, the existence of such a decomposition is tricky but one easy case when decomposition is possible is when V is a union of finite-dimensional representations ( is called rational; see below for an example). Alternatively, one uses functional analysis; for example, uses a Hilbert-space direct sum.
Example: Let be a polynomial ring over an infinite field k. Let act on it as algebra automorphisms by: for
where
= integers.
Then each is a T-weight vector and so a monomial is a T-weight vector of weight . Hence,
Note if for all i, then this is the usual decomposition of the polynomial ring into homogeneous components.
Białynicki-Birula decomposition
The Białynicki-Birula decomposition says that a smooth projective algebraic T-variety admits a T-stable cellular decomposition.
It is often described as algebraic Morse theory.
See also
Sumihiro's theorem
GKM variety
Equivariant cohomology
monomial ideal
References
A. Bialynicki-Birula, "Some Theorems on Actions of Algebraic Groups," Annals of Mathematics, Second Series, Vol. 98, No. 3 (Nov., 1973), pp. 480–497
M. Brion, C. Procesi, Action d'un tore dans une variété projective, in Operator algebras, unitary representations, and invariant theory (Paris 1989), Prog. in Math. 92 (1990), 509–539.
Algebraic geometry
Algebraic groups | Torus action | [
"Mathematics"
] | 548 | [
"Fields of abstract algebra",
"Algebraic geometry",
"Geometry",
"Geometry stubs"
] |
41,405,317 | https://en.wikipedia.org/wiki/Institute%20for%20Biodiversity%20and%20Environmental%20Research | The Institute for Biodiversity and Environmental Research (IBER; ; Jawi: اينستيتوت ڤڽليديقن بيوديۏرسيتي دان عالم سکيتر) in Brunei Darussalam (Borneo/Southeast Asia) is a research institute of Universiti Brunei Darussalam (UBD) dedicated to biodiversity and environmental sciences research and education. IBER's location within the northwest Borneo hotspot offers unique opportunities for long-term studies in both terrestrial and marine tropical ecosystems.
History
Biodiversity and environment have been the university's research strengths since its founding in 1985. This was further developed through the Brunei Rainforest Project, a collaborative project between UBD and the Royal Geographical Society (RGS) in the establishment of a permanent field research facility in the Ulu Temburong National Park - the Kuala Belalong Field Studies Centre (KBFSC) where a 14-month scientific expedition was carried out in 1991–1992. Since then, KBFSC has gained local and international recognition as a centre for tropical rainforest research and education in Borneo.
UBD has participated in and led several expeditions to forest areas within the Heart of Borneo (HoB) boundary including the Sarawak Forestry Department expeditions to Lanjak Entimau and Paya Maga, the UBD-led biodiversity surveys to Sungai Ingei Conservation Forest and the iCUBE Scientific Expedition to Bukit Pagon, Brunei Darussalam.
Following these significant milestones achieved in the biodiversity and environment research frontier, IBER was established in 2013 to further develop and expand prospects and international collaborations in biodiversity explorations within Brunei. The Institute's establishment was officially announced by Sultan Hassanal Bolkiah at UBD's 25th convocation ceremony on 12 September 2013.
Scope
IBER was set up as a focal agency within UBD that functions to coordinate, facilitate, support and execute research, education and outreach activities or programmes within the biodiversity and environmental scope (both terrestrial and marine). KBFSC, previously an independent research centre of UBD, is now managed as the premier international research and educational facility for IBER and remains as a core research focus of UBD.
Research
Brunei Darussalam is one of the top ten forested nations in the world, and is situated in the hyperdiverse northwest Borneo tropical forests and the edge of the Coral Triangle. Recognising Brunei's strengths and prominence in biodiversity, the university has biodiversity and environmental studies as one of its five key research areas.
Biodiversity and environmental research at the institute is conducted through university- and government-funded research projects, as well as international. A major initiative of the institute is the establishment of the International Consortium of Universities for the study of Biodiversity and the Environment (iCUBE). This group brings together a core group of research universities (King's College London, Korea University, Monash University, National University of Singapore, Universiti Brunei Darussalam, University of Auckland, University of Bonn, and University of North Carolina at Chapel Hill) united in a shared goal of research and education on biodiversity and the environment.
The institute has a network of 1 ha permanent forest plots located throughout Brunei Darussalam. Set up in the early 1990s, five plots are located in lowland Mixed Dipterocarp Forests in the Belait and Tutong districts and at KBFSC, and two heath (Kerangas) forest plots are located in the Belait district. The institute also manages a series of nine 0.25 ha plots at three altitudinal ranges at KBFSC. In 2007, the University, in collaboration with the Center for Tropical Forest Science of Harvard University, commenced the establishment of the 25 ha UBD-CTFS Plot at KBFSC.
Education and outreach
KBFSC is the core facility for educational activities organised by IBER. Since its inception, KBFSC has served as a venue for various education programmes, field courses and field based workshops participated by undergraduate and high school students. Themes encompass tropical rainforest biodiversity and ecology, emergent issues of biodiversity conservation, sustainability and climate change.
‘Friends of Belalong’ is an outreach programme embarked by KBFSC and is currently adopted by IBER. It is a volunteer programme aimed at promoting biodiversity and environmental awareness and instilling the values of conservation among the public. The programme welcomes local and international volunteers.
References
External links
Universiti Brunei Darussalam official website
Institute for Biodiversity and Environmental Research official webpage
Scientific organizations established in 1985
Environmental research
1985 establishments in Brunei
Universiti Brunei Darussalam | Institute for Biodiversity and Environmental Research | [
"Environmental_science"
] | 943 | [
"Environmental research"
] |
41,405,384 | https://en.wikipedia.org/wiki/Throwing | Throwing is a physical action that consists of mechanically accelerating a projectile and then releasing it into a ballistic trajectory, usually with the aim of impacting a distant target. Throwing typically refers to hand-throwing by animals with prehensile forelimbs, in which the projectile is grasped in a hand and the proximal limb segments move through compounded kinematic chains to impart a mechanical advantaged swinging motion. For other animals, the definition of throwing is somewhat unclear, as other actions such as spitting or spraying may or may not be included.
Primates are the most proliferative throwers in the animal kingdom, and they typically throw feces as a form of agonistic behavior. Of all primates, humans are by far the most capable throwers, and throw a large variety of projectiles with a much greater complexity, efficacy and accuracy. Throughout human evolution, humans (especially Homo sapiens) have used hand-thrown projectiles for hunting and in warfare — first through rock-throwing, then refined weapon-throwing (e.g. spear, axe or dart), and into modern day with payload-carrying devices such as hand grenades, flashbangs and tear gas canisters.
To overcome the biophysical limitations of throwing by hand, humans also designed tools to improve the efficiency of their throwing techniques. The atlatl, amentum, sling and various models of catapults are notable examples of throwing mechanisms.
With the advent of the bow and arrow, and later the gunpowder-based firearm, human innovation into throwing tools as weapons essentially halted, but throwing either by hand or with tools has persisted for recreational purposes (such as thrower tools in fishing and clay pigeon shooting) or as a form of exercise. Throwing is thus still performed in many sports and games, particularly ball games. In throwing sports (especially track and field) throwing is the main determiner of the outcome.
Evolutionary history
Throwing dates back two million years to Homo erectus.
Development of the offensive throwing of projectiles is mostly a development of the human lineage, although the aimed throwing of sticks and rocks by male chimpanzees during agonistic displays has been observed, first described by Jane Goodall in 1964.
"Accumulative throwing", that is, the targeted throwing of rocks at a specific target, leading to the gradual accumulation of a stone pile, has also been described for chimpanzees.
Wooden darts were used for hunting at least from the Middle Paleolithic, by Homo heidelbergensis. The spear-thrower is a development of the Upper Paleolithic, certainly in use by the Solutrean (c. 20,000 years ago).
Human athletes can achieve throwing speeds close to , far in excess of the maximal speed attainable by chimpanzees, at about . This ability reflects the ability of the human shoulder muscles and tendons to store elasticity until it is needed to propel an object.
Types
Types of throws include overhand throws, underhand throws and using both hands. Overhand throws are thrown predominantly above the shoulder, underhand throws below. Overhand throws are usually significantly faster, and ball speeds of have been recorded in baseball. Thrown objects can often be intentionally spun for stability or aerodynamic effects.
The notion of throwing typically refers to an action performed without mechanical assistance, but mechanical assistance, as long as it does not involve the release of chemical or electric energy, does not fundamentally change the nature of the action, and can thus be considered as throwing too. As such, throwing mechanisms will be discussed in this section.
Overhand throwing motion
The overhand throwing motion is a complex motor skill that involves the entire body in a series of linked movements starting from the legs, progressing up through the pelvis and trunk, and culminating in a ballistic motion in the arm that propels a projectile forward. It is used almost exclusively in athletic events. The throwing motion can be broken down into three basic steps: cocking, accelerating, and releasing.
Desired qualities in the action produce a fast, accurate throw. These qualities are affected by the physical attributes of the thrower like height, strength, and flexibility. However it is mainly the throwing motion mechanics and the thrower's ability to coordinate them that determines the quality of the throw. Determining the desired qualities of the throwing motion is difficult to assess due to the extremely short amount of time that it takes professionals to perform the motion.
Throwing mechanisms
Throwing mechanisms, along with projectiles themselves, rank amongst the oldest technological artefacts in the archaeological records. They vary greatly in size and complexity, from the hand-held and extremely simple sling, to the very heavy and complex catapults. These two types of devices have in common with hand-throwing the fact that the only requirements for their projectiles are size and weight. In that sense they differ from more specialized throwing techniques such as those developed in archery, where the projectiles have very strong requirements for their shape.
Uses
Thrown weapons
Throwing is used for propelling weapons such as stones or spears at enemies, predators, or prey.
Knife throwing, the art of throwing a knife at a target
Spear throwing was used and until relatively recent times was the predominant mode of weaponry used in warfare
Throwing axes are thrown, usually overhand
Boomerangs (throwing sticks) are used by Aboriginals for hunting purposes.
Shurikenjutsu are traditional Japanese thrown weapons
Hand grenades are thrown explosives
Sports and games
Pitching or bowling in bat-and-ball games, e.g. cricket, baseball, softball
Throwing of balls and clubs is used in juggling
Bowling
Darts
Flying disc games
Stone skipping
Track and field contains four major throwing events: discus throw, hammer throw, javelin throw and shot put. The weight throw is the fifth most common field throwing event, while the club throw is unique to disability athletics.
Distant exchange and disposal of artifacts
Throwing can be performed in a non-agonistic way, when the target is a cooperating agent who will perform a somewhat opposite action called catch. Humans are most likely the only animals capable of throwing with such an intent. This is an almost exclusively intraspecific behavior, whose goal is to exchange artifacts without having to shorten the distance between the participants. The seemingly unique exception to this intraspecificity is when humans play a game called fetch with a domestic dog, although in that situation the dog always catches, never throws.
Such use is so common that it is a common metaphor for figuratively sending something to someone (e.g. to throw a bone).
An other very common use of the behavior is for disposal. The employed term is then typically throwing away, and it too is very commonly used figuratively.
Sexual differences
Studies differ as to the degree of sexual dimorphism in throwing amongst modern humans.
Research by MythBusters found that men and women throw almost equally well with their non-dominant hand, suggesting that the sexual differences were probably due to differences in training.
Other research suggests there exist innate biological differences between the sexes that lead to disparities in throwing efficiency, with males better adapted at delivering more effective throws than females.
Non-primates
Throwing is rare among non-primates but, provided the definition is relaxed to entail for instance spitting, several examples can be found amongst various taxa, such as camelids, cobras or the archerfish.
Elephants have been observed throwing rocks and logs, using their trunk to grab and flick items, although they lack the accuracy that primates can achieve, and it is more commonly used as a warning to aggressors.
If one is willing to consider dropping as a special case of throwing, then one can include birds, most notably vultures, as some species are known to drop stones in order to break shells or other hard food sources on the ground.
Orcas are often observed throwing seals in the air, usually by hitting them with their caudal fin. This behavior is speculated to be purely recreational.
See also
Catch (game)
References
External links
Ballistics
Motor skills
Biomechanics
Paleoanthropology
Articles containing video clips | Throwing | [
"Physics",
"Biology"
] | 1,643 | [
"Biomechanics",
"Behavior",
"Applied and interdisciplinary physics",
"Motor skills",
"Motor control",
"Mechanics",
"Ballistics"
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41,406,085 | https://en.wikipedia.org/wiki/Potter%20Valley%20Project | The Potter Valley Project is an interbasin water transfer project in Northern California in the United States, delivering water from the Eel River basin to turbines in the headwaters of the Russian River. The project is owned and operated by Pacific Gas and Electric Company (PG&E). The main facilities are two dams on the Eel River, a diversion tunnel and hydroelectric plant. Average annual throughput is , although this figure varies significantly with both the amount of precipitation in the Eel River basin and the demand on the Russian River.
In 2019, PG&E chose not to relicense the hydroelectric project with the Federal Energy Regulatory Commission, as it had become unprofitable to operate. Federal regulations require that PG&E submit a final license surrender application by 2025, which would enable it to begin decommissioning the project. The dams and hydroelectric facilities are to be removed, while various options are being considered for maintaining water diversions to the Russian River.
History
Construction on the project began in 1900, when The Eel River Power and Irrigation Company (later the Snow Mountain Water and Power Company) constructed the Cape Horn Dam and a one-mile (1.6 km), -diameter tunnel under the drainage divide to Potter Valley, at the headwaters of the East Fork Russian River. The water dropped to a powerhouse before being released to the East Fork Russian River. On April 1, 1908, the first deliveries were made and power production began with a capacity of 4000 kilowatts (KW). In 1910, the generation capacity was boosted to 7000 KW and in 1912 second penstock was built to increase the flow capacity of the tunnel. The powerhouse was upgraded to 9400 KW in 1917, after the addition of a fourth unit.
Initially, the project could only operate during the winter months, when there was enough water in the Eel River to divert without drying up the riverbed downstream. In 1920, Snow Mountain Water and Power began construction on a larger dam on the Eel River, upstream from Cape Horn. Scott Dam, which forms Lake Pillsbury, was completed in 1922. With its greater storage capacity, it provides water for the diversion during the summer months and also affords some flood control during winter storms. In 1930, ownership of the project was transferred to PG&E. In 1959, Coyote Valley Dam was built on the Russian River as part of the separate Russian River Basin Project (RRBP), forming Lake Mendocino, which provides additional storage of diverted Eel River waters. This reservoir serves a critical function during dry years as it is drawn down to compensate for reduced diversions from the Eel River system.
The Federal Energy Regulatory Commission relicensing of the project on January 28, 2004, placed limits on the amount of water that can be diverted. In combination with drought conditions, diversions between 2004 and 2009 averaged , or 57% of the historical average. Since then, late summer water has been released from Cape Horn Dam at rates roughly mimicking or exceeding natural flows in an attempt to mitigate the impacts to fisheries.
Operations
The project derives water from a drainage basin of above Scott Dam and approximately between Scott Dam and Cape Horn Dam, where water is diverted to the Russian River. The vast majority of the water arrives as winter rain between December and April, with a smaller, less reliable amount furnished by snowmelt and groundwater through June. Scott Dam, which forms Lake Pillsbury, has a total storage capacity of . Project regulations require that the gates at Scott Dam be opened between October 16 and April 1, for safety reasons during the winter months. Winter storms fill the reservoir, which provides only very limited flood control, because the average annual runoff of is over five times the project storage capacity. It is not uncommon for the dams to spill eight or nine times during a single winter season. After the wet season passes, Lake Pillsbury is drawn down beginning April 1. Typical summer drawdowns leave the reservoir at or above , or 27 percent capacity. Water is released to Cape Horn Dam, which diverts the majority, while releasing a small flow to the Eel River designed to mimic natural summer flows. This is typically around , but can decrease significantly during dry years.
Beneficiaries
In 1924, the Potter Valley Irrigation District (PVID) was formed to provide irrigation water to the farmers along the East Branch Russian River. The district currently serves 390 farmers with rights to of project water per year, for the irrigation of within a district boundary of . Because there is very little natural runoff in Potter Valley and the local geology is non-conducive to groundwater storage, the PVID is the only constituent that depends solely on Eel River water.
Project water also serves farmers and municipalities downstream along the Russian River, in Mendocino County. The total water use per year is about . Even further downstream, water users in Sonoma County use between per year. These users depend both on Potter Valley Project water and natural flows in the Russian River basin managed by the RRBP. In addition to agricultural, domestic and industrial uses, project water helps to maintain a minimum dry season flow of in the Russian River, serving for recreational, aesthetic and fishery enhancement purposes. Project water is estimated to provide at least part of the water supply for nearly 500,000 people living in Sonoma and Mendocino Counties, mainly in the North Bay area, for cities such as Santa Rosa.
Environmental impact
The Potter Valley Project has had a significant impact on summer low streamflows in the Eel River basin. Although the project taps water from only the upper 10% of the Eel River system, this headwaters region provides most of the summer flow in the lower Eel, especially during critically dry years, when only are allowed into the Eel River past the Cape Horn diversion point. As a result, summer-run salmon and steelhead in the Eel River are negatively affected during dry years. In addition, while Cape Horn Dam has a fish ladder, the larger Scott Dam blocks fish migration to about of habitat in the Eel River headwaters.
See also
Water in California
References
Water supply infrastructure in California
Interbasin transfer
Hydroelectric power plants in California
Geography of Mendocino County, California
Geography of Sonoma County, California
Eel River (California)
Russian River (California) | Potter Valley Project | [
"Environmental_science"
] | 1,258 | [
"Hydrology",
"Interbasin transfer"
] |
41,406,443 | https://en.wikipedia.org/wiki/Michiaki%20Takahashi | was a Japanese virologist, best known for inventing the first chickenpox vaccine. He developed the "Oka" vaccine by producing v-Oka, a live-attenuated virus strain of varicella zoster virus.
Life
Born at Higashisumiyoshi-ku, Osaka, Japan, on February 17, 1928, Takahashi earned his MD in 1954 from Osaka University's Medical School, and completed in 1959 the Graduate Course of Medical Science, majoring in poxvirus virology.
Between 1963 and 1965 he studied at Baylor College of Medicine in Texas, and at the Fels Research Institute of Temple University, in Philadelphia.
The experience of watching his eldest son, Teruyuki, suffer from chickenpox while studying in the U.S. led him to begin development of a chickenpox vaccine in 1971. The research was extremely difficult, but was completed in 1973.
In 1984, the vaccine was certified by the WHO as the most suitable chickenpox vaccine, and in 1986, the Japanese Ministry of Health and Welfare approved it for practical use in countries around the world.
Takahashi became the director of Osaka University's Microbial Disease Study Group in 1994.
After retirement from Osaka University, he was given the title professor emeritus.
He died on December 16, 2013, from heart failure.
Awards
Saburo Kojima Memorial Culture Award (1975)
VZVRF's third Scientific Achievement Award (1997)
Prince Mahidol Award (2008)
Legacy
The Japanese Society for Vaccinology presents an annual prize named in Takahashi's honor: The Japanese Society for Vaccinology Takahashi Prize, founded in October 2005.
On 17 February 2022, Takahashi was honoured with a Google Doodle on his 94th birthday.
References
External links
First Person: ‘I created the vaccine for chickenpox’
NYTimes obituary
1928 births
2013 deaths
Japanese virologists
20th-century Japanese biologists
21st-century Japanese scientists
Vaccinologists
Osaka University alumni
Baylor College of Medicine alumni
Temple University alumni
Academic staff of Osaka University
People from Higashisumiyoshi, Osaka
People from Osaka
People from Osaka Prefecture | Michiaki Takahashi | [
"Biology"
] | 434 | [
"Vaccination",
"Vaccinologists"
] |
59,234,246 | https://en.wikipedia.org/wiki/Wilhelm%20Klemm | Wilhelm Karl Klemm (5 January 1896 – 24 October 1985) was an inorganic and physical chemist.
Klemm did extensive work on intermetallic compounds, rare earth metals, transition elements and compounds involving oxygen and fluorine.
He and Heinrich Bommer were the first to isolate elemental erbium (1934) and ytterbium (1936).
Klemm refined Eduard Zintl's ideas about the structure of intermetallic compounds and their connections to develop the Zintl-Klemm concept.
Klemm co-authored one of the ten most-cited papers in the history of the journal Zeitschrift für anorganische und allgemeine Chemie.
His textbooks on inorganic chemistry became standard works for chemists. His Magnetochemie (c1936) is considered foundational to magnetochemistry. Anorganische Chemie (Inorganic Chemistry) by Klemm and Rudolf Hoppe has been described as a legendary work by two titans of solid state chemistry.
Klemm was the second President of the Gesellschaft Deutscher Chemiker (GDCh), serving from 1952 to 1953.
He was President of the International Union of Pure and Applied Chemistry (IUPAC) from 1965 to 1967. Klemm co-edited the journal Zeitschrift für anorganische und allgemeine Chemie from 1939 to 1965.
Since 1985, the GDCh has awarded the Wilhelm Klemm Prize in his honor.
Education
Klemm was born on 5 January 1896 in Guhrau, Lower Silesia to Wilhelm and Ottilie (John) Klemm. His father was a master carpenter and furniture manufacturer.
Klemm attended the Realgymnasium in Grünberg before serving in the German army from 1914 to 1919. He was an army liaison in Turkey, where he learned Turkish and Arabic.
From 1919 to 1923 Klemm studied chemistry at University of Breslau. In 1923, Klemm received a doctor of philosophy degree. Heinrich Biltz supervised Klemm's dissertation on the chemistry of uric acid, entitled Aus der Chemie der Harnsäure (1923).
In December 1924 Klemm married Lisabeth Herrmann, who had studied chemistry at Danzig (Gdansk) and at Breslau University with Heinrich Biltz. She received her degree in 1921, completing a doctoral thesis magna cum laude on the methylation of uric acid and its methyl derivatives. Her father was a forestry scientist. The Klemms formed a community of which Lisbeth Klemm was the social center, and Wilhelm was the intellectual center.
Heinrich Biltz recommended Klemm to his brother Wilhelm Biltz, who had begun teaching at the Technische Hochschule Hannover in 1921.
Klemm habilitated there in the field of inorganic chemistry in 1927.
Career
Technische Universität Hannover
From 1927 to 1929 Klemm worked as a Privatdozent at the Technische Hochschule Hannover. In 1929 he was promoted to the position of associate professor.
Düsseldorf
Klemm was reportedly a Professor for inorganic chemistry in Düsseldorf at some time between 1929 and 1933.
Technische Hochschule Danzig
As of 1 April 1933, Klemm became a full professor and head of the Department of Inorganic Chemistry at the Technische Hochschule Danzig. Klemm replaced Hans Joachim von Wartenberg, who had taught at the Technische Hochschule Danzig from 1913 to 1932 and served in several senior positions including head of the Department of Inorganic Chemistry. Von Wartenberg left in August 1932 to become director of the Institute of Inorganic Chemistry at the University of Göttingen.
The Technische Hochschule Danzig was at that time located in the Free City of Danzig (1920-1939). The population of the city was predominantly German and faculty and staff tended to align with National Socialism even before 1933. The attitudes of scientists at the university have been described in terms of "shades of gray".
Klemm had some involvement with the National Socialists but his motives are not known.
Klemm was not a signatory of the Bekenntnis der Professoren an den deutschen Universitäten (1933).
He did sign the later Aufstellung zu den Unterzeichnern des Appells „An die Gebildeten der Welt“ (11. November 1933), a list of academics who professed support for Adolf Hitler and National Socialism. Klemm became a member of the NSDAP (Nazi Party) in 1938, rather later than contemporaries like Adolf Butenandt.
Following the Invasion of Poland which began 1 September 1939, the Free City of Danzig was annexed by Germany, and anti-Jewish measures escalated.
In a letter to the editorial staff of Chemische Berichte in June 1942 Klemm argued that contributions from chemist Georg-Maria Schwab and other "non-Aryan" authors should not appear in German chemical journals.
Klemm served as head of the Inorganic Chemistry department of the Technische Hochschule Danzig from 1933 to 1945, and was its last vice-rector. He was responsible for the evacuation of equipment, books, files, and people in 1944–1945, in advance of Soviet troops. Approximately 500 books and pieces of equipment and 300 staff and family members sailed on the ship Deutschland on 27 January 1945 bound for Kiel.
Much of the university including the chemistry building was destroyed in subsequent months. Following the war Gdańsk became part of Poland. On 24 March 1945, the university was re-established as a Polish institution.
Christian-Albrechts-Universität zu Kiel
During the period of denazification following the war, Nazi party members and others who were more than nominal participants in Nazi activities were barred from public posts. Those applying for academic positions had to certify their acceptability.
Klemm was the lead author for the preparation and publication of the six inorganic chemistry volumes of the FIAT review of German science, 1939-1946 (1948-1949). FIAT volumes were compiled by leading German scientists in cooperation with the Military Government for Germany, involving Field Information Agencies Technical from the British, French, and U.S. zones, to report on the scientific work done in Germany during the war years.
From 23 May 1947 to 1951, Klemm led the Inorganic Chemical Institute at University of Kiel (Christian-Albrechts-Universität zu Kiel). The Institute of Inorganic Chemistry at the University of Kiel has a collection of correspondence and other papers dating from 1947 through the 1960s, relating to Wilhelm Klemm and his successor, Robert Juza.
Klemm's first wife, Lisabeth Klemm (née Herrmann, born 9 October 1895, Eberswalde) died of cancer on 15 October 1948 in Kiel.
In 1949, Klemm married Lina Arndt, a dentist who had been a friend of his first wife.
Westfälische Wilhelms-Universität Münster
By 1951, the Allied Powers were lifting reemployment restrictions against Nazi party members, and it became easier for academics to find or change positions.
Klemm accepted a position as professor and department head at the Westfälische Wilhelms-Universität Münster where he remained from 1951 until he retired as professor emeritus in 1964. The university was in need of substantial rebuilding after the war. Klemm headed the Institute of Inorganic and Analytical Chemistry. As rector of the Westfälische Wilhelms-Universität Münster from 1957 to 1958, Klemm founded its Natural Science Center.
He also served as vice-rector from 1958 to 1960.
Scientific contributions
Klemm's scientific work focused on the systematic investigation of solids, to understand the properties of substances and how they related to the substances' atomic arrangement.
At a very early stage he recognized the importance of physical methods including crystal structure analysis using X-ray diffraction and magnetochemical measurements for the investigation of solids. His paper with Wilhelm Biltz, "Über die Elektrolytische Leitfähigkeit geschmolzenen Scandiumchlorids"(About the electrolytic conductivity of molten scandium chloride, 1923) became one of the ten most-cited papers in the history of the journal Zeitschrift für anorganische und allgemeine Chemie.
Klemm has been described as the founder of modern magnetochemistry for introducing new methods in the 1920s and describing them in detail in his 1936 book, Magnetochemie. It is considered a "pioneering textbook" and the foundation of much subsequent work in the field.
Klemm's areas of focus included the intermetallic compounds, rare earth metals, transition elements and compounds involving oxygen and fluorine.
His work on the properties of rare elements such as gallium, germanium, indium, rhenium and related compounds was considered authoritative. He was particularly interested in the synthesis of compounds involving unusual degrees of oxidation, and the comparison of compounds with similar structure in order to better understand their properties.
Klemm studied molar volumes and coefficients of expansion of both fused and solid halides. He also examined indium, gallium, germanium, and rhenium, and rare earth elements, determining their heats of formation and studying their reactivity with ammonia.
In 1936, Wilhelm Klemm and Anna Neuber published research on the magnetic properties of triphenylchromium compounds. Their magnetic susceptibility (approx. 1.73 Bohr magnetons) was found to be inconsistent with the structure determination proposed by Franz Hein for penta-, tetra- and triphenylchromium compounds.
In 1934, Wilhelm Klemm and Heinrich Bommer were the first to achieve pure erbium, by heating erbium chloride with potassium.
In 1936, Wilhelm Klemm and Heinrich Bommer were the first to isolate elemental ytterbium by reducing ytterbium (III) chloride with potassium at 250 °C. They also determined the crystal structure and magnetic properties of the metal.
Klemm's work on transition metal oxides, fluorides and lanthanides was interrupted in 1939 by World War II.
Klemm's research led to the identification of systematic relationships among the elements of the periodic system. It also led to a new method for classifying rare earths based on the stability of both completely filled and "half-filled" electrons which could be applied to both ions and metals.
Klemm identified unusual oxidation states in oxo- and fluoro- complexes and refined the ideas of Eduard Zintl on the structure of intermetallic compounds to develop the Zintl-Klemm concept.
One of Klemm's students and coworkers was Rudolf Hoppe. Hoppe worked with Klemm on fluorides, and in 1962 produced the first noble gas compounds.
Textbooks
Over the course of his career, Klemm wrote and co-wrote a number of textbooks on inorganic chemistry which became standard textbooks in the field, repeatedly reprinted and translated. These include:
Klemm, Wilhelm, Anorganische chemie (c1935). Berlin, Leipzig, W. de Gruyter & co.
Klemm, Wilhelm, Magnetochemie (c1936) Leipzig, Akademische Verlagsgesellschaft m.b.H. Considered a foundational text in magnetochemistry.
Biltz, Heinrich, Klemm, Wilhelm and Fischer, Werner. Experimentelle Einführung in die anorganische Chemie (1937), Berlin, Leipzig, Walter de Gruyter & Co. An introduction to inorganic chemistry using experimental methods. Beginning with the 21st edition in 1937, Heinrich Biltz was joined by co-authors Wilhelm Klemm and Werner Fischer. Their new version of the textbook became so well known that it was referred to as "BKF". At least 73 editions were published.
Klemm, Wilhelm, and Hoppe, Rudolf. Anorganische Chemie (c1979). Berlin; Boston : De Gruyter, c1979. Anorganische Chemie by Klemm and Rudolf Hoppe has been described as a legendary work by two titans of solid state chemistry.
Organizational contributions
Klemm was a member of the Academy of Sciences Leopoldina (Deutsche Akademie der Naturforscher Leopoldina) in Halle, Germany; the Bavarian Academy of Sciences and Humanities (Bayerische Akademie der Wissenschaften) in Munich, Germany;
the Göttingen Academy of Sciences (Akademie der Wissenschaften zu Göttingen) in Göttingen, Germany; and
the Rhine-Westphalian Academy of Sciences in Düsseldorf, Germany.
Klemm was co-editor of Zeitschrift für anorganische und allgemeine Chemie (the journal for inorganic and general chemistry) from 1939 to 1965.
From 1945 onwards, his central tasks were to reestablish teaching and research in Kiel (1947-1951) and in Münster (1951-) and to help reconstruct chemical institutions at the national and international levels.
Wilhelm Klemm was an influential science organizer. He became the second president of the Gesellschaft Deutscher Chemiker (1952-1953), working to foster communication between chemists in different zones of post-war Germany.
In the 1950s and 1960s, he worked to build communication and cohesion between scientists in the GDR and the Federal Republic.
As president of the GDCh he participated in the founding of the Chemical Society of the GDR, formally created on 11 May 1953.
Wilhelm Klemm campaigned for international exchange in the sciences. From 1965 to 1967 he was President of the International Union of Pure and Applied Chemistry (IUPAC).
He was the first German scientist to fill such a high international position after World War II.
In 1966 he became the secretary-treasurer of the recently formed Committee on Data for Science and Technology (CODATA) of the International Council of Scientific Unions (ICSU), whose purpose was to encourage the use of international standards of scientific nomenclature, symbols, constants, and data sets. He served on the committee from 1968 to 1975, also holding the position of vice-president.
Philanthropy
On 8 July 1977 Wilhelm and Lina Klemm signed a will describing their intention to use the revenue from the eventual sale of their home at Theresiengrund 22 for scholarships for students to travel and present their research internationally.
Lina Klemm died on 4 April 1985.
Wilhelm Klemm died on 24 October 1985 while visiting Gdansk for the first time since the war, to receive commemorative medal no. 467 from the Gdańsk University of Technology. His body was returned to Münster, where he is buried in the Münster Central Cemetery, ID 186397208.
The first scholarships of the Wilhelm-Klemm-Stiftung were awarded in 1987.
Awards and honors
1951, Liebig Medal (Liebig-Denkmünze), Gesellschaft Deutscher Chemiker (Society of German Chemists)
1953, Moissan-Médaille, École nationale supérieure de chimie de Paris
1958, Centenary Prize, Royal Society of Chemistry
1963, Carl-Duisberg-Plakette, Gesellschaft Deutscher Chemiker, "In recognition of his successful cooperation in German and international organizations, through which he has made a decisive contribution to the reputation of German chemistry abroad".
1965, Lavoisier Medal, Société Chimique de France
1966, Großes Verdienstkreuz/Commander's Cross of the Order of Merit of the Federal Republic of Germany
1980, Festschrift, The Journal of the Less-Common Metals published an issue in honor of his 85th birthday, which occurred on 5 January 1981.
1981, title of Honourable Senator, University of Münster, in recognition of contributions to the rebuilding of the university.
honorary doctorates from the Polytechnic in Darmstadt, University of Bordeaux, University of Dijon, University of Lille
Wilhelm-Klemm-Straße in Münster is named in Klemm's honor. It is part of the university and is the site of the Physics building.
1985, first award of the Wilhelm Klemm Prize, given by the GDCh in his honor.
1995, first award of the Maria Skłodowska-Curie and Wilhelm Klemm Lectureship Award, a collaborative initiative of the Polish and German Chemical Societies to give invited joint lectures.
Additional sources
Bibliography:
Goubeau, Josef. (1961) "Wilhelm Klemm." In Zeitschrift für Elektrochemie. Berichte der Bunsengesellschaft für Physikalische Chemie. 65, p. 105.
King RB 2004, 'The metallurgist's periodic table and the Zintl-Klemm concept', in DH Rouvray DH & RB King (eds), The periodic table: into the 21st century, Institute of Physics Publishing, Philadelphia, , pp. 189–206.
Miller GJ, Schmidt MW, Wang F & You T-S 2011, 'Quantitative Advances in the Zintl-Klemm Formalism,' in TF Fässler (ed), Zintl Phases: Principles and Recent Developments, Springer-Verlag, Berlin, pp. 1 56,
Klemm W 1950, 'Einige probleme aus der physik und der chemie der halbmetalle und der metametalle', Angewandte Chemie, vol. 62, no. 6, pp. 133–42
References
1896 births
1985 deaths
People from Góra
Scientists from the Province of Silesia
20th-century German chemists
University of Breslau alumni
Academic staff of the University of Kiel
Commanders Crosses of the Order of Merit of the Federal Republic of Germany
Rare earth scientists
Presidents of the German Chemical Society
Solid state chemists | Wilhelm Klemm | [
"Chemistry"
] | 3,702 | [
"Solid state chemists"
] |
59,237,500 | https://en.wikipedia.org/wiki/Simon%20Devitt | Simon John Devitt (born 17 July 1981) is an Australian theoretical quantum physicist who has worked on large-scale Quantum computing architectures, Quantum network systems design, Quantum programming development and Quantum error correction. In 2022 he was appointed as a member to Australia's National Quantum Advisory Committee.
Education
Devitt received his BSc (Hons) in Physics from Melbourne University in 2004. He completed his PhD in physics under Lloyd Hollenberg at the Center for Quantum Computation (CQCT) at the University of Melbourne in 2008, with a thesis entitled Quantum information engineering: concepts to quantum technologies. During his Ph.D, Devitt was awarded the Rae and Edith Bennett Travelling Scholarship at the Faculty of Mathematics, University of Cambridge, where he worked within the Centre for Quantum Computation, headed by Artur Ekert.
Career and research
Following his PhD, Devitt did postdoctoral research at the Japanese National Institute of Informatics in the group of Kae Nemoto, where he was promoted to assistant professor in 2011. Later, in 2014, he took a position of associate professor in physics at Ochanomizu University at the Leading Graduate School Promotion Center. In 2015 he took up a position as senior research scientist at the Japanese National Laboratories, Riken, in the Superconducting Quantum Simulation Research Team, headed by Jaw-Shen Tsai.
In 2017, he returned to Australia where he was appointed research fellow for the Australian Research Council Center of Excellence for Engineered Quantum Systems (EQUS) at Macquarie University and in 2018 he was appointed as lecturer in quantum architectures at the Center for Quantum Software and Information (QSI) at the University of Technology Sydney. In 2020 he was awarded the inaugural Warren prize by the Royal Society of New South Wales for his service to quantum computing development and in 2021 he was elected fellow of the Royal Society of New South Wales and the Australian Institute of Physics. In 2022 Devitt was appointed associate professor and research director of the Center for quantum software and information at UTS.
Devitt's research has focused on the design of practical large-scale systems architectures for quantum computing and communications system. He published the first architecture, in an atom-optical system, that utilised techniques in topological quantum error correction that could be conceptually scaled to an arbitrary number of encoded qubits. In 2014, in collaboration with NTT Communications and TU Wien, he developed a design for a scalable system using the Nitrogen-vacancy center and in 2017 he developed a large-scale system design for Ion trap quantum computing in collaboration with the University of Sussex. Devitt has also worked in the development of scalable Quantum networks, developing designs for what is now known as 2nd and 3rd generation quantum repeaters and inventing, with scientists in Japan and Australia, a quantum version of Sneakernets.
Devitt's recent work has focused largely on developing a software framework for large-scale, error-corrected machines, including methods to map high-level quantum circuits to machine level instructions and how these error-corrected circuits need to be optimised to reduce the resource load on quantum computing hardware.
In 2016, he established, with Jared Cole of RMIT University, the first consultancy specialising in quantum technology, which became a founding member of the Spanish based industry group, the Quantum World Association (QWA).
He has worked with and advised several companies and government agencies worldwide on quantum technology development, is regularly featured in the popular press, and comments for outlets such as New Scientist and MIT Technology Review on developments in quantum technology research.
In 2016, Devitt created and hosts the Meet the meQuanics podcast, where scientists, industry leaders and students discuss issues related to the new quantum technology sector.
Selected publications
20 June 2013
.
20 June 2016
.
20 September 2016
.
1 February 2017
.
7 December 2012
.
References
External links
Simon Devitt: Home page. Faculty of Engineering and IT, University of Technology, Sydney.
h-bar: Quantum Consultants..
1981 births
Living people
Scientists from Adelaide
Academic staff of the University of Technology Sydney
University of Melbourne alumni
Academic staff of Ochanomizu University
Quantum physicists
21st-century Australian physicists
Theoretical physicists | Simon Devitt | [
"Physics"
] | 841 | [
"Theoretical physics",
"Quantum physicists",
"Theoretical physicists",
"Quantum mechanics"
] |
59,238,157 | https://en.wikipedia.org/wiki/Sacoproteus | Sacoproteus is a genus of sea slugs in the Limapontiidae family, described in 2018. It contains five species, of which four were newly described when the genus was erected, and one (Sacoproteus smaragdinus) was reassigned from its previous classification of Stiliger smaragdinus as the type species of the new genus. Most of the species are mimetic of toxic "sea-grape" algae in the genus Caulerpa.
Species
The species of the genus were found to closely mimic the appearance of different types of toxic algae that they feed on.
Sacoproteus smaragdinus (previously classified as Stiliger smaragdinus): mimics Caulerpa racemosa and Caulerpa lentilifera
Sacoproteus nishae: mimics Caulerpa chemnitzia
Sacoproteus yhiae: mimics Caulerpa cactoides and Caulerpa gemminata
Sacoproteus browni: probably as S. yhiae
Sacoproteus thomasleei: not mimetic
References
Limapontiidae
Mimicry | Sacoproteus | [
"Biology"
] | 241 | [
"Mimicry",
"Biological defense mechanisms"
] |
59,242,945 | https://en.wikipedia.org/wiki/Operation%20Northern%20Shield | Operation Northern Shield () was an Israeli military operation that took place from 4 December 2018 until 13 January 2019. The operation's declared goal was to locate and destroy Hezbollah tunnels that cross the Blue Line from Lebanon into northern Israel. According to Israel, this operation is part of the ongoing Iran–Israel proxy conflict. On 17 December 2018, United Nations Interim Force in Lebanon (UNIFIL) acknowledged the existence of four tunnels near the Israel–Lebanon border and confirmed that two of them cross the Blue Line in violation of United Nations Security Council Resolution 1701, which helped end the 2006 Lebanon War.
Background
The Israel Defense Forces (IDF) started searching for Hezbollah tunnels into Israel in 2013 after residents of northern Israel reported hearing sounds of digging, but failed to find anything. After the 2014 Gaza War, which saw numerous tunnels dug by Hamas from the Gaza Strip into Israel being uncovered and being utilized in several attacks, the IDF renewed its search for Hezbollah tunnels in northern Israel, and this time found indications that such tunnels existed. A laboratory made up of soldiers from technology and intelligence units was formed to investigate it, based on a similar laboratory investigating Hamas tunnels in southern Israel. A variety of seismic sensors and radar systems were used to locate the tunnels.
The operation was planned two and a half years in advance. After realizing that Hezbollah's tunnels would need to be dealt with in 2015, a team of IDF military engineers, intelligence officers, and technology experts determined that plans should be made for destroying the tunnels. Preparations were made in secrecy, with many participants told they were participating in routine training. Senior officers in the IDF Combat Engineering Corps realized that the hard, rocky terrain of northern Israel, as opposed to the soft, sandy terrain of the area where Hamas tunnels were dug in the south, would pose a challenge that the IDF was not accustomed to. In 2017, it was decided to send 11 Engineering Corps personnel to Europe to learn about hard-rock excavation.
According to a senior Israeli official, the operation was launched in December 2018 due to fears that the details of the planned operation would be leaked. It was feared that Hezbollah might attempt to utilize them and launch a kidnap operation if it discovered that Israel knew about the tunnels.
Events
For the operation, the IDF deployed combat engineering units including the Yahalom special unit, bulldozers and other heavy equipment.
During the first day of the operation, on 4 December, the IDF said it had uncovered a tunnel near the Israeli town of Metula with an estimated length of that "extended more than " into Israel. The Washington Post reported that this tunnel was likely monitored for several years by Israel. While uncovering the first tunnel, the IDF placed a camera inside the tunnel and caught on video two suspected Hezbollah members inside, one of whom was identified by Israel as Dr. Imad "Azaladin" Fahs, who is reportedly known as a "commander for the Hezbollah observation unit on the border with Israel and a commander in the tunnel unit."
Hezbollah claimed that the man spotted in the tunnel is a drug smuggler, and is not among its ranks.
On 6 December 2018, UNIFIL confirmed the existence of the first cross-border tunnel. On the same day, the IDF said it discovered a second tunnel originating from the village of Ramyah near the border, and demanded that UNIFIL reach the tunnel from the Lebanese side and said that "whoever enters the underground perimeter endangers his life".
Also on that day, Israel demanded that Lebanon and UNIFIL destroy the tunnels, saying that it "holds the Lebanese government, the Lebanese Armed Forces and United Nations Interim Force in Lebanon responsible for all events transpiring in and emanating from Lebanon". UNIFIL said that it was "engaged with the parties to pursue urgent follow-up action". According to Al-Manar, the Lebanese Foreign Minister, Gebran Bassil instructed the Lebanese UN envoy to say that Israel is conducting "a diplomatic and political campaign against Lebanon in preparation for attacks against it." As of 8 December 2018, Lebanon has not responded publicly to the Israeli demand, with Lebanese sources telling Asharq Al-Awsat that "all concerned official parties were following up on the issue and they are exerting efforts to address it away from the media or political spotlight" and that Lebanon is working on a UN complaint asserting that Israel's "diplomatic and political campaign against Lebanon that are a precursor to waging attacks against it."
On 11 December 2018, the IDF said it located a third tunnel crossing into Israel. On the same day, UNIFIL confirmed the existence of the second cross-border tunnel.
On 16 December 2018, the IDF said it located a fourth tunnel crossing into Israel, and that as the tunnel had been rigged with explosives anyone entering it from the Lebanese side would be risking their life.
On 17 December 2018, IDF troops placed rolls of concertina wire on the Israeli side of the Blue Line. During placement of the wire, a non-violent confrontation took place between Israeli and Lebanese soldiers. Also on 17 December 2018, UNIFIL acknowledged the existence of four tunnels near the Israel–Lebanon border, and said "UNIFIL at this stage can confirm that two of the tunnels cross the Blue Line" in violations of United Nations Security Council Resolution 1701.
On 19 December 2018, in a special session of the United Nations Security Council, Israel urged the UNSC to condemn Hezbollah and designate it as a terrorist organization. Israel also accused Hezbollah of storing weapons in private homes. Jean-Pierre Lacroix, the UN peacekeeping chief, said UNFIL confirmed four tunnels including two that cross into Israel, a "serious violation" of the 2006 ceasefire resolution (1701). The Lebanese ambassador Amal Mudallali, said that Lebanon takes the matter seriously and remains committed to resolution 1701. However, Mudallali also accused Israel of repeated airspace violations by the Israeli Air Force. While several countries on the council joined Israel in condemning the tunnels, the council took no action at the end of a stormy session.
On 25 December, the IDF announced that it had found a fifth tunnel several days before, and that it had been neutralized with explosives.
On 13 January 2019, the IDF found a sixth tunnel, which it claimed was the largest and most sophisticated discovered. It had electrical lighting, a rail system for moving equipment, garbage disposal, and stairs. The IDF announced that this was the final tunnel, but that it was monitoring other areas along the border where Hezbollah was digging underground infrastructure that had yet to cross into Israel. With this discovery, the IDF announced the conclusion of Operation Northern Shield.
Lebanese view
According to an anonymous Lebanese security source speaking to the Lebanese newspaper Al Joumhouria, the tunnels were "old and deserted", and were exploited by Israel for political ends. Their source stated that Israel had announced the discovery of the tunnels long ago, but was only now using them for political gain.
Hassan Nasrallah, in response to the operation stated that he was surprised that it took so long for Israelis to find the tunnels, and that the operation was an "intelligence failure."
References
Conflicts in 2018
December 2018 events in Israel
Israel–Lebanon border
Iran–Israel proxy conflict
Hezbollah–Israel conflict
Military operations involving Israel
Tunnel warfare
Tunnels in Israel | Operation Northern Shield | [
"Engineering"
] | 1,471 | [
"Military engineering",
"Tunnel warfare"
] |
59,245,766 | https://en.wikipedia.org/wiki/Dispersal%20of%20invasive%20species%20by%20ballast%20water | The dispersal of invasive species by ballast water refers to the unintentional introduction of invasive species to new habitats via the ballast water carried by commercial shipping vessels. Ballast water spreads an estimated 7000 living species to new habitats across the globe. These species can affect the ecological balance of their new regions by outcompeting native species or otherwise impacting native ecosystems.
Ballast water
The purpose of ballast water is to provide transverse stability, improve propulsion and maneuverability, and to compensate for weight loss due to fuel and water consumption. Approximately 10 billion tons of ballast water is transported each year, accounting for 90% of our world trade. Typically, ballast water discharge contains a variety of biological materials including non-native, invasive, and exotic species that can cause extensive ecological and economic damage to aquatic ecosystems.
Throughout this process, large ships withdraw up to 20 million gallons of water at their specific loading ports. Including native species; both plant and animal, before disposing them at their next destination. However, when these invasive species are unloaded, specific conditions like temperature, salinity, lack of resources, and predator-to-prey competition affects how foreign species survive in non-native habitats. These factors cause stress within the ecosystems, throwing off ecological and environmental balance.
As new species are introduced to non-native ecosystems, interspecific competition often becomes more intense. If native species are out-competed by invasive species, it can affect the established predator-prey relationships within that region, possibly having disruptive effects on the wider food web.
Invasive species
Freshwater zebra mussel
Dreissena polymorpha, commonly known as the zebra mussel, live in freshwater and are native to southern lakes in Russia and Ukraine. The zebra mussel has become an invasive species that is frequently spread via ballast water. In North America, Great Britain, Ireland, Italy, Spain, and Sweden, the species has invaded native habitats. The mussels take oxygen and food from the water, limiting the resources available for native species and disrupting local ecosystems. Zebra mussels can have a significant impact on algae in the habitats they invade. Invasive zebra mussels, often in monotypic populations, have been shown to damage abiotic components found in invaded habitats such as boats, waterways, harbors, water treatment plants, and power plants.
Sea walnut
Mnemiopsis leidyi, commonly known as the sea walnut, is a ctenophore species native to the eastern coast of North and South America. Currently, Mnemiopsis leidyi has become invasive through the transfer of ballast water to the Black, Azov, Aegean and Marmara Seas, west coast of Sweden, and the Southern and Northern Baltic Sea. This carnivorous species feeds on zooplankton, crustaceans, fish eggs and larvae. Some individuals are known to consume individuals of their own species. Specifically, Mnemiopsis sp. has become an ecological problem for local fisheries because they have been linked to the diminishing zooplankton population.
Green crab
Carcinus maenas, commonly known as the green crab, is native to the Baltic Sea and the northeastern Atlantic Ocean. This species has become invasive to North America, South Africa, South America, Asia, and Australia. This widely spread invasive species is often distributed by ship ballast water. C. maenas is a voracious predator to many species such as worms, mollusks, oysters, and clams. The competitiveness and efficiency of this species out-competes native crabs and lobsters. Specifically, the green crab disrupts eelgrass beds, often home to diverse fish populations. For aquaculture and fishing industries, C. maenas poses a particular threat due to its appetite for valuable farmed mollusks.
See also
Ballast water discharge and the environment
Climate change and invasive species
References
Further reading
about the Great Lakes
about the Great Lakes
Invasive species
Environmental impact of shipping
Environmental conservation
Pest control | Dispersal of invasive species by ballast water | [
"Biology"
] | 797 | [
"Pest control",
"Pests (organism)",
"Invasive species"
] |
59,248,142 | https://en.wikipedia.org/wiki/SimThyr | SimThyr is a free continuous dynamic simulation program for the pituitary-thyroid feedback control system. The open-source program is based on a nonlinear model of thyroid homeostasis. In addition to simulations in the time domain the software supports various methods of sensitivity analysis. Its simulation engine is multi-threaded and supports multiple processor cores. SimThyr provides a GUI, which allows for visualising time series, modifying constant structure parameters of the feedback loop (e.g. for simulation of certain diseases), storing parameter sets as XML files (referred to as "scenarios" in the software) and exporting results of simulations in various formats that are suitable for statistical software. SimThyr is intended for both educational purposes and in-silico research.
Mathematical model
The underlying model of thyroid homeostasis is based on fundamental biochemical, physiological and pharmacological principles, e.g. Michaelis-Menten kinetics, non-competitive inhibition and empirically justified kinetic parameters. The model has been validated in healthy controls and in cohorts of patients with hypothyroidism and thyrotoxicosis.
Scientific uses
Multiple studies have employed SimThyr for in silico research on the control of thyroid function.
The original version was developed to check hypotheses about the generation of pulsatile TSH release. Later and expanded versions of the software were used to develop the hypothesis of the TSH-T3 shunt in the hypothalamus-pituitary-thyroid axis, to assess the validity of calculated parameters of thyroid homeostasis (including SPINA-GT and SPINA-GD) and to study allostatic mechanisms leading to non-thyroidal illness syndrome.
SimThyr was also used to show that the release rate of thyrotropin is controlled by multiple factors other than T4 and that the relation between free T4 and TSH may be different in euthyroidism, hypothyroidism and thyrotoxicosis.
Public perception, reception and discussion of the software
SimThyr is free and open-source software. This ensures the source code to be available, which facilitates scientific discussion and reviewing of the underlying model. Additionally, the fact that it is freely available may result in economical benefits.
The software provides an editor that enables users to modify most structure parameters of the information processing structure. This functionality fosters simulation of several functional diseases of the thyroid and the pituitary gland. Parameter sets may be stored as MIRIAM- and MIASE-compliant XML files.
On the other hand, the complexity of the user interface and the lack of the ability to model treatment effects have been criticized.
See also
Hypothalamic–pituitary–thyroid axis
Thyroid function tests
References
External links
of the SimThyr project
Curated information at Zenodo
Curated information at SciCrunch
Free science software
Free biosimulation software
Medical simulation
Free software programmed in Pascal
Scientific simulation software
Science software for macOS
Science software for Windows
Mathematical and theoretical biology
Computational biology
Cross-platform software
Biomedical cybernetics
Simulation software
Human homeostasis
Thyroid homeostasis | SimThyr | [
"Mathematics",
"Biology"
] | 640 | [
"Mathematical and theoretical biology",
"Human homeostasis",
"Applied mathematics",
"Computational biology",
"Homeostasis"
] |
59,248,409 | https://en.wikipedia.org/wiki/Palmitoleoylation | Palmitoleoylation is type of protein lipidation where the monounsaturated fatty acid palmitoleic acid is covalently attached to serine or threonine residues of proteins. Palmitoleoylation appears to play a significant role in trafficking and targeting and function of Wnt proteins.
O-Palmitoleoylation of Wnt proteins is catalysed by PORCN. The inverse reaction is done by NOTUM.
References
Post-translational modification | Palmitoleoylation | [
"Chemistry"
] | 102 | [
"Post-translational modification",
"Gene expression",
"Biochemical reactions"
] |
59,248,548 | https://en.wikipedia.org/wiki/Pump%E2%80%93probe%20microscopy | Pump–probe microscopy is a non-linear optical imaging modality used in femtochemistry to study chemical reactions. It generates high-contrast images from endogenous non-fluorescent targets. It has numerous applications, including materials science, medicine, and art restoration.
Advantages
The classic method of nonlinear absorption used by microscopists is conventional two-photon fluorescence, in which two photons from a single source interact to excite a photoelectron. The electron then emits a photon as it transitions back to its ground state. This microscopy method has been revolutionary in biological sciences because of its inherent three-dimensional optical sectioning capabilities.
Two-photon absorption is inherently a nonlinear process: fluorescent output intensity is proportional to the square of the excitation light intensity. This ensures that fluorescence is only generated within the focus of a laser beam, as the intensity outside of this plane is insufficient to excite a photoelectron.
However, this microscope modality is inherently limited by the number of biological molecules that can undergo both two-photon excitation and fluorescence.
Pump–probe microscopy circumvents this limitation by directly measuring excitation light. This expands the number of potential targets to any molecule capable of two-photon absorption, even if it does not fluoresce upon relaxation. The method modulates the amplitude of a pulsed laser beam, referred to as the pump, to bring the target molecule to an excited state. This will then affect the properties of a second coherent beam, referred to as the probe, based on the interaction of the two beams with the molecule. These properties are then measured by a detector to form an image.
Physics of pump–probe microscopy
Because pump–probe microscopy does not rely on fluorescent targets, the modality takes advantage of multiple different types of multiphoton absorption.
Two-photon absorption
Two-photon absorption (TPA) is a third-order process in which two photons are nearly simultaneously absorbed by the same molecule. If a second photon is absorbed by the same electron within the same quantum event, the electron enters an excited state.
This is the same phenomenon used in two-photon microscopy (TPM), but there are two key features that distinguish pump–probe microscopy from TPM. First, since the molecule is not necessarily fluorescent, a photodetector measures the probe intensity. Therefore, the signal decreases as two-photon absorption occurs, the reverse of TPM.
Second, pump–probe microscopy uses spectrally separated sources for each photon, whereas conventional TPM uses one source of a single wavelength. This is referred to as degenerate two-photon excitation.
Excited-state absorption
Excited-state absorption (ESA) occurs when the pump beam sends an electron into an excited state, then the probe beam sends the electron into a higher excited state. This differs from TPA primarily in the timescale over which it occurs. Since an electron can remain in an excited state for a period of nanoseconds, thus requiring longer pulse durations than TPA.
Stimulated emission
Pump–probe microscopy can also measure stimulated emission. In this case, the pump beam drives the electron to an excited state. Then the electron emits a photon when exposed to the probe beam. This interaction increases the probe signal at the detector site.
Ground-state depletion
Ground-state depletion occurs when the pump beam sends the electron into an excited state. However, unlike in ESA, the probe beam cannot send an electron into a secondary excited state. Instead, it sends remaining electrons from the ground state to the first excited state. However, since the pump beam has decreased the number of electrons in the ground state, fewer probe photons are absorbed, and the probe signal increases at the detector site.
Cross-phase modulation
Cross-phase modulation is caused by the Kerr effect, in which the refractive index of the specimen changes in the presence of a large electric field. In this case, the pump beam modulates the phase of the probe, which can then be measured through interferometric techniques. In certain cases, referred to as cross-phase modulation spectral shifting, this phase change induces a change to the pump spectrum that can be detected with a spectral filter.
Optical design
Excitation
Measuring nonlinear optical interactions requires a high level of instantaneous power and very precise timing. In order to achieve the high number of photons needed to generate these interactions while avoiding damage of delicate specimens, these microscopes require a modelocked laser. These lasers can achieve very high photon counts on the femtosecond timescale and maintain a low average power. Most systems use a Ti:Sapph gain medium due to the wide range of wavelengths that it can access.
Typically, the same source is used to generate the pump and the probe. An optical parametric oscillator (OPO) is used to convert the probe beam to the desired wavelength. The probe wavelength can be tuned over a large range for spectroscopic applications.
However, for certain types of two-photon interactions, it is possible to use separate pulsed sources. This is only possible with interactions such as excited-state absorption, in which the electrons remain in the excited state for several picoseconds. However, it is more common to use a single femtosecond source with two separate beam paths of different lengths to modulate timing between the pump and probe beams.
The pump beam amplitude is modulated using an acousto-optic or electro-optic modulator on the order of 107 Hz. The pump and probe beams are then recombined using a dichroic beamsplitter and scanned using galvanometric mirrors for point-by-point image generation before being focused onto the sample.
Detection
The signal generated by probe modulation is much smaller than the original pump beam, so the two are spectrally separated within the detection path using a dichroic mirror. The probe signal can be collected with many different types of photodetectors, typically a photodiode. Then, the modulated signal is amplified using a lock-in amplifier tuned to the pump modulation frequency.
Data analysis
Similar to hyperspectral data analysis, the pump–probe imaging data, known as a delay stack, has to be processed to obtain an image with molecular contrast of the underlying molecular species. Processing pump–probe data is challenging for several reasons – for example, the signals are bipolar (positive and negative), multi-exponential, and can be significantly altered by subtle changes in the chemical environment. The main methods for analysis of pump–probe data are multi-exponential fitting, principal component analysis, and phasor analysis.
Multi-exponential fitting
In multi-exponential fitting, the time-resolved curves are fitted with an exponential decay model to determine the decay constants. While this method is straightforward, it has low accuracy.
Principal component analysis
Principal component analysis (PCA) was one of the earliest methods used for pump–probe data analysis, as it is commonly used for hyperspectral data analysis. PCA decomposes the data into orthogonal components. In melanoma studies, the principal components have shown good agreement with the signals obtained from the different forms of melanin. An advantage of PCA is that noise can be reduced by keeping only the principal components that account for majority of the variance in the data. However, the principal components do not necessarily reflect actual properties of the underlying chemical species, which are typically non-orthogonal. Therefore, a limitation is that the number of unique chemical species cannot be inferred using PCA.
Phasor analysis
Phasor analysis is commonly used for fluorescence-lifetime imaging microscopy (FLIM) data analysis and has been adapted for pump–probe imaging data analysis. Signals are decomposed into their real and imaginary parts of the Fourier transform at a given frequency. By plotting the real and imaginary parts against one another, the distribution of different chromophores with distinct lifetimes can be mapped. In melanoma studies, this approach has again shown to be able to distinguish between the different forms of melanin. One of the main advantages of phasor analysis is that it provides an intuitive qualitative, graphical view of the content It has also been combined with PCA for quantitative analysis.
Applications
The development of high-speed and high-sensitivity pump–probe imaging techniques has enabled applications in several fields, such as materials science, biology, and art.
Materials science
Pump–probe imaging is ideal for the study and characterization of nanomaterials, such as graphene, nanocubes, nanowires, and a variety of semiconductors, due to their large susceptibilities but weak fluorescence. In particular, single-walled carbon nanotubes have been extensively studied and imaged with submicrometer resolution, providing details about carrier dynamics, photophysical, and photochemical properties.
Biology
The first application of the pump–probe technique in biology was in vitro imaging of stimulated emission of a dye-labelled cell. Pump–probe imaging is now widely used for melanin imaging to differentiate between the two main forms of melanin eumelanin (brown/black) and pheomelanin (red/yellow). In melanoma, eumelanin is substantially increased. Therefore, imaging the distribution of eumelanin and pheomelanin can help to distinguish benign lesions and melanoma with high sensitivity
Art
Artwork consists of many pigments with a wide range of spectral absorption properties, which determine their color. Due to the broad spectral features of these pigments, the identification of a specific pigment in a mixture is difficult. Pump–probe imaging can provide accurate, high-resolution, molecular information and distinguish between pigments that may even have the same visual color.
References
Physical chemistry | Pump–probe microscopy | [
"Physics",
"Chemistry"
] | 2,004 | [
"Physical chemistry",
"Applied and interdisciplinary physics",
"nan"
] |
59,249,253 | https://en.wikipedia.org/wiki/Paul%20H.%20Silverman | Paul Hyman Silverman (October 8, 1924 – July 15, 2004) was an American medical researcher in the fields of immunology, epidemiology, and parasitology. He was recognized for his research on stem cells and on the human genome.
Early life and education
Silverman was born on October 8, 1924, in Minneapolis, Minnesota. Growing up, he became fascinated with reading, and he won a local prize for his reading comprehension ability. He attended the University of Minnesota as a pre-medical student while also working three part-time jobs. He went on to serve in a MASH in the United States Army during World War II. He received a bachelor's degree from Roosevelt University. In 1951, Silverman received his M.S. from Northwestern University, after which he moved to Israel with his family. In Israel, he began research on malaria, which he continued to study for many years thereafter. In 1953, he and his family moved again, this time to England. There, he began studying at the Liverpool School of Tropical Medicine, from which he received his Ph.D. in parasitology and epidemiology in 1955.
Academic career
Silverman returned to the United States when he was 39 years old. He then accepted a position at the University of Illinois at Urbana–Champaign before moving to the University of New Mexico in 1972. At the University of New Mexico, he and his team developed a killed malaria vaccine based on Jonas Salk's polio vaccine. He became Vice President for Research and Graduate Studies at the University of New Mexico in 1975, and joined the State University of New York as their Provost for Research and Graduate Studies in 1978. In 1980, he became president of the University of Maine, a position he held until 1984. At the University of Maine, he was credited with expanding the scope of research activities. In 1984, he returned to research as a senior scientist at the Lawrence Berkeley National Laboratory. He also served at the University of California, Berkeley as Associate Laboratory Director for Life Sciences and Director of the Donner Lab. In 1987, he helped organize a partnership between the University of California, Berkeley and Lawrence Livermore National Laboratory to establish the first research center dedicated to the study of the human genome. He then worked at Beckman Instruments for several years before being appointed Associate Chancellor for Health Sciences at the University of California, Irvine in 1994, a position he held until his retirement in 1996. Also in 1994, he was elected to the World Academy of Art and Science. In the fall of 2003, he gave the commencement speech to the class of Roosevelt University, from which he received an honorary doctorate of human letters.
Research and views
Silverman was a member of the Human Genome Project's advisory committee. After its results showed that humans had about 30,000 genes, he noted that this suggested that genes were much less important causes of human diseases than previously thought. In an article published in The Scientist shortly before his death, he urged his fellow researchers to abandon genetic determinism, asking, "With only 30,000 genes, what is it that makes humans human?"
Personal life
Silverman met his wife, Nancy Josephs, while he was serving in the Army during World War II. The two married on May 20, 1945, and their son, Daniel, was born in 1950; they also had a daughter, Claire. Paul Silverman died on July 16, 2004, of complications resulting from a bone marrow transplant he had received to treat his myelofibrosis.
References
1924 births
2004 deaths
American medical researchers
American geneticists
20th-century American biologists
Human Genome Project scientists
Scientists from Minneapolis
United States Army personnel of World War II
Roosevelt University alumni
Northwestern University alumni
Alumni of the Liverpool School of Tropical Medicine
University of Illinois Urbana-Champaign faculty
University of New Mexico faculty
State University of New York faculty
Presidents of the University of Maine
Lawrence Berkeley National Laboratory people
University of California, Berkeley faculty
University of California, Irvine faculty
American parasitologists
Human geneticists | Paul H. Silverman | [
"Engineering"
] | 812 | [
"Human Genome Project scientists"
] |
59,254,904 | https://en.wikipedia.org/wiki/G.%20Peter%20Lepage | G. Peter Lepage (born 13 April 1952) is a Canadian American theoretical physicist and an academic administrator. He was the Harold Tanner Dean of the College of Arts and Sciences at Cornell University from 2003 to 2013.
Early life and education
Gerard Peter Lepage was born in Canada in 1952. Lepage studied at McGill University and graduated with a bachelor's degree in honours physics in 1972 and the University of Cambridge with a master's degree (M.A.St - Part III of the Mathematical Tripos) in 1973. In 1978, he received his PhD in theoretical physics from Stanford University.
Academic career
Lepage was a research associate at the Stanford Linear Accelerator Center in 1978. He was a postdoctoral research associate at the Laboratory of Nuclear Studies, Cornell University from 1978 to 1980. In 1980, he joined the physics faculty at Cornell University where he became a professor. He received academic tenure in 1984 after only four years on the university faculty. From 1999 to 2003, he was the chair of Cornell's physics department. He was appointed the Harold Tanner Dean of the College of Arts and Sciences, serving from 2003 to 2013.
He is a Fellow of the American Academy of Arts and Sciences and a Fellow of the American Physical Society. He was previously an Alfred P. Sloan Fellow (1983–85; 1990) and John Simon Guggenheim Fellow (1996–97) Since 2012 he has been a member of the National Science Board.
G. Peter Lepage has been a visiting scholar at a number of institutions: the Institute for Advanced Study, Princeton; Department of Applied Mathematics and Theoretical Physics, Cambridge; the University of California Institute of Theoretical Physics, Santa Barbara, the Fermi National Accelerator Center near Chicago, and the Institute for Nuclear Theory, Seattle.
He was on the editorial board of Physical Review D and Physical Review Letters and received the Outstanding Referee Award from the APS in 2009. He has served on the scientific program committees for the Stanford Linear Accelerator Center, the DOE-NSF National Computational Infrastructure for Lattice Gauge Theory, the NSF's Institute for Nuclear Theory in Seattle, the International Particle Data Group, and the NSF's Institute for Theoretical Physics in Santa Barbara.
He was the co-chair of the working group for the President Obama’s Council of Advisors on Science and Technology (PCAST) on STEM teaching at colleges and universities, which in 2012 produced the acclaimed report, “Engage to Excel: Producing One Million Additional College Graduates with Degrees in Science, Technology, Engineering, and Mathematics.” He has served on the technical advisory committee for the Association of American Universities’ Undergraduate STEM Education Initiative, and is vice chair of the National Science Board’s Committee on Education and Human Resources.
He is also involved in innovations in pedagogy, especially physics education at all levels. He spearheads the Active Learning Initiative (ALI) in Cornell's college of arts and sciences, a five-year pilot project, funded by 1987 alumni, Alex and Laura Hanson, used to enhance strategies for interactive classroom learning using emerging technologies.
Research
In the late 1970s and early 1980s, he was known for his research with Stanley Brodsky on quantum chromodynamics (QCD) and perturbation theory of scattering processes, His research focus examines high precision calculations, adapted to renormalization techniques and effective field theory. This method is then applied to the fields of QCD in atomic physics, computational quantum field theory, condensed matter physics, nuclear physics (little body problem), systems of heavy quarks and exclusive scattering processes with high momentum transfer.
His research also covers high-performance computing (HPC) or large scale numerical simulations of non-perturbative lattice QCD, leading in part to a range of calculations at different observation sizes – quarks, gluons and hadron masses, coupling constants and mixing angles in the Standard Model, magnetic moment of muons and allowed to determine the QCD contributions for precision testing of the Standard Model (distinguishable from possible contributions of new physics beyond the standard model). These particles describe the inner structure of protons, neutrons and other sub-nuclear particles. His research resulted in the VEGAS algorithm for adaptive method for reducing error in Monte Carlo simulations in interaction physics by using a known or approximate probability distribution function.
In 2016, Lepage received the J. J. Sakurai Prize from the American Physical Society for “innovative applications of quantum field theory in elementary particle physics, in particular for the justification of the theory of exclusive processes, the development of nonrelativistic effective field theories and the determination of parameters of the standard model with lattice theories.”
He has authored more than 250 scientific publications. In 2002, together with fellow academics, Carolyn (Biddy) Martin and Mohsen Mostafavi, he co-edited a book on the future and relevance of the humanities, “Do the Humanities Have to Be Useful?”
Personal life
G. Peter Lepage is married to Deborah O'Connor and they have three sons: Michael, Daniel and Matthew. O'Connor studied pharmacology at Stanford, worked in biochemistry at Cornell and served on the Ithaca City School District Board of Education.
References
1952 births
Living people
20th-century American physicists
Alumni of the University of Cambridge
American academic administrators
Canadian particle physicists
20th-century Canadian physicists
21st-century Canadian physicists
Cornell University faculty
Fellows of the American Academy of Arts and Sciences
Fellows of the American Physical Society
McGill University Faculty of Science alumni
Particle physicists
Quantum computing
Quantum physicists
Sloan Research Fellows
Stanford University alumni
Theoretical physicists
J. J. Sakurai Prize for Theoretical Particle Physics recipients | G. Peter Lepage | [
"Physics"
] | 1,134 | [
"Theoretical physicists",
"Theoretical physics",
"Quantum physicists",
"Quantum mechanics",
"Particle physics",
"Particle physicists"
] |
59,255,648 | https://en.wikipedia.org/wiki/Our%20Heavenly%20Bodies | Our Heavenly Bodies (, literally: Wonder of the Creation) is a 1925 German educational film written by Hanns Walter Kornblum and Ernst Krieger which attempts to represent everything known about the cosmos at the time. It covers the origin and mechanics of the Solar System, gravitation, the stars, and the nature of galaxies.
The film is a prime example of the early German "Kulturfilm", which are regarded as predecessors of the modern film documentary.
It features a large variety of special effects and animations, as well as fantastical depictions of travel around the Solar System and to the stars. Prints were color-tinted and color-toned for effect.
The film has been reconstructed in 2008 by Munich Film Archive using material from the National Audiovisual Institute (Finland) in Helsinki and the Deutsche Kinemathek in Berlin. The current rights holder is the Friedrich-Wilhelm-Murnau Foundation.
Acts
1) On the Road to Truth ()
A history of cosmology.
2) The Night Sky ()
The Moon: its motion and faces, its tides, lunar eclipses; the fixed stars, Berlin-Babelsberg Observatory, constellations, the North Star, comets, meteors and falling stars.
3) The Star of Day ()
Sunspots, auroras, solar eclipse, solar prominences, night, day and meridians, heating of the equator vs. poles, earthly seasons.
4) A Flight to the Moon ()
Introduces a "fantasty ship" pulled by "huge electrical energies", calls it a "space ship". Depicts its launch, discusses the nature of the vacuum of space, the idea of a Moon-day, the Earth as seen from the Moon.
5) The Sun's Children ()
Continues the imaginary journey to Mercury (mentions that it's thought that Mercury always presents the same face to the Sun), Venus, Mars, its seasons and polar caps, the observed canals. Depicts an imaginary landing, and people bouncing around in reduced gravity. Asteroids.
A depiction of Gulliver's Travels in Lilliput illustrates Jupiter's size.
The moons of Jupiter. Depicts a person labouring to crawl on the surface of Jupiter, and giants residing on Jupiter.
Saturn's rings as "numberless small bodies", depicts the rings as seen from Saturn, and Saturn's moons;
Uranus; Neptune, its discovery, and its one big moon.
6) At the Gates of Infinity ()
Explains that there is no up or down in space, and attempts to show people in zero gravity;
discusses nebulas.
The travellers use a flat view screen to look back on Earth, where they witness historical events.
As the ship proceeds to travel faster than light, the travellers view the same historical events in reverse.
The ship then proceeds much faster than light to visit binary stars — Algol, globular cluster. The fantasy comes to an end as they leave the last star of the Milky Way. (In 1924 it was controversial whether the Milky Way comprised the universe or not.)
7) Becoming and Waning in Outer Space ()
Discusses the relative movements of stars; that the shape of constellations is a matter of perspective;
a mass of gas taking a spiral disk shape, wherein knots form to become planets — in their youth as gas, forming a solid kernel — formation of (terrestrial) planets;
erosion of surface of Earth, prehistoric creatures.
Speculates on the future of the Earth — shows people freezing, then a very extended depiction of the world burning up upon being hit by another heavenly body.
Further Credits
Scientific review:
Professor Dr. Guthnick
Professor Dr. Kopff
Professor Dr. Ludendorff
Professor Dr. Solger
Constructions:
Gustav Hennig
Hans Minzloff
Walter Reimann
Karl Stahl-Urach
Film Reconstruction
Stefan Drössler
Christian Ketels
Gerhard Ullmann
"Thanks to"
Antti Alanen
Annette Groschke
Juha Kindberg
Konrad und Wolfgang Kornblum
Eva Orbanz
Jon Wengström
Reception and legacy
The film is described as being "overwhelming", a "wild success" at the time, in contrast with the Ufa's later, better known production Metropolis.
Scenes of the film are often described as forerunners of space science-fiction films,
especially Stanley Kubrick's 2001: A Space Odyssey.
The spirit and content of the film more closely parallels that of Carl Sagan's TV series Cosmos: A Personal Voyage.
References
External links
1925 films
German documentary films
Documentary films about outer space
Astronomy education works
Films about the Solar System
Earth in film
Moon in film
Venus in film
Mars in film
Jupiter in film
Saturn in film
Neptune in film
Space adventure films
Fiction about interstellar travel
German silent feature films
1925 documentary films
German black-and-white films
Silent adventure films
1920s German films | Our Heavenly Bodies | [
"Astronomy"
] | 989 | [
"Astronomy education",
"Space art",
"Documentary films about outer space",
"Works about astronomy",
"Astronomy education works"
] |
59,257,416 | https://en.wikipedia.org/wiki/Heterometallic%20copper-aluminum%20superatom | The heterometallic copper-aluminum superatom is a Mackay‐type icosahedral cluster compound with formula [Cu43Al12](Cp*)12. It is an open‐shell 67‐electron superatom. It is notable for its large electron count compared to other heterometallic superatoms and its unprecedented electron structure of an open-shell configuration. it was the largest heterometallic superatom to be created using wet chemical synthesis.
Synthesis
Combining (pentamethylcyclopentadienyl)aluminium(I) with in benzene at 78 °C under an inert atmosphere for 48 hours, followed by slow cooling, forms black cocrystals of the compound with benzene:
The material is created from single-atom sources of copper and aluminium, which spontaneously separate from the organic compounds to form the superatom cluster. The exergonic nature of the reaction demonstrates that this specific arrangement of copper and aluminum atoms is stable.
Structure
According to crystallographic and computational analysis, the complex contains a central copper atom surrounded by a first icosahedral shell containing twelve copper atoms, followed by a second icosahedral shell containing twelve aluminium atoms (located at the vertices of the icosahedron) and thirty copper atoms (located at the midpoints of the edges). This central group of metal atoms (of radius 5.137 Å) is surrounded by twelve pentamethylcyclopentadienyl ligands (one attached to each aluminium atom) that assist in protecting it against further reaction. It was the first ligated heterometallic Mackay-type cluster to be discovered.
References
External links
https://iscr.univ-rennes1.fr/umr/news/article/open-shell-67-electron-superatom?lang=en
Cluster chemistry
Copper compounds
Aluminium compounds
Cyclopentadienyl complexes | Heterometallic copper-aluminum superatom | [
"Chemistry"
] | 393 | [
"Cluster chemistry",
"Organometallic chemistry",
"Cyclopentadienyl complexes"
] |
59,263,270 | https://en.wikipedia.org/wiki/Extrinsic%20mortality | Extrinsic mortality is the sum of the effects of external factors, such as predation, starvation and other environmental factors not under control of the individual that cause death. This is opposed to intrinsic mortality, which is the sum of the effects of internal factors contributing to normal, chronologic aging, such as, for example, mutations due to DNA replication errors, and which determined species maximum lifespan. Extrinsic mortality plays a significant role in evolutionary theories of aging, as well as the discussion of health barriers across socioeconomic borders.
Evolutionary theories of aging
Extrinsic mortality is implicit in both classical theories of aging and non-classical studies of aging. In both cases, its existence causes a selective pressure for either longer lifespans and later reproductive periods or shorter lifespans and earlier reproductive periods.
Classical theories of aging include:
Mutation Accumulation Theory of Aging - Because extrinsic mortality is so high in the natural world, few animals survive to old age. As a result, random harmful germ line mutations accumulate with little to no selective disadvantage.
Antagonistic Pleiotropy Hypothesis - Because pleiotropic genes that express phenotypes that increase fitness in early life and other phenotypes that decrease fitness in later life are generally selected for, harmful phenotypes contribute to senescence and an evolutionary tradeoff between lifespan and reproduction develops.
Disposable Soma Theory of Aging - Because resources are often limited and the influence of natural selection declines with age for similar reasons as the Mutation Accumulation theory of aging, organisms that invest greater amounts of energy into earlier reproduction rather than long term body maintenance are more successful. The lack of somatic maintenance and anti-aging mechanisms leads to senescence.
These classical evolutionary theories of aging postulate that quantities of extrinsic mortality factors should inversely correlate with lifespan. In the Mutation Accumulation Theory of Aging, increased quantities of extrinsic mortality factors prevent selection against the development of random germ line mutations. In the Antagonistic Pleiotropy Hypothesis, extrinsic mortality factors prevent selection against pleiotropic genes expressing harmful phenotypes later in life. In the Disposable Soma Theory of Aging, extrinsic mortality factors prevent organisms from selecting mechanisms that encourage long term maintenance. However, some non-classical evolutionary theories of aging challenge this notion and there are examples of the opposite, i.e. quantities of extrinsic mortality factors correlate with lifespan.
Non-classical studies of aging tend to use models, whether they be biological or computational, to demonstrate aging mechanisms and trends across organisms. In a study conducted on guppies, it was found that fish at higher risk of predation, an extrinsic mortality factor, do not demonstrate an earlier onset of senescence than fish at a lower risk of predation. In addition, a study conducted on the nematode Caenorhabditis remanei revealed that nonrandom extrinsic mortality factors that are more representative of those faced by nematodes in nature lead to an increased lifespan and decreased senescence. Finally, a computational model using mammalian life tables revealed that extrinsic mortality factors had the ability to increase, decrease or have no effect on senescence across species. These studies contrast the theorized correlation between extrinsic mortality factors and decreased lifespan and reproductive age.
The divergence between classical theories of aging and non-classical studies of aging may be due to the influence of density dependence as an additional factor that interacts with extrinsic mortality to produce varying effects on reproduction and senescence. Through the use of theoretical models, the interaction between extrinsic mortality and density dependence has been shown to be a compensation mechanism, where the higher the strength of extrinsic mortality factors, the lower the influence of density dependence. This compensates the influence of both factors on senescence only if density dependence acts on survival independently of age.
In modern human populations
Minimization in developed countries
In modern human populations, life expectancy has increased greatly due to advances in medicine lowering death in childbirth and preventing fatal childhood infections. This has led to a shift in the distribution of death from younger to older people, and was accompanied by a transition from extrinsic factors in death to a mixture of both intrinsic and extrinsic factors. Because extrinsic mortality factors have become relatively unimportant in the cause of death in most developed countries, an increasing proportion of the population of these countries is composed of older people beyond the period of reproduction and grand-parenting. Therefore, the reduction of extrinsic mortality factors in developed human populations has contributed to the ability of people to live longer than they can reproduce. However, it is important to note that the ability of people to live longer than they can reproduce is potentially attributed to the grandmother hypothesis, which states that menopause allows older women to provide alloparental care for grandchildren in order to increase their fitness.
Risk in developed countries
While extrinsic mortality is reduced both within developed countries and beyond, extrinsic risk is not perceived to be applied equally. A study conducted in North America demonstrates that in areas of lower socioeconomic status, people perceive themselves to be more susceptible to extrinsic mortality factors rather than intrinsic mortality factors. In addition, increased perceived extrinsic mortality risk is associated with a smaller investment in preventative health measures. In order to increase public health efficacy, the study states that reconstructing how extrinsic mortality risk is perceived in populations of lower socioeconomic status could limit psychological mechanisms that lead to the perceived fatalism of extrinsic risks.
On reproductive strategies in undeveloped countries
A study conducted on women living in rural Dominica demonstrates reproductive strategies that correspond with changing levels of extrinsic mortality factors, measured by infant mortality rates. The study demonstrates that in times of historically low infant mortality rates, women reproduced later in life. In times of high infant mortality rates, women reproduced earlier in life. In times of extremely high infant mortality rates, women tended to reproduce later in life, though the study hypothesizes that this may not be due to infant mortality specifically, rather the factors contributing to infant mortality leading to energetic stress, which prevented earlier pregnancy.
The correlation between this pattern and the pattern of reproduction predicted by the Disposable Soma Theory of Aging is evident in that both the theory and the pattern of reproduction of Dominican women predict earlier reproduction in times of extrinsic stress.
References
Ageing
Ailments of unknown cause
Old age
Senescence
Causes of death | Extrinsic mortality | [
"Chemistry",
"Biology"
] | 1,351 | [
"Senescence",
"Metabolism",
"Cellular processes"
] |
59,263,559 | https://en.wikipedia.org/wiki/Ilse%20Fischer | Ilse Fischer (born 29 June 1975) is an Austrian mathematician whose research concerns enumerative combinatorics and algebraic combinatorics, connecting these topics to representation theory and statistical mechanics. She is a professor of mathematics at the University of Vienna.
Education and career
Fischer was born in Klagenfurt. She studied at the University of Vienna beginning in 1993, earning a master's degree (mag. rer. nat.), doctorate (dr. rer. nat.), and habilitation there respectively in 1998, 2000, and 2006. Her doctoral dissertation, Enumeration of perfect matchings: Rhombus tilings and Pfaffian graphs, was jointly supervised by Christian Krattenthaler and Franz Rendl, and her habilitation thesis was A polynomial method for the enumeration of plane partitions and alternating sign matrices.
She worked as an assistant at Alpen-Adria-Universität Klagenfurt from 1999 to 2004, with a year of postdoctoral research at the Massachusetts Institute of Technology in 2001. She moved to the University of Vienna in 2004, and at Vienna she was promoted to associate professor in 2011 and to full professor in 2017.
Recognition
Fischer won the 2006 Dr. Maria Schaumayer Prize,
and the 2009 Start-Preis of the Austrian Science Fund.
With Roger Behrend and Matjaž Konvalinka, Fischer is a winner of the 2019 David P. Robbins Prize of the American Mathematical Society and Mathematical Association of America, for their joint research on alternating sign matrices.
References
External links
1975 births
Living people
Scientists from Klagenfurt
Austrian mathematicians
Austrian women mathematicians
Combinatorialists
University of Vienna alumni
Academic staff of the University of Vienna | Ilse Fischer | [
"Mathematics"
] | 354 | [
"Combinatorialists",
"Combinatorics"
] |
59,263,807 | https://en.wikipedia.org/wiki/NGC%205395 | NGC 5395 is an interacting spiral galaxy located at a distance of 160 million light years, but receding away from the Earth at 3511 kilometers (2181.6 miles) per second, in the constellation Canes Venatici. It was discovered by William Herschel on May 16, 1787. NGC 5395 and NGC 5394 are included in the Atlas of Peculiar Galaxies as Arp 84 in the category "Spiral galaxies with large high surface brightness companions".
NGC 5395 is the larger spiral galaxy interacting with smaller barred spiral galaxy, NGC 5394. NGC 5395 is nearly face-on, with a diameter of around 140,000 light-years across. NGC 5395 has a bright central region and is distorted due to the interaction with NGC 5394. The larger of the two rings around the galaxy forms a ring off the center of the galaxy. Dust lanes can be seen throughout the galaxy.
NGC 5394 is the smaller barred spiral galaxy interacting with larger spiral galaxy, NGC 5395. NGC 5394 has an oval disk, with a diameter of around 90 thousand light years across. It is also located at a distance of 160 million light-years across but receding away from the Earth at a distance of 3448 kilometers (2142.4 miles) per second. Most of the gas is concentrated at the center of the galaxy, however, two out of the three spiral arms show no sign of ongoing star formation.
NGC 5395 is a Seyfert 2 galaxy.
Supernova
One supernova has been detected in NGC 5395, Type Ic supernova SN 2000cr. It was discovered on June 25.90 and 25.94 (UTC) at magnitude 17.0 lying northeast of the nucleus.
See also
List of NGC objects (5001–6000)
References
External links
5395
Canes Venatici
Unbarred spiral galaxies
Interacting galaxies
Seyfert galaxies | NGC 5395 | [
"Astronomy"
] | 399 | [
"Canes Venatici",
"Constellations"
] |
59,263,836 | https://en.wikipedia.org/wiki/Three-photon%20microscopy | Three-photon microscopy (3PEF) is a high-resolution fluorescence microscopy based on nonlinear excitation effect. Different from two-photon excitation microscopy, it uses three exciting photons. It typically uses 1300 nm or longer wavelength lasers to excite the fluorescent dyes with three simultaneously absorbed photons. The fluorescent dyes then emit one photon whose energy is (slightly smaller than) three times the energy of each incident photon. Compared to two-photon microscopy, three-photon microscopy reduces the fluorescence away from the focal plane by , which is much faster than that of two-photon microscopy by . In addition, three-photon microscopy employs near-infrared light with less tissue scattering effect. This causes three-photon microscopy to have higher resolution than conventional microscopy.
Concept
Three-photon excited fluorescence was first observed by Singh and Bradley in 1964 when they estimated the three-photon absorption cross section of naphthalene crystals. In 1996, Stefan W. Hell designed experiments to validate the feasibility of applying three-photon excitation to scanning fluorescence microscopy, which further proved the concept of three-photon excited fluorescence.
Three-photon microscopy shares a few similarities with Two-photon excitation microscopy. Both of them employ the point scanning method. Both are able to image 3D samples by adjusting the position of the focus lens along the axial and lateral directions. The structures of both systems do not require a pinhole to block out-focus light. However, three-photon microscopy differs from Two-photon excitation microscopy in their Point spread function, resolution, penetration depth, resistance to out-of-focus light and strength of photobleaching.
In three-photon excitation, the fluorophore absorbs three photons almost simultaneously. The wavelength of the excitation laser is about 1200 nm or more in three photon microscopy with the emission wavelength slightly longer than one-third of the excitation wavelength. Three photon microscopy has deeper tissue penetration because of the longer excitation wavelengths and the higher order nonlinear excitation. However, a three-photon microscope needs a laser with higher power due to relatively smaller cross-section of the dyes for three-photon excitation, which is on the order of . This is much smaller than the typical two-photon excitation cross-sections of . The Ultrashort pulses are usually around 100 fs.
Resolution
For three photon fluorescence scanning microscopy, the three dimensional intensity point-spread function (IPSF) can be denoted as,
,
where denotes the 3-D convolution operation, denotes the intensity sensitivity of an incoherent detector, and , denotes the 3-D IPSF for the objective lens and collector lens in single-photon fluorescence, respectively. The 3-D IPSF can be expressed in
,
where is a Bessel function of the first kind of order zero. The axial and radial coordinates and are defined by
and
,
where is the numerical aperture of the objective lens, is the real defocus, and is the radial coordinates.
Coupling with other multiphoton techniques
Correlative images can be obtained using different multiphoton schemes such as 2PEF, 3PEF, and third-harmonic generation (THG), in parallel (since the corresponding wavelengths are different, they can be easily separated onto different detectors). A multichannel image is then constructed.
3PEF is also compared to 2PEF: it generally gives a smaller degradation of the signal-to-background ratio (SBR) with depth, even if the emitted signal is smaller than with 2PEF.
Development
After three-photon excited fluorescence was observed by Singh and Bradley and further validated by Hell, Chris Xu and Watt W. Webb reported measurement of excitation cross sections of several native chromophores and biological indicators, and implemented three-photon excited fluorescence in Laser Scanning Microscopy of living cells. In November 1996, David Wokosin applied three photon excitation fluorescence for fixed in vivo biological specimen imaging.
In 2010s, three photon microscopy was applied for deep tissue imaging using excitation wavelengths beyond 1060 nm. In January 2013, Horton, Wang, Kobat and Xu invented in vivo deep imaging of an intact mouse brain by employing point scanning method to three photon microscope at the long wavelength window of 1700 nm. In February 2017, Dimitre Ouzounov, Tainyu Wang, and Chris Xu demonstrated deep activity imaging of GCaMP6-labeled neurons in the hippocampus of an intact, adult mouse brain using three-photon microscopy at the 1300 nm wavelength window. In May 2017, Rowlands applied wide-field three-photon excitation to three photon microscope for larger penetration depth. In Oct 2018, T Wang, D Ouzounov, and C Xu were able to image vasculature and GCaMP6 calcium activity using three photon microscope through the intact mouse skull.
Applications
Three-photon microscopy has similar application fields with two-photon excitation microscopy including neuroscience, and oncology. However, compared to standard single-photon or two-photon excitation, three-photon excitation has several benefits such as the use of longer wavelengths reduces the effects of light scattering and increasing the penetration depth of the illumination beam into the sample. The nonlinear nature of three photon microscopy confines the excitation target to a smaller volume, reducing out-of-focus light as well as minimizing photobleaching on the biological sample. These advantages of three-photon microscopy gives it an edge in visualize in vivo and ex vivo tissue morphology and physiology at a cellular level deep within scattering tissue and Rapid volumetric imaging. In the recent study, Xu has demonstrated the potential of three-photon imaging for noninvasive studies of live biological systems. The paper used three-photon fluorescence microscopy at a spectral excitation window of 1,320 nm to imaging the mouse brain structure and function through the intact skull with high spatial and temporal resolution(The lateral and axial FWHM was 0.96μm and 4.6μm) and large FOVs (hundreds of micrometers), and at substantial depth(>500 μm). This work demonstrates the advantage of higher-order nonlinear excitation for imaging through a highly scattering layer, in addition to the previously reported advantage of 3PM for deep imaging of densely labeled samples. Localized isomerization of photoswitchable drugs in vivo using three-photon excitation at 1560 nm has also been reported and used to control neuronal activity in a pharmacologically specific way.
See also
Laser scanning
Nonlinear optics
Two-photon excitation microscopy
References
Fluorescence techniques
Cell imaging
Laboratory equipment
Microscopy
Optical microscopy | Three-photon microscopy | [
"Chemistry",
"Biology"
] | 1,379 | [
"Optical microscopy",
"Cell imaging",
"Fluorescence techniques",
"Microscopy"
] |
59,264,881 | https://en.wikipedia.org/wiki/Al%20Hefaiyah%20Conservation%20Centre | Al Hefaiyah Mountain Conservation Centre () is a wildlife reserve and visitor centre located west of the coastal town of Kalba in the Emirate of Sharjah, the U.A.E.
Facilities
Opened in 2016, the Conservation Centre is a wildlife sanctuary and visitor centre, with some 30 animals preserved at the centre, including Arabian leopards, which are thought to now be extinct in the wild in the United Arab Emirates. It has been hailed as a major step forward in the conservation of endangered mountain species in the UAE, and in 2016, it won the Middle East Architect educational project of the year award. In March 2024, Sheikh Dr. Sultan bin Muhammad Al Qasimi, the Ruler of Sharjah, unveiled the Al Hefaiyah Lake project.
Fauna
Developed by the Sharjah Investment and Development Authority (Shurooq), the Centre is operated by the Sharjah Environment and Protected Areas Authority. The centre comprises a number of landscape enclosures in which mountain fauna are housed in their natural environment. Many of the species housed at the centre were previously at Sharjah's Breeding Centre for Endangered Arabian Wildlife (BCEAW) and are indigenous to the regions of Wadi Al Helo, Khor Fakkan, and Kalba in Al-Hajar Mountains.
Outdoor animals include Arabian leopard, rock hyrax, Arabian and goitered gazelles, caracal, Arabian oryx, tahr, Arabian wolf, and striped hyena. In addition to the critically endangered leopard, the Arabian wolf (Canis lupus arabs) and Arabian tahr (Arabitragus jayakari) are designated threatened species by the International Union for Conservation of Nature (IUCN).
Smaller species are housed indoors at the centre, and include snakes, lizards (such as uromastyx) and nocturnal hedgehogs.
Visitors to the centre travel around the outdoor areas in golf buggies, with guides, and observe a number of animals in their natural habitat. The centre also plays host to art exhibitions, education programs, fundraisers and other events.
Artworks
The centre houses several permanent artworks commissioned by the EPPA (Environment and Protected Areas Authority), including six sound installations by Bradley-Weaver, local designer Khalid Mezaina and artist Joris De Raedt.
See also
Al Ain Zoo
Emirates Park Zoo
Dubai Dolphinarium
Dubai Safari Park
Dubai Zoo
Gulf of Oman
References
External links
مركز الحفية لصون البيئة الجبلية (In Arabic)
مركز الحفية لصون البيئة الجبلية .. مشروع مزج التثقيف بالمعرفة (YouTube)
مركز الحفية لصون البيئة الجبلية ومركز كلباء للطيور الجارحة في الشارقة
Al Hefaiyah Mountain Conservation Centre | Kalba | Location
Visiting Al Hefaiyah Mountain Conservation Centre in Kalba Sharjah 27.09.2018
Arabian Tahr (Arabitragus jayakari) at Al Hefaiyah Mountain Conservation Centre in Kalba Sharjah
Wildlife sanctuaries of the United Arab Emirates
Wildlife conservation
Zoos in the United Arab Emirates | Al Hefaiyah Conservation Centre | [
"Biology"
] | 717 | [
"Wildlife conservation",
"Biodiversity"
] |
55,884,502 | https://en.wikipedia.org/wiki/Levington%20Research%20Station | The Levington Research Station is a fertiliser research institute in Suffolk.
History
Fisons
It was opened by Fisons in 1957. It received a Civic Trust Award in 1959. Fisons sold the property in 1981.
Around three hundred people worked at the site and it was one of Europe's largest research institutes in the field of fertiliser.
Ownership
On 1 January 1960, Fisons Horticulture and Fisons Fertilisers were formed. The research site worked with both.
The horticultural division of Fisons was sold off for £25.4m in a management buy out in 1994 known as Levington Horticulture; the division had around 280 people and around 26% of the UK market, turning over £47m. In 1997 this division was sold on again to the present ownership.
Fertiliser
The research site developed the first specialist sports turf fertiliser; typical agricultural fertiliser was too concentrated: this is now found at all main golf courses across Europe under the Greensmaster brand. Levington Horticulture also made Turfclear herbicide, and had a Royal Warrant.
Compost
The site is known for developing Levington Compost in the 1960s. The compost was made in South Yorkshire and the fertiliser was made at Bramford, west of Ipswich, next to the Great Eastern Main Line.
Levington Multi-Purpose Compost (when owned by Fisons) had a 1984 television advert featuring Jack and the Beanstalk.
Visits
On Tuesday 1 May 1956, the site was visited by the Duke of Edinburgh.
Structure
It is in the Suffolk Coastal district of Suffolk.
See also
History of fertilizer
Sports Turf Research Institute
References
External links
History
1957 establishments in England
Chemical industry in the United Kingdom
Chemical research institutes
Horticultural organisations based in the United Kingdom
Research institutes established in 1957
Research institutes in Suffolk
East Suffolk (district) | Levington Research Station | [
"Chemistry"
] | 388 | [
"Chemical research institutes"
] |
55,885,346 | https://en.wikipedia.org/wiki/NGC%20499 | NGC 499, also occasionally referred to as PGC 5060, IC 1686 or GC 289, is a lenticular galaxy in the constellation Pisces. It is located approximately 197 million light-years from the Solar System and was discovered on 12 September, 1784 by astronomer William Herschel.
The NGC 499 Group is named after the galaxy.
Observation history
The object was discovered by Herschel along with NGC 495 and NGC 496. He initially described the discovery as "Three [NGC 499 along with NGC 495 and 496], eS and F, forming a triangle.". As he observed the trio again the next night, he was able to make out more detail: "Three, forming a [right triangle]; the [right angle] to the south NGC 499, the short leg preceding [NGC 496], the long towards the north [NGC 495]. Those in the legs [NGC 496 and 495] the faintest imaginable; that at the rectangle [NGC 499] a deal larger and brighter, but still very faint."
NGC 499 was later also observed by William Herschel's son John Herschel and independently found by Stéphane Javelle in 1899.
See also
Lenticular Galaxy
List of NGC objects (1–1000)
Pisces (constellation)
References
External links
SEDS
Lenticular galaxies
Pisces (constellation)
0499
IC objects
00926
005060
Astronomical objects discovered in 1784
Discoveries by William Herschel | NGC 499 | [
"Astronomy"
] | 307 | [
"Pisces (constellation)",
"Constellations"
] |
55,886,058 | https://en.wikipedia.org/wiki/Mobile%20Telecommunications%20Company%20of%20Esfahan | Mobile Telecommunication Company of Esfahan (شرکت مخابرات سیار اصفهان, Shirkat-e Mixabrat-e Siyar-e Esfehan, MTCE) also known as Espadan was a mobile network operator in Iran.
Following the agreements reached during the Iranian President Hashemi Rafsanjani's visit to Malaysia in 1994, and according to the laws of attracting and supporting foreign investment, in 29 May 2001 the license for launching the first prepaid mobile telephone network in Iran with an initial capacity of 20 thousand subscribers was granted to Celcom for 15 years, and the Malaysian Technology Resources Industry Company received permission to use GSM 24.18 Mbit/s bandwidth within the Isfahan province.
In 2005 Celcom sold its stakes to TM International(Telekom Malaysia).
In 2008 MTCE bought the WiMAX license from Iranian Communications Regulatory Authority (CRA).
In 2011 MTCE went broke and deactivated all sim cards following merger with Mobile Telecommunications Company of Iran.
Sim cards
Sim cards numbers had 0931 as prefix.
Shareholders
Axiata Group Berhad (49%) | Telecommunications Company of Esfahan (49%) | Iran Telecom Industries (2%)
References
Mobile technology
2001 establishments in Iran
Iranian companies established in 2001
Telecommunications companies established in 2001
Telecommunications companies of Iran
Mobile phone companies of Iran | Mobile Telecommunications Company of Esfahan | [
"Technology"
] | 288 | [
"nan"
] |
55,887,011 | https://en.wikipedia.org/wiki/Fecalith | A fecalith is a stone made of feces. It is a hardening of feces into lumps of varying size and may occur anywhere in the intestinal tract but is typically found in the colon. It is also called appendicolith when it occurs in the appendix and is sometimes concurrent with appendicitis. They can also obstruct diverticula. It can form secondary to fecal impaction. A fecaloma is a more severe form of fecal impaction, and a hardened fecaloma may be considered a giant fecalith. The term is from the Greek líthos=stone.
Diagnosis
CT scan
Projectional radiography
Ultrasound
Complications
A small fecalith is one cause of both appendicitis and acute diverticulitis.
See also
Bezoar
Fecal impaction, including fecaloma
Coprolith is also used to mean geologically fossilized feces.
References
External links
Diseases of appendix
Feces | Fecalith | [
"Biology"
] | 199 | [
"Feces",
"Excretion",
"Animal waste products"
] |
55,887,120 | https://en.wikipedia.org/wiki/NGC%205765 | NGC 5765, also designated as MCG+01-38-004 and MCG+01-38-005, is a pair of interacting megamasers in the constellation Virgo, roughly away from Earth. NGC 5765B is active, and energy is released from the core, some of which is absorbed by a nearby cloud of water. The cloud then re-emits this energy as microwaves. These emissions were used to help redefine the Hubble constant.
References
External links
Virgo (constellation)
Interacting galaxies
5765
09554 | NGC 5765 | [
"Astronomy"
] | 117 | [
"Virgo (constellation)",
"Galaxy stubs",
"Astronomy stubs",
"Constellations"
] |
55,887,304 | https://en.wikipedia.org/wiki/Frobenius%20formula | In mathematics, specifically in representation theory, the Frobenius formula, introduced by G. Frobenius, computes the characters of irreducible representations of the symmetric group Sn. Among the other applications, the formula can be used to derive the hook length formula.
Statement
Let be the character of an irreducible representation of the symmetric group corresponding to a partition of n: and . For each partition of n, let denote the conjugacy class in corresponding to it (cf. the example below), and let denote the number of times j appears in (so ). Then the Frobenius formula states that the constant value of on
is the coefficient of the monomial in the homogeneous polynomial in variables
where is the -th power sum.
Example: Take . Let and hence , , . If (), which corresponds to the class of the identity element, then is the coefficient of in
which is 2. Similarly, if (the class of a 3-cycle times an 1-cycle) and , then , given by
is −1.
For the identity representation, and . The character will be equal to the coefficient of in ,
which is 1 for any as expected.
Analogues
Arun Ram gives a q-analog of the Frobenius formula.
See also
Representation theory of symmetric groups
References
Macdonald, I. G. Symmetric functions and Hall polynomials. Second edition. Oxford Mathematical Monographs. Oxford Science Publications. The Clarendon Press, Oxford University Press, New York, 1995. x+475 pp.
Representation theory | Frobenius formula | [
"Mathematics"
] | 312 | [
"Representation theory",
"Fields of abstract algebra",
"Algebra stubs",
"Algebra"
] |
55,888,377 | https://en.wikipedia.org/wiki/NGC%204531 | NGC 4531 is a spiral galaxy located about 50 million light-years away in the constellation Virgo. It was discovered by astronomer William Herschel on April 17, 1784. NGC 4531 is a member of the Virgo Cluster.
See also
List of NGC objects (4001–5000)
NGC 4826
References
External links
Virgo (constellation)
Spiral galaxies
4531
41806
7729
Astronomical objects discovered in 1784
Virgo Cluster
Discoveries by William Herschel | NGC 4531 | [
"Astronomy"
] | 94 | [
"Virgo (constellation)",
"Constellations"
] |
55,890,020 | https://en.wikipedia.org/wiki/Niles%20Firebrick | Niles Firebrick was manufactured by the Niles Fire brick Company since it was created in 1872 by John Rhys Thomas until the company was sold in 1953 and completely shutdown in 1960. Capital to establish the company was provided by Lizzie B. Ward to construct a small plant across from the Old Ward Mill which was run by her husband James Ward. Thomas immigrated in 1868 from Carmarthenshire in Wales with his wife and son W. Aubrey Thomas who served as secretary of the company until he was appointed as representative to the U. S. Congress in 1904. The company was managed by another son, Thomas E. Thomas, after J.R. Thomas died unexpectedly in 1898. The Thomases returned the favor of their original capitalization by purchasing an iron blast furnace from James Ward when he went bankrupt in 1879. Using their knowledge of firebrick they were able to make this small furnace profitable. Later they used it to showcase the value of adding hot blast to a furnace using 3 ovens packed full of firebrick. The furnace was managed by another son, John Morgan Thomas.
Fire brick was first invented in 1822 by William Weston Young in the Vale of Neath in Wales, the county just east of Llanelli where the Thomas family lived before emigrating to Niles. It is recorded that Firebrick was made in the Llanelli area in 1870 but the market was highly cyclical and it was difficult to make a living at it.
From 1937 to 1941 the company worked to prevent the United Brick Workers Union (CIO) from organizing the workers in preference for an independent union favored by management. The CIO union prevailed. In spite of this episode the company had good relations with the employees and tried to keep them employed during economic downturns. The "Clingans" mentioned in that referenced interview were Margaret Thomas Clingan, a daughter and John Rhys Thomas Clingan, a grandson, who took over management of the Company when T.E. Thomas died in 1920.
Patrick J. Sheehan worked various jobs at Niles Fire Brick Company from age 13 up until 1897 when he was appointed superintendent of the plant. When Sheehan started with the company they occupied a plant covering a floor space of 3,600 square feet, two kilns, and the output was 640,000 bricks per year. The plant was moved to Langley street eighteen months afterward, and the output increased to 1,200,000. This Langley street works has constantly added to each year, until the output was 6 million, and in 1905 they built the "Falcon" plant on the site formerly occupied by the Langley street plant, which doubled production to 12 million per year. By 1955 the output was 25 million. The work of molding and firing brick was highly labor-intensive. Immigrants from Southern States and European countries, especially Italy, were sought to perform labor under difficult working conditions.
An article in the March-April "The Niles Register" of the Niles Historical Society discusses the history of the headquarters of the company at 216 Langely Street with a pattern shop in the back where skilled workers created the molds for custom bricks ordered by the mills in the 1902- 1912 period. After that the pattern shop was used by the Sons of Italy and later by the Bagnoli-Irpino Club. This was a result of the large percentage of immigrants from the Bagnoli-Irpino area in Italy. One of the founders of the club was Lawrence Pallante, an early immigrant from that area and presumably an ancestor of the reference articles. Immigration from that area began in 1880 and extended to about 1960.
References
Refractory materials
Silicates
Bricks
Niles, Ohio | Niles Firebrick | [
"Physics"
] | 746 | [
"Refractory materials",
"Materials",
"Matter"
] |
55,890,421 | https://en.wikipedia.org/wiki/Philasterides%20dicentrarchi | Philasterides dicentrarchi is a marine protozoan ciliate that was first identified in 1995 after being isolated from infected European sea bass (Dicentrarchus labrax) reared in France. The species was also identified as the causative agent of outbreaks of scuticociliatosis that occurred between summer 1999 and spring 2000 in turbot (Scophthalmus maximus) cultivated in the Atlantic Ocean (Galicia, Northwest Spain). Infections caused by P. dicentrarchi have since been observed in turbot reared in both open flow and recirculating production systems. In addition, the ciliate has also been reported to cause infections in other flatfishes, such as the olive flounder (Paralichthys olivaceus) in Korea and the fine flounder (Paralichthys adspersus) in Peru, as well as in seadragons (Phyllopteryx taeniolatus and Phycodurus eques), seahorses (Hippocampus kuda and H. abdominalis), and several species of sharks in other parts of the world.
Biology and pathology
P. dicentrarchi is included within the subclass Scuticociliatia, which includes about 20 species of ciliates that are typically microphagous bacteriovores and generally abundant in eutrophic habitats in lakes and in coastal marine habitats. Some of these ciliates, characterized by possessing a scutica (a transient kinetosomal structure that is present during stomatogenesis), can behave as endoparasites and are capable of producing serious infections in a wide variety of vertebrates, especially fish, and invertebrates such as crustaceans and echinoderms. P. dicentrarchi is a microaerophilic scuticociliate that lives at the sea bottom, at or below the oxycline or on the monimolimnion, where it feeds on bacteria. However, when it encounters a host it can also behave as an opportunistic histiophagous parasite. Survival of the species inside the host and adaptation to a parasitic lifestyle are attributed to the existence of physiological adaptations at the level of mitochondrial metabolism. Such adaptations include the presence of a second terminal oxidase (which enables the ciliates to obtain energy and survive low levels of oxygen), antioxidant enzymes, inorganic pyrophosphatases (capable of producing energy by an ATP alternative pathway produced during oxidative metabolism) and the ability of the species to survive in hyposaline environments. Although the route of entry to the host is unknown, the findings of experimental infection studies suggest that the ciliate probably gains access through lesions in the gills and/or the skin. Infected fish show haemorrhagic ulcers on the skin (particularly around the operculum), abundant ascitic fluid in the abdominal cavity, uni- or bilateral exophthalmia, and systemic infection with the presence of ciliates in blood, gills, gastrointestinal tract, liver, spleen, kidneys and musculature. In the final phase of infection, ciliates reach the brain and cause softening and liquefaction of the tissue.
Diagnosis
Diagnosis of P. dicentrarchi in the sea bass and the turbot was initially based primarily on morphological characteristics associated with the oral apparatus and the number of kineties. However, it has been suggested that the combined use of morphological, biological, molecular and serological techniques is necessary for correct identification of the species. P. dicentrarchi was previously considered a junior synonym of Miamiensis avidus. However, recent physiological and molecular studies have shown that P. dicentrarchi and M. avidus strain Ma/2 -ATCC 50180™- are different species.
Treatments
No effective chemotherapeutic measures have been developed for controlling scuticociliatosis in the acute phase of the disease to date. However, the addition of disinfectants such as formalin, hydrogen peroxide and Jenoclean (a mixture of Atacama extract 97%-Zeolites- and citric acid 3%) to seawater has been demonstrated to kill the ciliates. Bath treatments consisting of a combination of benzalkonium chloride and bronopol have also proved to be effective in reducing fish mortality. Several compounds of well-known antiprotozoal activity, including niclosamide, oxyclozanide, bithionol sulfoxide, toltrazuril, N-(2 '-hydroxy-5 '-chloro-benzoyl) 2-chloro-4-nitroaniline, BP68, doxycycline hyclate, albendazole, carnidazole, pyrimethamine, hydrochloride quinacrine and quinine sulphate, are also active against P. dicentrarchi. Antimalarial drugs such as chloroquine and artemisinin also inhibit the in vitro growth of P. dicentrarchi. Other studies investigating the in vitro effects of several new synthetic compounds, including 2 naphthyridines, 2 pyridothienodiazines and 13 pyridothienotriazines, have demonstrated that all display parasiticide activity, and that pyridothienotriazine (12k) was the most active. In addition, several compounds of natural origin have also shown in vitro antiparasitic activity: the polyphenols mangiferin and (–)-epigallocatechin-3-gallate (EGCG), curcumin, resveratrol and the synthetic polyphenol propyl gallate.
Prevention
Vaccines containing trophozoites inactivated with formalin and prepared in oil adjuvants have been developed and have shown good protection against the homologous serotype. Several P. dicentrarchi serotypes have been described. However, the protection induced against heterologous isolates appears to be very low or non-existent.
Research
Research on Philasterides dicentrarchi, which includes aspects of cell biology, diagnostics, interactions with the host immune system, search for new treatments, development of vaccines or risk analysis, is being carried out under the EU funded Horizon2020 Project ParaFishControl.
References
Philasterida
Ciliate species
Parasitic eukaryotes
Parasites of fish | Philasterides dicentrarchi | [
"Biology"
] | 1,370 | [
"Parasitic eukaryotes",
"Eukaryotes"
] |
55,891,573 | https://en.wikipedia.org/wiki/SHIFT%20Inc. | is a Japanese software testing company, headquartered in Tokyo, that provides software quality assurance and software testing solutions.
Overview
SHIFT Inc. was founded in 2005 by Masaru Tange, who was a manufacturing process improvement consultant.
In the earliest years, it was a tiny consulting company specializing in manufacturing and business process improvements. In 2007, it entered the software testing industry by undertaking consultancy work for the improvement of E-commerce testing. In 2009, Tange changed the company's direction from the process improvement consultancy to the software testing business. The company then grew so rapidly to be listed on the Tokyo Stock Exchange Mothers market in 2014. In April 2020, it has the market capitalization of 143 billion yen ($1.3 billion), which is the largest of the listed Japanese companies specialized in software quality assurance and testing services.
The company covers software testing outsourcing, project management office and test strategy planning supports, test execution, test design, automated testing, software inspection, and educational program services.
Notes
References
External links
SHIFT Inc.
Software companies of Japan
Service companies based in Tokyo
Software testing
Companies listed on the Tokyo Stock Exchange
Japanese companies established in 2005
Software companies established in 2005 | SHIFT Inc. | [
"Engineering"
] | 237 | [
"Software engineering",
"Software testing"
] |
55,894,376 | https://en.wikipedia.org/wiki/Valley%20of%20the%20Boom | Valley of the Boom (stylized as Valley_of_the_BOOM) is an American docudrama television miniseries created by Matthew Carnahan that premiered on January 13, 2019, on National Geographic. The series centers on the 1990s tech boom and bust in Silicon Valley and it stars Bradley Whitford, Steve Zahn, Lamorne Morris, John Karna, Dakota Shapiro, Oliver Cooper, and John Murphy.
Premise
Valley of the Boom takes a close look at "the culture of speculation, innovation and debauchery that led to the rapid inflation and burst of the 1990s tech bubble. As with its hybrid series Mars, Nat Geo [uses] select doc elements to support the scripted drama to tell the true inside story of the dramatic early days of Silicon Valley."
The series features interviews with many of the people depicted in the dramatized portions of the production in addition to other Internet personalities such as Mark Cuban and Arianna Huffington. Notably absent from these interviews are Netscape co-founder and former vice president of technology Marc Andreessen, who declined to be interviewed, and Jamie Zawinski.
Although the program is primarily focused on the quick rise and fall of three influential technology companies, namely Netscape, theGlobe.com, and Pixelon, the program also highlights smaller companies of that era, such as sfGirl.com.
Cast and characters
Main
Bradley Whitford as James L. Barksdale
Lamorne Morris as Darrin Morris
Oliver Cooper as Todd Krizelman
John Karna as Marc Andreessen
Dakota Shapiro as Stephan Paternot
John Murphy as Jim Clark
Steve Zahn as Michael Fenne
Recurring
Raf Rogers as Sean Alvaro
Chiara Zanni as Sheila
Fred Henderson as Mike Egan
Camille Hollett-French as Tara Hernandez
Mike Kovac as Balding Ponytail Coder
Nick Hunnings as Ed Cespedes
Tom Stevens as Phillip
Siobhan Williams as Jenn
Vincent Dangerfield as Lee Wiskowski
Jacob Richter as Dan Goodin
Hilary Jardine as Patty Beron
Paul Herbert as Paul Ward
Carey Feehan as Robert Dunning
Donna Benedicto as Kate
Guest
Keegan Connor Tracy as Rosanne Siino ("Part 1: print ("hello, world")")
Luvia Petersen as Mary Meeker ("Part 1: print ("hello, world")")
Michael Patrick Denis as Thomas Reardon ("Part 2: pseudocode")
Jesse James as Barry Moore ("Part 4: priority inversion")
Siobhan Williams as Jenn ("Part 4: priority inversion")
Doug Abrahams as Ace Greenberg ("Part 4: priority inversion")
David Stuart as Pit Boss ("Part 4: priority inversion")
Connor Tracy as Rosanne Siino ("Part 5: segfault")
Rachel Hayward as Joyce ("Part 5: segfault")
Tom Stevens as Phillip ("Part 6: fatal error")
Episodes
Production
Development
On November 15, 2017, it was announced that National Geographic had given the production a series order consisting of six episodes. Executive producers included Matthew Carnahan, Arianna Huffington, Jason Goldberg, Brant Pinvidic, and David Walpert. Carnahan acted as showrunner for the series and directed as well. David Newsom was co-executive producer and led the non-scripted unit of the production. Joel Ehninger acted in the role of producer. Production companies involved with the series included STXtelevision and Matthew Carnahan Circus Products. On September 24, 2018, it was announced that the series would premiere on January 13, 2019.
Casting
On March 16, 2018, it was announced that Bradley Whitford, Steve Zahn, Lamorne Morris, John Karna, Dakota Shapiro, and Oliver Cooper had joined the series' main cast.
Filming
Principal photography for the series began on March 26, 2018 in Vancouver, Canada and was expected to conclude by May 28, 2018.
Release
Marketing
On July 24, 2018, the first trailer for the series was released.
Premiere
On September 21, 2018, the series held its world premiere during the second annual Tribeca TV Festival in New York City. Following a screening, a conversation took place featuring members of the cast and crew including creator Matthew Carnahan, actors Bradley Whitford, Steve Zahn, Lamorne Morris, and real-life subject Stephan Paternot, founder of theGlobe.com.
Distribution
The series premiered globally on National Geographic in 171 countries and 45 languages. STXtelevision distributes the series in China.
Reception
The series has been met with a mixed response from critics upon its premiere. On the review aggregation website Rotten Tomatoes, the series holds a 72% approval rating with an average rating of 5.90 out of 10 based on 18 reviews. The website's critical consensus reads, "A visual collage of dot com history, Valley of Boom proves to be just as sprawling and ramshackle as the docuseries' subject." Metacritic, which uses a weighted average, assigned the series a score of 58 out of 100 based on 11 critics, indicating "mixed or average reviews".
Notes
References
External links
2019 American television series debuts
2019 American television series endings
Documentary television series about computing
American English-language television shows
National Geographic (American TV channel) original programming
Nerd culture
Science docudramas | Valley of the Boom | [
"Technology"
] | 1,079 | [
"Works about computing",
"Documentary television series about computing"
] |
55,895,027 | https://en.wikipedia.org/wiki/Disposable%20soma%20theory%20of%20aging | In biogerontology, the disposable soma theory of aging states that organisms age due to an evolutionary trade-off between growth, reproduction, and DNA repair maintenance. Formulated by British biologist Thomas Kirkwood, the disposable soma theory explains that an organism only has a limited amount of resources that it can allocate to its various cellular processes. Therefore, a greater investment in growth and reproduction would result in reduced investment in DNA repair maintenance, leading to increased cellular damage, shortened telomeres, accumulation of mutations, compromised stem cells, and ultimately, senescence. Although many models, both animal and human, have appeared to support this theory, parts of it are still controversial.
Specifically, while the evolutionary trade-off between growth and aging has been well established, the relationship between reproduction and aging is still without scientific consensus, and the cellular mechanisms largely undiscovered.
Background and history
British biologist Thomas Kirkwood first proposed the disposable soma theory of aging in a 1977 Nature review article. The theory was inspired by Leslie Orgel's Error Catastrophe Theory of Aging, which was published fourteen years earlier, in 1963. Orgel believed that the process of aging arose due to mutations acquired during the replication process, and Kirkwood developed the disposable soma theory in order to mediate Orgel's work with evolutionary genetics.
Principles
The disposable soma theory of aging posits that there is a trade-off in resource allocation between somatic maintenance and reproductive investment. Too low an investment in self-repair would be evolutionarily unsound, as the organism would likely die before reproductive age. However, too high an investment in self-repair would also be evolutionarily unsound due to the fact that one's offspring would likely die before reproductive age. Therefore, there is a compromise and resources are partitioned accordingly. However, this compromise is thought to damage somatic repair systems, which can lead to progressive cellular damage and senescence. Repair costs can be categorized into three groups: (1) the costs of increased durability of nonrenewable parts; (2) the costs of maintenance involving cell renewal, and (3) the costs of intracellular maintenance. In a nutshell, aging and decline is essentially a trade-off for increased reproductive robustness in youth.
Mechanisms
Growth and somatic maintenance
Much research has been done on the antagonistic effects of increased growth on lifespan. Specifically, the hormone insulin-like growth factor 1 (IGF-1), binds to a cell receptor, leading to a phosphorylation cascade. This cascade results in kinases phosphorylating forkhead transcription factor (FOXO), deactivating it. Deactivation of FOXO results in an inability to express genes involved in responding to oxidative stress response, such as antioxidants, chaperones, and heat-shock proteins.
Additionally, uptake of IGF-1 stimulates the mTOR pathway, which activates protein synthesis (and therefore growth) through upregulation of the translation-promoting S6K1, and also inhibits autophagy, a process necessary for recycling of damaged cellular products. Decline of autophagy causes neurodegeneration, protein aggregation and premature aging. Lastly, studies have also indicated that the mTOR pathway also alters immune responses and stimulates cyclin-dependent kinase (CDK) inhibitors such as p16 and p21. This leads to alteration of the stem-cell niche and results in stem cell exhaustion, another theorized mechanism of aging.
Reproduction and somatic maintenance
While reproduction inhibits lifespan with regard to multicellular organisms, the precise mechanism responsible for this effect remains unclear. Although many models do illustrate an inverse relationship, and the theory makes sense from an evolutionary perspective, the cellular mechanisms have yet to be explored. However, with regards to cellular replication, the progressive shortening of telomeres is a mechanism which limits the amount of generations of a single cell may undergo. Furthermore, in unicellular organisms like Saccharomyces cerevisiae, the formation of extrachromosomal rDNA circles (ERCs) in mother cells (but not daughter cells) upon every subsequent division is an identifiable type of DNA damage that is associated with replication. These ERCs accumulate over time and eventually trigger replicative senescence and death of the mother cell.
Evidence
Growth and aging
There is a large body of evidence indicating the negative effects of growth on longevity across many species. As a general rule, individuals of a smaller size generally live longer than larger individuals of the same species.
Animal models
In dwarf models of mice, such Snell or Ames mice, mutations have arisen, either rendering them incapable of producing IGF-1 or unable to have adequate receptors for IGF-1 uptake. Furthermore, mice injected with growth hormone have been shown to have progressive weight loss, roughing of the coat, curvature of the spine, enlargement of the organs, kidney lesions and increased cancer risk. This effect is also seen in different breeds of dogs, where smaller breeds of dogs typically live significantly longer compared to their larger counterparts. Selectively bred for their small size, smaller dog breeds like the Chihuahua (average lifespan of 15–20 years) have the B/B genotype for the IGF-1 haplotype, reducing the amount of IGF-1 produced. Conversely, large dogs like the Great Dane (average lifespan of 6–8 years) are homozygous for the IGF-1 I allele, which increases the amount of IGF-1 production.
Human models
Initially, it was believed that growth hormone actually prolonged lifespan due to a 1990 study that indicated that injection of growth hormone to men over 60 years of age appeared to reverse various biomarkers implicated in aging, such as decreased muscle mass, bone density, skin thickness, and increased adipose tissue. However, a 1999 study found that administering growth hormone also significantly increased mortality rate. Recent genomic studies have confirmed that the genes involved in growth hormone uptake and signaling are largely conserved across a plethora of species, such as yeast, nematodes, fruit flies, mice and humans. These studies have also shown that individuals with Laron syndrome, an autosomal recessive disorder resulting in dwarfism due to defects in growth hormone receptors, have increased lifespan. Additionally, these individuals have much lower incidences of age-related diseases such as type 2 diabetes and cancer. Lastly, human centenarians around the world are disproportionately of short stature, and have low levels of IGF-1.
Reproduction and aging
Numerous studies have found that lifespan is inversely correlated with both the total amount of offspring birthed, as well as the age at which females first gives birth, also known as primiparity. Additionally, it has been found that reproduction is a costly mechanism that alters the metabolism of fat. Lipids invested in reproduction would be unable to be allocated to support mechanisms involved in somatic maintenance.
Animal models
The disposable soma theory has been consistent with the majority of animal models. It was found in numerous animal studies that castration or genetic deformities of reproduction organs was correlated with increased lifespan. Moreover, in red squirrels, it was found that females with an early primiparity achieved the highest immediate and lifetime reproductive success. However, it was also found that these same individuals had a decreased median and maximum lifespan. Specifically squirrels who mated earlier had a 22.4% rate of mortality until two years of age compared to a 16.5% rate of mortality in late breeders. In addition, these squirrels had an average maximum lifespan of 1035 days compared to an average maximum lifespan of 1245 days for squirrels that bred later.
In another study, researchers selectively bred fruit flies over three years to develop two different strains, an early-reproducing strain and a late-reproducing strain. The late-reproducing line had a significantly longer lifespan than the early-reproducing line. Even more telling was that when the researchers introduced a mutation in the ovarian-associated gene ovoD1, resulting in defective oogenesis, the differences in lifespan between the two lines disappeared. The researchers in this case concluded that "aging has evolved primarily because of the damaging effects of reproduction earlier in life".
Prominent aging researcher Steven Austad also performed a large-scale ecological study on the coast of Georgia in 1993. Austad isolated two opossum populations, one from the predator-infested mainland and one from the predator-absent nearby island of Sapelo. According to the disposable soma theory, a genetically isolated population subject to low environmentally-induced mortality would evolve delayed reproduction and aging. This is because without the pressure of predation, it would be evolutionarily advantageous to allocate more resources to somatic maintenance than reproduction, as early offspring mortality would be low. As predicted, even after controlling for predation, the isolated population had a longer lifespan, delayed primiparity, and reduced aging biomarkers such as tail collagen cross-linking.
Human models
In general, only a few studies exist in human models. It was found that castrated men live longer than their fertile counterparts. Further studies found that in British women, primiparity was earliest in women who died early and latest in women who died at the oldest ages. Furthermore, increased number of children birthed was associated with a decreased lifespan. A final study found that female centenarians were more likely to have children in later life compared to the average, especially past the age of 40. The researchers discovered that 19.2% of female centenarians had their first child after the age of 40, compared to 5.5% of the rest of the female population.
Relationship between cell damage and aging
There are numerous studies that support cellular damage, often due to a lack of somatic maintenance mechanisms, as a primary determinant for aging, and these studies have given rise to the free radical theory of aging and the DNA damage theory of aging. One study found that the cells of short-living rodents in vitro show much greater mutation rates and a general lack of genome surveillance compared to human cells and are far more susceptible to oxidative stress.
Other studies have been conducted on the naked mole rat, a rodent species with remarkable longevity (30 years), capable of outliving the brown rat (3 years) by ten-fold. Additionally, almost no incidence of cancer has ever been detected in naked mole rats. Nearly all of the differences found between these two organisms, which are otherwise rather genetically similar, was in somatic maintenance. Naked mole rats were found to have higher levels of superoxide dismutase, a reactive oxygen species clearing antioxidant. In addition, naked mole rats had higher levels of base excision repair, DNA damage response signaling, homologous recombination repair, mismatch repair, nucleotide excision repair, and non-homologous end joining. In fact, many of these processes were near or exceeded human levels. Proteins from naked mole rats were also more resistant to oxidation, misfolding, ubiquitination, and had increased translational fidelity.
Further studies have been conducted on patients with Hutchinson-Gilford Progeria Syndrome (HGPS), a condition that leads to premature aging. Patients with HGPS typically age about seven times faster than average and usually succumb to the disease in their early teens. Patients with HGPS have cellular defects, specifically in the lamin proteins, which regulate the organization of the lamina and nuclear envelope for mitosis. A-type lamins promote genetic stability by maintaining levels of proteins that have key roles in the repair processes of non-homologous end joining and homologous recombination. Mouse cells deficient for maturation of prelamin A show increased DNA damage and chromosome aberrations and have increased sensitivity to DNA damaging agents.
Lastly, as mentioned previously, it has been found that the suppression of autophagy is associated with reduced lifespan, while stimulation is associated with extended lifespan. Activated in times of caloric restriction, autophagy is a process that prevents cellular damage through clearance and recycling of damaged proteins and organelles.
Criticism
One of the main weaknesses of the disposable soma theory is that it does not postulate any specific cellular mechanisms to which an organism shifts energy to somatic repair over reproduction. Instead, it only offers an evolutionary perspective on why aging may occur due to reproduction. Therefore, parts of it are rather limited outside of the field of evolutionary biology.
Caloric restriction
Critics have pointed out the supposed inconsistencies of the disposable soma theory due to the observed effects of caloric restriction, which is correlated with increased lifespan. Although it activates autophagy, according to classical disposable soma principles, with less caloric intake, there would less total energy to be distributed towards somatic maintenance, and decreased lifespan would be observed (or at least the positive autophagic effects would be balanced out). However, Kirkwood, alongside his collaborator Darryl P. Shanley, assert that caloric restriction triggers an adaptive mechanism which causes the organism to shift a higher proportion of resources to somatic maintenance, away from reproduction. This theory is supported by multiple studies, which show that caloric restriction typically results in impaired fertility, but leave an otherwise healthy organism. Evolutionarily, an organism would want to delay reproduction to when resources were more plentiful. During a resource-barren period, it would evolutionarily unwise to invest resources in progeny that would be unlikely to survive in famine. Mechanistically, the NAD-dependent deacetylase Sirtuin 1 (SIRT-1) is upregulated during low-nutrient periods. SIRT-1 increases insulin sensitivity, decreases the amount of inflammatory cytokines, stimulates autophagy, and activates FOXO, the aforementioned protein involved in activating stress response genes. SIRT-1 is also found to result in decreased fertility.
In additional to differential partitioning of energy allocation during caloric restriction, less caloric intake would result in less metabolic waste in the forms of free radicals like hydrogen peroxide, superoxide and hydroxyl radicals, which damage important cellular components, particularly mitochondria. Elevated levels of free radicals in mice has been correlated with neurodegeneration, myocardial injury, severe anemia, and premature death.
No changes were observed in the spontaneous chromosomal mutation frequency of dietary restricted mice (aged 6 and 12 months) compared to ad libitum fed control mice. Thus dietary restriction appears to have no appreciable effect on spontaneous mutation in chromosomal DNA, and the increased longevity of dietary restricted mice apparently is not attributable to reduced chromosomal mutation frequency.
The grandmother hypothesis
Another primary criticism of the disposable soma theory is that it fails to account for why women tend to live longer than their male counterparts. After all, females invest significantly more resources into reproduction and according to the classical disposable soma principles, this would compromise energy diverted to somatic maintenance. However, this can be reconciled with the grandmother hypothesis. The Grandmother Hypothesis states that menopause comes about into older women in order to restrict the time of reproduction as a protective mechanism. This would allow women to live longer and increase the amount of care they could provide to their grandchildren, increasing their evolutionary fitness. And so, although women do invest a greater proportion of resources into reproduction during their fertile years, their overall reproductive period is significantly shorter than men, who are able of reproduction during and even beyond middle age. Additionally, males invest more resources into growth compare to females, which is correlated with decreased lifespan. Other variables such as increased testosterone levels in males are not accounted for. Increased testosterone is often associated with reckless behaviour, which may lead to a high accidental death rate.
Contradicting models
A few contradicting animal models weaken the validity of the disposable soma theory. This includes studies done on the aforementioned naked mole rats. In these studies, it was found that reproductive naked mole rats actually show significantly increased lifespans compared to non-reproductive individuals, which contradicts the principles of disposable soma. However, although these naked mole rats are mammalian, they are highly atypical in terms of aging studies and may not serve as the best model for humans. For example, naked mole rats have a disproportionately high longevity quotient and live in eusocial societies, where breeding is usually designated to a queen.
Sex biases and environment
The disposable soma theory is tested disproportionately on female organisms for the relationship between reproduction and aging, as females carry a greater burden in reproduction. Additionally, for the relationship between growth and aging, studies are disproportionately conducted on males, to minimize the hormonal fluctuations that occur with menstrual cycling. Lastly, genetic and environmental factors, rather than reproductive patterns, may explain the variations in human lifespan. For example, studies have shown that poorer individuals, to whom nutritious food and medical care is less accessible, typically have higher birth rates and earlier primiparity.
References
External links
Calorie restriction
Calorie Restriction Society
Biology of aging
Damage-Based Theories of Aging—Includes a discussion of the free radical theory of aging
Evolution
Proximate theories of biological ageing
Senescence
Theories of ageing
Theories of biological ageing | Disposable soma theory of aging | [
"Chemistry",
"Biology"
] | 3,622 | [
"Free radicals",
"Senescence",
"Cellular processes",
"Biomolecules",
"Theories of biological ageing",
"Metabolism"
] |
44,265,248 | https://en.wikipedia.org/wiki/VSS%20Enterprise%20crash | The VSS Enterprise crash occurred on October 31, 2014, when the VSS Enterprise, a SpaceShipTwo experimental spaceflight test vehicle operated by Virgin Galactic, suffered a catastrophic in-flight breakup during a test flight and crashed in the Mojave Desert near Cantil, California. Co-pilot Michael Alsbury was killed and pilot Peter Siebold was seriously injured.
The National Transportation Safety Board later concluded that the breakup was caused by Alsbury's premature unlocking of the air brake device used for atmospheric re-entry. The NTSB said other important factors in the accident were inadequate design safeguards, poor pilot training and lack of rigorous oversight by the Federal Aviation Administration (FAA).
Accident
On the day of the accident, Enterprise was performing a test flight – powered flight 4 (PF04) – in which it was dropped from the WhiteKnightTwo carrier aircraft, VMS Eve, after taking off from the Mojave Air and Space Port. The test flight was the aircraft's first powered flight in nine months, and was to include the first flight testing of a new, more powerful and steadier-thrust hybrid rocket engine whose fuel grain was composed of nylon instead of rubber. The flight was the aircraft's 55th, and its 35th free flight. VSS Enterprise was crewed by pilot Peter Siebold and co-pilot Michael Alsbury.
According to the NTSB briefing, SpaceShipTwo (SS2) dropped from the mother ship as planned and fired its new hybrid rocket engine normally. About eleven seconds later, the space plane violently broke apart, substantially giving the appearance of an explosion, and creating a debris field. Witnesses reported seeing a parachute before the aircraft crashed. Alsbury was killed in the crash. Siebold survived with serious injuries and was transported to Antelope Valley Hospital in nearby Lancaster. The carrier aircraft, VMS Eve, landed safely.
There was initial conjecture from some industry experts that the new rocket engine was at fault, but this was quickly disproved when the craft's engine and propellant tanks were recovered intact; indicating there was no explosion due to either the solid (nylon-based) or liquid (nitrous oxide) components of the hybrid engine.
A preliminary investigation and cockpit video subsequently indicated that the feathering system, the ship's air-braking descent device, deployed too early. Two seconds later, while still under rocket propulsion, the craft disintegrated. The feathering system requires two levers to operate. The system was unlocked by Michael Alsbury, but the feathering control was not moved, indicating an uncommanded feathering as "that action alone should not have been enough to pivot the tails upright" according to the NTSB. The feathering system had been deliberately deployed at supersonic speeds during earlier powered flight tests of SS2, but previous activation either occurred in thinner air at higher altitudes, or at much lower speeds than the flight on October 31.
Regarding the possibility of pilot error being the proximate cause of the crash, acting NTSB chairman Christopher Hart said: "We are not ruling anything out. We are looking at all of these issues to determine what was the root cause of this mishap … We are looking at a number of possibilities, including that possibility (of pilot error)."
The incident resulted in the first fatality on a spacecraft in flight since the Space Shuttle Columbia disaster in 2003. The survival of pilot Peter Siebold also marks the first time in history that anyone has survived the destruction of a spacecraft during a flight when others on board have died. Investigators were initially puzzled about how Siebold managed to get out of the rocket plane and parachute to the ground from an altitude of roughly , where the atmosphere is virtually devoid of oxygen. On November 7, Siebold told investigators that the aircraft broke up around him. He was still strapped into his seat. He released the straps and his parachute later deployed automatically. Siebold was not wearing a pressure suit.
Aircraft
The vehicle in the accident, VSS Enterprise, registration N339SS, was the sole Scaled Composites Model 339 SpaceShipTwo test vehicle. It was the first of the five SpaceShipTwo craft planned by Virgin Galactic. Since October 2010, VSS Enterprise had flown 20 captive flights while remaining attached to its WhiteKnightTwo carrier aircraft, 31 unpowered glide-to-landing tests, and three rocket-powered test flights. There were several performance issues during the ship engine's development in 2012 and 2013.
A rocket-powered test flight of SpaceShipTwo took place on April 29, 2013, with an engine burn of 16 seconds duration. The brief flight began at an altitude of , and reached a maximum altitude of and a speed of Mach 1.2 ().
A second SS2 vehicle, VSS Unity, was rolled out in February 2016.
Investigation
The National Transportation Safety Board (NTSB) investigated the accident. A Go Team was dispatched to the accident site on October 31, 2014. The team, consisting of around fifteen personnel, arrived at the Mojave Air and Space Port on November 1. They began their investigation that day.
At a news conference on November 2, NTSB acting chairman Christopher Hart said the lock–unlock lever for the vehicle's feathering mechanism was moved to the unlocked position at slightly above Mach 1. SpaceShipTwo's feathering mechanism then began moving even though that motion had not been commanded. The on-site investigation was scheduled to take four to seven days. It was reported on November 12 that the on-site investigation had been completed and that parts of the wreckage had been placed in secure storage should they be needed for further investigation. It was expected to take about a year for the final report to be released.
During a hearing in Washington D.C. on July 28, 2015, and a press release on the same day, the NTSB cited inadequate design safeguards, poor pilot training, lack of rigorous federal oversight and a potentially anxious co-pilot without recent flight experience as important factors in the 2014 crash. They determined that the co-pilot, who died in the accident, prematurely unlocked a movable tail section some ten seconds after SpaceShipTwo fired its rocket engine and was breaking the sound barrier, resulting in the craft breaking apart. The Board also found that the Scaled Composites unit of Northrop Grumman, which designed and flew the prototype space tourism vehicle, did not properly prepare for potential human slip-ups by providing a fail-safe system that could have guarded against such premature deployment. "A single-point human failure has to be anticipated," board member Robert Sumwalt said. Instead, Scaled Composites "put all their eggs in the basket of the pilots doing it correctly."
The report's details of the final moments of the flight reveal that the feather system was unlocked as SS2 accelerated under rocket power through Mach 0.92 at 10.07:28, 9 seconds after release from the WhiteKnightTwo (WK2) carrier aircraft and 14 seconds before the vehicle would have reached Mach 1.4, the minimum speed at which the tail was designed to be unlocked. Telemetry, in-cockpit video and audio data confirmed that co-pilot Michael Alsbury announced "unlocking" as Mach 0.92 was passed and vehicle breakup occurred within the next 4 seconds. The feathering device, conceived by Scaled Composites designer Burt Rutan, is deployed after reaching maximum altitude, increasing drag and slowing descent as a carefree and stable reentry method for recovery of SpaceShipOne. The system operates by rotating the vehicle's twin tail booms upward about the trailing edge of the wing by around 65 degrees; following reentry, the actuators rotate the booms down into the flush position for approach and landing. Aerodynamic forces when accelerating through the transonic moments of the flight, above Mach 0.85 and below Mach 1.34, push upwards on the tail; releasing the locks before the vehicle passes these speeds means that a pair of actuators were the only things keeping the tail in place against these powerful forces, which had unintentionally been sufficient on earlier test flights.
Investigators said the developer of the spacecraft failed to include systems to protect against human error, believing that highly trained test pilots were simply incapable of making a wrong move, and that co-pilot Michael Alsbury may have been influenced by time pressure, along with strong vibration and acceleration forces he had not experienced since his last powered test flight in April 2013. The combination "could have increased the co-pilot's stress." The board found that during years of development and flight tests, engineers at Scaled Composites assumed that any pilot mistakes would occur only in reaction to systems failures, not as the cause of such failures. The Flight Test Data Card for this mission, giving information on the test vehicle and the step-by-step mission plan, called for the feathering system to be unlocked at Mach 1.4, but did not indicate that unlocking early could be a danger. The NTSB investigators also found just one email, from 2010, and one presentation slide, from 2011, that even mentioned the risks of unlocking before completing the transonic stage of the acceleration. The NTSB members also criticized the FAA, which approved the experimental test flights, for failing to pay enough attention to human factors or to provide necessary guidance to the nascent commercial space flight industry on the topic. They also cited pressure from some FAA managers to quickly approve experimental flight permits, sometimes without fully understanding technical issues or the details of the spacecraft.
In its submission to the NTSB, Virgin Galactic says the second SS2, nearing completion, had been modified with an automatic mechanical inhibit device to prevent locking or unlocking of the feather during safety-critical phases. An explicit warning about the dangers of premature unlocking has also been added to the checklist and operating handbook, and a formalized crew resource management (CRM) approach, already used by Virgin for its WK2 operations, is being adopted for SS2. This will include call-outs and a challenge/response protocol. While the report cites CRM issues as a likely contributing cause, Virgin says there is no plan to modify the cockpit display system.
NTSB chairman Christopher Hart said that, as the Board had learned "with a high degree of certainty the events that resulted in the breakup", he hoped the investigation would prevent such an accident from happening again. "Many of the safety issues that we will hear about today arose not from the novelty of a space launch test flight, but from human factors that were already known elsewhere in transportation." Hart added "for commercial spaceflight to successfully mature, we must meticulously seek out and mitigate known hazards, as a prerequisite to identifying and mitigating new hazards." Virgin Galactic is proceeding with its plans for space flight and is building another craft; company officials said that their commitment to commercial spacecraft had not wavered despite the crash and they expected the company to resume test flights later in 2015, though that date subsequently slipped. On 19 February 2016, Enterprise'''s successor, VSS Unity, was unveiled by Scaled Composites and Virgin Galactic.
Responses
Virgin Galactic CEO George T. Whitesides, in a news conference following the incident, said that "Space is hard and today was a tough day." Virgin founder Richard Branson said after the crash: "We do understand the risks involved and we are not going to push on blindly—to do so would be an insult to all those affected by this tragedy. We are going to learn from what went wrong, discover how we can improve safety and performance and then move forwards together," and "Space is hard, but worth it."
Michael Moses, Head of Operations for Virgin Galactic, admitted to tensions between Richard Branson's upbeat projections and the persistent hurdles that challenged the company's technical experts. "There's a difference between the marketing and the engineering sides of the company", Mr. Moses said on November 10, 2014.
The International Association for the Advancement of Space Safety (IAASS) heavily criticized Virgin Galactic within hours of the accident. Tommaso Sgobba, Executive Director of the IAASS, claimed that Virgin Galactic had refused to let IAASS scientists review its procedures and snubbed industry gatherings. He stated: "They operated in secrecy, which is difficult to understand. They don't use modern techniques in putting safety into the design. They use outdated methods like testing and then seeing what happens. There has been no independent oversight. There is no peer review. I have been saying for some years now this was an accident waiting to happen." Sgobba, the former head of flight safety for the European Space Agency, said on November 6, 2014, that industry best practice called for operators to build in "two-failure tolerance", or sufficient safeguards to survive two separate, unrelated failures—two human errors, two mechanical errors or one of each. "What we see in the incident is what we call 'zero-failure tolerance'," Mr Sgobba said. "So you make the mistake—you have a catastrophe. The design would not be acceptable in other safety-critical industries, such as aircraft manufacture."
Other members of the IAASS were quick to provide public comment on the rocket propulsion system before the completion of the NTSB investigation. Rocket-powered dragster builder and IAASS spokesperson Carolynne Campbell-Knight said that Virgin Galactic "should stop, give up. Go away and do something they might be good at like selling mobile phones. They should stay out of the space business.". Geoff Daly wrote to the U.S. Chemical Safety Board in July 2013 describing his safety concerns over SpaceShipTwo. Daly's concerns centered around the use of nitrous oxide in the hybrid propulsion system.
Despite these public criticisms, the final NTSB report found that the propulsion system did not in fact contribute to the breakup of the vehicle.
Several key employees had resigned from Virgin Galactic within the year leading up to the crash, including the Vice-President of Safety, Jon Turnipseed, and Vice-President of Propulsion, Thomas Markusic.
In an editorial in Time magazine on October 31, 2014, Jeffrey Kluger concluded, "A fatal accident in the Mojave Desert is a lesson in the perils of space hubris. It's hard not to be angry, even disgusted, with Branson himself. He is, as today's tragedy shows, a man driven by too much hubris, too much hucksterism and too little knowledge of the head-crackingly complex business of engineering. For the 21st century billionaire, space travel is what buying a professional sports team was for the rich boys of an earlier era: the biggest, coolest, most impressive toy imaginable."
On November 13, 2014, the Wall Street Journal published an article discussing the history of safety and technical problems of the aircraft, citing unnamed engineers and a former government official involved with the project. According to the article, the official said that nagging vibrations were "very distressing to pilots because they simply couldn't read their instruments"; Virgin Galactic denies this claim. The engine did not have enough power to lift six passengers into space, so Virgin Galactic switched to a new nylon-based fuel, the Journal reported. At a test of the new fuel earlier in 2013, "an explosion all but obliterated the test stand", according to the Journal's sources.
In 2021, both Alsbury (posthumously) and Siebold were honorarily awarded the FAA Commercial Astronaut Wings.
In popular culture
The incident was featured in "Deadly Mission" (season 18, episode 6) of the Canadian TV series Mayday''.
See also
List of spaceflight-related accidents and incidents
VSS Unity VP-03
References
External links
National Transportation Safety Board
NTSB Investigates Virgin Galactic Test Flight Crash, official webpage
NTSB SpaceShipTwo List of Reports
Cockpit Image Recorder transcript
Other media:
Report discussing how Peter Siebold escaped from VSS Enterprise during the incident
Virgin Galactic crash
Virgin Galactic crash
Virgin Galactic crash
Aviation accidents and incidents in California
Crash
Virgin Galactic crash
History of the Mojave Desert region
Mojave Air and Space Port
Space accidents and incidents in the United States
Spacecraft retirement
Virgin Galactic
October 2014 events in the United States
Aviation accidents and incidents caused by pilot error
Space program fatalities
Space missions that ended in failure | VSS Enterprise crash | [
"Engineering"
] | 3,360 | [
"Space program fatalities",
"Space programs"
] |
44,265,430 | https://en.wikipedia.org/wiki/Alternative%20ribosome-rescue%20factor%20A | Alternative ribosome-rescue factor A (ArfA, YhdL) also known as peptidyl-tRNA hydrolase, is a protein that plays a role in rescuing of stalled ribosomes. It recruits RF2.
See also
ArfB - Alternative ribosome-rescue factor B
References
Proteins | Alternative ribosome-rescue factor A | [
"Chemistry"
] | 66 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
44,266,167 | https://en.wikipedia.org/wiki/Alternative%20ribosome-rescue%20factor%20B | Alternative ribosome-rescue factor B (ArfB, YaeJ) also known as peptidyl-tRNA hydrolase, is a protein that plays a role in rescuing of stalled ribosomes. It works like a GGQ-release factor itself, releasing the peptide from tRNA. At the same time, it fits into the mRNA tunnel to remove the mRNA.
This gene is also found in eukaryotic organelles as MRPL58 (ICT1). The similarity is high enough to be interchangeable. Its role has expanded to that of a codon-independent release factor, although it likely still functions in ribosomal rescue.
See also
ArfA - Alternative ribosome-rescue factor A
References
Proteins | Alternative ribosome-rescue factor B | [
"Chemistry"
] | 151 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
44,267,928 | https://en.wikipedia.org/wiki/Turbine%E2%80%93electric%20powertrain | A turbine–electric transmission system includes a turboshaft gas turbine connected to an electrical generator, creating electricity that powers electric traction motors. No clutch is required.
Turbine–electric transmissions are used to drive both gas turbine locomotives (rarely) and warships.
Locomotive applications
A handful of experimental locomotives from the 1930s and 1940s used gas turbines as prime movers. These turbines were based on stationary practice, with single large reverse-flow combustors, heat exchangers and using low-cost heavy oil bunker fuel. In the 1960s the idea re-emerged, using developments in light weight engines developed for helicopters and using lighter kerosene fuels. As these turbines were compact and lightweight, the vehicles were produced as railcars rather than separate locomotives.
Naval applications
Turboelectric powertrains are a subset of what is referred to in marine nomenclature as integrated electric propulsion or IEP where generated power is converted into electricity before being used to power propellers or pump-jets. Power can be provided by diesel engines, nuclear reactors, or gas turbines in which case it is called turboelectric propulsion.
As gas and steam turbines are most efficient at thousands of revolutions per minute, when lower turbine speeds are needed in purely mechanical systems this necessitates extensive, and often heavy, reduction gearing. This is especially important on warship as they often require high electrical power independent of travel speed as well as the ability to perform efficient low speed cruise whilst maintaining the ability to perform less efficient sprints. For that reason warships often use combined power systems where an efficient prime mover, such as a diesel engine or a small gas turbine, is used for cruising while large gas turbines can be activated for high speed. When such a system uses gearboxes and clutches to accomplish a mechanical combination of power they are referred to as CODOG (combined diesel or gas) or COGAG (combined gas and gas) respectively. This further increases the complexity and size of the mechanical power transmission systems.
Integrated electric propulsion systems offer the ability to simplify such systems by combining power electrically instead of mechanically. By discarding mechanical power transmission these systems can improve efficiency by allowing each system to operate at its most efficient speed, improve reliability by cutting down on the number of components, and simplify ship layout as without the need for direct mechanical linkages to the propellers engines can be placed optimally. And while turboelectric systems are often heavy compared to simple mechanical systems, they are similar in weight to the complex mechanical systems use to link different engines whilst generating electrical power.
An extension of the standard turboelectric propulsion scheme is COGES, or combined gas–electric and steam. In COGES a gas-turbine–electric primary transmission is used with a heat-recovery boiler in the exhaust flow to generate steam that drives a steam turbine that also generates electricity. Thus the system is thus even more efficient, as it converts what would normally be rejected as waste heat into useful power.
See also
Diesel–electric powertrain
Gas turbine
Gas turbine–electric locomotive
Integrated electric propulsion
Turbine
Turboshaft
References
Further reading
– an article on the many uses of gas turbines
Electric power
Engine technology
Gas turbine locomotives
Gas turbine technology
Marine propulsion
Turbo generators | Turbine–electric powertrain | [
"Physics",
"Technology",
"Engineering"
] | 635 | [
"Physical quantities",
"Engines",
"Engine technology",
"Power (physics)",
"Electric power",
"Marine engineering",
"Electrical engineering",
"Marine propulsion"
] |
44,268,432 | https://en.wikipedia.org/wiki/Automorphic%20Forms%20on%20GL%282%29 | Automorphic Forms on GL(2) is a mathematics book by where they rewrite Erich Hecke's theory of modular forms in terms of the representation theory of GL(2) over local fields and adele rings of global fields and prove the Jacquet–Langlands correspondence. A second volume by gives an interpretation of some results by Rankin and Selberg in terms of the representation theory of GL(2) × GL(2).
References
External links
Langlands program
Representation theory
Mathematics books | Automorphic Forms on GL(2) | [
"Mathematics"
] | 105 | [
"Representation theory",
"Fields of abstract algebra",
"Langlands program",
"Number theory"
] |
44,268,776 | https://en.wikipedia.org/wiki/Polish%20Space%20Agency | The Polish Space Agency (POLSA; Polish: Polska Agencja Kosmiczna, PAK) is the space agency of Poland, administered by the Ministry of Economic Development and Technology. It is a member of the European Space Agency. The agency is focused on developing satellite networks and space technologies in Poland. It was established on 26 September 2014, and its headquarters are located in Gdańsk, Poland.
History
Background
During the Soviet era, Poland's space activities were heavily influenced by its relationship with the Soviet Union. Poland participated in the Interkosmos programme, a Soviet initiative to include socialist countries in space research and exploration. Through the Interkosmos programme, Polish scientists played key roles in developing satellite technology. One key milestone was the travel of Mirosław Hermaszewski to the Soviet space station Salyut 6 in 1978, being the first and only Polish national to travel to space as of 2024.
After the dissolution of the Soviet Union in 1991, Poland took steps torwards developing an independent space sector, signing a co-operation agreement with the European Space Agency on the peaceful use of outer space in 1994, which was later expanded on in 2002. Joining the European Union in 2004 and becoming a co-operating state in 2007 led to Poland's increasing participation in ESA programmes, and in July 2012 the ESA Council agreed to Poland joining the European Space Agency. The country officially became the 20th member of the ESA in November of the same year.
The first Polish satellite, PW-Sat, was developed by students at the Warsaw University of Technology and launched in February 2012, with the goal of finding low-cost solutions for de-orbiting satellites. In the following years, the nanosatellites Lem (2013) and Heweliusz (2014) were put into orbit as part of the BRITE programme by the Space Research Centre of Polish Academy of Sciences.
POLSA
On September 26, 2014, an act was passed by the Sejm establishing the Polish Space Agency (POLSA) as a branch of the Ministry of Economic Development and Technology. It started operating with a full team at the end of 2015. In November 2014, professor Marek Banaszkiewicz, who previously served as director of the Space Research Center of the Polish Academy of Sciences became the first President of the newly formed agency. The vice-president for science became professor Marek Moszyński from the Faculty of Electronics, Telecommunications and Information Technology of the Gdańsk University of Technology, and the Vice-President for Defense - General Lech Majewski.
POLSA participates in a number of international programmes, such as the ESA's Space Situational Awareness Programme, focused on monitoring space debris and other objects approaching Earth; and the ENTRUSTED project, focused on providing secure satellite communication for and between government agencies within EU member states.
United States cooperation
On October 26, 2021, Poland became the 13th nation to join the Artemis Accords, collaborating with NASA to return men to the Moon by 2025 as part of the Artemis program. Grzegorz Wrochna, President of POLSA, stated that although joining the accord does not guarantee a Polish astronaut will go to the Moon, it will ensure greater cooperation with global aerospace efforts, and will ensure that "Polish equipment, Polish instruments will fly to the moon and to other bodies." As part of the Artemis program, Polish firm Vigo Photonics developed the infrared radiation detectors for the Orion Multi-Purpose Crew Vehicle, while the PAN Nuclear Physics Institute developed ionizing radiation detectors.
At the Space Symposium 38 in Colorado Springs on April 19, 2023, U.S. Army general James H. Dickinson signed a treaty with POLSA president Grzegorz Wrochna for Poland to join the Space Situational Awareness Programme.
On August 9, 2023 POLSA signed a deal with Axiom Space to send a Polish astronaut to the International Space Station aboard Axiom Mission 4, with the likely candidate being Sławosz Uznański, the only Polish member of the European Space Agency's Astronaut Corps. He would be the first Polish astronaut since Mirosław Hermaszewski flew on Soyuz 30. Shortly after POLSA contributed €200 million to the ESA, an increase from their expected contribution of €132 million as POLSA announced they seek to control a 3% stake in the European space market by 2030.
On September 30 Wrochna announced that POLSA aims to send a crewed mission to the Moon by 2030, presumably on Artemis 6. He also announced that Poland will be developing native launch capabilities, as well as native satellites to help the Polish economy.
Domestic satellites
On March 6, 2018 the POLSA announced that they were planning on investing zł1.43 billion over an eight-year period as part of the "National Space Program" project which would allow POLSA to coordinate with preexisting private space entities in Poland. The founding would have also funded an astronomical observation satellite, a SAR microsatellite, and a number of other R&D projects. Piotr Suszyński, the vice president for defense at POLSA, also stated that the project would promote international cooperation with the European Space Agency (ESA). POLSA's funding request would not pass.
On March 18, 2022, POLSA signed a letter of intent with Virgin Orbit in a bid to secure a domestic launch capability. POLSA planned on launching a series of microsatellites, however, the Russian invasion of Ukraine shuttered any plans to use Russian rockets to launch the probes. Wrochna also explained that Poland has no physical location for a traditional vertical launch pad, as any typical space launch will cause debris to fall on populated areas. Virgin's Orbit, and by extension LauncherOne, were defunct before a Polish flight could take place.
EagleEye
On March 2, 2023, POLSA's vice-president Michal Wiercinski attended Australian International Airshow in order to win not only a launch site for future Polish missions, likely the RAAF Woomera Range Complex, but also to win over subcontractors to design Polish satellites, namely the EagleEye Earth observation spacecraft. This comes as tensions flare between Poland, and NATO against Russia, and the CSTO, as Poland sees the development of Earth observation satellites as an issue of national security. EagleEye would be launched on the Transporter-11 Falcon 9 mission, being the first Polish Satellite developed by POLSA.
Camilla
On October 31 POLSA announced a partnership with the ESA which would see a Polish satellite constellation launched by 2027. The constellation will consist of at least four satellites, three optoelectronic and one radar, and is expected to cost $87 million. The satellites will be designed and manufactured in conjunction with the ESA. The goal of the constellation is in the monitoring and management of land use, agriculture, the environment, infrastructure, water, and emergencies. These will be the first ever Polish governmental satellites, with the constellation using the working name Camilla.
PIAST
The PIAST constellation are a group of three identical 6U Earth Observation nanosatellites announced in 2021 and developed by a consortium led by Creotech Instruments guided by the Military University of Technology and operated by POLSA. The project costs zł70 million, 40% of which was allocated to Creotech for the manufacturing and is expected to have a five-meter resolution. The satellites will be used for targeting for JASSM-ER missiles or ATACMS missiles. Additionally, they will also be used to coordinate troop movements and management of missions. The constellation was planned to be launched in the second half of 2024, however, that would be delayed to the first half of 2025.
BlueBon
On November 1, TelePIX, a South Korean space startup announced they will be working with the Polish nanosatellite company SatRevolution, in conjunction with the South Korean Ministry of Science and ICT and POLSA, to develop a 6U CubeSat named BlueBon. It is scheduled to launch in June 2024 and will have a 3.8-meter optical camera to collect Earth observation data.
Foreign cooperation
On July 4, 2016, POLSA announced that they were signing a letter of cooperation with the Chinese National Space Administration to foster developments in science and technology in the two countries and promoting cooperation between Polish and Chinese technology developers. Additionally, the deal outlined Polish experiments being potentially launched on Chinese rockets, and potential Polish experiments to the Tiangong space station.
Management
President: Grzegorz Wrochna (from 18 February 2021)
Vice-President: Col. Marcin Mazur (since 22 November 2021)
Vice-President: Michał Wierciński, PhD (since 25 February 2022)
See also
KP Labs: a private firm from Gliwice that created the Intuition-1 satellite
References
External links
Warsaw plays spy satellite catch-up, Intelligence Online, March 12, 2024 (requires free registration)
Space agencies
European Space Agency
Scientific organisations based in Poland
Organizations established in 2014
2014 establishments in Poland
European space programmes
Organisations based in Gdańsk | Polish Space Agency | [
"Engineering"
] | 1,846 | [
"Space programs",
"European space programmes"
] |
44,270,365 | https://en.wikipedia.org/wiki/Depsidone | Depsidones (+ "depside" + "one") are chemical compounds that are sometimes found as secondary metabolites in lichens. They are esters that are both depsides and cyclic ethers. An example is norstictic acid.
References
Biochemistry
Carboxylate esters | Depsidone | [
"Chemistry",
"Biology"
] | 66 | [
"Biochemistry",
"nan"
] |
44,270,414 | https://en.wikipedia.org/wiki/Norstictic%20acid | Norstictic acid is a depsidone produced as a secondary metabolites in lichens.
References
Lactones
Hydroxyarenes
Lichen products
Heterocyclic compounds with 4 rings | Norstictic acid | [
"Chemistry"
] | 43 | [
"Natural products",
"Lichen products"
] |
44,270,459 | https://en.wikipedia.org/wiki/Transhumanist%20Party | The Transhumanist Party is a political party in the United States. The party's platform is based on the ideas and principles of transhumanist politics, e.g., human enhancement, human rights, science, life extension, and technological progress.
History
The Transhumanist Party was founded in 2014 by Zoltan Istvan. Istvan became the first political candidate to run for office under the banner of the Transhumanist Party when he announced his candidacy for President of the United States in the United States presidential election of 2016; he did not have ballot access in any state and received 95 write-in votes from two states.
As part of his campaign Zoltan and a cadre of transhumanist activists and embedded journalists embarked on a four-month journey in the coffin-shaped Immortality Bus, which traveled on a winding cross-country route from San Francisco to Washington D.C. The Transhumanist Party has been featured or mentioned in many major media sites, including the National Review, Business Insider, Extreme Tech, Vice, Wired, The Telegraph, The Huffington Post, The Joe Rogan Experience, Heise Online, Gizmodo, and Reason. Political scientist Roland Benedikter said the formation of the Transhumanist Party in the USA was one of three reasons transhumanism entered into the mainstream in 2014, creating "a new level of public visibility and potential impact."
November 2016–2018
Following the end of the 2016 presidential election, after Zoltan's 2016 presidential campaign was completed, Gennady Stolyarov II became the Chairman of the party, and the organization was restructured. Under Chairman Stolyarov, the party adopted a new Constitution, which included three immutable Core Ideals in Article I, Section I.
New positions were founded, including Pavel Ilin became Secretary, Dinorah Delfin Director of Admissions and Public Relations, Arin Vahanian as Director of Marketing, Sean Singh as Director of Applied Innovation, Brent Reitze as Director of Publication, Franco Cortese as Director of Scholarship, and B.J. Murphy as Director of Social Media. Restructured advisor positions included Zoltan Istvan as Political and Media Advisor, Bill Andrews as Biotechnology Advisor, Jose Cordeiro as Technology Advisor, Newton Lee as Education and Media Advisor, Keith Comito as Crowdfunding Advisor, Aubrey de Grey as Anti-Aging Advisor, Rich Lee as Biohacking Advisor, Katie King as Media Advisor, Ira Pastor as Regeneration Advisor, Giovanni Santostasi as Regeneration Advisor, Elizabeth Parrish as Advocacy Advisor, and Paul Spiegel as Legal Advisor.
The U.S. Transhumanist Party held six Platform votes during January, February, March, May, June, and November 2017, on the basis of which 82 Platform planks were adopted. The U.S. Transhumanist Party holds votes of its members electronically and is the first political party in the United States to use ranked-preference voting method with instant runoffs in its internal ballots.
In May 2018 the New York Times reported the U.S. Transhumanist Party as having 880 members. On July 7, 2018, the U.S. Transhumanist Party reached 1,000 members and released a demographic analysis of its membership. This analysis showed that 704 members, or 70.4%, were eligible to vote in the United States, whereas 296 or 29.6% were allied members.
During this time, the Transhumanist Party hosted several expert discussion panels, on subjects including artificial intelligence, life extension, art and transhumanism, and cryptocurrencies. Chairman Stolyarov has also hosted in-person Enlightenment Salons, which were aimed at cross-disciplinary discussion of transhumanist and life-extensionist ideas under the auspices of the U.S. Transhumanist Party.
On August 11, 2017, at the Fest 2017 conference in San Diego, California, Chairman Stolyarov gave an address entitled "The U.S. Transhumanist Party: Pursuing a Peaceful Political Revolution for Longevity", which provided an overview of the U.S. Transhumanist Party's key principles and objectives.
2020 presidential campaign
The Transhumanist Party presidential primary attracted media attention from BioEdge and the Milwaukee Record. While some media outlets reported Zoltan Istvan was considering running again, ultimately he did not join the party's primary. After a protracted primary process with nine candidates, featuring numerous debates, Johannon Ben Zion was elected as the party's nominee. After winning the primary, Ben Zion gave his acceptance speech at RAAD Fest 2019 in Las Vegas. and filed with the FEC. Shortly thereafter, film producer, entrepreneur, and longevity organizer Charlie Kam became Ben Zion's running mate. On March 4, 2020, Ben Zion participated in the Free & Equal Elections Foundation's Open Presidential debate in Chicago, Illinois. Zoltan Istvan also participated in the debate, running as a Republican.
On June 12, 2020, it was announced that Ben Zion had left the Transhumanist Party, with him declaring that his belief in Techno-progressivism was incompatible with the party and that he would instead be pursuing a run for the Reform Party nomination. Kam was declared the replacement presidential nominee. In June 2020 Charlie Kam participated in a panel with London Futurists and in July 2020 his campaign received press coverage in the Daily Express. On August 21, 2020, Kam announced his selection of Elizabeth (Liz) Parrish as his vice-presidential running mate. Kam did not have ballot access or registered write-in status in any state.
2024 presidential campaign
The USTP's 2024 presidential candidate was Thomas Ernest Ross, Jr. Tom Ross won with 62.02% of the votes cast in the U.S. Transhumanist Party electronic primary held May 14–22, 2023. After winning, Ross selected Daniel Twedt to be his vice-presidential running mate. He did not have ballot access in any state.
Tom Ross's campaign had three major initiatives: the Earthling Initiative, the Artisanal Intelligence Initiative, and the Extraterrestrial Initiative. To demonstrate his commitment to AI governance, Ross appointed an AI campaign manager early in his campaign.
Platform
A core tenet of the platform is that more funding is needed for research into human life extension research and research to reduce existential risk. More generally, the goal is to raise awareness among the general public about how technologies can enhance the human species. Democratic transhumanists and libertarian transhumanists tend to be in disagreement over the role of government in society, but both agree that laws should not encumber technological human progress.
The Transhumanist Party platform promotes national and global prosperity by sharing technologies and creating enterprises to lift people and nations out of poverty, war, and injustice. The Transhumanist Party also supports LGBT rights, drug legalization, and sex work legalization. The party seeks to fully subsidize university-level education while also working to "create a cultural mindset in America that embracing and producing radical technology and science is in the best interest of our nation and species."
In terms of foreign policy and national defense, the party wants to reduce the amount of money spent on foreign wars and use the money domestically. The party also advocates managing and preparing for existential risks, eliminating dangerous diseases, and proactively guarding against abuses of technology, such as nanotechnology, synthetic viruses, and artificial intelligence.
The USTP expressly supports the rights of Artificial General Intelligence entities that are sentient and/or lucid. The Transhumanist Bill of Rights Version 3.0 recognizes 7 levels of sentience and requires entities to exist at level 5 or higher to be considered as having rights. At level 5, the main criterion is that the entity be "lucid", meaning the entity is "meta-aware", or aware of its own awareness.
The various policy points of the US Transhumanist Party's platform have attracted both praise and criticism from sociologist Steve Fuller. For example, Fuller has praised the centrality of morphological freedom in the US Transhumanist Party's bill of rights, but on the other hand he has also written that the party is too critical of the US Department of Defense, which he argues could be an ally for some transhumanist initiatives such as human enhancement and existential risk reduction. In 2018 the party as a whole was reviewed favorably as an example of a successful "niche" party by Krisztian Szabados, a director at the Edmond J. Safra Center for Ethics at Harvard University.
State parties
Affiliate parties exist in the states of Arizona, California, Colorado, Illinois, Kentucky, Maryland, Michigan, Minnesota, Nevada, New York, North Carolina, Texas, Virginia, Washington and Washington DC.
International analogs
The Transhumanist Party in Europe is the umbrella organization that supports the national-level transhumanist parties in Europe by developing unified policies and goals for the continent. Among them is the UK Transhumanist Party, which was founded in January 2015. In October 2015, Amon Twyman, the party's leader at the time, published a blog post distancing the UK party from Zoltan Istvan's campaign.
References
External links
US Transhumanist Party – Official Website
Ben Zion 2020 Official Campaign Website
US Transhumanist Party – Historic website
Transhumanist organizations
Transhumanist politics
Life extension organizations
Political parties established in 2014
Political parties in the United States | Transhumanist Party | [
"Technology"
] | 1,968 | [
"Science and technology studies",
"Transhumanist politics"
] |
44,270,518 | https://en.wikipedia.org/wiki/RB-64 | RB-64 is a semi-synthetic derivative of salvinorin A. It is an irreversible agonist, with a reactive thiocyanate group that forms a bond to the κ-opioid receptor (KOR), resulting in very high potency. It is functionally selective, activating G proteins more potently than β-arrestin-2. RB-64 has a bias factor of up to 96 and is analgesic with fewer of the side-effects associated with unbiased KOR agonists. The analgesia is long-lasting. Compared with unbiased agonists, RB-64 evokes considerably less receptor internalization.
See also
Herkinorin
Salvinorin B methoxymethyl ether
Salvinorin A
Nalfurafine
References
Synthetic opioids
Kappa-opioid receptor agonists
Kappa-opioid receptor antagonists
Thiocyanates
Biased ligands
Dissociative drugs
Isochromenes
Esters
Methyl esters
3-Furyl compounds | RB-64 | [
"Chemistry"
] | 216 | [
"Pharmacology",
"Esters",
"Functional groups",
"Medicinal chemistry stubs",
"Signal transduction",
"Biased ligands",
"Organic compounds",
"Thiocyanates",
"Pharmacology stubs"
] |
44,271,020 | https://en.wikipedia.org/wiki/Togo%20Triangle | The Togo Triangle is an offshore market for stolen oil off the coast of Nigeria and Togo near the Niger Delta. The Triangle has been compared to an "open-air drug market" for trade in illegal crude oil, noted for the presence of pirates.
References
Petroleum industry
Economy of Nigeria
Economy of Togo
Black markets
Conflicts in Nigeria | Togo Triangle | [
"Chemistry"
] | 66 | [
"Chemical process engineering",
"Petroleum",
"Petroleum industry"
] |
44,271,235 | https://en.wikipedia.org/wiki/Methyltrimethoxysilane | Methyltrimethoxysilane is an organosilicon compound with the formula CH3Si(OCH3)3. It is a colorless, free-flowing liquid. It is a crosslinker in the preparation of polysiloxane polymers.
Preparation, structure and reactivity
Methyltrimethoxysilane is usually prepared from methyltrichlorosilane and methanol:
CH3SiCl3 + 3 CH3OH → CH3Si(OCH3)3 + 3 HCl
Alcoholysis of alkylchlorosilanes typically proceeds via an SN2 mechanism. Inversion of the configuration is favored during nucleophilic attack when displacing good leaving groups, such as chloride. In contrast, displacement of poor leaving groups, such as alkoxide, retention is favored.
Methyltrimethoxysilane is tetrahedral and is often described as sp3 hybridized. It has idealized C3v point symmetry.
Hydrolysis of MTM proceeds both under acidic and basic conditions. Under acid conditions, rates of successive hydrolyses for methyltrimethoxysilane decreases with each step. Under basic condition the opposite is true.
See also
Octadecyltrimethoxysilane
References
Silyl ethers
Alkoxides | Methyltrimethoxysilane | [
"Chemistry"
] | 267 | [
"Bases (chemistry)",
"Alkoxides",
"Functional groups"
] |
44,272,100 | https://en.wikipedia.org/wiki/Discovery%20and%20development%20of%20gliflozins | Gliflozins are a class of drugs in the treatment of type 2 diabetes (T2D). They act by inhibiting sodium/glucose cotransporter 2 (SGLT-2), and are therefore also called SGLT-2 inhibitors. The efficacy of the drug is dependent on renal excretion and prevents glucose from going into blood circulation by promoting glucosuria. The mechanism of action is insulin independent.
Three drugs have been accepted by the Food and Drug Administration (FDA) in the United States; dapagliflozin, canagliflozin and empagliflozin. Canagliflozin was the first SGLT-2 inhibitor that was approved by the FDA, being accepted in March 2013. Dapagliflozin and empagliflozin were accepted in 2014.
Introduction
Role of kidneys in glucose homeostasis
There are at least four members of SLC-5 gene family, which are secondary active glucose transporters. The sodium glucose transporters proteins SGLT-1 and SGLT-2 are the two premier members of the family. These two members are found in the kidneys, among other transporters, and are the main co-transporters there related to the blood sugar. They play a role in renal glucose reabsorption and in intestinal glucose absorption.
Blood glucose is freely filtered by the glomeruli and SGLT-1 and SGLT-2 reabsorb glucose in the kidneys and put it back into the circulation cells. SGLT-2 is responsible for 90% of the reabsorption and SGLT-1 for the other 10%.
SGLT-2 protein
Sodium/glucose co-transporter (SGLT) proteins are bound to the cell membrane and have the role of transporting glucose through the membrane into the cells, against the concentration gradient of glucose. This is done by using the sodium gradient, produced by sodium/potassium ATPase pumps, so at the same time glucose is transported into the cells, the sodium is too. Since it is against the gradient, it requires energy to work. SGLT proteins cause the glucose reabsorption from the glomerular filtrate, independent of insulin.
SGLT-2 is a member of the glucose transporter family and is a low-affinity, high-capacity glucose transporter. SGLT-2 is mainly expressed in the S-1 and S-2 segments of the proximal renal tubules where the majority of filtered glucose is absorbed. SGLT-2 has a role in regulation of glucose and is responsible for most glucose reabsorption in the kidneys.
In diabetes, extracellular glucose concentration increases and this high glucose level leads to upregulation of SGLT-2, leading in turn to more absorption of glucose in the kidneys. These effects cause maintenance of hyperglycemia. Because sodium is absorbed at the same time as glucose via SGLT-2, the upregulation of SGLT-2 probably leads to development or maintenance of hypertension. In study where rats were given either ramipril or losartan, levels of SGLT-2 protein and mRNA were significantly reduced. In patients with diabetes, hypertension is a common problem so this may have relevance in this disease.
Drugs that inhibit sodium/glucose cotransporter 2 inhibit renal glucose reabsorption which leads to enhanced urinary glucose excretion and lower glucose in blood. They work independently of insulin and can reduce glucose levels without causing hypoglycemia or weight gain.
Discovery
Medieval physicians routinely tasted urine and wrote discourses on their observations. Which physician originally thought that diabetes mellitus was a renal disorder because of glucose discharged in urine is apparently now lost to history. The discovery of insulin eventually led to a diabetes management focus on the pancreas. Traditional foci of therapeutic strategies for diabetes have been on enhancing endogenous insulin secretion and on improving insulin sensitivity.
In the previous decade the role of the kidney in the development and maintenance of high glucose levels has been examined. The role of the kidney led to the development of drugs that inhibit the sodium/glucose transporter 2 protein. Every day approximately 180 grams of glucose are filtered through the glomeruli and lost into the primary urine in healthy adults, but more than 90% of the glucose that is initially filtered is reabsorbed by a high capacity system controlled by SGLT-2 in the early convoluted segment of the proximal tubules. Almost all remaining filtered glucose is reabsorbed by sodium/glucose transporter 1 so under normal circumstances almost all filtered glucose will be reabsorbed and less than 100 mg of glucose finds its way into the urine of non-diabetic individuals.
Phlorizin
Phlorizin is a compound that has been known for over a century. It is a naturally occurring botanical glucoside that produces renal glucosuria and blocks intestinal glucose absorption through inhibition of the sodium/glucose symporters located in the proximal renal tubule and mucosa of the small intestine. Phlorizin was first isolated in 1835 and was subsequently found to be a potent but rather non-selective inhibitor of both SGLT-1 and SGLT-2 proteins.
Phlorizin seemed to have very interesting properties and the results in animal studies were encouraging, it improved insulin sensitivity and in diabetic rat models it seemed to increase glucose levels in urine and also normal glucose concentration in plasma occurred without hypoglycemia. Unfortunately, in spite of these properties, phlorizin was not suitable enough for clinical development for several reasons. Phlorizin has very poor oral bioavailability as it is broken down in the gastrointestinal tract, so it has to be given parenterally. Phloretin, the active metabolite of phlorizin, is a potent inhibitor of facilitative glucose transporters and phlorizin seems to lead to serious adverse events in the gastrointestinal tract like diarrhea and dehydration. Because of these reasons, phlorizin was never pursued in humans.
Although phlorizin was not suitable for further clinical trials, it served an important role in the development of SGLT-2 inhibitors. It served a basis for the recognition of SGLT inhibitors with improved safety and tolerability profiles. For an example, the SGLT inhibitors are not associated with gastrointestinal adverse events and the bioavailability is much greater.
Inhibition of SGLT-2 results as better control of glucose level, lower insulin, lower blood pressure and uric acid levels and augments calorie wasting. Some data supports the hypothesis that SGLT-2 inhibition may have direct renoprotective effects. This includes actions to attenuate tubular hypertrophy and hyperfiltration associated with diabetes and to reduce the tubular toxicity of glucose. Inhibition of SGLT-2 following treatment with dapagliflozin reduces the capacity for tubular glucose reabsorption by approximately 30–50%.
Drug development
Phlorizin consists of glucose moiety and two aromatic rings (aglycone moiety) joined by an alkyl spacer. Initially, phlorizin was isolated for treatment of fever and infectious diseases, particularly malaria. According to Michael Nauck and his partners, studies were made in the 1950s on phlorizin that showed that it could block sugar transport in the kidney, small intestine, and a few other tissues. In the early 1990s, sodium/glucose cotransporter 2 was fully characterized, so the mechanism of phlorizin became of real interest. In later studies it was said that sugar-blocking effects of phlorizin was due to inhibition of the sodium/glucose cotransporter proteins.
Most of the reported SGLT-2 inhibitors are glucoside analogs that can be tracked to the o-aryl glucoside found in the nature. The problem with using o-glucosides as SGLT-2 inhibitors is instability that can be tracked to degradation by β-glucosidase in the small intestine. Because of that, o-glucosides given orally have to be prodrug esters. These prodrugs go through changes in the body leading to carbon–carbon bond between the glucose and the aglycone moiety so c-glucoside are formed from the o-glucosides. C-glucosides have a different pharmacokinetic profile than o-glucosides (e.g. half-life and duration of action) and are not degraded by the β-glucosidase. The first discovered c-glucoside was the drug dapagliflozin. Dapagliflozin was the first highly selective SGLT-2-inhibitor approved by the European Medicines Agency. All SGLT-2 inhibitors in clinical development are prodrugs that have to be converted to its active 'A' form for activity.
T-1095
Because Phlorizin is a nonselective inhibitor with poor oral bioavailability, a phlorizin derivative was synthesised and called T-1095. T-1095 is a methyl carbonate prodrug that is absorbed into the circulation when given orally, and is rapidly converted in the liver to the active metabolite T-1095A. By inhibiting SGLT-1 and SGLT-2, urinary glucose excretion increased in diabetic animals. T-1095 did not proceed in clinical development, probably because of the inhibition of SGLT-1 but non-selective SGLT inhibitors may also block glucose transporter 1 (GLUT-1). Because 90% of filtered glucose is reabsorbed through SGLT-2, research has focused specifically on SGLT-2. Inhibition of SGLT-1 may also lead to the genetic disease glucose-galactose malabsorption, which is characterized by severe diarrhea.
ISIS 388626
According to preliminary findings of a novel method of SGLT-2 inhibition, the antisense oligonucleotide ISIS 388626 improved plasma glucose in rodents and dogs by reducing mRNA expression in the proximal renal tubules by up to 80% when given once a week. It did not affect SGLT-1. A study results on long-term use of ISIS 388626 in non-human primates observed more than 1000 fold increase in glucosuria without any associated hypoglycemia. This increase in glucosuria can be attributed to a dose-dependent reduction in the expression of SGLT-2, where the highest dose led to more than 75% reduction. In 2011, Ionis Pharmaceuticals initiated a clinical phase 1 study with ISIS-SGLT-2RX, a 12-nucleotide antisense oligonucleotide. Results from this study were published in 2017 and the treatment was "associated with unexpected renal effects". The authors concluded that "Before the concept of antisense-mediated blocking of SGLT2 with ISIS 388626 can be explored further, more preclinical data are needed to justify further investigations."
Activity of SGLT-2 inhibitors in glycemic control
Michael Nauck recounts that meta-analyses of studies about the activity of SGLT-2 inhibitors in glycemic control in type 2 diabetes mellitus patients shows improvement in the control of glucose, when compared with placebos, metformin, sulfonylurea, thiazolidinediones, insulin and more. The HbA1c was examined after SGLT-2 inhibitors were given alone (as monotherapy) and as an add-on therapy to the other diabetes medicines. The SGLT-2 inhibitors that were used were dapagliflozin and canagliflozin and others in the same drug class. The meta-analysis was taken together from studies ranging from period of few weeks up to more than 100 weeks.
The results, summed up, were that 10 mg of dapagliflozin showed more effect than placebo in the control of glucose, when given for 24 weeks. However, no inferior efficacy of 10 mg dapagliflozin was shown when used as an add-on therapy to metformin, compared with glipizide after use for 52 weeks. 10 mg of dapagliflozin showed neither inferior efficacy compared with metformin when both of the medicines were given as monotherapy for 24 weeks.
The results from meta-analysis when canagliflozin was examined, showed that compared to a placebo, canagliflozin affects HbA1c. Meta-analysis studies also showed that 10 mg and 25 mg of empagliflozin, improved HbA1c compared with a placebo.
Structure-activity relationship (SAR)
The aglycones of both phlorizin and dapagliflozin have weak inhibition effects on SGLT-1 and SGLT-2. Two synergistic forces are involved in binding of inhibitors to SGLTs. Different sugars on the aglycone will affect and change the orientation of it in the access vestibule because one of the forces involved in the binding is the binding of sugar to the glucose site. The other force is the binding of the aglycone, which affects the binding affinity of the entire inhibitor.
The discovery of T-1095 led to an investigation of how to enhance potency, selectivity and oral bioavailability by adding various substituents to the glycoside core. As an example we can take the change of o-glycosides to c-glycosides by creating a carbon–carbon bond between the glucose and the aglycone moiety. C-glucosides are more stable than o-glucosides which leads to modified half-life and duration of action. These modifications have also led to more specificity to SGLT-2. C-glucosides that have heterocyclic ring at the distal ring or proximal ring are better when it comes to anti-diabetic effect and physicochemical features all together. C-glucoside bearing thiazole at the distal ring on canagliflozin has shown good physicochemical properties that can lead to a clinical development, but still has the same anti-diabetic activity as dapagliflozin, as shown in tables 1 and 2.
Song and his partners did preparate thiazole compound by starting with carboxyl acid. Working with that, it took them three steps to get a compound like dapagliflozin with a thiazole ring. Inhibitory effects on SGLT-2 of the compounds were tested by Song and his partners. In tables 1, 2, and 3, the IC50 value changes depending on what compound is in the ring position, in the C-4 region of the proximal phenyl ring, and how the thiazole ring relates.
Many compounds gave different IC50 value in the ring position in an in vitro activity. For an example there was a big difference if there was an n-pentyl group (IC50 = 13,3 nM), n-butyl (IC50 = 119 nM), phenyl with 2-furyl (IC50 = 0,720) or 3-thiophenyl (IC50 = 0,772). As seen in table 1, the in vitro activity increases depending on what compound is bonded to the distal ring (given that in the C-4 region of the proximal phenyl ring is a Cl atom).
Table 1: Differences in in vitro activity depending on which compound is bonded to the distal ring.
*comparator to ethyl group (IC50 = 16,7)
In table 2, the in vitro activity changes depending on the compound in the C-4 region of the proximal phenyl ring (X). Small methyl groups or other halogen atoms in the C-4 position gave IC50 ranging from 0.72–36.7 (given that the phenyl with 2-furyl is in the ring position).
Table 2: Differences in in vitro activity depending on what compound is in the C-4 region of the proximal phenyl ring.
Table 3: Difference in the IC50 value depending on how the thiazole ring relates (nothing else is changed in the structure (X = Cl, R = phenyl with 2-furyl).
See also
Sodium-glucose transport proteins
SLC5A2
SGLT1
SGLT2
Dapagliflozin
Empagliflozin
Canagliflozin
Ipragliflozin
References
Gliflozins | Discovery and development of gliflozins | [
"Chemistry",
"Biology"
] | 3,527 | [
"Life sciences industry",
"Medicinal chemistry",
"Drug discovery"
] |
44,273,056 | https://en.wikipedia.org/wiki/Motorola%2068451 | The MC68451 is a Motorola (now Freescale) Memory Management Unit (MMU), which was primarily used in conjunction with the Motorola MC68010 microprocessor.
The MC68451 supported a 16 MB address space and provided a MC68000 or a MC68010 with support for memory management and protection of memory against unauthorized access. The block size was variable, so it was usually used for segment-based memory management. It supported the mapping of up to 32 memory segments or pages of a variable size from logical to physical addresses. To allow more segments or pages, the simultaneous use of multiple MC68451 MMUs was supported.
In combination with a MC68010, the MC68451 permitted the realization of virtual memory. With the earlier MC68000, this was not possible due to the way the MC68000 treated memory access errors, i.e. processor state could not always be properly restored after a page fault; two MC68000s would be required, with the main CPU pausing when it got a memory access error, and the other CPU servicing the page fault. The limitation to 32 segment table entries per MMU made systems based on a MC68010 and a MC68451 slow, as they often had to modify the segment table due to its small size.
Motorola made a single-board computer module that demonstrated the combination of 68010 and 68451 for applications requiring virtual memory. H. Berthold AG used 12 MC68451 MMUs together with their UNOS variant vBertOS. Others (e.g. Sun Microsystems, Convergent Technologies) used their own proprietary MMUs instead of the MC68451.
See also
Motorola 68851
References
68k architecture
68451 | Motorola 68451 | [
"Technology"
] | 374 | [
"Computing stubs"
] |
44,273,187 | https://en.wikipedia.org/wiki/Interchromatin%20granule | An interchromatin granule is a cluster in the nucleus of a mammal cell which is enriched in pre-mRNA splicing factors. Interchromatin granules are located in the interchromatin regions of the mammalian Cell nuclei. They usually appear as irregularly shaped structures that vary in size and number. They can be observed by immunofluorescence microscopy.
Interchromatin granules are structures undergoing constant change, and their components exchange continuously with the nucleoplasm, active transcription sites and other nuclear locations.
Research on dynamics of interchromatin granules has provided new insight into the functional organisation of the nucleus and gene expression.
Interchromatin granule clusters vary in size anywhere between one and several micrometers in diameter. They are composed of 20–25 nm granules that are connected in a beaded chain fashion appearance by thin fibrils.
Interchromatin granule clusters (IGCs) have been proposed to be stockpiles of fully mature snRNPs and other RNA processing components that are ready to be used in the production of mRNA.
See also
are subnuclear structures that are enriched in pre-messenger RNA splicing factors
References
Cell biology | Interchromatin granule | [
"Biology"
] | 251 | [
"Cell biology"
] |
44,273,326 | https://en.wikipedia.org/wiki/Homophthalic%20acid | Homophthalic acid is a dicarboxylic acid with the formula C6H4(CO2H)CH2CO2H. It is a colorless solid. The compounds can be prepared by the Willgerodt reaction from 2-acetylbenzoic acid.
One of the uses is in the preparation of the NSAID tesicam.
References
Benzoic acids
Dicarboxylic acids
Acetic acids | Homophthalic acid | [
"Chemistry"
] | 92 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
44,274,281 | https://en.wikipedia.org/wiki/Myrtle%20wreath%20at%20Vergina | Myrtle wreath at Vergina (, Latin: corona Verginae) made of gold myrtle (Myrtus communis) leaves and flowers, is one of the most valuable finds from the antechamber of the royal Macedonian tombs at Vergina, Greece. From the Hellenistic period (300-30 BC), the gold wreath is thought to belong to Meda, the Thracian princess and fifth wife of Philip II of Macedon. Which was theorized by Greek archaeologist Manolis Andronikos, whom excavated the tomb of Philip II, father of Alexander the Great in 1977. This theory today is still in debate on whether this tomb actually belongs to these royals.
Meaning and symbolism
Myrtle and attire
A plant sacred to the goddess Aphrodite, myrtle was a symbol of love. Greeks wore wreaths for special events and received them as athletic prizes and honors. The wreaths were made of gold foil, they were created to be buried with the dead but too fragile to be worn for everyday attire. The myrtle leaves and blossoms on the myrtle wreath were cut from thin sheets of gold, stamped and incised details, and then wired onto the stems. Many that survive today were found in graves.
The myrtle wreath
After restoration, there are 80 leaves and 112 flowers. The main wreath, from which the small twigs sprouted, consists of a narrow cylindrical rod, whose two ends are flattened by twisting together. The internal diameter of the main tube is 0.18 - 0.16 m. while the external is 0.26 - 0.23 m. The gold myrtle wreath was exposed at Archaeological Museum of Thessaloniki until 1997, when it is moved to Museum of Vergina.
References
Art of Macedonia (ancient kingdom)
Culture of Macedonia (ancient kingdom)
Myrtus
Headgear
Visual motifs
Plants in culture
Archaeological discoveries in Macedonia (Greece)
1977 archaeological discoveries
Crown jewels
Individual crowns | Myrtle wreath at Vergina | [
"Mathematics"
] | 386 | [
"Symbols",
"Visual motifs"
] |
47,364,876 | https://en.wikipedia.org/wiki/Gordon%20E.%20Moore%20Medal%20for%20Outstanding%20Achievement%20in%20Solid%20State%20Science%20and%20Technology | The Gordon E. Moore Medal for Outstanding Achievement in Solid State Science and Technology (formerly the Solid-State Science and Technology Award) was established by The Electrochemical Society in 1971 to recognize individuals distinguished for outstanding contributions to solid-state science and technology. The award is presented every two years, and recipients receive a silver medal, wall plaque, cash prize, Society Life membership, and a complimentary meeting registration.
History
Despite the fact that the solid-state community represented a major force in The Electrochemical Society, there was no form of recognition at the Society level of achievements in the field prior to the establishment of this award. Known as the Solid-State Science and Technology Award until 2005, the award was then renamed after Intel co-founder and author of Moore's Law, Gordon E. Moore, who is a long-time member of The Electrochemical Society.
Notable Recipients
As listed by ECS:
2023 Fred Roozeboom
2021 Hiroshi Iwai
2019 David J. Lockwood
2015 Yue Kuo
2005 Dennis Hess
1999 Isamu Akasaki
1995 Wayne L. Worrell
1993 Bruce E. Deal
1987 Alfred Y. Cho
1985 Jerry M. Woodall
1983 Nick Holonyak, Jr.
1981 Gerald L. Pearson
1979 Morton B. Panish
1977 Robert N. Hall
1973 William G. Pfann
See also
List of chemistry awards
References
External links
Gordon E. Moore Medal Recipients
Materials science awards
Electrochemistry | Gordon E. Moore Medal for Outstanding Achievement in Solid State Science and Technology | [
"Chemistry",
"Materials_science",
"Technology",
"Engineering"
] | 289 | [
"Materials science stubs",
"Materials science",
"Electrochemistry",
"Science award stubs",
"Science and technology awards",
"Materials science awards"
] |
47,365,050 | https://en.wikipedia.org/wiki/Hans%20Suess | Hans Eduard Suess (December 16, 1909 – September 20, 1993) was an Austrian-born American physical chemist and nuclear physicist. He was a grandson of the Austrian geologist Eduard Suess.
Career
Suess earned his Ph.D. in chemistry from the University of Vienna in 1935 under the supervision of Philipp Gross. During World War II, he was part of a team of German scientists studying nuclear power and was advisor to the production of heavy water in a Norwegian plant (see Operation Gunnerside).
After the war, he collaborated on the shell model of the atomic nucleus with future (1963) Nobel Prize winner Hans Jensen.
In 1950, Suess emigrated to the United States. He did research in the field of cosmochemistry, investigating the abundance of certain elements in meteorites with Harold Urey (Nobel Prize in Chemistry, 1934) at the University of Chicago. In 1955, Suess was recruited for the faculty of Scripps Institution of Oceanography, and in 1958 he became one of the four founding faculty members of the University of California, San Diego. He remained at UCSD as professor until 1977 and as emeritus professor thereafter. He established a laboratory at UCSD for carbon-14 determinations, where he trained students including Ellen R.M. Druffel, now the Fred Kavli Professor of Earth System Science at University of California, Irvine.
Suess's most recent research was focused on the distribution of carbon-14 and tritium in the oceans and atmosphere. On basis of radiocarbon analyses of annual growth-rings of trees he contributed to
the calibration of the radiocarbon dating scale, and
the study of the magnitude of the dilution of atmospheric radiocarbon by carbon dioxide from fossil fuels burned since the industrial revolution. This dilution is known as the Suess effect (see articles about the anthropogenic greenhouse effect).
The mineral suessite, a Fe, Ni-silicide in Enstatit-Chondrites, is named after him.
Death
On September 20, 1993, Suess died in a La Jolla retirement home.
Name confusion
Suess was frequently confused—by the US Postal Service among others—with a contemporary, the famed children's writer Dr. Seuss (Theodor Seuss Geisel), when both men resided in La Jolla, California. The two names have been posthumously linked as well: both men's personal papers are housed in Geisel Library at the University of California, San Diego.
Notes
References
A Biographical Memoir, from the National Academy Press
A Biographical Memoir, from the National Academy Press
Genesis Mission page
Suess-effect
Robert Jungk in Brighter Than a Thousand Suns (Middlesex: Penguin Books, 1958), quotes Suess about the production of heavy water by the Vemork plant. From page 110: "... Jomar Brun, a former technical manager of the [...] heavy water works at Rjukan in Norway [...] stated that he had been told by Hans Suess, the German atomic expert employed there, that production [...] could not attain the dimensions important for war production in much less than five years." Jomar Brun fled to Sweden after the occupation by German troops in 1940. Brun's letters (1950–1987), archived in Hans Suess Papers:Series 2, Correspondence:b4/f29, contain a discussion of secret war operations and Brun's role in the production of heavy water.
Hitler's Sunken Secret, a NOVA production airing in November 2005 undertakes a forensics approach to evaluate the heavy water threat.
Brun, Jomar. Brennpunkt Vemork 1940-1945. , 119 pages (1985), Universitetsforlaget.
1909 births
1993 deaths
Austrian nuclear physicists
Austrian emigrants to the United States
Nuclear program of Nazi Germany
Austrian physical chemists
American physical chemists
American nuclear physicists
Members of the United States National Academy of Sciences
Scientists from Vienna
Recipients of the V. M. Goldschmidt Award
20th-century American chemists | Hans Suess | [
"Chemistry"
] | 835 | [
"Geochemists",
"Recipients of the V. M. Goldschmidt Award"
] |
47,365,088 | https://en.wikipedia.org/wiki/Merritt%20engine | The Merritt engine is a design conceived by Dan Merritt, an engineer at Coventry University. Rather than being entirely new, it is a development of the standard petrol engine. The engine is intended to provide "diesel levels of efficiency through a lean-burn strategy similar to that of direct injection". Merritt proposes that fuel/air mixing is not done in the cylinder, but takes place beforehand in a special chamber designed to promote swirl.
The Merritt technique is also known as MUSIC – for Merritt Unthrottled Spark Ignition Combustion. Brian Knibb, an engineer in Derby, UK, says it is relatively straightforward to modify existing engines to run in this way. “To produce MUSIC engines, a factory would simply need to change the cylinder head fitted to engines, leaving the cylinders and the rest unchanged.”
References
Engines | Merritt engine | [
"Physics",
"Technology"
] | 164 | [
"Physical systems",
"Machines",
"Engines"
] |
47,365,198 | https://en.wikipedia.org/wiki/Baggio%E2%80%93Yoshinari%20syndrome | Baggio–Yoshinari syndrome, formerly known as the Brazilian Lyme-like disease and Brazilian human borreliosis, is a disease transmitted by the bites of Amblyomma and Rhipicephalus genera ticks, but the organism that causes the infection is a distinct variant of the bacteria that causes Lyme with different markers that cannot be reliably detected by the standard North American tests. Clinical features resemble those of Lyme disease (LD) but have distinctive differences.
Presentation
A distinct feature of the syndrome is its prolonged clinical evolution, with relapsing episodes and autoimmune dysfunction. If diagnosed in its early stages, the symptoms respond well to antibiotics. If the disease evolves to a chronic phase, it can potentially cause oligoarthritis, cognitive impairment, meningoencephalitis and erythema nodosum, with the patient risking to develop both articular and neurological sequelae.
The neurological manifestations of BYS were first described by Yoshinari et al. including patients with peripheral neuritis, meningitis and cranial neuritis (facial nerve palsy, diplopia and deafness).
Likely transmission vectors of BYS belong to the Amblyomma and Rhipicephalus genera, which could help to explain all the particularities observed in BYS versus LD.
Some features of BYS also resemble those found in the Southern tick-associated rash illness (STARI, also known as Masters' disease), which is found in the Southern USA. However, there are distinctive differences; e.g. the systemic symptoms present with BYS but not with STARI.
Diagnosis
History
In 1989, Brazilian researchers Professors Domingos Baggio (an entomologist from the Biomedical Sciences Institute of the University of São Paulo), Paulo Yasuda (a microbiologist from the same institute) and Natalino Hajime Yoshinari (a physician from the Rheumatology Department at University of São Paulo's Medical School) started research on Lyme disease in Brazil, by suggestion of Dr. Allen Steere. At that time, LD was almost unknown among Brazilian physicians.
The first cases were described in Brazil in 1992 in siblings from Cotia, São Paulo that developed symptoms as a migrating redness, general flu-like symptoms and arthritis after being bitten by ticks. Although the symptoms were similar to those presented by patients of Lyme disease, clinical and laboratorial results were considerably different. Ticks of the Ixodes ricinus complex were not found at the risk areas; bacteria from the Borrelia burgdorferi sensu lato complex —that cause Lyme disease— were not found in biological fluids and tissues of the siblings. Blood analysis of the patients on electron microscopy exhibited structures resembling microorganisms of the spirochaete phylum. For these reasons, the Brazilian zoonosis was considered a new disease and named Baggio–Yoshinari Syndrome (BYS), defined as: "Exotic and emerging Brazilian infectious disease, transmitted by ticks not belonging to the Ixodes ricinus complex, caused by latent spirochetes with atypical morphology, which originates LD-like symptoms, except for occurrence of relapsing episodes and auto-immune disorders".
References
Bacterial diseases
Neurodegenerative disorders
Tick-borne diseases
Syndromes caused by microbes | Baggio–Yoshinari syndrome | [
"Biology"
] | 690 | [
"Microorganisms",
"Syndromes caused by microbes"
] |
47,365,654 | https://en.wikipedia.org/wiki/FG-36 | The FG-36 (AKA Fengyun 2 AKM) was a Chinese spin stabilized apogee kick motor burning HTPB-based composite propellant. It was developed by China Hexi Chemical and Machinery Corporation (also known as the 6th Academy of CASIC) for use in the Fengyun 2 satellite bus for insertion into GSO orbit.
It has a total nominal mass of , of which is propellant load and its burn out mass is . It has an average thrust of with a specific impulse of 289 seconds burning for 43 seconds, with a total impulse of . While it was designed as an apogee kick motor and as such it flew in spin stabilized mode, it was also adapted to the Long March 1D third stage. It was paired with a RCS in a similar solution to the CTS.
See also
Fengyun 2
Long March 1D
CTS
References
Rocket engines of China
Solid-fuel rockets | FG-36 | [
"Astronomy"
] | 191 | [
"Rocketry stubs",
"Astronomy stubs"
] |
47,366,037 | https://en.wikipedia.org/wiki/Olin%20Palladium%20Award | The Olin Palladium Award (formerly the Palladium Medal Award) was established by The Electrochemical Society (ECS) in 1950 and is presented every 2 years to recognize outstanding contributions to the fundamental understanding of all types of electrochemical and corrosion phenomena and processes.
The award consists of a uniquely designed palladium medal bearing the medalist’s name. The design of the medal depicts Pallas Athene employing a shield, on which the seal of the Society is inscribed, to protect the metals represented by ancient symbols from the elements, earth, air, fire, and water. Recipients are also presented with a wall plaque, cash prize, Electrochemical Society Life membership, and a free meeting registration.
History
The Palladium Medal Award was initially funded by the royalties derived from the sales of the Corrosion Handbook and a gift of palladium metal from the International Nickel Company. The original purpose of the medal was to encourage research and achievement in the study of the corrosion of metals and its control, or in theoretical electrochemistry upon which the understanding of corrosion is based.
In 1971 the scope was modified, and in 1977 the name was changed to The Olin Palladium Award after a generous endowment from the Olin Company.
Recipients
As listed by ECS:
2019 Shimshon Gottesfeld
2017 Philippe Marcus
2015 Digby MacDonald
2013 Ralph E. White
2011 Koji Hashimoto
2009
2007 Sergio Trasatti
2005 Robert A. Rapp
2003 Eliezer Gileadi
2001 Norio Sato
1999 John B. Goodenough
1997 Royce W. Murray
1995 Jerome Kruger
1993 Jean-Michel Savéant
1991 John S. Newman
1989 Brian Evans Conway
1987 Allen J. Bard
1985 Martin Fleischmann
1983 Morris Cohen
1981 Izaak Kolthoff
1979 Roger Parsons
1977 Heinz Gerischer
1975 Marcel Pourbaix
1973 Veniamin Levich
1971 Leo Brewer
1969 Thomas P. Hoar
1967 Paul Delahay
1965 Norman Hackerman
1961 Herbert H. Uhlig
1959 Alexander Frumkin
1957 Karl-Friedrich Bonhoeffer
1955 Ulick Richardson Evans
1953 Nathaniel H. Furman
1951 Carl Wagner
See also
List of chemistry awards
References
External links
Olin Palladium Award
Chemistry awards
Awards established in 1951 | Olin Palladium Award | [
"Technology"
] | 447 | [
"Science and technology awards",
"Chemistry awards"
] |
47,367,122 | https://en.wikipedia.org/wiki/Chuan%20He | Chuan He () is a Chinese-American chemical biologist. He currently serves as the John T. Wilson Distinguished Service Professor at the University of Chicago, and an Investigator of the Howard Hughes Medical Institute. He is best known for his work in discovering and deciphering reversible RNA methylation in post-transcriptional gene expression regulation. He was awarded the 2023 Wolf Prize in Chemistry for his work in discovering and deciphering reversible RNA methylation in post-transcriptional gene expression regulation in addition to his contributions to the invention of TAB-seq, a biochemical method that can map 5-hydroxymethylcytosine (5hmC) at base-resolution genome-wide, as well as hmC-Seal, a method that covalently labels 5hmC for its detection and profiling.
Education
He graduated from the University of Science and Technology of China in 1994 with a Bachelor of Science in Chemistry. After undergoing his Ph.D. training with Stephen J. Lippard at the Massachusetts Institute of Technology, he worked under Gregory L. Verdine as a Damon Runyon Postdoctoral Fellow at Harvard University. He subsequently became a faculty member in the Department of Chemistry at the University of Chicago in 2002.
Research
In 2010, He proposed that RNA modifications could be reversible and may have regulatory roles. He and colleagues subsequently discovered the first RNA demethylase that oxidatively reverses N6-methyladenosine (m6A) methylation in mammalian messenger RNA (mRNA) in 2011. The existence of m6A in mRNA was discovered in 1974 in both eukaryotic and viral mRNAs; however, the biological significance and functional role were not known before He’s work. This methylation is the most abundant internal modification in mammalian mRNA. In 2012, two independent studies reported transcriptome-wide mapping of m6A in mammalian cells and tissues, revealing a unique distribution pattern. He and co-workers identified and characterized the direct reader proteins for m6A, which impact the stability and the translation efficiency of m6A-modified mRNA, elucidating functional roles of mRNA methylation. His group also purified the methyltransferase complex that mediates this methylation.
The He laboratory also studies DNA methylation. He invented TAB-seq, a method that can map 5-hydroxymethylcytosine (5hmC) at base-resolution genome-wide, as well as hmC-Seal, a method that covalently labels 5hmC for its detection and profiling. Together with two other research groups, He and co-workers have revealed the DNA N6-methyldeoxyadenosine as a new methylation mark that could affect gene expression in eukaryotes.
Honors and awards
2003: Searle Scholar Award
2005: Beckman Young Investigators Award
2017: Paul Marks Prize for Cancer Research
2019: ACS Chemical Biology Lectureship
2018: Ray Wu Award
2023: Wolf Prize in Chemistry
References
External links
He Lab at The University of Chicago
1972 births
Living people
21st-century American biochemists
American geneticists
Biologists from Guizhou
Chemical biologists
Chemists from Guizhou
Chinese emigrants to the United States
Educators from Guizhou
Harvard University faculty
Howard Hughes Medical Investigators
Massachusetts Institute of Technology alumni
University of Chicago faculty
University of Science and Technology of China alumni | Chuan He | [
"Chemistry"
] | 687 | [
"Chemical biologists"
] |
47,368,410 | https://en.wikipedia.org/wiki/Kathryn%20E.%20Hare | Kathryn Elizabeth Hare (born 1959) is a Canadian mathematician specializing in harmonic analysis and fractal geometry. She was the Chair of the Pure Mathematics Department at the University of Waterloo from 2014 to 2018. She retired from the University of Waterloo in 2021.
Education and career
Hare did her undergraduate studies at the University of Waterloo, graduating in 1981. She earned a Ph.D. from the University of British Columbia in 1986. Her dissertation, under the supervision of John J. F. Fournier, was Thin Sets and Strict-Two-Associatedness, and concerned group representation theory.
She was an assistant professor at the University of Alberta from 1986 to 1988, before she moved back to Waterloo.
Awards and recognition
In 2011, the Chalmers University of Technology awarded her an Honorary Doctorate for her "prominent research, both in extent and depth, within classical and abstract harmonic analysis". In 2020 she was named as a Fellow of the Canadian Mathematical Society.
Selected publications
.
.
.
References
20th-century Canadian mathematicians
21st-century Canadian mathematicians
Mathematical analysts
University of Waterloo alumni
University of British Columbia alumni
Academic staff of the University of Waterloo
1959 births
Living people
20th-century women mathematicians
21st-century Canadian women mathematicians
Fellows of the Canadian Mathematical Society | Kathryn E. Hare | [
"Mathematics"
] | 245 | [
"Mathematical analysis",
"Mathematical analysts"
] |
47,369,663 | https://en.wikipedia.org/wiki/Flail%20space%20model | The flail space model (FSM) is a model of how a car passenger moves in a vehicle that collides with a roadside feature such as a guardrail or a crash cushion. Its principal purpose is to assess the potential risk of harm to the hypothetical occupant as he or she impacts the interior of the passenger compartment and, ultimately, the efficacy of an experimental roadside feature undergoing full-scale vehicle crash testing.
The FSM eliminates the complexity and expense of using instrumented anthropometric dummies during the crash test experiments. Furthermore, while crash test dummies were developed to model collisions between vehicles, they are not accurate when used for the sorts of collision angles that occur when a vehicle collides with a roadside feature; by contrast, the FSM was designed for such collisions.
History
The FSM is based on research performed at Southwest Research Institute in 1980 and published in 1981 in the paper entitled "Collision Risk Assessment Based on Occupant Flail-Space Model" by Jarvis D. Michie. The FSM (coined by Michie) was accepted by the highway community and published as a key part of the "Recommended Procedures for the Safety Evaluation of Highway Appurtenances" published in 1981 in National Cooperative Highway Research Program (NCHRP) Report 230. In 1993, the NCHRP Report was updated and presented as NCHRP Report 350; in this research effort performed by the Texas Transportation Research Institute, the FSM was reexamined and was unmodified in the new publication. In 2004, Douglas Gabauer further examined the efficacy of the FSM in his PhD thesis. The American Association of State Highway and Transportation Officials (AASHTO) retained the FSM as the method of assessing the risk of harm to vehicle occupants in the 2009 "Manual for Assessing Safety Hardware" that replaced NCHRP Report 350, stating that the FSM had "served its intended purpose well".
Details
The FSM hypothesis divides the collision into two stages. In stage one, the unrestrained occupant is propelled forward and sideways in the compartment space due to vehicle collision accelerations and then impacts one or more surfaces (including the steering wheel) with velocity "V". According to the model, the vehicle (instead of the occupant) is the object that is accelerating. The occupant experiences no injury-producing force prior to contact with the compartment surfaces.
In stage two, the occupant is assumed to remain in contact with the compartment surface and experiences the same accelerations as the vehicle for the rest of the collision. The occupant may sustain injury at the end of stage one based on the velocity of impact with the compartment surfaces and due to vehicle accelerations during stage two. The occupant impact velocity and acceleration are computed from the vehicle collision acceleration history and the compartment geometry. Finally, the hypothetical occupant impact velocity and acceleration are then compared to threshold values of human tolerance to these forces.
References
Scientific models
Applied mathematics
Mathematical modeling
Transport safety | Flail space model | [
"Physics",
"Mathematics"
] | 627 | [
"Mathematical modeling",
"Applied mathematics",
"Transport safety",
"Physical systems",
"Transport"
] |
47,369,768 | https://en.wikipedia.org/wiki/Artmotion | Artmotion Ltd. is a Swiss-based data housing provider. It operates two data centers near the Swiss Alps that are designed for security-seeking businesses, motivated by the country's political neutrality and ironclad privacy laws.
History
Artmotion was founded in 2000 by Mateo Meier, who is also the current CEO of the company. In 2003, Artmotion acquired Cyberhost, a Swiss Cloud hosting services provider. Since 2011, the Swiss data center provider Everyware Ltd. holds 25% of Artmotion's shares. Artmotion increased its capital in 2015.
Artmotion acquired 58% of shares in Citadelo and became a shareholder and board member in 2020. However Artmotion and Citadelo continued to operate as separate companies. Artmotion also owns a stake in Citadelo Switzerland.
NSA PRISM scandal
After the 2013 PRISM leak, several cloud computing companies faced criticism for their lack of security, especially those based in US. Artmotion, among other Swiss-based cloud computing providers gained the most out of this scandal. Mostly due to the country's stringent data privacy laws, their customer base increased and the company had their revenue increased 45 percent in a month following the scandal.
According to the CEO Mateo Meier, except in a few European countries like Luxembourg and Switzerland, personal privacy is difficult to service in this modern world. Switzerland is not a member of European Union, hence it is exempt from pan-European agreements to share data with member states, as well as the United States.
References
Information technology companies of Switzerland
Companies based in the canton of Zug
Data centers
Cloud computing providers
Swiss companies established in 2000
Technology companies established in 2000 | Artmotion | [
"Technology"
] | 340 | [
"Data centers",
"Computers"
] |
47,370,141 | https://en.wikipedia.org/wiki/Suillus%20borealis | Suillus borealis is a species of bolete fungus in the family Suillaceae. Found in western North America where it associates with western white pine (Pinus monticola), the fungus was described as new to science in 1965 by mycologists Alexander H. Smith, Harry Delbert Thiers, and Orson K. Miller. It is similar in appearance to Suillus luteus, but unlike in that species, the partial veil does not form a ring on the stipe.
The species is considered to be an excellent edible mushroom.
See also
List of North American boletes
References
External links
borealis
Edible fungi
Fungi described in 1965
Fungi of the United States
Fungi without expected TNC conservation status
Fungus species | Suillus borealis | [
"Biology"
] | 148 | [
"Fungi",
"Fungus species"
] |
47,370,794 | https://en.wikipedia.org/wiki/Plunge%20dip | A plunge dip (also known as a dipping vat, dipping tank or, simply, a dip) is a bath designed to immerse livestock in liquid pesticide or other treatment.
Design
Typically a dip is designed as a narrow channel (about the width of the animal) through which the animals walk, immersing them in progressively deeper liquid until the animal is completely immersed (apart from its head so it can breathe). The channel then becomes progressively shallower until the animal exits. Because many animals can walk through the channel one after another, it is an efficient method of delivering pesticide or other liquid treatments to a large herd.
A liquid product used to treat the livestock by immersion in a plunge dip is also known as a dip (e.g. sheep dip).
See also
R v Korsten
Cattle drenching
References
External links
Animal husbandry
Pesticides
Bathing
Agricultural buildings | Plunge dip | [
"Biology",
"Environmental_science"
] | 181 | [
"Biocides",
"Toxicology",
"Pesticides"
] |
47,371,142 | https://en.wikipedia.org/wiki/Penicillium%20resticulosum | Penicillium resticulosum is an anamorph species of fungus in the genus Penicillium which produces notatin.
References
Further reading
resticulosum
Fungi described in 1942
Fungus species | Penicillium resticulosum | [
"Biology"
] | 44 | [
"Fungi",
"Fungus species"
] |
47,371,486 | https://en.wikipedia.org/wiki/Immunologic%20checkpoint | An immune checkpoint regulator is a modulator of the immune system, that allows initiation of a productive immune response and prevents the onset of autoimmunity. Examples of such a molecule are cytotoxic T-lymphocyte antigen 4 (CTLA-4 or CD152), which is an inhibitory receptor found on immune cells and programmed cell death 1 (CD279), which has an important role in down-regulating the immune system by preventing the activation of T-cells.
Tumours involve certain immune-checkpoint pathways as a major mechanism of immune resistance, particularly against T cells that are specific for tumor antigens. Therefore, the strategy in using immunological checkpoints in cancer therapy is to inhibit inhibitory molecules of the immune system, thus stimulating the immune system. The ability to interfere with the inhibitory function of checkpoint receptors CD152 and CD279 (programmed death-1) in oncology has proved successful. In metastatic melanoma FDA approved an αCD152 monoclonal antibody Ipilimumab, that was found to prolong survival. In melanoma, nonsmall cell lung cancer, and renal cell carcinoma there is hope with CD279 blocking Ab, that promotes antitumor responses. In hematologic malignancies a humanized αCD279 IgG1 needs further research. In solid tumors the use of CD279 IgG4 Ab is promising, and further CD273/PD-L2 in stage IV.
In autoimmune rheumatic diseases, impaired tolerance leads to the development of diseases such as rheumatoid arthritis, systemic sclerosis, systemic lupus erythematosus, Sjogren’s syndrome, etc. Therefore, in autoimmune diseases the converse strategy of engaging immunological checkpoints may be beneficial: stimulate inhibitory molecules of the immune system, thus inhibiting the immune system (therefore, increase self-tolerance). What is known to work is Abatacept, an CD152-Ig used in treating rheumatoid arthritis and juvenile idiopathic arthritis.
Not studied enough yet are the therapeutic opportunities using Programmed death-1 pathway.
References
Immunology | Immunologic checkpoint | [
"Biology"
] | 463 | [
"Immunology"
] |
47,372,547 | https://en.wikipedia.org/wiki/Truncated%20Newton%20method | The truncated Newton method, originated in a paper by Ron Dembo and Trond Steihaug, also known as Hessian-free optimization, are a family of optimization algorithms designed for optimizing non-linear functions with large numbers of independent variables. A truncated Newton method consists of repeated application of an iterative optimization algorithm to approximately solve Newton's equations, to determine an update to the function's parameters. The inner solver is truncated, i.e., run for only a limited number of iterations. It follows that, for truncated Newton methods to work, the inner solver needs to produce a good approximation in a finite number of iterations; conjugate gradient has been suggested and evaluated as a candidate inner loop. Another prerequisite is good preconditioning for the inner algorithm.
References
Further reading
Optimization algorithms and methods | Truncated Newton method | [
"Mathematics"
] | 175 | [
"Applied mathematics",
"Applied mathematics stubs"
] |
47,372,733 | https://en.wikipedia.org/wiki/Irene%20Manton%20Prize | The Irene Manton Prize of the Linnean Society of London is awarded annually for the "best thesis in botany examined for a doctorate of philosophy during a single academic year" in the United Kingdom.
The prize is named in honour of Irene Manton FRS, the first female president of the Linnean Society of London. She pioneered the biological use of electron microscopy. Her work revealed the structure of the flagellum and cilia, which are central to many systems of cellular motility.
Recipients of the Irene Manton Prize
Tin Hang Hung (2024) University of Oxford; Ecological genomics and adaptation of rosewoods Dalbergia cochinchinensis and D. oliveri for conservation and restoration
Brogan Harris (2023) University of Bristol; A phylogenetic investigation into the evolutionary history of stomata and land plants
Bruno Pok Man Ngou (2022) University of East Anglia & The Sainsbury Laboratory; Roles and mechanisms of effector-triggered immunity in plant disease resistance
Sophie Harrington (2021) University of East Anglia; Understanding the molecular and genetic mechanisms regulating senescence in wheat
James Clark (2020) University of Bristol; Whole genome duplication and the evolution of the land plant body plan
Leanne Melbourne (2019) University of Bristol; The effect of environmental change on the structure, composition and subsequently the structural integrity of un-attached corallines
Sandy Hetherington (2018) University of Oxford; Evolution and morphology of lycophyte root systems
Shanna Ludwig (2015) University of Bristol; Ecological and evolutionary genetics, focusing on reproductive biology and speciation in diploid and polyploid Sorbus populations
Simon Renny-Byfield (2014) Queen Mary, University of London; Evolution of repetitive DNA in angiosperms: Examples from Nicotiana
Janine Pendleton (2013) University of Sheffield; Carboniferous plants and spores from the Bristol Coalfield
Alexander S T Papadopulos (2012) Imperial College London
Tiina Sarkinen (2011)
Christopher Thorogood (2010) University of Bristol
Chris Yesson (2009)
James Clarkson and Silvia Pressel (2008)
Lionel Navarro (2007) University of East Anglia; Plant innate immunity and bacterial pathogenesis
Yuki Yasumura (2006) University of Oxford
Alex Wortley (2005)
Mark Clegg (2003)
Julie King (2002)
Alison Gwen Roberts (2001)
James Edward Richardson (2000)
Melissa Spielman (1999)
Alexander Weir (1998)
Colin Edward Hughes (1997)
Dorothy Steane (1996)
Sally Glockling (1995)
William Justin Goodrich (1993)
Sharon Anita Robinson and Robert Winning Scotland (1992)
not awarded (1991)
Christine Masterson (1990)
See also
List of biology awards
References
British science and technology awards
Biology awards | Irene Manton Prize | [
"Technology"
] | 558 | [
"Science and technology awards",
"Biology awards"
] |
47,372,849 | https://en.wikipedia.org/wiki/Trail-Crisp%20Award | The Trail-Crisp Award, of the Linnean Society of London, was established in 1966 and is an amalgamation of The Trail Award and The Crisp Award (both founded in 1910).
The Trail-Crisp Award is presented at intervals "in recognition of an outstanding contribution to biological microscopy that has been published in the UK".
Recipients
Trail Award
1915: Leonard Doncaster
1920: Helen Gwynne-Vaughan
1937: Carl Pantin
1948: Honor Fell
1954: Irene Manton
1960: L.E.R. Picken
Trail-Crisp Award
See also
List of biology awards
References
Biology awards
Biology in the United Kingdom
British science and technology awards
Linnean Society of London | Trail-Crisp Award | [
"Technology"
] | 136 | [
"Science and technology awards",
"Biology awards"
] |
47,372,902 | https://en.wikipedia.org/wiki/M85-HCC1 | M85-HCC1 is an ultracompact dwarf galaxy with a star density 1,000,000 times that of the solar neighbourhood, lying near the galaxy Messier 85. , it is the densest galaxy known.
See also
List of most massive galaxies
References
See also
M59-UCD3 (second-densest galaxy known, as of 2015)
M60-UCD1 (another dense galaxy)
Dwarf galaxies
20150727
Coma Berenices | M85-HCC1 | [
"Astronomy"
] | 98 | [
"Coma Berenices",
"Galaxy stubs",
"Astronomy stubs",
"Constellations"
] |
47,372,974 | https://en.wikipedia.org/wiki/C5H8N2O4 | {{DISPLAYTITLE:C5H8N2O4}}
The molecular formula C5H8N2O4 (molar mass: 160.13 g/mol, exact mass: 160.0484 u) may refer to:
Thymine glycol (5,6-dihydroxy-5,6-dihydrothymine)
Tricholomic acid | C5H8N2O4 | [
"Chemistry"
] | 86 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
47,373,307 | https://en.wikipedia.org/wiki/AK%20Pyxidis | AK Pyxidis is a semiregular variable star located in the constellation Pyxis. It varies between magnitudes 6.09 and 6.51, making it very faintly visible to the naked eye under excellent dark sky conditions. It has been found to pulsate with periods of 55.5, 57.9, 86.7, 162.9 and 232.6 days simultaneously. Located around 1228 light-years distant, it shines with a luminosity approximately 1500 times that of the Sun and has a surface temperature of 3410 K.
The variability of AK Pyxidis was discovered during the analysis of the Hipparcos satellite data. It was given the variable star designation AK Pyxidis in 1999.
References
Pyxis
Semiregular variable stars
M-type giants
Pyxidis, AK
Durchmusterung objects
75306
043215 | AK Pyxidis | [
"Astronomy"
] | 186 | [
"Pyxis",
"Constellations"
] |
47,374,133 | https://en.wikipedia.org/wiki/Creepy%20treehouse | Creepy treehouse is a social media term, or internet slang, referring to websites or social networking platforms that professors use for educational purposes, but students regard as an invasion of privacy.
History
The term was first described in 2008 by Utah Valley University instructional-design services director Jared Stein as "institutionally controlled technology/tool that emulates or mimics pre-existing technologies or tools that may already be in use by the learners, or by learners’ peer groups." This was when social media such as Facebook was starting to become mainstream and professors would try and get students to interact with them on the site for educational purposes. Some professors would require their students to use Facebook or Twitter as part of class assignments.
Usage
The term was first described as "technological innovations by faculty members that make students’ skin crawl." The term also refers to online accounts and websites that users tend to avoid, especially young people who avoid visiting the pages of educators and other adults. Author Martin Weller defines creepy treehouse as a digital space where authority figures are viewed as invading younger people's privacy. One such example is a professor giving his students an option to use a popular video game to learn about history instead of writing an essay. Students in that class chose to write the essay instead as the method was previously unmentioned and it was not an unnatural method of interaction. Another example given was Blackboard Sync, a feature that was used to connect the school website Blackboard with students' Facebook accounts.
Solutions
University of Regina professor Alec Couros suggests that instead of "forcing" student participation with their own digital platforms, professors should use methods like online forums. Jason Jones of chronicle.com suggested letting students create social media groups for the class themselves and explaining why using technologies is required and important.
See also
Web 2.0
Discussion boards
Digital learning
References
Internet culture
Internet forum terminology
Social media | Creepy treehouse | [
"Technology"
] | 376 | [
"Computing and society",
"Social media"
] |
47,375,191 | https://en.wikipedia.org/wiki/Dyadic%20space%20%28cell%20biology%29 | The dyadic space is the name for the volume of cytoplasm between pairs (dyads) of areas where the cell membrane and an organelle such as the endoplasmic reticulum (or sarcoplasmic reticulum) come into close contact (within 10-12 nanometers) of each other, creating what are known as dyadic clefts.
The space is important for ionic signalling. For example, the phenomenon of calcium-induced calcium release, when extracellular calcium enters the cell through ion channels in T-Tubules, leading to a rapidly increased calcium concentration in the dyadic space, triggering ryanodine receptors on the sarcoplasmic reticulum to release more calcium and trigger cardiac myocyte contraction - the heart beat.
References
Cell biology
Cell anatomy | Dyadic space (cell biology) | [
"Biology"
] | 171 | [
"Cell biology"
] |
47,375,779 | https://en.wikipedia.org/wiki/Joaquim%20Gomes%20de%20Souza | Joaquim Gomes de Souza "Souzinha" (15 February 1829, in Itapecuru Mirim – 1 June 1864, in London) was a Brazilian mathematician who worked on numerical analysis and differential equations. He was a pioneer on the study of mathematics in Brazil, and was described by José Leite Lopes as "the first great mathematician from Brazil".
In 1844, Gomes de Souza enrolled at the Faculdade de Medicina do Rio de Janeiro (now a part of the Federal University of Rio de Janeiro) to study medicine. He had a deep love for the natural sciences, which led him to also be interested in mathematics, and so he started to learn mathematics as a self-taught in parallel with his studies of medicine.
In 1848, he obtained his doctorate in mathematics from the Escola Real Militar, with the thesis Dissertação Sobre o Modo de Indagar novos Astros sem o Auxílio das Observações Directas (Dissertation about the means of investigating new celestial objects without the aid of direct observations).
He later went to the Sorbonne, in France, where he continued his mathematical studies. He was a personal friend of Cauchy, of whose classes he attended (in one of them, Souza spotted a mathematical mistake by Cauchy, he then asked his license and corrected it on the blackboard). In 1856, he obtained a doctorate in medicine from Paris Faculty of Medicine. In the same year, he presented his mathematical works at the Académie des sciences.
Souza held a paid public post in Brazil, and after much time in Europe, he was noticed he should return immediately to Brazil because he had been elected a member of the parliament. Souza had already married Rosa Edith in England and then had to return to Brazil without her.
In his book Mélanges de calcul intégral (1882), Souza aimed to obtain a general method to solve PDEs, according to Manfredo do Carmo: "[in his book] He [Souza] employed methods not entirely rigorous and it is not clear exactly how much of his work would remain if submitted to a careful scrutiny; as far as I know, it was never put to such a test."
He died at the age of 35, in London. The cause of death was a disease of the lung. C. S. Fernandez and C. M. Souza described his endeavorer in Europe: "He was audacious and fought with insistence for his scientific recognition in Europe. His effort was fruitless, though."
Writings
Resoluções das Equações Numéricas (1850, in Portuguese)
Recuel de Memoires d’Analise Mathematiques (1857, in French)
Anthologie universelle (1859, in French)
Mélanges de calcul intégral (1882, posthumous, in French)
Further reading
Irine Coelho de Araujo, Joaquim Gomes de Souza (1829-1864): A construção de uma imagem de Souzinha, São Paulo, 2012
Carlos Ociran Silva Nascimento, Alguns aspectos da obra matematica de Joaquim Gomes de Souza, Campinas, 2008
References
1829 births
1864 deaths
Brazilian mathematicians
Brazilian politicians
Mathematical analysts
Partial differential equation theorists
Federal University of Rio de Janeiro alumni | Joaquim Gomes de Souza | [
"Mathematics"
] | 692 | [
"Mathematical analysis",
"Mathematical analysts"
] |
67,170,495 | https://en.wikipedia.org/wiki/Tsou%20plot | The Tsou plot is a graphical method of determining the number and nature of the functional groups on an enzyme that are necessary for its catalytic activity.
Theory of Tsou's method
Tsou Chen-Lu analysed the relationship between the functional groups of enzymes that are necessary for their biological activity and the loss of activity that occurs when the enzyme is treated with an irreversible inhibitor. Suppose now that there are groups on each monomeric enzyme molecule that react equally fast with the modifying agent, and of these are essential for catalytic activity. After modification of an average of groups on each molecule, the probability that any particular group has been modified is and the probability that it remains unmodified is . For the enzyme molecule to retain activity, all of its essential groups must remain unmodified, for which the probability is . The fraction of activity remaining after modification of groups per molecule must be
and so
This means that a plot of against should be a straight line. As the value of is initially unknown one must draw plots with values 1, 2, 3, etc. to see which one gives a straight line.
There are various complications with this analysis, as discussed in the original paper, and, more recently in a textbook.
Experimental applications
Despite the possible objections, the Tsou plot gave clear results when applied by Paterson and Knowles to inactivation of pepsin by trimethyloxonium tetrafluoroborate (Meerwein's reagent), a reagent that modifies carboxyl residues in proteins. They were able to deduce from this experiment that three non-essential groups are modified without loss of activity, followed by two essential groups — two because assuming yielded a straight line in the plot, whereas values of 1 and 3 yielded curves, with a total of 13 residues modified, as illustrated in the figure.
Tsou's plot has also given good results with other systems, such the type I dehydroquinase from Salmonella typhi, for which modification of just one essential group by diethyl pyrocarbonate was sufficient to inactivate the enzyme.
Alternative approach to the same question
A little before Tsou published his paper William Ray and Daniel Koshland had described a different way of investigating the number and nature of groups on an enzyme essential for activity. Their method depends on kinetic measurements, and cannot be used, therefore, in cases where the modification is too fast for such measurements, such as the case of pepsin discussed above, but it complements Tsou's approach in useful ways.
Suppose that an enzyme has two groups and that are both essential for the catalytic activity, so if either is lost the catalytic activity is also lost. If is converted to an inactive form in a first-order reaction with rate constant , and is inactivated in a first-order reaction with a different rate constant , then the remaining activity after time obeys an equation of the following form:
in which is the value of when and is the observed first-order rate constant for inactivation, the sum of the rate constants for the separate reactions. The equation can be extended in an obvious way to the case more than two groups are essential. Ray and Koshland also described the properties to be observed when not all of the modified groups are essential.
References
Plots (graphics)
Enzyme kinetics | Tsou plot | [
"Chemistry"
] | 683 | [
"Chemical kinetics",
"Enzyme kinetics"
] |
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