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44,280,482 | https://en.wikipedia.org/wiki/Five%20Years | Five Years may refer to:
Music
Albums
Five Years (1969–1973), a 2015 compilation album by David Bowie
Five Years: Singles, a 2001 compilation album by Takako Matsu
5 Years (album), a 2010 album by Kaela Kimura
Songs
"Five Years" (David Bowie song), a song by David Bowie from the 1972 album Ziggy Stardust
"5 Years" (Björk song), a song by Björk from the 1997 album Homogenic
"Five Years", a song by Bo Burnham from the 2022 album The Inside Outtakes
Other
Five Years (book), a 1966 autobiographical collection of American social critic Paul Goodman's notebooks
Five Years, a 2019 series by Terry Moore
See also
"Five Long Years", a 1952 song by blues vocalist/pianist Eddie Boyd
Five-year plan (disambiguation)
Lustrum, a term for a five-year period in Ancient Rome.
Units of time | Five Years | [
"Physics",
"Mathematics"
] | 197 | [
"Physical quantities",
"Time",
"Units of time",
"Quantity",
"Spacetime",
"Units of measurement"
] |
44,280,556 | https://en.wikipedia.org/wiki/Ladislav%20Skula | Ladislav "Ladja" Skula (born June 30, 1937) is a Czech mathematician. His work spans across topology, algebraic number theory, and the theory of ordered sets. He has published over 80 papers and notable results on the Fermat quotient.
He obtained his Dr.Sc. degree from Charles University in Prague with a thesis on "obor Algebra a teorie čísel" (On Algebra and Number Theory). In 1991, he was appointed professor at the Masaryk University in Brno, where he is now emeritus professor.
Selected publications
External links
Skula's homepage at Masaryk University
Czech mathematicians
Number theorists
Living people
1937 births
Charles University alumni
Academic staff of Masaryk University | Ladislav Skula | [
"Mathematics"
] | 149 | [
"Number theorists",
"Number theory"
] |
44,281,046 | https://en.wikipedia.org/wiki/Error%20analysis%20%28mathematics%29 | In mathematics, error analysis is the study of kind and quantity of error, or uncertainty, that may be present in the solution to a problem. This issue is particularly prominent in applied areas such as numerical analysis and statistics.
Error analysis in numerical modeling
In numerical simulation or modeling of real systems, error analysis is concerned with the changes in the output of the model as the parameters to the model vary about a mean.
For instance, in a system modeled as a function of two variables Error analysis deals with the propagation of the numerical errors in and (around mean values and ) to error in (around a mean ).
In numerical analysis, error analysis comprises both forward error analysis and backward error analysis.
Forward error analysis
Forward error analysis involves the analysis of a function which is an approximation (usually a finite polynomial) to a function to determine the bounds on the error in the approximation; i.e., to find such that The evaluation of forward errors is desired in validated numerics.
Backward error analysis
Backward error analysis involves the analysis of the approximation function to determine the bounds on the parameters such that the result
Backward error analysis, the theory of which was developed and popularized by James H. Wilkinson, can be used to establish that an algorithm implementing a numerical function is numerically stable. The basic approach is to show that although the calculated result, due to roundoff errors, will not be exactly correct, it is the exact solution to a nearby problem with slightly perturbed input data. If the perturbation required is small, on the order of the uncertainty in the input data, then the results are in some sense as accurate as the data "deserves". The algorithm is then defined as backward stable. Stability is a measure of the sensitivity to rounding errors of a given numerical procedure; by contrast, the condition number of a function for a given problem indicates the inherent sensitivity of the function to small perturbations in its input and is independent of the implementation used to solve the problem.
Applications
Global positioning system
The analysis of errors computed using the global positioning system is important for understanding how GPS works, and for knowing what magnitude errors should be expected. The Global Positioning System makes corrections for receiver clock errors and other effects but there are still residual errors which are not corrected. The Global Positioning System (GPS) was created by the United States Department of Defense (DOD) in the 1970s. It has come to be widely used for navigation both by the U.S. military and the general public.
Molecular dynamics simulation
In molecular dynamics (MD) simulations, there are errors due to inadequate sampling of the phase space or infrequently occurring events, these lead to the statistical error due to random fluctuation in the measurements.
For a series of measurements of a fluctuating property , the mean value is:
When these measurements are independent, the variance of the mean is:
but in most MD simulations, there is correlation between quantity at different time, so the variance of the mean will be underestimated as the effective number of independent measurements is actually less than . In such situations we rewrite the variance as:
where is the autocorrelation function defined by
We can then use the auto correlation function to estimate the error bar. Luckily, we have a much simpler method based on block averaging.
Scientific data verification
Measurements generally have a small amount of error, and repeated measurements of the same item will generally result in slight differences in readings. These differences can be analyzed, and follow certain known mathematical and statistical properties. Should a set of data appear to be too faithful to the hypothesis, i.e., the amount of error that would normally be in such measurements does not appear, a conclusion can be drawn that the data may have been forged. Error analysis alone is typically not sufficient to prove that data have been falsified or fabricated, but it may provide the supporting evidence necessary to confirm suspicions of misconduct.
See also
Error analysis (linguistics)
Error bar
Errors and residuals in statistics
Propagation of uncertainty
Validated numerics
References
External links
All about error analysis.
Numerical analysis
Error | Error analysis (mathematics) | [
"Mathematics"
] | 821 | [
"Computational mathematics",
"Mathematical relations",
"Approximations",
"Numerical analysis"
] |
44,283,744 | https://en.wikipedia.org/wiki/Hyper-real%20religion | Hyper-real religion is a sociological term to describe a new consumer trend in acquiring and enacting religion. The term was first described in the book Religion and Popular Culture: A Hyper-Real Testament by Adam Possamai. The term is used to explore the intersection between postmodernity and religion. The idea has been expanded and critiqued by a number of academics since its creation.
Origins and usage
According to theories of postmodernization, the last half of the 20th century (often termed as the "postmodern era") saw consumerism, individualisation and choice come to the forefront of Western societies via capitalism. Thus religion as a part of this culture became increasingly commercial, individualised and democratized. People now have more choices in religion, they can often practice it in privacy and as they wish, outside of traditional institutional boundaries. Due to this change, the sociology of religion has become increasingly interested in the potential for typologization of the modes of non-institutional religion and the foundation of non-institutional religion in human nature.
It has become increasingly clear that the people leaving the structures and ceremonies of traditional religions are not instantly becoming non-religious in an atheistic sense. For example, some continue believing without belonging to a church, others turn to alternative spiritualities and others, as discussed by Possamai, turn to consumer based religions partly based on popular culture, what he calls "hyper-real religions." With hyper-real religion, elements from religions and popular culture are highly intertwined. They are post-modern expressions of religion, likely to be consumed and individualised, and thus have more relevance to the self than to a community and/or congregation. Thus in postmodern times, the relation between people and religion is very fluid; if modernity brought the disenchantment of the world, as Max Weber puts it, postmodernity is re-enchanting the world through a proliferation of 'subjective myths' (myths that are relevant to the self) and through the expansion of consumerism and the internet.
Possamai explains that the concept of hyper-real religions is derived from the work of Jean Baudrillard. Baudrillard put forward that we are living in an age of hyper-reality in which we are fascinated by simulations that lack a real world referent or simulacra. Possamai sees these simulations as part of the popular cultural milieu, in which "signs get their meanings from their relations with each other, rather than by reference to some independent reality or standard". With no way to "distinguish the real from the unreal", hyper-reality – the situation in which reality collapses – emerges. For example, we may refer to a person as being like Superman or Homer Simpson, rather than a real-life example of a hero or dunce, and theme parks represent movies or Disney creations rather than real life. The fictional character and world become more real for us than the real person or real world. Possamai, as Mark Geoffroy puts it, re-adapted Baudrillard's theory by applying it to religions that are engaged with these same simulated realities. In the most obvious examples, the Church of All Worlds draws its inspiration largely from Robert Heinlein’s Stranger in a Strange Land, Jediism draws on George Lucas' Star Wars mythology and Matrixism on The Matrix film franchise. Following these ideas Possamai defined hyper-real religions as:
...a simulacrum of a religion partly created out of popular culture which provides inspiration for believers/consumers at a metaphorical level.
Following critiques in the Handbook of Hyper-real Religions, Possamai modifies his original definition of hyper-real religions to:
A hyper-real religion is a simulacrum of a religion created out of, or in symbiosis with, commodified popular culture which provides inspiration at a metaphorical level and/or is a source of beliefs in everyday life.
Expansions and critiques of hyper-real religion as a concept
Eileen Barker suggests that the concept of hyper-real religions is ambiguous, however, she goes on, it is this ambiguity, this liminality, that gives it its greatest strength. Through this positioning it allows us to view novel religious developments and to view the effects of those developments on the older religions of the world. This allows the sharpening and refining of the tools of sociology of religion to take on contemporary developments in the religious field. Through Possamai's concepts, the differentiating effects of individualism, consumerism and democratisation of religion become salient.
Markus Davidsen argues that Possamai has identified a real class of religions but that the concept he uses to refer to them needs to be replaced. He argues that for Baudrillard, all religions are hyper-real in the sense that they ascribe reality to the socially constructed. Barker also suggests that if we were to take the methodologically agnostic stance of the social constructionists with regard to hyper-real religions, then we would insist that all religions should be evaluated as hyper-real. They all draw on realities without referent (see Cusack).
Similarly, Geoffroy argues that Baudrillard would not have been happy with Possamai’s "re-adaptation". For Baudrillard, religion had been out of the hyper-reality picture for a long time. Religion was an illusion of modernity that could not exist in hyper-reality, as our value systems exclude predestination of evil. Baudrillard was very cynical of the ability of popular culture to provide any sort of meaning: It is a form of alienation that cannot be a source of inspiration. Due to this, Geoffroy argues that it is unclear how hyper-real religions can be a re-adaptation of Baudrillard, since he does not acknowledge religion or the liberating effects of popular culture in his work. He suggests that what Possamai has done is to reinterpret Baudrillard. Geoffroy puts forward James A. Beckford's theories on "religion as a cultural resource", Forgues "symbolic activity" and Luckmann's "Invisible Religion" as alternative theories that could have been chosen to express Possamai's idea of hyper-real religions. However he concludes that it works as a useful and enlightening ‘re-interpretation’ of hyper-reality.
Davidsen concludes similarly, that this is a distinct class of religions but that we cannot meaningfully refer to them as hyper-real. He offers "fiction-based religion" as a more accurate term. Fiction-based religions draw their main inspiration from fictional narratives (e.g., Star Wars and The Lord of the Rings) which do not claim to refer to the actual world, but create a fictional world of their own. He draws a distinction between fiction (such as Star Wars), which does not claim to refer to the actual world, and history, including religious narratives, which does make such a claim. Third, he criticizes scholars like Cusack who argue that fandom, for instance, Star Trek fandom, is a form of religion. He draws an analytical distinction between religion and play, which he suggests makes it possible to distinguish between religious use of fiction (fiction-based religion) and playful engagement with fiction (fandom). Barker also questions whether there is a need to include these social manifestations as part of the concept of religion when perhaps they are examples of secular fiction, rather than religion, thus hyper-real religions blur the line between religion and non-religion, bringing more ideas and objects into the fold of religion.
Authors criticize the supposedly subjective nature of such consumer religions and Possamai’s use of the term "subjective myth". Roeland uses Possamai’s discussion of individualistic consumer religions to compare the subjectivity of such religious consumers with the realist construction of the evangelical Christian God. While the meaning of God and religion are subjective to Possamai’s subjective myth driven consumers, Dutch Christian evangelicals believe that their religion and God exist independently of our subjective desires and constructions. Thus, while subjectivism is present in evangelical circles, by the experiential orientation that they employ, it is employed to explore the real presence of God. The reality of God is experienced subjectively and attests to His reality. Thus, subjective perceptions of religious ideas do not necessarily negate their reality for practitioners and the authenticity of the experience can remain.
Likewise, Johan Roeland, Stef Aupers, Dick Houtman, Martijn de Koning, and Ineke Noomen criticize Possamai's idea of the New Age being constructed by the subjective myths of practitioners. They suggest that these portrayals show the New Age as spiritually and religiously incoherent. To the authors, this is an unfair portrayal which misses the fact that "self-spirituality" is a shared myth amongst New Age practitioners, one which goes beyond a personal story or subjective myth. They suggest, against Possamai, that the New Age is not a postmodern flight to the surface but a quest for solid foundations in a world ruined by complacent and shiftless religion. Anneke van Otterloo, Stef Aupers and Dick Houtman also argue that the New Age milieu is not as individualistic and rhizomatic as accounts such as Possamai's make it seem. They argue that this is due to New Age diffusion into Western culture by cultural and popular sources.
There are criticisms of Possamai's use of consumption. Paul Heelas critiques Possamai's view that the New Age is a consumer religion par excellence with a specific focus on individualistic preferences. He suggests that the practices of the New Age require a relational element that connects the Me to the We and thus are far less consumeristic and individualistic than Possamai argues. He argues that although Possamai denotes New Age as the consumer religion par excellence, he does little to discuss the actual processes that he thinks lead to this label. According to Heelas ‘Consumption’ and the ‘Consumer’ as words and processes remain undefined in Possamai's work and the work of many others in the field.
Helen Berger and Douglas Ezzy suggest that the witchcraft movements that they discuss have durability and integration that goes beyond the consumer religions discussed by Possamai. While Possamai sees witchcraft as consumerist in the same way as Matrixism, Berger and Ezzy argue that the stronger historical roots and variety of cultural resources available to the witchcraft community allow a higher level of durability and integration. Lastly, Geoffroy is critical of the market based nature of Possamai's idea, as he does not think that all metaphors can be sold as commodities.
Several authors critique Possamai's thinking about the authenticity of such religions. They argue that Possamai's concept suggests that these religions are less than ‘real’ in comparison to other religious forms. Tremlett describes this as the jargon of authenticity and cites Possamai, Cusack and Chidester as examples of this kind of framing of consumer religion. He suggests that Possamai's work is notable for rendering material relationships within capitalism in symbols and signs. Tremlett suggests that Possamai completely fails to acknowledge or apparently understand the importance of the term spectacle, which comes from Debord’s the Society of the Spectacle or the more general consequences that follow such a strategy of analysis. For example, according to Debord, the spectacle is not a collection of images, but a social relation among people, mediated by images. In other words, the apparent weightlessness of the sign and the image in postmodernity – of, in short, the spectacle – is precisely that: it is an appearance. To Tremlett such a mode of analysis will miss the real forces that lie behind these signs and images, regardless of what certain communities may have to say about them. In resonance, but in a different critical direction, while applying the concept of hyper-real religion to Hinduism, Scheifinger makes the argument that hyper-real religion is a Western construction. Given the generally hyper-real nature of the Hindu gods, his analysis raises the question of the universality of the concept, suggesting that it may only fit within a post-Christian environment where popular culture is fully commodified.
References
Sociology of religion
Religious studies
Postmodern religion
Hyperreality | Hyper-real religion | [
"Technology"
] | 2,600 | [
"Hyperreality",
"Science and technology studies"
] |
44,284,590 | https://en.wikipedia.org/wiki/Shazia%20Sadiq | Shazia Sadiq is an Australian computer scientist and academic. She is a Professor of Computer Science at the University of Queensland.
Background
Originally from Pakistan, Sadiq was one of a handful of women to undertake studies in a computer science program within Pakistan at Quaid-i-Azam University, Islamabad, Pakistan in 1980s, and wrote her first computer program in Fortran using punched cards.
She later received a NORAD scholarship to undertake a masters in computer science from the Asian Institute of Technology, Bangkok, Thailand. She then went on to do a PhD in Information Systems at the University of Queensland, Brisbane Australia, with Professor Maria Orlowska.
Since 2001, Sadiq has been based in the School of Information Technology and Electrical Engineering, at the University of Queensland. She conducts research and teaching in databases and information systems.
She serves as deputy chair on the Australian Academy of Science's National Committee on Information and Communication Sciences and formerly as vice president of the Asia Pacific Chapter of IQ International – the International Association of Information and Data Quality.
Education
Doctor of Philosophy (The University of Queensland, Brisbane, Australia, 2002)
Masters in Computer Science (Asian Institute of Technology, Bangkok, Thailand, 1993)
Masters in Computer Science (Quaid-i-Azam University, Islamabad, Pakistan, 1989)
Research and advocacy
Sadiq's research is focused on developing innovative solutions for Business Information Systems. She has published over 100 publications in prestigious journals and conferences such as SIGMOD, VLDBJ, TKDE, WWWJ, ISJ, CAiSE, ER, and BPM. She has also received several received grants. Her work on declarative modeling of complex and dynamic business requirements has been applied in the areas of business process management, and GRC (governance, risk and compliance) with approximately 1000 citations on the collective works. Sadiq is leading a group of researchers and students in the area of big data quality and integration with novel applications in transportation, social media and learning analytics. In addition to her work in research, Sadiq contributes to the professional community of data and information quality professionals as a board member of the Asia-Pacific Chapter of the International Association of Information and Data Quality and as convener of the Queensland Data Quality Roundtable.
Sadiq has also contributed to the enhancement of Information and Communications Technology (ICT) education for the last fifteen years. She has devoted considerable energy towards raising awareness of the importance of ICT skills for a number of disciplines, while ensuring that ICT students are equipped with the knowledge and confidence to tackle the rising challenges of a constantly evolving ICT landscape and a data driven society. Her teaching methods have been recognized through publications in leading conferences and journals, leadership roles at national and international ICT educational forums, and through University awards for teaching excellence.
Sadiq is an active supporter of initiatives toward improving female participation in ICT. She developed an interactive workshop series, which has been delivered to over a thousand high school students since 2006. The initiative aims to promote interest in ICT-related study and professional pursuits, especially for female students. The primary reason behind the design of the workshops is to demonstrate computing principles and techniques by masking them in various socially relevant applications such as health, forensics, genetics, fashion, movie making, game design, environment modeling, etc. Sadiq also gives role model talks; and participates in various girls in ICT events, such as Girls Into Doing Great Information Technology Society (GIDGITS) and “Technology Takes You Anywhere”.
Awards
Women in Technology Award for InfoTech Research 2012
The University of Queensland Award for Teaching Excellence 2012
Fellow of the Australian Academy of Technology and Engineering 2020
External links
Professor Shazia Sadiq, Australian Academy of Science
References
Australian women computer scientists
Living people
Year of birth missing (living people)
Australian computer scientists
Information systems researchers
University of Queensland alumni
Pakistani emigrants to Australia
Australian academics of Pakistani descent
Asian Institute of Technology alumni
Quaid-i-Azam University alumni
Academic staff of the University of Queensland | Shazia Sadiq | [
"Technology"
] | 801 | [
"Information systems",
"Information systems researchers"
] |
67,182,867 | https://en.wikipedia.org/wiki/Directional%20component%20analysis | Directional component analysis (DCA) is a statistical method used in climate science for identifying representative patterns of variability in space-time data-sets such as historical climate observations, weather prediction ensembles or climate ensembles.
The first DCA pattern is a pattern of weather or climate variability that is both likely to occur (measured using likelihood) and has a large impact (for a specified linear impact function, and given certain mathematical conditions: see below).
The first DCA pattern contrasts with the first PCA pattern, which is likely to occur, but may not have a large impact, and with a pattern derived from the gradient of the impact function, which has a large impact, but may not be likely to occur.
DCA differs from other pattern identification methods used in climate research, such as EOFs, rotated EOFs and extended EOFs in that it takes into account an external vector, the gradient of the impact.
DCA provides a way to reduce large ensembles from weather forecasts or climate models to just two patterns.
The first pattern is the ensemble mean, and the second pattern is the DCA pattern, which represents variability around the ensemble mean in a way that takes impact into account.
DCA contrasts with other methods that have been proposed for the reduction of ensembles in that it takes impact into account in addition to the structure of the ensemble.
Overview
Inputs
DCA is calculated from two inputs:
a multivariate dataset of weather or climate data, such as historical climate observations, or a weather or climate ensemble
a linear impact function. The linear impact function is a function which defines a level of impact for every spatial pattern in the weather or climate data as a weighted sum of the values at different locations in the spatial pattern. An example is the mean value across the spatial pattern. The linear impact function can be generated as the first term in the multivariate Taylor series of a non-linear impact function.
Formula
Consider a space-time data set , containing individual spatial pattern vectors , where the individual patterns are each considered as single samples from a multivariate normal distribution with mean zero and covariance matrix .
We define a linear impact function of a spatial pattern as , where is a vector of spatial weights.
The first DCA pattern is given in terms the covariance matrix and the weights by the proportional expression
.
The pattern can then be normalized to any length as required.
Properties
If the weather or climate data is elliptically distributed (e.g., is distributed as a multivariate normal distribution or a multivariate t-distribution) then the first DCA pattern (DCA1) is defined as the spatial pattern with the following mathematical properties:
DCA1 maximises probability density for a given value of impact
DCA1 maximises impact for a given value of probability density
DCA1 maximises the product of impact and probability density
DCA1 is the conditional expectation, conditional on exceeding a certain level of impact
DCA1 is the impact-weighted ensemble mean
Any modification of DCA1 will lead to a pattern that is either less extreme, or has a lower probability density.
Rainfall Example
For instance, in a rainfall anomaly dataset, using an impact metric defined as the total rainfall anomaly, the first DCA pattern is the spatial pattern that has the highest probability density for a given total rainfall anomaly. If the given total rainfall anomaly is chosen to have a large value, then this pattern combines being extreme in terms of the metric (i.e., representing large amounts of total rainfall) with being likely in terms of the pattern, and so is well suited as a representative extreme pattern.
Comparison with PCA
The main differences between Principal component analysis (PCA) and DCA are
PCA is a function of just the covariance matrix, and the first PCA pattern is defined so as to maximise explained variance
DCA is a function of the covariance matrix and a vector direction (the gradient of the impact function), and the first DCA pattern is defined so as to maximise probability density for a given value of the impact metric
As a result, for unit vector spatial patterns:
The first PCA spatial pattern always corresponds to a higher explained variance, but has a lower value of the impact metric (e.g., the total rainfall anomaly), except in degenerate cases
The first DCA spatial pattern always corresponds to a higher value of the impact metric, but has a lower value of the explained variance, except in degenerate cases
The degenerate cases occur when the PCA and DCA patterns are equal.
Also, given the first PCA pattern, the DCA pattern can be scaled so that:
The scaled DCA pattern has the same probability density as the first PCA pattern, but higher impact, or
The scaled DCA pattern has the same impact as the first PCA pattern, but higher probability density.
Two Dimensional Example
Source:
Figure 1 gives an example, which can be understood as follows:
The two axes represent anomalies of annual mean rainfall at two locations, with the highest total rainfall anomaly values towards the top right corner of the diagram
The joint variability of the rainfall anomalies at the two locations is assumed to follow a bivariate normal distribution
The ellipse shows a single contour of probability density from this bivariate normal, with higher values inside the ellipse
The red dot at the centre of the ellipse shows zero rainfall anomalies at both locations
The blue parallel-line arrow shows the principal axis of the ellipse, which is also the first PCA spatial pattern vector
In this case, the PCA pattern is scaled so that it touches the ellipse
The diagonal straight line shows a line of constant positive total rainfall anomaly, assumed to be at some fairly extreme level
The red dotted-line arrow shows the first DCA pattern, which points towards the point at which the diagonal line is tangent to the ellipse
In this case, the DCA pattern is scaled so that it touches the ellipse
From this diagram, the DCA pattern can be seen to possess the following properties:
Of all the points on the diagonal line, it is the one with the highest probability density
Of all the points on the ellipse, it is the one with the highest total rainfall anomaly
It has the same probability density as the PCA pattern, but represents higher total rainfall (i.e., points further towards the top right hand corner of the diagram)
Any change of the DCA pattern will reduce either the probability density (if it moves out of the ellipse) or reduce the total rainfall anomaly (if it moves along or into the ellipse)
In this case the total rainfall anomaly of the PCA pattern is quite small, because of anticorrelations between the rainfall anomalies at the two locations. As a result, the first PCA pattern is not a good representative example of a pattern with large total rainfall anomaly, while the first DCA pattern is.
In dimensions the ellipse becomes an ellipsoid, the diagonal line becomes an dimensional plane, and the PCA and DCA patterns are vectors in dimensions.
Applications
Application to Climate Variability
DCA has been applied to the CRU data-set of historical rainfall variability in order to understand the most likely patterns of rainfall extremes in the US and China.
Application to Ensemble Weather Forecasts
DCA has been applied to ECMWF medium-range weather forecast ensembles in order to identify the most likely patterns of extreme temperatures in the ensemble forecast.
Application to Ensemble Climate Model Projections
DCA has been applied to ensemble climate model projections in order to identify the most likely patterns of extreme future rainfall.
Derivation of the First DCA Pattern
Source:
Consider a space-time data-set , containing individual spatial pattern vectors , where the individual patterns are each considered as single samples from a multivariate normal distribution with mean zero and covariance matrix .
As a function of , the log probability density is proportional to .
We define a linear impact function of a spatial pattern as , where is a vector of spatial weights.
We then seek to find the spatial pattern that maximises the probability density for a given value of the linear impact function. This is equivalent to finding the spatial pattern that maximises the log probability density for a given value of the linear impact function, which is slightly easier to solve.
This is a constrained maximisation problem, and can be solved using the method of Lagrange multipliers.
The Lagrangian function is given by
Differentiating by and setting to zero gives the solution
Normalising so that is unit vector gives
This is the first DCA pattern.
Subsequent patterns can be derived which are orthogonal to the first, to form an orthonormal set and a method for matrix factorisation.
References
Climate and weather statistics
Numerical climate and weather models
Data analysis
Multivariate statistics
Climate | Directional component analysis | [
"Physics"
] | 1,794 | [
"Weather",
"Physical phenomena",
"Climate and weather statistics"
] |
67,184,106 | https://en.wikipedia.org/wiki/Association%20for%20Women%20in%20Mathematics%20Newsletter | Association for Women in Mathematics Newsletter is the membership journal of the Association for Women in Mathematics (AWM) and is published bimonthly. The inaugural issue appeared in May 1971, a few months after the AWM began. The first editor was Mary W. Gray, who was also the first "chairman" of the AWM. Gray was succeeded as editor by Alice T. Schafer, who also took over as president. Schafer edited a few issues and Judith Roitman succeeded her; Roitman later became the fourth AWM president. In 1977, Anne Leggett was appointed editor, a position which she retains to this day.
The AWM Newsletter is sent, by request, to all regular members of the AWM. It is currently an open access journal and all issues are available at its website. As described in "A Brief History of the Association for Women in Mathematics: The President's Perspectives," by third AWM president Lenore Blum:
Each issue contains the "President's Report," announcements of prizes and awards given to women, notices of upcoming meetings and workshops, several columns (Book Review, Education, Media and others), as well as "In Memoriam" articles. There is an archive of all past issues of the AWM Newsletter available as pdf files. Associate editor Sarah J. Greenwald created a searchable database, with the help of the migration specialist at Appalachian State University.
References
External links
Mathematics journals
English-language journals
Bimonthly journals
Publications established in 1971
Mathematics magazines
1971 establishments in the United States
Women in mathematics | Association for Women in Mathematics Newsletter | [
"Technology"
] | 321 | [
"Women in science and technology",
"Women in mathematics"
] |
67,184,342 | https://en.wikipedia.org/wiki/Non-numerical%20words%20for%20quantities | The English language has a number of words that denote specific or approximate quantities that are themselves not numbers. Along with numerals, and special-purpose words like some, any, much, more, every, and all, they are quantifiers. Quantifiers are a kind of determiner and occur in many constructions with other determiners, like articles: e.g., two dozen or more than a score. Scientific non-numerical quantities are represented as SI units.
List of non-numerical quantities
References
English language
Numbers | Non-numerical words for quantities | [
"Mathematics"
] | 111 | [
"Arithmetic",
"Mathematical objects",
"Numbers"
] |
67,185,372 | https://en.wikipedia.org/wiki/CNEOS%202014-01-08 | CNEOS 2014-01-08, also known as Interstellar meteor 1 (IM1), was a meteor that impacted Earth on 8 January 2014 near the northeast coast of Papua New Guinea. It was claimed to be an interstellar object in a 2019 preprint by astronomers Amir Siraj and Avi Loeb, and this was published in 2022. This was supported by the U.S. Space Command in 2022 based on the object's velocity relative to the Sun. NASA and Other astronomers doubt this, and still other experts found Earth-related explanations for the purported meteorite impact instead.
Discovery and putative confirmation
According to the researchers, the meteor originated from an unbound hyperbolic orbit with a confidence of 99.999%. The interstellar candidate was found in data from the Center for Near-Earth Object Studies. The estimated speed of the meteor, around , was likely produced in the innermost cores of another stellar system. A 2019 study by Jorge I. Zuluaga published as a research note by the American Astronomical Society concluded that even if the direction were completely unknown, the probability that CNEOS 2014-01-08 was hyperbolic would still be 48%.
Confirmation is stymied because information quantifying the accuracy of the U.S. government's data is not publicly available. In 2022, the United States Space Command divulged that data on the meteor velocity is "sufficiently accurate to indicate an interstellar trajectory."
Further related studies were reported on 1 September 2023.
Search for fragments
Amir Siraj, one of the authors who reported the finding of the purported interstellar meteorite, noted, "We are currently investigating whether a mission to the bottom of the Pacific Ocean off the coast of Manus Island in the hopes of finding fragments of the 2014 meteor could be fruitful or even possible." Later, in a preprint (as well as in interviews) they described the expedition plan by The Galileo Project to retrieve small fragments of the meteor which, according to Loeb, "appears to be rare both in composition and in speed" and is not ruled out to be "extraterrestrial equipment," using a magnetic sled on the seafloor of the impact region deployed using a long line winch. Siraj noted that "The alternative way to study an interstellar object at close range is by launching a space mission to a future object passing through the Earth's neighborhood" which is thought to be much more expensive than the project's planned budget of $1.6 million. In the study, the astronomers write:
Interestingly, CNEOS 2014-01-08, with a ram pressure of 194 MPa at peak brightness, has the highest material strength of all 273 bolides. The second highest tensile strength is smaller by more than a factor of 2, namely 81 MPa for the 2017-12-15 13:14:37 bolide. The third highest tensile strength, 75 MPa, belongs to the 2017-03-09 04:16:37 bolide, which we identified as a possible interstellar meteor candidate (Siraj & Loeb 2019c). Of course, this result does not imply that the first interstellar meteor was artificially made by a technological civilization and not natural in origin (Loeb 2021). Iron meteorites make about a twentieth of all space rocks arriving on Earth.In a September 2022 blog post Loeb announced The Galileo Project expedition to search for fragments has been fully funded.
In November 2022, a paper was published, claiming the anomalous properties (including its high strength and strongly hyperbolic trajectory) of CNEOS-2014-01-08 are better described as measurement error rather than genuine parameters. If true, successful retrieval of any meteoroid fragments is highly unlikely.
In July 2023, Amir Siraj and Avi Loeb reported finding metallic fragments that they believed to be from IM1 whose isotopic ratios indicated it was older than the solar system. Other astronomers doubt the meteor was interstellar, and other experts criticized Siraj and Loeb's method of determining where the meteor might have landed on Earth, showing that seismic data they used was not a result of an impact, but of nearby truck traffic.
See also
ʻOumuamua
2I/Borisov
References
External links
Ask Ethan: Did we recover alien technology from the bottom of the ocean? (14 July 2023)
Meteoritical Society
Earth Impact Database
Every Recorded Meteorite Impact on Earth from Tableau Software
Interstellar objects
Meteoroids
Solar System | CNEOS 2014-01-08 | [
"Astronomy"
] | 932 | [
"Interstellar objects",
"Astronomical objects",
"Outer space",
"Solar System"
] |
67,188,634 | https://en.wikipedia.org/wiki/Regius%20Professor%20of%20Astronomy%20%28Edinburgh%29 | The Regius Chair of Astronomy is one of eight Regius Professorships at the University of Edinburgh, and was founded in 1785. Regius Professorships are those that have in the past been established by the British Crown, and are still formally appointed by the current monarch, although they are advertised and recruited by the relevant university following the normal processes for appointing a professorship.
Relationship with the Astronomer Royal for Scotland
The Regius Chair of Astronomy in Edinburgh is unusual because of its relationship with the position of the Astronomer Royal for Scotland, and the Royal Observatory Edinburgh (ROE). Between 1834 and 1990, the Regius Professor at the University, the Astronomer Royal, and the Director of the Royal Observatory were all the same person. This is no longer true however, as explained under "New Structure" below.
Early history
Astronomy was originally taught in Edinburgh by the Chairs of Mathematics and of Natural Philosophy.
A Chair of Practical Astronomy was established in 1785 by a Royal Warrant signed by George III. The first holder was Robert Blair, who held the position until his death in 1828. However, he was never provided with an observatory or any instruments, and refused to do any teaching, seeing the position as a sinecure.
At that time, the Royal Commission was reviewing Scottish Universities and recommended that the chair should not be filled 'until a suitable observatory... could be established'
Meanwhile, outside the University, the Edinburgh Astronomical Institution, a club of private individuals, had succeeded in building an observatory on Calton Hill in a new building designed by William Playfair. In 1822 the Institution presented a loyal address to George IV, resulting in the observatory being granted the title of Royal Observatory. After considerable delay and negotiation, in 1834 Thomas Henderson was appointed as both the first Astronomer Royal for Scotland and the second Regius Professor. He remained in both positions until he died in 1844. Thomas Henderson's main claim to fame is being, along with Friedrich Bessel, the first astronomer to measure the parallax of a star, and hence a reliable stellar distance. He made his measurements at the Cape of Good Hope and reduced the data after taking up his position in Edinburgh.
In 1846 Charles Piazzi Smyth became Regius Professor and Astronomer Royal, and held both positions until he retired in 1888. He was the first Regius Professor to actually provide lectures in Astronomy, sixty five years after the founding of the chair.
Piazzi Smyth had a long and full career, including the establishment of a public time service via the Time Ball and the One O'Clock Gun, the exploration of the idea of mountain top astronomy, the investigation of the spectra of the Sun, the Zodiac and the Aurora, and innovative developments in photography.
Later in his life he became obsessed with mystical interpretations of the Pyramids.
The new observatory
Following the retirement of Piazzi Smyth, both the future of the Royal Observatory and the Regius Professorship were once again thrown into uncertainty by a Royal Commission on Scottish Universities, until the generous gift of Lord Lindsay led to the creation of a new Royal Observatory building on Blackford Hill (see for extensive detail), and Ralph Copeland was appointed as fourth Regius Professor and third Astronomer Royal. Copeland was well known for spectroscopic observations of planets, comets, and nebulae, and was the first person to observe Helium outside the Sun. He also carried out extensive travel, both to observe transits of Venus, and to continue Piazzi Smyth's researches into mountain top astronomy.
Copeland died in 1905 and was replaced both as Regius Professor and as Astronomer Royal by Frank Dyson. He was the first Regius Professor whose title was simply "Chair of Astronomy" rather than "Chair of Practical Astronomy". He investigated the spectrum of the solar corona and chromosphere. In 1910 he left to become Director of the Royal Greenwich Observatory and (English) Astronomer Royal - the only astronomer to have held both Astronomer Royal positions. He later became famous for organising eclipse expeditions which helped to proved Einstein's General Relativity Theory, and for instigating the transmission of the "pips" from the Greenwich Observatory to the BBC.
In 1910 Dyson was replaced by Ralph Sampson. Before coming to Edinburgh Sampson was well known for pioneering work on the colour temperature of stars, and a theory of the motions of the Galilean satellites. After his appointment, his work took a very practical turn, aiming at producing a more accurate time service, improving the optical performance of telescopes, and developing a recording microphotometer and techniques for performing spectrophotometry of stars. He also led the construction of 36inch telescope which still sits in the East Tower of the ROE. Sampson retired in 1937, to be replaced by W.M.H. Greaves in 1938. Greaves kept the national time service going the war, and led extensive work on determining the temperatures of stars, and the physical properties of their atmospheres, using spectrophotometry, as well as studies of the effect of sunspots in terrestrial magnetism. He died suddenly in 1955, and was replaced as both Regius Professor and Astronomer Royal by Hermann Bruck.
Modern developments
During the 1960s and 1970s, the ROE underwent considerable expansion, so that technical and scientific contributions are properly seen as due to a whole community. Nonetheless, it is possible to discern clear themes in the leadership of successive astronomers.
Hermann Bruck was the most important historical figure for Edinburgh astronomy, at least in leadership terms. When he arrived in 1957 the observatory had six scientific staff. By the time he retired in 1975, there over a hundred, and the observatory was established as a major international centre. There were three main themes to his leadership. The first, together with his wife Mary Bruck (nee Conway) was the creation of the first full Astrophysics degree, and the expansion of first year astronomy teaching to large classes of students from many disciplines. The second theme was automation - both computerised data reduction, and the creation of automated measuring machines, which led to a sequence of machines which scanned and digitised photographic plates - GALAXY, COSMOS, and SuperCOSMOS. The third theme was the development of mountaintop overseas observatories, fulfilling the dreams of Piazzi-Smyth. This work began with the creation of a station at Monte Porzio in Italy, followed by the design of a Northern Hemisphere Observatory in La Palma (which was then implemented by the Royal Greenwich Observatory), the building and operation of the UK Schmidt Telescope in Australia, and finally the building and operation of the infra-red specialised UK Infrared Telescope (UKIRT) in Hawaii. Bruck retired in 1975.
The next holder of both the Regius Professorship and the Astronomer Royal position was Vincent Reddish, who had been at ROE since the 1960s, and in fact was to a large extent responsible for many of the advances in the Bruck era - automation, systematic sky surveys, and the creation of the UK Schmidt Telescope and UKIRT. He resigned in 1978 and concentrated on his controversial private researches into dowsing.
Malcolm Longair was appointed to the joint position in 1980, and continued the trends started by Bruck and Reddish of making the Royal Observatory Edinburgh a centre of astronomical technology and sky survey work. Under Longair's leadership the ROE created a radical new facility, the James Clerk Maxwell Telescope (JCMT), and built a series of ground breaking instruments for both ground-based and space-based instruments. University leadership in Astronomy was however largely delegated to Mary Bruck and Peter Brand, under whom the Department of Astronomy merged with the Department of Physics, and was re-named the Institute for Astronomy. Longair resigned in 1990, during a difficult period of political discussion over the structure of British Astronomy, and moved to the Cavendish Laboratory in Cambridge.
New Structure
Developments since 1994 here.
List of holders of the chair
Here "ARn" refers to the holder also being the n'th Astronomer Royal for Scotland. In al those cases, the date of holding the Astronomer Royal position are the same as for holding the Regius chair.
Robert Blair 1785-1828
Thomas Henderson 1834-1844 (AR1)
Charles Piazzi Smyth 1846-188 (AR2)
Ralph Copeland 1889-1905 (AR3)
Frank Watson Dyson 1905-1910 (AR4)
Ralph Allen Sampson 1910-1937 (AR5)
Michael Greaves 1938 (AR6)
Hermann Bruck 1957 (AR7)
Vincent Reddish 1975 (AR8)
Malcolm Longair 1980 (AR9)
Andy Lawrence 1994-
References
Astronomy
Astronomy, Edinburgh
Astronomy | Regius Professor of Astronomy (Edinburgh) | [
"Astronomy"
] | 1,715 | [
"nan"
] |
67,189,094 | https://en.wikipedia.org/wiki/Celltick%20Technologies | Celltick Technologies is a US-based telecom technology provider specializing in public warning systems, cell broadcasting and mass notification platforms. The company is also known for creating software applications which are used by mobile carriers, OEM and governmental organizations.
History
Ronen Daniel co-founded Celltick technologies in the year 2000. In 2005, the company raised $11 million from Amadeus Capital Partners and Jerusalem Venture Partners while in the verge of expanding on western Europe.
In pre-android era, during the year 2002, Celltick released its first product a software named as LiveScreen, for mobile operators which invited considerable media attentions in subsequent years. The aim was to deliver mobile contents and services directly to the handset of the consumers. Later on, the software was extended on symbian os, for the handsets manufactured by Nokia. The software had an applet embedded within the SIM card. LiveScreen is currently being used by multiple mobile operators worldwide to date including BSNL, Airtel, Tele2, Vodafone, Taiwan Mobile, Globe Telcom Philippines etc.
In 2013, Celltick released the Start interface for android based handsets, which was utilized by multiple mobile operators and device manufacturers reaching around 150 million installations. In 2019, the Start division was acquired by Taboola.
In January 2021, Frykhammar, former CFO and CEO of Ericsson joined Celltick as chairman of the board. Subsequently, Celltick is known for providing services to mobile operators and governments in Europe to meet the requirements of Article 110 in the legislation of the European Electronic Communications Code, mandating all member states to deploy a mobile public warning system by June 2022.
References
Mobile content
Emergency communication
Health care companies established in 2000
Mobile software distribution platforms
American companies established in 2000 | Celltick Technologies | [
"Technology"
] | 355 | [
"Mobile content",
"Mobile software distribution platforms"
] |
67,190,745 | https://en.wikipedia.org/wiki/Dieter%20B.%20Herrmann | Dieter Bernhard Herrmann (3 January 1939 – 25 November 2021) was a German historian of astronomy and author of numerous popular science books on astronomy. He was director of the Zeiss Major Planetarium in Berlin from 1987 to 2004. In his scientific work he dealt with the early development of astrophysics and the application of quantitative methods in the history of science.
Life and career
Born in Berlin, Germany, Herrmann studied physics at the Humboldt University of Berlin from 1957 to 1963. From 1963 to 1969, he was employed at the . In 1969, he obtained a doctorate (Dr. rer. nat.) at the Humboldt University on the topic The Emergence of Astronomical Journals in Germany, 1798–1821.
Herrmann was director of the Archenhold Observatory in Berlin-Alt-Treptow from 1 November 1976 to 30 September 2004, succeeding Diedrich Wattenberg. In 1986, he completed his habilitation (Dr. sc. phil.) and was appointed honorary professor. In 1987, he was the founding director of the associated Zeiss Major Planetarium in Berlin-Prenzlauer Berg. He also hosted the popular science programme "AHA" of Deutscher Fernsehfunk for 14 years, for which he was awarded the Golden Laurel of GDR Television three times.
Herrmann's work included extensive lecturing activities. He was the author of 45 books, 150 scientific and about 2,000 popular science publications, as well as the successful planetarium programmes "Phantastisches Weltall", "Sterne, Nebel, Feuerräder", "Als der Mond zum Schneider kam", "Die große Tour durch die Welt der Planeten" (premiere 1993).
Herrmann was a member of the International Astronomical Union, the European Astronomical Society, the , the , the Astronomische Gesellschaft and other scientific associations. He was a member of the Science Council of the Society for the Scientific Investigation of Parasciences as well as on the Scientific Advisory Board of the Journal of Anomalistics published by the .
From 2006 until January 2012, he was president of the Leibniz-Sozietät (since 2007 Leibniz-Sozietät der Wissenschaften zu Berlin). On 27 June 2012, he was elected to the board of Urania in Berlin. On 18 May 2012, Herrmann was appointed honorary member of the Gesellschaft Deutschsprachiger Planetarien.
From January 2010 to April 2015, Herrmann gave a monthly overview of the current starry sky in his video column "Herrmanns Himmelsblicke" on the website of the Märkische Oderzeitung. Since 26 September 2010, the star discovered on 11 January 2000 at the Volkssternwarte Drebach as a minor planet (103460) bears the name Dieterherrmann.
On 17 September 2019, Herrmann was awarded the prestigious of the Astronomische Gesellschaft "for decisively shaping the public perception of astronomy by presenting inherently new astronomical results to the public over several decades". He was a member of the advisory board of the Study Foundation of the Berlin House of Representatives and was elected a member of the board in 2020.
Personal life
From October 2004, Herrmann lived in Berlin as a freelance researcher and author. From 2008, he was married to the Berlin artist Sabine Heinz. Herrmann died at age 82 after a severe illness.
Publications
Herrmann's publications are held by the German National Library, including:
Geschichte der Astronomie von Herschel bis Hertzsprung. VEB Deutscher Verlag der Wissenschaften, Berlin, 1975, in English by the Cambridge University Press, Cambridge 1984; 3rd edition 1980, 4th edition under the title Geschichte der modernen Astronomie, Berlin 1984.
Kosmische Weiten, Geschichte der Entfernungsmessung im Weltall. Johann Ambrosius Barth, Leipzig 1977, 4th edition Cologne 1990.
Vom Schattenstab zum Riesenspiegel. 2000 Jahre Technik der Himmelsforschung. Verlag Neues Leben, Berlin 1978, 4th edition 1989.
Entdecker des Himmels. Urania-Verlag, Leipzig Jena Berlin 1978, 4th edition 1990, also in Russian in 1981 by "Mir" as well as Hungarian in 1981 by "Gondolat" Edition.
Besiedelt die Menschheit das Weltall? in: ( vol. 50) Urania-Verlag, Leipzig Jena Berlin 1981
Ejnar Hertzsprung. Pionier der Sternforschung. with 41 illustrations, Springer, Berlin-Heidelberg New York 1994, 241 pages, (pocket book edition 2012).
Sonne, Mond und Sterne. Franckh-Kosmos, Stuttgart 1995, 2nd edition: Kosmos, Stuttgart 2003.
Antimaterie: Auf der Suche nach der Gegenwelt. Beck, Munich 1998, and 4th, updated edition 2009.
Die Milchstraße. Das aktuelle Wissen über unsere Heimatgalaxie. Franckh-Kosmos, Stuttgart 2003, .
Astronomiegeschichte. Umfangreiche Sammlung von wissenschaftlichen Beiträgen zur Geschichte der Astronomie. Paetec, Frankfurt, 2004, .
Sterne der Traumzeit. Reiseminiaturen, Begegnungen mit der astronomischen Kultur der Länder Ägypten, Indien, Italien, Mexico, Frankreich und Australien. Duden Paetec, Frankfurt, 2005, .
Der Jugendbrockhaus Weltall und Raumfahrt. Mannheim 2007, .
Die große Kosmos Himmelskunde. Planeten, Sterne, Galaxien – moderne Astronomie ganz verständlich. Stuttgart 2007, .
Astronom in zwei Welten. Autobiographie. Mitteldeutscher Verlag, Halle 2008, .
Der Zyklop. Die Kulturgeschichte des Fernrohrs. Westermann-Braunschweig 2009, .
Sonne, Mond und Sterne. Curis Abenteuer im Weltall. In: Kon Te Xis. Arbeitsheft. 2009, No. 1; PDF).
"Ich bin mit jedem Lob einverstanden". Hanns Eisler im Gespräch 1960–1962. , Leipzig 2009, .
Urknall im Labor. Wie Teilchenbeschleuniger die Natur simulieren. Springer, Berlin 2010, .
Planeten, Sterne, Galaxien. Ein Streifzug durch das Weltall. Illustrations by Vitali Konstantinov. Gerstenberg-Verlag Hildesheim 2014, 2nd edition 2017, , also in Spanish at Liberalia Ediciones, Santiago de Chile 2017 and Chinese at Red Dot Wisdom Cultural Development, Beijing 2018.
Das Urknall-Experiment. Auf der Suche nach dem Anfang der Welt. Franckh-Kosmos Verlags-GmbH & Co. KG, Stuttgart 2014, .
Die Harmonie des Universums. Von der rätselhaften Schönheit der Naturgesetze. Franckh-Kosmos Verlags-GmbH & Co. KG, Stuttgart 2017, .
Himmelskunde. Eine Einführung in die Astronomie. Franckh-Kosmos Verlags-GmbH & Co. KG, Stuttgart 2018, .
Dieter B. Herrmann and Christian Gritzner (eds.): Beiträge zur Geschichte der Raumfahrt. Ausgewählte Vorträge der Raumfahrthistorischen Kolloquien 1986–2015. In: Abhandlungen der Leibniz-Sozietät der Wissenschaften, vol. 46. trafo Verlagsgruppe Dr. Wolfgang Weist, Wissenschaftsverlag, Berlin 2017,
, Dieter B. Herrmann, (eds.): 25 Jahre Leibniz-Sozietät der Wissenschaften zu Berlin. Reden der Präsidenten auf den Leibniz-Tagen 1993–2017. In: Abhandlungen der Leibniz-Sozietät der Wissenschaften, vol. 50. trafo Verlagsgruppe Dr. Wolfgang Weist, Wissenschaftsverlag, Berlin 2018,
Atlas astronomischer Traumorte: Entdeckungsreisen auf den Spuren der Sternkunde. Franckh-Kosmos Verlags, Stuttgart 2019,
Astronomie – Bildung – Philosophie. Ausgewählte Vorträge und Aufsätze 1995–2020. In: Abhandlungen der Leibniz-Sozietät der Wissenschaften, vol. 62, trafo-Verlagsgruppe, Wissenschaftsverlag Berlin, 2020, .
References
Further reading
Eckehard Rothenberg: Laudatio. In Eckehard Rothenberg, Dietmar Fürst (ed.): Wege der Erkenntnis. Festschrift für Dieter B. Herrmann zum 65. Geburtstag (Acta Historica Astronomiae. Vol. 21). Frankfurt, 2004, , .
Dieter B. Herrmann: Bibliographie wissenschaftlicher Veröffentlichungen. Edited by Dietmar Fürst. In Eckehard Rothenberg, Dietmar Fürst (ed.): Wege der Erkenntnis. Festschrift for Dieter B. Herrmann on the occasion of his 65th birthday (Acta Historica Astronomiae. vol. 21). Frankfurt, 2004, , .
Herrmann, Dieter B(ernhard). in (ed.): Deutsches Literatur-Lexikon. Das 20. Jahrhundert. Vol. 17 Henze – Hettwer. De Gruyter, 2011, Sp. 242ff.
: Laudatio Dieter B. Herrmann. In: Sitzungsberichte der Leibniz-Sozietät der Wissenschaften zu Berlin.'' 103/2009 (PDF 30 kB)
External links
1939 births
2021 deaths
20th-century German astronomers
21st-century German astronomers
Historians of astronomy
Humboldt University of Berlin alumni
Scientists from Berlin | Dieter B. Herrmann | [
"Astronomy"
] | 2,184 | [
"People associated with astronomy",
"Historians of astronomy",
"History of astronomy"
] |
67,190,786 | https://en.wikipedia.org/wiki/Austrian%20Centre%20for%20Electron%20Microscopy%20and%20Nanoanalysis | The Austrian Centre for Electron Microscopy and Nanoanalysis (short: FELMI-ZFE) is a cooperation between the Institute of Electron Microscopy and Nanoanalysis (FELMI) of the Graz University of Technology (TUG) and the Graz Centre of Electron Microscopy (ZFE), which is a member of Austrian Cooperative Research (ACR) and run by the non-profit association for the promotion of electron microscopy. It is located at the “Neue Technik Steyrergasse” campus in Graz.
The FELMI-ZFE is offering both research and services, to interested partners from academia and industry, using advanced electron microscopic methods for both structural and chemical characterization.
History
The acquisition process of the first electron microscope of the Graz University of Technology was started by a donation from industry in 1949. The next year a research group, headed by Fritz Grasenick, was established. Finally, the first electron microscope (“Übermikroskop UEM100” by Siemens & Halske) was bought in 1951 and the opening ceremony was attended by Ernst Ruska, Werner Glaser and Otto Wolf. Despite the Graz University of Technology providing rooms and infrastructure, from the very beginning supplementary income from services research provide for industry was necessary to help cover the high operating and investment cost. Due to the larger interest in measurements and the high utilization of the instrument, the group soon need to expand its personal and look to acquire need microscopes. In order to concentrate all funding sources the non-profit association for the promotion of electron microscopy (Verein zur Förderung der Elektronenmikroskopie und Feinstrukturforschung) was founded in 1959 under the direction of the governor of Styria Josef Krainer senior. The Graz Centre of Electron Microscopy (ZFE) was attached to this non-profit. The combined institutions grew over the years, where the combined role of the head of the university institute and the head of the ZFE in one person played a crucial role in the development of a tight interconnection between fundamental research and application. In 2011 the to this date most expansive and impressive acquisition was possible, a at that time worldwide unique STEM. With the ASTEM (Austrian Scanning Transmission Electron Microscope) magnification of more than one million became possible, this enables atomic resolution. In addition, with an investment volume of 4.5 Mio. Euro, the ASTEM was one of the larges scientific infrastructure investments in Austria.
Head of institute
Organizational structure, Research & Services
Approximately 50 people work at the FELMI-ZFE with the number varying somewhat due to dissertations and research projects. In addition roughly 300 scientist visit the FELMI-ZFE each year.
International collaboration
There are standing collaboration with approximately 30 research institutes and 140 companies. In addition, since the establishment of the ASTEM, the FELMI-ZFE is part of ESTEEM3 (Enabling Science and Technology through European Electron Microscopy), which is a network of 14 electron microscopy institutes in Europe.
Research & Services
Five groups work on four main topics of research:
Nanoanalytic of materials
Functional Nanostructuring
3D and in situ measurements
Polymers and biological materials
Instruments
Scanning electron microscopy (SEM)
Transmission electron microscopy (TEM)
Infrared- and Raman-microscopy (IR/Raman)
Focused-Ion-Beam-Microscopy (FIB)
Atomic forces microscopy (AFM)
X-ray diffraction (XRD)
Sample preparation
Teaching and Education
In the academic year 2019/2020 approximately 600 students visited lectures and lab exercises of the Institute of Electron Microscopy and Nanoanalysis. The courses offered are on the topics of fundamental physics, material analysis, electron microscopy and nano-manufacturing. In addition apprenticeships for both lab-technician and media technology are offered.
External links
Webpage of the FELMI-ZFE
References
Graz University of Technology
Electron microscopy | Austrian Centre for Electron Microscopy and Nanoanalysis | [
"Chemistry"
] | 789 | [
"Electron",
"Electron microscopy",
"Microscopy"
] |
67,191,437 | https://en.wikipedia.org/wiki/Sensel | Sensel is an electronics company based in Sunnyvale, California that builds touch input technologies . It was founded in 2013 by former Amazon engineers Ilya Rosenberg and Aaron Zarraga. Sensel's first product, the Morph, is a pressure sensitive input device for creative applications. In January 2021, it was announced that Sensel's touch technology would be incorporated in the touchpad for Lenovo’s ThinkPad X1 Titanium Yoga laptop.
History
Sensel co-founder and CEO Ilya Rosenberg met co-founder and CTO Aaron Zarraga while working at Amazon's Lab126. After leaving Amazon, the two founded Sensel in 2013.
Together, the pair invented a new type of force sensor that could be manufactured like a printed circuit board. Sensel used Kickstarter in 2015 to bring its first product, The Morph, to market. The campaign raised $442,648. The Morph began shipping to its Kickstarter backers in 2017, and became available for direct purchase later that year.
In 2019, Sensel began shipping its first new Morph Overlay since its Kickstarter campaign, the Buchla Thunder Overlay, which was created in partnership with synthesizer and MIDI controller manufacturer Buchla U.S.A.
In 2021, Sensel announced its new touchpad demonstration kit with touch, force, and haptic technologies. It was also announced that Sensel's touch technology would be included in the touchpad for Lenovo's ThinkPad X1 Titanium Yoga laptop.
In May 2022, Sensel announced that it has discontinued the Morph and would not bring it back into production. The possibility of some new product at some future unspecified time was suggested.
References
External links
Official Sensel website
Sensel Morph website
Music technology
Crowdfunded consumer goods
Computer companies of the United States
Computer hardware companies
Computer peripheral companies
Technology companies based in the San Francisco Bay Area
MIDI controllers | Sensel | [
"Technology"
] | 396 | [
"Computer hardware companies",
"Computers"
] |
67,192,104 | https://en.wikipedia.org/wiki/Year%20loss%20table | A year loss table (YLT) is a table that lists historical or simulated years, with financial losses for each year. YLTs are widely used in catastrophe modeling as a way to record and communicate historical or simulated losses from catastrophes. The use of lists of years with historical or simulated financial losses is discussed in many references on catastrophe modelling and disaster risk management, but it is only more recently that the term YLT has been standardized.
Overview
Year of interest
In a simulated YLT, each year of simulated loss is considered a possible loss outcome for a single year, defined as the year of interest, which is usually in the future. In insurance industry catastrophe modelling, the year of interest is often this year or next, due to the annual nature of many insurance contracts.
Events
Many YLTs are event based; that is, they are constructed from historical or simulated catastrophe events, each of which has an associated loss. Each event is allocated to one or more years in the YLT and there may be multiple events in a year. The events may have an associated frequency model, that specifies the distribution for the number of different types of events per year, and an associated severity distribution, that specifies the distribution of loss for each event.
Use in insurance
YLTs are widely used in the insurance industry, as they are a flexible way to store samples from a distribution of possible losses. Two properties make them particularly useful:
The number of events within a year can be distributed according to any probability distribution and is not restricted to the Poisson distribution
Two YLTs, each with an arbitrary number of years, can be combined, year by year, to create a new YLT with the same number of years
Examples of YLTs
YLTs are often stored in either long-form or short-form.
Long-form YLTs
In a long-form YLT, each row corresponds to a different loss-causing event. For each event, the YLT records the year, the event, the loss, and any other relevant information about the event.
In this example:
The Events IDs refer to a separate database that defines the characteristics of the events, known as an event loss table (ELT)
Year 1 contains two events: events 965 and 7, with losses of $100,000 and $1,000,000, giving a total loss in year 1 of $1,100,000
Year 2 only contains one event
Year 3 contains no events
Event 7 occurs (at least) twice, in years 1 and 100,000
Year 100,000 contains 3 events, with a total loss of $6,000,000
Short-form YLTs
In a short-form YLT, each row of the YLT corresponds to a different year. For each event, the YLT records the year, the loss, and any other relevant information about that year.
The same YLT above, condensed to a short form, would look like:
Frequency models
The most commonly used frequency model for the events in a YLT is the Poisson distribution with constant parameters. An alternative frequency model is the mixed Poisson distribution, which allows for the temporal and spatial clustering of events.
Stochastic parameter YLTs
When YLTs are generated from parametrized mathematical models, they may use the same parameter values in each year (fixed parameter YLTs), or different parameter values in each year (stochastic parameter YLTs).
As an example, the annual frequency of hurricanes hitting the United States might be modelled as a Poisson distribution with an estimated mean of 1.67 hurricanes per year. The estimation uncertainty around the estimate of the mean might considered to be a gamma distribution. In a fixed parameter YLT, the number of hurricanes every year would be simulated using a Poisson distribution with a mean of 1.67 hurricanes per year, and the distribution of estimation uncertainty would be ignored. In a stochastic parameter YLT, the number of hurricanes in each year would be simulated by first simulating the mean number of hurricanes for that year from the gamma distribution, and then simulating the number of hurricanes itself from a Poisson distribution with the simulated mean.
In the fixed parameter YLT the mean of the Poisson distribution used to model the frequency of hurricanes, by year, would be:
In the stochastic parameter YLT the mean of the Poisson distribution used to model the frequency of hurricanes, by year, might be:
Adjusting YLTs and WYLTs
It is often of interest to adjust YLTs, perform sensitivity tests, or make adjustments for climate change. Adjustments can be made in several different ways. If a YLT has been created by simulating from a list of events with given frequencies, then one simple way to adjust the YLT is to resimulate but with different frequencies. Resimulation with different frequencies can be made much more accurate by using the incremental simulation approach.
YLTs can be adjusted by applying weights to the years, which converts a YLT to a WYLT. An example would be adjusting weather and climate risk YLTs to account for the effects of climate variability and change.
A general and principled method for applying weights to YLTs is importance sampling, in which the weight on the year is given by the ratio of the probability of year in the adjusted model to the probability of year in the unadjusted model. Importance sampling can be applied to both fixed parameter YLTs and stochastic parameter YLTs.
WYLTs are less flexible in some ways than YLTs. For instance, two WYLTs with different weights, cannot easily be combined to create a new WYLT. For this reason, it may be useful to convert WYLTs to YLTs. This can be done using the method of repeat-and-delete, in which years with high weights are repeated one or more times and years with low weights are deleted.
Calculating metrics from YLTs and WYLTs
Standard risk metrics can be calculated straightforwardly from YLTs and WYLTs. Some examples are:
The average annual loss
The event exceedance frequencies
The distribution of annual total losses
The distribution of annual maximum losses
References
Insurance industry
Financial risk modeling
Applied mathematics | Year loss table | [
"Mathematics"
] | 1,251 | [
"Applied mathematics"
] |
67,192,205 | https://en.wikipedia.org/wiki/Teck%20Cominco%20smelter | The Teck Cominco smelter, also known as the Teck Cominco Lead-Zinc Smelter, Cominco Smelter, and Trail smelter located in Trail, British Columbia, Canada, is the largest integrated lead-zinc smelter of its kind in the world. It is situated approximately north of the border between British Columbia, Canada and Washington, in the United States, on the Columbia River. It is owned and operated by Vancouver, British Columbia-based Teck Cominco Metals Ltd—renamed Teck Resources.
Since 1896, there has been a copper and gold smelting operation in the area. The original company, Consolidated Mining and Smelting Company of Canada, was founded in 1906 through a merger of several entities then under the control of the Canadian Pacific Railway (CPR). In July 2001, Cominco and Tech Resources merged and in 2008, Teck Cominco renamed itself as Teck. By 2018, the Teck Cominco smelter complex had been in operation for over a century. It provided 1,400 jobs in 2018, making it the largest employer in the small city of Trail, with a population of 7800. In 2017, the smelter produced more than 230,000 tons of zinc, which is used in rustproofing both iron and steel. Teck reported that they had invested CA$525 million in the late 2010s to "improve efficiency and performance at its Trail Operations" and that they intend to invest an added CA$150 million. The Trail Operations contributed CA$169 million to Teck Resources CA$3.3-billion gross profit in 2017.
Overview
The original Trail smelter for the nearby Rossland mines, was founded by the American mining engineer F. Augustus Heinze (1869 – 1914) who had already built a smelter in Butte, Montana. In 1896, Heinze initially incorporated his smelting and mining company in the United States and then in Canada. Within a period of 4 years, Heinze owned the "smelter, mining interests, railway lines, railway charters, and associated land grants." Walter Hull Aldridge (b. 1867), an American mining and metallurgical engineer, took a position with the president of the Canadian Pacific Railway (CPR), Sir William Van Horne, to negotiate a deal with Heinze. Under Aldridge's direction, the CPR's mining interests were incorporated under the name of the Consolidated Mining & Smelting Company, then known as the Consolidated or CM&S. At that time, Consolidated "controlled many of British Columbia's largest lead, silver, gold and copper mines, as well as the large reduction works at Trail."
In 1910, CM&S anticipated the decline of its Rossland mines and purchased the lead-zinc ore-rich Sullivan Mine. At that time, it was difficult to smelt ore from the Sullivan mine because of the presence of iron sulphide. A metallurgist from Ontario, Randolphe 'Ralph' William Diamond who was hired by Consolidated, developed the process known as differential flotation that separated minerals by letting them "float" by "sticking to bubbles formed in certain mixtures of chemicals and oils". This ground-breaking technology increased production at the Sullivan Mine making it profitable for decades. It required a "long-term stable workforce" not just itinerant workers; mining towns grew around the mines and smelter. While 1924, was a peak year in terms of production, by 1927, sulphur dioxide (SO2) emissions from the smelter had contaminated the vegetation and the land of the Columbia River valley in Washington State. Damages were estimated at $350,000 by the International Joint Commission in 1927.
In 1934, Cominco had initiated heavy water research at the smelter but it did not gain momentum until the outbreak of World War II. During the war, the Allies cooperated in researching nuclear fission with the goal of developing an atomic bomb. New research had revealed that heavy water could slow down the uranium neutron, making a chain reaction possible. Under the tenure of Selwyn G. Blaylock as Cominco's president, the smelter was upgraded as part of the Manhattan Project's heavy water production program, under code name the P-9 Project. Princeton University physicist Hugh S. Taylor, who was in charge of United States Office of Scientific Research and Development (OSRD) research on heavy water research, gave Cominco $20,000 towards the upgrade modifications. Cominco produced heavy water for the United States from 1942 until 1956.
In the 1950s, a hydroelectric dam—the Waneta Dam—was built south of Trail on the Pend D’Oreille River, which provided inexpensive electricity to the smelter.
For decades the smelter provided well-paying employment for people who had only a high school education. Intergenerational families worked at the smelter and the company became Trail's "economic and cultural centre."
In the spring of 2017, Teck Resources announced that they were considering a CA$1.2-billion deal to sell its Waneta Dam to BC Hydro. At the time, union members who work at the Teck were concerned about the smelter's future. Teck had expanded its operations worldwide and the Trail operations only contributed CA$92 million of Teck's CA$3.3-billion gross profit in 2017.
Notes
See also
Teck Resources
Trail Smelter dispute
References
Lead and zinc mines in Canada
Zinc smelters
Metallurgical processes
Water pollution in the United States
Trail, British Columbia
Teck Resources
Environmental racism | Teck Cominco smelter | [
"Chemistry",
"Materials_science"
] | 1,166 | [
"Metallurgical processes",
"Metallurgy"
] |
67,194,923 | https://en.wikipedia.org/wiki/Polygon%20with%20holes | In geometry, a polygon with holes is an area-connected planar polygon with one external boundary and one or more interior boundaries (holes). Polygons with holes can be dissected into multiple polygons by adding new edges, so they are not frequently needed.
An ordinary polygon can be called simply-connected, while a polygon-with-holes is multiply-connected. An H-holed-polygon is H-connected.
Degenerate holes
Degenerate cases may be considered, but a well-formed holed-polygon must have no contact between exterior and interior boundaries, or between interior boundaries. Nondegenerate holes should have 3 or more sides, excluding internal point boundaries (monogons) and single edge boundaries (digons).
Boundary orientation
Area fill algorithms in computational lists the external boundary vertices can be listed in counter-clockwise order, and interior boundaries clockwise. This allows the interior area to be defined as left of each edge.
Conversion to ordinary polygon
A polygons with holes can be transformed into an ordinary unicursal boundary path by adding (degenerate) connecting double-edges between boundaries, or by dissecting or triangulating it into 2 or more simple polygons.
In polyhedra
Polygons with holes can be seen as faces in polyhedra, like a cube with a smaller cube externally placed on one of its square faces (augmented), with their common surfaces removed. A toroidal polyhedron can also be defined connecting a holed-face to a holed-faced on the opposite side (excavated). The 1-skeleton (vertices and edges) of a polyhedron with holed-faces is not a connected graph. Each set of connected edges will make a separate polyhedron if their edge-connected holes are replaced with faces.
The Euler characteristic of hole-faced polyhedron is χ = V - E + F = 2(1-g) + H, genus g, for V vertices, E edges, F faces, and H holes in the faces.
Examples
Examples with degenerate holes
A face with a point hole is considered a monogonal hole, adding one vertex, and one edge, and can attached to a degenerate monogonal hosohedron hole, like a cylinder hole with zero radius. A face with a degenerate digon hole adds 2 vertices and 2 coinciding edges, where the two edges attach to two coplanar faces, as a dihedron hole.
See also
Prince Rupert's cube — largest cube that can pass through a unit cube's hole.
References
Polygons
Euclidean plane geometry | Polygon with holes | [
"Mathematics"
] | 545 | [
"Planes (geometry)",
"Euclidean plane geometry"
] |
67,195,296 | https://en.wikipedia.org/wiki/Platinum-195%20nuclear%20magnetic%20resonance | Platinum-195 nuclear magnetic resonance spectroscopy (platinum NMR or 195Pt NMR) is a spectroscopic technique which is used for the detection and characterisation of platinum compounds. The sensitivity of the technique and therefore its diagnostic utility have increased significantly starting from the 1970s, with 195Pt NMR nowadays considered the method of choice for structural elucidation of Pt species in solution.
Examples of compounds routinely characterised with the method include platinum clusters and organoplatinum species such as PtII-based antitumour agents. Additional applications of 195Pt NMR include kinetic and mechanistic studies or investigations on drug binding.
195Pt magnetic properties
Among the naturally occurring isotopes of platinum, 195Pt is the most abundant (33.8%) and the only one with non-zero spin I=1/2. The magnetic properties of the nucleus are considered favourable; the high natural abundance coupled with a medium gyromagnetic ratio (5.768×107 rad T−1 s−1) result in good 195Pt NMR signal receptivity, 19 times that of 13C (but still only 0.0034 times that of 1H).
The resonance frequency (relative to a 100 MHz 1H NMR instrument) is approximately 21.4 MHz, close to the 13C resonance at 25.1 MHz.
Chemical shifts
The chemical shifts of 195Pt nuclei span a very large range of over 13000 ppm (cf. with ~300 ppm range for 13C). The NMR signals are also very sharp and highly sensitive to the platinum chemical environment (oxidation state, ligand identity and field strength, coordination number, etc.). Therefore, substituting even very similar ligands can result in shift changes in the order of hundreds of ppm which stand out on the spectrum and are easily monitored.
The reference compound typically chosen for 195Pt NMR experiments is 1.2 M sodium hexachloroplatinate(IV) (Na2PtCl6) in D2O; this platinum(IV) complex is preferred due to its commercial availability, chemical stability, lower price relative to other platinum compounds, and high solubility which enables spectrum recording within minutes. Less soluble ionic platinum complexes have spectrum recording times of about an hour, whereas the borderline insoluble neutral complexes may require overnight measurements.
The high sensitivity of the experiment means that contributions from different chlorine isotopes in the reference compound or other species can be resolved at high magnetic field strengths, giving a ±5 ppm uncertainty in reported shift values (which is, however, negligible in view of the 13000 ppm overall range).
Couplings
Coupling of 195Pt to 1H, 13C, 31P, 19F or 15N has been reported through one up to four bonds (1J to 4J) and is commonly studied to provide additional structural information for platinum complexes. The ~34% abundance of 195Pt (with the remaining 66% of natural Pt being NMR-inactive) means that this coupling appears in the respective 1H/31P/15N/13C NMR spectra as satellite peaks (cf. 13C satellites) which, for example, result in 17:66:17 patterns for singlets.
The trans influence in 16 e− square planar PtII complexes has been studied by comparing the magnitude of coupling constants in the cis- and trans- isomers.
Complicated homonuclear couplings ranging from 60 to 9000 Hz for 1J(195Pt–195Pt) are of interest in the context of platinum cluster compounds.
References
Nuclear magnetic resonance
Platinum | Platinum-195 nuclear magnetic resonance | [
"Physics",
"Chemistry"
] | 739 | [
"Nuclear magnetic resonance",
"Nuclear physics"
] |
67,195,491 | https://en.wikipedia.org/wiki/Cyclolysis | Cyclolysis is a process in which a cyclonic circulation weakens and deteriorates. Cyclolysis is the opposite of cyclogenesis.
Extratropical cyclones
Extratropical cyclones usually undergo cyclolysis after an occluded front forms, which separates the center of the cyclone from the warm air. With the center of the cyclone surrounded by cool air, the temperature difference or baroclinity begins to decline, and the jet stream persisting over the strongest areas of baroclinity which is not over the center of the cyclone, which makes it so that the jet stream is unable to support the system. This usually causes decay and dissipation of the cyclone. When an extratropical cyclone has completed cyclolysis, it usually is not connected to any weather fronts. Extratropical cyclones in the northern hemisphere tend to undergo cyclolysis over the northeast Atlantic Ocean, northwestern Europe, the Gulf of Alaska, the Pacific Northwest, northeast Canada, central Russia, or the eastern Mediterranean sea. In the southern hemisphere, most extratropical cyclones undergo cyclolysis north of 50°S.
Tropical cyclones
Tropical cyclones often undergo cyclolysis after making landfall, especially if the land is mountainous as the friction with the terrain is increased. Its supply of warm, moist maritime air is also cut off when it moves over land. However, the brown ocean effect may cause a tropical cyclone to maintain its strength, or even intensify over land. A tropical cyclone may also undergo cyclolysis if it moves over water cooler than as this will cause it to lose its tropical characteristics and become a remnant low. However, these remnant cyclones may persist for a few more days. Excessive wind shear can also cause cyclolysis as it causes the convection that powers the tropical cyclone to move away from the center.
Mesocyclones
Mesocyclones are localized storms, approximately to in diameter within strong thunderstorms. Thunderstorms containing persistent mesocyclones are supercell thunderstorms. Mesocyclones typically undergo cyclolysis when the gust front of the storm blocks off the updraft. At this point, cyclonic circulation weakens, and tornadic supercells lift off the ground. The thunderstorm begins to dissipate as well.
References
Atmospheric dynamics
Synoptic meteorology and weather | Cyclolysis | [
"Chemistry"
] | 486 | [
"Atmospheric dynamics",
"Fluid dynamics"
] |
67,195,768 | https://en.wikipedia.org/wiki/USA-293 | USA-293, also known as GPS-III SV02 or Magellan, is a United States navigation satellite which forms part of the Global Positioning System. It was the second GPS Block III satellite to be launched.
Satellite
SV02 is the second GPS Block III satellite to be launched. Ordered in 2008, technical delays to the first satellite in the program, SV01, pushed launch back to 2019.
The spacecraft is built on the Lockheed Martin A2100 satellite bus, and weighs .
Launch
USA-293 was launched by United Launch Alliance on 22 August 2019 at 13:06 UTC atop a Delta IV Medium. The launch was the final flight of the single-core Delta IV. The launch took place from Cape Canaveral Space Launch Complex 37, and deployed USA-293 directly into a semi-synchronous orbit.
Orbit
As of 2021, USA-293 was in a 55.4 degree inclination orbit with a perigee of and an apogee of .
References
Spacecraft launched in 2019
GPS satellites
USA satellites
Spacecraft launched by Delta rockets | USA-293 | [
"Technology"
] | 213 | [
"Global Positioning System",
"GPS satellites"
] |
67,195,961 | https://en.wikipedia.org/wiki/Aristotle%27s%20axiom | Aristotle's axiom is an axiom in the foundations of geometry, proposed by Aristotle in On the Heavens that states:
If is an acute angle and AB is any segment, then there exists a point P on the ray and a point Q on the ray , such that PQ is perpendicular to OX and PQ > AB.
Aristotle's axiom is a consequence of the Archimedean property, and the conjunction of Aristotle's axiom and the Lotschnittaxiom, which states that "Perpendiculars raised on each side of a right angle intersect", is equivalent to the Parallel Postulate.
Without the parallel postulate, Aristotle's axiom is equivalent to each of the following three incidence-geometric statements:
Given a line A and a point P on A, as well as two intersecting lines M and N, both parallel to A there exists a line G through P which intersects M but not N.
Given a line A as well as two intersecting lines M and N, both parallel to A, there exists a line G which intersects A and M, but not N.
Given a line A and two distinct intersecting lines M and N, each different from A, there exists a line G which intersects A and M, but not N.
References
Sources
Foundations of geometry
Aristotelianism | Aristotle's axiom | [
"Mathematics"
] | 268 | [
"Foundations of geometry",
"Mathematical axioms"
] |
67,196,020 | https://en.wikipedia.org/wiki/USA-304 | USA-304, also known as GPS-III SV03 or Matthew Henson, is a United States navigation satellite which forms part of the Global Positioning System. It was the third GPS Block III satellite to be launched.
Satellite
SV03 is the third GPS Block III satellite to be launched. Ordered in 2008, launch was pushed back several times to 2020 due to delays with the first and second satellites.
The spacecraft is built on the Lockheed Martin A2100 satellite bus, and weighs in at .
Launch
USA-304 was launched by SpaceX on 30 June 2020 at 20:10 UTC atop Falcon 9 booster B1060. The launch took place from SLC-40 of the Cape Canaveral Air Force Station, and placed USA-304 directly into semi-synchronous orbit. About eight minutes after launch, Falcon 9 B1060 successfully landed on Just Read the Instructions.
Orbit
As of 2021, USA-304 was in a 55.2 degree inclination orbit with a perigee of and an apogee of .
Notes
References
GPS satellites
USA satellites
SpaceX military payloads
Spacecraft launched in 2020 | USA-304 | [
"Technology"
] | 225 | [
"Global Positioning System",
"GPS satellites"
] |
67,197,507 | https://en.wikipedia.org/wiki/Gouy%E2%80%93Stodola%20theorem | In thermodynamics and thermal physics, the Gouy-Stodola theorem is an important theorem for the quantification of irreversibilities in an open system, and aids in the exergy analysis of thermodynamic processes. It asserts that the rate at which work is lost during a process, or at which exergy is destroyed, is proportional to the rate at which entropy is generated, and that the proportionality coefficient is the temperature of the ambient heat reservoir. In the literature, the theorem often appears in a slightly modified form, changing the proportionality coefficient.
The theorem is named jointly after the French physicist Georges Gouy and Slovak physicist Aurel Stodola, who demonstrated the theorem in 1889 and 1905 respectively. Gouy used it while working on exergy and utilisable energy, and Stodola while working on steam and gas engines.
Overview
The Gouy-Stodola theorem is often applied upon an open thermodynamic system, which can exchange heat with some thermal reservoirs. It holds both for systems which cannot exchange mass, and systems which mass can enter and leave.
Observe such a system, as sketched in the image shown, as it is going through some process. It is in contact with multiple reservoirs, of which one, that at temperature , is the environment reservoir. During the process, the system produces work and generates entropy. Under these conditions, the theorem has two general forms.
Work form
The reversible work is the maximal useful work which can be obtained, , and can only be fully utilized in an ideal reversible process. An irreversible process produces some work , which is less than . The lost work is then ; in other words, is the work which was lost or not exploited during the process due to irreversibilities. In terms of lost work, the theorem generally stateswhere is the rate at which work is lost, and is the rate at which entropy is generated. Time derivatives are denoted by dots. The theorem, as stated above, holds only for the entire thermodynamic universe - the system along with its surroundings, together:where the index "tot" denotes the total quantities produced within or by the entire universe.
Note that is a relative quantity, in that it is measured in relation to a specific thermal reservoir. In the above equations, is defined in reference to the environment reservoir, at . When comparing the actual process to an ideal, reversible process between the same endpoints (in order to evaluate , so as to find the value of ), only the heat interaction with the reference reservoir is allowed to vary. The heat interactions between the system and other reservoirs are kept the same. So, if a different reference reservoir is chosen, the theorem would read , where this time is in relation to , and in the corresponding reversible process, only the heat interaction with is different.
By integrating over the lifetime of the process, the theorem can also be expressed in terms of final quantities, rather than rates: .
Adiabatic case
The theorem also holds for adiabatic processes. That is, for closed systems, which are not in thermal contact with any heat reservoirs.
Similarly to the non-adiabatic case, the lost work is measured relative to some reference reservoir . Even though the process itself is adiabatic, the corresponding reversible process may not be, and might require heat exchange with the reference reservoir. Thus, this can be thought of as a special case of the above statement of the theorem - an adiabatic process is one for which the heat interactions with all reservoirs are zero, and in the reversible process, only the heat interaction with the reference thermal reservoir may be different.
The adiabatic case of the theorem holds also for the other formulation of the theorem, presented below.
Exergy form
The exergy of the system is the maximal amount of useful work that the system can generate, during a process which brings it to equilibrium with its environment, or the amount of energy available. During an irreversible process, such as heat exchanges with reservoirs, exergy is destroyed. Generally, the theorem states thatwhere is the rate at which exergy is destroyed, and is the rate at which entropy is generated. As above, time derivatives are denoted by dots.
Unlike the lost work formulation, this version of the theorem holds for both the system (the control volume) and for its surroundings (the environment and the thermal reservoirs) separately:andwhere the index "sys" denotes quantities produced within or by the system itself, and "surr" within or by the surroundings. Therefore, summing these two forms, the theorem also holds for the thermodynamic universe as a whole:where the index "tot" denotes the total quantities of the entire universe.
Thus, the exergy formulation of the theorem is less limited, as it can be applied on different regions separately. Nevertheless, the work form is used more often.
The proof of the theorem, in both forms, uses the first law of thermodynamics, writing out the terms , , and in the relevant regions, and comparing them.
Modified coefficient and effective temperature
In many cases, it is preferable to use a slightly modified version of the Gouy-Stodola theorem in work form, where is replaced by some effective temperature. When this is done, it often enlarges the scope of the theorem, and adapts it to be applicable to more systems or situations. For example, the corrections elaborated below are only necessary when the system exchanges heat with more than one reservoir - if it exchanges heat only at the environmental temperature , the simple form above holds true. Additionally, modifications may change the reversible process to which the real process is compared in calculating .
The modified theorem then readswhere is the effective temperature.
For a flow process, let denote the specific entropy (entropy per unit mass) at the inlet, where mass flows in, and the specific entropy at the outlet, where mass flows out. Similarly, denote the specific enthalpies by and . The inlet and outlet, in this case, function as initial and final states a process: mass enters the system at an initial state (the inlet, indexed "1"), undergoes some process, and then leaves at a final state (the outlet, indexed "2").
This process is then compared to a reversible process, with the same initial state, but with a (possibly) different final state. The theoretical specific entropy and enthalpy after this ideal, isentropic process are given by and , respectively. When the actual process is compared to this theoretical reversible process and is evaluated, the proper effective temperature is given byIn general, lies somewhere in between the final temperature in the actual process and the final temperature in the theoretical reversible process .
This equation above can sometimes be simplified. If both the pressure and the specific heat capacity remain constant, then the changes in enthalpy and entropy can be written in terms of the temperatures, andHowever, it is important to note that this version of the theorem doesn't relate the exact values which the original theorem does. Specifically, in comparing the actual process to a reversible one, the modified version allows the final state to be different between the two. This is in contrast to the original version, wherein reversible process is constructed to match so that the final states are the same.
Applications
In general, the Gouy-Stodola theorem is used to quantify irreversibilities in a system and to perform exergy analysis. That is, it allows one to take a thermodynamic system and better understand how inefficient it is (energy-wise), how much work is lost, how much room there is for improvement and where. The second law of thermodynamics states, in essence, that the entropy of a system only increases. Over time, thermodynamic systems tend to gain entropy and lose energy (in approaching equilibrium): thus, the entropy is "somehow" related to how much exergy or potential for useful work a system has. The Gouy-Stodola theorem provides a concrete link. For the most part, this is how the theorem is used - to find and quantify inefficiencies in a system.
Flow processes
A flow process is a type of thermodynamic process, where matter flows in and out of an open system called the control volume. Such a process may be steady, meaning that the matter and energy flowing into and out of the system are constant through time. It can also be unsteady, or transient, meaning that the flows may change and differ at different times.
Many proofs of the theorem demonstrate it specifically for flow systems. Thus, the theorem is particularly useful in performing exergy analysis on such systems.
Vapor compression and absorption
The Gouy-Stodola theorem is often applied to refrigeration cycles. These are thermodynamic cycles or mechanical systems where external work can be used to move heat from low temperature sources to high temperature sinks, or vice versa. Specifically, the theorem is useful in analyzing vapor compression and vapor absorption refrigeration cycles.
The theorem can help identify which components of a system have major irreversibilities, and how much exergy they destroy. It can be used to find at which temperatures the performance is optimal, or what size system should be constructed. Overall, that is, the Gouy-Stodola theorem is a tool to find and quantify inefficiencies in a system, and can point to how to minimize them - this is the goal of exergy analysis. When the theorem is used for these purposes, it is usually applied in its modified form.
In ecology
Macroscopically, the theorem may be useful environmentally, in ecophysics. An ecosystem is a complex system, where many factors and components interact, some biotic and some abiotic. The Gouy-Stodola theorem can find how much entropy is generated by each part of the system, or how much work is lost. Where there is human interference in an ecosystem, whether the ecosystem continues to exist or is lost may depend on how many irreversibilities it can support. The amount of entropy which is generated or the amount of work the system can perform may vary. Hence, two different states (for example, a healthy forest versus one which has undergone significant deforestation) of the same ecosystem may be compared in terms of entropy generation, and this may be used to evaluate the sustainability of the ecosystem under human interference.
In biology
The theorem is also useful on a more microscopic scale, in biology. Living systems, such as cells, can be analyzed thermodynamically. They are rather complex systems, where many energy transformations occur, and they often waste heat. Hence, the Gouy-Stodola theorem may be useful, in certain situations, to perform exergy analysis on such systems. In particular, it may help to highlight differences between healthy and diseased cells.
Generally, the theorem may find applications in fields of biomedicine, or where biology and physics cross over, such as biochemical engineering thermodynamics.
As a variational principle
A variational principle in physics, such as the principle of least action or Fermat's principle in optics, allows one to describe the system in a global manner and to solve it using the calculus of variations. In thermodynamics, such a principle would allow a Lagrangian formulation. The Gouy-Stodola theorem can be used as the basis for such a variational principle, in thermodynamics. It has been proven to satisfy the necessary conditions.
This is fundamentally different from most of the theorem's other uses - here, it isn't being applied in order to locate components with irreversibilities or loss of exergy, but rather helps give some more general information about the system.
References
Thermodynamics | Gouy–Stodola theorem | [
"Physics",
"Chemistry",
"Mathematics"
] | 2,479 | [
"Thermodynamics",
"Dynamical systems"
] |
53,009,580 | https://en.wikipedia.org/wiki/Brown%E2%80%93Gitler%20spectrum | In the mathematical discipline of topology, the Brown–Gitler spectrum is a spectrum whose cohomology is a certain cyclic module over the Steenrod algebra.
Brown–Gitler spectra are defined by the isomorphism:
History
The concept was introduced by mathematicians Edgar H. Brown and Samuel Gitler in a 1973 paper.
In topology, Brown–Gitler spectrum is related to the concepts of the Segal conjecture
(proven in 1984) and the Burnside ring.
Applications
Brown–Gitler spectra have had many important applications in homotopy theory.
References
External links
Topology | Brown–Gitler spectrum | [
"Physics",
"Mathematics"
] | 116 | [
"Spacetime",
"Topology",
"Space",
"Geometry"
] |
53,010,429 | https://en.wikipedia.org/wiki/Tridentate%20ligand | A tridentate ligand (or terdentate ligand) is a ligand that has three atoms that can function as donor atoms in a coordination complex.
Well-known tridentate ligands include diethylenetriamine with three nitrogen donor atoms, and the iminodiacetate anion which consists of one deprotonated amine nitrogen and a pair of carboxylate groups.
An octahedrally coordinated atom has six positions around it. Two tridentate ligands may form a complex with such an atom. There are two possible arrangements for such a complex: fac where the coordination is in a triangle on one face of the octahedron, and mer where the coordinating atoms are in an arc around the central atom, with two atoms of the ligand opposite each other. Fac tridentate ligands are termed scorpionate ligands, especially in reference to polypyrazolylborates.
If the tridentate ligand is not symmetrical, then in the fac complexes in octahedral coordination there are three possible isomers. In the mer complexes there are two enantiomers, mirror images of each other.
List
See also
Tripodal ligand
References
Coordination chemistry
Ligands | Tridentate ligand | [
"Chemistry"
] | 245 | [
"Ligands",
"Coordination chemistry"
] |
53,010,596 | https://en.wikipedia.org/wiki/Zhi-Xun%20Shen | Zhi-Xun Shen (; born July 1962) is a Chinese-American experimental and solid state physicist who is a professor at Stanford University. He is particularly noted for his ARPES studies on high-temperature superconductors.
Life
Shen was born in July 1962 in Zhejiang, China. He graduated from Fudan University with a B.S. in 1983, and went to the United States through the CUSPEA program organized by T. D. Lee. He earned his M.S. degree in 1985 at Rutgers University. In 1989 he received a PhD in applied physics from Stanford University. In 1991 he became assistant professor, in 1996 associate professor, and in 2000 full professor at Stanford University. Since 2010 he is chief scientist at SLAC (at the Stanford Synchrotron Radiation Lightsource, SSRL), and since 2006 he is founding director of the Stanford Institute for Materials and Energy Sciences (SIMES). Furthermore, from 2005 to 2008 he was director of the Geballe Laboratory for Advance Materials.
Research
He developed several precision instruments, e.g. for synchrotron radiation sources, helium lamps for UV and angle-resolved photoemission spectroscopy (ARPES), and he used these to study high-temperature superconductors. For example, his group in 2010 obtained convincing evidence that the pseudogap phase of the cuprate high-temperature superconductors, which was discovered in the mid 1990s, indeed is an independent phase (independent from the metallic and superconducting phases), which reaches into the superconducting phase. Besides ARPES techniques in the UV regime, he also employs x-ray diffraction methods.
He developed near-field microwave microscopy (scanning microwave impedance microscopy) based on atomic force microscopes for studies on mesoscopic length scales, e.g. nanostructured materials. Using this, he addresses applications such as new techniques for solar collectors (Photo Enhanced Thermionic Emission, PETE).
Awards
In 1999 he gave the APS Centennial lecture and in 2003 was elected fellow of the American Physical Society (APS), In 2000 he received the Kamerlingh Onnes Prize and in 2009 the Ernest Orlando Lawrence Award, and 2011 together with Peter Johnson the Oliver E. Buckley Condensed Matter Prize. In 2015 he was elected to the National Academy of Sciences. In 2017, Shen was elected as a foreign member of the Chinese Academy of Sciences.
References
External links
Homepage in Stanford
Oliver Buckley Prize
Further Homepage of Shen
1962 births
Living people
20th-century American physicists
21st-century American physicists
Chinese emigrants to the United States
Foreign members of the Chinese Academy of Sciences
Fudan University alumni
Members of the United States National Academy of Sciences
Educators from Wenzhou
Experimental physicists
Physicists from Zhejiang
Rutgers University alumni
Scientists from Wenzhou
Stanford University alumni
Stanford University faculty
Fellows of the American Physical Society
Oliver E. Buckley Condensed Matter Prize winners | Zhi-Xun Shen | [
"Physics"
] | 595 | [
"Experimental physics",
"Experimental physicists"
] |
53,010,729 | https://en.wikipedia.org/wiki/Mirror%20life | Mirror life (also called mirror-image life) is a hypothetical form of life with mirror-reflected molecular building blocks. The possibility of mirror life was first discussed by Louis Pasteur. This alternative life form has never been discovered in nature, but efforts to build a mirror-image version of biology's molecular machinery are underway.
In December 2024, a broad coalition of scientists, including leading synthetic biology researchers and Nobel laureates, warned that the creation of mirror life, including mirror bacteria, could cause "unprecedented and irreversible harm" to human health and ecosystems worldwide. Its potential to escape immune defenses and invade natural ecosystems might lead to "pervasive lethal infections in a substantial fraction of plant and animal species, including humans." Given these risks, the scientists concluded that mirror organisms should not be created without compelling evidence of safety.
Homochirality
Many of the essential molecules for life on Earth can exist in two mirror-image forms, often called "left-handed" and "right-handed", where handedness refers to the direction in which polarized light skews when beamed through a pure solution of the molecule, but living organisms do not use both. RNA and DNA contain only right-handed sugars; proteins are exclusively composed of left-handed amino acids, although many bacteria and fungi are able to synthesise non-ribosomal peptides containing right-handed amino acids, as the example of peptidoglycan synthesis shows. This phenomenon is known as homochirality. It is not known whether homochirality emerged before or after life, whether the building blocks of life must have this particular chirality, or indeed whether life needs to be homochiral. Protein chains built from amino acids of mixed chirality tend not to fold or function well, but mirror-image proteins have been constructed that have identical function but on substrates of opposite handedness.
The concept
Advances in synthetic biology, like synthesizing viruses since 2002, partially synthetic bacteria in 2010, and synthetic ribosomes in 2013, may lead to the possibility of fully synthesizing a living cell from small molecules, which could enable synthesizing mirror cells from mirrored versions (enantiomers) of life's building-block molecules. Some proteins have been synthesized in mirror-image versions, including polymerase in 2016.
Reconstructing regular lifeforms in mirror-image form, using the mirror-image (chiral) reflection of their cellular components, could be achieved by substituting left-handed amino acids with right-handed ones, in order to create mirror reflections of proteins, and likewise substituting right-handed with left-handed nucleic acids. Because the phospholipids of cell membranes are also chiral, American geneticist George Church proposed using an achiral fatty acid instead of mirror-image phospholipids for the membrane.
Electromagnetic force (chemistry) is unchanged under such molecular reflection transformation (P-symmetry). There is a small alteration of weak interactions under reflection, which can produce very small corrections that theoretically favor the natural enantiomers of amino acids and sugars, but it is unknown if this effect is large enough to affect the functionality of mirror biomolecules or explain homochirality in nature.
Mirror animals would need to feed on reflected food, produced by reflected plants. Mirror viruses would not be able to attack natural cells, just as natural viruses would not be able to attack mirror cells.
Mirror life presents potential dangers. For example, a chiral-mirror version of cyanobacteria, which only needs achiral nutrients and light for photosynthesis, could take over Earth's ecosystem due to lack of natural enemies, disturbing the bottom of the food chain by producing mirror versions of the required sugars. Some bacteria can digest L-Glucose; exceptions like this would give some rare lifeforms an unanticipated advantage.
Direct applications
Direct application of mirror-chiral organisms can be mass production of enantiomers (mirror-image) of molecules produced by normal life.
Enantiopure drugs - some pharmaceuticals have shown different activity depending on enantiomeric form,
Aptamers (L-ribonucleic acid aptamers): "That makes mirror-image biochemistry a potentially lucrative business. One company that hopes so is Noxxon Pharma in Berlin. It uses laborious chemical synthesis to make mirror-image forms of short strands of DNA or RNA called aptamers, which bind to therapeutic targets such as proteins in the body to block their activity. The firm has several mirror-aptamer candidates in human trials for diseases including cancer; the idea is that their efficacy might be improved because they aren't degraded by the body's enzymes. A process to replicate mirror-image DNA could offer a much easier route to making the aptamers, says Sven Klussmann, Noxxon Pharma's chief scientific officer."
L-Glucose, enantiomer of standard glucose, Tests showed that it tastes likes standard sugar, but is not metabolized the same way. However, it was never marketed due to excessive manufacturing costs. More recent research allows cheap production with high yields; however the authors state that it is not usable as a sweetener due to laxative effects.
In fiction
The creation of a mirror human is the basis of the 1950 short story "Technical Error" by Arthur C. Clarke. In this story, a physical accident transforms a person into his mirror image, speculatively explained by travel through a fourth physical dimension. H. G. Wells' The Plattner Story (1896) is based on a similar idea.
In the 1970 Star Trek novel Spock Must Die! by James Blish, the science officer of the USS Enterprise is replicated in mirror form by a transporter mishap. He locks himself in the sick bay where he is able to synthesize mirror forms of basic nutrients needed for his survival.
An alien machine that reverses chirality, and a blood-symbiont that functions properly only when in one chirality, were central to Roger Zelazny's 1976 novel Doorways in the Sand.
On the titular planet of Sheri S. Tepper's 1989 novel Grass, some lifeforms have evolved to use the right-handed isomer of alanine.
In the Mass Effect series, chirality of amino acids in foodstuffs is discussed often in both dialogue and encyclopedia files.
In the 2014 science fiction novel Cibola Burn by James S. A. Corey, the planet Ilus has indigenous life with partially-mirrored chirality. This renders human colonists unable to digest native flora and fauna, and greatly complicates conventional farming. Consequently, the colonists have to rely upon hydroponic farming and food importation.
In the 2017 Daniel Suarez novel Change Agent, an antagonist, Otto, nicknamed the "Mirror Man", is revealed to be a genetically-engineered mirror human. He views other humans with disdain and causes them to feel an inexplicable repulsion by his very presence.
The concept is used during Ryan North's 2023 run on Fantastic Four as an existential threat towards the human population.
See also
Xenobiology
Mirror matter – A hypothetical form of matter that interacts only weakly with normal matter, which could form mirror planets, potentially inhabited by mirror matter life.
References
Chirality
Synthetic biology
Hypothetical life forms | Mirror life | [
"Physics",
"Chemistry",
"Engineering",
"Biology"
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"Pharmacology",
"Biological engineering",
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"Hypothetical life forms",
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"Chirality",
"Bioinformatics",
"Molecular genetics",
"Asymmetry",
"Biological hypotheses",
"Symmetry"
] |
53,010,758 | https://en.wikipedia.org/wiki/Short%20range%20order | In crystallography, short range order refers to the regular and predictable arrangement (i.e. crystalline lattice) of atoms over a short distance, usually with one or two atom spacings. However, this regularity described by short-range order does not necessarily apply to a larger area. Examples of materials with short range order include amorphous materials such as wax, glass and liquids as well as the collagen fibrils of the stroma in the cornea.
Besides ordering of atoms, short-range ordering of vacancies are also possible. Example of systems with short-range ordering of oxygen-vacancies include oxygen-deficient stoichiometries of the superconductors , ; as well as perovskites and novel bismuth sillenites.
See also
Order and disorder
Structure of liquids and glasses
References
Statistical mechanics | Short range order | [
"Physics"
] | 179 | [
"Statistical mechanics"
] |
53,011,066 | https://en.wikipedia.org/wiki/LG%20L%20Fino | The LG L Fino is an Android smartphone/phablet designed and manufactured by LG Electronics. It was released on 10 August 2014.
Specifications
Design
LG L Fino features a design similar to the LG G3. The phone has a 4.5 inch display with sizable bezels; the top bezel includes the front-facing camera and the earpiece, and the bottom bezel has an "LG" logo. On the side frame, there is a 3.5 mm headphone jack and a microphone at the top, and there is a microUSB port and a microphone at the bottom. Unlike most of the smartphones, the power button and the volume buttons are located at the back under the rear-facing camera instead of the side frame; there is also an LED flash, an "LG" logo and a speaker at the back. The phone is made of plastic and the back cover is removable, removing the back cover reveals the removable battery.
LG L Fino is available in white, black, gold, red and green.
Hardware
Source:
LG L Fino features:the Qualcomm Snapdragon 200 system-on-chip with a 1.2 GHz quad-core ARM Cortex-A7 CPU and an Adreno 302 GPU. The phone comes with 1 GB RAM and 4 GB internal storage expandable through the microSD card slot. It has a 4.5 inch WVGA (480x800 pixels resolution) capacitive touchscreen with 207 ppi pixel density. It has a 1900 mAh removable Li-Ion battery.
LG L Fino has an 8 MP rear-facing camera with LED flash, Gesture Shot and Touch & Shoot, and a 0.3 MP (VGA) front-facing camera with Front Camera Light. The rear-facing camera can record videos at 800x480 pixels resolution and the front-facing camera can record videos at 640x480 pixels resolution.
Software
LG L Fino runs on Android 4.4.2 KitKat with LG's custom user interface. It comes with LG's Knock Code, tap to unlock and QuickMemo features, and LG's camera application.
See also
List of LG mobile phones
List of Android devices
Smartphone
LG G series
References
External links
Gadgets
fr
Android (operating system) devices
LG Electronics smartphones
Mobile phones introduced in 2013 | LG L Fino | [
"Technology"
] | 501 | [
"Mobile technology stubs",
"Mobile phone stubs"
] |
53,011,652 | https://en.wikipedia.org/wiki/Half%20a%20Moon%20and%20One%20Whole%20Star | Half a Moon and One Whole Star is a 1986 book by Crescent Dragonwagon and illustrator Jerry Pinkney about a girl, Susan, who falls asleep in her bed, while the world continues outside.
Reception
Publishers Weekly in a review of Half a Moon and One Whole Star, wrote " Half A Moon and One Whole Star is an exceptional children's book: a work of art, both literary and visual." and School Library Journal called it "a soft symphony of sleep in which participants are both real and imagined."
Kirkus Reviews wrote "The cadence and the sensual images of the text, coupled with the artist's direct, yet subtly disjointed pictures in vivid watery colors, combine for a harmonious nighttime symphony of sound and color."
Half a Moon received the 1987 Coretta Scott King Illustrator Award.
References
1986 children's books
1986 poetry books
American picture books
American poetry collections
Children's poetry books
Picture books by Jerry Pinkney
Coretta Scott King Award–winning works
Sleep in fiction | Half a Moon and One Whole Star | [
"Biology"
] | 206 | [
"Behavior",
"Sleep in fiction",
"Sleep"
] |
53,014,205 | https://en.wikipedia.org/wiki/SMIM23 | SMIM23 or Small Integral Membrane Protein 23 is a protein which in humans is encoded by the SMIM23 or c5orf50 gene. The longer mRNA isoform is 519 nucleotides which translates to 172 amino acids of a protein. In recent advancements, researchers have identified this gene, along with a few others, could potentially play a role in how facial morphology arises in humans.
Gene
SMIM23 is a protein-encoding gene. Basic information about its aliases and chromosome location are given in the table. The schematic of the chromosome helps to visualize the location of the gene.
mRNA
While the gene has two splice isoforms (isoforms X1 and X2), it has three exon/exon boundaries indicating four exons (nucleotide 1-105, 106-157, 158-225, and 226-519).
Protein
Physical features
SMIM23 notably has a transmembrane domain.
The predicted isoelectric point for the unmodified/unprocessed protein in mice is 5.779 while only the transmembrane region in humans has an isoelectric point of 5.928
The gene appears to be Leucine and Glutamic Acid rich though not at any usually high number. It is also weak in all other amino acids besides Alanine, Serine, and Glutamine.
The region underlined in the conceptual translation was predicted to be an Involucrin repeat.
Post-Translational modifications
The transmembrane region is 1674.2 daltons while the whole protein is 200008.51 Da. This is very similar to what was found with UniProt where predicted molecular weight was 20.025 kDa. Antibody kits were investigated to see banding pattern and weight changes that may have occurred post translation. C5orf50 Polyclonal Antibody from ThermoFisher Scientific has a Western Blot banding pattern at 40 kDa. This predicts that there is a significant amount of post-translational modification by addition of large components.
There are many phosphorylation sites along its sequence including two protein kinase C phosphorylation sites, cAMP- and cGMP-dependent protein kinase phosphorylation site, and a tyrosine kinase phosphorylation site. There is also a confident potential C-terminal GPI-Modification Site.
Secondary structure
There are two stretches of alpha helices from amino acid 33 to 49 and 89 to 136 based on evidence from various programs that predict secondary structure. The most informative of all the programs from the ones investigated is PELE on Biology Workbench.
A 3D protein structure was predicted to look like a series of helices, similar to what was predicted by other programs.
Subcellular localization
This human integral membrane protein is predicted to be found in the endoplasmic reticulum. The same kind of investigation of protein localization in other types of species returned conflicting results. Many programs predicted the protein to be present in the cytosol. This suggests the possibility of incorrect naming, i.e. the protein may not be integral membrane due to other predicted locations. This type of conclusion will require further information.
Expression
Not enough consensus exists as to where in the body SMIM23 is expressed. Databases indicate mainly in the testes, but this may be due to the lack of data.
Regulation of Expression
The promoter region of SMIM23 is approximately 1192 nucleotides long with various predicted transcription factors.
Regulation in the secondary structure is a predicted stem-loop in the 5' UTR region with a few areas of conservation across species.
Function and clinical significance
Novel research has suggested that how face shape arises in individuals may be influenced by a set of genes. This set includes SMIM23. Though in the paper the gene is referred to by an alias (C5orf50), it is clear that the scientists have gathered a list of five genes that likely determine facial shape. This is specifically people of European descent. These findings are supported by replicating phenotypes of each specific gene and statistical analysis. Just like findings elsewhere, the article mentions SMIM23 that likely codes for an unknown transmembrane protein. There have also been studies where a set of genes including SMIM23 may influence human height. Furthermore, a great deal of research is being done on chromosome 5 in general to understand roles of certain genes on it including SMIM23. This could one day provide insight into this gene’s specific roles on the chromosome itself.
Interacting proteins
The following proteins are predicted to interact with SMIM23.
Cilia And Flagella Associated Protein 43 also known as CFAP43 or WDR96 is the most confident of the predicted functional partners and is a tryptophan-aspartic acid repeat domain.
SFR1 is SWI5-dependent recombination repair 1 which is a component of the SWI5-SFR1 complex, a complex required for double-strand break repair via homologous recombination.
COL17A1 is collagen. Specifically type XVII, alpha 1. This may play a role in overall protein structure.
PRDM16 binds to DNA and acts as a transcriptional regulator. It functions in the differentiation between white and brown adipose tissue. It can also be a repressor of transforming growth factor-beta signaling.
Homology and evolution
There are no known paralogs.
There are around 100+ known orthologs which range from primates to small ground animals. From these investigations and that of sequence similarity, an ortholog space can be discussed. The closest relatives to humans with the SMIM23 gene were in primates so two types of monkeys were picked which diverged around 29.4 million years ago and had sequence similarities in the high 70s. Slightly more distant relatives with the gene come from a wide variety of animals from horses, to sea mammals, to bats, and more which all have similarities between 62-69%. Lastly, some distantly related orthologs were included like the Tasmanian devil and various scavenger animals which have similarities between 40-61%.
It is interesting to see how some portions are still highly conserved (see conceptual translation above). The most interesting motif is tryptophan 124, leucine 125, and aspartic acid 126. Lastly, in BLAST a protein family of unknown function was returned. There are two small conserved sequences part of the DUF4635 motif (LEQ and DLE). So though not completely conserved in the alignments done with SMIM23, these were labeled in the conceptual translation.
Orthologs
The protein was not found in bacteria, archaea, protists, plants, fungi, invertebrate, reptiles, and birds. All the found orthologs were under mammals. An unrooted phylogenetic tree of SMIM23 was created with a few close, moderately related, and distant orthologs (listed in table). Here, larger the distance (length of line), longer the time to last common ancestor. Sequence identity refers to similar amino acids while similarity refers to amino acid match.
References
Suggested Reading
Liu F, van der Lijn F, Schurmann C, Zhu G, Chakravarty MM, Hysi PG, et al. (2012) A Genome-Wide Association Study Identifies Five Loci Influencing Facial Morphology in Europeans. PLoS Genet 8(9): e1002932. https://doi.org/10.1371/journal.pgen.1002932
Lowe JK, Maller JB, Pe'er I, Neale BM, Salit J, Kenny EE, et al. (2009) Genome-Wide Association Studies in an Isolated Founder Population from the Pacific Island of Kosrae. PLoS Genet 5(2): e1000365. https://doi.org/10.1371/journal.pgen.1000365
Greliche N, Germain M, Lambert J-C, et al. A genome-wide search for common SNP x SNP interactions on the risk of venous thrombosis. BMC Medical Genetics. 2013;14:36.
Schmutz J et al. (2004). The DNA sequence and comparative analysis of human chromosome 5. Nature, 431(7006), 268-74. https://dx.doi.org/10.1038/nature02919
Lango Allen H, Estrada K, Lettre G, et al. Hundreds of variants clustered in genomic loci and biological pathways affect human height. Nature. 2010;467(7317):832-838.
Rose JE, Behm FM, Drgon T, Johnson C, Uhl GR. Personalized Smoking Cessation: Interactions between Nicotine Dose, Dependence and Quit-Success Genotype Score. Molecular Medicine. 2010;16(7-8):247-253.
Proteins
Genes
Integral membrane proteins | SMIM23 | [
"Chemistry"
] | 1,870 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
64,224,439 | https://en.wikipedia.org/wiki/Negative%20definiteness | In mathematics, negative definiteness is a property of any object to which a bilinear form may be naturally associated, which is negative-definite. See, in particular:
Negative-definite bilinear form
Negative-definite quadratic form
Negative-definite matrix
Negative-definite function
Quadratic forms | Negative definiteness | [
"Mathematics"
] | 61 | [
"Quadratic forms",
"Number theory"
] |
64,224,771 | https://en.wikipedia.org/wiki/SMCHD1 | Structural Maintenance of Chromosomes flexible Hinge Domain Containing 1 (SMCHD1) is a protein that in humans is encoded by the SMCHD1 gene. Mutations in SMCHD1 are causative for development of facioscapulohumeral muscular dystrophy type 2 (FSHD2) and Bosma arhinia microphthalmia syndrome (BAMS).
Without maternal SMCHD1 in the egg cell, children bear with altered skeletal structures.
References
Further reading
External links
PDBe-KB provides an overview of all the structure information available in the PDB for Structural Maintenance of Chromosomes flexible Hinge Domain Containing 1 (SMCHD1)
Human proteins | SMCHD1 | [
"Chemistry"
] | 142 | [
"Biochemistry stubs",
"Protein stubs"
] |
64,227,074 | https://en.wikipedia.org/wiki/Hatice%20Altug | Hatice Altug (; born 1978) is a Turkish physicist and professor in the Bioengineering Department and head of the Bio-nanophotonic Systems laboratory at École Polytechnique Fédérale de Lausanne (EPFL), in Switzerland. Her research focuses on nanophotonics for biosensing and surface enhanced spectroscopy, integration with microfluidics and nanofabrication, to obtain high sensitivity, label-free characterization of biological material. She has developed low-cost biosensor allowing the identification of viruses such as Ebola that can work in difficult settings and therefore particularly useful in case of pandemics.
Altug was the recipient of United States Presidential Early Career Award for Scientists and Engineers and The Optical Society of America Adolph Lomb Medal. She also received European Research Council Consolidator Award, Office of Naval Research Young Investigator Award, National Science Foundation CAREER Award and Popular Science Magazine Brilliant 10 Award. She is a Fellow of the Optical Society of America.
Education
Altug, who was born in Karamanlı district of Burdur in 1978, completed her high school education in 1996 in Antalya Anatolian High School, Antalya, Turkey. She received her B.Sc. degree in physics in 2000 in Bilkent University (Ankara, Turkey), having been awarded a full scholarship there. In 2007, she was awarded a PhD in applied physics from Stanford University (California, U.S.), under the supervision of Professor Jelena Vučković. During her education at Stanford University, she worked on laser systems and optical instruments.
Career
Altug completed a Postdoctoral Fellowship at the Center for Engineering in Medicine at the Harvard Medical School. From 2007 until 2013, she was first an assistant and later an associate professor of Electrical and Computer Engineering at Boston University.
In 2010, she was awarded the Faculty Early Career Development (CAREER) award by the National Science Foundation. Altug disseminated her findings to the public through Boston’s Museum of Science, local educational programs such as Boston Upward Bound Math and Science, and Boston University’s Summer Challenge program on engineering. At the College of Engineering, she added experimental modules to courses relating to nanotechnology. She was also named one of Popular Science’s “Brilliant 10,” a group of researchers under 40 who made transformational contributions to their fields during 2010.
In 2011, IEEE Photonics Society named Altug as winner of the Young Investigator Award, which recognizes individuals who make outstanding technical contributions to the field of photonics prior to their 35th birthday. She was honored for her groundbreaking achievements in confining and manipulating light at the nanoscale to dramatically improve biosensing capabilities.
Altug was recognized with OSA’s Adolph Lomb Medal in 2012 “for breakthrough contributions on integrated optical nano-biosensor and nanospectroscopy technologies based on nanoplasmonics, nanofluidics, and novel nanofabrication.”
She was also named by President Obama among 94 researchers as a recipient of the 2011 Presidential Early Career Awards for Scientists and Engineers (PECASE), the highest honor bestowed by the United States government on science and engineering professionals in the early stages of their independent research careers. As well as attending the White House ceremony, awardees receive a research grant lasting up to five years. She was awarded for leading the development of a biosensor that uses tiny crystals to manipulate light to detect a virus, a protein, or a cancer cell in a drop of blood.
In 2013, Altug joined Ecole Polytechnique Federale de Lausanne, where she became full professor in 2020.
In 2019, she was awarded the ERC Proof of Concept Grant by the European research council for her project: “Portable Infrared Biochemical Sensor Enabled by Pixelated Dielectric Metasurfaces.”
Awards and honors
2021 Fellow of Optica for "pioneering contributions to nano-optics, manipulation of light on-chip, the development of innovative nanobiosensors and sensing techniques, and exemplary contributions to the scientific community and Optica."
2020 European Physical Society Emmy Noether Distinction for Women in Physics
2019 ERC Proof of Concept Grant
2012 Optical Society's Adolph Lomb Medal
2011 Presidential Early Career Awards for Scientists and Engineers
2011 IEEE Photonics Society Young Investigator Award
2010 National Science Foundation Faculty Early Career Development (CAREER) award
References
External links
Fellows of Optica (society)
1978 births
Living people
Women in optics
Optical engineers
Turkish women physicists
Bilkent University alumni
Stanford University alumni
Boston University faculty
Academic staff of the École Polytechnique Fédérale de Lausanne
Metamaterials scientists
Biomedical engineers
Turkish nanotechnologists
People from Burdur Province
Turkish expatriates in the United States
Turkish expatriates in Switzerland
Turkish electrical engineers
Electrical engineering academics
21st-century physicists
Recipients of the Presidential Early Career Award for Scientists and Engineers
21st-century women physicists | Hatice Altug | [
"Materials_science"
] | 994 | [
"Metamaterials scientists",
"Metamaterials"
] |
64,227,325 | https://en.wikipedia.org/wiki/SNAP47 | Synaptosome-associated protein, 47 kDal (SNAP47) is a human protein encoded by the SNAP47 gene. Other aliases of this gene are SVAP1, HEL170, ESFI5812, and HEL-S-290. SNAP47 is a synaptosome protein which is associated with the protein coding in multiple diseases, including non small cell lung cancer and schizophrenia. SNAP47 is a member of the SNAP protein family. SNAP proteins are t-snare proteins that are a component of SNARE complex. The SNARE complex mediates vesicle fusion by creating tight complex that brings vesicle and membrane together. This protein causes ubiquitous expression in testis, ovary, and many other tissues
Gene
The gene is located at 1q42.13, meaning on chromosome 1 on the long arm of the chromosome in region 42, sub region 13. There are a total of 13 exons and 12 introns. This gene spans 52,693 base pairs. It is encoded on the plus strand. The coordinates for this gene are 227728518-227781231. The gene is flanked by ZNF678 gene and PRSS38 gene on the chromosome while the same location on the minus strand JMJD4 gene.
Protein
The most common isoform of SNAP47 is 419 amino acids long. SNAP47 protein is a synaptosome associated protein. Its molecular weight has been found to be 47167 M. SNARE complex (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) includes syntaxin proteins, VAMP proteins and SNAP proteins. SNARE proteins are generally known to be related to vesicle fusion - mediating exocytosis or neurotransmitter release.
They have also been associated with BLOC-1 (biogenesis of lysosome-related organelles complex-1). Hippocampal neurons deficient in BLOC-1 suggest neurite outgrowth defects which when taken with association of SNARE leads to possible variants of genes encoding BLOC-1 - DTNBP1 - in Schizophrenia models.
Secondary structure
The secondary structure of SNAP47 has some long alpha helices intermixed with beta sheet and random coils. The alpha helix are placed at about amino acid 120-150 and amino acids 350-415. SNARE proteins are believed to form compact four-helix complex with membranes. The two alpha helices found are consistent with this observation.
Tertiary structure
I-TASSER assembled and then aligned possible SNAP47 tertiary sequence with 5VOX, a Yeast V-ATPase, and a Ufd2 complexed with ubiquitin-like domain Rad23. The TM scores respectively were 0.917 and 0.584.
Regulation of gene expression
Gene level regulation
Promoter
SNAP47 carries 4 promoter regions that create different variants of transcription. These were identified using by Eldorado at Genomatix. Promoter B boosts transcript variant 2 - GXT_27753855.
Transcription factors
Transcription Factors that have been predicted to attach to the promoter for SNAP47 are SP1, TATAB, and CARF. SP1 or Stimulating protein 1 had a matrix similarity of 1.0 and is a ubiquitous zinc finger transcription factor and is on the minus strand. TATAB is a TATA binding protein factor with a similar matrix of 0.945. CARF is a calcium response element with a matrix similarity of 0.928. SNAP25 decreases Ca2+ responsiveness in GABAargic synapses.
Expression pattern
RNAseq data display SNAP47 to be highly expressed in the adrenal gland, fetal brain, adult brain and the heart. The adrenal gland, hormone producer, was transcribed at 8 reads per kilobase per million (RPKM). The lungs transcription is relatively low transcription except in a 17-week-old fetus. The transcription of the 17-week-old fetus lung is above 2 RPKM. There is low transcription rate (below 2 RPKM) found in the fetal liver, trachea, pancreas and bone marrow. In the cell, SNAP47 localizes cytoplasm, the endoplasmic reticulum (ER), and Vesicular-tubular cluster (ERGIC).
The protein abundance is about average when compared to all the other proteins in humans. However, the mRNA has a higher than average abundance seen in this microarray. The mRNA is at or above the 75th percentile in the microarray for most of the tissues tested. This may suggest that there is a larger expression rate but the protein is used up quickly for its function.
Protein level regulation
Post-transnational modification
SNAP47 had multiple possible post-translational modifications. High conserved phosphorylation sites were predicted at Y15, S129, S262, and S284 - none with specific kinases. Protein Kinase C plays a role in several signal transduction cascades including calcium release. They had had scores of 0.830, 0.747, and 0.812 at S82, S223, and S231 respectively.
Palmitoylation sites are important in anchoring the SNARE complex to the cytosolic side of membranes. Since many SNAP proteins do not have trans-membrane domains, these are common way of attachment. The Palitic acid is covalently attaches to a cysteine residue. Two Palmitoylation sites were predicted at the beginning of SNAP47 protein at Cys6 and Cys12.
Propeptide cleavage site was predicted at R417 while an acetylation was predicted on S2.
Homology and evolution
Orthologs
As of June 2020, SNAP47 is conserved in 310 orthologs. C. lupus, a wolf/dog, has a 74.2% identity. M. mulatta, a monkey, was aligned with the Homo sapiens protein transcript and a 67.1% identical amino acids were found. P. Marinus, a sea lamprey, is the most distant ortholog found at a 36.1% sequence identity. It was conserved in eukaryotes but not bacteria or Archaea. A selected list of orthologs obtained are shown below.
Paralogs
SNAP47 has 3 known paralogs - SNAP23, SNAP25, SNAP 29. The sequence similarity and identity is lower than 30% for all three. This suggest low relationship between different SNAP proteins. SNAP23 and SNAP25 were 55% identical suggesting the relationship between those two paralogs are higher. There is some evidence that if SNAP29 was incapacitated, SNAP47 would be able to take over function of vesicle fusion however, it would not be efficient or successful.
Function/biochemistry
The paralogs, SNAP23 and SNAP25 are t-SNARE proteins, meaning it is present on the presynaptic plasma membrane that is being fused to (the target). These proteins bind to syntaxin protein that attaches to the membrane. SNAP29, however, is binds to syntaxin on vesicles membranes rather than to plasma membranes. SNAP29 has also been found to be membrane bound with a large amount sticking into the cytoplasm.
Interacting proteins
Many interacting proteins are related to vesicle-associated proteins. Some important proteins that interact with the SNAP47 protein are vesicle-associated membrane protein (VAMP) and syntaxin (Stx) which are both used in the SNARE complex. Various paralogs for VAMP and Stx were found as possible interactions. They were experimentally tested using anti-tag coimmunoprecipitation. VAMP4 and Stx-1A interact in the calcium dependent exocytosis. Golgin subfamily A member 2 protein (GOLGA2) is a protein used as a vesicle facilitating vesicle fusion with Golgi apparatus. A microarray as well as prey pooling approach were used to determine this interaction between GOLGA2 and SNAP47. A component of LINC (linker of Nucleoskeleton and cytoskeleton) Complex is the KASH5 protein that was found to interact with SNAP47 by a two hybrid and prey pooling approach.
Clinical significance
Two viruses that interact are rep and PVR proteins which are replicase polyprotein 1ab and Poliovirus receptor respectively. Replicase polyprotein 1ab protein is in the human Sars coronavirus. Rep is involved in the transcription and replication of viral RNAs. An alternative name is the ORF1ab polyprotein. It contains the polyprotein cleavage proteinases. The optimum pH for the proteinase activity is 7.0. Pp1ab is known to be cleaved in 15 different chains including (not limited to) Host translation inhibitor nsp1, 3C-like proteinase, and helicase. Not much is known in how it interacts with SNAP47.
The poliovirus receptor plays a role in cell motility during tumor cell invasion and migration. PVR binds to CD96 and CD226 - Natural killer cell receptors. This can cause PVR to possibly be transferred to NK cells and cause fratricide of Natural killer cells which can increase metastasizing possibilities. Although the lung does not seem to have a large expression of this protein, it has been found that C1orf142 has larger expression rates in cell line of giant cell lung carcinoma they have high metastatic potential. Cell line 95D (high metastatic potential) was studied along with 95C (low metastatic potential) and it is suggested that there is a possible link between SNAP47 protein and metastasis in lung cancers.
References
Proteins | SNAP47 | [
"Chemistry"
] | 2,018 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
64,228,839 | https://en.wikipedia.org/wiki/Stem%20cell%20tourism | Stem cell tourism, a form of medical tourism, is the internet based-industry in which stem cell procedures are advertised to the public as a proven cure. In the majority of cases, it leads to patients and families traveling abroad to obtain procedures that are not proven, nor part of a clinical trial approved by an authority like the Food and Drug Administration in the United States. These procedures have not gone through the vetting process of clinical research and they lack rigorous scientific support. Although for the general public, this advertising in glossy websites, may sound authoritative, for translational doctors and scientists this leads to the exploitation of vulnerable patients. These procedures lack the reproducibility, the rigor that is required for successful development of new effective medications. Although the term may imply traveling overseas, in recent years, there has been an explosion of "stem cell clinics' in the US which has been well documented. These activities are highly profitable for the clinic but no benefit for the patients, sometimes experiencing complications like spinal tumors, death, or financial ruin, all of which are documented in the scientific literature. There is a great deal of interest in educating the public and patients, families and doctors who deal with patients requesting stem cells clinics. In recent years, the FDA has become more active in overseeing stem cell clinics, taking a number of concrete steps including sending warning letters, putting out advisories, and in two cases filing suit in federal court to impose permanent injunctions on specific clinic firms.
Despite the great interest generated in the public for the use of stem cells, among all stem cell scientists, including the International Society for Stem Cell Research, the largest academic organization of scientist and advocates for stem cell research in the world. Stem cell "therapy" is an aspirational goal, is still under development and although there is a great deal of research around the world. Rigorous stem cell trials are still ongoing and patients should be educated to be aware of the unethical clinics in the US or abroad, that offer stem cells procedures as a cure when it is still under investigation.
Furthermore, there is confusion in the general public between the concept of the "right to try" (RTT) legislation to the right to pursue any"stem cell preparations'. These are different concepts. RTT is usually approved for promising pharmacological compounds that have earned a sound scientific or pre-clinical support. In contrast to stem cell tourism infusions that do not. One of the key elements in the RTT is the concept of promising, that is not just a theoretical possibility but a demonstrable and reproducible evidence obtained by scientific experimentation. The right to try legislation seek opportunities for incurables and often terminal patients to receive the compassionate use of experimental therapies that have passed phase I clinical trials that have not gone through all the checks and balances needed for approval. In contrast to the stem cell tourism, these trials have oversight by the FDA and there is no direct financial exploitation for the patient and families.
References
Human subject research
Bioethics | Stem cell tourism | [
"Technology"
] | 611 | [
"Bioethics",
"Ethics of science and technology"
] |
64,229,494 | https://en.wikipedia.org/wiki/Kim%20Dong-man | Kim Dong-man (, born May 11, 1955) is a South Korean food engineer. He is an expert in post-harvest management of fresh produce.
In 1980, he began his career as a researcher in the Food Science Lab of Korea Institute of Science and Technology. His initial field of research was on the storage and distribution of fresh agricultural products. After 1988, he has worked at the Korea Food Research Institute, where he conducted research on processing, packaging, storage, and distribution technologies for fresh agricultural products, and teach technologies both domestically and abroad. He has published 210 research reports, 50 domestic and foreign patents, and 230 research papers individually or jointly. He served as Director of the Korea-ASEAN FTA Cooperation Project, Head of Convergence Technology Research Division of Korea Food Research Institute, Vice Chairman of the Korea Food Storage and Distribution Society, and KOICA advisor.
He learned agricultural distribution technology from GTZ in Germany for rural areas of the Republic of Korea, which was still a developing country in the 1980s. After 1994, with the advance of Korea's food engineering to some extent, he has been carrying out aid projects to improve management of post-harvest fresh agricultural products for technically lagging Southeast Asian countries. The targets include countries such as the Philippines (FDC), Vietnam (NACENTECH), Cambodia (CADRI), Indonesia (PAJAJALAN UNIV.), Myanmar, Azerbaijan, etc. In recognition of his achievements in this project, he was awarded the Plaque of Appreciation and the Merit Medal by the Philippine President and the Vietnamese government, respectively.
Since 2011, he has served as Director of the Korea-ASEAN FTA Cooperation Project, focusing mainly on Myanmar, the poorest member of the ASEAN member countries in terms of Per capita income. Based on KOICA's budget, the Korea Food Research Institute established the “Postharvest Technology Training Centre” to help Myanmar, which has suffered losses of 30-70% after harvesting. Since January 2015, the educational facility has been acquired and operated by the Ministry of Agriculture and Irrigation of Myanmar. Kim Dong-man received the Myanmar Government Citation from Vice President Nian Thun on March 2, 2015, in recognition of his contribution to improving the distribution structure of agricultural products in Myanmar and building a foundation for food engineering technology.
Career
August 1980: Korea Advanced Institute of Science and Technology (KIST) Food Engineering Lab. (Senior Researcher)
June 1982: German Federal Institute for Nutrition (Karlsluhe, visiting researcher)
May 1988: Korea Food Research Institute (Responsible Researcher)
September 1995: Korea-Philippines, Korea-Vietnam Agricultural Products Distribution Technology Development Research Director
October 1997: Korean Commissioner of ATC in APEC (Food Processing, Storage, Distribution)
October 2000: Head of Planning and Coordination Division, Korea Food Research Institute
May 2002: Head of Korea-ASEAN post-harvest management technology cooperation project
May 2006: Head of Korea-Azerbaijan Agricultural Products Distribution Technology Cooperation Project
November 2007: Head of Korea-Cambodia/Myanmar Distribution Technology Cooperation Project
January 2008: Head of Korea-ASEAN FTA Agricultural Products Distribution Technology Cooperation Project
September 2011: Head of Convergence Technology Research Division, Korea Food Research Institute
September 2011: Head of KOICA Myanmar agricultural products post-harvest management technology cooperation project
Education
February 1978: Graduated from Department of Food Science and Technology, College of Agriculture, Chungnam National University (Bachelor of Agriculture)
August 1980: Graduated from Chungnam National University, Department of Food Engineering (Master of Agriculture)
August 1987: Graduated from the Department of Food Science and Technology, Graduate School of Dongguk University (Doctor of Engineering)
October 1992: Completion of post-doc course, Department of Food Science and Technology, Cornell University, USA
Award
June 2002: Appreciation Plaque for Technology Transfer, President of the Philippines
November 2003: Excellence Research Award, President of the Republic of Korea
December 2007: Medal of Merit for Science and Technology, Government of Vietnam
March 2015: Commendation for distribution of agricultural products, Government of Myanmar
References
Living people
Food engineers
Dongguk University alumni
South Korean scientists
1955 births | Kim Dong-man | [
"Engineering"
] | 818 | [
"Food engineers",
"Food engineering"
] |
64,230,048 | https://en.wikipedia.org/wiki/Epistemic%20innocence | Epistemic innocence is a psychological phenomenon that applies to epistemically costly and epistemically beneficial cognition. It determines the relationship between a cognition's psychological and epistemic benefits.
Definition
It is defined as the epistemic status of faulty cognition that have epistemic costs as well as epistemic benefits.
Description
A cognition that has an epistemic cost can also have an epistemic benefit that would have been unattainable with low epistemically costly means in epistemically innocent. Unrealistically optimistic beliefs, confabulatory explanations, delusions including motivated delusions, delusions in schizophrenia, delusions in depression, and inaccurate social cognition are examples of epistemic innocence. It does not fall into the category of epistemic goodness.
The framework determines the relationship between a cognition's psychological and epistemic benefits. These cognition can also be used to oppose views on delusion formation. The notion of epistemic is that false or irrational beliefs can be used despite failing to achieve accuracy or justification. It also contributes to a better understanding of a critical aspect of one's cognitive and epistemic lives.
The epistemic innocent cognition fill an explanatory gap that cannot be filled in any other condition. It maintains consistency between different beliefs of a subject and leads to acquisition and retention of true beliefs.
Conditions
Two conditions make a cognition epistemic innocent; epistemic benefit and no alternatives. The first condition, epistemic benefit, governs a situation where the memory supports significant epistemic benefit to an agent. The second condition is when a less distorted memory when a epistemic benefit is not available.
Epistemic benefit
It includes the maximizing of the acquisition and retention of true beliefs, promotion of intellectual virtues, or avoiding epistemic blame.
No alternatives
It is a condition where there is no alternative to adopting a delusional belief due to the unavailability of supporting evidence. The unavailability can be of three types strictly unavailable, motivationally unavailable, or explanatorily unavailable.
References
Psychological concepts
Cognitive psychology | Epistemic innocence | [
"Biology"
] | 435 | [
"Behavioural sciences",
"Behavior",
"Cognitive psychology"
] |
64,230,622 | https://en.wikipedia.org/wiki/Cyclobutanol | Cyclobutanol is an organic compound with the chemical formula C4H8O; it is defined as a cyclobutyl group with a hydroxyl group pendant and thus a cycloalkanol. Physically, it is a yellowish clear liquid that crystallizes orthorhombically at low-temperatures.
Cyclobutylamine's Demjanov rearrangement with nitrous acid gives cyclobutanol, and cyclopropylmethanol rearranges in strong acid to the same. Metal hydrides reduce cyclobutanone to cyclobutanol; conversely, cyclobutanol oxidation is a salt-free route to cyclobutanone.
References
Cycloalkanols
Cyclobutyl compounds | Cyclobutanol | [
"Chemistry"
] | 174 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
64,236,449 | https://en.wikipedia.org/wiki/Leopoldo%20Pando%20Zayas | Leopoldo A. Pando Zayas is a physicist and string theorist. He is professor in the Department of Physics at the University of Michigan, Ann Arbor.
Education and career
Leopoldo Avelino Pando Zayas grew up in Cuba. In 1989, when he was a high school student, he won the Silver Medal in the International Physics Olympiad, which took place that year in Warsaw, Poland.
Pando Zayas received his M.S. degree in physics in 1995, and his PhD in 1998, both from Moscow State University in Russia. He has held visiting appointments at the Institute for Advanced Study in Princeton, New Jersey; the Kavli Institute for Theoretical Physics at the University of California, Santa Barbara; and, as a staff associate, at the Abdus Salam International Center for Theoretical Physics (ICTP) in Trieste, Italy.
Research and publications
Pando Zayas specializes in string theory with a focus on quantum gravity. He has published many articles on the gauge/gravity correspondence and has applied these techniques to the study of the dynamics of superconductors and strongly interacting fluids. His work has also elucidated the microscopic origin of the thermodynamics of black holes.
Pando Zayas translated a two-volume textbook on applications and methods in modern geometry, by B.A. Dubrovin, A.T. Fomenko, and S.P. Nóvikov, from Russian into Spanish. This book appeared as Geometría moderna: métodos y aplicationes (Moscow, 2000).
References
Living people
Theoretical physicists
String theorists
University of Michigan faculty
Moscow State University alumni
Cuban people of African descent
21st-century Cuban scientists
1970 births
Cuban emigrants to the United States | Leopoldo Pando Zayas | [
"Physics"
] | 352 | [
"Theoretical physics",
"Theoretical physicists"
] |
64,236,931 | https://en.wikipedia.org/wiki/MIF4GD | MIF4GD, or MIF4G domain-containing protein, is a protein which in humans is encoded by the MIF4GD gene. It is also known as SLIP1, SLBP (Stem-Loop Binding Protein)-interacting protein 1, AD023, and MIFD. MIF4GD is expressed ubiquitously in humans, and has been found to be involved in activating proteins for histone mRNA translation, alternative splicing and translation of mRNAs, and is a factor in the regulation of cell proliferation.
Gene
The MIF4GD gene is located in humans on the minus strand of chromosome 17q25.1, and spans 5.0 Kb, from bases 75,266,228 to 75,271,292.
mRNA
There are 11 alternatively-spliced mRNA transcripts and 3 unspliced mRNA transcripts that can be transcribed from this gene, which include 7 possible exons and 11 distinct introns.
Protein
There are 10 viable isoforms of the MIF4G domain-containing protein. The longest isoform is MIF4G domain-containing protein isoform 1, which is 263 amino acids long, however, the most common isoform is MIF4G domain-containing protein isoform 4, which consists of 6 exons and is 222 amino acids in length.
Features
MIF4G domain-containing protein isoform 1 has a predicted molecular weight of 30.1 kDa, and a predicted isoelectric point of 5.2, indicating that it is an acidic protein. It has a normal ratio of each amino acid when compared to the average human protein. Additionally, MIF4GD is expected to form 11 alpha helices.
Sub-cellular localization
Searches of MIF4GD antibodies showed that MIF4GD is present in the cytoplasm and nucleoli of cells. Additionally, several bioinformatic programs predict human MIF4GD, as well as several of its orthologs, are present in the cytoplasm, nucleus and mitochondria of cells.
Post-translational modifications
Due to its presumed localization in the cytoplasm, it is predicted that MIF4GD could be phosphorylated, acetylated, ubiquitinated, or sumoylated. Additionally, MIF4GD is predicted to contain a "YinOYang" site at S61, which may be either O-GlcNAcylated or phosphorylated at different times for regulatory purposes. It is not likely that the MIF4GD protein will be lipid-linked or glycosylated.
MIF4G domain
The MIF4GD protein that contains an MIF4G domain, which is named after the middle domain of eukaryotic initiation factor 4G (eIF4G).
The MIF4G domain of the MIF4GD protein has a molecular weight of 17.0 kDa, and has a predicted isoelectric point of 5.7. Similar to the entire protein, it contains normal ratios of each amino acid relative to a reference of human proteins, however, it contains less negatively-charged amino acids and more positively-charged amino acids relative to the entire protein. The MIF4G domain is predicted to contain many alpha-helices and is thought to contain alpha-helical repeats.
Expression and regulation
MIF4GD is found only in animals, and is expressed ubiquitously in the body, though it has been discovered to be expressed at a somewhat higher rate in lymph nodes, bone marrow and testes. MIF4GD is expressed at an average rate that is 1.7 times higher than the average gene.
The promoter region of MIF4GD is approximately 1137 nucleotide base pairs long, and is predicted to interact with various transcription factors. The 5' untranslated region of MIF4GD mRNA transcripts is relatively short, at a length of around 137 nucleotides, and is predicted to form stem-loops and interior-loops to which RNA-binding proteins may bind. The 3' untranslated region is longer, at a length of approximately 510 nucleotides. The 3' UTR is also predicted to form stem-loops, interior-loops, and bulge-loops, as well as more complex secondary structures, and is predicted to bind to RNA-binding proteins and miRNAs at or near these sites.
Interactants
MIF4GD has been experimentally shown to bind to various other proteins, many of which play a role in alternative splicing of pre-mRNAs and translation of mRNAs into proteins. It also is known to interact with eukaryotic translation initiation factors, RNA, and DNA to form a translation initiation complex. Some of the most notable proteins that interact with MIF4GD are:
ATP-dependent RNA helicases DDX19A and DDX19B, which is involved in mRNA export from the nucleus and helicase activity by facilitating the disassociation of nuclear mRNA binding proteins and replacement with cytoplasmic mRNA binding proteins.
Cap binding complex dependent translation initiation factor, or CTIF, which is a paralog of MIF4GD. CTIF binds cotranscriptionally to the cap end of the nascent mRNA, and is involved in simultaneous editing and translation of mRNA that happens directly after export from the nucleus.
Histone RNA hairpin-binding protein, or SLBP, which is involved in histone pre-mRNA processing and movement of mRNAs from the nucleus to the cytoplasm of cells.
Supervillin, or SVIL, which is a peripheral membrane protein that forms a high-affinity link between the actin cytoskeleton and the membrane and contributes to myogenic membrane structure and differentiation. Supervillin also regulates cell spreading and motility during the cell cycle.
MIF4GD also has been verified by two-hybrid bait-prey experiments to interact with NSP7ab, or Non-structural protein 7, of SARS-CoV.
Function and clinical significance
MIF4GD has several known functions, including the activation of proteins that bind histone mRNAs for translation and binding of mRNAs for alternative splicing and translation into proteins. Additionally, down-regulation of the SLIP1/MIF4GD gene and corresponding protein results in a reduced rate of histone mRNA translation and reduced cell viability. Therefore, it is speculated to be needed in eukaryotic cells in order to produce proteins and for cell proliferation.
MIF4GD has been shown to bind and stabilize p27kip1, which plays an important role in the regulating the cell cycle and in cancer progression. When bound to MIF4GD, the stabilized protein suppresses phosphorylation by CDK2 at T187, which controls the amount of cell proliferation in hepatocellular carcinoma (HCC). Regulation of this interaction is being studied as a potential therapeutic treatment for patients with hepatocellular carcinoma. This provides more evidence that MIF4GD helps regulate cell proliferation, and suggests MIF4GD may play a role in immune response.
Sequence homology and evolutionary history
MIF4GD is found in Animalia, and first appeared in Porifera, which diverged from Homo sapiens around 777 million years ago. Relative to humans, this gene is highly conserved (>80% identity and >90% similarity) in mammals and reptiles, moderately conserved (>70% identity and >85% similarity) in chordates, and low levels of conservation (15-25% identity and 25-40% similarity) to the rest of Animalia. MIF4GD is not present in trichoplax, fungi, plants, protists, archaea or bacteria.
Orthologs
There are currently 310 known and sequenced MIF4GD orthologs found in Animalia. A select number of these orthologs have been analyzed for estimated time of divergence (in millions of years), amino acid sequence identity to humans, and amino acid sequence similarity to humans. The results are shown in the table below:
Paralogs
MIF4GD has two known paralogs, which are PAIP1 and CTIF. Both known paralogs have moderate to low conservation to MIF4GD, with less than 15% identity and between 20 and 25% similarity. However, both of these genes are predicted to have diverged before the evolution of orthologs, and scored E-values of nearly zero, indicating a significant relationship with MIF4GD.
MIF4GD is a slowly-evolving gene, with an approximate average of 75 amino acid changes per hundred amino acids per million years. Multiple sequence alignments of human MIF4GD and its orthologs showed two conserved amino acids throughout all sequences, which are Gly200 and Glu241.
References
Proteins | MIF4GD | [
"Chemistry"
] | 1,884 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
64,236,977 | https://en.wikipedia.org/wiki/Ecotron | An Ecotron is an experimental instrument in ecology consisting of a controlled environment which makes it possible to simultaneously condition the environment of natural, simplified, or completely artificial ecosystems and measure the processes generated by living beings present in these ecosystems, in particular the flow of matter and energy.
Design
Its principle is to confine ecosystems in totally or partially waterproof enclosures which are permeable to energy flow and capable of generating a range of physical and chemical conditions applied to terrestrial or aquatic ecosystems, continental or marine. Environmental control and real-time measurements are precise enough to test hypotheses or operating models. For this purpose, the enclosures are fitted with significant equipment allowing continuous measurement of fluxes, states or biological characteristics. Other specific measurements, in situ and ex situ, on samples taken complete these online measurements. A sufficient number of independent confinement chambers is necessary to study several interacting factors in a framework of statistical inference.
Depending on the case, we speak of a macrocosm when the space is large enough to study several m3 of reconstituted ecosystem over a period of time, generally measured in years (3-5 years or more for example), of microcosm for volumes measuring in cubic decimeters (study of fungal, bacterial, soil ecosystems, etc.) and mesocosm for intermediate situations.
References
Bibliography
Lawton, J. H., Naeem, S., Woodfin, R. M., Brown, V. K., Gange, A., Godfray, H. J. C., Heads, P. A., Lawler, S., Magda, D., Thomas, C. D., Thompson, L. J. & Young, S. (1993) "The Ecotron - a Controlled Environmental Facility for the Investigation of Population and Ecosystem Processes." Phil. Trans. R. Soc. B, 341, 181-194.
Lawton, J. H. (1996) "The Ecotron facility at Silwood Park: The value of big bottle" experiments. Ecology, 77, 665-669.
Loreau, M. (1998) Biodiversité et fonctionnement des écosystèmes n°81, pp. 3-7. French National Centre for Scientific Research, Paris.
External links
Paris CEREEP – ECOTRON IDF
Montpellier European Ecotron
Ecosystems
Scientific instruments | Ecotron | [
"Technology",
"Engineering",
"Biology"
] | 486 | [
"Scientific instruments",
"Symbiosis",
"Ecosystems",
"Measuring instruments"
] |
42,837,588 | https://en.wikipedia.org/wiki/Eta2%20Pictoris | {{DISPLAYTITLE:Eta2 Pictoris}}
η2 Pictoris, Latinised as Eta2 Pictoris, is a solitary star in the southern constellation of Pictor. It is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.02. With an annual parallax shift of as seen from the Earth, it is located around 418 light years from the Sun. It is a member of the HR 1614 moving group of stars that share a common motion through space.
This is an evolved K-type giant star with a stellar classification of K5 III, having exhausted the supply of hydrogen at its core, then cooled and expanded off the main sequence. At present it has 41 times the girth of the Sun. It is radiating an estimated 363.5 times the Sun's luminosity from its photosphere at an effective temperature of 4,136 K. This is a member of the old disk population and is a suspected variable star.
References
K-type giants
Suspected variables
Pictor
Pictoris, Eta2
Durchmusterung objects
033042
023649
1663 | Eta2 Pictoris | [
"Astronomy"
] | 241 | [
"Pictor",
"Constellations"
] |
42,837,614 | https://en.wikipedia.org/wiki/Eta1%20Pictoris | {{DISPLAYTITLE:Eta1 Pictoris}}
η1 Pictoris, Latinised as Eta1 Pictoris, is a solitary star in the southern constellation of Pictor. It is faintly visible to the naked eye with an apparent visual magnitude of +5.37. Based upon an annual parallax shift of 38.35 mas as seen from the Earth, the system is located 85 light years from the Sun. The star made its closest approach to the Sun about 1.1 million years ago with a perihelion passage of about .
This is an F-type main sequence star with a stellar classification of F5 V and it is chromospherically active. It is an estimated 2.15 billion years old and is spinning with a projected rotational velocity of 22.7 km/s. The star has 1.4 times the mass of the Sun and about 1.1 times the Sun's radius. It is radiating 3.7 times the Sun's luminosity from its photosphere at an effective temperature of roughly 6,631 K.
References
F-type main-sequence stars
Pictor
Pictoris, Eta1
Durchmusterung objects
032743
023482
1649
0187 | Eta1 Pictoris | [
"Astronomy"
] | 258 | [
"Pictor",
"Constellations"
] |
42,838,821 | https://en.wikipedia.org/wiki/Mu%20Pictoris | μ Pictoris, Latinised as Mu Pictoris, is a binary star system in the southern constellation Pictor. It is bright enough to be dimly visible to the naked eye, having a combined apparent visual magnitude of 5.69. Based upon an annual parallax shift of 4.31 mas as seen from Earth, the system is located roughly 760 light years distant from the Sun. As of 2010, the pair have an angular separation of 2.46 arc seconds along a position angle of 221°.
The primary, designated component A, is a blue-white star with a visual magnitude of 5.71 and a stellar classification of B9 Ve or B9 IVn. The first classification suggests is a B-type main-sequence star, with the 'e' suffix indicating a Be star. The second may instead indicate a somewhat more evolved B-type star that is spinning rapidly, resulting in "nebulous" absorption lines. Photometrically, it shows a pulsation period of 0.397 days, which is likely the same as the rotation period.
The secondary companion, component B, is a white-hued star of magnitude 9.43 with a classification of A8 V:p?. This indicates it is an A-type main-sequence star, with the 'p?' suffix suggesting it may be chemically peculiar while the ':' notation says there is some uncertainty about the general classification.
References
B-type subgiants
B-type main-sequence stars
A-type main-sequence stars
Binary stars
Pictor
Pictoris, Mu
046860
031137
2412
Durchmusterung objects | Mu Pictoris | [
"Astronomy"
] | 340 | [
"Pictor",
"Constellations"
] |
42,838,852 | https://en.wikipedia.org/wiki/R%20Pictoris | R Pictoris is a semiregular variable type star in the constellation Pictor. It ranges between apparent magnitude 5.1 and 14.4, and spectral types M1IIe to M4IIe, over a period of 168 days. It should be faintly visible to the naked eye of an observer with excellent observing conditions, when it is near its maximum brightness.
In 1895, Williamina Fleming discovered that the star is a variable star. In 1907 it appeared with its variable star designation, R Pictoris, in Annie Jump Cannon's Second Catalog of Variable Stars.
References
Durchmusterung objects
030551
022170
Pictoris, R
Pictor
M-type giants
Semiregular variable stars | R Pictoris | [
"Astronomy"
] | 151 | [
"Pictor",
"Constellations"
] |
42,840,327 | https://en.wikipedia.org/wiki/Jean-Claude%20Bradley | Jean-Claude Bradley was a chemist who actively promoted Open Science in chemistry, including at the White House, for which he was awarded the Blue Obelisk award in 2007. He coined the term "Open Notebook science". He died in May 2014. A memorial symposium was held July 14, 2014 at Cambridge University, UK.
One outcome of his Open Notebook work is the collection of physicochemical properties of organic compounds he was studying. All of this data he made available as Open data under the CCZero license. For example, in 2009 Bradley et al. published their work on making solubility data of organic compounds available as Open data. Later, the melting point data set he collaborated on with Andrew Lang and Antony Williams was published with Figshare. Both data sets were also made available as books via the Lulu.com self-publishing platform.
He blogged extensively and contributed to at least 25 individual blogs. In an interview in 2008 with Bora Zivkovic titled "Doing Science Publicly", he spoke of his work and online presence. In 2010, he gave an extensive interview about the impact of Open Notebook science with Richard Poynder.
References
External links
Jean-Claude Bradley's Google Scholar Citations Page
Jean-Claude Bradley's YouTube Channel
Jean-Claude Bradley's FriendFeed entries
In Memoriam JCB Memorial wiki (archived version)
Organic chemists
Open science
Open content activists
2014 deaths
Year of birth missing | Jean-Claude Bradley | [
"Chemistry"
] | 294 | [
"Organic chemists"
] |
42,840,382 | https://en.wikipedia.org/wiki/SYSACCO | SYSACCO is a Syrian-Saudi Chemical Company with headquarter in Aleppo, Syria. Their chemical plant with an area of 142,000 m2 is located east of Aleppo. SYSACCO is Syria’s only chlorine manufacturing plant.
Products
They mostly produce products for water sterilization to the local market:
Sodium hydroxide, also known as Caustic Soda.
Chlorine gas cylinders.
Sodium hypochlorite, the sodium salt of hypochlorous acid.
Hydrochloric Acid, a clear, colorless, highly pungent solution of hydrogen chloride in water.
References
External links
www.sysacco.net
Chemical plants | SYSACCO | [
"Chemistry"
] | 137 | [
"Chemical process engineering",
"Chemical plants"
] |
42,840,384 | https://en.wikipedia.org/wiki/Linearizer | In signal processing, linearizers are electronic circuits which improve the non-linear behaviour of amplifiers to increase efficiency and maximum output power.
Creating circuits with the inverted behaviour to the amplifier is one way to implement this concept. These circuits counteract the non-linearities of the amplifier and minimize the distortion of the signal. This increases linear operating range up to the saturation (maximum output power) of the amplifier. Linearized amplifiers have a significantly higher efficiency with improved signal quality. There are different concepts to linearize an amplifier, including pre- and post-distortion and feedback linearization. Most commonly used is pre-distortion linearization.
The function performed by the linearizer in relation to the amplifier is very similar to that of eyeglasses in relation to the eye. The eye distorts the image seen; the glasses pre-distort the image. When these two distortions are combined, the result is a clear image. For the nearsighted, the glasses must pre-distort the image one way. For the farsighted, the image must be pre-distorted in the opposite way.
Functionality of Pre-distortion Linearizers
Non-linearities occur in amplifiers due to decreasing amplification and changing phase when operated near saturation. This behavior is commonly referred to as gain or phase compression. The pre-distortion linearizer is designed to compensate these changes. The resulting behavior is commonly referred to as gain or phase expansion.
A pre-distortion linearizer works by creating signal distortion (amplitude and phase) that is the complement of the signal distortion inherent in the High-Powered Amplifier. The signal to be amplified is first passed through the linearizer, distorting the signal, with no loss in gain. The distorted signal is then fed to the High-Powered Amplifier to be amplified. The distortion inherent in the High-Powered Amplifier negates the distortion introduced by the linearizer producing a near linear transfer characteristic.
Figure 1 shows the amplification (gain) contingent upon input power. The gain compression of the amplifier starts above a certain input power level (red curve).
By adding a pre-distortion linearizer (blue curve) in front of the amplifier, the gain compression effect is compensated up to a certain power level (green curve). The point where the gain of the total system is starting to drop off is pushed to a higher power level thereby increasing the linear operating range. In practice, the linear output power level of an amplifier increases significantly (up to four times).
The increased linear operating range is also illustrated in Figure 2 (light blue area). The chart shows the relationship between input and output power of an amplifier with and without pre-distortion linearizer. The dotted line shows the output power of the amplifier as a function of the input power on a logarithmic scale. In this illustration the compression is shown as the deviation from the ideal 45° line. The amplifier with pre-distortion linearizer (solid line) deviates from the ideal line at a much higher power level. The light blue area illustrates the improved linear operating power range gained by adding a pre-distortion linearizer.
Advantages of Pre-distortion Linearizers
Pre-distortion linearizers operate in the small signal area and increase the DC power consumption of the system only marginally. Additional advantages can be deduced including:
Small foot print, low weight.
Low cost solution compared to use of higher power amplifier in similar linear operating range.
Lower environmental impact through improved efficiency.
Retrofit possible
Adjustment to different amplifier types possible
Highly reliable
Typical Properties of a Pre-distortion Linearizer
Dimensions: Dependent on design in the range of a few cm
Weight: 20g to 200g depending on features
Frequencies: 1 to 50 GHz with different bandwidths
Expansion levels:
Gain: up to 10 dB, dependent on amplifier data
Phase: up to 60°
Applications
The preferred application of linearizers is in high power amplifiers using electron tubes (traveling wave tubes, Klystron tubes, magnetron tubes) or solid state amplifiers (GaN, GaAs, Si). These systems are used in broadband voice and data transfer applications including Satellite Communication, Broadband Internet, or HD/3D television. These applications require high signal quality. The optimization of the amplifier characteristics enables the ideal use of available power and leads to energy savings of up to 50%.
References
External links
http://www.astyx.net/en/satellitenkommunikation/linearisierer.html
Electronic amplifiers
Electronic circuits | Linearizer | [
"Technology",
"Engineering"
] | 915 | [
"Electronic engineering",
"Electronic amplifiers",
"Amplifiers",
"Electronic circuits"
] |
42,841,555 | https://en.wikipedia.org/wiki/De%20materia%20medica | (Latin name for the Greek work , , both meaning "On Medical Material") is a pharmacopoeia of medicinal plants and the medicines that can be obtained from them. The five-volume work was written between 50 and 70 CE by Pedanius Dioscorides, a Greek physician in the Roman army. It was widely read for more than 1,500 years until supplanted by revised herbals in the Renaissance, making it one of the longest-lasting of all natural history and pharmacology books.
The work describes many drugs known to be effective, including aconite, aloes, colocynth, colchicum, henbane, opium and squill. In total, about 600 plants are covered, along with some animals and mineral substances, and around 1000 medicines made from them.
was circulated as illustrated manuscripts, copied by hand, in Greek, Latin, and Arabic throughout the medieval period. From the 16th century onwards, Dioscorides' text was translated into Italian, German, Spanish, French, and into English in 1655. It served as the foundation for herbals in these languages by figures such as Leonhart Fuchs, Valerius Cordus, Lobelius, Rembert Dodoens, Carolus Clusius, John Gerard, and William Turner. Over time, these herbals incorporated increasing numbers of direct observations, gradually supplementing and eventually supplanting the classical text.
Several manuscripts and early printed versions of survive, including the illustrated Vienna Dioscurides manuscript written in the original Greek in 6th-century Constantinople; it was used there by the Byzantines as a hospital text for just over a thousand years. Sir Arthur Hill saw a monk on Mount Athos still using a copy of Dioscorides to identify plants in 1934.
Book
Between 50 and 70 AD, a Greek physician in the Roman army, Dioscorides, wrote a five-volume book in his native Greek, (, "On Medical Material"), known more widely in Western Europe by its Latin title . He had studied pharmacology at Tarsus in Roman Anatolia (now Turkey). The book became the principal reference work on pharmacology across Europe and the Middle East for over 1,500 years, and was thus the precursor of all modern pharmacopoeias.
In contrast to many classical authors, was not "rediscovered" in the Renaissance, because it never left circulation; indeed, Dioscorides' text eclipsed the Hippocratic Corpus. In the medieval period, was circulated in Latin, Greek, and Arabic. In the Renaissance from 1478 onwards, it was printed in Italian, German, Spanish, and French as well. In 1655, John Goodyer made an English translation from a printed version, probably not corrected from the Greek.
While being reproduced in manuscript form through the centuries, the text was often supplemented with commentary and minor additions from Arabic and Indian sources. Several illustrated manuscripts of survive. The most famous is the lavishly illustrated Vienna Dioscurides (the Juliana Anicia Codex), written in the original Greek in Byzantine Constantinople in 512/513 AD; its illustrations are sufficiently accurate to permit identification, something not possible with later medieval drawings of plants; some of them may be copied from a lost volume owned by Juliana Anicia's great-grandfather, Theodosius II, in the early 5th century. The Naples Dioscurides and Morgan Dioscurides are somewhat later Byzantine manuscripts in Greek, while other Greek manuscripts survive today in the monasteries of Mount Athos. Densely-illustrated Arabic copies survive from the 12th and 13th centuries. The result is a complex set of relationships between manuscripts, involving translation, copying errors, additions of text and illustrations, deletions, reworkings, and a combination of copying from one manuscript and correction from another.
is the prime historical source of information about the medicines used by the Greeks, Romans, and other cultures of antiquity. The work also records the Dacian names for some plants, which otherwise would have been lost. The work presents about 600 medicinal plants in all, along with some animals and mineral substances, and around 1,000 medicines made from these sources. Botanists have not always found Dioscorides' plants easy to identify from his short descriptions, partly because he had naturally described plants and animals from southeastern Europe, whereas by the 16th century his book was in use all over Europe and across the Islamic world. This meant that people attempted to force a match between the plants they knew and those described by Dioscorides, leading to what could be catastrophic results.
Approach
Each entry gives a substantial amount of detail on the plant or substance in question, concentrating on medicinal uses but giving such mention of other uses (such as culinary) and help with recognition as considered necessary. For example, on the "Mekon Agrios and Mekon Emeros", the opium poppy and related species, Dioscorides states that the seed of one is made into bread: it has "a somewhat long little head and white seed", while another "has a head bending down" and a third is "more wild, more medicinal and longer than these, with a head somewhat long—and they are all cooling." After this brief description, he moves at once into pharmacology, saying that they cause sleep; other uses are to treat inflammation and erysipela, and if boiled with honey to make a cough mixture. The account thus combines recognition, pharmacological effect, and guidance on drug preparation. Its effects are summarized, accompanied by a caution:
Dioscorides then describes how to tell a good from a counterfeit preparation. He mentions the recommendations of other physicians, Diagoras (according to Eristratus), Andreas, and Mnesidemus, only to dismiss them as false and not borne out by experience. He ends with a description of how the liquid is gathered from poppy plants, and lists names used for it: chamaesyce, mecon rhoeas, oxytonon; papaver to the Romans, and wanti to the Egyptians.
As late as in the Tudor and Stuart periods in Britain, herbals often still classified plants in the same way as Dioscorides and other classical authors, not by their structure or apparent relatedness but by how they smelt and tasted, whether they were edible, and what medicinal uses they had. Only when European botanists like Matthias de l'Obel, Andrea Cesalpino and Augustus Quirinus Rivinus (Bachmann) had done their best to match plants they knew to those listed in Dioscorides did they go further and create new classification systems based on similarity of parts, whether leaves, fruits, or flowers.
Contents
The book is divided into five volumes. Dioscorides organized the substances by certain similarities, such as their being aromatic, or vines; these divisions do not correspond to any modern classification. In David Sutton's view the grouping is by the type of effect on the human body.
Volume I: Aromatics
Volume I covers aromatic oils, the plants that provide them, and ointments made from them. They include what are probably cardamom, nard, valerian, cassia or senna, cinnamon, balm of Gilead, hops, mastic, turpentine, pine resin, bitumen, heather, quince, apple, peach, apricot, lemon, pear, medlar, plum and many others.
Volume II: Animals to herbs
Volume II covers an assortment of topics: animals including sea creatures such as sea urchin, seahorse, whelk, mussel, crab, scorpion, electric ray, viper, cuttlefish and many others; dairy produce; cereals; vegetables such as sea kale, beetroot, asparagus; and sharp herbs such as garlic, leek, onion, caper and mustard.
Volume III: Roots, seeds and herbs
Volume III covers roots, seeds and herbs. These include plants that may be rhubarb, gentian, liquorice, caraway, cumin, parsley, lovage, fennel and many others.
Volume IV: Roots and herbs, continued
Volume IV describes further roots and herbs not covered in Volume III. These include herbs that may be betony, Solomon's seal, clematis, horsetail, daffodil and many others.
Volume V: Vines, wines and minerals
Volume V covers the grapevine, wine made from it, grapes and raisins; but also strong medicinal potions made by boiling many other plants including mandrake, hellebore, and various metal compounds, such as what may be zinc oxide, verdigris and iron oxide.
Influence and effectiveness
In Europe
Writing in The Great Naturalists, the historian of science David Sutton describes as "one of the most enduring works of natural history ever written" and that "it formed the basis for Western knowledge of medicines for the next 1,500 years."
The historian of science Marie Boas writes that herbalists depended entirely on Dioscorides and Theophrastus until the 16th century, when they finally realized they could work on their own. She notes also that herbals by different authors, such as Leonhart Fuchs, Valerius Cordus, Lobelius, Rembert Dodoens, Carolus Clusius, John Gerard and William Turner, were dominated by Dioscorides, his influence only gradually weakening as the 16th-century herbalists "learned to add and substitute their own observations".
Early science and medicine historian Paula Findlen, writing in the Cambridge History of Science: Early Modern Science, calls "one of the most successful and enduring herbals of antiquity, [which] emphasized the importance of understanding the natural world in light of its medicinal efficiency", in contrast to Pliny's Natural History (which emphasized the wonders of nature) or the natural history studies of Aristotle and Theophrastus (which emphasized the causes of natural phenomena). Medicine historian Vivian Nutton, in Ancient Medicine, writes that Dioscorides's "five books in Greek On Materia medica attained canonical status in Late Antiquity." Science historian Brian Ogilvie calls Dioscorides "the greatest ancient herbalist", and "the summa of ancient descriptive botany", observing that its success was such that few other books in his domain have survived from classical times. Further, his approach matched the Renaissance liking for detailed description, unlike the philosophical search for essential nature (as in Theophrastus's ). A critical moment was the decision by Niccolò Leoniceno and others to use Dioscorides "as the model of the careful naturalist—and his book as the model for natural history."
The Dioscorides translator and editor Tess Anne Osbaldeston notes that "For almost two millennia Dioscorides was regarded as the ultimate authority on plants and medicine", and that he "achieved overwhelming commendation and approval because his writings addressed the many ills of mankind most usefully." To illustrate this, she states that "Dioscorides describes many valuable drugs including aconite, aloes, bitter apple, colchicum, henbane, and squill". The work mentions the painkillers willow (leading ultimately to aspirin, she writes), autumn crocus and opium, which however is also narcotic. Many other substances that Dioscorides describes remain in modern pharmacopoeias as "minor drugs, diluents, flavouring agents, and emollients ... [such as] ammoniacum, anise, cardamoms, catechu, cinnamon, colocynth, coriander, crocus, dill, fennel, galbanum, gentian, hemlock, hyoscyamus, lavender, linseed, mastic, male fern, marjoram, marshmallow, mezereon, mustard, myrrh, orris (iris), oak galls, olive oil, pennyroyal, pepper, peppermint, poppy, psyllium, rhubarb, rosemary, rue, saffron, sesame, squirting cucumber (elaterium), starch, stavesacre (delphinium), storax, stramonium, sugar, terebinth, thyme, white hellebore, white horehound, and couch grass—the last still used as a demulcent diuretic." She notes that medicines such as wormwood, juniper, ginger, and calamine also remain in use, while "Chinese and Indian physicians continue to use liquorice". She observes that the many drugs listed to reduce the spleen may be explained by the frequency of malaria in his time. Dioscorides lists drugs for women to cause abortion and to treat urinary tract infection; palliatives for toothache, such as colocynth, and others for intestinal pains; and treatments for skin and eye diseases. As well as these useful substances, she observes that "A few superstitious practices are recorded in ," such as using Echium as an amulet to ward off snakes, or Polemonia (Jacob's ladder) for scorpion stings.
In the view of the historian Paula De Vos, formed the core of the European pharmacopoeia until the end of the 19th century, suggesting that "the timelessness of Dioscorides' work resulted from an empirical tradition based on trial and error; that it worked for generation after generation despite social and cultural changes and changes in medical theory".
At Mount Athos in northern Greece Dioscorides's text was still in use in its original Greek into the 20th century, as observed in 1934 by Sir Arthur Hill, Director of the Royal Botanic Gardens, Kew:
Arabic medicine
Along with his fellow physicians of Ancient Rome, Aulus Cornelius Celsus, Galen, Hippocrates and Soranus of Ephesus, Dioscorides had a major and long-lasting effect on Arabic medicine as well as medical practice across Europe. was one of the first scientific works to be translated from Greek into Arabic (Arabic:Hayūlā ʿilāj al-ṭibb). It was translated first into Syriac and then into Arabic in 9th century Baghdad. The translators were most often Syriac Christians, such as Hunayn ibn Ishaq, and their work is known to have been sponsored by local rulers, such as the Artuqids.
Manuscripts
Leiden Dioscurides (1083)
Manuscript (Or. 289), dated 1083, an illustrated Arabic translation of Dioscurides' . The work was originally translated from Greek into Arabic via Syriac by Hunayn ibn Ishaq (810–873) with the collaboration of Stephanus b. Bāsīl between 847–861. This translation was slightly revised by Ḥusayn b. Ibrāhīm al-Nātilī in 990–991. The current copy is based on an exemplar in the hand of al-Nātilī. The work was offered to the amīr of Samarqand, Abū ʿAlī al-Simǧūrī. Acquired by Levinus Warner (1619–1665) and bequeathed to Leiden University Library on his death.
A digitized version is available via Leiden's Digital Collections.
1224 manuscript
One manuscript is dated to 1224, but its provenance is uncertain. It is generally cautiously attributed to "Iraq or Northern Jazira, possibly Baghdad". Its folios have been dispersed among multiple institutions and collectors.
Istanbul, Topkapı Palace, Ahmet II 2127 (1229)
This copy was created by Abd Al-Jabbar ibn Ali in 1229.
References
Cited sources
(subscription required for online access)
Further reading
Manuscripts and editions
Note: Editions may vary by both text and numbering of chapters
Arabic
Digitized version of Kitāb al-Ḥašāʾiš fī hāyūlā al-ʿilāg ̌al-ṭibbī Or. 289 Illustrated Arabic De Materia Medica of Dioscorides from Digital Collections at Leiden University Libraries
English
The Greek Herbal of Dioscorides ... Englished by John Goodyer A. D. 1655, edited by R.T. Gunter (1933).
De materia medica, translated by Lily Y. Beck (2005). Hildesheim: Olms-Weidman.
(from the Latin, after John Goodyer 1655])
French
Edition of Martin Mathee, Lyon (1559) in six books
German
Edition of J Berendes, Stuttgart 1902
Greek
Naples Dioscurides: Codex ex Vindobonensis Graecus 1 ca 500 AD, at Biblioteca Nazionale di Napoli site
English description, World Digital Library
Edition of Karl Gottlob Kühn, being Volume XXV of his Medicorum Graecorum Opera, Leipzig 1829, together with annotation and parallel text in Latin
Book I – Book II – Book III – Book IV – Book V – Indices
Edition of Max Wellman, Berlin
Books I, II – Books III, IV – Book V
Greek and Latin
(Index in frontispiece)
Latin
Edition of Jean Ruel 1552
Index – Preface – Book I – Book II – Book III – Book IV – Book V
De Medica Materia : libri sex, Ioanne Ruellio Suesseionensi interprete, translated by Jean Ruel (1546).
De Materia medica : libri V Eiusdem de Venenis Libri duo. Interprete Iano Antonio Saraceno Lugdunaeo, Medico, translated by Janus Antonius Saracenus (1598).
Spanish
Edition of Andres de Laguna 1570 site
Andres de Laguna, published at Antwerp 1555 , at Biblioteca Nacional de España site
Dioscórides Interactivo Ediciones Universidad Salamanca. Spanish and Greek.
External links
Ancient Roman medicine
Medical manuals
Herbals
History of pharmacy
Natural history books
Pharmacology literature
Pharmacopoeias
1st-century books in Latin | De materia medica | [
"Chemistry"
] | 3,747 | [
"Pharmacology",
"Pharmacology literature"
] |
42,842,335 | https://en.wikipedia.org/wiki/Norwegian%20Institute%20for%20Water%20Research | The Norwegian Institute for Water Research (NIVA) is an environmental research organisation which researches, monitors, assesses and studies freshwater, coastal and marine environments and environmental technology.
Services and research
NIVA's areas of work include environmental contaminants, biodiversity and climate related issues. NIVA's research reports can be accessed through BIBSYS, and all reports from 1956 until 2015 are available for download. Some of the more widely read articles are also made available by Sciencenordic.com and forskning.no (articles in Norwegian only). The institute has twelve sections, led by research managers: Aquaculture, Biodiversity, Innovation, International projects and cooperation, Chemicals, Effects of climate change, Laboratory services, Environmental contaminants,
Environmental monitoring, Environmental technology and Measures against pollution.
In 2012 NIVA was in the news after its scientists developed a method of studying drug use in cities though analysis of sewage.
Organisation
NIVA was founded in 1958 and in 2015 is a non-profit research foundation. Its board is appointed by the Norwegian Ministry of the Environment, the Research Council of Norway and its employees. NIVA's Head Office is at the Oslo Innovation Centre in Oslo, with regional offices in Bergen, Grimstad and Hamar, as well as a large scale research facility in the Oslo Fjord. The organization is certified with ISO9001, and laboratory activities are accredited in accordance with ISO17025.
NIVA has about 200 employees. Two-thirds of these have educational backgrounds in water sciences and more than half work in research.
Subsidiaries
NIVA has several wholly and partly owned subsidiaries:
Akvaplan-niva AS is a research and consultancy firm in the fields of aquaculture, marine biology and freshwater biology. The company offers services related to environmental contaminants, biology, oceanography, chemistry and geology. Akvaplan-niva was founded in 1984 and is located at the Fram Centre in Tromsø. The company is wholly owned by NIVA.
AquaBiota Water Research AB is NIVA's subsidiary in Sweden. The company uses geographical information systems (GIS) to analyse and model biological and oceanographic phenomena. Around half of AquaBiota's business involves basic research; the other half consists of projects for government agencies and industry in Sweden and internationally.
BallastTech-NIVA AS was one of the first companies in the world to establish a full-scale centre for land-based testing of equipment for the treatment of ballast water in accordance with the International Maritime Organization (IMO). The testing centre is located at NIVA's marine research station at Solbergstrand, from Oslo. BallastTech-NIVA AS is a wholly owned subsidiary of NIVA-tech AS.
NIVA Chile SA is owned 50% by NIVA and 50% by NIVA-tech AS. The organisation's primary focus is to provide advice about water-quality and -treatment to the Chilean aquaculture industry.
NIVA-tech AS works with commercial applications for NIVA's competence, services, products and technology.
NIVA China conducts research and development on environmental challenges in China.
References
External links
Official home page
NIVA at BIBSYS Open Access
Environmental research institutes
Research institutes in Norway
Water organizations
Water supply and sanitation in Norway
Research institutes established in 1958
Non-profit organisations based in Norway
Organisations based in Oslo
1958 establishments in Norway | Norwegian Institute for Water Research | [
"Environmental_science"
] | 689 | [
"Environmental research institutes",
"Environmental research"
] |
42,843,131 | https://en.wikipedia.org/wiki/Verbal%20autopsy | Verbal autopsy (VA) is a method of gathering information about symptoms and circumstances for a deceased individual to determine their cause of death. Health information and a description of events prior to death are acquired from conversations or interviews with a person or persons familiar with the deceased and analyzed by health professionals or computer algorithms to assign likely cause(s) of death.
Verbal autopsy is used in settings where most deaths are otherwise undocumented, which typically means in low- and middle-income countries. Estimates suggest a majority of the 60 million annual global deaths occur without medical attention or official medical certification of the cause of death. VA attempts to establish causes of death for otherwise undocumented subjects, allowing scientists to analyze disease patterns and direct public health policy decisions.
Noteworthy large-scale uses of the verbal autopsy method include the Million Death Study in India, China's national program to document causes of death in rural areas, the Global Burden of Disease Study 2010, and the INDEPTH Network multi-site study. VA is increasingly recognised as an important component of national CRVS (civil registration and vital statistics) systems.
Origins
The term verbal autopsy was first coined in a project of the Department of International Health of Johns Hopkins School of Hygiene and Public Health which ran from 1965 to 1973 in Punjab, India. Two research projects were located in villages near Ludhiana, with headquarters in Narangwal village. Objectives of the projects were
to assess the relationships between nutrition, infection and child development, and
the acceptance of family planning services by rural communities in response to maternal and early child care service packages. Main providers of health care were Lady Health Visitors (LHVs) and Auxiliary Nurse Midwives (ANMs) resident in each of the study villages in the nutrition- and population studies, respectively. All had received a six-week training prior to onset of the program, followed by monthly reviews, re-training and feed-back on service aspects specific to their group of villages. Input services in the Nutrition villages originally consisted of "feeding centres" and health care for under-5s, and on maternal and newborn health care services in the population cells. Early in 1971, results from the nutrition villages showed no significant decrease in child mortality, and causes and circumstances of child deaths had remained largely unknown. In response, an information system was established, wherein all child deaths in the villages had to be reported to the Narangwal Project Office by the resident health worker within five days. One of the project physicians then went to the concerned family and through intense questioning of close relatives as to the signs and symptoms of the process leading to death, review of the child's health records, supplemented by visits to the external health care provider if such was the case, established possible reasons for, and a most likely cause of death. Using this method and following an analysis of the initial 45 deaths, diarrheal disease, lower respiratory tract infections and malnutrition were identified as the three principal causes among the 8 days to 3-year-old children. Among the 45, one had died from neonatal tetanus. Shortly thereafter, the same process was extended to all villages of the two projects featuring childcare as one of the service inputs. In response to the results, intervention methodologies specific to identified health care priorities were elaborated and introduced in both projects. In 1972, results from the investigation were presented for 124 child deaths during the first seven days of life, and 117 deaths from 8 days to 5 years of age at a conference in Srinagar, Kashmir. The term Verbal Autopsy was used 'in irony' by a visiting medical dignitary who not only questioned the results but also the method, labelling it "unscientific". The term was retained by the then director of the two projects, Carl E. Taylor, chairman of the Department of International Health who also chaired the conference. Through introduction of specific service packages specifically for the control of DD, ARI, and Neonatal Tetanus, child mortality dropped significantly in the study villages of both the Nutrition and Population projects.
Seven years later (1980), the Ministry of Health of Egypt conducted an investigation for prevention of child mortality from DD using a variety of intervention methods for a total population of 200,000, including 29000 children below the age of 5 in three different districts. The VA method as originally developed in Narangwal was slightly modified to the Egyptian setting and again used to identify prevailing mortality patterns among preschoolers. Following implementation of different treatment schedules, child mortality rates dropped significantly in specific input villages over the period of study. The project site was re-visited six years following completion of the investigation confirming utility and effectiveness of the VA method, and applied intervention modalities respectively.
Development
Many iterations and variations of the questionnaires used in VA have been developed by health professionals and researchers. The World Health Organization (WHO), exercising its global mandate to set norms and standards for health, published a book outlining VA standards in 2007. At that time, the emphasis was primarily on standard paper questionnaires that could subsequently be evaluated by physicians to assign causes of death.
However, work was already underway in parallel to develop methods for automatically processing VA interview material, because the time, cost and consistency with which physicians were able to assign causes of death to VA interview material were major constraints on the overall process, particularly for large-scale approaches. Additionally, the reason that many deaths were not certified routinely in resource-challenged settings was often associated with a lack of available physicians. Tentative versions of automatic methods were tested in Vietnam in 2003 and in Ethiopia in 2006. Methodological development was led by Prof. Peter Byass at the Umeå Centre for Global Health Research in Sweden, and the name InterVA (for Interpreting Verbal Autopsy) was coined.
As it became increasingly clear that automated interpretation of VA was a promising approach, WHO gave further attention to the structure of the VA interview from the perspective that the interview material might be automatically processed. In 2012 WHO published the first VA standard that was specifically designed for automated processing, defining both interview questions and cause of death categories linked to ICD-10. This was followed by the release of the InterVA-4 model which directly corresponded to the 2012 WHO standard. The open-access InterVA-4 knowledge base was also incorporated into the related InsilicoVA model, which set out to analyse standard VA data using a more complex statistical method.
Around the same time, the Population Health Metrics Research Consortium (PHMRC) were undertaking an empirical study based at several tertiary hospitals to collect a reference database linking clinically investigated final illnesses to subsequent VA interviews. This was envisaged as a knowledge base for building automated VA models, and several possible strategies were proposed at a conference in Indonesia in 2011. The reference database was subsequently made publicly available. However, it was not fully compliant with the 2012 WHO VA standard for VA interviews or cause of death categories. An automated model called SmartVA-Analyze, based on the content of the PHMRC reference database and using the Tariff model, was subsequently released.
On October 1, 2019, Bloomberg Philanthropies announced it would spend $120 million over the next four years to develop verbal autopsies in 25 countries.
Current status
In order to harmonize the various VA standards and approaches in use, WHO undertook further revisions and generated a 2016 WHO VA standard. This 2016 WHO standard included all the items from the 2012 WHO version plus all the items from the SmartVA tool as an important strategy for the revision. On the same principle that the 2016 WHO standard was intended to harmonise and unify available VA resources, InterVA-5 was released during 2018 as an integrating model which has the capacity to process input data in the 2012 WHO, SmartVA or 2016 WHO formats and generate causes of death according to the 2016 WHO standard.
References
Forensic techniques
Interviews
Causes of death
Epidemiology
Public health | Verbal autopsy | [
"Environmental_science"
] | 1,599 | [
"Epidemiology",
"Environmental social science"
] |
42,843,259 | https://en.wikipedia.org/wiki/China%20Energy%20Label | The China Energy Label (CEL; ) is an energy consumption label for products in China, similar to the European Union energy label. Manufacturers of specified electronic devices are obligated to attach a CEL label to their goods to inform China-based consumers of the product's energy efficiency. The label includes the product's energy efficiency class (1–5) as well as information regarding its energy consumption.
Targets
The CEL shows the level of energy consumption and, thus, the energy efficiency of a product. The CEL aims to encourage customers to buy energy efficient products. The target to increase energy efficiency and the acceptance of Chinese consumers towards energy efficient products is highly important, since China is the world's largest energy consumer.
Responsible authority
Applications are to be filed at the China Energy Label Center (CELC), which is the main authority for CEL-classification.
Products requiring CEL
Since the introduction of China Energy Label in 2005, more than 25 product groups have become CEL-mandatory, while additional classes continually being added to the product catalogue. For every product that requires CEL, a GB-Standard has been implemented. Among the CEL mandatory products are:
Motors
Gas kettles
Photocopiers
Water kettles
Refrigerators
Air compressors
Air conditioners
Washing machines
Flat-screen televisions
Fluorescent tube
See also
EnergyGuide, the energy rating label in the United States
Energy rating label, the energy rating label in the Australia and New Zealand
European Union energy label, the energy rating label in the European Economic Area
References
External links
China Energy Label
China Compatible Labels
Government agencies of China
Energy conservation
Energy policy
Energy in China
Rating systems
Energy consumption
Labels | China Energy Label | [
"Environmental_science"
] | 334 | [
"Environmental social science",
"Energy policy"
] |
42,844,729 | https://en.wikipedia.org/wiki/Smart%20Cell | Smart Cells are radio access nodes that provide wireless connectivity across multiple spectrum ranges and technologies. As of January 2014, Macrocells, Small Cells, and Wi-Fi connections were the primary means of data connectivity. For these types of cells, the spectrum utilized is static and is based on the antenna installed. A Smart Cell may transmit multiple frequencies and technologies which are controlled by the software and not the hardware (antenna).
Smart Cells are currently in the research and development stage, but support software-defined networks, which are proliferating the current mobile network structure, are being supported.
It's possible that Smart Cells will lower capital and operational costs due to reduced equipment and manual manipulations needed to modify cell site coverage. The term Smart Cell is also used to identify other technologies that enhance cell sites where it has reduced the need to manually manipulate radio access equipment or add additional carriers at a radio access node.
References
Smart devices
Mobile telecommunications
Radio communications | Smart Cell | [
"Technology",
"Engineering"
] | 191 | [
"Home automation",
"Telecommunications engineering",
"Radio communications",
"Mobile telecommunications",
"Smart devices"
] |
42,844,812 | https://en.wikipedia.org/wiki/The%20Foundation%20Review | The Foundation Review is a peer-reviewed academic journal that publishes articles for foundation staff. It covers evaluation results, tools, issues confronting the philanthropic sector, and reflective practice. The journal's editor in chief is Teresa (Teri) Behrens of Grand Valley State University. The journal was established in 2009 and is published quarterly by the Dorothy A. Johnson Center for Philanthropy.
The Foundation Review is a hybrid journal, with a mix of subscriber-only and open-access content. Sponsored issues are open access. For non-sponsored issues, individual authors can pay an open-access fee. All content becomes open access after two years.
Abstracting and indexing
The Foundation Review is abstracted and indexed in Scopus and the Emerging Sources Citation Index and in the databases EBSCO, Gale, and ProQuest.
References
External links
Johnson Center for Philanthropy
Philanthropy
English-language journals
Quarterly journals
Academic journals established in 2009 | The Foundation Review | [
"Biology"
] | 187 | [
"Philanthropy",
"Behavior",
"Altruism"
] |
42,844,989 | https://en.wikipedia.org/wiki/Harmful%20Algal%20Bloom%20and%20Hypoxia%20Research%20and%20Control%20Amendments%20Act%20of%202014 | The Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2014 (; ) is a U.S. public law that reauthorizes and modifies the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 and would authorize the appropriation of $20.5 million annually through 2018 for the National Oceanic and Atmospheric Administration (NOAA) to mitigate the harmful effects of algal blooms and hypoxia.
The bill was introduced into the United States Senate during the 113th United States Congress.
Background
An algal bloom is a rapid increase or accumulation in the population of algae (typically microscopic) in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Freshwater algal blooms are the result of an excess of nutrients, particularly some phosphates. Harmful algal blooms are algal bloom events involving toxic or otherwise harmful phytoplankton such as dinoflagellates of the genus Alexandrium and Karenia or diatoms of the genus Pseudo-nitzschia. is an algal bloom that causes negative impacts to other organisms via production of natural toxins, mechanical damage to other organisms, or by other means. HABs are often associated with large-scale marine mortality events and have been associated with various types of shellfish poisonings. Such blooms often take on a red or brown hue and are known colloquially as red tides. It is unclear what causes HABs; their occurrence in some locations appears to be entirely natural, while in others they appear to be a result of human activities.
The program created by the Harmful Algal Bloom and Hypoxia Research and Control Act "has served as the federal government's research and response framework for harmful algal blooms." A report by the NOAA indicated that "U.S. seafood and tourism industries suffer annual losses of $82 million due to economic impacts of HABs."
Provisions of the bill
This summary is based largely on the summary provided by the Congressional Research Service, a public domain source.
The Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2014 would, in section 3, amend the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 to revise the membership requirements for the Inter-Agency Task Force on Harmful Algal Blooms and Hypoxia to require the Task Force to have a representative from the Centers for Disease Control and Prevention (CDC).
Section 4 would require the Under Secretary of Commerce for Oceans and Atmosphere, acting through the Task Force, to: (1) establish maintain, and periodically review a national harmful algal bloom and hypoxia program, and (2) develop and submit to Congress a comprehensive research plan and action strategy to address marine and freshwater harmful algal blooms and hypoxia.
The bill would establish additional Task Force functions, including: (1) expediting the interagency review process; and (2) promoting the development of new technologies for predicting, monitoring, and mitigating harmful algal bloom and hypoxia conditions.
The bill would require the National Oceanic and Atmospheric Administration (NOAA) to have primary responsibility in administering the Program.
The bill would establish the Under Secretary's duties, including administering merit-based, competitive grant funding to: (1) maintain and enhance baseline monitoring programs established by the Program, (2) support the Program's projects, and (3) address the research and management needs and the Action Strategy's priorities.
The bill would require the Administrator of the Environmental Protection Agency (EPA) to: (1) research the ecology and impacts of freshwater harmful algal blooms; (2) forecast and monitor event response to freshwater harmful algal blooms in lakes, rivers, estuaries, and reservoirs; and (3) ensure that activities carried under this Act focus on new approaches to addressing freshwater harmful algal blooms and are not duplicative of existing research and development programs authorized by this Act or any other law.
The bill would require the collection of monitoring and observation data under this Act to comply with all data standards and protocols developed pursuant to the Integrated Coastal and Ocean Observation System Act of 2009.
Section 7 would require the Administrator, through the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force, to report to appropriate congressional committees and the President on the progress made by activities directed by the Task Force and carried out or funded by EPA and other state and federal partners toward attainment of the goals of the Gulf Hypoxia Action Plan 2008 within 12 months after this Act's enactment and biennially thereafter.
Section 8 would require the Task Force to: (1) submit within 18 months to Congress and the President an integrated assessment that examines the causes, consequences, and approaches to reduce hypoxia and harmful algal blooms in the Great Lakes; and (2) develop and submit to Congress a plan, based on such assessment, for reducing, mitigating, and controlling such hypoxia and blooms.
Section 11 would authorize the departments and agencies represented on the Task Force to participate in interagency financing and share, transfer, receive, obligate, and expend funds appropriated to any member of the Task Force for the purposes of carrying out the Act.
Congressional Budget Office report
This summary is based largely on the summary provided by the Congressional Budget Office, as ordered reported by the House Committee on Science, Space, and Technology on May 21, 2014. This is a public domain source.
S. 1254 would reauthorize and modify the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998. The act would authorize the appropriation of $20.5 million annually through 2018 period for the National Oceanic and Atmospheric Administration (NOAA) to mitigate the harmful effects of algal blooms and hypoxia (reduced oxygen level) in certain bodies of water.
Assuming appropriation of the authorized amounts, the Congressional Budget Office (CBO) estimates that implementing the legislation would cost $78 million over the 2015-2019 period and $4 million after 2019. Enacting S. 1254 would not affect direct spending or revenues; therefore, pay-as-you-go procedures do not apply.
S. 1254 contains no intergovernmental or private-sector mandates as defined in the Unfunded Mandates Reform Act.
Procedural history
The Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2014 was introduced into the United States Senate on June 27, 2013 by Sen. Bill Nelson (D, FL). It was referred to the United States Senate Committee on Commerce, Science and Transportation. The Senate passed the bill on February 12, 2014 by unanimous consent. It was received in the United States House of Representatives on February 18, 2014 and referred to the United States House Committee on Science, Space and Technology, the United States House Committee on Natural Resources, the United States House Science Subcommittee on Environment, and the United States House Natural Resources Subcommittee on Fisheries, Wildlife, Oceans and Insular Affairs. It was reported (amended) by the House Committee on Science, Space, and Technology on June 5, 2014 alongside Report 113-471 part 1. The House passed the bill on June 9, 2014 in a voice vote. The United States Senate voted with unanimous consent to agree to the House amendments to the bill on June 17, 2014. President Barack Obama signed the bill into law on June 30, 2014.
Debate and discussion
Senator Rob Portman (R-OH), who co-sponsored the bill, supported it by saying that "this legislation takes critical steps toward protecting Lake Erie and grand Lake St. Marys from harmful algae that has become a tremendous problem for our state... we cannot afford to let this threat to our tourism, fishing industries, and health go unchecked." Portman described the changes this legislation would make to the existing law, saying that "it's changed to provide more funding than has been provided in previous appropriations, but also to prioritize freshwater, and specifically talks about the Great Lakes, which it did not previously." Lake Erie, which Portman's state of Ohio borders, experienced a harmful algal bloom in 2011 and continues to have smaller ones.
The environmental organization Ocean Champions supported legislation that would address the problem of harmful algal blooms.
See also
List of bills in the 113th United States Congress
References
External links
Library of Congress - Thomas S. 1254
beta.congress.gov S. 1254
GovTrack.us S. 1254
OpenCongress.org S. 1254
WashingtonWatch.com S. 1254
Congressional Budget Office's report on S. 1254
Report 113-471 part 1 on S. 1254
United States federal environmental legislation
Acts of the 113th United States Congress
Algal blooms | Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2014 | [
"Chemistry",
"Biology",
"Environmental_science"
] | 1,800 | [
"Algae",
"Water treatment",
"Water pollution",
"Water quality indicators",
"Algal blooms"
] |
42,844,994 | https://en.wikipedia.org/wiki/Stela%20of%20Pasenhor | The Stela of Pasenhor, also known as Stela of Harpeson in older literature, is an ancient Egyptian limestone stela dating back to the Year 37 of pharaoh Shoshenq V of the 22nd Dynasty (c.730 BCE). It was found in the Serapeum of Saqqara by Auguste Mariette and later moved to The Louvre, where it is still.
The stela was intended to commemorate the death of an Apis bull occurred in this year and its author, the Priest of Ptah and Prophet of Neith, Pasenhor (B), was the performer of the funerary rites. Despite the commemorative nature of the stela, Pasenhor took the opportunity to inscribe his own genealogy on it.
The first part of the stela reflects its original purpose:
This god (i.e. the Apis) was introduced to his father Ptah (i.e. was "enthroned"), in the Year 12, fourth month of the second season, fourth day, of King Aakheperre Shoshenq (V), given life. He was born in the year 11 of his majesty; he rested in his place in Tazoser (i.e. was buried in the cemetery) in the year 37, third month of the first season, day 27, of his majesty. May he grant life, prosperity, health, and joy of heart to his beloved son, the prophet of Neith, Pasenhor.
After that, Pasenhor begins to trace back along his genealogy for sixteen generations, until about the end of the 20th Dynasty:
Pasenhor's genealogy is quite important since he was a member of the royal family and could claim common ancestors with many pharaohs of the 22nd Dynasty. Thanks to the stela, we know more about the dynasty's origin and chronology, as well as the name of some otherwise unattested royal wives such as Karomama A, Tashedkhonsu and Kapes.
See also
Genealogy of Ankhefensekhmet
References
Bibliography
James Henry Breasted, Ancient Records of Egypt, volume IV: the Twentieh to the Twenty-sixth Dynasties, Chicago, The University of Chicago Press, 1906, § 785-792.
Kenneth Kitchen, The Third Intermediate Period in Egypt (1100–650 BC), 1996, Aris & Phillips Limited, Warminster, , § 85ff.
Pasenhor
Pasenhor
Pasenhor
Egyptian antiquities in the Louvre
Ancient Egyptian King lists
Pasenhor
Genealogy
Ptah
Ancient Egyptian family trees | Stela of Pasenhor | [
"Biology"
] | 531 | [
"Phylogenetics",
"Genealogy"
] |
42,845,378 | https://en.wikipedia.org/wiki/German%20Aeronautical%20Research%20Institute | The Deutsche Luftfahrtforschungsanstalt (LFA/German Aeronautical Research Institute, also known as the Hermann Göring Research Institute) was a secret German facility for airframe, aeroengine, and aircraft weapons testing during the Second World War. It was located near Völkenrode, on the western outskirts of Braunschweig (Brunswick), near what became the Inner German Border. The site was Germany's "most advanced and extensive [aviation] research establishment, outside of the existing Erprobungsstelle network of military aviation evaluation facilities, themselves headquartered at Rechlin.
History and activities
Site layout
It was a site begun in October 1935. The first wind tunnel was begun in November 1936. Most of the sixty buildings, scattered around the site, did not exceed treetop height, and all were well-camouflaged, to reduce the chance of them being detected by aerial reconnaissance and to avoid making them targets, as the wind tunnels of the Deutsche Versuchsanstalt für Luftfahrt (DVL) in Adlershof (near Berlin) or the Aerodynamische Versuchsanstalt (AVA, part of today's DLR agency) at the University of Göttingen were.
The buildings were in five groups. The Institute of Aerodynamics had five wind tunnels, while the Institute of Gas Dynamics had its own high-speed tunnel; both were at the southern end of the campus. The static testing station of the Institute of Strength Properties was to the west; the Institute of Engine Research, the east. Weapons research was done by the Institute of Kinematics in a -long tunnel in the northwest corner. These were accompanied by administration buildings, a canteen, a telephone exchange, guard houses, generators, and other facilities.
To help reduce the risk of detection, there were no railway lines in, nor overhead power lines, nor any chimneys; and uniquely for an aviation research facility of its time in Germany, no runways, taxiways or hardstands for active aviation operations; just about all of the facility's infrastructure needs were supplied underground from Braunschweig, including steam heat.
In addition, there were four hundred houses in Völkenrode for the 1,500 or so workers and scientists.
Work and research
Wind tunnels
Each of the wind tunnels at LFA was given an "A" number. A1 had a circular nozzle in diameter, producing a maximum speed of ; it entered service in 1937, the year after construction began on facilities. A2 measured long and had a test section in diameter (coated with Keratylene to keep the flow smooth), capable of generating test speeds (depending on the model's scale) of between Mach 1 and 1.2. It was driven by a pair of DC electric motors, and fitted with interferometer and striation gear for study of flow patterns. Begun in 1937, it first ran in 1939. It did, however, suffer with problems of vibration, leading the research teams to rely on a Rheinmetall-Börsig F25 free-flight research rocket with models mounted in the nose. The A3 tunnel, largest at the LFA site, had an test section with a maximum speed of and a working length of , enough to accommodate a Messerschmitt Bf 109's fuselage. It was powered by a pair of . The A9 building housed a pair of supersonic wind tunnels, each driven by a motor, with a maximum speed of Mach 1.5, but a test section diameter of only .
Materials testing
Along with direct aerodynamic research, LFA did testing on materials (though not, apparently, of parts) and on aircraft engines. The engine work included testing of turbine and turbine blade shapes, ceramic turbine blades, cooling of turbine blades (including liquid cooling), bearings, detonation, and several types of heat exchangers, among other things.
Engineering
The test centre assisted the BMW firm in developing the factory-produced forward cowling — which had the engine's oil cooler integrated into it from the beginning — for their BMW 801 fourteen-cylinder radial engine used in many German Luftwaffe military aircraft, most importantly the Focke-Wulf Fw 190A; trials indicated it was possible to reduce drag enough to save , as well as to maximize pressure build-up to assist cooling. It also helped in development of the pioneering Argus As 014 pulsejet used in the V-1. In collaboration with Göttingen and DVL (Berlin-Adlershof), it also contributed to the development of the swept wing (what Germans called Pfeilflügel, or "arrow wing").
Among the engine projects worked on at LFA was a toroidal (swing-piston) design by Otto Lutz of Büssing, a concept akin to the Wankel; work was also done by Junkers and Bosch.
Significance and legacy
LFA remained so secret, the Allied air forces never bombed it.
Postwar, the Fedden Mission of a Ministry of Aircraft Production team led by Roy Fedden visited the site.
Notes
Sources
Christopher, John. The Race for Hitler's X-Planes. The Mill, Gloucestershire: History Press, 2013.
External links
German language page on the LFA facility's history and still-standing buildings
Google Translate's English language translation of the above link, dated June 14, 2015
Research institutes in Germany
Aviation in Germany
Aviation research institutes
Aeronautics organizations
German military aviation history
Organisations based in Braunschweig
1935 establishments in Germany
Organizations established in 1935
Research and development in Nazi Germany
Aerospace research institutes | German Aeronautical Research Institute | [
"Engineering"
] | 1,138 | [
"Aeronautics organizations"
] |
42,848,605 | https://en.wikipedia.org/wiki/Habitable%20Planets%20for%20Man | Habitable Planets For Man is a work by Stephen Dole, first edition published by Blaisdell Publishing Company, A division of Ginn and Company, copyright 1964 by The RAND Corporation. Originally 158 pages, it was republished in a posthumous second edition in 2007, as Planets for Man.
The revised edition, 174 pages, contains a detailed scientific study on the nature of worlds that may support life in the universe, the probability of their existence, and ways of finding them. It includes assessments of 14 stars within 22 light years with a relatively high probability of having habitable planets (a collective probability of 43%). Writing in a Scientific American blog in 2011, Caleb Scharf called it "extraordinarily detailed and prescient".
Publication data
External links
Official RAND Corporation Site
References
1964 non-fiction books
2007 non-fiction books
Astronomy books | Habitable Planets for Man | [
"Astronomy"
] | 174 | [
"Astronomy books",
"Works about astronomy"
] |
42,848,638 | https://en.wikipedia.org/wiki/Transcription-mediated%20amplification | Transcription-mediated amplification (TMA) is an isothermal (performed at constant temperature), single-tube nucleic acid amplification system utilizing two enzymes, RNA polymerase and reverse transcriptase.
"Amplification" means creating many more copies of a strand of nucleic acid than was present at first, in order to readily detect it or test it. Rapidly amplifying the target RNA/DNA allows a lab to simultaneously detect multiple pathogenic organisms in a single tube. TMA technology allows a clinical laboratory to perform nucleic acid test (NAT) assays for blood screening with fewer steps, less processing time, and faster results.
It is used in molecular biology, forensics, and medicine for the rapid identification and diagnosis of pathogenic organisms.
In contrast to similar techniques such as polymerase chain reaction and ligase chain reaction, this method involves RNA transcription (via RNA polymerase) and DNA synthesis (via reverse transcriptase) to produce an RNA amplicon (the source or product of amplification) from a target nucleic acid. This technique can be used to target both RNA and DNA.
Transcription-mediated amplification has several advantages compared to other amplification methods including:
TMA is isothermal, meaning it is performed at constant temperature. As such, a water bath or heat block can be used instead of a thermal cycler.
TMA produces RNA amplicon rather than DNA amplicon. Since RNA is more labile in a laboratory environment, this reduces the possibility of carry-over contamination.
TMA produces 100–1000 copies per cycle (PCR and LCR exponentially doubles each cycle). This results in a 10 billion fold increase of DNA (or RNA) copies within about 15–30 minutes.
References
Daniel L. Kacian, Timothy J. Fultz: Nucleic acid sequence amplification methods. In: Biotechnology Advances 1995, 13.3, S. 569–569
From: http://www.gen-probe.com
Molecular biology | Transcription-mediated amplification | [
"Chemistry",
"Biology"
] | 416 | [
"Biochemistry stubs",
"Biotechnology stubs",
"Biochemistry",
"Molecular biology"
] |
42,848,685 | https://en.wikipedia.org/wiki/S%20Pictoris | S Pictoris is a Mira variable-type star in the constellation Pictor. It ranges between apparent magnitude 6.5 and 14.0, and spectral types M6.5e to M8III-IIe, over a period of 422 days.
References
Durchmusterung objects
033894
024126
Pictoris, S
Pictor
M-type giants
Mira variables | S Pictoris | [
"Astronomy"
] | 82 | [
"Pictor",
"Constellations"
] |
42,848,711 | https://en.wikipedia.org/wiki/W.%20Clark%20Still | William Clark Still (born 1946) is an American organic chemist. As a distinguished professor at Columbia University, Clark Still made significant contributions to the field of organic chemistry, particularly in the areas of natural product synthesis, reaction development, conformational analysis, macrocyclic stereocontrol, and computational chemistry. Still and coworkers also developed the purification technique known as flash column chromatography which is widely used for the purification of organic compounds.
Major contributions
Total synthesis
Periplanone B
In 1979, Still reported the first total synthesis of periplanone B, the potent sex pheromone of the American cockroach. Although the structural connectivity of this compound had been established spectroscopically, Still's synthesis confirmed the relative stereochemical relationships present in this natural product. A key step in this synthesis makes use of an anionic oxy-Cope rearrangement to form the macrocyclic 10-membered ring found in periplanone B. In this transformation, the initial tertiary alcohol was treated with potassium hydride and 18-crown-6 at elevated temperature to induce the rearrangement, and the resulting enolate was trapped with chlorotrimethylsilane to form the macrocyclic silyl enol ether as a single diastereomer. This intermediate was then transformed into a key enone substrate over the course of five steps including Rubottom oxidation, TBS protection of the secondary alcohol, and formation of the exocyclic alkene via a selenoxide rearrangements.
These transformations set the stage for the introduction of both epoxide groups, which were formed with high levels of diastereoselectivity based on the principles of macrocyclic stereocontrol. The first epoxide was introduced via nucleophilic epoxidation of the enone using potassium hydride and tert-butylhydroperoxide; this led to the formation of a 4:1 mixture of diastereomeric epoxides, favoring the desired isomer in which attack had occurred from the peripheral face of the enone. At this stage, the ketone was transformed into the second epoxide group using the Johnson-Corey-Chaykovsky reaction; notably, the product was formed as a single diastereomer, again due to initial peripheral attack of the dimethylsulfonium methylide nucleophile on the ketone. Subsequent removal of the TBS protecting group and Sarett oxidation of the resulting secondary alcohol completed the total synthesis of racemic periplanone B.
Monensin
In 1980, Still and coworkers reported the total synthesis of monensin, a complex polyether natural product that acts as an ionophore. One of the key steps in this route is the late-stage union of two advanced fragments via an intermolecular aldol reaction. In this reaction, low-temperature deprotonation of the methyl ketone with lithium diisopropylamide formed the kinetic enolate which then underwent transmetalation upon the addition of magnesium bromide. Subsequent addition of the aldehyde component initiated a diastereoselective aldol reaction, forming the desired beta-hydroxyketone in 75% yield as a 3:1 mixture of diastereomers. Notably, this instance of acyclic stereocontrol is consistent with the Cram-Felkin-Anh model for the addition of nucleophiles to an aldehyde bearing an existing stereocenter in the alpha position.
Having united these two complex fragments, Still was able to complete the synthesis of monensin in three additional steps. First, hydrogenolysis of the benzyl group afforded the free primary alcohol under standard conditions. Next, cleavage of the triethylsilyl (TES) protecting groups was achieved in the presence of para-toluenesulfonic acid; the resulting free secondary alcohols then engaged the ketone in a spontaneous cyclization reaction to form the thermodynamic spiroketal linkage. Finally, hydrolysis of the methyl ester under basic conditions furnished the sodium salt of monensin, completing the synthesis of this challenging natural product.
Method development
Wittig-Still rearrangement
The 2,3-Wittig rearrangement is a useful carbon-carbon bond forming reaction that transforms an allyl ether into a homoallylic alcohol. However, a significant limitation of this reaction is the difficulty in forming the alkoxy-substituted carbanion which initiates the 2,3-sigmatropic rearrangement. Traditionally, this required the use of a strong base and the presence of a stabilizing group to enable deprotonation of the ether substrate. In 1978, Still dramatically increased the scope of the 2,3-Wittig rearrangement by introducing an organotin-substituted ether as a precursor to the alkoxy-substituted carbanion. In this procedure, transmetalation of the organotin group can be achieved chemoselectively at low temperature using n-butyllithium to form an alpha-lithiated ether that undergoes the desired 2,3-sigmatropic rearrangement. This variation of the traditional 2,3-Wittig reaction is known as the Wittig-Still rearrangement.
An application of the Wittig-Still rearrangement in the context of natural product synthesis can be seen in Still's 1979 formal synthesis of the Cecropia juvenile hormone. The organotin-substituted ether that serves as the substrate for the rearrangement was readily prepared by bis-alkylation of the corresponding diol with iodomethyltributyltin. Treatment of this compound with two equivalents of n-butyllithium at low temperature resulted in transmetalation, initiating a double 2,3-sigmatropic rearrangement to give the bis-homoallylic alcohol product in 79% yield. Notably, this rearrangement is highly stereoselective with regard to the geometry of the trisubstituted olefins, giving exclusively the (Z,Z)-isomer shown.
Still-Gennari alkenation
The Horner-Wadsworth-Emmons reaction is a widely used olefination reaction in which a phosphonate-stabilized carbanion reacts with an aldehyde or ketone to form an alkene. In the standard HWE reaction, the phosphonate ester contains alkoxy substituents (typically methoxy or ethoxy), producing an E-alkene as the major product. In 1983, Still and Gennari reported that simply substituting the more electron-withdrawing 2,2,2-trifluoroethoxy groups on the phosphonate component reversed the stereoselectivity to produce predominantly Z-alkenes. The use of a non-coordinating counterion was also found to be critical for high levels of Z-selectivity; this is typically accomplished by using a base with a potassium counterion in the presence of 18-crown-6. Taken together, this protocol is known as the Still-Gennari modification of the Horner-Wadsworth-Emmons reaction or, alternatively, as the Still-Gennari olefination.
Although the mechanism of this reaction has not been fully elucidated, it is speculated that the use of an electron-deficient phosphonate accelerates elimination of the oxaphosphatane intermediate. This renders the initial addition of the phosphonate-stabilized carbanion to the aldehyde effectively irreversible, leading to Z-selectivity in analogy to the standard Wittig reaction.
Flash column chromatography
In 1978, Still and coworkers published a highly influential paper reporting a purification technique known as flash column chromatography. Prior to this report, column chromatography using silica gel as a stationary phase had already been established as a valuable method for the separation and purification of organic compounds. However, elution of the solvent by gravity alone was often a tedious process, requiring several hours and leading to poor separations due to band broadening via diffusion. Still's innovation was to apply pressure to the top of the column to increase the speed of solvent elution. Not only did this drastically reduce the time required to run the column, but it also allowed for the routine separation of compounds having an Rf difference of 0.10 or greater. After optimizing this procedure, Still compiled a table correlating column diameter, volume of eluant, amount of sample, and typical fraction size, providing a useful guide for application of this technique in the laboratory. Today, flash column chromatography is one of the most important methods for the purification of organic compounds, especially when working on a small scale (< 50 mg) where the techniques of recrystallization and distillation are impractical. Still's paper describing flash column chromatography remains his most highly cited publication and holds the distinction of being one of the most frequently downloaded papers from the Journal of Organic Chemistry, despite being published over 35 years ago.
Computational chemistry and MacroModel
In addition to his contributions to synthetic organic chemistry, Clark Still was an early pioneer in applying computational methods to the study of organic compounds. Conformational analysis was integral to Still's study of macrocyclic stereocontrol, and there was a general need for a fast and reliable computational method for predicting an organic molecule's lowest energy conformation. In order to address the problem, Still and coworkers reported a simple Monte Carlo method for searching conformational space in 1989. In this procedure, the internal coordinates for an organic molecule were varied at random, and the energy of the lowest energy conformation was determined after structure minimization. After each iteration, the minimum energy was compared to the values obtained previously in order to locate the global minimum; Still referred to this overall process as a Monte Carlo multiple-minimum search.
In an effort to make molecular modeling more accessible to practicing organic chemists, Still developed the integrated software program MacroModel in 1986 in association with Columbia University. Dr. Wayne Guida, a senior postdoctoral researcher in Still's group at the time, described the development of this software package in the following way:
One particularly notable feature of MacroModel was the inclusion of an implicit solvation model known as GB/SA (generalized Born model augmented with the hydrophobic solvent accessible surface area term). The GB/SA model simulated solvent interactions with organic molecules by incorporating a continuous solvent field instead of including explicit individual solvent molecules in the computation. Still disclosed a full description of MacroModel in the Journal of Computation Chemistry in 1990, and the rights to this software were later acquired by Schrodinger, Inc. in 1998.
References
1946 births
Living people
American organic chemists
Computational chemists | W. Clark Still | [
"Chemistry"
] | 2,272 | [
"Organic chemists",
"American organic chemists"
] |
42,848,720 | https://en.wikipedia.org/wiki/HD%2042540 | HD 42540, also known as HR 2196, is a giant star in the constellation Pictor. A class K2-3III orange giant, its apparent magnitude is 5.04 and it is approximately 389 light years away based on parallax.
This star was mistakenly catalogued as Mu Doradus (Mu Dor/μ Doradus/μ Dor) at incorrect coordinates, then assumed to be variable as no 5th-magnitude star was seen at that position. It also has the Gould designation 47 G. Pictoris.
References
Pictor
K-type giants
CD-62 235
028991
2196
042540
Suspected variables | HD 42540 | [
"Astronomy"
] | 135 | [
"Pictor",
"Constellations"
] |
42,850,491 | https://en.wikipedia.org/wiki/Dictionary%20of%20Scottish%20Architects | The Dictionary of Scottish Architects is a publicly available online database that provides biographical information about all architects known to have worked in Scotland between 1660 and 1980, and lists their works. Launched in 2006, it was compiled by a team led by Professor David Walker, now Emeritus Professor in the School of Art History at the University of St Andrews.
The database includes all the known works of architects based in Scotland, but only the Scottish works of English and Irish architects are included.
The database, which is available free of charge, is now managed and fully funded by Historic Environment Scotland.
References
External links
Official website
2006 establishments in Scotland
Architecture databases
Databases in Scotland
Historic Environment Scotland
Online person databases
Scottish websites
University of St Andrews | Dictionary of Scottish Architects | [
"Technology",
"Engineering"
] | 141 | [
"Architecture stubs",
"Computing stubs",
"Architecture",
"Computer network stubs"
] |
71,504,079 | https://en.wikipedia.org/wiki/Ibrokhim%20Abdurakhmonov | Ibrokhim Yulchiyevich Abdurakhmonov (; born 19 February 1975, Namangan Region, Uzbek SSR, USSR) is an Uzbek statesman and scientist. In 2012, he founded the Center for Genomics and Bioinformatics of Uzbekistan. He was the winner of the 2010 TWAS and ICAC awards for outstanding contributions to cotton genomics and biotechnology. In 2017–2022, he served as Minister of Innovative Development of the Republic of Uzbekistan.
In 2022, he was awarded the title of Silk Road Friendship Ambassador of the China International Culture Exchange Center (CICEC) and Global People magazine. In 2023, he was appointed as the Minister of Higher Education, Science and Innovation of the Republic of Uzbekistan. Member of the Academy of Sciences of Uzbekistan and the World Academy of Sciences. He is the Minister of Agriculture of the Republic of Uzbekistan from October 2023.
Biography
Abdurakhmonov was born on 19 February 1975 in the village of Govasoy, Chust district, Namangan Region. In 1997 he graduated from Tashkent State University (now the National University of Uzbekistan), receiving a bachelor's degree in biotechnology. Scholarship holder of the "Umid" Foundation. In 2001, he graduated from the Texas A&M University (US) with a Master of Science degree in plant breeding, after which he returned to Uzbekistan to continue his scientific activities.
In 2002, Abdurakhmonov defended his PhD thesis in the field of molecular genetics and took the position of senior researcher at the Institute of Genetics and Experimental Plant Biology of the Academy of Sciences of the Republic of Uzbekistan.
From 2002 to 2008, in collaboration with American scientists, he was engaged in research on cotton genomics. The result of these studies was the development of gene-knockout technology for obtaining high-quality, long-staple, high-yielding and early-ripening cotton varieties with a developed root system.
In 2008 he defended his doctoral thesis in the field of molecular genetics and received the degree of Doctor of Biological Sciences. In 2011 he was awarded the title of professor of molecular genetics and molecular biotechnology of the Academy of Sciences of Uzbekistan.
In 2012, Abdurakhmonov led the process of creating a new independent research center – the Center for Genomics and Bioinformatics at the Academy of Sciences of the Republic of Uzbekistan, the Ministry of Agriculture and Water Resources, the ″Uzpakhtasanoat″ Association, and was appointed its head. In 2016, this center was considered the largest scientific institution of the Academy of Sciences of Uzbekistan.
26 October 2014 in Muscat (Oman) became a member of the World Academy of Sciences. In 2017 he was appointed Acting Vice President of the Academy of Sciences of the Republic of Uzbekistan.
On 29 November 2017, President of Uzbekistan Shavkat Mirziyoyev appointed Abdurakhmonov to the post of Minister of Innovative Development of the Republic of Uzbekistan.
Under the leadership of Abdurakhmonov, the "Strategy for Innovative Development of the Republic of Uzbekistan for 2019 – 2021" and "Strategy for Innovative Development of the Republic of Uzbekistan for 2022–2026" were developed and subsequently approved by the Decree of the President of the Republic of Uzbekistan. By the Decree of the President of 7 July 2022, Abdurakhmonov was appointed Chairman of the Cotton Council.
At the end of 2022, the structure of the government was reorganized in Uzbekistan. By presidential decree, Abdurakhmonov was appointed to the position of Minister of Higher Education, Science and Innovation of the Republic of Uzbekistan. He has been working as the Minister of Agriculture of the Republic of Uzbekistan since October 24, 2023.
Scientific activity
In collaboration with colleagues from the University of Texas and the US Department of Agriculture, Abdurakhmonov developed technologies for "turning off" cotton genes (RNA interference), as well as the practical application of this technology. With the help of this gene-knockout technology, high-quality, long-staple, high-yielding and early-ripening cotton varieties with a developed root system were obtained.
Managed such projects as: "Molecular mapping of fiber yield and quality genes by using the germplasm resources of the cotton plant of Uzbekistan", "Characterization and molecular mapping of phytochromes and flowering genes in cotton", "Molecular characterization and association of quantitative trait genes/loci for Fusarium wilt disease" and"Evaluation of potential resistance of cotton germplasm against gall nematode, Fusarium wilt disease and development of candidate gene markers".
Awards
1998 – "Umid" Foundation Scholarship to study at Texas A&M University.
2004 and 2006 – first-degree diploma of the ″ISTEDOD″ Foundation for active participation in conferences held for specialists studying abroad.
2010 – TWAS Prize 2010 for fundamental research in the field of agriculture and contribution to the genetic diversity of the cotton genome.
2010 – State award "Kukrak Nishoni".
2013 – "2013 ICAC Cotton Researcher of the Year" by the International Cotton Advisory Committee (ICAC) for contributions to cotton genomics and biotechnology.
2016 – Breastplate "25 years of independence of Uzbekistan" for contribution to the development of science and technology in the country.
2018 – Scopus Award "The Best Scientist in Agriculture", jointly awarded by the scientific publishing house Elsevier and the Ministry of Higher Education of the Republic of Uzbekistan.
2021 – Breastplate "30 years of Independence of Uzbekistan" for contribution to the development of science and technology in the country.
2021 – State award of an “Honoured Innovator and Rationalizer” of the Republic of Uzbekistan, awarded by the President of the Republic of Uzbekistan;
2022 – "Silk Road Friendship Ambassador Award" from the Alliance of International Science Organizations, the China International Culture Exchange Center (CICEC) and the International People's Magazine (GPM) for contribution to the development of bilateral cooperation between foreign countries.
2023 – Winner of the UNESCO International Prize for Research in the Life Sciences.
2023 – He received the 8th VCANBIO International Cooperation Award in Biosciences and Medicine for his innovative achievements on joint COVID-19 vaccine development.
References
1975 births
Living people
People from Namangan Region
Members of the Academy of Sciences of Uzbekistan
National University of Uzbekistan alumni
Texas A&M University alumni
Molecular geneticists
Uzbekistani scientists | Ibrokhim Abdurakhmonov | [
"Biology"
] | 1,304 | [
"Molecular geneticists",
"Molecular genetics"
] |
71,504,422 | https://en.wikipedia.org/wiki/Time%20in%20Mali | Time in Mali is given by a single time zone, denoted as Greenwich Mean Time (GMT; UTC+00:00). Mali shares this time zone with several other countries, including fourteen in western Africa. Mali does not observe daylight saving time (DST).
IANA time zone database
In the IANA time zone database, Mali is given one zone in the file zone.tab – Africa/Bamako, which is an alias to Africa/Abidjan. "ML" refers to the country's ISO 3166-1 alpha-2 country code. Data for Mali directly from zone.tab of the IANA time zone database; columns marked with * are the columns from zone.tab itself:
See also
Time in Africa
List of time zones by country
References
External links
Current time in Mali at Time.is
Time in Mali at TimeAndDate.com
Time by country
Geography of Mali
Time in Africa | Time in Mali | [
"Physics"
] | 187 | [
"Spacetime",
"Physical quantities",
"Time",
"Time by country"
] |
71,504,681 | https://en.wikipedia.org/wiki/Sociology%20of%20absences | The sociology of absences is a sociological theory developed by Boaventura De Sousa Santos which, he says, "aims to show that what does not exist is in fact actively produced as non-existent, that is to say as an unbelievable alternative to what is supposed to exist”.
Southern epistemologies. Citizen movements and controversy over science is the title of the work in which Boaventura proposes this notion, which is articulated around the following thesis: “global justice is not possible without global cognitive justice".
For a decolonial sociology
The sociology of absences seeks to produce an epistemology of the south and aspires to be a critical, decolonial sociology that rejects eurocentric universalism. It is therefore a critique of the perceived hegemony of Eurocentric epistemology; an alternative to single thought and the standardization of the world.
Critique of Western Modernity
In Boaventura's thought, there exists in modernity an abyssal line between two kinds of beings on the planet: those who live above this line and those who live below. The first are in what Frantz Fanon calls the zone of being. The second are in the zone of non-being and undergo a racial inferiority which manifests itself both at the level of the processes of economic and political domination and exploitation, and at the level of epistemological processes. Hence, the notion of epistemic racism which results in “a hierarchy of colonial domination where the knowledge produced by Western subjects in the zone of being are considered a priori superior to the knowledge produced by non-Western subjects. The knowledge produced by subjects belonging to the zone of being is assumed to be automatically and universally valid for all contexts and all situations in the world. This situation constitutes a Eurocentric bias that Boaventura calls: indolent reason. It is, he says, a rationality that considers itself unique and exclusive, which does not make sufficient efforts to look at the inexhaustible wealth of the world. It manifests itself in two forms: metonymic reason and proleptic reason. “As a metonymical reason, it diminishes the present; as a proleptic reason, it expands the future to infinity. Boaventura proposes a different model in place of these: cosmopolitan rationality, one of the major processes of which is the sociology of absences.
In this regard, Edgar Morin writes: “Rationality is not a quality that Western civilization would have as a monopoly. The European West has long believed itself to be the owner of rationality, seeing only errors, illusions and backwardness in other cultures [...]”.
Aim of the sociology of absences
The goal of this sociology is to make impossible objects possible, to make absent objects present. To put it another way, it makes it possible to map the abyss mentioned above and it describes the mechanisms of rejection of certain forms of sociability into non-existence, into radical invisibility, into the negligible and the insignificant. It analyzes the processes by which colonialism, capitalism and patriarchy continue to produce abysmal exclusions. It highlights the way in which positivist scientific hegemony rejects a category of knowledge. This discarded or rejected knowledge constitutes a form of cognitive injustice that has been referred to as epistemicides.
Production logics of absences
Boaventura presents five logical formulations which constitute modes of production of absences, of non-existences.
The first is to ignore. It stems from the “monoculture of knowledge and rigour”. It reflects the idea that the only rigorous knowledge is scientific knowledge and considers the subject who does not correspond to it as ignorant. It excludes all other forms of knowledge that do not correspond to the epistemic charter as conceived by positivist science.
The second is based on the “monoculture of linear time” which is a logic according to which history has only one meaning and only one direction. Also, it holds as backward everything that is asymmetrical in relation to what is considered advanced by Western modernity.
The third is that of the “monoculture of the naturalization of differences”. It consists of classifying populations by racial or gender categories in order to naturalize the hierarchies from which relations of domination result.
The fourth refers to a logic of the “dominant scale”. In Western modernity, the dominant scale is formalized through universalism and globalization. They produce a non-existence that takes the form of the particular or the local.
The last is based on the “monoculture of the criteria of capitalist productivity”. It makes economic growth an indisputable rational objective. Thus, the unproductive becomes a non-existence.
Epistemological alternatives
Boaventura seeks to develop a new epistemology capable of favoring the egalitarian theoretical dialogue between the knowledge of the North and the knowledge of the South. Consequently, the notion of sociology of emergences arises.
Sociology of emergences
The sociology of emergences explores the possible alternatives to the logics of production of absences. It proposes, as a solution to monocultures, ecologies that would make present what is perceived as absent. For example, faced with the monoculture of knowledge and rigour, it proposes the ecology of knowledge, where an infinity of diversified knowledge co-exists, without hierarchy or privileges, without being separated. This form of ecology is an approach that allows us to think about epistemological, political and economic pluralism. It correlates to the epistemology of the link, which is a way of creating sociological knowledge devoid of indifference, marks of epistemological privileges and the logic of erasure.
Epistemology of the South
The sociology of absences and the sociology of emergences are two complementary concepts that make it possible to constitute an alternative that Boaventura calls “the epistemology of the South”. It is “a new production and evaluation of knowledge or valid knowledge, scientific or not”. In other words, it is “new relations between different types of knowledge, based on the practices of classes and social groups that have systematically suffered from the inequalities and discriminations of capitalism and colonialism”. This epistemology is based on two postulates. According to the first, the understanding of the world goes far beyond Western knowledge of the world. As for the second, it implies that the diversity of the world is infinite. It seeks recognition for non-scientific knowledge along with scientific knowledge that is developed through "non-extractive methodologies with a view to contributing to the ecology of knowledge". It promotes the idea of "knowing with the other, and not about the other", pleading for an inverted process of knowledge diffusion where "instead of transferring it from the university to society, it is now a question of bringing non-scientific knowledge from outside the university inside of its walls to foster dialogues and intercultural translation, and thus strengthen social struggles against domination".
It should be clarified that this epistemology is not a claim in favor of a geographical region. The concept "South", here, is not synonymous with a geographical entity. Rather, it is understood as a metaphor for indicating the human suffering caused by the dominant world order.
Moreover, this epistemology corresponds to the epistemological, ethical and political ideal of the notion of cognitive justice as interpreted by the open science movement.
See also
Decolonization of knowledge
Cognitive justice
References
Further reading
TAMAYO, J. J. (2019). Boaventura de Sousa Santos: Sociología de las ausencias y de las emergencias desde las epistemologías del Sur / Boaventura de Sousa Santos: sociologies of absences and emergencies from the South epistemologies. Utopía y Praxis Latinoamericana, 24(86), .
Silva, R. R. C. C., & Neto, L. M. (2016). Social Management from a Critical View of the Sociology of Absences and Sociology of Emergences (Boaventura de Santos Sousa). Administração Pública e Gestão Social, 8(1), .
Machado, C. J. S., Mello, M. B. C. d., & Branquinho, F. (2012). A theoretical approach between the assumptions of ideal sustainability and the Sociology of Absences by Boaventura Sousa Santos. Revista brasileira de gestão e desenvolvimento regional, 8(1), .
Decolonization
Social epistemology
Critical theory | Sociology of absences | [
"Technology"
] | 1,779 | [
"Social epistemology",
"Science and technology studies"
] |
71,505,299 | https://en.wikipedia.org/wiki/Fabimycin | Fabimycin is an newly developed antibiotic candidate which is effective against gram-negative bacterias, an unusually problematic class of bacteria that uses thicker cell walls and molecular efflux pumps to protect themselves by preventing the antibiotics reaching inside the cells.
Antibiotic resistance
Global deaths attributable to antimicrobial resistance (AMR) numbered 1.27 million in 2019. That year, AMR may have contributed to 5 million deaths and one in five people who died due to AMR were children under five years old. The European Centre for Disease Prevention and Control calculated that in 2015 there were 671,689 infections in the EU and European Economic Area caused by antibiotic-resistant bacteria, resulting in 33,110 deaths. Most were acquired in healthcare settings.
History
Researchers modified the structure of Debio-1452, an under-development antibiotic that is active against gram positive bacteria, and its derivative, which is moderately effective against non-resistant gram-negative bacteria. The drug inhibits the bacterial enzyme FabI, which is an important enzyme in bacterial fatty acid biosynthesis. Clinical trials targeting the enzyme for use in S. aureus (Gram +ve) infections have reached Phase 2 inhibitors.
Fabimycin was tested in mice against more than 200 colonies of resistant bacteria, across 54 strains of E. coli, Klebsiella pneumoniae and Acinetobacter baumannii. It cleared up pneumonia and urinary tract infections, pushing bacteria levels lower than before infection in mouse models.
Further, it did not affect some types of commensal bacteria present in the gut microbiome.
See also
Multiple drug resistance
Methicillin-resistant Staphylococcus aureus
References
attribution This page contains text copyrighted with a CC-BY-4.0 license from European Centre for Disease Prevention and Control
Antibiotics
Benzofurans
Lactams
Carboxamides
Pyridines
Azepanes
Amines | Fabimycin | [
"Chemistry",
"Biology"
] | 403 | [
"Biotechnology products",
"Functional groups",
"Antibiotics",
"Amines",
"Biocides",
"Bases (chemistry)"
] |
71,506,226 | https://en.wikipedia.org/wiki/Sean%20Smith%20%28chemist%29 | Sean Smith is the director of NCI Australia with a conjoint position of professor of computational nanomaterials science and technology at the Australian National University (ANU).
Education and research
Smith received a BSc and PhD in chemistry at University of Canterbury in Christchurch, New Zealand before postdoctoral work at University of California, Berkeley (1991-1993) and the University of Göttingen (Humboldt Fellow 1989–1991).
In 1993 he started work at the University of Queensland, eventually heading up the Computational Reaction Dynamics Group before moving on to Oak Ridge National Laboratory in 2011 where he was the director of the Center for Nanophase Materials Sciences. After leaving Oak Ridge in 2017 Smith moved to the University of New South Wales where he founded the Integrated Materials Design Centre.
Smith left the University of New South Wales at the end of 2017 to become director of NCI Australia and professor of computational nanomaterials science and technology at Australian National University.
Awards and honours
Fellow of the Institution of Chemical Engineers (2015)
Bessel Research Award of the German Alexander von Humboldt Foundation (2006)
Fellow of the American Association for the Advancement of Science (2012)
Fellow of the Royal Australian Chemical Institute (1998)
Le Fevre Memorial Prize of the Australian Academy of Science (1998)
Rennie Memorial Medal of the Royal Australian Chemical Institute (1994)
Selected publications
References
External links
Academic profile at ANU
Computational chemists
University of Canterbury alumni
21st-century Australian chemists | Sean Smith (chemist) | [
"Chemistry"
] | 289 | [
"Computational chemistry",
"Theoretical chemists",
"Computational chemists"
] |
71,506,875 | https://en.wikipedia.org/wiki/Goodman%27s%20conjecture | Goodman's conjecture on the coefficients of multivalent functions was proposed in complex analysis in 1948 by Adolph Winkler Goodman, an American mathematician.
Formulation
Let be a -valent function. The conjecture claims the following coefficients hold:
Partial results
It's known that when , the conjecture is true for functions of the form where is a polynomial and is univalent.
External sources
Complex analysis
Conjectures | Goodman's conjecture | [
"Mathematics"
] | 80 | [
"Unsolved problems in mathematics",
"Mathematical problems",
"Conjectures"
] |
71,507,666 | https://en.wikipedia.org/wiki/Path%20space%20%28algebraic%20topology%29 | In algebraic topology, a branch of mathematics, the based path space of a pointed space is the space that consists of all maps from the interval to X such that , called based paths. In other words, it is the mapping space from to .
A space of all maps from to X, with no distinguished point for the start of the paths, is called the free path space of X. The maps from to X are called free paths. The path space is then the pullback of along .
The natural map is a fibration called the path space fibration.
See also
mapping space
References
Further reading
https://ncatlab.org/nlab/show/path+space
Algebraic topology | Path space (algebraic topology) | [
"Mathematics"
] | 144 | [
"Topology stubs",
"Fields of abstract algebra",
"Topology",
"Algebraic topology"
] |
71,507,939 | https://en.wikipedia.org/wiki/Hafnium%20carbonitride | Hafnium carbonitride (HfCN) is an ultra-high temperature ceramic (UHTC) mixed anion compound composed of hafnium (Hf), carbon (C) and nitrogen (N).
Ab initio molecular dynamics calculations have predicted the HfCN (specifically the HfC0.75N0.22 phase) to have a melting point of 4,110 ± 62 °C (), highest known for any material. Another approach based on the artificial neural network machine learning pointed towards a similar composition — HfC0.76N0.24. Experimental testing conducted in 2020 has confirmed a melting point above , substantiating earlier predictions made with atomistic simulations in 2015.
Properties
The HfCxN1−x has been assessed to possess the following properties:
Thermal conductivity:
19–24 W·m−1·K−1 at room temperature,
32–39 W·m−1·K−1 at high temperature and with increased nitrogen content.
Electrical conductivity: (149×104)–(213×104) Ω−1 m−1
Plasticity limit:
Fusion enthalpy:
Flexural strength:
638 ± 28 MPa at room temperature,
324 MPa at ,
139 MPa at ,
100 MPa at .
Fracture toughness: 6.73 ± 0.07 MPa·m1/2, 4.7 ± 0.3 MPa·m1/2
Vickers hardness: , 21.3 ± 0.55 GPa ()
References
Hafnium compounds
Carbides
Nitrides
Mixed anion compounds
Refractory materials | Hafnium carbonitride | [
"Physics",
"Chemistry"
] | 327 | [
"Matter",
"Mixed anion compounds",
"Refractory materials",
"Materials",
"Ions"
] |
71,508,609 | https://en.wikipedia.org/wiki/Category%20of%20compactly%20generated%20weak%20Hausdorff%20spaces | In mathematics, the category of compactly generated weak Hausdorff spaces, CGWH, is a category used in algebraic topology as an alternative to the category of topological spaces, Top, as the latter lacks some properties that are common in practice and often convenient to use in proofs. There is also such a category for the CGWH analog of pointed topological spaces, defined by requiring maps to preserve base points.
The articles compactly generated space and weak Hausdorff space define the respective topological properties. For the historical motivation behind these conditions on spaces, see Compactly generated space#Motivation. This article focuses on the properties of the category.
Properties
CGWH has the following properties:
It is complete and cocomplete.
The forgetful functor to the sets preserves small limits.
It contains all the locally compact Hausdorff spaces and all the CW complexes.
An internal Hom exists for any pairs of spaces X and Y; it is denoted by or and is called the (free) mapping space from X to Y. Moreover, there is a homeomorphism
that is natural in X, Y, and Z. In short, the category is Cartesian closed in an enriched sense.
A finite product of CW complexes is a CW complex.
If and are pointed spaces, then the smash product of them exists. The (based) mapping space from to consists of all base-point-preserving maps from to and is a closed subspace of the mapping space between the underlying spaces without base points. It is a based space with the base point the unique constant map. Moreover, for based spaces , , and , there is a homeomorphism
that is natural in , , and .
Notes
References
Further reading
The CGWH category, Dongryul Kim 2017
Algebraic topology
Categories in category theory | Category of compactly generated weak Hausdorff spaces | [
"Mathematics"
] | 369 | [
"Mathematical structures",
"Algebraic topology",
"Topology stubs",
"Fields of abstract algebra",
"Topology",
"Category theory",
"Categories in category theory"
] |
71,509,607 | https://en.wikipedia.org/wiki/Pterocladiophilaceae | The Pterocladiophilaceae is a small family of red algae containing 2 (or 3) genera of thallus parasitic algae.
Taxonomy
The family Pterocladiophilaceae was originally established by Fan & Papenfuss (1959: 38) to accommodate their newly named genus and species, Pterocladiophila hemisphaerica, a parasite on Pterocladia lucida in New Zealand. This parastitic alga, which differs from all other parasitic red algae in having zonately divided tetrasporangia, was tentatively assigned to the Cryptonemiales. Fredericq & Hommersand (1990a), as an outgrowth of their detailed morphological study of Holmsella pachyderma , a parasite algae feeding on Gracilaria and Gracilariopsis in Great Britain and Ireland that had been assigned to the Choreocolacaceae family, noted that it had a lot of similarities among Holmsella , Gelidiocolax , and Pterocladiophila. These various similarities include the pattern of vegetative cell division, catenate (chain-like) spermatangia, two-celled carpogonial branch, and the apparent absence of an auxiliary cell. Fredericq & Hommersand grouped these three genera in the Pterocladiophilaceae family, arguing that the cruciate division of tetrasporangia in Gelidiocolax and Holmsella was not a serious objection to uniting these genera with Pterocladiophila. Moreover, on the basis of certain features of spermatangial initiation, gonimoblast development, and the pattern of concavo-convex divisions of apical and cortical cells, they assigned the family to the Gracilariales.
Pterocladiophila hemisphaerica has shown due to Dna analysis, to be within the Ceramiales order, but the parasite was grouped with support as sister to the Gracilariales order.
Genera
As accepted by GBIF;
Gelidiocolax N.L.Gardner, 1927 (2)
Holmsella Sturch, 1926 (2)
Figures in brackets are approx. how many species per genus.
Note, Pterocladiophila is not accepted as a species by the GBIF. It has a sole species Pterocladiophila hemisphaerica , that was originally described from New Zealand, and has also been recorded from the Caribbean (Stegenga and Vroman 1986). The species is accepted by AlgaeBase, and WoRMS.
Description and ecology
They feed on members of the Gelidiaceae family or Gracilaria species of algae, forming small, white to pigmented, hemispherical to verrucose, pustules (raised structure containing necrotic inflammatory cells). They basally penetrate the tissue of the host and protrude above the host's surface.
They are minute, generally more or less spherical (in shape), They have an internal structure of branched, endophytic, rhizoidal filaments pit-connected to host cells, and the pustules of outer, anticlinal, cortical chains and inner larger-celled, multinucleate, medullary cells with numerous secondary pit-connections.
Reproduction is carried out by Gametangial thalli dioecious. The Carpogonial branches (female parts) are 2-celled, borne on a supporting cell in a cortical filament, with a straight trichogyne (slender, hair-like cell which receives the fertilizing particles). The auxiliary cells are absent; fertilized carpogonium possibly fusing with adjacent vegetative cells and developing the gonimoblast directly, consisting of horizontal filaments fusing with vegetative cells and clusters of erect filaments bearing chains of carposporangia, interspersed among cortical filaments; pericarp absent. Spermatangia formed in chains from surface cortical cells, cut off by intercalary divisions from initial cells.
Tetrasporangia scattered in the cortex or in pits, cruciately or zonately divided. The spermatangia are produced in chains, cut off transversely at upper end of spermatangial parent cell.
References
Other sources
Fredericq, S. & Hommersand, M.H. (1990a). Morphology and systematics of Holmsella pachyderma (Pterocladiophilaceae, Gracilariales). Br. phycol. J. 25, 39–51.
Red algae families
Edible algae
Gracilariales | Pterocladiophilaceae | [
"Biology"
] | 980 | [
"Edible algae",
"Algae"
] |
71,510,290 | https://en.wikipedia.org/wiki/Epsilon%20Eta | Epsilon Eta (), also known as Ep Eta, is an American professional gender-inclusive fraternity for students interested in careers in environmental science and sustainability. Founded in 2006 at the University of North Carolina at Chapel Hill, it is the first nationwide environmental fraternity in the United States. The fraternity has grown to include chapters across the United States. There is no national organization as of December 2024.
History
Liza Schillo, an undergraduate student at the University of North Carolina at Chapel Hill, founded Epsilon Eta Environmental Honors Fraternity in 2006. It was established as a professional, gender-inclusive fraternity for individuals seeking post-graduate positions in the environmental field. The fraternity's mission is "to promote a healthy and sustainable environment and connect students to industries, community service, and academia in pursuit of these goals." Epsilon Eta has three pillars: academics, community, and service.
Beta chapter at the University of Michigan was conceived by Julia Austin, Zach Fogel, Daly Kleaveland, and Julia Wang in the summer of 2014. They recruited Caitlin Climes, Sam McMullen, Josh Musicant, Dylan Nelson, and Matt Sehrsweeney to complete the group of nine founders. Beta chapter was chartered and initiated its first class in 2015.
Originally meeting in a freshman environmental earth sciences seminar, nine sophomores formed an Epsilon Eta colony at the University of Pennsylvania in the October 2015; the colony later became Gamma chapter. Other chapters followed in 2016 and 2017, with North Carolina State University becoming the seventh official chapter in 2017. The twelfth chapter was established at the University of Delaware in 2018. This was followed by chapters at the University of Illinois Urbana-Champaign and San Diego State University in 2018, and Boston University and University of Maryland, College Park in 2019.
By 2000, the Alpha chapter had initiated ninety members, and an executive committee was established to oversee the national fraternity. However, in the fall of 2020 three of Alpha chapter's former members publicly criticized the group "for fostering white supremacy." The fraternity's executive board and Alpha's members decided to close the chapter in September 2020. The Daily Tar Heel shared the chapter's statement: "As a historically exclusive and majority-white institution with semblances of Greek life, we have contributed to the preservation of white supremacy on UNC-Chapel Hill’s campus. Our actions have marginalized and silenced BIPOC voices. To address these injustices, we view abolition as the most direct course of action to dismantle white supremacy."
Despite this setback, new chapters formed at Virginia Commonwealth University in 2020, the University of Arizona in 2022, and the University of Virginia in 2023. The Alpha chapter was re-established at the University of North Carolina in September 2022 by Tayton Alvis, Sarah Masters, Zachary Miller, Gregory Mink, and Sanjana Venkatraman.
Symbols
The Greek letters Epsilon Eta stand for Science and Morality. Epsilon Eta's colors are Kelly green, Navy blue, and Sky blue. Its original emblem is a sky-blue shield edged in navy blue and decorated with a white three-pronged geometric knot entwined around an oak tree. A later variation of the emblem features a light green shield with a dark green emblem of leaf veins on the right half and an overlaying tree in dark green across the center.
Membership
Membership to Epsilon Eta is not limited by major but initiates must be interested in the environmental field. The fraternity's members are divided into regular, associate, and alumni. Associate members are undergraduates who fail to meet the GPA or service hour requirements. Regular members and alumni may wear the fraternity's insignia.
Instead of "Bigs" and "Littles" like traditional Greek Life, some Epsilon Eta chapters use the terms "Oaks" and "Saplings".
Chapters
Following are the collegiate chapters of Epsilon Eta. Active chapters are indicated in bold. Inactive chapters are indicated in italic.
Notes
See also
Professional fraternities and sororities
References
Student organizations established in 2006
2006 establishments in North Carolina
Professional fraternities and sororities in the United States
Honor societies
Environmental science
University of North Carolina at Chapel Hill
Student societies in the United States | Epsilon Eta | [
"Environmental_science"
] | 853 | [
"nan"
] |
71,510,397 | https://en.wikipedia.org/wiki/Cell%20extrusion | Cell extrusion, discovered in 2001, is a process conserved in epithelial from humans to sea sponge to seamlessly remove unwanted or dying cells while maintaining the integrity of the epithelial barrier. If cells were to die without extrusion, gaps would be created, compromising the epithelia's function. While cell targeted to die by apoptotic stimuli extrude to prevent gaps from forming, most cells die as a result of extruding live cells. To maintain epithelial cell number homeostasis, live cells extrude when they become too crowded.
Function
Cell extrusion enables the removal of less fit and excess cells from the epithelia and endothelia. Apoptotic epithelial cell extrusion was first discovered as a way to prevent gaps when cell die within an epithelial layer. In vertebrates, most cells extrude out apically into the lumen, however, during fruit fly development, they extrude basally, back into the tissue the epithelia encase where they are engulfed.
During homeostasis, live cell extrusion drives most epithelial cell death when too many cells accumulate. To maintain constant cell numbers, crowding signals some cells to extrude, which then later die through anoikis, or death due to lost of survival signaling, derived from the underlying matrix. Live cell extrusion is essential for maintaining constant cell densities and preventing neoplasms, as its disruption causes masses to rapidly form.
Triggers
Various factors such as apoptosis, overcrowding, pathogens and replicative stress can trigger extrusion from epithelia. Additionally, cells transformed with oncogenic mutations such as HRAS and Src can be ejected from epithelia by a similar extrusion process called Epithelial Defense Against Cancer (EDAC).
Signaling controlling extrusion
The rate limiting step for all types of cell extrusion discovered thus far is the production of the bioactive lipid, Sphingosine 1-Phosphate (S1P), which then binds the G-protein-coupled receptor, S1P2 to trigger Rho-mediated actin and myosin contraction at the base of the cell, propelling the cell out apically. Trafficking of S1P to the basolateral plasma membrane requires microtubules, p115 RhoGEF and the plus-ended microtubule binding tumor suppressor Adenomatous Polyposis Coli (APC). While the S1P-S1P2-Rho-actin/myosin axis apparently controls all extrusions, this axis can be activated by different signaling, depending on the stimulus. Apoptotic extrusion may activate S1P simply through caspase activation. However, live cell extrusion is activated by crowding dependent activation of the stretch-activated cation channel Piezo1. Extrusion triggered by replicative stress or by cell competition requires p53 activation.
Pathologies stemming from defective extrusion
Cancer
Disruption of extrusion not only leads to rapid formation of masses, a number of oncogenic mutations that drive aggressive cancers can hijack extrusion signaling in various ways to cause mass formation, disrupted barrier function, and aberrant Basal Cell Extrusion (BCE). While most cells extrude apically out of the epithelia organs encase, BCE drives cells in the opposite direction—basally, which can enable them to invade through the underlying stroma. Cells transformed with KRas, a driver of pancreatic, and some types of lung and colon cancer, have unregulated autophagy, which degrades S1P and prevents apical extrusion. Instead, cells form masses at sites where they would normally extrude and, at completely separate sites invade by BCE. Importantly, as they invade, BCE also causes the mechanical pinching off of their apical surfaces, which include epithelial determinants, thereby causing the cells to essentially partially de-differentiate. Thus, oncogenic transformation can cause cells to mechanically de-differentiate and invade by hijacking a process that normally drives cell death. Similarly, mutations in APC mis-target S1P, also causing BCE. Moreover, pancreatic cancers and some types of colon and lung cancer vastly down regulate S1P2. Rescue of S1P2 alone is sufficient to reduce orthotopic pancreatic cancer and metastases in a mouse model.
Asthma
Whereas too little extrusion can lead to cancer, too much can drive inflammatory disease. Typically crowding of 1.6-fold causes live cells to extrude during homeostatic turnover. When epithelia experience pathological crowding, as airway epithelial do during an asthma attack, they can extrude at such high rates that it destroys the barrier they should provide. This then mechanically causes the ensuing inflammation and hyper-susceptibility to infections that can follow an asthma attack. Because of this, blocking extrusion during an asthma attack may offer a new way to prevent this inflammatory period and potentially future attacks.
References
Histology
Epithelial cells | Cell extrusion | [
"Chemistry"
] | 1,074 | [
"Histology",
"Microscopy"
] |
71,511,082 | https://en.wikipedia.org/wiki/HD%20182509 | HD 182509, also designated as HR 7370, is an orange hued star located in the southern constellation Telescopium. It has an apparent magnitude of 5.69, making it faintly visible to the naked eye if viewed under ideal conditions. Parallax measurements place the object at a distance of 635 light years. It has a poorly constrained heliocentric radial velocity of , indicating that it is drifting towards the Solar System.
HD 182509 has a stellar classification of K4 III, indicating that it is a red giant. Gaia DR3 stellar evolution models place it on the red giant branch. It has 1.12 times the mass of the Sun but has expanded to 32.6 times its girth. It shines with a luminosity of from its enlarged photosphere at an effective temperature of . HD 182509 iron abundance is 95% that of the Sun, placing it at solar metallicity. Like most giants, it spins slowly with a projected rotational velocity of .
HD 182466 is a high proper motion star located away along a position angle of 236°. Eggleton and Tokovonin (2008) list the pair as a binary star. However, its parallax and proper motion indicate that it is instead a foreground object. Components C and D are instead faint optical background objects, while the E component is probably non-existent.
References
K-type giants
Telescopium
182509
CD-54 08308
095690
7370
Telescopii, 59
Multiple stars | HD 182509 | [
"Astronomy"
] | 318 | [
"Telescopium",
"Multiple stars",
"Sky regions",
"Constellations"
] |
71,511,293 | https://en.wikipedia.org/wiki/Information%20and%20Organization | Information and Organization is an academic journal related to the relationship between ICT and different social consequences experienced by different individuals, stakeholders and socieities. Empirical research and relevant theories are published in this journal, while some future research directions in the same area are also offered.
Currently, Information and Organization is being listed as A* under the academic journal list of Australian Business Dean Council (ABDC).
References
Business and management journals
Information systems journals
English-language journals | Information and Organization | [
"Technology"
] | 92 | [
"Information systems journals",
"Information systems"
] |
71,511,975 | https://en.wikipedia.org/wiki/2022%20Oder%20environmental%20disaster | During the summer of 2022, a mass mortality event involving fish, beavers, clams, crayfish and other wildlife occurred in the Oder river.
Over 100 tonnes of dead fish were removed from the Polish section of the river, and a further 35 tonnes from German sections, causing concern that the water was poisoned.
At first the cause was not clear, theories included the effects of the summer heat and lower water levels due to the European drought, reduced oxygen levels due to the heat and nutrient loading, a spike in oxygen levels due to the introduction of an oxidizing agent, and pollution by chemicals including mercury, mesitylene, salts or other sewage, as well as the possibility of an algal bloom. It was later determined to be an algal bloom, which was made possible by the discharge of saline industrial wastewater into the river on the Polish side, is now considered the probable cause of the disaster.
The Polish authorities were slow to react, causing a scandal and resulting in the dismissal of officials responsible for water management and environmental protection. A reward of 1 million zlotys (about €222,000, as of September 2023) was offered for information about possible culprits.
Background
The Oder flows through the city of Ostrava, across the Czech–Polish border, terminates the Gliwice Canal, passes through Lower Silesia including the city of Wrocław, and farther forms the German–Polish border until it flows into the Baltic Sea. It is engineered to carry heavy barge traffic.
Decades ago, the Oder river was extremely polluted before reaching Wrocław due to the heavy industrialization in Ostrava, Upper Silesia (connected through the Canal and the Kłodnica river having many large coal mines around), and Lower Silesia. Large chemical factories are in Kędzierzyn-Koźle at the Canal. Europe's largest coke (fuel) plant is located in Zdzieszowice just above Opole. Nowa Ruda (the 21st most polluted city in the European Union in 2015) with another coal mine lies in the mountains in the basin of Eastern Neisse, another of Oder's tributaries. The Jelcz factory is located near Oława just above Wrocław while a chemical plant - just below in Brzeg Dolny. Further west of Wrocław, in the basin of the Kaczawa tributary, lies Legnica with large copperworks KGHM and factories, whereas copper ore is mined in nearby Lubin. In the basin of the Bystrzyca (Oder) tributary, south of Legnica, there is the sizable city of Walbrzych with more coal mines, a coke plant, chemical and textile factories, which use chemical dyes and large amounts of water. In the basin of the Lusatian Neisse tributary, along which the Polish-German border is extended south of Oder, and south of Görlitz, lies the Turów coal mine supplying the nearby Turów Power Station with lignite often containing toxic heavy metals and sulfur.
As recently as 2012, the Oder transported over 100 tonnes of heavy metals in its waters into the Baltic Sea.
Discovery
Fish die-offs were reported by anglers around Oława as early as March 2022. Large die-offs then started again at the end of July 2022. On 11 August 2022, volunteers and anglers removed at least 10 tonnes of dead fish from the stretch of the river north of Oława in southwest Poland. The discovery was made by local fishermen, as opposed to any regulatory or testing body. Other dead animals included beavers and birds.
Cause
Early on, it was suspected that the cause of the die-off was poisoning by an unknown toxic substance. Water samples taken on 28 July showed a high probability of the presence of the contaminant mesitylene, although the Polish government claimed that it was not present on samples taken after 1 August.
A German testing lab had found traces of mercury, but the Polish government reported that their tests determined that mercury poisoning was not the cause of the die-off. According to them, it was caused by golden algae (likely Prymnesium parvum, which prefer warm salty alkaline waters). Researchers at the Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB) have offered an interim hypothesis that the cause was golden algae.
According to the Brandenburg Environment Minister, Axel Vogel, German laboratories believe the fish deaths may have been the result of large amounts of salt in the water.
A February 2023 European Commission JRC report, which built on previous formal reports from both Germany and Poland concluded: "The direct cause of the ecological disaster in the Oder River was prymnesin toxins from Prymnesium parvum algae."
Water quality testing
Data gained via an automatic water quality measuring station in Frankfurt an der Oder (over downstream) indicated that from 4 August 2022 the electrical conductivity had climbed anomalously. This data also showed a large change in other water quality parameters. On 7 August 2022, dissolved oxygen, electrical conductivity, and UV absorption almost doubled; nitrate levels plummeted and chlorophyll increased by a factor of ten. The water also became more turbid and its pH increased to about 8.8–9.2. This could indicate increased levels of salt in the river, consistent with the conclusion that since 7 August 2022 a huge amount of salt reached the town. The pH changes could also support the 'Golden Algae hypothesis'.
Implications
The ecosystem of the river was severely damaged. Scientists are concerned that if the damage was caused by mercury poisoning, detrimental effects could be long term as mercury is a persistent heavy metal. There are also potential serious health consequences for humans.
Reaction
The Prime Minister of Poland Mateusz Morawiecki was put under pressure to act and fired two government officials as a result (the head of the water authority, , , and the head of the environmental authority, , ). This in turn caused internal rifts in the ruling Law and Justice party.
Local residents reacted negatively to the government's actions, and, with the state television avoiding reporting on the subject, widespread allegations of a government cover-up began. Criticism also fell on the local voivodes.
The Polish opposition blamed the Polish government for reacting slowly to the developing situation, and downplaying the scale of the problem. The government said the perpetrators would be severely punished, while blaming opposition politicians, in particular Donald Tusk and Rafał Trzaskowski, for exaggerating the issue. The government media has compared the situation to other previous minor and unrelated events in Warsaw and Gdańsk, where the opposition Civic Platform holds power. On 12 August, the deputy minister of infrastructure, , blamed the opposition and the ecologists, and stated that the river was safe to enter, and fishing is allowed. Krystyna Pawłowicz, a Eurosceptic member of the Law and Justice party, has publicly suggested that other countries may be responsible for the contaminations.
Some anglers fear that fish might never return to the river, and Steffi Lemke, the German Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection, called the situation a catastrophe and a shocking ecological disaster. German officials have also complained about the lack of communication from the Polish officials.
Poles are very critical of government reactions, according to polls, in which more than 60% of responders said that they "disapprove of the government's response to the environmental disaster on the Oder River".
References
External links
Summary including timeline and a map related to the event (Polish)
2022 in the environment
2022 disasters in Germany
2022 disasters in Poland
July 2022 events in Germany
July 2022 events in Poland
August 2022 events in Germany
August 2022 events in Poland
Chemical disasters
Environmental disasters in Poland
Fishing disasters
Waste disposal incidents
Germany–Poland relations
2022 environmental disaster
Pollution events in 2022
Industrial accidents and incidents in Poland | 2022 Oder environmental disaster | [
"Chemistry"
] | 1,624 | [
"Chemical accident",
"Chemical disasters"
] |
71,514,588 | https://en.wikipedia.org/wiki/Approximate%20fibration | In algebraic topology, a branch of mathematics, an approximate fibration is a sort of fibration such that the homotopy lifting property holds only approximately. The notion was introduced by Coram and Duvall in 1977.
A manifold approximate fibration is a proper approximate fibration between manifolds. Some authors believe that manifold approximate fibrations are the "correct bundle theory for topological manifolds and singular spaces".
References
Further reading
nLab - approximate fibration
Algebraic topology | Approximate fibration | [
"Mathematics"
] | 101 | [
"Topology stubs",
"Fields of abstract algebra",
"Topology",
"Algebraic topology"
] |
71,514,674 | https://en.wikipedia.org/wiki/Ant%20supercolony | An ant supercolony is an exceptionally large ant colony, consisting of a high number of spatially separated but socially connected nests of a single ant species (meaning that the colony is polydomous), spread over a large area without territorial borders. Supercolonies are typically polygynous, containing many egg-laying females (queens or gynes). Workers and queens from different nests within the same supercolony can freely move among the nests, and all workers cooperate indiscriminately with each other in collecting food and care of the brood, and show no apparent mutual aggressive behavior.
As long as suitable unoccupied space with sufficient resources is available, supercolonies expand continuously through budding, as queens together with some workers migrate over short distances and establish a new connected nest. The supercolony can also expand over long distances through jump-dispersal, potentially ranging between continents. Jump-dispersal usually occurs unintentionally through human-mediated transport. A striking example of an ant species forming supercolonies across continents is the Argentine ant (Linepithema humile). The also highly invasive red imported fire ant (Solenopsis invicta) and Solenopsis geminata additionally use classic mating flights, thus using three primary modes of dispersal. Out of some 14,000 described ant species, supercolonialism is found in less than 1% of all ants.
In general, ants that form supercolonies are invasive and harmful in the non-native environments. While not all supercolonial species are invasive and not all invasive ants are dominant, supercolonies are usually associated with invasive populations. Some invasive species are known to form supercolonies in their native habitat as well. In their native range, relatively small supercolonies are observed, whereas they are much larger, dominant and a threat for ecological diversity in their invasive range. Exceptions of species that form supercolonies without being invasive are mainly found in the genus Formica.
Although supercolonies are mainly observed in relatively few ant species, similar unicolonial populations are also found in some species of the termite genus Reticulitermes.
Unicoloniality versus supercoloniality
Initially, it was hypothesized that unicoloniality is a characteristic of certain ant species in which all workers of that species are amicable, whatever their nest of origin. So, all members of the species would accept each other, irrespective of the nest of origin and irrespective of the distance between the nests. In contrast, multicoloniality is the common characteristic of ants to show all colonies being aggressive to each other, including different colonies of the same species. A supercolony would be a large aggregation of nests of a species that normally would exhibit multicoloniality, but in the case of a supercolony has all workers from all connected nests being non-aggressive to each other. The Argentine ant (Linepithema humile), forming megacolonies of spatially separate nests, was thought to be a perfect example of
unicoloniality, never exhibiting multicoloniality.
Giraud et al. (2002), however, discovered that L. humile also forms supercolonies that are aggressive to each other, so unicoloniality turned out to be limited. They hypothesized that the difference between supercoloniality and unicoloniality is not clear-cut, but that they are rather points on a continuum between two extremes: multicoloniality with all colonies generally being aggressive to each other, contrasted with unicoloniality with absolute absence of aggression between colonies, and supercoloniality somewhere in between.
Therefore, Pedersen et al. (2006) redefined supercoloniality and unicoloniality as follows:
Supercolony: A colony that contains such a large number of nests that direct cooperative interactions are impossible between individuals in distant nests. There are no behavioral boundaries (aggression) within the supercolony.
Unicolonial: A unicolonial species is one that can form supercolonies. A unicolonial population consists of one or several supercolonies.
They suggest that the success of invasive ants such as L. humile stem from the ecological conditions in the introduced range that allow to dramatically extend the dimension of supercolonies, rather than from a shift in social organization in the invaded habitat.
Supercolonies in termites
Although supercolonies are mainly observed in relatively few ant species, similar unicolonial populations are also found in some species of the termite genus Reticulitermes.
In France, a supercolony of the invasive termite species Reticulitermes urbis was observed, covering about seven hectares, similar to an ant supercolony. Invasive unicolonial metapopulations of Reticulitermes flavipes in Toronto, Canada are described in 2012. They can cover tens of kilometers, number hundreds of thousands or millions of individuals and show lack of intercolony aggression. Especially in urban habitats they form area-wide supercolonies.
Examples
Species known to form supercolonies are: (see also the list on AntWiki)
Anoplolepis gracilipes (yellow crazy ant)
Formica
Formica aquilonia
Formica exsecta
Formica obscuripes
Formica polyctena
Formica yessensis
Iridomyrmex purpureus (meat ant)
Lasius neglectus
Lepisiota
Lepisiota canescens
Lepisiota frauenfeldi
Lepisiota incisa
Linepithema humile (Argentine ant)
Monomorium pharaonis
Myrmica rubra
Nylanderia fulva (tawny crazy ant)
Paratrechina longicornis
Pheidole megacephala
Plagiolepis
Plagiolepis alluaudi (little yellow ant)
Plagiolepis invadens
Plagiolepis pygmaea
Plagiolepis schmitzii
Polyrhachis robsoni
Pseudomyrmex veneficus
Solenopsis
Solenopsis geminata (tropical fire ant)
Solenopsis invicta (red imported fire ant, or RIFA)
Solenopsis richteri (black imported fire ant, or BIFA)
Solenopsis saevissima (pest fire ant)
Tapinoma
Tapinoma darioi
Tapinoma ibericum
Tapinoma magnum
Tapinoma sessile
Technomyrmex albipes Tetramorium alpestre Vollenhovia emeryi Wasmannia auropunctata Formica
A supercolony of Formica obscuripes in the US state of Oregon, consisting of more than 200 nests and an estimated population of 56 million individuals was described in 1997.
The Ishikari supercolony of Formica yessensis on Hokkaido, Japan comprise estimated more than 45,000 nests, more than 300,000,000 workers and more than 1,000,000 queens.
Tapinoma
Three of the four species identified in the `Tapinoma nigerrimum complex´ are known as supercolonial: T. darioi, T. ibericum and T. magnum. Tapinoma nigerrimum is monodomous to moderately polydomous, multicolonial, and supercoloniality is unknown.Tapinoma sessile'' lives in its natural habitat in small colonies. Invaded in urban areas, it exhibits extreme polygyny and polydomy and becomes a dominant invasive pest. Dependent on the season, the number of nests in the colony may alternately fuse into one or a few in winter and grow from spring, to reach maximum nest density in summer. Their early-season population growth is exponential. In general, T. sessile colonies move on a regular basis. They establish trails between nest and food resources, and to colonise new areas.
References
Supercolony
Superorganisms | Ant supercolony | [
"Biology"
] | 1,657 | [
"Superorganisms",
"Symbiosis"
] |
71,514,894 | https://en.wikipedia.org/wiki/Voevodsky%20Institute%20of%20Chemical%20Kinetics%20and%20Combustion | V. V. Voevodsky Institute of Chemical Kinetics and Combustion of the Siberian Branch of the RAS, ICKC SB RAS () is a research institute in Novosibirsk, Russia. It was founded in 1957.
History
The institute was founded in 1957. Its team was formed of scientists led by A. A. Kovalsky and V. V. Voevodsky. In 2002, the number of employees was 284.
Activities
The study of combustion mechanisms in gas and condensed phases, the processes of formation and distribution of aerosols etc. The institute has developed methods for high-resolution radiospectroscopy and methods for the filtration combustion of gases. It created aerosol technologies for the protection of crops and forests.
Awards
The works of the institute staff were awarded the USSR Council of Ministers Prize (1985), the Lenin Prize (1986), two USSR State Prizes (1968, 1988) and the State Prize of the Russian Federation (1994).
References
External links
Институт химической кинетики и горения им. В. В. Воеводского СО РАН. СО РАН.
Research institutes in Novosibirsk
Chemical research institutes
1957 establishments in the Soviet Union
Research institutes established in 1957
Research institutes in the Soviet Union | Voevodsky Institute of Chemical Kinetics and Combustion | [
"Chemistry"
] | 294 | [
"Chemical research institutes"
] |
71,515,213 | https://en.wikipedia.org/wiki/History%20of%20synthetic-aperture%20radar | The history of synthetic-aperture radar begins in 1951, with the invention of the technology by mathematician Carl A. Wiley, and its development in the following decade. Initially developed for military use, the technology has since been applied in the field of planetary science.
Invention
Carl A. Wiley, a mathematician at Goodyear Aircraft Company in Litchfield Park, Arizona, invented synthetic-aperture radar in June 1951 while working on a correlation guidance system for the Atlas ICBM program. In early 1952, Wiley, together with Fred Heisley and Bill Welty, constructed a concept validation system known as DOUSER ("Doppler Unbeamed Search Radar"). During the 1950s and 1960s, Goodyear Aircraft (later Goodyear Aerospace) introduced numerous advancements in SAR technology, many with help from Don Beckerleg.
Independently of Wiley's work, experimental trials in early 1952 by Sherwin and others at the University of Illinois' Control Systems Laboratory showed results that they pointed out "could provide the basis for radar systems with greatly improved angular resolution" and might even lead to systems capable of focusing at all ranges simultaneously.
In both of those programs, processing of the radar returns was done by electrical-circuit filtering methods. In essence, signal strength in isolated discrete bands of Doppler frequency defined image intensities that were displayed at matching angular positions within proper range locations. When only the central (zero-Doppler band) portion of the return signals was used, the effect was as if only that central part of the beam existed. That led to the term Doppler Beam Sharpening. Displaying returns from several adjacent non-zero Doppler frequency bands accomplished further "beam-subdividing" (sometimes called "unfocused radar", though it could have been considered "semi-focused"). Wiley's patent, applied for in 1954, still proposed similar processing. The bulkiness of the circuitry then available limited the extent to which those schemes might further improve resolution.
The principle was included in a memorandum authored by Walter Hausz of General Electric that was part of the then-secret report of a 1952 Dept. of Defense summer study conference called TEOTA ("The Eyes of the Army"), which sought to identify new techniques useful for military reconnaissance and technical gathering of intelligence. A follow-on summer program in 1953 at the University of Michigan, called Project Wolverine, identified several of the TEOTA subjects, including Doppler-assisted sub-beamwidth resolution, as research efforts to be sponsored by the Department of Defense (DoD) at various academic and industrial research laboratories. In that same year, the Illinois group produced a "strip-map" image exhibiting a considerable amount of sub-beamwidth resolution.
Project Michigan
Objectives
A more advanced focused-radar project was among several remote sensing schemes assigned in 1953 to Project Michigan, a tri-service-sponsored (Army, Navy, Air Force) program at the University of Michigan's Willow Run Research Center (WRRC), that program being administered by the Army Signal Corps. Initially called the side-looking radar project, it was carried out by a group first known as the Radar Laboratory and later as the Radar and Optics Laboratory. It proposed to take into account, not just the short-term existence of several particular Doppler shifts, but the entire history of the steadily varying shifts from each target as the latter crossed the beam. An early analysis by Dr. Louis J. Cutrona, Weston E. Vivian, and Emmett N. Leith of that group showed that such a fully focused system should yield, at all ranges, a resolution equal to the width (or, by some criteria, the half-width) of the real antenna carried on the radar aircraft and continually pointed broadside to the aircraft's path.
Technical and scientific basis
The required data processing amounted to calculating cross-correlations of the received signals with samples of the forms of signals to be expected from unit-amplitude sources at the various ranges. At that time, even large digital computers had capabilities somewhat near the levels of today's four-function handheld calculators, hence were nowhere near able to do such a huge amount of computation. Instead, the device for doing the correlation computations was to be an optical correlator.
It was proposed that signals received by the traveling antenna and coherently detected be displayed as a single range-trace line across the diameter of the face of a cathode-ray tube, the line's successive forms being recorded as images projected onto a film traveling perpendicular to the length of that line. The information on the developed film was to be subsequently processed in the laboratory on equipment still to be devised as a principal task of the project. In the initial processor proposal, an arrangement of lenses was expected to multiply the recorded signals point-by-point with the known signal forms by passing light successively through both the signal film and another film containing the known signal pattern. The subsequent summation, or integration, step of the correlation was to be done by converging appropriate sets of multiplication products by the focusing action of one or more spherical and cylindrical lenses. The processor was to be, in effect, an optical analog computer performing large-scale scalar arithmetic calculations in many channels (with many light "rays") at once. Ultimately, two such devices would be needed, their outputs to be combined as quadrature components of the complete solution.
A desire to keep the equipment small had led to recording the reference pattern on 35 mm film. Trials promptly showed that the patterns on the film were so fine as to show pronounced diffraction effects that prevented sharp final focusing.
That led Leith, a physicist who was devising the correlator, to recognize that those effects in themselves could, by natural processes, perform a significant part of the needed processing, since along-track strips of the recording operated like diametrical slices of a series of circular optical zone plates. Any such plate performs somewhat like a lens, each plate having a specific focal length for any given wavelength. The recording that had been considered as scalar became recognized as pairs of opposite-sign vector ones of many spatial frequencies plus a zero-frequency "bias" quantity. The needed correlation summation changed from a pair of scalar ones to a single vector one.
Each zone plate strip has two equal but oppositely signed focal lengths, one real, where a beam through it converges to a focus, and one virtual, where another beam appears to have diverged from, beyond the other face of the zone plate. The zero-frequency (DC bias) component has no focal point, but overlays both the converging and diverging beams. The key to obtaining, from the converging wave component, focused images that are not overlaid with unwanted haze from the other two is to block the latter, allowing only the wanted beam to pass through a properly positioned frequency-band selecting aperture.
Each radar range yields a zone plate strip with a focal length proportional to that range. This fact became a principal complication in the design of optical processors. Consequently, technical journals of the time contain a large volume of material devoted to ways for coping with the variation of focus with range.
For that major change in approach, the light used had to be both monochromatic and coherent, properties that were already a requirement on the radar radiation. Lasers also then being in the future, the best then-available approximation to a coherent light source was the output of a mercury vapor lamp, passed through a color filter that was matched to the lamp spectrum's green band, and then concentrated as well as possible onto a very small beam-limiting aperture. While the resulting amount of light was so weak that very long exposure times had to be used, a workable optical correlator was assembled in time to be used when appropriate data became available.
Although creating that radar was a more straightforward task based on already-known techniques, that work did demand the achievement of signal linearity and frequency stability that were at the extreme state of the art. An adequate instrument was designed and built by the Radar Laboratory and was installed in a C-46 (Curtiss Commando) aircraft. Because the aircraft was bailed to WRRC by the U. S. Army and was flown and maintained by WRRC's own pilots and ground personnel, it was available for many flights at times matching the Radar Laboratory's needs, a feature important for allowing frequent re-testing and "debugging" of the continually developing complex equipment. By contrast, the Illinois group had used a C-46 belonging to the Air Force and flown by AF pilots only by pre-arrangement, resulting, in the eyes of those researchers, in limitation to a less-than-desirable frequency of flight tests of their equipment, hence a low bandwidth of feedback from tests. (Later work with newer Convair aircraft continued the Michigan group's local control of flight schedules.)
Results
Michigan's chosen -wide World War II-surplus antenna was theoretically capable of resolution, but data from only 10% of the beamwidth was used at first, the goal at that time being to demonstrate resolution. It was understood that finer resolution would require the added development of means for sensing departures of the aircraft from an ideal heading and flight path, and for using that information for making needed corrections to the antenna pointing and to the received signals before processing. After numerous trials in which even small atmospheric turbulence kept the aircraft from flying straight and level enough for good data, one pre-dawn flight in August 1957 yielded a map-like image of the Willow Run Airport area which did demonstrate resolution in some parts of the image, whereas the illuminated beam width there was . Although the program had been considered for termination by DoD due to what had seemed to be a lack of results, that first success ensured further funding to continue development leading to solutions to those recognized needs.
Public acknowledgement
The SAR principle was first acknowledged publicly via an April 1960 press release about the U. S. Army experimental AN/UPD-1 system, which consisted of an airborne element made by Texas Instruments and installed in a Beech L-23D aircraft and a mobile ground data-processing station made by WRRC and installed in a military van. At the time, the nature of the data processor was not revealed. A technical article in the journal of the IRE (Institute of Radio Engineers) Professional Group on Military Electronics in February 1961 described the SAR principle and both the C-46 and AN/UPD-1 versions, but did not tell how the data were processed, nor that the UPD-1's maximum resolution capability was about . However, the June 1960 issue of the IRE Professional Group on Information Theory had contained a long article on "Optical Data Processing and Filtering Systems" by members of the Michigan group. Although it did not refer to the use of those techniques for radar, readers of both journals could quite easily understand the existence of a connection between articles sharing some authors.
Vietnam
An operational system to be carried in a reconnaissance version of the F-4 "Phantom" aircraft was quickly devised and was used briefly in Vietnam, where it failed to favorably impress its users, due to the combination of its low resolution (similar to the UPD-1's), the speckly nature of its coherent-wave images (similar to the speckliness of laser images), and the poorly understood dissimilarity of its range/cross-range images from the angle/angle optical ones familiar to military photo interpreters. The lessons it provided were well learned by subsequent researchers, operational system designers, image-interpreter trainers, and the DoD sponsors of further development and acquisition.
Subsequent improvement
In subsequent work the technique's latent capability was eventually achieved. That work, depending on advanced radar circuit designs and precision sensing of departures from ideal straight flight, along with more sophisticated optical processors using laser light sources and specially designed very large lenses made from remarkably clear glass, allowed the Michigan group to advance system resolution, at about 5-year intervals, first to , then , and, by the mid-1970s, to 1 foot (the latter only over very short range intervals while processing was still being done optically). The latter levels and the associated very wide dynamic range proved suitable for identifying many objects of military concern as well as soil, water, vegetation, and ice features being studied by a variety of environmental researchers having security clearances allowing them access to what was then classified imagery. Similarly improved operational systems soon followed each of those finer-resolution steps.
Even the resolution stage had over-taxed the ability of cathode-ray tubes (limited to about 2000 distinguishable items across the screen diameter) to deliver fine enough details to signal films while still covering wide range swaths, and taxed the optical processing systems in similar ways. However, at about the same time, digital computers finally became capable of doing the processing without similar limitation, and the consequent presentation of the images on cathode ray tube monitors instead of film allowed for better control over tonal reproduction and for more convenient image mensuration.
Achievement of the finest resolutions at long ranges was aided by adding the capability to swing a larger airborne antenna so as to more strongly illuminate a limited target area continually while collecting data over several degrees of aspect, removing the previous limitation of resolution to the antenna width. This was referred to as the spotlight mode, which no longer produced continuous-swath images but, instead, images of isolated patches of terrain.
Out-of-the-atmosphere platform
It was understood very early in SAR development that the extremely smooth orbital path of an out-of-the-atmosphere platform made it ideally suited to SAR operation. Early experience with artificial earth satellites had also demonstrated that the Doppler frequency shifts of signals traveling through the ionosphere and atmosphere were stable enough to permit very fine resolution to be achievable even at ranges of hundreds of kilometers. The first spaceborne SAR images of Earth were demonstrated by a project now referred to as Quill (declassified in 2012).
Digitisation
After the initial work began, several of the capabilities for creating useful classified systems did not exist for another two decades.
That seemingly slow rate of advances was often paced by the progress of other inventions, such as the laser, the digital computer, circuit miniaturization, and compact data storage. Once the laser appeared, optical data processing became a fast process because it provided many parallel analog channels, but devising optical chains suited to matching signal focal lengths to ranges proceeded by many stages and turned out to call for some novel optical components. Since the process depended on diffraction of light waves, it required anti-vibration mountings, clean rooms, and highly trained operators. Even at its best, its use of CRTs and film for data storage placed limits on the range depth of images.
At several stages, attaining the frequently over-optimistic expectations for digital computation equipment proved to take far longer than anticipated. For example, the SEASAT system was ready to orbit before its digital processor became available, so a quickly assembled optical recording and processing scheme had to be used to obtain timely confirmation of system operation. In 1978, the first digital SAR processor was developed by the Canadian aerospace company MacDonald Dettwiler (MDA). When its digital processor was finally completed and used, the digital equipment of that time took many hours to create one swath of image from each run of a few seconds of data. Still, while that was a step down in speed, it was a step up in image quality. Modern methods now provide both high speed and high quality.
Data collection
Highly accurate data can be collected by aircraft overflying the terrain in question. In the 1980s, as a prototype for instruments to be flown on the NASA Space Shuttles, NASA operated a synthetic aperture radar on a NASA Convair 990. In 1986, this plane caught fire on takeoff. In 1988, NASA rebuilt a C, L, and P-band SAR to fly on the NASA DC-8 aircraft. Called AIRSAR, it flew missions at sites around the world until 2004. Another such aircraft, the Convair 580, was flown by the Canada Center for Remote Sensing until about 1996 when it was handed over to Environment Canada due to budgetary reasons. Most land-surveying applications are now carried out by satellite observation. Satellites such as ERS-1/2, JERS-1, Envisat ASAR, and RADARSAT-1 were launched explicitly to carry out this sort of observation. Their capabilities differ, particularly in their support for interferometry, but all have collected tremendous amounts of valuable data. The Space Shuttle also carried synthetic aperture radar equipment during the SIR-A and SIR-B missions during the 1980s, the Shuttle Radar Laboratory (SRL) missions in 1994 and the Shuttle Radar Topography Mission in 2000.
The Venera 15 and Venera 16 followed later by the Magellan space probe mapped the surface of Venus over several years using synthetic aperture radar.
Synthetic aperture radar was first used by NASA on JPL's Seasat oceanographic satellite in 1978 (this mission also carried an altimeter and a scatterometer); it was later developed more extensively on the Spaceborne Imaging Radar (SIR) missions on the space shuttle in 1981, 1984 and 1994. The Cassini mission to Saturn used SAR to map the surface of the planet's major moon Titan, whose surface is partly hidden from direct optical inspection by atmospheric haze. The SHARAD sounding radar on the Mars Reconnaissance Orbiter and MARSIS instrument on Mars Express have observed bedrock beneath the surface of the Mars polar ice and also indicated the likelihood of substantial water ice in the Martian middle latitudes. The Lunar Reconnaissance Orbiter, launched in 2009, carries a SAR instrument called Mini-RF, which was designed largely to look for water ice deposits on the poles of the Moon.
The Mineseeker Project is designing a system for determining whether regions contain landmines based on a blimp carrying ultra-wideband synthetic aperture radar. Initial trials show promise; the radar is able to detect even buried plastic mines.
The National Reconnaissance Office maintains a fleet of (now declassified) synthetic aperture radar satellites commonly designated as Lacrosse or Onyx.
In February 2009, the Sentinel R1 surveillance aircraft entered service in the RAF, equipped with the SAR-based Airborne Stand-Off Radar (ASTOR) system.
The German Armed Forces' (Bundeswehr) military SAR-Lupe reconnaissance satellite system has been fully operational since 22 July 2008.
As of January 2021, multiple commercial companies have started launching constellations of satellites for collecting SAR imagery of Earth.
Data distribution
The Alaska Satellite Facility provides production, archiving and distribution to the scientific community of SAR data products and tools from active and past missions, including the June 2013 release of newly processed, 35-year-old Seasat SAR imagery.
The Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) downlinks and processes SAR data (as well as other data) from a variety of satellites and supports the University of Miami's Rosenstiel School of Marine, Atmospheric, and Earth Science. CSTARS also supports disaster relief operations, oceanographic and meteorological research, and port and maritime security research projects.
See also
History of radar
References
20th century in technology
History of astronomy
Synthetic-aperture radar
Military technology
Planetary science
Synthetic aperture radar | History of synthetic-aperture radar | [
"Astronomy",
"Technology"
] | 3,947 | [
"History of astronomy",
"History of science",
"Planetary science",
"History of science and technology",
"Astronomical sub-disciplines"
] |
71,515,469 | https://en.wikipedia.org/wiki/Leucocoprinus%20magnusianus | Leucocoprinus magnusianus is a species of mushroom producing fungus in the family Agaricaceae.
Taxonomy
It was first described in 1891 by the German mycologist Paul Christoph Hennings who classified it as Lepiota magnusiana.
The German mycologist Rolf Singer reclassified it as Hiatula magnusiana in 1943 and then as Leucocoprinus magnusianus in 1949.
Description
Lepiota magnusiana only has a brief description provided by Hennings. It is described as having red flesh and a stem which discolours reddish. This is a common feature in Lepiota species but would be unusual for a Leucocoprinus.
Cap: 1–5 cm wide, starting ovoid or cylindrical before expanding to campanulate (bell shaped) with thin flesh. The surface is white and covered in powdery scales whilst the centre discolours yellow with age and the cap edges are striated. Gills: Free, crowded and white. Stem: 2–7 cm tall and 2–3 mm thick with a white surface that discolours reddish and a hollow interior. The membranous stem ring has a woolly (floccose) texture. Spores: Ovoid. Smell: Indistinct.Taste: Indistinct.
Habitat and distribution
L. magnusianus is scarcely recorded and little known. Hennings documented it from a hothouse in the Berlin botanical garden.
References
Leucocoprinus
Taxa named by Rolf Singer
Fungi described in 1891
Fungus species | Leucocoprinus magnusianus | [
"Biology"
] | 316 | [
"Fungi",
"Fungus species"
] |
71,515,699 | https://en.wikipedia.org/wiki/Boscalid | Boscalid is a broad spectrum fungicide used in agriculture to protect crops from fungal diseases. It was first marketed by BASF in 2002 using their brand name Endura. The compound is an biphenyl amide derived inhibitor of succinate dehydrogenase.
History
Inhibition of succinate dehydrogenase, the complex II in the mitochondrial respiration chain, has been known as a fungicidal mechanism of action since the first examples were marketed in the 1960s. The first compound in this class was carboxin, which had a narrow spectrum of useful biological activity, mainly on basidiomycetes and was used as a seed treatment. Many companies made analogues with the aim of expanding the range of species controlled and boscalid was successful in doing so.
Synthesis
The first synthesis of boscalid was disclosed in patents filed by BASF in 1995.
The aminobiphenyl required for reaction with the acid chloride of 2-chloronicotinic acid is prepared in two steps. The first is a palladium-catalysed Suzuki reaction, followed by reduction. As the final product has been manufactured at the multi-tonne scale, considerable efforts have been made to optimise these reactions.
Mechanism of action
Succinate dehydrogenase inhibitors (SDHI) of this type act by binding at the quinone reduction site of the enzyme complex, preventing ubiquinone from doing so. As a consequence, the tricarboxylic acid cycle and electron transport chain cannot function.
Usage
Boscalid has fungicidal effects against a wide range of crop pests. These include Alternaria, grey mold (Botrytis cinerea), white mold (Sclerotinia sclerotiorum), and powdery mildew (Uncinula necator). As a result, it has use in crops including fruits, soybeans and vegetables.
The estimated annual use of boscalid in US agriculture is mapped by the US Geological Survey and shows that it is mainly applied to fruit crops, with a maximum use of over in 2016. Global sales in 2014 were estimated at $390 million. The compound lacks full control of important cereal diseases, especially septoria leaf blotch Zymoseptoria tritici, which has limited its potential.
Human safety
Boscalid has low acute toxicity: the Codex Alimentarius database maintained by the FAO lists the maximum residue limits for it in various food products.
Environmental effects
The compound is very persistent in field conditions and its environmental fate and consequent ecotoxicology have been reviewed.
Resistance management
Fungal populations have the ability to develop resistance to SDHI inhibitors. This potential can be mitigated by careful management. Reports of individual pest species becoming resistant are monitored by manufacturers, regulatory bodies such as the EPA and the Fungicides Resistance Action Committee (FRAC). The risks of resistance developing can be reduced by using a mixture of two or more fungicides which each have activity on relevant pests but with unrelated mechanisms of action. FRAC assigns fungicides into classes so as to facilitate this.
Brands
Boscalid is the ISO common name for the active ingredient which is formulated into the branded product sold to end-users. It was also known as nicobifen. Endura and Emerald are the brand names first used by BASF's formulations but the compound has subsequently been sold under a range of product names.
References
External links
PPDB pesticides properties database entry for boscalid
Fungicides
Pyridines
4-Chlorophenyl compounds
Carboxamides
Anilides
Biphenyls | Boscalid | [
"Biology"
] | 748 | [
"Fungicides",
"Biocides"
] |
71,515,739 | https://en.wikipedia.org/wiki/Friedrich%20Wilhelm%20Heinrich%20von%20Trebra | Friedrich Wilhelm Heinrich von Trebra (5 April 1740 – 16 July 1819) was a mining officer in Saxony. He took an interest in geology and was a friend of Johann Wolfgang von Goethe who worked in Ilmenau. He was involved in the recovery of Saxon mining following the Seven Years' War.
Trebra came from a noble family of Thuringia and was born in Allstedt, son of Christoph Heinrich von Trebra (1694-1745) and Amalia Carolina Liberta née von Werder. He studied at Roßleben and law at the University of Jena before joining the newly created mining school in Freiberg after meeting Friedrich Anton von Heynitz in 1766. He then became a superintendent (Bergmeister) of the mines in Marienberg in 1767 and rose to mining captain in 1773. He was in charge of mines in Saxony for which he got Dutch investors and introduced a number of innovations including improved conditions of the miners. He became a friend of Goethe who was in charge of the mines at Ilmenau. He moved to Clausthal in 1779 to replace Claus Friedrich von Reden. Trebra founded a society for mining science, the Societät der Bergbaukunde in 1786. He attempted to bring in new subjects at the Bergakademie but conflicted with Abraham Gottlob Werner. He resigned in 1795 and moved to his estate in Bretleben where he worked on agriculture. He took a position as inspector of mines for Saxony in 1801 and remained there until his death.
References
External links
Erfahrungen vom Innern der Gebirge (1785)
Mineraliencabinett (1795)
Dutch investors for Saxon mines
1740 births
1819 deaths
Mining engineers
University of Jena alumni
18th-century German engineers | Friedrich Wilhelm Heinrich von Trebra | [
"Engineering"
] | 354 | [
"Mining engineering",
"Mining engineers"
] |
71,516,052 | https://en.wikipedia.org/wiki/Octafluorocubane | Octafluorocubane or perfluorocubane is an organofluorine compound with the formula , consisting of eight carbon atoms joined into a cube, with a fluorine bonded to each carbon corner. It is a colorless, sublimable solid at room temperature. It has been of longstanding theoretical interest, but was not synthesised until 2022, when it was prepared in several steps from a cubane carboxylic ester beginning with its heptafluorination. According to X-ray crystallography, the C-C distances (1.570 Å) in octafluorocubane are identical in length to those in the parent cubane (1.572 Å).
Octafluorocubane has attracted interest from theorists because of its unusual electronic structure, which is indicated by its susceptibility to undergo reduction to a detectable anion , with the free electron trapped inside of the cube.
The compound was voted "favorite molecule of 2022" by readers of Chemical & Engineering News.
References
Fluorocarbons
Molecular geometry
Theoretical chemistry
Cyclobutanes
Pentacyclic compounds | Octafluorocubane | [
"Physics",
"Chemistry"
] | 239 | [
"Molecular geometry",
"Molecules",
"Stereochemistry",
"Theoretical chemistry",
"Stereochemistry stubs",
"nan",
"Matter"
] |
49,128,024 | https://en.wikipedia.org/wiki/NGC%201448 | NGC 1448 is an unbarred spiral galaxy seen nearly edge-on in the constellation Horologium. It is at a distance of 55 million light years from Earth. It was discovered by British astronomer John Herschel on 24 October 1835. Herschel observed the galaxy again on 14 December 1835, resulting in it being listed twice in the New General Catalogue, as NGC 1448 and as NGC 1457.
From the spectral analysis of SN 2001el, over a dozen diffuse interstellar bands were discovered in NGC 1448 – one of the few cases that these bands were observed outside of the Milky Way. However, the bands were significantly weaker at SN 2003hn.
In January 2017 it was announced that evidence for a supermassive black hole in NGC 1448 had been found in the center of the galaxy.
The galaxy belongs to the NGC 1433 group, part of the Doradus cloud of galaxies.
Supernovae
Six supernovae have been observed in NGC 1448:
SN 1983S (type II, mag. 14.5) was discovered by Robert Evans on 6 October 1983.
SN 2001el (type Ia, mag. 14.5) was discovered by Berto Monard (bio-fr) on 17 September 2001. It reached magnitude 12.3, making it the brightest supernova of 2001.
SN 2003hn (type II, mag. 14.1) was discovered by Robert Evans on 25 August 2003.
SN 2014df (type Ib, mag. 14) was discovered by Berto Monard on 3 June 2014.
SN 2020zbv (type IIP, mag. 18.83) was discovered by the Distance Less Than 40 Mpc Survey (DLT40) on 10 November 2020.
SN 2021pit (type Ia, mag. 13.5) was discovered by ASAS-SN on 10 June 2021.
Gallery
See also
List of NGC objects (1001–2000)
References
External links
Horologium (constellation)
Unbarred spiral galaxies
1448
013727
Dorado Group
03428-4448
-07-08-005
18351024
Discoveries by John Herschel | NGC 1448 | [
"Astronomy"
] | 442 | [
"Constellations",
"Horologium (constellation)"
] |
49,129,093 | https://en.wikipedia.org/wiki/Homeobox%20protein%20CDX-4 | Homeobox protein CDX-4 is a protein that in humans is encoded by the CDX4 gene. This gene is a member of the caudal-related homeobox transcription factor family that also includes CDX1 and CDX2.
Function
The transcription factor encoded by the CDX4 gene participates in the formation of extra-embryonic tissues, anterior-posterior patterning and blood formation during embryogenesis. It does so through the regulation of Hox gene expression.
Before placentation takes place, CDX4 plays a role in its development. CDX4 mutants are born healthy and are fertile, however its importance is revealed in compound CDX mutants. Compound mutants carrying one CDX2 null allele and homozygous null for CDX4 fail to generate posterior tissue caudal to the hindlimbs and most of these embryos die around embryonic day 10.5 from lack of placental development. Around 10% of this phenotype may progress to full term, but then die shortly after birth. Upon inspection the morphogenesis of ano-rectal and urethral tissues was observed.
The most well described function of CDX genes are their role in caudal body formation. Transcription factors of the CDX gene family, in part control Hox gene expression by responding to signaling molecules Retinoic Acid, Wnt, and FGF. The redundant contribution of CDX4 in axial elongation is shown in that neither CDX4 null or CDX1/CDX4 compound mutants appear with impaired axial elongation. However, CDX4 does have a role in determining pancreatic B-cell number, specifying anterior-posterior location of the foregut organs including the pancreas and liver. Thus, an abnormal state is shown in embryos deficient in CDX4 by posteriorly shifted pancreas, liver and small intestines.
In blood formation, CDX4 regulation of Hox genes is necessary for the specification of hematopoietic cell fate during embryogenesis. This is demonstrated by the fact that blood deficiencies in CDX4 mutants can be rescued by the over expression of certain Hox genes.
Knockout models have been generated in mice as described in CDX4’s role in caudal body formation.
References
External links
Transcription factors | Homeobox protein CDX-4 | [
"Chemistry",
"Biology"
] | 479 | [
"Induced stem cells",
"Gene expression",
"Transcription factors",
"Signal transduction"
] |
49,131,748 | https://en.wikipedia.org/wiki/ADAM20 | Disintegrin and metalloproteinase domain-containing protein 20 is an enzyme that in humans is encoded by the ADAM20 gene. It is a membrane disintegrin-metalloprotease that belongs to the ADAM family. It is exclusively expressed in Testes and is similar to sperm cell-specific fertilins -alpha and -beta.
Its cDNA is tightly linked to marker SHGC-36001 on chromosome 14q24.1. ADAM20 is related to fertilin α (ADAM1A/B pseudogene), fertilin β (ADAM2), and fertilin γ (ADAM9). In humans, fertilin α has recently been deactivated so ADAM20 may be the functional equivalent fertilin α in humans.
Structure
In common with other ADAM family members, ADAM20 contains a N-terminal reprolysin family propeptide (residues 57–159), reprolysin (M12B) family zinc metalloprotease domain (207–395), disintegrin domain (416–488), and a C-terminal ADAM cysteine-rich domain (493–605).
The propeptide acts both a signal peptide and an activator domain. This prodomain has a cysteine that interacts with a zinc in the catalytic domain, thereby preventing the catalytic activity of the protein.When the pro-protein domain is cleaved, this cysteine zinc bond is broken and the protein is activated. A notable variant showed an amino acid difference in the pro protein domain that prevented the cleavage of this domain which prevented the fusion of the sperm cell to an egg.
References
Proteases
Protein families | ADAM20 | [
"Chemistry",
"Biology"
] | 359 | [
"Biochemistry stubs",
"Protein families",
"Protein stubs",
"Protein classification"
] |
49,132,760 | https://en.wikipedia.org/wiki/Sparks%E2%80%93Thomas%20Award | The purpose of the Sparks–Thomas Award, given by the ACS Rubber Division, is to recognize and encourage outstanding contributions and innovations in the field of elastomers by younger scientists, technologists, and engineers. The award is named for Exxon scientists William J. Sparks and Robert M. Thomas, co-inventors of Butyl rubber.
Recipients
The following persons have received the award:
See also
List of chemistry awards
International Rubber Science Hall of Fame: Another ACS award
Melvin Mooney Distinguished Technology Award
Charles Goodyear Medal
References
External links
Chemistry awards
Awards of the American Chemical Society | Sparks–Thomas Award | [
"Technology"
] | 120 | [
"Science and technology awards",
"Chemistry awards"
] |
49,133,571 | https://en.wikipedia.org/wiki/N-Phenacylthiazolium%20bromide | N-Phenacylthiazolium bromide (PTB) is a cross-link breaker that in one study has been shown to prevent vascular advanced glycation end-product accumulation in diabetic rats.
References
Bromides
Thiazoles | N-Phenacylthiazolium bromide | [
"Chemistry"
] | 55 | [
"Salts",
"Organic compounds",
"Bromides",
"Organic compound stubs",
"Organic chemistry stubs"
] |
49,134,386 | https://en.wikipedia.org/wiki/Something%20Ricked%20This%20Way%20Comes | "Something Ricked This Way Comes" is the ninth episode of the first season of the American science fiction comedy television series Rick and Morty. Aired on March 24, 2014, the episode was directed by John Rice and written by Mike McMahan. The episode aired on March 6, 2016 in Canada. It stars Justin Roiland as Rick Sanchez and Morty Smith.
The title is a reference to the dark fantasy novel Something Wicked This Way Comes by Ray Bradbury, in which "Mr. Dark", the sinister leader of a traveling carnival comes to town, granting the townsfolk's secret desires but always paired with an ironic twist. For example, a 50-year-old schoolteacher wishes to be young again and is transformed into a little girl but is now blind. A stand-alone sequel miniseries, Rick and Morty Go to Hell, was published by Oni Press from April 29 to October 21, 2020.
Plot
In a take on Needful Things, Summer works in an antique shop run by the Devil (under the alias of Lucius Needful), which gives away items that come with harmful curses. After Rick is given a microscope that would have greatly diminished his intelligence, he develops technology that can quantify evil and detect curses. Rick then sets up a competing shop where he uses science to remove the curses, and the Devil is put out of business. Summer helps him to successfully re-launch the shop online as N33dful, but he betrays her and keeps the company for himself. Rick has become bored with running a business and burns the shop down, then he and Summer build muscle and publicly beat up the Devil to get revenge.
Meanwhile, Jerry, helping Morty with a model Solar System as a science fair project, insists that Pluto is a planet, going so far as to lobby NASA to re-instate its planetary status. They are abducted by Plutonians to their planet, where Jerry is mistaken for a scientist. His statements about Pluto being a planet make him instantly popular. Morty is told by Scroopy Noopers, a leading Plutonian scientist, that Pluto is shrinking due to corporate plutonium mining which will ultimately lead to its destruction, and that the Plutonian leadership is keeping the population distracted by assuring them Pluto is still a planet. Morty fails to convince Jerry of Pluto's diminishing size and the resultant cover-up, returning to Earth in frustration. However, after witnessing the arrest of Scroopy Noopers and hearing Flippy Nips, the King of Pluto and Scroopy Noopers's father, lets slip that Pluto is in fact a celestial dwarf, Jerry tells the Plutonian citizens the truth and denounces himself in a public speech, causing him to be hated and deported back to Earth. Jerry apologises to Morty and asks if they could finish his science fair project, but Morty tells him that he instead plans to hand in a robot built by Rick to pass butter.
In a post-credits scene, Summer and Rick use their new muscle mass to beat up a neo-Nazi, a bully, a member of the Westboro Baptist Church and an abusive dog owner, as "X Gon' Give It to Ya" by DMX plays in the background.
Reception
Corey Plante of Inverse praised the unusual Morty-Jerry storyline in the episode, but criticized other parts of it, saying "So the surface level plots of "Something Ricked This Way Comes" feel pretty boring, with one being more derivative than it is subversive and the other being a long-winded joke." Zack Handlen of The A.V. Club said: "It's a riff on climate change deniers: when the truth is that unsettling, people would much rather pretend they can make it go away by listening to an idiot."
References
Pluto's planethood
2014 American television episodes
Parodies of works by Stephen King | Something Ricked This Way Comes | [
"Astronomy"
] | 805 | [
"Astronomical controversies",
"Pluto's planethood"
] |
49,134,790 | https://en.wikipedia.org/wiki/Frenkel%E2%80%93Kontorova%20model | The Frenkel–Kontorova (FK) model is a fundamental model of low-dimensional nonlinear physics.
The generalized FK model describes a chain of classical particles with nearest neighbor interactions and subjected to a periodic on-site substrate potential. In its original and simplest form the interactions are taken to be harmonic and the potential to be sinusoidal with a periodicity commensurate with the equilibrium distance of the particles. Different choices for the interaction and substrate potentials and inclusion of a driving force may describe a wide range of different physical situations.
Originally introduced by Yakov Frenkel and in 1938 to describe the structure and dynamics of a crystal lattice near a dislocation core, the FK model has become one of the standard models in condensed matter physics due to its applicability to describe many physical phenomena. Physical phenomena that can be modeled by FK model include dislocations, the dynamics of adsorbate layers on surfaces, crowdions, domain walls in magnetically ordered structures, long Josephson junctions, hydrogen-bonded chains, and DNA type chains. A modification of the FK model, the Tomlinson model, plays an important role in the field of tribology.
The equations for stationary configurations of the FK model reduce to those of the standard map or Chirikov–Taylor map of stochastic theory.
In the continuum-limit approximation the FK model reduces to the exactly integrable sine-Gordon (SG) equation, which allows for soliton solutions. For this reason the FK model is also known as the "discrete sine-Gordon" or "periodic Klein–Gordon equation".
History
A simple model of a harmonic chain in a periodic substrate potential was proposed by Ulrich Dehlinger in 1928. Dehlinger derived an approximate analytical expression for the stable solutions of this model, which he termed , which correspond to what is today called kink pairs. An essentially similar model was developed by Ludwig Prandtl in 1912/13 but did not see publication until 1928.
The model was independently proposed by Yakov Frenkel and Tatiana Kontorova in their 1938 article On the theory of plastic deformation and twinning to describe the dynamics of a crystal lattice near a dislocation and to describe crystal twinning. In the standard linear harmonic chain any displacement of the atoms will result in waves, and the only stable configuration will be the trivial one.
For the nonlinear chain of Frenkel and Kontorova, there exist stable configurations beside the trivial one. For small atomic displacements the situation resembles the linear chain; however, for large enough displacements, it is possible to create a moving single dislocation, for which an analytical solution was derived by Frenkel and Kontorova. The shape of these dislocations is defined only by the parameters of the system such as the mass and the elastic constant of the springs.
Dislocations, also called solitons, are distributed non-local defects and mathematically are a type of topological defect. The defining characteristic of solitons/dislocations is that they behave much like stable particles, they can move while maintaining their overall shape. Two solitons of equal and opposite orientation may cancel upon collision, but a single soliton can not annihilate spontaneously.
Generalized model
The generalized FK model treats a one-dimensional chain of atoms with nearest-neighbor interaction in periodic on-site potential, the Hamiltonian for this system is
where the first term is the kinetic energy of the atoms of mass , and the potential energy is a sum of the potential energy due to the nearest-neighbor interaction and that of the substrate potential: .
The substrate potential is periodic, i.e. for some .
For non-harmonic interactions and/or non-sinusoidal potential, the FK model will give rise to a commensurate–incommensurate phase transition.
The FK model can be applied to any system that can be treated as two coupled sub-systems where one subsystem can be approximated as a linear chain and the second subsystem as a motionless substrate potential.
An example would be the adsorption of a layer onto a crystal surface, here the adsorption layer can be approximated as the chain, and the crystal surface as an on-site potential.
Classical model
In this section we examine in detail the simplest form of the FK model. A detailed version of this derivation can be found in the literature. The model describes a one-dimensional chain of atoms with a harmonic nearest neighbor interaction and subject to a sinusoidal potential. Transverse motion of the atoms is ignored, i.e. the atoms can only move along the chain.
The Hamiltonian for this situation is given by , where we specify the interaction potential to be
where is the elastic constant, and is the inter-atomic equilibrium distance. The substrate potential is
with being the amplitude, and the period.
The following dimensionless variables are introduced in order to rewrite the Hamiltonian:
In dimensionless form the Hamiltonian is
which describes a harmonic chain of atoms of unit mass in a sinusoidal potential of period with amplitude . The equation of motion for this Hamiltonian is
We consider only the case where and are commensurate, for simplicity we take . Thus in the ground state of the chain each minimum of the substrate potential is occupied by one atom.
We introduce the variable for atomic displacements which is defined by
For small displacements the equation of motion may be linearized and takes the following form:
This equation of motion describes phonons with with the phonon dispersion relation with the dimensionless wavenumber . This shows that the frequency spectrum of the chain has a band gap with cut-off frequency .
The linearised equation of motion are not valid when the atomic displacements are not small, and one must use the nonlinear equation of motion.
The nonlinear equations can support new types of localized excitations, which are best illuminated by considering the continuum limit of the FK model. Applying the standard procedure of Rosenau to derive continuum-limit equations from a discrete lattice results in the perturbed sine-Gordon equation
where the function
describes in first order the effects due to the discreteness of the chain.
Neglecting the discreteness effects and introducing reduces the equation of motion to the sine-Gordon (SG) equation in its standard form
The SG equation gives rise to three elementary excitations/solutions: kinks, breathers and phonons.
Kinks, or topological solitons, can be understood as the solution connecting two nearest identical minima of the periodic substrate potential, thus they are a result of the degeneracy of the ground state. These solutions are
where is the topological charge. For the solution is called a kink, and for it is an antikink. The kink width is determined by the kink velocity , where is measured in units of the sound velocity and is . For kink motion with , the width approximates 1.
The energy of the kink in dimensionless units is
from which the rest mass of the kink follows as , and the kinks rest energy as .
Two neighboring static kinks with distance have energy of repulsion
whereas kink and antikink attract with interaction
A breather is
which describes nonlinear oscillation with frequency , with .
The breather rest energy
For low frequencies the breather can be seen as a coupled kink–antikink pair. Kinks and breathers can move along the chain without any dissipative energy loss. Furthermore, any collision between all the excitations of the SG equation result in only a phase shift. Thus kinks and breathers may be considered nonlinear quasi-particles of the SG model. For nearly integrable modifications of the SG equation such as the continuum approximation of the FK model kinks can be considered deformable quasi-particles, provided that discreetness effects are small.
The Peierls–Nabarro potential
In the preceding section the excitations of the FK model were derived by considering the model in a continuum-limit approximation. Since the properties of kinks are only modified slightly by the discreteness of the primary model, the SG equation can adequately describe most features and dynamics of the system.
The discrete lattice does, however, influence the kink motion in a unique way with the existence of the Peierls–Nabarro (PN) potential , where is the position of the kink's center. The existence of the PN potential is due to the lack of translational invariance in a discrete chain. In the continuum limit the system is invariant for any translation of the kink along the chain. For a discrete chain, only those translations that are an integer multiple of the lattice spacing leave the system invariant. The PN barrier, , is the smallest energy barrier for a kink to overcome so that it can move through the lattice. The value of the PN barrier is the difference between the kink's potential energy for a stable and unstable stationary configuration. The stationary configurations are shown schematically in the figure.
References
Classical mechanics
Lattice models
Solitons | Frenkel–Kontorova model | [
"Physics",
"Materials_science"
] | 1,867 | [
"Classical mechanics",
"Lattice models",
"Computational physics",
"Mechanics",
"Condensed matter physics",
"Statistical mechanics"
] |
49,134,970 | https://en.wikipedia.org/wiki/European%20Years | Every year, the European Union chooses to address a subject in order to encourage debate and dialogue within and between member states raising the awareness of European citizens to a specific problem.
History
Beginning in 1983, the European Parliament and the Council of the European Union have chosen an annual theme of action each year, based on a European Commission proposal. European Years are an awareness campaign to educate European citizens and attract the attention of national governments of Member States to a particular issue, in order to change attitudes and behaviours at both the national and European level.
Years
References
External links
European years (europa.eu)
Calendars
International observances
Cultural lists
European Union | European Years | [
"Physics"
] | 130 | [
"Spacetime",
"Calendars",
"Physical quantities",
"Time"
] |
49,136,553 | https://en.wikipedia.org/wiki/Vector%20generalized%20linear%20model | In statistics, the class of vector generalized linear models (VGLMs) was proposed to
enlarge the scope of models catered for by generalized linear models (GLMs).
In particular, VGLMs allow for response variables outside the classical exponential family
and for more than one parameter. Each parameter (not necessarily a mean) can be transformed by a link function.
The VGLM framework is also large enough to naturally accommodate multiple responses; these are
several independent responses each coming from a particular statistical distribution with
possibly different parameter values.
Vector generalized linear models are described in detail in Yee (2015).
The central algorithm adopted is the iteratively reweighted least squares method,
for maximum likelihood estimation of usually all the model parameters. In particular,
Fisher scoring is implemented by such, which, for most models,
uses the first and expected second derivatives of the log-likelihood function.
Motivation
GLMs essentially cover one-parameter models from the classical exponential family,
and include 3 of the most important statistical regression models:
the linear model, Poisson regression for counts, and logistic regression
for binary responses.
However, the exponential family is far too limiting for regular data analysis.
For example, for counts, zero-inflation, zero-truncation and overdispersion are regularly
encountered, and the makeshift adaptations made to the binomial and
Poisson models in the form of quasi-binomial and
quasi-Poisson can be argued as being ad hoc and unsatisfactory.
But the VGLM framework readily handles models such as
zero-inflated Poisson regression,
zero-altered Poisson (hurdle) regression,
positive-Poisson regression, and
negative binomial regression.
As another example, for the linear model,
the variance of a normal distribution is relegated
as a scale parameter and it is treated
often as a nuisance parameter (if it is considered as a parameter at all).
But the VGLM framework allows the variance to be modelled using covariates.
As a whole, one can loosely think of VGLMs as GLMs that handle many models
outside the classical exponential family and are not restricted to estimating
a single mean.
During estimation,
rather than using weighted least squares
during IRLS, one uses generalized least squares to handle the
correlation between the M linear predictors.
Data and notation
We suppose that the response or outcome or the dependent variable(s), , are assumed to be generated from a particular distribution. Most distributions are univariate, so that , and an example of is the bivariate normal distribution.
Sometimes we write our data as
for . Each of the n observations are considered to be
independent.
Then .
The are known positive prior weights, and often .
The explanatory or independent variables are written ,
or when i is needed, as .
Usually there is an intercept, in which case
or .
Actually, the VGLM framework allows for S responses, each of dimension .
In the above S = 1. Hence the dimension of is more generally . One handles S responses by code such
as vglm(cbind(y1, y2, y3) ~ x2 + x3, ..., data = mydata) for S = 3.
To simplify things, most of this article has S = 1.
Model components
The VGLM usually consists of four elements:
1. A probability density function or probability mass function from some statistical distribution which has a log-likelihood , first derivatives and expected information matrix that can be computed. The model is required to satisfy the usual MLE regularity conditions.
2. Linear predictors described below to model each parameter ,
3. Link functions such that
4. Constraint matrices for each of full column-rank and known.
Linear predictors
Each linear predictor is a quantity which incorporates
information about the independent variables into the model.
The symbol (Greek "eta")
denotes a linear predictor and a subscript j is used to denote the jth one.
It relates the jth parameter to the explanatory variables, and
is expressed as linear combinations (thus, "linear")
of unknown parameters
i.e., of regression coefficients .
The jth parameter, , of the distribution depends on the
independent variables, through
Let be the vector of
all the linear predictors. (For convenience we always let
be of dimension M).
Thus all the covariates comprising potentially affect all the parameters through the linear predictors . Later, we will allow the linear predictors to be generalized to additive predictors, which is the sum of smooth functions of each and each function is estimated from the data.
Link functions
Each link function provides the relationship between a linear predictor and a
parameter of the distribution.
There are many commonly used link functions, and their choice can be somewhat arbitrary. It makes sense to try to match the domain of the link function to
the range of the distribution's parameter value.
Notice above that the allows a different link function for each parameter.
They have similar properties as with generalized linear models, for example,
common link functions include the logit link for parameters in ,
and the log link for positive parameters. The VGAM package has function identitylink() for parameters that can assume both positive and negative values.
Constraint matrices
More generally, the VGLM framework allows for any linear constraints between the regression coefficients of each linear predictors. For example, we may want to set some to be equal to 0, or constraint some of them to be equal. We have
where the are the constraint matrices.
Each constraint matrix is known and prespecified, and has M rows, and between 1 and M columns. The elements of constraint matrices are finite-valued, and often they are just 0 or 1.
For example, the value 0 effectively omits that element while a 1 includes it.
It is common for some models to have a parallelism assumption, which means that
for , and
for some models, for too.
The special case when for
all is known as trivial constraints; all the
regression coefficients are estimated and are unrelated.
And is known as an intercept-only parameter
if the jth row of all the are equal to for , i.e., equals an intercept only. Intercept-only parameters are thus modelled as simply as possible, as a scalar.
The unknown parameters, ,
are typically estimated by the method of maximum likelihood.
All the regression coefficients may be put into a matrix as follows:
The xij facility
With even more generally, one can allow the value of a variable
to have a different value for each .
For example, if each linear predictor is for a different time point then
one might have a time-varying covariate.
For example,
in discrete choice models, one has
conditional logit models,
nested logit models,
generalized logit models,
and the like, to distinguish between certain variants and
fit a multinomial logit model to, e.g., transport choices.
A variable such as cost differs depending on the choice, for example,
taxi is more expensive than bus, which is more expensive than walking.
The xij facility of VGAM allows one to
generalize
to .
The most general formula is
Here the is an optional offset; which translates
to be a matrix in practice.
The VGAM package has an xij argument that allows
the successive elements of the diagonal matrix to be inputted.
Software
Yee (2015) describes an R package
implementation in the
called VGAM.
Currently this software fits approximately 150 models/distributions.
The central modelling functions are vglm() and vgam().
The family argument is assigned a VGAM family function,
e.g., family = negbinomial for negative binomial regression,
family = poissonff for Poisson regression,
family = propodds for the proportional odd model or
cumulative logit model for ordinal categorical regression.
Fitting
Maximum likelihood
We are maximizing a log-likelihood
where the are positive and known prior weights.
The maximum likelihood estimates can be found
using an iteratively reweighted least squares algorithm using
Fisher's scoring method, with updates of the form:
where is
the Fisher information matrix at iteration a.
It is also called the expected information matrix, or EIM.
VLM
For the computation, the (small) model matrix constructed
from the RHS of the formula in vglm()
and the constraint matrices are combined to form a big model matrix.
The IRLS is applied to this big X. This matrix is known as the VLM
matrix, since the vector linear model is the underlying least squares
problem being solved. A VLM is a weighted multivariate regression where the
variance-covariance matrix for each row of the response matrix is not
necessarily the same, and is known.
(In classical multivariate regression, all the errors have the
same variance-covariance matrix, and it is unknown).
In particular, the VLM minimizes the weighted sum of squares
This quantity is minimized at each IRLS iteration.
The working responses (also known as pseudo-response and adjusted dependent vectors) are
where the are known as working weights or working weight matrices. They are symmetric and positive-definite. Using the EIM helps ensure that they are all positive-definite (and not just the sum of them) over much of the parameter space. In contrast, using Newton–Raphson would mean the observed information matrices would be used, and these tend to be positive-definite in a smaller subset of the parameter space.
Computationally, the Cholesky decomposition is used to invert the working weight matrices and to convert the overall generalized least squares problem into an ordinary least squares problem.
Examples
Generalized linear models
Of course, all generalized linear models are a special cases of VGLMs.
But we often estimate all parameters by full maximum likelihood estimation rather
than using the method of moments for the scale parameter.
Ordered categorical response
If the response variable is an ordinal measurement with M + 1 levels, then one may fit a model function of the form:
where
for
Different links g lead to proportional odds models or ordered probit models,
e.g., the VGAM family function cumulative(link = probit) assigns a probit link to the cumulative
probabilities, therefore this model is also called the cumulative probit model.
In general they are called cumulative link models.
For categorical and multinomial distributions, the fitted values are an (M + 1)-vector of probabilities, with the property that all probabilities add up to 1. Each probability indicates the likelihood of occurrence of one of the M + 1 possible values.
Unordered categorical response
If the response variable is a nominal measurement,
or the data do not satisfy the assumptions of an ordered model, then one may fit a model of the following form:
for The above link is sometimes called the multilogit link,
and the model is called the multinomial logit model.
It is common to choose the first or the last level of the response as the
reference or baseline group; the above uses the last level.
The VGAM family function multinomial() fits the above model,
and it has an argument called refLevel that can be assigned
the level used for as the reference group.
Count data
Classical GLM theory performs Poisson regression for count data.
The link is typically the logarithm, which is known as the canonical link.
The variance function is proportional to the mean:
where the dispersion parameter is typically fixed at exactly one. When it is not, the resulting quasi-likelihood model is often described as Poisson with overdispersion, or quasi-Poisson; then is commonly estimated by the method-of-moments and as such,
confidence intervals for are difficult to obtain.
In contrast, VGLMs offer a much richer set of models to handle overdispersion with respect to the Poisson, e.g., the negative binomial distribution and several variants thereof. Another count regression model is the generalized Poisson distribution. Other possible models are the zeta distribution and the Zipf distribution.
Extensions
Reduced-rank vector generalized linear models
RR-VGLMs are VGLMs where a subset of
the B matrix is of a lower rank.
Without loss of generality, suppose that is a partition of the covariate vector. Then the part of the B matrix corresponding to is of the form where and
are thin matrices (i.e., with R columns), e.g., vectors if the rank R = 1. RR-VGLMs potentially offer several advantages when applied to certain
models and data sets. Firstly, if M and p are large then the number of regression coefficients
that are estimated by VGLMs is large (). Then RR-VGLMs can reduce the number of estimated regression coefficients enormously if R is low, e.g., R = 1
or R = 2. An example of a model where this is particularly useful is the RR-multinomial logit model, also known as the stereotype model.
Secondly,
is an R-vector of latent variables, and often these can be usefully interpreted.
If R = 1 then we can write
so that the latent variable comprises loadings on the explanatory variables.
It may be seen that RR-VGLMs take optimal linear combinations of the
and then a VGLM is fitted to the explanatory variables . Thirdly, a biplot can be produced if R = 2 , and this allows the model to be visualized.
It can be shown that RR-VGLMs are simply VGLMs where the constraint matrices for
the variables in are unknown and to be estimated.
It then transpires that for
such variables.
RR-VGLMs can be estimated by an alternating algorithm which fixes
and estimates and then fixes and estimates , etc.
In practice, some uniqueness constraints are needed for
and/or . In VGAM, the rrvglm() function uses corner constraints by default, which means that the top R rows of is set to . RR-VGLMs were proposed in 2003.
Two to one
A special case of RR-VGLMs is when R = 1 and M = 2. This is dimension reduction from 2 parameters to 1 parameter. Then it can be shown that
where elements and are estimated. Equivalently,
This formula provides a coupling of and . It induces a relationship between two parameters of a model that can be useful, e.g., for modelling a mean-variance relationship. Sometimes there is some choice of link functions, therefore it offers a little flexibility when coupling the two parameters, e.g., a logit, probit, cauchit or cloglog link for parameters in the unit interval. The above formula is particularly useful for the negative binomial distribution, so that the RR-NB has variance function
This has been called the NB-P variant by some authors. The and are estimated, and it is also possible to obtain approximate confidence intervals for them too.
Incidentally, several other useful NB variants can also be fitted, with the help of selecting the right combination of constraint matrices. For example, NB − 1, NB − 2 (negbinomial() default), NB − H; see Yee (2014) and Table 11.3 of Yee (2015).
RCIMs
The subclass of row-column interaction models
(RCIMs) has also been proposed; these are a special type of RR-VGLM.
RCIMs apply only to a matrix Y response and there are
no explicit explanatory variables .
Instead, indicator variables for each row and column are explicitly set up, and an order-R
interaction of the form is allowed.
Special cases of this type of model include the Goodman RC association model
and the quasi-variances methodology as implemented by the qvcalc R package.
RCIMs can be defined as a RR-VGLM applied to Y with
For the Goodman RC association model, we have so that
if R = 0 then it is a Poisson regression fitted to a matrix of counts with row effects and column effects; this has a similar idea to a no-interaction two-way ANOVA model.
Another example of a RCIM is if is the identity link and the parameter is the median and the model corresponds to an asymmetric Laplace distribution; then a no-interaction RCIM is similar to a technique called median polish.
In VGAM, rcim() and grc() functions fit the above models.
And also Yee and Hadi (2014)
show that RCIMs can be used to fit unconstrained quadratic ordination
models to species data; this is an example of indirect gradient analysis in
ordination (a topic in statistical ecology).
Vector generalized additive models
Vector generalized additive models (VGAMs) are a major
extension to VGLMs in which the linear predictor is not restricted to be
linear in the covariates but is the
sum of smoothing functions applied to the :
where
These are M additive predictors.
Each smooth function is estimated from the data.
Thus VGLMs are model-driven while VGAMs are data-driven.
Currently, only smoothing splines are implemented in the VGAM package.
For M > 1 they are actually vector splines, which estimate the component functions
in simultaneously.
Of course, one could use regression splines with VGLMs.
The motivation behind VGAMs is similar to
that of
Hastie and Tibshirani (1990)
and
Wood (2017).
VGAMs were proposed in 1996
.
Currently, work is being done to estimate VGAMs using P-splines
of Eilers and Marx (1996)
.
This allows for several advantages over using smoothing splines and vector backfitting, such as the
ability to perform automatic smoothing parameter selection easier.
Quadratic reduced-rank vector generalized linear models
These add on a quadratic in the latent variable to the RR-VGLM class.
The result is a bell-shaped curve can be fitted to each response, as
a function of the latent variable.
For R = 2, one has bell-shaped surfaces as a function of the 2
latent variables---somewhat similar to a
bivariate normal distribution.
Particular applications of QRR-VGLMs can be found in ecology,
in a field of multivariate analysis called ordination.
As a specific rank-1 example of a QRR-VGLM,
consider Poisson data with S species.
The model for Species s is the Poisson regression
for . The right-most parameterization which uses the symbols has particular ecological meaning, because they relate to the species abundance, optimum and tolerance respectively. For example, the tolerance is a measure of niche width, and a large value means that that species can live in a wide range of environments. In the above equation, one would need in order
to obtain a bell-shaped curve.
QRR-VGLMs fit Gaussian ordination models by maximum likelihood estimation, and
they are an example of direct gradient analysis.
The cqo() function in the VGAM package currently
calls optim() to search for the optimal
, and given that, it is easy to calculate
the site scores and fit a suitable generalized linear model to that.
The function is named after the acronym CQO, which stands for
constrained quadratic ordination: the constrained is for direct
gradient analysis (there are environmental variables, and a linear combination
of these is taken as the latent variable) and the quadratic is for the
quadratic form in the latent variables
on the scale.
Unfortunately QRR-VGLMs are sensitive to outliers in both the response
and explanatory variables, as well as being computationally expensive, and
may give a local solution rather than a global solution.
QRR-VGLMs were proposed in 2004.
See also
generalized linear models
R (software)
Regression analysis
Statistical model
Natural exponential family
References
Further reading
Actuarial science
Regression models | Vector generalized linear model | [
"Mathematics"
] | 4,124 | [
"Applied mathematics",
"Actuarial science"
] |
49,136,651 | https://en.wikipedia.org/wiki/MK-4409 | MK-4409 is an experimental drug which acts as a potent and selective inhibitor of the enzyme fatty acid amide hydrolase (FAAH), with an IC50 of 11 nM, and both analgesic and antiinflammatory effects in animal studies. It was studied for the treatment of neuropathic pain and progressed to early stage human clinical trials by 2009.
See also
LY-2183240
URB-597
PF-3845
BIA 10-2474
References
External links
Enzyme inhibitors
Drugs developed by Merck & Co.
Cannabinoids
Abandoned drugs
Oxazoles
Pyridines | MK-4409 | [
"Chemistry"
] | 129 | [
"Drug safety",
"Abandoned drugs"
] |
49,142,274 | https://en.wikipedia.org/wiki/Arcadia%20%28engineering%29 | ARCADIA (Architecture Analysis & Design Integrated Approach) is a system and software architecture engineering method based on architecture-centric and model-driven engineering activities.
History
In the development cycle of a system, former practices focused more on the definition of requirements, their allocation to each component of the system component and associated traceability. Current approaches rather focus on functional analysis, system design, justification of architectural choices, and verification steps. In addition, the design takes into account not only the functional point of view, but also other points of view, which affect the definition and breakdown of the system. For example, constraints relating to system integration, product line management, safety, performance and feasibility. Systems engineering is therefore not just about managing the system requirements, but is a complex design activity.
As an answer to this challenge, the ARCADIA method was created by Thales in 2007, placing architecture and collaboration at the center of systems engineering practices.
The vision for ARCADIA was to break the "walls" between different engineering specializations including architects, development teams, Specialists, IVVQ (Integration, Verification, Validation, and Qualification) Teams, Customer and external partners.
Normalization
The ARCADIA method is about to be standardized as an AFNOR experimental norm. It has been published on March 7, 2018.
Context
The ARCADIA method applies to the design of complex and critical systems, and more generally architectures that are subject to multiple functional and non-functional constraints, including software, electronic, electrical architectures, and industrial processes. It defines a set of practices that guides needs analysis and design to meet an operational requirement. At the same time it is adaptable to the processes and constraints linked to various types of life cycles such as bottom-up approach, application reuse, incremental, iterative and partial development.
Objectives and action means
ARCADIA is a structured engineering method to identify and check the architecture of complex systems. It promotes collaborative work among all stakeholders during many of the engineering phases of the system. It allows iterations during the definition phase that help the architects to converge towards satisfaction of all identified needs.
Even if textual requirements are kept as a support for part of customer need capture, ARCADIA favors functional analysis as the major way to formalize the need and solution behavior. This includes operational, functional and non-functional aspects, along with resulting definition of the architecture, based on – and justified against – this functional analysis.
ARCADIA is based on the following general principles:
All engineering stakeholders share the same language, method set of engineering artifacts and information, description of the need and the product itself as a shared model;
Each set of constraints (e.g. safety, performance, cost, mass, etc.) is formalized in a "viewpoint" against which each candidate architecture will be checked;
Architecture verification rules are established and the model is challenged against them, so as to check that architecture definition meets expectations, as early as possible in the process;
Co-engineering between the different levels of engineering is supported by the joint development of models. Models of various levels of the architecture and trade-offs are deduced, validated and/or connected with each other.
The ARCADIA method is tooled through Capella, a modeling tool that meets full-scale deployment constraints in an operational context. Capella is available free of charge from the engineering community under open source.
Feature summary
The ARCADIA method:
Covers all structured engineering activities, from capturing customer operational needs to system integration verification validation (IVV);
Takes into account multiple engineering levels and their effective collaboration (system, subsystem, software, hardware, etc.);
Integrates co-engineering with specialty engineering (safety, security, performance, interfaces, logistics ...) and IVV;
Provides the ability not only to share descriptive models but also to collaboratively validate properties of the definition and the architecture;
Is field-tested in full-scale industrial applications, and is currently deployed on dozens of major projects in several countries and divisions of Thales.
Methodological approach
One of the difficulties frequently encountered in the development of complex systems comes from the superposition of several partially independent functional chains using shared resources (including but not limited to computing resources). The ARCADIA method and the underlying tools are used to identify functional chains, their overlapping scenarios and desired performance, along with their support by the architecture. Starting with the first level of system analysis, they ensure traceability throughout the process definition and check each proposed architectural design against expected performance and constraints.
The non-functional properties expected from the system solution are also formalized in 'viewpoints'. Each viewpoint captures constraints that the system should face or meet (feared events, security threats, latency expectations, product line or reuse constraints, power consumption or cost issues, and more). Then the architecture model is automatically analyzed to verify that it meets these constraints, thanks to dedicated expert rules (performance computation, resource consumption, safety or security barriers, etc.). This analysis can be done very early in the development cycle, detecting design issues as soon as possible ("early validation").
As a summary, the approach to characterization by views (or "viewpoints") cross-checks that the proposed architecture is capable of providing the required functions with the desired level of performance, security, dependability, mass, scalability, environments, mass, interfaces, etc. ensuring the consistency of engineering decisions, because all engineering stakeholders share the same engineering information, and can apply his/her own views and checks to them, so as to secure the common definition.
Presentation of the approach and key concepts
The first level views used to elaborate and share the architecture model are described below:
"Define the Problem – Customer Operational Need Analysis",
The first step focuses on analysing the customer needs and goals, expected missions and activities, far beyond System/SW requirements. This is expected to ensure good adequacy of System/SW definition with regards to its real operational use – and define IVVQ conditions. Outputs of this step consist mainly in an "operational architecture" describing and structuring this need, in terms of actors/users, their operational capabilities and activities, operational use scenarios giving dimensioning parameters, operational constraints including safety, security, lifecycle, etc.
"Formalisation of System/SW Requirements – System/SW Need Analysis",
The second step focuses now on the system/SW itself, in order to define how it can satisfy the former operational need, along with its expected behaviour and qualities: system/SW functions to be supported and related exchanges, non functional constraints (safety, security...), performances allocated to system boundary, role sharing and interactions between system and operators. It also checks for feasibility (including cost, schedule and technology readiness) of customer requirements, and if necessary gives means to renegotiate their contents. To do this, a first early system/SW architecture (architectural design model) is sketched, from system/SW functional need; then requirements are examined against this architecture in order to evaluate their cost and consistency.
Outputs of this step mainly consist of system/SW functional Need description, interoperability and interaction with the users and external systems (functions, exchanges plus non-functional constraints), and system/SW requirements.
Note that these two steps, which constitute the first part of Architecture building, "specify" the further design, and therefore should be approved/validated with the customer.
"Development of System/SW Architecture – Logical Architecture",
The third step intends to identify the system/SW parts (hereafter called components), their contents, relationships and properties, excluding implementation or technical/technological issues. This constitutes the system/SW logical architecture.
In order for this breakdown in components to be stable in further steps, all major [non-functional] constraints (safety, security, performance, IVV, Cost, non technical, etc.) are taken into account and compared to each other's so as to find the best compromise between them.
This method is described as "Viewpoints-driven", viewpoints being the formalization of the way these constraints impact the system/SW architecture. Outputs of this step consist of the selected logical architecture: components and interfaces definition, including formalization of all viewpoints and the way they are taken into account in the components design.
Since the architecture has to be validated against Need, links with requirements and operational scenarios are also produced.
"Development of System/SW Architecture – Physical Architecture",
The fourth step has the same intents as logical architecture building, except that it defines the "final" architecture of the system/SW at this level of engineering, ready to develop (by lower engineering levels). Therefore, it introduces rationalization, architectural patterns, new technical services and components, and makes the logical architecture evolve according to implementation, technical and technological constraints and choices (at this level of engineering).
Note that the same "Viewpoints-driven" method as for logical architecture building is used for physical architecture definition. Outputs of this step consist of the selected physical architecture: components to be produced, including formalization of all viewpoints and the way they are taken into account in the components design. Links with requirements and operational scenarios are also produced.
"Formalize Components Requirements – Contracts for Development and IVVQ",
The fifth and last step is a contribution to EPBS (End-Product Breakdown Structure) building, taking benefits from the former architectural work, to enforce components requirements definition, and prepare a secured IVVQ.
All choices associated to the system/SW chosen architecture, and all hypothesis and constraints imposed to components and architecture to fit need and constraints, are summarized and checked here.
Outputs from this step are mainly "component Integration contract" collected all necessary expected properties for each component to be developed.
The following figure shows a global view summarizing the recommended technical process, featuring the three elements of the engineering triptych, and their production activities all along the definition and design process.
Communication
As part of the Clarity Project, a book on the ARCADIA method will be published. An introductory document is currently available for download on the Capella website.
The ARCADIA method was presented at various events:
See also
Metamodeling
Model-driven engineering
References
External links
Web page dedicated to the method
Official forum
Thales, founder of the method
Systems engineering | Arcadia (engineering) | [
"Engineering"
] | 2,083 | [
"Systems engineering"
] |
49,142,466 | https://en.wikipedia.org/wiki/Spierings%20Kranen | Spierings Kranen is a Dutch manufacturer of large mobile cranes such as the SK 1265-AT6 "Mighty Tiny" model which can lift up to 10 tons up to 35 metres in height. The company was founded by Leo Spierings and his wife Tiny in 1987.
References
Crane manufacturers
Construction equipment manufacturers of the Netherlands
Dutch brands | Spierings Kranen | [
"Engineering"
] | 73 | [
"Mechanical engineering stubs",
"Mechanical engineering"
] |
49,143,122 | https://en.wikipedia.org/wiki/List%20of%20women%20anthropologists | This is a list of women anthropologists.
See also
List of anthropologists
Anthropologists
Anthropologists
Anthropologists | List of women anthropologists | [
"Technology"
] | 23 | [
"Lists of women in STEM fields",
"Lists of people in STEM fields",
"Women in science and technology"
] |
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