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44,437,560 | https://en.wikipedia.org/wiki/Fish%20aggression | Aggression refers to agonistic behaviors characterized by threats and physical force. Methods of aggression in fish vary widely by species, but some common examples are chasing, charging, biting, fin display, color changes, and flared gills. Aggression is an important evolutionary pressure that increases an individual's access to resources while reducing overall conflict within the social group. Fish use aggressive behaviors to defend a territory, establish dominance, appeal to potential mates, and protect their young.
Aggressive behavior comes in two forms: threat displays and attacks. Attacking is how two competitors can directly compare their strength by biting or head-bumping, but it comes with significant drawbacks: it's energetically costly, time consuming, and risking bodily injury. A threat display, on the other hand, allows competitors to assess the other's strength indirectly, making it a safer way to settle conspecific conflict.
During a confrontation, threat displays communicate the factors that would tip a physical fight, such as body-size, dominance status, motivation, and territoriality. While displays are less risky than attacks, they still come with a cost. Many fish will make their heads look larger by pushing out their opercula, but this also makes it difficult to breathe. Aggressive behaviors might invite the attention of predators, and time spent challenging a competitor means time lost foraging, courting, or caring for young. Therefore, some fish will choose to end an aggressive encounter immediately by signaling submission.
Territorial aggression
Fish territories are defended areas generally ruled by a single individual or by breeding pairs. The guarded resource may include food, shelter, sexual partner or offspring. While protecting their regions, fish often display aggressive behavior against their intruders. The territory owner strikes at competing fish directly ending in a bite, or a bump. Such aggressive behavior is seen in large juveniles, females and other fish of the same kind from the same area. For example, the three-spine stickleback (Gasterosteus aculeatus) is polygynous, with males preferring two or more female mates in their territory. Thus, males are highly aggressive so they have access to females in a particular territory, which also leads to intrasexual selection among males. Intrasexual selection is selection within the same sex. For instance, some male animals compete against one another, physically, for access to females for their kind. So, characteristics like a long tail, sharp teeth or similar weaponry that can be used against other males of the same species as means of mating with females is a selective advantage.
There is a deep relationship between the aggression in fish and the size of the regions owned by them. In a smaller territory, female fish often disappear before mating. Female fish are not bound to mate with a particular fish. If by chance a female is attracted to another male, she can dump the previous partner without any hesitation. In this situation, the ditched male fish becomes more aggressive to find mates in order to reproduce. Their levels of aggression increase more when the rates of sneaking by rival males go up too. The sneaking males enter the nest and release their own sperm over the eggs of the breeding fish. The rival fish here are using alternative reproduction methods like parental, sneaker or satellite to avoid being hurt by breeding males. On the other hand, the breeding males have higher mating success and endure less looting of eggs in large territories. Once the eggs have been gathered, the breeding males decrease their territories to protect their offspring from the predators during their parental phase. After the eggs have hatched, the males continue to show similar or more invasive behavior due to increased reproductive value of offspring and the awareness of newly hatched young fish against enemies.
Territorial aggression can take place not only due to the pressure of mating, producing offspring, or intruders, but also from light intensity. The term intensity is used to describe the rate at which light spreads over a surface of a given area some distance from a source. At lower light levels, the risk of losing resources like food and mates gives rise to aggressive behavior among the fish belonging to a territory. Additionally, for further understanding on how the rate of aggression and distance among neighboring fish varies with nighttime light intensities in the same area, Sveinn Valdimarsson and Neil Metcalfe conducted an experiment with the juveniles of Atlantic salmon (Salmo salar). At the beginning, S. salar were exposed to four different nighttime light intensities (0.00, 0.01, 0.50 and 1.00 lx) for 24 hours. From the result, it was concluded that fish showed less aggression when the intensity of the light was lower. This is because when the level of light was intense, due to darkness of night the territorial fish failed to detect their food or other members in the same area. So they decreased their territory size and remained closer to each other rather than attacking. This was a good example of evolution of cooperation among the fish. Additionally, as the light intensities of the light increased, those fish could see each other to defend their space. The territory size increases during bright lights. In short, the aggressive behavior of the salmon toward their rivals is highly manipulated by light intensities. Thus, the size of the space that the fish is defending increases or decreases between day and night.
Sex-specific aggression
Male and female fish both get involved in aggressive confrontation. Yet varying selection pressures affecting each sex result in gender differences in aggressive syndrome during competition. Aggressive syndrome is a social condition describing an individual's need to show his distaste or dislike against certain individuals. Adult female fish usually gather in groups, including adult females and non-reproductive males. Aggressive behavior is displayed in females especially when the female fish attack each other directly. Dominance relationships can take place among female association. For instance, females of higher status (size) have better opportunities to mate than minors residing in the same group. Then females become aggressive when there are two dominant females trying to select the same male fish for mating. This selection can be based on intersexual selection, which is selection between two sexes. Females use such selection while choosing mates with good genes. For example, female peacocks tend to prefer male peacocks with bright plumage. The females think that if they mate with males with bright plumage, the offspring will have similar characteristics.
S. Josefin Dahlbom and colleagues experimented on zebra fish (Danio rerio) to study the difference in aggression level between males and females if they are put together under similar environment. For this test, fish were paired with one of the same sex. As the experiment continued, it was observed that both dominant males and females increase their aggression level until day four. On the fifth day, the dominant female members in the group stopped being aggressive. The authors suggested that this could be because the subordinate females stopped challenging the dominant female early in the study, and thereby the dominant female did not need to prove her superiority. In contrast, male subordinates continued fighting against the dominant males. As a result, the dominant males showed more aggression to suppress the subordinate males and to maintain their position among others.
In the paper ‘Gender differences in aggressive behavior in convict cichlids’ Gareth Arnott and Robert W. Elwood investigated if gender related variations in aggression are seen in convict cichlids (Amatitlania nigrofasciata). To see gender-related changes in aggression, they tested if intersexual agonistic events take place between isolated males and females, who were not previously paired to each other as breeding partners. At the end, it was detected that in terms of encroachment, Texas cichlids males used lateral display along with tail biting; whereas, the females used frontal display with biting. These two different displays have an explanation. Convict cichlids generally use either their left or right eye while swimming. Therefore, these fish use either their left or right hemisphere of the brain. Aggressive males are believed to use only their left hemisphere; whereas, aggressive females navigate based on their right eyes. Although a clear conclusion cannot be drawn from this study between the hemispheres and the aggression levels, it is fairly clear that males and females show variation in aggression syndrome. In short, various forces affecting each sex can result in different aggressive behaviors among male and female fish.
Aggression for genetic makeup
Evolution of aggression can occur in fish due to their genetic makeup. To examine the relationship between aggression and genetic makeup, a team from CNRS/Laboratoire Neurobiologie et Développement conducted an experiment on zebra fish. At the beginning, the team of CNRS organized behavioral tests to quantitatively measure the three characters of aggressive behavior. In the experiment, it turned out that this particular fish has a mutation in its fgfr-1 gene summarizing for a membrane receptor sensitive to FGF (Fibroblast Growth Factor), which is a key for growth factor in those fish. As a reaction to the mutation, this group of fish displays low brain levels of histamine. Histamine is a neurotransmitter that controls appetite, sleep and attention in a species. Due to low histamine levels, zebra fish exhibit aggressive behavior. Therefore, the link between the fgfr-1 genes to histamine regulates the behavioral status of aggression in zebra fish.
In another experiment Katrina Tiira performed a different test on land-locked Atlantic salmon (Salmo salar) to see if juveniles with low estimated genetic diversity showed less aggression. To continue the theory, researchers selected one group of fish with low genetic diversity and another group with high genetic diversity, and compared aggression levels. They observed that salmon fry with low genetic variation showed less aggression than the other group. In the group of less variation, the researcher used closely related parents. The juveniles were genetically related sharing high number of alleles with each other. Thus, they display low aggression to their competitors as they used kin recognition method on others. In conclusion, it can be explained that genetic variation in salmon can manipulate the agnostic syndrome if the individuals in a group are closely related.
Aggression in fish can be increased by the effect of growth hormone, or GH, which has an essential growth factor in this species. They control the use of nutrients in tissue synthesis. Thus, it increases the metabolic demands in species resulting in aggression to fight for daily needs. An experiment was designed on juvenile rainbow trout (Oncorhynchus mykiss). They selected two control fish (C/C pairs), two growth hormone treated fish (GH/GH pairs) or one growth hormone-treated and one control (C/GH pairs). From the testing, it was analyzed that the GH increases aggression levels in all groups of O. mykiss. It indirectly improved the swimming activity along with the attacking rate between competitors. In summary, growth hormone plays a vital role in controlling aggression in rainbow trout and other fish.
References
Aggression
Aggression | Fish aggression | [
"Biology"
] | 2,230 | [
"Behavior",
"Aggression",
"Human behavior"
] |
44,438,716 | https://en.wikipedia.org/wiki/Thielavia%20subthermophila | Thielavia subthermophila is a ubiquitous, filamentous fungus that is a member of the phylum Ascomycota and order Sordariales. Known to be found on plants of arid environments, it is an endophyte with thermophilic properties, and possesses dense, pigmented mycelium. Thielavia subthermophila has rarely been identified as a human pathogen, with a small number of clinical cases including ocular and brain infections. For treatment, antifungal drugs such as amphotericin B have been used topically or intravenously, depending upon the condition.
History
Thielavia subthermophila is a cleistothecial fungus that have a thin peridium, spherical ascoma, and dark-coloured ascospores. It was first described by Jean Mouchacca in 1973 who isolated it from desert soil. To date, there has been confusion in classifying species within the genus Thielavia, as the characteristics of the species are not well-differentiated from perithecial relatives in the genus Chaetomium.
Morphology
Thielavia subthermophila forms grey colonies with a black reverse, with dark brown, hairy, spherical ascomata that are 90–200 μm in diameter and develop within the mycelial mat. The wall of the ascomata is made of textura epidermoidea or flattened and irregularly outlined cells measuring 6–8 μm in diameter, and is covered with dark, branching hyphae. Aleuriospores and chlamydospores are light brown, single-celled, 5–7 × 3–5 μm in diameter, have a truncate base, and grow terminally and laterally on short branches or hyphae. Thielavia subthermophila has asci measuring 20–30 × 15–22.5 μm in diameter, each containing 8 spores. It has single-celled, dark olive to black, fusiform or elliptical ascospores measuring 14–20 × 8–10 μm in diameter with a subapical germ pore measuring 1–1.5 μm in diameter. Compared to other species within the genus Thielavia such as Thielavia arenaria and Thielavia microspora, it is known to produce large ascospores. A felt-like aerial mycelium is characteristic of T. subthermophila, consisting of septate, branched, and hyaline or dark olive hyphae and measuring 1–3 μm.
Growth
Thielavia subthermophila shows optimal growth and survival up to , as determined by its thermotolerant properties, and possesses light-protection structures. The asexual reproductive form of Thielavia subthermophila is associated with production of pale yellowish brown, smooth aleurioconidia measuring 3–4 × 2.5–3 μm in diameter, with no conidiophores present. Sexual reproduction is associated with abundant production of cleistothecia that are brownish black to black, scattered, and 120–180 μm in diameter, covered by dark olive hairs.
Ecology
Thielavia subthermophila has been isolated from a wide range of environments, such as soil, camel hair, and desert vegetation. In addition, it has been found in dried Hibiscus flower, Brazilian pepper seeds, and species of herbal plants such as "Plantaginis herba", "Plantaginis semen", and Abies webbiana. Notably, T. subthermophila has been isolated as an endophyte of Hypericum perforatum, otherwise known as St. John's wort.
Metabolites
Emodin is a fungal metabolite that has been isolated from Thielavia subthermophila, which inhibits the expression of cytokines, chemokines, and inflammatory modulators in vitro. Hypericin is a fungal metabolite that has also been isolated from Thielavia subthermophila, that initiates high cytotoxicity when excited by irradiation with visible light. Thielavia subthermophila isolated from the stems of Hypercium perforatum has been recognized to undergo mechanisms of emodin and hypericin biosynthesis.
Pathology
As with other Thielavia species, Thielavia subthermophila has rarely been identified to be involved in human fungal infections.
Keratitis
Thielavia subthermophila has been recognized to cause ocular infections in humans, as it has been isolated from corneal scrapings of an infected patient, characterized by lesions with central ulceration and ill-defined margins.
Cerebral phaeohyphomycosis
Thielavia subthermophila has been known to cause fatal brain infections in humans, with the first case reported in an immunocompetent, Indian male. In the brain, its growth is known to be associated with fungal granulomas centered around blood vessels and branched fungal hyphae in the parenchyma. Cerebral phaeohyphomycosis due to Thielavia subthermophila is characterized by the production of pus and necrotic tissue in the brain. Symptoms of cerebral phaeohyphomycosis include foaming at the mouth, fever, seizures, involuntary urination, and uncontrolled movement of eyes and limbs.
Treatment
To treat ocular infections, antifungal medication such as oral voriconazole and amphotericin B eyedrops can be administered to the patient. Fortified tobramycin, fortified cefazolin, fluorometholone, and scopolamine eyedrops can also be administered if necessary, depending on the symptoms. In addition, corneal abrasion can be performed on the patient to facilitate penetration of the antifungal medication. Amphotericin B therapy, surgical removal of infected tissue, and immune enhancement can be used to treat cerebral phaeohyphomycosis by Thielavia subthermophila, although despite treatment, is associated with high mortality. Currently, there is no accepted standard treatment for brain infections by T. subthermophila.
References
Sordariales
Fungi described in 1973
Fungus species | Thielavia subthermophila | [
"Biology"
] | 1,306 | [
"Fungi",
"Fungus species"
] |
44,439,173 | https://en.wikipedia.org/wiki/Bradley%E2%80%93Terry%20model | The Bradley–Terry model is a probability model for the outcome of pairwise comparisons between items, teams, or objects. Given a pair of items and drawn from some population, it estimates the probability that the pairwise comparison turns out true, as
where is a positive real-valued score assigned to individual . The comparison can be read as " is preferred to ", " ranks higher than ", or " beats ", depending on the application.
For example, might represent the skill of a team in a sports tournament and the probability that wins a game against . Or might represent the quality or desirability of a commercial product and the probability that a consumer will prefer product over product .
The Bradley–Terry model can be used in the forward direction to predict outcomes, as described, but is more commonly used in reverse to infer the scores given an observed set of outcomes. In this type of application represents some measure of the strength or quality of and the model lets us estimate the strengths from a series of pairwise comparisons. In a survey of wine preferences, for instance, it might be difficult for respondents to give a complete ranking of a large set of wines, but relatively easy for them to compare sample pairs of wines and say which they feel is better. Based on a set of such pairwise comparisons, the Bradley–Terry model can then be used to derive a full ranking of the wines.
Once the values of the scores have been calculated, the model can then also be used in the forward direction, for instance to predict the likely outcome of comparisons that have not yet actually occurred. In the wine survey example, for instance, one could calculate the probability that someone will prefer wine over wine , even if no one in the survey directly compared that particular pair.
History and applications
The model is named after Ralph A. Bradley and Milton E. Terry, who presented it in 1952, although it had already been studied by Ernst Zermelo in the 1920s. Applications of the model include the ranking of competitors in sports, chess, and other competitions, the ranking of products in paired comparison surveys of consumer choice, analysis of dominance hierarchies within animal and human communities, ranking of journals, ranking of AI models, and estimation of the relevance of documents in machine-learned search engines.
Definition
The Bradley–Terry model can be parametrized in various ways. Equation () is perhaps the most common, but there are a number of others. Bradley and Terry themselves defined exponential score functions , so that
Alternatively, one can use a logit, such that
i.e.
for
This formulation highlights the similarity between the Bradley–Terry model and logistic regression. Both employ essentially the same model but in different ways. In logistic regression one typically knows the parameters and attempts to infer the functional form of ; in ranking under the Bradley–Terry model one knows the functional form and attempts to infer the parameters.
With a scale factor of 400, this is equivalent to the Elo rating system for players with Elo ratings and .
Estimating the parameters
The most common application of the Bradley–Terry model is to infer the values of the parameters given an observed set of outcomes , such as wins and losses in a competition. The simplest way to estimate the parameters is by maximum likelihood estimation, i.e., by maximizing the likelihood of the observed outcomes given the model and parameter values.
Suppose we know the outcomes of a set of pairwise competitions between a certain group of individuals, and let be the number of times individual beats individual . Then the likelihood of this set of outcomes within the Bradley–Terry model is and the log-likelihood of the parameter vector is
Zermelo showed that this expression has only a single maximum, which can be found by differentiating with respect to and setting the result to zero, which leads to
This equation has no known closed-form solution, but Zermelo suggested solving it by simple iteration. Starting from any convenient set of (positive) initial values for the , one iteratively performs the update
for all in turn. The resulting parameters are arbitrary up to an overall multiplicative constant, so after computing all of the new values they should be normalized by dividing by their geometric mean thus:
This estimation procedure improves the log-likelihood on every iteration, and is guaranteed to eventually reach the unique maximum. It is, however, slow to converge. More recently it has been pointed out that equation () can also be rearranged as
which can be solved by iterating
again normalizing after every round of updates using equation (). This iteration gives identical results to the one in () but converges much faster and hence is normally preferred over ().
Worked example of solution procedure
Consider a sporting competition between four teams, who play a total of 22 games among themselves. Each team's wins are given in the rows of the table below and the opponents are given as the columns:
For example, Team A has beat Team B twice and lost to team B three times; not played team C at all; won once and lost four times against team D.
We would like to estimate the relative strengths of the teams, which we do by calculating the parameters , with higher parameters indicating greater prowess. To do this, we initialize the four entries in the parameter vector arbitrarily, for example assigning the value 1 to each team: . Then we apply equation () to update , which gives
Now, we apply () again to update , making sure to use the new value of that we just calculated:
Similarly for and we get
Then we normalize all the parameters by dividing by their geometric mean to get the estimated parameters .
To improve the estimates further, we repeat the process, using the new values. For example,
Repeating this process for the remaining parameters and normalizing, we get . Repeating a further 10 times gives rapid convergence toward a final solution of . This indicates that Team D is the strongest and Team B the second strongest, while Teams A and C are nearly equal in strength but below Teams B and D. In this way the Bradley–Terry model lets us infer the relationship between all four teams, even though not all teams have played each other.
Variations
Crowd-BT
The Crowd-BT model, developed in 2013 by Chen et al, attempts to extend the standard Bradley–Terry model for crowdsourced settings while reducing the number of comparisons needed by taking into account the reliability of each judge. In particular, it identifies and excludes judges presumed to be spammers (selecting choices at random) or malicious (selecting always the wrong choice). In a crowdsourced task of ranking documents by reading difficulty with 624 judges contributing up to 40 pairwise comparisons each, Crowd-BT was shown to outperform both standard Bradley–Terry as well as ranking system TrueSkill. It has been recommended for use when quality results are valued over efficiency and the number of comparisons is high.
See also
Ordinal regression
Rasch model
Scale (social sciences)
Elo rating system
Thurstonian model
References
Machine learning
Statistical models
Logistic regression
Regression models | Bradley–Terry model | [
"Engineering"
] | 1,435 | [
"Artificial intelligence engineering",
"Machine learning"
] |
44,441,142 | https://en.wikipedia.org/wiki/Robert%20R.%20Squires | Robert Reed Squires (January 11, 1953 – September 30, 1998) was an American chemist known for his work in gas phase ion chemistry and flowing afterglow mass spectrometry.
Early life and education
Squires was born in Northern California and grew up in Los Angeles. He received an A.A. degree at El Camino College in 1973 and then returned to Northern California where he received a B.A. at California State University, Chico. He then went on to Yale University where he worked in the laboratory of Kenneth B. Wiberg on the thermochemistry of organic compounds. He received his M.Phil. degree in 1977 and a Ph.D. in 1980. He took a postdoctoral position with Charles DePuy and Veronica Bierbaum at the University of Colorado, Boulder where he studied the reactions of gas-phase ions using the flowing afterglow technique.
Academic career
Squires took a position as an assistant professor at Purdue University in 1981 where he constructed two unique mass spectrometers: a flowing afterglow triple quadrupole mass spectrometer and a flowing afterglow selected ion flow tube triple quadrupole mass spectrometer. In 1986, he was promoted to Associate Professor and in 1990 to Professor.
Awards
Among his awards were an Alfred P. Sloan Foundation Fellowship in 1987, the American Chemical Society Nobel Laureate Signature Award for Graduate Education in Chemistry (with Susan Graul) in 1991, and the American Society for Mass Spectrometry Biemann Medal in 1998. The Purdue University Department of Chemistry Robert R. Squires Scholarship was established in his honor.
References
1953 births
1998 deaths
20th-century American chemists
Mass spectrometrists | Robert R. Squires | [
"Physics",
"Chemistry"
] | 347 | [
"Biochemists",
"Mass spectrometry",
"Spectrum (physical sciences)",
"Mass spectrometrists"
] |
44,441,313 | https://en.wikipedia.org/wiki/BPDFamily.com | BPDFamily.com is an online support group for the family members of individuals with borderline personality disorder (BPD). The group is one of the first "cyber" support groups to be recognized by the medical providers and receive professional referrals.
BPDFamily.com provides articles and message boards for family members to learn and share their experiences. The articles explain borderline personality disorder in understandable terms, and the discussion groups help to normalize the experiences of family members. The site appeals to family members who care about someone with borderline personality disorder, but are frustrated with the relationship demands and conflict.
The site educates its members on concepts developed by Shari Manning PhD, Margalis Fjelstad PhD, Robert O. Friedel MD, and the NEA-BPD Family Connections Program and reached out to academia for collaborations. The site has an interactive web program that teaches the basic principles of cognitive behavioral therapy.
The website and support group are certified as a reputable health information resource by the Health On the Net Foundation.
Funding has come from benefactors and member donations.
Use by healthcare professionals
BPDFamily.com is a listed reference site of the National Health Service (England), the National Alliance on Mental Illness, the National Education Alliance for Borderline Personality Disorder, and the Personality Disorders Awareness Network.
The group's services and programs are recommended in Primer on Borderline Personality Disorder, Abnormal and Clinical Psychology: An Introductory Textbook, Resources to Improve Emotional Health and Strengthen Relationships, I Hate You--Don't Leave Me: Understanding the Borderline Personality, The Essential Family Guide to Borderline Personality Disorder, Stop Walking on Eggshells, and Discovering Your Inner Child: Transforming Toxic Patterns and Finding Your Joy. The site has been recommended by about.com expert Kristalyn Salters-Pedneault, PhD, Salon advice columnist Cary Tennis, PsychCentral columnist Kate Thieda, and by Randi Kreger at BPDCentral.
The organization has been involved and referenced in clinical research studies conducted by: Columbia University, University of Wollongong (Australia),
California State University, Sacramento, University of Toronto (Canada), University of Nevada, Bowling Green State University, Wright Institute (California), Colorado School of Professional Psychology, Long Island University, Alliant International University (California), Macquarie University (Australia), Middle Tennessee State University, Simon Fraser University (Canada) and Walden University. The organization also supports industry research studies conducted by the Treatment and Research Advancements Association for Personality Disorder (TARA-APD).
In a January 2013 column, Kristalyn Salters-Pedneault at Boston University School of Medicine says that although she highly recommends this group for family members, readers with borderline personality disorder should keep in mind that some people have been hurt by their family member with BPD and are speaking from this perspective.
Traffic
, BPDFamily.com was listed by Alexa Internet as the most visited BPD website in the world, and it ranked 19th among all mental health websites.
References
External links
Mental health support groups
Borderline personality disorder
Suicide prevention
Domestic violence-related organizations
Behavior modification
Relationship counseling
Therapeutic community
Online support groups
Internet forums | BPDFamily.com | [
"Biology"
] | 657 | [
"Behavior modification",
"Behavior",
"Human behavior",
"Behaviorism"
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44,441,329 | https://en.wikipedia.org/wiki/SpaceOps | SpaceOps (also referred to as the International Committee on Technical Interchange for Space Mission Operations and Ground Data Systems) is an international committee organisation formed in 1992 to "promote and maintain an international community of space operations experts".
Currently, thirteen space agencies are members of the organization. SpaceOps also has non-space agency members from academia and industry.
Conferences
SpaceOps Organization has held fifteen biennial conferences hosted by various countries around the world. These international fora have discussed operations principles, methods, cross-support and tools, management and technical interchange.
Future Conferences
SpaceOps 2025 - Montreal, Canada, hosted by: Canadian Space Agency
Most Recent Conferences
Dubai, United Arab Emirates, hosted by: MBRSC, 2023
Daejeon, South Korea, hosted by: KARI, 2016
Marseille, France, CNES, 2018
Capetown, South Africa, SANSA, 2021. It was held virtually and was shifted from the original 2020 date due to COVID-19.
Publications
In 2004, the AIAA Space Operations and Support Technical Committee partnered with the SpaceOps Organization to publish the Journal of Space Operations & Communicator, a peer-reviewed journal dedicated to spaceflight operations and ground support.
Since 2006 most of the conference hosts have decided to publish a post-conference book. These books contain around 30 of the best papers that have been handed in for the conference. The selected papers were all updated, corrected and in many cases extended by the authors following their nomination at the conference.
Awards program
Through its awards program, the SpaceOps Organization recognizes outstanding achievement by individuals and teams in the space operations field. The “International SpaceOps Exceptional Achievement Medal". award recognizes an individual who has distinguished himself or herself in the field of space operations and support.
References
External links
SpaceOps 2025 Website
SpaceOps Website
SpaceOps LinkedIn
Journal of SpaceOperations & Commincator
Space advocacy organizations
Spaceflight | SpaceOps | [
"Astronomy"
] | 383 | [
"Space advocacy organizations",
"Spaceflight",
"Outer space",
"Astronomy organizations"
] |
44,441,512 | https://en.wikipedia.org/wiki/Sporobolomyces%20salmonicolor | Sporobolomyces salmonicolor is a species of fungus in the subdivision Pucciniomycotina. It occurs in both a yeast state and a hyphal state, the latter formerly known as Sporidiobolus salmonicolor. It is generally considered a Biosafety Risk Group 1 fungus; however isolates of S. salmonicolor have been recovered from cerebrospinal fluid, infected skin, a nasal polyp, lymphadenitis and a case of endophthalmitis. It has also been reported in AIDS-related infections. The fungus exists predominantly in the anamorphic (asexual) state as a unicellular, haploid yeast yet this species can sometimes produce a teleomorphic (sexual) state when conjugation of compatible yeast cells occurs. The asexual form consists of a characteristic, pink, ballistosporic yeast. Ballistoconidia are borne from slender extensions of the cell known as sterigmata and are forcibly ejected into the air upon maturity. Levels of airborne yeast cells peak during the night and are abundant in areas of decaying leaves and grains. Three varieties of Sporobolomyces salmonicolor have been described; S. salmonicolor var. albus, S. salmonicolor var. fischerii, and S. salmonicolor var. salmoneus.
Taxonomy
In 1924, Kluyver and van Niel coined the genus Sporobolomyces and classified it under the Basidiomycota. They recognized that the yeast phase produced by Sporobolomyces exhibited the same forcible discharge mechanism as the basidiospores of the Basidiomycota. They therefore hypothesized that the asexual ballistoconidia of Sporobolomyces are homologues with the basidiospores of the Basidiomycota. Their hypothesis however was questioned by many who did not consider the asexual nature of the ballistoconidia as a basidiomycetous trait. Its classification as a basidiomycetous yeast was further demonstrated by Nyland (1949) with the discovery of its teleomorph, placed in the genus Sporidiobolus. The teleomorph presented basidiomycetous traits such as the presence of dikaryotic hyphae with clamp connections and the formation of resting spores known as teliospores. In the past, Sporobolomyces salmonicolor was thought to be conspecific with Sporobolomyces johnsonii; however it is now well established that they are distinct taxa. Sporobolomyces salmonicolor is distinguished from S. johnsonii by the absence in the former of assimilation of maltose, methyl-a-D-glucoside, cellobiose or salicin.
Morphology
Sporobolomyces salmonicolor produces visible, liposoluble carotenoid pigments, resulting in salmon-pink colonies. The colony surface is smooth and has a pasty texture. There is considerable cell and colony morphology when S. salmonicolor is grown in culture. The budding yeast-like cells produced during the asexual stage are ellipsoidal to subcylindrical and 8–25 × 2–5.5 μm. They can occur singly or in pairs. The ballistoconidia are kidney-shaped and can range in size from 6–18 × 2.5–7.0 μm. The characteristic ballistoconidia are borne by extension of the sterigmata which can reach up to 50 μm in length. Both pseudohyphae and true hyphae may also be present.
In its sexual state, Sporobolomyces salmonicolor produces dikaryotic hyphae with clamp connections. At the terminal end of the hyphae, thick-walled teliospores are produced. Teliospores are 9–15 μm in diameter, brown, spherical, and contain lipid-rich globules. Upon germination of the teliospore, basidia with basidiospores are produced. Basidia are transversely septate, two-celled and 4–6 x 20–25 μm in size. Each basidium will generally produce two large basidiospores that are 5–6 × 7–10 μm in size. Prior to the production of the basidium, endospores have also been known to form in the interior of teliospores. This phenomenon is associated with the production of meiospores within the teliospore cytoplasm, ultimately released by rupture of the teliospore wall.
Life cycle
In 1969, Van der Walt and Pitout elucidated the life cycle of S. salmonicolor. They studied a colony of S. salmonicolor grown from a single cell in culture. After several generations, they observed a 2:1 ratio of diploid and haploid cells, respectively. The diploid cells were recovered from thick-walled resting spores known as teliospores. Meiosis was occurring within the teliospore, followed by germination of the teliospore and beginning of the haploid yeast state.
Sporobolomyces salmonicolor is a heterothallic species; two mating types are known. Induction of the sexual stage begins with anastomosis of compatible yeast cells to form dikaryotic hyphae with clamp connections. Hyphae have "simple" septal pores that allow continuity of the cytoplasm between cells. At the terminal end of the hypha, thick-walled, resting spores called teliospores form. These germinate to form a transversely-septate basidium that bears two large basidiospores.
Physiology
The optimum temperature for growth of Sporobolomyces salmonicolor is between , being the highest tolerable temperature. Growth does not occur at . This species does not undergo fermentation. Additionally, Sporobolomyces salmonicolor shows positive urease activity and a positive staining response when stained with diazonium blue B. Diazonium blue B is a technique used to classify asexual yeasts as members of the Zygomycota, Basidiomycota or Ascomycota. The major ubiquinone present is Q-10. The cell wall of S. salmonicolor contains fucose, mannose, glucose and galactose, however xylose is absent. Colonies grow in the presence of glucose, sucrose, maltose, cellobiose, α,α-trehalose, melezitose, D-arabinose, ethanol, glycerol, D-mannitol, D-glucitol, D-gluconate, succinate, nitrate and urease. This species does not assimilate myo-inositol or D-glucuronate, and do not form extracellular starch-like compounds.
Distribution and ecology
Sporobolomyces salmonicolor has a broad geographical distribution. It has been isolated from many areas across the world including Europe, North and South America, Asia, Africa and Antarctica where it is known from a broad spectrum of substrates. It is principally characterized as a phyllosphere fungus and is commonly found in areas of decaying organic material such as leaves and grains as well as ripening grapes. Isolates of this species however have been recovered from freshwater, marine water and clinical specimens. It has also been isolated from agricultural areas and indoor built environments. In agricultural environments, Sporobolomyces salmonicolor can pose a respiratory hazard for agricultural workers. Agricultural workers are subject to increased exposure when they partake in activities involving the handling of grains. Sporobolomyces salmonicolor has additionally been isolated from straw in hay barns or hay lofts. Workers in these settings should consider the proper use of masks to avoid infection. If individuals show atopic symptoms, a change in occupation might be considered. In indoor environments, S. salmonicolor has been associated with severe water and mould damage. Flooded basements and utility rooms are places where S. salmonicolor may be recovered. This fungus will also commonly associate with standing water films, although not very much has been documented on this. It can form a pink water film around stagnant toilet water. The most efficient way to avoid exposure in the home is to eliminate moisture sources and keep bathrooms clean, dry and ventilated.
Pathogenicity
Sporobolomyces salmonicolor is generally interpreted to be a Biosafety Risk Group 1 fungus. It is considered an opportunistic fungal pathogen of immunocompromised individuals and has been reported in AIDS-related infections. Sporobolomyces salmonicolor has been associated with nasal polyps, lymphadenitis, bone marrow involvement in AIDS patients, infected skin, pseudomeningitis and a case of endophthalmitis. S. salmonicolor is also considered a type 1 allergen and has been known to cause asthma, nosocomial allergic alveolitis, and rhinitis.
A 31-year-old woman went to her physician because of decreased vision in her left eye. The left eye showed fibrinous exudates, posterior synechiae and vitritis. After a vitreous sample was sent to the lab for identification, the yeast was identified as Sporobolomyces salmonicolor. The recommended treatment was voriconazole 200 mg, twice a day for two months. Improvement in the left eye was seen within a week. Exposure to mould and yeast within a military hospital in Finland lead to an outbreak of asthma, alveolitis and rhinitis. The building was known to have severe water and mould damage. After performing inhalation provocation tests, four cases of asthma caused by Sporobolomyces salmonicolor were reported. An additional seven workers were diagnosed with rhinitis. All seven individuals with rhinitis acted positively in nasal S. salmonicolor provocation tests. Sporobolomyces salmonicolor was recovered from the cerebrospinal fluid (CSF) of three patients in a hospital, one of whom was a kidney transplant recipient. Heavy growth of S. salmonicolor was recovered from utility rooms on the floors of each patient, and from the hospital rooms of two patients. It was suggested that this particular case was most likely caused by contamination. During the collection process, S. salmonicolor was most likely introduced into the CSF as a contaminant.
Treatment
Clinical infections due to Sporobolomyces salmonicolor are rare and there are currently no standard therapies for infection. Treatment with amphotericin B alone, and amphotericin B followed by either ketoconazole or fluconazole have been successful. In one case of endophthalmitis (mentioned in case report below), treatment with voriconazole was likewise successful. A small number of isolates however demonstrate resistance to fluconazole and micafungin.
Popular culture
The genus Sporobolomyces was the unexpected subject of a poem, The Sporobolomycetologist, with an accompanying musical score, written by the eccentric Canadian mycologist Arthur Henry Reginald Buller.
References
Sporidiobolales
Fungi of Europe
Fungi of North America
Fungi of South America
Fungi of Africa
Fungi of Asia
Fungi of Antarctica
Fungi described in 1894
Fungal pathogens of humans
Fungus species | Sporobolomyces salmonicolor | [
"Biology"
] | 2,419 | [
"Fungi",
"Fungus species"
] |
44,441,540 | https://en.wikipedia.org/wiki/Targeted%20immunization%20strategies | Targeted immunization strategies are approaches designed to increase the immunization level of populations and decrease the chances of epidemic outbreaks. Though often in regards to use in healthcare practices and the administration of vaccines to prevent biological epidemic outbreaks, these strategies refer in general to immunization schemes in complex networks, biological, social or artificial in nature. Identification of at-risk groups and individuals with higher odds of spreading the disease often plays an important role in these strategies, since targeted immunization in high-risk groups is necessary for effective eradication efforts and has a higher return on investment than immunizing larger but lower-risk groups.
Background
The success of vaccines in preventing major outbreaks relies on the mechanism of herd immunity, also known as community immunity, where the immunization of individuals provides protection for not only the individuals, but also the community at large. In cases of biological contagions such as influenza, measles, and chicken pox, immunizing a critical community size can provide protection against the disease for members who cannot be vaccinated themselves (infants, pregnant women, and immunocompromised individuals). Often however these vaccine programmes require the immunization of a large majority of the population to provide herd immunity. A few successful vaccine programmes have led to the eradication of infectious diseases like small pox and rinderpest, and the near eradication of polio, which plagued the world before the second half of the 20th century.
Network-based strategies
More recently researchers have looked at exploiting network connectivity properties to better understand and design immunization strategies to prevent major epidemic outbreaks. Many real networks like the Internet, World Wide Web, and even sexual contact networks have been shown to be scale-free networks and as such exhibit a power-law distribution for the degree distribution. In large networks this results in the vast majority of nodes (individuals in social networks) having few connections or low degree k, while a few "hubs" have many more connections than the average <k>. This wide variability (heterogeneity) in degree offers immunization strategies based on targeting members of the network according to their connectivity rather than random immunization of the network. In epidemic modeling on scale-free networks, targeted immunization schemes can considerably lower the vulnerability of a network to epidemic outbreaks over random immunization schemes. Typically these strategies result in the need for far fewer nodes to be immunized in order to provide the same level of protection to the entire network as in random immunization. In circumstances where vaccines are scarce, efficient immunization strategies become necessary to preventing infectious outbreaks.
Examples
A common approach for targeted immunization studies in scale-free networks focuses on targeting the highest degree nodes for immunization. These nodes are the most highly connected in the network, making them more likely to spread the contagion if infected. Immunizing this segment of the network can drastically reduce the impact of the disease on the network and requires the immunization of far fewer nodes compared to randomly selecting nodes. However, this strategy relies on knowing the global structure of the network, which may not always be practical.
A recent centrality measure, Percolation Centrality, introduced by Piraveenan et al. is particularly useful in identifying nodes for vaccination based on the network topology. Unlike node degree which depends on topology alone, however, percolation centrality takes into account the topological importance of a node as well as its distance from infected nodes in deciding its overall importance. Piraveenan et al. has shown that percolation centrality-based vaccination is particularly effective when the proportion of people already infected is on the same order of magnitude as the number of people who could be vaccinated before the disease spreads much further. If infection spread is at its infancy, then ring-vaccination surrounding the source of infection is most effective, whereas if the proportion of people already infected is much higher than the number of people that could be vaccinated quickly, then vaccination will only help those who are vaccinated and herd immunity cannot be achieved. Percolation centrality-based vaccination is most effective in the critical scenario where the infection has already spread too far to be completely surrounded by ring-vaccination, yet not spread wide enough so that it cannot be contained by strategic vaccination. Nevertheless, Percolation Centrality also needs full network topology to be computed, and thus is more useful in higher levels of abstraction (for example, networks of townships rather than social networks of individuals), where the corresponding network topology can more readily be obtained.
Increasing immunization coverage
Millions of children worldwide do not receive all of the routine vaccinations as per their national schedule. As immunization is a powerful public health strategy for improving child survival, it is important to determine what strategies work best to increase coverage. A Cochrane review assessed the effectiveness of intervention strategies to boost and sustain high childhood immunization coverage in low- and middle-income countries. Forty-one trials were included but most of the evidence was of low quality. Providing parents and other community members with information on immunization, health education at facilities in combination with redesigned immunization reminder cards, regular immunization outreach with and without household incentives, home visits, and integration of immunization with other services may improve childhood immunization coverage in low-and middle-income countries.
See also
Influenza vaccine
Immunization
Vaccine-preventable diseases
Smallpox eradication
Poliomyelitis eradication
Infectious diseases
ILOVEYOU (computer worm epidemic in 2000)
Epidemiology
Epidemic model
Network Science
Critical community size
Scale-free network
Complex network
Percolation theory
Pandemic
References
Vaccination
Social networks
Epidemiology
Epidemics
Preventive medicine
Pandemics | Targeted immunization strategies | [
"Biology",
"Environmental_science"
] | 1,192 | [
"Epidemiology",
"Vaccination",
"Environmental social science"
] |
44,442,017 | https://en.wikipedia.org/wiki/Sleep%20and%20weight | Sleep and weight is the association between the amount of sleep an individual obtains and the weight of that individual.
Numerous studies have demonstrated an association between sleep disturbances and weight gain, and more specifically, that sleep deprivation is related to overweight. Furthermore, body weight also influences the quality of sleep and the occurrence of sleep disorders like obstructive sleep apnea. Oversleeping may also contribute to weight gain.
Additionally, there is a decrease in sleep duration and quality among most populations due to modern lifestyles which include an increased time spent looking at artificial lights from screens. The availability of night-time use of electronic devices and communication devices are associated with shorter sleep duration and increased body weight in children.
Relationship between stress, sleep and weight
The biological reaction to a stressor is the activation of the HPA-axis. In a stressful environment the body will release multiple hormones including cortisol. Over a long duration high cortisol concentrations can have negative effects on the immune system, attention and memory and can increase the risk of psychological disorders, such as depression. Also, too much stress can have an impact on sleep and is a risk factor of insomnia.
Stress can have an effect on sleep patterns, food intake and consequently weight gain. Stress has been found to be associated with increased emotional reward of palatable foods, which in turn can also lead to obesity. There seems to be only a one-sided relationship between cortisol levels and sleep deprivation. High cortisol levels due to high stress can lead to decreased sleep duration. However, 24-hour sleep deprivation does not seem to lead to changes in cortisol levels in healthy adults.
However, it is believed that chronic sleep deprivation has a negative effect on the neuroendocrine system and seems to change the ways in which people deal with challenges. The first changes appear to be on emotional perception, but might also change the fundamental properties of the neuroendocrine stress axis in the long run.
Lack of sleep related to weight gain
Lack of sleep has been strongly associated with weight gain in a variety of studies across all ages, though research suggests children and adolescents are particularly vulnerable. However, the exact mechanisms in which sleep deprivation leads to weight gain are diverse. Sleep deprivation is believed to have an influence on body weight in several different aspects: Sleep deprivation influences the brain's response to high-calorie food by making it more attractive, which leads to high-energy food choices, affects the production of the hormones ghreline and Leptin.
Not only sleep reduction, also disruption of the circadian clock can have a negative impact on sleep architecture and metabolism, as shown in mouse models. In adolescence late bedtimes are related to a higher risk of getting obese and great bedtime shifts between weekdays and weekend were associated with greater severity of overweight and longer screen time use. In general, sleeping less than 7 hours per night increases the risk to be obese.
Another plausible explanation is that fatigue because of limited sleep reduces physical activity and thus energy expenditure, which predisposes weight gain. Others show a non-reciprocal relationship where fatness predicts less physical activity and also sleep duration predict fatness, but an association was not found in a model which includes all three factors.
Sleep deprivation is believed to influence the brain's response to high-calorie food, making it more attractive, while also affecting the production of hormones that control appetite. Matthew P Walker, a psychology and neuroscience professor at UC Berkeley, published a study during which the participants were deprived of sleep for one night. The New York Times summarized his study as such, "On days when the subjects had not had proper sleep, fattening foods like potato chips and sweets stimulated stronger responses in a part of the brain that helps govern the motivation to eat. But at the same time, the subjects experienced a sharp reduction in activity in the frontal cortex, a higher level part of the brain where consequences are weighed and rational decisions are made." A brain that has been deprived of sleep for one night is more likely to respond more intensely to junk food but also has the decreased ability to curb that desire. These results were consistent even as the subjects were given extra calories to compensate for the amount of energy expended during those extra hours that the subjects stayed awake, which indicates that one's craving for junk food is not a response to offset an energy deficit. Walker further speculates that one of the biological basis for this reaction could the buildup of adenosine, a metabolic byproduct that may degrade communication between networks in the brain. Adenosine is cleared from the brain during sleep.
Previous research by the University of Chicago had also associated short sleep with an increase in calorie consumption from snacks, albeit with no change in overall calorie intake, hormone levels or energy expenditure across the different sleep schedules tested. A 2014 review of studies on the link between sleep debt and obesity also reported no association between short sleep duration and total energy expenditure.
A study of Gonnissen et al. (2012) showed that the desire-to-eat ratings were higher after a night of fragmented sleep in comparison to a normal night of sleep. This could be one explanation why people eat more when they are sleep deprived. Another study with adolescents found greater neural activation in brain regions associated with inhibition in response to food cues after sleep restriction and also found neural activation was consistent with greater reward processing associated with food cues after sleep restriction. These findings did not differ in groups with normal weight or overweight/obese.
Sleep restriction in normal-weight subjects also showed an increase in activity of reward and food-sensitive areas of the brain when viewing unhealthy food, compared with viewing healthy food. This study shows a link between restricted sleep and susceptibility to food stimuli, which might increase the risk of overeating.
Another explanation of the relationship stems from the balance between two hormones, leptin and ghrelin, which act on the nuclei of the hypothalamus to monitor energy and food intake. Leptin primarily inhibits appetite while ghrelin, which is the released by the stomach, works to stimulate appetite. Sleep deprivation has been associated with increased levels of ghrelin and decreased levels of leptin in multiple studies. In addition to the hormonal variation, other research has also associated shortened sleep durations with a proportional increase in subjects' BMIs.
Metabolism
Sleep is an important modulator of neuroendocrine function and glucose metabolism and sleep loss has been shown to result in metabolic and endocrine alterations, including decreased glucose tolerance, decreased insulin sensitivity, increased evening concentrations of cortisol, increased levels of ghrelin, decreased levels of leptin, and increased hunger and appetite/ There is evidence that the circadian rhythm is tightly associated with sleep and metabolism. Disruption of this coordination can lead to the metabolic syndrome or type 2 diabetes. Recent epidemiological and laboratory evidence confirm previous findings of an association between sleep loss and increased risk of obesity.
Metabolism involves two biochemical processes that occur in living organisms. The first is anabolism, which refers to the buildup of molecules. The second is catabolism, the breakdown of molecules. These two processes work to regulate the amount of energy the body uses to maintain itself. During non-REM sleep, metabolic rate and brain temperature are lowered to deal with damages that may have occurred during time of wakefulness.
Sleep is important in regulating metabolism. Mammalian sleep can be sub-divided into two distinct phases - REM (rapid eye movement) and non-REM (NREM) sleep. In humans, NREM sleep has four stages, where the third and fourth stages are considered slow-wave sleep (SWS). SWS is considered deep sleep, when metabolism is least active.
In normal metabolic function, the pancreas releases insulin after blood glucose levels raise. Insulin signals muscle and fat cells to absorb glucose from food. As a result, blood glucose levels return to normal.
Sleep loss can affect the basic metabolic functions and glucose homeostasis. Reduction of sleep from eight hours to four hours produces changes in glucose tolerance and endocrine function. Researchers from the University of Chicago Medical Center followed 11 healthy young men for 16 consecutive nights. The first 3 nights, the young men slept for the normal 8 hours. The next 6 nights, they slept for 4 hours. The next 7 nights, they spent 12 hours in bed. They all had the same diet. They found that there were changes in glucose metabolism that resemble that of type 2 diabetes patients. When the participants were tested after sleep deprivation, they took 40% longer than normal to regulate blood sugar levels after a high-carbohydrate meals. The secretion of insulin and the body's response to insulin decrease by 30%. Sleep deprivation also alters the productions of hormones, lowering the secretion of thyroid stimulating hormone and increasing blood levels of cortisol.
Sleeping more to promote weight loss
A regular sleep schedule can contribute to weight loss. While sleeping more than an average of 6.5 hours per night may have beneficial effects on weight, sleeping over 8.5 hours per night has been shown to contribute negatively to weight. Getting adequate sleep may also reduce snacking that occurs throughout the course of the day due to feeling lethargic.
Effect of oversleeping
There have been many connections made between oversleeping and certain disorders. Many of these have been made without any identifiable reason for correlation, and are mainly observational. WebMD reports that sleep apnea may cause oversleeping because of disruptions in the normal sleep cycle, that individuals who sleep more may be more prone to headaches because of neurotransmitters imbalances, back pain can increase with oversleeping because a certain level of physical activity is not being maintained, and that oversleeping may be correlated with depression and higher death rates.
However, these connections have not been subject to rigorous examination. On the other hand, there have been studies that have looked into the potential physical side effects of oversleeping on weight and weight-related conditions. A study of the life habits of 276 subjects over a 6-year period and found that about 20% of those with long (9+ hours) of sleeping time developed type 2 diabetes or impaired glucose tolerance as compared to 7% in those that slept an average amount of time.
Long-duration sleepers (9–10 hours) were 25% more likely to experience a 5-kg weight gain, and a 21% increase in risk of obesity, when adjusted for age, sex, and baseline BMI, as compared to average duration sleepers (7–8 hours). Even after adjusting for energy expenditure and physical activity levels (among other covariates), these relationships remained significant. A U-shaped relationship between hours of sleep and type 2 diabetes, coronary heart disease and weight is observed, but the metabolic mechanisms affected by long sleep duration are less clear than with sleep restriction and remain somewhat speculative.
A Nurses' Health Study analyzed a group of about 72,000 US women who did not report having coronary heart disease at the onset of the study, and assessed the relationship between their reported sleep durations and incidence of a CHD event over a period of 10 years. At the conclusion of the study, the data indicated that women who slept a longer duration (9–11 hours) were 38% more likely to have CHD than women who slept 8 hours. However, the researchers had no plausible explanation for a cause-and-effect relationship.
Obesity related sleep disorders
Obese subjects are vulnerable for sleep-related breathing disorders, such as sleep apnea. The mechanisms of body weight having an influence on sleep-related breathing disorders are various and include possible alterations in upper airway structure, alterations in upper airway function, alterations in the balance between ventilatory drive and load. Some studies did find a positive effect of changing in lifestyle like weight loss and regular exercise in subjects with minimal obstructive sleep apnea, the evidence of weight loss being an effective treatment for obstructive sleep apnea has limited empirical support In his review, Veasey et al. reviewed 39 papers, the majority of them evaluating the effects of weight loss, achieved by bariatric surgery on symptoms of obstructive sleep apnea. They found associations between weight loss and reduction of symptom frequency. However, most studies did not have control groups, a randomized design and high alpha and beta error. Hence, Foster et al. showed in their randomized study that weight loss has a significant improvement of symptoms in obese obstructive sleep apnea patients with type 2 diabetes.
Sleep apnea
Sleep apnea is a sleep disorder which causes an individual to have short pauses in breathing or very shallow breaths while sleeping. These pauses in breathing can often cause the individual to wake up, snore, choke, or just generally disrupt their sleep. As a result, affected people do not get quality sleep during the night and are tired during the daytime. Sleep apnea is very difficult to diagnose because doctors can't exactly tell if a person has sleep apnea in a regular routine visit. Additionally the patient himself may not even realize he has sleep apnea because it occurs during sleep, so a partner or roommate is usually the first to notice symptoms.
There are two types of sleep apnea, obstructive and central. Obstructive sleep apnea is more common among overweight patients, and occurs when the airway is fully or partially blocked at times during sleep. Any air that does sneak by the blocked passage can cause loud snoring. The second type of sleep apnea, central sleep apnea, is much more rare and has to do with the part of the brain that regulates breathing. The signal from the brain to the lungs is disrupted, resulting in pauses in breathing.
Treating obstructive sleep apnea is much easier than central sleep apnea, and the treatment plan may include things such as lifestyle changes, mouthpieces, surgery, and breathing devices
Since overweight is one of the most important risk factors for obstructive sleep apnea, weight loss interventions combined with active lifestyle counseling showed to be beneficial. A randomized control study showed reduced symptom frequency in patients who participated in a weight loss programm, combined with active lifestyle counselling. This intervention seemed to be beneficial for patients with mild obrustrive sleep apnea. The positive effects were maintained at 1-year follow-up
Sleep deprivation and type 2 diabetes
Baseline levels of insulin do not signal muscle and fat cells to absorb glucose. When glucose levels are elevated, the pancreas responds by releasing insulin. Blood sugar will then rapidly drop. This can progress to type 2 diabetes.
Sleep loss can affect the basic metabolic functions of storing carbohydrates and regulating hormones. Reduction of sleep from eight hours to four hours produces changes in glucose tolerance and endocrine function. Researchers from the University of Chicago Medical Center followed 11 healthy young men for 16 consecutive nights. The first 3 nights, the young men slept for the normal 8 hours. The next 6 nights, they slept for 4 hours. The next 7 nights, they spent 12 hours in bed. They all had the same diet. They found that there were changes in glucose metabolism that resemble that of type 2 diabetes patients. When the participants were tested after sleep deprivation, they took 40% longer than normal to regulate blood sugar levels after a high-carbohydrate meals. The secretion of insulin and the body's response to insulin decrease by 30%. Sleep deprivation also alters the productions of hormones, lowering the secretion of thyroid stimulating hormone and increasing blood levels of cortisol.
It has also been shown that when slow-wave sleep was suppressed for three nights, young healthy subjects were 25% less sensitive to insulin. They needed more insulin to get rid of the same amount of glucose. If the body does not release more insulin to compensate, the blood-glucose levels will increase. This resembles impaired glucose tolerance, which can result in type 2 diabetes.
Sleep in the media
As obesity has become an issue of nationwide focus, media sources have begun to explore and report on the link between sleep and weight. The coverage spans from articles in Women's Health Magazine on "6 Ways Sleep Can Help you Lose Weight," to NPR's story on the research linking a lack of sleep to obesity, to Harvard School of Public Health's discussion of sleep as an "obesity prevention source" on their site.
Although it is often presented like this in the media, sleep is not a universal solution to obesity, direct evidence for losing weight because of sleeping more does not exist. Rather there are several aspects of sleep deprivation that might contribute to weight gain. Horne (2008) claims that especially for short sleepers, who normally sleep 5 hours per night, to sleep more will not be a working strategy to lose weight, since habitually short sleep develops over many years.
References
Sleep | Sleep and weight | [
"Biology"
] | 3,477 | [
"Behavior",
"Sleep"
] |
44,442,470 | https://en.wikipedia.org/wiki/Shoolery%27s%20rule | Shoolery's rule, which is named after James Nelson Shoolery, is a good approximation of the chemical shift δ of methylene groups in proton nuclear magnetic resonance. We can calculate shift of the CH2 protons in a A–CH2–B structure using the formula
where 0.23 ppm is the chemical shift of methane and the empirical adjustments are based on the identities of the A and B groups:
Shoolery's rule is a particular instance of a general class of rules of the form
,
with two substituents on methylene resulting in two parameters and .
References
External links
Organic Spectroscopy: Principles and Applications, page 206
Nuclear magnetic resonance | Shoolery's rule | [
"Physics",
"Chemistry"
] | 138 | [
"Nuclear chemistry stubs",
"Nuclear magnetic resonance",
"Nuclear magnetic resonance stubs",
"Nuclear physics"
] |
44,442,903 | https://en.wikipedia.org/wiki/Identity%20interrogation | Identity interrogation is a method of authentication or identity proofing that involves posing one or more knowledge-based authentication questions to an individual. Identity interrogation questions such as "What is your mother’s maiden name?" or "What are the last four digits of your social security number?" It is a method businesses use to prevent identity theft or impersonation of customers.
Identity interrogation is primarily employed during remote, not in-person interactions, such as with a teller at a bank. Many interactions that require user authentication over the Internet or the telephone employ Identity interrogation as a substitute for stronger authentication methods such as physical ownership authentication (i.e. presenting a driver's license or a bankcard), or biometrics (i.e. fingerprint or facial recognition) available mainly during in-person interactions. Identity interrogation is used to assist with risk management, account security, and legal and regulatory compliance during remote interactions. In addition, the technique was developed to assist in the prevention of identity fraud, or the illegal use of another person's identity to commit fraud or other criminal activities.
Identity interrogation methods are most commonly used by governments, organizations and companies such as banks or financial intermediaries, credit card companies, internet providers, telecommunications companies, insurance providers and others.
See also
TRUSTID
Notes
Computer network security
Identity management | Identity interrogation | [
"Engineering"
] | 269 | [
"Cybersecurity engineering",
"Computer networks engineering",
"Computer network security"
] |
44,443,296 | https://en.wikipedia.org/wiki/2-Octyne | 2-Octyne, also known as methylpentylethyne and oct-2-yne, is a type of alkyne with a triple bond at its second carbon (the '2-' indicates the location of the triple bond in the chain). Its formula is C8H14. Its density at 25 °C and otherwise stable conditions is 0.759 g/ml. The boiling point is 137 °C. The average molar mass is 110.20 g/mol.
It is formed by isomerization of 1-octyne catalyzed by a YbII complex.
References
Alkynes | 2-Octyne | [
"Chemistry"
] | 129 | [
"Organic compounds",
"Alkynes"
] |
44,443,349 | https://en.wikipedia.org/wiki/Americium%28IV%29%20fluoride | Americium(IV) fluoride is the inorganic compound with the formula AmF4. It is a tan solid. In terms of its structure, solid AmF4 features 8-coordinate Am centers interconnected by doubly bridging fluoride ligands.
References
Americium compounds
Fluorides
Actinide halides | Americium(IV) fluoride | [
"Chemistry"
] | 72 | [
"Inorganic compounds",
"Fluorides",
"Inorganic compound stubs",
"Salts"
] |
44,443,365 | https://en.wikipedia.org/wiki/Americium%28III%29%20fluoride | Americium(III) fluoride or americium trifluoride is the chemical compound composed of americium and fluorine with the formula AmF3. It is a water soluble, pink salt.
References
Americium compounds
Fluorides
Actinide halides | Americium(III) fluoride | [
"Chemistry"
] | 61 | [
"Inorganic compounds",
"Fluorides",
"Inorganic compound stubs",
"Salts"
] |
44,443,368 | https://en.wikipedia.org/wiki/Americium%28III%29%20bromide | Americium(III) bromide or americium tribromide is the chemical compound composed of americium and bromine with the formula AmBr3, with americium in a +3 oxidation state. The compound is a crystalline solid.
References
Americium compounds
Bromides
Actinide halides | Americium(III) bromide | [
"Chemistry"
] | 67 | [
"Bromides",
"Salts",
"Inorganic compounds",
"Inorganic compound stubs"
] |
44,443,379 | https://en.wikipedia.org/wiki/Americium%28III%29%20iodide | Americium(III) iodide or americium triiodide is the chemical compound, a salt composed of americium and iodine with the formula AmI3.
Preparation
Americium(III) iodide can be prepared by reacting americium(III) chloride with ammonium iodide:
Properties
Americium(III) iodide takes the form of yellow crystals. The crystal form is orthorhombic. It melts around 960 °C. The density is 6.9 g/cm3. The compound consists of Am3+ and I− ions. It crystallizes in the trigonal crystal system in the space group R (space group no. 148) with the lattice parameters a = 742 pm and c = 2055 pm and six formula units per unit cell. Its crystal structure is isotypic with bismuth(III) iodide.
References
Americium compounds
Iodides
Actinide halides | Americium(III) iodide | [
"Chemistry"
] | 200 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
44,443,385 | https://en.wikipedia.org/wiki/Americium%28II%29%20bromide | Americium(II) bromide or americium dibromide is the chemical compound, a salt composed of an americium cation in the +2 oxidation state and 2 bromide ions in each formula unit, with the formula AmBr2.
References
Americium compounds
Bromides
Actinide halides | Americium(II) bromide | [
"Chemistry"
] | 68 | [
"Bromides",
"Inorganic compounds",
"Inorganic compound stubs",
"Salts"
] |
44,443,391 | https://en.wikipedia.org/wiki/Americium%28II%29%20iodide | Americium(II) iodide is the inorganic compound with the formula AmI2. It is a black solid which crystallizes in the same motif as strontium bromide.
References
Americium compounds
Iodides
Actinide halides | Americium(II) iodide | [
"Chemistry"
] | 54 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
44,444,467 | https://en.wikipedia.org/wiki/UniDIMM | UniDIMM (short for Universal DIMM) is a specification for dual in-line memory modules (DIMMs), which are printed circuit boards (PCBs) designed to carry dynamic random-access memory (DRAM) chips. UniDIMMs can be populated with either DDR3 or DDR4 chips, with no support for any additional memory control logic; as a result, the computer's memory controller must support both DDR3 and DDR4 memory standards. The UniDIMM specification was created by Intel for its Skylake microarchitecture, whose integrated memory controller (IMC) supports both DDR3 (more specifically, the DDR3L low-voltage variant) and DDR4 memory technologies.
UniDIMM is a SO-DIMM form factor available in two dimensions: for the standard UniDIMM version (the same size as DDR4 SO-DIMMs), and for the low-profile version. UniDIMMs have a 260-pin edge connector, which has the same pin count as the one on DDR4 SO-DIMMs, with the keying notch in a position that prevents incompatible installation by making UniDIMMs physically incompatible with standard DDR3 and DDR4 SO-DIMM sockets. Because of the lower operating voltage of DDR4 chips (1.2 V) compared with the operating voltage of DDR3 chips (1.5 V for regular DDR3 and 1.35 V for low-voltage DDR3L), UniDIMMs are designed to contain additional built-in voltage regulation circuitry.
The UniDIMM specification was created to ease the market transition from DDR3 to DDR4 SDRAM. In previous RAM standard transitions, as it was the case when DDR2 was phased out in favor of DDR3, having an emerging RAM standard as a new product line created a "chicken-and-egg" problem because its manufacturing is initially more expensive, yields low demand, and results in low production rates. The DDR2 to DDR3 transition issues were sometimes handled with specific motherboards that provided separate slots for DDR2 and DDR3 modules, out of which only one kind could be used. By its design, the UniDIMM specification allows either DDR3 or DDR4 memory to be used in the same memory module slots, resulting in no wasted motherboard space that would otherwise be occupied by unused slots.
, UniDIMM is not standardized by JEDEC, having Kingston and Micron as its main supporters. Despite the availability of UniDIMM specification and announced manufacturer support, there are no commercial UniDIMM products available and no release dates have been set by the manufacturers. As DDR3 has become more irrelevant after years of DDR4 availability, it is looking increasingly unlikely that manufacturers will ever implement UniDIMM.
See also
Centaur (computing) POWER8's external memory controller that makes POWER8 independent of the actual memory technology
Memory geometry describes the logical configuration of RAM modules, including channels, ranks and banks
References
External links
DDR4 white paper, Corsair Components, archived from the original on October 10, 2014
Computer memory form factor
Vaporware | UniDIMM | [
"Technology"
] | 659 | [
"Computer industry",
"Vaporware"
] |
44,445,196 | https://en.wikipedia.org/wiki/Circumpolar%20distribution | A circumpolar distribution is any range of a taxon that occurs over a wide range of longitudes but only at high latitudes; such a range therefore extends all the way around either the North Pole or the South Pole. Taxa that are also found in isolated high-mountain environments further from the poles are said to have arctic–alpine distributions.
Animals with circumpolar distributions include the reindeer, polar bear, Arctic fox, snowy owl, snow bunting, king eider, brent goose and long-tailed skua in the north, and the Weddell seal and Adélie penguin in the south.
Plants with northern circumpolar distributions include Eutrema edwardsii (syn. Draba laevigata), Saxifraga oppositifolia, Persicaria vivipara and Honckenya peploides.
References
Biogeography
Polar regions of the Earth | Circumpolar distribution | [
"Biology"
] | 183 | [
"Biogeography"
] |
44,446,557 | https://en.wikipedia.org/wiki/C10H8O2 | {{DISPLAYTITLE:C10H8O2}}
The molecular formula C10H8O2 may refer to:
1,5-Dihydroxynaphthalene, one of several isomers of dihydroxynaphthalene
Methylcoumarin, isomer in which a methyl group substitutes for a hydrogen atom in coumarin | C10H8O2 | [
"Chemistry"
] | 77 | [
"Isomerism",
"Set index articles on molecular formulas"
] |
44,447,884 | https://en.wikipedia.org/wiki/Inbreeding%20avoidance | Inbreeding avoidance, or the inbreeding avoidance hypothesis, is a concept in evolutionary biology that refers to the prevention of the deleterious effects of inbreeding. Animals only rarely exhibit inbreeding avoidance. The inbreeding avoidance hypothesis posits that certain mechanisms develop within a species, or within a given population of a species, as a result of assortative mating and natural and sexual selection, in order to prevent breeding among related individuals. Although inbreeding may impose certain evolutionary costs, inbreeding avoidance, which limits the number of potential mates for a given individual, can inflict opportunity costs. Therefore, a balance exists between inbreeding and inbreeding avoidance. This balance determines whether inbreeding mechanisms develop and the specific nature of such mechanisms.
A 2007 study showed that inbred mice had significantly reduced survival when they were reintroduced into a natural habitat.
Inbreeding can result in inbreeding depression, which is the reduction of fitness of a given population due to inbreeding. Inbreeding depression occurs via appearance of disadvantageous traits due to the pairing of deleterious recessive alleles in a mating pair's progeny. When two related individuals mate, the probability of deleterious recessive alleles pairing in the resulting offspring is higher as compared to when non-related individuals mate because of increased homozygosity. However, inbreeding also gives opportunity for genetic purging of deleterious alleles that otherwise would continue to exist in population and could potentially increase in frequency over time. Another possible negative effect of inbreeding is weakened immune system due to less diverse immunity alleles as a result of outbreeding depression.
A review of the genetics of inbreeding depression in wild animal and plant populations, as well as in humans, led to the conclusion that inbreeding depression and its opposite, heterosis (hybrid vigor), are predominantly caused by the presence of recessive deleterious alleles in populations. Inbreeding, including self-fertilization in plants and automictic parthenogenesis (thelytoky) in hymenoptera, tends to lead to the harmful expression of deleterious recessive alleles (inbreeding depression). Cross-fertilization between unrelated individuals ordinarily leads to the masking of deleterious recessive alleles in progeny.
Many studies have demonstrated that homozygous individuals are often disadvantaged with respect to heterozygous individuals. For example, a study conducted on a population of South African cheetahs demonstrated that the lack of genetic variability among individuals in the population has resulted in negative consequences for individuals, such as a greater rate of juvenile mortality and spermatozoal abnormalities. When heterozygotes possess a fitness advantage relative to a homozygote, a population with a large number of homozygotes will have a relatively reduced fitness, thus leading to inbreeding depression. Through these described mechanisms, the effects of inbreeding depression are often severe enough to cause the evolution of inbreeding avoidance mechanisms.
Mechanisms
Inbreeding avoidance mechanisms have evolved in response to selection against inbred offspring. Inbreeding avoidance occurs in nature by at least four mechanisms: kin recognition, dispersal, extra-pair/extra-group copulations, and delayed maturation/reproductive suppression. These mechanisms are not mutually exclusive and more than one can occur in a population at a given time.
Kin recognition
Kin recognition is the mechanism by which individuals identify and avoid mating with closely related conspecifics. There have been numerous documented examples of instances in which individuals are shown to find closely related conspecifics unattractive. In one set of studies, researchers formed artificial relative and non-relative mate-pairs (artificial meaning they preferentially paired individuals to mate for the purposes of the experiments) and compared the reproductive results of the two groups. In these studies, paired relatives demonstrated reduced reproduction and higher mating reluctance when compared with non-relatives. For example, in a study by Simmons in field crickets, female crickets exhibited greater mating latency for paired siblings and half-siblings than with non-siblings. In another set of studies, researchers allowed individuals to choose their mates from conspecifics that lie on a spectrum of relatedness. In this set, individuals were more likely to choose non-related over related conspecifics. For example, in a study by Krackow et al., male wild house mice were set up in an arena with four separate openings leading to cages with bedding from conspecifics. The conspecifics exhibited a range of relatedness to the test subjects, and the males significantly preferred the bedding of non-siblings to the bedding of related females.
Studies have shown that kin recognition is more developed in species in which dispersal patterns facilitate frequent adult kin encounters.
There is a significant amount of variation in the mechanisms used for kin recognition. These mechanisms include recognition based on association or familiarity, an individual's own phenotypic cues, chemical cues, and the MHC genes. In association/familiarity mechanisms, individuals learn the phenotypic profiles of their kin and use this template for kin recognition. Many species accomplish this by becoming "familiar" with their siblings, litter mates, or nestmates. These species rely on offspring being reared in close proximity to achieve kin recognition. This is called the Westermarck effect. For example, Holmes and Sherman conducted a comparative study in Arctic ground squirrels and Belding's ground squirrels. They manipulated the reared groups to include both siblings and cross-fostered nestmates and found that in both species the individuals were equally aggressive toward their nestmates, regardless of kinship. In certain species where social groups are highly stable, relatedness and association between infants and other individuals are usually highly correlated. Therefore, degree of association can be used as a meter for kin recognition.
Individuals can also use their own characteristics or phenotype as a template in kin recognition. For example, in one study, Mateo and Johnston had golden hamsters reared with only non-kin then later had them differentiate between odors of related and non-related individuals without any postnatal encounters with kin. The hamsters were able to discriminate between the odors, demonstrating the use of their own phenotype for the purpose of kin recognition. This study also provides an example of a species utilizing chemical cues for kin recognition.
The major histocompatibility complex genes, or MHC genes, have been implicated in kin recognition. One idea is that the MHC genes code for a specific pheromone profile for each individual, which are used to discriminate between kin and non-kin conspecifics. Several studies have demonstrated the involvement of the MHC genes in kin recognition. For example, Manning et al. conducted a study in house mice that looked at the species's behavior of communal nesting, or nursing one's own pups as well as the pups of other individuals. As Manning et al. state, kin selection theory predicts that the house mice will selectively nurse the pups of their relatives in order to maximize inclusive fitness. Manning et al. demonstrate that the house mice utilize the MHC genes in the process of discriminating between kin by preferring individuals who share the same allelic forms the MHC genes.
Human kin recognition
The possible use of olfaction-biased mechanisms in human kin recognition and inbreeding avoidance was examined in three different types of study. The results indicated that olfaction may help mediate the development during childhood of incest avoidance (the Westermarck effect).
Post-copulatory inbreeding avoidance in mice
Experiments using in vitro fertilization in the mouse, provided evidence of sperm selection at the gametic level. When sperm of sibling and non-sibling males were mixed, a fertilization bias towards the sperm of the non-sibling males was observed. The results were interpreted as egg-driven sperm selection against related sperm.
Inbreeding avoidance in plants
Experiments were performed with the dioecious plant Silene latifolia to test whether post-pollination selection favors less related pollen donors and reduces inbreeding. The results showed that in S. latifolia, and presumably in other plant systems with inbreeding depression, pollen or embryo selection after multiple-donor pollination may reduce inbreeding.
Dispersal
Some species will adopt dispersal as a way to separate close relatives and prevent inbreeding. The initial dispersal route species may take is known as natal dispersal, whereby individuals move away from the area of birth. Subsequently, species may then resort to breeding dispersal, whereby individuals move from one non-natal group to another. Nelson-Flower et al. (2012) conducted a study on southern pied babblers and found that individuals may travel farther distances from natal groups than from non-natal groups. This may be attributed to the possibility of encountering kin within local ranges when dispersing. The extent to which an individual in a particular species will disperse depends on whether the benefits of dispersing can outweigh both the costs of inbreeding and the costs of dispersal. Long‐distance movements can bear mortality risks and energetic costs.
Sex-biased dispersal
In many cases of dispersal, one sex shows a greater tendency to disperse from their natal area than the opposite sex. The extent of bias for a particular sex is dependent on numerous factors which include, but are not limited to: mating system, social organization, inbreeding and dispersal costs, and physiological factors. When the costs and benefits of dispersal are symmetric for both males and females, then no sex-biased dispersal is expected to be observed in species.
Female dispersal
Birds tend to adopt monogamous mating systems in which the males remain in their natal groups to defend familiar territories with high resource quality. Females generally have high energy expenditure when producing offspring, therefore inbreeding is costly for the females in terms of offspring survival and reproductive success. Females will then benefit more by dispersing and choosing amongst these territorial males. In addition, according to the Oedipus hypothesis, daughters of female birds can cheat their mothers through brood parasitism, therefore females will evict the females from the nest, forcing their daughters to disperse. Female dispersal is not seen only in birds; males may remain philopatric in mammals when the average adult male residency in a breeding group exceeds the average age for female maturation and conception. For example, in a community of chimpanzees in Gombe National Park, males tend to remain in their natal community for the duration of their lives, while females typically move to other communities as soon as they reach maturity.
Male dispersal
Male dispersal is more common in mammals with cooperative breeding and polygynous systems. Australian marsupial juvenile males have a greater tendency to disperse from their natal groups, while the females remain philopatric. In Antechinus, this is due to the fact that males die immediately after mating; therefore when they disperse to mate, they often meet with female natal groups with zero males present. Furthermore, the Oedipus hypothesis also states that fathers in polygynous systems will evict sons with the potential to cuckold them. Polygynous mating systems also influence intrasexual competition between males, where in cases where males can guard multiple females and exert their dominance, subordinate males are often forced to disperse to other non-natal groups.
When species adopt alternative inbreeding avoidance mechanisms, they can indirectly influence whether a species will disperse. Their choice for non-natal group males then selects for male dispersal.
Delayed maturation
The delayed sexual maturation of offspring in the presence of parents is another mechanism by which individuals avoid inbreeding. Delayed maturation scenarios can involve the removal of the original, opposite-sex parent, as is the case in female lions that exhibit estrus earlier following the replacement of their fathers with new males. Another form of delayed maturation involves parental presence that inhibits reproductive activity, such as in mature marmosets offspring that are reproductively suppressed in the presence of opposite sex parents and siblings in their social groups.
Reproductive suppression occurs when sexually mature individuals in a group are prevented from reproducing due to behavioral or chemical stimuli from other group members that suppress breeding behavior. Social cues from the surrounding environment often dictate when reproductive activity is suppressed and involves interactions between same-sex adults. If the current conditions for reproduction are unfavorable, such as when presented with only inbreeding as a means to reproduce, individuals may increase their lifetime reproductive success by timing their reproductive attempts to occur during more favorable conditions. This can be achieved by individuals suppressing their reproductive activity in poor reproduction conditions.
Inbreeding avoidance between philopatric offspring and their parents/siblings severely restricts breeding opportunities of subordinates living in their social groups. A study by O'Riain et al. (2000) examined meerkats social groups and factors affecting reproductive suppression in subordinate females. They found that in family groups, the absence of a dominant individual of either sex led to reproductive quiescence. Reproductive activity only resumed upon another sexually mature female obtaining dominance, and immigration of an unrelated male. Reproduction required both the presence of an unrelated opposite-sex partner, which acted as appropriate stimulus on reproductively suppressed subordinates that were quiescent in the presence of the original dominant individual.
Extra-pair copulations
In various species, females benefit by mating with multiple males, thus producing more offspring of higher genetic diversity and potentially quality. Females that are pair bonded to a male of poor genetic quality, as can be the case in inbreeding, are more likely to engage in extra-pair copulations in order to improve their reproductive success and the survivability of their offspring. This improved quality in offspring is generated from either the intrinsic effects of good genes, or from interactions between compatible genes from the parents. In inbreeding, loss of heterozygosity contributes to the overall decreased reproductive success, but when individuals engage in extra-pair copulations, mating between genetically dissimilar individuals leads to increased heterozygosity.
Extra-pair copulations involve a number of costs and benefits for both male and female animals. For males, extra-pair copulation involves spending more time away from the original pairing in search of other females. This risks the original female being fertilized by other males while the original male is searching for partners, leading to a loss of paternity. The tradeoff for this cost depends entirely on whether the male is able to fertilize the other females’ eggs in the extra-pair copulation. For females, extra-pair copulations ensure egg fertilization, and provide enhanced genetic variety with compatible sperm that avoid expression of damaging recessive genes that come with inbreeding. Through extra-pair mating, females are able to maximize the genetic variability of their offspring, providing protection against environmental changes that may otherwise target more homozygous populations that inbreeding often produces.
Whether a female engages in extra-pair copulations for the sake of inbreeding avoidance depends on whether the costs of extra-pair copulation outweigh the costs of inbreeding. In extra-pair copulations, both inbreeding costs and pair-bond male loss (leading to the loss of paternal care) must be considered with the benefits of reproductive success that extra-pair copulation provides. When paternal care is absent or has little influence on offspring survivability, it is generally favorable for females to engage in extra-pair mating to increase reproductive success and avoid inbreeding.
Gaps
Inbreeding avoidance has been studied via three main methods: (1) observing individual behavior in the presence and absence of close kin, (2) contrasting costs of avoidance with costs of tolerating close inbreeding, and (3) comparing observed and random frequencies of close inbreeding. No method is perfect, giving rise to questions about the completeness and consistency of the inbreeding avoidance hypothesis. Although the first option, individual behavioral observation, is preferred and most widely used, there is still debate over whether it can provide definitive evidence for inbreeding avoidance.
A majority of the literature on inbreeding avoidance was published at least 15 years ago, allowing for growth and development of the study through contemporary experimental methods and technology. Molecular techniques such as DNA fingerprinting have become more advanced and accessible, improving the efficiency and accuracy of measuring relatedness. Studying inbreeding avoidance in carnivores has garnered increased interest due to ongoing work to explain their social behaviors.
References
Evolutionary biology
Population genetics
Organisms by adaptation | Inbreeding avoidance | [
"Biology"
] | 3,415 | [
"Organisms by adaptation",
"Evolutionary biology"
] |
44,448,550 | https://en.wikipedia.org/wiki/Navitaire | Navitaire LLC is a subsidiary of Amadeus IT Group. Navitaire primarily offers systems for passenger reservations, travel commerce, ancillary revenue and merchandising, as well as revenue accounting and revenue management to airlines and rail companies.
Overview
Navitaire is a subsidiary of Amadeus that provides technology services to the airline and rail industries. Its headquarters are in Minneapolis with offices in London, Manila, Salt Lake City, and Sydney. It has data centers in Minneapolis, Salt Lake City, and Sydney. David Evans has held the role of global managing director since 2013.
Navitaire has approximately 60 clients and 750 employees. it typically works with low-cost carriers (LCC) and hybrid airlines and is the leading passenger service system provider for the LCC market. As of 2014, the firm serves 43% of the top 100 LCCs, and 47% of the top 30 LCCs as measured by seats sold per week. Clients include airlines Wizz Air, Jetstar, Spirit Airlines, Azul Brazilian Airlines, HK Express, and Volaris. The company also works with railway company SNCF and its subsidiary iDTGV.
History
Navitaire was founded as PRA Solutions in 1993 by Accenture. It initially provided airline revenue accounting software and revenue protection software for airlines. The company then developed a direct-distribution platform to book airline reservations, "World Network," an alternative to the global distribution system traditionally used by travel agents to sell airline flights. In 2000, PRA Solutions purchased the Open Skies reservation system from Hewlett Packard, and in 2001, changed its name to Navitaire.
In 2002, the firm implemented codeshare technology for Virgin Blue, and the company later introduced multi-city bookings at the request of Jetstar. Following Hewlett Packard's announcement in 2001 of its plans to discontinue support for the HP3000 hardware that the Open Skies system operated on, Navitaire developed a replacement reservation system called New Skies. The company began converting clients to the new system in 2005. Navitaire was acquired by Amadeus in 2015.
Products and services
Navitaire's passenger service system is New Skies, which was introduced in 2005. It introduced features including a low fare finder and multi-city bookings. The system provides reservations via the Internet, call centers, and through global distribution systems (GDS) using a ticketless model as well as enabling e-ticketing. It also allows integration with other travel services such as travel insurance and car rental, as well as codeshare agreements with other airlines. As of 2010, the firm had 80 such codeshare connections to partner airlines, as well as nine GDS connections.
Navitaire offers additional products and services including Travel Commerce, a platform to aid in ancillary revenue generation and a loyalty system. The company also offers real-time reporting, revenue accounting software and revenue management. It provides a reservations management system for railways called Navitaire Rail, which facilitates multi-channel distribution sales and station check-ins for rail carriers.
Awards
In October 2010, Navitaire was awarded for Best Sales and Distribution Innovation at the 4th Annual Budgies World Low Cost Airlines Awards. The company was awarded Innovation of the Year in the category of Ancillary Revenue & Merchandising at Airline Information's 2013 Mega Awards, after being named a runner-up in the Ancillary Revenue & Merchandising - Most Innovative Technology category at the Mega Awards event held in November 2012. In December 2013, Navitaire received a Tekne Award from Minnesota High Tech Association for its ticketless system and other services. In March 2019, Navitaire became the first passenger revenue accounting provider to be granted ONE Order (00) Capable certification form the International Air Transport Association (IATA).
References
Accenture
Companies based in Minneapolis
Information technology companies of the United States
Computer reservation systems | Navitaire | [
"Technology"
] | 792 | [
"Computer reservation systems",
"Computer systems"
] |
44,449,911 | https://en.wikipedia.org/wiki/Right2Water | Right2Water is a campaign to commit the European Union and member states to implement the human right to water and sanitation.
It has three stated goals:
Guaranteed water and sanitation for all in Europe.
No liberalisation of water services.
Universal (Global) access to water and sanitation.
The European Citizens' Initiative (ECI) represented more than 120 NGO and was supported by the German and Austrian trade unions. The backbone of the ECI was the European Federation of Public Service Unions (EPSU) whose President Anne-Marie Perret was also the president of the citizens Committee. On 21 March 2013, it became the first ECI to collect more than a million signatures and they reached the minimum quota of signatures in seven countries on 7 May 2013. It stopped the signature collection on 7 September 2013, with a total of 1,857,605 signatures. The initiative was submitted to the European Commission in December 2013 and the public hearing took place on 17 February 2014 at the European Parliament. In March 2014, the commission has adopted the Communication in response to the Right2Water initiative. On 1 July 2015 the Roadmap for the evaluation of the Drinking Water Directive has been published by the European Commission.
In response, the European Parliament criticised the commission for failing the meet the initiative's demands. The report by Sinn Féin MEP Lynn Boylan called on the Commission "to recognise that affordable access to water is a basic human right."
In 2010, three years before the petition, Paris was the first European local entity to have concluded the remunicipalization process of water and sanitation, entrusted to Eau de Paris.
From 2010 until 2022 many other cities and regions have declared its support to the human right to water (like Slovenia and Andalucia) many remunicipalisations also have taken place.
The commission’s answer
On 19 March 2014 the commission partly meet the proposals. The commission included the following:
A reinforcement of the implementation of the water quality legislation, building on the commitments presented in the 7th EAP and the Water Blueprint;
Launching of an EU-wide public consultation on the Drinking Water Directive, notably in view of improving access to quality water in the EU;
Improvement of the transparency for urban wastewater and drinking water data management and explore the idea of benchmarking water quality;
Set-up of a more structured dialogue between stakeholders on transparency in the water sector;
Cooperation with existing initiatives to provide a wider set of benchmarks for water services;
Stimulation of innovative approaches for development assistance (e.g. support to partnerships between water operators and to public-public partnerships); promote sharing of best practices between Member States (e.g. on solidarity instruments) and identify new opportunities for cooperation.
Advocation of universal access to safe drinking water and sanitation as a priority area for future Sustainable Development Goals.
Revision of the Drinking Water Directive
On 1 February 2018 Karmanu vella and Frans Timmermans announced the revision of the Drinking water Directive 'because this is a topic which is close to Europeans' hearts. Water was the subject of the first ever successful European Citizens' Initiative, with over 1.6 million people supporting the Right2Water Initiative before it was submitted to the Commission. EPSU the main organiser of the ECI reacted saying that "the European Commission missed an opportunity to implemented the human right to water". On 16 December 2020, the European Parliament formally adopted the revised Drinking Water Directive. The Directive will enter in force on 12 January 2021, and Member States will have two years to transpose it into national legislation.
See also
Human rights
References
European Union
Initiatives
Political organisations based in the Republic of Ireland
Water supply
Sanitation
de:Wasser ist ein Menschenrecht! | Right2Water | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 750 | [
"Hydrology",
"Water supply",
"Environmental engineering"
] |
71,659,624 | https://en.wikipedia.org/wiki/PU%20Vulpeculae | PU Vulpeculae is a very slowly evolving symbiotic nova in the northern constellation of Vulpecula, abbreviated PU Vul. It is too faint to be visible to the naked eye, reaching a maximum apparent visual magnitude of 8.7 following a minimum of 16.6. The system is located at a distance of approximately 17,000 light years from the Sun based on parallax measurements.
The brightening of this object during April 1979 was independently discovered by Y. Kuwano and M. Honda. At detection, it had a visual magnitude of 9.1 and was initially designated Nova Vulpeculae 1979. Photographic plates taken since November 1977 showed a dramatic increase of five magnitudes at the time of discovery. In September, 1978, it had been catalogued as a stellar class of M4. A search of Harvard Observatory archival plates taken since 1898 showed several smaller eruptions of this star.
For much of 1979 the object had a brightness of magnitude 8.9 while varying by a magnitude of 0.15 with a period of about 80 says, then it began to fade rapidly in 1980, reaching a minimum magnitude of 13.65 in August. At this minimum, the spectrum showed bands of the TiO molecule, which is typical of lower temperature M-type stars. It began to brighten again at about the same rate as the decrease, reaching magnitude 8.5 in August, 1981. The star remained mostly stable at this level for about a year, displaying a pair of brief dips in brightness during 1982. Polarization of the light indicated the formation of large dust particles, which was suggested as a cause of the brightness decrease in 1980.
A soft X-ray halo was detected around the object in 1980, as well as a weaker ring-like structure. Infrared observations in 1980 suggested this is a symbiotic binary star system consisting of a variable, evolved star that has expanded to fill its Roche lobe and is periodically transferring mass to a faint, compact companion. However, the system did not show the expected emission lines from the infalling material. The spectrum at the minimum indicated the evolved star is a giant of class M6. The hot component showed a supergiant or bright giant spectrum that changed from a class of F5 in 1983 to A2 in 1986, while the brightness remained near magnitude 8.7. During this time the hot component changed from resembling a supergiant with a temperature similar to the Sun into a white dwarf smaller than the sun with a temperature in excess of . Emission lines became visible in 1988 as the outer layers were shed and became a nebula surrounding the white dwarf remnant.
The brightness of this object finally began to steadily decrease in 1987. By September 1989, it had declined to magnitude 10.5. The spectrum began to resemble a nebula, which came from a hot stellar wind expanding at a velocity of or more. In 1993, the emission features from the wind temporarily disappeared, which suggested the system was undergoing an eclipse. The data indicated this is an eclipsing binary with an orbital period of , which meant the orbital plane is nearly aligned with the line of sight from the Earth. An eclipse would explain the unusual minimum during 1980. The cool component was determined to be on the asymptotic giant branch and is pulsating with a period of 217 days, making it a Mira variable. The compact companion is a white dwarf with mass estimated at 60% of the mass of the Sun. The system displays an "illumination effect" caused by the ionization of the stellar wind from the giant by the dwarf. The light curve of this variation suggests an orbital eccentricity of at least 0.16.
References
Further reading
Mira variables
White dwarfs
Symbiotic novae
Eclipsing binaries
Vulpecula
Vulpeculae, PU | PU Vulpeculae | [
"Astronomy"
] | 774 | [
"Vulpecula",
"Constellations"
] |
71,659,775 | https://en.wikipedia.org/wiki/Josephson%20diode | A Josephson diode (JD) is a special type of Josephson junction (JJ), which conducts (super)current in one direction better that in the opposite direction. In other words it has asymmetric current-voltage characteristic. Since Josephson diode is a superconducting device, the asymmetry of the supercurrent transport is the main focus of attention. Opposite to conventional Josephson junctions, the critical (maximum) supercurrents and for opposite bias directions are different by absolute values ().
In the presence of such a non-reciprocity, the bias currents of any magnitude in the range between and can flow without resistance in only one direction.
This asymmetry, characterized by the ratio of critical currents , is the main figure of merit of Josephson diodes and is the subject of new developments and optimizations.
The Josephson diode effect can occur, e.g., in superconducting devices where time reversal symmetry and inversion symmetry are broken.
Josephson diodes can be subdivided into two categories, those requiring an external (magnetic) field to be asymmetric and those not requiring an external magnetic field --- the so-called “field-free” Josephson diodes (more attractive for applications). In 2021, the Josephson diode was realized in the absence of applied magnetic field in a non-centrosymmetric material,
followed shortly by the first realization of the zero-field Josephson diode in an inversion-symmetric device.
History
Since decades the physicists tried to construct Josephson junction devices with asymmetric critical currents. This didn't involve new physical principles or advanced (quantum) material engineering, but rather electrical engineering tricks like combining several JJs in a special way (e.g. asymmetric 3JJ SQUID) or specially designed long JJs or JJ arrays, where Josephson vortex transport was asymmetric in opposite directions. After all, if one does not look inside the device, but treats such a device as a black box with two electrodes, its current-voltage characteristic is asymmetric with . Such devices were especially popular in the context of Josephson ratchets — devices used to rectify random or deterministic signals with zero time-average. These devices can be subdivided into several classes:
asymmetric SQUID-like devices: proposals and experimental implementations
long JJs with asymmetric vortex depinning currents: experimental implementations
Josephson fluxonic diodes
JJ arrays: proposals and experiments.
intermediate length JJ with specially modulated properties/geometry: e.g. tunable -JJs and in-line JJs made of Nb and YBCO showing record critical current asymmetry ratios of .
Starting from 2020 one observes a new wave of interest to the systems with non-reciprocal supercurrent transport based on novel materials and physical principles.
In 2020, a superconducting diode effect (see below) was demonstrated in an artificial [Nb|V|Ta|] superlattice. (not yet a Josephson system). It was based on the previous proposal with design similar to conventional semiconducting p-n junctions, but utilizing hole and electron doped superconductors. Next year the Josephson diode was demonstrated in van der Waals heterostructure of NbSe2/Nb3Br8/NbSe2. In this heterostructure the weak link (Josephson barrier) Nb3Br8 is a quantum material that is predicted to be an obstructed atomic insulator / Mott insulator and is non-centrosymmetric, i.e., it distinguishes between electrons with positive and negative momentum. However, the asymmetry of such device was very low ().
A Josephson diode at zero applied field was observed in small twist-angle trilayer graphene, a system which possesses in-plane inversion symmetry. In this case, the superconducting state itself is responsible for the breaking of time reversal symmetry and in-plane inversion symmetry.
In 2022, a Josephson diode in symmetric Al|InAs(2DEG)|Al junction (array) was demonstrated, exhibiting asymmetry relevant for applications.
Josephson diode based on Nb|Pt+YIG|Nb heterostructure operates at zero magnetic field and with the possibility to reverse its direction demonstrates similar asymmetry ratio at .
Josephson diode using the topological semi-metal NiTe2 as a barrier, demonstrates at .
In-depth review of recent developments.
Superconducting diode effect
The superconducting diode effect is an example of nonreciprocal superconductivity, where a material is superconducting in one direction and resistive in the other. This leads to half-wave rectification when a square wave AC-current is applied. In 2020, this effect was demonstrated in an artificial [Nb/V/Ta]n superlattice. The phenomenon in the Josephson diode is believed to originate from asymmetric Josephson tunneling. Unlike conventional semiconducting junction diodes, the superconducting diode effect can be realized in Josephson junctions as well as junction-free bulk superconductors.
Theories
Currently, the precise mechanism behind the Josephson diode effect is not fully understood. However, some theories have emerged that are now under theoretical investigation. There are two types of Josephson diodes, relating to which symmetries are being broken. The inversion breaking Josephson diode, and the Josephson diode breaking inversion breaking and time-reversal. The minimal symmetry breaking requirement for forming the Josephson diode is inversion symmetry breaking, and is required to obtain nonreciprocal transport. One proposed mechanism originates from finite momentum Cooper pairs. It may also be possible that the superconducting diode effect in the JD originates from self-field effects, but this still has to be rigorously studied.
Figures of merit
Depending on the potential application different parameters of the Josephson diodes, from operation temperature to their size can be important. However, the most important parameter is the asymmetry of critical currents (also called non-reciprocity). It can be defined as dimensionless ratio of larger to smaller critical currents
to be always positive and lay in the range from 1 (symmetric JJ) to (infinitely asymmetric one). Instead, some researchers use the so-called efficiency, defined as
It lays in the range from 0 (symmetric system) to 1 (infinitely asymmetric system).
Among other things the efficiency shows the theoretical limit for thermodynamic efficiency (ratio of output to input power) that can be reached by the diode during rectification.
Intuitively it is clear that the larger the asymmetry is, the better the diode performs. A quantitative analysis showed that a large asymmetry allows one to achieve rectification in a wide range of driving current amplitudes, a large counter current (corresponding to a heavy load), against which rectification is still possible, and a large thermodynamic efficiency (ratio of output dc to input ac power).
Thus, to create a practically relevant diode one should design a system with high asymmetry. The asymmetry ratios (efficiency) for different implementations of Josephson diodes are summarized in the table below.
Size. Previously demonstrated Josephson diodes were rather large (see the table), which hampers their integration into micro- or nano-electronic superconducting circuits or stacking. Novel devices based on heterostructures can potentially have 100 nm-scale dimensions, which is difficult to achieve using previous approaches with long JJs, fluxons, etc.
Voltage. Important parameter of any nano-rectifier is the maximum dc voltage produced. See the table for comparison.
Operating temperature. Ideally one would like to operate the diode in wide temperature range. Obviously, an upper limit in operation temperature is given by the transition temperature of the superconducting material(s) used to fabricate the Josephson diodes. In the table below we quote the operating temperature for which the other parameters such as asymmetry are quoted. Many novel diodes, unfortunately, operate below 4.2K.
See also
Josephson effect
Josephson junction
References
Diodes
Josephson effect | Josephson diode | [
"Materials_science"
] | 1,730 | [
"Superconductivity",
"Josephson effect"
] |
71,664,230 | https://en.wikipedia.org/wiki/Glock%20switch | A Glock switch (sometimes called a button or a giggle switch) is a small device that can be attached to the rear of the slide of a Glock handgun, changing the semi-automatic pistol into a selective fire machine pistol capable of fully automatic fire. As a type of auto sear, it functions by applying force to the trigger bar to prevent it from limiting fire to one round of ammunition per trigger pull. This device by itself, regardless if it is installed on a slide or not, is classified by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) to be a machine gun, making possession of the device illegal in the United States under most circumstances.
Operation
A Glock switch functions by applying force to a semi-automatic pistol's trigger bar to prevent it from limiting fire to one round of ammunition per trigger pull. Normally, in a semiautomatic pistol, after firing, the trigger bar catches the firing pin until the trigger is released, but when depressed by the switch it does not catch. A Glock switch thus converts the weapon into a machine pistol capable of automatic fire. The device is roughly the size of a United States quarter, and when installed on the rear of the slide on a Glock pistol (replacing the slide cover plate), adds a selective fire switch; flipping the switch sets the weapon to full automatic mode, which is capable of firing as many rounds per minute as the short-recoil action allows.
History
A patent for the Glock auto-sear was filed in 1996 and approved in 1998, with its invention credited to Venezuelan Jorge A. Leon, who claims to have invented the device in 1987.
The first reported appearance of Glock switches in the United States occurred in 2002 when an Argentinian was arrested for sending Glock switches among other illegal firearms to the United States, with 16 later being recovered by the ATF in 2003.
A handgun with a Glock switch attached fits the definition of a machine gun under United States federal law. The 1986 Firearm Owners Protection Act made new machine guns illegal for civilians to own, banning "possession and transfer of new automatic firearms and parts that fire bullets without stopping once the trigger is depressed", with the exception of machine guns manufactured prior to May 19, 1986. The penalties for possession of an unregistered machine gun in the United States are up to a $250,000 fine and prison sentences of up to 10 years.
In 2019, the ATF recovered thousands of the devices which were imported from China. In 2021 and 2022, people have been manufacturing the switch devices with 3D printers. In March 2022, a Vice News investigation learned that the federal prosecutions which involved conversion devices have been rising since 2017. They determined that from 2017 to 2022, advances in low-cost 3D printers and global commerce on the internet have made the devices available for as little as US$20. In 2022, federal authorities documented a dramatic rise in the prevalence of the Glock switches.
Legality
According to the American ATF, "A Glock Switch is a part which was designed and intended for use in converting a semi-automatic Glock pistol into a machine gun; therefore, it is a "legal machine gun" as defined in 26 U.S.C. 5845(b)."
See also
Hell-fire trigger
Bump stock
Gun politics in the United States
September 2024 Birmingham shooting
References
External links
Video More 'Glock Switches' confiscated in Tennessee
Video Penny-sized 'Glock switch' turns handgun into automatic weapon
Firearm actions
Gun politics in the United States
Firearm components | Glock switch | [
"Technology"
] | 726 | [
"Firearm components",
"Components"
] |
71,664,437 | https://en.wikipedia.org/wiki/Liu%20Yunbin | Liu Yunbin () (1925 – 21 November 1967) was a Chinese nuclear chemist and the son of former President of the People's Republic of China Liu Shaoqi.
Early life
Liu was born on 1925 in Anyuan District of Pingxiang to Liu Shaoqi and He Baozhen. When he was two years old, he was sent back to Liu Shaoqi's hometown in Ningxiang County, Hunan for foster care. In 1934, his mother was executed while in captivity by the Kuomintang.
In July 1938, the Chinese Communist Party brought Liu to Yan'an to reunite with his father. In the autumn of the same year, at the age of 13, Liu started studying at Yan'an Education Primary School.
Education and scientific career
In 1939, the Central Committee of the Chinese Communist Party decided to send a group of children of party revolutionaries to study in the Soviet Union. In November 1939 Liu and his sister Liu Aiqin arrived at the children's home in Monino, where Mao Zedong's sons Mao Anying and Mao Anqing were also living. While in Soviet Union, Liu was known by Russian name 'Klim' (Клим).
After one semester of study, Liu Yunbin moved to Interdom, which was 300 kilometers away from Moscow, at the city of Ivanovo, and was sponsored by the International Red Aid of the Soviet Union. During his time at the school, he studied very hard and in June 1941, following the start of the German invasion of the Soviet Union, Liu actively participated in the labors organized by the International Children's Institute, such as land reclamation, logging, and moving firewood. He also took the initiative to donate blood for the Soviet Red Army soldiers fighting in the frontline. He was selected as one of the leaders of the International Children's Institute student union, and soon joined the Komsomol and served as the head of the organization in the International Children's Academy.
After graduation from high school in 1945, Liu was admitted to the Moscow Iron and Steel Institute, where he majored in smelting. During his time in the institution, he also joined the Communist Party of the Soviet Union and after graduation, he was admitted to the Department of Chemistry at Moscow State University with honors and as a graduate student in radiochemistry. He graduated in 1955 with an associate doctorate degree and entered the Moscow University Institute of Chemistry as a senior researcher. In a 1955 letter to Liu Yunbin, Liu Shaoqi stated:
When your personal interest is in conflict with the interest of the Party, I believe you can sacrifice your own interest for the sake of the Party and the country."
In 1957, he returned to China, where he resided in his father's residence in Zhongnanhai for a few days, before moving to Fangshan County, Shanxi, 50 kilometers away from Beijing, to work at the China Institute of Atomic Energy (Institute 401), which was one of the earliest nuclear weapons research institutes in China. He made outstanding contributions to nuclear energy research and was awarded the title of associate researcher.
In 1959, when Sino-Soviet relations deteriorated, the Soviet Union refused to provide China with technical materials required to develop the atomic bomb. In 1961, researchers from the First Institute of the China Institute of Atomic Energy were transferred to the China Nuclear Fuel Component Factory (Factory 202) at Baotou, Inner Mongolia Autonomous Region, where they set up a second laboratory, which was responsible for the research into thermonuclear materials.
In the winter of 1962, Liu Yunbin arrived at the 202 Factory, where he was appointed by his superiors as the director of the Second Research Office. The office under his leadership began research and organizational work for the atomic bomb project and, on 16 October 1964, China's first atomic bomb was successfully detonated at the Lop Nur test site, which resulted in China becoming the fifth nuclear power in the world and the first Asian nation to possess nuclear capability.
Downfall and death
In 1966 the Cultural Revolution began and Liu was sent to work, where he was tasked with cleaning and digging sewage ditches and other unskilled work. In July 1966, Liu Shaoqi was denounced as a "capitalist roader" and "traitor", and was removed from his position as Party Deputy chairman by Lin Biao.
As a consequence of the downfall of his father, Liu Yunbin was also condemned as a "spy" and "capitalist roader". He was beaten and abused by the Red Guards, who took him to an urban area in Baotou, where he was publicly humiliated at a denunciation rally. On 21 November 1967, Liu took his own life by lying on the railroad tracks north of the residential area where his family lived.
Liu's father died on 12 November 1969, in Kaifeng, Henan, due in part to maltreatment and torture in custody. Following the end of the Cultural Revolution in 1976 with the death of Mao Zedong, Liu Yunbin was posthumously rehabilitated and his reputation restored in 1978. In the same year, a solemn memorial service was conducted for him at the 202 Factory Club. Liu Shaoqi was posthumously rehabilitated in 1980.
On 16 April 2015, Russian Ambassador to China Andrey Denisov awarded the Jubilee Medal "70 Years of Victory in the Great Patriotic War 1941–1945" to 32 Chinese citizens, including Liu Yunbin, who was posthumously awarded the medal.
Personal life
During his time in the Soviet Union, Liu married a Russian woman named Mara Fedotova. The couple had two children; a son named Alexei (Russian: Алексей Климович Федото, Alexei Klimovich Fedotov; Chinese: 刘维宁, Liu Weining) and a daughter named Sonya.
After Liu returned to China in 1957, Mara also moved to China with the children in 1959, which would be the last time the couple would see each other. Due to the tensions between China and Soviet Union, Mara divorced Liu and returned to Moscow with her two children. Liu later married Li Miaoxiu, with whom he had two sons, Liu Weidong and Liu Weize.
Alexei, who is also known by nickname Alyosha, did not publicly reveal himself as grandson of Liu Shaoqi due to fear of being spied on by the KGB when Sino-Soviet relations further deteriorated. After graduating from Moscow Aviation Institute, he worked at the national aviation space center of the Soviet Union and Roscosmos for a number of years with his identity not known until he was invited by the Government of China to attend the commemoration of the 100th anniversary of Liu Shaoqi's birthday in 1998.
His request to travel to China was rejected as his occupation involved military secrecy. The denial of his request led him to grow anxious to travel to China and therefore to retire from the Russian military early. When his request to travel to China was refused again he filed a lawsuit and in 2003 managed to visit China for the first time, where he met with Liu Shaoqi's living family members, including his wife Wang Guangmei.
He decided to settle in China, where he presently manages an organization called 'Russian-Asian Union of Industrialists and Entrepreneurs' that facilitates trade between China and Russia in Guangzhou. Alexei and his wife have two children, including a daughter named Margarita who is currently serving as the vice chairman of the Russian-Asian Industrial Entrepreneurs Association and Russia-Philippine Business Council.
Liu's daughter Sonya married a Russian American and is currently settled in the United States.
References
1925 births
1967 suicides
1967 deaths
20th-century Chinese chemists
20th-century Chinese scientists
Chemists from Jiangxi
Children of national leaders of China
Children of presidents
Chinese expatriates in the Soviet Union
Foreign Communist Party of the Soviet Union members
Family of Liu Shaoqi
Moscow State University alumni
Nuclear chemists
People from Pingxiang
Suicides by train
Suicides during the Cultural Revolution | Liu Yunbin | [
"Chemistry"
] | 1,629 | [
"Nuclear chemists"
] |
71,665,395 | https://en.wikipedia.org/wiki/Cortinarius%20diaphorus | Cortinarius diaphorus is a species of purple pouch fungus in the genus Cortinarius endemic to Aotearoa New Zealand.
Taxonomy
Cortinarius diaphorus was illustrated and noted as an undescribed species (as C. diaphorus ined.) by Karl Soop in the 11th (2017) edition of his book Cortinarioid Fungi of New Zealand. It was formally described in 2020 by Karl Soop, Andy Nilsen and David Orlovich. The holotype specimen was collected in 2017 on the Lake Christabel Track in Victoria Forest Park. The phylogenetic position of C. diaphorus in the genus Cortinarius is not well resolved, with a weak relationship to C. diaphoides in one ITS+28S phylogeny and no supported relationship in the multigene phylogeny of Soop et al.
Description
The species produces secotioid fruit bodies. The pileus ranges from 15 to 25 mm in diameter. It has a rounded shape with an incurved margin. The surface of the pileus has a smooth texture with small cracks or grooves, giving the surface a mottled appearance, slightly slimy, lavender in colour becoming slightly reddish with age. The gleba is yellow-brown to sienna in colour, with irregular locules (compartments) up to 3 mm long, attached at the top of the stipe and becoming free. The stipe is 15 to 45 mm long and 6 to 10 mm wide, centrally attached, pale violet to purple, extending into the pileus as a pale violet columella. The fruit bodies have a delicate silvery veil and no cortina. Tissues of the fruit body show no reaction to a 5% solution of potassium hydroxide. The basidiospores average 13.8 μm long and 7.6 μm wide, are rusty to tawny in colour, ellipsoid to almond-shaped, strongly warted. The spores don't change colour in contact with Melzer's reagent. Cortinarius diaphorus is distinguished from the other purple secotioid Cortinarius species in New Zealand by the combination of lavender colour of the pileus, pale mottling when young and reddening with age, and the strongly warted spores.
Habitat and distribution
Cortinarius diaphorus occurs in the South Island of New Zealand. It is an ectomycorrhizal fungus, found in forests dominated by Nothofagus species including red beech (N. fusca), silver beech (N. menziesii), and hard beech (N. truncata).
Etymology
The specific epithet diaphorus derives from the Greek διαφορος (diaforos) meaning 'different'. This refers to this species being "similar, yet different" from Cortinarius porphyroideus.
See also
List of Cortinarius species
External links
Cortinarius diaphorus in Biota of New Zealand (additional images).
References
diaphorus
Fungi of New Zealand
Fungus species | Cortinarius diaphorus | [
"Biology"
] | 647 | [
"Fungi",
"Fungus species"
] |
71,665,529 | https://en.wikipedia.org/wiki/LY-2109761 | LY-2109761 is a synthetic compound which acts as a potent and selective inhibitor for the growth factor receptor TGF beta receptor 1. It is used for research into conditions such as pulmonary fibrosis and cancer.
See also
Galunisertib
GW788388
References
Kinase inhibitors | LY-2109761 | [
"Chemistry"
] | 66 | [
"Pharmacology",
"Growth factors",
"Neurochemistry",
"Medicinal chemistry stubs",
"Signal transduction",
"Receptor antagonists",
"Pharmacology stubs"
] |
71,665,866 | https://en.wikipedia.org/wiki/Western%20Engineer | The paddle steamer Western Engineer was the first steamboat on the Missouri River. It was purpose built after a design by Major Stephen Harriman Long by the Allegheny Arsenal in Pittsburgh, for the scientific party of the Yellowstone expedition which Major Long commanded. The paddle wheel was placed in the stern, the steam engine hidden below the waterline, the vessel was heavily armed and had acquired a peculiar appearance intended to inspire fear and awe among the Plains Indians. Her first voyage took her from Pittsburgh to Saint Louis in 1819. The second voyage took her to Fort Lisa, Nebraska the same year. The third voyage took her back to Saint Louis in the spring of 1820, while the fourth voyage was a charting expedition up the Mississippi to the Des Moines Rapids and down to Cape Girardeau, Missouri. A fifth voyage supposed to take her back to Pittsburgh had to be aborted at Smithland, Kentucky due to low water, and she was left there.
Background
The Yellowstone expedition was a military undertaking ordered by Secretary of War John C. Calhoun. Its primary objective was to establish a military fort at the confluence of the Yellowstone River and the Missouri River; the purpose of which was to prevent the infiltration of Hudson's Bay Company traders into the Great Plains. Its secondary objective was a scientific expedition to explore and map Missouri and the upper Mississippi watershed. Hence, the expedition consisted of a military component under Colonel Henry Atkinson of the 6th Infantry and a scientific component under Major Stephen Harriman Long of the Topographical Engineers. Both components would use steamboats and the scientific party would continue upstream Missouri when the military party had reached the Yellowstone River.
Design
Western Engineer was built at the Allegheny Arsenal in Pittsburgh, after Major Long's design and under his supervision. The paddle wheel was placed in the stern, the steam engine hidden below the waterline, the vessel was heavily armed and had acquired a peculiar appearance intended to inspire fear and awe among the Plains Indians. At the very front of the bow was a metal pipe that ended in a stylized snake's head from which steam from the steam engine could suddenly be released in a large cloud. The boat was said to look like a scaly monster with a vessel on its back, with gaping gun ports and overflowing with weapons. It had a shallow draft and was very narrow in order to maneuver in the restricted and shallow channels of the upper Missouri River. The draft was only 19 inches at full load and it was only 13 feet wide with a displacement of 30 tons. Despite its clever design, the Western Engineer did not operate effectively on the Missouri River. Upstream speed was not faster than that of a common riverboat and the silt-filled river water often clogged the steam boilers.
Complement
The commander of the scientific component Major Long was allowed to pick the members of the scientific party. Dr. William Baldwin was surgeon and botanist, Augustus E. Jessup geologist, Thomas Say zoologist, Titian Peale assistant naturalist, and Samuel Seymour illustrator. Of the military men in the scientific component, Major Thomas Biddle was official diarist while Lieutenant James Duncan Graham and Cadet William Swift were assistant topographers. The Indian Agent Major Benjamin O'Fallon accompanied the expedition. There were also a sergeant and eight privates for manual labor and close protection. The actual crew of the Western Engineer was a pilot, a clerk, a carpenter, a steam engineer and two boys. The steam engineer was actually a mechanic, as the Army could not afford to pay for an experienced engineer. Long commanded the boat aided by Lieutenant Graham, who took command and remained aboard when the party traveled overland in the summer of 1820.
Voyages
The first voyage of the Western Engineer began on May 5, 1819 under command of Major Long. With scholars, officers and artillerists aboard and followed by keelboats with troops from the 6th U.S. Infantry, it took her 36 days down the Ohio and up the Mississippi. At Maysville, Kentucky strong winds pushed her into the riverside, but she passed the Falls of the Ohio (at present Louisville, Kentucky) without difficulties and reached Saint Louis on June 9, 1819.
The second voyage began on June 21, 1819 as part of the Yellowstone expedition. Going upriver on the Missouri the small Western Engineer was slowed by strong counter-currents and hindered by sandbars and log jams of driftwood. The valves of her engine fatigued by the sand in the river water used in her engines became fatigued by the alluvial sand in the river water used in her boilers. She reached Fort Lisa close to present day Omaha Nebraska on September 9, 1819. The scientific party of the expedition then went into winter quarters at a point Major Long called Engineer Cantonment.
The failure of the steamboats of the military party to follow Western Engineer led to a change of plans for the scientific party. It would leave the Western Engineer and proceed on foot along the Platte River towards the Rocky Mountain on what would become Long's Expedition of 1820. In the spring of 1820, Major Long therefore handed over the command of the Western Engineer to Lieutenant Graham and ordered him to proceed to Saint Louis.
After arriving at Saint Louis, Lieutenant Graham then followed orders and took the Western Engineer on her fourth voyage; up the Mississippi to the Des Moines Rapids and then down to Cape Girardeau, while charting the course of the river. At the end of this voyage, Major Long wanted her to return to Pittsburgh, but the water stage on the Ohio was too low even for the Western Engineer to undertake this voyage, and she was left at Smithland, Kentucky.
References
Citations
Cited literature
Conniff, Richard (2011), The Species Seekers, W.W. Norton & Co.
Genoways Hugh H. & Ratcliffe, Brett C. (2008), "Engineer Cantonment, Missouri Territory, 1819-1820: America's First Biodiversity Inventory," Great Plains Research 18:3-31.
James, Edwin (1823). Account of an Expedition to the Rocky Mountains. Philadelphia.
Johnson, Leland R. (1977). Men, Mountains and Rivers. An Illustrated History of the Huntington District, U.S. Corps of Engineers, 1754-1974. Washington, D.C.: U.S. Government Printing Office.
Kotar, S.L. & Gessler, J.E. (2009), The Steamboat Era, McFarland & Co.
Nichols, Roger L. (1971). "Stephen Long and Scientific Exploration on the Plains." Nebraska History 52:50-64.
Nichols, Roger L. & Halley, Patrick L. (1995). Stephen Long and American Frontier Exploration. University of Oklahoma Press.
Petersen, William J. (1968), Steamboating on the Upper Mississippi, Dover Publications.
Prucha, Francis P. (1964), Guide to the Military Posts of the United States, State Historical Society of Wisconsin.
Shallat, Todd (1994), Structures in the Stream, University of Texas Press.
Thwaites, Reuben Gold (1905). "Preface to Volume XIV-XVII." Early Western Travels 1748-1846: Volume XIV. Cleveland, Ohio: The Arthur H. Clark Co.
Steamboats of the Missouri River
Steamboats of the Mississippi River
Paddle steamers of the United States
Exploration ships
1819 in the United States
1820 in the United States
Exploration of North America
United States Army Corps of Engineers
Smithland, Kentucky
Ships built in Pittsburgh | Western Engineer | [
"Engineering"
] | 1,505 | [
"Engineering units and formations",
"United States Army Corps of Engineers"
] |
71,666,526 | https://en.wikipedia.org/wiki/Fondazione%20Eni%20Enrico%20Mattei | Fondazione Eni Enrico Mattei (FEEM) is a nonprofit, nonpartisan research center and think tank based in Milan with offices in Venice and Viggiano.
FEEM is considered a leading international research center for the study of energy and environmental issues,
focusing globally on the environment, sustainable development and governance. The Foundation's mission is the research-based improvement of the quality of public and private sector decision-making.
History
Fondazione Eni Enrico Mattei was organized by members of the Ente Nazionale Idrocarburi (ENI) and others, beginning in 1982. The first board meeting occurred in 1987, setting down the principles for its activities. Named to honor Enrico Mattei, FEEM was formally recognized on June 7, 1989 by the President of the Italian Republic Francesco Cossiga.
Leadership
As of 21 September 2020, Alessandro Lanza was appointed as the Executive Director of Fondazione Eni Enrico Mattei by the FEEM Board of Directors, succeeding Paolo Carnevale. The chair of FEEM's board of directors is Lucia Calvosa.
Work
Fondazione Eni Enrico Mattei carries out research and provides objective analysis on a range of issues relating to the environment, energy and the global economy,
including mitigation and adaptation to climate change.
FEEM works with an international and interdisciplinary network of researchers in innovative programs, providing and promoting training in specialized research fields, disseminating the results of their studies through various communication channels and informing policy makers through participation in various institutional forums.
In 2009 FEEM and the Giorgio Cini Foundation co-founded the International Center for Climate Governance, renamed the Initiative on Climate Change policy and Governance (ICCG) as of 2017. ICCG is based in Venice on the island of San Giorgio Maggiore. It serves as an international disseminator of research on climate change policy and governance. In 2012, ICCG released the first in a series of international rankings of think tanks engaged in research on climate change science, economics, and policy.
Among other activities, in April 2019 FEEM worked with the Sustainable Development Solutions Network (SDSN) to bring together a worldwide group of experts on decarbonization technologies, resulting in the report The Roadmap to 2050: A Manual for Countries to Decarbonize by Mid-Century.
External links
Fondazione Eni Enrico Mattei Official website (also in English)
Fondazione Eni Enrico Mattei Working Papers, BE Press
References
Energy research institutes
Environmental research institutes
Multidisciplinary research institutes
Environmental organisations based in Italy
Research institutes in Italy
Environmental organizations established in 1989
Research institutes established in 1989
1989 establishments in Italy
International climate change organizations
Think tanks based in Italy | Fondazione Eni Enrico Mattei | [
"Engineering",
"Environmental_science"
] | 552 | [
"Energy research institutes",
"Energy organizations",
"Environmental research institutes",
"Environmental research"
] |
71,666,724 | https://en.wikipedia.org/wiki/William%20M.%20Hess | William Manert Hess (April 28, 1928 - August 22, 2017) was a Columbian Chemicals Company scientist known for contributions to characterization of carbon black dispersion in rubber.
Education
Hess completed his education at Long Island University.
Career
Hess joined the Columbian Chemicals Company in 1950. He was promoted to the position of manager of the Columbian Physics Laboratory in 1955. He was promoted to Senior Scientist in 1961. Hess retired in 1987, but continued as a consultant until his death.
Hess was a prolific researcher and author in the area of carbon black technology. His most cited work investigated the application of electron microscopy to the study of carbon black. His works on characterizing the distribution and dispersion of carbon black in rubber and its blends, and on the application of fractal descriptors are also highly cited. He was the 1985 recipient of the Melvin Mooney Distinguished Technology Award from the ACS Rubber Division. He received the 1993 Lavoisier Medal of the Société Chimique de France. He received an Honoris Causa Doctorate from the University of Haute-Alsace in Mulhouse France in 2000.
References
1928 births
2017 deaths
Polymer scientists and engineers
20th-century American engineers | William M. Hess | [
"Chemistry",
"Materials_science"
] | 240 | [
"Polymer scientists and engineers",
"Physical chemists",
"Polymer chemistry"
] |
71,667,849 | https://en.wikipedia.org/wiki/Dirac%E2%80%93K%C3%A4hler%20equation | In theoretical physics, the Dirac–Kähler equation, also known as the Ivanenko–Landau–Kähler equation, is the geometric analogue of the Dirac equation that can be defined on any pseudo-Riemannian manifold using the Laplace–de Rham operator. In four-dimensional flat spacetime, it is equivalent to four copies of the Dirac equation that transform into each other under Lorentz transformations, although this is no longer true in curved spacetime. The geometric structure gives the equation a natural discretization that is equivalent to the staggered fermion formalism in lattice field theory, making Dirac–Kähler fermions the formal continuum limit of staggered fermions. The equation was discovered by Dmitri Ivanenko and Lev Landau in 1928 and later rediscovered by Erich Kähler in 1962.
Mathematical overview
In four dimensional Euclidean spacetime a generic fields of differential forms
is written as a linear combination of sixteen basis forms indexed by , which runs over the sixteen ordered combinations of indices with . Each index runs from one to four. Here are antisymmetric tensor fields while are the corresponding differential form basis elements
Using the Hodge star operator , the exterior derivative is related to the codifferential through . These form the Laplace–de Rham operator which can be viewed as the square root of the Laplacian operator since . The Dirac–Kähler equation is motivated by noting that this is also the property of the Dirac operator, yielding
This equation is closely related to the usual Dirac equation, a connection which emerges from the close relation between the exterior algebra of differential forms and the Clifford algebra of which Dirac spinors are irreducible representations. For the basis elements to satisfy the Clifford algebra , it is required to introduce a new Clifford product acting on basis elements as
Using this product, the action of the Laplace–de Rham operator on differential form basis elements is written as
To acquire the Dirac equation, a change of basis must be performed, where the new basis can be packaged into a matrix defined using the Dirac matrices
The matrix is designed to satisfy , decomposing the Clifford algebra into four irreducible copies of the Dirac algebra. This is because in this basis the Clifford product only mixes the column elements indexed by . Writing the differential form in this basis
transforms the Dirac–Kähler equation into four sets of the Dirac equation indexed by
The minimally coupled Dirac–Kähler equation is found by replacing the derivative with the covariant derivative leading to
As before, this is also equivalent to four copies of the Dirac equation. In the abelian case , while in the non-abelian case there are additional color indices. The Dirac–Kähler fermion also picks up color indices, with it formally corresponding to cross-sections of the Whitney product of the Atiyah–Kähler bundle of differential forms with the vector bundle of local color spaces.
Discretization
There is a natural way in which to discretize the Dirac–Kähler equation using the correspondence between exterior algebra and simplicial complexes. In four dimensional space a lattice can be considered as a simplicial complex, whose simplexes are constructed using a basis of -dimensional hypercubes with a base point and an orientation determined by . Then a h-chain is a formal linear combination
The h-chains admit a boundary operator defined as the (h-1)-simplex forming the boundary of the h-chain. A coboundary operator can be similarly defined to yield a (h+1)-chain. The dual space of chains consists of -cochains , which are linear functions acting on the h-chains mapping them to real numbers. The boundary and coboundary operators admit similar structures in dual space called the dual boundary and dual coboundary defined to satisfy
Under the correspondence between the exterior algebra and simplicial complexes, differential forms are equivalent to cochains, while the exterior derivative and codifferential correspond to the dual boundary and dual coboundary, respectively. Therefore, the Dirac–Kähler equation is written on simplicial complexes as
The resulting discretized Dirac–Kähler fermion is equivalent to the staggered fermion found in lattice field theory, which can be seen explicitly by an explicit change of basis. This equivalence shows that the continuum Dirac–Kähler fermion is the formal continuum limit of fermion staggered fermions.
Relation to the Dirac equation
As described previously, the Dirac–Kähler equation in flat spacetime is equivalent to four copies of the Dirac equation, despite being a set of equations for antisymmetric tensor fields. The ability of integer spin tensor fields to describe half integer spinor fields is explained by the fact that Lorentz transformations do not commute with the internal Dirac–Kähler symmetry, with the parameters of this symmetry being tensors rather than scalars. This means that the Lorentz transformations mix different spins together and the Dirac fermions are not strictly speaking half-integer spin representations of the Clifford algebra. They instead correspond to a coherent superposition of differential forms. In higher dimensions, particularly on dimensional surfaces, the Dirac–Kähler equation is equivalent to Dirac equations.
In curved spacetime, the Dirac–Kähler equation no longer decomposes into four Dirac equations. Rather it is a modified Dirac equation acquired if the Dirac operator remained the square root of the Laplace operator, a property not shared by the Dirac equation in curved spacetime. This comes at the expense of Lorentz invariance, although these effects are suppressed by powers of the Planck mass. The equation also differs in that its zero modes on a compact manifold are always guaranteed to exist whenever some of the Betti numbers vanish, being given by the harmonic forms, unlike for the Dirac equation which never has zero modes on a manifold with positive curvature.
See also
Fermion doubling
Lattice QCD
References
Theoretical physics
Dirac equation
Lattice field theory
Lev Landau | Dirac–Kähler equation | [
"Physics"
] | 1,232 | [
"Theoretical physics",
"Eponymous equations of physics",
"Equations of physics",
"Dirac equation"
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71,668,690 | https://en.wikipedia.org/wiki/Regulator%20of%20CO%20metabolism | Regulator of CO Metabolism (RcoM) is a heme-containing transcription factor found in bacteria that senses carbon monoxide (CO). In the presence of carbon monoxide, this protein upregulates expression of genes involved in carbon monoxide oxidation or carbon monoxide stress response. RcoM is functionally related to another heme-containing transcription factor, CooA, but RcoM shares no structural relationship with CooA. RcoM is composed of an N-terminal Per-Arnt-Sim (PAS) domain and a C-terminal LytTR domain. The PAS domain binds a single molecule of heme and the LytTR domain binds to DNA upstream of carbon monoxide oxidation genes. The RcoM homolog from Paraburkholderia xenovorans is known to be dimeric and binds heme using a histidine and a methionine ligand in the Fe(II) oxidation state. Carbon monoxide replaces the methionine ligand and binds directly to the heme to active RcoM for DNA binding. Relative to other heme-containing proteins, RcoM has an extraordinarily high CO affinity, with a Kd < 100 pM, allowing this protein to sense very low levels of carbon monoxide.
References
Prokaryote genes
Carbon monoxide
Heme enzymes
Transcription factors | Regulator of CO metabolism | [
"Chemistry",
"Biology"
] | 272 | [
"Protein stubs",
"Gene expression",
"Prokaryotes",
"Signal transduction",
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71,668,824 | https://en.wikipedia.org/wiki/Alzheimer%27s%20disease%20in%20the%20Hispanic/Latino%20population | Alzheimer's disease (AD) in the Hispanic/Latino population is becoming a topic of interest in AD research as Hispanics and Latinos are disproportionately affected by Alzheimer's Disease and underrepresented in clinical research. AD is a neurodegenerative disease, characterized by the presence of amyloid-beta plaques and neurofibrillary tangles, that causes memory loss and cognitive decline in its patients. However, pathology and symptoms have been shown to manifest differently in Hispanic/Latinos, as different neuroinflammatory markers are expressed and cognitive decline is more pronounced. Additionally, there is a large genetic component of AD, with mutations in the amyloid precursor protein (APP), apolipoprotein E APOE), presenilin 1 (PSEN1), bridging Integrator 1 (BIN1), SORL1, and clusterin (CLU) genes increasing one's risk to develop the condition. However, research has shown these high-risk genes have a different effect on Hispanics and Latinos then they do in other racial and ethnic groups. Additionally, this population experiences higher rates of comorbidities, that increase their risk of developing AD. Hispanics and Latinos also face socioeconomic and cultural factors, such as low income and a language barrier, that affect their ability to engage in clinical trials and receive proper care.
Alzheimer's disease
Alzheimer's disease is the most common form of dementia, accounting for 60% of all cases, and is the sixth leading cause of death in the elderly. The disease typically presents itself with intracellular aggregation of hyper-phosphorylated tau, forming neurofibrillary tangles (NFTs), and the extracellular aggregation of amyloid beta (Aβ), forming neuritic plaques. As of 2020, 5.4 million Americans have been diagnosed with Alzheimer's disease, and this number is projected to reach 15-22 million by 2050. Hispanics and Latinos account for 55 million of the population and this population is projected to rise to 97 million, accounting for 25% of the U.S. population, in 2050.
Hispanic/Latino population
Hispanics and Latinos make up 18% of the U.S. population, however, they are underrepresented in clinical research. The National Institute of Health (NIH) reported that Hispanic and Latinos accounted for less than 8% of reported clinical trial participants. One proposed reason for the lack of representation is that the Hispanic/Latino population includes many people from different countries, and with this diverse background come different characteristics and comorbidities associated with AD. Hispanic and Latinos have a higher prevalence of AD compared to White non-Hispanics. Studies estimate that 12% of older Hispanic and Latino adults were diagnosed with AD, the highest proportion compared to all other ethnic groups. Hispanic and Latinos are the fastest-growing population in the U.S., and Hispanic/Latino seniors, those who are 65 and older, are expected to have the largest rise in AD and dementia cases compared to other populations, reaching 3.5 million by 2060. In 2011 the National Alzheimer's Disease Project Act was signed into law. The goal of this act was for The National Institute of Aging to accelerate research and clinical care of patients with AD; this act also has the benefit of seeking to improve the inclusion of underrepresented populations in AD research and clinical trials. It is important to note that this neurodegenerative disease varies across all ethnic groups. Studies show that Latinos are up to one-and-a-half times more likely to develop Alzheimer's than non-Latino whites.
Types
There exist two types of Alzheimer's disease: familial Alzheimer's disease, also called early-onset Alzheimer's disease (EOAD), and sporadic Alzheimer's disease, also called late-onset Alzheimer's disease (LOAD). EOAD is the less common of the two, accounting for 5-10%, and patients with EOAD are typically diagnosed with familial AD before they turn 65 years old. LOAD is more common and accounts for 90% of AD cases and its patients experience onset after they turn 65. EOAD has been shown to have 2 types of inheritance patterns: mendelian (mEOAD) and non-mendelian (nmEOAD, sporadic) patterns. The three main genes that implicated in familial AD are amyloid precursor protein (APP), Presenilin-1 (PSEN-1), presenilin-2 (PSEN-2). Onset of sporadic AD has both genetic and environmental risk factors. Some genes of interest in LOAD are the APOE gene, specifically the ApoE4 allele, bridging Integrator 1 (BIN1), SORL1, and clusterin (CLU).
Pathology and symptoms
Amyloid beta plaques and neurofibrillary tangles
Neuritic plaques and neurofibrillary Tangles (NFTs) are the main pathological component of AD. Neuritic plaques are composed mainly of the peptide Aβ, but also include other components. APP is processed through either of two pathways, the first is termed the amyloidogenic pathway and produces Aβ. The second pathway is the non-amyloidogenic pathway and does not produce Aβ. In the amyloidogenic pathway, APP (the parent protein) is trafficked to endosomes, cleaved by beta-secretase (BACE), after which it moves back to the cell surface to be cleaved by gamma secretase thus releasing the Aβ peptide. This form of APP processing produces multiple Aβ peptides, of which Aβ40 and Aβ42 peptide are most abundantly produced. APP can also be cleaved by alpha and gamma-secretase and undergo non-amyloidogenic processing. NFTs form when the tau protein, which is involved in microtubule stability, is hyperphosphorylated, dissociates from microtubules and then aggregates with other p-tau monomers forming tau oligomers, fibrils and eventually NFTs. These types of pathologies do not differ across ethnic groups.
Chronic inflammation
Neuroinflammation is another pathological component of AD pathology, and is associated with an increase in levels of inflammatory markers. Researchers have also identified many genes linked to immune function that are risk factors for AD, such as TREM2. TREM2 are highly expressed in microglia, the immune cell of the brain, tying the progression of AD with dysfunction in microglial activity. Neuroinflammation, Aβ and tau pathologies interact in Alzheimer's disease, and their progress can be monitored with biomarkers. For example, studies have found the neuroinflammatory marker YKL-40 in the cerebrospinal fluid (CSF) of AD patients. This protein increases years before the onset of AD symptoms and correlates with other neurodegenerative biomarkers, which suggests a potential to predict disease progression. While YKL-40 has not been shown to associate with the APOE -ε4 allele, there is research to link this biomarker to AD in the Hispanic population.
Neurodegeneration
Along with the plaques and inflammation, patients with AD also suffer from neurodegeneration, characterized by loss of neurons and synapses (the communication tool for neurons). As a result, the entire brain shrinks in volume (termed brain atrophy), the ventricles grow larger, and the hippocampus and cortex shrink in size. As all these pathologies progress, patients begin to experience a decline in memory, cognitive abilities, and independence. The accumulation of neurofibrillary tangles and loss of synaptic fields correlate most closely with cognitive loss.
Mild cognitive impairment
Mild cognitive impairment (MCI) precedes the overt diagnosis of AD. To be diagnosed with MCI a patient must show memory impairment, a progressive decline in cognitive abilities without presenting symptoms of Parkinson's disease, cerebrovascular diseases, and behavioral or language disorders. Studies show that older Hispanic/Latinos exhibit a higher prevalence of dementia than caucasians. Demographic and linguistic factors can prevent a proper MCI diagnosis. For instance, subjects for whom English might not be the primary language require use of a translator to perform the cognitive testing, which could affect testing results, but such experimental weaknesses are frequently not described.
Brain imaging
Positron emission tomography (PET) is a brain imaging technique that uses a small amount of radioactive substance, called a tracer, to measure energy use or a specific molecule in different brain regions. In AD research, tracers can be used to detect neuritic plaques (containing Aβ) and tau. Depending on the tracer used, the signal can be used to determine the presence of neuritic plaques and NFTs.
Biomarkers
Establishing biomarkers for the early detection of AD is an ongoing are of research because pathological changes occur years before symptoms become apparent. Common biomarkers for AD include amyloid beta and hyperphosphorylated tau, both of which can be found in brain tissue and cerebrospinal fluid (CSF). Aβ provides a biomarker of neuritic plaques, which form when APP cleavage results in an increase in the Aβ42/Aβ40 ratio. Hyperphosphorylated tau serves as a biomarker of neurofibrillary tangles (NFTs), with the presence of NFTs indicating a disruption in microtubule stability and neuronal injury. Researchers have begun investigating other markers in the CSF, such as markers of neuronal injury, like Visinin-Like-Protein-1 (VILIP-1), YKL-40, and Neurogranin (NGRN). Due to the low use of CSF sampling in most countries, efforts have been made to study biomarkers in blood. Through work on blood biomarkers, researchers have been able to find proteins that are elevated in AD patients and have predictive potential. The predictive potential of these plasma markers increases further when coupled with the presence of genetic risk factors, such as the APOE E4 allele. Examples of plasma biomarkers include interleukin, TGF, and micro-RNA.
Genetic risk factors being considered for integration with biomarkers includes ApoE, PSEN1, Bin1, CLU, and SORL1.
APOE gene
Apolipoprotein E (APOE) is a lipoprotein, composed of 299 amino acids, that is expressed throughout the body but particularly important in the brain where it is involved in cholesterol metabolism, specifically in the intracellular and extracellular transport, delivery, and distribution. APOE associates with high-density lipoproteins (HDL). The gene for APOE is located on chromosome 19 and exhibits polymorphisms in the population defined by three alleles of APOE: 𝜀2, 𝜀3, and 𝜀4. These alleles differ by only two single nucleotide polymorphisms in exon 4, rs429358 and rs7412 (amino-acid position 112 and 158). APOE𝜀3 is the more common of the three and is present in 50-90% of the general population. APOE 𝜀4 is the most common risk factor for LOAD, increasing genetic risk up to 33-fold, depending on the population (see the table below). Over 50% of LOAD patients have the 𝜀4 allele and that having even one copy of the 𝜀4 allele increases the risk of developing Alzheimer's by a factor of 4. APOE 𝜀2 has been shown to have a neuroprotective effect with carriers of the allele showing a lower prevalence of AD. The neuropathological effects of APOE ε4 are pleiotropic; APOE ε4 impairs uptake of cholesterol by neurons, promotes microglial dysfunction, promotes beta-amyloid aggregation and is increases cerebral angiopathy (CAA). The increased incidence of AD associated with the APOE ε4 allele has been proposed to be directly linked to Aβ because it modulates Aβ aggregation and clearance, although increasing evidence points to a multitude of actions.
While extensive research has been done on the APOE4 gene, more information is available for caucasians than for other ethnic and racial groups. The research focusing on the Hispanic and Latino population, suggests that race is a key variable in assessing the risk of carrying the APOE ε4 allele in developing AD. Genetic studies of Hispanic and Latino populations, show a lower risk of developing AD for individuals with the APOE ε4 than observed in Caucasians. For instance, the prevalence of AD seen in Caribbean Hispanics, compared to White Non-Hispanics, appears to be independent of APOE genotype. Our understanding of ApoE ε4 continues to evolve, though, as Hispanic and Latino representation in research increases leading to larger sample sizes and improved population stratification .
PSEN1 gene
Presenilin 1 (PSEN1) is the catalytic subunit of the transmembrane protein complex gamma-secretase. This protein cleaves amyloid precursor protein (APP), after beta-secretase cleavage, to produce Amyloid beta. The gene for PSEN1 is located on chromosome 14, q24.2, and consists of 12 exons that encode a 467-amino-acid protein that is predicted to traverse the membrane 9 times. Over 200 pathogenic mutations of this protein exist, many of which account for 18% to 50% of autosomal dominant EOAD cases. PSEN1 mutations increase the risk of developing AD by increasing the production of amyloid beta-42, compared to amyloid beta-40. Unlike APOE4, PSEN1 mutations tend to have a clear pathological effect in Hispanics and Latinos and tend to express region-specific mutations. Puerto Ricans have a G206A mutation that causes familial AD, Cuban families diagnosed with EAOD commonly exhibit a L174M, mutation, Mexican families exhibit L171P and A431E mutations, and Colombian families exhibit an E280A mutation (particularly in the municipality of Yarumal).
BIN1 gene
Bridging Integrator 1 (BIN1) is a widely expressed Bin-Amphiphysin-Rvs (BAR) adaptor protein that is located on chromosome 2, q14.3, and contains 20 exons. BIN1 mainly regulates clathrin-mediated endocytosis. Due to a large number of exons, this gene is subject to alternative splicing, with the major forms varying in the splicing of exons 6a, 10, 12, and 13. Genetic studies indicate that dysfunction in BIN1 is the second most important risk factor for AD. The mechanism through which BIN1 contributes to AD, though, is unclear. Studies suggest a range of possible reasons that BIN1 is associated with AD including interactions of BIN1 with the microtubule-associated proteins (i.e. CLIP170), endosomal trafficking of APP and APOE by BIN1, and BIN1 mediated regulation of inflammation through the expression of indoleamine 2,3-dioxygenase (IDO1). The interaction of BIN1 and tau might also be important because elevated levels of BIN1 are associated with increased AD risk through tau load; this result is suggested because of studies of the functional rs59335482 variant. Additionally, endocytic trafficking of APP by BIN1 could be important because trafficking determines if APP will undergo the non-amyloidogenic or the amyloidogenic pathway. For example, if APP is transported to the endosome, it will likely be cleaved by beta-secretase and undergo amyloidogenic processing, but if it accumulates on the cell surface it will be likely cleaved by alpha-secretase and undergo non-amyloidogenic processing. Lastly, BIN1 facilitates the kynurenine pathway of tryptophan metabolism by regulating the expression of the rate-limiting enzyme indoleamine 2,3-dioxygenase (IDO1). For the IDO1 mechanism, increased BIN1 expression could increase levels of a toxic tryptophan derivative IDO1. These metabolites have been suggested to be involved in AD pathology and cognitive decline, as they co-localize with the plaques and NFTs in patient brains.
Genome-wide association studies (GWAS) in the Hispanic/Latino population indicate that polymorphisms in the BIN1, ABAC7 and CD2AP genes are more significant in Caribbean Hispanics. For instance, one BIN1 mutation that has been explored in this Caribbean Hispanics is rs13426725. Other variants that increase the risk of AD include rs6733839.
SORL1 gene
Sortilin-related receptor 1 (SORL1) is a 250-kDa membrane protein with seven distinct domains that make it a member of two receptor families: the low-density lipoprotein receptor (LDLR) family of ApoE receptors and the vacuolar protein sorting 10 (VPS10) domain receptor family. In humans, the SORL1 gene is located on chromosome 11, specifically q232-q24.2. As a protein SORL1 is highly expressed in the brain. SORL1 is an intracellular protein that is expressed in early endosomes and the trans-Golgi network. SORL1 plays an important role in the intracellular trafficking of APP. The protein can bind to APP expressed in endosomes and allow APP to be transported back to the cell surface, which prevents amyloidogenic processing and the production of cytotoxic Aβ40 and Aβ42. Moreover, SORL1 has been shown to facilitate cholesterol transport through its tendency to bind to APOE-lipoprotein complexes. Strong disease-linked polymorphisms in SORL1 combine with its role in APP trafficking render SORL1 a biomarker of strong interest for LOAD. Decreased levels of SORL1 transcript and protein have been observed in the brains of AD patients.
Analysis of SORL1 polymorphisms in the Hispanic/Latino population using GWAS and whole-genome sequencing (WGS) have shown that several SORL1 mutations are seen in Caribbean Hispanics. Two rare polymorphisms in SORL1 associated with AD were observed in this population, rs117260922-E270K and rs143571823-T947M, as well as a common variant (rs2298813-A528T) . These polymorphisms are not specific to Hispanics/Latinos as they are also observed in non-Hispanic white individuals.
ATP binding cassette transporters
Adenosine triphosphate (ATP)-binding cassette transporters are a large family of ABC transporters that regulates the efflux of cholesterol in neuronal cells. Two members of the ATP binding cassette transporter family have been implicated in LOAD: ABC Subfamily A Member 1 (ABCA1) and ABC Subfamily A member 7 (ABCA7). ABCA1 is a 220-240 kDa protein whose gene is located in chromosome 9q31.1 Its putative role in AD is tied to its role in stabilizing ApoE lipidation and degrading amyloid beta expressed in the brain. ABCA7 exhibits strong genetic linkage to AD; it is involved in lipid and cholesterol processing, as well as immune system function. ABCA7 exhibits tighter association with amyloid deposition than ABCA1. The research on ABCA7 mutations in the Hispanic/Latino population is a bit controversial. Some studies propose that mutations in ABCA7 are more common in Caucasian patients, whereas Hispanics/Latinos are more likely to express a BIN1 mutation. But researchers have still found polymorphisms specific to this population, one example being a 44-base pair frameshift deletion in ABCA7 increases AD risk in African Americans and Caribbean Hispanics.
Clusterin
Clusterin (CLU), also known as apolipoprotein J, is an 82 kDa glycoprotein protein that is located on chromosome 8. It has multiple physiological functions, some examples being lipid transport, immune modulation, and cell death. CLU is known to have the ability to clear Aβ peptides and prevent their aggregation, which suggests that CLU has a neuroprotective effect. While one might expect AD to be associated with lower levels of a neuroprotective protein, biomarker studies indicate that CLU is upregulated in the plasma, CSF, hippocampus, and cortex of AD patients. One theory explaining this apparent contradiction is CLU is actually reduced early in life, increasing risk of developing AD. In this scenario, CLU might increase in subjects with AD as a compensatory response to the disease; further research is clearly necessary to clairy this area. However, genetic studies show that CLU is the third most significant risk factor for LOAD, which has propelled extensive genetic research related to CLU and AD. Two CLU variants of interest, that are associated with reduced AD frequency, are rs11136000 and rs9331896. However, little is known about the relationship between CLU and AD risk in the Hispanic/Latino community.
Comorbidities
Studies have shown that metabolic disorders, such as diabetes, cardiovascular disease, hypertension, obesity, and depression can increase one's risk of developing AD as well as increase the rate at which it progresses. In the United States, 33% of the total population suffers from a metabolic disorder (i.e. diabetes and hypertension). Hispanic and Latino adults are at an increased risk of developing these conditions compared to Caucasians. As of 2017, it has been reported that 35% of all Latinos suffer from an AD comorbidity, with 17% suffering from diabetes and 25.4% suffering from hypertension. The high prevalence of cardiovascular and metabolic conditions is thought to contribute to the higher risk of Alzheimer's Disease seen in Hispanics and Latinos.
Hypertension
Hypertension is a condition characterized by persistently high blood pressure. Two measurements are taken to quantify blood pressure: systolic and diastolic blood pressure. A patient is diagnosed as hypertensive when their systolic blood pressure is greater than 140 mmHg or diastolic blood pressure is greater than 90 mmHg. Not many people with hypertension are aware that they have the condition. In 2010, 31.1% of adults worldwide had hypertension, but only 45.6% of them were aware they had the condition. Hypertension is more apparent in the Hispanic/Latino population, as in 2008 the incidence rate of hypertension for Hispanic adults aged 45–84 was 65.7%, compared to 56.8% for non-Hispanic whites of the same age. Hispanic/Latinos are more likely to be unaware of their condition, compared to non-Hispanics, and be less likely to seek treatment, which increases the risk of developing cardiovascular disease and AD. Hypertension can be reduced by lifestyle changes (e.g., weight loss and exercise) and pharmacological intervention. Multiple studies suggest that use of antihypertensive drugs might reduce the risk of dementia and AD.
Diabetes
Type-II diabetes is a metabolic condition characterized by high blood sugar and defective insulin secretion by pancreatic β-cells. A patient is diagnosed with diabetes when their fasting blood glucose levels are above 7.0 mmol/L (126 mg/dL) or above 11.1 mmol/L (200 mg/dl) two hours after an oral dose of glucose. As with hypertension, diabetes is more common in the Hispanic/Latino population than in the Caucasian population. In the U.S., Hispanic/Latinos are reported to have a diabetes prevalence of 22.6%, compared to 11.3% in non-Hispanic whites. This increased risk is associated with genetic factors, environmental factors (i.e. diet), and socioeconomic status. Recently AD has also been characterized as a metabolic disease of glucose regulation, as patients experience alterations in brain insulin responsiveness that leads to oxidative stress and inflammation. Changes in cerebral glucose signaling associated with AD have been proposed to as type three diabetes, although this has not been adopted as an official designation. Older diabetic Mexican Americans are twice as likely to develop dementia than those without diabetes. Additionally, the longer a patient is diabetic, the faster the rate of cognitive decline within the same and racial and age group.
Lifestyle
Alzheimer's can change your life rapidly and it involves stripping away a lot of an individual's abilities. The neurons that are damaged first are those involving memory, language, and thinking. Individual's living with this disease may develop changes in mood, personality or behavior and eventually neuronal damage extends to parts of the brain that enable basic bodily functions. Many of the comorbidities for AD can be reduced through lifestyle changes. Hypertension can be treated by reducing sodium intake, increasing potassium intake, reducing alcohol consumption, and engaging in at least 150 min of moderate-intensity or 75 min of vigorous-intensity physical activity per week. Similarly, diabetes can also be treated by increasing physical activity and changing diet. The same lifestyle changes are recommended for AD patients.
Hispanics and Latinos in clinical research
The terms Latino and Hispanic are used interchangeably in formal and informal settings. The term "Hispanic" specifically denotes those who can trace their ancestry to a Spanish-speaking country, such as Spain and most of Latin America, the exceptions being Brazil, Guyana, Suriname, and French Guiana. The term "Latino" denotes those who can trace their ancestry to Latin America and the Caribbean. The diversity among Hispanic and Latino groups has led to proposals that the Latino/Hispanic population in the U.S. should not be treated as a homogenous group, and also to define subgroups based on their country of origin. The Latino/Hispanic community has recently been open to wanting to learn more about Alzheimer's Disease but because of they limited resources they aren't able to participate in clinical research.
Socioeconomic status
The socioeconomic status of the Hispanic/Latino population is thought to contribute to their low participation in clinical trials. In the U.S., the income and socioeconomic status of Hispanics and Latinos are lower when compared to White Non-Hispanics. In 2015, a study reported that 25% of the Hispanic/Latino population lives in poverty and their median family income was $17,800 lower than their white counterparts. The Hispanic/Latino community have grown the understand the affect Alzheimer has had on their community. A need for care was found to have been associated with education level and be a leading contributor to disability among older people. This shows significant implications for the economy and overall burden caregivers have to take on.
Studies from 2017 showed that the difference in income is present across many income brackets, with only 38.6% of Latinos reporting a household income between $50,000 and $149,999, in comparison to 45.6% of Non-Hispanic whites. A similar trend was seen with levels of higher education and medical literacy attained by Hispanics and Latinos. As of 2013, it was reported that 22% of Latino adults (25 years and over) had earned an associate degree or higher, compared to the 46% seen in White Non-Hispanics. This trend is also seen with advanced degrees, as Latinos only account for 7% of Master's degrees and 1% Doctorate degrees awarded in the U.S. The lower measures of socioeconomic achievement and education level have been proposed to be associated with high mortality and dementia rates. In contrast, high educational levels are correlated with lower rates of dementia.
Hispanic and Latinos that are 65 years and older make up one of the largest groups of uninsured individuals in the U.S. This makes it difficult for these seniors to obtain the clinical care necessary for management of AD. The cost of care for insured patients 65 years and older was estimated to be $25,213 per person, compared to the estimated $7750 for senior patients without AD. Increasing efforts are being made to include minorities in clinical research, for instance by providing travel support for participants.
Language barrier
Putative language barriers can also interfere with healthcare for the Hispanic and Latino community. Clinical trials can require participants to be fluent in English, which can potentially exclude older Hispanic and Latino subjects, who might not be fluent in English. Only 40% of the older generation, Latinos over the age of 69, are fluent. Proficiency in English is less of an issue for younger Latinos, with 90% of the population between the ages of 5 and 17 speaking the language fluently. Weak communication between physician and patient can also impair medical care. For instance, this issue occurs with clinical notes, which are typically translated from the English version of the same document for Spanish-speaking individuals. The medical community is attempting to address this issue by recruiting staff and physicians able to communicate with participants in their native language, as well as providing training on cultural sensitivity.
See also
Race and health in the United States
References
External links
National Institute of Aging Summary of its Studies of AD in the Hispanic/Latino Population
Race and health in the United States
Alzheimer's disease research
Gerontology
Cultural studies
Hispanic and Latino American society | Alzheimer's disease in the Hispanic/Latino population | [
"Biology"
] | 6,148 | [
"Gerontology"
] |
71,669,030 | https://en.wikipedia.org/wiki/Rage-baiting | In internet slang, rage-baiting (also rage-farming) is the manipulative tactic of eliciting outrage with the goal of increasing internet traffic, online engagement, revenue and support. Rage baiting or farming can be used as a tool to increase engagement, attract subscribers, followers, and supporters, which can be financially lucrative. Rage baiting and rage farming manipulates users to respond in kind to offensive, inflammatory headlines, memes, tropes, or comments.
Rage-farming, which has been cited since at least January 2022, is an offshoot of rage-baiting where the outrage of the person being provoked is farmed or manipulated into an online engagement by rage-seeding that helps amplify the message of the original content creator. It has also been used as a political tactic at the expense of one's opponent.
Political scientist Jared Wesley of the University of Alberta stated in 2022 that the use of the tactic of rage farming was on the rise with right-wing politicians employing the technique by "promoting conspiracy theories and misinformation." As politicians increase rage farming against their political and ideological opponents, they attract more followers online, some of whom may engage in offline violence, including verbal violence and acts of intimidation. Wesley describes how those engaged in rage farming combine half-truths with "blatant lies".
The wider concept of posting generally provocative content to encourage user interaction is known as engagement farming.
Etymology, definitions and related terms
Rage-farming (or rage-seeding) derives from the concept of "farming" rage; planting metaphorical seeds which cause angry responses to grow. It is a form of clickbait, a term used since c. 1999, which is "more nuanced" and not necessarily seen as a negative tactic. The term rage bait, which has been cited since at least 2009, is a negative form of click-baiting as it relies on manipulating users to respond in kind to offensive, inflammatory "headlines", memes, tropes, or comments.
In his 2022 tweet, a senior researcher at Citizen Lab, John Scott-Railton, described how a person was "being rage-farmed" when they responded to an inflammatory post with an equally inflammatory quote tweet as quote tweets reward the original rage tweet. Algorithms on social media such as Facebook, Twitter, TikTok, Instagram, and YouTube were discovered to reward increased positive and negative engagement by directing traffic to posts and amplifying them.
In an Atlantic article on Republican strategy, American writer Molly Jong-Fast described rage farming as "the product of a perfect storm of fuckery, an unholy mélange of algorithms and anxiety".
Political scientist Jared Wesley wrote that rage farming was often "used to describe rhetoric designed to elicit the rage of opponents." Rage-baiting is used to describe a tactic to attract, maintain, and increase a base of supporters and followers.
Clickbait, in all its iterations, including rage-baiting and farming, is a form of media manipulation, specifically Internet manipulation. While the goal of some clickbait is to generate revenue, it can also be used as effective tactic to influence people on social media platforms, such as Facebook, Twitter, Instagram, and YouTube. According to a November 2016 analysis of Facebook, clickbaits are intentionally designed to a targeted interest group's pre-existing confirmation biases. Facebook's algorithms used a filter bubble that shares specific posts to a filtered audience.
A Westside Seattle Herald article published May 2016 cited the definition from the online Urban Dictionary, "a post on social media by a news organisation designed expressly to outrage as many people as possible in order to generate interaction." The Herald article described how increased user traffic online results equals in more revenue for online platforms and websites from paid advertisements and sponsors.
A May 25, 2016 article described ragebait as "clickbait's evil twin."
A 2006 article in Time magazine described how Internet trolls post incendiary comments online with the sole purpose of provoking an argument even on the most banal topics. A statement like "NASCAR is about as much a sport as cheerleading" in a car-racing forum or openly supporting open borders to Lou Dobbs is cited as an example.
Rage bait and outrage bait creators invent "controversial news stories out of thin air". The example cited was a 15 December 2018 Irish digital media company ad falsely claiming that two thirds of people wanted Santa to be either female or gender neutral.
As early as 2012, research suggested that in both media and politics, eliciting outrage is a powerful tool in media manipulation. In political media, both real and imagined outrage attract readers, making rage-evoking narratives very popular.
Background
A 2012 Journal of Politics (JOP) article found that political actors were intentionally incorporating emotional content to evoke anxiety into their messaging to elicit interest in a topic. The article questioned why this political tactic resulted in viewers feeling more anger than anxiety. The study found that anger increased information-seeking behaviour and often resulted in web users clicking on the political website to learn more. The research said there were also psychological incentives to use angry rhetoric in political communication. A 2018 Media Matters for America article citing the JOP journal, reiterated that "anger is a powerful tool in the worlds of both politics and media." The political media industry knows that real or imagined outrage attracts readers making narratives that evoke it very popular in political media.
A November 2018 National Review article decrying social-justice warriors was cited as an example of rage-baiting by Media Matters for America. The Review article was in response to Tweets criticizing the cartoon image used by the ABC's Twitter account to advertise A Charlie Brown Thanksgiving on November 21, 2018. Franklin, the Black friend was sitting all alone on one side of Charlie Brown's Thanksgiving dinner table. Several unverified accounts by Twitter users, including one with zero followers, called the image racist. Conservatives were so frustrated by these overly sensitive, politically correct, "snowflake" liberals who posted, that they in turn responded in anger. The Media Matters for America article said that there was irony in the way in which the National Review article which intended to illustrate how liberals were too easily provoked to anger, actually succeeded in enraging conservatives.
Information technologies and digital media enable unprecedented capacities for online manipulation, including click-baiting, rage baiting and rage farming. In his January 7, 2022 tweet, John Scott-Railton described how a person was "being rage farmed" when they responded to an inflammatory post with an equally inflammatory quote tweet since algorithms on Twitter, TikTok, YouTube, Facebook and other social media platforms, reward posts that attract engagement by amplifying the posts.
A 2020 review of the conservative Canadian online news magazine, The Post Millennial, which was started in 2017, said it was far-right America's most recent rage-baiting outlet.
Examples of rage farming
Social media
Rage farming and rage baiting are most recent iterations of clickbait and other forms of Internet manipulation that use conspiracy theories and misinformation to fuel anger and engage users. Facebook has been "blamed for fanning sectarian hatred, steering users toward extremism and conspiracy theories, and incentivizing politicians to take more divisive stands," according to a 2021 Washington Post report. In spite of previous reports on changes to its News Feed algorithms to reduce clickbait, revelations by Facebook whistleblower Frances Haugen and content from the 2021 Facebook leak, informally referred to as the Facebook Papers, provide evidence of the role the company's News Feed algorithm had played.
Media and governmental investigations in the wake of revelations from Facebook whistleblower, Frances Haugen, and the 2021 Facebook leak, provide insight into the role various algorithms play in farming outrage for profit by spreading divisiveness, conspiracy theories and sectarian hatred that can allegedly contribute to real-world violence. A highly criticized example was when Facebook, with over 25 million accounts in Myanmar, neglected to police rage-inducing hate speech posts targeting the Rohingya Muslim minority in Myanmar that allegedly facilitated the Rohingya genocide. In 2021, a billion class action lawsuit filed against Meta Platforms Inc (the new name of Facebook) on behalf of Rohingya refugees claimed that Facebook's "algorithms amplified hate speech."
In response to complaints about clickbait on Facebook's News Feed and News Feed ranking algorithm, in 2014 and again in 2016, the company introduced an anti-clickbait algorithm to remove sites from their News Feed that frequently use headlines that "withhold, exaggerate or distort information."
A February 2019 article that was promoted in Facebook described how outrage bait made people angry "on purpose". Digital media companies and social media actors incite outrage to increase engagement; "clicks, comments, likes and shares", which generate "more advertising revenue". If content does not increase engagement, "timeline algorithm" limits the number of users that this uninteresting content can reach. According to this article, when geared up on its war against clickbait, algorithm changed, which made it harder for creators and sites to use clickbait. The article said that a new engagement strategy was introduced to replace clickbait, whether rage bait or outrage bait.
The 2016 algorithms were allegedly trained to filter phrases that were frequently used in clickbait headlines similar to filters that remove email spam. Publishers who continue to use clickbait were allegedly punished through loss of referral traffic.
Starting in 2017, Facebook engineers changed their ranking algorithm to score emoji reactions five times higher than mere "likes" because emojis extended user engagement, according to a 26 October 2021 Washington Post article. Facebook's business model depended on keeping and increasing user engagement. One of Facebook's researchers raised concerns that the algorithms that rewarded "controversial" posts including those that incited outrage, could inadvertently result in more spam, abuse, and clickbait.
Since 2018, Facebook executives had been warned in a slide presentation that their algorithms promoted divisiveness but they refused to act. In a 2022 interview Scott-Railton had observed that the amplification by algorithms of these inflammatory quote tweets in rage farming that looped upon themselves may have been planned and structural or accidental. Algorithms reward positive and negative engagement. This creates a "genuine dilemma for everyone". Algorithms also allow politicians to bypass legacy media outlets that fact-check, by giving them access to a targeted uncritical audience who are very receptive of their messaging, even when it is misinformation.
By 2019, Facebook's data scientists confirmed that posts that incited the angry emoji were "disproportionately likely to include misinformation, toxicity and low-quality news."
The 2020 Netflix docudrama The Social Dilemma analyzed how social media was intentionally designed for profit maximization through Internet manipulation which can include spreading conspiracy theories and disinformation and promoting problematic social media use. Topics covered in the film included the role of social media in political polarization in the United States, political radicalization, including online youth radicalization, the spread of fake news and as a propaganda tool used by political parties and governmental bodies. Social media networks have three main goals: to maintain and increase engagement, growth, and advertisement income, according to a former Google design ethicist.
A 2024 Rolling Stone article discusses the rise of "rage-bait" influencers on TikTok who create content designed to provoke anger and generate engagement. Influencers such as Winta Zesu and Louise Melcher produce staged, controversial videos that often go viral across multiple platforms, drawing in viewers who may not realize the content is fabricated.
Facebook outside the United States
A 2021 report by The Washington Post revealed that Facebook did not adequately police its service outside the United States. The company invested only 16% of its budget in fighting misinformation and hate speech in countries outside the United States, such as France, Italy, and India where English is not the maternal language. In contrast, the company allocated 84% to the United States which only represents 10% of Facebook's daily users.
Since at least 2019, Facebook employees were aware of how "vulnerable these countries, like India, were to "abuse by bad actors and authoritarian regimes" but did nothing to block accounts that published hate speech and incited violence. In their 2019 434-page report submitted to the Office of the United Nations High Commissioner for Human Rights on the findings of the Independent International Fact-Finding Mission on Myanmar, the role of social media in disseminating hate speech and inciting violence in the anti-Muslim riots and the Rohingya genocide was investigated. Facebook was mentioned 289 times in the report as there are millions of Facebook accounts in that country. Following the publication of an earlier version of the report in August, Facebook took the "rare step" of removing accounts that represented 12 million followers implicated in the reports findings.
In October 2021, Haugen testified at a United States Senate committee that Facebook had been inciting ethnic violence in Myanmar which has over 25 million Facebook users, and in Ethiopia through its algorithms that promoted posts inciting or glorifying violence. False claims about Muslims stockpiling weapons were not removed.
The Digital Services Act is a European legislative proposal to strengthen rules on fighting disinformation and harmful content, that was submitted by the European Commission to the European Parliament and the Council of the European Union partially in response to concerns raised by the Facebook Files and revelations in Haugen's testimony in the European Parliament. In 2021, a c$. US 173 billion dollar class action lawsuit was lodged by law firms Edelson PC and Fields PLLC against Meta Platforms Inc, formerly known as Facebook in the United States District Court for the Northern District of California on behalf of Rohinga refugees, claiming that Facebook was negligent in not removing inflammatory posts that facilitated the Rohingya genocide in Myanmar. The lawsuit said that Facebook's "algorithms amplified hate speech."
Following its launch in Myanmar in 2011, Facebook "quickly became ubiquitous." A report commissioned by Facebook led to the company's admission in 2018, that they had failed to do "enough to prevent the incitement of violence and hate speech against the [...]Muslim minority in Myanmar." The independent report found that "Facebook has become a means for those seeking to spread hate and cause harm, and posts have been linked to offline violence".
See also
Griefer
Hot take
Outrage porn
Outrage industrial complex
Sealioning
Sensationalism
References
Sources
Thirty-ninth session 10–28 September 2018 Agenda item 4
External links
Internet slang
Political campaign techniques
Advertising techniques
Anti-social behaviour
Propaganda techniques
Rhetoric
Informal fallacies
Deception
Internet terminology
Internet trolling
Technology neologisms
Media bias
Media manipulation
News media manipulation
Pejorative terms related to technology | Rage-baiting | [
"Technology",
"Biology"
] | 3,065 | [
"Computing terminology",
"Behavior",
"Internet terminology",
"Anti-social behaviour",
"Human behavior"
] |
71,672,297 | https://en.wikipedia.org/wiki/List%20of%20garden%20cities | The localities in the following lists have been developed directly as garden cities or their development has been heavily influenced by the garden city movement. Detailed information is collected and provided by World Garden Cities, a knowledge platform created by Museum Het Schip in Amsterdam, the Netherlands.
Africa
Morocco
Ifrane
South Africa
Edgemead, Milnerton
Pinehurst, Durbanville
Pinelands, Cape Town
Asia
Armenia
Kentron District, Yerevan
Hong Kong
Kowloon Tong, New Kowloon
Sha Tin, the New Territories
Indonesia
Menteng, Jakarta
Kebayoran Baru, Jakarta
North Bandung, West Java
Israel
Tel Aviv
Japan
Den-en-chōfu, Ōta, Tokyo
Pakistan
Model Town, Lahore
Russia
Akademgorodok, Novosibirsk, Novosibirsk Oblast
Singapore
Singapore
Vietnam
Da Lat
Europe
Czechia
Zlín
Finland
Käpylä
Kauniainen
Tapiola
France
Garden City, Suresnes, designed by Alexandre Maistrasse, Julien Quoniam, and Félix Dumail
Garden City , Stains, designed by Eugène Gonnot and Georges Albenque
Garden City , Pré-Saint-Gervais, designed by Félix Dumail
Germany
Frohnau, Berlin
Gartenstadt , Mannheim
Hellerau, Dresden
Hungary
Wekerle estate, Budapest
Ireland
Marino, Dublin
Italy
Città Giardino Aniene (later Monte Sacro), Rome
Garbatella, Rome
Latvia
Mežaparks, Riga
Lithuania
Žaliakalnis, Kaunas
Netherlands
Tuindorp Vreewijk, Rotterdam
Tuindorp 't Lansink, Hengelo
Tuindorp Oostzaan, Amsterdam
Tuindorp Watergraafsmeer, Amsterdam
Norway
Ullevål Hageby
Poland
Giszowiec, Katowice
Jelonki, Warsaw
Konstancin-Jeziorna
Milanówek
Młociny, Warsaw
Podkowa Leśna
Radom
Sępolno, Wrocław
Służew, Warsaw
Portugal
Encarnação, Lisbon
Russia
Zelenograd, Moscow
Slovakia
Svit
Slovenia
Velenje
Spain
Covaresa, Valladolid
United Kingdom
England
Bedford Park, London
Bournville Village, Birmingham
Brentham Garden Suburb, London
Hampstead Garden Suburb, London
Letchworth Garden City, Hertfordshire
Manor, Sheffield, South Yorkshire
Moor Pool, Birmingham
Milton Keynes, Buckinghamshire
Penkhull Garden Village, Stoke-on-Trent
St Helier, London
Telford, Shropshire
The Garden Village, Kingston upon Hull, Yorkshire
Welwyn Garden City, Hertfordshire
Wythenshawe, Manchester
Scotland
Glenrothes, Fife
Rosyth, Fife
Wales
Glyn Cory Garden Village (now Wyndham Park), Vale of Glamorgan
Kinmel Bay, Conwy
North America
Canada
Grand Falls-Windsor, Newfoundland and Labrador (1905)
Prince Rupert, British Columbia (1910)
Town of Mount Royal, Quebec (1912)
Gardenvale Neighbourhood, Sainte-Anne-de-Bellevue, Quebec, (ca. 1918)
Kapuskasing, Ontario (1921)
Corner Brook, Newfoundland and Labrador (1923)
Cité-jardin du Tricentenaire (Tricentennial Garden-City), Montreal, Quebec (1940–1947),
Kitimat, British Columbia (1951)
United States
Augusta, Georgia (1900)
Forest Hills, Queens, New York City, New York (start date 1908)
Jackson Heights, New York City
Forest Hills, Boston (1911)
Park Circle, North Charleston, South Carolina (ca. 1912)
Narbrook Park, Narberth, Pennsylvania (c. 1915)
Fairview, Camden, New Jersey (1918)
Mariemont, Ohio (1923)
Sunnyside Gardens Historic District, Queens, New York City, New York (1920s)
Radburn, New Jersey (1929)
Three New Deal Greenbelt communities:
Greenbelt, Maryland (1935)
Greenhills, Ohio (1930s)
Greendale, Wisconsin (1936)
Chatham Village, Pittsburgh, Pennsylvania (1930s)
Wyvernwood Garden Apartments, Los Angeles, California (1939)
Wilshire Village, Houston, Texas (1940, demolished 2009)
Baldwin Hills Village, Los Angeles, California (1941)
Epcot, Bay Lake, Florida (1960s)
Village Homes, Davis, California (1960s)
Reston, Virginia (1964)
Paloma Del Sol, Temecula, California (1992)
Oceania
Australia
Haberfield, New South Wales, Sydney, New South Wales (1901)
Daceyville (Dacey Garden Suburb), New South Wales, Sydney, New South Wales (1912)
Rosebery, Sydney, New South Wales (1912)
Colonel Light Gardens, Adelaide, South Australia (1915)
Garden City, Victoria, in inner bayside Melbourne, Victoria (1926)
Peter Lalor Housing Estate, Lalor, Victoria
The Sunshine Estate, Sunshine, Victoria
Canberra, the Australian Capital Territory (1913)
Wundowie, Western Australia (1947)
New Zealand
Christchurch, Canterbury
South America
Argentina
Ciudad Jardín Lomas del Palomar, Buenos Aires
Brazil
Cianorte
Goiânia
Jardins, São Paulo
Maringá
Chile
Providencia
Viña del Mar
References
Planned communities
Sustainable urban planning
Urban forestry
1898 introductions
Architecture related to utopias | List of garden cities | [
"Engineering"
] | 1,047 | [
"Architecture related to utopias",
"Architecture"
] |
71,672,474 | https://en.wikipedia.org/wiki/WISEA%201810%E2%88%921010 | WISEA J181006.18-101000.5 or WISEA 1810-1010 is a substellar object in the constellation Serpens about 8.9 parsec or 29 light-years distant from earth. It stands out because of its peculiar colors matching both L-type and T-type objects, likely due to its very low metallicity. Together with WISEA 0414−5854 it is the first discovered extreme subdwarf (esd) of spectral type T. Lodieu et al. describe WISEA 1810-1010 as a water vapor dwarf due to its atmosphere being dominated by hydrogen and water vapor.
Discovery
WISEA 1810-1010 was first identified with the NEOWISE proper motion survey in 2016, but the proper motion could not be confirmed because of the high density of background stars in this field near the galactic plane. In 2020 the object was re-examined with the WiseView tool by the researchers of the Backyard Worlds project and was found to have significant proper motion. Additionally the object was independently discovered by the citizen scientist Arttu Sainio via the Backyard Worlds project.
Observations
The object was initially observed by the Backyard Worlds researchers from US and Canada with Keck/NIRES and Palomar/TripleSpec. Later it was observed by another team from Spain, UK and Poland with NOT/ALFOSC, GTC/multiple instruments and Calar Alto/Omega2000.
Analysis of the Keck and Palomar spectrum found that WISEA 1810-1010 has much deeper 1.15 μm (Y/J-band) absorption when compared to the extreme subdwarf of spectral type L7 2MASS 0532+8246, but the shape of the H-band is similar to this esdL7. The Y- and J-band spectrum does match better with spectra from subdwarfs with early spectral type T.
Distance and physical properties
The distance was first poorly constrained at either 14 or 67 parsec, but using archived and new data the parallax was measured, which constrained the distance to .
The object has a mass of , which makes this object a brown dwarf or a sub-brown dwarf, with a temperature of 700 to 900 K. A spectral type of esdT3: was estimated based on a new work that introduced a new classification scheme for cold subdwarfs. The prefix esd stands for "extreme subdwarfs" and the double point stands for a highly uncertain numerical spectral type. Best-fitted SAND models find a temperature and radius similar to the previous estimate by Lodieu et al. The motion of WISEA 1810-1010 was used to predict a 91% probability of thin disk membership and a 9% probability of thick disk membership. It is however noted that high probability of thin disk membership, does not rule out thick disk membership.
Atmosphere
The only chemicals detected in the atmosphere of WISEA 1810-1010 are hydrogen and strong absorption due to water vapor. This is surprising because T-dwarfs are defined by methane in their atmosphere and the hotter L-dwarfs are partly defined by carbon monoxide in their atmosphere. Both are missing in WISEA 1810-1010. The missing of carbon monoxide and methane can be explained by a carbon-deficient and metal-poor atmosphere. Alternatively the spectrum could be explained by an oxygen-enhanced atmosphere.
Model spectra suggest a very metal-poor atmosphere with .
Spectral type
Schneider et al. noted first the similarities of the spectrum with both L-dwarfs and T-dwarfs. The tentative classification as esdT0.0±1.0 was given due to the low estimated temperature. The discovery by Lodieu et al. that methane was not present in the near-infrared spectrum raised the question if a T-dwarf classification was possible. Methane is a key diagnostic feature for T-dwarfs. Jun-Yan Zhang et al. noted that WISEA 1810 cannot be classified as an L-dwarf either because of some key differences, such as:
A redder W1-W2 color.
Missing hydrides (such as FeH), which become stronger in metal-poor L-dwarfs.
L-subdwarfs have little water absorptions, but WISEA 1810 has deep water absorptions
JWST observations of the methane band and other molecules in the mid-infrared of WISEA 1810 or other proposed esdT might resolve the question if these objects can be classified as T-dwarfs. If these objects cannot be classified as T-dwarfs, they might be given a new spectral type. Jun-Yan Zhang et al. proposed the letters H or Z (therefore H-dwarf or Z-dwarf). New esdT (or H/Z-dwarfs) might be discovered in the future with ESA's Euclid and the Rubin Observatory.
See also
2MASSI J0937347+293142 first subdwarf of spectral type T
WISE 1534–1043 likely first subdwarf of spectral type Y
List of star systems within 25–30 light-years
References
Brown dwarfs
Serpens
Subdwarfs | WISEA 1810−1010 | [
"Astronomy"
] | 1,044 | [
"Constellations",
"Serpens"
] |
71,672,577 | https://en.wikipedia.org/wiki/Page%20Analysis%20and%20Ground%20Truth%20Elements | Page Analysis and Ground Truth Elements (PAGE) is an XML standard for encoding digitised documents. Comparable to ALTO (XML), it allows the organisation and structure of a page and its contents to be described.
PAGE XML can be used to describe:
page content (regions, lines of text, words, glyphs, reading order, text content, ...)
the evaluation of the layout analysis (evaluation profiles, evaluation results, ...)
the cutting of the document image (cutting grids)
The format is developed by the Pattern Recognition & Image Analysis Lab (PRIMA) at the University of Salford in Manchester.
It was designed to be used in conjunction with automatic segmentation and transcription techniques (OCR and HTR): indeed, PAGE aims to support each of the different steps in the processing chain for image document analysis (from image enhancement to layout analysis to OCR).
The PAGE XML schema is notably used as an export and import format by automatic transcription software such as eScriptorium and Transkribus. It is also an export format used by Kraken, a turnkey OCR system optimised for documents in historical and non-Latin scripts.
References
External links
Documentation
Encoding example
Documentation of the PAGE XML Format for Page Content in the OCR-D project, funded by Deutsche Forschungsgemeinschaft.
Documentation "Page Content - Ground Truth and Storage"
Documentation "Evaluation - Metadata, Profile and Results"
Documentation "Dewarping - Ground Truth and Storage"
XML-based standards
Optical character recognition
Handwriting recognition | Page Analysis and Ground Truth Elements | [
"Technology"
] | 317 | [
"Computer standards",
"XML-based standards"
] |
62,999,435 | https://en.wikipedia.org/wiki/Mihaela%20Ignatova | Mihaela Ignatova is a Bulgarian mathematician who won the 2020 Sadosky Prize of the Association for Women in Mathematics for her research in mathematical analysis, and in particular in partial differential equations and fluid dynamics.
Education
In 2004, Ignatova earned both a bachelor's degree from Sofia University and a master's degree from the University of Nantes. She earned a second master's degree from Sofia University in 2006, working under the supervision of mathematician Emil Horozov. She then completed PhD studies from University of Southern California in 2011 under the supervision of Igor Kukavica.
Career
After working as a visiting assistant professor at the University of California, Riverside, a postdoctoral researcher at Stanford University, and an instructor at Princeton University, she moved to Temple University as an assistant professor in 2018.
References
External links
Home page
Year of birth missing (living people)
Living people
21st-century Bulgarian mathematicians
Bulgarian women mathematicians
Mathematical analysts
Sofia University alumni
University of Nantes alumni
University of Southern California alumni
Temple University faculty | Mihaela Ignatova | [
"Mathematics"
] | 204 | [
"Mathematical analysis",
"Mathematical analysts"
] |
62,999,606 | https://en.wikipedia.org/wiki/Ima%20Market | The Ima Market (; literally, Mothers' Market), also known as the Nupi Keithel () or the Khwairamband Keithel (), is a women-only market in the middle of Imphal in the Indian state of Manipur. It is the only market in the world run entirely by women. Inside the market, male shopkeepers and vendors are not allowed to sell anything. The Government of Manipur has announced that the male shopkeepers and vendors will be punished if their shops and vendors are found inside the market. It is a commercial center and a popular tourist attraction in the state of Manipur. It was established in the 16th century and hosts around 5,000–6,000 women vendors who sell a variety of products. Products such as vegetables, fruits, textiles, toys, fish, spices and utensils are available in the market. It is the largest all–women market in Asia.
History
The market was established in the 16th century following the imposition of the labour system, lallup-kaba in 1533 CE. The lallup-kaba was a forced labour system in Manipur Kingdom which required male members of the Meitei ethnicity to work in distant lands or to serve in the army. As a consequence of the system, women had to support their households by cultivating their fields or weaving textiles and then selling the products on improvised markets. The improvised markets led to the formation of the organized Ima Keithel. The Ima Keithel was the primary permanent market in Manipur until the 20th century.
In 1891, the British colonial administration attempted to impose economic and political reform in Manipur Kingdom, which disrupted the functioning of the market. The reforms involved large scale seizure and export of food corps from Manipur without consideration for local requirements which caused starvation at times of Mautam. It led to agitations by the women of the Ima Keithel and in response, the British attempted to sell off the assets and properties of Ima Keithel to foreigners and external buyers. This, among other causes, resulted in the Nupi Lan or the women's war, which eventually seized with the Japanese invasion of India.
Following independence, the market regained prominence as a commercial center and a hub of socio-political discussions. In 2010, the market was moved into the Khawairamband Bazaar complex constructed by the Municipal Corporation of Imphal. The complex had sustained damaged in the 2016 Imphal earthquake, which effected the livelihood of around 800 vendors.
Market
The Ima Keithel is located in the Khawairamband Bazaar Complex reconstructed on the site of Purana Bazaar in central Imphal. It is located west of Kangla Fort and on the Bir Tikendrajit Road in the Thangal Bazar locality. The complex consists of three large buildings with pagoda styled roofs. The market is split into two sections on either side of the road. Two buildings are located to the north of the main road and one to the south. Leimarel Shidabi Ima, or Purana Bazar, is the oldest and largest structure in the complex and Emoinu Ima Keithel, or Laxmi Bazar is the smallest structure in the complex, both are located to the north of main road. Phouoibi Ima Keithel, or the New Market, mainly sells handloom items, especially Meitei traditional clothes, that includes various phaneks, sarees, and inaphi, is located to the south of the road. The buildings are segregated into textile housing sections and household groceries sections. There is also a section of stalls under a large tin and tarp arrangement market to the east of the main buildings. In order to set up stalls in the main buildings of the market, an annual municipal fees is levied. The fee of a stall was ₹140,000 per annum at the time of construction in 2010. There is a licensing system in place for vendors with stalls. The market houses around 5000–6000 women vendors at any given day. As of 2017, the vendors at the market make an annual profit between ₹73,000 and ₹200,000. The annual turnover of the market was estimated to be between ₹40–50Crore.
Management
The market is managed by a union of all the vendors of the market. It maintains a custom of only allowing women who have been married at least once to set up stalls. The women vendors include those who are divorced or have been widowed in the insurgency in Manipur. To be able to sell in the market, a new woman vendor needs to be referred by a retiring vendor. The vendors are primarily in the age of 45–70 years. The union also runs a credit system for lending to women traders.
Currently, Ima Ibeyaima. K and Ima Th.Angela are the convenors of Khwairamband Ima Keithel Joint Coordinating Committee for Peace. Asem Nirmala is the General Secretary of Khwairamband Ima Keithel Lukmai Sellup.
Compliments
Minister of External Affairs of India, S Jaishankar called Ima market a "great example of nari shakti (women's power) powering economic growth."
In February 2023, delegates of B20 from the G20 forum visited the Ima Market. One of the delegates said, "I will tell the world that there is a beautiful market run by women that sells authentic handicrafts, clothes and others."
See also
Meira Paibi
References
Meitei architecture
Meitei culture
16th-century establishments in India
Markets in India
Retail markets in India
Bazaars in India
Shopping districts and streets in India
History of Manipur
Organisations based in Manipur
Tourist attractions in Manipur
Imphal
Women in Meitei culture | Ima Market | [
"Engineering"
] | 1,186 | [
"Meitei architecture",
"Architecture"
] |
63,001,447 | https://en.wikipedia.org/wiki/Peregrina%20Quintela%20Est%C3%A9vez | Peregrina Quintela Estévez (born 1960) is a Spanish applied mathematician. She is a professor of applied mathematics at the University of Santiago de Compostela, the founding director of the Spanish Network for Mathematics and Industry, and the winner of the 2016 María Josefa Wonenburger Planells prize of the Galician government.
Education and career
Quintela earned a bachelor's degree in mathematics from the University of Santiago de Compostela in 1982, a PhD from the Autonomous University of Madrid in 1986, and a second doctorate from the University of Paris in 1988. Her 1988 dissertation, Sur Quelques Question D'elasticité Non Linéaire et de Théorie de Plaques [On Some Questions of Nonlinear Elasticity and Plate Theory] was supervised by Philippe G. Ciarlet.
She has been chair of the Spanish Network for Mathematics and Industry since it was founded in 2011. She is also director of the Technological Institute for Industrial Mathematics (ITMATI), founded in 2013.
Books
With four co-authors, Quintela wrote the book TransMath: Innovative Solutions from Mathematical Technology (Springer, 2012) on technology transfer in mathematics. She is also the author of two books on MATLAB published through her university, and of two Spanish-language textbooks on differential equations and on numerical methods in engineering, published by Tórculo Ediciones in 2000 and 2001, as well as the editor of several conference proceedings.
Recognition
In 2016, the Government of Galicia gave Quintela their María Josefa Wonenburger Planells prize, given "to highlight the outstanding careers of women in the field of science and technology".
References
Further reading
(interview)
(interview)
External links
Home page
1960 births
Living people
20th-century Spanish mathematicians
Spanish women mathematicians
Applied mathematicians
University of Santiago de Compostela alumni
Autonomous University of Madrid alumni
Academic staff of the University of Santiago de Compostela
21st-century Spanish mathematicians | Peregrina Quintela Estévez | [
"Mathematics"
] | 388 | [
"Applied mathematics",
"Applied mathematicians"
] |
63,002,132 | https://en.wikipedia.org/wiki/Pimodivir | Pimodivir (VX-787, JNJ-63623872) is an antiviral drug which was developed as a treatment for influenza. It acts as an inhibitor of influenza virus polymerase basic protein 2, and has shown promising results in Phase II clinical trials. However, in late 2021, Janssen announced that the clinical development of pimidivir had been halted due to lack of benefit over standard of care.
See also
Baloxavir marboxil
Favipiravir
Galidesivir
Nitazoxanide
Oseltamivir
Peramivir
Remdesivir
Ribavirin
Triazavirin
Umifenovir
Zanamivir
References
Anti–RNA virus drugs
Antiviral drugs | Pimodivir | [
"Biology"
] | 155 | [
"Antiviral drugs",
"Biocides"
] |
63,002,278 | https://en.wikipedia.org/wiki/Presatovir | Presatovir (GS-5806) is an antiviral drug which was developed as a treatment for respiratory syncytial virus. It acts as a fusion inhibitor, and has shown promising results in Phase II clinical trials.
See also
Palivizumab
Lumicitabine
Ziresovir
References
Anti–RNA virus drugs
Antiviral drugs | Presatovir | [
"Biology"
] | 74 | [
"Antiviral drugs",
"Biocides"
] |
63,002,530 | https://en.wikipedia.org/wiki/Post%20common%20envelope%20binary | A post-common envelope binary (PCEB) or pre-cataclysmic variable is a binary system consisting of a white dwarf or hot subdwarf and a main-sequence star or a brown dwarf. The star or brown dwarf shared a common envelope with the white dwarf progenitor in the red giant phase. In this scenario the star or brown dwarf loses angular momentum as it orbits within the envelope, eventually leaving a main-sequence star and white dwarf in a short-period orbit. A PCEB will continue to lose angular momentum via magnetic braking and gravitational waves and will eventually begin mass-transfer, resulting in a cataclysmic variable. While there are thousands of PCEBs known, there are only a few eclipsing PCEBs, also called ePCEBs. Even more rare are PCEBs with a brown dwarf as the secondary. A brown dwarf with a mass lower than 20 might evaporate during the common envelope phase and therefore the secondary is supposed to have a mass higher than 20 .
The material ejected from the common envelope forms a planetary nebula. One in five planetary nebulae are ejected from common envelopes, but this might be an underestimate. A planetary nebula formed by a common envelope system usually shows a bipolar structure.
The suspected PCEB HD 101584 is surrounded by a complex nebula. During the common envelope phase the red giant phase of the primary was terminated prematurely, avoiding a stellar merger. The remaining hydrogen envelope of HD 101584 was ejected during the interaction between the red giant and the companion and it now forms the circumstellar medium around the binary.
Many eclipsing post-common envelope binaries show variations in the timing of eclipses, the cause of which is uncertain. While orbiting exoplanets are often proposed as the cause of these variations, planetary models often fail to predict subsequent changes in eclipse timing. Other proposed causes, such as the Applegate mechanism, often cannot fully explain the observed eclipse timing variations either.
List of post-common envelope binaries
Sorted by increasing orbital period.
See also
Cataclysmic variable
References
Binary stars
White dwarfs
Stellar phenomena | Post common envelope binary | [
"Physics"
] | 438 | [
"Physical phenomena",
"Stellar phenomena"
] |
63,003,328 | https://en.wikipedia.org/wiki/Qilin%20Li | Qilin Li is a Chinese environmental engineer who is a professor of Civil and Environmental Engineering at Rice University. She develops new technologies to analyze and treat contaminated water. Li is a Fellow of the International Water Association.
Early life and education
Li is from China. She earned her undergraduate degree at Tsinghua University. She moved to the United States for her graduate studies, joining the University of Illinois at Urbana–Champaign as a doctoral student. She worked on membrane filtration systems with Vernon Snoeyink. After completing her PhD Li moved to Yale University, where she worked as a postdoctoral fellow.
Research and career
Li studies water contamination and treatment. She joined the faculty at Rice University in 2006. The research of the Li laboratory for Advanced Water Treatment Technologies includes analysis of how membranes become fouled during filtration, how to remove salt from seawater and how to use nanotechnology to clean water.
She is the Associate Director of the Center for Nanotechnology Enabled Water Treatment (NEWT). Here she was awarded a $1.7 million United States Department of Energy grant to develop new technologies that make use of sunlight and nanoparticles to treat water. Li created the Nanophotonics Enabled Solar Membrane Distillation (NESMD), which combines a traditional porous membrane with low-cost light-capturing nanoparticles. Membrane distillation is cheap and can be operated in low temperature, low pressure environments. In NESMD, highly localized solar illumination and photothermal heating drives the process of membrane distillation. She was elected Fellow of the International Water Association in 2018. At the 2019 American Water Summit Li and her NESMD devices were awarded first place in the Tech Idol competition.
In 2019 Li was awarded one of Rice University's InterDisciplinary Excellence Awards, using which she combined resource management and efforts to encourage more sustainable resource consumption on the Rice campus. Li serves as Co-Chair of the International Water Association Nano & Water Specialty Group.
Selected publications
References
External links
Living people
Tsinghua University alumni
Grainger College of Engineering alumni
Rice University faculty
Water treatment
Year of birth missing (living people) | Qilin Li | [
"Chemistry",
"Engineering",
"Environmental_science"
] | 429 | [
"Water treatment",
"Water pollution",
"Water technology",
"Environmental engineering"
] |
63,004,023 | https://en.wikipedia.org/wiki/EEBUS | EEBUS () is a protocol suite for the Internet of things that aims to standardize the interface between electrical consumers, producers, storages, and (logical) managing entities. It builds on the Internet Protocol and related standards and is meant to be highly generic, cross-domain applicable, open, and free to the public. While its main area of application is the Energy demand management, data exchange, and control of appliances it is also specified for Home automation. A business logic is not specified by EEBUS. The EEBus Initiative e.V. is the non-profit association that manages and supports the standardization of EEBUS.
History
EEBUS was developed in response to the growing number of domain-specific (bus) protocols that made an integration of physical devices into larger systems challenging. As a consequence of the complexity and diversity of individual approaches, the design of integrated systems was, at that time, achieved by proprietary solutions. With the global trends of electrification and Energy transition, the need for better system integration of electrical consumers from all industries was perceived an important goal and thus analyzed in the E-Energy research project Smart Watts consequently, manufacturers from the following domains started to collaborate to standardize interfaces:
White goods
Heating, ventilation, and air conditioning (HVAC)
Photovoltaic (and battery) inverters
Electric vehicles and electric vehicle supply equipment (EVSE, e.g. wall-mounted domestic charging stations)
Structure of EEBUS
The protocol stack is composed of two protocols. On the OSI model's transport layer, the so called Smart Home IP is used, while the higher-layer functionality is subsumed as SPINE (Smart Premises Interoperable Neutral Message Exchange).
High-level use cases that allow the implementation of a business logic for a company make use of the EEBUS SPINE specification.
Since 2016, all released documents are available free of charge on the website of EEBus Initiative e.V. after a free registration: Media & Downloads
The specification of the lower ISO/OSI layers and the specification for the application layer are fully released.
Standardization
The standardization of the EEBUS protocol suite is driven by the members of the EEBus Initiative e.V. The collaboration is organized in working groups. The current set of working groups is HVAC, inverters, white goods, grid interaction, and e-mobility. New working groups can be initiated by EEBUS members at will.
Energy management in the context of electric vehicles has been harmonized with ISO 15118.
The Ontology of EEBUS has been standardized in the ETSI SAREF standard.
Adoption
Membership
The number of members varies from year to year and depending on sources, starting from "more than 50" (in 2019), "about 60" (in 2016), or even 70 members (in 2019).
The EEBus initiative's website lists 61 members as of 2020.
Commercial/industry application
The EEBUS standard has been adopted by manufacturers of electric cars, Home Energy Management Systems, HVAC manufacturers, and others. The most prominent example showing the maturity of the EEBUS standard is a fully functional ecosystem involving photovoltaic panels for local electricity generation, an energy manager, charging equipment, and an Audi e-tron. Other examples that build on the same logic include the non-domestic application for cooling supermarkets.
Microsoft has decided to implement EEBUS on their embedded platform Azure Sphere.
Research/academia
The standard is also utilized in pan-European research and commercial projects that deal with the integration of different electric appliances at the grid connection point of a dwelling.
For instance, an implementation in 240 residential Dutch homes has been successfully tested within the REnovates project.
The Interconnect project has been launched in October 2019 to further specify, implement and test smart grid applications based on EEBUS and KNX to ensure interoperability among different vendors and distribution system operators.
Partnerships
Open Charge Alliance
Energy Home
Open Connectivity Foundation (OCF)
Thread Group
ESMIG
Reception/criticism
Entry barrier
The participation in working groups and the availability of draft and release candidate versions of the specifications is bound to an EEBUS membership. (10.000 EUR per year; 5.000 EUR if the company's turnover is below 5 Million EUR and the company has less than 50 employees.)
No royalty-free reference implementation
Former EEBUS member grandcentrix expressed concerns about the lack of a royalty-free reference implementation, saying this was the core reason the standard does not see broader adoption.
References
Smart grid
Home automation | EEBUS | [
"Technology"
] | 913 | [
"Home automation"
] |
63,004,431 | https://en.wikipedia.org/wiki/Dichapetalins | Dichapetalins are a small class of triterpenoid compounds found primarily in the Dichapetalaceae family but also reportedly in Phyllanthus (Euphorbiaceae). They are structural derivatives of dammarene characterized by a C6C2 unit connected to a dammarene or a 13,30-cyclodammarane skeleton with variable C-17 side chains containing actone, spirolactone, lactol, acetal, or furan moieties. They have been found to display cytotoxicity against several cancer cell lines.
References
Triterpenes | Dichapetalins | [
"Chemistry"
] | 130 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
63,005,409 | https://en.wikipedia.org/wiki/Paul%20Braterman | Paul Sydney Braterman (born August 1938) is Emeritus Professor of chemistry at the University of North Texas and honorary senior Research Fellow in Chemistry at the University of Glasgow. Braterman is also a science writer and education campaigner. The author of From Stars to Stalagmites, and over 120 technical publications, Braterman is a board member of the British Centre for Science Education, and the Scottish Secular Society. Braterman has campaigned successfully against creationism in the classroom in both England and Scotland.
Education and career
The grandson of Eastern European Jewish immigrants, Braterman was born and raised in London. He received his Master of Arts and DPhil degrees from Balliol College, Oxford. In 1985 he received a DSc degree.
After postdoctoral research at University College London (adviser Robert Williams), and University of California at Los Angeles (advisers Herbert D. Kaesz and Mostafa El-Sayed), he worked in the chemistry departments of the University of Glasgow, where he rose to the rank of reader, and the University of North Texas as professor and chair, and later as Regents Professor, with several periods as visiting investigator at Scripps Institution of Oceanography at the University of California San Diego, and Sandia National Laboratories.
Braterman's work has been supported by the Robert A. Welch Foundation, the National Science Foundation, and NASA’s exobiology and astrobiology programs, for which he also served as an adviser.
In 2007, he returned to Glasgow where he is now an Honorary Senior Research Fellow.
Research
Braterman is the author of over 120 technical publications and two academic books. He worked as a physical inorganic chemist, but with interests crossing traditional subject boundaries.
An interest in metal carbonyl spectroscopy led on to work on bonding and reactivity in organometallic chemistry. A long-standing interest in charge transfer phenomena, and their possible relevance to photochemical water splitting, led to studies of combined spectroscopy and electrochemistry in Bipyridine derivatives and their transition metal complexes.
Under the influence of Graham Cairns-Smith, he became interested in photochemical and other possible reactions on the early Earth, in connection with the origins of life, and later in isotopic fractionation https://en.wikipedia.org/wiki/Isotope_geochemistry as evidence of reactions taking place there. In view of the possible importance of minerals in the origins of life, he investigated as model systems, the formation and stability of layered double hydroxides, their interaction with chemically bound organic molecules, and effects on particle morphology.
Activism and writing
Since returning to Glasgow in 2007, Paul Braterman has concentrated on educational activities, writing for a broad audience, and campaigning in defence of science education. He is on the board of the British Centre for Science Education, and scientific adviser to the Scottish Secular Society His work with these organisations led to the blocking of teaching of creationism as science in both English and Scottish schools.
His first popular science book, From Stars to Stalagmites, was a Scientific American book club choice.
He has been a regular contributor to 3 Quarks Daily, and his writing has appeared in The Conversation, Scientific American, Newsweek, International Business Times, and Massimo Pigliucci’s Scientia Salon.
Braterman has also contributed to The Panda's Thumb (blog) in an article entitled Creationism and climate - Birth of a new Pseudoscience.
References
1938 births
Inorganic chemists
Alumni of Balliol College, Oxford
Living people
Scientists from London
20th-century Scottish chemists
21st-century Scottish chemists
University of North Texas faculty | Paul Braterman | [
"Chemistry"
] | 728 | [
"British inorganic chemists",
"Inorganic chemists"
] |
63,005,595 | https://en.wikipedia.org/wiki/Human%20Compatible | Human Compatible: Artificial Intelligence and the Problem of Control is a 2019 non-fiction book by computer scientist Stuart J. Russell. It asserts that the risk to humanity from advanced artificial intelligence (AI) is a serious concern despite the uncertainty surrounding future progress in AI. It also proposes an approach to the AI control problem.
Summary
Russell begins by asserting that the standard model of AI research, in which the primary definition of success is getting better and better at achieving rigid human-specified goals, is dangerously misguided. Such goals may not reflect what human designers intend, such as by failing to take into account any human values not included in the goals. If an AI developed according to the standard model were to become superintelligent, it would likely not fully reflect human values and could be catastrophic to humanity. Russell asserts that precisely because the timeline for developing human-level or superintelligent AI is highly uncertain, safety research should be begun as soon as possible, as it is also highly uncertain how long it would take to complete such research.
Russell argues that continuing progress in AI capability is inevitable because of economic pressures. Such pressures can already be seen in the development of existing AI technologies such as self-driving cars and personal assistant software. Moreover, human-level AI could be worth many trillions of dollars. Russell then examines the current debate surrounding AI risk. He offers refutations to a number of common arguments dismissing AI risk and attributes much of their persistence to tribalism—AI researchers may see AI risk concerns as an "attack" on their field. Russell reiterates that there are legitimate reasons to take AI risk concerns seriously and that economic pressures make continued innovation in AI inevitable.
Russell then proposes an approach to developing provably beneficial machines that focus on deference to humans. Unlike in the standard model of AI, where the objective is rigid and certain, this approach would have the AI's true objective remain uncertain, with the AI only approaching certainty about it as it gains more information about humans and the world. This uncertainty would, ideally, prevent catastrophic misunderstandings of human preferences and encourage cooperation and communication with humans. Russell concludes by calling for tighter governance of AI research and development as well as cultural introspection about the appropriate amount of autonomy to retain in an AI-dominated world.
Russell's three principles
Russell lists three principles to guide the development of beneficial machines. He emphasizes that these principles are not meant to be explicitly coded into the machines; rather, they are intended for human developers. The principles are as follows:
The "preferences" Russell refers to "are all-encompassing; they cover everything you might care about, arbitrarily far into the future." Similarly, "behavior" includes any choice between options, and the uncertainty is such that some probability, which may be quite small, must be assigned to every logically possible human preference.
Russell explores inverse reinforcement learning, in which a machine infers a reward function from observed behavior, as a possible basis for a mechanism for learning human preferences.
Reception
Several reviewers agreed with the book's arguments. Ian Sample in The Guardian called it "convincing" and "the most important book on AI this year". Richard Waters of the Financial Times praised the book's "bracing intellectual rigour". Kirkus Reviews endorsed it as "a strong case for planning for the day when machines can outsmart us".
The same reviewers characterized the book as "wry and witty", or "accessible" due to its "laconic style and dry humour". Matthew Hutson of the Wall Street Journal said "Mr. Russell's exciting book goes deep while sparkling with dry witticisms". A Library Journal reviewer called it "The right guide at the right time".
James McConnachie of The Times wrote "This is not quite the popular book that AI urgently needs. Its technical parts are too difficult, and its philosophical ones too easy. But it is fascinating and significant."
By contrast, Human Compatible was criticized in its Nature review by David Leslie, an Ethics Fellow at the Alan Turing Institute; and similarly in a New York Times opinion essay by Melanie Mitchell. One point of contention was whether superintelligence is possible. Leslie states Russell "fails to convince that we will ever see the arrival of a 'second intelligent species, and Mitchell doubts a machine could ever "surpass the generality and flexibility of human intelligence" without losing "the speed, precision, and programmability of a computer". A second disagreement was whether intelligent machines would naturally tend to adopt so-called "common sense" moral values. In Russell's thought experiment about a geoengineering robot that "asphyxiates humanity to deacidify the oceans", Leslie "struggles to identify any intelligence". Similarly, Mitchell believes an intelligent robot would naturally tend to be "tempered by the common sense, values and social judgment without which general intelligence cannot exist".
The book was longlisted for the 2019 Financial Times/McKinsey Award.
See also
Artificial Intelligence: A Modern Approach
Center for Human-Compatible Artificial Intelligence
The Precipice: Existential Risk and the Future of Humanity
Slaughterbots
Superintelligence: Paths, Dangers, Strategies
References
External links
Interview with Stuart J. Russell
American non-fiction books
2019 non-fiction books
English-language non-fiction books
Existential risk from artificial general intelligence
Futurology books
Technology books
Viking Press books
Non-fiction books about Artificial intelligence | Human Compatible | [
"Technology"
] | 1,108 | [
"Existential risk from artificial general intelligence"
] |
63,006,182 | https://en.wikipedia.org/wiki/Diphenic%20acid | Diphenic acid, also known as Dibenzoic acid, is an organic compound with the formula (C6H4CO2H)2. It is the most studied of several isomeric dicarboxylic acids of biphenyl. It is a white solid that can be prepared in the laboratory from anthranilic acid via the diazonium salt. It is the product of the microbial action on phenanthrene.
The compound forms a variety of coordination polymers. It also exhibits atropisomerism. It can form an internal anhydride featuring a seven-membered ring fused to the two benzene rings.
Preparation
Diphenic acid is prepared from anthranilic acid by diazotization, followed by reduction with copper(I).
It can also be synthesized from the oxidation of phenanthrene by peracetic acid, which is first prepared from acetic acid and 90% hydrogen peroxide:
CH3COOH + H2O2 ⇌ CH3COOOH + H2O
4 CH3COOOH + C14H10 → 4 CH3COOH + C14H10O4
Phenanthrene can also be treated with other oxidizing agents (such as hydrogen peroxide, chromium trioxide, potassium dichromate, or potassium permanganate), which first yields phenanthrenequinone and gives diphenic acid on further oxidation. Similarly, phenanthrenequinone can be boiled in alcoholic potash (potassium hydroxide in alcohol) to give the potassium salt of diphenic acid, and can alternatively be photo-oxidized to diphenic acid.
References
Biphenyls
Benzoic acids
Carboxylic acids | Diphenic acid | [
"Chemistry"
] | 368 | [
"Carboxylic acids",
"Functional groups"
] |
63,006,719 | https://en.wikipedia.org/wiki/Leonard%20G.%20Montefiore | Leonard Nathaniel Goldsmid-Montefiore (2 June 1889 – 23 December 1961) was a wealthy member of the Montefiore family, the only son of Claude Montefiore, and he succeeded his father as a leader of Jewish philanthropic organisations in the UK including the Anglo-Jewish Association, the Central British Fund for German Jewry, and the Jewish Board of Guardians. He was a founder and president of the Wiener Library for the Study of the Holocaust and Genocide.
Early life
He was the only son of Claude Montefiore—a prominent Jewish scholar and philanthropist—and was named after his uncle Leonard A. Montefiore. He was born at the family home of number 12, Portman Square on 2 June 1889. His mother, Therese Alice, died on the following day, and so he was brought up by his grandmother, Emma Montefiore, who was from the wealthy Goldsmid family.
He was educated at Clifton College and Balliol College, Oxford, where he read history. While a student, he spent time in Berlin and Hanover, where he became fluent in German. After graduation, he worked and lived at Toynbee Hall—a settlement house in which rich people lived alongside the poor to do social work and alleviate poverty.
In 1914, at the start of the First World War, he joined a cycling battalion of the Royal Hampshire Regiment. He served in India and Siberia, rising to the rank of captain. In 1918, he was admitted to the Order of the British Empire, and in 1921 he joined the Athenaeum Club, being introduced by Viscount Milner.
In 1924, he married the sister of a close friend from college, Muriel Jeanetta Tuck (1892–1988), the youngest daughter of Adolph Tuck (whose wealthy family ran Raphael Tuck & Sons). They had two sons, David and Alan, who became a physician and Oxford don respectively. In 1924, he also campaigned in Soho for the election of Winston Churchill as an Independent, in the Westminster Abbey by-election.
Charitable service
Leonard Montefiore was active in numerous charitable, cultural, and philanthropic organisations. Chaim Bermant wrote, "He attended them all, gave money to them all, offered guidance to them all".
These organisation included:
Anglo-Jewish Association – president, vice-president, chairman of the industrial committee
Bernhard Baron Settlement
Central British Fund for German Jewry
Clifton College – governor
Froebel Educational Institute – chairman 1939–1961
Jewish Association for the Protection of Girls and Women
Jewish Board of Guardians – chairman of the industrial committee
Jewish Colonization Association
Jewish Refugees Committee – chairman
Jews’ Free School
Jews’ Temporary Shelter
League of British Jews
Leo Baeck College – chairman
Reform Synagogues Association – president
West London Synagogue – reader, senior treasurer, vice-president and warden
Wiener Library – founder and president
Germany and the Second World War
When Adolf Hitler became Chancellor of Germany in 1933 and his National Socialist party seized power, it threatened the Jewish community in Germany. Montefiore was at that time co-chairman of the Joint Foreign Committee of the Anglo-Jewish Association and the Board of Deputies of British Jews; the other co-chairman was Neville Laski. This committee had a tradition of protecting and supporting overseas Jews and it then established the Central British Fund for German Jewry. Another founder member was Otto Schiff, who organised the Jewish Refugees Committee, which Montefiore chaired. The wealth supporting this fund enabled a promise to be made to the British government that Jewish refugees from Germany would not be a burden on public finances. They also lobbied British society to protest against German discrimination against Jews but were not successful initially. Others wanted to organise a boycott of German goods but the Board of Deputies saw this as too extreme. There was also concern about Zionist influence, which the Board opposed as subverting their status as British. Montefiore was himself opposed to Zionism until he visited Israel in 1955.
Montefiore's fluency in the German language enabled him to study the details of the oppression of the Jews in Germany. He publicised these, writing articles, letters and pamphlets including The Jews in Germany: Facts and Figures (1934) and Exiles from Germany (1937).
In 1944, he toured the Mediterranean theatre to meet Jewish servicemen for the Welfare Branch of the War Office.
The Windermere children
Montefiore organised aid for hundreds of Jewish orphans after the Second World War, acting as their guardian and arranging for them to be flown to England in heavy bombers by the RAF. They had been liberated from Nazi concentration camps and so required care and rehabilitation for which he arranged a special camp at Windermere. Montefiore made regular visits and took a personal interest in their development. Nurse Eva Kahn-Minden recalled his manner,
This refugee rescue was dramatised as The Windermere Children and broadcast by the BBC in 2020 for the 75th anniversary of the liberation of Auschwitz. In this production, the part of Leonard Montefiore was played by Tim McInnerny.
References
1889 births
1961 deaths
Alumni of Balliol College, Oxford
British Reform Jews
Jewish British philanthropists
Members of the Order of the British Empire
Rescue of Jews during the Holocaust
Royal Hampshire Regiment officers
Wiener Library | Leonard G. Montefiore | [
"Biology"
] | 1,045 | [
"Rescue of Jews during the Holocaust",
"Behavior",
"Altruism"
] |
63,006,760 | https://en.wikipedia.org/wiki/Reindeer%20distribution | The reindeer (caribou in North America) is a widespread and numerous species in the northern Holarctic, being present in both tundra and taiga (boreal forest). Originally, the reindeer was found in Scandinavia, eastern Europe, Russia, Mongolia, and northern China north of the 50th latitude. In North America, it was found in Canada, Alaska (United States), and the northern contiguous USA from Washington to Maine. In the 19th century, it was apparently still present in southern Idaho. It also occurred naturally on Sakhalin, Greenland, and probably even in historical times in Ireland.
During the late Pleistocene era, reindeer were found further south, such as at Nevada, Tennessee, and Alabama in North America and Spain in Europe. Today, wild reindeer have disappeared from many areas within this large historical range, especially from the southern parts, where it vanished almost everywhere. Populations of wild reindeer are still found in Norway, Finland, Siberia, Greenland, Alaska, and Canada.
The George River reindeer herd in the tundra of Quebec and Labrador in eastern Canada, once numbered world's largest 8–900,000 animals, stands December 2011 at 74,000 – a drop of up to 92% because of Iron-ore mining, flooding for hydropower and road building.
Domesticated reindeer are mostly found in northern Fennoscandia and Russia, with a herd of approximately 150–170 semi-domesticated reindeer living around the Cairngorms region in Scotland. Although formerly more widespread in Scandinavia, the last remaining wild mountain reindeer in Europe are found in portions of southern Norway. Siberian tundra reindeer are widespread in Russia.
A few reindeer from Norway were introduced to the South Atlantic island of South Georgia in the beginning of the 20th century. The South Georgian reindeer totaled some estimated 2600 animals in two distinct herds separated by glaciers. Although the flag and the coat of arms of the territory contain an image of a reindeer, they were eradicated from 2013 to 2017 because of the environmental damage they caused. Around 4000 reindeer have been introduced into the French sub-Antarctic archipelago of Kerguelen Islands. East Iceland has a small herd of about 2500–3000 animals.
Caribou and reindeer numbers have fluctuated historically, but many herds are in decline across their range. This global decline is linked to climate change for northern, migratory caribou and reindeer herds and industrial disturbance of caribou habitat for sedentary, non-migratory herds.
Russia
In 2013, the Taimyr herd in Russia was the largest herd in the world. In 2000, the herd increased to 1,000,000 but by 2009, there were 700,000 animals. In the 1950s, there were 110,000.
There are three large herds of migratory tundra wild reindeer in central Siberia's Yakutia region: the Lena-Olenek, Yana-Indigirka and Sundrun herds. While the population of the Lena-Olenek herd is stable, the others are declining.
Further east again, the Chukotka herd is also in decline. In 1971, there were 587,000 animals. They recovered after a severe decline in 1986, to only 32,200 individuals, but their numbers fell again. According to Kolpashikov, by 2009 there were less than 70,000.
North America
Until a recent revision, there were six living subspecies of the reindeer (Rangifer tarandus), known in North America as the caribou: woodland (boreal), R. t. caribou; Labrador or Ungava caribou, R. t. caboti; Newfoundland caribou, R. t. terranovae; barren-ground caribou, R. t. groenlandicus (including the Porcupine, Dolphin-Union and other Alaskan and Canadian herds of barren-ground caribou); Osborn's caribou, R. t. oborni; and Peary caribou, R. t. pearyi.
In Canada, the Committee on Status of Endangered Wildlife in Canada (COSEWIC) defined 12 "designatable units", DU, which included the above named subspecies and several ecotypes: Peary caribou DU1, the Dolphin-Union herd of barren-ground caribou DU2, mainland barren-ground (including Alaskan) caribou DU3, Labrador caribou ("eastern migratory") caribou DU4, Newfoundland caribou DU5, boreal woodland caribou DU6, Osborn's caribou ("northern mountain") DU7, Rocky Mountain caribou ("central mountain") DU8, Selkirk Mountain caribou DU9 ("southern mountain"), Torngat Mountain DU10 (an ecotype of Labrador caribu), Atlantic-Gaspésie DU11 (a montane ecotype of woodland caribou) and the extinct Dawson's caribou DU2. Genetic research has shown that Osborn's caribou and the other two western montane ecotypes are of Beringian-Eurasian ancestry (but distantly, having diverged > 60,000 years ago) and therefore not closely relate to woodland caribou (see Reindeer: Evolution and Reindeer: Taxonomy). While useful for conservation and research, Designatable units, an adaptation of "evolutionary significant units", are not phylogenetically based and cannot substitute for taxonomy.
In North America, because of its vast range in a wide diversity of ecosystems, the woodland caribou is further distinguished by a number of ecotypes. In the Ungava region of Quebec, several herds of Labrador caribou in the north, such as the large George River caribou herd, overlap in range with the boreal woodland caribou to the south.
A recent revision returned Woodland caribou to species status, R. caribou, with subspecies Labrador or Ungava caribou, R. c. caboti, the migratory form; Newfoundland caribou, R. c. terranovae; and Boreal woodland caribou, R. c. caribou. The revision returned the name of Arctic caribou to its original R. arcticus, with the nominate subspecies being barren-ground caribou, R. a. arcticus, and returned four western montane ecotypes to subspecies of Arctic caribou: Selkirk Mountain caribou, R. a. montanus, Rocky Mountain caribou, R. a. fortidens, Osborn's caribou, R. a. osborni, and Stone's caribou, R. a. stonei, in accordance with molecular data that showed these to be of Beringian-Eurasian ancestry (see Reindeer: Evolution and Taxonomy).
Some caribou populations are "endangered in Canada in regions such as southeastern British Columbia at the Canadian-USA border, along the Columbia, Kootenay and Kootenai rivers and around Kootenay Lake. Selkirk Mountain caribou (formerly thought to be an ecotype of woodland caribou, Rangifer tarandus caribou) was considered endangered in the United States in Idaho and Washington. R. t. pearyi is on the IUCN endangered list. The woodland caribou is highly endangered throughout its distribution.
United States
All U.S. caribou populations are in Alaska. There was also a remnant population of about a dozen caribou in the Selkirk Mountains of Idaho, which were the only remaining wild caribou in the contiguous United States. In 2018 there were three left; the last member, a female, was transported to a wildlife rehab center in Canada, thus marking the extirpation of the caribou from the Lower 48.
Alaska
There are four migratory herds of barren-ground caribou, R. tarandus groenlandicus, in Alaska: the Western Arctic herd, the Teshekpuk Lake herd, the Central Arctic herd and the Porcupine caribou herd (named for a river that flows from Yukon into Alaska), the last of which is transnational as its migratory range extends far into Canada's north. The largest is the Western Arctic caribou herd, but the smaller Porcupine herd has the longest migration of any terrestrial mammal on Earth with a vast historical range. There are also about 20 montane herds in the south and east, recently returned to their former name, R. a. stonei, that move seasonally within their small ranges, but to not migrate per se; and one nearly insular herd on the western end of the Alaska Peninsula and nearby islands, originally described as R. granti. Phylogenetic analysis shows that Grant's caribou clusters separately from all other Alaskan caribou and does not interbreed with nearby caribou ecotypes.
Porcupine caribou herd
The Porcupine caribou herd is transnational and migratory. The herd is named after their birthing grounds, for example, the Porcupine River, which runs through a large part of the range of the Porcupine herd. Individual herds of migratory caribou once had over a million animals per herd and could take over ten days to cross the Yukon River, but these numbers dramatically declined with habitat disturbance and degradation. Though numbers fluctuate, the herd comprises approximately 169,000 animals (based on a July 2010 photocensus). The Porcupine herd's annual migrations of are among the longest of any terrestrial mammal. Its range spans approximately , from Aklavik, Northwest Territories to Dawson City, Yukon to Kaktovik, Alaska on the Beaufort Sea. The Porcupine caribou (R. tarandus groenlandicus (originally named Tarandus rangifer ogilviensis Millais 1915 after the Ogilvie Mountains, their Yukon winter range; see Reindeer: Taxonomy) has a vast range that includes northeastern Alaska and the Yukon and is therefore cooperatively managed by government agencies and aboriginal peoples from both countries. The Gwich'in people followed the Porcupine herd—their primary source of food, tools, and clothing—for thousands of years—according to oral tradition, for as long as 20,000 years. They continued their nomadic lifestyle until the 1870s. This herd is also traditional food for the Inupiat, the Inuvialuit, the Hän, and the Northern Tutchone. There is currently controversy over whether possible future oil drilling on the coastal plains of the Arctic National Wildlife Refuge, encompassing much of the Porcupine caribou calving grounds, will have a severe negative impact on the caribou population or whether the caribou population will grow.
Unlike many other barren-ground caribou, the Porcupine caribou is stable at relatively high numbers, but the 2013 photo census was not counted by January 2014. The peak population in 1989 of 178,000 animals was followed by a decline by 2001 to 123,000. By 2010, it recovered to 169,000.
Many Gwich'in people, who depend on the Porcupine herd, still follow traditional caribou management practices that include a 1981 prohibition against selling caribou meat and limits on the number of caribou to be taken per hunting trip.
Western Arctic caribou herd (WACH)
The Western Arctic caribou herd is the largest of the three Alaskan barren-ground caribou herds. The Western Arctic herd reached a low of 75,000 in the mid-1970s. In 1997 the 90,000 WACH changed their migration and wintered on Seward Peninsula. Alaska's reindeer herding industry has been concentrated on Seward Peninsula ever since the first shipment of reindeer was imported from eastern Siberia in 1892 as part of the Reindeer Project, an initiative to replace whale meat in the diet of the indigenous people of the region. For many years it was believed that the geography of the peninsula would prevent migrating caribou from mingling with domesticated reindeer who might otherwise join caribou herds when they left an area. In 1997, the domesticated reindeer joined the Western Arctic caribou herd on their summer migration and disappeared. The WACH reached a peak of 490,000 in 2003 and then declined to 325,000 in 2011.
Teshekpuk Lake and Central Arctic caribou herds
In 2008, the Teshekpuk Lake caribou herd had 64,107 animals and the Central Arctic caribou herd had 67,000.
By 2017, the Teshekpuk herd's numbers, whose calving grounds are in the region of the shallow Teshekpuk Lake, had declined to 41,000 animals. Teshekpuk Lake in the North Slope is in the traditional lands of the Iñupiat, who depended on the Teshekpuk herd for millennia. Teshekpuk Lake is also in the National Petroleum Reserve-Alaska, where the U.S. Department of the Interior (DOI) had approved oil and gas drilling on 11 January 2006. The NPR-A is the "single largest parcel of public land in the United States" covering about 23 million acres". The reserve's eastern border sits about 100 miles to the west of the more famous Arctic National Wildlife Refuge. The leasing of Teshekpuk Lake land to industry was protested by the Iñupiat and others who sent 300,000 letters to the US Secretary of the Interior and the ConocoPhillips CEO over the summer of 2006. On 25 September 2006, the U.S. District Court for the District of Alaska protected the wildlife habitat around the lake from an oil and gas lease sale.
In October 2017, U. S. Secretary of the Interior, Ryan Zinke, announced that as of 6 December 2017, lands under the administration of the U.S. Bureau of Land Management will be up for bid on the "largest offering of public lands for lease in the history of the [BLM] — 10.3 million acres". The Prudhoe Bay Oil Field, near Prudhoe Bay, Alaska, is situated between the Arctic National Wildlife Refuge to the east. Industry will be allowed to run "roads, pipelines and drill rigs" in the very sensitive habitat areas, including the Teshekpuk caribou herd calving grounds. The Teshekpuk herd remains at the calving grounds for several weeks in spring before moving from Teshekpuk Lake for relief from mosquitoes and botflies before their annual migration.
Reindeer imported to Alaska
Reindeer were imported from Siberia in the late 19th century and from Norway in the early 1900s as semi-domesticated livestock in Alaska. Reindeer can interbreed with the native caribou subspecies, but they rarely do, and even then their offspring do not survive well in the wild.
Canada
Nunavut
The barren-ground caribou (R. t. groenlandicus), a long-distance migrant, includes large herds in the Northwest Territories and in Nunavut, for example, the Beverly, the Ahiak and Qamanirjuaq herds. In 1996, the population of the Ahiak herd was approximately 250,000 animals.
Ahiak, Beverly and Qamanirjuaq caribou herds
The Ahiak, Beverly and Qamanirjuaq caribou herds are all barren-ground caribou.
"The Beverly herd’s crossing of the Thelon River to its traditional calving grounds near Beverly Lake was part of the lives of the Dene aboriginal people for 8,000 years, as revealed by an unbroken archaeological record of deep layers of caribou bones and stone tools in the banks of the Thelon River (Gordon 2005)." The Beverly herd (located primarily in Saskatchewan, Northwest Territories; with portions in Nunavut, Manitoba and Alberta) and the Qamanirjuaq Herd (located primarily in Manitoba, Nunavut; with portions in the southeastern NWT and northeastern Saskatchewan) fall under the auspices of the Beverly and Qamanirjuaq Caribou Management Board. The Beverly herd, whose range spans the tundra from northern Manitoba and Saskatchewan and well into the Northwest Territories and Nunavut, had a peak population in 1994 of 276,000 or 294,000, but by 2011 there were approximately 124,000 caribou in the Beverly herd and 83,300 in the Ahiak herd. The calving grounds of the Beverly herd are located around Queen Maud Gulf, but the herd shifted its traditional birthing area. Caribou management agencies are concerned that deterioration and disturbance of habitat along with "parasites, predation and poor weather" are contributing to a cycling down of most caribou populations. It was suggested the Ahiak and Beverly herds switched calving grounds and the Beverly may have moved "near the western Queen Maud Gulf coast to the north of the herd’s "traditional" calving ground in the Gary Lakes area north of Baker Lake." The "Beverly herd may have declined (similar to other Northwest Territories herds), and cows switched to the neighbouring Ahiak herd to maintain the advantages of gregarious calving." By 2011 there were approximately 124,000 caribou in the combined Beverly/Ahiak herd which represents a "50% or a 75% decline from the 1994 population estimate for the Beverly Herd."
The barren-ground caribou population on Southampton Island, Nunavut declined by almost 75%, from about 30,000 caribou in 1997 to 7,800 caribou in 2011.
Peary caribou
The Peary caribou (R. t. pearyi), the smallest subspecies in North America, known as tuktu in Inuktitut, are found in the northern islands of Nunavut (except Baffin Island) and the Northwest Territories. They remain at low numbers after severe declines.
A population of barren-ground caribou (R. t. groenlandicus) summers on Victoria Island and crosses the ice of Dolphin and Union Strait to the lands around Coronation Gulf for winter. Once thought to be hybrids or intergrades with Peary caribou, they are now known to be a barren-ground caribou named after the strait that they migrate across: Dolphin-Union caribou. Further research showed that some R. t. pearyi x groenlandicus hybrids occur on Banks Island and the northwest corner of Victoria Island.
Baffin Island caribou
On Baffin Island, the largest Arctic island, the population of barren-ground caribou (R. t. groenlandicus) peaked in the early 1990s to approximately 60,000 to 180,000. By 2012, in northern Baffin Island caribou numbers were considered to be at a "low in the cycle after a high in the 1990s" and in southern Baffin Island, the population was estimated as between 1,065 and 2,067. Baffin Island caribou are highly divergent from other barren-ground caribou, have a different mating system, lack migratory and aggregation behaviors, and have morphological differences.
The Northwest Territories
There are four barren-ground caribou herds in the Northwest Territories—the Cape Bathurst, Bluenose West, Bluenose East and Bathurst herds. The Bluenose East caribou herd began a recovery with a population of approximately 122,000 in 2010, which is being credited to the establishment of Tuktut Nogait National Park. According to T. Davison 2010, CARMA 2011, the three other herds "declined 84–93% from peak sizes in the mid-1980s and 1990s.
R. t. caribou
The Committee on Status of Endangered Wildlife in Canada (COSEWIC) divided woodland caribou (R. tarandus caribou) ecotypes into five "Designatable Units" (DU) as noted above. Caribou are classified by ecotype depending on several behavioral factors – predominant habitat use (northern, tundra, mountain, forest, boreal forest, forest-dwelling), spacing (dispersed or aggregated) and migration patterns (sedentary or migratory).
In Canada, the national meta-population of the sedentary boreal woodland ecotype spans the boreal forest from the Northwest Territories to Labrador. They prefer lichen-rich mature forests and mainly live in marshes, bogs, lakes and river regions. The historic range of the boreal woodland caribou covered over half of present-day Canada, stretching from Alaska to Newfoundland and Labrador and as far south as New England, Idaho and Washington. Woodland caribou have disappeared from most of their original southern range and only about 34,000 remain. The boreal woodland caribou was designated as threatened in 2002.
George River caribou herd (GRCH)
The migratory George River caribou herd (GRCH), in the Ungava region of Quebec and Labrador in eastern Canada was once the world's largest caribou herd with 800,000–900,000 animals. It is a herd of Labrador caribou, Rangifer tarandus caboti. The GRCH is the migratory woodland caribou and, like the barren-ground caribou, its ecotype may be tundra caribou, Arctic, northern or migratory, not forest-dwelling and sedentary like most woodland caribou ecotypes. It is unlike most woodland caribou in that it is not sedentary. Since the mid-1990s, the herd declined sharply and by 2010, it was reduced to 74,131—a drop of up to 92%. A 2011 survey confirms a continuing decline of the George River caribou herd population. By 2018 it was estimated to be fewer than 9,000 animals as reported by the Canadian Broadcasting Corporation, down from 385,000 in 2001 and 74,131 in 2010.
Leaf River caribou herd (LRCH)
The Leaf River caribou herd (LRCH), another migratory herd of Labrador caribou, near the coast of Hudson Bay, increased from 270 000 individuals in 1991 to 628 000 in 2001. By 2011 the herd had decreased to 430 000. According to an international study on caribou populations, the George River and Leaf River herds and other herds that migrate from Nunavik, Quebec and insular Newfoundland, could be threatened with extinction by 2080.
Queen Charlotte Islands caribou
The Queen Charlotte Islands caribou (formerly R. t. dawsoni) from Graham Island, the largest of the Queen Charlotte Islands, is a distinct subspecies. It became extinct at the beginning of the 20th century. Recent DNA analysis from mitochondrial DNA taken from the remains of these caribou suggest that the animals from the Queen Charlotte Islands were genetically close to from the adjacent mainland caribou subspecies, Osborn's caribou, now recognized as of Beringian-Eurasian lineage.
Greenland
Four main populations of Greenland reindeer and caribou (Originally Cervus [Rangifer] grönlandicus Borowski, 1780) occupied western Greenland in 2013. The Kangerlussuaq-Sisimiut caribou herd, the largest, had a population of around 98,000 animals in 2007. The second largest, the Akia-Maniitsoq caribou herd, decreased from an estimated 46,000 in 2001 to about 17,400 in 2010. According to Cuyler, "one possible cause might be the topography, which prevents hunter access in the former while permitting access in the latter."
Greenland reindeer, formerly recognized as a full species, are the most genetically divergent of all caribou and reindeer, with an average genetic distance (FST) of 44%. Unlike barren-ground caribou, they have a harem-defense mating system, migrate only short (< 60 km) distances if at all, and lack the rutting and post-calving aggregation behavior of barren-ground caribou. Genetic, behavioral and morphological differences from other caribou and reindeer are so great that a recent revision returned them to full species status.
Norway
The last remaining wild tundra reindeer in Europe are found in portions of southern Norway. In southern Norway in the mountain ranges, there are about 30,000–35,000 reindeer with 23 different populations. The largest herd, with about 10,000 individuals, is at Hardangervidda. By 2013 the greatest challenges to management were "loss of habitat and migration corridors to piecemeal infrastructure development and abandonment of reindeer habitat as a result of human activities and disturbance."
Norway is now preparing to apply for nomination as a World Heritage Site for areas with traces and traditions of reindeer hunting in Dovrefjell-Sunndalsfjella National Park, Reinheimen National Park and Rondane National Park in Central Sør-Norge (Southern Norway). There is in these parts of Norway an unbroken tradition of reindeer hunting from the post-glacial Stone Age until today.
On 29 August 2016, the Norwegian Environment Agency announced the death of 323 reindeer by the effects of a lightning strike in Hardangervidda.
On 3 December 2018 a hiker in Northern Norway reported a sighting, and posted photos, of a rare white reindeer calf.
Svalbard reindeer
The Svalbard reindeer (R. tarandus platyrhynchus) from Svalbard Island is very small compared to other subspecies (a phenomenon known as insular dwarfism) and is the smallest of all the subspecies, with females having a length of approximately , and a weight around in the spring and in the autumn. Males are approximately long, and weigh around in the spring and in the autumn. The reindeer from Svalbard are also relatively short-legged and may have a shoulder height of as little as , thereby following Allen's rule.
The Svalbard reindeer seems to have evolved from large European reindeer, and is special in several ways: it has peculiarities in its metabolism, and its skeleton shows a remarkable relative shortening of the legs, thus parallelling many extinct insular deer species.
Sweden
Reindeer inhabit mostly northern parts of Sweden and the central Swedish province of Dalarna. In northern Sweden and parts of Dalarna, reindeer herding activity is generally part of the lifestyle of the indigenous Sámi people.
Finland
The Finnish forest reindeer (R. t. fennicus), is found in the wild in only two areas of the Fennoscandia peninsula of Northern Europe, in Finnish/Russian Karelia and a small population in central south Finland. The Karelia population reaches far into Russia, and genetic research shows that the Altai-Sayan forest reindeer, R. t. valentinae, clusters together with Finnish forest reindeer and apart from tundra reindeer, R. t. sibiricus. By 2007 reindeer experts were concerned about the collapse of the wild Finnish forest reindeer in the eastern province of Kainuu. During the peak year of 2001, the Finnish forest reindeer population in Kainuu was established at 1,700. In a March 2007 helicopter count, only 960 individuals were detected.
Iceland
East Iceland has a small herd of about 2,500–3,000 animals. Reindeer were introduced to Iceland in the late 1700s. The Icelandic reindeer population in July 2013 was estimated at approximately 6,000. With a hunting quota of 1,229 animals, the winter 2013–2014 population is expected to be around 4,800 reindeer.
United Kingdom
Semi-domesticated reindeer of domestic stock were brought to Scotland in 1952. In 2017, there were about 150 left to graze across 10,000 acres of land in the Cairngorms National Park, where the climate is classed as tundra.
A few reindeer from Norway were introduced to the South Atlantic island of South Georgia in the beginning of the 20th century. The South Georgian reindeer totaled some estimated 2,600 animals in two distinct herds separated by glaciers. Although both the flag and the coat of arms of the territory contain an image of a reindeer, a decision was taken in 2011 to completely eradicate the animals from the island because of the environmental damage they cause, which was done so with a team of Norwegian Sami hunters from 2013 to 2017, which revealed the true count to be around 6,750.
French overseas territory experiment
Around 4,000 reindeer are descendants to those who have been introduced into the French sub-Antarctic archipelago of the Kerguelen Islands.
References
External links
The Baffin Island Reindeer Experiment Manuscript at Dartmouth College Library
Animal migration
Biogeography
Reindeer
Population ecology
Population genetics | Reindeer distribution | [
"Biology"
] | 5,878 | [
"Ethology",
"Biogeography",
"Animal migration",
"Behavior"
] |
63,007,621 | https://en.wikipedia.org/wiki/Geometric%20Folding%20Algorithms | Geometric Folding Algorithms: Linkages, Origami, Polyhedra is a monograph on the mathematics and computational geometry of mechanical linkages, paper folding, and polyhedral nets, by Erik Demaine and Joseph O'Rourke. It was published in 2007 by Cambridge University Press ().
A Japanese-language translation by Ryuhei Uehara was published in 2009 by the Modern Science Company ().
Audience
Although aimed at computer science and mathematics students, much of the book is accessible to a broader audience of mathematically-sophisticated readers with some background in high-school level geometry.
Mathematical origami expert Tom Hull has called it "a must-read for anyone interested in the field of computational origami".
It is a monograph rather than a textbook, and in particular does not include sets of exercises.
The Basic Library List Committee of the Mathematical Association of America has recommended this book for inclusion in undergraduate mathematics libraries.
Topics and organization
The book is organized into three sections, on linkages, origami, and polyhedra.
Topics in the section on linkages include
the Peaucellier–Lipkin linkage for converting rotary motion into linear motion,
Kempe's universality theorem that any algebraic curve can be traced out by a linkage,
the existence of linkages for angle trisection,
and the carpenter's rule problem on straightening two-dimensional polygonal chains.
This part of the book also includes applications to motion planning for robotic arms, and to protein folding.
The second section of the book concerns the mathematics of paper folding, and mathematical origami. It includes the NP-completeness of testing flat foldability,
the problem of map folding (determining whether a pattern of mountain and valley folds forming a square grid can be folded flat),
the work of Robert J. Lang using tree structures and circle packing to automate the design of origami folding patterns,
the fold-and-cut theorem according to which any polygon can be constructed by folding a piece of paper and then making a single straight cut,
origami-based angle trisection,
rigid origami,
and the work of David A. Huffman on curved folds.
In the third section, on polyhedra, the topics include polyhedral nets and Dürer's conjecture on their existence for convex polyhedra, the sets of polyhedra that have a given polygon as their net, Steinitz's theorem characterizing the graphs of polyhedra, Cauchy's theorem that every polyhedron, considered as a linkage of flat polygons, is rigid, and Alexandrov's uniqueness theorem stating that the three-dimensional shape of a convex polyhedron is uniquely determined by the metric space of geodesics on its surface.
The book concludes with a more speculative chapter on higher-dimensional generalizations of the problems it discusses.
References
External links
Authors' web site for Geometric Folding Algorithms including contents, errata, and advances on open problems
Linkages (mechanical)
Paper folding
Polyhedra
Computational geometry
Mathematics books
2007 non-fiction books
2009 non-fiction books | Geometric Folding Algorithms | [
"Mathematics"
] | 631 | [
"Recreational mathematics",
"Computational geometry",
"Computational mathematics",
"Paper folding"
] |
63,008,623 | https://en.wikipedia.org/wiki/Conical%20screw%20compressor | The relatively recently developed conical screw compressor is a type of rotary-screw compressor using a different topology from the typical dual-screw type. In effect it can be thought of as a conical spiral extension of a gerotor, although the exact geometry is somewhat different due to the angular offset. Because of this it does not have the inherent "blow-hole" leakage path which in typical screw compressors is responsible for significant leakage through the assembly and makes low-speed operation impractical. This theoretically allows much smaller rotors to have practical efficiency since at smaller sizes the leakage area does not become as large a portion of the pumping area as in straight screw compressors. In conjunction with the decreasing diameter of the cone shaped rotor this also allows much higher compression ratios to be achieved in a single stage.
A significant impediment to production is the machining of the outer rotor to the tolerances required. Although the inner rotor can be manufactured with precise CNC machines using common methods, the outer rotor presents significant difficulties due to the restricted access to the interior for precision tooling, and assembling the outer rotor from easier to machine segments presents its own problems. The cost of units is currently very high, but development is ongoing, development is primarily being performed by VERT Rotors who hold patents on this topology.
References
Gas compressors | Conical screw compressor | [
"Chemistry"
] | 274 | [
"Gas compressors",
"Turbomachinery"
] |
63,008,742 | https://en.wikipedia.org/wiki/Agreement%20Concerning%20Cooperation%20in%20the%20Exploration%20and%20Use%20of%20Outer%20Space%20for%20Peaceful%20Purposes | The Agreement Concerning Cooperation in the Exploration and Use of Outer Space for Peaceful Purposes was an agreement between the United States of America (USA) and the Union of Soviet Socialist Republics (USSR) which established a legal framework for the Apollo-Soyuz Test Project (ASTP) and refined the means and methods for sharing data between these two parties. It was written in the days leading up to May 24, 1972. Having been agreed upon months earlier, it was signed by US President Richard Nixon and USSR. Premier A. N. Kosygin in Moscow during a three-day state visit. This agreement was of particular significance as it furthered efforts towards cooperation in space between the US and the USSR. during the Cold War.
Key points
The Agreement enumerates areas in which the US and the USSR. would cooperate, notably exploration, space meteorology, environmental sciences, celestial bodies, and space medicine. It describes the means to accomplish these goals, listing among other things, "delegations [and] meetings of scientists and specialists of both countries."
It also broadly outlines the goals and time frame of the ASTP, stating that "[t]he parties have agreed to carry out projects for developing compatible rendezvous and docking systems [...] in order to enhance the safety of manned flight in space and to provide the opportunity for conducting joint scientific experiments." The agreement gives a tentative date and method for the implementation of the mission, describing "the docking of a United States Apollo-type spacecraft and a Soviet Soyuz-type spacecraft with visits of astronauts in each other's spacecraft."
Though the Soviets wanted to include clauses concerning communication satellites, the State Department could not agree to this as the United States' government does not control this industry.
Background and history
Though the Americans shrouded preliminary efforts to draft this agreement in secrecy to the point that it was being treated as "semi-clandestine," the Soviets had no such reservations; indeed, NASA officials found news of one of their upcoming meetings on the front page of the New York Times.
In The Partnership: A History of the Apollo-Soyuz Test Project by Edward C. Ezell and his wife, Linda Newman Ezell, the agreement's inception is narrated: the USSR only shared its drafts "a week before the Summit", leading to frantic scrambling on the part of the US State Department to finish theirs, working "until the middle of the night."
US President Nixon and USSR. Premier Kosygin signed the Agreement at 6:00 p.m. Moscow time on July 24, 1972.
References
Space exploration
Apollo program
Soyuz program
1972 in the United States
1972 in the Soviet Union
History of the United Nations
Apollo–Soyuz Test Project
Soviet Union–United States treaties
Space treaties | Agreement Concerning Cooperation in the Exploration and Use of Outer Space for Peaceful Purposes | [
"Astronomy"
] | 553 | [
"Space exploration",
"Outer space"
] |
63,011,965 | https://en.wikipedia.org/wiki/Valuation%20%28geometry%29 | In geometry, a valuation is a finitely additive function from a collection of subsets of a set to an abelian semigroup.
For example, Lebesgue measure is a valuation on finite unions of convex bodies of Other examples of valuations on finite unions of convex bodies of are surface area, mean width, and Euler characteristic.
In geometry, continuity (or smoothness) conditions are often imposed on valuations, but there are also purely discrete facets of the theory. In fact, the concept of valuation has its origin in the dissection theory of polytopes and in particular Hilbert's third problem, which has grown into a rich theory reliant on tools from abstract algebra.
Definition
Let be a set, and let be a collection of subsets of A function on with values in an abelian semigroup is called a valuation if it satisfies
whenever and are elements of
If then one always assumes
Examples
Some common examples of are
the convex bodies in
compact convex polytopes in
convex cones
smooth compact polyhedra in a smooth manifold
Let be the set of convex bodies in Then some valuations on are
the Euler characteristic
Lebesgue measure restricted to
intrinsic volume (and, more generally, mixed volume)
the map where is the support function of
Some other valuations are
the lattice point enumerator , where is a lattice polytope
cardinality, on the family of finite sets
Valuations on convex bodies
From here on, let , let be the set of convex bodies in , and let be a valuation on .
We say is translation invariant if, for all and , we have .
Let . The Hausdorff distance is defined as
where is the -neighborhood of under some Euclidean inner product. Equipped with this metric, is a locally compact space.
The space of continuous, translation-invariant valuations from to is denoted by
The topology on is the topology of uniform convergence on compact subsets of Equipped with the norm
where is a bounded subset with nonempty interior, is a Banach space.
Homogeneous valuations
A translation-invariant continuous valuation is said to be -homogeneous if
for all and The subset of -homogeneous valuations is a vector subspace of McMullen's decomposition theorem states that
In particular, the degree of a homogeneous valuation is always an integer between and
Valuations are not only graded by the degree of homogeneity, but also by the parity with respect to the reflection through the origin, namely
where with if and only if for all convex bodies
The elements of and are said to be even and odd, respectively.
It is a simple fact that is -dimensional and spanned by the Euler characteristic that is, consists of the constant valuations on
In 1957 Hadwiger proved that (where ) coincides with the -dimensional space of Lebesgue measures on
A valuation is simple if for all convex bodies with Schneider in 1996 described all simple valuations on : they are given by where is an arbitrary odd function on the unit sphere and is the surface area measure of In particular, any simple valuation is the sum of an - and an -homogeneous valuation. This in turn implies that an -homogeneous valuation is uniquely determined by its restrictions to all -dimensional subspaces.
Embedding theorems
The Klain embedding is a linear injection of the space of even -homogeneous valuations, into the space of continuous sections of a canonical complex line bundle over the Grassmannian of -dimensional linear subspaces of Its construction is based on Hadwiger's characterization of -homogeneous valuations. If and then the restriction is an element and by Hadwiger's theorem it is a Lebesgue measure.
Hence
defines a continuous section of the line bundle over with fiber over equal to the -dimensional space of densities (Lebesgue measures) on
Theorem (Klain). The linear map is injective.
A different injection, known as the Schneider embedding, exists for odd valuations. It is based on Schneider's description of simple valuations. It is a linear injection of the space of odd -homogeneous valuations, into a certain quotient of the space of continuous sections of a line bundle over the partial flag manifold of cooriented pairs Its definition is reminiscent of the Klain embedding, but more involved. Details can be found in.
The Goodey-Weil embedding is a linear injection of into the space of distributions on the -fold product of the -dimensional sphere. It is nothing but the Schwartz kernel of a natural polarization that any admits, namely as a functional on the -fold product of the latter space of functions having the geometric meaning of differences of support functions of smooth convex bodies. For details, see.
Irreducibility Theorem
The classical theorems of Hadwiger, Schneider and McMullen give fairly explicit descriptions of valuations that are homogeneous of degree and But for degrees very little was known before the turn of the 21st century. McMullen's conjecture is the statement that the valuations
span a dense subspace of McMullen's conjecture was confirmed by Alesker in a much stronger form, which became known as the Irreducibility Theorem:
Theorem (Alesker). For every the natural action of on the spaces and is irreducible.
Here the action of the general linear group on is given by
The proof of the Irreducibility Theorem is based on the embedding theorems of the previous section and Beilinson-Bernstein localization.
Smooth valuations
A valuation is called smooth if the map from to is smooth. In other words, is smooth if and only if is a smooth vector of the natural representation of on The space of smooth valuations is dense in ; it comes equipped with a natural Fréchet-space topology, which is finer than the one induced from
For every (complex-valued) smooth function on
where denotes the orthogonal projection and is the Haar measure, defines a smooth even valuation of degree It follows from the Irreducibility Theorem, in combination with the Casselman-Wallach theorem, that any smooth even valuation can be represented in this way. Such a representation is sometimes called a Crofton formula.
For any (complex-valued) smooth differential form that is invariant under all the translations and every number integration over the normal cycle defines a smooth valuation:
As a set, the normal cycle consists of the outward unit normals to The Irreducibility Theorem implies that every smooth valuation is of this form.
Operations on translation-invariant valuations
There are several natural operations defined on the subspace of smooth valuations The most important one is the product of two smooth valuations. Together with pullback and pushforward, this operation extends to valuations on manifolds.
Exterior product
Let be finite-dimensional real vector spaces.
There exists a bilinear map, called the exterior product,
which is uniquely characterized by the following two properties:
it is continuous with respect to the usual topologies on and
if and where and are convex bodies with smooth boundary and strictly positive Gauss curvature, and and are densities on and then
Product
The product of two smooth valuations is defined by
where is the diagonal embedding. The product is a continuous map
Equipped with this product, becomes a commutative associative graded algebra with the Euler characteristic as the multiplicative identity.
Alesker-Poincaré duality
By a theorem of Alesker, the restriction of the product
is a non-degenerate pairing. This motivates the definition of the -homogeneous generalized valuation, denoted as topologized with the weak topology. By the Alesker-Poincaré duality, there is a natural dense inclusion
Convolution
Convolution is a natural product on For simplicity, we fix a density on to trivialize the second factor. Define for fixed with smooth boundary and strictly positive Gauss curvature
There is then a unique extension by continuity to a map
called the convolution.
Unlike the product, convolution respects the co-grading, namely if then
For instance, let denote the mixed volume of the convex bodies If convex bodies in with a smooth boundary and strictly positive Gauss curvature are fixed, then
defines a smooth valuation of degree The convolution two such valuations is
where is a constant depending only on
Fourier transform
The Alesker-Fourier transform is a natural, -equivariant isomorphism of complex-valued valuations
discovered by Alesker and enjoying many properties resembling the classical Fourier transform, which explains its name.
It reverses the grading, namely and intertwines the product and the convolution:
Fixing for simplicity a Euclidean structure to identify we have the identity On even valuations, there is a simple description of the Fourier transform in terms of the Klain embedding: In particular, even real-valued valuations remain real-valued after the Fourier transform.
For odd valuations, the description of the Fourier transform is substantially more involved. Unlike the even case, it is no longer of purely geometric nature. For instance, the space of real-valued odd valuations is not preserved.
Pullback and pushforward
Given a linear map there are induced operations of pullback and pushforward The pullback is the simpler of the two, given by It evidently preserves the parity and degree of homogeneity of a valuation.
Note that the pullback does not preserve smoothness when is not injective.
The pushforward is harder to define formally. For simplicity, fix Lebesgue measures on and The pushforward can be uniquely characterized by describing its action on valuations of the form for all and then extended by continuity to all valuations using the Irreducibility Theorem. For a surjective map
For an inclusion choose a splitting Then
Informally, the pushforward is dual to the pullback with respect to the Alesker-Poincaré pairing: for and
However, this identity has to be carefully interpreted since the pairing is only well-defined for smooth valuations. For further details, see.
Valuations on manifolds
In a series of papers beginning in 2006, Alesker laid down the foundations for a theory of valuations on manifolds that extends the theory of valuations on convex bodies. The key observation leading to this extension is that via integration over the normal cycle (), a smooth translation-invariant valuation may be evaluated on sets much more general than convex ones. Also () suggests to define smooth valuations in general by dropping the requirement that the form be translation-invariant and by replacing the translation-invariant Lebesgue measure with an arbitrary smooth measure.
Let be an n-dimensional smooth manifold and let be the co-sphere bundle of that is, the oriented projectivization of the cotangent bundle.
Let denote the collection of compact differentiable polyhedra in The normal cycle of which consists of the outward co-normals to is naturally a Lipschitz submanifold of dimension
For ease of presentation we henceforth assume that is oriented, even though the concept of smooth valuations in fact does not depend on orientability. The space of smooth valuations on consists of functions of the form
where and can be arbitrary.
It was shown by Alesker that the smooth valuations on open subsets of form a soft sheaf over
Examples
The following are examples of smooth valuations on a smooth manifold :
Smooth measures on
The Euler characteristic; this follows from the work of Chern on the Gauss-Bonnet theorem, where such and were constructed to represent the Euler characteristic. In particular, is then the Chern-Gauss-Bonnet integrand, which is the Pfaffian of the Riemannian curvature tensor.
If is Riemannian, then the Lipschitz-Killing valuations or intrinsic volumes are smooth valuations. If is any isometric immersion into a Euclidean space, then where denotes the usual intrinsic volumes on (see below for the definition of the pullback). The existence of these valuations is the essence of Weyl's tube formula.
Let be the complex projective space, and let denote the Grassmannian of all complex projective subspaces of fixed dimension The function
where the integration is with respect to the Haar probability measure on is a smooth valuation. This follows from the work of Fu.
Filtration
The space admits no natural grading in general, however it carries a canonical filtration
Here consists of the smooth measures on and is given by forms in the ideal generated by where is the canonical projection.
The associated graded vector space is canonically isomorphic to the space of smooth sections where denotes the vector bundle over such that the fiber over a point is the space of -homogeneous smooth translation-invariant valuations on the tangent space
Product
The space admits a natural product. This product is continuous, commutative, associative, compatible with the filtration:
and has the Euler characteristic as the identity element. It also commutes with the restriction to embedded submanifolds, and the diffeomorphism group of acts on by algebra automorphisms.
For example, if is Riemannian, the Lipschitz-Killing valuations satisfy
The Alesker-Poincaré duality still holds. For compact it says that the pairing is non-degenerate. As in the translation-invariant case, this duality can be used to define generalized valuations. Unlike the translation-invariant case, no good definition of continuous valuations exists for valuations on manifolds.
The product of valuations closely reflects the geometric operation of intersection of subsets.
Informally, consider the generalized valuation The product is given by Now one can obtain smooth valuations by averaging generalized valuations of the form more precisely is a smooth valuation if is a sufficiently large measured family of diffeomorphisms. Then one has
see.
Pullback and pushforward
Every smooth immersion of smooth manifolds induces a pullback map If is an embedding, then
The pullback is a morphism of filtered algebras.
Every smooth proper submersion defines a pushforward map by
The pushforward is compatible with the filtration as well:
For general smooth maps, one can define pullback and pushforward for generalized valuations under some restrictions.
Applications in Integral Geometry
Let be a Riemannian manifold and let be a Lie group of isometries of acting transitively on the sphere bundle Under these assumptions the space of -invariant smooth valuations on is finite-dimensional; let be a basis. Let be differentiable polyhedra in Then integrals of the form are expressible as linear combinations of with coefficients independent of and :
Formulas of this type are called kinematic formulas. Their existence in this generality was proved by Fu. For the three simply connected real space forms, that is, the sphere, Euclidean space, and hyperbolic space, they go back to Blaschke, Santaló, Chern, and Federer.
Describing the kinematic formulas explicitly is typically a difficult problem. In fact already in the step from real to complex space forms, considerable difficulties arise and these have only recently been resolved by Bernig, Fu, and Solanes.
The key insight responsible for this progress is that the kinematic formulas contain the same information as the algebra of invariant valuations
For a precise statement, let
be the kinematic operator, that is, the map determined by the kinematic formulas (). Let
denote the Alesker-Poincaré duality, which is a linear isomorphism. Finally let be the adjoint of the product map The Fundamental theorem of algebraic integral geometry relating operations on valuations to integral geometry, states that if the Poincaré duality is used to identify with then :
.
See also
References
Bibliography
Geometry | Valuation (geometry) | [
"Mathematics"
] | 3,234 | [
"Geometry"
] |
62,080,720 | https://en.wikipedia.org/wiki/Arrol%20Gantry | The Arrol Gantry was a large steel structure built by Sir William Arrol & Co. at the Harland and Wolff shipyard in Belfast, Northern Ireland. It was built to act as overhead cranes for the building of the three Olympic-class liners.
Beardmore's gantry at Dalmuir
From 1900 to 1906, Arrol had constructed a shipyard for William Beardmore and Company at Dalmuir on the Clyde. This included a large gantry structure over the building berth. In 1906 it was used for the construction of the pre-dreadnought battleship , then the largest battleship launched on the Clyde.
The Beardmore gantry was long, wide and high, spanning a single building berth. The structure was of two long steel truss girders, supported on ten pairs of steel truss towers, braced by cross trusses above. Nine electric cranes were provided, with four jib cranes along each side girder, each having a 5-ton capacity and 30 foot jib. These were travelling cranes and could be moved along the girder, or grouped together to share a heavier lift. They were intended to place the main hull plates into position, with a dedicated gang for each crane, forming the plates and riveting them into place. A central 15 ton travelling gantry crane was also provided, for lifting machinery along the centreline of the hull.
The Belfast gantry would be very similar to this first gantry, although larger at long and spanning two building berths. The central girder between the berths allowed the addition of a larger cantilever crane.
The Beardmore gantry had used tapered towers, with size and strength proportional to the load upon them. The base of each was spread into a triangular arch, giving a more stable base and also allowing a railway line to be laid through the towers, bringing construction materials. For the Belfast gantry, the towers were more parallel, with straight inner faces. This allowed temporary working platforms to be attached and relocated upwards as a hull was constructed, giving an additional working space and easy access to the outside of the hull, even with heavy equipment. The access within the gantry was also improved, with long sloping walkways and electric lifts, rather than the previous slow and hazardous use of ladders.
Construction
The Belfast gantry was commissioned by the White Star Line and Harland and Wolff and built by Sir William Arrol & Co. in 1908. It was feet long, feet wide and feet high. It was an essential part of the infrastructure needed for the construction of the and and remained in use until it was demolished in the 1960s to create space for storage and car parking.
Before the Gantry, the northern end of the Queen's Island shipyard had four building slipways, each with gantry cranes above them. The cranes formed three crosswise gantries over each slip, with jib cranes working from each upright. To make space for the two new slipways, three of the old slipways were given up. No 1 slipway remained and continued in use, with its original gantries, and was used for building liners such as the . The two new slipways were numbered 2 & 3. There were nine slipways at Queen's Island before this, eight afterwards but the other remained numbered as 5...9 and there was no longer a No 4 slipway.
The Gantry was built on three rows, apart, of eleven steel truss towers with three large truss girders between them, and lighter crosswise Warren trusses above this. The large girders provided runways for a pair of 10-ton overhead cranes above each way and lighter 5-ton jib cranes from the sides. Along the centre line ran a light Titan crane, with a reach of 135 feet and able to carry a 3-ton load at full radius, and 5 tons closer in. The cranes were electrically-powered and built by Stothert & Pitt of Bath. Access to the high girders was provided by three long ramps and also electric lifts for the shipyard workers. As Harland and Wolff were primarily a commercial yard, there was no need for the huge Titan cranes being built at this time for the naval shipyards of the Clyde, where heavy lifts of armour plate, or even entire turrets, were needed.
Olympic-class liners
Olympic and Titanic were built together, with Olympic in the No 2 slipway. Olympic was launched first, in October 1910, with Titanic seven months later. To provide better photographs against the steelwork of the gantry, Olympic's hull was painted white during building, then repainted after launch. Titanic was painted in White Star's black hull livery from the outset. was then constructed on the Olympic ways.
World War I
At the outbreak of World War I, Harland and Wolff were still engaged in building passenger liners and the Belgian Red Star Line's 27,000 ton was almost completed on the adjacent No 1 way. had been launched from the No 2 way in July, a fortnight before the outbreak of war. A further liner, yard number 470, had been laid down there, but work had hardly started.
14 inch monitors
When the Royal Navy wished to build the 14 inch monitors as coastal bombardment ships, these building ways were the most immediately available. The monitors were fairly small, of around 6,000 tons and quite short, but they also had protective anti-torpedo bulges which gave them an extremely broad beam of . This would require equally wide building slips, which the Olympic slips could provide. The monitors were so short that the first two of them, Admiral Farragut and General Grant, could be built simultaneously on the same slipway. Farragut was launched on 15 April 1915, with Grant following on 29 April. The limited lifting capacity of the gantry's cranes required the 4-inch armour plate to be installed in particularly small pieces, compared to in a warship building yard. To install their US-supplied turrets, the hulls were taken to the COW yard on the Clyde.
12 inch monitors
A second group of monitors was also built. These were the 12 inch monitors and used guns taken from Majestic-class pre-dreadnought battleships. Although their 12-inch guns were now quite old, they had been sufficiently advanced over other guns at the time that they were still worth re-using. They had been the first British battleship main guns to use wire-wound construction and also the first to fire cordite propelling charges. As originally mounted, their elevation of 13½° only permitted a range of , which would leave the monitors within range of German coastal defences; with this increased to 30°, a range of was expected. Eight of these monitors were built, five by Harland and Wolff and four of them on slips 1 and 3 of the Queen's Island yard. Like the 14 inch monitors, these monitors had prominent anti-torpedo bulges to their hulls and required a wide building slip, but were short enough that two could be built simultaneously on the large liner slips.
Glorious
was laid down as a 'large, light cruiser' on 1 May 1915 and launched almost a year later on 20 April 1916.
A class of small 6 inch gun-armed monitors was also designed, to use the secondary armament removed from the Queen Elizabeth battleships. As the 14-inch monitors were now almost complete, it was hoped to build this whole class of five on a single large slipway. However the number 2 slipway was needed immediately for Glorious. Slipway 5, at the southern end of Queen's Island, was used instead to build three of them, working around the keel of the postponed , and the other two at the Workman, Clark yard across the water.
Terror
A second batch of 15 inch-armed monitors were built, with a more developed design than the earlier Marshals. Both were built by Harland and Wolff, at the Govan yard and on the third slip at Queen's Island. The Marshal monitors had been so unsuccessful, largely owing to their slow speed and their unreliable diesel engines, particularly for , that it was decided to remove their turrets for re-use on the new high-speed monitors. Ney's turret was removed at Elswick and the mount converted for greater elevation, then shipped to Belfast for installation by Harland and Wolff's floating crane.
Both of these monitors had a successful WWI career and served into WWII.
Berth plan
Disuse
The Gantry was in use into the 1960s, but the shipyard was then reorganised to provide a larger building space. Work on large ships then took place in a large dry dock at the end of the Musgrave channel on the south-eastern side of Queen's Island, served by a pair of Goliath cranes, Samson and Goliath.
A gallery at Titanic Belfast is dominated by a steel scaffold which stands high and alludes to the Arrol Gantry: however, the original gantry was nearly four times the height of the gallery's representation.
In popular culture
The Gantry dominated the skyline of Belfast and became an important local landmark, as Samson and Goliath would do again fifty years later. The poet
Louis MacNeice's autobiographical poem Carrickfergus describes his birthplace:
"I was born in Belfast between the mountain and the gantries
To the hooting of lost sirens and the clang of trams:"
This is somewhat anachronistic, as MacNeice was born just before the construction of the Gantry and his family had moved to nearby Carrickfergus before Olympic's launch.
Notes
References
History of Belfast
Cranes (machines)
RMS Titanic | Arrol Gantry | [
"Engineering"
] | 1,964 | [
"Engineering vehicles",
"Cranes (machines)"
] |
62,081,079 | https://en.wikipedia.org/wiki/Vicarious%20Hypothesis | The Vicarious Hypothesis, or hypothesis vicaria, was a planetary hypothesis proposed by Johannes Kepler to describe the motion of Mars. The hypothesis adopted the circular orbit and equant of Ptolemy's planetary model as well as the heliocentrism of the Copernican model. Calculations using the Vicarious Hypothesis did not support a circular orbit for Mars, leading Kepler to propose elliptical orbits as one of three laws of planetary motion in Astronomia Nova.
History
In 1600, Johannes Kepler met and began working with Tycho Brahe at Benátky, a town north of Prague where Brahe's new observatory was being built. Brahe assigned Kepler the task of modeling the motion of Mars using only data that Brahe had collected himself. Upon the death of Brahe in 1601, all of Brahe's data was willed to Kepler. Brahe's observational data was among the most accurate of his time, which Kepler used in the construction of the Vicarious Hypothesis.
Predecessors
Ptolemy
Claudius Ptolemy's planetary model consisted of a stationary earth surrounded by fixed circles, called deferents, which carried smaller, rotating circles called epicycles. Planets rotated on the epicycles as the epicycles traveled along the deferent. Ptolemy shifted the Earth away from the center of the deferent and introduced another point, the equant, equidistant to the deferent's center on the opposite side of the Earth.
The Vicarious Hypothesis uses a circular orbit for Mars and reintroduces a form of the equant to describe the motion of Mars with constant angular speed.
Copernicus
Nicolaus Copernicus broke from the geocentric model of Ptolemy by placing the Sun at the center of his planetary model. However, Copernicus retained circular orbits for the planets and added an orbit for the Earth, insisting that the Earth revolved around the Sun. The Sun was positioned off-center of the orbits but was still contained within all orbits.
Kepler adopted Copernican heliocentrism in the construction of the Vicarious Hypothesis so that his measurements of the distances to Mars were taken relative to the Sun.
Development
Kepler's construction of the Vicarious Hypothesis was based on a circular orbit for Mars and a heliocentric model for the planets. After receiving longitudinal observation data from Tycho Brahe, Kepler had twelve observations, two being his own, in which Mars was at opposition to the Sun. From these twelve observations, Kepler chose four to form the basis of the Vicarious Hypothesis because they had a relatively uniform distribution across his proposed circular orbit for Mars. In this sense, the Vicarious Hypothesis functions as a fit to observational data. Kepler used these four observations to determine the eccentricities of the Sun and equant of his proposed orbit. Unlike the Ptolemaic System, in which the Earth and equant were assumed equidistant to the center of the orbit, the Vicarious Hypothesis placed the equant where the time and location of the observation would match.
Using the Vicarious Hypothesis, Kepler determined the eccentricities of the Sun and equant to be 11,332 and 7,232 arbitrary units, respectively, for the Martian orbital radius of 100,000 units. Using these positions for the Sun and equant, the model constructed using the Vicarious Hypothesis agreed with the twelve observations within 2' of arc, a level of accuracy better than any other previous model. While the heliocentric longitudes of this model proved to be accurate, distances from the Sun to Mars, or latitudes of Mars, challenged the model. In his book, Astronomia Nova, Kepler determined that the eccentricity of the Sun, based on latitudinal oppositions, should be between a range of 8,000 and 9,943, conflicting with the eccentricity of 11,332 determined by the Vicarious Hypothesis. To accommodate the latitudinal data, Kepler modified the Vicarious Hypothesis to include a bisected eccentricity, making the Sun and equant equidistant to the center of the orbit. This resolved the error in the latitudes of Mars but introduced a longitudinal error of 8' of arc in some parts of the Mars orbit. While an 8' error still had better accuracy than previous models, corresponding to approximately one-fourth the diameter of the Moon, Kepler rejected the Vicarious Hypothesis because he did not believe it was accurate enough to model the true orbit of Mars.
Historical significance
The errors in latitude and longitude of the Mars orbit made Kepler realize that false assumptions were made using the Vicarious Hypothesis. In particular, Kepler amended the hypothesis to exclude the circular orbit. Kepler realized that he could fix the error by reducing the spread of the central region of the circular orbit, creating an ellipse. He used calculations previously made with the Vicarious Hypothesis to confirm the elliptical orbit for Mars. Kepler published his results in Astronomia Nova, in which he introduces the elliptical orbit for planets as his first law of planetary motion.
See also
Kepler orbit
History of astronomy
Orbital elements
References
Astronomy
Johannes Kepler
Mars
Planetary habitability
Space colonization | Vicarious Hypothesis | [
"Astronomy"
] | 1,049 | [
"nan"
] |
62,084,317 | https://en.wikipedia.org/wiki/Genome%20sequencing%20of%20endangered%20species | Genome sequencing of endangered species is the application of Next Generation Sequencing (NGS) technologies in the field of conservation biology, with the aim of generating life history, demographic and phylogenetic data of relevance to the management of endangered wildlife.
Background
In the context of conservation biology, genomic technologies such as the production of large-scale sequencing data sets via DNA sequencing can be used to highlight the relevant aspects of the biology of wildlife species for which management actions may be required. This may involve the estimation of recent demographic events, genetic variations, divergence between species and population structure. Genome-wide association studies (GWAS) are useful to examine the role of natural selection at the genome level, to identify the loci associated with fitness, local adaptation, inbreeding, depression or disease susceptibility. The access to all these data and the interrogation of genome-wide variation of SNP markers can help the identification of the genetic changes that influence the fitness of wild species and are also important to evaluate the potential respond to changing environments. NGS projects are expected to rapidly increase the number of threatened species for which assembled genomes and detailed information on sequence variation are available and the data will advance investigations relevant to the conservation of biological diversity.
Methodology
Non-computational methods
The traditional approaches in the preservation of endangered species are captive breeding and the private farming. In some cases those methods led to great results, but some problems still remain. For example, by inbreeding only few individuals, the genetic pool of a subpopulation remains limited or may decrease.
Phylogenetic analysis and gene family estimation
Genetic analyses can remove subjective elements from the determination of the phylogenetic relationship between organisms. Considering the great variety of information provided by living organisms, it is clear that the type of data will affect both the method of treatment and validity of the results: the higher the correlation of data and genotype, the greater is the validity likely to be. The data analysis can be used to compared different sequencing database and find similar sequences, or similar protein in different species. The comparison can be done using informatic software based on alignment to know the divergence between different species and evaluate the similarities.
NGS/Advanced sequencing methodologies
Since whole-genome sequencing is generally very data-intensive, techniques for reduced representation genomic approaches are sometimes used for practical applications. For example, restriction site-associated DNA sequencing (RADseq) and double digest RADseq are being developed. With those techniques researchers can target different numbers of loci. With a statistical and bioinformatic approach scientists can make considerations about big genomes, by just focusing on a small representative part of it.
Statistical and computational methods
While solving biological problems, one encounters multiple types of genomic data or sometimes an aggregate of same type of data across multiple studies and decoding such huge amount of data manually is unfeasible and tedious. Therefore, integrated analysis of genomic data using statistical methods has become popular. The rapid advancement in high throughput technologies allows researchers to answer more complex biological questions enabling the development of statistical methods in integrated genomics to establish more effective therapeutic strategies for human disease.
Genome crucial features
While studying the genome, there are some crucial aspects that should be taken in consideration. Gene prediction is the identification of genetic elements in a genomic sequence. This study is based on a combination of approaches: de novo, homology prediction, and transcription. Tools such as EvidenceModeler are used to merge the different results. Gene structure also have been compared, including mRNA length, exon length, intron length, exon number, and non-coding RNA.
Analysis of repeated sequences has been found useful in reconstructing species divergence timelines.
Application and case studies
Genomic approach in gender determination
In order to preserve a specie, knowledge of the mating system is crucial: scientists can stabilize wild populations through captive breeding, followed by the release in the environment of new individuals. This task is particularly difficult by considering the species with homomorphic sex chromosomes and a large genome. For example, in the case of amphibians, there are multiple transitions among male and/or female heterogamety. Sometimes even variation of sex chromosomes within amphibian populations of the same specie were reported.
Japanese giant salamander
The multiple transitions among XY and ZW systems that occur in amphibians determine the sex chromosome systems to be labile in salamanders populations. By understanding the chromosomal basis of sex of those species, it is possible to reconstruct the phylogenetic history of those families and use more efficient strategies in their conservation.
By using the ddRADseq method scientists found new sex-related loci in a 56 Gb genome of the family Cryptobranchidae. Their results support the hypothesis of female heterogamety of this species. These loci were confirmed through the bioinformatic analysis of presence/absence of that genetic locus in sex-determined individuals. Their sex was established previously by ultrasound, laparoscopy and measuring serum calcium level differences. The determination of those candidate sexual loci was performed so as to test hypotheses of both female heterogamety and male heterogamety. Finally to evaluate the validity of those loci, they were amplified through PCR directly from samples of known-sex individuals. This final step led to the demonstration of female heterogamety of several divergent populations of the family Cryptobranchidae.
Genomic approach in genetic variability
Dryas monkey and golden snub-nosed monkey
A recent study used whole-genome sequencing data to demonstrate the sister lineage between the Dryas monkey and vervet monkey and their divergence with additional bidirectional gene flow approximately 750,000 to approximately 500,000 years ago. With <250 remaining adult individuals, the study showed high genetic diversity and low levels of inbreeding and genetic load in the studied Dryas monkey individuals.
Another study used several techniques such as single-molecule real time sequencing, paired-end sequencing, optical maps, and high-throughput chromosome conformation capture to obtain a high quality chromosome assembly from already constructed incomplete and fragmented genome assembly for the golden snub-nosed monkey. The modern techniques used in this study represented 100-fold improvement in the genome with 22,497 protein-coding genes, of which majority were functionally annotated. The reconstructed genome showed a close relationship between the species and the Rhesus macaque, indicating a divergence approximately 13.4 million years ago.
Genomic approach in preservation
Plants
Plants species identified as PSESP ("plant species with extremely small population") have been the focus of genomic studies, with the aim of determining the most endangered populations. The DNA genome can be sequenced starting from the fresh leaves by doing a DNA extraction. The combination of different sequencing techniques together can be used to obtain a high quality data that can be used to assembly the genome. The RNA extraction is essential for the transcriptome assembly and the extraction process start from stem, roots, fruits, buds and leaves. The de novo genome assembly can be performed using software to optimize assembly and scaffolding. The software can also be used to fill the gaps and reduce the interaction between chromosome. The combination of different data can be used for the identification of orthologous gene with different species, phylogenetic tree construction, and interspecific genome comparisons.
Limits and future perspectives
The development of indirect sequencing methods has to some degree mitigated the lack of efficient DNA sequencing technologies. These techniques allowed researchers to increase scientific knowledge in fields like ecology and evolution. Several genetic markers, more or less well suited for the purpose, were developed helping researchers to address many issues among which demography and mating systems, population structures and phylogeography, speciational processes and species differences, hybridization and introgression, phylogenetics at many temporal scales. However, all these approaches had a primary deficiency: they were all limited only to a fraction of the entire genome so that genome-wide parameters were inferred from a tiny amount of genetic material.
The invention and rising of DNA sequencing methods brought a huge contribution in increasing available data potentially useful to improve the field of conservation biology. The ongoing development of cheaper and high throughput allowed the production of a wide array of information in several disciplines providing conservation biologists a very powerful databank from which was possible to extrapolate useful information about, for example, population structure, genetic connections, identification of potential risks due to demographic changes and inbreeding processes through population-genomic approaches that rely on the detection of SNPs, indel or CNV. From one side of the coin, data derived from high throughput sequencing of whole genomes were potentially a massive advance in the field of species conservation, opening wide doors for future challenges and opportunities. On the other side all these data brought researchers to face two main issues. First, how to process all these information. Second, how to translate all the available information into conservation's strategies and practice or, in other words, how to fill the gap between genomic researches and conservation application.
Unfortunately, there are many analytical and practical problems to consider using approaches involving genome-wide sequencing. Availability of samples is a major limiting factor: sampling procedures may disturb an already fragile population or may have a big impact in individual animals itself putting limitations to samples' collection. For these reasons several alternative strategies where developed: constant monitoring, for example with radio collars, allow us to understand the behavior and develop strategies to obtain genetic samples and management of the endangered populations. The samples taken from those species are then used to produce primary cell culture from biopsies. Indeed, this kind of material allow us to grow in vitro cells, and allow us to extract and study genetic material without constantly sampling the endangered populations. Despite a faster and easier data production and a continuous improvement of sequencing technologies, there is still a marked delay of data analysis and processing techniques. Genome-wide analysis and big genomes studies require advances in bioinformatics and computational biology. At the same time improvements in the statistical programs and in the population genetics are required to make better conservation strategies. This last aspect work in parallel with prediction strategies which should take in consideration all features that determine fitness of a species.
See also
Endangered species
References
Biotechnology
Conservation biology
Ecology
Endangered species
Extinction events
Genomics techniques | Genome sequencing of endangered species | [
"Chemistry",
"Biology"
] | 2,099 | [
"Genetics techniques",
"Evolution of the biosphere",
"Genomics techniques",
"Biota by conservation status",
"Ecology",
"Extinction events",
"Biotechnology",
"Molecular biology techniques",
"nan",
"Conservation biology",
"Endangered species"
] |
62,084,336 | https://en.wikipedia.org/wiki/Ancient%20pathogen%20genomics | Ancient pathogen genomics is a scientific field related to the study of pathogen genomes recovered from ancient human, plant or animal remains. Ancient pathogens are microorganisms, now extinct, that in the past centuries caused several epidemics and deaths worldwide. Their genome, referred to as ancient DNA (aDNA), is isolated from the burial's remains (bones and teeth) of victims of the pandemics caused by these pathogens.
The analysis of the genomic features of ancient pathogen genomes allows researchers to understand the evolution of modern microbial strains that can hypothetically generate new pandemics or outbreaks. The analysis of aDNA is carried out by bioinformatic tools and molecular biology techniques to compare ancient pathogens with the modern descendants. The comparison also provides phylogenetic information of these strains.
Reconstructing ancient pathogen genomes through NGS technologies
Pathogen DNA detection in ancient remains can be achieved with laboratory or computational methods. In both cases, the procedure starts with the extraction of DNA from ancient specimens. The laboratory methods are based on the construction of NGS libraries and the subsequent capture-based screening. Computational tools are used to map the reads obtained by NGS against a single- or multi-genome reference (targeted approach); alternatively, metagenomic profiling or taxonomic assignment of shotgun NGS reads methods can be applied (broad approach).
Isolating ancient DNA
The limited preservation and thus low abundance, the highly fragmented and damaged state and the presence of modern DNA contamination and environmental DNA background makes the retrieval of ancient DNA (aDNA) a challenging procedure.
In order to efficiently recover aDNA, DNA is generally isolated from tissues that contain a high quantity of aDNA, like bone and teeth, which are abundant in archaeological record. The preservation of pathogens across different anatomical elements is very variable according to the type of pathogen and its tissue tropism, its route of entry into the body and the resulting disease. Pathogens that cause chronic infections in their hosts typically produce diagnostic bone changes as opposed to acute blood-borne infections. Therefore, for that infections that have caused the death of the host in the acute phase, the preferred sampling material is the inner chamber of the teeth since this is a tissue that is highly vascularized during life.
aDNA is characterised by damages that are accumulated over the course of time: the evaluation of DNA 'damage pattern' through computational tools is useful to authenticate ancient pathogen DNA since the same pattern is not found in modern contaminants.
The most represented chemical damage that affects the DNA post-mortem is the hydrolytic deamination of cytosines, converting them in uracils, which are then read as thymines. Due to this reaction, ancient DNA contains an unexpected proportion of cytosine to thymine transitions, in particular at the ends of the molecules. Other common DNA modifications, besides the deamination of cytosine into thymine (this occurs when cytosines were methylated), is the presence of abasic sites and single-strand breaks.
aDNA is extensively fragmented (most of the fragments are less than 100 base pairs long): this tendency can be used as a quantitative measure of authenticity, as modern contaminant molecules are expected to be longer. To exploit this characteristic feature of ancient DNA, improved silica-based extraction protocols with modified volume and composition of the DNA-binding buffer were introduced.
Construction of DNA libraries
In order to be sequenced with second generation sequencing methods, template molecules have to be modified through ligation of adaptors. Both the steps of library construction and the PCR amplification that follows are subject to errors. In particular, adaptor binding biases can occur and the relative efficacy of PCR enzymes in amplifying the construct can be variable.
There are three most common types of aDNA libraries. The double-stranded DNA library uses double-stranded DNA templates and firstly requires a step for the repair of the ends of aDNA fragments. Then, fragments are ligated to double-stranded adaptors and the resultant nicks are filled in. This method has some limitations, like the presence of a fraction of constructs that do not contain both the different adaptors and the possible formation of adaptor dimers.
To overcome this latter problem, a method for the construction of an A-tailed library was developed. In this method, aDNA is end-repaired and then an adenine residue is added to the 3' ends of the strands, which can facilitate the ligation of the template with adaptors that contain a tailor of thymine. Furthermore, the use of these T-tailed adaptors prevents the formation of adaptor dimers. The type of adaptor that is typically used is double-stranded and has a Y shape, which means that it has a region located at the T-tailed end where it is complementary and a region at the other end where it is non-complementary. The use of this type of adaptors allows to generate a template of aDNA flanked by different non-complementary adaptor sequences at each end that are useful for the unidirectional sequencing.
Another strategy is based on the use of single-stranded DNA libraries. In this method, DNA is first denatured to generate a single strand through heat and then ligated to a single-stranded biotinylated adaptor. The DNA strand is then used as a template by a DNA-polymerase which produces the complementary strand. Subsequently, a second adaptor is ligated at the 3' end of the complementary strand and the full construct is amplified through PCR and then sequenced. The purification step is performed using streptavidin-coated paramagnetic beads which allow minimising the DNA loss during this phase of the procedure.
Enriching libraries for aDNA
Different methods (called enrichment methods) have been developed to improve accessibility to endogenous DNA in ancient remains. These approaches can mainly be divided into three types: those used during library construction, by preferentially incorporating aDNA fragments characterised by the high level of damage, those applied after library construction, by separating exogenous and endogenous fractions through annealing to pre-defined sets of probes (in solution or on microarrays), or those based on targeted digestion of environmental microbial DNA using restriction enzymes and primer extension capture (PEC).
Selective uracil enrichment
During the construction of the library, the ssDNA fragments are bound through a biotinylated adaptor to streptavidin-coated beads. In the polymerase extension step, the DNA strand complementary to the original template is generated. In this kind of enrichment, the constructs undergo phosphorylation at the 5' end, to enable the ligation of a non-phosphorylated adaptor (ligation between the 3' end of the adaptor and the 5' end of the newly synthesized strand). DNA is then treated with uracil DNA glycosylase (UDG) and endonuclease VIII (USER mix): UDG generates abasic sites at cytosine that were deaminated into uracils post-mortem, endo VIII cuts at the resulting abasic site. This cleavage generates new 3' termini, which are then dephosphorylated, resulting in 3'OH ends that can be used as starting points for a new step of extension. This results in the elongation of the damaged strand, from the damaged region towards the bounded bead: while the new DNA molecule is synthesised, the original fragment is displaced. As a result, the dsDNA molecules newly formed no longer contain the adaptor bound to the beads, leaving in the supernatant a dsDNA library of the strands that originally harboured deaminated cytosines, available for further amplification and sequencing. The undamaged DNA template fraction remains attached to the paramagnetic beads.
Extension-free target enrichment in solution
This approach is based on in solution target-probe hybridization to screen for only a single microorganism, after the construction of the library. It is a species-specific assay that requires heat denaturation of DNA libraries and the construction of a probe DNA library using long-range PCR if fresh DNA material from closely related species is available, or through custom design and synthesis of oligonucleotides. This method is useful when the microorganism to target is known, for example, when the hypothesis exists for the causative agent of an epidemic or in presence of skeletal lesions in the studied individuals.
Solid-phase target enrichment
Another enriching strategy applied after constructing the library is the direct application of microarrays. They are applied for a wide laboratory-based pathogen screening that searches simultaneously for various pathogenic microorganisms. This kind of approach is favourable for those pathogens that leave no physical skeletal evidence and whose presence cannot be easily hypothesized a priori. The probes are designed to represent conserved or unique regions from a range of pathogenic viruses, parasites or bacteria.
Since microarrays contain sequences derived from modern strains of ancient pathogens, the limits of this method are the poor detection of the most divergent genomic regions and the omission of regions with important genomic rearrangements or unknown additional plasmids.
Whole-genome enrichment
The whole-genome in-solution capture (WISC) allows the characterization of the entire genome sequence of ancient individuals. This technique is based on the use of a genome-wide biotinylated RNA probe library generated through in vitro transcription of fresh modern DNA extracts from species closely related to the target aDNA sample. The heat-denatured aDNA library is then annealed to the RNA probes. To improve stringency and reduce enrichment for highly repetitive regions, low-complexity DNA and adaptor-blocking RNA oligonucleotides are added. The library fraction of interest in then recovered through elution from streptavidin-coated paramagnetic beads (to which the RNA probes are bound).
Computational analysis
The analysis of sequence data obtained by NGS relies on the same computational approaches used for modern DNA, with some peculiarities. A widely used tool to align reads from aDNA against reference genomes is the PALEOMIX package, which can quantify DNA damage levels through mapDamage2 and perform phylogenomic and metagenomic analyses. It is important to consider that the alignment will always exhibit substantial fractions of nucleotides mismatched that do not result from sequencing errors or polymorphisms but from the presence of damaged bases. For this reason, the acceptance threshold for read-to-reference edit distance should be chosen according to the phylogenetic distance to the reference genome. Probabilistic aligners that take into account the damage pattern of aDNA have been developed to improve alignments.
MALT
Studies of the ancient DNA of pathogens is restricted to skeletal collections that change their appearance as a result of infections. A pathogen linked to a known epidemiological context is identified through screening without prior knowledge of its presence. Methods include broad-spectrum molecular approaches focused on pathogen detection via fluorescence hybridization-based microarray technology, identification via DNA enrichment of certain microbial regions or computational screening of non-enriched sequence data against human microbiome data sets. These approaches offer improvements but remain biased in the bacterial taxa used for species-level assignments.
MEGAN alignment tool (MALT) is a new program for the fast alignment and taxonomic assignment method to the identification of ancient DNA. MALT is similar to BLAST as it computes local alignments between highly conserved sequences and references. MALT can also calculate semi-global alignments where reads are aligned end-to-end. All references, complete bacterial genomes, are contained in a database called National Center for Biotechnology Information (NCBI) RefSeq. MALT consists of two programs: malt-build and malt-run. Malt-build is used to construct an index for the given database of reference sequences. Instead, malt-run is used to align a set of query sequences against the reference database. The program then computes the bit-score and the expected value (E-value) of the alignment and decides whether to keep or discard the alignment depending on user-specified thresholds for the bit-score, the E-value or the per cent identity. The bit-score is the requires size of a sequence database in which the current match could be found just by chance. The higher the bit-score, the better the sequence similarity. E-value is the number of expected hits of similar quality (score) that could be found just by chance. The smaller is the E-value, the better is the match.
MALT allows the screening of non-enriched sequence data in the search for unknown candidate bacterial pathogens that are involved in past disease outbreaks and for the exclusion of the environmental bacterial background. MALT is very important because it offers the advantage of genome-level screening without selection of a particular target organism, avoiding errors that are common to other screening approaches. To authenticate the candidate taxonomic assignments complete alignments are needed, but the target DNA is often present in a low amount so a small number of a marked region may not be sufficient for identification. This approach can detect only bacterial DNA and viral DNA, so it is not possible to identify other infectious agents that may be present in a population. This method is useful for studies dealing with the identification of pathogens responsible for ancient and modern disease, especially in cases for which candidate organisms are not known a priori.
Applications
Ancient pathogen genomics as a tool against future epidemics
One interesting application of the different sequencing techniques available nowadays is the investigation of historical disease outbreaks to provide an answer to important and long-standing questions in epidemiology, pathogen evolution and also human history.
So, much effort is spent to find more and more information about the aetiology of infectious diseases of historical importance, such as plague and the cocoliztli epidemic, to describe the geographic spread of viruses and to try defining the pathogenic mechanism of these infectious agents that are actually active elements of the evolutionary process. Today Y.pestis and S. enterica seem to be harmless to humans, but scientists are still interested in the long-term tracing of genetic adaptation of these bacteria and accurate quantification of rates of their evolutionary change. This is because they can extract from this knowledge of the past the right ideas to develop a strategy against future epidemics.
Being perfectly aware of the fact that bacteria and viruses are one of the most variable elements in nature, prone to unlimited mutational events, and taking for granted that it is impossible to manage all the external factors that can influence the development of a pathogenic virus, nobody is talking about defeating a new possible outbreak of plague or any other infective agent of the past: here the aim is to define a strategy, a "guideline", to be more prepared when a new dangerous pathogen will come. The contribution of the environment in infections is to be defined and factors such as human migration, climate change, overcrowding in cities or animal domestication are some of the major causes that contribute to the emergence and spread of disease. Of course, these factors are unpredictable and this is a reason why researchers are trying to bring relevant information from the past, that can be useful, today and tomorrow. While they continue to develop strategies to defeat emerging threats using diagnostic, molecular and advanced tools, they are still looking back at how ancient pathogens have evolved and adapted through historical events. The more it's known about the genomic basis of virulence in historical diseases, the more it can be understood about the emergence and re-emergence of infectious diseases today and in the future.
Ancient infections and human evolution
The analyses of phylogenic relationships between the human host and viral pathogens suggest that many diseases have been coevolving with humans for millennia, since the very start of human history in Africa.
In particular, the long-term interaction with pathogens is considered a selection that can be very strong since not all the individuals could survive in touch with all infectious agents that they had met over the years: the natural selection by pathogens is implicated in the evolution of species. This interaction has been already used to track human population movements and to reconstruct human migration flows within and out of Africa.
A pretty new application and interpretation of this feature is using aDNA to better understand human evolution. Many tropical infections probably played a significant role in the human evolutionary process. The correlation between humans and viruses can be understood if it is seen as a "fight" that continues for millennia and that is not still won by anyone: when viruses have changed their features in order to be infective for the other "fighters", humans had to find a strategy to increase their fitness and survived among changes.
In this continuous challenge through the years, next to infective diseases and other illnesses afflicting modern human society, cancer recently represents one of the most enigmatical ailments. Scientists are investigating if neoplastic diseases are restricted to postindustrial human society or if their origins can be found further back in time, maybe into prehistory. The difficulty is that cancer, lethal and fast, leaves very few indications in skeletons in those cases that succumb to death shortly, and even no signs of existence at all, in the case of extraskeletal tumours. Anyway, the knowledge about the aetiology of cancer is incomplete and microorganisms are taking their part with the role of their infection: migration movements in the past could have brought with them viruses, so possible reservoir of tropical disease as well as predisposition to cancer. For this reason, molecular analytical techniques are applied to archaeological remains to study hominin evolution, but also to improve the research in understanding the epidemiology and aetiology of tumours. Information derived from the aDNA can be used to anchor pathogen mutations and reconstruct back from the presence of microorganisms the evolutionary process, it can be useful to develop new vaccines or to discover possible future pathogenic threats.
Past pandemics are much more than just ancient history
What happened in the past is not all history, there is something hidden that can still drive human genetic diversity and natural selection, something that went in contact with humankind hundreds of years ago but that can still have an impact on global human health. Since epidemics are one of the most frequent phenomena that have affected and potentially devastated human populations, it is important to detect, prevent and control potential infective agents. After all, archaeologists, geneticists, and medical scientists are concerned in exploring the influences of pathogens that can contribute, threatening or improving, human health and longevity.
Evolution and phylogenesis of Yersinia pestis
Yersinia pestis is a gram-negative bacterium and belongs to the family of Enterobatteriaceae. Its closest relatives are Yersinia pseudotuberculosis and Yersinia enterocolitica, which are environmental species.
They all possess the plasmid pCD1, which encodes for a type III secretory system. Among chromosomal protein-coding genes, their nucleotide genomic identity rates 97%. They are different in terms of their virulence potential and transmission mechanisms.
Y. pestis is not a human-adapted bacteria. Its main reservoirs are rodents (like marmots, mice, great gerbils, voles and prairie dogs) and it is transmitted to humans by the flea. One of the most studied vectors of this pathogen is Xenopsylla cheopis.
After the bite of an infected flea, the bacteria enter into the host organism and travel to the closest lymph node, where bacteria replicate causing the large swellings called buboes. Bacteria can also disseminate into the bloodstream (causing septicaemia) and to the lung (causing pneumonia). The pulmonary disease has a direct human-to-human transmission.
It has been determined that Y. pestis became so dangerous because of the acquisition of ymt (yersina murine toxin). This gene is present on the pMT1 plasmid and allowed the survival of the bacterium in the flea vector and facilitated colonization of the midgut in arthropod, giving rise to the past millennium large-scale pandemics.
Early evolution and divergence from Yersinia pseudotuberculosis
Y. pestis is distinguishable from the other two species because of its pathogenicity and transmission mechanism. These differences are given by two plasmids: pPCP1, that confer to the bacterium its invasive properties in humans and pMT1, which is involved in flea colonisation (along with some loss of function on bacterial chromosomal genes).
Samples dated on the Late Neolithic and Bronze Age allowed identifying a first genetic divergence between Y. pseudotuberculosis and Y. pestis ancestors. The characteristics that confer to Y. pestis its virulence were absent in these strains: they lack of ymt, a gene necessary to the colonization of the vector; also, they presented an active form of genes required for biofilm formation (inactive in the pathogen Y. pestis) and an active flagellin gene, that is an inducer of immune response (is a pseudogene in Y. pestis).
The comparison of a draft of the genome and the two plasmids (pCD1 and pMT1) with samples of Black Death victims (1348–1349) in the East Smithfield burial ground underlined a very high genetic conservation of the sequence: only 97 single-nucleotide differences over 660 years.
Y. pestis microevolution
The London 6330 individual strain owns mutations absent in other isolates of the same period (1348–1350): the reason may be either the presence of multiple strains circulating in Europe at the same time or the microevolution of one single strain during the pandemic.
Three major outbreaks of plague
There are three pandemic outbreaks of Y. Pestis:
The first is known as the Plague of Justinian, it first occurred in Egypt in 541-543 and then spread to Constantinople and neighbouring regions. It had outbreaks in Europe until 750 CE. Phylogenetic analysis showed that both genomes belong to a lineage that is extinct today and is closely related to strains from modern-day China, which suggest the possibility of an East Asian origin of the first pandemic.
The second pandemic is known as the Black Death or as Great Pestilence. It occurred in 1346–1352 in Europe and had a lot of resurgences of plague, it continued until the 18th century. It could be possible that in this pandemic there were two different strains of Y. pestis that entered the continent through different pulses.
The third pandemic started in China in 1860. It has a fast spread to other countries, due to the use of railways and steamships.
The strains associated with the Justinian Plague appear on a novel branch, which is phylogenetically distinct from the second and the third plague pandemics. The first strain of Y. pestis found during the second outbreak survives and give rise to modern branch 1 strains associated with the third pandemic outbreak.
The first plague bacteria and the second and third plague strain have a common ancestor.
Linkage between 2nd and 3rd pandemics
In a recent study, genomes of Y. pestis from three samples resumed in Barcelona (deceased between 1300 and 1420), Ellwangen (between 1486 and 1627) and Bolgar city (between 1298 and 1388). The date of death of the individuals analysed was determined thanks to radiocarbon dates; the last one was confirmed by the presence of a coin produced only after the year 1362. Of 223 samples from 178 individuals, only one for each site had a suitable amount of DNA and was finally selected for the whole genome sequencing of the bacillus (through a genome-capture assay, using as a draft Y. pseudotuberculosis genome and pMT1 and pCD1 from Y. pestis).
The alignment with a Y. pestis phylogeny tree created with previously known ancient genomes revealed an increase genetic diversity outside of China in comparison to what was previously thought; all the three new genomes mapped in Branch 1 and possess two SNPs associated to the Black Death (all the genomes of Y. pestis dated to the Black Death map in Branch 1). The Barcelona strain has no differences with the London strain; the two individuals from which the genome was obtained died of plague with a distance of some months (spring and autumn 1348) underlining the presence in Europe of a single wave of plague with low genetic diversity. The Ellwangen strain maps in a sub-branch of Branch 1 and is ancestral to a previously sequenced strain (L'Observance). It descends from the one circulating in London and Barcelona during the Black Death but also have additional mutations. It is therefore considered a lineage diverged from Branch 1 before the 16th century (Ellwangen outbreak) and with no known modern descendants.
In comparison with isolates from the Black Death, the Bolgar city strain presents:
p3 and p4, shared by the "London individual 6330";
p6, shared with all modern Branch 1 strains;
p7, unique of this strain;
The Bolgar City strain possesses SNPs associated to the Black Death and can be an evidence of a movement of plague towards east; These findings give credit to one of the models that try to explain the linkage between 2nd and 3rd pandemic: in this scenario, there was a single exit of plague to Europe (causing the Black Death) that after a radiation event, travelled eastward to establish in former soviet union and Asia, from which it spread in the 18th century to give raise to the 3rd pandemic.
Another hypothesis is that the 3rd pandemic's lineage may have been generated by a pre-existing genetic variability in Y. pestis strains in China: this hypothesis is actually supported by the correlation between following waves of the pandemic in Europe and climatic fluctuations that would have allowed its spread in the continent. This model can't explain the genetic diversity of the Black Death (four different lineages at least, that would have required the introduction from Asia of four different strains).
Again, there are two models that try to explain the multiple plague outbreaks in Europe following the black death:
Repeated introduction of plague from Asia. This scenario is compatible with the 2nd theory discussed before that sees a genetic variability of Y. pestis in China;
Presence in Europe of a reservoir (now extinct) that caused continue outbreaks until the 18th century;
Both models can be valid and nowadays we're not able to demonstrate one over the other. However, the Ellwangen strain genome sequenced in this study may be considered a proof of the second hypothesis due to the geographical position of the city that tends to exclude the possibility of an introduction of plague from eastward.
Modern Y. pestis strains
Sequencing of Y. pestis genomes allowed to discover a variation event preceding Black Death that gave rise to many strains that circulate today.
Salmonella enterica genomes analysis
A series of 16th epidemics in Mexico, called the "huey cocoliztli" in the native Nahuatl language, caused high mortality in indigenous Aztec population, leading to demographic collapse. These epidemics are considered among the worst epidemics in the history of Mexico and the causes have remained a mystery for over 500 years.
A group of scientists from Harvard and Max-Planck Institute published a study in the journal of Nature ecology and Evolution, and they suggest Salmonella enterica as a good candidate for the strong epidemic in Mexico during the 16th century. Many studies suggest that this bacterium has been introduced in the Indigenous populations by Europeans.
The group of scientists analyzed the aDNA extracted from the teeth of 24 skeletons buried in a cemetery in the city of Teposcolula-Yucundaa and they found in 10 of the 24 skeletons aDNA traces of Salmonella enterica. Also, to demonstrate that the bacterium was introduced in Mexico by the Europeans, they analyzed five individuals that were buried before the influx of Europeans. The results revealed that there was no evidence of Salmonella enterica in the pre-contact era.
Analysis of Salmonella enterica genomes
The scientists performed the extraction of the aDNA from the teeth of 24 indigenous individuals' remains from the contact era epidemic cemetery and of 5 individuals buried in the pre-contact era cemetery. The extraction was performed according to the protocol for aDNA extraction. The group of researchers examined, in parallel, also a soil sample of the cemeteries to get an overview of the environment microorganisms that could have penetrated the samples.
After the extraction, the genomes were sequenced using Illumina genome analyzer. Then, using a bioinformatic tool, called MALT, the researchers performed an analysis of metagenomic sequences data. This program lets the researchers align the extracted sequences with a reference without specifying a precise target. The researchers performed MALT run two times: one using the complete bacterial genomes that were available through NCBI (National Center for Biotechnology Information) RefSeq as a reference, and the second run was carried out using the full NCBI Nucleotide database to screen for viral DNA.
The result of the screening process was positive for the presence of Salmonella enterica DNA in 10 sequences up to 24 collected from the samples and three tooth sample had a high amount of reads assigned to S. enterica. In particular, the major S. enterica strain present in the samples is the S. Paratyphi C. This strain causes enteric fever in human individuals. In the pre-contact era samples, they did not find any evidence of S. enterica, supporting the hypothesis that S. enterica was not a local bacteria.
A further analysis was carried out to identify the classical pattern of damage of aDNA in the three positive tooth samples and this was conducted by mapping the data sets to the S. Paratyphy C genome reference. The results were positive and supported the thesis of S.enterica as the cause of cocolitzli.
To go in-depth with the analyses and confirm the thesis, the researchers conducted further experiments and computational analysis. They performed a whole-genome target array and in-solution hybridization capture using probes that include the modern S. enterica genome differences and using S. Paratyphi C as reference. The hybridization was successful for the ten positive samples, while the other samples resulted negative for the ancient DNA.
See also
aDNA
Yersinia pestis
Salmonella enterica
DNA microarray
DNA libraries
NGS
References
Pathogen genomics | Ancient pathogen genomics | [
"Biology"
] | 6,363 | [
"Molecular genetics",
"DNA sequencing",
"Pathogen genomics"
] |
62,084,344 | https://en.wikipedia.org/wiki/Human%20somatic%20variation | Human somatic variations are somatic mutations (mutations that occur in somatic cells) both at early stages of development and in adult cells. These variations can lead either to pathogenic phenotypes or not, even if their function in healthy conditions is not completely clear yet.
The term mosaic (from medieval Latin musaicum, meaning "work of the Muses") has been used since antiquity to refer to an artistic patchwork of ornamental stones, glass, gems, or other precious material. At a distance, the collective image appears as it would in a painting; only on close inspection do the individual components become recognizable. In biological systems, mosaicism implies the presence of more than one genetically distinct cell line in a single organism. Occurrence of this phenomenon not only can result in major phenotypic changes but also reveal the expression of otherwise lethal genetic mutations.
Genetic mutations involved in mosaicism may be due to endogenous factors, such as transposons and ploidy changes, or exogenous factors, such as UV radiation and nicotine.
Somatic mosaicism in healthy human tissues
Somatic mosaicism arises a result of somatic mutations: genomic (or even mitochondrial) alterations of different sizes ranging from a single nucleotide to chromosome gains or loss within somatic cells. These alterations within somatic cells begin at an early stage (pre-implantation or conception) and continue during aging, giving rise to phenotypic heterogeneity within cells, which may lead to the development of diseases such as cancer. Novel array based techniques for screening genome-wide copy number variants and loss of heterozygosity in single cells showed that chromosome aneuploidies, uniparental disomies, segmental deletions, duplications, and amplifications frequently occur during embryogenesis. Yet not all somatic mutations are propagated to the adult individual, due to the phenomenon of cell competition.
Genetic alterations involving gains or loss of entire chromosomes predominantly occur during anaphase stage of cell division. But these are uncommon in somatic cells because they are usually selected against due to their deleterious consequences. Somatic variations during embryonic development can be represented by monozygous twins since they carry different copy number profiles and epigenetic marks that keep on increasing with age.
Early research on somatic mutations in aging showed that deletions, inversion, and translocations of genetic material are common in aging mice and aging genomes tend to contain visible chromosomal changes, mitotic recombination, whole gene deletions, intragenic deletions, and point mutations. Other factors include the loss of methylation, increasing gene expression heterogeneity correlating to genomic abnormalities, and telomere shortening. It is uncertain if transcription-based DNA repair takes part in the maintaining of somatic mutations in aging tissues.
In some cells, the somatically acquired alterations can be reversed back to wild type alleles by reversion mosaicism. This can be due to endogenous mechanism such as homologous recombination, codon substitution, second-site suppressor mutations, DNA slippage, and mobile elements.
Somatic cancer-associated mutations in normal tissues
The advent of Next-Generation Sequencing technologies has increased the resolution of mutation detection and has led to the revelation that older individuals not only accumulate chromosomal alterations but also abundant mutations in cancer driver genes.
Age-associated accumulation of chromosomal alterations has been documented with a variety of cytogenetic approaches, from chromosome painting to single nucleotide polymorphism (SNP) arrays.
Numerous studies demonstrated that the clonal populations might lead to loss of organismal health through the functional decline of tissue and/or the promotion of disease processes, such as cancer. This is the reason why the aberrant clonal expansion (ACE) resulting from cancer-associated mutations are common in noncancerous tissue and accumulate with age. This is universal in most organisms and affects multiple tissues.
In the hematopoietic compartment mutations include both large structural chromosomal alterations and point mutations affecting cancer-associated genes. Some translocations appear to occur very early in life. The frequency of these events is low in people younger than 50 years (<0.5%), but this frequency rapidly increases to 2% to 3% of individuals in their 70s and 80s. This phenomenon was termed clonal hematopoiesis. A number of environmental factors, such as smoking, viral infections, and pesticide exposure, may contribute not only through mutation induction but also by modulation of clonal expansion.
Otherwise, the detection of somatic variants in normal solid tissues has historically proved difficult. The main reasons are the generally slower replicative index, clonally restrictive tissue architecture, difficulty of tissue access, and low frequency of mutation occurrence. Recently, the analysis of somatic mutations in benign tissues adjacent to tumors revealed that 80% of samples harbors clonal mutations, with increased frequency associated with older age, smoking, and concurrent mutations in DNA repair genes. With the advent of NGS, it has become increasingly clear that somatic mutations accumulate with aging in normal tissue, even in individuals who are cancer-free.
This suggested that clonal expansions driven by cancer genes are a near-universal feature of aging. NGS technologies revealed that the clonal expansions of cancer-associated mutations are very common condition in somatic tissues.
Human somatic variations in brain
Through several recent studies a prevalence of somatic variations, both in pathological and healthy nervous systems, has been highlighted.
Somatic aneuploidy such as SNVs (single-nucleotide variations) and CNVs (copy number variations) have been particularly observed and linked to brain disfunctions when arising in prenatal brain development; anyway those somatic aneuploidy have been observed in rates of 1,3-40%, potentially increasing with age and for this reason they have been proposed as a mechanism to generate normal genetic diversity among neurons.
The confirmation of that hypothesis has been obtained through studies of single-cell sequencing, which allow a direct assessment of single neuronal genomes, so that a systematic characterization of somatic aneuploidies and subchromosomal CNVs of these cells is possible. Using postmortem brains of both healthy and diseased humans it has been possible to study how CNVs change among these two groups. It emerged that somatic aneuploidies in healthy brains are quite rare, but somatic CNVs instead aren't.
These studies also showed that clonal CNVs exist in both pathological and healthy brains. This means that some CNVs can arise in early development without causing diseases, even though, when compared to the CNVs arising in other cell types such as lymphoblast, the brain's ones are more often private. This evidence could be given by the fact that, while lymphoblasts can generate clonal CNVs for a long period as they continue to proliferate, adult neurons do not replicate anymore, so the clonal CNVs they are carrying must have been generated in an early development stage.
Data highlighted a tendency in neurons for the loss, rather than for the gain of copies when compared to lymphoblasts. These differences could suggest that the molecular mechanisms of CNVs arising in that two cell types are completely different.
L1-associated mosaicism in brain cells
The retrotransposon LINE-1 (long interspersed element 1, L1) is a transposable element that has colonized the mammalian germline. L1 retrotransposition can happen also in somatic cells causing mosaicism (SLAVs – L1-associated variations) and in cancer. Retrotransposition is a copy and paste process in which the RNA template is retrotranscribed in DNA and integrated randomly in the genome. In humans there are around 500.000 copies of L1 and occupy 17% of genome. Its mRNA encodes for two proteins; one of them in particular has a reverse transcriptase and endonuclease activity that allows the retrotransposition in cis. Anyway most part of these copies are rendered immobile by mutations or 5’ truncation, leaving just about 80–100 mobile L1 per human genome and just about 10 are considered hot L1s so able to mobilize efficiently.
L1 transpose using a mechanism called TPRT (target primed reverse transcription) it's able to insert a L1 endonuclease motif, target site duplications (TSD) and a poly-A tail with a cis preference.
It has been seen in the past that there's L1 mobilization in neural progenitors during foetal and adult neurogenesis suggesting that the brain may be a L1 mosaicism hotspot. Moreover, some studies suggested that also non-dividing neurons can support L1 mobilization. This has been confirmed by single-cell genomic studies.
Single-cell paired-end sequencing experiments found out that SLAVs are present both in neurons and glia of hippocampus and frontal cortex. Any neural cell has a similar probability to contain a SLAV, suggesting that somatic variations are a random phaenomenon, not focused on a specific group of cells. SLAVs occurrence in the brain is estimated to be of 0.58–1 SLAVs per cell and to involve 44–63% of the brain cells.
Since experiments showed that a half of the analyzed SLAVs lack target site duplication (TSD), another kind of L1-associated variant might occur. In fact those sequences don't have an endonuclease activity, but still have endonuclease motifs so that they can be retrotransposed in trans.
An application of the study of somatic mosaicism in the brain could be the tracing of specific brain cells. Indeed, if the somatic L1 insertions occurs in a progenitor cell, the unique variant could be used to trace the progenitor cell's development, localization, and spreading through the brain. On the contrary, if the somatic L1 insertion occurs late in development, it will be present just in a single cell or in a small group of cells. Therefore, tracing somatic variations could be useful to understand at which point of development they have occurred. Further experiments are necessary to understand the role of somatic mosaicism in brain function, since small groups of cells or even single cells can affect network activity.
Human somatic variations and the immune system
Human somatic mutations (HSMs) are intensively exploited by the immune system for the production of antibodies. HSMs, recombination in particular, are indeed the reason why antibodies can identify an epitope with such high specificity and sensitivity.
Antibodies are encoded by B cells. Each antibody is composed of two heavy chains (IgH, encoded by IGH gene) and two light chains (IgL, encoded by either IGL or IGK gene). Each chain is then composed of a constant region (C) and a variable region (V). The constant region (C) on the heavy chain is important in the BCR signaling and determines the type of immunoglobuline (IgA, IgD, IgE, IgG, or IgM). The variable region (V) is responsible for the recognition of the target epitope and is the product of recombination processes in the related loci.
After exposure of an antigen, B cells start developing. B cells genome undergoes repeated recombination processing on the Ig genes until the recognition of the epitope is perfectioned. The recombination involves the IGH locus first and then the IGL and IGK loci. All IGL, IGK, and IGH genes are the product of the V(D)J recombination process. This recombination involves the variable (V), diversity (D) and joining (J) segments. All three segments (V, D, J) are involved in the formation of the heavy chain, while only V and J recombination products encode for the light chain.
The recombination between these regions allows the formation of 1012–1018 potential different sequences. However, this number is an overestimation, since many factors contribute to limit the diversity of the B cell repertoire, first of all the actual number of B cell in the organism.
Cardiac mosaicism
Somatic mosaicism has been noted in the heart. Sequencing suggested mosaic variation in the gap junction protein connexin in three patients out of 15 might contribute to atrial fibrillation although subsequent reports in larger numbers of patients found no examples among a large panel of genes. At Stanford, a team led by Euan Ashley demonstrated somatic mosaicism in the heart of a newborn presenting with life threatening arrhythmia. Family-based genome sequencing as well as tissue RNA sequencing and single cell genomics techniques were used to verify the finding. A model combining partial and ordinary differential equations with inputs from heterologous single channel electrophysiology experiments of the genetic variant recapitulated certain aspects of the clinical presentation.
See also
Antibody
Cancer
DNA sequencing
Mosaic (genetics)
Mutation
Retrotransposon
References
Cancer
Evolutionary biology
Genetics
Mutation
Nervous system | Human somatic variation | [
"Biology"
] | 2,761 | [
"Evolutionary biology",
"Organ systems",
"Genetics",
"Nervous system"
] |
62,084,354 | https://en.wikipedia.org/wiki/Clinical%20metagenomic%20sequencing | Clinical metagenomic next-generation sequencing (mNGS) is the comprehensive analysis of microbial and host genetic material (DNA or RNA) in clinical samples from patients by next-generation sequencing. It uses the techniques of metagenomics to identify and characterize the genome of bacteria, fungi, parasites, and viruses without the need for a prior knowledge of a specific pathogen directly from clinical specimens. The capacity to detect all the potential pathogens in a sample makes metagenomic next generation sequencing a potent tool in the diagnosis of infectious disease especially when other more directed assays, such as PCR, fail. Its limitations include clinical utility, laboratory validity, sense and sensitivity, cost and regulatory considerations.
Outside of clinical medicine, similar work is done to identify genetic material in environmental samples, such as ponds or soil.
Definition
Next-generation sequencing uses the techniques of metagenomics to identify and characterize the genome of bacteria, fungi, parasites, and viruses without the need for a prior knowledge of a specific pathogen directly from clinical specimens. The capacity to detect all the potential pathogens in a sample makes metagenomic next generation sequencing a potent tool in the diagnosis of infectious disease especially when other more directed assays, such as PCR, fail.
Laboratory workflow
A typical mNGS workflow consists of the following steps:
Sample acquisition: the most commonly used samples for metagenomic sequencing are blood, stool, cerebrospinal fluid (CSF), urine, or nasopharyngeal swabs. Among these, blood and CSF are the cleanest, having less background noise, while the others are expected to have a great amount of commensals and/or opportunistic infections and thus have more background noise. Samples should be collected with much caution as surgical specimens could be contaminated during handling of the biopsy; for example, lumbar punctures to obtain CSF specimens may be contaminated during the procedure.
RNA/DNA extraction: the DNA and the RNA of the sample is extracted by using an extraction kit. If there is a strong previous suspicion of the pathogen genome composition and since the amount of pathogen nucleic acid in more noise samples is overwhelmed by the RNA/DNA of other organisms, selecting an extraction kit of only RNA or DNA would be a more specific and convenient approach. Some commerciable available kits are for example RNeasy PowerSoil Total RNA kit (Qiagen), RNeasy Minikit (Qiagen), MagMAX Viral Isolation kit (ABI), Viral RNA Minikit (Qiagen).
Optimization strategies for library preparation: because of high levels of background noise in metagenomic sequencing, several target enrichment procedures have been developed that aim to increase the probability of capturing pathogen-derived transcripts and/or genomes. Generally there are two main approaches that can be used to increase the amount of pathogen signal in a sample: negative selection and positive enrichment.
Negative selection (background depletion or subtraction) targets and eliminates the host and microbiome genomic background, while aiming to preserve the nucleic acid derived from the pathogens of interest. Degradation of genomic background can be performed through broad-spectrum digestion with nucleases, such as DNase I for DNA background, or by removing abundant RNA species (rRNA, mtRNA, globin mRNA) using sequence-specific RNA depletion kits. Also CRISPR-Cas9-based approaches can be performed to target and deplete human mitochrondrial RNA for example. Generally, however, subtraction approaches lead to a certain degree of loss of the targeted pathogen genome, as poor recovery may occur during the cleanup.
Positive enrichment is used to increase pathogen signal rather than reducing background noise. This is commonly done through hybridization-based target capture by probes, which are used to pull out nucleic acid of interest for downstream amplification and sequencing. Panviral probes have been shown to successfully identify diverse types of pathogens in different clinical fluid and respiratory samples, and have been used for sequencing and characterization of novel viruses. However, the probe approach includes extra hybridization and cleanup steps, requiring higher sample input, increasing the risk of losing the target, and increasing the cost and hands-on time.
High-throughput sequencing: all the nucleic acids fragments of the library are sequenced. The sequencing platform to be used is chosen depending on different factors such as laboratory's research objectives, personal experience and skill levels. So far, the Illumina MiSeq system has proven to be the most commonly used platform for infectious disease research, pathogen surveillance, and pathogen discovery in research and public health. The instrument is compact enough to fit on a laboratory bench, has a fast runtime as compared to other similar platforms, and has a strong user support community. However, with further improvements of this technology and with additional error reduction and software stabilization, the MinION may be an excellent addition to the arsenal of current sequencing technologies for routine surveillance, especially in smaller laboratories with limited resources. For instance, the MinION was successfully used in the ZiBRA project for real-time Zika virus surveillance of mosquitoes and humans in Brazil, and in Guinea to perform real-time surveillance during the ongoing Ebola outbreak. In general, for limited resources IlluminaMiSeq, iSeq, Ion Torrent PGM, Oxford Nanopore, MinION are used. While for substantial resources Illumina NextSeq, NovaSeq, PacBio Sequel, Oxford Nanopore and PromethION are preferred. Moreover, for pathogen sequencing the use of controls is of fundamental importance ensuring mNGS assay quality and stability over time; PhiX is used as sequencing control, then the other controls include the positive control, an additional internal control (e.g., spiked DNA or other known pathogen) and a negative control (usually water sample).
Bioinformatic analysis: Whereas the sequencing itself has been made widely accessible and more user friendly, the data analysis and interpretation that follows still requires specialized bioinformatics expertise and appropriate computational resources. The raw data from a sequencing platform is usually cleaned, trimmed, and filtered to remove low-quality and duplicate reads. Removal of the host genome/transcriptome reads is performed to decrease background noise (e.g., host and environmental reads) and increase the frequency of pathogen reads. This step will also decrease downstream analysis time. Further background noise removal is achieved by mapping of sample reads to the reads from the negative control to ensure elimination of any contaminating reads, such as those associated with the reagents or sampling storage medium. The remaining reads are usually assembled de novo to produce long stretches of sequences called contigs. Taxonomic identification of the resulting contigs is performed by matching them to the genomes and sequences in nucleotide or protein databases; for this, various versions of BLAST are most commonly used. Advanced characterization of bacterial organisms can be also performed, allowing to obtain the necessary depth and breadth of coverage for genetic characterization results. Gene calling can be performed in a variety of ways, including RAST or using NCBI services at the time of full genome submission. Results of multiple annotation tools can be compared for accuracy and completeness and, if necessary, merged using BEACON. For characterization of antibiotic resistance genes, the Resistance Gene Identifier from the Comprehensive Antibiotic Resistance Database (CARD) is commonly used. To characterize virulence factor genes, ShortBRED offers analyses with a customized database from the Virulence Factor Database.
Applications in Infectious diseases
One way to detect these pathogens is detect part of their genome by metagenomics sequencing (Next Generation Sequencing-mNGS), which can be targeted or untargeted.
Targeted
Because of that, the sensitivity to detect microorganisms that are being targeted usually increases, but this comes with a limitation of the amount of identifiable pathogens.
Untargeted
The untargeted analysis is a metagenomic Shotgun sequencing approach. The whole DNA and/or RNA is sequenced with this approach using universal primers. The resultant mNGS reads can be assembled into partial or complete genomes. These genome sequences allow to monitor hospital outbreaks to facilitate infection control and public health surveillance. Also, they can be used for subtyping (identificate a specific genetic variant of a microorganism).
Untargeted mNGS is the most promising approach to analyse clinical samples and provide a comprehensive diagnosis of infections. Various groups have validated mNGS in Clinical Laboratory Improvement Amendments (CLIA), such as meningitis or encephalitis, sepsis and pneumonia. This method can be very helpful in the settings where no exact infectious etiology is suspected. For example, in patients with suspected pneumonia, identification of the underlying infectious etiology as in COVID-19 has important clinical and public health implications.
The traditional method consists on formulating a differential diagnosis on the basis of the patient's history, a clinical presentation, imaging findings and laboratory testing. But here it is suggested a different way of diagnosis; metagenomic next-generation sequencing (NGS) is a promising method because a comprehensive spectrum of a potential causes (viral, bacterial; fungus and parasitic) can be identify by a single assay.
Below are some examples of the metagenomic sequencing application in infectious diseases diagnosis.
Examples
Diagnosis of meningitis and encephalitis
The traditional method used to the diagnosis of infectious diseases has been challenged in some cases: neuroinflammatory diseases, lack of diagnostic tests for rare pathogens and the limited availability and volume of the Central Nervous System (CNS) samples, because of the requirement for invasive procedures. Owing to these problems, some assays suggest a different way of diagnosis, which is the metagenomic next-generation sequencing (NGS). Summarising, NGS can identify a broad range of pathogens in a single test.
Some studies evaluate the clinical usefulness of metagenomic NGS for diagnosis neurologic infections, in parallel with conventional microbiologic testing. It has been seen that the highest diagnostic yield resulted from a combination of metagenomics NGS of CSF and conventional testing, including serologic testing and testing of sample types other than CSF. Sometimes neurologic infections remain undiagnosed in a proportion of patients despite conventional testing.
The results of metagenomic NGS can also be valuable even when concordant with results of conventional testing, not only providing reassurance that the conventionally obtained diagnosis is correct but also potentially detecting or ruling out coinfections, specially in immunocompromised patients.
Study of antimicrobial resistance
Nowadays to detect resistances of different microbes is used a technique called Antibiotic Sensitivity (AST), but several studies have discovered that bacterial resistance is in the genoma and it is transferred by horizontal way (HGT), so sequencing methods are being developed to ease the identification and characterization of those genomes and metagenomes. For the moment exist the following methods to detect antimicrobial resistances:
Antibiotic sensitivity: an advantage about this method is that it gives information for patients treatment. There are also some disadvantages, one of them is that this technique is only useful in cultivable bacteria for which competent personal is required.
Sequencing methods: some advantages of those methods over the AST technique are that it is rapid and sensible, it is useful on both bacteria that grow on artificial media and those that do not, and it permits compare studies in several organisms. One type of sequencing method can be used in preference to another depending on the type of the sample, for a genomic sample assembly-based methods is used; for a metagenomic sample it is preferable to use read-based methods.
Metagenomic sequencing methods have provided better results than genomics, due to these present fewer false negatives. Within metagenomics sequencing, functional metagenomic is a powerful approach for characterizing resistomes; a metagenomic library is generated by cloning the total community DNA extracted from a sample into an expression vector, this library is assayed for antimicrobial resistance by plating on selective media that are lethal to the wild-type host. The selected inserts from the surviving recombinant, antimicrobial-resistant host cells are then sequenced, and resulting sequences are subsequently assembled and annotated (PARFuMS).
Functional metagenomics has enabled the discovery of several new antimicrobial resistance mechanisms and their related genes, one such example is the recently discovered tetracycline resistance mechanism by tetracycline destructases. It is important to incorporate not only the antimicrobial resistance gene sequence and mechanism but also the genomic context, host bacterial species and geographic location (metagenome).
Pandemic preparedness
Potentially dangerous pathogens such as ebolaviruses, coronaviruses etc., and the closest genetic relative for unknown pathogens, could be identified immediately, prompting further follow-up. Its role in the future of pandemic preparedness is anticipated and could exist as the earliest surveillance system we may have to detect outbreaks of unknown etiology and to respond in an opportune manner.
Clinical microbiome analyses
The use of mNGS to characterize the microbiome has made possible the development of bacterial probiotics to be administrated as pills, for example, as a treatment of Clostridioides difficile-associated diseases.
Human host response analyses
The studying of genes expression allows to characterize a lot of infections, for example infections due to Staphylococcus aureus, Lyme disease, candidiasis, tuberculosis and influenza. Also, this approach can be used for cancer classification.
RNAseq analysis have a lot of other purposes and applications such as to identify novel or under appreciated host–microbial interactions directly from clinical samples, to make indirect diagnosis on the basis of a pathogen specific human host response and to discriminate infectious versus noninfectious causes of acute illness.
Challenges
Clinical utility
Most of the metagenomics outcomes data generated consist of case reports which belie the increasing interest on diagnostic metagenomics.
Accordingly, there is an overall lack of penetration of this approach into the clinical microbiology laboratory, as making a diagnosis with metagenomics is still basically only useful in the context of case report but not for a true daily diagnostic purpose.
As of 2018, cost-effectiveness modelling of metagenomics in the diagnosis of fever of unknown origin concluded that, even after limiting the cost of diagnostic metagenomics to $100 – 1000 per test, it would require 2.5-4 times the diagnostic yield of computed tomography of the abdomen and pelvis in order to be cost neutral and cautioned against ‘widespread rush’ to deploy metagenomic testing.
Furthermore, in the case of the discovery of potential novel infectious agents, usually only the positive results are published even though the vast majority of sequenced cases are negative, thus resulting in very biased information. Besides, most of the discovery work based in metagenomic that precedes the diagnostic-based work even mentioned the known agents detected while screening unsolved cases for completely novel causes.
Laboratory validity
To date, most published testing has been run in an unvalidated, unreportable manner. The ‘standard microbiological testing’ that samples are subjected to prior to metagenomics is variable and has not included reverse transcription-polymerase chain reaction (RT-PCR) testing for common respiratory viruses or, routinely 16S/ITS PCR testing.
Given the relative costs of validating and performing metagenomic versus 16S/ITS PCR testing, the second one is considered an easier and more efficient option. A potential exception to the 16S/ITS testing is blood, given the huge amount of 16S sequence available, making clean cutoffs for diagnostic purposes problematic.
Furthermore, almost all of the organisms detected by metagenomics for which there is an associated treatment and thus would be truly actionable are also detectable by 16S/ITS testing (or 16S/ITS-NGS). This makes questionable the utility of metagenomics in many diagnostic cases.
One of the main points to accomplish laboratory validity is the presence of reference standards and controls when performing mNGS assays. They are needed to ensure the quality and stability of this technique over time.
Sense and sensitivity
In clinical microbiology labs, the quantitation of microbial burden is considered a routine function as it is associated with the severity and progression of the disease. To achieve a good quantitation a high sensitivity of the technique is needed.
Whereas interfering substances represent a common problem to clinical chemistry or to PCR diagnostics, the degree of interference from host (for example, in tissue biopsies) or nonpathogen nucleic acids (for example, in stool) in metagenomics is a new twist. In addition, due to the relative size of the human genome in comparison with microbial genomes the interference can occur at low levels of contaminating material.
Another challenge for clinical metagenomics in regards to sensitivity is the diagnosis of coinfections where there are present high-titer pathogens that can generate biased results as they may disproportionately soak up reads and make difficult to distinguish the less predominant pathogens.
In addition to issues with interfering substances, specially in the diagnosis area, accurate quantitation and sensitivities are essential as a confusion in the results can affect to a third person, the patient. For these reason, practitioners currently have to be keenly aware of the index-swapping issues associated with Illumina sequencing which can lead to trace incorrectly barcoded samples.
Since metagenomics has typically been used on patients for whom every other test to date has been negative, questions surrounding analytical sensitivity haven been less germane. But, for ruling out infections causes being one of the more important roles for clinical metagenomics it is essential to be capable to perform a deep enough sequencing to achieve adequate sensitivities. One way could be developing novel library preparation techniques.
Cost considerations
As of 2018, the Illumina monopoly on high-quality next-generation sequencing reagents has meant that the sequencing reagents alone cost more than FDA-approved syndromic testing panels. Also additional direct costs of metagenomics such as extraction, library preparation, and computational analysis have to be considered. In general, metagenomic sequencing is most useful and cost efficient for pathogen discovery when at least one of the following criteria are met:
the identification of the organism is not sufficient (one desires to go beyond discovery to produce data for genomic characterization),
a coinfection is suspected,
other simpler assays are ineffective or will take an inordinate amount of time,
screening of environmental samples for previously undescribed or divergent pathogens.
See also
Sequencing
Clinical data management
Nanopore sequencing
References
External links
Clinical Laboratory Improvement Amendments CDC
Improved annotation of antibiotic resistance determinants reveals microbial resistomes cluster by ecology Article on functional metagenomic selections for resistance
Genomics
Metagenomics
Pathogen genomics | Clinical metagenomic sequencing | [
"Biology"
] | 3,941 | [
"Molecular genetics",
"DNA sequencing",
"Pathogen genomics"
] |
62,084,982 | https://en.wikipedia.org/wiki/Xerez%20Cromlech | The Xerez Cromlech (), also known as the Xarez Cromlech, is a megalithic complex that is believed to date back to the 4th or 5th millennia BCE. It is situated near the town of Monsaraz in the Évora district of the Alentejo region of Portugal, close to the Spanish border. The present site of the cromlech is not its original location. Due to the construction of the Alqueva Dam for hydroelectric purposes, which led to the flooding of the original site from 2002, it was transferred from an area that is now under water to its present site close to the Orada Convent. This was the only monument to be moved, with the dam leading to the disappearance of prehistoric engravings and the Roman Castelo da Lousa.
Layout
Although it has much in common with megalithic stone circles, the Xerez cromlech is, in fact, square. There has been some dispute about the authenticity of the square layout or even whether it is a cromlech at all. When first discovered, the stones had been widely dispersed due to agricultural work and an initial topographical survey only identified 12 stones that could be part of a cromlech, although the present layout has 55. As the original site is now under water it is unlikely that the dispute will ever be resolved. It is acknowledged that the square shape results solely from interpretations by José Pires Gonçalves, a doctor and an amateur archaeologist from Reguengos de Monsaraz, previously responsible for identifying the nearby Menhir of Outeiro, who identified the stones as a cromlech in 1969, having been alerted to the existence of the central phallic stone by two local residents, José Cruz e Leonel Franco.
Menhirs
The 55 menhirs are of different types of granite of local origin. These are mainly between 0.37 and 2.10 meters in height, with varying shapes (ovoid, slightly flattened, cylindrical, sub-square, conical or polyhedral). Originally raised and put into position by Gonçalves and others in 1972, they are arranged around a large phallic menhir, which is about 4.50 meters high and weighs 7 tons. Seven menhirs, including the central one, are decorated with different motifs that show strong similarities to the designs identified in other monuments of the same type in the region, such as the better-known Almendres Cromlech.
1998 excavation
In 1998, as part of the efforts to minimize the impact on Portugal’s heritage resulting from the construction of the dam, Mário Varela Gomes of the New University of Lisbon (Universidade NOVA de Lisboa) excavated the site, identifying a diverse set of highly fragmented items, including lithic artefacts (trapezoids and flakes in silica, silicon shale, quartz and quartzite), and some fragments of ceramic containers, such as decorated cups. At the time, Gomes apparently saw no reason to contradict the findings of Gonçalves. The architectural complexity of the site, the decorations on some of the menhirs and the archaeological materials collected suggested use of the area in the Late Paleolithic, a first phase of construction of the site in the early and middle Neolithic, and redesign in the late Neolithic (including placement of the central menhir). The complex is believed to have been used throughout the Chalcolithic.
Transportation
In November 2001, three months after the dam's floodgates were closed, the whole complex was dismantled and the stones were stored for more than two years. The present location was chosen because of the availability of government land and the fact that there would also be room to build a planned archaeology museum, which remained unbuilt in 2023. The reconstruction of the cromlech was carried out on 24-25 June 2004 to coincide with the summer solstice.
References
External links
Video of the Cromlech
Buildings and structures completed in the 5th millennium BC
Buildings and structures completed in the 4th millennium BC
1969 archaeological discoveries
National monuments in Évora District
Megalithic monuments in Portugal
Prehistoric sites in Portugal
Buildings and structures in Reguengos de Monsaraz
Stone Age Europe
Prehistoric art
Tourist attractions in Évora District
Summer solstice | Xerez Cromlech | [
"Astronomy"
] | 872 | [
"Time in astronomy",
"Summer solstice"
] |
62,085,025 | https://en.wikipedia.org/wiki/Cyanophosphaethyne | Cyanophosphaethyne is an unstable molecular compound with structural formula N≡C–C≡P. It can be considered as cyanogen with one nitrogen atom replaced by phosphorus. It has been made as a dilute gas. Cyanophosphaethyne has been tentatively detected in the interstellar medium. Other structural isomers, such as C≡N–C≡P (isocyanophosphapropyne), C≡C-N≡P (azaphosphadicarbon), and N≡C–P=C (isocyanophosphavinylidene), have not been observed. The molecule has linear molecular geometry (C∞v molecular symmetry).
Production
Cyanophosphaethyne can be produced by heating cyanogen azide and phosphaethyne gases to 700 °C:
N≡C–N3 + H–C≡P → N≡C–C≡P + HN3
Another method is to heat anhydrous methyl cyanide with anhydrous phosphorus trichloride:
N≡C–CH3 + PCl3 → N≡C–C≡P + 3HCl
Properties
The dipole moment is 3.5 Debye. Having a large dipole makes the molecule easier to detect by certain types of spectroscopy than many other phosphorus containing molecules. The bond lengths are C≡N = 1.159 Å, C–C = 1.378 Å, and C≡P = 1.544 Å.
References
Organophosphanes
Nitriles | Cyanophosphaethyne | [
"Chemistry"
] | 329 | [
"Nitriles",
"Functional groups"
] |
62,086,463 | https://en.wikipedia.org/wiki/Metal%E2%80%93inorganic%20framework | Metal–inorganic frameworks (MIFs) are a class of compounds consisting of metal ions or clusters coordinated to inorganic ligands to form one-, two-, or three-dimensional structures. They are a subclass of coordination polymers, with the special feature that they are often porous. They are inorganic counterpart of Metal–organic frameworks.
History
Millon's base which have been known since early 20th century, can be considered as MIFs.
Linkers
MIF with Borazocine linker was developed for hydrogen storage. Cu2I2Se6 has Se6 linkers. There are many MIFs with pnictogen linkers.
References
Crystal engineering
Porous media
Coordination polymers
Inorganic compounds | Metal–inorganic framework | [
"Chemistry",
"Materials_science",
"Engineering"
] | 146 | [
"Porous media",
"Materials science stubs",
"Inorganic compounds",
"Materials science"
] |
62,086,726 | https://en.wikipedia.org/wiki/George%20Douglas%20of%20Parkhead | George Douglas of Parkhead, (died 1602), was a Scottish landowner, mining entrepreneur, Provost of Edinburgh, and Keeper of Edinburgh Castle.
Career
George Douglas was a son of George Douglas of Pittendreich, the name of his mother is unknown. His half-sister, Elizabeth, daughter of Lady Dundas, married Smeton Richeson. He married Marioun Douglas, heiress of Parkhead or Parkheid, and so became known as George Douglas of Parkhead. Parkhead is close to the Lanarkshire town of Douglas. He was later Provost of Edinburgh.
Refortification of Edinburgh Castle
After Edinburgh Castle was recovered from William Kirkcaldy of Grange in May 1573, George Douglas was appointed its Captain or keeper by his half-brother Regent Morton. George Douglas supervised the rebuilding of part of the back wall and other repairs, buying lime, sand, slate and glass. Part of the running expenses, or "sustenation" of the castle was paid to Douglas from the customs of Edinburgh town by Robert Gourlay.
Parkhead is credited with building the half-moon battery at Edinburgh castle, the Historie of King James the Sext records that Regent Morton appointed him captain, and caused "masonis to begin to redd (clear away) the bruisit wallis, and to repaire the foirwark to the forme of ane bulwark, platt and braid above, for the resett and ryving (receiving) of many canonis." Some building accounts from this work survive.
Douglas and Regent Morton
Douglas prospered during the regency of his brother, James Douglas, 4th Earl of Morton, and his servant Florence Douglas was made Rothesay Herald. When his brother resigned the regency of Scotland in March 1579, George Douglas of Parkhead made an inventory of the personal jewellery of Mary, Queen of Scots kept in Edinburgh Castle, and of the textiles, the royal tapestries, Mary's remaining costume, her pictures, dolls, and library, and he itemised the artillery of the castle and the tools in its workshops. The taking of this inventory was described in the chronicle attributed to David Moysie.
Douglas was involved in lead mining at Wanlockhead and Glengonnar or Leadhills in Lanarkshire and in Orkney. In June 1581 his interest in the lead mines with all the lead ore recovered was confiscated and given to James Stewart, Earl of Arran because he had withheld Torthorwald Castle from the earl.
Parkhead wrote to Francis Walsingham in June 1582 to thank him for hospitality in England, mentioning his friend John Selby of the garrison of Berwick-upon-Tweed. He had written to Selby in May 1582 describing a rumour that James VI would be sent to France.
In August 1584 George Douglas and his sons James and George were declared traitors and their goods and lands forfeited for their role "art and part" in the Raid of Stirling in April 1584.
Norway
James VI of Scotland sailed to Norway to meet his bride Anna of Denmark in October 1589. George Douglas of Parkhead was one of his companions. He wrote from Oslo to the Earl of Morton on 30 November 1589. The king had decided to stay over winter at the Danish court, and the Earl's son Archibald Douglas had decided to go travelling. He had asked Parkhead to go with him.
Later life
After their kinsman William Douglas, 6th Earl of Morton had been imprisoned in their keeping at Edinburgh Castle, Marion Douglas wrote to his wife Agnes Leslie, Countess of Morton to thank her for a gift of cheese from her farms at Fossoway near Lochleven Castle. She said that Morton had "received but very simple entertainment here".
Another of Marion Douglas's letters concerns the lead mines. On 6 August 1592 she wrote from Parkhead to Lord Menmuir asking for his decision about the mining concessions between Eustachius Roche and her husband. She had been obliged to order her miners to suspend working, putting them to other work or laying them off.
On 20 December 1593 George Douglas and his son James made over some of their lead mining rights in Glengonnar to the goldsmith and financier Thomas Foulis.
An English prospector Stephen Atkinson writing in 1619 stated that "George Parkhead" was killed by a landslide in wet weather at a mine working at "Short-clough brayes". It took three days to dig him out. The Shortcleuch water joins the Elvan and falls into the Clyde. Some sources suggest the victim of this accident was a son of George Douglas of Parkhead, and it occurred in 1586 while he was prospecting for gold.
George Douglas of Parkhead's will was registered in Edinburgh in 1602. It mentions oats stored in the barn yard of "Auld Foulden".
Family
The children of George Douglas and Marion Douglas included;
James Douglas of Parkhead (d. 1608), who married Elizabeth Carlyle, daughter of William, Master of Carlyle. She was an heiress and the marriage was probably arranged by Regent Morton. It was said that he was cruel to her. On 2 November 1596 James Douglas of Parkhead and his accomplices killed his father's enemy, James Stewart, former Earl of Arran at Symington. They claimed that Stewart was technically a rebel, "at the horn". As his tombstone at Holyrood Abbey mentions, James Douglas was killed on the Royal Mile Edinburgh on 14 July 1608, by Captain William Stewart, son of William Stewart of Monkton and a nephew of Arran. Elizabeth Carlyle then married William Sinclair of Blaas.
The children of James Douglas and Elizabeth Carlyle included; James Douglas, who married (1) Elizabeth Gordon of Lochinvar, (2) Anne Saltonstall, daughter of Richard Saltonstall, Lord Mayor of London.
George Douglas of Mordington, who married Margaret Dundas, daughter of Archibald Dundas of Fingask, and sister of William Dundas who wrote letters commenting on the court of Anne of Denmark in 1590 and painted ceilings in 1593. She was the widow of William Kerr of Ancram, and mother of the courtier Robert Kerr.
The children of George Douglas and Margaret Dundas included; George Douglas ambassador to Poland and Sweden for Charles I of England; and Margaret Douglas who married Sir James Lockhart of Lee, her children included William Lockhart who was ambassador to France for Oliver Cromwell; George Lockhart a lawyer; and Anne Lockhart who married George Lockhart of Tarbrax.
John Douglas, minister of Crail.
Catherine Douglas, who married Sir James Dundas of Arniston, governor of Berwick upon Tweed after 1603.
Margaret Douglas, who married (1) Edward Sinclair of Roslynn and Herbertshire, (2) Sir Patrick Home of Ayton.
Martha Douglas, who married Robert Bruce, minister of Edinburgh. Their betrothal ring was kept by the Bruce family of Kinnaird, Stirlingshire.
Mary Douglas, who married John Carruthers of Holmains in Annandale.
References
External links
Two Letters about Cheese: Marion Douglas, Lady Parkhead
Scheduled Monument: Gold scours, cut into the hillside above the Shortcleuch Water, SM13677, Historic Environment Scotland
History of Leadhills, Leadhills Estate.
Robert William Cochran-Patrick, Early Records Relating to Mining in Scotland (Edinburgh, 1878)
16th-century Scottish people
16th-century births
Year of birth unknown
1602 deaths
Lord provosts of Edinburgh
Mining engineers
Scottish mining engineers
Gold mines in Scotland
16th-century Scottish businesspeople
Lairds | George Douglas of Parkhead | [
"Engineering"
] | 1,570 | [
"Mining engineering",
"Mining engineers"
] |
62,086,780 | https://en.wikipedia.org/wiki/Wireless%20Emergency%20Alerts%20in%20Germany | There are various Wireless Emergency Alerts in Germany which inform citizens about important incidents, disasters and dangerous situations, as well as severe weather. Since February 2023, the alerts of the four main systems have been shared and disseminated in parallel.
Background
Since WWII, the traditional method for informing the public about a disaster in Germany has been civil defence sirens. An equivalent to the US Emergency Broadcasting System for sending messages via radio and TV did not exist in Germany for a long time but such a system is now part of the Modular Warning System (MoWas). MoWas is developed by the Federal Office for Civil Protection and Disaster Relief (BBK) to warn the population and is coupled to authorities, media and all situation centres of the state governments and their redundancy locations as well as in all integrated control centres in North Rhine-Westphalia, Brandenburg and Schleswig-Holstein. The system is connected to all public broadcasters, a number of private broadcasters, the news agencies dpa, AFP, dts Nachrichtenagentur, the digital billboards of Ströer Media and Wall GmbH, T-Online International, the situation room of Deutsche Bahn and all relevant alert apps.
Cell Broadcast
There were increasing calls to use the Cell Broadcast service in Germany to warn the population in the event of a disaster. The demands intensified after the Floods in Western and Central Europe in 2021.
In August 2021, the German federal government announced that it would introduce Cell Broadcast within the next year. The Bundestag and Bundesrat subsequently approved the necessary amendment to the Telecommunications Act. The Bundesrat approved the introduction of the mobile warning regulation of the Federal Ministry for Economic Affairs and Climate Action on November 26, 2021. On the second nationwide warning day on December 8, 2022, cell broadcast was successfully used in Germany for the first time. The message was intended to reach all mobile devices that are compatible with Cell Broadcast and have reception.
In February 2023, the Cell Broadcast warning system officially started regular operation. In June 2023, mobile phone operator Vodafone Germany announced that since the start of official operation, 77 warning messages had been sent via Cell Broadcast in various parts of Germany.
NINA
In 2015, the Federal Office for Civil Protection and Disaster Relief (Bundesamt für Bevölkerungsschutz und Katastrophenhilfe) at BMI presented an emergency information and news app called NINA. Since 2019, the KATWARN system and the Federal MoWaS system have been coupled: warnings of KATWARN and the NINA app are displayed on both sides.
EU-Alert
EU-Alert is the wireless emergency system of the European Union and officially called European Public Warning Service. EU-Alert is compatible with the Wireless Emergency Alerts (WEA) standard as used in the United States and based on Cell Broadcast. Since 2012, mobile operating systems have supported EU-Alert/WEA/CMAS via Cell Broadcast for public warning messages by default.
Katwarn
Katwarn was the first alert system in Germany based mainly on smartphone apps and was introduced in 2009. The service is provided by the private company Combirisk GmbH. Fraunhofer Institute FOKUS developed Katwarn on behalf of the major insurance companies in Germany.
Katwarn (also known as KATWARN) is an alert and information system that informs the affected citizen in disasters and dangerous situations (e.g. large fires, power outages, bomb finds). Since 2011, Katwarn has been in use in Germany in various cities, counties and city states, as well as at the state (Bundesländer) and federal level. It can be used, for example, via a smartphone app. Registration to the system is free and it currently serves around 2.5 million users. The app is available worldwide in the app stores for iPhone, Android and Windows Phone.
Since July 2017, Katwarn has also been available in Austria.
BIWAPP
The warning app BIWAPP is used by some cities and counties for regional and local urgent reports. The app also displays the disaster warnings of the BBK and the severe weather warnings of the German Weather Service (DWD). All notifications and disaster alerts are sent directly from the officially responsible institutions such as civil protection authorities, municipalities and cities as well as their control centres.
WarnWetter
German Weather Service, DWD invented in 2015 a weather warning app, called WarnWetter. At the end of 2017, it was used by 4.9 million users. In 2017, a private weather forecast company brought suit against DWD, because of its free app in 2017. After judgment by the district court of Bonn, there is a free app with commercials and another version for which users have to pay.
References
Emergency Alert System
Emergency population warning systems
Emergency management in Europe
Emergency management in Germany | Wireless Emergency Alerts in Germany | [
"Technology"
] | 982 | [
"Warning systems",
"Emergency population warning systems"
] |
62,087,507 | https://en.wikipedia.org/wiki/Oil%20and%20Gas%20Climate%20Initiative | The Oil and Gas Climate Initiative (OGCI), is an international industry-led organization which includes 12 member companies from the oil and gas industry: BP, Chevron, CNPC, Eni, Equinor, ExxonMobil, Occidental, Petrobras, Repsol, Saudi Aramco, Shell and TotalEnergies represent over "30% of global operated oil and gas production." It was established in 2014 and has a mandate to work together to "accelerate the reduction of greenhouse gas emissions" in full support of the Paris Agreement and its aims."
Their mandate says that they will "seek actions" to "accelerate and participate in the energy transition." On November 4, 2016 OGCI announced the creation of the OGCI Climate Investments fund which will invest $1 billion over 10 years in companies or projects that reduce "methane emissions from gas production", on projects or "technologies to capture and either use or store carbon emissions", as well as on energy efficiency.
The fund invests in reducing the carbon footprint of the oil and gas industry and other emitting sectors, rather than in renewable energy. Former BP CEO Bob Dudley is the chair of the OGCI CEO steering committee and Bjørn Otto Sverdrup is the chair of the OGCI executive committee. Pratima Rangarajan is the CEO of OGCI Climate Investments.
Background
The industry-led Oil and Gas Climate Initiative (OGCI) was created in 2014 by CEOs of the world's largest energy companies to "seek action" to support the Paris Agreement. The member companies which include BP, Chevron, CNPC, Eni, Equinor, ExxonMobil, Occidental, Pemex, Petrobras, Repsol, Saudi Aramco, Shell and Total, represent over "32% of global operated oil and gas production."
As part of their initiative to "improve their environmental reputation" the OGCI announced at an event held in London, that they would be investing $1bn over the next decade in "innovative low emissions technologies". The announcement, which was planned to "coincide" with the Paris agreement which came into effect on the same day. The Telegraph had predicted that the OGCI could face "fierce scrutiny and accusations of "greenwashing" for the announcement which some environmentalists saying that "the 'big oil' business model is fundamentally incompatible with avoiding dangerous climate change." The Telegraph said that OGCI chair and BP CEO Bob Dudley makes more than 1 billion a year.
On September 22, 2019, the OGCI hosted an "invitation-only forum" on the "sidelines" of the September 23, climate action summit organized by the UN secretary general, António Guterres, which was held in New York. The day before the UN "climate action summit"—which included "[W]orld leaders, academics, government representatives and environmentalists" came together for The UN "climate action summit"—OGCI oil and gas executives held their own "closed high-level discussion" with key stakeholders. According to The Guardian, critics said that the OGCI was "attempt[ing] to influence negotiations in favour of fossil fuel companies."
On September 23, the OGCI held their formal forum at the Morgan Library and Museum, New York.
Targets
In 2017, OGCI members developed a baseline of "aggregated upstream oil and gas operations emissions" of 24 kg CO2e/boe.
Methane intensity
In 2018, OGCI set a methane intensity target. In 2018, member companies had "reduced collective methane intensity by 9%" and was "on track to meet the 2025 target of below 0.25%."
Carbon intensity
At their September 2019 forum, OGCI said that they were "working on a carbon intensity target to reduce by 2025 the collective average carbon intensity of member companies' aggregated upstream oil and gas operations." Among the actions to meet their targets of reducing carbon intensity, the OGCI listed "improving energy efficiency, minimizing flaring, upgrading facilities and co-generating electricity and useful heat."
Carbon pricing
Member companies pledged to "support policies that attribute an explicit or implicit value to carbon" as "one of the most cost-efficient ways to achieve the low carbon transition as early as possible" at their September 2019 forum.
Reduce flaring
By October 2019, the fossil-fuel executives said that until recently they had been making progress in cutting back on routine flaring, where vast amounts of natural gas are burned off as a waste "by-product" during the extraction of crude oil. Oil extraction companies focus on drilling and pumping oil which is highly lucrative, but the less-valuable gas accompanying the oil is more difficult to transport to consumers. Production growth has "far outpaced pipeline construction" during the boom in the Permian and Bakken oil fields.
Both gas flaring and gas venting waste a primary energy resource and release potent greenhouse gases into the atmosphere. Regulation of the amount of each type of waste varies from one jurisdiction to another. Instances also occur where companies have access to transport capacity, but are allowed to flare rather than pay pipeline costs.
As part of its flaring efforts, OGCI is also a member of Methane Guiding Principles, an industry consortium that aims to reduce methane emissions—including from flaring—from the energy supply chain.
Investments
The OGCI Climate Investments fund will not invest in renewables. It will focus on action that will reduce "methane emissions from gas production" and on "technologies to capture and either use or store carbon emissions. At their New York September 2019 forum, OGCI said that they had " 15 investments in its portfolio," which includes Kelvin, SeekOps, Boston Metal, 75F, Norsepower, and XL. OGCI Climate Investments focus on "innovative companies that are ready to be commercialized" in collaboration with "global co-investors and industrials to achieve speed and scale."
Wabash Valley Resources
On May 20, 2019 OGCI announced their funding support of the Terre Haute, Indiana-based Wabash Valley Resources that will "capture and sequester 1.5-1.75 million tons of CO2 annually from Wabash Valley Resources co-located ammonia plant" making it "the largest carbon sequestration project in the United States".
SeekOps
In September 2019, OGCI Climate Investments and Equinor Technology Ventures provided funding for SeekOps, which is a "technology spinoff NASA's Jet Propulsion Laboratory". SeekOps uses "integrated drone-based systems" capable of detect[ing], localiz[ing], and "quanify[ing] natural gas emissions.
Initiatives
In September 2019, OGCI announced a KickStarter campaign to increase the "carbon capture, use and storage (CCUS)" globally to "achieve net zero emissions."
External links
https://ogci.com
References
Petroleum industry | Oil and Gas Climate Initiative | [
"Chemistry"
] | 1,415 | [
"Petroleum industry",
"Petroleum",
"Chemical process engineering"
] |
62,088,287 | https://en.wikipedia.org/wiki/WD%200145%2B234 | WD 0145+234 is a white dwarf star approximately from Earth in the constellation of Aries that has been associated with studies suggesting that a very large exoasteroid near the star was substantially disrupted, resulting in a considerable amount of dust and debris around the star. Alternatively, the outburst around WD 0145+234 is explained with ongoing collisions between planetesimals inside the dusty debris disk around the white dwarf.
The outburst around WD 0145+234 appeared in 2018 in data by the Wide-Field Infrared Survey Explorer. Outburst around white dwarfs in the infrared are not unusual. Novae and dwarf novae also show outbursts, but they are accompanied by an outburst in the optical and appear around binaries. WD 0145+234 is however a single white dwarf and did not show any brightening in the optical images taken by CRTS and ASASSN. This suggested that the outburst was caused by recent replenishing or redistribution of dust. A follow-up study using the Spitzer Space Telescope found a decrease of the infrared brightness, beginning in late 2019. The decrease is accompanied by small bumps superimposed on the decrease of infrared brightness. The team studying WD 0145+234 with Spitzer concluded that the increase of brightness was not caused by the a tidal disruption of an exoasteroids, but by ongoing collisions in the disk around the white dwarf. A similar decrease in infrared brightness was found around the white dwarf GD 56. WD 0145+234 is also unusual because not only does it show metal pollution in the form of absorption lines, which are found around 25-50% of white dwarfs, but also emission lines caused by calcium gas, which are less common. It is still not clear what causes the metal emission lines around some white dwarfs, but the existence of such lines around WD 0145+234 suggests that metal gas is formed in collisions. There are still some unanswered questions for this hypothesis: Some white dwarfs with metal gas show variable emission lines, while WD 0145+234 does not show any variability in the calcium emission line. It is unclear why some white dwarfs show variable metal emission lines.
Other white dwarfs with planetary pollution also show infrared variability, with the prototype being G29-38, which showed a decrease of infrared flux by about 35% over a period of 300 days. White dwarfs with the highest infrared variations show calcium emission lines, just like WD 0145+234. WD 0145+234 might be the system with one of the highest activity of this class of objects.
Observations with NIRSpec released in a preprint in October 2023 showed that the debris disk is returning to its quiescent state. MIRI spectroscopy showed emission at 9-12 micron, consistent with silicate minerals and a tentative emission feature around 7 microns was interpreted as carbonates. The authors noted that emission of silicate minerals begins at 9 microns and therefore resembles more the emission feature of enstatite than that of fosterite.
See also
Disrupted planet
List of stars that have unusual dimming periods
List of exoplanets and planetary debris around white dwarfs
Tabby's Star
WD 1145+017
References
Aries (constellation)
White dwarfs | WD 0145+234 | [
"Astronomy"
] | 664 | [
"Aries (constellation)",
"Constellations"
] |
62,088,340 | https://en.wikipedia.org/wiki/Exoasteroid | An exoasteroid, exo-asteroid or extrasolar asteroid is an asteroid located outside the Solar System.
Evidence
Scientists propose that the formation of exoasteroids often results from the fragmentation of exoplanets by gas giants. These exoasteroids are presumed to be the remnants of smaller celestial bodies that endured the demise of their parent exoplanet. Similar processes are hypothesized to have occurred during the formation of our Solar System.
NASA has conducted studies confirming that the presence of asteroid belts around stars is a common phenomenon in nearly any solar system hosting planets comparable in size to the outer and inner planets of our Solar System.
History
In December 1988, American astrophysicists Benjamin Zuckerman and Eric Becklin detected a substantial circumstellar disc encircling the white dwarf star G 29-38, stemming from a near-infrared survey of 200 white dwarfs. Zuckerman and Becklin conducted further investigations on the white dwarf star, uncovering that the circumstellar disc emits notable radiation within the 2 to 5 micrometer range. This discovery suggests potential interactions between exoasteroids and radiant matter, possibly leading to their ejection into space. Subsequent observations in 2004 by the Spitzer Space Telescope revealed the presence of a dust cloud surrounding G 29-38. This phenomenon is believed to have originated from the disintegration of an exocomet or exoasteroid as it interacted with the white dwarf.
In May 2023, the James Webb Space Telescope provided images of Fomalhaut, a young star positioned 25 light-years (ly) away from Earth. Scientists analyzed these images and conducted simulations and tests on Fomalhaut's asteroid belt, proposing that it likely formed due to collisions involving larger celestial bodies.
Another notable star hosting an asteroid belt is the white dwarf star WD 0145+234. It is hypothesized that WD 0145+234 once hosted an exoasteroid or exoplanet in orbit around it, which was disrupted, leading to the formation of a substantial exoasteroid belt. Due to the star's dimensions, scientists infer that the accretion disk surrounding WD 0145+234 is highly active, resulting in the regular disruption of exoasteroids by the star's gravitational pull. In 2018, astronomers observed a 10% increase in the star's mid-infrared light, indicative of the recent destruction of an exoasteroid, which led to the formation of a cloud of metallic dust partially obscuring WD 0145+234 from Earth's view.
Detection
In 2013, astronomers discovered fragmented remnants of an exoasteroid orbiting the star GD 61. Scientists determined that the asteroid possessed a surface rich in water, comprising approximately 26% water by mass, a composition akin to the surface water, primarily in the form of ice, found on the dwarf planet Ceres. It suggests the potential existence of an exoplanet with liquid water around the star at some point in its history. It is proposed that the asteroid met its demise due to interactions with its star, leading to its fragmentation and subsequent formation of an asteroid belt around the star.
Following this discovery, scientists used the Cosmic Origins Spectrograph aboard the Hubble Space Telescope to analyze the chemical composition of the asteroid; it showed the presence of magnesium, silicon, iron, and oxygen within the asteroid's water.
Proposed observational methods
Exoasteroids can be detected through various methodical processes. The transit method is a common technique used to discover extrasolar objects as they pass in front of their host star, providing scientists with the opportunity to observe their shape. Spectroscopy can be used to identify distinctive characteristics of exoasteroids, and allows to detect surface features. Other techniques include remote sensing and data from past missions to minor planets.
See also
Accretion disk
Circumstellar disc
Debris disk
Disrupted planet
List of asteroid close approaches to Earth
List of exceptional asteroids
Lost minor planet
Meanings of minor-planet names
Protoplanetary disk
References
External links
NASA Asteroid and Comet Watch site
Minor planets
Exoplanetology
Solar System | Exoasteroid | [
"Astronomy"
] | 850 | [
"Outer space",
"Solar System"
] |
62,089,600 | https://en.wikipedia.org/wiki/CCIR%20476 | CCIR 476 is a character encoding used in radio data protocols such as SITOR, AMTOR and Navtex. It is a recasting of the ITA2 character encoding, known as Baudot code, from a five-bit code to a seven-bit code. In each character, exactly four of the seven bits are mark bits, and the other three are space bits. This allows for the detection of single-bit errors.
Technical details
The number of possible valid binary code values in CCIR 476 is the number of ways to choose 4 marks for 7 bit positions, and the number can be calculated using the binomial coefficient: Thus CCIR 476 has 3 additional code points available over ITA2's 32 code points.
The SITOR protocol uses the additional three code points (denoted as SIA, SIB and RPT below) for idle, phasing, and repeat requests. In addition, some of the ordinary characters are reused as control signals.
Character set
In these tables, the hexadecimal code values are converted from a binary representation, with 1 being mark, 0 being space, and the most significant bit given first. The international version of ITA2 is used here; note also the added non-ITA2 codes SIA, SIB and RPT, used by SITOR.
References
Character encoding
Character sets
Telegraphy
Amateur radio | CCIR 476 | [
"Technology"
] | 288 | [
"Natural language and computing",
"Character encoding"
] |
62,092,666 | https://en.wikipedia.org/wiki/Online%20Harms%20White%20Paper | The Online Harms White Paper is a white paper produced by the British government in April 2019. It lays out the government's proposals on dealing with "online harms", which it defines as "online content or activity that harms individual users, particularly children, or threatens our way of life in the UK, either by undermining national security, or by reducing trust and undermining our shared rights, responsibilities and opportunities to foster integration", but excluding harm to businesses, harm from data breaches, and harm caused by activity on the dark web, all of which are dealt with by other government initiatives.
The government's proposed solution to these problems is to introduce a wide-ranging regime of Internet regulation in the United Kingdom, enforcing codes of practice on Internet companies, which would be subject to a statutory duty of care, and the threat of punishment or blocking if the codes are not complied with.
Following the abandonment of the proposed UK Internet age verification system in October 2019, the Culture Secretary Nicky Morgan stated that the government would seek to follow the White Paper's approach to regulation as an alternative.
See also
Media regulation
Online Safety Act 2023
Self-censorship
Web blocking in the United Kingdom
The Sex Workers Union
References
External links
https://www.gov.uk/government/consultations/online-harms-white-paper
White papers
Mass media regulation
Social media
2019 in the United Kingdom
Internet censorship in the United Kingdom
2019 documents | Online Harms White Paper | [
"Technology"
] | 294 | [
"Computing and society",
"Social media"
] |
70,221,526 | https://en.wikipedia.org/wiki/Pedersen%20process | The Pederson process is a process of refining aluminum that first separates iron by reducing it to metal, and reacting alumina with lime to produce calcium aluminate, which is then leached with sodium hydroxide. It is more environmentally friendly than the more well-known Bayer process. This is because instead of producing alumina slag, also known as red mud, it produces pig iron as a byproduct. Red mud is considered both an economic and environmental challenge in the aluminum industry because it is considered a waste, with little benefit. It destroys the environment with its high pH, and is costly to maintain, even when in a landfill. Iron, however, is used in the manufacture of steel, and has structural uses in civil engineering and chemical uses as a catalyst.
History
The Pedersen Process was invented by Harald Pedersen in the 1920s and used in Norway for over 40 years before shutting down due to the Pedersen Process being less economically competitive than the Bayer Process. However, it is believed a modern Pedersen process could be economically viable with "low-quality" bauxite, as even though "low-quality" bauxite has less alumina in the form of trihydrate gibbsite, it has more iron oxide which would be converted to pig iron in the smelting process instead of red mud.
Use in aluminum smelting
In most of today's smelting, aluminum ore, also known as bauxite, is first smelted into alumina through the Bayer Process. This step could be replaced by the Pedersen process -- either result in alumina. Unlike the smelting processes of iron and coal into steel or copper and tin into bronze, which require thermal energy, alumina must be smelted with electrical energy. This is done through the Hall–Héroult process, producing 99.5–99.8% pure aluminum.
References
Aluminium industry
Metallurgical processes
Chemical processes | Pedersen process | [
"Chemistry",
"Materials_science"
] | 399 | [
"Metallurgical processes",
"Metallurgy",
"Chemical processes",
"nan",
"Chemical process engineering"
] |
70,221,815 | https://en.wikipedia.org/wiki/Zeorin | Zeorin is a triterpene with the molecular formula C30H52O2 which occurs in many lichens.
References
Further reading
Lichen products
Pentacyclic compounds
Diols
Zeorin
Secondary alcohols
Tertiary alcohols | Zeorin | [
"Chemistry"
] | 50 | [
"Natural products",
"Lichen products",
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
70,221,943 | https://en.wikipedia.org/wiki/Skeletonema%20costatum | Skeletonema costatum is a cosmopolitan centric diatom that belongs to the genus Skeletonema. It was first described by R. K. Greville, who originally named it Melosira costata, in 1866. It was later renamed by Cleve in 1873 and was more narrowly defined by Zingone et al. and Sarno et al. Skeletonema costatum is the most well known species of the genus Skeletonema and is often one of the dominant species responsible for red tide events.
The diatom S. costatum is known for its carbon acquisition mechanisms, and it has been used in the production of biofuel and as a feed for aquaculture. The organism is appealing for commercial use due to its high photosynthetic efficiency, high tolerance to pH, temperature, and salinity changes, high lipid and fatty acid content, and rapid growth rate.
Structure and morphology
Cells belonging to S. costatum are single-celled but exist as long chains of about 6 to 24 cells but can be up to 60 cells in length. As with all diatoms, the siliceous cell wall (frustule) consists of two interlocking components ("like two halves of a petri dish"), the hypotheca and the epitheca. Each cell is approximately 8 to 12 μm in diameter and about 3.5 to 11.5 μm apart from each other. The cells are connected by long straight fultoportula processes and contain up to 2 chloroplasts per cell. Processes are tube-like silicified projections that protrude from the valve wall. Fultoportula processes, also known as strutted processes, protrude through the valve wall with 2 or more satellite pores surrounding them. Fultoportula processes are only found in the centric order Thalassiosirales. Each fultoportula process in S. costatum has 3 satellite pores and terminal fultoportulae processes with claw-like tips.
Cells belonging to S. costatum are cylindrically-shaped cells and have a ring of long flattened intercalary fultoportula processes protruding from the periphery of each valve, each closed along their entire length. Each intercalary fultoportula has a longitudinal suture extending from an external pore at its base to its tip.
Intercalary fultoportula processes of adjacent valves are connected at a 1:2 junction, where each process interlocks with two more, creating a "zigzag appearance". This 1:2 junction is a distinctive feature of S. costatum. Their intercalary rimoportula are positioned marginally, they have long terminal rimoportula, and their girdle band features rows of pores. Each valve has one of their fultoportulae replaced with a rimoportula, identified by its longer external process and the "spoutlike teapot"-shaped tip of the terminal rimoportulae.
Morphologically similar species
Among species in the genus Skeletonema, S. costatum is most morphologically similar to S. subsalsum, with both species exhibiting rows of small pores between the parallel rows of transverse branching ribs on their girdle bands. They are also the only two Skeletonema species with long intercalary rimoportula processes. Diatoms in the species S. costatum can be identified by the persistent presence of a 1:2 junction, and the closed tubules of its intercalary fultoportulae processes. Skeletonema subsalsum will sometimes have a 1:1 junction.
Morphological variation
The morphological plasticity of S. costatum cells has been extensively studied. Castillo (1995) attributes significant variations in morphological features, such as cell diameter, number of cells per chain, and the length of intercalary processes, with variations in environmental conditions, most notably, salinity. If cultured in freshwater, S. costatum develops short intercellular processes and is observed to seemingly not have space between sibling valves at 1 psu.
Taxonomy
As of 2021, 21 species in the genus Skeletonema were "identified and taxonomically accepted", with S. costatum being one of them.
Skeletonema costatum was first described by R. K. Greville in 1866 when it was originally called Melosira costata. It was later renamed by Cleve in 1873. Skeletonema costatum has since been more narrowly defined, with numerous species previously attributed to S. costatum identified as distinct species.
The species originally described by Greville is often referred to as S. costatum sensu lato (s. l.), which represents multiple different species with similar morphological traits. The species granted the original epithet, costatum, was the species more narrowly described by Zingone et al. (2005) after reexamination of the type materials of S. costatum using electron microscopy and molecular analysis of rDNA. Zingone et al. (2005) identified two distinct morphologies within the type material, describing the less abundant morphology as S. grevillei and the more abundant morphology as the original epithet, costatum. The latter was assigned the original epithet due to its closer similarity to the specimen originally described by Greville, which he had conveniently marked. The two morphologies differed in their frustule ultrastructures, including "the shape of FPPs [fultoportula processes], the type of interlocking between IFPPs [intercalary fultoportula processes] of sibling valves, and the cingular band ornamentation". S. costatum sensu stricto (s. s.) can be used to describe the more narrowly defined S. costatum species to differentiate it from S. costatum sensu lato. S. costatum sensu stricto (s. s.) has also been referred to as S. costatum (Greville) Cleve emend. Zingone and Sarno.
Distribution and habitat
Skeletonema costatum is widely distributed geographically, apart from the Antarctic Ocean. It is found around the world, including off the coasts of Hong Kong Island, Florida, USA, Uruguay, Brazil, Northern Queensland, Australia, China, and the Sea of Japan.
Skeletonema costatum primarily resides in the neritic zone and is commonly found in brackish waters as opposed to the more oceanic, S. tropicum. Skeletonema costatum is frequently the dominant phytoplankton species in coastal waters and the dominant species responsible for red tide events. Although the dominant species in red tide events at a given area can change over time, there are studies on red tide events in China in which S. costatum was dominant. This include the Yangtze River estuary in the interior of China, Hongsha Bay of Sanya in the South China Sea, and in Fujian coastal waters.
Yangtze River Estuary red tide outbreaks
Skeletonema costatum is one of the dominant species responsible for red tide outbreaks and blooms frequently occur in the Yangtze River estuary and adjacent waters in China. Of the red tide outbreaks in the Yangtze River estuary between 1972 and 2009, S. costatum occurred during 20% of the 174 recorded outbreaks. Over 50% of the outbreaks in this area occurred during May. After 2000, outbreaks of areal extents larger than 1000 km2 became more common. Nutrient applications from floods, fertilizers and other anthropogenic contributions in this area are suspected to have contributed to the blooms.
Growth and environmental conditions
Temperature
Skeletonema costatum grows at a range temperatures from 2 to 31.5 °C, but members of this species grow optimally at 25 °C. The strains of S. costatum from the Sea of Japan off the coast of Dōkai Bay prefer warmer temperatures, and are only collected from water above 20 °C. At this temperature, their specific growth rates were measured as above 1.0 d−1.
Salinity
Skeletonema costatum can grow in salinity conditions of 0 to 35 psu. As such, S. costatum can thrive in a variety of ocean environments ranging from oceanic to marine estuary and even riverine environments. Its optimal growth was found to be at a salinity range of 18 to 35 psu. The salinity tolerance of S. costatum is especially ideal in estuariane waters where salinities fluctuate, corroborated by the presence of this diatom as one of the dominant species in estuaries.
Although some strains of S. costatum such as SZN B202 exhibit rapid growth rates in salinities of 1 to 2 psu, members of this species generally show decreased growth outside its optimal salinity range. Decreased number of cells in a chain or decreased distance in between cells is observed at stress salinity conditions.
Light levels
Skeletonema costatum is most likely to grow under conditions of high illumination. The highest growth rate was found to be 1.6 x 1016 quanta s−1cm−2, but there is still a positive growth rate in low-light conditions of about 0.02 x 1016 quanta s−1cm−2. There is some debate over the different Skeletonema species and their classification, as many of these different species within the genus bloom in different seasons around the world. S. costatum is a highly adaptable species, and it has the potential to bloom during all seasons. This diatom is more dependent on the water quality than photoperiod lengths for bloom formation, though it is especially common to have a large bloom during the early spring and late summer.
High exposure to UVB radiation can have dramatic effects on the quality of S. costatum as a food source to marine invertebrates, marked by a decrease in fatty acid and amino acid contents of the individual S. costatum cells in these conditions.
The high partial pressures of dissolved CO2 associated with climate change have a positive effect on the growth rate of S. costatum in the spring and fall when there is equal parts light and dark in a day (12h light:12 h dark). The high partial pressure of CO2 was also found to reduce the growth rate of S. costatum in the winter (8h light:16h dark) but had no effect on its growth rate in the summer (16h light:8h dark).
At 20 °C, S. costatum can grow under irradiance of 7 to 406 μmol/m2s. Photoinhibition is observed at 700 μmol/m2s, at which point a decrease in photosynthetic ability of the diatom is detected.
Nutrients
Skeletonema costatum blooms in eutrophic waters that are often loaded with nitrogen, phosphorus, and other nutrients/minerals in both dissolved and particulate forms. The eutrophic conditions that house S. costatum blooms are often limited in carbon dioxide, as there is heavy competition for this limiting resource. It has been shown that nitrate enrichment and waters high in nitrate have the ability to stimulate S. costatum growth through the action of enhanced competitive photosynthetic activity in a CO2-limited environment. Phosphate can also be a limiting nutrient to S. costatum as phosphate-rich waters were found to have a stimulating effect on S. costatum growth rates in CO2-limited environments. High concentrations of nitrates and phosphates increase the amount of inorganic carbon in the form of bicarbonate fixed by S. costatum.
Iron is an essential nutrient in primary production as it is used in processes of photosynthesis and is under high competition among marine diatoms. One of the reasons S. costatum is able to outcompete other primary producers is its relatively high uptake rates of iron. S. costatum also has a low cellular demand for iron and is able to obtain this nutrient more efficiently than other phytoplankton.
Major viral pathogens
Skeletonema costatum-infecting virus (ScosV)
Skeletonema costatum-infecting virus (ScosV) is a novel algal virus isolated in 2008 from seawater samples taken in Jaran Bay, South Korea, which infects and lyses specific strains of S. costatum, particularly ME-SCM-1. In 2015, it was characterized as having an icosahedral shape and a diameter of approximately 40 to 50 nm. Upon infection of S. costatum, ScosV spends about less than 48 to 80 hours reproducing in the cytoplasm before causing lysis of host cells at a burst size range of 90 to 250 infectious units/cell.
Ecological significance
Marine diatoms account for about 20% of the world's primary production and considering that S. costatum is one of the most abundant species blooming in the ocean indicates that it is one of the major producers of oxygen. Skeletonema costatum plays an important role in the acquisition of both organic and inorganic carbon, in the form of HCO3−, in our oceans, collecting CO2 out of the atmosphere and reducing the effects of ocean acidification.
Eutrophic waters, as a result of aquaculture operations in nearshore marine environments such as shrimp farms, create especially favorable conditions for S. costatum growth. It has been reported that S. costatum-dominated red tide algal blooms in these eutrophic waters have led to considerable depletion of phosphate that remained at a low level for a long time after the bloom disappeared. These conditions lead to decreased abundance in other phytoplankton species and have potential in impacting the ecosystem in the area where the bloom occurs.
It has been suggested that S. costatum may be useful in the remediation of heavy metals from ocean ecosystems as it has a high affinity for iron and other heavy metals like manganese.
Human applications
Aquaculture feed
Skeletonema costatum has been cultivated for use in aquaculture as feed for fish, shrimp, oysters, crab larvae, and more.
Production of biofuels
Skeletonema costatum is used in biofuel production because of its high lipid and fatty acid content, rapid growth rate, high photosynthetic efficiency, and high tolerance to variations in pH, temperature, and salinity levels. When exposed to stress conditions such as depleted silicon and phosphate concentrations and high irradiation, it produces neutral lipids like triacylglycerol (TAG) which are ideal for making biofuel. These TAGs are extracted and converted to fatty acid methyl esters (FAME), which are molecules comprising the biofuel, using direct transesterification.
Production of natural products
Skeletonema costatum is also a source of natural products, which are secondary metabolites produced by microorganisms that can be used in pharmaceutical applications. The extracts of this diatom were found to have prospective use as a central nervous system relaxant that acts like an anti-dopaminergic drug with anticholinergic effects. It also has potential as an antipsychotic drug. Aside from these, antibacterial active compounds extracted from S. costatum using ethanol and methanol were also found to inhibit certain human pathogens, such as Staphylococcus aureus, Proteus mirabilis, and Vibrio cholerae.
References
Wikipedia Student Program
Thalassiosirales
Marine microorganisms
Protists described in 1866
Diatom species | Skeletonema costatum | [
"Biology"
] | 3,169 | [
"Marine microorganisms",
"Microorganisms"
] |
70,223,505 | https://en.wikipedia.org/wiki/Grigory%20E.%20Volovik | Grigory (or Grigori or Grigorii) Efimovich Volovik (Григорий Ефимович Воловик; born 7 September 1946 in Moscow) is a Russian theoretical physicist, who specializes in condensed matter physics. He is known for the Volovik effect.
Education and career
After graduating in 1970 from the Moscow Institute of Physics and Technology, Volovik became a graduate student at Moscow's Landau Institute for Theoretical Physics, where his received his Russian Candidate of Science degree (Ph.D.) in 1973. His thesis was on Dynamics of a particle strongly interacting with a Bose System. He has held since 1973 an appointment as a staff member of the Landau Institute and since 1993 a simultaneous appointment as a professor at the Low Temperature Laboratory (now called the Olli Lounasmaa Laboratory) at the Helsinki University of Technology (now called Aalto University). In 1981 he received from the Landau Institute his Russian Doctor of Sciences degree (habilitation). His Russian doctoral thesis was on Topology of defects in condensed matter. He is the author or co-author of over 450 research publications.
Volovik won in 1992 the Landau Gold Medal. He received in 2004 the Simon Memorial Prize "for his pioneering research on the effects of symmetry in superfluids and superconductors and for extending theses concepts to quantum field theory, cosmology, quantum gravity and particle physics." In 2014 he shared the Lars Onsager Prize with Vladimir Petrovich Mineev for "their contribution to a comprehensive classification of topological defects in condensed matter phases with broken symmetry, culminating in the prediction of half-quantum vortices in superfluid He-3 and related systems." Volovik was elected in 2001 a foreign member of the Finnish Academy of Science and Letters and in 2007 of the German Academy of Sciences Leopoldina.
Volovik's research deals with low temperature quantum spin liquids (such as liquid helium), superfluids, unconventional superconductivity (e.g. in systems of heavy fermions), the physics of glasses and liquid crystals, quantum turbulence, intrinsic quantum Hall effect, coherent states in the Larmor precession. He proposed ideas and novel experiments to investigate analogies between phenomena of quantum field theory and astrophysics and phenomena of solid state physics. He proposed a solution to the problem of the cosmological constant from analogies to solid state physics, in which, unlike particle physics and quantum gravity, the microscopic model is precisely known. In 2010 with Frans R. Klinkhamer, he published Towards a solution of the cosmological constant problem.
Volovik collaborated with the experimentalist Yuri Mikhailovich Bunkov on the study of particle physics analogues and phenomena in helium-3. In quantum field theory, liquid helium-3 is a good model of the vacuum state in elementary particle physics, with fermions as elementary excitations and bosons such as photons, gravitons, gluons as collective ones. According to Volovik's research, excitations and fundamental physical symmetry laws such as gauge and Lorentz invariance are "emergent" laws at sufficiently low temperatures. His view of the emergence of gravitation as a collective vacuum excitation stands in Russia in the tradition of a theory by Andrei Sakharov. In the case of helium-3, this is expressed by the loss of symmetry at high energies (gas) and the formation (emergence) of symmetries such as translational invariance in the superfluid state at low temperatures. There are phenomena in between a phase with global U(1) and two SO(3) symmetries and, at even lower temperatures, in the A-phase additional symmetries which, according to Volovik, are analogous to those observed symmetries (i.e., Lorentz and gauge symmetries and general covariance) of the Standard Model. Volovik calls the latter phenomenon "anti-GUT".
He investigated many-body problems from the point of view of classifying their properties as topological defects. In 2007 he published a Fermi point scenario making the assumption that gravity is "an emergent low-energy phenomenon arising from a topologically stable defect in momentum space". He did research on the topological invariants of the Standard Model and the possible topological quantum phase transitions that occur between the Standard Model's vacuum states.
In the first decade of the 21st century he served on the steering committee of the European Science Foundation's program Cosmology in the Laboratory (COSLAB).
Books
The Universe in a Helium Droplet. Clarendon Press, Oxford 2003; hbk ; 2009 edition. (over 3000 citations)
Exotic properties of superfluid 3He. World Scientific 1992.
with Mário Novello and Matt Visser (eds.): Artificial Black Holes. World Scientific, 2002 (with a chapter by Volovik: Effective Gravity and quantum vacuum in superfluids), pp. 127–178
with R. Huebener and N. Schopohl (eds.): Vortices in unconventional superconductors and superfluids. Springer Verlag, 2002; 2013 edition (with an introduction by Volovik: The beautiful world of the vortex, pp. 1–4)
References
External links
1946 births
Living people
Moscow Institute of Physics and Technology alumni
Landau Institute for Theoretical Physics alumni
Academic staff of Aalto University
20th-century Russian physicists
21st-century Russian physicists
Soviet physicists
Condensed matter physicists
Russian theoretical physicists
Members of the Finnish Academy of Science and Letters
Members of the German National Academy of Sciences Leopoldina
Russian expatriates in Finland | Grigory E. Volovik | [
"Physics",
"Materials_science"
] | 1,183 | [
"Condensed matter physicists",
"Condensed matter physics"
] |
70,223,845 | https://en.wikipedia.org/wiki/Hen%202-131 | Hen 2-131 is a planetary nebula in the southern constellation of Apus. It was discovered by Andrew David Thackeray in 1950 and added to the Catalogues of Hα-emission Stars and Nebulae in the Magellanic Clouds by Karl Gordon Henize in 1967.
Hen 2-131 is about 2,200 pc from earth. HD 138403 is the star located in the center of Hen 2–131 with a spectral type of O8(f)ep. The nebula expands at a speed of 11.5 km/s, and the temperature of HD 138403 is about . HD 138403 is suspected of variability, possibly by 0.1 to 0.15 magnitudes over a period of several hours. This nebula is similar to IC 418, IC 4593 and Hen 2-138.
References
Hen 2-131
Hen 2-131
Emission-line stars
O-type stars | Hen 2-131 | [
"Astronomy"
] | 187 | [
"Nebula stubs",
"Apus",
"Astronomy stubs",
"Constellations"
] |
70,223,861 | https://en.wikipedia.org/wiki/Decome | is an email feature available on Japanese mobile phone services that allows users to use an online rich-text editor so that they can include decorative images (such as emoji), animations, and backgrounds in their email messages, which are encoded as HTML emails. The feature was first created by NTT Docomo as , later being adopted by other Japanese mobile phone services under different brand names. is a part of Japanese mobile phone culture and was widely used in the 2000s.
History
NTT Docomo first introduced Deco Mail as a feature to send emails on mobile phones with an online rich-text editor, which allowed users to customize and add decorative images, emojis, and backgrounds to their emails. The emails are encoded in and sent as HTML emails. emoji are often used simply as an image or as a replacement for words. emoji are 20 × 20 pixels in size. The emoji can be customized and downloaded from other websites.
The feature was later adopted by other Japanese mobile phone services under different brand names, such as Decoration Mail (Au), Decore Mail (SoftBank), and Decorative Mail (Willcom). To the public, It became colloquially known as "decoration mail," or for short. When NTT Docomo introduced their FOMA 906i model, users were able to embed Adobe Flash videos in their messages, known as .
In a 2010 study, 4.3% of all emails sent by women consisted of emoji, while men used it in 2.0% of their emails. In 2012, social media and messaging apps became popular with users, particularly Line, which allow users to use stickers and emoji. Since then, has largely declined from the widespread adoption of smartphones and messaging apps.
References
External links
Japanese popular culture
Japanese writing system
Mobile phone culture
NTT Docomo
Wasei-eigo | Decome | [
"Technology"
] | 384 | [
"Members of the Conexus Mobile Alliance",
"NTT Docomo"
] |
70,224,579 | https://en.wikipedia.org/wiki/Sunobinop | Sunobinop (developmental code names V117957; IMB-115) is a high affinity small molecule nociceptin receptor partial agonist.
As of February 2024, it is under clinical investigation for the treatment of insomnia/alcohol use disorder, interstitial cystitis, and overactive bladder syndrome. It was previously also under investigation for the treatment of fibromyalgia.
Pharmacology
Sunobinop has nanomolar affinity (K) and efficacy (EC) at human recombinant nociceptin/orphanin-FQ peptide (NOP) receptors. It has a high degree of functional selectivity for the NOP receptor. Sunobinop is a low affinity antagonist at human mu and kappa opioid receptors, and is a low affinity weak partial agonist at human delta opioid receptors.
Clinical trials
Sunobinop was generally well tolerated in 3 studies involving 70 healthy subjects at doses that ranged from 0.6 to 30 mg. The most prominent adverse event was dose-dependent sedation/somnolence, which was more common at doses greater than 10 mg. In these studies, most of the absorbed sunobinop was excreted unchanged via rapid renal elimination.
The safety and effectiveness of sunobinop has not been evaluated by the FDA. There is no guarantee that sunobinop will successfully complete development or gain FDA approval.
See also
List of investigational sleep drugs § Nociceptin receptor agonists
Nociceptin receptor
References
Bridged heterocyclic compounds
Carboxylic acids
Experimental psychiatric drugs
Nociceptin receptor agonists
Quinoxalines | Sunobinop | [
"Chemistry"
] | 348 | [
"Carboxylic acids",
"Functional groups"
] |
70,225,312 | https://en.wikipedia.org/wiki/Priyadaranjan%20Ray | Priyadaranjan Ray FNA, FIAS (16 January 1888 – 11 December 1982) was an Indian inorganic chemist and historian of chemistry noted for proposing the Ray-Dutt twist mechanism.
Life and career
Ray was born in Chittagong District, Bengal Presidency (now in Bangladesh) to a zamindar family originally from Hooghly district (now in West Bengal), which had first migrated to the princely state of Tripura in the late 17th century, and had subsequently entered the service of the Nawabs of Bengal. The family were granted the estate of Noapara in the early 18th century by Nawab Murshid Quli Khan, the first Nawab of Bengal. After matriculating with distinction from the Chittagong Collegiate School in 1904, Ray secured a scholarship to the Chittagong Government College and in 1906 joined the Presidency College Calcutta as an undergraduate. He secured an honours degree in chemistry and physics in 1908, and then studied under Prafulla Chandra Ray for his master's degree, which he secured with the highest honours in 1911.
In 1911, Ray began work under P. C. Ray as a senior research scholar in inorganic chemistry. He began a research project on the formation of chemical complexes between Copper(I) thiocyanate and potassium thiocyanate, but on 12 August 1912, he was severely injured in an explosion when potassium thiocyanate reacted with hot sulfuric acid; the accident left him completely blind in his left eye and deprived him of most of the sight in his right. After two years of recuperation, he joined the City College, Kolkata as a chemistry professor. In 1919, he was appointed assistant professor of inorganic chemistry in the University Science College (now the Rajabazar Science College) of the University of Kolkata, where he remained until his retirement in 1952, being appointed Khaira Professor of Chemistry in 1937 and Palit Research Professor of Chemistry in 1946. Apart from a trip to Europe in 1929–1930, where he worked with Fritz Ephraim and Frederic Emich and underwent surgery to improve his remaining vision, he never left India.
Ray was a founding fellow of the Indian Chemical Society in 1924, serving as its president in 1947–1948. From 1945 to 1953, he served as the Honorary Director (Honorary Secretary until 1947) of the Indian Association for the Cultivation of Science (IACS), and again as its officiating Director from 1956 until 1958, when he largely retired from scientific research, having supervised a number of doctorates. In 1951, in recognition of his accomplishments in microchemistry and colorimetry, he was appointed a member of a IUPAC Commission of New Reactions and served for eight years, during which time he contributed towards a comprehensive review of colorimetric analysis. In 1979, he was appointed President of the 20th International Conference on Coordination Chemistry.
A bachelor, Ray lived simply and remained indifferent towards academic honours and distinctions throughout his life, never aspiring to a doctorate despite a record of accomplishments which would have qualified him for one. In 1935, he was appointed a Foundation Fellow of the National Institute of Sciences of India (FNI, now the Indian National Science Academy). In 1944, he was further appointed a Fellow of the Indian Association for the Cultivation of Science (FIAS). Completely blind and deaf in his final years, he died on 11 December 1982 after a period of failing health, aged 94.
Scientific and historical studies
During his career, Ray conducted research in coordination chemistry and magnetochemistry. He designed several organic
reagents including rubeanic acid, bismuthiol-I and biguanide for detecting and estimating metal ions with volumetric, gravimetric and spectrophotometric methods. A great deal of his work concerned the chemistry of the biguanide ligand, in connection with which he discovered its third- and fourth-order inner metallic complexes and proposed the rhombic-tetragonal Ray-Dutt twist mechanism with his colleague Nihar Kumar Dutt; the mechanism was intended to explain the racemization of tris(BigH)cobalt(III) ion, [Co(BigH)3]3+. Ray also conducted research into the higher oxidation states of metals and the polyhalogen compounds of hydrogen. Also a noted historian of Indian science, Ray published and edited a number of works on popular science and the history of Indian chemistry in both English and Bengali; after his retirement from the IACS in 1958, he continued to conduct and direct historical research as a supervisor of the History of Science Section of the Indian National Science Academy.
Global policy
He was one of the signatories of the agreement to convene a convention for drafting a world constitution. As a result, for the first time in human history, a World Constituent Assembly convened to draft and adopt the Constitution for the Federation of Earth.
Notes
References
1888 births
1982 deaths
Bengali chemists
20th-century Indian chemists
Indian inorganic chemists
People from Chittagong District
Chittagong College alumni
Presidency University, Kolkata alumni
Academic staff of Presidency University, Kolkata
University of Calcutta alumni
Academic staff of the University of Calcutta
Scientists from Kolkata
Fellows of the Indian National Science Academy
World Constitutional Convention call signatories | Priyadaranjan Ray | [
"Chemistry"
] | 1,060 | [
"Inorganic chemists",
"Indian inorganic chemists"
] |
70,230,066 | https://en.wikipedia.org/wiki/Nu%20Mensae | Nu Mensae, Latinized from ν Mensae, is a solitary star situated in the southern circumpolar constellation Mensa. It has an apparent magnitude of 5.76, making it faintly visible to the naked eye. The star is relatively close at a distance of 176 light years but is receding with a heliocentric radial velocity of .
Nu Mensae has a stellar classification of F0/2 III, indicating that it is a giant star with a spectrum intermediate between that of an F0 and F2 star. The star has an angular diameter of , and a radius 2.39 times that of the Sun at its estimated distance. At present it has 169% the mass of the Sun and shines at 11.5 times the luminosity of the Sun at an effective temperature of , giving it a white glow with a yellow tint. Despite an age of 1.7 billion years, Nu Mensae spins rapidly with a projected rotational velocity of and is slightly metal deficient relative to the Sun.
References
F-type giants
Mensa (constellation)
Mensae, 8
Mensae, Nu
Durchmusterung objects
029116
020297
1456 | Nu Mensae | [
"Astronomy"
] | 248 | [
"Mensa (constellation)",
"Constellations"
] |
70,230,834 | https://en.wikipedia.org/wiki/Rite%20%28Christianity%29 | In Christianity, a rite can refer to a sacred ceremony (such as anointing of the sick), which may or may not carry the status of a sacrament depending on the Christian denomination (in Roman Catholicism, anointing of the sick is a sacrament while in Lutheranism it is not). This use of rite is distinct from reference to liturgical ritual families such as the Byzantine and Latin liturgical rites.
Catholicism
Within the Catholic Church, "rite" often refers to what is also called a sacrament and respective liturgies based on liturgical languages and traditional local customs as well as the ceremonies associated with the sacraments. In Christian Catholicism, for example, the sacrament of Anointing of the Sick/Last Rites is one of the sacramental rites because they are administered to someone who is or was dying. The other are Penance and Eucharist (administered as Viaticum in the case of a dying person). Since the Second Vatican Council, anointing of the sick is administered to those who are seriously ill but not necessarily in immediate danger of death. Another example is the Rite of Christian Initiation of Adults. The term "rite" became widely used after the Second Vatican Council. While "rite" is often associated when receiving a "sacrament," it is technically incorrect to say that one received a "rite" because the sacrament is what is received while a rite is performed. The ritual consists of the prayers and actions that the minister of the sacrament performs when administering a sacrament. Therefore, it is incorrect to say that one has received "the last rites" as that person has really received "the last sacraments" by a minister following a ritual that has performed the "sacramental rite."
Protestantism
Within many Protestant Christian denominations, the word rite is often used specifically for important ceremonies that are not considered sacraments or ordinances. The 39 Articles of the Anglican Communion and the Articles of Religion of the Methodist Church state "there are two Sacraments ordained of Christ our Lord in the Gospel, that is to say, Baptism and the Supper of the Lord". As such, in the Anglican and Methodist traditions, the following are considered rites: "confirmation, reconciliation (confessions of sins), matrimony, holy orders and anointing of the sick". Similarly the "rites of the Moravian Church are Confirmation, Marriage, and Ordination". In the Lutheran tradition, Holy Baptism, Holy Eucharist, and Confession & Absolution are considered Lutheran sacraments, while Confirmation, Anointing of the Sick, Holy Matrimony, and Holy Orders are rites. As far as the liturgy is concerned, Western Lutheran churches use rites based on the Formula Missae while the Eastern Lutheran churches use the Byzantine Rite.
See also
Ritual
Funerary rites
Marriage rites
List of Christian liturgical rites
References
Ritual
Religious rituals
Christian worship and liturgy | Rite (Christianity) | [
"Biology"
] | 575 | [
"Behavior",
"Human behavior",
"Ritual"
] |
70,231,873 | https://en.wikipedia.org/wiki/Thomas%20Taylor%20%28microscopist%29 | Thomas Taylor (1820–1910) was a Scottish-American plant pathologist and microscopist. He was among the first to publish works on microscopic plant pathology with the USDA.
Taylor was born in Perthshire, Scotland. He immigrated to the United States at the invitation of Abraham Lincoln in 1851. In 1871, he was hired by the USDA and became head of microscopy. He was often criticized for his lack of professional training, and his work was discredited and buried by his colleagues. However, his research into fungal diseases of fruit was later praised.
Taylor died in 1910.
References
19th-century Scottish botanists
American phytopathologists
Microscopists
United States Department of Agriculture people
Scottish emigrants to the United States
People from Perthshire | Thomas Taylor (microscopist) | [
"Chemistry"
] | 156 | [
"Microscopists",
"Microscopy"
] |
70,232,248 | https://en.wikipedia.org/wiki/Bond%20Bridge | Bond Bridge is a Wi-Fi device that communicates with infra-red or RF controlled devices, such as ceiling fans, shades, and fireplaces. These devices often come with a battery powered remote control. The bond bridge receives commands form a network port, and it forwards the commands to the remote controlled device by simulating the signals the remote control would produce.
The photo shows a bond bridge in the dining room of Baywood Court, a senior community. The bond bridge controls ceiling fans in the dining room.
Broadlink RM4 is a competing product.
References
Computer networking | Bond Bridge | [
"Technology",
"Engineering"
] | 118 | [
"Computer networking",
"Computer science",
"Computer engineering"
] |
70,232,600 | https://en.wikipedia.org/wiki/Toilet%20meal | is a Japanese slang term and social phenomenon referring to the act of an individual eating a meal in a toilet room. In modern Japan, some people eat alone in a bathroom for various reasons, the most common being that they do not wish to be seen eating alone. Other reasons include saving money from eating out, to hide from co-workers in a busy workplace, or simply because they find it more comfortable.
Since toilet meals are often solitary and clandestine, others are unlikely to be aware of its occurrence. For this reason, "toilet meals" were initially regarded as an urban legend, but subsequent investigations have confirmed the phenomenon as relatively widespread. The term "toilet meal" has even been referenced in various popular media, most notably in various Japanese television shows.
Typical practice
Since private lavatory rooms are not designed for eating, eating postures vary from person to person. Typically people sit on the lid of a Western-style toilet-- this is the most natural posture for eating in a lavatory and is shown in most fictional portrayals. Other ways involve crouching in front of the toilet or standing in front of a Japanese-style squat toilet, which is at floor level. Alternatively, the person may crouch or squat in front of the toilet. In the case of a Japanese-style toilet, the food is rested on the knees; the lid of a Western-style toilet can be used as a table. 100 Most Popular Words in Japan says, "If you need to spread out your meal, lower the lid of the toilet bowl to make it look like a table. The disadvantage of this posture, however, is that it is very tiring, and the sight of the toilet seat and water tank can be distracting". This posture occurs in some fictional portrayals; for example, in episode 33 of the manga Zekkai Gakkyu, the main character Ohno eats squatting in a toilet room with a Japanese-style toilet.
Research
Social research has been conducted to find out how many people have eaten a meal on a toilet. Although figures vary depending on the survey, one survey conducted in 2013 found that 12.08% of respondents said they had eaten on the toilet, with a higher percentage of younger people and women.
In 2009, Naoki Ogi, a professor at Hosei University, surveyed 487 students and received 400 responses. 0.3% of the respondents answered that they ate toilet meals "often" and 2.0% of the respondents answered they ate "a little".
In a survey of 1,000 people conducted by Mynavi News in 2012, 7.1% said they had eaten meals in the toilet.
In a survey conducted by home renovation company SunRefreHoldings in 2013, out of 2,459 valid responses, 12% had eaten in a public restroom at home, school, or work. Of these same responses, 19% said they had eaten toilet meals in their 20s, 13% in their 30s, and 11% in their teens. Notably, 80% of women in their twenties stated they had eaten a "toilet meal", many of them in public restrooms.
In a 2015 nationwide survey of 1,500 Japanese men and women in their 20s to their 60s conducted by the news site Sirabee, 5.5% said they had eaten a toilet meal.
In a 2017 survey of 1,342 men and women in their 20s to 60s, also conducted by Sirabee, 10.2% said they had eaten in the toilet. 11.9% of men and 8.5% of women surveyed said they had eaten in the toilet. Of the reasons given were wanting to save money on lunch, having trouble refusing invitations, and being "cool and comfortable".
Law
In Japan, there are few laws regarding toilet meals, since they would be difficult to enforce. Some ways that it could pose legal enforcement would be if the occupant stays in the bathroom for a long time and prevents others from using it or leaving garbage and causing sanitary issues, however these have often been attributed to stomach issues, such as diarrhea.
Hygiene
Eating in a toilet is not desirable from a hygiene standpoint. According to the Training Manual for School Meal Preparation Personnel published by the Ministry of Education, Culture, Sports, Science and Technology, "Since various pathogenic microorganisms exist in stool and are excreted with stool during defecation, toilets are places with a high risk of being contaminated by pathogens that cause food poisoning. During defecation, there is a high possibility of the toilet bowl being contaminated by norovirus and other pathogens, and of toilet doorknobs, etc. being contaminated through the hands and fingers". The report devotes pages to lavatories as a place where food handlers need to take special care.
Fear of being seen as lonely
A toilet meal is often seen as embarrassing or a sign of social ineptitude. In Japanese social life, attractiveness is often measured by the number of friends a person has, and those who are seen as friendless are often evaluated negatively on that basis alone. Therefore, people who fear being perceived as friendless and unattractive secretly eat in the toilet. Daisuke Tsuji, an associate professor of sociology at Osaka University, wrote in Asahi Shimbun: "Those who fail to make friends within a limited relationship must continue to endure not only loneliness but also the gaze of being branded as a strange person with no friends. They are marginalized in a double sense. The only place left to escape the gaze is the private room in the bathroom". Tsuji believes that the solution to the problem is to "create an environment in which children and young people can form diverse relationships outside of their peer group, including a review of the class system", and that the problem of the toilet meal can be solved by supplementing multi-layered human relationships.
University response
There is a movement at universities to address the issue of students eating toilet meals from the perspective of interpersonal communication. When the issue was first reported, there was little awareness that it was occurring. In response to inquiries by Asahi Shimbun in 209, the University of Tokyo's public relations group said, "It may be that we just haven't noticed it, but we have never heard of it", and Meijo University's general policy department responded, "We don't recognize it, so we don't give any guidance".
In 2013, during an overnight orientation camp for new students, Shimane University's Faculty of Education circulated a questionnaire and found that 56.6% of the students were aware of the phrase "toilet meal". The department tried to reduce new students' problems by holding training sessions to build relationships with upperclassmen.
In a 2016 Kobe Gakuin University report on a survey of its own campus on "places to stay", 1.7% of students cited the restroom as a place to stay, citing Ninomiya's view that "we need to worry about situations such as 'toilet meal' by college students who eat lunch in the restroom" and, "We cannot deny the possibility that there are students at our university who consider the toilet to be their 'place of residence because they avoid interacting with others or are unable to relate well with others".
According to a counsellor at the Health Center of Hokkaido University, "There are actually students who eat their meals alone in the private rooms of the toilets", and those students who cannot eat alone because they are worried about being seen, they have an activity called "lunch meeting" where they eat their meals with the staff and talk about various topics.
The student counselling office of Tokyo Fuji University has reported that students have told them they eat in the toilet and that they advise students to "come to the student counselling office as soon as possible if you are troubled by such a thing".
See also
Bathroom reading
Toilets in Japan
Mariko Aoki phenomenon
References
External links
Toilets
Sanitation
Japanese home
Japanese architectural features
Health in Japan
Japanese mythology
Japanese urban legends | Toilet meal | [
"Biology"
] | 1,644 | [
"Excretion",
"Toilets"
] |
70,234,658 | https://en.wikipedia.org/wiki/System%20for%20Differential%20Corrections%20and%20Monitoring | The System for Differential Corrections and Monitoring (SDCM), is the satellite-based navigation augmentation system operated by Russia's Roscosmos space agency to augment the precision of the GLONASS satellite navigation system. It uses the Luch Multifunctional Space Relay System to transmit correction data.
SDCM's service area covers the Russian Federation. it had not yet been certified for use for public aviation.
References
External links
Design summary for SDCM, 2012
Navigation satellite constellations
Satellite-based augmentation systems | System for Differential Corrections and Monitoring | [
"Astronomy"
] | 110 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
56,049,586 | https://en.wikipedia.org/wiki/Geodetic%20Observatory%20Wettzell | The Geodetic Observatory Wettzell is located atop the 616 meter-high mountain Wagnerberg, west of the village Wettzell in the German district Cham in the Bavarian Forest.
Tasks
It is operated for the purpose of geodesy by the Federal Agency for Cartography and Geodesy together with the Technical University of Munich and is today one of the most important geodetic observatories in the world.
As observing station, the Geodetic Observatory Wettzell has the task of gathering measuring data for the geodetic space techniques VLBI, SLR, GNSS and DORIS. These data are used for realizing global coordinate reference systems that form the basis for numerous issues in the field of geosciences (e.g. continental drift, sea level rise), in aerospace, but also in areas of everyday life (e.g. surveying, navigation). These global tasks can today only be solved through international cooperation. The activities like observations, data flow, data analysis and provision of results are coordinated by the international services of the IAG, e.g. IERS, IVS (International VLBI Service), ILRS (International Laser Ranging Service), IGS (International GNSS Service) and IDS (International DORIS Service).
The Federal Georeference Data Act (German: Bundesgeoreferenzdatengesetz) is the legal basis for that.
Wettzell also supports the operation of the observatories AGGO in La Plata/Argentina and GARS O'Higgins in Antarctica.
Measurement equipment
At the site with an approximate size of 300 by 150 meters, you find all modern observation techniques of satellite or space geodesy and complementary measuring techniques, especially
a laser telescope for ranging to satellites and the Moon (WLRS)
a laser telescope for distance measurements to low-flying satellites with high temporal resolution (SOS-W)
a 20 m radio telescope for intercontinental VLBI measurements (RTW)
a twin system consisting of two 13 m radio telescopes, also for VLBI measurements (TTW-1 and TTW-2)
several Multi-GNSS receivers for continuous satellite measurements
a high-precision time system with several atomic clocks and hydrogen masers and a fibre-optic time distribution system with delay compensation
a ring laser in an underground observatory for monitoring the Earth's rotation
a beacon for the French Doppler system DORIS
a superconducting gravimeter
complementary measuring equipment for ground and atmosphere monitoring (seismometer, tiltmeter, hydrological sensors, climate station, water vapour radiometer, temperature profiler, cloud detector)
and facilities for administration and maintenance.
The reference points of the single measuring systems are linked by a local surveying network in order to obtain coordinate differences for a combination of the different techniques. This characteristic determines a geodetic fundamental station.
History
The Geodetic Observatory Wettzell was founded nearby the former Iron Curtain to former Czechoslovakia and to Germany's Air Defense Identification Zone in 1970 in order to have a night sky as dark as possible with only low light pollution and have to take little consideration of air traffic for Satellite and Lunar Laser Ranging.
The beginnings of the satellite observing station Wettzell go back to an early research project of the Technical University of Munich and the Institute for Applied Geodesy for optical observation and orbit determination of geodetic Earth satellites. The field of satellite geodesy newly arisen at that time promised great progress for global geodesy. The optical observations carried out until the end of the 1970s included images of satellite passages with the Zeiss Double Astrograph and the ballistic measuring camera Zeiss BMK 75 for satellite triangulation and observations with a circumzenithal and the Danjon Astrolab for astronomical longitude and latitude determination.
In cooperation with the German Test and Research Institute for Aviation and Space Flight (DFVLR, today's DLR), a first laser distance measuring system consisting of an anti-aircraft gun carriage and a ruby laser, was put in operation in 1972. With that, on 8 April 1973, the distance to a satellite (GEOS-1) was measured for the first time in Germany by laser. But only with the following, computer-adjusted systems SRS (Satellite Ranging System, 1977–1991) and WLRS (Wettzell Laser Ranging System, since 1991) large numbers of routine observations became possible. In addition, distances to the reflectors located at the Moon were already measured with the WLRS.
In the mid-seventies, the station was extended by microwave measuring techniques. Since 1974, Doppler measurements to satellites of the “Navy Navigational Satellite System” (N.N.S.S. or Transit) were performed regularly for point determination in geodesy. The first measurements to the satellite navigation system NAVSTAR GPS were already performed during the test phase 1979–1981 with Wettzell as one of four tracking stations worldwide. In 1993 the Doppler measurements ended, after the N.N.S.S. was replaced with the full development of GPS.
With implementing a radio telescope in 1983, the satellite observation station turned into a fundamental station of geodesy, where the various space geodetic techniques VLBI, SLR and GNSS are combined in one place. Since 2012, the observatory has two further so-called twin telescopes, in order to take account of technical progress and the increasing observation tasks.
See also
List of astronomical observatories
References
External links
Geodetic Observatory Wettzell (in German)
Flyer “Geodetic Observatory Wettzell”
Friends' association “Geodetic information centre Wettzell” (in German)
Radio telescopes
Astrometry
Astronomical observatories in Germany
Buildings and structures in Cham (district)
Geodesy organizations | Geodetic Observatory Wettzell | [
"Astronomy"
] | 1,192 | [
"Astrometry",
"Astronomical sub-disciplines"
] |
56,049,870 | https://en.wikipedia.org/wiki/Galactic%20superwind | A galactic superwind, or just galactic wind, is a high velocity stellar wind emanating from either newly formed massive stars, spiral density waves, or as the result of the effects of supermassive black holes. They are normally observed in starburst galaxies.
Description
Galactic winds are strong stellar winds made up of charged particles, ejecta, and varying amounts of hot and cool gas, interacting with enough force that the ejecta's kinetic energy is converted to thermal energy. The resulting effect is a massive gust of rapidly expanding super-heated gases that can span the length of a galaxy.
In galaxies with active galactic nuclei, galactic winds can also be driven by the effects of super-massive black holes.
Galactic winds are considered an important function in the evolution of a galaxy. The winds cause an outflow of gas and other material into the halo of a galaxy, while also facilitating the spread of metals around a galaxy. Galactic winds are also capable of blowing material out of a galaxy entirely and into the intergalactic medium.
Formation
Superwinds are theorized to form in compact starburst galaxies in which star growth is much higher than in other types of galaxies. This accelerated star growth results in more prevalent stellar winds being present in starburst galaxies. Superwinds form when ejecta released either by supernovae or stellar winds collide with such force that the shock from the impact converts the kinetic energy of the ejecta into thermal energy. The violent conversion from kinetic to thermal energy prevents a significant amount of energy from being radiated away. This in turn creates an incredibly hot bubble of gas that is under much greater pressure than it surroundings are. Eventually the gas bubble will expand to encompass other particles of ejected gases, further increasing the force and size of its expansion. This "snowplow" effect results in a gust of stellar wind and gas that can span the width of a galaxy. It has been theorized that superwinds can potentially be traveling at a velocity of several thousand kilometers per second by the time they enter the intergalactic medium.
See also
Cosmic wind
Stellar wind
Solar wind
Planetary wind
Stellar-wind bubble
Colliding-wind binary
Pulsar wind nebula
Superwind
References
Stellar evolution
Solar phenomena
Stellar phenomena | Galactic superwind | [
"Physics"
] | 455 | [
"Physical phenomena",
"Astrophysics",
"Stellar evolution",
"Solar phenomena",
"Stellar phenomena"
] |
56,050,266 | https://en.wikipedia.org/wiki/Kepler-90i | Kepler-90i (also known by its Kepler Object of Interest designation KOI-351.08) is a super-Earth exoplanet with a radius 1.32 times that of Earth, orbiting the early G-type main sequence star Kepler-90 every 14.45 days, discovered by NASA's Kepler spacecraft. It is located about 2,840 light-years (870 parsecs, or nearly km) from Earth in the constellation Draco. The exoplanet is the eighth in the star's multiplanetary system. As of December 2017, Kepler-90 is the star hosting the most exoplanets found. Kepler-90i was found with the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured, and by a newly utilized computer tool, deep learning, a class of machine learning algorithms.
Characteristics
Mass, radius and temperature
Kepler-90i is a super-Earth exoplanet with a radius of 1.32 , indicating that it is small enough to be rocky. With an Earth-like composition, Kepler-90i would have a mass of about 2.3 , since its volume is times that of Earth's. It has an equilibrium temperature of , similar to the average temperature of Venus.
Host star
The planet orbits Kepler-90, a G-type main sequence star. The star has a mass of 1.2 and a radius 1.2 . It has a surface temperatures of 6080 K and has an estimated age of around 2 billion years, with considerable uncertainty. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K.
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 14. It is too dim to be seen with the naked eye.
Orbital characteristics
Kepler-90i orbits its host star about every 14.45 days with a semi-major axis of 0.107 AU.
Due to its very close distance to its host star, it is likely to be tidally locked, meaning that one side permanently faces the star in eternal daylight and the other side permanently faces away from the star in eternal darkness.
Discovery
In 2009, NASA's Kepler spacecraft was observing stars on its photometer, the instrument it uses to detect transit events, in which a planet crosses in front of and dims its host star for a brief and roughly regular period of time. In its last test, Kepler observed stars in the Kepler Input Catalog, including Kepler-90; the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the bunch for follow-up at observatories. Discovery of the exoplanet was aided by a newly utilized computer tool, deep learning, a class of machine learning algorithms.
See also
Kepler-80g
References
Exoplanets discovered by the Kepler space telescope
Exoplanets discovered in 2017
Transiting exoplanets
Draco (constellation) | Kepler-90i | [
"Astronomy"
] | 618 | [] |
56,051,175 | https://en.wikipedia.org/wiki/Essential%20Biodiversity%20Variables | Essential Biodiversity Variables (EBVs) is a putative set of parameters intended to be the minimum set of broadly agreed upon necessary and sufficient biodiversity variables for at least national to global monitoring, researching, and forecasting of biodiversity. They are being developed by an interdisciplinary group of governmental and academic research partners. The initiative aims for a harmonised global biodiversity monitoring system. EBVs would be used to inform biodiversity change indicators, such as the CBD Biodiversity Indicators for the Aichi Targets.
The concept is partly based on the earlier Essential Climate Variables. It can be generalised as the minimum set of variables for describing and predicting a system's state and dynamics. Areas with more developed EV lists include climate, ocean, and biodiversity.
EBV Classes / Categories
The current candidate EBVs occupy six classes of Essential Biodiversity Variable: genetic composition, species populations, species traits, community composition, ecosystem structure, and ecosystem function. Within each class are a few to several variables.
Associated projects and organisations
As of 2017, participants in the project consist of the GlobDiversity project (funded by the European Space Agency) under GEO BON (Group on Earth Observations Biodiversity Observation Network; a cooperative project of international universities), and the GLOBIS-B project (Global Infrastructures for Supporting Biodiversity Research; funded by the EU Horizon 2020 programme).
Development
The concept was first proposed in 2012 and developed in the following years.
The GLOBIS-B global cooperation project, aimed to advance the challenge of practical implementation of EBVs by supporting interoperability and cooperation activities among diverse biodiversity infrastructures, started in 2015. The GlobDiversity project of GEO BON, led by the University of Zurich, started in 2017, focusing on specification and engineering of three RS-enabled EBVs.
The scope and screening of potential variables is under ongoing discussion.
This includes definition of the species distribution EBV and population abundance EBV, operationalisation of the EBV framework, data and tools for building EBV data products, workflow for building EBV data products, metadata and data sharing standards; and possible integration of abiotic variables (e.g. those emphasised in the Ecosystem Integrity framework) with biotic variables (emphasised in the EBV framework) to achieve comprehensive ecosystem monitoring.
"EBV data products" refers to the end product in the EBV information supply chain, from raw observations, to EBV-usable data, to EBV-ready data, to EBV data products. Each of these three types of EBV datasets could be used to produce indicators. Data sources for EBVs are categorised into four types: extensive and intensive monitoring schemes, ecological field studies, and remote sensing. Each have their own often complementary properties, implying that data integration will be important for creation of representative EBVs, as well as identifying and filling data gaps.
References
Biodiversity
International scientific organizations
Earth observation | Essential Biodiversity Variables | [
"Biology"
] | 608 | [
"Biodiversity"
] |
56,052,250 | https://en.wikipedia.org/wiki/Max%20Noether%27s%20theorem%20on%20curves | In algebraic geometry, Max Noether's theorem on curves is a theorem about curves lying on algebraic surfaces, which are hypersurfaces in P3, or more generally complete intersections. It states that, for degree at least four for hypersurfaces, the generic such surface has no curve on it apart from the hyperplane section. In more modern language, the Picard group is infinite cyclic, other than for a short list of degrees. This is now often called the Noether-Lefschetz theorem.
Algebraic geometry | Max Noether's theorem on curves | [
"Mathematics"
] | 112 | [
"Fields of abstract algebra",
"Algebraic geometry"
] |
56,052,525 | https://en.wikipedia.org/wiki/Linus%20%28fusion%20experiment%29 | The Linus program was an experimental fusion power project developed by the United States Naval Research Laboratory (NRL) starting in 1971. The goal of the project was to produce a controlled fusion reaction by compressing plasma inside a metal liner. The basic concept is today known as magnetized target fusion.
The reactor design was based on the mechanical compression of a molten metal liner. A chamber would be filled with molten metal and rotated along one axis, creating a cylindrical cavity in the center. A suitable fusion fuel, heated to several thousand degrees to form it into a plasma, is injected into the center of the cavity. The metal is then rapidly collapsed, and due to the conservation of magnetic flux within the metal, the plasma is confined within the resulting collapsing shell and is itself collapsed. The adiabatic process would raise the temperature and density of the trapped plasma to fusion conditions.
The use of a liquid metal liner has many advantages over previous Soviet experiments that imploded cylindrical solid metal liners to achieve high-energy-density fusion. The liquid metal liner provided the benefits of recovering the heat energy of the reaction, absorbing neutrons, transferring kinetic energy, and replacing the plasma-facing wall during each cycle. Added benefits of a liquid liner include greatly simplified servicing of the reactor, reducing radioactivity, protecting the permanent sections of the reactor from neutron damage, and reducing the danger from flying debris.
The concept was revived in the 2000s as the basis for the General Fusion design, currently being built in Canada.
Conceptual design
In the Linus concept, the reactor chamber consists of a drum filled with a liquid metal liner, typically molten lead-lithium. The drum is spun, creating centrifugal force which causes the liquid to be forced onto the inside wall of the container. There is only enough liquid metal to fill perhaps 20% of the total volume, so a large open area in the middle forms during rotation. For operation, a system, typically consisting of pistons, is used to drive additional liquid metal into the drum. This causes the entire liner to be forced inward. In experimental systems, this provided about ten-to-one compression. The extra metal is then removed again by releasing the pistons, causing the compression to reverse and the metal reach the original position at the outside of the drum.
To create fusion, a fusion-fuel plasma is injected into the cavity before the piston stroke. Because of magnetic interactions in the metal, the plasma in the cavity is forced inward as well. This compression causes the plasma temperature to increase through the adiabatic process, raising it to fusion-relevant temperatures and pressures, around 100 million K and . At these temperatures and pressures, the rate of fusion, according to the fusion triple product, is very rapid and completes before the mechanical compression reverses. The energy released by these reactions, in the case of the typical deuterium-tritium (D-T) fuel, is mostly in the form of high-energy neutrons about 14.1 MeV. These are captured in the liquid metal, raising its temperature. Some of the neutrons will interact with the lithium in the liner, undergoing a nuclear reaction that produces new tritium. In a functioning reactor, the energy would then be extracted using a steam generator as is the case in conventional heat driven power plants, while the tritium would be extracted through a variety of chemical processes.
A key advantage of the Linus concept is that the compression cycle is reversible, in contrast to other concepts that use thin solid metal shells that can only be used once. This allows the system to run continually, limited generally by the ability to clear out the results of the last reaction and generate and inject new fuel plasma, on a timescale of a few seconds. Additionally, systems using non-rotating shells are subject to the Rayleigh-Taylor instability and have proven extremely difficult to stabilize. The rotation of the liquid in Linus suppresses these instabilities. Finally, the metal protects the rest of the reactor from the neutron flux, which is a major problem in other designs.
History
The Linus effort ultimately traces its history to a discussion between Ramy Shanny of the United States Naval Research Laboratory (NRL) and Evgeny Velikhov of the Kurchatov Institute.
The basic idea of super-high magnetic fields as a path to fusion had been considered as early as the 1950s by Andrei Sakharov, who proposed imploding metal liners to produce the required field. The concept was not picked up until the 1960s, when Velikhov began small-scale experiments. It was realized that the cost of the metal liners would likely be higher than the value of the electricity they would produce, the "kopeck problem", and they considered the idea of using a liquid metal liner instead.
Shanny asked about how such a system would be stabilized against Rayleigh-Taylor issues. Velikhov misunderstood the question, thinking he was asking how it would be stabilized against gravity within the drum. He replied that they would spin it. Shanny, believing Velikhov was saying spinning would address Rayleigh-Taylor problems, performed the calculations and found that it did indeed stabilize these instabilities. The Linus program was born.
Suzy I
To gain experience with the concept, NRL initially built liner imploders. The first experimental device was Suzy, constructed in 1971 under the direction of D.C. dePackh. The system used solid metal liners, like the Soviet experiments and many later devices. The liner was driven inward through the theta pinch process, using a capacitor bank.
Suzy II
A.E. Robson and P.J. Turchi joined the program in 1972, and dePackh departed NRL. Robson and Turchi continued the development of the concept with Suzy II, a similar system to what then became Suzy I, but much larger and equipped with a larger capacitor bank power supply. Suzy II compressed liners from an initial diameter of to a final diameter of about , giving an overall compression ratio of 28:1. Pressures greater than were achieved during the implosions.
With the success of the Suzy II experiments, attention turned to the liquid liner. This was built on Suzy II using a plastic liner inside a steel drum, filled with sodium-potassium alloy (NaK) at its eutectic ratio (22% Na, 78% K) which is a liquid at room temperature. By firing the implosion bank at different powers, the relationship between implosion speed and rotation speed could be tested. As long as the rotational speed is high enough, as the liner compressed and its rotational speed increased due to conservation of angular momentum, the centripetal force kept the apparent gravity vector pointed outward. This stabilizes against R-T instabilities because it is the lighter fluid in the center falling outward, a naturally stable condition.
Suzy II was successful in producing a stable inward compression of the liner, but unfortunately, the reverse was not true. As the liner began to expand again when the compression current was turned off, it once again caused a heavy fluid to move into a lighter one, and the R-T instabilities reappeared. This caused the liner to break up into droplets, which, due to their high mass and velocity, impacted the container randomly with the entire embodied energy. In a production machine, this would be on the order of 100 MJ, the equivalent of about of TNT.
Piston implosion experiments
The solution to the liner breakup during expansion is to fill the void with additional liner material. This precludes the use of electromagnetic drivers as in Suzy, and attention turned to using a mechanical piston driving material from a reservoir into the main chamber. The piston was driven by compressed gas.
Several experimental machines followed. The first, the "water model", consisted of a drum of water with pistons positioned radially around it. The entire system spun, including the pistons. This verified the basic approach but was problematic as the piston timing proved difficult to control with the required accuracy. This problem was addressed by a new piston layout with the pistons arranged annularly that could be fired by a single source. This proved to solve the problems and plans began to build larger devices.
Linus-0
With the success of the piston models, plans began to build a larger machine similar to the size and energy as the Suzy II machine. This led to the Linus-0 design, which consisted of a diameter steel rotor surrounded by a gas cylinder that was pressurized to using a series of small high-explosive DATB () charges, also known as the polymer-bonded explosive PBXN, chosen for its high melting point, low particulate matter, and compatibly low cost. The charges were loaded into a series of ports on one end of the device and fired just before the experimental run to pressurize the system. The inner rotor was spun to using a 454 cubic inch Chevrolet V8 engine.
Linus-0 proved to be slow to build due to the only machine shop large enough to make the rotor being busy with other tasks, and the device was not completed until 1978, shortly before the program closed down. Nevertheless, the system was used with water and proved to be able to make repeatable shots in the short time it was operational. During data collection, Linus-0 was fired as often as three times daily.
Helius
The delays in the construction of Linus-0 led to the construction of a half-scale version, Helius. It was designed to use liquid sodium and potassium in the liner chamber. In practice, the use of water was sufficient for the hydrodynamic studies. In the experiment, the liquid sodium-potassium liners were imploded using high-pressure Helium () to drive mechanical pistons.
Project fate
The initial proposals for the Linus designs were based on the cylindrical collapse of the liner with a continuous plasma inside. This arrangement meant there was nothing to confine the plasma from being squirted out the ends of the imploding cylinder of metal. This was not necessarily a problem; both the liner and the plasma would move at the speed of sound, but because the speed of sound in the metal is much higher than in the plasma, most of the plasma would not have time to move before it had already completed the reaction. There was some concern about bad curvature at the ends of the cylinder, which can lead to the interchange instability that operates much faster than the speed of sound. The magnitude of this effect, if was present at all, was not explored.
The disadvantage of this approach was that some plasma did escape, and that amount increased as the speed of the implosion decreased. To get a reasonable reaction rate, driver energies on the order of were required. While this was not impossible to achieve, it still represented a significant capital cost to build such a storage system, and the resulting high-energy and high-speed implosion represented an engineering challenge.
Linus was being developed while another fusion concept was first emerging, the field-reversed configuration, or FRC. This is essentially a smoke ring of plasma that is naturally stable until it cools. Using an FRC inside the machine would provide natural confinement at the ends of the cylinder, preventing the plasma from escaping. This would significantly reduce the required implosion energy, and thus lower the size and cost of the machine as a whole.
At the time, FRCs were very new technology. But as they appeared to represent a significant advance in the state of the art, potentially making a successful fusion system even without the implosion, NRLs interest quickly changed to the underlying physics of the FRC. Experiments on Linus-0 and Helius were relatively brief due in part to delays incurred in the design, fabrication, and assembly phases. Time wasn't allocated to recover from delays or unexpected challenges, and the machines were eventually disassembled and placed in storage.
The Linus project encountered several engineering problems which limited its performance and thus its attractiveness as an approach to commercial fusion power. These issues included performance of the plasma preparation and injection method, the ability to achieve reversible compression–expansion cycles, problems with magnetic flux diffusion into the liner material, and the ability to remove the vaporized liner material from the cavity between cycles (within a duration of about ) which was not accomplished. Shortcomings also occurred with the design of the inner mechanism which pumped the liquid-metal liner.
Another major problem encountered involved hydrodynamic instabilities in the liquid liner. If the liquid was imprecisely compressed, the plasma boundaries could undergo Rayleigh–Taylor instability. This condition could quench the fusion reaction by reducing compression efficiency, and by injecting liner material (vaporized lead and lithium) contaminants into the plasma. Both effects reduce the efficiency of fusion reactions. Strong instability could even cause damage to a reactor. Synchronizing the timing of the compression system was not possible with the technology of the time, and the proposed design was canceled.
See also
Electromagnetic forming
General Fusion
Magnetized target fusion
Shiva Star
Notes
References
Bibliography
Nuclear power
Magnetic confinement fusion devices | Linus (fusion experiment) | [
"Physics",
"Chemistry"
] | 2,673 | [
"Physical quantities",
"Nuclear power",
"Power (physics)",
"Particle traps",
"Magnetic confinement fusion devices"
] |
56,054,391 | https://en.wikipedia.org/wiki/RD-162 | RD-162 is a second-generation nonsteroidal antiandrogen (NSAA) which was developed for the treatment of prostate cancer but was never marketed. It acts as a potent and selective silent antagonist of the androgen receptor (AR). The drug is a diarylthiohydantoin derivative. It is closely related to enzalutamide and apalutamide. Both RD-162 and enzalutamide show 5- to 8-fold higher affinity for the AR than the first-generation NSAA bicalutamide, and only 2- to 3-fold lower affinity than dihydrotestosterone (DHT), the major endogenous ligand of the receptor in the prostate gland.
RD-162 and enzalutamide were developed together and were derived from the nonsteroidal androgen RU-59063, which itself was derived from the first-generation NSAA nilutamide. RD-162 and enzalutamide were selected as the lead compounds from a group of over 200 compounds that were synthesized and assayed for antiandrogenic activity. Enzalutamide was ultimately selected from the two for further clinical development and was eventually marketed. RD-162 is also very closely related to apalutamide, with the two compounds differing only by the replacement of a single atom (a carbon atom in one of the phenyl rings of RD-162 swapped with a nitrogen atom in apalutamide). Apalutamide was approved for the treatment of prostate cancer in 2018.
References
Abandoned drugs
Benzamides
Fluoroarenes
Hormonal antineoplastic drugs
Ketones
Nitriles
Nonsteroidal antiandrogens
Spiro compounds
Thioureas
Trifluoromethyl compounds | RD-162 | [
"Chemistry"
] | 363 | [
"Ketones",
"Drug safety",
"Functional groups",
"Organic compounds",
"Nitriles",
"Abandoned drugs",
"Spiro compounds"
] |
56,054,658 | https://en.wikipedia.org/wiki/RU-59063 | RU-59063 is a nonsteroidal androgen or selective androgen receptor modulator (SARM) which was first described in 1994 and was never marketed. It was originally thought to be a potent antiandrogen, but subsequent research found that it actually possesses dose-dependent androgenic activity, albeit with lower efficacy than dihydrotestosterone (DHT). The drug is an N-substituted arylthiohydantoin and was derived from the first-generation nonsteroidal antiandrogen (NSAA) nilutamide. The second-generation NSAAs enzalutamide, RD-162, and apalutamide were derived from RU-59063.
RU-59063 has high affinity for the human androgen receptor (AR) (Ki = 2.2 nM; Ka = 5.4 nM) and 1,000-fold selectivity for the AR over other nuclear steroid hormone receptors, including the , , , and . It shows 3- and 8-fold higher affinity than testosterone for the rat and human AR, respectively, and up to 100-fold higher affinity for the rat AR than the first-generation NSAAs flutamide, nilutamide, and bicalutamide. It also has slightly higher affinity for the AR than DHT and nearly equal affinity to that of the very-high-affinity AR ligand metribolone (R-1881). In addition, RU-59063, unlike testosterone and DHT, shows no specific binding to human plasma.
See also
Cyanonilutamide
RU-58642
RU-58841
References
External links
Sarms & Bodybuilding
MK 677 Sarm For Research
MK 677 25mg
MK-677 Dosage, Results, Bodybuilding, Reviews, Cycle and Benefits
Abandoned drugs
Primary alcohols
Imidazolidines
Ketones
Nitriles
Selective androgen receptor modulators
Thioureas
Trifluoromethyl compounds
Benzonitriles | RU-59063 | [
"Chemistry"
] | 414 | [
"Ketones",
"Functional groups",
"Drug safety",
"Nitriles",
"Abandoned drugs"
] |
56,054,765 | https://en.wikipedia.org/wiki/Sigma%20electron%20donor-acceptor | The sEDA parameter (sigma electron donor-acceptor) is a sigma-electron substituent effect scale, described also as inductive and electronegativity related effect. There is also a complementary scale - pEDA. The more positive is the value of sEDA the more sigma-electron donating is a substituent. The more negative sEDA, the more sigma-electron withdrawing is the substituent (see the table below).
The sEDA parameter for a given substituent is calculated by means of quantum chemistry methods. The model molecule is the monosubstituted benzene. First the geometry should be optimized at a suitable model of theory, then the natural population analysis within the framework of Natural Bond Orbital theory is performed. The molecule have to be oriented in such a way that the aromatic benzene ring lays in the xy plane and is perpendicular to the z-axis. Then, the 2s, 2px and 2py orbital occupations of ring carbon atoms are summed up to give the total sigma system occupation. From this value the sum of sigma-occupation for unsubstituted benzene is subtracted resulting in original sEDA parameter. For sigma-electron donating substituents like -Li, -BH2, -SiH3, the sEDA parameter is positive, and for sigma-electron withdrawing substituents like -F, -OH, -NH2, -NO2, -COOH the sEDA is negative.
The sEDA scale was invented by Wojciech P. Oziminski and Jan Cz. Dobrowolski and the details are available in the original paper.
The sEDA scale linearly correlates with experimental substituent constants like Taft-Topsom σR parameter.
For easy calculation of sEDA the free of charge for academic purposes written in Tcl program with graphical user interface AromaTcl is available.
Sums of sigma-electron occupations and sEDA parameter for substituents of various character are gathered in the following table:
References
Organic chemistry
Quantum chemistry
Chemical bond properties | Sigma electron donor-acceptor | [
"Physics",
"Chemistry"
] | 437 | [
"Chemical bond properties",
"Quantum chemistry",
"Quantum mechanics",
"Theoretical chemistry",
" molecular",
"nan",
"Atomic",
" and optical physics"
] |
56,054,874 | https://en.wikipedia.org/wiki/Static%20synchronous%20series%20compensator | A static synchronous series compensator (SSSC) is a type of flexible AC transmission system which consists of a solid-state voltage source inverter coupled with a transformer that is connected in series with a transmission line. This device can inject an almost sinusoidal voltage in series with the line. This injected voltage could be considered as an inductive or capacitive reactance, which is connected in series with the transmission line. This feature can provide controllable voltage compensation. In addition, SSSC is able to reverse the power flow by injecting a sufficiently large series reactive compensating voltage.
The SSSC consists of a voltage source converter (VSC) connected in series with the transmission line through a transformer. The VSC, a power electronic device, converts direct current (DC) power into alternating current (AC) power, enabling the injection of the desired voltage. By controlling the magnitude and phase angle of this injected voltage, the SSSC can effectively modify the line's impedance.
One of the primary functions of the SSSC is to improve power flow control. By adjusting the line impedance, the SSSC can regulate the amount of power flowing through a specific transmission line. This is particularly useful for balancing power flows between different regions of a power system or for optimizing the utilization of existing transmission infrastructure.
Furthermore, the SSSC can enhance the stability of the power system by damping power oscillations. Power oscillations can occur due to disturbances such as sudden load changes or faults. The SSSC can quickly respond to these disturbances by injecting appropriate voltages, thereby stabilizing the system and preventing cascading failures.
In addition to power flow control and stability enhancement, the SSSC can also be used to improve voltage profile and mitigate voltage fluctuations. By injecting reactive power, the SSSC can regulate the voltage levels at various points in the power system, ensuring that they remain within acceptable limits. This is particularly important for maintaining the quality of power supply to consumers.
See also
Active power filter
Static synchronous compensator (STATCOM), a similar shunt-connected device
Unified power flow controller, a combination of SSSC and STATCOM
Dynamic voltage restoration
References
Electric power transmission
Power engineering
Power electronics | Static synchronous series compensator | [
"Engineering"
] | 475 | [
"Energy engineering",
"Electronic engineering",
"Power engineering",
"Electrical engineering",
"Power electronics"
] |
56,056,488 | https://en.wikipedia.org/wiki/Brevifollis | Brevifollis is a Gram-negative genus of bacteria from the family of Verrucomicrobiaceae with one known species (Brevifollis gellanilyticus).
See also
List of bacterial orders
List of bacteria genera
References
Verrucomicrobiota
Monotypic bacteria genera
Bacteria genera | Brevifollis | [
"Biology"
] | 66 | [
"Bacteria stubs",
"Bacteria"
] |
56,056,495 | https://en.wikipedia.org/wiki/NGC%20506 | NGC 506 is a star in the constellation Pisces. It was discovered on 7 November 1874 by Lawrence Parsons, the 4th Earl of Rosse.
Observation history
Lawrence discovered the object during his last observation of the NGC 499 Group. Though he noted no description, he gave a micrometric measure setting the object's position relative to a different nearby star. There is no object at this position, but the NGC position is corrected further southeast which leads to the assumption that John Louis Emil Dreyer, creator of the New General Catalogue, had additional information when he catalogued the star. In the catalogue, the object is described as "very faint, very small, southwest of NGC 507".
See also
Star
List of NGC objects (1–1000)
Pisces (constellation)
References
External links
SEDS
Pisces (constellation)
0506
Astronomical objects discovered in 1874
Discoveries by Lawrence Parsons | NGC 506 | [
"Astronomy"
] | 183 | [
"Pisces (constellation)",
"Constellations"
] |
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