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77,849,243 | https://en.wikipedia.org/wiki/What%20Is%20Real%3F | What Is Real?: The Unfinished Quest for the Meaning of Quantum Physics is a book on quantum physics by American astronomer Adam Becker. It was first published in 2018.
Background
Becker had been a member of the California Quantum Interpretation Network, "a research collaboration among faculty and staff at multiple UC campuses and other universities across California, focusing on the interpretation of quantum physics."
In 2016, he received a grant from the Alfred P. Sloan Foundation to research and publish a written work concerning the history, development, and controversy surrounding the study and development of the mysticized field of Quantum Foundations. The resulting work, What is Real? (2018), focused on the question of what exactly quantum physics says about the nature of reality. Becker, stated the motivation for the book as follows:
Themes
The book deals with the personalities behind the competing interpretations of quantum physics as well as the historical factors that influenced the debate—factors such as military spending on physics research due to World War II, the Cold War ethos that caused the eschewing of physicists thought to be Marxist, the assumed infallibility of John von Neumann, the sexism that quashed the work of Grete Hermann (the female mathematician who first spotted von Neumann's error), and the sway of prominent philosophical schools of the period, like the logical positivists of the Vienna Circle. Niels Bohr appears in the book as the charismatic figure whose stature and obtuse writing style made it hard for alternate interpretations to be voiced. The book also challenges the popular portrayal of Albert Einstein as a behind-the-times thinker who couldn't accept the new paradigm. Becker argues that Einstein's thought experiments aimed at quantum dynamics are not stodgy quibbles with the seeming randomness of quantum physics, as characterized by the popularity of the quote that "God does not play dice". Rather, Einstein's thought experiments are apt critiques of violations of the principle of locality.
Reception
"What is Real?" was given mostly positive reviews by lay and expert audiences alike, including the New York Times, Publishers Weekly, the Wall Street Journal, and New Scientist, among others,.
In Physics Today, philosopher David Wallace called the book "a superb contribution both to popular understanding of quantum theory and to ongoing debates among experts." And in the journal Nature, Ramin Skibba said "What Is Real? is an argument for keeping an open mind. Becker reminds us that we need humility as we investigate the myriad interpretations and narratives that explain the same data." The journal Science explained, "What Is Real? offers an engaging and accessible overview of the debates surrounding the interpretation of quantum mechanics,". Philosopher of science, Tim Maudlin said, "There is no more reliable, careful, and readable account of the whole history of quantum theory in all its scandalous detail."
Physicist Sheldon Glashow wrote a critical review, saying, "I found it distasteful to find a trained astrophysicist invoking a conspiracy by physicists and physics teachers to foist the Copenhagen interpretation upon naive students of quantum mechanics". A review in the journal Science declared the project to be the sporadically accurate presentation of an "oversimplified" summary of either imaginary or merely ostensible conflicts between very complex schools of thought. Reviews in Science News and the American Journal of Physics were also negative, similarly criticizing the book for numerous historical inaccuracies and philosophical oversimplifications.
The book was nominated for the PEN/E. O. Wilson Literary Science Writing Award and Physics World Magazine's Book of the Year Award.
References
2018 non-fiction books
English-language non-fiction books
Popular physics books
Interpretations of quantum mechanics
Basic Books books | What Is Real? | [
"Physics"
] | 760 | [
"Interpretations of quantum mechanics",
"Quantum mechanics",
"Works about quantum mechanics"
] |
77,850,287 | https://en.wikipedia.org/wiki/Periodic%20tense | Periodic tense is a subtype of the grammatical category of tense, which encodes that the event expressed by the verb occurs within a particular period of the day (such as ‘at night’, ‘in the morning’ etc.) or of the year (‘in winter’, ‘in summer’ etc.). Its does not encode a relation to a particular point of reference, unlike deictic tense, the grammatical expression of time reference (usually past, present or future) relative either to the moment of speaking (absolute tense) or to another point of reference (relative tense).
Periodic tense is geographically restricted to Northern America, the Western Amazon region, the Sepik region, Arnhem land and it is almost entirely absent from languages of Africa and Eurasia, which the exception of Chukotkan languages.
Periodic tense in Nez Perce
Periodic tense can be illustrated with data from Nez Perce, which has one of the richest paradigms, comprising matutinal, diurnal, vesperal, nocturnal and hivernal, as illustrated in the following examples
Reconstructibility
Periodic tense systems are at least partially reconstructible in some language families. In proto-Sahaptian for instance, nocturnal *têw- and matutinal *mêy-, from which Nez Perce nocturnal te·w- and matutinal méy- above originate, have been reconstructed by Aoki (1962).
In Tacanan languages, four periodic tense markers are reconstructible, whose reflexes in Cavineña or the following: diurnal -chinepe, nocturnal -sisa, auroral -wekaka and vesperal -apuna (Guillaume 2008:126).
Attested subtypes
16 subtypes of periodic tense markers have been identified in Jacques (2023:7, Table 2), with a latinate terminology for each specific time period.
References
Notes
Bibliography
Aoki, Haruo. 1962. Nez Perce and Northern Sahaptin: A binary comparison. International Journal of American Linguistics 28(3). 172–182.
Aoki, Haruo. 1994. Nez Perce dictionary. University of California publications in linguistics (Vol. 112). Berkeley: University of California Press. .
Bruce, Leslie P. 1979. A grammar of Alamblak (Papua New Guinea). Canberra: Australian National University dissertation.
Cowell, Andrew & Alonzo Sr. Moss. 2006. The Arapaho language. Boulder: University Press of Colorado.
Feldman, Harry. 1986. A grammar of Awtuw. Canberra: Pacific Linguistics.
Guillaume, Antoine. 2008. A grammar of Cavineña. Berlin: Mouton de Gruyter.
Marsault, Julie. 2021. Valency-changing operations in Umóⁿhoⁿ: Affixation, incorporation and syntactic constructions. Paris: Université Paris III dissertation.
Tallman, Adam J. 2018. A grammar of Chácobo (Pano), a southern Pano language of the northern Bolivian Amazon. Austin: University of Texas at Austin dissertation.
Westrum, Peter. 1988. Berik grammar sketch. Irian 16. 133–181.
Grammatical tenses
Time in linguistics
Nez Perce
Tacanan languages | Periodic tense | [
"Physics"
] | 675 | [
"Spacetime",
"Time in linguistics",
"Physical quantities",
"Time"
] |
77,850,423 | https://en.wikipedia.org/wiki/You%20Only%20Look%20Once | You Only Look Once (YOLO) is a series of real-time object detection systems based on convolutional neural networks. First introduced by Joseph Redmon et al. in 2015, YOLO has undergone several iterations and improvements, becoming one of the most popular object detection frameworks.
The name "You Only Look Once" refers to the fact that the algorithm requires only one forward propagation pass through the neural network to make predictions, unlike previous region proposal-based techniques like R-CNN that require thousands for a single image.
Overview
Compared to previous methods like R-CNN and OverFeat, instead of applying the model to an image at multiple locations and scales, YOLO applies a single neural network to the full image. This network divides the image into regions and predicts bounding boxes and probabilities for each region. These bounding boxes are weighted by the predicted probabilities.
OverFeat
OverFeat was an early influential model for simultaneous object classification and localization. Its architecture is as follows:
Train a neural network for image classification only ("classification-trained network"). This could be one like the AlexNet.
The last layer of the trained network is removed, and for every possible object class, initialize a network module at the last layer ("regression network"). The base network has its parameters frozen. The regression network is trained to predict the coordinates of two corners of the object's bounding box.
During inference time, the classification-trained network is run over the same image over many different zoom levels and croppings. For each, it outputs a class label and a probability for that class label. Each output is then processed by the regression network of the corresponding class. This results in thousands of bounding boxes with class labels and probability. These boxes are merged until only one single box with a single class label remains.
Versions
There are two parts to the YOLO series. The original part contained YOLOv1, v2, and v3, all released on a website maintained by Joseph Redmon.
YOLOv1
The original YOLO algorithm, introduced in 2015, divides the image into an grid of cells. If the center of an object's bounding box falls into a grid cell, that cell is said to "contain" that object. Each grid cell predicts B bounding boxes and confidence scores for those boxes. These confidence scores reflect how confident the model is that the box contains an object and how accurate it thinks the box is that it predicts.
In more detail, the network performs the same convolutional operation over each of the patches. The output of the network on each patch is a tuple as follows:where
is the conditional probability that the cell contains an object of class , conditional on the cell containing at least one object.
are the center coordinates, width, and height of the -th predicted bounding box that is centered in the cell. Multiple bounding boxes are predicted to allow each prediction to specialize in one kind of bounding box. For example, slender objects might be predicted by while stout objects might be predicted by .
is the predicted intersection over union (IoU) of each bounding box with its corresponding ground truth.
The network architecture has 24 convolutional layers followed by 2 fully connected layers.
During training, for each cell, if it contains a ground truth bounding box, then only the predicted bounding boxes with the highest IoU with the ground truth bounding boxes is used for gradient descent. Concretely, let be that predicted bounding box, and let be the ground truth class label, then are trained by gradient descent to approach the ground truth, is trained towards , other are trained towards zero.
If a cell contains no ground truth, then only are trained by gradient descent to approach zero.
YOLOv2
Released in 2016, YOLOv2 (also known as YOLO9000) improved upon the original model by incorporating batch normalization, a higher resolution classifier, and using anchor boxes to predict bounding boxes. It could detect over 9000 object categories. It was also released on GitHub under the Apache 2.0 license.
YOLOv3
YOLOv3, introduced in 2018, contained only "incremental" improvements, including the use of a more complex backbone network, multiple scales for detection, and a more sophisticated loss function.
YOLOv4 and beyond
Subsequent versions of YOLO (v4, v5, etc.) have been developed by different researchers, further improving performance and introducing new features. These versions are not officially associated with the original YOLO authors but build upon their work. , there are up to YOLOv8.
See also
Computer vision
Object detection
Convolutional neural network
R-CNN
SqueezeNet
MobileNet
EfficientNet
References
External links
Official YOLO website
YOLO implementation in Darknet
Computer vision
Deep learning
Neural networks | You Only Look Once | [
"Engineering"
] | 994 | [
"Artificial intelligence engineering",
"Packaging machinery",
"Neural networks",
"Computer vision"
] |
77,850,743 | https://en.wikipedia.org/wiki/Crosswall%20construction | Crosswall construction is a building technique that uses prefabricated concrete modules with load-bearing walls that act to communicate the entire weight of the building to its foundation.
References
See also
Curtain wall (architecture)
Types of wall
Building engineering
Construction
Architectural elements | Crosswall construction | [
"Technology",
"Engineering"
] | 52 | [
"Structural engineering",
"Building engineering",
"Construction",
"Types of wall",
"Architectural elements",
"Civil engineering",
"Architecture stubs",
"Components",
"Architecture"
] |
62,476,044 | https://en.wikipedia.org/wiki/Riemann%20Prize | The Riemann Prize is a mathematics prize awarded every three years to outstanding mathematicians between 40 and 65 years of age, given by the Riemann International School of Mathematics in Italy. The award is named in honor of Bernhard Riemann. Established in 2019, it was first awarded to Terence Tao in 2020. It is co-sponsored by the regional government of Lombardy, all public and private universities in the region, and the municipality of Varese.
The winner of the Prize is selected by an international committee, the first one composed by: Enrico Bombieri (IAS), Daniele Cassani (RISM - University of Insubria), S.-Y. Alice Chang (Princeton University), Ron Donagi (University of Pennsylvania), Louis Nirenberg (CIMS - NYU, 1925–2020).
Recipients
See also
List of mathematics awards
Notes
Mathematics awards
Awards established in 2019
Awards with age limits | Riemann Prize | [
"Technology"
] | 185 | [
"Science and technology awards",
"Mathematics awards"
] |
62,478,558 | https://en.wikipedia.org/wiki/Zuzana%20Ke%C4%8Dk%C3%A9%C5%A1ov%C3%A1 | Zuzana Kečkéšová (born 1980) is a Slovak-American molecular biologist at the Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences. She investigates the reasons that certain organs are protected from cancer.
Early life and education
Kečkéšová is from Galanta. She became interested in science as a child and considered becoming an astrophysicist. She studied molecular biology at the Charles University in Prague and graduated in 2003. During her undergraduate degree, she attended the London International Youth Science Forum where she was selected by the British consulate to represent Slovakia. Her research career began in Prague, where she studied the lifecycle of the murine polyomavirus. She became interested in attending Western universities and began her preparation, but did not have the funding to cover her fees. After learning that University College London offered full scholarships to students from Central European countries, Kečkéšová joined University College London in 2003, where she worked toward a doctoral degree in infectious diseases. Her thesis considered retroviral infections and was awarded the Qiagen Award. During her PhD, she spent a year at Columbia University where she looked at post-translational modifications of retroviral restriction factors.
Research and career
After earning her doctorate, Kečkéšová joined the laboratory of Robert Weinberg at Whitehead Institute for Biomedical Research at Massachusetts Institute of Technology. At Massachusetts Institute of Technology Kečkéšová worked on the metabolic processes of cancer cells and the molecular networks of stem cells. Whilst reading the countless scientific studies into the organs that cancer attacks, Kečkéšová became interested in the cells that it did not attack, and began to study cancer metastasis and the mechanisms of tumour growth. She joined the Institute of Organic Chemistry and Biochemistry (IOCB) of the Czech Academy of Sciences in 2017. Kečkéšová discovered that the protein LACTB can act as a tumour suppressant. She demonstrated that activation of LACTB in cancer cells can result in the death of cells; by altering the composition of lipids in cancer mitochondria.
She was awarded a European Molecular Biology Organization (EMBO) Installation Grant to study the vulnerabilities of cancer cells in 2017. In 2018 Kečkéšová was awarded a €1.75 million grant from BTCZ Ventures to support her research into the mechanisms by which cancer impacts the human body. Under the collaboration, Kečkéšová will retain rights to the intellectual property of her research, whilst BTCZ will own licenses for future patents.
Selected publications
Her publications include:
Personal life
Kečkéšová has two children.
References
21st-century Slovak scientists
People from Galanta
Charles University alumni
Alumni of University College London
Molecular biologists
Women molecular biologists
1980 births
Living people
Institute of Organic Chemistry and Biochemistry of the CAS
Slovak biologists | Zuzana Kečkéšová | [
"Chemistry"
] | 564 | [
"Biochemists",
"Molecular biology",
"Molecular biologists"
] |
62,478,649 | https://en.wikipedia.org/wiki/FACOM%20100 | The FACOM 100 was an early electromechanical computer built by Fujitsu in 1954 which used binary-coded decimal arithmetic.
The design of the later FACOM 128 was influenced by experience gained from building the FACOM 100.
See also
FACOM
References
Electro-mechanical computers
1950s computers | FACOM 100 | [
"Technology"
] | 59 | [
"Computing stubs"
] |
62,478,791 | https://en.wikipedia.org/wiki/Women%20in%20Cell%20Biology | Women in Cell Biology (WCIB) is a subcommittee of the American Society for Cell Biology (ASCB) created to promote women in cell biology and present awards.
History
A group of women were unhappy with the lack of recognition in ASCB. In 1971, Virginia Walbot gathered a group of women to meet at the annual ASCB meetings and WICB began. The goal was to provide a space for women to talk and network with other women in the field, learn about job opportunities, and promote women in academia. Newsletters were distributed containing job listings and news of powerful women in biology. Originally, WICB was not accepted by ASCB; the newsletter was not funded and later discontinued in the 1970s. WICB was established as a committee within ASCB in 1994.
Activities
Currently, WICB meets annually at ASCB meetings and has a column in the ASCB newsletter. The goals of WICB are to nominate and give awards and communicate through the newsletter.
Awards
WICB awards the following annually:
WICB Junior Award for Excellence in Research
WICB Mid-Career Award for Excellence in Research
Sandra K. Masur Senior Leadership Award
References
American Society for Cell Biology
Women in science and technology | Women in Cell Biology | [
"Technology"
] | 240 | [
"Women in science and technology"
] |
62,479,274 | https://en.wikipedia.org/wiki/Conjugated%20estrogens/methyltestosterone | Conjugated estrogens/methyltestosterone (CEEs/MT), sold under the brand name Premarin with Methyltestosterone, is a combination of conjugated estrogens (CEEs), an estrogen, and methyltestosterone (MT), an androgen and anabolic steroid (AAR), which is used in menopausal hormone therapy for women. It contains 0.625 to 1.25 mg CEEs and 5 to 10 mg MT. The medication was marketed by Wyeth-Ayerst. CEEs/MT was previously marketed in the United States and Canada. It remains available only in Paraguay, under the brand names Delitan and Delitan Forte.
See also
Esterified estrogens/methyltestosterone
List of combined sex-hormonal preparations
References
Abandoned drugs
Combined estrogen–androgen formulations | Conjugated estrogens/methyltestosterone | [
"Chemistry"
] | 187 | [
"Drug safety",
"Abandoned drugs"
] |
62,480,458 | https://en.wikipedia.org/wiki/Sidorenko%27s%20conjecture | Sidorenko's conjecture is a major conjecture in the field of extremal graph theory, posed by Alexander Sidorenko in 1986. Roughly speaking, the conjecture states that for any bipartite graph and graph on vertices with average degree , there are at least labeled copies of in , up to a small error term. Formally, it provides an intuitive inequality about graph homomorphism densities in graphons. The conjectured inequality can be interpreted as a statement that the density of copies of in a graph is asymptotically minimized by a random graph, as one would expect a fraction of possible subgraphs to be a copy of if each edge exists with probability .
Statement
Let be a graph. Then is said to have Sidorenko's property if, for all graphons , the inequality
is true, where is the homomorphism density of in .
Sidorenko's conjecture (1986) states that every bipartite graph has Sidorenko's property.
If is a graph , this means that the probability of a uniform random mapping from to being a homomorphism is at least the product over each edge in of the probability of that edge being mapped to an edge in . This roughly means that a randomly chosen graph with fixed number of vertices and average degree has the minimum number of labeled copies of . This is not a surprising conjecture because the right hand side of the inequality is the probability of the mapping being a homomorphism if each edge map is independent. So one should expect the two sides to be at least of the same order. The natural extension to graphons would follow from the fact that every graphon is the limit point of some sequence of graphs.
The requirement that is bipartite to have Sidorenko's property is necessary — if is a bipartite graph, then since is triangle-free. But is twice the number of edges in , so Sidorenko's property does not hold for . A similar argument shows that no graph with an odd cycle has Sidorenko's property. Since a graph is bipartite if and only if it has no odd cycles, this implies that the only possible graphs that can have Sidorenko's property are bipartite graphs.
Equivalent formulation
Sidorenko's property is equivalent to the following reformulation:
For all graphs , if has vertices and an average degree of , then .
This is equivalent because the number of homomorphisms from to is twice the number of edges in , and the inequality only needs to be checked when is a graph as previously mentioned.
In this formulation, since the number of non-injective homomorphisms from to is at most a constant times , Sidorenko's property would imply that there are at least labeled copies of in .
Examples
As previously noted, to prove Sidorenko's property it suffices to demonstrate the inequality for all graphs . Throughout this section, is a graph on vertices with average degree . The quantity refers to the number of homomorphisms from to . This quantity is the same as .
Elementary proofs of Sidorenko's property for some graphs follow from the Cauchy–Schwarz inequality or Hölder's inequality. Others can be done by using spectral graph theory, especially noting the observation that the number of closed paths of length from vertex to vertex in is the component in the th row and th column of the matrix , where is the adjacency matrix of .
Cauchy–Schwarz: The 4-cycle C4
By fixing two vertices and of , each copy of that have and on opposite ends can be identified by choosing two (not necessarily distinct) common neighbors of and . Letting denote the codegree of and (i.e. the number of common neighbors), this implies:
by the Cauchy–Schwarz inequality. The sum has now become a count of all pairs of vertices and their common neighbors, which is the same as the count of all vertices and pairs of their neighbors. So:
by Cauchy–Schwarz again. So:
as desired.
Spectral graph theory: The 2k-cycle C2k
Although the Cauchy–Schwarz approach for is elegant and elementary, it does not immediately generalize to all even cycles. However, one can apply spectral graph theory to prove that all even cycles have Sidorenko's property. Note that odd cycles are not accounted for in Sidorenko's conjecture because they are not bipartite.
Using the observation about closed paths, it follows that is the sum of the diagonal entries in . This is equal to the trace of , which in turn is equal to the sum of the th powers of the eigenvalues of . If are the eigenvalues of , then the min-max theorem implies that:
where is the vector with components, all of which are . But then:
because the eigenvalues of a real symmetric matrix are real. So:
as desired.
Entropy: Paths of length 3
J.L. Xiang Li and Balázs Szegedy (2011) introduced the idea of using entropy to prove some cases of Sidorenko's conjecture. Szegedy (2015) later applied the ideas further to prove that an even wider class of bipartite graphs have Sidorenko's property. While Szegedy's proof wound up being abstract and technical, Tim Gowers and Jason Long reduced the argument to a simpler one for specific cases such as paths of length . In essence, the proof chooses a nice probability distribution of choosing the vertices in the path and applies Jensen's inequality (i.e. convexity) to deduce the inequality.
Partial results
Here is a list of some bipartite graphs which have been shown to have Sidorenko's property. Let have bipartition .
Paths have Sidorenko's property, as shown by Mulholland and Smith in 1959 (before Sidorenko formulated the conjecture).
Trees have Sidorenko's property, generalizing paths. This was shown by Sidorenko in a 1991 paper.
Cycles of even length have Sidorenko's property as previously shown. Sidorenko also demonstrated this in his 1991 paper.
Complete bipartite graphs have Sidorenko's property. This was also shown in Sidorenko's 1991 paper.
Bipartite graphs with have Sidorenko's property. This was also shown in Sidorenko's 1991 paper.
Hypercube graphs (generalizations of ) have Sidorenko's property, as shown by Hatami in 2008.
More generally, norming graphs (as introduced by Hatami) have Sidorenko's property.
If there is a vertex in that is neighbors with every vertex in (or vice versa), then has Sidorenko's property as shown by Conlon, Fox, and Sudakov in 2010. This proof used the dependent random choice method.
For all bipartite graphs , there is some positive integer such that the -blow-up of has Sidorenko's property. Here, the -blow-up of is formed by replacing each vertex in with copies of itself, each connected with its original neighbors in . This was shown by Conlon and Lee in 2018.
Some recursive approaches have been attempted, which take a collection of graphs that have Sidorenko's property to create a new graph that has Sidorenko's property. The main progress in this manner was done by Sidorenko in his 1991 paper, Li and Szegedy in 2011, and Kim, Lee, and Lee in 2013.
Li and Szegedy's paper also used entropy methods to prove the property for a class of graphs called "reflection trees."
Kim, Lee, and Lee's paper extended this idea to a class of graphs with a tree-like substructure called "tree-arrangeable graphs."
However, there are graphs for which Sidorenko's conjecture is still open. An example is the "Möbius strip" graph , formed by removing a -cycle from the complete bipartite graph with parts of size .
László Lovász proved a local version of Sidorenko's conjecture, i.e. for graphs that are "close" to random graphs in a sense of cut norm.
Forcing conjecture
A sequence of graphs is called quasi-random with density for some density if for every graph :
The sequence of graphs would thus have properties of the Erdős–Rényi random graph .
If the edge density is fixed at , then the condition implies that the sequence of graphs is near the equality case in Sidorenko's property for every graph .
From Chung, Graham, and Wilson's 1989 paper about quasi-random graphs, it suffices for the count to match what would be expected of a random graph (i.e. the condition holds for ). The paper also asks which graphs have this property besides . Such graphs are called forcing graphs as their count controls the quasi-randomness of a sequence of graphs.
The forcing conjecture states the following:
A graph is forcing if and only if it is bipartite and not a tree.
It is straightforward to see that if is forcing, then it is bipartite and not a tree. Some examples of forcing graphs are even cycles (shown by Chung, Graham, and Wilson). Skokan and Thoma showed that all complete bipartite graphs that are not trees are forcing.
Sidorenko's conjecture for graphs of density follows from the forcing conjecture. Furthermore, the forcing conjecture would show that graphs that are close to equality in Sidorenko's property must satisfy quasi-randomness conditions.
See also
Common graph
References
Graph theory
Conjectures | Sidorenko's conjecture | [
"Mathematics"
] | 1,988 | [
"Unsolved problems in mathematics",
"Graph theory",
"Conjectures",
"Mathematical relations",
"Statements in graph theory",
"Mathematical problems"
] |
62,480,574 | https://en.wikipedia.org/wiki/Alon%E2%80%93Boppana%20bound | In spectral graph theory, the Alon–Boppana bound provides a lower bound on the second-largest eigenvalue of the adjacency matrix of a -regular graph, meaning a graph in which every vertex has degree . The reason for the interest in the second-largest eigenvalue is that the largest eigenvalue is guaranteed to be due to -regularity, with the all-ones vector being the associated eigenvector. The graphs that come close to meeting this bound are Ramanujan graphs, which are examples of the best possible expander graphs.
Its discoverers are Noga Alon and Ravi Boppana.
Theorem statement
Let be a -regular graph on vertices with diameter , and let be its adjacency matrix. Let be its eigenvalues. Then
The above statement is the original one proved by Noga Alon. Some slightly weaker variants exist to improve the ease of proof or improve intuition. Two of these are shown in the proofs below.
Intuition
The intuition for the number comes from considering the infinite -regular tree. This graph is a universal cover of -regular graphs, and it has spectral radius
Saturation
A graph that essentially saturates the Alon–Boppana bound is called a Ramanujan graph. More precisely, a Ramanujan graph is a -regular graph such that
A theorem by Friedman shows that, for every and and for sufficiently large , a random -regular graph on vertices satisfies with high probability. This means that a random -vertex -regular graph is typically "almost Ramanujan."
First proof (slightly weaker statement)
We will prove a slightly weaker statement, namely dropping the specificity on the second term and simply asserting Here, the term refers to the asymptotic behavior as grows without bound while remains fixed.
Let the vertex set be By the min-max theorem, it suffices to construct a nonzero vector such that and
Pick some value For each vertex in define a vector as follows. Each component will be indexed by a vertex in the graph. For each if the distance between and is then the -component of is if and if We claim that any such vector satisfies
To prove this, let denote the set of all vertices that have a distance of exactly from First, note that
Second, note that
where the last term on the right comes from a possible overcounting of terms in the initial expression. The above then implies
which, when combined with the fact that for any yields
The combination of the above results proves the desired inequality.
For convenience, define the -ball of a vertex to be the set of vertices with a distance of at most from Notice that the entry of corresponding to a vertex is nonzero if and only if lies in the -ball of
The number of vertices within distance of a given vertex is at most Therefore, if then there exist vertices with distance at least
Let and It then follows that because there is no vertex that lies in the -balls of both and It is also true that because no vertex in the -ball of can be adjacent to a vertex in the -ball of
Now, there exists some constant such that satisfies Then, since
Finally, letting grow without bound while ensuring that (this can be done by letting grow sublogarithmically as a function of ) makes the error term in
Second proof (slightly modified statement)
This proof will demonstrate a slightly modified result, but it provides better intuition for the source of the number Rather than showing that we will show that
First, pick some value Notice that the number of closed walks of length is
However, it is also true that the number of closed walks of length starting at a fixed vertex in a -regular graph is at least the number of such walks in an infinite -regular tree, because an infinite -regular tree can be used to cover the graph. By the definition of the Catalan numbers, this number is at least where is the Catalan number.
It follows that
Letting grow without bound and letting grow without bound but sublogarithmically in yields
References
Algebraic graph theory
Spectral theory | Alon–Boppana bound | [
"Mathematics"
] | 836 | [
"Mathematical relations",
"Graph theory",
"Algebra",
"Algebraic graph theory"
] |
62,480,647 | https://en.wikipedia.org/wiki/Mining%20sludge | Mining sludge is the waste product of alluvial mining, and in particular hydraulic sluicing. It has been particularly prominent in gold fields in Australia and California in the nineteenth century.
In the 1840s in California and 1850s in Australia, methods for extracting alluvial gold were developed which involved washing soil and gravel through sluice boxes using diverted streams and other water sources. The waste or tailings were released into the waterways forming large deposits of highly mobile sediment. This 'sludge' as it was generally termed, blocked the stream channels causing flooding and burial of land downstream.
The cyanide process also involved releasing sediment contaminated with cyanide, while other sludge deposits have a variety of contaminants used in the mining process.
Large areas of land were affected by sludge, particularly in Victoria, where a Royal Commission was established in 1858-9 to investigate and manage the problem. This resulted in a number of regulations and the construction of large stone-lined sludge channels to concentrate and divert the sludge away from settled areas and buildings. the towns of Bendigo, Ballarat, Castlemaine, Creswick and Maryborough have channelized streams running through them as a result.
Ultimately hydraulic sluicing was banned in 1904 as a result of the continuing environmental damage caused to waterways in places such as Omeo, and a Sludge Abatement Board was established to regulate and repair the problem.
References
History of mining in Australia
Surface mining
Hydraulic engineering
Australian gold rushes | Mining sludge | [
"Physics",
"Engineering",
"Environmental_science"
] | 304 | [
"Hydrology",
"Physical systems",
"Hydraulics",
"Civil engineering",
"Hydraulic engineering"
] |
62,480,929 | https://en.wikipedia.org/wiki/Katherine%20Faber | Katherine T. Faber is an American materials scientist and one of the world's foremost experts in ceramic engineering, material strengthening, and ultra-high temperature materials. Faber is the Simon Ramo Professor of Materials Science at the California Institute of Technology (Caltech). She was previously the Walter P. Murphy Professor and department chair of Materials Science and Engineering at the McCormick School of Engineering and Applied Science at Northwestern University.
Faber is known for her work in the fracture mechanics of brittle materials and energy-related ceramics and composites, including the Faber-Evans model of crack deflection which is named after her. Her research encompasses a broad range of topics, from ceramics for thermal and environmental barrier coatings in power generation components to porous solids for filters and flow in medical applications. Faber is the co-founder and previous co-director of the Center for Scientific Studies in the Arts and also oversees a number of collaborative endeavors, especially with NASA's Jet Propulsion Laboratory.
Biography
Early life and education
Faber was the youngest daughter of an aspiring aeronautical engineer whose education was halted by the Great Depression. As the only one of her siblings who had an interest in the sciences, she was encouraged by her father to pursue an education in engineering. An initial interest in chemistry evolved to an appreciation for ceramic engineering after Faber recognized its potential in solving many engineering problems. Faber eventually obtained her Bachelor of Science in Ceramic Engineering at the New York State College of Ceramics within Alfred University (1975). She completed her Master of Science in Ceramic Science at Penn State University (1978) where she studied phase separation in glasses with Professor Guy Rindone. After graduating with her MS, she worked for a year as a development engineer for The Carborundum Company in Niagara Falls, New York, on the development of silicon carbide for high performance applications such as engines. Following her year in industry, Faber decided to pursue a PhD in Materials Science at the University of California, Berkeley, which she completed in 1982.
Teaching, recognition
From 1982 to 1987, Faber served as Assistant and Associate Professor of Ceramic Engineering at the Ohio State University. She participated in the first class of the Defense Science Study Group, a program which introduces outstanding American science and engineering professors to the United States’ security challenges (1985–1988). From 1988 to 2014, she taught as Associate Professor, professor, and Walter P. Murphy Professor of Materials Science and Engineering at the McCormick School of Engineering at Northwestern University. During her time at Northwestern, she served as the Associate Dean for Graduate Studies and Research, overseeing more than $25 million in faculty research funds. She went on to complete a 5-year term as department chair of Materials Science and Engineering at Northwestern, where she also served as the Chair of the University Materials Council (2001–2002), a collaborative group composed of directors of a number of materials programs from across the US and Canada. Additionally, from 2005 to 2007 she sat on the Scientific Advisory Committee of the Advanced Photon Source at Argonne National Lab. In 2014, she joined the teaching faculty at Caltech.
From 2006 to 2007, Faber served as the President of the American Ceramic Society, and in 2013 was named a Distinguished Life Member in recognition of her notable contributions to the ceramic and glass profession. In 2014, Faber was elected to the American Academy of Arts and Sciences class of fellows. In 2024, Faber received the W. David Kingery Award, one of the highest honors bestowed in the ceramics community, for her lifelong contributions to ceramic technology and education.
She has also been recognized with:
IBM faculty development award (1984–1986)
National Science Foundation (NSF) Presidential Young Investigator Award (1984–1989)
Society of Women Engineers Distinguished Educator Award (1995)
YWCA Achievement Award for Education (1997)
NSF Creativity Extension Award (2001–2003)
Fellowship in ASM International (2003)
Pennsylvania State University College of Earth and Mineral Sciences Charles L. Hosler Alumni Scholar Medal (2004)
NSF American Competitiveness and Innovation Fellow and Creativity Extension Award (2010)
Toledo Glass and Ceramics Award, Michigan/Northwest Ohio Section of the American Ceramic Society (2012)
American Academy of Arts and Sciences (2014)
American Ceramic Society John Jeppson Award (2015)
W. David Kingery Award (2024)
Work
Research
Katherine Faber's research encompasses a diverse range of material science topics, focusing on fracture mechanics, shape memory materials, environmental barrier coatings (EBCs), additive manufacturing, boron nitride composites, and historical ceramics. Her work on shape memory materials investigates the martensitic transformation in zirconia-based ceramics. Using freeze-casting techniques, Faber's research group creates porous zirconia structures exhibiting shape memory behaviors. Through sol-gel synthesis and freeze-casting, she examines stress-induced shape memory and superelastic effects in oligocrystalline zirconia systems, addressing the volume change issue that causes premature cracking in bulk systems.Faber also explores the durability of environmental barrier coatings (EBCs) in high-temperature applications, such as gas turbine engines. EBCs are essential for protecting ceramic matrix composites (CMCs) from degradation in combustion environments. Her research delves into the damage modes, including oxidation of the bond coat layer and the mismatch of thermal expansion coefficients, which lead to cracking and spalling. Faber employs advanced techniques like high-intensity X-rays at the Advanced Photon Source (APS) to measure internal strains, stresses, and damage evolution in EBC systems, aiming to understand the mechanisms and rates of oxidation failure and enhance the lifetime of these coatings.
In collaboration with NASA's Jet Propulsion Laboratory, Faber works on advancing Hall-effect thrusters by developing a composite material that combines hexagonal boron nitride (h-BN) and graphite. The brittle nature of bulk BN poses challenges under dynamic loads, prompting Faber's group to create a layered system where h-BN is grown on graphite through high-temperature carbothermal reduction. This composite material combines the desirable properties of both components, offering thermal emissivity, chemical inertness, and resistance to thermal shock while addressing the issues of oxidation and brittleness in dynamic environments.
Faber's research group also examines historical ceramics, specifically Meissen porcelain, to understand and authenticate Böttger lusterware. Using scientific methods such as X-ray diffraction, scanning electron microscopy, and chemical characterization, her group investigates the composition and manufacturing techniques of lusterware. By reverse-engineering these historical artifacts, her research provides insights into the materials and processes used in early 18th-century Meissen factories, contributing to the historical knowledge and preservation of these significant cultural artifacts. Her research interests also include silicon-based ceramics and ceramic matrix composites; polymer-derived multifunctional ceramics; graphite- and silicon carbide-based cellular ceramics synthesized from natural scaffolds, such as pyrolyzed wood; and cultural heritage science, with emphasis on porcelains and jades.
Crack Deflection Model
Main Article: Faber-Evans modelKatherine Faber and her PhD advisor, Anthony G. Evans, first introduced a materials of mechanics model designed to predict the enhancement of fracture toughness in ceramics. This is achieved by accounting for crack deflection around second-phase particles prone to microcracking within a matrix. The model considers particle morphology, aspect ratio, spacing, and volume fraction of the second phase. Additionally, it accounts for the decrease in local stress intensity at the crack tip when deflection or bowing of the crack plane occurs.
Faber showed that by using imaging techniques, the actual crack tortuosity can be determined, enabling the direct input of deflection and bowing angles into the model. The subsequent rise in fracture toughness is then contrasted with that of a flat crack in a plain matrix. The degree of toughening hinges on the mismatch strain resulting from thermal contraction incompatibility and the microfracture resistance at the particle/matrix interface. This toughening effect becomes prominent when particles exhibit a narrow size distribution and are suitably sized.
Faber's analysis revealed that fracture toughness, regardless of morphology, is primarily determined by the most severe twisting of the crack front rather than its initial inclination. While the initial tilting of the crack front contributes to significant toughening in the case of disc-shaped particles, the twist component remains the dominant factor in enhancing toughness. Additionally, she showed that the distribution of inter-particle spacing plays a crucial role in the toughening effect of spherical particles. Specifically, the toughness increases when spheres are in close proximity, causing twist angles to approach π/2. These insights by Faber formed the foundation for designing stronger two-phase ceramic materials. The Faber-Evans model is widely used by materials scientists to indicate that materials with approximately equiaxial grains can experience a fracture toughness increase of about twice the grain boundary value due to deflection effects.
Initiatives
Faber is the co-founder and co-director of the Northwestern University–Art Institute of Chicago Center for Scientific Studies in the Arts (NU-ACCESS), a collaboration between Northwestern University and the Art Institute of Chicago in which advanced materials characterization and analytical techniques are used to further conservation science for historical artifacts. NU-ACCESS, the first center of its kind, provides opportunities for scientists and scholars from a variety of institutions to make use of the center's facilities to study their collections.
Personal life
Faber is married to condensed matter physicist, and current president of the California Institute of Technology, Thomas F. Rosenbaum. They began their careers at the California Institute of Technology in 2013 after Rosenbaum transitioned from his previous position as the John T. Wilson Distinguished Service Professor of Physics and university provost of The University of Chicago. Together, they have two sons, Daniel and Michael.
See also
Faber-Evans model
Ceramic engineering
Fracture
Fracture toughness
Toughening
Selected publications
Faber has authored over 150 papers, written three book chapters, and edited a book, Semiconductors and Semimetals: The Mechanical Properties of Semiconductors v. 37. In 2003, She was recognized by the Institute for Scientific Information as a Highly Cited Author in Materials Science.
Chari, C. S. and Faber, K. T. (2022) Oxidation resistance of AlN/BN via mullite-type Al₁₈B₄O₃₃. Journal of the European Ceramic Society, 42 (8). pp. 3437–3445. ISSN 0955-2219. https://resolver.caltech.edu/CaltechAUTHORS:20220222-706520000
Chari, C.S., Taylor, Z.W., Bezur, A., Xie, S. and Faber, K.T., 2022. Nanoscale engineering of gold particles in 18th century Böttger lusters and glazes. Proceedings of the National Academy of Sciences, 119(18), p.e2120753119.
Harder, Bryan J. and Good, Brian and Schmitt, Michael et al. (2022) Deposition of electrically conductive zirconium monoxide via plasma spray-physical vapor deposition. Journal of the American Ceramic Society, 105 (5). pp. 3568–80. ISSN 0002-7820. https://resolver.caltech.edu/CaltechAUTHORS:20220121-733841000
Arai, Noriaki and Faber, Katherine T. (2021) Freeze-cast honeycomb structures via gravity-enhanced convection. Journal of the American Ceramic Society, 104 (9). pp. 4309–4315. ISSN 0002-7820. https://resolver.caltech.edu/CaltechAUTHORS:20210504-120148263
Kuo, Taijung and Rueschhoff, Lisa M. and Dickerson, Matthew B. et al. (2021) Hierarchical porous SiOC via freeze casting and self-assembly of block copolymers. Scripta Materialia, 191 . pp. 204–209. ISSN 1359-6462. https://resolver.caltech.edu/CaltechAUTHORS:20201019-100031049
Faber, K.T., Casadio, F., Masic, A., Robbiola, L. and Walton, M., 2021. Looking Back, Looking Forward: Materials Science in Art, Archaeology, and Art Conservation. Annual Review of Materials Research, 51, pp. 435–460.
Brodnik, N.R., Brach, S., Long, C.M., Ravichandran, G., Bourdin, B., Faber, K.T. and Bhattacharya, K., 2021. Fracture Diodes: Directional asymmetry of fracture toughness. Physical Review Letters, 126(2), p. 025503.
Zeng, Xiaomei and Martinolich, Andrew J. and See, Kimberly A. et al. (2020) Dense garnet-type electrolyte with coarse grains for improved air stability and ionic conductivity. Journal of Energy Storage, 27 . Art. No. 101128. ISSN 2352-152X. https://resolver.caltech.edu/CaltechAUTHORS:20191224-093208324
Brodnik, N.R., Hsueh, C.J., Faber, K.T., Bourdin, B., Ravichandran, G. and Bhattacharya, K., 2020. Guiding and trapping cracks with compliant inclusions for enhancing toughness of brittle composite materials. Journal of Applied Mechanics, 87(3), p. 031018.
Sturdy, L.F., Wright, M.S., Yee, A., Casadio, F., Faber, K.T. and Shull, K.R., 2020. Effects of zinc oxide filler on the curing and mechanical response of alkyd coatings. Polymer, 191, p. 122222.
Brodnik, N. R. and Schmidt, J. and Colombo, P. et al. (2020) Analysis of Multi-scale Mechanical Properties of Ceramic Trusses Prepared from Preceramic Polymers. Additive Manufacturing, 31 . Art. No. 100957. ISSN 2214-8604. https://resolver.caltech.edu/CaltechAUTHORS:20191120-091827034
Buannic, L., Naviroj, M., Miller, S.M., Zagorski, J., Faber, K.T. and Llordés, A., 2019. Dense freeze‐cast Li7La3Zr2O12 solid electrolytes with oriented open porosity and contiguous ceramic scaffold. Journal of the American Ceramic Society, 102(3), pp. 1021–29.
Tan, W.L., Faber, K.T. and Kochmann, D.M., 2019. In-situ observation of evolving microstructural damage and associated effective electro-mechanical properties of PZT during bipolar electrical fatigue. Acta Materialia, 164, pp. 704–13.
Stolzenburg, F., Kenesei, P., Almer, J., Lee, K.N., Johnson, M.T. and Faber, K.T., 2016. The influence of calcium–magnesium–aluminosilicate deposits on internal stresses in Yb2Si2O7 multilayer environmental barrier coatings. Acta Materialia, 105, pp. 189–98.
Naviroj, M., Miller, S.M., Colombo, P. and Faber, K.T., 2015. Directionally aligned macroporous SiOC via freeze casting of preceramic polymers. Journal of the European Ceramic Society, 35(8), pp. 2225–2232.
Stolzenburg, F., Johnson, M.T., Lee, K.N., Jacobson, N.S. and Faber, K.T., 2015. The interaction of calcium–magnesium–aluminosilicate with ytterbium silicate environmental barrier materials. Surface and Coatings Technology, 284, pp. 44–50.
Shanti, N.O., Chan, V.W., Stock, S.R., De Carlo, F., Thornton, K. and Faber, K.T., 2014. X-ray micro-computed tomography and tortuosity calculations of percolating pore networks. Acta Materialia, 71, pp. 126–35.
Chen-Wiegart, Y.C.K., Liu, Z., Faber, K.T., Barnett, S.A. and Wang, J., 2013. 3D analysis of a LiCoO2–Li (Ni1/3Mn1/3Co1/3) O2 Li-ion battery positive electrode using x-ray nano-tomography. Electrochemistry Communications, 28, pp. 127–30.
Liu, Z., Cronin, J.S., Yu-chen, K., Wilson, J.R., Yakal-Kremski, K.J., Wang, J., Faber, K.T. and Barnett, S.A., 2013. Three-dimensional morphological measurements of LiCoO2 and LiCoO2/Li (Ni1/3Mn1/3Co1/3) O2 lithium-ion battery cathodes. Journal of Power Sources, 227, pp. 267–74.
Harder, B.J., Ramìrez‐Rico, J., Almer, J.D., Lee, K.N. and Faber, K.T., 2011. Chemical and mechanical consequences of environmental barrier coating exposure to calcium–magnesium–aluminosilicate. Journal of the American Ceramic Society, 94, pp.s178-s185.
Johnson, M.T. and Faber, K.T., 2011. Catalytic graphitization of three-dimensional wood-derived porous scaffolds. Journal of Materials Research, 26(1), pp. 18–25.
Kaul, V.S., Faber, K.T., Sepulveda, R., de Arellano López, A.R. and Martinez-Fernandez, J., 2006. Precursor selection and its role in the mechanical properties of porous SiC derived from wood. Materials Science and Engineering: A, 428(1–2), pp. 225–32.
Seitz, M.E., Burghardt, W.R., Faber, K.T. and Shull, K.R., 2007. Self-assembly and stress relaxation in acrylic triblock copolymer gels. Macromolecules, 40(4), pp. 1218–26.
Pappacena, K.E., Faber, K.T., Wang, H. and Porter, W.D., 2007. Thermal conductivity of porous silicon carbide derived from wood precursors. Journal of the American Ceramic Society, 90(9), pp. 2855–62.
Su, Y.J., Trice, R.W., Faber, K.T., Wang, H. and Porter, W.D., 2004. Thermal conductivity, phase stability, and oxidation resistance of Y3Al5O12 (YAG)/Y2O3–ZrO2 (YSZ) thermal-barrier coatings. Oxidation of metals, 61(3), pp. 253–71.
Trice, R.W., Su, Y.J., Mawdsley, J.R., Faber, K.T., Arellano-López, D., Wang, H. and Porter, W.D., 2002. Effect of heat treatment on phase stability, microstructure, and thermal conductivity of plasma-sprayed YSZ. Journal of materials science, 37(11), pp. 2359–65.
References
Living people
Place of birth missing (living people)
Women materials scientists and engineers
American materials scientists
California Institute of Technology faculty
Alfred State College alumni
Penn State College of Earth and Mineral Sciences alumni
University of California, Berkeley alumni
Northwestern University faculty
21st-century American scientists
21st-century American women scientists
20th-century American scientists
20th-century American women scientists
American women academics
1953 births | Katherine Faber | [
"Materials_science",
"Technology"
] | 4,293 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
62,482,538 | https://en.wikipedia.org/wiki/Seasons%20on%20planets | The start and end dates of a season on any planet of the Solar System depends on same factors valid on Earth, but which have different values on different planets:
North Pole direction (rotation axis direction)
Vernal equinox direction
Orbit eccentricity
Year duration
Orbit plane inclination
All these factors affect how much energy from Sun falls on all the points at a same given latitude (i.e. a parallel) on the planet during daytime; if such amount of energy changes during the year, the planet has seasons.
North Pole and rotation axis
If the rotation axis of the planet is not perpendicular to the orbit plane, the incidence of the Sun on each point of planet surface will change during the year, which is the main reason of existence of seasons.
Equinox direction
Given the different Sun incidence in different positions in the orbit, it is necessary to define a standard point of the orbit of the planet, to define the planet position in the orbit at each moment of the year w.r.t such point; this point is called with several names: vernal equinox, spring equinox, March equinox, all equivalent, and named considering northern hemisphere seasons. This point is defined as the point in the celestial sphere where the Sun appears in a specific moment of the year:
the date is one of the two of the equinoxes on the planet, when daytime and nighttime are of approximately equal duration all over the planet. The word is derived from the Latin 'aequinoctium', from 'aequus' (equal) and 'nox' (genitive 'noctis') (night).
in that date the apparent position of Sun in the sky (subsolar point) appears to leave the Southern Hemisphere and to cross the celestial equator, heading northward as seen from the planet. The date when instead the subsolar point appears to cross the equator southward is the other equinox, named autumn equinox. There are only two equinoxes in one year.
Orbit eccentricity
Orbit eccentricity causes the planet/Sun distance to change during the year: The higher is the eccentricity, the higher is the change; Sun rays intensity in various moments of the year changes as the planet/Sun distance changes. Earth eccentricity is very low (0.0167 in a scale from 0 to 1.0000), hence it does not affect so much temperature changes during the year.
Year duration
Conventionally one year is divided in 4 seasons, hence their duration is different if the year duration in Earth days is different.
Data needed for the determination of planets seasons
Direction of north pole / rotation axis of Solar System planets
From inclination of rotation axis it depends the direction of vernal equinox.
Orbital planes inclinations
Orbital eccentricities
Synodic periods (years durations)
References
Astrometry | Seasons on planets | [
"Astronomy"
] | 580 | [
"Astrometry",
"Astronomical sub-disciplines"
] |
62,482,960 | https://en.wikipedia.org/wiki/Glasfabrik%20Lamberts | Glasfabrik Lamberts was established in 1887 by Laurenz Lamberts and is managed by the fourth generation of the family to the present day. The Glashütte is the only independent glass factory in the world to produce all four types of cast glass. Lamberts is the only glass factory in Germany and Europe to manufacture profiled glass in all production stages within Europe. The company’s headquarters and production plant are located in Holenbrunn, a suburb of Wunsiedel in the Fichtelgebirge region.
History
Laurenz Lamberts bought the company premises on 23 May 1887 and founded the Glasfabrik in the same year. He did not choose Wunsiedel at random. One reason for the location was the regionally available raw materials. Even today the resources used for production come directly from the region. The second important reason was the expansion of the railway line between Regensburg and Hof and the connection to Holenbrunn. The station was essential for the company in terms of transporting its glass products.
Production
Glasfabrik Lamberts is the only independent manufacturer of cast glass to produce profile glass, ornamental glass, wired glass and antimony-free solar glass.
Since 1996 the company has manufactured all its types of glass with the aid of an oxygen-fired glass melting furnace and sold them as EcoGlass, and it still the only producer of architectural glass to do so. Up to 50% waste glass is used in the various glass products and 100% of the glass waste is recycled. Since 2011 the entire production facility and offices have been completely powered by green electricity from Bavarian hydroelectric power plants.
Big Ben
During the Big Ben's 2017 renovation, the original Victorian glass plates used for the dials were removed and replaced with faithful reproductions made in Germany by Glasfabrik Lamberts.
External links
Official Website
References
Glass production
1887 establishments in Germany
1887 establishments in Bavaria
German brands
Glassmaking companies of Germany | Glasfabrik Lamberts | [
"Materials_science",
"Engineering"
] | 399 | [
"Glass engineering and science",
"Glass production"
] |
62,484,990 | https://en.wikipedia.org/wiki/Developmental%20neuropsychology | Developmental neuropsychology combines the fields of neuroscience and developmental psychology, while drawing from various other related disciplines. It examines the relationship of behavior and brain function throughout the course of an individual's lifespan, though often emphasis is put on childhood and adolescence when the majority of brain development occurs. Research tends to focus on development of important behavioral functions like perception, language, and other cognitive processes. Studies in this field are often centered around children or other individuals with developmental disorders or various kinds of brain related trauma or injury. A key concept of this field is that looks at and attempts to relate the psychological aspects of development, such as behavior, comprehension, cognition, etc., to the specific neural structures; it draws parallels between behavior and mechanism in the brain. Research in this field involves various cognitive tasks and tests as well as neuroimaging. Some of the many conditions studied by developmental neuropsychologists include congenital or acquired brain damage, autism spectrum disorder, attention deficit disorder, executive dysfunction, seizures, intellectual disabilities, obsessive compulsive disorder, stuttering, schizophrenia, developmental aphasia, and other learning delays such as dyslexia, dysgraphia, and dyspraxia.
History
Alexander Luria is considered by some to be a founding father of the field of neuropsychology. Luria's work, much of which was related to speech rehabilitation, provided much of the foundation for what we know today as child neuropsychology (developmental neuropsychology focusing only on beginning of lifespan). The Luria-Nebraska Neuropsychological Battery, a standardized test of neuropsychological functioning, was created based on his ideas. Lev Vygotsky, a student of Luria, also made significant contributions to child neuropsychology. Together, their methods have developed the basis for what is known as the Vygotsky-Luria approach. This approach is characterized by the idea that "higher psychological functions are characterized by three main features: (1) social genesis; (2) system structure; and (3) dynamic organization and localization" and examines the neural organization and function structure behind these higher mental functions.
Over time, completion of education to at least the high school level has become increasingly common as more and more jobs require skills such as reading and writing. As pressure to have children complete their schooling increases, so has the pressure to provide adequate education to all children. This has led to laws whose aim is to ensure education for disabled students. In order to accomplish this, research focus began to shift from adults who were skilled or struggled to read and write to the developmental processes behind them.
Subfields
Research in developmental neuropsychology can generally be divided into two categories that are based on two main goals of the field: educational and clinical. The educational approach aims to understand and aid in the education of developing children (or in some cases adults) whom have deficits learning certain skills, most commonly language related – reading and writing. While some studies do focus on children with brain damage, a lot can be learned from children without brain damage who struggle to learn specific skills and/or have learning disabilities. The goal of this research is to understand the neural causes of these problems and how they relate to the psychological aspects of it in order to improve education programs and treatments. The clinical approach has a greater focus on pathology and medical treatments and diagnoses. Often these studies evaluate and describe a patient's neural damage due to injury, brain tumors, seizures, or various congenital disorders. This type of research typically examines loss of certain functions due to damage and assesses to what extent if any can patients, usually children with still developing brains, can regain these functions. The objective of a neuropsychological evaluation is to have a comprehensive view of a child's overall functioning, including how their brain operates, their strengths and limitations, their preferred learning style, and any potential abnormalities. This process is essential in the evaluation for the medical provider.
References
Neurology
Neuropsychology
Developmental psychology | Developmental neuropsychology | [
"Biology"
] | 832 | [
"Behavioural sciences",
"Behavior",
"Developmental psychology"
] |
62,485,335 | https://en.wikipedia.org/wiki/Doppler%20parameter | The Doppler parameter, or Doppler broadening parameter, usually denoted as , is a parameter commonly used in astrophysics to characterize the width of observed spectral lines of astronomical objects. It is defined as
,
where is the one-dimensional velocity dispersion . Given this parameter, the velocity distribution of the line-emitting/absorbing atoms and ions proximated by a Gaussian can be rewritten as
,
where is the probability of the velocity along the line of sight being in the interval .
The line width is also often specified in terms of the FWHM (full width at half maximum), which is
.
Distribution
The Doppler parameters of Lyman-alpha forest absorption lines are in the range 10–100 km s−1, with a median value around that decrease with redshift . Analyses of the HST/COS dataset of low-redshift quasars gives a median parameter of around (, ).
See also
Doppler broadening
Doppler spectroscopy
References
Doppler effects
Astronomical spectroscopy | Doppler parameter | [
"Physics",
"Chemistry"
] | 215 | [
"Physical phenomena",
"Spectrum (physical sciences)",
"Astrophysics",
"Astronomical spectroscopy",
"Doppler effects",
"Spectroscopy"
] |
62,485,379 | https://en.wikipedia.org/wiki/34%20Pegasi | 34 Pegasi is a triple star system in the northern constellation of Pegasus. It has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.76. The system is located at a distance of 131 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −13.5 km/s. It has been catalogued as a member of the Hyades Supercluster, although its membership status remains doubtful.
The innermost system is a single-lined spectroscopic binary with an orbital period of and an eccentricity of 0.44. The orbital plane of this pair is being viewed nearly edge-on, and has an angular semimajor axis of . A third member of the system has a poorly-constrained 420 year orbit around the main pair. This star was discovered by Burnham in 1874, and the discovery code BU 290 was given to the double. As of 2015, it lies at an angular separation of along a position angle of from the inner system.
The primary member, component Aa, is an F-type main-sequence star that is starting to evolve off the main sequence, with stellar classifications of F7V or F8IV−V, depending on the source. It is around three billion years old and is spinning with a projected rotational velocity of 8 km/s, with a measured rotation period of 12 days. The star has 1.3 times the mass of the Sun and 2.25 times the Sun's radius. It is radiating 6.7 times the luminosity of the Sun from its photosphere at an effective temperature of 6,200 K.
The secondary companion to the primary, component Ab, is most likely a red dwarf star with around 29% of the mass of the Sun. The tertiary member, component B, has 53% of the Sun's mass and a class of around K4.
References
F-type main-sequence stars
Spectroscopic binaries
Triple stars
Hyades Stream
Pegasus (constellation)
Durchmusterung objects
212754
62523 | 34 Pegasi | [
"Astronomy"
] | 430 | [
"Pegasus (constellation)",
"Constellations"
] |
62,485,831 | https://en.wikipedia.org/wiki/Ted%20Janssen | Theo Willem Jan Marie Janssen (13 August 1936 – 29 September 2017), better known as Ted Janssen, was a Dutch physicist and Full Professor of Theoretical Physics at the Radboud University Nijmegen. Together with Pim de Wolff and Aloysio Janner, he was one of the founding fathers of N-dimensional superspace approach in crystal structure analysis for the description of quasi periodic crystals and modulated structures. For this work he received the Aminoff Prize of the Royal Swedish Academy of Sciences (together with de Wolff and Janner) in 1988 and the Ewald Prize of the International Union of Crystallography (with Janner) in 2014. These achievements were merit of his unique talent, combining a deep knowledge of physics with a rigorous mathematical approach. Their theoretical description of the structure and symmetry of incommensurate crystals using higher dimensional superspace groups also included the quasicrystals that were discovered in 1982 by Dan Schechtman, who received the Nobel Prize in Chemistry in 2011. The Swedish Academy of Sciences explicitly mentioned their work at this occasion.
Early life and education
Ted Janssen was born on August 13, 1936, in Vught, near 's-Hertogenbosch in the Netherlands. Already as a young boy he was fascinated by the sciences. He built radios, set up a chemistry lab in the attic of his parental home, was an avid bird watcher and he built his own telescopes. He remembered high school as ‘not very inspiring’ and he passed all exams without much effort, but viewed it as a time that truly formed him. Instead of spending time on homework he studied the history and philosophy of science and was very interested in astronomy and astrophysics.
During his high school years he also developed a deep appreciation of literature and music. Later he added the visual arts, ballet, and architecture to that list. The enjoyment of the arts was vital to Ted. He called it essential components of life. He started playing the piano, harpsichord and cello in his early twenties. Too late to become an accomplished musician, but it brought him great joy.
In 1954 he started college in Utrecht, studying mathematics and physics with minors in chemistry and astronomy. He again showed his interest in a wide variety of topics by attending lectures in ethics, philosophy, music and sculpture. After his candidate degree he concentrated on theoretical physics, but always included a deep understanding of mathematics in his work.
After studying theoretical physics in Utrecht University Ted graduated under Leon van Hove with his doctoral dissertation ‘the classical limit of quantum mechanical diagram expansions’ and he was offered the opportunity to present it at an international conference in Utrecht on ‘Many-body Problems’. No less than six Nobel laureates (Yang, Lee, Prigogine, Anderson, Cooper and Schrieffer) were in the audience for Ted’s first presentation, which led to his first publication as well: ’On the classical limit of the diagram expansion in quantum statistics’ by T.W.J.M. Janssen. All his later publications were published as T. Janssen or Ted Janssen.
After his doctoral exam in 1960 Ted worked for several years with professors Theo Ruijgrok, Tini Veltman, and John Tjon in Utrecht. Earlier he developed a friendship with co-student and co-worker Geert Fast. Geert’s promotor van Hove moved from Utrecht to CERN in Geneva and Geert asked Ted to keep an eye on his little sister, Loes Fast, who was studying veterinary medicine in Utrecht. Ted quickly developed strong feelings for Loes and in 1965 they got married.
In 1965, he became the first PhD student of Aloysio Janner at the Catholic University Nijmegen and started on the work that resulted in his PhD thesis, Crystallographic Groups in Space and Time, in 1968, thereby already providing the theoretical basis of what would become the superspace approach.
Career
After his promotion Ted Janssen got a position in Nijmegen at the department of Theoretical Solid State Physics. He immediately was given teaching responsibilities. In the years that followed Ted taught many classes, including electrodynamics, classical mechanics, quantum mechanics, complex functions, crystallographic groups, group theory for physicists, chaos theory, soft modes and solid state physics.
Ted was always interested in international collaboration and taught ‘crystallographic groups’ for 6 months in Leuven in 1969. In 1971 Ted accepted an invite from professor Baltensberger to come to the ETH in Zürich for one year. Baltensberger organized weekly meetings between theoretical and experimental physicists. Ted ever since made it a habit to bring theoretical and experimental physicists together on a regular basis.
Back in Nijmegen Ted was promoted to associate professor in 1972 and he continued working with Aloysio Janner and Li Ching Chen on space-time symmetry of electromagnetic fields and independently on PUA (projective unitary/anti-unitary) representations. In 1972 Aloysio and Ted also started their long collaboration with Pim de Wolff. Together with Aloysio Janner and Pim de Wolff he was one of the founders of the higher dimensional superspace approach in crystal structure analysis for the description of quasiperiodic crystals and modulated structures. This collaboration and its results received international recognition in 1998 with the Aminoff Prize from the Swedish Academy of Science. The award ceremony was followed by a symposium and the speakers were Aloysio Janner, Ted Janssen, Gervais Chapuis, Mike Glazer, Borje Johansson, Sander van Smaalen, Vaclav Petrcek and Reine Wallenberg.
In 1973 and 1975 Ted and Aloysio organized conferences on ‘Group Theoretical Methods in Physics’ in Nijmegen. These are small conferences that attract both mathematicians and physicists. The series still exists. In 1993 Ted was appointed as professor at Utrecht University and in 1994 he took Aloysio’s position in Nijmegen after Aloysio retired. Also in 1994 Ted organized the conference Dyproso 1994 (Dynamic Properties of Solids) in Lunteren.
In 1987 Ted joined the board of EMF (European Meeting on Ferro- electricity) and a few years later also the IMF (International Meeting on Ferroelectricity). Ted organized EMF-8 in 1995, in Nijmegen. In 1997 he joined the board of Aperiodic (Modulated Structures, Polytypes and Quasicrystals) and he organized Aperiodic-2000, again in Nijmegen. Ted also was a board member of ICQ, NVK (Nederlandse Vereniging voor Kristallografie – Dutch Union of Crystallography), LOTN (Collaboration of Dutch Institutes for Theoretical Physics), and the Dutch organization of Fundamental Research in Solid State Physics.
Ted attended many conferences and was often traveling. In the earlier years his wife Loes worked as a veterinarian and took care of the children, but once all children had left the house Loes would join Ted on many of his travels. Ted spent time as visiting lector or professor in Leuven (1969), Zürich (1971-1972), Dijon (1987), Paris, Orsay, Palaiseau (1992), Gif-sur-Yvette (1993), Grenoble (1986 and 1990), Marseille (2001), Nagoya (1992), Lausanne (2003), Beer Sheva (2003) en Sendai (2004-2005 and 2013).
In 2014 Aloyiso and Ted received a second award, the Ewald Prize, one of the most prestigious prizes in crystallography, of the International Union of Crystallography during the IUCr conference in Montreal.
Death
Ted Janssen died in Groesbeek, Netherlands, on September 29, 2017, after a short and devastating struggle with leukemia. He did however work until the last day, finishing his edits for the second edition of the book "Aperiodic structures: from modulated structures to quasicrystals" that was published in 2018.
Selected bibliography
Books
Papers
References
1936 births
Theoretical physicists
2017 deaths
20th-century Dutch physicists
Crystallographers
Mathematical chemistry
Academic staff of Radboud University Nijmegen
Utrecht University alumni
Radboud University Nijmegen alumni | Ted Janssen | [
"Physics",
"Chemistry",
"Materials_science",
"Mathematics"
] | 1,701 | [
"Drug discovery",
"Applied mathematics",
"Theoretical physics",
"Theoretical chemistry",
"Crystallography",
"Mathematical chemistry",
"Molecular modelling",
"Crystallographers",
"Theoretical physicists"
] |
67,698,768 | https://en.wikipedia.org/wiki/Ambrogio%20Fasoli | Ambrogio Fasoli (born 10 November 1964 in Milan) is a researcher and professor working in the field of fusion and plasma physics. Since January 2025, he is Vice President for Academic Affairs at École Polytechnique Fédérale de Lausanne (EPFL). He was Associate Vice President for Research at EPFL since 2021.
A Fellow of the American Physical Society, he is Director of the Swiss Plasma Center, located at EPFL.. Since 1 January 2019, he chairs the European consortium EUROfusion, the umbrella organisation for the development of nuclear fusion power in Europe.
From 2014 through 2020, he was also Editor-in-Chief of Nuclear Fusion, the peer-reviewed scientific journal of the International Atomic Energy Agency (IAEA). Fasoli represents Switzerland on the Governing Board of Fusion For Energy, the agency that manages Europe's contributions to the international fusion reactor project ITER.
Career
Fasoli graduated from the University of Milan, (in physics, 1988) and from EPFL, the Swiss Federal Institute of Technology in Lausanne (PhD in Science, 1993, EPFL best thesis award). He went on to do his post-doctoral research on JET, the world's largest fusion reactor, participating in 1997 in the experiments that still hold the record for fusion power generated for peaceful purposes by a plasma on earth.
He joined the Physics Department of the Massachusetts Institute of Technology (MIT) as tenure track assistant professor in 1997. At MIT, he led the plasma physics research group and coordinated the international scientific collaboration between MIT and JET.
In 2001, he joined the EPFL Faculty of Basic Sciences, then became associate professor, before being appointed full professor in physics in 2008. In 2007, he was appointed executive director of the Centre de Recherches en Physique des Plasmas (CRPP), of which he became director in 2013, and which became the Swiss Plasma Center in 2015 Fasoli was responsible for several years for EPFL's TCV Tokamak, one of the national facilities in Europe participating in the research for the international reactor ITER
In 2008, Fasoli was elected as a Fellow of the American Physical Society. Since 2001, he has been a visiting professor in the Department of Physics at MIT
From 2010 through 2014, he was the Head of Physics Strategic Committee, and a member of the Directorate of the EPFL Basic Science Faculty. Since 1 January 2019, he is the chair of the European consortium EUROfusion, the umbrella organization of Europe's fusion laboratories.
He has developed a Massive open online course (MOOC) dedicated to fusion and plasma physics, with several thousand registrations each year.
Scientific contributions
Fasoli works in the areas of basic plasma physics, burning plasma physics, and tokamak physics. At the Swiss Plasma Center, located at EPFL (the Swiss Federal Institute of Technology in Lausanne), he has founded and led the basic plasmas research group, and built the TORPEX facility. He was responsible for the TCV tokamak, the experimental fusion reactor, for several years.
plasma physics and nuclear fusion.
At MIT, (1997-2001), he founded and led the plasma physics research group, constructing the Versatile Toroidal Facility (VTF) experiment to study the physics of magnetic reconnection, and coordinated the international scientific collaboration between MIT and JET.
As a researcher at JET, he initiated a series of experiments on the interaction between plasma particles and Alfvén waves, of interest to fusion reactor plasmas. He participated in 1997 in the experiments that still hold the record for fusion power generated for peaceful purposes by a plasma on earth
Selected works
Awards and honours
Polysphère, EPFL (the Swiss Federal Institute of Technology) best teacher's award (2008 and 2014)
Fellow of American Physical Society (2008)
Marie Curie Fellowship, as host of Dr. P.Ricci (2006)
Marie Curie Fellowship, as host of Dr. M.McGrath (2002)
Swiss National Science Foundation Professeur Boursier (2001)
US Department of Energy - Plasma Physics Junior Faculty Award (2000)
MIT Charles Reed Faculty Award (1999)
EPFL best thesis Award (1993)
References
External links
Ambrogio Fasoli on EPFL's (École Polytechnique Fédérale de Lausanne) website
Website of the Swiss Plasma Center
21st-century Italian physicists
École Polytechnique Fédérale de Lausanne alumni
Fellows of the American Physical Society
Living people
20th-century Italian physicists
Academic staff of the École Polytechnique Fédérale de Lausanne
Academic journal editors
University of Milan alumni
Italian expatriates in Switzerland
Scientists from Milan
1964 births
Plasma physicists | Ambrogio Fasoli | [
"Physics"
] | 937 | [
"Plasma physicists",
"Plasma physics"
] |
67,698,812 | https://en.wikipedia.org/wiki/Turkic%20creation%20myth | The Turkic creation myth is an ancient story about the creation of the Gaoche (Chinese: 高車 / 高车, Pinyin: Gāochē, Wade-Giles: Kao-ch'e) (aka Tiele people) told among various Turkic peoples.
The story
The tale is told in Chinese in the Book of Wei and the History of the Northern Dynasties
Notes
See also
Grey wolf (mythology)
Turkic mythology
Turkic mythology
Creation myths | Turkic creation myth | [
"Astronomy"
] | 88 | [
"Cosmogony",
"Creation myths"
] |
67,699,403 | https://en.wikipedia.org/wiki/Enteral%20respiration | Enteral respiration, also referred to as cloacal respiration or intestinal respiration, is a form of respiration in which gas exchange occurs across the epithelia of the enteral system, usually in the caudal cavity (cloaca). This is used in various species as an alternative respiration mechanism in hypoxic environments as a means to supplement blood oxygen.
Turtles
Some turtles, especially those specialized in diving, are highly reliant on cloacal respiration during dives. They accomplish this by having a pair of accessory air bladders connected to the cloaca which can absorb oxygen from the water.
Other animals
Various fish, as well as polychaete worms and even crabs, are specialized to take advantage of the constant flow of water through the cloacal respiratory tree of sea cucumbers while simultaneously gaining the protection of living within the sea cucumber itself. At night, many of these species emerge from the anus of the sea cucumber in search of food.
The pond loach is able to respond to the periodic drying in their native habitats by burrowing into the mud and exchanging gas through the posterior end of their alimentary canal.
Studies have shown that mammals are capable of performing intestinal respiration to a limited degree in a laboratory setting. Mice were subjected to hypoxic conditions and supplied oxygen through their intestines survived an average of 18 minutes compared to 11 minutes in the control group. In 2024 Ig Nobel Prize an award in physiology has been given to a study proving that pigs are capable of this as well. When the intestinal lining was abraded before oxygen was introduced, most of the animals survived for at least 50 minutes. Investigations are planned regarding the effectiveness of the strategy, the safety of this application of perfluorocarbons, and the feasibility of application to humans. It has potential application to people with a respiratory disease or lung damage.
See also
Cutaneous respiration
References
Respiration
Animal anatomy
Digestive system | Enteral respiration | [
"Biology"
] | 412 | [
"Digestive system",
"Organ systems"
] |
67,699,681 | https://en.wikipedia.org/wiki/Tomatidine | Tomatidine is an anabolic chemical compound that prevents muscle wasting. It is naturally found in leaves of tomatoes and green tomatoes. Chemically, it is the aglycone of tomatine. It has been shown to have multiple health benefits. Tomatidine is an inhibitor of skeletal muscle atrophy, and a potential therapeutic agent for aging-associated sarcopenia, reducing weakness and atrophy in aged skeletal muscle by interaction with the ATF4 (a critical mediator of age-related muscle weakness and atrophy).
Dietary supplementation with ~0.04% tomatidine for 10 weeks reduces plasma cholesterol and atherosclerosis in ApoE-deficient mice without evidence of toxicity.
Research
It is investigated as compound to increase longevity and it increased lifespan and healthspan of C. elegans. It is also investigated in osteoporosis.
See also
Ursolic acid
References
Heterocyclic compounds with 5 rings
Piperidines
Oxygen heterocycles
Spiro compounds | Tomatidine | [
"Chemistry"
] | 213 | [
"Organic compounds",
"Spiro compounds"
] |
67,700,026 | https://en.wikipedia.org/wiki/SPIRE1 | SPIRE1 is a protein that interacts with actin monomers and actin nucleating formin proteins. SPIRE1 was first identified in Drosophila melanogaster. SPIRE1 contains an N-terminal KIND domain which binds formins and four actin-binding WH2 domains which nucleate actin filaments.
References
Proteins | SPIRE1 | [
"Chemistry"
] | 74 | [
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
67,701,648 | https://en.wikipedia.org/wiki/Gibellula%20pulchra | Gibellula pulchra is a species of parasitic fungus found on arachnids. The species Gibellula pulchra is commonly found around the world.
The genus Gibellula was named after Prof. Giuseppe Gibelli. Some researchers have mistaken Gibellula suffulata as Gibellula pulchra though they are different species from the same genus that both prey on arachnids. Specimens of Gibellula pulchra from North America are held in various collections facilities: the Herbarium of the University of Michigan, Herbarium of Cornell University, Mycological Collection of the U.S. Bureau of Plant Industry, Herbarium of the New York Botanical Garden, and Farlow Herbarium.
Habitat
Like other ascomycetes, Gibellula pulchra can be found under stones, bark, leaves, on decaying logs, or in hidden burrows of plant matter on the forest floor. Often Gibellula pulchra is more clearly identified after entering an arachnid, enveloping their host, and growing on their cadavers. Once a spider dies from the Gibellula pulchra pathogenic fungi, G. pulchra produces a large fruiting body out of the cadaver.
Biology
Gibellula is a parasitoid from the Cordycipitaceae family. In order to attach to a host, Gibellula pulchra sends out spores. When an unlucky spider comes in contact with a spore from Gibellula pulchra, the spores germinate on and envelop the spider host. After germinating, Gibellula pulchra penetrates the host body with a yellow coat of mycelium and digests the spider from the inside out, when the spider has died, stiff lavender clavae begin to shoot up out of the spider cadaver. Gibellula pulchra does not digest the exoskeletons of arachnids which is why the shape of the spider is still visible after Gibellula pulchra has enveloped and killed its host. Not long after the spider host dies, the colors of the mycelium and clavae fade to a cream or ashy color.
References
Note sur Gibellula pulchra (Hypocreales), un hyphomycète parasite des araignées
Curtis's botanical magazine
Cordycipitaceae
Parasitic fungi
Fungi described in 1877
Taxa named by Pier Andrea Saccardo
Fungus species | Gibellula pulchra | [
"Biology"
] | 510 | [
"Fungi",
"Fungus species"
] |
67,703,573 | https://en.wikipedia.org/wiki/Organotechnetium%20chemistry | Organotechnetium chemistry is the science of describing the physical properties, synthesis, and reactions of organotechnetium compounds, which are organometallic compounds containing carbon-to-technetium chemical bonds. The most common organotechnetium compounds are coordination complexes used as radiopharmaceutical imaging agents.
In general, organotechnetium compounds are not typically used in chemical reactions or catalysis due to their radioactivity. Research on technetium chemistry is often done in conjunction with rhenium as a isoelectronic non-radioactive alternative to technetium.
Brief history
Technetium were first used as a radiopharmaceutical in 1961. Of the radiopharmaceuticals in clinical use for SPECT (single photon emission computed tomography), a majority of the compounds are 99mTc complexes. Three generations of technetium radiopharmaceuticals currently exist and are used. The first generation do not localize specifically and are considered perfusion agents. Second generation has a peptide based targeting portion. The third generation of technetium radiopharmaceuticals features organotechnetium compounds that can localize in the body in a biomimetic manner.
Examples
A vast majority of technetium compounds used in radiopharmaceutical imaging and diagnosis are inorganic coordination complexes. There are a number of “classical” organometallic organotechnetium compounds, specifically containing carbon-technetium bonds are in clinical use. These organotechnetium compounds are mostly seen as technetium tri-carbonyl compounds and technetium cyclopentadienyl compounds.
One of the most prominent radio pharmaceutical compounds in clinical use is Cardiolie®, also known as 99mTc-Sestamibi. This organotechnetium compound is applied for myocardial imaging. The d6 electron configuration is highly stable due to its low oxidation state. The Tc(I) complex is further stabilized by the high reducing potential of the isonitrile ligands.
The above piano-stool organotechnetium complex is a third generation radiopharmaceutical. The cyclopentadienyl ligand acts as a bio isostere to a phenyl group in the amino acid phenylalanine.
Synthesis
Radioactive 99mTc is obtained in the pertechnetate form in dilute aqueous solution from 99Mo/99mTc generators. Pertechnetate can then be made into more useful carbonyl and hydrate precursors for subsequent synthesis into technetate complexes.
As the starting radiometals are most available in aqueous solution due to method of isolation, the chemistry for synthesis of technetate compounds must be done in aqueous solution.
The study of technetium compounds is typically done in conjugation with rhenium as an isoelectronic and non-radioactive alternative to technetium.
Precursors
For 99mTc and 188Re, the synthesis of compounds start with pertechnetate or perrhenate in saline at low concentration, obtained from 99Mo/99mTc and 188W/188Re generators. The aquo tricarbonyl precursors are useful for accessing Tc and Re complexes. The metals have d6 low-spin electronic configuration, providing high kinetic stability, and highly stable M-C bonds. Consequently, the three CO ligands always remain coordinated, while ligands readily replace the three water molecules. Typical organotechnetium compounds thus feature the tricarbonyl motif.
Typical methods of organometallic compounds synthesis difficult to utilize. To be useful as a radiopharmaceutical, the reaction should be done in an aqueous saline solution that can be injected into the body intravenously.
Double Ligand Transfer
A double ligand transfer (DLT) reaction was developed by Martin Wenzel for synthesis of organotechnetium/organorhenium complexes. The reaction features the synthesis of organotechnetium piano-stool compounds from ferrocene. The reaction was further studied and optimized by Katzenellegbogen. Unfortunately, the utility of this method in the synthesis of radiopharmaceuticals is limited by the use of organic solvent.
Mechanism
This mechanism is proposed to proceed by ring slippage. First, reduction and carbonylation of the pertechnetate/perrhenate with CrCl3 and/or Cr(CO)6 to from the 6 coordinate intermediate. Subsequent reaction with the substituted ferrocene through ring-slipped, bridged intermediates then gives product. The transfer of the more electron deficient ring is favored by the stabilization of the transition state of η5- η3 ring slip of ferrocene.
Metal-Mediated Retro Diels-Alder
Aqueous synthesis enables development for medically relevant radiopharmaceuticals. First aqueous synthesis of fac-[99mTc(η5 -Cp-C(O)CH3)(CO)3] was described by the Alberto lab utilized a metal-mediated retro Diels-Alder to synthesize the organotechnetium complexes.
Mechanism
In a step-wise manner, the carboxylate first coordinates to technetium followed by coordination to the adjacent cyclopentadiene (Path A). The reaction is thermodynamically driven, given a strong electronic interaction between [99mTc(CO)3]+ and the cyclopentadiene.
The favorable formation of the {(η5-Cp)Tc} as a driving force for formation of the product 2, prompted the use of the Diels-Ader dimer (HCp-COOH)2 (Thiele’s acid) as a precursor to the cyclopentadiene. Thermal cracking of 3 typically requires T >160 °C. Reaction of 3 and 1 at 95 °C for 30 min in buffer gave quantitative formation of 2. As no free HCp-COOH was observed, in situ retro Diels-Alder and subsequent entry into path A was excluded.
Examples
The metal-mediated retro Diels-Alder reaction suggests a general approach to [(Cp-R)99mTc(CO)3], enable access to a variety of R groups on the Cp ring.
With the development of this retro Diels-Alder method for synthesis of 99mTc and Re complexes in aqueous media by the Alberto lab, The labeling of biomolecules with piano-stool like complexes is now possible. Enabling access to the development of novel radiopharmaceuticals.
Reactivity
Technetium has been shown to react similarity to osmium. Able to catalyze a cis dihydroxylation.
References
Organometallic compounds | Organotechnetium chemistry | [
"Chemistry"
] | 1,410 | [
"Organic compounds",
"Organometallic compounds",
"Organometallic chemistry",
"Inorganic compounds"
] |
67,704,475 | https://en.wikipedia.org/wiki/Richard%20A.%20Andersen%20%28chemist%29 | Richard "Dick" A. Andersen (November 16, 1942 – June 16, 2019) was a professor of chemistry at the University of California, Berkeley, and faculty senior scientist at the chemical sciences division of Lawrence Berkeley National Laboratory.
Early life and career
Born in Oklahoma in 1942, Richard Allan Andersen was raised and educated in the small town of Yankton, South Dakota. He obtained his bachelor's degree in 1965 from the University of South Dakota. Andersen pursued graduate studies at the University of Wyoming, working under the supervision of Professor Geoffrey Coates. Andersen was Coates' last student. In 1973, Andersen earned his Ph.D. with several fundamental organometallic and alkoxide compounds of beryllium.
Andersen then spent a year as postdoctoral researcher at the Oslo Centre for Industrial Research. On the day it was announced that Geoffrey Wilkinson and Ernst O. Fisher would share the 1973 Nobel Prize in Chemistry, Andersen received an offer to conduct his postdoctoral research in Wilkinson's laboratory at Imperial College London. Andersen took up this post a few months later, in 1974. In June 1976 he joined the faculty at the University of California, Berkeley's department of chemistry. He remained a professor in the department until his death in 2019.
Andersen was also active in teaching throughout his career, and was well-known for teaching from the primary inorganic chemistry literature, as well as his hands-on approach to teaching undergraduate laboratory courses.
Research
Andersen began his independent research career at UC Berkeley in 1976. Initially his research focused on ligand substitution patterns in quadruply-bonded Mo2 complexes. He also studied actinide coordination complexes bearing the sterically bulky amido ligand –N(SiMe3)2, including the uranium(III) compound U[N(SiMe3)2]3, which was later found to have pyramidal geometry.
Awards and honors
Andersen was awarded many Visiting Professorships around the world, including appointments in Sevilla, Lyon, Montpellier, New South Wales, and Zurich. He was also an Alexander von Humboldt Professor in various locations in Germany (1994). Andersen was also a member of the Royal Chemical Society, American Chemical Society, and Sigma Xi.
References
1942 births
2019 deaths
American chemists
Academics from Oklahoma
Inorganic chemists
20th-century American chemists
21st-century American chemists
UC Berkeley College of Chemistry faculty
Chemists from Oklahoma
Chemists from South Dakota | Richard A. Andersen (chemist) | [
"Chemistry"
] | 482 | [
"Inorganic chemists"
] |
67,705,338 | https://en.wikipedia.org/wiki/Karsten%20Meyer%20%28chemist%29 | Karsten Meyer (born May 17, 1968, in Herne, Germany) is a German inorganic chemist and Chair of Inorganic and General Chemistry at the Friedrich-Alexander University of Erlangen-Nürnberg (FAU). His research involves the coordination chemistry of transition metals as well as uranium coordination chemistry, small molecule activation with these coordination complexes, and the synthesis of new chelating ligands. He is the 2017 recipient of the Elhuyar-Goldschmidt Award of the Spanish Royal Society of Chemistry, the Ludwig-Mond Award of the Royal Society of Chemistry, and the L.A. Chugaev Commemorative Medal of the Russian Academy of Sciences, among other awards. He also serves as an Associate Editor of the journal Organometallics since 2014.
Early life and education
Meyer was born on May 17, 1968, in Herne, Germany. He studied chemistry at the Ruhr University Bochum, receiving his diploma (in chemistry) in May 1995. In summer 1995, Meyer then joined the laboratory of Professor Karl Wieghardt at the Max Planck Institute for Radiation Chemistry, where he worked on the synthesis of novel high-valent nitrido complexes of manganese, chromium and iron. These nitrido complexes were generated by the photolysis of the corresponding azido complexes. Meyer graduated in January 1998 with his Ph.D. He then moved to the Massachusetts Institute of Technology as a DFG Postdoctoral Fellow in 1998 to conduct research in the laboratory of Professor Christopher Cummins. AT MIT, Meyer worked on amido complexes of uranium with novel amido ligands and dinitrogen cleavage with heterobimetallic complexes of niobium and molybdenum.
Independent career
In 2001, Meyer began his independent career as an assistant professor at the University of California, San Diego. Then in 2006, Meyer moved to the University of Erlangen-Nürnberg as the Chair of the Institute of Inorganic & General Chemistry.
Research
Meyer's early work featured explored the coordination chemistry of uranium with small molecules such as carbon dioxide and light alkanes. Additionally, Meyer's group synthesized novel tripodal N-heterocyclic carbene ligands to stabilize reactive intermediates such as an iron(IV) nitride. In 2011, in collaboration with Prof. Jeremy M. Smith's group, Meyer achieved the first synthesis and characterization of a stable iron(V) nitride complex.
Other research highlights include:
2013: In collaboration with Prof. Ingo Krossing's group, the first crystallographic characterization of the 2-norbornyl cation, a prototypical non-classical carbocation whose exact structure has been debated for decades
2014: The synthesis of a novel tripodal redox-active ligand class, which was then used to stabilize a low-valent U(II) oxidation state complex
2016: The first example of a uranium-based electrocatalyst for the reduction of water to dihydrogen, and the investigation of its reaction mechanism
Awards
Hellman Fellow, Chris & Warren Hellman Young Faculty Award, 2002
Faculty Career Development Award, Academic Senate, UCSD, 2003
Alfred P. Sloan Research Fellowship, 2004
Lifetime Honorary Member, Israel Chemical Society, 2009
Visiting Professor at the University of Manchester, since 2009
Japan Society for the Promotion of Science (JSPS) Award, 2009
Dalton Transactions European / African Lectureship Award, 2010
Fellow of the Royal Society of Chemistry, 2011
JSPS Professorship, "Brain Circulation Project", Nagoya Institute of Technology, 2015
Elhuyar-Goldschmidt Award, Spanish Royal Society of Chemistry, 2017
Ludwig Mond Award, Royal Society of Chemistry, 2017
L.A. Chugaev Commemorative Medal, Russian Academy of Sciences, 2017
Professional memberships
German Chemical Society (GDCh), since 1995
American Chemical Society (ACS), since 1997
Royal Society of Chemistry (RSC), since 2011
Personal life
Meyer's hobbies include nature and macro photography, scuba diving, and driving his car on a closed circuit.
References
21st-century German chemists
1968 births
Living people
Inorganic chemists
University of San Diego faculty | Karsten Meyer (chemist) | [
"Chemistry"
] | 851 | [
"Inorganic chemists"
] |
67,705,760 | https://en.wikipedia.org/wiki/Mass%20Effect%203%20ending%20controversy | Mass Effect 3 is an action role-playing video game and the third installment of the Mass Effect video game series, developed by BioWare and published by Electronic Arts (EA), the first in the series to not be published by Microsoft Game Studios (MGS). Upon its release March 6, 2012, for the PlayStation 3, Xbox 360, and Windows, Mass Effect 3 generated controversy when its ending was poorly received by players who felt that it did not meet their expectations. Criticisms included the ending rendering character choices inconsequential, a general lack of closure, plot holes, and narrative inconsistency.
On June 26, 2012, developers released an Extended Cut as downloadable content (DLC) intended to clarify the endings and remedy fan concerns. The initial announcement of the development of add-on content to amend the ending as well as the subsequent release of Extended Cut sparked debates over the treatment of video games as art and whether BioWare should have to alter their vision of the work in response to external pressure, regardless of its quality.
Background
In the original Mass Effect trilogy, players assume the role of Commander Shepard, a customizable avatar who leads allies from across the Milky Way galaxy in a struggle against a collective of powerful synthetic lifeforms called the Reapers, who harvest the galaxy of sentient spacefaring life every 50,000 years. By the events of Mass Effect 3, the Reapers have arrived in the galaxy and begin harvesting entire worlds. To stop them, Shepard must form an alliance between all of Mass Effects alien races to build the Crucible, a megastructure built from blueprints designed by the civilizations from previous cycles, including the Protheans, which can theoretically destroy the Reapers.
As Shepard, players dispatch a final "Marauder" enemy, entering a Reaper teleportation beam on Earth to reach the Citadel alongside their close ally and mentor, David Anderson, and begin the game's ending sequence. This follows a long and grueling battle in London where Shepard is gravely wounded by Harbinger, the leader of the Reapers. Once there, Shepard and Anderson engage in a dialog-based final showdown with the Illusive Man, the leader of Cerberus; only Shepard survives the confrontation. Shepard then attempts to fire the Crucible, only to be transported to the Citadel's pinnacle. They encounter the Star Child, the Reaper gestalt intelligence as manifested by the Catalyst in the form of a child. The AI explains the Reapers' true motives - the repeated culling prevents organic life from inevitably being rendered extinct by their own less-advanced artificially intelligent creations.
Having conceded defeat to Shepard, it presents up to three options for activating the Crucible, which will break the Reapers' galactic cycle of extinction:
Destroy the Reapers and all other synthetic life, including allies such as EDI and the geth.
Control the Reapers by copying Shepard's influence into a new artificial intelligence, creating a galactic peacekeeping force.
Merge all organic and synthetic life via synthesis, resulting in both life forms achieving a perfect understanding.
By making any of the above choices, Shepard activates the Crucible, which emits a wave of energy that spreads throughout the galaxy via the mass relays, damaging them in the process in the case of the destroy option. As the Normandy is hit by the wave of energy, it crashes on a remote planet.
Development
Chris Hepler, one of the game's writers and the project's de facto "loremaster", explained in a 2021 interview that the final ending decision was both easier and had "much more project momentum", and that it was embraced by the project leads almost immediately, including its use of "space magic". The controversial aspects about the endings, such as Destroy ignoring the AI problem the Reapers aimed to prevent, Control rewarding the Reapers, and Synthesis violating the galaxy's bodily autonomy, were intentional in order to not make any of the choices perfectly moral or "right" for everyone. However, he also agreed that the game hinted at alternate endings that could have been used, and that a more hard science-based ending had been considered. Concept scenarios for alternate endings that were discarded included:
Dark energy
The developers attempted to write a viable ending around the concept of dark energy and had considered a number of hypothetical theories surrounding it as the reason behind the creation of the Reapers: examples that were proposed by team members included curbing the use of dark energy by organic civilizations due to its cumulative entropic effect that would hasten the end of the universe, or preventing the universe's inevitable descent into a Big Crunch by focusing on organic species with biotic potential. The game was acknowledged to contain direct hints that the Citadel species and the Reapers would team up to stop a dark energy anomaly that threatened the universe with destruction, although this was not seriously discussed by the writers.
Cyclical ending
This ending scenario, shared by series concept artist Matt Rhodes on his personal website, envisions a villainous Shepard being confronted by either Ashley Williams or Kaidan Alenko, the survivor of the Virmire incident from the first game, after being willingly modified by Reaper technology. This is intended to echo the character arc and downfall of Saren Arterius in the first Mass Effect as a "cyclical twist".
Illusive Man boss fight
An endgame scenario which never progressed past the concept art stage would have the Illusive Man transform into a Reaper creature, not unlike Saren at the end of the first game, for a final boss fight.
Detonating mass relays as a trap for the Reapers
Former Mass Effect lead writer Drew Karpyshyn revealed in a July 2022 interview that a proposed ending which was under serious consideration by the team would involve the Reapers being lured through the mass relays, and the entire network is then detonated to wipe them out. Since every galactic community is isolated from each other as a result of the damaged relays, it would serve as the premise for a direct sequel which would have been the fourth main series installment.
Strong nuclear force ending
Hepler's preferred ending eschewed "space magic" entirely and involved the Crucible being a weapon that annihilated objects with a high atomic number, including the Reapers, their creations, such as the Husks (which were implied to be created with niobium cybernetics) and Commander Shepard themselves, an idea inspired by Probability Moon by Nancy Kress. However, the final ending was approved too quickly for Hepler to pitch his idea, and he was afraid of being sued for copying the idea without permission.
Reaper Queen
Shepard would discover a Reaper "Queen" that had been trapped somewhere within the Citadel and would then be prompted with three choices on how to deal with her. The choices offered by this discarded scenario ended up being similar in nature to the choices offered by the Catalyst in the final game's ending.
Response
Although Mass Effect 3 launched in early March 2012 to a predominantly positive critical reception, its endings received a very poor reception from players. By mid-March 2012, a contingent of displeased fans had organized an internet campaign called "Retake Mass Effect" to demand a better ending to the game, part of which included a charity drive for the organization Child's Play. The drive raised $80,000 in less than two weeks before it was stopped. One fan made a complaint to the Federal Trade Commission, arguing that BioWare did not deliver on the promise of its game. Marjorie Stephens, Better Business Bureau director of marketplace services, alleged that the game falsely advertised the ability to completely shape the outcome. However, in June 2012, the UK Advertising Standards Authority ruled that, while disappointing, the endings were different enough to not be misleading to an actionable extent.
Opinions over the game's endings divided many critics. Among the criticisms include the ending rendering character choices inconsequential; a general lack of closure; lore contradictions and plot holes; character and narrative inconsistencies; the absence of a final boss battle; and inconsistencies between statements by BioWare staff during the game's development and the form the endings ultimately took. Commentators took note of the magnitude and scale of the public reaction and highlighted how invested the series had made its players. A widely discussed fan theory proposed that the endings were a hallucinated consequence of Shepard's gradual, forcible Reaper indoctrination over the course of the trilogy, also positing that the "Destroy" ending was purposely colored red to dissuade Shepard from picking it, and thus, overcoming the mind control. Dissatisfied fans also turned the final enemy unit encountered in combat into a sarcastic Internet meme called Marauder Shields.
A number of individuals associated with Mass Effect 3, such as project director Casey Hudson and cast member Jessica Chobot, initially spoke out in support of the ending shortly after the game's launch. By March 16, 2012, Hudson and community coordinator Chris Priestly had acknowledged the growing controversy and provided assurances that the team were listening to feedback. Hudson later went on record and conceded that players ought to have more closure and answers for the creative direction they had taken. BioWare co-founder Ray Muzyka later announced that the company planned to address the criticism, with a further announcement to be made in April 2012. Chobot issued a public apology on a blog post dated April 2, 2012 following backlash from some players in response to her choice of tone and words.
BioWare announced a free downloadable content pack on April 5, 2012, that would expand upon the ending. Some commentators expressed concerns that changing the endings by giving into fan demand would compromise the developers' creative vision as well as the artistic integrity of their work, and ultimately sets a bad precedent for the development of creative works in the video game industry. Video game developer Ken Levine remarked that he felt sad that players were fervently calling for a revised Mass Effect 3 ending as they would be left “disappointed”. Others like Stephen Totilo from Kotaku welcomed BioWare's decision to be open towards revising the ending to their work.
The expansion, Extended Cut, was released for most platforms on June 26, 2012. While not drastically changing the existing endings, it retconned various plot holes noted by fans, such as the complete destruction of the Mass Relays, and more thoroughly explained the Star Child's logic. Each ending was supplemented with additional cutscenes during the ending sequence, and a montage-based epilogue that depicts the aftermath of Shepard's actions, such as the fates of various supporting characters, alien species and entire worlds, all of which are variable based on prior narrative choices made by players along with their accumulated "Effective Military Strength" (EMS) score. Extended Cut also provides an additional choice for players to refuse the offer and have Shepard attack the Catalyst, which results in the Crucible not being activated and an inevitable Reaper victory over the current cycle of organics. Following the release of the Extended Cut pack, Mike Fahey from Kotaku observed that fan reaction was generally mixed, although certain individuals like the FTC complainant expressed satisfaction with the reworked ending sequences it introduced. Video game publications were similarly divided, with some critics such as Joe Juba of Game Informer describing the new additions as a "substantial improvement" over the original ending, while others such as Paul Tassi of Forbes felt it was "too little, far too late."
Indoctrination theory
A notable and widely circulated, though now allegedly discredited, fan theory about the ending was that Shepard had undergone gradual "indoctrination", or brainwashing, over the course of the series, and their mind had been fully infiltrated by the Reapers. The theory was created by dissatisfied fans by piecing together apparent evidence throughout the game, starting when Shepard touched the Prothean Beacon on Eden Prime, an event that caused them to have visions. After being hit by Harbinger's beam, Shepard hallucinates the ending, which metaphorically represents whether they can resist the brainwashing. In the theory, only "Destroy" would free Shepard from the mind control and allow them to awaken.
Hepler clarified that the theory was based on a coincidence, saying "we didn't write that" and that it was never discussed in staff meetings as a plot point. While he agreed the ending was "trippy", it was entirely due to Shepard being on the verge of death. However, he expressed approval at the theory, calling it "interesting" and supporting the idea of mods or fanfiction based on the topic.
Aftermath
Retrospective discussions of Mass Effect 3 inevitably involve attention towards its ending. James Davenport of PC Gamer opined that the game's ending received an "inordinate" amount of criticism, which distracts players from the other positive or exemplary aspects of Mass Effect 3. Forbes contributor Erik Kain took the view that the public outcry and the subsequent response from BioWare and EA "may end up being a healthy one for the industry, opening a new chapter in gamer/developer/publisher relations", and called the release Extended Edition as a complementary expansion to the original endings a "remarkable" choice that made gamers realize "that they are entitled, and that it isn't a bad thing, to quality games". In 2018, Lucy O'Brien from IGN concurred and remarked that fan-driven internet campaigns like "Retake Mass Effect" have contributed to a paradigm shift in how consumers influence video game developers. With the inclusion of Mass Effect 3 and its DLC content into the Mass Effect Legendary Edition compilation released in 2021, BioWare staff are hopeful that following the passage of time and the release of Legendary Edition, players would reassess their opinion about the ending as the culmination of the trilogy's overarching story arc.
In the absence of significant official changes to the ending, fans released various mods to change the ending into a more satisfying one. One such mod, Priority: Earth Overhaul, makes wide-ranging changes to the main game and its final mission, such as adding new cutscenes and letting the player fight alongside the geth. Another, the Happy Ending Mod by Audemus, removes controversial aspects of the ending such as the Star Child sequence and destruction of the Mass Relays, adding the Star Child's exposition to the Codex. "Destroy" is made the sole ending, but its drawbacks, such as all AI being destroyed and Shepard's possible death, are removed. Having been released for the original game, it was also released for Legendary Edition in 2022. The mod also compatible with Citadel Epilogue Mod, which repurpose the Citadel DLC as an epilogue set a year after Mass Effect 3.
The backlash to Mass Effect 3's ending was suggested as having a significant impact on EA being named Consumerist's 2012 and 2013 Worst Company in America.
See also
Criticism of Electronic Arts
References
Further reading
External links
Revisiting Mass Effect's Many Controversies by GameSpot.
BioWare
Electronic Arts
Mass Effect 3
Criticisms of software and websites
Mass Effect
Video game controversies
Endings | Mass Effect 3 ending controversy | [
"Physics",
"Technology"
] | 3,082 | [
"Physical quantities",
"Time",
"Spacetime",
"Criticisms of software and websites",
"Endings"
] |
67,706,874 | https://en.wikipedia.org/wiki/Ring%20shedding | Ring shedding is a phenomenon in ocean currents where circle or ring-shaped eddies separate from the current. The rings are independent water current systems that can persist for several months and occur in most ocean basins. The separated rings can have both warm or cold cores and play a role in the thermohaline circulation, interocean mixing, and nutrient supply for algae and bacteria. The physical processes behind ring shedding are not fully understood yet and are thus an active subject of research.
Process of ring shedding
Ring shedding often takes place in the retroflection region, the region where the current loops back, as the retroflection is a condition for ring shedding to take place. The turbulent and dynamic nature of the ocean causes the current loop to sometimes close onto itself and separate ("shed") from the current. This results in an independent ring current that drifts away from the main current. The exact moment a ring is shed from the current is often unclear and the process behind it is still an active subject of research. The topography of the ocean floor and incoming eddies from upstream regions could play a role in ring shedding. Other research indicates that ring shedding is driven by barotropic instabilities. When the retroflection region destabilizes, the loop can separate from the current, forming a ring.
Characteristics and observation
The process of ring shedding was first described by Fuglisteri in 1972, who observed rings in the Gulf Stream. Since then, ring shedding has been observed in most ocean basins. Typically, the rings have a diameter of , a depth of up to , and a temperature anomaly of a few degrees Celsius. The rings drift slowly ( per day) until they either decay or are reabsorbed by their parent current.
There are two main types of rings: cold core rings and warm core rings. The warm cores rings are easy to observe: due to their temperature anomaly satellites can detect them with infrared images. Due to geostrophy (and to a lesser extent the expansion of the warmer water), these warm core rings have a higher local sea surface height and can hence also be observed by buoys or satellites using radar altimeters to map the topography of the ocean.
Cold core rings are more difficult to observe as their initial colder surface is warmed by solar radiation. However, under the surface the colder water temperatures persist longer and deeper, allowing measurement and observation using vertical ocean profiles of temperature and salinity.
Occurrence
Kuroshio
The Kuroshio current is a western boundary current in the Northeast Pacific Ocean. In 1994, ring shedding was first observed where the Kuroshio current loops into the South China Sea. The observed current ring was a warm core, anticyclonic ring with a diameter of about and detached from the Kuroshio in the Luzon Strait. The ring had a current speed of about near the surface. The ring had positive temperature anomalies up until a depth of .
Gulf Stream
In the Gulf Stream ring shedding takes place at two locations: in the Gulf of Mexico and along the eastern coast of the United States. The Loop current, as its name suggests, loops into the Gulf of Mexico. At the point of retroflection, ring shedding results in both warm core anticyclonic and cold core cyclonic rings. These rings can have diameters up to and reach depths of . The frequency of the ring shedding in the Loop current has a high interannual variability. However, a shift in the regime of ring shedding has been observed. During the period 1980–1999, there were on average 18 rings shed in the Gulf of Mexico per year, whereas the average between 2000 and 2017 was 33 rings per year. The underlying geophysical reason for this shift in regime around 2000 is still a topic of debate.
Further down the Gulf Stream, along the eastern coast of the United States, ring shedding also takes place, albeit much less frequently. Here only warm core, anticyclonic rings with a diameter of typically are formed. These rings only occur once or twice a year and most of them drift slowly westwards until they are reabsorbed by the Gulf Stream after several months.
Agulhas current
The Agulhas current flows alongside the coast of southeast Africa until it retroflects at the tip of South Africa. Ring shedding occurs in this retroflection region. The rings are warm core and anticyclonic, with a frequency of 4-6 rings per year. However, the shedding of rings happens very irregularly and long periods of almost half a year without any rings occur. The Agulhas rings transport warm and salty water to the Southern Atlantic Ocean. The water from the Agulhas rings can be up to warmer than the water in the Southern Atlantic. The rings from the Agulhas current transport about 15 Sverdrup to the Atlantic Ocean, thereby playing an important role in thermohaline circulation. The exact cause of ring shedding in the Agulhas retroflection region is still unclear. One possible cause is incoming eddies from upstream regions. A second proposed explanation is that the ring shedding is caused by barotropic instabilities in the Agulhas retroflection region.
Effects
Thermohaline circulation
Ring shedding might play an important role in the thermohaline circulation, depending on the location. The movement of the Agulhas rings are paired with leakage of warm and saline Indian Ocean water in the Southern Atlantic Ocean. These rings move in the northwest direction in the Atlantic Ocean and are important for the renewal of North Atlantic Deep Water.
Iron supply
Cold core rings in the Gulf Stream have higher iron concentrations than the subtropical water in other regions of the Northern Atlantic Ocean. Hence, the rings transport iron-rich water from the continental slope to other parts of the Northern Atlantic Ocean. For cyanobacteria, this incoming flux of iron is very important, as they require high iron concentrations to live in these parts of the Atlantic Ocean.
References
Oceanography | Ring shedding | [
"Physics",
"Environmental_science"
] | 1,240 | [
"Oceanography",
"Hydrology",
"Applied and interdisciplinary physics"
] |
67,707,736 | https://en.wikipedia.org/wiki/INSAT-2A | INSAT 2A was the first Indian multipurpose satellite. It was built in India and it came into operation in August 1992. The mission of the satellite was meteorology, Satellite based search and rescue, and Multipurpose Communication such as telecommunication, broadcasting of television and for disaster warning. The satellite weighed 1906 kg containing the fuel propellant. The weight of the satellite was 916 when there was no fuel.
It is situated in the geostationary satellite at a longitude of 74 degree East. Its payload comprises a Radiometer of very high resolution for observing meteorological changes. This radiometer has a resolution of 2 km in the visible band and resolution of 8 km in the infra-red band. The satellite completed its mission on 30 May 2002, and is not in service since 2002. The mission life of the satellite was of 7 years. It was launched from French Guiana using the Ariane 4 as the Launch vehicle.
In comparison to INSAT 1, this satellite can communicate in a better way, both in terms of quality as well as quantity. INSAT 2A has an advanced power amplifiers for catering communication terminals and was the first second generation satellite to replace the INSAT 1. This satellite will also enable the Indian National Satellite system to cover telecommunication circuits at larger distances.
References
Satellites of India | INSAT-2A | [
"Astronomy"
] | 262 | [
"Astronomy stubs",
"Spacecraft stubs"
] |
67,709,864 | https://en.wikipedia.org/wiki/World%20Agriculture%20Prize | The World Agriculture Prize has been awarded annually since 2013 by the Global Confederation of Higher Education Associations for the Agricultural and Life Sciences (GCHERA). The Prize recognizes academics in agriculture and life sciences who have demonstrated career-spanning dedication to research, education, innovation and outreach. These contributions are measured within each recipient's institution geographical scope and as a result these impacts need not be global in scope. 2020 Laurates were awarded $100,000 each.
Laureates
References
Agriculture awards
Academic awards | World Agriculture Prize | [
"Technology"
] | 100 | [
"Science and technology awards",
"Agriculture awards"
] |
67,710,149 | https://en.wikipedia.org/wiki/Cannabielsoin | Cannabielsoin (CBE) is a metabolite of cannabidiol, one of the major chemical components of cannabis.
History
Cannabielsoin in scientific journals was first cited in 1973. It was concluded that cannabielsoin was formed from cannabidiol as part of the metabolic process and is non-psychoactive.
See also
Cannabicitran
Cannabicyclol
Cannabimovone
Cannabitriol
Iso-THC
References
Cannabis
Dibenzofurans
Isopropenyl compounds
Hydroxyarenes
Tertiary alcohols
Human drug metabolites
Phytocannabinoids | Cannabielsoin | [
"Chemistry"
] | 132 | [
"Isopropenyl compounds",
"Chemicals in medicine",
"Functional groups",
"Human drug metabolites"
] |
67,710,549 | https://en.wikipedia.org/wiki/Junwang%20Tang | Junwang Tang, MAE, FRSC and FIMMM, is the Founding Director of Industrial Catalysis Center, and Carbon Neutrality Chair Professor of Materials Chemistry and Catalysis at the Department of Chemical Engineering, Tsinghua University and Visiting Professor at University College London (UCL). He also served as the Director of the University Material Hub at UCL (2016–2019).
Education
Tang was educated at Northeastern University (China), where he received his BSc degree in chemistry in 1995. Then he attended the Institute of Metal Research in China and was awarded a MSc degree in inorganic materials in 1998. In 2001, Tang was awarded a PhD in physical chemistry with research on heterogeneous catalytic conversion of NO to N2, supervised by Tao Zhang at Dalian Institute of Chemical Physics (DICP), China
Career
In 2002, Tang was awarded a Japan Society for the Promotion of Science (JSPS) search Fellowship and NIMS Researcher, enable to expand his research in photocatalysis in the National Institute for Materials Science (NIMS), Japan. In 2005, he was appointed as a senior research associate in the Department of Chemistry at Imperial College London, UK.
In 2009, Tang was appointed as a lecturer in energy (permanent position) in Department of Chemical Engineering at University College London, then promoted to a senior lecturer in 2011, a readership in 2014 and finally a full professor of materials chemistry and engineering in 2017. During this period, he was also appointed as the director of University Materials Hub. In 2022, Tang moved from UCL to Tsinghua University.
Tang is a member of the Academy of Europe / Academia Europaea, a Royal Society Leverhulme Trust Senior Research Fellow, a Fellow of European Academy of Sciences, a Fellow of Royal Society of Chemistry. He also sits on the editorial board of four international journals, e.g. editor of Applied Catalysis B : Environmental, editor-in-chief of Journal of Advanced Chemical Engineering, associate editor of Asia-Pacific Journal of Chemical Engineering and associate editor of Chin Journal of Catalysis, as well as a member of the committees of the RSC Chemical Nanoscience & Nanotechnology. He also sits on the panel of a few counties’ National Science Foundations.
Research
Tang's research interests encompass photocatalytic/thermocatalytic small molecule activation (e.g. CH4, N2, H2O, C6H6 and CO2) and microwave catalysis (e.g. plastic recycling), together with the investigation of the underlying charge dynamics and kinetics by state-of-the-art spectroscopies. According to Google Scholar, these research activities result into >250 journal papers in reputable journals.
Awards and honours
2001: Outstanding President Prize by The Chinese Academy of Sciences.
2003–2005: Japan Society for the Promotion of Science (JSPS) Fellowship by Japan Society for the Promotion of Science.
2008: Young Scientist Award for research on renewable solar energy by The International Association of Catalysis Societies.
2014: Runner-up of the Global Innovator of the Year by IChemE.
2018: IPS Scientist Award in the 22nd International Conference on Chemical Conversion and Storage of Solar Energy.
2019: Winner of the IChemE Global Business Start-Up Award 2019 and Runner-up of the IChemE Global Oil and Gas Award 2019 .
2021: Winder of the IChemE Innovative Product Global Award.
2021: Winner of the 2021 Corday-Morgan Prize from the Royal Society of Chemistry.
2021: Winner of the IChemE Medal Round: The Andrew Medal.
2021 IChemE Innovative Product Award, IChemE
2021 Member of the Academy of Europe
2022 IChemE Global Oil and Gas Award
2022 Fellow of Institute of Materials, Minerals and Mining
References
Photochemists
Chinese expatriates in the United Kingdom
Northeastern University (China) alumni
Academics of University College London
Fellows of the Royal Society of Chemistry
Year of birth missing (living people)
Living people
21st-century chemists
Chinese chemists
21st-century Chinese chemists | Junwang Tang | [
"Chemistry"
] | 827 | [
"Photochemists",
"Physical chemists"
] |
63,379,528 | https://en.wikipedia.org/wiki/Azvudine | Azvudine is an antiviral drug which acts as a reverse transcriptase inhibitor. It was discovered for the treatment of hepatitis C and has since been investigated for use against other viral diseases such as AIDS and COVID-19, for which it was granted conditional approval in China.
Azvudine was first discovered in 2007. It costs 350 Chinese yuan per 7 days for COVID, .
Medical uses
In July 2021, azvudine became conditionally approved in China for the following indication: "to treat high-viral-load cases of HIV-1, in combination with a nucleoside reverse-transcriptase inhibitor and a non-nucleoside reverse-transcriptase inhibitor". The approval text describes it as a dual reverse transcriptase and Vif inhibitor.
In July 2022, azvudine received emergency conditional approval for COVID-19 in adults. It is believed to work by inhibiting the RNA-dependent RNA polymerase (RdRp) enzyme in the SARS-CoV-2 virus.
Adverse effects
According to the manufacturer, phase II trials of azvudine in combination with doravirine and tenofovir disoproxil fumarate in HIV patients found an adverse effect profile similar to, but milder, than lamivudine combined with the two drugs. Very common (> 10%) side effects include dizziness, elevated liver enzymes, vomiting, and elevated alkaline phosphatase. Common (> 1%) side effects include nausea, elevated blood lipids, fever, insomnia, tiredness, and diarrhea. Detailed numbers are provided by Genuine in the slides and the medication package insert. A boxed warning is present at the beginning of the Chinese package insert, describing a risk of "decrease in absolute neutrophil count, increase in total bilirubin, increase in glutathione aminotransferase, and increase in blood glucose".
The small (n=10) open-label pilot study for azvudine used alone in COVID reported no adverse events.
Non-human models
Azvudine is found to be mutagenic in in vitro in the Ames test, CHL test, and in vitro in the mice micronucleus test.
Azvudine is toxic to the reproductive system of rats and rabbit. The mimimum reproductive NOAEL found for males is 5.0 mg/kg/d and for females 0.5 mg/kg/d. It is excreted in rat breast milk; the NOAEL for rat pups is 1.5 mg/kg/d.
Azvudine is mainly toxic to the immune system, bone marrow, and digestive system of model animals. The chronic NOAELs are 0.5 mg/kg/d (rat, 3 months), 0.3 mg/kg/d (rat, 26 weeks), and 0.1 mg/kg/d (beagle dog, 1 month and 39 weeks). For comparison, the chronic human dose for HIV treatment is 0.05 mg/kg/d, using the reference 3 mg dose and an average Chinese body mass of 59.5 kg (2014).
History
Azvudine was first found in literature in a patent filed by Chang Jun-biao of Zhengzhou University. It received its current name in 2009, when researchers at Roche independently discovered it as a Hep C RNA polymerase inhibitor in vitro. In the following years, Chinese scientists tested it in vitro for a number of targets, most importantly HBV (human and duck) and HTLV-1, two viruses with a reverse transcriptase.
It was first proposed as an HIV treatment in 2011, when in vitro tests by the Chang group provided positive results. In 2014, its oral pharmokinetics in rats was elucidated. A phase II study (NCT04109183) was finished in March 2019 by Genuine Biotech. In August 2020, the Chang group found that the substance inhibits vif in vitro. In the same month, China's drug regulator (NMPA) decided to fast-track the approval process, labelling it a first-in-class medication. In July 2021, NMPA granted conditional approval for HIV-1. It was included in the 2021 HIV treatment recommendnation by the Chinese Medical Association and Chinese CDC, published October that year. Curiously, no full results of the trial have been made available for this study in any journal detailing the experiment design . Parts of the results are shown on the drug monograph as well as a 2022 slides deck produced by Genuine for the NHSA available on the latter's website.
Azvudine was found to inhibit some coronaviruses in vitro around 2020, leading to an interest in its use in COVID. An open-label pilot study on mild and moderate cases was performed in 2020, with mildly positive results. A phase III trial was performed in 2022 in China. In July 2022, China's drug regulator granted conditional approval for it to be used to treat COVID-19, following a local phase III trial. Initially, no detailed description of the said trial was published in any journals, but state media quoted some numbers from the developer: "40% clinical improvement in 7 days by FNC group, compared to 11% in control". It is unclear how such "improvement" is defined.
Four phase III clinical trials investigated azvudine's efficacy and safety in adults with mild-to-moderate COVID-19. The findings indicate that azvudine may reduce the time to eliminate detectable levels of virus (viral load) and improve symptoms faster than standard treatment. In trials, it was reported to be safe with few side effects. However, some studies produced inconsistent results in terms of symptom improvement and severe illness prevention. Additionally, the studies tended to use a smaller number of participants than other major COVID-19 drug trials.
Society and culture
Genuine owns two different tradenames for this medication: 双新艾克 (literally "dual new AIDS inhibitor") for HIV use and 捷倍安 (literally "fast extra safe") for COVID use. No generics are available.
Geniune holds one patent related to the drug: the original 2007 patent on the entire class of 2'-fluorine-4'-substituted nucleotides, purchased from Zhengzhou University. Two other Chinese patents on synthesizing the drug are found on Google Patents, but the owners do not appear to be connected to Geniune. Roche held one 2002 patent, CNA028118480A (CN1516590A), over the broader class of 4'-substituted nucleotides. The patent was voided in 2019 after Riboscience, its new holder, stopped paying fees.
References
Further reading
Antiviral drugs
COVID-19 drug development | Azvudine | [
"Chemistry",
"Biology"
] | 1,416 | [
"Antiviral drugs",
"COVID-19 drug development",
"Biocides",
"Drug discovery"
] |
63,380,844 | https://en.wikipedia.org/wiki/Submarine%20signals | Submarine signals had a specific, even proprietary, meaning in the early 20th century. It applied to a navigation aid system developed, patented and produced by the Submarine Signal Company of Boston. The company produced submarine acoustic signals, first bells and receivers then transducers, as aids to navigation. The signals were fixed, associated with lights and other fixed aids, or installed aboard ships enabling warning of fixed hazards or signaling between ships. ATLAS-Werke, at the time Norddeutsche Maschinen und Armaturenfabrik, of Germany also manufactured the equipment under license largely for the European market.
The system used more reliable underwater sound to project acoustic signals from a shore station or an undersea hazard on which a signal was placed. The signals were usually associated with a lightvessel, a bell buoy or hung on a tripod frame on the sea floor connected to a shore stations by cable. At first the system depended on bells operated by electric strikers. Receivers aboard ships could detect the acoustic signal and when equipped with receivers on each side the ship could determine approximate direction from which the signal came. A ship-to-ship system was also produced allowing ships so equipped to detect each other and estimate direction in fog. The company collected data from ships including ranges at which the signals of specific stations were detected. The collected data formed an early base of ocean acoustical properties. The original bells were quickly replaced by the Fessenden oscillator, a transducer, after its invention by Reginald Fessenden with development starting in 1912 at the Submarine Signal Company. That transducer allowed both sending and receiving leading to major advances in both submarine signals and extension into submarine telegraphy and experiments with underwater telephone communication and eventually sonar.
Ships, commercial or naval, equipped with submarine signaling capability had that equipment noted as one of the ship's navigation capabilities in registry information from the first decade of the century until nearly mid century. In 1907 the information was important to insurance underwriters and American Bureau of Shipping required that ships so equipped by indicated by the note "Sub. Sig." in ship's registry information. Commercial lines advertised the capability as a safety measure. Submarine signaling was made obsolescent and overtaken by advances during World War II.
In 1946 the Submarine Signal Company was acquired by and merged with Raytheon, becoming Raytheon's Marine Division, after having become the national leader in underwater sound, sonar and other work with the Navy during the World Wars and branching into other marine systems.
Early research
In 1826 Jean-Daniel Colladon and Jacques Charles François Sturm used a submerged bell for experiments in Lake Geneva. Lucian I. Blake in association with the United States Lighthouse Service did similar work in 1883 using a submerged bell with the explicit purpose of using sound as an aid to navigation. Experiments in England and the United States occurred independently afterward.
Reception problems related to ship noise were partially solved when A. J. Munday, who had worked with Dr. Elisha Gray on signaling by underwater bells to include actual messages, found that a microphone placed in a metal box filled with water and attached to a ship's skin from inside allowed clear reception. In further experiments placement of such microphones on each side of a ship allowed finding the direction of the source. Intensity on one side showed the source to that side of the ship and equal intensity showed the source to be directly ahead. A direction indicator box allowed the selection of receivers individually for comparison of signal strength for direction.
Experiments determined modifications to bells used in air that optimized them for underwater use. Electrical striking systems allowed the bells to be connected to surface aids. Canadian experiments showed the practicality of determining direction by comparison of the reception by two receivers mounted on each side of a vessel's bow.
Commercial production
The Submarine Signal Company, was established in Boston, Massachusetts, to turn the research into a navigational aid. The company developed, patented and began manufacturing electromechanical bell signals and shipboard receivers based on previous research, introducing the world's first electronic underwater acoustic navigation aid in 1901.
The signal system was of particular importance for safe navigation in fog. Fog signals, horns and whistles, conducted by air were unreliable and erratic. Sonic signals through water were more reliable and had more range. Offshore hazards could be marked by a tripod mounted bell connected to a shore station by cable. A similar system of underwater bells mounted on ships enabled signaling between ships to avoid collisions in fog. The Cunard liner Lucania was equipped with the first ship-to-ship submarine signal device.
The United States Lighthouse Board had some interest, but they did not take immediate action. The British Admiralty and Trinity House and, in Germany, the North German Lloyd Steamship Company took more immediate notice of the potential and became pioneers in implementation both at signal stations and as shipboard receivers. The German company Norddeutsche Maschinen und Armaturenfabrik (1902), becoming Atlas Werke in 1911, manufactured the system under license from the Submarine Signal Company. Major lines were equipping it ships with the apparatus so that in 1905, Cunard announced its entire fleet would have the apparatus after its experience with Lucania and Norddeutscher Lloyd liners , and were successfully using the system. An example of significant commercial advantage, being able to operate when other ships were fog bound, was a case in which the liner Kaiser Wilhelm II was able to enter harbor twenty-two hours before the fog at the Weser river mouth cleared and other vessels could enter port. By using the submarine signals of the entrance lightvessel the ship was able to enter the fog clear harbor to discharge passengers and cargo.
The Admiralty conducted tests in October 1906 using a bell such as was used by U.S. lightvessels. The tests were successful, with the Admiralty recommending their use as a coastal navigation aid with notes on the possible ship-to-ship use to warn and establish direction of another ship in fog. There was also notation of use between submarines and "parent ships", with some of the submarine results withheld from publication as purely military in application. Experience of U.S. Navy battleships in fog off Nantucket Shoals proved the fleet could, under reduced speed, safely navigate and maintain formation by using the signals.
Installations
On March 3, 1905, an act in the United States had authorized funding for aids including submarine signals. The U.S. lighthouse authorities were by the summer of 1906 installing signals, specifically at lightvessels stationed at Boston, Pollock Rip, Nantucket, Fire Island, and Sandy Hook. The United States and Canada were placing the signals at important locations. The U.S. Lighthouse Board was ordering systems for the Gulf of Mexico and Britain had adopted the system for all its aids to navigation. In 1910, the report of the United States Department of Commerce showed forty-nine signals established by June 30, most on lightvessels. Extension into the Great Lakes revealed a problem with the forepeak receiver installation for seagoing ships operated in light condition in fresh water. The forepeak was almost out of the water, thus reducing the effectiveness and requiring a solution by the Submarine Signal Company.
By 1907, the signals were in common use, with most large ships equipped with the receiving apparatus. The receiving apparatus had evolved from a simple receiver on the ship's bottom to two hydrophones in water-filled sea chests on each side of the ship, enabling the ship to determine the direction from which the signal came. The Submarine Signal Company, with branches in Bremen, Liverpool, London, and New York, was both manufacturing the apparatus and collecting data from shipping companies and individual ships on the operation of the signals.
The utility of the signals became evident as more stations and ships were equipped. Prominent ship captains, such as James Watt, master of Lusitania, strongly endorsed the system. Marine underwriters needed information on which ships were equipped to adjust risk for vessel and cargo insurance. The American Bureau of Shipping included whether a vessel was equipped with submarine signal apparatus as a part of the registry information along with wireless. Registers making note of navigation equipment of yachts and ships listed "Submarine Signal system" or "Sub.Sig." as seen in the yacht Noma and Lloyd's Register, column two, "Special surveys" for ships.
Technological advances
The Submarine Signal Company was the first company engaged in underwater acoustics, becoming the national underwater sound experts and producing acoustical aids to navigation. It also became the major sonar supplier to the U.S. Navy in later years.
A technique termed "synchronous signaling" combined bell signals with coordinated radio dot signals for direct distance to the signal without use of stopwatches. The radio dots would follow a bell strike sequence and the number of dots received before the next bell signal would indicate the distance in half miles. The stations with the capability and precise method to use the combined radio, including stations transmitting radio direction finding signals, and submarine signal were published in nautical notices and tables.
The Fessenden oscillator, invented by Submarine Signal Company's consulting engineer Reginald Fessenden in 1913 and developed and manufactured in 1914, was a transducer that was easier to install and maintain, could both send and receive, and also allowed coded communication between any two installations, including submarines. Bells were quickly phased out and transducer equipped installations remained active until World War II. The bells had been adequate to send signals, even coded strikes for identification, but the company had been seeking a method of acoustical communications. The oscillator accomplished that and led to further developments in underwater acoustics. The company acted quickly to replace the bells with the transducers and began working on their use in submarine telegraphy, but it was slow to recognize or take advantage of the sonic distance measurement of interest to Fessenden so that others took the lead in SOund NAvigation Ranging, now generally simply known as sonar.
Submarine signals during war
Submarine Signal Company's focus with the Fessenden device was on submarine telegraphy, with a beginning in submarine telephones. With marine radio gaining usage, the expensive submarine version faded. Despite Fessenden's demonstration in June 1914 of the effectiveness of his device in telegraphy, that aspect faded and the "sensing" potential, first crudely applied to locating icebergs, became critical with World War I and submarine warfare.
Full focus came to underwater acoustics and the potential to detect submarines by sound, either passively or actively. The existing receivers, designed to detect intentional signals, proved unable to detect the incidental sounds of submarines. Harold J. W. Fay of Submarine Signal Company was invited to meet with the Chief, Bureau of Steam Engineering 20 March 1917 to discuss establishing an acoustical research station at East Point, Nahant, Massachusetts. Fay gave assurances property would be made available. As implemented, Submarine Signal Company would be joined by Western Electric Company and General Electric Company to work on the project. On 8–9 May, representatives of the companies met in Washington to establish working relationships.
To meet concerns of the Naval Consulting Board that naval interests might not be met in general research, a Navy Special Board on Anti-Submarine Devices would oversee the work. Commander Clyde Stanley McDowell was secretary of the board and later filled the same function at the Naval Experimental Station, New London, Connecticut. The Nahant Antisubmarine Laboratory, completed April 7, 1917, was the first anti-submarine acoustical laboratory of the Navy. The laboratory, a cluster of buildings behind guarded security fencing, was where "submarine signals" research entered the new field of anti-submarine acoustics.
The submarine signals as navigational aids, just as many lights went dark, were stopped so as not to aid enemy submarines or become gathering points for target ships.
Submarine Signal Company merger with Raytheon
During World War I and after, the Submarine Signal Company expanded into fathometers and other marine electronics, including radio direction finders and radiotelephones, as acoustic aids faded in importance with the growing importance and adoption of radio navigation. In 1946, the company was acquired by and merged with the American Appliance Company, later Raytheon, to become that company's Marine Division responsible for all products with marine applications.
Footnotes
References
External links
Submarine Signals (Submarine Signal Company, background and list of ships, stations & detection range observations)
Illustrations in text describing technical details. (1914)
History of navigation
Navigational aids
Navigational equipment
Acoustics | Submarine signals | [
"Physics"
] | 2,547 | [
"Classical mechanics",
"Acoustics"
] |
63,381,174 | https://en.wikipedia.org/wiki/Whiteshift | Whiteshift: Populism, Immigration and the Future of White Majorities is a 2018 non-fiction book written by Eric Kaufmann, a professor at Birkbeck College, University of London. Described by The Economist as a "monumental study of ethno-demographic change", Whiteshift covers politics in both Europe and North America and looks into the political views of the populist right. Kaufmann argues that the rise of Donald Trump in America and the populist right in Europe is a reaction to sweeping demographic change rather than to "economic anxiety".
Reviews
On release, The Times made Whiteshift the 'Book of the Week' but with a sceptical review by David Aaronovitch, who called it "a big controversial book about a big controversial subject". Publishers Weekly said it was "likely to make a big splash", and The Financial Times listed it as one of the 'Best books of 2018' in the politics genre. The New Yorker wrote that Kaufmann and Whiteshift were defending white identity politics. Daniel Trilling, in the London Review of Books, was critical of the book, describing Kaufmann's frame of reference as "both too broad and too narrow".
Kenan Malik wrote that "Whiteshift is a hefty work crammed with data and graphs. The trouble with viewing the world primarily in demographic terms, though, is that, for all the facts and figures, it is easy to be blind to the social context."
In a review symposium about Whiteshift published in the journal Ethnicities, political scientist Robert Ford wrote that "There is much to admire here. Kaufmann is methodologically catholic and draws on a rich range of different resources to examine and interrogate evolving white identity politics." However, he also noted "Kaufmann’s rather Manichean account of white ethnic politics involves some curious omissions and misunderstandings" and that "lack of balance is a recurring feature of Kaufmann’s discussions about the competing claims of ethno-cultural whites, cosmopolitan whites and ethnic minorities." Sociologist John Holmwood argued that the lack of any discussion of "settler colonialism or of the place of first Nation populations and enslavement of African Americans and Jim Crow segregation in the USA" represent "serious – in fact, fatal – omissions in a book concerned to rehabilitate symbols of white identity." Holmwood writes that "It is a very large book – 619 pages – but it is also poorly edited, repetitive and, I have suggested, partial."
References
External links
Whiteshift on Abrams Books website
Populism and the Future of White Majorities on The Agenda with Steve Palkin, TVOntario
Episode 80: Eric Kaufmann, Whiteshift: Populism, Immigration and the Future of White Majorities on Half Hour of Heterodoxy
2018 non-fiction books
British non-fiction books
Books about race and ethnicity
Books about the United States
English-language non-fiction books
Works about White Americans
Demography
Allen Lane (imprint) books
Books about immigration | Whiteshift | [
"Environmental_science"
] | 631 | [
"Demography",
"Environmental social science"
] |
63,381,648 | https://en.wikipedia.org/wiki/Time%20in%20Vanuatu | Time in Vanuatu is given by Vanuatu Time (VUT; UTC+11:00). Vanuatu does not currently observe daylight saving time. Vanuatu previously observed DST (UTC+12:00) between 1 September 1983 until 1993.
IANA time zone database
In the IANA time zone database, Vanuatu is given one time zone:
References
External links
Time in Vanuatu at Lonely Planet
Current time in Vanuatu at Time.is
Geography of Vanuatu | Time in Vanuatu | [
"Physics"
] | 89 | [
"Spacetime",
"Physical quantities",
"Time",
"Time by country"
] |
63,384,362 | https://en.wikipedia.org/wiki/Postal%20codes%20in%20Oceania | Postcodes used in Oceania vary between the various sovereign nations, territories, and associated states in the region. Many of the smaller island regions in Oceania use postal code systems that are integrated into the postal systems of larger countries they are territories or associates of.
American states, territories, and states of association
In addition to the U.S. State of Hawai'i, there are two territories, one commonwealth, and three freely associated states within Oceania that are administered by the United States Postal Service (U.S.P.S.). All of these places use zip codes that start with the prefixes 967, 968, or 969. Standard USPS domestic rates apply to mail between the United States and these places.
Within the State of Hawai'i (postal abbreviation HI), zip code prefix 968 is generally reserved for Urban Honolulu, with all other areas prefixed 967 (shared with American Samoa).
Within the U.S. Territories, American Samoa (postal abbreviation AS) uses zip code 96799, and Guam (postal abbreviation GU) uses zip codes in the range 96910–96932.
Each major island of the Commonwealth of the Northern Mariana Islands (postal abbreviation MP) has its own zip code in the 96950-96952 range.
The nominally independent countries governed by the Compact of Free Association with the United States are also fully integrated into the U.S. Postal Service: The Federated States of Micronesia (postal abbreviation FM), the Marshall Islands (postal abbreviation MH), and Palau (postal abbreviation PW). Palau's abbreviation is derived from the word "Pelew", an old spelling for the archipelago. Two ZIP codes are used within Palau, with 96939 applying to the entire city of Ngerulmud, and 96940 referring to all other parts of Palau.
Australia
Postcodes were introduced in Australia in 1967 by the Postmaster-General's Department and are now managed by Australia Post, and are published in booklets available from post offices or online from the Australia Post website. Postcodes in Australia have four digits and are placed at the end of the Australian address.
French overseas territories
There are three French Overseas Départements or Territories in Oceania that are integrated into the postal code system of France: French Polynesia, New Caledonia, and Wallis and Futuna. Like Overseas Départements and Territories around the world, the French postal service uses 3-digit codes to refer to these places: 987 for French Polynesia, 988 for New Caledonia, and 986 for Wallis and Futuna.
New Zealand
Pitcairn Islands
The Pitcairn Islands is integrated into the postal code system of the United Kingdom.
References
Postal systems | Postal codes in Oceania | [
"Technology"
] | 567 | [
"Transport systems",
"Postal systems"
] |
63,384,990 | https://en.wikipedia.org/wiki/Mac%20OS%20Gujarati | Mac OS Gujarati is a character set developed by Apple Inc. It is an extension of the Gujarati portion of IS 13194:1991 (ISCII-91).
Code page layout
The following table shows the Mac OS Gujarati encoding. Each character is shown with its equivalent Unicode code point. Only the second half of the table (code points 128–255) is shown, the first half (code points 0–127) being the same as Mac OS Roman.
Byte pairs and ISCII-related features are described in the mapping file.
References
Character sets
Gujarati | Mac OS Gujarati | [
"Technology"
] | 116 | [
"Computing stubs",
"Digital typography stubs"
] |
63,385,148 | https://en.wikipedia.org/wiki/Mac%20OS%20Gurmukhi | Mac OS Gurmukhi is a character set developed by Apple Inc. It is an extension of the Gurmukhi portion of IS 13194:1991 (ISCII-91).
Code page layout
The following table shows the Mac OS Gurmukhi encoding. Each character is shown with its equivalent Unicode code point. Only the second half of the table (code points 128–255) is shown, the first half (code points 0–127) being the same as Mac OS Roman.
Byte pairs and ISCII-related features are described in the mapping file.
References
Character sets
Gurmukhi | Mac OS Gurmukhi | [
"Technology"
] | 128 | [
"Computing stubs",
"Digital typography stubs"
] |
63,385,893 | https://en.wikipedia.org/wiki/Post-chorus | In music, particularly Western popular music, a post-chorus (or postchorus) is a section that appears after the chorus. The term can be used generically for any section that comes after a chorus, but more often refers to a section that has similar character to the chorus, but is distinguishable in close analysis. The concept of a post-chorus has been particularly popularized and analyzed by music theorist Asaf Peres, who is followed in this article.
Characterization
Characterizations of post-chorus vary, but are broadly classed into simply a second chorus (in Peres's terms, a detached postchorus) or an extension of the chorus (in Peres's terms, an attached postchorus). Some restrict "post-chorus" to only cases where it is an extension of a chorus (attached postchorus), and do not consider the second part of two-part choruses (detached postchorus) as being a "post"-chorus.
As with distinguishing the pre-chorus from a verse, it can be difficult to distinguish the post-chorus from the chorus. In some cases they appear separately – for example, the post-chorus only appears after the second and third chorus, but not the first – and thus are clearly distinguishable. In other cases they always appear together, and thus a "chorus + post-chorus" can be considered a subdivision of the overall chorus, rather than an independent section.
Characterization of a post-chorus varies, beyond "comes immediately after the chorus"; Peres characterizes it by two conditions: it maintains or increases sonic energy, otherwise it is a bridge or verse; and contains a melodic hook (vocal or instrumental), otherwise it is a transition.
Examples
Detached post-choruses typically have distinct melody and lyrics from the chorus:
Chandelier (Sia, 2014): the chorus begins and ends with "I'm gonna swing from the chandelier / From the chandelier", while the post-chorus repeats instead "holding on", in "I'm holding on for dear life" and "I'm just holding on for tonight", and has a new melody, but the same chord progression as the chorus.
Lyrics of attached post-choruses typically repeat the hook/refrain from the chorus, with little additional content, often using vocables like "ah" or "oh". Examples include:
"Umbrella" (Rihanna, 2007): the chorus begins "When the sun shine, we shine together" and run through "You can stand under my umbrella / You can stand under my umbrella, ella, ella, eh, eh, eh", which is followed by three more repetitions of "Under my umbrella, ella, ella, eh, eh, eh", the last one adding another "eh, eh-eh". Here the division between chorus and post-chorus is blurred, as the "ella, ella" begins in the chorus, and was a play on the reverb effect.
"Shape of You" (Ed Sheeran, 2017): the chorus runs "I'm in love with the shape of you ... Every day discovering something brand new / I'm in love with your body", and the post-chorus repeats vocables and the hook "Oh—I—oh—I—oh—I—oh—I / I'm in love with your body", then repeats the end of the chorus, switching "your body" to "the shape of you": "Every day discovering something brand new / I'm in love with the shape of you"
"Girls Like You" (Maroon 5, 2018): the chorus runs "'Cause girls like you ... I need a girl like you, yeah, yeah ... I need a girl like you, yeah, yeah", and the post-chorus repeats the hook with added "yeah"s: "Yeah, yeah, yeah, yeah, yeah, yeah / I need a girl like you, yeah, yeah / Yeah yeah yeah, yeah, yeah, yeah / I need a girl like you".
Hybrids are also common (Peres: hybrid postchorus), where the post-chorus keeps the hook from the chorus (like an attached postchorus), but introduces some additional content (hook or melody, like a detached postchorus).
References
Formal sections in music analysis
Popular music | Post-chorus | [
"Technology"
] | 910 | [
"Components",
"Formal sections in music analysis"
] |
63,388,218 | https://en.wikipedia.org/wiki/European%20Federation%20of%20Organisations%20for%20Medical%20Physics | The European Federation of Organisations for Medical Physics (EFOMP) was founded in May 1980 in London to serve as an umbrella organisation representing the national Medical Physics societies in Europe. The office moved to Utrecht in January 2021. It is a non-profit organisation and aims to foster and coordinate the activities of its national member organisations, encourage exchange and dissemination of professional and scientific information, develop guidelines for education, training and accreditation programmes and to make recommendations on the responsibilities, organisational relationships and roles of medical physicists.
Structure
The federation consists of national member organisations (NMOs) representing medical physics in Europe, where only one NMO can represent the corresponding nation The number of representatives each NMO can send into the council depends on the number of national members. The council is the governing authority of EFOMP and normally meets once a year. The council elects the president and all other members of the executive and governing committees, it is responsible for maintaining the constitution of the federation, it handles all NMO related issues and sets up committees, foundations and other legal and operative bodies to facilitate the aims and purpose of the federation. The officers of the council are the members of the governing committee and the chairpersons of the committees.
The federation has six permanent committees:
Communications and Publications: is in charge of demonstrating the application of physical sciences to medicine to the public. The committee is responsible for the dissemination of information on EFOMP activities to enhance the education, competence, research and continuing professional development of medical physicists across Europe via digital channels of communications and publications (journal, newsletter Website, social media).
European and International Matters: represents the interest of the federation to the various bodies of the European Union and beyond and promotes international links among National Member Organizations and other professional bodies.
Education and Training: is responsible for supporting NMOs in providing educational approaches for physics in medicine
Professional Matters: is in charge of establishing and maintaining the recognition of the Medical Physicists as an academic profession in Europe bridging between physics and medicine and deals with professional issues related to the medical physics profession
Projects: is in charge of participation in and coordination of major European projects in close collaboration with national and international legal bodies
Science: is responsible for supporting the NMOs in setting up scientific activities and organizing ordinary meetings, promotes the operation of working groups on special topics and participates in the production of guidelines and policies describing good practice
National Member Organisations
EFOMP is the umbrella organisation for 37 nations, each of which are constituted by one medical physics organisation and each representing together more than 9000 medical physicists and clinical engineers working in the field of medical physics. Each national society has a certain number of delegates in the council, depending on the number of national members: up to 100 memberships result in one delegate, up to 400 entitles to two delegates and a society with 401 or more memberships can have three delegates.Each country can only be represented by one NMO. When multiple socitiees exist, these can be Associate Members.The Russian NMO terminated its membership in August 2022.
Associate Member Organisations
| || Lithuanian Association of Medical Physics and Biomedical Engineering (LMFBIA)|| 2009 || 2012 ||
The foundation date specifies the constitution of the earliest national organisation (separate society or division of superordinate organisation) of natural scientists or engineers working in a clinical environment which can be considered the predecessor of the NMO. The affiliation dates represent the earliest memberships of the current member nations (or its predecessor, e.g. Yugoslavia, Czechoslovakia) represented by a society.
European and international matters/projects
Several projects at European level with impact on medical physics matters and legislation have been undertaken. EFOMP is either in the advisory panel of multiple European projects or takes part in projects as a consortium member and endorses different projects that have an impact on and connection to medical physics profession, research, education as well as to the field of radiation protection.
One of the most important was the transposition of the Basic Safety Standards (BSS) Directive (Council Directive 2013/59/Euratom). After the BSS was brought into force in 2014, EFOMP headed a European consortium with the task to merge current scientific, technological and operational knowledge and experience with the consolidation of different directives and recommendations in the field of radiation protection. The objective of this project was to evaluate Member States‘ activities for the transposition and implementation of Council Directive in the medical area. In addition an exchange of initial experiences and resolutions was coordinated in order to identify good practices. In 2021, EFOMP has been involved in projects aimed to study the implementation of the Council Directive 2013/59/Euratom requirements for Medical Equipment with Respect to Monitoring and Control of Patient's Radiation Exposures, the analysis of workforce availability, education, and training needs to ensure quality and safety aspects of medical applications involving ionising radiation in the EU,the implementation of the Euratom and the EU legal bases with respect to the therapeutic uses of radiopharmaceuticals. All these studies are part of the European Union SAMIRA Strategic Agenda for Medical Ionising Radiation Applications and is the energy sector's contribution to Europe's Beating Cancer Plan.
MEDIRAD, has been one of the projects EFOMP was involved in during its preparation phase started by the European Union in 2017 dealing with implications of medical low dose radiation exposure and participated in work package six in order to formulate policy recommendations for the effective protection of patients and medical workers and the general public.
EFOMP has been a stakeholder in the ENEN project with an interest to build European Nuclear Competence through continuous Advanced and Structured Education and Training Actions.
Guidelines for manufacturers have been developed in 2019 jointly with the Coordination Committee of the Radiological, Electromedical and Healthcare IT Industry (COCIR), EFOMP and the European Society for Radiotherapy and Oncology (ESTRO) to meet the requirements of article 78.2 of the Basic Safety Standards (BSS) Directive (96/29/Euratom). The guidelines, developed also with the cooperation of the Heads of European Radiological Protection Competent Authorities (HERCA), provide guidance to manufacturers on how to compile information on radiological risk in an easy to use document, that is addressed to undertakings to help them carry out risk evaluation of radiotherapy departments, as required by article 63 and 78.2 of the BSS Directive.
Education and training
The EFOMP School for Medical Physics Experts (ESMPE) organizes medical physics education and training events specifically targeted to Medical Physicists who are already Medical Physics Experts (MPEs) or would like to achieve Medical Physics Expert status. Several editions were organised jointly with COCIR driven by the need for a closer cooperation between manufacturers and medical physicists to increase the awareness of features of medical devices related to imaging, radiotherapy and nuclear medicine. In 2019, EFOMP launched an e-learning platform, where pdfs and video recordings of the lectures given during the EFOMP school editions have been made available.
The main target of EFOMP is the harmonization of Medical Physics education and training standards throughout Europe. For this purpose, two elements have been implemented:
NMOs education and training scheme for medical physicists can be validated by the Professional Matters Committee and approved by the EFOMP Board of Officers. The long-term aim of the National Registration Scheme (NRS) is a generally accepted level of expertise, facilitating an exchange of professionals over Europe.
The European Examination board (EEB) awards the European Diploma of Medical Physics (EDMP) and the European Attestation Certificate to those Medical Physicists that have reached the Medical Physics Expert (EACMPE) level.
Science
Included in the scope of the federation is to coordinate scientific activities and to support the development of guidelines and directives. A number of Working groups are operating for a specific time period to create quality control protocols, guidance documents, harmonise practices update core curricula.
Every two years, EFOMP organizes the European Congress of Medical Physics (ECMP). The first congress took place in Athens (2016), the second one in Copenhagen (2018), the 3rd online due to COVID19 pandemic, the 4th in Dublin (2022), the forth will take place in Munich and the fifth in Valecia (2026).
Since 2007, Physica Medica the European Journal of Medical Physics (EJMP), is the official scientific journal of the organisation. The owner of the journal is the Italian Association of Medical Physics (AIFM) and it is also the official organ of the French (SFPM), Irish (IAPM), Czech Republic (CAMP) and Hellenic (HAMP) Societies of Medical Physics. In 2019, EJMP has become official publication of the International Organization for Medical Physics (IOMP). Every month a volume is published. According to the Institute for Scientific Information (ISI) the current Impact Factor is 2.532 (2018).
There are three other scientific journals that EFOMP is associated with:
Physiological Measurements owned by the Institute of Physics and Engineering in Medicine (IPEM)
European Radiology owned by the European Society of Radiology (ESR)
Physics in Medicine and Biology owned by IPEM
EFOMP publishes a quarterly electronic newsletter called the European Medical Physics News (EMPnews).
Co-operation
EFOMP created an international network of relationships with other stakeholders in the field of physical science applied to healthcare.
Collaborations:
regional organisation member of the International Organization for Medical Physics (IOMP)
collaborator with the International Atomic Energy Agency (IAEA) in the field of Radiation Protection for Patients
shareholder of the European Institute for Biomedical Imaging Research (EIBIR)
representative for medical physics in the organization Heads of European Radiological Protection Competent Authorities (HERCA)
associate member of the European Foundation for Training and Education in Radiation Protection (EUTERP)
liaison organisation of the International Commission on Radiological Protection (ICRP)
member of the Digital Imaging and Communications in Medicine (DICOM)
participant in the European Commission Initiative on Breast Cancer (ECIBC)
Memoranda of understanding:
American Association of Physicists in Medicine (AAPM)
European Association of Nuclear Medicine (EANM)
European Coordination Committee of the Radiological, Electromedical and Healthcare IT Industry (COCIR)
European Federation of Radiographer Societies (EFRS)
European Network for Training and Education of Medical Physics Experts (EUTEMPE-NET)
European Society for Magnetic Resonance in Medicine and Biology (ESMRMB)
European Society for Radiotherapy and Oncology (ESTRO)
European Society of Radiology (ESR)
European Society of Medical Imaging Informatics (EuSoMII)
European Radiation Dosimetry Group (EURADOS)
Middle East Federation Of Organizations of Medical Physics (MEFOMP)
Nuclear Medicine Europe (NMEU)
References
External links
Official Website of EFOMP
Medical physics
Medical physics organizations
International professional associations
Science and technology in Europe
Education in Europe
Organizations established in 1980
Federations | European Federation of Organisations for Medical Physics | [
"Physics"
] | 2,238 | [
"Applied and interdisciplinary physics",
"Medical physics"
] |
59,784,068 | https://en.wikipedia.org/wiki/Novolak | Novolaks (sometimes: novolacs) are low molecular weight polymers derived from phenols and formaldehyde. They are related to Bakelite, which is more highly crosslinked. The term comes from Swedish "lack" for lacquer and Latin "novo" for new, since these materials were envisioned to replace natural lacquers such as copal resin.
Typically novolaks are prepared by the condensation of phenol or a mixture of p- and m-cresol with formaldehyde (as formalin). The reaction is acid catalyzed. Oxalic acid is often used because it can be subsequently removed by thermal decomposition. Novolaks have a degree of polymerization of approximately 20-40. The branching density, determined by the processing conditions, m- vs p-cresol ratio, as well as CH2O/cresol ratio is typically around 15%.
Novolaks are especially important in microelectronics where they are used as photoresist materials. They are also used as tackifiers in rubber.
See also
Phenol formaldehyde resin
Epoxy
References
Plastics
Synthetic resins
Semiconductor device fabrication
Thermosetting plastics | Novolak | [
"Physics",
"Chemistry",
"Materials_science"
] | 250 | [
"Synthetic resins",
"Microtechnology",
"Synthetic materials",
"Unsolved problems in physics",
"Semiconductor device fabrication",
"Amorphous solids",
"Plastics"
] |
59,784,486 | https://en.wikipedia.org/wiki/Marie-Paule%20Kieny | Marie-Paule Kieny is a French virologist, vaccinologist, public health expert and science writer. She is currently director of research at INSERM and chief of the board at DNDi.
Education
Kieny completed her PhD in microbiology in 1980 at the University of Montpellier, and received her Habilitation à Diriger des Recherches in 1995 from the University of Strasbourg.
Kieny was presented with an honorary doctorate from the Autonomous University of Barcelona in 2019 for her commitment to public health and worldwide universal health care.
Career
After completing her PhD, Kieny took up a position at Transgene SA, Strasbourg, as assistant scientific director under scientific director Jean-Pierre Lecocq until 1988.
Kieny became director of research at Inserm for the first time between 1999 and 2000. Kieny was a member of the European Vaccine Initiative until 2010.
Kieny was vaccine research director of WHO from 2002 to 2010, most notably during the 2009 swine flu pandemic. She was promoted to assistant director-general, playing a major leadership role during the Ebola virus epidemic in West Africa and the 2015–16 Zika virus epidemic. Kieny even audaciously signed up herself as a test subject for the safety of new Ebola vaccines being developed, amidst concerns over the logistics and ethics of testing early-stage therapeutics and preventatives for ebola in the context of an ongoing epidemic. Given the slow development of new therapies in response to the outbreak, Kieny and colleagues began making a framework to speed up development and encourage researchers to share data openly without worrying about being scooped. She commented on the successful development of efficacious vaccines for deployment in a future outbreak. In aftermath of the 2014 Democratic Republic of the Congo Ebola virus outbreak Kieny stated that the vaccine may not be required since the outbreak was not as serious as previously feared. Kieny was involved also in addressing the ongoing antimicrobial resistance crisis with WHO, overseeing the first WHO Model List of Essential Medicines to include guidance on proper use of antibiotics within the framework of universal health care. She helped prepare a list of Antibiotic resistant bacteria which should be prioritised for research beyond just Extensively drug-resistant tuberculosis, such as Acinetobacter baumannii and Pseudomonas aeruginosa strains resistant to Carbapenem.
Kieny was one of seven vaccine experts interviewed in 2012 by Wired about what the next decade held for vaccine innovation.
In 2017 she joined the board of directors for the Human Vaccines Project, was made interim director of the Medicines Patent Pool (MPP), and joined the Drugs for Neglected Diseases Initiative (DNDi) as chief of the board. As head of MPP, Kieny oversaw the licensing of the Hepatitis C drug Mavyret for generic production.
Other activities
BioMérieux, Independent Member of the Board of Directors
Fondation Mérieux, Chair of the Scientific Advisory Board
GISAID, Member of the Nomination Committee, Advisor
Global Antibiotic Research and Development Partnership (GARDP), Member of the Board of Directors
Joint Programming Initiative on Antimicrobial Resistance (JPIAMR), Member of the Management Board
Solthis – Therapeutic Solidarity and Initiatives for Health, Member of the Board of Directors
Vanke School of Public Health at Tsinghua University, Member of the International Advisory Board
Wellcome Trust, Chair of the Strategic Advisory Board on Vaccines and Drug-resistant Infections
Wellcome Trust, Member of the Strategic Advisory Board on Innovation
Awards
2017 Inserm International Prize.
1994 Prix Génération 2000-Impact Médecin
1991 Prix de l'Innovation Rhône-Poulenc
Decorations
2021 Officier de l'Ordre national du Mérite (chevalier in 2000)
2016 Chevalier de la Legion d'honneur.
References
University of Montpellier alumni
University of Strasbourg alumni
French women biologists
Vaccinologists
French virologists
Women virologists
World Health Organization officials
Inserm directors | Marie-Paule Kieny | [
"Biology"
] | 819 | [
"Vaccination",
"Vaccinologists"
] |
59,784,832 | https://en.wikipedia.org/wiki/Kairbaan%20Hodivala-Dilke | Kairbaan Hodivala-Dilke, FMedSci is an English cell biologist who has made significant contributions to the understanding of the cellular and molecular biology of the tumour microenvironment and in particular angiogenesis. She is Professor of Angiogenesis and the Tumour Microenvironment and Deputy Institute Director of Barts Cancer Institute, Queen Mary University of London. In 2015 she was awarded the Hooke medal from the British Society for Cell Biology and EMBO membership.
Early life
Hodivala-Dilke was born to an Indian Parsi family in South West London.
Education and academic career
Hodivala-Dilke's scientific career started as a technical assistant, first at The Jodrell Laboratories, Kew Gardens, and later in the Wellcome Trust funded Malaria Research team at Imperial College, London. Following a BSc in Biology at the University of Southampton, Hodivala-Dilke studied for a PhD in epithelial cell biology with Fiona Watt at Imperial Cancer Research Fund (now part of the Francis Crick Institute) in London. Hodivala-Dilke then moved to The Massachusetts Institute of Technology, for a postdoctoral fellowship with Richard Hynes.
Hodivala-Dilke returned to the UK as an Imperial Cancer Research Fund tenure-track fellow, mentored by Professor Ian Hart, first at St. Thomas’ Hospital and later at Barts Cancer Institute. In 2004 Hodivala-Dilke was awarded tenure and in 2009 became Professor of Angiogenesis. Hodivala-Dilke became Deputy Director of the Barts Cancer Institute in 2012.
Research interests
During her studies at The Massachusetts Institute of Technology, Hodivala-Dilke studied adhesion molecules called integrins and her findings support that epidermal α3β1 integrin is required for the prevention of blistering diseases and that αvβ3-integrin is required for blood clotting. Subsequently her research interests have been directed to revealing the role that adhesion related molecules have in blood vessel formation (angiogenesis). Her finding that αvβ3-integrin acts as a negative regulator of pathological angiogenesis rather than promoting the growth of new blood vessels, highlighted the requirement for more investigation of how αv-integrin antagonists act in anti-angiogenic treatments.
Studies of a mouse model of Down syndrome have found that 3 copies of some chromosome 21 genes can impede the growth of blood vessels in tumours. These mice provide a system to discover new regulators of blood vessel growth. Recent investigations have increased understanding of the role that stromal focal adhesion kinase (FAK) plays in tumour growth, progression and resistance to chemotherapy. Hodivala-Dilke's research goal is to study how the tumour microenvironment can control tumour progression and cancer treatment efficacy.
Hodivala-Dilke’s team at Barts Cancer Institute have established the role of stromal focal adhesion kinase (FAK) in chemoresistance. The team have pioneered a novel concept in vascular promotion using low doses of RGD mimetics in enhancing the efficacy of cancer therapy. The team’s overall goal is to discover novel therapeutic vascular targets to modulate stromal control in the control of cancer.
Professional associations and awards
In 2015, Hodivala-Dilke was awarded EMBO membership.
In 2015, Hodivala-Dilke was awarded the Hooke medal from the British Society for Cell Biology.
In 2016, Hodivala-Dilke became an elected member of the Academy of Medical Sciences.
References
British biologists
Fellows of the Academy of Medical Sciences (United Kingdom)
Parsi people
Angiogenesis inhibitors
Academics of Barts and The London School of Medicine and Dentistry
Members of the European Molecular Biology Organization
Alumni of Imperial College London
Alumni of the University of Southampton
Massachusetts Institute of Technology alumni
Cancer researchers
Year of birth missing (living people)
Living people
Francis Crick Institute alumni
English people of Parsi descent | Kairbaan Hodivala-Dilke | [
"Biology"
] | 839 | [
"Angiogenesis",
"Angiogenesis inhibitors"
] |
59,785,705 | https://en.wikipedia.org/wiki/Elisabeth%20Larsson%20%28scientific%20computing%29 | Elisabeth Larsson (born December 30, 1971) is a Swedish applied mathematician and numerical analyst. She is a professor in the Department of Information Technology of Uppsala University, and the director of the Uppsala Multidisciplinary Centre for Advanced Computational Science.
Research
Larsson's research involves the applications of radial basis functions to scientific computing. It has included work on the propagation of sound waves through water, pricing of financial options, and simulation of the Earth's climate.
Education and career
Larsson was born on December 30, 1971 in Ljusdal, and went to high school in Ljusdal. She earned a master's degree in engineering physics at Uppsala University in 1994, and completed a Ph.D. in numerical analysis at Uppsala University in 2000. Her dissertation was Domain Decomposition and Preconditioned Iterative Methods for the Helmholtz Equation. Her doctorate was supervised by Kurt Otto, with as outside examiner.
She became a junior researcher in the Department of Information Technology at Uppsala University in 2001, and an assistant professor in 2007. She was promoted to senior lecturer (associate professor) in 2011 and professor in 2020.
Recognition
In 2007, Larsson was one of two winners of the Göran Gustafsson Award for outstanding young Swedish scientists.
References
External links
Home page
1971 births
Living people
20th-century Swedish mathematicians
21st-century Swedish mathematicians
Applied mathematicians
Numerical analysts
Academic staff of Uppsala University
20th-century women mathematicians
21st-century women mathematicians
Swedish women mathematicians
Scientific computing researchers
20th-century Swedish women | Elisabeth Larsson (scientific computing) | [
"Mathematics"
] | 304 | [
"Applied mathematics",
"Applied mathematicians"
] |
59,786,049 | https://en.wikipedia.org/wiki/Jacobo%20Bielak | Jacobo Bielak is a Mexican-born earthquake engineer. Bielak was raised in Mexico City and earned his bachelor's of science degree from the National Autonomous University of Mexico in 1963. He subsequently attended Rice University in the United States, completing his master's degree in 1966, followed by a doctorate from the California Institute of Technology, graduating in 1971. Bielak taught at Carnegie Mellon University, where he was named Hamerschlag University Professor of Civil and Environmental Engineering, and granted emeritus status upon retirement in 2018.
In 2018, he and his collaborators completed the Quake Project, which helped predict how earthquakes impact urban infrastructure. His early work was the basis for the soil-structure seismic provisions within the National Earthquake Hazards Reduction Program (NEHRP).
Bielak was awarded the Gordon Bell Prize in 2003 for computational research on the effects of future earthquakes in Los Angeles. He was elected to membership of the United States National Academy of Engineering in 2010 "for advancing knowledge and methods in earthquake engineering and in regional-scale seismic motion simulation."
References
20th-century American engineers
21st-century American engineers
Mexican civil engineers
American structural engineers
Environmental engineers
National Autonomous University of Mexico alumni
Rice University alumni
Mexican emigrants to the United States
California Institute of Technology alumni
Engineers from Mexico City
Members of the United States National Academy of Engineering
Year of birth missing (living people)
Living people | Jacobo Bielak | [
"Chemistry",
"Engineering"
] | 278 | [
"Environmental engineers",
"Environmental engineering"
] |
59,786,675 | https://en.wikipedia.org/wiki/Takashi%20Asano | is a Japanese-born environmental engineer and a professor emeritus at the University of California, Asano has more than 40 years of academic and professional experience in environmental and water resources engineering, specializing in water reclamation, recycling, and reuse. During 1978–1992, he served as the water reclamation specialist for the California State Water Resources Control Board (SWRCB) in Sacramento, during the formative years of water reclamation, recycling, and reuse. Asano has conducted water reclamation and reuse studies at the SWRCB and the University of California at Davis, many of which contributed to the scientific and technical basis for State of California's Title 22 regulations (State of California Water Recycling Criteria). Previously, Asano taught at Montana State University, Bozeman, 1971–75, and Washington State University, Pullman, 1975–78. He has continued to lecture widely and publish on topics current and ancient.
Asano co-authored with Franklin L. Burton, Harold L. Leverenz, Ryujiro Tsuchihashi, and George Tchobanoglous the widely used textbook entitled Water Reuse: Issues, Technologies, and Applications by the McGraw-Hill Companies, Inc., New York, NY.
Awards and honors
For his research on quantitative microbial risk analysis and groundwater recharge, Asano was awarded the 1999 Jack Edward McKee Medal by the Water Environment Federation (WEF), which was shared by Hiroaki Tanaka (Kyoto University, Japan) as well as Asano's colleagues, Edward D. Schroeder and George Tchobanoglous at the University of California at Davis.
Asano was awarded the Stockholm Water Prize in August 2001. That same year, Asano was elected a member of the European Academy of Sciences and Arts. In 2004, Asano was awarded an Honorary Doctorate Degree from his alma mater, Hokkaido University in Sapporo, Japan. The Government of Japan honored him with the Order of the Sacred Treasure, Gold and Silver Star, in Spring 2009. In addition, in 2008, he was awarded the Doctor Honoris Causa distinction by the University of Cádiz, Spain for his contributions in water reuse studies in the Mediterranean region.
References
1937 births
Living people
Japanese civil engineers
Environmental engineers
University of California, Davis faculty
UC Berkeley College of Engineering alumni
University of Michigan College of Engineering alumni
People from Sapporo
Members of the European Academy of Sciences and Arts
American academics of Japanese descent
Japanese emigrants to the United States | Takashi Asano | [
"Chemistry",
"Engineering"
] | 504 | [
"Environmental engineers",
"Environmental engineering"
] |
59,787,278 | https://en.wikipedia.org/wiki/J%C3%B6rg%20Imberger | Jörg Imberger (born September 10, 1942) is an Australian civil engineer.
Imberger studied civil engineering at the University of Melbourne, graduating with a bachelor's degree in 1963. He pursued further study in the subject at the University of Western Australia, completing a master's degree in 1966. Imberger earned his doctorate in civil engineering with specialization in coastal engineering from the University of California, Berkeley in 1970. Imberger began teaching as an associate professor at Berkeley in 1976. He returned to Australia to assume the Winthrop Professorship at the University of Western Australia in 1979. After his retirement in 2015, Imberger accepted an adjunct professorship at the University of Miami.
Over the course of his career, Imberger has received the Peter Nicol Russell Memorial Medal (1995), the Stockholm Water Prize (2001), and the A.C. Redfield Lifetime Achievement Award (2007), among others. He became a member of the Order of Australia in 1992, and a fellow of the Australian Academy of Science in 1993. Imberger has been elected to an equivalent honor within the Australian Academy of Technological Sciences and Engineering, as well as the Institute of Engineers, Australia, American Geophysical Union (2007), and Royal Academy of Engineering (2008). In 2006, he was elected a member of the National Academy of Engineering for contributions to and international leadership in the environmental fluid dynamics of lakes, reservoirs, estuaries, and coastal seas.
References
External links
1942 births
Living people
Australian civil engineers
Environmental engineers
University of Western Australia alumni
Academic staff of the University of Western Australia
UC Berkeley College of Engineering alumni
UC Berkeley College of Engineering faculty
University of Melbourne alumni
Members of the Order of Australia
Foreign associates of the National Academy of Engineering
Fellows of the Australian Academy of Technological Sciences and Engineering
Fellows of the Australian Academy of Science
Fellows of the American Geophysical Union
Fellows of the Royal Academy of Engineering
Australian expatriates in the United States
20th-century Australian engineers
21st-century Australian engineers | Jörg Imberger | [
"Chemistry",
"Engineering"
] | 395 | [
"Environmental engineers",
"Environmental engineering"
] |
59,787,510 | https://en.wikipedia.org/wiki/Jacqueline%20Chen | Jacqueline H. Chen is an American mechanical engineer. She works in the Combustion Research Facility of Sandia National Laboratories, where she is a Senior Scientist. Her research applies massively parallel computing to the simulation of turbulent combustion.
Education and career
Chen grew up as a child of Chinese immigrants in Ohio,
and graduated from the Ohio State University with a bachelor's degree in mechanical engineering in 1981. After earning a master's degree in mechanical engineering in 1982 at the University of California, Berkeley, under the mentorship of Boris Rubinsky, she continued at Stanford University for doctoral study in the same subject. She completed her Ph.D. in 1989; her doctoral advisor at Stanford was Brian J. Cantwell.
She has worked at Sandia since finishing her education and is a pioneer of massively parallel direct numerical simulation of turbulent combustion with complex chemistry . She has led teams of computer scientists, applied mathematicians and computational engineers on the co-design of combustion simulation software for exascale computing (10^18 flops).
Recognition
In 2018, Chen was elected to the National Academy of Engineering "for contributions to the computational simulation of turbulent reacting flows with complex chemistry".
In the same year, the Society of Women Engineers gave her an Achievement Award, their top honor, and the Combustion Institute awarded her the Bernard Lewis Gold Medal, "for her exceptional skill in linking high performance computing and combustion research to deliver fundamental insights into turbulence-chemistry interactions". The Combustion Institute and the American Physical Society also named her as one of its fellows.
References
External links
Year of birth missing (living people)
Living people
American women engineers
American mechanical engineers
American people of Chinese descent
Fellows of the American Physical Society
Fellows of the Combustion Institute
Computational fluid dynamicists
Scientific computing researchers
Ohio State University College of Engineering alumni
UC Berkeley College of Engineering alumni
Stanford University School of Engineering alumni
Members of the United States National Academy of Engineering
Sandia National Laboratories people
21st-century American women | Jacqueline Chen | [
"Chemistry"
] | 391 | [
"Fellows of the Combustion Institute",
"Combustion"
] |
59,788,102 | https://en.wikipedia.org/wiki/Well-known%20text%20representation%20of%20coordinate%20reference%20systems | Well-known text representation of coordinate reference systems (WKT or WKT-CRS) is a text markup language for representing spatial reference systems and transformations between spatial reference systems. The formats were originally defined by the Open Geospatial Consortium (OGC) and described in their Simple Feature Access and Well-known text representation of coordinate reference systems specifications. The current standard definition is ISO 19162:2019. This supersedes ISO 19162:2015.
Version history
This WKT format was initially defined by the Open Geospatial Consortium (OGC) in 1999, then extended in 2001. This format, also defined in ISO 19125-1:2004, is sometime known as "WKT 1". Later, evolution of the Coordinate Reference System conceptual model, new requirements and inconsistencies in implementation of WKT 1 format between different software have encouraged the revision of that format. The updated "Well-known text representation of coordinate reference systems" standard, sometime known as "WKT 2", was adopted by the Open Geospatial Consortium in 2015. This standard is published conjointly by the International Organization for Standardization as ISO 19162:2015.
Confusingly, the original 2015 "WKT 2" standard has a version number 1 for the new, stricter WKT-CRS specification. A newer revision called WKT-CRS 2 was published in 2018, with the ISO version being ISO 19162:2019.
Backward compatibility
A software capable to read coordinate reference systems in WKT 2 format can also read many (but not all) equivalent systems in WKT 1 format. Some caveats exist, notably the removal of the TOWGS84 element which is replaced by the BOUNDCRS element. Another caveat is about the units of measurement. Some of them were unspecified in oldest WKT 1 specifications (for example the PRIMEM unit), which has led to different interpretations by different software. Those units of measurement have been clarified in the 2001 update and the WKT 2 specification is consistent with that clarification. But not all software have followed the 2001 clarification.
ESRI vs OGC
Esri, which also participated in writing the WKT 2 specification, had a few variations on OGC's WKT 1 specification, making it stricter and contain less ambiguities. As a result, some databases differentiate between "OGC WKT" and "ESRI WKT" representations. The problem is largely resolved in WKT 2, as it is better-defined. One distinction is that it does not have TOWGS84, much like WKT 2.
Coordinate reference systems
WKT can describe coordinate reference systems.
For example, the WKT below describes a two-dimensional geographic coordinate reference system with a latitude axis first, then a longitude axis. The coordinate system is related to Earth by the WGS84 geodetic datum:
GEODCRS["WGS 84",
DATUM["World Geodetic System 1984",
ELLIPSOID["WGS 84", 6378137, 298.257223563, LENGTHUNIT["metre", 1]]],
CS[ellipsoidal, 2],
AXIS["Latitude (lat)", north, ORDER[1]],
AXIS["Longitude (lon)", east, ORDER[2]],
ANGLEUNIT["degree", 0.0174532925199433]]
The WKT format can describe not only geographic coordinate reference systems, but also geocentric, projected, vertical, temporal and engineering ones (for example a coordinate reference system attached to a boat). The standard describes how to combine those coordinate reference systems together.
Coordinate operations
A WKT format is defined to describe the operation methods and parameters used to convert or transform coordinates between two different coordinate reference systems. The WKT 1 and WKT 2 formats are incompatible regarding coordinate operations, because of differences in the modelling. Below is an example of a concatenation of two WKT 1 transformation descriptions, where the Mercator projection is applied first and then an affine transform is applied on the result:
CONCAT_MT[
PARAM_MT["Mercator_2SP",
PARAMETER["semi_major",6370997.0],
PARAMETER["semi_minor",6370997.0],
PARAMETER["central_meridian",180.0],
PARAMETER["false_easting",-500000.0],
PARAMETER["false_northing",-1000000.0],
PARAMETER["standard parallel 1",60.0]],
PARAM_MT["Affine",
PARAMETER["num_row",3],
PARAMETER["num_col",3],
PARAMETER["elt_0_1",1],
PARAMETER["elt_0_2",2],
PARAMETER["elt 1 2",3]]]
Below is an example of a datum shift operation in WKT 2 format. Contrarily to an equivalent description in WKT 1 format, the WKT 2 description specifies the source and target coordinate reference systems, together with the domain of validity and the accuracy (in metres) that we can expect from this operation:
COORDINATEOPERATION["AGD84 to GDA94 Auslig 5m",
SOURCECRS[…full CRS definition required here but omitted for brevity…],
TARGETCRS[…full CRS definition required here but omitted for brevity…],
METHOD["Geocentric translations", ID["EPSG", 1031]],
PARAMETER["X-axis translation", -128.5, LENGTHUNIT["metre", 1]],
PARAMETER["Y-axis translation", -53.0, LENGTHUNIT["metre", 1]],
PARAMETER["Z-axis translation", 153.4, LENGTHUNIT["metre", 1]]
OPERATIONACCURACY[5],
AREA["Australia onshore"],
BBOX[-43.7, 112.85, -9.87, 153.68]]
APIs that provide support
Apache Spatial Information System: parses and formats WKT versions 1 and 2 for coordinate reference systems and coordinate operations
PROJ
See also
Well-known text representation of geometry
References
External links
Coordinate Transformation Service Specification
OGR projection tutorial
Spatial reference system well-known text format version 1
Spatial reference system well-known text format version 2
ISO Spatial standard (there is a charge for this)
Map projections
GIS file formats
Markup languages | Well-known text representation of coordinate reference systems | [
"Mathematics"
] | 1,399 | [
"Map projections",
"Coordinate systems"
] |
59,788,104 | https://en.wikipedia.org/wiki/Von%20Bertalanffy%20function | The von Bertalanffy growth function (VBGF), or von Bertalanffy curve, is a type of growth curve for a time series and is named after Ludwig von Bertalanffy. It is a special case of the generalised logistic function. The growth curve is used to model mean length from age in animals. The function is commonly applied in ecology to model fish growth and in paleontology to model sclerochronological parameters of shell growth.
The model can be written as the following:
where is age, is the growth coefficient, is the theoretical age when size is zero, and is asymptotic size. It is the solution of the following linear differential equation:
Seasonally-adjusted von Bertalanffy
The seasonally-adjusted von Bertalanffy is an extension of this function that accounts for organism growth that occurs seasonally. It was created by I. F. Somers in 1988.
See also
Gompertz function
Monod equation
Michaelis–Menten kinetics
References
Growth curves
Mathematical modeling | Von Bertalanffy function | [
"Mathematics"
] | 216 | [
"Applied mathematics",
"Mathematical modeling"
] |
59,791,457 | https://en.wikipedia.org/wiki/Shading%20coil | A shading coil or shading ring (Also called Frager spire or Frager coil) is one or more turns of electrical conductor (usually copper or aluminum) located in the face of the magnet assembly or armature of an alternating current solenoid. The alternating current in the energized primary coil induces an alternating current in the shading coil. This induced current creates an auxiliary magnetic flux which is 90 degrees out of phase from the magnetic flux created by the primary coil.
Because of the 90 degree phase difference between the current in the shading coil and the current in the primary coil, the shading coil maintains a magnetic flux and hence a force between the armature and the assembly while the current in the primary coil crosses zero. Without this shading ring, the armature would tend to open each time the main flux goes through zero and create noise, heat and mechanical damages on the magnet faces, so it reduces bouncing or chatter of relay or power contacts.
Shaded-pole AC motors
A shaded-pole motor is an AC single phase induction motor. Its includes an auxiliary winding composed of a copper ring called a shading ring (or shading coil with more than one turn).
The auxiliary winding produces a secondary magnetic flux which, along with the flux from the primary coil, forms a rotating magnetic field suitable for applying torque to and rotating the rotor. These devices are typically used as low-cost motors for microwave oven fans.
References
External links
Engineer's Relay Handbook, 5th edition, published by the Relay and Switch Industry Association (RSIA) – formerly NARM
Information about relays and the Latching Relay circuit
"Harry Porter's Relay Computer", a computer made out of relays
"Relay Computer Two", by Jon Stanley
AC motors
Electromagnetic components
Power engineering
Relays | Shading coil | [
"Engineering"
] | 367 | [
"Power engineering",
"Electrical engineering",
"Energy engineering"
] |
59,791,938 | https://en.wikipedia.org/wiki/Leichte%20Sprache | (; LS, literally: easy language) is a specific (usually written) version of the German language. It is directed to people who have low competences in German or in reading in general. The rules are published by the German association , which was established in 2006. The rules deal with the creation of sentences and the choice of words and makes recommendations about typography and the use of media. The content is often simplified as well, for example, LS encourages to write a long time ago instead of 1871. However, the language as such is not altered. LS is supposed to serve accessibility.
A similar concept is , which is less regulated and closer to standard German. Its target group are people with cognitive challenges and people with a different first language than German.
Several intellectuals and journalists have criticised texts in LS, for example after it was used additionally by the Bremen authorities for the regional elections of 2015. According to them, LS does not take readers seriously and simplifies the content too much. In 2017, journalist Alfred Dorfer mocked LS on Austrian teletext and apologized later after having spoken to people who benefit from LS texts.
Some of the rules of LS:
Write short sentences.
Use one sentence per line.
Use one sentence for one statement.
Use active voice.
Do not use conditional mood.
A sentence should be formed with the elements subject + predicate + object.
Do not use synonyms.
Split compound words: Write , not .
LS is not directed to children and should address the readers as adults, using the normal (formal) pronouns.
German law
In Germany, a law (§ 11, ) requires the authorities to provide information more and more in LS. The federal government enforces the use of LS by the authorities and their competences to write texts in LS.
See also
Easy read
Special English
References
German language
Accessibility
Special education in Germany
Simplified languages
2006 establishments in Germany | Leichte Sprache | [
"Engineering"
] | 395 | [
"Accessibility",
"Design"
] |
59,792,601 | https://en.wikipedia.org/wiki/4-Amino-5-hydroxymethyl-2-methylpyrimidine | Within the field of biochemistry, 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) also known as toxopyrimidine together with its mono phosphate (HMP-P) and pyrophosphate (HMP-PP) esters are biogenetic precursors to the important biochemical cofactor thiamine pyrophosphate (TPP), a derivative of thiamine (vitamin B1).
HMP, HMP-P and HMP-PP are found along with thiamine forms in a wide variety of living organisms. Thiamine in various salt, formulation and biological matrix forms are used to supplement human and animal diets because these organisms lack the capability to produce it. Methodologies are being sought for biotechnology-based production of thiamine forms and for increasing thiamine content in food sources.
TPP biogenesis
In microorganisms and plants TPP results from coupling of pyrimidine fragment HMP-PP with thiazole fragment HET-P to give thiamine monophosphate, followed by conversion to the pyrophosphate.
Biogenesis of HMP-P and HET-P vary with types of organism.
HMP-P biogenesis
In bacteria, HMP-P arises by conversion of the purine biosynthetic precursor 5-aminoimidazole ribotide (AIR) through the action of enzymes such as phosphomethylpyrimidine synthase, a member of the radical SAM superfamily. Studies using isotopically labelled AIR have shown which atoms carry into the product. Mechanisms by which this occurs are not yet known with certainty.
In yeasts, HMP-P is derived from metabolites of histidine and pyridoxine. Some of these transformations appear to be catalyzed by radical SAM enzymes. Isotopically labelled precursors have been used to investigate this biogenesis. Mechanisms of the transformations are unknown.
In Salmonella, HMP-P can be derived independently of purine biogenesis when AICAR is available.
In algae, thiamine forms and precursors are scavenged by uptake from water of exogenous products from other organisms. In higher plants, thiamine biogenesis resembles that of bacteria. In some circumstances, thiamine forms and precursors may be obtained through symbiotic relationships with microorganisms in the soil.
Genes relevant for transformations in the biogenesis of HMP-P, HET-P, and TPP have been identified in various organisms and some of the proteins resulting from their expression have been characterized. Biosynthesis of TPP is feedback inhibited through actions of a riboswitch.
Research is ongoing towards understanding biochemistry involved and towards facilitating technologies of socioeconomic value for supply of thiamine in various forms.
Related technologies
Commercially available salts thiamine chloride and thiamine nitrate are produced at scales of thousands of tons annually by chemistry-based manufacturing processes in Europe and Asia. These salts are supplied for formulations for supplementation of human diet and as feed additives for cattle, swine, poultry and fish.
Research for potential biotechnology-based production of thiamine has resulted in patent applications claiming fermentation using recombinant microorganisms modified to deregulate feedback inhibition and allow release of thiamine forms to the media as demonstrated at small scale.
Thiamine forms and their bio-precursors are produced at very large scale in biological matrices such as yeast, grains, plants and meats widely consumed as food and feed. Research into genetic modification of plants. has led to higher levels of thiamine in foodstuffs, such as rice. Use of thiamine forms and their bio-precursors by various means such as seed coating or soil and foliar fertilization to improve plant growth and properties are being investigated.
References
Biochemistry
Phosphates
Thiamine
Pyrimidines | 4-Amino-5-hydroxymethyl-2-methylpyrimidine | [
"Chemistry",
"Biology"
] | 819 | [
"Biochemistry",
"Phosphates",
"nan",
"Salts"
] |
59,793,473 | https://en.wikipedia.org/wiki/Windshield%20phenomenon | The windshield phenomenon (or windscreen phenomenon) is the observation that fewer dead insects accumulate on the windshields and front bumpers of people's cars since the early 2000s. It has been attributed to a global decrease of insect populations caused by human activity, e.g. use of pesticides.
Background
As early as the 2000s it became a commonplace observation among drivers that after a long drive, windshields no longer had to be cleaned of numerous insects. In 2016, Canadian naturalist John Acorn noted that the phenomenon had recently become a meme but questioned whether it is "reasonable to assume that windshields can tell us something about the overall numbers of insects" and also that "humans are notoriously bad at detecting trends". The windshield phenomenon was discussed widely in 2017 after major publications and other media reported the topic of reductions of insect abundance during the last few decades. Entomologists stated that they had noticed that they no longer had to clean their windshields frequently.
Studies
Denmark
A 20-year study measured the number of dead insects on car windshields on two stretches of road in Denmark from 1997 until 2017. Adjusted for variables such as time of day, date, temperature, and wind speed, the research found an 80% decrease of the number of insects. A parallel study using sweep nets and sticky plates in the same area correlated positively with the reduction of insects killed by cars.
United Kingdom
In 2004 the Royal Society for the Protection of Birds (RSPB) asked 40,000 motorists in the United Kingdom to attach a sticky PVC film to their number plate. One insect collided with the plate for every driven. No historical data was available for comparison in the UK. A follow-up study by Kent Wildlife Trust in 2019 used the same methodology as the RSPB survey and resulted in 50% fewer impacts. The research also found that modern cars, with a more aerodynamic body shape, killed more insects than boxier vintage cars. Another survey was conducted in 2021 by Kent Wildlife Trust and nature conservation charity Buglife, which showed the number of insects sampled on vehicle number plates in Kent decreased by 72% compared to the 2004 results.
References
Extinction
Insects
Car windows
Roadkill | Windshield phenomenon | [
"Biology"
] | 439 | [
"Animals",
"Insects"
] |
59,793,942 | https://en.wikipedia.org/wiki/Post%20PNG | Post PNG is the organisation responsible for postal service in Papua New Guinea. It is a member of the Universal Postal Union and was created by the Postal Services Act 1996.
Post PNG operates 40 post offices and has around 350 employees.
See also
Australia Post
Postage stamps and postal history of Papua New Guinea
References
Postal systems
Postal infrastructure
Universal Postal Union
Companies of Papua New Guinea | Post PNG | [
"Technology"
] | 75 | [
"Transport systems",
"Postal systems"
] |
59,795,090 | https://en.wikipedia.org/wiki/Jan%20Marco%20Leimeister | Jan Marco Leimeister (born April 7, 1974) is a German university professor for business information systems from Bietigheim-Bissingen. He is tenured professor of business information systems and director at the Institute of Information Management (IWI HSG). at the University of St. Gallen as well as head of the Department of Information Systems and director at the Research Center for Information System Design (ITeG) at the University of Kassel.
Role in the business information systems community
Leimeister took over several functions at research conferences in (Business) Information Systems. For instance, he performed the function of a Program Chair at the European Conference on Information Systems (ECIS) 2014, as Co-Conference Chair of the conference „Wirtschaftsinformatik“ (WI) 2017 in St. Gallen, or as a Program Chair at the International Conference on Information Systems (ICIS) 2019. He is furthermore a member of committees of various information systems A-journals, for example Associate Editor of the European Journal of Information Systems (EJIS), Senior Editor of the Journal of Information Technology (JIT), and member of the Editorial Board of the Journal of Management Information Systems (JMIS).
Awards and recognitions
In a ranking of the renowned German business magazine “Wirtschaftswoche” from 2019, Leimeister was ranked among 2,824 business researchers from Germany, Austria and Switzerland on number 4 with regard to the research publication performance in journals within the years 2014 to 2018 and on number 8 with regard to his whole life research publication performance so far.
On September 3, 2018, Leimeister consulted as renowned expert in the field of crowdsourcing and digital work the German Federal Government (including chancellor Angela Merkel) in the “future talk” at Meseberg Castle (near Berlin)
For his research performance, he has been furthermore awarded in 2010 with the TUM Research Excellence Award in the field of innovation and leadership. For his teaching performance, he was awarded in 2009 the 3. Hesse University Prize for Excellence in teaching. The Association for Information Systems (AIS), the leading international professional association in information systems, conferred him the AIS Award for Innovation in Teaching in 2016.
References
External links
Complete publication overview
1974 births
Living people
Academic staff of the University of St. Gallen
Academic staff of the University of Kassel
German business theorists
German expatriates in Switzerland
Information systems researchers
People from Bietigheim-Bissingen | Jan Marco Leimeister | [
"Technology"
] | 501 | [
"Information systems",
"Information systems researchers"
] |
59,795,552 | https://en.wikipedia.org/wiki/Janet%20Hering | Janet Gordon Hering (born 1958) is the former Director of the Swiss Federal Institute of Aquatic Science and Technology and Professor emeritus of Biogeochemistry at ETH Zurich and EPFL (École Polytechnique Fédérale de Lausanne). She works on the biogeochemical cycling of trace elements in water and the management of water infrastructure.
Hering was elected a member of the National Academy of Engineering in 2015 for contributions to understanding and practice of removal of inorganic contaminants from drinking water.
She serves on the review board for Science Magazine.
Early life
Hering grew up in New York City. She studied chemistry at Cornell University and graduated in 1979. She was a summer intern at Mobil. She joined Harvard University for her graduate studies, earning a master's in chemistry in 1981, and began graduate work in organic chemistry. Hering realized that she preferred environmental sciences and moved to Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution for her graduate studies. She completed her PhD thesis. "The Kinetics and Thermodynamics of Copper Complexation in Aquatic Systems" in 1988. Her supervisor, François Morel, described her research as "elegant work on the surprisingly slow kinetics of some reactions between trace metals and organic complexing agents in natural water". She described the aquatic chemistry associated with the preparation of Aquil, an artificial algal culture, and the coordination of transition metals in seawater. At MIT, Hering met Werner Stumm, who offered her a postdoctoral position at EAWAG.
Research and career
Hering joined the Swiss Federal Institute of Aquatic Science and Technology (EAWAG) as a research fellow. She coordinated several scientific exchanges and managed international conferences. She co-authored the textbook Principles and Applications of Aquatic Chemistry with François Morel in 1993. The book was described by David Sedlak as a “a masterpiece that has influenced the way in which water chemistry is taught".
Hering moved to the University of California, Los Angeles in 1991 and was named Associate Professor in 1995. Around that time, Arsenic in water supplies became a worldwide concern. The World Health Organization recommended a value of only 10 μg per litre; as it can cause skin disease and cancer. Hering joined the California Institute of Technology in 1996, where she worked until 2006. Her work was supported by the National Science Foundation. She looked at the oxidation of arsenic in the Los Angeles Aqueduct, in particular at Hot Creek. Hot Creek is a geothermal area, where arsenic occurs at high concentrations as it degases from magma. The oxidation state of arsenic impacts its toxicity and mobility, as well as how easily it can be removed with treatment. By monitoring the amount of arsenic at various positions downstream, Hering found that the concentration remained constant, but the oxidation state changed. Hering found that arsenic was being oxidized into Arsenic(V) by a biological agent known as a macrophyte. She monitored Owens Lake, which is once of the largest in California but has dried up since the Los Angeles Aqueduct was constructed. The dusty lake bed results in large (> 10 μm) particles of high arsenic content airborne dust that can travel far and be inhaled. Hering worked closely with the Los Angeles Department of Water and Power to mitigate the arsenic in their watershed. She has continued to study arsenic contamination of water and ways to remove arsenic from drinking water. She identified that it was possible to remove arsenic from water using coagulation with ferric oxide and alum. Complete removal of Arsenic(V) oxide could be achieved after doses of 5 mg/L Ferric oxide. She has also investigated reverse osmosis and nanofiltration membranes, as well as on manganite surfaces. She gave evidence to the United States Environmental Protection Agency Ad Hoc Subcommittee on Arsenic Research and served on the Science Advisory Board. She was elected to the National Academies of Sciences, Engineering, and Medicine in 2015.
In 2007, she returned to the ETH Zurich, where she was appointed Professor of Environmental Biogeochemistry, and became Director of EAWAG. At EAWAG Hering is responsible for a $48 million annual budget, 300 staff and 100 graduate students. She was the first woman to be made Director of a Swiss federal research institute. She was made a Professor of Environmental Chemistry at EPFL in 2010. Since her return to Switzerland, Hering has worked on water quality and management, as well as promoting collaboration between academics. She is an investigator of the National Science Foundation’s Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt). Hering has written about the need for more knowledge brokering and ways to use interdisciplinary science to address challenges in society. In particular, Hering has offered that if water research were synthesized, it would be possible to achieve the Sustainable Development Goals.
She was made an honorary fellow of IHE Delft Institute for Water Education in 2017 and a fellow of the Geochemical Society in 2018. She was awarded the Clarke Prize from the National Water Research Institute in 2018. She served as chairwoman of the ETH Zurich Women Professors forum.
References
American environmental scientists
Scientists from New York City
Academic staff of the École Polytechnique Fédérale de Lausanne
Academic staff of ETH Zurich
Cornell University alumni
Massachusetts Institute of Technology alumni
Harvard University alumni
California Institute of Technology faculty
University of California, Los Angeles faculty
1958 births
Living people | Janet Hering | [
"Environmental_science"
] | 1,101 | [
"American environmental scientists",
"Environmental scientists"
] |
59,797,213 | https://en.wikipedia.org/wiki/Haplotype%20block | In genetics, a haplotype block is a region of an organism's genome in which there is little evidence of a history of genetic recombination, and which contain only a small number of distinct haplotypes. According to the haplotype-block model, such blocks should show high levels of linkage disequilibrium and be separated from one another by numerous recombination events. The boundaries of haplotype blocks cannot be directly observed; they must instead be inferred indirectly through the use of algorithms. However, some evidence suggests that different algorithms for identifying haplotype blocks give very different results when used on the same data, though another study suggests that their results are generally consistent. The National Institutes of Health funded the HapMap project to catalog haplotype blocks throughout the human genome.
Definition
There are two main ways that the term "haplotype block" is defined: one based on whether a given genomic sequence displays higher linkage disequilibrium than a predetermined threshold, and one based on whether the sequence consists of a minimum number of single nucleotide polymorphisms (SNPs) that explain a majority of the common haplotypes in the sequence (or a lower-than-usual number of unique haplotypes). In 2001, Patil et al. proposed the following definition of the term: "Suppose we have a number of haplotypes consisting of a set of consecutive SNPs. A segment of consecutive SNPs is a block if at least α percent of haplotypes are represented more than once".
References
Genomics
Biology terminology | Haplotype block | [
"Biology"
] | 340 | [
"nan"
] |
54,942,000 | https://en.wikipedia.org/wiki/MAPK%20networks | Mitogen-activated protein kinase (MAPK) networks are the pathways and signaling of MAPK, which is a protein kinase that consists of amino acids serine and threonine. MAPK pathways have both a positive and negative regulation in plants. A positive regulation of MAPK networks is to help in assisting with stresses from the environment. A negative regulation of MAPK networks is pertaining to a high quantity of reactive oxygen species (ROS) in the plant.
MAPK networks
Mitogen-activated protein kinase (MAPK) networks can be found in eukaryotic cells. MAPK pathways in plants are known to regulate cell growth, cell development, cell death, and cell responses to environmental stimuli. Only a few of the MAPK mechanism components are known and have been studied. The components such as Arabidopsis MAPKKKs YODA, ANP2/ANP3, and MP3K6/MP3K7 functions in the development of the cell. MEKK1 and ANP1 function in the response to environmental stress. Unfortunately, only eight out of the twenty mitogen-activated protein kinases have been studied. The most commonly studied MAPKs are MPK3, MPK4, and MPK6, which are activated by a diversity of stimuli including abiotic stresses, pathogens, and oxidative stressors. MPK4 negatively regulates biotic stress signaling, while MPK3 and MPK6 function as positive mediators of defense responses. The plant has these positive and negative mediators allowing for normal plant growth and development, which has been proven true by the severely dwarfed phenotype of mpk4 and the embryo lethal phenotype of mpk3 and mpk6 mutants.
Positive regulation pathways in plants
Plants have many protection mechanisms to cope with stresses from the environment, which include ultraviolet light, cold or hot weather, windy days, and mechanical wounding. There are multiple pathways, but one pathway that plants have been able to develop is a self-defense mechanism by recognize pathogens through pathogen-associated molecular patterns (PAMPs) via cell surface-located pathogen-recognition receptors. These receptors induce intracellular signal pathways within the plant cells, while also resulting in PAMP-triggered immunity. Responses to PAMPs target broadly instead of specifically. This immunity requires downstream components via the MAPK cascade to activate the MAP kinases. The flagellin, a peptide of flg22, triggers a rapid and strong activation of MPK3, MPK4, and MPK6. MPK4 and MPK6 can be activated by harpin proteins. MPK3 and MPK6 are very similar proteins and have a function as regulators in abscission, stomatal development, signaling various abiotic stresses, and defense responses to certain pathogens. Experimentation has proposed that the MAPK module MEKK1-MKK4/MKK5-MPK3/MPK6 may be responsible for flg22 signal transmission. All of the proposed modules appear to be correct expect for MEKK1 because plants with mekk1 mutated have a compromised flg22-triggered activation of MPK4, yet they have normal activation of MPK3 and MPK6. Data has shown that MAPK cascade is composed of MKK4/MKK5 and MPK3/MPK6 in response to fungal pathogens. The observation shows that the activation of MPK3/MPK6 in conditional gain-of-function plants for MKK4/MKK5 or MEKK1/MKKKa is sufficient to induce camalexin, which is a major phytoalexin in Arabidopsis. The stomata are considered to be the entry point for pathogenic invaders because microbial invaders enter the plant at the stomata. A recent study has shown that MAPK cascades play a role in abiotic and biotic stress responses. The main pathways in stomatal development and dynamics are MPK3 and MPK6. During a drought, the stomata closes and is believed to be mediated by the phytohormone, abscisic acid, and involves MKK1, MPK3, and MPK6. Another way of closing the stomata is through a closing process that is called pathogen-induced, which is an innate response from the plant. Campestris (Xcc) excretes a chemical that reverts stomatal closure that was caused by bacteria and abscisic acid (ABA). Most stomata close in the presence of ABA, but some are unresponsive to bacteria. In Arabidopsis Xcc does not revert bacteria-induced or ABA-induced stomatal closure. Scientists are not certain if MAPK cascades are responsible for the signaling, so further investigation is needed for this.
Negative regulation
The identification of MEKK1-MKK1/2-MPK4 in pathogen signaling has been a tremendous finding. Mekk1, mkk1/mkk2 double and mpk4 mutations are dwarfed and acquire too much of reactive oxygen species. The mutations are considered to be from the enhancement of SA levels, which is partially reversed by bacterial SA hydrolase. Mekk1, mkk1/mkk2 double and mpk4 mutations have cell death occur spontaneously, pathogenesis-related genes and increased resistance to pathogens. MEKK1 appears to have deregulation pathways that are unknown and do not involve MKK1/MKK2 nor MPK4. MEKK1 interact with WRKY53, which is responsible for mekk1 genes set, and alter the activity of WRKY53 that is a short portion of MAPK signaling. Substrates of MPK4 are three proteins: WRKY33, WRKY25, and MKS1. Ternary MKS1-MPK4-WRKY33 complexes have been recognized by nuclear extracts. Recruitment of WRKY33 depends on the phosphorylation of MPK4. Once activated, MPK3 phosphorylates MKS1, which releases WRKY33 from the ternary complex. The free WRKY33 is believed to induce transcription on target genes., allowing for a negative regulation by MPK4. Pathogens have developed mechanisms that inactivate PAMP-induced signaling pathways through the MAPK networks. Andrea Pitzschke and her colleges claim “AvrPto and AvrPtoB interact with the FLS2 receptor and its co-receptor BAK1. AvrPtoB catalyzes the polyubiquitination and subsequent proteasome-dependent degradation of FLS2” (Pitzschke 3). AvrPto interacts with BAK1 and interrupts the binding of FLS2. Pseudomonas syringae have HopAI1, which is a phosphothreonin lyase, and dephosphorylates the threonine residue at the upstream MAPKKs. HopAI1 interacts with MPK3 and MPK6 allowing for flg22 activation to occur. In certain soil-borne pathogens that carry flagellin variants cannot be detected by FLS2, but there is still a triggered innate immune response. The immune response has been shown to be from the EF-Tu protein. Flg22, elf18, FLS2 and EFR have receptors that are in the same subfamily of LRR-RLKs, LRRXII. This means that elf18 and flg22 induce extracellular alkalization, rapid activation of MAPKs, and gene responses that are similar to each other. Although there appears to be an important relationship between MAPKs with EF-Tu-triggered defense, the evidence remains to be unclear. The reason for this unclear relationship is because of Agrobacterium tumefaciens, which infects into segments of plant DNA. EFR1 mutants do not recognize EF-Tu, but there is no research on MAPK activities and efr1. Initiation of defense signaling can be a positive effect to the plant pathogens because activating MPK3 in response to flg22 causes phosphorylation and translocation of virE2 interacting protein 1 (VIP1). VIP1 serves as a shuttle for the pathogenic T-DNA, but the induction of defense genes can occur as well. This allows for the spreading and cessation of the pathogen in the plant, but the pathogen can overcome the problem by attacking VIP1 for proteasome degradation by VirF, which is a virulence factor that encodes an F-box protein.
References
Signal transduction | MAPK networks | [
"Chemistry",
"Biology"
] | 1,785 | [
"Biochemistry",
"Neurochemistry",
"Signal transduction"
] |
54,943,204 | https://en.wikipedia.org/wiki/Journal%20of%20Mathematical%20Analysis%20and%20Applications | The Journal of Mathematical Analysis and Applications is an academic journal in mathematics, specializing in mathematical analysis and related topics in applied mathematics. It was founded in 1960 by Richard Bellman, as part of a series of new journals on areas of mathematics published by Academic Press, and is now published by Elsevier. For most years since 2003 it has been ranked by SCImago Journal Rank as among the top 25% of journals in its topic areas.
References
Elsevier academic journals
Mathematical analysis journals
Mathematical analysis
Applied mathematics journals | Journal of Mathematical Analysis and Applications | [
"Mathematics"
] | 103 | [
"Mathematical analysis",
"Mathematical analysis stubs",
"Applied mathematics",
"Applied mathematics journals",
"Mathematical analysis journals"
] |
54,944,891 | https://en.wikipedia.org/wiki/LP%2040-365 | LP 40-365 is a low-mass white dwarf star in the constellation Ursa Minor. It travels at high speed through the Milky Way and has a very unusual elemental composition, lacking hydrogen, helium or carbon. It may have been produced in a subluminous Type Iax supernova that failed to destroy its host star totally.
The "LP" name is derived from the Luyten-Palomar proper motion catalogue in which it appeared in the 1960s. Another catalog name for this star is "GD 492".
The star was cataloged as a Giclas object with the designation "GD 492" being assigned by Henry Giclas in 1970.
References
External links
ESO Online Digitized Sky Survey
White dwarfs
Ursa Minor
Runaway stars | LP 40-365 | [
"Astronomy"
] | 157 | [
"Ursa Minor",
"Constellations"
] |
54,945,225 | https://en.wikipedia.org/wiki/Perenniporia%20minor | Perenniporia minor is a poroid fungus in the family Polyporaceae. It was described as a new species in 2008 by mycologists Yu-Cheng Dai and Hong-Xia Xiong. The type specimen was collected in Changbaishan Nature Reserve in Jilin province, where it was found growing on fallen angiosperm branches at an altitude of .
More than 20 species of genus Perenniporia have been found in China. Compared to other species of genus Perenniporia, P. minor has tiny fruit bodies with caps measuring up to wide and thick. It is this feature to which the specific epithet minor refers. The colour of the cap surface is initially pale buff, darkening slightly with age. The pores on the undersurface of the cap and tiny and round, numbering 4–6 per millimetre. Microscopically, the fungus is characterized by the almost negative reaction of the skeletal hyphae to Melzer's reagent.
References
Perenniporia
Fungi described in 2008
Fungi of China
Taxa named by Yu-Cheng Dai
Fungus species | Perenniporia minor | [
"Biology"
] | 222 | [
"Fungi",
"Fungus species"
] |
54,948,509 | https://en.wikipedia.org/wiki/Electromagnetic%20vortex%20intensifier%20with%20ferromagnetic%20particles | Electromagnetic vortex intensifier with ferromagnetic particles (vortex layer device, electromagnetic mill) consists of an operating chamber (pipeline) with a diameter of 60–330 mm, located inside an inductor with a rotating electromagnetic field. The operating chamber contains cylindrical ferromagnetic particles 0.5–5 mm in diameter and 5–60 mm in length, ranging from tens to several thousand pieces (0.05–20 kg), depending on the dimensions of the operating chamber of the intensifier.
History of electromagnetic vortex intensification
Electromagnetic devices with a vortex layer were proposed in 1967 by D.D. Logvinenko and O.P. Shelyakov. The monograph "intensification of technological processes on devices with a vortex layer", written by these authors, showed the effective use of these devices in:
mixing of liquids and gases
mixing of loose materials
dry grinding of solids (micro-resin)
grinding and dispersion of solids in liquid media
activation of substance surface
implementation of chemical reactions
changes in the physical and chemical properties of substances
Following this research, these intensifiers found their application in many researches and developments.
Physical processes in electromagnetic vortex intensifiers
Intensification of technological processes and chemical reactions is achieved due to intensive mixing and dispersion, acoustic and electromagnetic treatment, high local pressure and electrolysis of processed components. Electromagnetic devices with a vortex layer with ferromagnetic elements accelerate the reactions 1.5-2 times; reduce the consumption of reagents and electricity by 20%. The grinding effect is achieved by the motion of ferromagnetic particles and their free collision with each other, and a constrained collision between the particles and a body. The degree of grinding is 0.5 μm (with an initial size of 20 mm).
At present, the electromagnetic devices with a vortex layer with ferromagnetic elements actually exist (D.D. Logvinenko himself designed and produced more than 2000 pieces), their principle is also implemented in some technological lines.
Industrial application of electromagnetic vortex intensifiers
Examples of industrial applications of these devices for intensifying processes are:
preparation of food emulsions
preparation of multicomponent suspensions with vulcanizing and gelling agents (sulfur, zinc oxide, soot, kaolin, sodium silicofluoride) in latex sponge production; Obtaining suspensions of titanium dioxide used as matting agent for chemical fibers
wastewater treatment from acids, alkalis, hexavalent chromium compounds, nickel, iron, zinc, copper, cadmium, other heavy metals, cyanide compounds, and other contaminants
production of greases and emulsions
drilling fluid preparation
preparation of kerosene in water emulsions, silicone, rubber, latex, etc.
Electromagnetic vortex intensifier grinds and regrinds coal, alumina-containing slag, quartz sand, technical diamonds, cellulose, chalk, wood flour, fluoroplastics, etc.
Also, it can be used for decontamination of agricultural animal waste.
Issues of electromechanics and device design
The main parameters that characterize the rotating magnetic field created by a three-phase inductor in the working area of the apparatus in the absence of ferromagnetic particles include: the number of pairs of magnetic poles, the angular speed of their rotation; magnitude and speed of rotation of the magnetic induction vector hodograph, which in real devices is an ellipse with eccentricity increasing when approaching the surface of the working chamber. It is advisable to characterize the magnetic properties of the vortex layer by volume-averaged values; a convenient parameter for energy control of the operation of the vortex layer is its power density.
Devices AVS-100, АVS-150, etc. (Russian Cyrillic acronym: ) are focused on uniform distribution of ferromagnetic particles throughout the working area and have a bipolar inductor. When developing an inductor for these devices, the salient-pole design of liquid steel induction rotators was chosen as an analogue. The choice of salient-pole inductor design was associated mainly with simplified manufacturing technology, ease of operation, repair and cooling.
In the central part of the working area of these devices, the magnetic field in the absence of ferromagnetic particles is close to uniform: the hodograph of the magnetic induction vector in this area is close to a circle, coinciding with it in the center of the working area of these devices; the modulus of the magnetic induction vector is approximately 0.12 T (in various devices from 0.1 to 0.15 T); the angular speed of its rotation is 314 radians per second, which corresponds to a rotation speed of 3000 rpm.
In a working vortex layer, the modulus of the averaged magnetic induction vector reaches values of 0.2 T and lags behind the external field strength by a certain phase angle.
The specific power of the vortex layer in various modes for these devices ranges from 0.1 to 1.5 kW per cubic decimeter of the working area.
The devices have dual-circuit oil-water cooling, power capacitors to compensate for the reactive power of the inductor and are powered from a 380V, 50 Hz network. Other design features of the devices are described in detail in the monograph.
Subsequently, the design of these and similar devices was mastered, modified and expanded by other manufacturers and developers. Currently, devices use both salient-pole inductors and inductors with distributed windings, similar to the stators of electric motors; different types of cooling and power capacitors are used. If necessary, the device includes power converters of voltage and frequency from the supply network. Methods for monitoring and controlling the operation of the vortex layer and technological lines based on it are also being improved.
In scientific and technical developments related to issues of the electromechanics of devices of the class under consideration, computer modelling of the inductor and behavior of ferromagnetic particles is sometimes used. An analytical model of the force effect of a circular rotating magnetic field on a magnetic particle in devices with an external electric inductor with a different number of magnetic poles is considered in the work.
Recently, a method has been proposed and examples of rapid engineering evaluation calculation and analysis of the characteristics of the working rotating magnetic field of various cylindrical inductors with a longitudinal winding have been given
References
Electromagnetic components
Electrochemical engineering
Fluid dynamics
Fluid technology
Ferromagnetism
Drilling fluid
Electrolysis
Chemical reactions | Electromagnetic vortex intensifier with ferromagnetic particles | [
"Chemistry",
"Materials_science",
"Engineering"
] | 1,349 | [
"Chemical engineering",
"Electrochemical engineering",
"Fluid technology",
"Magnetic ordering",
"Electrochemistry",
"Ferromagnetism",
"Mechanical engineering by discipline",
"nan",
"Electrolysis",
"Piping",
"Electrical engineering",
"Fluid dynamics"
] |
54,949,641 | https://en.wikipedia.org/wiki/P%C3%A9ter%20Surj%C3%A1n | Péter R. Surján (born August 30, 1955) is a Hungarian theoretical chemist who is known for his research on application of the theory of second quantization in quantum chemistry.
In 2016 a festschrift from Theoretical Chemistry Accounts journal was published in his name which is also published as a book in Highlights in Theoretical Chemistry series by the Springer Nature. He is currently a professor and a former dean of the Faculty of Science of the Eötvös Loránd University.
Academic career
Surján received his Master's degree in physics in 1978 and his PhD in quantum chemistry in 1981, both from (Eötvös Loránd University. In 1986, he was a Candidate of Science. From there, he worked at the Technical University of Budapest as a senior researcher in physics from 1990 to 1995 before moving to Eötvös Loránd University, where he has been since. He has taught in the Department of Theoretical Chemistry since 1991, becoming a full professor in 1998, and has been the Director of the Bolyai College (2007-2012) and the Institute of Chemistry (2008-2012). He was also the dean of the Faculty of Science.
Surján is a member of the Hungarian Academy of Sciences (1998) and has been on the editorial boards of the Journal of Mathematical Chemistry and Interdisciplinary Sciences: Computational Life Sciences. He has also been a guest editor for the International Journal of Quantum Chemistry. Surján has published more than 190 papers in his scientific career. His first paper was published in 1980.
Selected publications
Papers
"Optical Rotatory Strength Calculation by Evaluating the Gradient Matrix through the Equation of Motion", Theoretica Chimica Acta 55, 103 (1980);
"Higher excitations in coupled-cluster theory", The Journal of Chemical Physics 115, 2945 (2001);
"A general state-selective multireference coupled-cluster algorithm", The Journal of Chemical Physics 117, 980 (2002);
"Computing coupled-cluster wave functions with arbitrary excitations", The Journal of Chemical Physics 113, 1359 (2000);
"An observable-based interpretation of electronic wavefunctions: application to “hypervalent” molecules", Computational and Theoretical Chemistry 255, 9 (1992);
Books
References
External links
1955 births
Living people
Hungarian chemists
Theoretical chemists
Eötvös Loránd University alumni
Academic staff of Eötvös Loránd University | Péter Surján | [
"Chemistry"
] | 484 | [
"Theoretical chemistry",
"Quantum chemistry",
"Physical chemists",
"Theoretical chemists"
] |
54,952,764 | https://en.wikipedia.org/wiki/Manh%C3%A8s%E2%80%93David%20process | The Manhès–David process is a refining process of the copper mattes, invented in 1880 by the French industrialist Pierre Manhès and his engineer . Inspired by the Bessemer process, it consists of the use of a converter to oxidise with air the undesirable chemical elements (mainly iron and sulfur) contained in the matte, to transform it into copper.
The quantity of the elements to be oxidized, as well as the low heat produced by the chemical reactions, lead to drastics modifications of the converter. Manhès and David designed it as a horizontal cylinder, with nozzles aligned from one end to the other. A few years later, the Americans engineers William H. Peirce and Elias Anton Cappelen Smith lined it with basic refractory materials, much more durable than that used by the French inventors. While this improvement does not alter the principles of the process, it eases its widespread use, accelerating the switchover of copper production from Britain to the United States.
At the beginning of the 21st century, the refine 90% of the copper mattes and is used in 60% of the nickel extracted. This converter, like the addition of pure oxygen, the automation of the running, the treatment of smoke and the increasing size of the tools, ensured the durability of the Manhès–David process, even if modern tools have little relationship with their ancestors.
Origins of the process
Relationship with the Bessemer process
Just as iron produced by a blast furnace comes out alloyed with other chemical elements as cast iron, copper extracted from ore becomes an alloy with sulfur, iron, etc. called matte. To apply the same purification processes to these two metals is therefore logical. Applying the Bessemer process to copper metallurgy was proposed, and the principle validated in 1866, ten years after Henry Bessemer's invention, by the Russian engineer Semenikow.
The refinement of the alloy in the converter is possible because the combustion of undesirable elements is strongly exothermic: the oxidation of silicon and carbon respectively produce 32.8 and 10.3 kilojoules per kilogram. On the other hand, if a copper matte contains an abundance of iron and sulfur, these elements must first be separated (which consumes 6.8 kilojoules per kilogram of FeS) before their oxidation (which only produces 5.9 and 9.1 kJ/kg respectively) can begin.
First attempts
The first refinements of copper alloys by a converter took place in Ducktown, Tennessee where A. Raht worked on a partial refinement of the matte from 1866 to 1875. In 1867, the Russians Jossa and Latelin tried to experimentally verify the studies of Semenikow. In 1870, they stopped their experiments after only having succeeded to increase the copper content from 31% to 72-80%.
In England, John Hollway continued these trials until 1878. Like his predecessors, he observed that if blowing began in a satisfactory manner, it became more and more intermittent as the refinement progressed. The obstacles he encountered were numerous:
The weight of produced slag was equal to that of copper and its volume was much greater than that in the converter. It was thus necessary to drain the retort regularly.
The density of the molten metal changed greatly (with copper having a density three times as great as the pyrite from which it is made).
The duration of the air blowing, which can reach two hours, involved large thermal losses.
The siliceous refractory material was absorbed by the slag, in which it acted as flux.
All of the encountered difficulties could not be easily resolved: the thermal heat balance of the refinement reaction in air of copper was not as favorable as for iron, and the matte solidified in the tuyeres before being refined. Even when modified, a Bessemer converter was capable at best of removing iron and a portion of sulfur. Hollway failed, but by publishing all of the details of his experiments, he identified the essential problems.
Lateral tuyeres
In the 1870s, the French industrialist Pierre Manhès began his first attempts with a small, ordinary Bessemer converter of 50 kg in his factory in Vedène, then in factories in Éguilles, near Avignon. He sought to refine a matte with 25 to 30% copper previously melted in a crucible. But like Hollway, he did not succeed in completely refining the matte. The oxidation of undesirable elements occurred as expected, but the operation was quickly disrupted by the appearance of metallic copper. The matte, which was an ionic compound, was immiscible with the slag, but also with the molten metal. The latter, which is denser (ρcopper ≈ 9), went to the bottom of the converter and clogged the tuyeres.
Pierre Manhès then patented the use of additives whose oxidation would release enough heat to avoid getting stuck. In the end, it was the Frenchman Paul David, then an engineer in his factory in 1880, who suggested the solution. He proposed horizontal tuyeres placed at a sufficient distance from the bottom of the converter so that the copper could gather below them and the air blow constantly in the matte. By 1881, their converter was both technically operational and cost-effective.
In the autumn of 1884, the process was adopted in the United States by the Parrot Silver and Copper Company in Butte, Montana. The two types became larger and larger, increasing from a capacity of one ton to eight tons in 1912, and even fifteen tons for cylindrical converters in 1920.
Improvement by Peirce and Smith
As the slag becomes enriched with iron oxide during the reaction in air, it becomes basic and then combines with the siliceous refractory lining, which is very acidic. A basic refractory lining would not react and would therefore lower the cost of production. The adoption of a lining inspired by one developed by Sidney Thomas and Percy Gilchrist in 1877 was suggested by Hollway during his last tests in the early 1800s. However, the idea was not tested, as fundamental problems related to the air blowing were more of a problem than refractory optimization.
In 1890, a basic refractory lining was tested on one of Parrot Smelter's Manhès-David converters, in Butte, under the direction of Herman A. Keller. The tests did not result in a lining compatible with industrial operation. In 1906, Ralph Baggaley, still in Montana, succeeded, after a number of tests, in industrializing a basic coating at Pittsmont Smelter, which was abandoned in 1908 after he left the factory. After all that, the Norwegian Kudsen succeeded as of 1908 in using a basic coating with the Sulitjelma Mines. He carried out two successive blowings there, initially in a small converter with a basic coating, and then in a second traditional converter with an acidic coating.
Finally, in 1909, at the Baltimore Copper Company's Smelter, the Americans William H. Peirce and Elias A.C. Smith succeeded in addressing the main drawbacks of basic refractories; basic refractories were more fragile, and, above all, they dissipated more heat than acidic refractories. By developing a masonry suitable for the cylindrical converter and increasing the amount of metal fed into the furnace, they solved the remaining problems.
Peirce and Smith's converter proved much more advantageous than that of Manhès and David. The basic refractory, which did not react with slag, lasted much longer. This improvement eliminated the need for replacement of the converters, the construction of masonry installations, and replacement converters (there were two masonry converters for every one in service in 1897 at Anaconda Copper). It also reduced the risk of piercings due to poor control of wearing of the refractory. The refractory layer could then be thinner, increasing the capacity of the converter. The capacity was not dependent on wearing of the refractory, thus simplifying the management of the flows of molten metal in factories.
If the material used to prepare the acid refractory contains copper, or even silver or gold (frequently associated with copper in gold-bearing quartz), these metals join the matte as the lining is removed. Considering the refractory's rapid destruction, the economic advantage of an acidic refractory is therefore only realized if its consumption adds value to the process. This situation is however rather rare and, even if this is the case, silica rich in precious metals can be made by other economically viable means. Therefore, in 1921, the basic refractory was considered the main factor in the cost reduction in the extraction of copper ores. In some cases, a reduction in conversion costs from $15–20 to $4–5 was reported.
Converting in copper metallurgy
A mixture of copper and iron sulfides referred to as matte is treated in converters to oxidize iron in the first stage, and oxidize copper in the second stage. In the first stage oxygen enriched air is blown through the tuyeres to partially convert metal sulfides to oxides:
FeS + O2 → FeO + SO2
CuS + O2 → CuO + SO2
Since iron has greater affinity to oxygen, the produced copper oxide reacts with the remaining iron sulfide:
CuO + FeS → CuS + FeO
The bulk of the copper oxide is turned back into the form of sulfide. In order to separate the obtained iron oxide, flux (mainly silica) is added into the converter. Silica reacts with iron oxide to produce a light slag phase, which is poured off through the hood when the converter is tilted around the rotation axis:
2 FeO + SiO2 → Fe2SiO4 (sometimes denoted as 2FeO•SiO2, fayalite)
After the first portion of slag is poured off the converter, a new portion of matte is added, and the converting operation is repeated many times until the converter is filled with the purified copper sulfide. The converter slag is usually recycled to the smelting stage due to the high content of copper in this by-product. Converter gas contains more than 10% of sulfur dioxide, which is usually captured for the production of sulfuric acid.
The second stage of converting is aimed at oxidizing the copper sulfide phase (purified in the first stage), and produces blister copper. The following reaction takes place in the converter:
CuS + O2 → Cu + SO2
Copper content in the obtained blister copper is typically more than 95%. Blister copper is the final product of converting.
References
Metallurgical processes | Manhès–David process | [
"Chemistry",
"Materials_science"
] | 2,255 | [
"Copper processes",
"Metallurgical processes",
"Metallurgy"
] |
54,953,273 | https://en.wikipedia.org/wiki/Phlebia%20coccineofulva | Phlebia coccineofulva, commonly known as the scarlet waxcrust, is a species of crust fungus in the family Meruliaceae. It was described as a new species by Lewis David de Schweinitz in 1832. The fungus is found in North America, continental Europe, and northern Asia, where it grows as a saprophyte on decaying stumps and woody forest debris.
References
Fungi described in 1832
Fungi of Asia
Fungi of Europe
Fungi of North America
Meruliaceae
Fungus species | Phlebia coccineofulva | [
"Biology"
] | 105 | [
"Fungi",
"Fungus species"
] |
54,953,515 | https://en.wikipedia.org/wiki/SAML%20metadata | The SAML metadata standard belongs to the family of XML-based standards known as the Security Assertion Markup Language (SAML) published by OASIS in 2005. A SAML metadata document describes a SAML deployment such as a SAML identity provider or a SAML service provider. Deployments share metadata to establish a baseline of trust and interoperability.
Overview
To securely interoperate, partners share metadata in whatever form and by whatever means possible. In any case, at least the following metadata must be shared:
Entity ID
Protocol endpoints (bindings and locations)
Every SAML system entity has an entity ID, a globally-unique identifier used in software configurations, relying-party databases, and client-side cookies. On the wire, every SAML protocol message contains the entity ID of the issuer.
For authentication purposes, a SAML message may be digitally signed by the issuer. To verify the signature on the message, the message receiver uses a public key known to belong to the issuer. Similarly, to encrypt a message, a public encryption key belonging to the ultimate receiver must be known to the issuer. In both situations—signing and encryption—trusted public keys must be shared in advance.
Once the message is signed and encrypted, the issuer sends the message to a trusted protocol endpoint, the location of which must be known in advance. Upon receipt, the message receiver decrypts the message (using its own private decryption key) and verifies the signature (using a trusted public key in metadata) before mapping the entity ID in the message to a trusted partner.
The previous scenario requires each party to know the other in advance. To establish a baseline of trust, parties share metadata with each other. Initially, this may be as simple as sharing information via email. Over time, as the number of SAML partners grows, the natural tendency is to automate the metadata sharing process.
To fully automate the metadata sharing process, a standard file format is needed. To this end, the SAML V2.0 Metadata specification defines a standard representation for SAML metadata that simplifies the configuration of SAML software and makes it possible to create secure, automated processes for metadata sharing.
Metadata-driven interoperability
As SAML technology has matured, the importance of SAML metadata has steadily increased. Today an implementation that supports SAML web browser requires a schema-valid SAML metadata file for each SAML partner. (See the SAML V2.0 Profiles specification for more information about SAML web browser SSO.)
Static metadata configuration
The term static metadata refers to a metadata file that is configured directly into the SAML application by an administrator. In doing so, the administrator becomes responsible for the maintenance of the metadata regardless of how the metadata was obtained in the first place. Thus static metadata contributes to the overall static configuration of the SAML application.
Unfortunately, SAML metadata is inherently non-static as illustrated by the following typical scenario between a SAML identity provider (IdP) and a SAML service provider (SP). Suppose an IdP owner obtains SAML metadata from an SP partner. Perhaps the SP metadata is transmitted to the IdP owner via email, or maybe the IdP owner logs into a protected web app and downloads the SP metadata via a browser. Regardless of how the metadata is obtained, the result is the same: the IdP owner configures the SP metadata directly into the IdP software.
Now suppose the SP metadata contains a public encryption key. Presumably, the corresponding private decryption key is configured into the SP software. If the private decryption key is compromised (or otherwise needs to be replaced), the public encryption key in the SP metadata is no longer trustworthy and must be replaced as well.
Since the SP metadata is statically configured in the IdP software, only the IdP owner can replace the public encryption key in the SP metadata. In this sense, the IdP owner is responsible for the SP metadata. This mismatch leads to interoperability issues.
The same is true on the SP side. By statically configuring IdP metadata into the SP software, the SP owner implicitly accepts the responsibility to maintain the IdP metadata when something changes. Since an IdP (or SP) typically has many partners, static metadata configuration clearly does not scale, and moreover, change management associated with static metadata is difficult at best.
Dynamic metadata exchange
Not surprisingly, metadata sharing processes yearn to be automated. Every metadata file that is statically configured into the SAML application by an administrator incurs technical debt. The accumulation of this debt prevents the SAML deployment from scaling to its potential.
To avoid excessive technical debt, the metadata sharing process must be automated. One approach is to enlist the help of a trusted third party whose responsibility it is to collect, curate, and distribute metadata across the network. Curated metadata is consistently formatted, more likely to be free of vulnerabilities (intentional or otherwise), and therefore safe to use.
In the case of SAML metadata, this trusted third party is called a SAML federation. The community of SAML deployers comprising the federation willingly conform to one or more profiles of SAML to promote interoperability and trust. To that end, federation participants often share a central infrastructure for metadata sharing, which allows the federation to scale to thousands of interoperable SAML deployments.
History
Now let's retrace some of the steps that led to the publication of the SAML V2.0 Metadata specification in March 2005. A turning point occurred on 14 November 2003—our story starts there.
Historical origins
In response to Microsoft Passport, the Liberty Alliance conceived the Identity Federation Framework, a federation technology developed over a three-year period between 2002 and 2004. (The previously mentioned history of SAML provides context for ID-FF.) On 14 November 2003, Liberty contributed ID-FF 1.2 to OASIS. The contribution included a document entitled Liberty Metadata Description and Discovery Specification Version 1.0, which included the following design goals:
"whois for SAML federations" (based on the Organization and ContactPerson elements in metadata)
dynamic discovery of metadata (with resolution via DNS and Well-Known Location)
document-level security using XML Signature
As it turns out, all of those goals were preserved in the OASIS SAML V2.0 Metadata Standard described later in this article.
The schema document included with the legacy Liberty ID-FF 1.2 archive is identified as Liberty Metadata Version 1.1 whereas Liberty Metadata Version 1.0 was contributed to OASIS. The apparent contradiction was explained by the schema's author. (Peter Davis, Personal Communication) Between November 2003 (when Version 1.0 was contributed to OASIS) and December 2004 (when Version 1.1 was completed by Liberty), development of the Liberty metadata specification continued in parallel with the OASIS work stream. See the chart below for a visual representation. The arrows in the chart indicate dependencies while the dashed lines indicate equivalencies.
Relevant references into the Liberty work stream are given at the end of this article. The original metadata schema contributed to OASIS is listed in its entirety in section 7 of the Liberty Metadata Version 1.0 specification. Similarly, the specification for Liberty Metadata Version 1.1 includes a listing of the Version 1.1 schema. Both the Version 1.0 schema and the Version 1.1 schema are linked here courtesy of the Internet Archive's Wayback Machine.
Post-November 2003
Over the next thirteen months, from November 2003 to December 2004, the OASIS Security Services (SAML) Technical Committee (SSTC) molded the Liberty metadata specification into what eventually became known as SAML Metadata. During that time, the SSTC generalized the metadata specification to include support for multiple protocols (including non-SAML protocols) but more importantly, the Liberty metadata schema was retrofitted with numerous extension points. Historically, the extensibility of SAML Metadata has had important consequences, as we shall see.
By March 2004, most of the Liberty contribution was incorporated into the OASIS work stream. From that point onward, the Liberty and OASIS work streams progressed concurrently (but not independently since the same people were working on both specifications). Between March and July 2004, the fledgling SAML Metadata specification underwent significant churn.
In July 2004, the SSTC issued a public call for comments covering a complete set of SAML V2.0 draft specifications. Included in that specification set was a working draft of a newly forged SAML V2.0 Metadata specification.
In retrospect, it appears as though the bulk of the SAML V2.0 Metadata specification was developed between March and July 2004, but clearly the SAML V2.0 Metadata Standard sprung from the loins of the Liberty Alliance, specifically Liberty Metadata Version 1.0. Consequently, to understand the origins of SAML Metadata, one must study the provenance of Liberty metadata.
The remaining history of SAML Metadata is mostly OASIS administrative process. After the final Committee Draft was published in November 2004, the SSTC began the standardization process in January 2005. Finally, on 5 March 2005, OASIS announced the newly ratified SAML V2.0 Standard.
The V2.0 specification set (see the References section for a complete list) included the final SAML V2.0 Metadata specification. A decade later, in September 2015, OASIS published a revised SAML Metadata specification with errata. As a result, the original metadata specification was deprecated, as were the other documents in the original 2.0 specification set.
During the intervening decade, between 2005 and 2015, the SSTC developed a number of "Post-V2.0" draft specifications. Some of these draft documents became Committee Specifications. A select subset of these Committee Specifications are listed in the References section at the end of this article.
Pre-November 2003
As it turns out, the influence of the Liberty Identity Federation Framework on SAML Metadata predates the contribution of ID-FF 1.2 in November 2003. Apparently the SSTC was dabbling in metadata in parallel with the Liberty Alliance. An excerpt from a draft metadata specification published in September 2003 bears this out:
This document defines metadata that describe the elements and attributes required to use the SAML Web Browser SSO Profiles. Since the Liberty Alliance Web SSO Profiles are directly based on the SAML Web SSO Profiles, the metadata defined in this document borrows extensively from the metadata definitions in the draft Liberty Alliance 1.2 specifications. (Excerpted from "Metadata for SAML 2.0 Web Browser SSO Profiles")
The revision history at the end of that draft document gives the following characterization of itself: "Initial draft based on Draft 07 of SAML 1.1 Metadata specification." In other words, earlier draft documents were published. Indeed, the revision history at the end of the previous draft shows a trail of metadata specifications dating back to November 2002.
Following the document trail, the influence of Liberty ID-FF on SAML metadata can be traced to a draft specification published in April 2003. This is the first known OASIS document that references Liberty ID-FF, specifically, Liberty Metadata Version 1.0-06, an early version of the Liberty Metadata specification about which little is known. It is, however, clear that "Metadata for SAML 1.1 Web Browser Profiles" was intended to be a companion to the SAML V1.1 Standard but of course we know that V1.1 does not specify the use of metadata. See the next section for relevant conjecture.
Two early metadata schema may be of interest:
In June 2002, barely a month after the SSTC completed its work on what was to become the SAML V1.0 Standard, the Shibboleth project developed a metadata schema consisting of <OriginSite> and <DestinationSite> elements. This schema would drive the initial versions of the Shibboleth IdP software.
In February 2003, the SSTC released a draft schema for a metadata specification entitled "Metadata for SAML 1.0 Web Browser Profiles." That schema remains a curiosity, however, since the very next version of that document stream (and all subsequent versions) would exhibit the Liberty metadata syntax.
There is no evidence to suggest that either of these early attempts to define a metadata schema had any appreciable effect on the development of the Liberty metadata schema.
Historical summary
We know that metadata standards for SAML V1.0 or SAML V1.1 were never published. We also know that the necessary IPR for Liberty Metadata was not in place until November 2003. With that, we offer the following summary and conjecture:
A draft specification entitled "Metadata for SAML 1.0 Web Browser Profiles" was the first known SAML metadata specification. The document is dated 12 November 2002, which is one week after the SAML V1.0 Standard was announced, which is curious. In any case, the metadata syntax used in that document is completely different from what we now know as SAML Metadata. That document was never published and its origins remain a mystery.
A draft specification entitled "Metadata for SAML 1.1 Web Browser Profiles" was the first known SAML metadata specification based on Liberty ID-FF. It was completed in April 2003. The title of the draft specification makes it clear that the SSTC knew that SAML V1.1 was coming and moreover SAML metadata was to be included in the SAML V1.1 Standard.
Unfortunately that did not happen since the necessary IPR was not in place when the SAML V1.1 Standard was announced. Indeed, the formal contribution of Liberty ID-FF 1.2 to OASIS occurred two months after the announcement of the SAML V1.1 Standard in September 2003.
In September 2003, less than two weeks after the announcement of the SAML V1.1 Standard, the SSTC set its sights on SAML V2.0 by forking the document stream and renaming the draft document: "Metadata for SAML 2.0 Web Browser Profiles."
SAML Metadata came to life between March and July 2004. The SSTC issued a public call for comments that included a candidate SAML Metadata specification.
The final SAML Metadata specification was included in the SAML V2.0 Standard specification set announced in March 2005.
For the next 10 years, the specification documents evolved (but the schema remained stable). A specification for SAML V2.0 Metadata with Errata (SAMLMeta20Errata) was published in September 2015.
Post-V2.0 specifications
As mentioned earlier, the SAML V2.0 Metadata Schema has numerous extension points. This feature led to a proliferation of "Post-V2.0" specifications that extended the standard in several directions. The more popular metadata extensions are listed below for convenience (see the examples for specific use cases):
SAML V2.0 Metadata Extensions for Registration and Publication Information Version 1.0.
SAML V2.0 Metadata Extension for Entity Attributes.
SAML V2.0 Metadata Extensions for Login and Discovery User Interface Version 1.0.
Identity Provider Discovery Service Protocol and Profile.
Service Provider Request Initiation Protocol and Profile Version 1.0.
SAML V2.0 Metadata Profile for Algorithm Support Version 1.0.
An important "Post-V2.0" specification is the SAML V2.0 Metadata Interoperability Profile, which builds on the premise that a formal public key infrastructure (PKI) can be extremely complex and in some cases intractable (it is well known, for example, that browser-facing TLS certificate revocation is broken). In essence, the Metadata Interoperability Profile is an attempt to provide a workable key revocation mechanism for SAML federations.
Since its publication in August 2009, the Metadata Interoperability Profile has been a particularly influential document, especially in higher education (see, for example, the certificate-related requirements for deployers in one large R&E federation). Metadata interoperability plays a key role in a formal implementation profile published by the Kantara Initiative:
Indeed, the key feature that distinguishes a scalable SAML implementation (from one that is not) is metadata interoperability.
SAML metadata examples
In this section we give concrete examples of the SAML entity descriptor, the basic unit of policy and interoperability in SAML metadata. Each of the examples includes the following metadata bits:
Entity ID and entity attributes
Role descriptor (describing either a SAML identity provider or a SAML service provider)
User interface elements
Signing keys or encryption keys
Single sign-on protocol endpoints
Registration and publication info
Organization and contact info (for human readers)
In the examples below, a particular URI in metadata (such as an entityID or an endpoint location) maps to a responsible party via the URI's domain component:
The organization that owns domain example.info is responsible for an unspecified SAML entity (such as an identity provider or a service provider)
The organization that owns domain example.org is responsible for a SAML identity provider
The organization that owns domain example.com is responsible for a SAML service provider
The organization that owns domain example.net is a trusted 3rd party responsible for metadata registration and publication
Note that SAML metadata describes all parties involved in metadata-driven SAML Web Browser SSO except the browser user. (See the SAML V2.0 Profiles specification for more information about SAML web browser SSO.)
Entity metadata
The following code sample illustrates the common technical features of a SAML <md:EntityDescriptor> element:
<md:EntityDescriptor entityID="https://sso.example.info/entity" validUntil="2017-08-30T19:10:29Z"
xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
xmlns:mdrpi="urn:oasis:names:tc:SAML:metadata:rpi"
xmlns:mdattr="urn:oasis:names:tc:SAML:metadata:attribute"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
<!-- insert ds:Signature element (omitted) -->
<md:Extensions>
<mdrpi:RegistrationInfo registrationAuthority="https://registrar.example.net"/>
<mdrpi:PublicationInfo creationInstant="2017-08-16T19:10:29Z" publisher="https://registrar.example.net"/>
<mdattr:EntityAttributes>
<saml:Attribute Name="http://registrar.example.net/entity-category" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
<saml:AttributeValue>https://registrar.example.net/category/self-certified</saml:AttributeValue>
</saml:Attribute>
</mdattr:EntityAttributes>
</md:Extensions>
<!-- insert one or more concrete instances of the md:RoleDescriptor abstract type (see below) -->
<md:Organization>
<md:OrganizationName xml:lang="en">...</md:OrganizationName>
<md:OrganizationDisplayName xml:lang="en">...</md:OrganizationDisplayName>
<md:OrganizationURL xml:lang="en">https://www.example.info/</md:OrganizationURL>
</md:Organization>
<md:ContactPerson contactType="technical">
<md:SurName>SAML Technical Support</md:SurName>
<md:EmailAddress>mailto:technical-support@example.info</md:EmailAddress>
</md:ContactPerson>
</md:EntityDescriptor>
Note the following details about this general entity descriptor:
The entityID attribute is the unique identifier of the entity. Note well that the entityID is an immutable name for the entity, not a location.
The validUntil attribute gives the expiration date of the metadata.
The <ds:Signature> element (which has been omitted for simplicity) contains a digital signature that ensures the authenticity and integrity of the metadata. The signatory is assumed to be a trusted 3rd party called a metadata registrar.
The <mdrpi:RegistrationInfo> extension element asserts an identifier for the metadata registrar.
The <mdrpi:PublicationInfo> extension element asserts the metadata publisher (which happens to be the same as the registrar). The creationInstant attribute gives the precise instant the metadata was created. Comparing the value of the creationInstant attribute to the value of the validUntil attribute, we see that the metadata is valid for two weeks.
The <mdattr:EntityAttributes> extension element includes a single entity attribute. The entity attribute claims that the entity is "self-certified," a presumably desirable quality.
The organization identified in the <md:Organization> element is "responsible for the entity" described by the entity descriptor (section 2.3.2 of SAMLMeta). The <md:Organization> element contains one or more language-qualified child elements of each type.
The contact information in the <md:ContactPerson> element identifies a technical contact responsible for the entity. Multiple contacts and contact types are possible. See section 2.3.2.2 of SAMLMeta.
The all-important role descriptor has been omitted from this initial example for brevity. The SAML metadata specification defines numerous concrete instances of the md:RoleDescriptor abstract type (section 2.4.1 of SAMLMeta). The two most important roles are described by the <md:IDPSSODescriptor> element and the <md:SPSSODescriptor> element. Each of these role descriptors is illustrated in the subsections below.
Identity provider metadata
A SAML identity provider manages a Single Sign-On Service endpoint that receives authentication requests from service providers. The entity descriptor for an identity provider in that role contains an <md:IDPSSODescriptor> element, which itself contains at least one <md:SingleSignOnService> endpoint. The following example illustrates two such endpoints:
<md:EntityDescriptor entityID="https://sso.example.org/idp" validUntil="2017-08-30T19:10:29Z"
xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
xmlns:mdrpi="urn:oasis:names:tc:SAML:metadata:rpi"
xmlns:mdattr="urn:oasis:names:tc:SAML:metadata:attribute"
xmlns:mdui="urn:oasis:names:tc:SAML:metadata:ui"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
<!-- insert ds:Signature element (omitted) -->
<md:Extensions>
<mdrpi:RegistrationInfo registrationAuthority="https://registrar.example.net"/>
<mdrpi:PublicationInfo creationInstant="2017-08-16T19:10:29Z" publisher="https://registrar.example.net"/>
<mdattr:EntityAttributes>
<saml:Attribute Name="http://registrar.example.net/entity-category" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
<saml:AttributeValue>https://registrar.example.net/category/self-certified</saml:AttributeValue>
</saml:Attribute>
</mdattr:EntityAttributes>
</md:Extensions>
<md:IDPSSODescriptor protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol">
<md:Extensions>
<mdui:UIInfo>
<mdui:DisplayName xml:lang="en">Example.org</mdui:DisplayName>
<mdui:Description xml:lang="en">The identity provider at Example.org</mdui:Description>
<mdui:Logo height="32" width="32" xml:lang="en">https://idp.example.org/myicon.png</mdui:Logo>
</mdui:UIInfo>
</md:Extensions>
<md:KeyDescriptor use="signing">
<ds:KeyInfo>...</ds:KeyInfo>
</md:KeyDescriptor>
<md:SingleSignOnService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect" Location="https://idp.example.org/SAML2/SSO/Redirect"/>
<md:SingleSignOnService Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Location="https://idp.example.org/SAML2/SSO/POST"/>
</md:IDPSSODescriptor>
<md:Organization>
<md:OrganizationName xml:lang="en">Example.org Non-Profit Org</md:OrganizationName>
<md:OrganizationDisplayName xml:lang="en">Example.org</md:OrganizationDisplayName>
<md:OrganizationURL xml:lang="en">https://www.example.org/</md:OrganizationURL>
</md:Organization>
<md:ContactPerson contactType="technical">
<md:SurName>SAML Technical Support</md:SurName>
<md:EmailAddress>mailto:technical-support@example.org</md:EmailAddress>
</md:ContactPerson>
</md:EntityDescriptor>
The content of the <md:IDPSSODescriptor> element describes the Single Sign-On Service at the identity provider. Note the following details about this element:
The <mdui:UIInfo> container contains a set of language-qualified extension elements used to build dynamic user interfaces at the service provider. The most important user interface at the service provider is the identity provider discovery interface.
The identity provider software is presumably configured with a private SAML signing key. The corresponding public key is included in the <md:KeyDescriptor use="signing"> element. In the above example, the key material has been omitted from the key descriptor for brevity.
The Binding attributes of the <md:SingleSignOnService> elements are standard URIs specified in the SAML 2.0 Binding specification (SAMLBind).
The values of the md:SingleSignOnService/@Location attributes in identity provider metadata are used by a service provider to route SAML messages, which minimizes the possibility of a rogue identity provider orchestrating a man-in-the-middle attack.
Service provider metadata
A SAML service provider manages an Assertion Consumer Service endpoint that receives authentication assertions from identity providers. The entity descriptor for a service provider in that role contains an <md:SPSSODescriptor> element, which itself contains at least one <md:AssertionConsumerService> endpoint. The following example illustrates such an endpoint:
<md:EntityDescriptor entityID="https://sso.example.com/portal" validUntil="2017-08-30T19:10:29Z"
xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
xmlns:mdrpi="urn:oasis:names:tc:SAML:metadata:rpi"
xmlns:mdattr="urn:oasis:names:tc:SAML:metadata:attribute"
xmlns:mdui="urn:oasis:names:tc:SAML:metadata:ui"
xmlns:idpdisc="urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
<!-- insert ds:Signature element (omitted) -->
<md:Extensions>
<mdrpi:RegistrationInfo registrationAuthority="https://registrar.example.net"/>
<mdrpi:PublicationInfo creationInstant="2017-08-16T19:10:29Z" publisher="https://registrar.example.net"/>
<mdattr:EntityAttributes>
<saml:Attribute Name="http://registrar.example.net/entity-category" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri">
<saml:AttributeValue>https://registrar.example.net/category/self-certified</saml:AttributeValue>
</saml:Attribute>
</mdattr:EntityAttributes>
</md:Extensions>
<md:SPSSODescriptor WantAssertionsSigned="true" protocolSupportEnumeration="urn:oasis:names:tc:SAML:2.0:protocol">
<md:Extensions>
<mdui:UIInfo>
<mdui:DisplayName xml:lang="en">Example.com Vendor Service</mdui:DisplayName>
<mdui:InformationURL xml:lang="en">https://service.example.com/about.html</mdui:InformationURL>
<mdui:PrivacyStatementURL xml:lang="en">https://service.example.com/privacy.html</mdui:PrivacyStatementURL>
<mdui:Logo height="32" width="32" xml:lang="en">https://service.example.com/myicon.png</mdui:Logo>
</mdui:UIInfo>
<idpdisc:DiscoveryResponse index="0" Binding="urn:oasis:names:tc:SAML:profiles:SSO:idp-discovery-protocol" Location="https://service.example.com/SAML2/Login"/>
</md:Extensions>
<md:KeyDescriptor use="encryption">
<ds:KeyInfo>...</ds:KeyInfo>
</md:KeyDescriptor>
<md:NameIDFormat>urn:oasis:names:tc:SAML:2.0:nameid-format:transient</md:NameIDFormat>
<md:AssertionConsumerService index="0" Binding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST" Location="https://service.example.com/SAML2/SSO/POST"/>
<md:AttributeConsumingService index="0">
<md:ServiceName xml:lang="en">Example.com Employee Portal</md:ServiceName>
<md:RequestedAttribute isRequired="true"
NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
Name="urn:oid:1.3.6.1.4.1.5923.1.1.1.13" FriendlyName="eduPersonUniqueId"/>
<md:RequestedAttribute
NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
Name="urn:oid:0.9.2342.19200300.100.1.3" FriendlyName="mail"/>
</md:AttributeConsumingService>
</md:SPSSODescriptor>
<md:Organization>
<md:OrganizationName xml:lang="en">Example.com Inc.</md:OrganizationName>
<md:OrganizationDisplayName xml:lang="en">Example.com</md:OrganizationDisplayName>
<md:OrganizationURL xml:lang="en">https://www.example.com/</md:OrganizationURL>
</md:Organization>
<md:ContactPerson contactType="technical">
<md:SurName>SAML Technical Support</md:SurName>
<md:EmailAddress>mailto:technical-support@example.com</md:EmailAddress>
</md:ContactPerson>
</md:EntityDescriptor>
The content of the <md:SPSSODescriptor> element describes the Assertion Consumer Service at the service provider. Note the following details about this element:
The WantAssertionsSigned attribute on the <md:SPSSODescriptor> element declares that the service provider wants the <saml:Assertion> element to be digitally signed. This attribute causes a metadata-aware identity provider to auto-configure itself at run time.
The <mdui:UIInfo> extension element contains a set of language-qualified extension elements used to build dynamic user interfaces at the identity provider. Two important user interfaces at the identity provider are the login page and the user consent interface.
The <idpdisc:DiscoveryResponse> extension element defines an endpoint used in conjunction with identity provider discovery.
The service provider software is presumably configured with a private SAML decryption key. A public SAML encryption key is included in the <md:KeyDescriptor use="encryption"> element. In the above example, the key material has been omitted from the key descriptor for brevity.
The <md:NameIDFormat> element gives the desired format of the <saml:NameID> element in the SAML assertion. The presence of this element causes a metadata-aware identity provider to auto-configure itself at run time.
The index attribute of an <md:AssertionConsumerService> element is used as the value of the AssertionConsumerServiceIndex attribute in a <samlp:AuthnRequest> element.
The Binding attribute of the <md:AssertionConsumerService> element is a standard URI specified in the SAML 2.0 Binding specification (SAMLBind).
The <md:AttributeConsumingService> element is used by the identity provider to formulate an <saml:AttributeStatement> element that is pushed to the service provider in conjunction with SAML Web Browser SSO.
The index attribute of the <md:AttributeConsumingService> element is used as the value of the AttributeConsumingServiceIndex attribute in a <samlp:AuthnRequest> element.
The value of the md:AssertionConsumerService/@Location attribute in service provider metadata is used by an identity provider to route SAML messages, which minimizes the possibility of a rogue service provider orchestrating a man-in-the-middle attack.
Metadata-driven SAML web browser
The following SAML protocol flow is intended to illustrate the use of metadata at various stages of SAML web browser SSO. (See the SAML V2.0 Profiles specification for more information about SAML web browser SSO.)
Trusted SAML metadata ensures a secure transaction between a SAML identity provider (IdP) and a SAML service provider (SP). Before metadata, trust information was encoded into the implementation in a proprietary manner. Now the sharing of trust information is facilitated by standard metadata. The SAML 2.0 Metadata Standard provides a well-defined, interoperable metadata format that entities can use to bootstrap the trust process.
The following sequence illustrates the use of SAML metadata to drive the SAML protocol flow.
1. Request the target resource at the SP
A browser user requests a web application resource protected by a SAML service provider:
https://sp.example.com/myresource
If a valid security context for the user principal already exists at the service provider, skip steps 2–13.
2. Redirect to the Discovery Service
Before the service provider can initiate the SAML protocol flow at step 6, the browser user's preferred identity provider must be known. There are numerous ways to do this. For illustration purposes, the service provider will use a local Discovery Service that conforms to the Identity Provider Discovery Service Protocol and Profile.
The service provider redirects the browser user to the Discovery Service:
302 Redirect
Location: https://ds.example.com/idpdisc?entityID=https%3A%2F%2Fsso.example.org%2Fportal
Note that the SP entityID is included in the redirect URL as specified by the discovery protocol.
3. Request the Discovery Service
The browser user requests the Discovery Service by virtue of the redirect:
GET /idpdisc?entityID=https%3A%2F%2Fsso.example.org%2Fportal HTTP/1.1
Host: ds.example.com
(Discover the user's preferred IdP)
The Discovery Service discovers the browser user's preferred identity provider by unspecified means.
4. Redirect to the Discovery Response endpoint at the SP
The Discovery Service now redirects the browser user to a Discovery Response endpoint at the service provider:
302 Redirect
Location: https://sp.example.com/SAML2/Login?entityID=https%3A%2F%2Fsso.example.org%2Fidp
Note that the IdP entityID is included in the redirect URL as specified by the discovery protocol.
5. Request the Discovery Response endpoint at the SP
The browser user requests the Discovery Response endpoint at the service provider by virtue of the redirect:
GET /SAML2/Login?entityID=https%3A%2F%2Fsso.example.org%2Fidp HTTP/1.1
Host: sp.example.com
The Discovery Response endpoint at the service provider conforms to the Identity Provider Discovery Service Protocol and Profile.
6. Redirect to SSO Service at the IdP
The service provider generates a relevant <samlp:AuthnRequest> element, encodes a SAML Request in an URL query string, and then redirects the browser user to the Single Sign-On Service at the identity provider:
302 Redirect
Location: https://idp.example.org/SAML2/SSO/Redirect?SAMLRequest=request&RelayState=token
For an outline how to construct the query string, see the corresponding SAML protocol flow in the SAML 2.0 article. Refer to SAMLCore for details.
7. Request the SSO Service at the IdP
The browser user requests the Single Sign-On Service endpoint at the identity provider by virtue of the redirect:
GET /SAML2/SSO/Redirect?SAMLRequest=request&RelayState=token HTTP/1.1
Host: idp.example.org
8. Respond with the login page
The identity provider returns a login page to the user's browser. The login page contains an HTML form similar to the following:
<form method="post" action="https://idp.example.com/login-response" ...>
Username:<br>
<input type="text" name="username"><br>
Password:<br>
<input type="password" name="password">
...
<input type="submit" value="Submit" />
</form>
9. Submit the login form
The browser user submits the HTML form to the identity provider:
POST /login-response HTTP/1.1
Host: idp.example.com
Content-Type: application/x-www-form-urlencoded
Content-Length: nnn
username=username&password=password
(Issue a SAML Assertion for the user)
At this point, the identity provider knows the identity of the user principal and so the identity provider constructs a SAML Assertion on behalf of the user principal. For a concrete example of such an Assertion, see the corresponding SAML protocol flow in the SAML 2.0 article. As always, refer to SAMLCore for details.
The <saml:NameID> element in the SAML Assertion encodes an identifier for the user principal. In this case, the identity provider includes a SAML2 Transient NameID (SAMLCore) in the SAML Assertion.
The identity provider includes two user attributes in the SAML Assertion: eduPersonUniqueId and mail.
Operationally, the identity provider digitally signs and encrypts the SAML Assertion, wraps the Assertion in a SAML Response, and then signs the Response object as well. Typically the identity provider signs the Response alone but in this case both the Assertion and the Response are digitally signed.
10. Respond with the SAML Response page
The identity provider returns an XHTML document to the user's browser. The document contains a SAML Response encoded in an XHTML form as follows:
<form method="post" action="https://sp.example.com/SAML2/SSO/POST" ...>
<input type="hidden" name="SAMLResponse" value="response" />
<input type="hidden" name="RelayState" value="token" />
...
<input type="submit" value="Submit" />
</form>
11. Request the Assertion Consumer Service at the SP
The XHTML form is automatically submitted by the browser (due to a small bit of JavaScript on the page):
POST /SAML2/SSO/POST HTTP/1.1
Host: sp.example.com
Content-Type: application/x-www-form-urlencoded
Content-Length: nnn
SAMLResponse=response&RelayState=token
12. Redirect to the target resource
The service provider creates a security context for the user principal and redirects the browser user to the original web application resource:
302 Redirect
Location: https://sp.example.com/myresource
13. Request the target resource at the SP again
Finally the browser user requests the target resource at the service provider by virtue of the redirect:
https://sp.example.com/myresource
14. Respond with requested resource
Since a security context exists, the service provider returns the resource to the browser user agent as requested.
See also
Security Assertion Markup Language (SAML)
SAML 2.0
XML (eXtensible Markup Language)
XML Schema (W3C)
XML Signature
XML Encryption
References
Liberty metadata specifications
Note: The Liberty metadata schema are listed verbatim in the specification documents listed below. Since the direct link to the Version 1.1 XSD document on the Liberty web site is broken, a copy of the XSD document for Liberty Metadata Version 1.1 has been uploaded to the web. That document is also included in the legacy Liberty ID-FF 1.2 archive.
SAML metadata specifications pre-2005
SAML standards
The original SAML V2.0 standards published in March 2005 have been deprecated in favor of the revised specifications with errata listed further below.
S. Cantor et al. Assertions and Protocols for the OASIS Security Assertion Markup Language (SAML) V2.0. OASIS Standard, March 2005. Document ID saml-core-2.0-os http://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf
S. Cantor et al. Bindings for the OASIS Security Assertion Markup Language (SAML) V2.0. OASIS Standard, March 2005. Document ID saml-bindings-2.0-os http://docs.oasis-open.org/security/saml/v2.0/saml-bindings-2.0-os.pdf
J. Hughes et al. Profiles for the OASIS Security Assertion Markup Language (SAML) V2.0. OASIS Standard, March 2005. Document ID saml-profiles-2.0-os http://docs.oasis-open.org/security/saml/v2.0/saml-profiles-2.0-os.pdf
S. Cantor et al. Metadata for the OASIS Security Assertion Markup Language (SAML) V2.0. OASIS Standard, March 2005. Document ID saml-metadata-2.0-os http://docs.oasis-open.org/security/saml/v2.0/saml-metadata-2.0-os.pdf
Except for historical references to the original SAML V2.0 Metadata Standard, the following footnotes point to SAML V2.0 specifications with errata. The latter specifications are fully inclusive of all errata approved by the OASIS Security Services (SAML) Technical Committee since the SAML V2.0 standards were published in March 2005. Please refer to the OASIS SAML Wiki for the most recent version of any SAML specification.
Committee specifications post-2005
This is a small subset of the "Post-V2.0" committee specifications published by the OASIS Security Services (SAML) Technical Committee. Please refer to the OASIS SAML Wiki for the most recent version of any SAML specification.
Miscellaneous
XML-based standards
Metadata standards | SAML metadata | [
"Technology"
] | 9,957 | [
"Computer standards",
"XML-based standards"
] |
54,953,948 | https://en.wikipedia.org/wiki/Type%201%20regulatory%20T%20cell | Type 1 regulatory cells or Tr1 (TR1) cells are a class of regulatory T cells participating in peripheral immunity as a subset of CD4+ T cells. Tr1 cells regulate tolerance towards antigens of any origin. Tr1 cells are self or non-self antigen specific and their key role is to induce and maintain peripheral tolerance and suppress tissue inflammation in autoimmunity and graft vs. host disease.
Characterization and surface molecules
The specific cell-surface markers for Tr1 cells in humans and mice are CD4+ CD49b+LAG-3+ CD226+ from which LAG-3+ and CD49b+ are indispensable. LAG-3 is a membrane protein on Tr1 cells that negatively regulates TCR-mediated signal transduction in cells. LAG-3 activates dendritic cells (DCs) and enhances the antigen-specific T-cell response which is necessary for Tr1 cells antigen specificity. CD49b belongs to the integrin family and is a receptor for many (extracellular) matrix and non-matrix molecules. CD49b provides only little contribution to the differentiation and function of Tr1 cells.
They characteristically produce high levels of IL-10, IFN-γ, IL-5 and also TGF- β but neither IL-4 nor IL-2. Production of IL-10 is also much more rapid than its production by other T-helper cell types.
Tr1 cells do not constitutively express FOXP3 but only transiently, upon their activation and in smaller amounts than CD25+ FOXP3+ regulatory cells. FOXP3 is not required for Tr1 induction, nor for its function. They also express repressor of GATA-3 (ROG), while CD25+ FOXP3+ regulatory cells do not. ROG then downregulates GATA-3, a characteristic transcription factor for Th2 cells.
Tr1 cells express high levels of regulatory factors, such as glucocorticoid-induced tumor necrosis factor receptor (GITR), OX40 (CD134), and tumor-necrosis factor receptor (TNFRSF9). Resting human Tr1 cells express Th1 associated chemokine receptors CXCR3 and CCR5, and Th2-associated CCR3, CCR4 and CCR8. Upon activation, Tr1 cells migrate preferentially in response to I-309, a ligand for CCR8.
Mechanism of Tr1-mediated suppression
The suppressing and tolerance-inducing effect of Tr1 cells is mediated mainly by cytokines. The other mechanism as cell to cell contact, modulation of dendritic cells, metabolic disruption and cytolysis is however also available to them. In vivo Tr1 cells need to be activated, to be able to exert their regulatory effects.
Mechanisms of suppression
Cytokines mediated
Tr1 cells secrete large amount of suppressing cytokines IL-10 and TGF-β. IL-10 directly inhibits T cells by blocking its production of IL-2, IFN-γ and GM-CSF and have tolerogenic effect on B cells and support differentiation of other regulatory T cells. IL-10 indirectly downregulates MHC II molecules and co-stimulatory molecules on antigen-presenting cells (APC) and force them to upregulate tolerogenic molecules such as ILT-3, ILT-4 and HLA-G.
Cell to cell contact:
Type 1 regulatory T cells poses inhibitory receptor CTLA-4 through which they exert suppressor function.
Metabolic disruption:
Tr1 cells can express ectoenzymes CD39 and CD73 and are suspected of generating adenosine which suppresses effector T cell proliferation and their cytokine production in vitro.
Cytolitic activity:
Tr1 cells can both express Granzyme A and granzyme B. It was shown recently, that Tr1 cells, in vitro and also ex vivo, specifically lyse cells of myeloid origin, but not other APC or T or B lymphocytes. Cytolysis indirectly suppresses immune response by reducing numbers of myeloid-origin antigen presenting cells.
Differentiation
Tr 1 cells are inducible, arising from precursors naive T cells. They can be differentiated ex vivo and in vivo. The ways of Tr1 cells induction in vivo, ex vivo and in vitro differ and also envelop many different approaches but the molecular mechanism appears to be conserved.
IL-27, together with TGF-β induces IL-10–producing regulatory T cells with Tr1-like properties cells. IL-27 alone can induce IL-10-producing Tr1 cells, but in the absence of TGF-β, the cells produce large quantities of both IFN-γ and IL-10. IL-6 and IL-21 also plays a role in differentiation as they regulate expression of transcription factors necessary for IL-10 production, which is believed to start up the differentiation itself later on.
Proposed transcription biomarkers for type 1 regulatory cells differentiation are:
musculoaponeurotic fibrosarcoma(c-Maf)
the aryl hydrocarbon receptor (AhR)
interferon regulatory factor 4 (IRF4)
the repressor of GATA-3 (ROG)
early growth response protein 2 (Egr-2)
Expression of these transcriptional factors are driven by IL-6 in IL-21 and IL-2 dependant manner.
Clinical manifestation and application
Tr1 cells possess huge clinical potential in means to prevent, block and even cure several T cells mediated diseases, including GvHD, allograft rejection, autoimmunity and chronic inflammatory diseases. The first successful tests were performed on mouse models and on humans as well.
Transplantation research has shown, that donor Tr1 in response to recipient alloantigens, was found to correlate with the absence of GvHD after bone marrow transplantation, while decreased numbers of Tr1 markedly associated with severe GvHD. Decreased levels of IL-10 CD4+ producing cells were also observed in inflamed synovium and peripheral blood of patients with rheumatoid arthritis.
Phase I/II of clinical trials of Tr1 cell treatment concerning Crohn's disease have been successful and appear to be safe and do not lead to a general immune suppression.
References
Cell biology
Immunology
Immune system | Type 1 regulatory T cell | [
"Biology"
] | 1,341 | [
"Immune system",
"Organ systems",
"Immunology",
"Cell biology"
] |
54,954,311 | https://en.wikipedia.org/wiki/NGC%205617 | NGC 5617 is an open cluster in the constellation Centaurus. NGC 5617 forms a binary open cluster with Trumpler 22. It lies one degree west-northwest of Alpha Centauri.
Observation history
It was discovered by James Dunlop in 1826. He described it on May 8, 1826 as "a cluster of small stars of mixed magnitudes, considerably congregated towards the centre, 4' or 5' in diametre" and added it to his catalog as number 302. John Herschel described as "Class IV object, very rich; irregularly round; pretty much compressed in the middle but scattered at borders; 15'; there are three stars of 10th magnitude, 5 or 6 stars of 11th magnitude; the rest below 11th" and added it to General Catalogue as No. 3570. In the New General Catalogue it is described as "large (10'), richer in stars to the west (about 80 total), with a compressed middle. It contains stars of magnitude 8 and fainter."
Characteristics
NGC 5617 is located nearly 2 kpc (6.500 light years) away from Earth, at the further border of Carina-Sagittarius arm. Various photometric studies have produced different results concerning the age and the distance of the cluster; Moffat & Vogt (1975) studied and calculated a distance of 1.34 kpc from the Sun, Haug (1978) found its distance to be 1.82 kpc, a CCD photometry by Kjeldsen & Frandsen (1991) found the distance to be 2.05 ± 0.2 kpc and the age 70 Myr and Carra & Munari (2004) used BVI photometry to obtain reddening EB−V= 0.48 ± 0.05, age of 80 Myr, and a distance of 2.0 ± 0.3 kpc. De Silva et al. (2015) calculated its distance at 2.1 ± 0.3 kpc. Bisht et al. found an age of 90 ± 10 Myr and a parallax-derived distance of 2.43 ± 0.08 kpc, in good agreement with isochrone-derived values.
There are 175 probable member stars within the angular radius of the cluster and 65 within the central part of the cluster. The tidal radius of the cluster is 7.4 - 10.2 parsecs (24 - 33 light years) and represents the average outer limit of NGC 5617, beyond which a star is unlikely to remain gravitationally bound to the cluster core. One blue straggler is a possible member of the cluster. Other possible members of the cluster are delta Scuti variable, gamma Doradus variable and eclipsing variable stars.
NGC 5617, along with its companion Trumpler 22, appear to be dynamically relaxed, with massive stars concentrated near the center and less massive stars in the periphery.
Relation with Trumpler 22
NGC 5617 appears to be gravitationally bound to Trumpler 22. The two clusters share similar radial velocities (-38.63 ± 2.25 km/s for NGC 5617 and -38.46 ± 2.08 km/s for Trumpler 22), mean metallicity (-0.18 ± 0.02 for NGC 5617 and-0.17 ± 0.04 for Trumpler 22), similar abundances across various elements, and have similar age, forming a primordial binary cluster pair. Their orbits were initially almost circular and their separation less than 20 pc.
References
External links
5617
Centaurus
Open clusters
Astronomical objects discovered in 1826
Discoveries by James Dunlop | NGC 5617 | [
"Astronomy"
] | 746 | [
"Centaurus",
"Constellations"
] |
54,955,510 | https://en.wikipedia.org/wiki/NGC%204454 | NGC 4454 is a barred spiral galaxy located about 123 million light-years away in the constellation of Virgo. NGC 4454 was discovered by astronomer William Herschel on April 17, 1784.
One supernova, SN 2020abgq (type Ia, mag. 16.3), was discovered in NGC 4454 on 30 November, 2020.
See also
List of NGC objects (4001–5000)
NGC 4314
References
External links
Barred spiral galaxies
Virgo (constellation)
4454
41083
7606
Astronomical objects discovered in 1784 | NGC 4454 | [
"Astronomy"
] | 112 | [
"Virgo (constellation)",
"Constellations"
] |
54,956,115 | https://en.wikipedia.org/wiki/Ethics%20in%20mathematics | Ethics in mathematics is an emerging field of applied ethics, the inquiry into ethical aspects of the practice and applications of mathematics. It deals with the professional responsibilities of mathematicians whose work influences decisions with major consequences, such as in law, finance, the military, and environmental science. When understood in its socio-economic context, the development of mathematical works can lead to ethical questions ranging from the handling and manipulation of big data to questions of responsible mathematisation and falsification of models, explainable and safe mathematics, as well as many issues related to communication and documentation. The usefulness of a Hippocratic oath for mathematicians is an issue of ongoing debate among scholars. As an emerging field of applied ethics, many of its foundations are still highly debated. The discourse remains in flux. Especially the notion that mathematics can do harm remains controversial.
The ethical questions surrounding the practice of mathematics can be connected to issues of dual-use. An instrumental interpretation of the impact of mathematics makes it difficult to see ethical consequences, yet it might be easier to see how all branches of mathematics serve to structure and conceptualize solutions to real problems. These structures can set up perverse incentives, where targets can be met without improving services, or league table positions are gamed. While the assumptions written into metrics often reflect the worldview of the groups who are responsible for designing them, they are harder for non-experts to challenge, leading to injustices. As mathematicians can enter the workforce of industrialised nations in many places that are no longer limited to teaching and academia, scholars have made the argument that it is necessary to add ethical training into the mathematical curricula at universities.
The philosophical positions on the relationship between mathematics and ethics are varied. Some philosophers (e.g. Plato) see both mathematics and ethics as rational and similar, while others (e.g. Rudolf Carnap) see ethics as irrational and different from mathematics. Possible tensions between applying mathematics in a social context and its ethics can already be observed in Plato's Republic (Book VIII) where the use of mathematics to produce better guardians plays a critical role in its collapse.
Need for ethics in the mathematics profession
Mathematicians in industrial, scientific, military and intelligence roles crucially influence decisions with significant consequences.
Issues of accuracy
For example, complex calculations were needed for the success of the Manhattan Project, while the overextended use of the Gaussian copula formula to price derivatives before the Global Financial Crisis of 2008 has been called "the formula that killed Wall Street", and the theory of global warming depends on the reliability of mathematical models of climate.
Issues of impact
For the same reason as in medical ethics and engineering ethics, the high impact of the consequences of decisions imposes serious ethical obligations on practitioners to consider the rights and wrongs of their advice and decisions. The potential impact of data and new technology is leading more professions, such as accountancy, to consider how bias is overseen in automated systems, from algorithms to AI. Due to its large impact and its necessity in the modern industrialised world, mathematics has been labelled as a new factor of production by some scholars. Mathematics is a fundamental driver of today's economies and plays an everyday role in the decision making in capitalist markets. When studied in its socio-economic context, the debates surrounding the ethical use of mathematics often go under different names, e.g. some people speak of the ethics of quantification. These discourses are often disjoint from those directly affecting or driven by parts of the mathematical community.
Disasters involving the use of mathematics
These illustrate the major consequences of numerical mistakes and hence the need for ethical care.
The Club of Rome's 1972 mathematical-model-based predictions in The Limits to Growth of widespread collapse of the world system by the end of the 21st century.
The wrongful conviction of Sally Clark (1999), An English solicitor, Sally Clark, was wrongfully convicted of murdering her two children – each of whom had died due to sudden infant death syndrome – due to a fundamental statistical error in the testimony of an "expert". The error was further compounded by the "prosecutor's fallacy".
Ethical issues in the mathematical profession
Mathematicians have a professional responsibility to support the ethical use of mathematics in practice, both to sustain the reputation of the profession and to protect society from the impacts of unethical behavior. For example, mathematics is extensively applied in the use of Big Data in Artificial Intelligence applications, both by mathematicians and non-mathematicians, with complex impacts that are not readily understood or anticipated.
Ethics in data journalism
Journalism has established Professional ethics which is affected by mathematical processing and (re-)publication of sources. Reusing information packaged as facts require checking, and validating, from conceptual confusion to sampling and calculation errors. Other professional issues arise from the potential of automated tools which allow the dissemination of publicly available data which has never been collated.
Misuse of statistics
Applications of mathematics generally involve drawing conclusions from quantitative data. Due to uncertainties that mathematical models deal with, and challenges in drawing and communicating any conclusions, there is a possibility of mathematicians misleading the clients as they are not generally aware of quantitative techniques. To avoid such instances, statisticians codified their ethics in the 1980s in a declaration of the ISI, recognizing that there would often be conflicting demands from stakeholders, with ethical decisions a matter of professional judgment.
Mathematical folklore
Priority and attribution of mathematical discovery are important to professional practice, even as some theorems bear the name of the person making the conjecture rather than finding the proof. Folk theorems, or mathematical folklore cannot be attributed to an individual, and may not have an agreed proof, despite being an accepted result, potentially leading to injustice.
Ethics in pure mathematical research
The American Mathematical Society publishes a code of ethical guidelines for mathematical researchers. The responsibilities of researchers include being knowledgeable in the field, avoiding plagiarism, giving credit, publishing without unreasonable delay, and correcting errors. The European Mathematical Society Ethics Committee also publishes a code of practice relating to the publication, editing and refereeing of research.
It has been argued that as pure mathematical research is relatively harmless, it raises few urgent ethical issues. However, that raises the question of whether and why pure mathematics is ethically worth doing, given that it consumes the lives of many highly intelligent people who could be making more immediately useful contributions.
The study of ethical challenges in pure mathematics is deeply connected to the philosophy of mathematical practice. Arguments against the ethical neutrality of pure mathematical work often builds on the social constitution, i.e. the socio-cultural context of the research and the many decisions involved in mathematical proofs. The problem of epistemic injustice in mathematical research is actively discussed in this context.
Parallels between ethics and mathematics
Ethics and mathematics both appear to rely on reasoning from intuition, unlike empirical sciences which rely fundamentally on observations and experiments. That has been suggested as a reason in support of objectivity or moral realism in ethics, since arguments against objectivity in ethics are paralleled by arguments against objectivity in mathematics, which is generally believed to be false.
Justin Clarke-Doane argues to the contrary that although mathematics and ethics are closely parallel, a pluralist attitude should be taken to the truths of both. Just as the parallel postulate is true in Euclidean geometry but false in non-Euclidean geometry, so ethical propositions can be true or false in different systems.
Teaching ethics in mathematics
Courses in the ethics of mathematics remain rare. The University of New South Wales taught a compulsory course on Professional Issues and Ethics in Mathematics in its mathematics degrees from 1998 to 2012. In 2023, the ETH Zurich taught an optional seminar on ethics in mathematics and a non-examinable seminar also exists at the University of Cambridge. A mini-seminar has also been taught at Swarthmore College.
Many courses considering ethics in mathematics also appear under different names, e.g. "mathematics for social justice."
Similar approaches can also be found in the teaching of ethics to computer science students, where the term "embedded ethics" has established itself for the integration of ethics teaching into the curriculum. These programmes are currently explored at Harvard University, Stanford University and other places.
See also
Ethics of quantification - Ethics of quantification
Ethics of artificial intelligence - Ethics of artificial intelligence and machine learning
Critical mathematics pedagogy - Pedagogical approach behind some of the courses on ethics in mathematics and mathematics for social justice
Notes
References
Aitken, C., Roberts, P. & Jackson, G., Communicating and Interpreting Statistical Evidence in the Administration of Criminal Justice, Practitioner Guide No.1: Fundamentals of Probability and Statistical Evidence in Criminal Proceedings: Guidance for Judges, Lawyers, Forensic Scientists and Expert Witnesses, Royal Statistical Society, 2010 .
Alayont, F. (2022), "A Case for Ethics in the Mathematics Major Curriculum", Journal of Humanistic Mathematics, Vol.12, No.2, (July 2022), pp.160-177.
Balinski, M., "What is just?", American Mathematical Monthly, Vol.112, No.6, (June-July 2005), pp. 502-511.
Boylan, M., "Ethical Dimensions of Mathematics Education", Educational Studies in Mathematics, Vol.92, No.3, (July 2016), pp. 395–409.
Buell C, Piercey V. (2022), "Special Issue Ethics in Mathematics: Foreword", Journal of Humanistic Mathematics, Vol.12, No.2, (July 2022), pp.3-6.
Dubbs, Christopher (2020), "Whose Ethics? Toward Clarifying Ethics in Mathematics Education Research", Journal of Philosophy of Education, Vo.54, No.3, (June 2020), pp.521-540.
Dworkin, G., "A Journal of Mathematical Ethics: A Proposal", The Philosophical Forum, Vol.13, No.4, (Summer 1982), pp. 413–415.
Ernest, P. "What is Our First Philosophy in Mathematics Education?", For the Learning of Mathematics, Vol.32, No.3, (November 2012), pp. 8–14.
Ernest, P., "A Dialogue on the Ethics of Mathematics", The Mathematical Intelligencer, Vol.38, No.3, (September 2016), pp. 69–77.
Ernest, P., "The Ethics of Mathematics: Is Mathematics Harmful?", Ernest, P., (Ed.)The Philosophy of Mathematics Education Today. Switzerland: Springer, 2018, pp 187-216.
Franklin, J., "On the Parallel Between Mathematics and Morals", Philosophy, Vol.79, No.1, (January 2004), pp. 97–119.
Henrich, D., "Mathematical Ethics: Values, Valences and Virtue", Philosophy of Mathematics Education Journal, No.29, (July 2015).
Kambartel, Friedrich (1972), "Ethik und Mathematik", pp.489–503 in Riedel, Manfred (ed.), Rehabilitierung Der Praktischen Philosophie, Band I: Geschichte, Probleme, Aufgaben, Freiburg im Breisgau: Rombach Verlag.
Kambartel, Freidrich (trans. Gervasi, J.A. & Rentsch, T.) (1984), "Ethics and Mathematics", pp.49-61 in Christensen, D.E. (ed.), Contemporary German Philosophy, Volume 4, University Park, PA: Pennsylvania State University Press.
Lesser, L.M. & Nordenhaug, E., "Ethical statistics and statistical ethics: Making an interdisciplinary module", Journal of Statistics Education, Vol.12, No.3, (November 2004), pp. 50–56.
Levy, D.M. & Peart, S.J., "Inducing Greater Transparency: Towards the Establishment of Ethical Rules for Econometrics", Eastern Economic Journal, Volume 34, Issue 1, (January 2008), pp 103–114.
Miller A.N. (2022). "A Mini-seminar: Teaching Ethics in Mathematics in an Hour a Week", Journal of Humanistic Mathematics. 12(2): 178-203.
Nickel G. (2022), "Ethics and Mathematics Some Observations Fifty Years Later", Journal of Humanistic Mathematics, Vol.12, No.2, (July 2022), pp.7-27.
Spindler, R. (2022), "Foundational Mathematical Beliefs and Ethics in Mathematical Practice and Education", Journal of Humanistic Mathematics, Vol.12, No.2, (July 2022), pp.49-71.
Stinson, D.W., "In Search of Defining Ethics in (Mathematics) Education Research?", Journal of Urban Mathematics Education, Vol.10, No.1, (July 2017), pp. 1–6.
Strasak, A. M, Zaman, Q, Pfeiffer, K. P., Göbel, G. & Ulmer, H., "Statistical errors in medical research — a review of common pitfalls", Swiss Medical Weekly, (2007), 137: 44–49 .
Vardeman, S.B. & Morris, M.D., "Statistics and Ethics: Some Advice for Young Statisticians", The American Statistician, Vol.57, No.1, (February 2003), pp. 21–6.
Young, J., "Statistical errors in medical research — a chronic disease?", Swiss Medical Weekly, (2007), 137: 41–43 : editorial commentary (and elaboration) on Strasak, et al. by the Swiss Medical Weekly's Statistical Advisor.
External links
Cambridge University Ethics in Mathematics Society
American Mathematical Society: Policy Statement on Ethical Guidelines
Royal Statistical Society: Statistics and the Law.
Ethics of science and technology
Philosophy of statistics
Philosophy of mathematics
Ethics and statistics
Business ethics
Professional ethics | Ethics in mathematics | [
"Mathematics",
"Technology"
] | 2,888 | [
"Ethics and statistics",
"Philosophy of statistics",
"nan",
"Ethics of science and technology"
] |
54,957,376 | https://en.wikipedia.org/wiki/Indian%20Basket | Indian Basket (IB), also known as Indian Crude Basket, is weighted average of Dubai and Oman (sour) and the Brent Crude (sweet) crude oil prices. It is used as an indicator of the price of crude imports in India and Government of India watches the index when examining domestic price issues.
Methodology for calculation
The Indian basket of Crude Oil represents a derived basket comprising Sour grade (Oman and Dubai average) and Sweet grade (Brent Dated) of Crude oil processed in Indian refineries. During the year 2018-19, the ratio is 75.50 : 24.50 (Dubai : Brent respectively) and during the year 2017-2018, the ratio was 74.77 : 25.23 (Dubai : Brent). The Indian Basket is weighted average of daily prices and is updated daily on the website of the Petroleum Planning and Analysis Cell of the Ministry of Petroleum and Natural Gas.
Indian Basket prices
See also
Benchmark (crude oil)
References
External links
Benchmark crude oils
Petroleum | Indian Basket | [
"Chemistry"
] | 200 | [
"Petroleum",
"Chemical mixtures"
] |
54,957,668 | https://en.wikipedia.org/wiki/Bicycloaromaticity | Bicycloaromaticity in chemistry is an extension of the concept of homoaromaticity with two aromatic ring currents situated in a non-planar molecule and sharing the same electrons. The concept originates with Melvin Goldstein who first reported about it in 1967. It is of some importance in academic research. Using MO theory the bicyclo[3.2.2]nonatrienyl cation was predicted to be destabilised and the corresponding anion predicted to be stabilised by bicycloaromaticity.
Bicycloaromaticity has been studied by others in relation to the bicyclo[3.2.2]nonatrienyl cation and in relation to specific carbanions. In 2017 experimental evidence was reported for bicycloaromaticity (dual aromaticity) to exist in a bicyclic porphyrinoid. This system has been described as aromatic with two ring systems of 26 (n=6) and 34 (n=8) electrons. By oxidation, another system was described as a triplet-state biradical, again considered aromatic by application of Baird's rule.
References
Physical organic chemistry | Bicycloaromaticity | [
"Chemistry"
] | 241 | [
"Physical organic chemistry"
] |
54,957,827 | https://en.wikipedia.org/wiki/NGC%205316 | NGC 5316 is an open cluster in the constellation Centaurus. It was discovered by James Dunlop in 1826. Located approximately 4,000 light years away from Earth, it is located in the Carina-Sagittarius arm.
There are 570 probable member stars within the angular radius of the cluster and 262 within the central part of the cluster. The tidal radius of the cluster is 6.0 - 8.1 parsecs (19 - 26 light years) and represents the average outer limit of NGC 5316, beyond which a star is unlikely to remain gravitationally bound to the cluster core. The brightest member of the cluster (lucida) is star No. 31 (mag. 9.40). Star 31 has significantly more barium than the rest of the group and the Ba II line is visually stronger than the rest of the cluster. The turn-off mass of the cluster is estimated to be at 5.0 . The hottest stars of the cluster are of spectral type B5–B7. NGC 5316 has metallicity nearly the same as the solar one ([Fe/H] = −0.02 ± 0.05).
The age of the cluster has been estimated to be from as low as 51 myr (by the first photometric study of the cluster, in 1968, by Lindoff) to as high as 195 myr (by Battinelli & Capuzzo-Dolcetta, 1991). Pedreros et al. estimated its age to be (1.24 ± 0.15) × 108 years from ZAMS fitting the cluster (Pedreros, 1987) and the UBVI CCD photometric study of the cluster by Carraro et al. estimated its age to be 100 ± 10 million years.
References
External links
5316
Centaurus
Open clusters | NGC 5316 | [
"Astronomy"
] | 372 | [
"Centaurus",
"Constellations"
] |
54,959,185 | https://en.wikipedia.org/wiki/Spiroligomer | Spiroligomer molecules (also known as bis-peptides) are synthetic oligomers made by coupling pairs of bis-amino acids into a fused ring system. Spiroligomer molecules are rich in stereochemistry and functionality because of the variety of bis-amino acids that are capable of being incorporated during synthesis. Due to the rigidity of the fused ring system, the three-dimensional shape of a Spiroligomer molecule – as well as the display of any functional groups – can be predicted, allowing for molecular modeling and dynamics.
Synthesis
Spiroligomer molecules are synthesized in a step-wise approach by adding a single bis-amino acid at each stage of the synthesis. This stepwise elongation allows for complete control of the stereochemistry, as any bis-amino acid can be incorporated to allow for elongation; or any mono-amino acid can be added to terminate a chain. This can be accomplished using either solution-phase or solid-phase reactions. The original synthesis of Spiroligomer molecule allowed for functionalization on the ends of the oligomers, but it did not allow for the incorporation of functionality on the interior diketopiperazine (DKP) nitrogens. Much work has been done to allow for the functionalization of the entire Spiroligomer molecule, as opposed to just the ends. By exploiting a neighboring group effect, Spiroligomer molecule can be synthesized with a variety of functional groups along the length of the molecule.
Structure
Spiroligomer molecules can be synthesized in any direction, and between any pair of bis-amino acids.
Spiroligomer diketopiperazines can be created between either end of a bis-amino acid.
Spiroligomer molecules are known to be conformationally rigid, due to the fused-ring backbone.
Chemical characteristics
Spiroligomer molecules are peptidomimetics, completely resistant to proteases, and not likely to raise an immune response.
Uses
Spiroligomer molecules have been utilized for a variety of applications which include catalysis, protein binding, metal-binding, molecular scaffolds, and charge-transfer studies, et al.
Catalysis
Two unique types of Spiroligomer catalysts (spiroligozymes) have been developed, an esterase mimic and a Claisen catalyst.
Transesterification
The first Spiroligomer catalyst was an esterase-mimic, which catalyzed the transfer of a trifluoroacetate group.
Aromatic Claisen rearrangement
The second Spiroligomer catalyst accelerated an aromatic Claisen rearrangement with a catalytic dyad similar to that found in ketosteroid isomerase.
Protein binding
A Spiroligomer peptidomimetic was designed to mimic P53 and bind HDM2. The molecule enters cells through passive diffusion, and this mimic was shown to stabilize HDM2 in cell culture.
Metal binding
Binuclear metal binding
Molecular scaffolds
Rods used for distance measuring with spin probes.
Electron transfer
Donor-Bridge-Acceptor
Other uses
Possible applications that are currently investigated include the binding and inactivation of cholera toxin and the cross linkage of surface proteins of various viruses (HIV, Ebola virus). Further the group of Christian Schafmeister developed molecular hinges, which can be used for the construction of molecular machines, such as nano-valves or data storage systems.
See also
Molecular engineering
Molecular machine
Molecular nanotechnology
Nanotechnology
References
Oligomers
Amino acids
Molecular modelling
Molecular biology | Spiroligomer | [
"Chemistry",
"Materials_science",
"Biology"
] | 745 | [
"Biomolecules by chemical classification",
"Molecular physics",
"Organic compounds",
"Amino acids",
"Theoretical chemistry",
"Molecular modelling",
"Polymer chemistry",
"Molecular biology",
"Biochemistry",
"Oligomers"
] |
54,959,609 | https://en.wikipedia.org/wiki/Joseph%20C.%20Krejci | Joseph C. Krejci (December 19, 1910 – August 23, 1991) was a chemical engineering associate and manager of the Pyrolysis section at the Phillips Carbon Black Research facility in Borger, Texas. He is known for his work in developing the oil furnace production process for carbon black.
Personal
Krejci was born on 19 December 1910 in Galveston, Texas, the 2nd of 9 children. He married Fay Deen Yarbro Jan. 29, 1938 in Mineral Wells. He died on 23 August 1991 in Borger, Texas.
Education
Dr. Krejci obtained his Bachelor of Science, master's of science and Ph.D. degrees in chemical engineering from the University of Texas.
Career
He was a chemical engineering associate and manager of pyrolysis at the Phillips Carbon Black Research facility in Borger. He retired in 1971 following 34 years of service.
Krejci was the inventor of 31 patents in the carbon black field, many of these were also patented outside the United States. His earliest patent was a process for producing furnace black. His most cited patent was for a process for improving yield and quality in the manufacture of high-reinforcing carbon black.
Awards and recognitions
1974 - Charles Goodyear Medal from the ACS Rubber Division
References
Polymer scientists and engineers
1910 births
1991 deaths | Joseph C. Krejci | [
"Chemistry",
"Materials_science"
] | 271 | [
"Polymer scientists and engineers",
"Physical chemists",
"Polymer chemistry"
] |
66,214,204 | https://en.wikipedia.org/wiki/Cortinarius%20britannicus | Cortinarius britannicus is a species of webcap. It is known only from Scotland, where it was found on clay soil among mosses under beech. The species produces small, purplish mushrooms. Along with five other British webcaps, C. britannicus was selected by Kew Gardens as a highlight of taxa described by the organisation's staff and affiliates in 2020.
Taxonomy
Cortinarius britannicus was described in a 2020 research note in the journal Fungal Diversity by Kare Liimatainen and Tuula Niskanen. The description was based on a collection made by Dave J. Savage in 2017 in Olrig Wood, Caithness, Scotland. The specific name refers to Britain, as this is where the species was first found. Phylogenetic analysis placed the species in Cortinarius subgenus Telamonia and section Bicolores. The species formed a sister group with C. cystidiobicolor.
C. britannicus was one of over 150 botanical and mycological taxa described by staff or affiliates of Kew Gardens in 2020. In a year-end round-up, Kew scientists selected ten highlights, one of which was six newly described British Cortinarius species: C. britannicus described from Caithness; C. scoticus and C. aurae from the Black Wood of Rannoch; C. subsaniosus from Cumbria; C. ainsworthii from Brighton; and C. heatherae from Heathrow Airport. In a press release, Kew identified Cortinarius species as "ecologically important in supporting the growth of plants, particularly trees such as oak, beech, birch and pine" and playing "a key role in the carbon cycling of woodlands and providing nitrogen to trees".
Description
Cortinarius britannicus mushrooms have a cap that is wide and a low convex shape. The cap is a greyish purple and hygrophanous. The edges of the cap have whitish fibrils. The adnexed gills are medium spaced. They are brown with paler edges. The stalk is long and thick at apex. It is cylindrical to somewhat tapering downwards. Silky, whitish fibrils cover a greyish purple base. The stem has a white universal veil, which forms incomplete girdle-like structures on the stem. The gills have no distinct odour.
Microscopic characteristics
The almond-shaped basidiospores measure 8 to 9 by 5 to micrometres (μm), averaging 8.6 by 5.6 μm. The spores have a depression above the hilum, and are moderately warty, especially at the apex. The spores are moderately to strongly dextrinoid, meaning that they stain reddish to reddish-brown when Melzer's reagent or Lugol's solution is applied. The basidia are 26 to 35 by 7 to 10 μm. They are roughly club-shaped, sporting four sterigmata. The flesh in the gills is made up of rusty-brown hyphae. They are moderately covered with spot-like encrustations. The pileipellis surface is pale, consisting of more or less parallel hyphae that are 5 to 13 μm wide with zebra-like incrustations. Lower hyphae are rusty brown, 25 to 30 μm wide, with abundant zebra-like incrustations.
Similar species
Cortinarius section Bicolores contains species that produce similar but much larger mushrooms. C. britannicus can be distinguished from other members of the subgenus by its combination of small-sized, purplish-coloured mushrooms and almond-shaped, medium-sized spores.
Ecology
The species is known only from Britain, where it was found on clay soil among mosses under beech (Fagus), specifically a European beech.
References
britannicus
Fungi described in 2020
Fungi of Europe
Fungus species | Cortinarius britannicus | [
"Biology"
] | 802 | [
"Fungi",
"Fungus species"
] |
66,215,897 | https://en.wikipedia.org/wiki/Trailblazer%20%28rocket%29 | Trailblazer was an American series of rockets used between 1959 and 1973 for research on atmospheric reentry. Both vehicles were tested at the Wallops Flight Facility on Wallops Island, Accomack County, Virginia and were located under the NASA Langley program (itself located at the Langley Research Center near Hampton, Virginia).
Trailblazer 1
Trailblazer 1 (thrust: 365 kN/82,055 lbf; mass: 3,400 kg/7,400 lb; height: 17.1 m/56.1 ft; diameter: 0.58 m/1.9 ft) was first launched on March 3, 1959, and was retired in 1963 (last launch: February 16, 1963). The vehicle had six stages: TX-77, M-6, M5E1, Cygnus 5, T-40, and T-55. Its first three stages took the upper stage package (Cygnus 5, T-40, and T-55 motors) to an apogee, either 260 km/162 mi or 280 km/170 mi, when the upper stages fired in unison, pushing the payload (a 13 cm sphere) back into Earth's atmosphere at sizable reentry speeds. In each test, a different material was used, and ground workers could observe the spectral density and luminance of the artificial "meteorites" that had been created. On the 1G mission, a more realistic artificial meteorite (a 5.8 g steel bearing) was used as the payload, which was launched into the atmosphere with a reentry speed of 6 km/s by a "seventh stage", used after the sixth stage had been depleted. Thus, a reference was provided for the luminance of the trails of the artificial meteorites resulting from later tests.
Trailblazer 2
Trailblazer 2 (thrust: 547 kN/122,970 lbf; mass: 6,100 kg/13,400 lb; height: 15.7 m/51.5 ft; diameter: 0.79 m/2.59 ft) was first launched on December 14, 1961, and was retired in 1973 (last launch: December 6, 1973). Trailblazer 2 sent objects back into the atmosphere much in the same way Trailblazer 1 did, however it was much larger and stronger than Trailblazer 1. Also, due to the sheer size of it, Trailblazer 2 could hold instruments for measuring and sending data to the ground, greatly enhancing its utility to researchers. Trailblazer 2's apogee was around 300 km/180 mi, and its payload was around 18 kg. Its stages were Altair 1, Cygnus 15, TX-77, 1.5KS35000, and Castor 1. Like Trailblazer 1, Trailblazer 2 carried out artificial meteorite experiments. It used 0.7-0.8 g steel balls that were launched at 6.1 km/s.
References
Description and Performance of Three Trailblazer II
Trailblazer 2 Rocket Tests on the Reentry Plasma Sheath
JSR Launch Logs, Jonathan C. McDowell
Sounding rockets of the United States | Trailblazer (rocket) | [
"Astronomy"
] | 654 | [
"Rocketry stubs",
"Astronomy stubs"
] |
66,215,909 | https://en.wikipedia.org/wiki/Wenxian%20Shen | Wenxian Shen is a Chinese-American mathematician known for her work in topological dynamics, almost-periodicity, waves and other spatial patterns in dynamical systems. She is Don Logan Chair of Mathematics at Auburn University.
Education
Shen graduated from Zhejiang Normal University in 1982, and earned a master's degree at Peking University in 1987. She completed a Ph.D. in mathematics at the Georgia Institute of Technology in 1992, with the dissertation Stability and Bifurcation of Traveling Wave Solutions supervised by Shui-Nee Chow.
Books
Shen is the coauthor of two monographs, Almost Automorphic and Almost Periodic Dynamics in Skew-Product Semiflows (with Yingfei Yi, American Mathematical Society, 1998), and Spectral Theory for Random and Nonautonomous Parabolic Equations and Applications (with Janusz Mierczyński, CRC Press, 2008).
References
External links
Home page
Year of birth missing (living people)
Living people
20th-century American mathematicians
21st-century American mathematicians
Chinese mathematicians
Chinese women mathematicians
Dynamical systems theorists
Zhejiang Normal University alumni
Peking University alumni
Georgia Tech alumni
Auburn University faculty
20th-century American women mathematicians
21st-century American women mathematicians | Wenxian Shen | [
"Mathematics"
] | 241 | [
"Dynamical systems theorists",
"Dynamical systems"
] |
66,215,930 | https://en.wikipedia.org/wiki/TC-S%207001 | TC-S 7001 (Azaindole-1) is a drug which acts as a potent and selective inhibitor of the enzyme Rho kinase, with an IC50 of 0.6 nM at ROCK1 and 1.1 nM at ROCK2. It has vasodilatory effects and has been used in research for a variety of applications.
See also
Rho kinase inhibitor
References
Enzyme inhibitors
Pyrrolopyridines
Pyrimidines
Fluoroarenes
Chloroarenes
Aromatic ethers | TC-S 7001 | [
"Chemistry"
] | 107 | [
"Pharmacology",
"Pharmacology stubs",
"Medicinal chemistry stubs"
] |
66,215,951 | https://en.wikipedia.org/wiki/Sleep%20tracking | Sleep tracking is the process of monitoring a person's sleep, most commonly through measuring inactivity and movement. A device that tracks a person's sleep is called a sleep tracker. Sleep tracking may be beneficial in diagnosing sleep disorders. As sleep abnormalities are also symptoms of mental illness or relapsing psychotic disorders, it may also be beneficial in diagnosing mental disorders and psychotic disorders as well.
Polysomnography, the "gold standard" method for sleep tracking that requires attaching electrodes and monitors to the patient as they sleep, was developed in the late 1950s. It is considered by sleep researchers as providing the most accurate sleep data, however, it is an expensive, often uncomfortable experience for patients with findings that may be skewed due to the "first night effect". The actigraphy, a sleep-tracking device that is worn on one's wrist, was developed in the early 1970s and uses motion sensors. It is considered the "silver standard" method of sleep tracking, is comparably less expensive than a polysomnograph, and easier to incorporate into a patient's every day schedule as it looks and feels like a wrist-watch. However, it cannot track sleep-staging, is still generally expensive, and still requires a specialist to analyze the data it collects.
Sleep trackers are now available to consumers in many different forms such as smartphones, smartwatches, fitness trackers, and other wearable devices. Compared to a polysomonograph or an actigraph, consumer sleep-tracking devices are already incorporated into the day-to-day lives of patients and are the most cost-effective sleep-tracking method for patients. However, consumer sleep-tracking devices as they currently are, do not provide reliable sleep data for consumers or healthcare professionals. Additionally, consumer sleep tracking devices do not share their sleep tracking methods or algorithms with the public and may unintentionally undermine the sleep recommendations of health professionals or the need to seek professional help regarding improving sleep quality.
Devices and methods
Developed in the late 1950s, a polysomnograph, also known as a polysomnogram or a 'sleep study', is a test used to diagnose sleep disorders and is considered as the best and most reliable method to collect sleep data from individuals. A person can undergo a polysomnograph during an overnight stay in either a hospital or in a sleep center (a laboratory). Prior to the start of the polysomnograph, electrodes are attached to the individual's scalp, chin, and outer eyelids to record signals and monitors are attached to the individual's chest to record their heart rate and track their breathing as they sleep. As the individual sleeps, they are monitored by polysomnograph technologist who will take notes on things such as changes in heart rate and breathing. Sometimes, there is also a video camera recording individual's movement as they sleep.
Developed in the early 1970s, an actigraphy device is one of the earliest devices used to track the stages of a person's sleep and identify sleep disorders. It is a non-invasive wearable device shaped like a wristwatch that tracks the movement of your body with accelerometers, small motion sensors. This device can collect data over an extended period of time, such as a few weeks or months. Actigraphy devices then uses the collected data to determine if the patient is asleep or awake and can also track the individual's other sleep behaviors such as wake time.
Sleep tracking is now possible through consumer wearable devices such as smartwatches and fitness trackers and applications on smartphones. The features that these consumer sleep-tracking devices offer can vary depending on the device, model, and version. Some sleep-tracking devices are capable of tracking the stages of a person's sleep (light sleep, deep sleep, REM sleep), the length/duration of a person's sleep, the quality of a person's sleep, and the consistency of a person's sleep. Other features offered by sleep-tracking devices may include "sleep scores" that rank how well a person slept, "smart alarms" that wake a person up within a set period of time based on the circumstances of the person's sleep, and the ability to track the amount of light and/or the temperature in the person's bedroom. Unlike university sleep labs, which have made their sleep algorithms public for many years, the algorithms and methods of data collection used in consumer sleep-tracking devices have not been made public as they are proprietary and can also change at any point in time without notification to the users.
Utilization and effectiveness
Sleep tracking can be used to track sleep abnormalities and the sleep quality of people and help healthcare providers diagnose their patients with sleep disorders. Sleep tracking can also be used for tracking sleep abnormalities that are symptoms of mental illness. For example, repeated sleep disturbances have been associated with increased risks of suicide, the development of mood disorders such as depression and anxiety, and relapse of psychotic disorders.
Polysomnography
Polysomnographies are considered the "gold standard" for sleep data collection. However, polysomnographies do not create an environment that is conducive for sleep for most patients, especially patients who already struggle with sleep abnormalities. They are typically inaccessible to the average patient and inconvenient, as they require patients to have wires clipped to their face and monitors strapped to their body, they may need to sleep outside of their typical sleeping environment, they may be uncomfortable with knowing that as they sleep they are being monitored by the polysomongraph technologist, and the test is too expensive to obtain sleep tracking data from one patient for an extended period of time. One night of sleep tracking using a polysomnograph and a polysomongraph technologist can cost up to $2,000. There is the "one night effect" where patients will experience more difficulties with sleeping (reflected in decreased REM sleep, decreased sleep efficiency, and increased sleep latency) during their first night of sleep tracking via polysomongraphy due to the sleep tracking equipment and unusual sleeping circumstances. Additionally, the data collected during a polysomnography can also be subjected to human error.
Actigraphy
Actigraphies are considered "silver standard" for sleep data collection but when compared to polysomnographies are more affordable and accessible to patients. Because of their compact design, actigraphies collect sleep tracking data over a longer period of time from patients without requiring their patients to make major changes to their day-to-day routine or their sleeping environment. The downsides of actigraphs are that they cannot track sleep staging, the storage of data collected on the device is limited, actigraphy devices are still expensive (around $1,000), and a specialist still needs to analyze the data collected from the devices to determine if there are any issues with the device's data collection.
Consumer devices
People can track their sleep through smartphones with consumer sleep-tracking apps, wearable devices, or a combination or both consumer sleep-tracking apps and wearable devices. Consumer sleep-tracking devices such as smartphones and activity trackers were developed primarily for the use of consumers, not for clinical use or research.
In contrast to polysomonographies and actigraphies, smartphones may be easier for people to utilize for sleep tracking purposes as they may already use smartphones in their day-to-day lives. Smartphones also have built-in motion-sensing accelerometers and microphone features and cloud storage. Wearable consumer-sleep tracking devices have been noted to have issues with lost or unusable data due to technical or software issues.
The utilization of consumer sleep-tracking devices for clinical data collection has become more widely accepted by healthcare providers because these devices are more affordable and practical compared to polysomnographies and actigraphies. However, consumer sleep-tracking devices still have a long way to go before they produce accurate and reliable sleep-tracking information for the utilization of sleep disorder and mental illness treatment, research, and diagnoses. The motion sensors in smartphones and smartwatches are not medical-grade, smartphone data alone is not enough to capture the full picture of a patient's sleep staging, and data collected from consumer sleep-tracking devices are not reliable enough as monitoring tools as they tended to over or under-estimate data such as total sleep time.
There is also a concern among health professionals that consumer sleep-tracking devices and applications may encourage consumers to self-diagnose in reaction to the results of their sleep grade, quality of sleep, or recorded hours of sleep from their consumer sleep-tracking device. Even though the average adult needs between seven and nine hours of sleep, a consumer sleep-tracking device may encourage all of their consumers to strive for eight hours of sleep in order to get a good sleep grade. This can result in consumers feeling anxious over the amount of sleep they get each night and cause them to change their sleeping behaviors in order to improve their sleep according to the consumer sleep-tracking device's algorithm. Additionally, consumers may feel content with the findings of their consumer sleep-tracking devices and forgo seeking professional help.
In one study conducted by Rush University Medical College and Northwestern University’s Feinberg School of Medicine, three patients who reported having unsatisfying sleep or experiencing sleep abnormalities were utilizing consumer sleep-tracking devices before seeking professional help from sleep therapists. In the study, two patients were not satisfied with the findings or recommendations of the sleep therapists and did not return for a follow-up visit, citing that the recommendations of the sleep therapists did not correspond with the findings of the consumer sleep-tracking device. The one patient who did return for follow-up visits and followed the recommendations of the sleep therapists, which included switching his device from sensitive mode to normal mode and decreasing his hypnotic medication, was reportedly pleased with the progress made in his sleep quality.
See also
Actigraphy
Activity tracker
Polysomnography
References
Sleep
Health
Tracking | Sleep tracking | [
"Technology",
"Biology"
] | 2,049 | [
"Tracking",
"Behavior",
"Sleep",
"Wireless locating"
] |
66,216,122 | https://en.wikipedia.org/wiki/Marie%20U.%20Nylen | Marie Ussing Nylen is a Danish-American biologist, dentist, microscopist, and badminton player known for her research on the morphology of tooth enamel and her contributions to refining the electron microscope as an aide in dental research at the National Institute of Dental and Craniofacial Research (NIDR). She was the first woman director of the NIDR's Intramural Research Program. Nylen became director of the NIDR extramural research program in 1984. In 1947 and 1953, she won the women's world singles event at the All England Open Badminton Championship.
Education
Nylen is from Denmark. She completed a D.D.S. at the Royal Dental College, University of Copenhagen (Danish language reference) in 1947. Nylen first came to the United States from her native Denmark in the summer of 1949 on a two-month visit to a friend in Washington, DC. During her stay she called on one of her former professors from the Royal Dental College of the University of Copenhagen, who at that time was a visiting scientist here in the National Institute of Dental Research (NIDR). He interested her in the possibility of obtaining special training at NIH. As a result, she applied for and received a postdoctoral fellowship in dentistry from NIDR and trained here from 1950 to 1951 in the use of electron microscopy and diffraction in studies of calcified tissues of the mouth. Among her early contributions to this new and unique field of dental research was the perfection of a modified microtome capable of producing high quality ultrathin sections of dental tissues for electron microscope study. Development of this instrument, capable of cutting sections 1/50,000 of a mm. in thickness, permitted the study of hitherto unobserved structures of cells which form enamel and dentin.
Career
After her year at NIH, Nylen returned to Copenhagen where she was an assistant professor in oral diagnosis at her alma mater for two years. In 1955, she came back to Bethesda to join the staff of NIDR's laboratory of histology and pathology. In 1965, Nylen became chief of NIDR's laboratory of biological structure. In July 1977, she became the first woman director of NIDR intramural research. She succeeded acting director Wallace D. Armstrong.
In 1984, Nylen became associate director of the NIDR extramural program, succeeding John F. Goggins. Abner L. Notkins replaced Nylen as acting intramural director. In her new position, Nylen administered the institute's extramural program. This component consisted of three categorical branches which fund research in periodontal and soft tissue diseases, craniofacial anomalies, pain control and behavior, and caries and restorative materials.
She was an associate editor of the Scandinavian Journal of Dental Research and Oral Sciences Reviews, a member of the advisory editorial boards of Calcified Tissue Research and Acta Odontologica Scandinavica, and a member of the publications committee, Journal of Dental Research. She served for 4 years as a member of the NIH Oral Biology and Medicine Study Section, reviewing NIDR research grant applications, and more recently as a member of the Caries Executive Committee, reviewing contract proposals for the institute's National Caries Program.
Research
Nylen was known for her research on the morphology of tooth enamel and her contributions to refining the electron microscope as an aide in dental research. By 1960, Nylen was recognized for her the production and maturation of the organic matrices of enamel and dentin. Her work in this field led to the publication of an atlas, reporting one of the first embryological studies of dental tissues made at the electron microscope level. Because of its breadth and systematic approach to an understanding of dental histogenesis, this publication has been well received by teachers both in the U.S. and abroad. Other technical advances associated with Nylen's work have included important techniques for the preparation and imbedding of specimens for electron microscopy and specimen preparation for microradiography. She has also contributed to the scientific literature in related areas, including basic studies of the mechanism of mineralization, using other calcifying systems such as tendon, reconstituted collagen, and calculus.
Nylen's dental studies have added to scientific knowledge in areas such as the ultrastructural morphology of teeth and bones, and the calcification of tissue. Her findings of the effects of tetracycline on dental enamel of experimental animals contributed to restrictions on the use of this antibiotic in humans. She is also being cited for her administrative abilities.
Badminton
Nylen was four times co-winner of the women's doubles championship of Denmark, and in 1947 and 1953, she won the women's world singles event at the All England Open Badminton Championship. She was women's badminton champion of DC in 1950 and 1951 and also won the New England championship in 1951. As of August 1960, Nylen was an active member of the DC Badminton Club.
Medal Record at the All England Badminton Championships
Personal life
Marie Ussing was born on 13 April 1924 in Copenhagen, Denmark, the daughter of Henry Ussing (Danish language reference), professor of law, University of Copenhagen and wife Christiane Johanne Ussing (born Nyebølle). When she returned to NIH in 1955 she settled in Washington, DC with her husband Aage Nylén, a former Norwegian citizen. Aage Nylén was vice president of the hospitality division of Guest Services Inc., a quasi-public firm that operates government cafeterias and recreational facilities. Before joining GSI, he was associated with the Marriott Corp., the Shoreham Hotel and the Statler-Hilton (now the Capital Hilton). He had also been managing director of The Madison hotel.
They had a daughter and two sons, Ingrid Nylén, Erik Nylén and Thomas Nylén. Nylen became a U.S. citizen in May 1959. In 1966 the family moved to Bethesda. Nylen took up golf and became an accomplished player. She also enjoys playing contract bridge.
Awards and honors
Nylen won the 1970 International Association for Dental Research (IADR)'s annual award for basic research in biological mineralization. The award was sponsored by Lever Brothers. Nylen was given the honorary degree of Doctor Odontologiae by her alma mater in 1973. Other honors include the Superior Service Honor Award of the US Department of Health, Education, and Welfare. On December 3, 1975, Nylen was 1 of 6 who presented with the Federal Woman's Award from the International Association for Dental Research for her contribution to the field of crystallization and mineralization. She was a fellow of the American College of Dentists. In 1979, Nylen received a DHEW Distinguished Service award, the highest departmental honorary recognition conferred on civilian employees. She received an honorary degree of Doctor of Science from Georgetown University. Nylen has served as president for both the American Association for Dental Research and the IADR, in both organizations the first woman to serve as president.
References
20th-century American women scientists
20th-century Danish biologists
Danish emigrants to the United States
20th-century American dentists
Danish dentists
American women dentists
American medical researchers
Women medical researchers
Danish medical researchers
Microscopists
National Institutes of Health people
Date of birth missing
Date of death missing
Place of birth missing
Danish women scientists
American women biologists
20th-century American biologists
Danish female badminton players
American female badminton players | Marie U. Nylen | [
"Chemistry"
] | 1,530 | [
"Microscopists",
"Microscopy"
] |
66,216,426 | https://en.wikipedia.org/wiki/RKI-1447 | RKI-1447 is a drug which acts as a potent and selective inhibitor of the enzyme Rho kinase, with an IC50 of 14.5 nM at ROCK1 and 6.2 nM at ROCK2. It has been investigated for applications in cancer treatment, as well as glaucoma, and nonalcoholic fatty liver disease.
See also
Rho kinase inhibitor
References
Enzyme inhibitors
Thiazoles
4-Pyridyl compounds
3-Hydroxyphenyl compounds
Ureas | RKI-1447 | [
"Chemistry"
] | 105 | [
"Pharmacology",
"Medicinal chemistry stubs",
"Organic compounds",
"Pharmacology stubs",
"Ureas"
] |
66,216,565 | https://en.wikipedia.org/wiki/Verosudil | Verosudil (AR-12286) is a drug which acts as a potent and selective inhibitor of the enzyme Rho kinase, and has been investigated for the treatment of glaucoma.
See also
Rho kinase inhibitor
References
Enzyme inhibitors
Isoquinolines
Thiophenes
Amides
Amines | Verosudil | [
"Chemistry"
] | 64 | [
"Pharmacology",
"Pharmacology stubs",
"Functional groups",
"Medicinal chemistry stubs",
"Amines",
"Amides",
"Bases (chemistry)"
] |
66,216,612 | https://en.wikipedia.org/wiki/Orthosomnia | Orthosomnia is a medical term for an unhealthy obsession with getting perfect sleep. The term was coined by researchers from Rush University Medical College and Northwestern University’s Feinberg School of Medicine in a case study published on February 15, 2017 in the Journal of Clinical Sleep Medicine titled "Orthosomnia: Are Some Patients Taking the Quantified Self Too Far?" in which the researchers noticed that the three patients having their sleep tracked spent excessive time in bed in order to increase their "sleep numbers", which might have actually made their Insomnia worse.
Dr. Sabra Abbott, an assistant professor of neurology at Northwestern University and one of the researchers involved in the study, first noticed Orthosomnia when she and her colleagues started having "a number of patients coming in with a phenomenon that didn't necessarily meet the classical description of insomnia, but that was still keeping them up at night". Abbott also noticed that because the people suffering from Orthosomnia became so dependent on their sleep tracking devices, "they were actually destroying their sleep" because they weren't measuring up to what their tracker considered a "good" amount of sleep.
See also
Orthorexia nervosa
References
Sleep disorders | Orthosomnia | [
"Biology"
] | 260 | [
"Behavior",
"Sleep",
"Sleep disorders"
] |
66,216,691 | https://en.wikipedia.org/wiki/Revolution%20Max | The Revolution Max is a V-twin motorcycle engine from Harley-Davidson. It features double overhead camshafts and liquid cooling. It debuted in the Pan America adventure bike in February 2021. Harley-Davidson has announced this engine will eventually come in sizes ranging from 500cc to 1250cc. A variant of the Revolution Max called the 1250T saw use in the Sportster S, the first motorcycle under the Sportster nameplate to receive a new engine since 1986.
A 975cc version of the engine was announced for an upcoming streetfighter motorcycle called the Bronx, but that bike has been put on hold and may be cancelled. However, the engine was eventually introduced in the Nightster in 2022.
References
Harley-Davidson engines
Motorcycle engines | Revolution Max | [
"Technology"
] | 152 | [
"Motorcycle engines",
"Engines"
] |
66,216,792 | https://en.wikipedia.org/wiki/Thiazovivin | Thiazovivin is a drug which acts as a potent and selective inhibitor of the enzyme Rho kinase. It is used alongside a cocktail of other growth factors and modulators in cell culture techniques for the generation of induced pluripotent stem cells, which can then be used for a wide variety of applications.
See also
Rho kinase inhibitor
References
Enzyme inhibitors
Thiazoles
Pyrimidines
Amides
Amines | Thiazovivin | [
"Chemistry"
] | 89 | [
"Pharmacology",
"Functional groups",
"Medicinal chemistry stubs",
"Amines",
"Pharmacology stubs",
"Amides",
"Bases (chemistry)"
] |
66,217,765 | https://en.wikipedia.org/wiki/Virgil%20Boekelheide | Virgil Boekelheide (28 July 1919 – 24 September 2003) was an American organic chemist and a professor in the department of chemistry at the University of Oregon. He is known for his work on aromatic compounds, particularly cyclophanes, and a name reaction, the Boekelheide reaction, is named after him.
Education and academic career
Boekelheide was born in Chelsea, South Dakota to a family of German ancestry. He received his bachelor's degree from Dakota Wesleyan University in 1939. He then received his PhD from the University of Minnesota in 1943, where he worked under the supervision of C. Frederick Koelsch. After three years as an instructor at the University of Illinois, he joined the faculty as a professor at the University of Rochester in 1946. He moved to the University of Oregon in 1960 and remained there for the rest of his research career. He retired in 1984.
Boekelheide was awarded the Guggenheim Fellowship in 1953 and was an Alexander von Humboldt Fellow, permitting him to spend time as a visiting scientist in Germany. He was elected to the United States National Academy of Sciences in 1962.
Research
Boekelheide began his research career studying alkaloid natural products, but later refocused his interests on aromaticity, particularly bridged compounds known as cyclophanes. He was the first to synthesize the sixfold-bridged cyclophane compound known as superphane, a molecule of interest due to its unique pi-stacking intramolecular interactions.
A name reaction, the Boekelheide reaction, is named after him following his publication in 1954.
Personal life
Especially in later life, Boekelheide was a patron of the arts in Eugene, Oregon, serving as president of the Eugene Ballet Society from 1988 to 1991. He and his wife had three children.
References
American organic chemists
1919 births
2003 deaths
Members of the United States National Academy of Sciences
Dakota Wesleyan University alumni
University of Minnesota alumni
University of Illinois faculty
University of Rochester faculty
University of Oregon faculty
American expatriates in Germany | Virgil Boekelheide | [
"Chemistry"
] | 427 | [
"Organic chemists",
"American organic chemists"
] |
66,219,272 | https://en.wikipedia.org/wiki/Weld%20tests%20for%20friction%20welding | Quality requirements of welded joints depend on the form of application, e.g. in the space or fly industry weld errors are not allowed. Science try to gets good quality welds. There are many scientific articles describing the weld test, e.g. hardness, tensile tests. The weld structure can be examined by optical microscopy and scanning electron microscopy. The computer finite element method (FEM) is used to predict the shape of the flash and interface and others, not only for rotary friction welding (RFW), but also for friction stir welding (FSW), linear friction welding (LFW), FRIEX, and others. Temperature measurements are also carried out for scientific purposes e.g. by use thermocouples or sometimes thermography, mentions about measurements are generally found in research materials and journals.
See also
Friction welding
Temperature
Heat-affected zone
Weld quality assurance
References
Nondestructive testing
Quality control
Welding | Weld tests for friction welding | [
"Materials_science",
"Engineering"
] | 198 | [
"Nondestructive testing",
"Materials testing",
"Welding",
"Mechanical engineering"
] |
66,220,637 | https://en.wikipedia.org/wiki/Cortinarius%20aurae | Cortinarius aurae is a little brown mushroom found in Europe and North America, originally described from a UK specimen in 2020. It was named in honour of the describing authors' new born daughter. Along with five other British webcaps, C. aurae was selected by Kew Gardens as a highlight of taxa described by the organisation's staff and affiliates in 2020.
Taxonomy
Cortinarius aurae was described in a 2020 research note in the journal Fungal Diversity by Kare Liimatainen and Tuula Niskanen. The description was based on a collection made by Liimatainen in 2015 in the Black Wood of Rannoch, Perthshire, Scotland. The species was named after the authors' newborn daughter, Aura. Phylogenetic analysis placed the species in Cortinarius sect. Obtusi.
Cortinarius aurae was one of over 150 botanical and mycological taxa described by staff or affiliates of Kew Gardens in 2020. In a year-end round-up, Kew scientists selected ten highlights, one of which was six newly described British Cortinarius species: C. scoticus and C. aurae from the Black Wood of Rannoch; C. britannicus described from Caithness; C. subsaniosus from Cumbria; C. ainsworthii from Brighton; and C. heatherae from Heathrow Airport. In a press release, Kew identified Cortinarius species as "ecologically important in supporting the growth of plants, particularly trees such as oak, beech, birch and pine" and playing "a key role in the carbon cycling of woodlands and providing nitrogen to trees".
Description
Cortinarius aurae mushrooms have a red-brown, conical to somewhat convex cap that is wide. The cap is hygrophanous, and often has an umbo. The yellowish brown gills are medium spaced. The stem is long and thick. It is cylindrical, and the base can push into the substrate. When the mushroom is young, the stem is covered in white fibrils; older mushrooms have yellowish brown stems. The stem has a white, sparse universal veil. The flesh is brown. At the base of the stem, there is a weak iodoform-like odour (especially in slightly dried mushrooms), but there is no distinct smell on the gills.
Microscopic characteristics
Cortinarius aurae basidiospores measure 6.5 to 8 by 4.5 to 5.5 micrometres (μm), averaging 7.0 by 4.7 μm. They are generally ellipsoid, but sometimes almond-shaped. They are moderately warty, and fairly dextrinoid, meaning that they turn reddish to reddish-brown when stained with Melzer's reagent or Lugol's solution. The basidia measure 24 to 32 by 7 9.5 μm. They are club-shaped, with four sterigmata. The hyphae in the flesh of the gills are golden brown, strongly encrusted with zebra-striped encrustations. The pileipellis surface is pale, consisting of more or less parallel hyphae 8 to 13 μm wide that are densely encrusted with zebra-striped incrustations. Below the surface, the cells are pale
orange-brown, measuring 15.5 to 47 by 10 to 23 μm, and are densely encrusted with zebra-striped incrustations.
Similar species
Cortinarius aurae is most reminiscent of C. obtusus, but the latter has somewhat larger (8 to 9 by 4.5 to 5 μm), almond-shaped spores.
Ecology
Cortinarius aurae is found in mesic to damp coniferous forests, but also known to occur with sweet chestnut (Castanea sativa). The species is widespread, being known from both Europe and North America.
References
aurae
Fungi described in 2020
Fungi of Europe
Fungi of North America
Fungus species | Cortinarius aurae | [
"Biology"
] | 825 | [
"Fungi",
"Fungus species"
] |
66,221,186 | https://en.wikipedia.org/wiki/Representations%20of%20classical%20Lie%20groups | In mathematics, the finite-dimensional representations of the complex classical Lie groups
, , , , ,
can be constructed using the general representation theory of semisimple Lie algebras. The groups
, , are indeed simple Lie groups, and their finite-dimensional representations coincide with those of their maximal compact subgroups, respectively , , . In the classification of simple Lie algebras, the corresponding algebras are
However, since the complex classical Lie groups are linear groups, their representations are tensor representations. Each irreducible representation is labelled by a Young diagram, which encodes its structure and properties.
General linear group, special linear group and unitary group
Weyl's construction of tensor representations
Let be the defining representation of the general linear group . Tensor representations are the subrepresentations of (these are sometimes called polynomial representations). The irreducible subrepresentations of are the images of by Schur functors associated to integer partitions of into at most integers, i.e. to Young diagrams of size with . (If then .) Schur functors are defined using Young symmetrizers of the symmetric group , which acts naturally on . We write .
The dimensions of these irreducible representations are
where is the hook length of the cell in the Young diagram .
The first formula for the dimension is a special case of a formula that gives the characters of representations in terms of Schur polynomials, where are the eigenvalues of .
The second formula for the dimension is sometimes called Stanley's hook content formula.
Examples of tensor representations:
General irreducible representations
Not all irreducible representations of are tensor representations. In general, irreducible representations of are mixed tensor representations, i.e. subrepresentations of , where is the dual representation of (these are sometimes called rational representations). In the end, the set of irreducible representations of is labeled by non increasing sequences of integers .
If , we can associate to the pair of Young tableaux . This shows that irreducible representations of can be labeled by pairs of Young tableaux . Let us denote the irreducible representation of corresponding to the pair or equivalently to the sequence . With these notations,
For , denoting the one-dimensional representation in which acts by , . If is large enough that , this gives an explicit description of in terms of a Schur functor.
The dimension of where is
where . See for an interpretation as a product of n-dependent factors divided by products of hook lengths.
Case of the special linear group
Two representations of are equivalent as representations of the special linear group if and only if there is such that . For instance, the determinant representation is trivial in , i.e. it is equivalent to .
In particular, irreducible representations of can be indexed by Young tableaux, and are all tensor representations (not mixed).
Case of the unitary group
The unitary group is the maximal compact subgroup of . The complexification of its Lie algebra is the algebra . In Lie theoretic terms, is the compact real form of , which means that complex linear, continuous irreducible representations of the latter are in one-to-one correspondence with complex linear, algebraic irreps of the former, via the inclusion .
Tensor products
Tensor products of finite-dimensional representations of are given by the following formula:
where unless and . Calling the number of lines in a tableau, if , then
where the natural integers are
Littlewood-Richardson coefficients.
Below are a few examples of such tensor products:
In the case of tensor representations, 3-j symbols and 6-j symbols are known.
Orthogonal group and special orthogonal group
In addition to the Lie group representations described here, the orthogonal group and special orthogonal group have spin representations, which are projective representations of these groups, i.e. representations of their universal covering groups.
Construction of representations
Since is a subgroup of , any irreducible representation of is also a representation of , which may however not be irreducible. In order for a tensor representation of to be irreducible, the tensors must be traceless.
Irreducible representations of are parametrized by a subset of the Young diagrams associated to irreducible representations of : the diagrams such that the sum of the lengths of the first two columns is at most . The irreducible representation that corresponds to such a diagram is a subrepresentation of the corresponding representation . For example, in the case of symmetric tensors,
Case of the special orthogonal group
The antisymmetric tensor is a one-dimensional representation of , which is trivial for . Then where is obtained from by acting on the length of the first column as .
For odd, the irreducible representations of are parametrized by Young diagrams with rows.
For even, is still irreducible as an representation if , but it reduces to a sum of two inequivalent representations if .
For example, the irreducible representations of correspond to Young diagrams of the types . The irreducible representations of correspond to , and .
On the other hand, the dimensions of the spin representations of are even integers.
Dimensions
The dimensions of irreducible representations of are given by a formula that depends on the parity of :
There is also an expression as a factorized polynomial in :
where are respectively row lengths, column lengths and hook lengths. In particular, antisymmetric representations have the same dimensions as their counterparts, , but symmetric representations do not,
Tensor products
In the stable range , the tensor product multiplicities that appear in the tensor product decomposition are Newell-Littlewood numbers, which do not depend on . Beyond the stable range, the tensor product multiplicities become -dependent modifications of the Newell-Littlewood numbers. For example, for , we have
Branching rules from the general linear group
Since the orthogonal group is a subgroup of the general linear group, representations of can be decomposed into representations of . The decomposition of a tensor representation is given in terms of Littlewood-Richardson coefficients by the Littlewood restriction rule
where is a partition into even integers. The rule is valid in the stable range . The generalization to mixed tensor representations is
Similar branching rules can be written for the symplectic group.
Symplectic group
Representations
The finite-dimensional irreducible representations of the symplectic group are parametrized by Young diagrams with at most rows. The dimension of the corresponding representation is
There is also an expression as a factorized polynomial in :
Tensor products
Just like in the case of the orthogonal group, tensor product multiplicities are given by Newell-Littlewood numbers in the stable range, and modifications thereof beyond the stable range.
External links
Lie online service, an online interface to the Lie software.
References
Representation theory of Lie groups
Lie groups | Representations of classical Lie groups | [
"Mathematics"
] | 1,376 | [
"Lie groups",
"Mathematical structures",
"Algebraic structures"
] |
66,221,860 | https://en.wikipedia.org/wiki/Cortinarius%20scoticus | Cortinarius scoticus is a little brown mushroom known from central and northern Europe, where it grows in pine forests. It was described in 2020, and named for Scotland, where it was first found. Along with five other British webcaps, C. scoticus was selected by Kew Gardens as a highlight of taxa described by the organisation's staff and affiliates in 2020.
Taxonomy
Cortinarius scoticus was described in a 2020 research note in the journal Fungal Diversity by Tuula Niskanen and Kare Liimatainen. The description was based on a collection made by Niskanen in 2015 in the Black Wood of Rannoch, Perthshire, Scotland, and the species was named after the holotype's country of origin. Phylogenetic analysis placed the species in Cortinarius sect. Obtusi. The species shares a number of identifying features with other members of the section, namely: the weak, iodoform-like, odour at the base of the stipe; the white and sparse universal veil; and small, brown fruiting bodies.
Cortinarius scoticus was one of over 150 botanical and mycological taxa described by staff or affiliates of Kew Gardens in 2020. In a year-end round-up, Kew scientists selected ten highlights, one of which was six newly described British Cortinarius species: C. scoticus and C. aurae from the Black Wood of Rannoch; C. britannicus described from Caithness; C. subsaniosus from Cumbria; C. ainsworthii from Brighton; and C. heatherae from Heathrow Airport. In a press release, Kew identified Cortinarius species as "ecologically important in supporting the growth of plants, particularly trees such as oak, beech, birch and pine" and playing "a key role in the carbon cycling of woodlands and providing nitrogen to trees".
Description
Cortinarius scoticus mushrooms have caps that are wide. They are hemispherical, maturing to a low convex or almost flat. The caps are red brown to dark red brown, and hygrophanous. The gills are brown and medium spaced. The stem is long and thick. The stems are cylindrical. When young, they are covered with silky, white fibrils, though they mature to yellowish brown. The flesh is brown. At the base of the stem, it has a weak, iodoform-like, smell that is best observed when the mushroom is slightly dried. In the gills, however, the scent is indistinct. The stem has a sparse, white, universal veil.
Microscopic characteristics
Cortinarius scoticus has basidiospores measuring 7.5 to 8.8 by 4.5 to 5.5 micrometres (μm). The spores are ellipsoid to somewhat almond-shaped, and moderately warty. They are fairly dextrinoid, meaning that they stain reddish to reddish-brown when Melzer's reagent or Lugol's solution is applied. The basidia are 25 to 34 by 7 to 10 μm. They are club-shaped, with four sterigmata. The hyphae in the flesh of the gills are yellowish brown, fairly strongly encrusted with zebra-striped encrustations. The surface of the pileipellis is pale, consisting of more or less parallel hyphae, 5 μm wide, without encrustations. Lower cells in the pileipellis are 19 to 44 by 10 to 20 μm. Some of these hyphae are encrusted with zebra-like incrustations.
Similar species
In the field, C. scoticus looks like C. trossingenensis, but the latter has small (4.5 to 5.5 by 4 to 4.5 μm), subglobose (nearly or imperfectly globe-shaped) spores.
Ecology
Cortinarius scoticus is found in mesic and damp pine-dominated forests. It is known from central and northern Europe.
References
scoticus
Fungi described in 2020
Fungi of Europe
Fungus species | Cortinarius scoticus | [
"Biology"
] | 866 | [
"Fungi",
"Fungus species"
] |
66,222,662 | https://en.wikipedia.org/wiki/Xiaomi%20Mi%2011 | The Xiaomi Mi 11 is an Android-based high-end smartphone designed and marketed by Xiaomi Inc. succeeding their Xiaomi Mi 10 series. The phone was launched globally on 8 February 2021.
Hardware
Design
The design of the Xiaomi Mi 11 is similar to the Mi 10, maintaining the front camera design in the upper left corner. The Mi 11 uses Corning Gorilla Glass Victus on its display and Corning Gorilla Glass 5, or vegan leather, on its back. The front of the phone uses a hidden earpiece. The back of the phone has two material designs and five available colours: black, white, blue, smokey purple, and brown. The first three use anti-glare glass and the latter two use vegan leather. Due to the varying materials, the thickness and weight of the device are also different. The anti-glare frosted glass version is 8.06 mm thick and weighs 196 g, and the vegan leather version is 8.56 mm thick and weighs 194 g.
The side frame of the Mi 11 is made of an aluminum alloy, and there is a communication antenna overflow band around the fuselage, which is plastic injection molded with a colour similar to the frame. The upper part of the frame is equipped with a noise-reduction microphone, an infrared emission window, and a top sub-speaker (integrated earpiece function). The right side is equipped with plus and minus volume buttons and a switch screen/power button. The lower part is equipped with a SIM card slot and ejection jack, a USB Type-C interface, and the main speaker openings. The frame is slightly wider near the control buttons.
The back of the Mi 11 is made of AG-processed glass or leather-like polycarbonate plastic. The glass-based version of the back cover is about 2 g heavier than the polycarbonate version, but the total thickness is reduced by 0.5 mm. The upper left corner of the back cover contains the rear camera group area, which is contained in a rounded rectangle. The left side of the camera area is a Nascar racetrack-shaped black area, with the main camera sensor placed on the upper part and the wide-angle sensor on the lower part. There is a bright silver ring on the periphery of the main camera sensor opening, which is slightly protruding and is similar to the design of Mi 9, Mi CC9 and other models. The right side of the racetrack-shaped area is a silver area; from top to bottom, the long-focus macro sensor, LED fill light and auxiliary ambient light sensor are arranged. In the lower-left corner of the fuselage, the "XIAOMI" logo of the Xiaomi Group, which is the same as the Xiaomi CC9 series, replaces the previous "MI" logo. The plain leather version also has a metal circular decoration under the logo, which also serves as a fixed leather laminate.
Screen
The Xiaomi Mi 11 uses a flexible AMOLED display provided by Samsung Display, which is Samsung's fourth-generation AMOLED substrate (E4). It has a diamond-shaped sub-pixel arrangement and has a resolution of 3200 by 1440. The pixel density (PPI) is 515. It supports up to 1771nit of peak brightness and 996nit of full-screen brightness, as tested by Display Mate, and supports DCI-P3 color gamut.
The screen glass of Xiaomi Mi 11 uses Corning Gorilla Glass Victus.
Chip and Storage
The Mi 11 uses the Qualcomm Snapdragon 888 SoC.
The CPU houses the Qualcomm Kryo 680 architecture, consisting of a large core with a main frequency of 2.84 GHz, three middle cores with a main frequency of 2.42 GHz, and four small cores of 1.8 GHz. The chip integrates an Adreno 660 GPU with a main frequency of 840 MHz It supports dual 5G SIM cards while staying on standby under the 5G network.
The device encapsulates 8GB or 12GB of LPDDR5 RAM above the SoC, with a main frequency of 3200 MHz, and optional storage of 128GB or 256GB. The specifications are all UFS 3.1, which is consistent with the Mi 10 Extreme Commemorative Edition.
Camera
For the rear camera, the Mi 11 uses the Samsung Bright S5KHMX sensor that was used in some older models, with a 108MP resolution and an aperture of f/1.85. In addition to acting as the main camera in the Mi 11, it also supports up to 30x digital zoom through cropping. Mi 11 output photo pixels are similar to the Mi 10, with 27 million pixels (pixel-binned 108-megapixel images). It can record video at 720P 30fps, 1080P 30/60fps, 4K 30/60fps, and AI 8K 24/30fps. In addition to normal video, it can also record interpolated slow-motion at 720P 120/480fps and 1080P 120/480fps.
The Xiaomi Mi 11 is also equipped with a 13-megapixel ultra-wide-angle sensor (supplied by Omnivision Technologies, OV13B10), which supports wide-angle shooting up to 123°, an aperture of f/2.4, and can record video at 720P 30fps, 1080P 30/60fps, and 4K 30fps.
The device also sports a 5-megapixel telephoto macro camera (supplied by Samsung, S5K5E9) which has a focusing range of 10-3cm from the subject. This sensor is also able to record video at 720P 30fps and 1080P 30fps.
The front camera of the Mi 11 uses the Samsung S5K3T2 sensor, which is also used in the Xiaomi Mi 10 series and Redmi K20/30 series, with a pixel count of 20 million. It supports 1080P 30/60fps and 720P 30fps video recording.
Other
The Mi 11 supports wired charging with a power of up to 55W (11V 5A MAX), wireless charging with a power of 50W, and reverse wireless charging with a power of up to 10W, which can charge other devices that support wireless charging. However, the Chinese version of the Mi 11 does not come with a charger. In certain regions, the standard version arrives with no charger, but a version with a 55 W GaN charger is also available at no extra cost. The global version comes with a 55W GaN charger, charging cable, plastic screen protector, translucent plastic case, and SIM ejector tool in the box.
The phone uses stereo speakers, but the symmetrical stereo speakers used on the Mi 10 have been changed to asymmetrical stereo speakers. The top sound unit is slightly smaller than the bottom and also functions as an earpiece. In addition, the 3.5mm audio output and input interface have been removed. The 3.5mm standard connector can only be converted using a USB Type-C to 3.5mm audio cable conversion cable.
The phone also supports Bluetooth 5.2, multi-function NFC, and infrared remote control functions. Remote control apps can control electrical equipment that supports infrared control.
Software
Xiaomi Mi 11 uses the MIUI 12 operating system based on Android 11.
Mi 11 Ultra / Mi 11 Pro / Mi 11 Lite 5G and Mi 11 Lite / Xiaomi 11 Lite 5G NE
Along with the Mi 11, Xiaomi also released the Mi 11 Ultra and Mi 11 Pro in China on 29 March 2021 and globally in April 2021. Alongside those, Xiaomi also launched Mi 11 Lite 5G and Mi 11 Lite, and the Xiaomi 11 Lite 5G NE due to chip shortages.
Mi 11 Ultra and Mi 11 Pro are the higher flagship variants, which use Qualcomm Snapdragon 888 chipset and are the first devices to come with silicon-oxygen anode battery. The Mi 11 Lite uses Snapdragon 732G, Mi 11 Lite 5G has Snapdragon 780G, and the Xiaomi 11 Lite 5G NE has Snapdragon 778G. All of these Lite phones are the thinnest smartphones of that year. Mi 11 Ultra also comes with a secondary display at the back.
References
External links
Android (operating system) devices
Phablets
Mobile phones with multiple rear cameras
Mobile phones with 8K video recording
Mobile phones with infrared transmitter
Mobile phones introduced in 2021
Discontinued flagship smartphones
Xiaomi smartphones | Xiaomi Mi 11 | [
"Technology"
] | 1,791 | [
"Crossover devices",
"Discontinued flagship smartphones",
"Phablets",
"Flagship smartphones"
] |
66,223,187 | https://en.wikipedia.org/wiki/Coleoptera%20paleobiota%20of%20Burmese%20amber | Burmese amber is fossil resin dating to the early Late Cretaceous Cenomanian age recovered from deposits in the Hukawng Valley of northern Myanmar. It is known for being one of the most diverse Cretaceous age amber paleobiotas, containing rich arthropod fossils, along with uncommon vertebrate fossils and even rare marine inclusions. A mostly complete list of all taxa described up to the end of 2023 can be found in Ross (2024).
This article covers fossils classified as belonging to order Coleoptera, and its sub-orders Adephaga, Archostemata, Myxophaga, and Polyphaga.
Adephaga
Archostemata
Myxophaga
Polyphaga
Incertae sedis
References
Prehistoric fauna by locality | Coleoptera paleobiota of Burmese amber | [
"Biology"
] | 161 | [
"Prehistoric fauna by locality",
"Prehistoric biotas"
] |
66,223,586 | https://en.wikipedia.org/wiki/Big%20Blue%20Ocean%20Cleanup | Big Blue Ocean Cleanup (est. in 2018) is an international nonprofit environmental organization with offices in York (UK), Vancouver (Canada), Kuala Lumpur (Malaysia), and Sydney (Australia). It is focused on cleaning beaches and the oceans, protecting wildlife, ocean research and innovative technologies development.
History
Big Blue Ocean Cleanup was established on 27 February 2018, by Rory Sinclair.
In March 2019, it supported the “Cash for trash” initiative, launched by an APEM freshwater consultancy.
On 22 April 2020 (the Earth Day), Big Blue Ocean Cleanup was featured in Zac Efron’s documentary The Great Global Clean Up, aired on Discovery Channel. In May 2020, Big Blue Ocean Cleanup’s volunteers were involved in removing the remainants of a large fin whale from the Clacton-on-Sea beach in Essex. In September 2020, the organization partnered with the team of Scottish rowers on their Northwest Passage expedition, planned for 2021. Team members will to collect data for the Big Blue Ocean Cleanup, including micro plastic content in the water.
Initiatives
Beaches cleanup
Cleaning up beaches is the main activity of Big Blue Ocean Cleanup. These events are being organized by the non-profit ambassadors and involve various communities, from company workers to students, to local volunteers.
"Ocean Savior" project
In October 2018, Big Blue Ocean Cleanup’s experts supported Ocean Saviour project, an initiative of Richard W. Roberts and Simon White, founders of TheYachtMarket.com, to build self-powering 70m tri-deck clean-up vessel, which will retrieve and recycle plastic from the ocean.
Sponsors
The non-profit is supported mainly by small and medium-sized enterprises (some examples being search-engine Ekoru, Subsea Expo, provider of marine engineering services James Fisher & Sons and packaging supplier Storopack).
References
External links
Plastics and the environment
Organisations based in York
Environmental organizations established in 2018
Ocean pollution
Litter
Conservation and environmental foundations
Non-profit organisations based in the United Kingdom | Big Blue Ocean Cleanup | [
"Chemistry",
"Environmental_science"
] | 410 | [
"Ocean pollution",
"Water pollution"
] |
66,224,112 | https://en.wikipedia.org/wiki/Zuzanna%20S.%20Siwy | Zuzanna Stefania Siwy (born 1972) is a Polish–American chemist at the University of California, Irvine. Her research considers synthetic nanopores and their application in ionic devices. She is a Fellow of the American Physical Society, American Association for the Advancement of Science and Foundation for Polish Science.
Early life and education
Siwy is from Poland. She studied chemistry at the Silesian University of Technology in Poland. She graduated with a master's degree in polymer technology in 1995, before completing a doctorate in chemical sciences in 1997. Siwy was a postdoctoral scholar at the University of Florida.
Research and career
Siwy joined the faculty at the University of California, Irvine in 2005. In 2012 she was made Professor of Chemical Physics. She studies synthetic nanopores, which she looks to use as templates for biomimetic channels as well as ionic diodes and transistors.
Awards and honours
2000 Elected Fellow of the Foundation for Polish Science
2001 Elected Fellow of the Alexander von Humboldt Foundation
2007 Alfred P. Sloan Foundation Fellow
2008 National Science Foundation CAREER Award
2009 Friedrich Wilhelm Bessel Research Award
2009 Presidential Early Career Award for Scientists and Engineers
2012 University of California, Irvine Distinguished Mid-Career Faculty Award for Research
2013 Elected Fellow of the American Physical Society
2019 Elected Fellow of the American Association for the Advancement of Science
Selected publications
References
1972 births
Living people
American people of Polish descent
Polish women chemists
University of California, Irvine faculty
Fellows of the American Physical Society
Fellows of the American Association for the Advancement of Science
Inorganic chemists
21st-century Polish women scientists
21st-century Polish chemists
Recipients of the Presidential Early Career Award for Scientists and Engineers | Zuzanna S. Siwy | [
"Chemistry"
] | 330 | [
"Inorganic chemists"
] |
66,224,377 | https://en.wikipedia.org/wiki/Tempo%20Automation | Tempo Automation was an American electronics development and manufacturing company based in San Francisco, California.
History
Tempo was founded in 2013 by Jeff McAlvay, Jesse Koenig, and Shashank Samala. They started manufacturing customer orders through their platform in 2016.
In 2015, the company raised $8 million in Series A venture funding, led by Lux Capital. They raised $20 million in Series B funding in 2018, and an additional $45 million in Series C funding in 2019, with investors including Point72 Ventures, Lockheed Martin, and Uncork Capital, bringing their total raised to $74.6 million.
In 2018, the company opened a new factory in San Francisco to produce printed circuit boards for low-volume manufacturers and prototyping. In 2019, Joy Weiss was named president and chief executive officer, replacing founding CEO Jeff McAlvay, who became Tempo's chief process officer.
In November 2022, the company went public through a SPAC merger with ACE Convergence Acquisition Corp., raising $100 million from White Lion Capital. The company was listed on the Nasdaq stock exchange with ticker TMPO on November 23.
In July 2023, the company laid off 62 employees, leaving only 7. Their stock was delisted from Nasdaq in October 2023 after falling below the $50M market cap requirement.
References
External links
Official website
Electronics manufacturing
Printed circuit board manufacturing
Electronics companies established in 2013
Manufacturing companies based in San Francisco
2013 establishments in California | Tempo Automation | [
"Engineering"
] | 302 | [
"Electrical engineering",
"Electronic engineering",
"Printed circuit board manufacturing"
] |
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