id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
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61,090,989 | https://en.wikipedia.org/wiki/Brotopia | Brotopia: Breaking Up the Boys' Club of Silicon Valley is 2018 non-fiction book by Emily Chang. It is her debut book and was published on February 6, 2018, by Portfolio, a division of Penguin Random House. The book investigates and examines sexism and gender inequality in the technology industry of Silicon Valley.
Background
Chang drew from over two hundred interviews she conducted across the technology industry. Some of the interviews were from her work at Bloomberg, but most were original and conducted for the purposes of the book.
Publication and promotion
Vanity Fair ran an excerpt from the book in their January 2018 issue titled ""Oh My God, This Is So F---ed Up": Inside Silicon Valley's Secretive, Orgiastic Dark Side". Bloomberg Businessweek ran an excerpt in February 2018 titled "Women Once Ruled the Computer World. When Did Silicon Valley Become Brotopia?".
Brotopia was published on February 6, 2018, by Portfolio, a division of Penguin Random House.
Coverage of the book ran in The New York Times, The New York Times Book Review, San Francisco Chronicle, Financial Times, TechCrunch and The Verge.
Chang appeared on Morning Joe, Good Morning America, CBS This Morning and Marketplace to discuss the book.
The PBS Newshour-New York Times "Now Read This" book club selected Brotopia as their April 2019 book club read. Chang appeared on the PBS Newshour on April 30, 2019, and answered questions from viewers about the book.
Reception
Kirkus Reviews called the book a "thorough, important examination" of Silicon Valley, writing, "Chang's scrutiny breaks open a wide doorway, allowing fresh ideas about a tainted industry to circulate and spark discussions."
The book was longlisted for the Financial Times Business Book of the Year 2018 and the 2018 800-CEO-Read Business Books Awards, and was named one of Amazon's Best Books of the Year So Far, Tech Crunchs Best Tech Books of 2018, and Financial Times Best Books of 2018.
References
2018 non-fiction books
American non-fiction books
Books about women
Debut books
Women in technology
Portfolio (publisher) books | Brotopia | [
"Technology"
] | 440 | [
"Women in technology",
"Women in science and technology"
] |
61,090,998 | https://en.wikipedia.org/wiki/FUJIFILM%20VisualSonics | FUJIFILM VisualSonics Inc. (originally VisualSonics Inc.) is a biomedical company focused on the commercialization of high-frequency ultrasound and photoacoustic imaging equipment for research purposes. The company is headquartered in Toronto, Canada (with European headquarters in Amsterdam).
History
VisualSonics was founded in 1999 by Stuart Foster, Medical Physicist out of Sunnybrook Research Institute, Toronto. Dr. Foster's laboratory had been focused on developing a higher frequency ultrasound system since 1983 in order to better study mouse models of human disease. In 2010 the company was acquired by the American clinical ultrasound company, SonoSite Inc. (based in Bothell, WA). In 2012, FUJIFILM Holdings acquired SonoSite Inc.
References
External links
Official Website
Biomedicine
Companies based in Toronto
Medical imaging | FUJIFILM VisualSonics | [
"Biology"
] | 164 | [
"Biomedicine"
] |
61,091,011 | https://en.wikipedia.org/wiki/Taphrina%20polystichi | Taphrina polystichi is an ascomycete fungus that parasitizes Christmas fern (Polystichum acrostichoides) in eastern North America. It was described by A. J. Mix in 1938.
Taxonomy
Taphrina polystichi was described in A. J. Mix in 1938. Mix notes that the fungus was originally identified as Exoascus filicinus by Coker, though this is not listed as a synonym of the species. A molecular phylogenetic study of the genus suggested that T. polystichi and T. virginica were conspecific. However, the authors described a new species based on the strains of T. polystichi and T. virginica in a later study using molecular phylogenetics and physiology, but they did not synonymize the taxa.
Description
Taphrina polystichi causes 0.5 to 1 cm, yellowish or whitish swollen spots on leaves. Ascogenous cells are produced on both sides of the leaf, but asci are only produced on the upper leaf surface. Asci are stalked and are 30-46 by 4-8 micrometers. Ascospores are elliptic and 3-6 by 2-4 micrometers. In a trials of nitrogen utilization, T. polystichi was able to use ammonium chloride, ammonium citrate, ammonium nitrate, ammonium sulfate, magnesium nitrate, potassium nitrate, sodium nitrate, dl-alpha alanine, l-arginine, dl-aspartic acid, l-glutamic acid, dl-histidine, and dl-valine. In trials of carbon utilization, T. polystichi was able to use dextrose, sucrose, maltose, melezitose, trehalose, dextrin, inulin, and mannitol. It was unable to use lactose, rhamnose, inositol, i-erythritol, xylose, and succinic acid. The ability to use mannitol and the inability to use xylose and succinic acid distinguished it from the other species tested.
References
Taphrinomycetes
Fungal plant pathogens and diseases
Fungus species | Taphrina polystichi | [
"Biology"
] | 458 | [
"Fungi",
"Fungus species"
] |
61,091,295 | https://en.wikipedia.org/wiki/Baer%20function | Baer functions and , named after Karl Baer, are solutions of the Baer differential equation
which arises when separation of variables is applied to the Laplace equation in paraboloidal coordinates. The Baer functions are defined as the series solutions about which satisfy , . By substituting a power series Ansatz into the differential equation, formal series can be constructed for the Baer functions. For special values of and , simpler solutions may exist. For instance,
Moreover, Mathieu functions are special-case solutions of the Baer equation, since the latter reduces to the Mathieu differential equation when and , and making the change of variable .
Like the Mathieu differential equation, the Baer equation has two regular singular points (at and ), and one irregular singular point at infinity. Thus, in contrast with many other special functions of mathematical physics, Baer functions cannot in general be expressed in terms of hypergeometric functions.
The Baer wave equation is a generalization which results from separating variables in the Helmholtz equation in paraboloidal coordinates:
which reduces to the original Baer equation when .
References
Bibliography
(free online access to the appendix on Baer functions)
External links
Ordinary differential equations
Special functions | Baer function | [
"Mathematics"
] | 247 | [
"Special functions",
"Combinatorics"
] |
61,092,115 | https://en.wikipedia.org/wiki/Architectural%20icon | An architectural icon is a building considered to be groundbreaking, or to claim uniqueness because of its design.
Definition
These outstanding buildings and ensembles meet several of the following criteria:
widespread recognition
popularity
originality
symbol value
significance for the development of architecture
representative of an architectural style
Sabine Thiel-Siling writes in her preface to Architectural icons of the 20th century: "The buildings are spectacular for their time and their surroundings, whether through their constructive achievements or innovative use of materials, through their formal language or because they embodied a completely new type of building for the first time."
Some buildings have developed into pilgrimage venues for architecture enthusiasts or have even become landmarks of cities, even countries. But they have often been misunderstood by laymen, even when they have become role models for entire generations of architects.
Tom Wright, the architect of Burj al Arab said on the same subject: "How can you tell that a building has become a symbol? If you can draw it in five seconds, and everyone knows what it is."
Criticism
In order to achieve an abstract goal, architects often plan outside the needs of their clients. The Chicago physician Edith Farnsworth, who commissioned Ludwig Mies van der Rohe in 1945 to design a weekend house in which she could retreat for relaxation, was not impressed by the purism of her Farnsworth House, which cost her a lot of money, and expressed herself to the architect as follows: "I wanted something "meaningful," and all I got was this smooth, superficial sophistry" (in German: )
And it was precisely this mansion that became a place of pilgrimage for architectural tourists. People LeBlanc writes about: "The architectural tourist is a courageous man who easily plans a whole journey to see a certain building; who looks for half a day to find it; who lingers for hours at the threshold, hoping to enter. But his tenacity is worth it, because to fully understand a building, you have to see it for yourself." (in German: )
Jürgen Tietz, who in the Neuen Zürcher Zeitung critically examines the urge for ever new architectural symbols triggered by the so-called "Bilbao effect" of Frank O. Gehry's Guggenheim Museum in the Basque Bilbao, also takes up the fact that you have to see a building yourself. First this fashion wave reached the metropolises before it reached the smaller cities, because the more distinctive a building is, the better it can be marketed. Well-known buildings ensure that individual locations are immediately recognizable: The Eiffel Tower stands for Paris and the Parthenon for Athens.
In the times of globalization architectural icons are becoming trademarks in the competition between metropolises: "At the same time, the growing inflation on the catwalk of architectural images threatens to contribute to general confusion. Did this house stand in Hamburg, Tokyo or Paris? Was it the museum in Bern, Manchester or Seoul? Was it the architect Eisenman, Koolhaas or Piano?" (in German: ) The dilemma of this architecture, which is oriented towards the visual effect, is that it must rely on the quick glance. Tietz calls it "an architectural fast food that is as easy to consume as possible" (in German: Fast Food). At the same time, it is often forgotten that what constitutes the quality of architecture can only be experienced on location: "But the Modernist building set is also constantly generating new images for worldwide marketing in the architectural circus: ecologically ambitious at Foster, elegantly expressive at Gehry, zigzag deconstructed at Libeskind. (in German: )
However, these computer-designed, constructed marketing strategies threaten, according to Tietz, to turn architecture into a cliché that is full of Potemkin villages.
Some examples
An example of this is the Seagram Building in New York, which became the icon of the modern skyscraper and in the following decades the most imitated example of its kind worldwide. The construction of the Sydney Opera House was part of a rethinking of 1950s architecture.
List (selection)
This list can never be complete, but it should give an overview of the diversity of building.
See also
World Architecture Survey
References
Further reading
External links
Postmodernism
Architectural design | Architectural icon | [
"Engineering"
] | 870 | [
"Design",
"Architectural design",
"Architecture"
] |
61,092,905 | https://en.wikipedia.org/wiki/Judy%20Raper | Judy Agnes Raper (born 1954) is an Australian chemical engineer and was previously Deputy Vice-Chancellor for Research and Innovation at the University of Wollongong. She has served as a National Science Foundation Director and led the Atomic Energy Research Establishment. She has been Dean & CEO of TEDI-London, a new engineering higher education provider since its incorporation in June, 2019.
Early life and education
Raper was born in Budapest. She settled in Australia in 1957. She earned her undergraduate and PhD degrees at the University of New South Wales in 1976 and 1980 respectively. She worked on distillation columns. She was a postdoctoral researcher at the University of Cambridge, where she worked at the Atomic Energy Research Establishment.
Research and career
Raper was appointed lecturer at the University of Newcastle in 1982. She joined the University of New South Wales in 1986, where she was Head of Chemical Engineering at the University of New South Wales, where she transformed the undergraduate engineering programme. In 1997 Raper was the first woman to be appointed Dean of the Faculty of Engineering at the University of Sydney. Raper left the University of Sydney to join the University of Missouri as the chair of the Chemical and Biological engineering department in 2003. She spent 2006 on secondment at the National Science Foundation. Her research considers the characterisation of particulates and their impact on pollution control. She has focussed on pharmaceutical and medicinal applications of aerosol powders.
Raper was appointed Deputy Vice-Chancellor of Research and Innovation at the University of Wollongong in July 2008, a position she held until December 2018. She has led bids for federal government capital grants worth $135 million. In 2017 Raper was the second woman to win the Australian and New Zealand Federation of Chemical Engineers Chemeca medal, and used her keynote acceptance speak to talk about the need for diversity in engineering. Raper has spoken about the need for gender equality and increased diversity at the University of Wollongong. She appointed Valerie Linton as the Dean of Engineering and Information Sciences in 2018.
Raper is one of the Founding Deans of the PLuS Alliance, a collaboration between the University of New South Wales, Arizona State University and King's College London.
Awards and honours
Her awards and honours include;
1998 Avon Spirit of Achievement Award for Science
2003 Fellow of the Australian Academy of Technology and Engineering
2003 Honorary Fellow of the Engineers Australia
2012 Australian Financial Review 100 Women of Influence
2017 Australian and New Zealand Federation of Chemical Engineers Chemeca Medal
2018 University of New South Wales Ada Lovelace Medal
2019 Member of the Order of Australia
Fellow of the Royal Society of New South Wales
The University of New South Wales hold a Judy Raper Award for Leadership in her honour.
References
Australian women scientists
Australian women engineers
1954 births
Academic staff of the University of Sydney
University of New South Wales alumni
Academic staff of the University of Wollongong
Members of the Order of Australia
Living people
Australian chemical engineers
Fellows of the Royal Society of New South Wales
Chemical engineering academics
20th-century women engineers
21st-century Australian women engineers
Fellows of the Australian Academy of Technological Sciences and Engineering | Judy Raper | [
"Chemistry"
] | 617 | [
"Chemical engineering academics",
"Chemical engineers"
] |
61,092,979 | https://en.wikipedia.org/wiki/Macaroons%20%28computer%20science%29 | In computer security, macaroons are authorization credentials that support decentralized delegation between principals.
Macaroons are used in a variety of systems, including the Ubuntu Snappy package manager, the HyperDex data store, the Matrix communication protocol, and the Python Package Index.
Claims
A macaroon is composed of series of "caveats", for example:
may upload files to /user/A/ (issued by server)
only to /user/A/album/123 (derived by A)
only GIFs, up to 1MB (derived by B)
until noon today (derived by C)
The macaroon model doesn't specify the language for these caveats; The original paper proposes a model of subjects and rights, but the details are left to individual implementations.
Related technologies
Macaroons are similar to some other technologies.
Compared to JSON Web Token (JWT):
Holder of macaroon can issue a sub-macaroon with smaller power, while JWT is fixed
Macaroon is notably longer than JWT
Macaroon is equivalent to signed JWT, but does not offer equivalent to encrypted JWT
Compared to Certificates
Macaroons are based on a symmetric model, while certificates on asymmetric
Macaroons are computationally cheaper and require simpler cryptographic primitives
Using a macaroon (sent to a server) can disclose some private information held by the macaroon holder, meaning that server must be trusted; Using a certificate means signing a payload using a private key, which is not sent to the server, thus communication with untrusted servers is less risky.
Invalidation
Implementations need to decide whether the entire macaroon tree is invalidated at once from its root, the server secret key; or if intermediate macaroons are to be blacklisted, comparable to time-bound JWT's.
See also
Authorization
HTTP cookie
OAuth
OpenID
Simple public-key infrastructure
References
Computer access control | Macaroons (computer science) | [
"Technology",
"Engineering"
] | 406 | [
"Computer security stubs",
"Computing stubs",
"Cybersecurity engineering",
"Computer access control"
] |
61,094,236 | https://en.wikipedia.org/wiki/Interpolation%20sort | Interpolation sort is a sorting algorithm that is a kind of bucket sort. It uses an interpolation formula to assign data to the bucket. A general interpolation formula is:
Interpolation = INT(((Array[i] - min) / (max - min)) * (ArraySize - 1))
Algorithm
Interpolation sort (or histogram sort).
It is a sorting algorithm that uses the interpolation formula to disperse data divide and conquer. Interpolation sort is also a variant of bucket sort algorithm.
The interpolation sort method uses an array of record bucket lengths corresponding to the original number column. By operating the maintenance length array, the recursive algorithm can be prevented from changing the space complexity to due to memory stacking. The segmentation record of the length array can using secondary function dynamically declare and delete the memory space of the array. The space complexity required to control the recursive program is . Contains a two-dimensional array of dynamically allocated memories and an array of record lengths. However the execution complexity can still be maintained as an efficient sorting method of .
Array of dynamically allocated memory can be implemented by linked list, stack, queue, associative array, tree structure, etc. An array object such as JavaScript is applicable. The difference in data structure is related to the speed of data access and thus the time required for sorting.When the values in the ordered array are uniformly distributed approximately the arithmetic progression, the linear time of interpolation sort ordering is .
Interpolation sort algorithm
Set a bucket length array to record the length of the unsorted bucket. Initialize into the original array length.
[Main Sort] If the bucket length array is cleared and sorted is completed. Execute [Divide function] if it is not cleared.
[Divide function] Execute Divide by pop a bucket length from the end of the bucket length array. Find the maximum and minimum values in the bucket. If the maximum value is equal to the minimum value, the sorting is completed to stop Divide.
Set up a two-dimensional array as all empty buckets. Divide into the bucket according to the interpolation number.
After dividing into the buckets, push the length of the buckets into the array of bucket length. And put the items back into the original array one by one from all the buckets that are not empty.
Return to [Main Sort].
Histogram sort algorithm
The NIST definition: An efficient 3-pass refinement of a bucket sort algorithm.
The first pass counts the number of items for each bucket in an auxiliary array, and then makes a running total so each auxiliary entry is the number of preceding items.
The second pass puts each item in its proper bucket according to the auxiliary entry for the key of that item.
The last pass sorts each bucket.
Practice
Interpolation sort implementation
JavaScript code:
Array.prototype.interpolationSort = function()
{
var divideSize = new Array();
var end = this.length;
divideSize[0] = end;
while (divideSize.length > 0) { divide(this); }
// Repeat function divide to ArrayList
function divide(A) {
var size = divideSize.pop();
var start = end - size;
var min = A[start];
var max = A[start];
for (var i = start + 1; i < end; i++) {
if (A[i] < min) { min = A[i]; }
else { if (A[i] > max) { max = A[i]; } }
}
if (min == max) { end = end - size; }
else {
var p = 0;
var bucket = new Array(size);
for (var i = 0; i < size; i++) { bucket[i] = new Array(); }
for (var i = start; i < end; i++) {
p = Math.floor(((A[i] - min ) / (max - min ) ) * (size - 1 ));
bucket[p].push(A[i]);
}
for (var i = 0; i < size; i++) {
if (bucket[i].length > 0) {
for (var j = 0; j < bucket[i].length; j++) { A[start++] = bucket[i][j]; }
divideSize.push(bucket[i].length);
}
}
}
}
};
Interpolation sort recursive method
Worst-case space complexity :
Array.prototype.interpolationSort= function()
{//-- Edit date:2019/08/31 --//
var start = 0;
var size = this.length;
var min = this[0];
var max = this[0];
for (var i = 1; i < size; i++) {
if (this[i] < min) { min = this[i]; }
else {if (this[i] > max) { max = this[i];} }
}
if (min != max) {
var bucket = new Array(size);
for (var i = 0; i < size; i++) { bucket[i] = new Array(); }
var interpolation = 0;
for (var i = 0; i < size; i++) {
interpolation = Math.floor(((this[i] - min) / (max - min)) * (size - 1));
bucket[interpolation].push(this[i]);
}
for (var i = 0; i < size; i++) {
if (bucket[i].length > 1) { bucket[i].interpolationSort(); } // Recursion
for (var j = 0; j < bucket[i].length; j++) { this[start++] = bucket[i][j]; }
}
}
};
Histogram sort implementation
Array.prototype.histogramSort = function()
{//-- Edit date:2019/11/14 --//
var end = this.length;
var sortedArray = new Array(end);
var interpolation = new Array(end);
var hitCount = new Array(end);
var divideSize = new Array();
divideSize[0] = end;
while (divideSize.length > 0) { distribute(this); }
// Repeat function distribute to Array
function distribute(A) {
var size = divideSize.pop();
var start = end - size;
var min = A[start];
var max = A[start];
for (var i = start + 1; i < end; i++) {
if (A[i] < min) { min = A[i]; }
else { if (A[i] > max) { max = A[i]; } }
}
if (min == max) { end = end - size; }
else {
for (var i = start; i < end; i++) { hitCount[i] = 0; }
for (var i = start; i < end; i++) {
interpolation[i] = start + Math.floor(((A[i] - min ) / (max - min ) ) * (size - 1 ));
hitCount[interpolation[i]]++;
}
for (var i = start; i < end; i++) {
if (hitCount[i] > 0) { divideSize.push(hitCount[i]); }
}
hitCount[end-1] = end - hitCount[end-1];
for (var i = end-1; i > start; i--) {
hitCount[i-1] = hitCount[i] - hitCount[i-1];
}
for (var i = start; i < end; i++) {
sortedArray[hitCount[interpolation[i]]] = A[i];
hitCount[interpolation[i]]++;
}
for (var i = start; i < end; i++) { A[i] = sortedArray[i]; }
}
}
};
Variant
Interpolation tag sort
Interpolation Tag Sort is a variant of Interpolation Sort. Applying the bucket sorting and dividing method, the array data is distributed into a limited number of buckets by mathematical interpolation formula, and the bucket then recursively the original processing program until the sorting is completed.
Interpolation tag sort is a recursive sorting method for interpolation sorting. To avoid stacking overflow caused by recursion, the memory crashes. Instead, use a Boolean data type tag array to operate the recursive function to release the memory. The extra memory space required is close to . Contains a two-dimensional array of dynamically allocated memory and a Boolean data type tag array. Stack, queue, associative array, and tree structure can be implemented as buckets.
As the JavaScript array object is suitable for this sorting method, the difference in data structure is related to the speed of data access and thus the time required for sorting. The linear time Θ(n) is used when the values in the array to be sorted are evenly distributed. The bucket sort algorithm does not limit the sorting to the lower limit of . Interpolation tag sort average performance complexity is .
Interpolation tag sort algorithm
Set a tag array equal to the original array size and initialize to a false value.
[Main Sort] Determines whether all buckets of the original array have been sorted. If the sorting is not completed, the [Divide function] is executed.
[Divide function] Find the maximum and minimum values in the bucket. If the maximum value is equal to the minimum value, the sorting is completed and the division is stopped.
Set up a two-dimensional array as all the empty buckets. Divide into the bucket according to the interpolation number.
After dividing into the bucket, mark the starting position of the bucket as a true value in the tag array. And put the items back into the original array one by one from all the buckets that are not empty.
Return to [Main Sort].
Practice
JavaScript code:
Array.prototype.InterpolaionTagSort = function()
{// Whale Chen agrees to "Wikipedia CC BY-SA 3.0 License". Sign date: 2019-06-21 //
var end = this.length;
if (end > 1) {
var start = 0 ;
var Tag = new Array(end); // Algorithm step-1
for (var i = 0; i < end; i++) { Tag[i] = false; }
Divide(this);
}
while (end > 1) { // Algorithm step-2
while (Tag[--start] == false) { } // Find the next bucket's start
Divide(this);
}
function Divide(A) {
var min = A[start];
var max = A[start];
for (var i = start + 1; i < end; i++) {
if (A[i] < min) { min = A[i]; }
else { if (A[i] > max) { max = A[i]; } } }
if ( min == max) { end = start; } // Algorithm step-3 Start to be the next bucket's end
else {
var interpolation = 0;
var size = end - start;
var Bucket = new Array( size ); // Algorithm step-4
for (var i = 0; i < size; i++) { Bucket[i] = new Array(); }
for (var i = start; i < end; i++) {
interpolation = Math.floor (((A[i] - min) / (max - min)) * (size - 1));
Bucket[interpolation].push(A[i]);
}
for (var i = 0; i < size; i++) {
if (Bucket[i].length > 0) { // Algorithm step-5
Tag[start] = true;
for (var j = 0; j < Bucket[i].length; j++) { A[start++] = Bucket[i][j]; }
}
}
}
} // Algorithm step-6
};
In-place Interpolation Tag Sort
The in-place interpolation tag sort is an in-place algorithm of interpolation sort. In-place Interpolation Tag Sort can achieve sorting by only N times of swapping by maintaining N bit tags; however, the array to be sorted must be a continuous integer sequence and not repeated, or the series is completely evenly distributed to approximate The number of arithmetical progression.
The factor column data must not be repeated. For example, sorting 0~100 can be sorted in one step. The number of exchanges is: , the calculation time complexity is: , and the worst space complexity is . If the characteristics of the series meet the conditional requirements of this sorting method: "The array is a continuous integer or an arithmetical progression that does not repeat", the in-place interpolation tag sort will be an excellent sorting method that is extremely fast and saves memory space.
In-place Interpolation Tag Sort Algorithm
In-place Interpolation Tag Sort sorts non-repeating consecutive integer series, only one Boolean data type tag array with the same length as the original array, the array calculates the interpolation of the data from the beginning, and the interpolation points to a new position of the array. Position, the position that has been swapped is marked as true in the corresponding position of the tag array, and is incremented until the end of the array is sorted.
Algorithm process:
Set an equal number of tag arrays to initialize to false values.
Visit the array when tag[i] is false, calculate the position corresponding to the interpolation=p.
Swap a[i] and a[p], let tag[p] = true.
The tour array is completed and the sorting is completed.
Practice
JavaScript code:
Array.prototype.InPlaceTagSort = function()
{ // Edit Date: 2019-07-02
var n = this.length;
var Tag = new Array(n);
for (i = 0; i < n; i++) { Tag[i] = false; }
var min = this[0];
var max = this[0];
for (i = 1; i < n; i++) { if (this[i] < min) { min = this[i]; }
else { if (this[i] > max) { max = this[i]; } } }
var p = 0;
var temp = 0;
for (i = 0; i < n; i++) {
while (Tag[i] == false) {
p = Math.floor(((this[i] - min) / (max - min)) * (n - 1));
temp = this[i];
this[i] = this[p];
this[p] = temp;
Tag[p] = true;
}
}
};
needSortArray.InPlaceTagSort();
The origin of In-place sorting performed in O(n) time
In "Mathematical Analysis of Algorithms", Donald Knuth remarked "... that research on computational complexity is an interesting way to sharpen our tools for more routine problems we face from day to day."
Knuth further pointed out that, with respect to the sorting problem, time effective in-situ permutation is inherently connected with the problem of finding the cycle leaders, and in-situ permutations could easily be performed in time if we would be allowed to manipulate extra "tag" bits specifying how much of the permutation has been carried out at any time. Without such tag bits, he concludes "it seems reasonable to conjecture that every algorithm will require for in-situ permutation at least steps on the average."
The In-place Interpolation Tag Sort is one of the sorting algorithms that prof. Donald Knuth said: "manipulate extra "tag" bits...finding the cycle leaders, and in-situ permutations could easily be performed in time".
Similar sorting method
Flashsort
Proxmap sort
American flag sort
Bucket sort mixing other sorting methods and recursive algorithm
Bucket sort can be mixed with other sorting methods to complete sorting. If it is sorted by bucket sort and insert sort, also is a fairly efficient sorting method. But when the series appears a large deviation from the value: For example, when the maximum value of the series is greater than N times the next largest value. After the series of columns are processed, the distribution is that all the elements except the maximum value fall into the same bucket. The second sorting method uses insert sort. May cause execution complexity to fall into . This has lost the meaning and high-speed performance of using bucket sort.
Interpolation sort is a way of recursively using bucket sort. After performing recursion, still use bucket sort to disperse the series. This can avoid the above situation. If you want to make the recursive interpolation sort execution complexity fall into , it is necessary to present a factorial amplification in the entire series. In fact, there is very little chance that a series of special distributions will occur.
References
External links
interpolationSort.html
histogramSort.html
The FlashSort Algorithm
Mathematical Analysis of Algorithms
http://www.drdobbs.com/database/the-flashsort1-algorithm/184410496
桶排序遞迴方式演算法 Bucket sort Recursive method. Whale Chen 2012/09/16
插值標簽排序演算法 Interpolation Tag Sort Algorithm. Whale Chen 2013/03/24
interpolation sort (Pascal version available)
w3schools JavaScript Array Sort testing platform
Sorting algorithms
Stable sorts | Interpolation sort | [
"Mathematics"
] | 3,886 | [
"Order theory",
"Sorting algorithms"
] |
61,094,758 | https://en.wikipedia.org/wiki/Natural%20element%20method | The natural element method (NEM) is a meshless method to solve partial differential equation, where the elements do not have a predefined shape as in the finite element method, but depend on the geometry.
A Voronoi diagram partitioning the space is used to create each of these elements.
Natural neighbor interpolation functions are then used to model the unknown function within each element.
Applications
When the simulation is dynamic, this method prevents the elements to be ill-formed, having the possibility to easily redefine them at each time step depending on the geometry.
References
Numerical differential equations
Numerical analysis
Computational fluid dynamics
Computational mathematics
Simulation | Natural element method | [
"Physics",
"Chemistry",
"Mathematics"
] | 130 | [
"Computational fluid dynamics",
"Applied mathematics",
"Computational mathematics",
"Computational physics",
"Mathematical relations",
"Numerical analysis",
"Approximations",
"Fluid dynamics"
] |
61,094,890 | https://en.wikipedia.org/wiki/Scuba%20cylinder%20valve | A scuba cylinder valve or pillar valve is a high pressure manually operated screw-down shut off valve fitted to the neck of a scuba cylinder to control breathing gas flow to and from the pressure vessel and to provide a connection with the scuba regulator or filling whip. Cylinder valves are usually machined from brass and finished with a protective and decorative layer of chrome plating. A metal or plastic dip tube or valve snorkel screwed into the bottom of the valve extends into the cylinder to reduce the risk of liquid or particulate contaminants in the cylinder getting into the gas passages when the cylinder is inverted, and blocking or jamming the regulator.
Cylinder valves are classified by four basic aspects: the thread specification for attachment to the cylinder, the connection to the regulator, pressure rating, and some functional distinguishing features. Standards relating to the specifications and manufacture of cylinder valves include ISO 10297 and CGA V-9 Standard for Gas Cylinder Valves.
Structure of the valve
The valve body is usually machined from a solid brass casting or forging, which is screwed into the cylinder neck thread, and sealed by o-ring or thread tape. The outlet is machined to fit one of the standard scuba regulator connection systems, and a gas passage is provided from the interior of the cylinder to the regulator connection. Control of gas flow through the gas passage is by opening and closing a valve orifice machined into the valve body, by turning the valve knob to drive the valve spindle which moves the valve seat towards or away from the orifice. The spindle engages with the valve seat by a flat and slot or a square socket on the inner end of the spindle, which passes through the spindle seal in the valve bonnet. Rotation of the seat drives it along its axis on a screw thread concentric with the orifice. The spindle is usually sealed by an O-ring where it passes through the bonnet, and axial loads on the spindle are usually carried by a teflon or similar low friction coefficient washer. Other arrangements have been used, but the one described is very common and is known as a balanced valve because the pressure of the gas in the cylinder is exerted on both sides of the valve seat when it is not sealed, because the gas can leak past the threads of the seat. Historically, two other spindle arrangements were also used, the unbalanced valve where the periphery of the seat is sealed, and the glandless valve, where the valve seat does not rotate, but is sealed into the valve body behind a diaphragm. The valve outlet is connected to a regulator for diving, or a filling whip for charging. The valve must be open for these operations, and closed to keep the gas inside the cylinder for storage.
Cylinder neck threads
The neck of the cylinder is the part of the end which is shaped as a narrow concentric cylinder, and internally threaded to fit a cylinder valve. Cylinder threads may be in two basic configurations: Taper thread and parallel thread. The valve thread specification must exactly match the neck thread specification of the cylinder. Improperly matched neck threads can fail under pressure which can have fatal consequences. Parallel threads are more tolerant of repeated removal and refitting of the valve for inspection and testing.
There are several standards for neck threads, these include:
Taper thread (17E), with a 12% taper right hand thread, standard Whitworth 55° form with a pitch of 14 threads per inch (5.5 threads per cm) and pitch diameter at the top thread of the cylinder of . These connections are sealed using thread tape and torqued to between on steel cylinders, and between on aluminium cylinders.
Parallel threads are made to several standards:
M25x2 ISO parallel thread, which is sealed by an O-ring and torqued to on steel, and on aluminium cylinders;
M18x1.5 parallel thread, which is sealed by an O-ring, and torqued to on steel cylinders, and on aluminium cylinders;
3/4"x14 BSP parallel thread, which has a 55° Whitworth thread form, a pitch diameter of and a pitch of 14 threads per inch (1.814 mm);
3/4"x14 NGS (NPSM) parallel thread, sealed by an O-ring, torqued to on aluminium cylinders, which has a 60° thread form, a pitch diameter of , and a pitch of 14 threads per inch (1.814 mm);
3/4"x16 UNF, sealed by an O-ring, torqued to on aluminium cylinders.
7/8"x14 UNF, sealed by an O-ring.
The 3/4"NGS and 3/4"BSP are very similar, having the same pitch and a pitch diameter that only differs by about , but they are not compatible, as the thread forms are different.
All parallel thread valves are sealed using an O-ring at the top of the neck thread which seals in a chamfer or step in the cylinder neck and against the flange of the valve.
Connection to the regulator
A rubber O-ring forms a seal between the metal of the cylinder valve and the metal of the diving regulator. Fluoroelastomer (e.g. viton) O-rings may be used with cylinders filled with oxygen-rich breathing gas mixtures to reduce the risk of fire. There are two basic types of cylinder valve to regulator connection in general use for scuba cylinders. They are both very widely used for cylinders containing air and in many countries also for other breathing gases for diving:
Yoke connectors
The yoke connector, also known as an A-clamp or international connector, is a component of the regulator that fits around the valve body at the outlet and presses the outlet O-ring of the valve against the inlet seat of the regulator. The connection is officially described as connection CGA 850 yoke. The yoke clamping screw is screwed down snug by hand to ensure metal to metal contact between the valve and regulator to sufficiently constrain the O-ring against extrusion. Overtightening can make the yoke impossible to remove later without tools. The seal is created by clamping the O-ring mounted in a groove on the face of the valve between the surfaces of the regulator and valve. When the valve is opened, cylinder pressure expands the O-ring against the outer surface of the O-ring groove in the valve and the face of the regulator inlet. This type of connection is simple, cheap and very widely used worldwide. Several O-ring sizes are in use, and both overall and section diameters may vary, but the correct size for the valve is necessary for a reliable seal and so that the O-ring does not easily fall out during handling and storage. It has a maximum pressure rating of 240 bar, and is not well protected against overpressurisation. Insufficient clamping force may allow the pressure to slightly stretch the yoke structure, opening a gap between the sealing faces of the valve and the regulator sufficient to extrude the O-ring through the gap, resulting in a potentially catastrophic leak. A similar effect can occur if the first stage is bumped against the environment, flexing the yoke enough to open a gap. When underwater this is most likely in an overhead environment where the diver cannot make an immediate emergency ascent. The risk of this cause for O-ring extrusion is roughly proportional to the pressure in the cylinder, and is less for a more rigid yoke structure. Older regulators may have a yoke rated at 200 bar, and these may not fit over more recent 240 bar valves.
DIN connectors
In the DIN screw thread connectors, the regulator screws into the cylinder valve, trapping the O-ring securely between the sealing face of the valve and the O-ring groove in the regulator. These are more reliable than A-clamps because the O-ring is well protected and the assembly is considerably more rigid, and has a lower profile, making O-ring extrusion under impact less likely, but operators in many countries do not widely use DIN filling connectors on compressors, or cylinder valves which have DIN fittings, so a diver traveling abroad with a DIN system may need to take an adaptor, either for connecting the DIN regulator to a rented cylinder, or for connecting an A-clamp filler hose to a DIN cylinder valve. The DIN connection is slightly more complex to manufacture, but if the seal is good when the valve is opened it is likely to remain good throughout a dive, even if banged against a solid overhead, and is consequently preferred by technical divers even where the yoke fitting is more generally popular. DIN connections are available in two specifications; for working pressures up to 232 bar, and for 300 bar. The original design 200 bar regulator fitting with five threads will not seal in a 300 bar valve, preventing potential overload, particularly of the high pressure hose and submersible pressure gauge, but the DIN 300 bar regulator inlet fitting with seven threads available on almost all recent regulators is compatible with 200 and 232 bar valves as well as the 300 bar valves. The thread form is G5/8" x 14 tpi. The O-ring is carried in a groove on the regulator. Two sizes of O-ring are in common use.
Adaptors
Adaptors are available to allow connection of DIN regulators to yoke cylinder valves (A-clamp or yoke adaptor), and to connect yoke regulators to DIN cylinder valves. There are two types of adaptors for DIN valves: plug adaptors and block adaptors. Plug adaptors are screwed into a 5-thread DIN valve socket, are rated for 232/240 bar, and can only be used with valves which are designed to accept them. These can be recognised by a dimple recess opposite to the outlet opening, used to locate the screw of an A-clamp. Block adaptors are generally rated for 200 bar, and can be used with almost any 200 bar 5-thread DIN valve. A-clamp or yoke adaptors comprise a yoke clamp with a DIN socket in line. They are slightly more vulnerable to O-ring extrusion than integral yoke clamps, due to greater leverage on the first stage regulator.
Conversion kits
Several manufacturers market an otherwise identical first stage varying only in the choice of cylinder valve connection. In these cases it may be possible to buy original components to convert yoke to DIN and vice versa. The complexity of the conversion may vary, and parts are not usually interchangeable between manufacturers. The conversion of Apeks regulators is particularly simple and only requires an Allen key and a ring spanner.
Valves for gases other than air
There are also cylinder valves for scuba cylinders containing gases other than air:
The European Norm EN 144-3:2003 introduced a new type of valve, similar to existing 232 bar or 300 bar DIN valves, but with a metric M26×2 thread connecting the cylinder to the regulator. These are intended to be used for breathing gas with oxygen content above that normally found in natural atmospheric air (i.e. 22–100%). From August 2008, these were required in the European Union for all diving equipment used with nitrox or pure oxygen. The idea behind this new standard is to prevent a rich mixture being filled to a cylinder that is not oxygen clean. However even with use of the new system there still remains nothing except human procedural care to ensure that a cylinder with a new valve remains oxygen-clean - which is exactly how the previous system worked. The enriched oxygen valve may alert the user to a non-air breathing gas, but will give no indication of the actual composition of the contents. Filling adaptors are available as a stock item to allow filling of cylinders fitted with these valves from a standard G5/8" DIN filling connector.
An M 24x2 male thread cylinder valve was supplied with some Dräger semi-closed circuit recreational rebreathers (Dräger Ray) for use with nitrox mixtures. The regulator supplied with the rebreather had a compatible connection.
Internal and other replaceable components of valves are often interchangeable amongst other valves from the same manufacturer for similar service.
Handwheel
The handwheel or valve knob is a knurled or ridged rubber, plastic or metal fitting attached to the valve spindle, used to rotate the spindle to open and close the valve. Hard rubber or tough plastic are the usual materials on recent models, usually incorporating moulded grips and a metal insert to engage the square or flatted part of the spindle, to which they are usually attached by a slotted nut.
Dip tube
The dip tube, anti-debris tube, or valve snorkel is a short tube screwed into the hole in the bottom of the valve body, which projects into the cylinder internal space. Its function is to prevent any loose debris inside the cylinder from getting into the outlet passages if the cylinder is inverted in use, as such material may clog or jam the regulator. Originally mostly made from brass tube, they are also often made from plastic, but brass is still preferred for high oxygen fraction gas mixes, as it is a lower fire hazard. Some dip tubes have a filter attached to the lower end, often made from sintered brass, but most have a plain opening.
Pressure rating
Yoke valves are rated between 200 and 240 bar, and there does not appear to be any mechanical design detail preventing connection between any yoke fittings, though some older yoke clamps will not fit over the popular 232/240 bar combination DIN/yoke cylinder valve as the yoke is too narrow.
DIN valves are produced in 200 bar and 300 bar pressure ratings. The number of threads and the detail configuration of the connections is designed to prevent incompatible combinations of filler attachment or regulator attachment with the cylinder valve.
232 bar DIN (5-thread, G5/8) Outlet/Connector #13 to DIN 477 part 1 - (technically they are specified for cylinders with 300 bar test pressure)
300 bar DIN (7-thread, G5/8) Outlet/Connector #56 to DIN 477 part 5 - these are similar to 5-thread DIN fitting but are rated to 300 bar working pressures. (technically they are specified for cylinders with 450 bar test pressure). The 300 bar pressures are common in European diving and in US cave diving.
Other distinguishing features
Plain valves
The most commonly used cylinder valve type is the single outlet plain valve, sometimes known as a "K-valve", which allows connection of a single regulator, and has no reserve function. It simply opens to allow gas flow, or closes to shut it off. Several configurations are used, with options of DIN or A-clamp connection, and vertical or transverse spindle arrangements.
Reserve valves
Until the 1970s, when submersible pressure gauges on regulators came into common use, diving cylinders often used a mechanical reserve mechanism to indicate to the diver that the cylinder was nearly empty. The gas supply was automatically cut-off by a spring loaded valve when the gas pressure reached the reserve pressure. To release the reserve, the diver pulled down on a rod that ran along the side of the cylinder and which activated a lever to open a bypass valve. The diver would then finish the dive before the reserve was consumed. The reserve could be adjusted by spring stiffness, typically for a single cylinder, but for twin sets and triple sets . On occasion, divers would inadvertently trigger the mechanism while donning gear or performing a movement underwater and, not realizing that the reserve had already been accessed, could find themselves out of air at depth with no warning whatsoever. These valves became known as "J-valves" from being item "J" in one of the first scuba equipment manufacturer catalogs. The standard non-reserve yoke valve at the time was item "K", and is often still referred to as a "K-valve". J-valves are still occasionally used by professional divers in zero visibility, where the submersible pressure gauge (SPG) can not be read. While the recreational diving industry has largely discontinued support and sales of the J-valve, the US Department of Defense, the US Navy, NOAA (the National Oceanographic and Atmospheric Administration) and OSHA (the national Occupational Health and Safety Administration) all still allow or recommend the use of J-valves as an alternative to a bailout cylinder or as an alternative to a submersible pressure gauge. They are generally not available through recreational dive shops, but are still available from some manufacturers. They can be significantly more expensive than K-valves from the same manufacturer.
Less common in the 1950s to 1970s was an "R-valve" which was equipped with a restriction that caused breathing to become difficult as the cylinder neared exhaustion, but that would allow less restricted breathing if the diver began to ascend and the ambient water pressure lessened, providing a larger pressure differential over the orifice. It was never particularly popular because if it was necessary for the diver to descend during exit from a cave or wreck, breathing would become progressively more difficult as the diver went deeper, eventually becoming impossible until the diver could ascend to a low enough ambient pressure.
The reserve valves manufactured by Dräger were similar in function to the spring loaded J-valve, but the reserve valve completely bypassed the main valve when opened. Poseidon at one stage marketed a manifold for twin cylinders which featured a pair of plain valves in the cylinders, with a reserve valve mounted on the central outlet block of the manifold. This mechanism retained reserve pressure in both cylinders, where the usual arrangement with manifolded cylinders was to have the reserve gas retained in only one cylinder, therefore necessitating the use of different springs to maintain a roughly constant proportion of the total gas supply.
When filling the cylinder the J-valve will obstruct the inward flow of gas unless both the main and reserve valves are opened.
Dual outlet valves
Y and H cylinder valves have two outlets, each with its own valve, allowing two regulators to be connected to the cylinder. If one regulator "freeflows", which is a common failure mode, or ices up, which can happen in water below about 5 °C, its valve can be closed and the cylinder breathed from the regulator connected to the other valve. The difference between an H-valve and a Y-valve is that the Y-valve body splits into two posts roughly 90° to each other and 45° from the vertical axis, looking like a Y, while an H-valve is usually assembled from a valve designed as part of a manifold system with an additional valve post connected to the manifold socket, with the valve posts parallel and vertical, which looks a bit like an H. Y-valves are also known as "slingshot valves" due to their appearance. Another style of dual outlet valve has the openings at 90° to each other and to the cylinder centreline. These are used on rebreather cylinders so that a bailout regulator can be fitted as well as the rebreather supply regulator.
Handed valves
Some cylinder valve models have axial spindles - in line with the cylinder axis, and are not handed. Standard side-spindle valves have the valve knob on the diver's right side when back-mounted. Side-spindle valves used with manifolds must be a handed pair - one with the knob to the right and the other with the knob to the left, but in all cases the valve is opened by turning the knob anticlockwise, and closed by turning it clockwise. This is the convention with almost all valves for all purposes. Left and right hand side-spindle valves are used by sidemount divers. These may be blanked off manifold valves or specially made for the purpose.
Modular valves
Valves which can be assembled as single or dual outlet valves, or as the paired valves of a manifold system are known as modular valves. They are generally available as left and right hand valves, with a second unvalved outlet into which a blanking plug, a second valve, or the end of a plain or isolation manifold can be screwed. The secondary outlet for one side may have left hand thread, usually indicated by a groove around the hexagon of the nut, as manifolds usually have some centre distance adjustment by rotating the manifold on its axis, which will screw it into or out of both valves at the same time. This makes it necessary to have matching thread on the plugs or secondary valves.
A more complex modular valve system was introduced by Poseidon, where a wide variety of configurations could be assembled out of a set of standardised parts.
Bursting disk
Some national standards require that the cylinder valve includes a bursting disk, a pressure relief device that will release the gas before the cylinder fails in the event of overpressurization. If a bursting disk ruptures during a dive the entire contents of the cylinder will be lost in a very short time. The risk of this happening to a correctly rated disc, in good condition, on a correctly filled cylinder is very low. Burst disk over-pressure protection is specified in the CGA Standard S1.1. Standard for Pressure Relief Devices. Bursting disc rupture pressure is generally rated at 85% to 100% of test pressure.
Accessories
Additional components for convenience, protection or other functions, not directly required for the function as a valve.
Manifolds
A cylinder manifold is a tube which connects two cylinders together so that the contents of both can be supplied to one or more regulators.
There are three commonly used configurations of manifold. The oldest type is a tube with a connector on each end which is attached to the cylinder valve outlet, and an outlet connection in the middle, to which the regulator is attached. A variation on this pattern includes a reserve valve at the outlet connector. The cylinders are isolated from the manifold when closed, and the manifold can be attached or disconnected while the cylinders are pressurised.
More recently, manifolds have become available which connect the cylinders on the cylinder side of the valve, leaving the outlet connection of the cylinder valve available for connection of a regulator. This means that the connection cannot be made or broken while the cylinders are pressurised, as there is no valve to isolate the manifold from the interior of the cylinder. This apparent inconvenience allows a regulator to be connected to each cylinder, and isolated from the internal pressure independently, which allows a malfunctioning regulator on one cylinder to be isolated while still allowing the regulator on the other cylinder access to all the gas in both cylinders. These manifolds may be plain or may include an isolation valve in the manifold, which allows the contents of the cylinders to be isolated from each other. This allows the contents of one cylinder to be isolated and secured for the diver if a leak at the cylinder neck thread, manifold connection, or burst disk on the other cylinder causes its contents to be lost. A relatively uncommon manifold system is a connection which screws directly into the neck threads of both cylinders, and has a single valve to release gas to a connector for a regulator. These manifolds can include a reserve valve, either in the main valve or at one cylinder. This system is mainly of historical interest.
Valve cage
Also known as a manifold cage or regulator cage, this is a structure which can be clamped to the neck of the cylinder or manifolded cylinders to protect the valves and regulator first stages from impact and abrasion damage while in use and from rolling the valve closed by friction of the handwheel against an overhead. A valve cage is often made of stainless steel, and some designs can snag on obstructions and lines.
Dust caps
Plastic covers are held over the opening by friction, or screwed into a DIN valve socket to keep dust and spray from entering the opening. They are generally not 100% reliable, and it is considered prudent to open the valve slightly to blow out any contamination before making a connection to filler hose or regulator.
Extension handle
A valve knob extension (slob knob) is a fairly long flexible extension to a valve spindle allowing the diver to open and close the valve if it is in a position where the diver cannot normally reach it.
Standards
Standards relating to the specifications and manufacture of cylinder valves include ISO 10297 and CGA V-9 Standard for Gas Cylinder Valves, both of which specify design, testing and marking of cylinder valves to be fitted as a closure to refillable transportable gas cylinders. The 8th edition of CGA V-9 brings it into alignment with ISO 10297.
References
Underwater breathing apparatus components
Pressure vessel components
Valves | Scuba cylinder valve | [
"Physics",
"Chemistry"
] | 5,010 | [
"Physical systems",
"Valves",
"Hydraulics",
"Piping",
"Pressure vessels",
"Pressure vessel components"
] |
61,095,265 | https://en.wikipedia.org/wiki/Methane%20reservoir | Methane reservoirs on Earth are mainly found in
Oil and gas reservoirs as natural gas
Coalbeds
the seabed and the Arctic and other permafrost regions as methane clathrate
the atmosphere
decaying organic material
with the exact distribution so far determined by the methane cycle/carbon cycle.
Methane as the main ingredient of natural gas and as an extractable fossil fuel-energy resource has limited if significant reserves. Russia, Iran, and Qatar are topping the list with together , nearly half the world's proven reserves. Methane from gas fields is an important factor in the world energy production and consumption. Methane clathrate is a potential future energy source, if it doesn't escape to the atmosphere before extraction because of global warming. In the atmosphere, it is not only unusable, but also a potent greenhouse gas, further accelerating the current climate change. But even conventional reservoirs are leaking methane (together with other gases like carbon dioxide) especially downstream the processing line.
References
See also
Natural gas storage
Natural-gas condensate
Natural gas
Methane | Methane reservoir | [
"Chemistry"
] | 211 | [
"Greenhouse gases",
"Methane"
] |
61,095,988 | https://en.wikipedia.org/wiki/Arthrophaga%20myriapodina | Arthrophaga myriapodina is a fungus in the Entomophthorales that parasitizes the millipedes Apheloria virginiensis corrugata, Boraria infesta, and Nannaria sp. Infected millipedes typically climb to an elevated spot before death.
Taxonomic history
Arthrophaga myriapodina was first collected by Roland Thaxter from North Carolina in 1886 on Boraria infesta, but he did not formally describe or name it. In 1916, A. T. Speare sent Thaxter additional specimens labelled as Entomophthora myriapodina, but the name was never validly published. Kathie T. Hodge, Ann E. Hajek, and Andrii Gryanskyi showed that A. myriapodina is distinct from related taxa including Entomophthora and formally named it as the type of a new genus.
Morphology
Arthrophaga myriapodina forms distinct white to light brown pustules that emerge between the segments of a millipede. Its primary conidia are pear-shaped and contain 8–18 nuclei, which are forcibly discharged. Notably, no resting spore stage has been observed.
Ecology
Arthrophaga myriapodina is found in eastern North America from May to October, usually 12 to 24 hours after rain.
References
Entomophthorales
Fungus species | Arthrophaga myriapodina | [
"Biology"
] | 296 | [
"Fungi",
"Fungus species"
] |
61,096,673 | https://en.wikipedia.org/wiki/Ecocrop | Ecocrop was a database used to determine the suitability of a crop for a specified environment. Developed by the Food and Agriculture Organization of the United Nations (FAO) it provided information predicting crop viability in different locations and climatic conditions. It also served as a catalog of plants and plant growth characteristics.
History
Ecocrop first emerged in 1991 after planning and initial expert consultancies were completed concerning the development of a database. This system was developed by the Land and Water Development Division of FAO (AGLL) and was launched in 1992. The goal was to create a tool that can identify plant species for given environments and uses, and as an information system contributing to a Land Use Planning concept. In 1994, the Ecocrop database already permitted the identification of more than 1,700 crops and 12-20 environment requirements covering all of the agro-ecological settings of the world. Succeeding iterations of the database from 1998 to 1999 mainly involved improvements to the user interface. By 2000, the database included 2,000 species and 10 additional descriptors. This number was later expanded with the addition of 300 crop species.
The Ecocrop model
The Ecocrop model determines a crop's suitability to a location by evaluating different variables. Specifically, the plant descriptors include category, life form, growth habit, and life span while environmental descriptors include temperature, precipitation, light intensity, Köppen climate classification, photoperiodism, latitude, altitude, and other soil characteristics. The crop database is particularly useful if there is no alternative but to use environmental ranges. Once these inputs are determined, the system produces a suitability index as a percentage. The suitability index score is generated from 0 to 1 with the former indicating totally unsuitable while the latter indicates optimal or excellent suitability. The output also include separated suitability values for temperature and precipitation.
As a prediction model, the Ecocrop algorithm yields data that are more generic than those produced by other models such as DOMAIN and BIOCLIM. The information is generic with respect to the nature of the requirements and is attributed to the lack of information concerning specific crops. Another limitation is that the results depend solely on bioclimatic factors and discounts other variables such as soil requirements, pests, and diseases.
Ecocrop evaluates whether climatic conditions are adequate within a growing season for temperature and precipitation every month. It involves the calculation of climatic suitability based on rainfall and temperature marginal and optimal ranges.
Other uses
Aside from serving as a plant identifier, Ecocrop is also used for other purposes. For instance, it can assess the influence of future climate change on crop suitability. It can also be used to project crop yields using the database's information on optimal and absolute crop growing conditions (minimum temperature, maximum temperature, precipitation values, values that define temperature and precipitation extremes).
References
External links
Crop protection
Biodiversity databases
Online botany databases
Plant taxonomy
Food and Drug Administration | Ecocrop | [
"Biology",
"Environmental_science"
] | 599 | [
"Plants",
"Plant taxonomy",
"Environmental science databases",
"Biodiversity",
"Biodiversity databases"
] |
61,098,760 | https://en.wikipedia.org/wiki/100%20Beste%20Plakate | The association 100 Beste Plakate () e.V. is an interest group for graphics, design and the graphic arts in Germany, Austria and Switzerland. The association was founded with the aim of promoting, awarding and strengthening the public awareness of the high design quality of the poster medium.
History
The 100 Beste Plakate (100 Best Posters) association emerged from the competition Die besten Plakate des Jahres, which was founded in 1966. In 2001, the newly established association took over the organization and realignment of the contest. In the spirit of the European ideal, the contest was expanded to all German-language posters, thus integrating artists from Austria and Switzerland.
Professional associations cooperating with the association are DesignAustria, Alliance Graphique Internationale, the International Council of Graphic Design Associations, the BDG Berufsverband der Deutschen Kommunikationsdesigner e.V. and the AGD. Founding members included Klaus Staeck, Helmut Brade and Volker Pfüller.
Contest
The association organizes a contest annually for the DACH countries. Poster designers, artists, students and printers are invited to submit the best works of the past year. It is also possible for poster clients to nominate them. An annually changing jury of graphic designers selects the 100 best from the submitted posters, which are subsequently awarded and exhibited.
The book 100 Beste Plakate / 100 Best Posters is published to accompany the competition every year.
Exhibitions
The award-winning posters are presented to the public in Berlin (Kulturforum am Potsdamer Platz), Essen, Nuremberg, Lucerne, Zürich and the MAK – Museum of Applied Arts, Vienna as well as other changing locations in multi-week exhibitions. The posters are included in the collections of the Deutsches Plakat Museum (Folkwang Museum) Essen and the MAK.
Presidents
2001 to 2007: Niklaus Troxler
2007 to 2010: Henning Wagenbreth
2010 to 2014: Stephan Bundi
2014 to 2018: Götz Gramlich
since 2018: Fons Matthias Hickmann
Bibliography
100 Beste Plakate e.V. (ed.): 100 beste Plakate 18 – Deutschland Österreich Schweiz. Verlag Kettler, 2018, .
Josef Müller-Brockmann: Geschichte des Plakates. Phaidon Press, 2004, .
Jens Müller (ed.): Best German Posters Optik Books, 2016, .
Fons Hickmann, Sven Lindhorst-Emme (eds.): Anschlag Berlin – Zeitgeistmedium Plakat. Verlag Seltmann+Söhne 2015, .
References
External links
Website and archives of 100 Beste Plakate e.V.
ARTE Journal: Das Plakat, die unterschätzte Kunstform (Video)
Page-Online: 100 Beste Plakate 2016: Die Gewinner sind da
Der Standard: MAK zeigt 100 beste Plakate des Jahres 2017
Tagesspiegel: Ausstellung im Kulturforum: Die hundert besten Plakate
Form: 100 beste Plakate 2017
Art and design organizations
Arts organisations based in Germany | 100 Beste Plakate | [
"Engineering"
] | 669 | [
"Design",
"Art and design organizations"
] |
61,098,866 | https://en.wikipedia.org/wiki/Circular%20measure | A circular measure was used in comparing circular cross-sections, e.g., of wires, etc. A circular unit of the ares is the area of the circle whose diameter is one linear unit.
For example, 1 circular mil is equivalent to 0.7854 square mil in area, 1 circular millimeter = 1550 circular mils = 0.7854 square millimeter. Here
References
Units of measurement | Circular measure | [
"Mathematics"
] | 84 | [
"Quantity",
"Units of measurement"
] |
61,099,017 | https://en.wikipedia.org/wiki/Gestalt%20pattern%20matching | Gestalt pattern matching, also Ratcliff/Obershelp pattern recognition, is a string-matching algorithm for determining the similarity of two strings. It was developed in 1983 by John W. Ratcliff and John A. Obershelp and published in the Dr. Dobb's Journal in July 1988.
Algorithm
The similarity of two strings and is determined by this formula: twice the number of matching characters divided by the total number of characters of both strings. The matching characters are defined as some longest common substring plus recursively the number of matching characters in the non-matching regions on both sides of the longest common substring:
where the similarity metric can take a value between zero and one:
The value of 1 stands for the complete match of the two strings, whereas the value of 0 means there is no match and not even one common letter.
Sample
The longest common substring is WIKIM (light grey) with 5 characters. There is no further substring on the left. The non-matching substrings on the right side are EDIA and ANIA. They again have a longest common substring IA (dark gray) with length 2.
The similarity metric is determined by:
Properties
The Ratcliff/Obershelp matching characters can be substantially different from each longest common subsequence of the given strings. For example and have as their only longest common substring, and no common characters right of its occurrence, and likewise left, leading to . However, the longest common subsequence of and is , with a total length of .
Complexity
The execution time of the algorithm is in a worst case and in an average case. By changing the computing method, the execution time can be improved significantly.
Commutative property
The Python library implementation of the gestalt pattern matching algorithm is not commutative:
Sample
For the two strings
and
the metric result for
is with the substrings GESTALT P, A, T, E and for
the metric is with the substrings GESTALT P, R, A, C, I.
Applications
The Python difflib library, which was introduced in version 2.1, implements a similar algorithm that predates the Ratcliff-Obershelp algorithm. Due to the unfavourable runtime behaviour of this similarity metric, three methods have been implemented. Two of them return an upper bound in a faster execution time. The fastest variant only compares the length of the two substrings:
,
The second upper bound calculates twice the sum of all used characters which occur in divided by the length of both strings but the sequence is ignored.
# Dqr Implementation in Python
import collections
def quick_ratio(s1: str, s2: str) -> float:
"""Return an upper bound on ratio() relatively quickly."""
length = len(s1) + len(s2)
if not length:
return 1.0
intersect = (collections.Counter(s1) & collections.Counter(s2))
matches = sum(intersect.values())
return 2.0 * matches / length
Trivially the following applies:
and
.
References
Further reading
See also
Pattern matching
Search algorithms
Information theory
Quantitative linguistics
Recursion
String metrics
Articles with example Python (programming language) code | Gestalt pattern matching | [
"Mathematics",
"Technology",
"Engineering"
] | 686 | [
"Telecommunications engineering",
"Recursion",
"Applied mathematics",
"Mathematical logic",
"Computational linguistics",
"Computer science",
"Information theory",
"Natural language and computing"
] |
61,099,702 | https://en.wikipedia.org/wiki/Libervia | Libervia (formerly Salut à Toi or SàT) is a multifunctional communications application and decentralized social network published under the AGPL-3.0-or-later license.
Initially made for instant messaging and chat, Libervia developed additional functionality that can be used for microblogging, blogging, filesharing, audio and video streaming, and gaming. It has Atom feeds, and both WYSIWYM and WYSIWYG editors.
It uses XMPP. It also implemented ActivityPub in beta in late 2022, with a gateway that allows the two protocols to intercommunicate, aiming to have it in alpha in early 2023.
Architecture
Libervia uses a client-server architecture. The client consists of a backend daemon (which can be installed locally or on a server) and one of several frontends. Frontends include:
jp, a command-line interface
Cagou, a frontend for desktops and mobile phones
Libervia-web (formerly Libervia), a web interface
Primitivus, a text-based user interface
Third-party frontends include:
Wix, WxWidgets-based desktop GUI (now deprecated)
Bellaciao, Qt-based graphical user interface (development on hold)
Sententia, an Emacs frontend (development is currently stalled)
References
External links
Official website
Free XMPP clients
Microblogging software
Free software programmed in Python
2009 software
Linux software
Android (operating system) software
Cross-platform free software
Software that federates via ActivityPub
Streaming software
Atom (web standard)
Web syndication | Libervia | [
"Technology"
] | 346 | [
"Mobile software stubs",
"Mobile technology stubs"
] |
61,100,576 | https://en.wikipedia.org/wiki/Bess%20Ward | Bess Ward is an American oceanographer, biogeochemist, microbiologist, and William J. Sinclair Professor of Geosciences at Princeton University.
Ward studies include marine and global nitrogen cycles, and how marine organisms such as phytoplankton and bacteria influence the nitrogen cycle. Ward was the first woman awarded the G. Evelyn Hutchinson Award from the Association for the Sciences of Limnology and Oceanography (ASLO) for her pioneering work on applying molecular methods for nitrogen and methane conversions as well as scaling up organismal biogeochemical rates to whole ecosystem rates.
Education and early career
Ward received her Bachelor of Sciences degree in zoology from the Michigan State University in 1976. Ward went on to obtain a Master's degree in biological oceanography from the University of Washington in 1979, followed by her PhD at the same institution in 1982. Ward's early work focused on quantifying the rates of nitrogen transformation performed by bacteria and phytoplankton, and was the editor for a special edition of Marine Chemistry on "Aquatic Nitrogen Cycles" in 1985.
After her PhD, Ward worked as a research biologist and oceanographer at the Scripps Institution of Oceanography in San Diego, California, where she also served as the chairperson of the Food Chain Research Group.
Career
Ward became a professor of Marine Sciences at the University of California, Santa Cruz in 1989. From 1995–1998, Ward was the Chair of the Ocean Sciences Department at University of California, Santa Cruz before becoming a professor in the Department of Geosciences at Princeton University in 1998. In 2006, Ward became the Chair of the Department of Geosciences at Princeton and has held the position ever since. Ward has held numerous visiting scientist and trustee positions throughout her career at institutions such as the Bermuda Institute of Ocean Sciences, Plymouth Marine Laboratory, and the Max Planck Institute für Limnologie. As of 2018, Ward had advised 21 graduate students and 20 postdoctoral scholars. Broadly, Ward and her lab members research how bacteria and phytoplankton transform and use nitrogen in marine and coastal ecosystems using various molecular and isotopic techniques. Ward spends time on research cruises and expeditions, conducting research (and sometimes teaching remotely) while on the ocean for days to weeks at a time.
Nitrogen cycling
Areas in the ocean that are low in oxygen, called oxygen deficient zones (ODZs), are important areas for nitrogen cycling yet only make up about 0.1-0.2% of the total volume of the world ocean. Over one quarter of all nitrogen in the oceans is lost to gaseous nitrogen forms (e.g. N2, N2O) in the ODZs through various nitrogen transformation pathways including denitrification and anammox, however, the rates of nitrogen transformation and type of transformation that is taking place in ODZs remains unclear and subject of much of Ward's research. Ward and her lab developed an isotopic tracer method to measure the rate of N2O reduction in the Eastern Tropical North Pacific Ocean and found that incomplete denitrification in ODZs increases N2O accumulation and eventual efflux to the atmosphere. N2O is a potent greenhouse gas and Ward's research shows that the expanding ODZs in the global ocean may increase the amount of N2O entering the atmosphere.
Professional service
Ward has served on review panels of university graduate programs, institutional oceanography programs, and National Science Foundation funding programs.
Awards
Marie Tharp Award Lecture, Helmholz Center for Ocean Research, Kiel, Germany, (2016)
Charnock Lecturer, Southampton Oceanography Center, UK, (2015)
Woods Hole Oceanographic Institution Chemical Oceanography H. Burr Steinbach Scholar of (2015)
Rachel Carson Award Lecture, American Geophysical Union (2014)
Samuel A. Waxman Honorary Lectureship, Theobald Smith Society, (2014)
Procter & Gamble Award, American Society for Microbiology, (2012)
Fellow of the American Academy of Arts and Sciences, (2004)
Fellow of the American Geophysical Union, (2002)
Fellow of the American Academy of Microbiology, (1999)
Who's Who in American University Teachers, (1997)
G. Evelyn Hutchinson Medal, American Society of Limnology and Oceanography, (1997)
Distinguished Visiting Biologist, Woods Hole Oceanographic Institution, March (1996)
Selected publications
Community composition of nitrous oxide related genes and their relationship to nitrogen cycling rates in salt marsh sediments, Frontiers in Microbiology, 9: 170 (2018)
Denitrification as the dominant nitrogen loss process in the Arabian Sea., Nature, 461: 78-82 (2009)
Methane oxidation and methane fluxes in the ocean surface layer and in deep anoxic waters. Nature, 327: 226-229 (1987)
References
Living people
Year of birth missing (living people)
American women biochemists
Nitrogen cycle
Princeton University faculty
University of Washington College of the Environment alumni
Michigan State University alumni
Biogeochemists
American women oceanographers
Fellows of the American Academy of Microbiology
American women academics
21st-century American women
American oceanographers | Bess Ward | [
"Chemistry"
] | 1,044 | [
"Geochemists",
"Nitrogen cycle",
"Biogeochemistry",
"Biogeochemists",
"Metabolism"
] |
61,101,068 | https://en.wikipedia.org/wiki/Ulotaront | Ulotaront (; developmental codes SEP-363856, SEP-856) is an investigational antipsychotic that is undergoing clinical trials for the treatment of schizophrenia and Parkinson's disease psychosis. The medication was discovered in collaboration between PsychoGenics Inc. and Sunovion Pharmaceuticals (which was subsequently merged into Sumitomo Pharma) using PsychoGenics' behavior and AI-based phenotypic drug discovery platform, SmartCube.
Ulotaront is in phase III clinical trial for schizophrenia, phase II/III for generalised anxiety disorder and major depressive disorder and discontinued for narcolepsy and psychotic disorders.
Research has shown that ulotaront results in a greater reduction from baseline in the PANSS total score than placebo. Treatment with ulotaront, as compared with placebo, was also associated with an improvement in sleep quality. Ulotaront was awarded a Breakthrough Therapy designation due to its increased efficacy and greatly reduced side effects compared to current treatments.
Adverse effects
The adverse effect profile of ulotaront differs from that of other antipsychotics because its mechanism of action does not involve antagonism of dopamine receptors in the brain, which is responsible for the drug-induced movement disorders (like akathisia) that may occur with those agents. Some adverse events reported in preliminary clinical trials are somnolence, agitation, nausea, diarrhea, and dyspepsia.
Pharmacology
Pharmacodynamics
The mechanism of action of ulotaront in the treatment of schizophrenia is unclear. However, it is thought to be an agonist at the trace amine-associated receptor 1 (TAAR1) and serotonin 5-HT1A receptors. This mechanism of action is unique among available antipsychotics, which generally antagonize dopamine receptors (especially dopamine D2 receptor).
Ulotaront is a full agonist of the human TAAR1 with an of 140nM and an of 101.3%. It is also a partial agonist of the serotonin 5-HT1A receptor ( = 2,300nM; = 74.7%) and of the serotonin 5-HT1D receptor ( = 262nM; = 57.1%). Conversely, its activities at various other targets, such as various other serotonin receptors as well as adrenergic and dopamine receptors, are much less potent.
Ulotaront decreases basal locomotor activity in rodents and this effect was absent in TAAR1 knockout mice. It prevented the hyperlocomotion induced by the NMDA receptor antagonist phencyclidine (PCP). Conversely, ulotaront did not affect dextroamphetamine-induced hyperlocomotion. Similarly, it did not reverse apomorphine-induced climbing behavior.
Pharmacokinetics
The precise pharmacokinetic profile of ulotaront has not been reported, though the developer has suggested that the pharmacokinetic data supports once daily dosing.
Research
As of 2018, Sunovion, the maker of another antipsychotic called lurasidone (Latuda), is conducting clinical trials on ulotaront in partnership with the preclinical research company PsychoGenics. The U.S. Food and Drug Administration has granted ulotaront the breakthrough therapy designation. In addition to schizophrenia, ulotaront is also being studied for the treatment of psychosis associated with Parkinson's disease.
The Brief Negative Symptom Scale (BNSS) has been used to assess the effect of Ulotaront on the negative symptoms of schizophrenia.
In July 2023, the pharmaceutical company behind the drug announced that the drug had failed to outperform placebo in the treatment of acutely psychotic patients with schizophrenia, as measured by the PANSS.
See also
List of investigational antipsychotics § Monoamine receptor modulators
Ralmitaront
References
5-HT1A agonists
5-HT1D agonists
Amines
Antipsychotics
Experimental drugs developed for schizophrenia
TAAR1 agonists
Thiophenes | Ulotaront | [
"Chemistry"
] | 879 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
61,101,394 | https://en.wikipedia.org/wiki/Polarimeter%20to%20Unify%20the%20Corona%20and%20Heliosphere | Polarimeter to Unify the Corona and Heliosphere (PUNCH) is a future mission by NASA to study the unexplored region from the middle of the solar corona out to 1 AU from the Sun. PUNCH will consist of a constellation of four microsatellites that through continuous 3D deep-field imaging, will observe the corona and heliosphere as elements of a single, connected system. The four microsatellites were initially scheduled to be launched in October 2023, but were moved to launch alongside (rideshare) the SPHEREx space observatory on a Falcon 9 Block 5 rocket from Vandenberg Space Force Base on scheduled to liftoff on 27 February 2025.
On 20 June 2019, NASA announced that PUNCH and TRACERS were the winning candidates to become the next missions in the agency's Small Explorer program (SMEX).
PUNCH is led by Craig DeForest at the Southwest Research Institute (SwRI) in Boulder, Colorado. Including launch costs, PUNCH is being funded for no more than .
Mission
The stated primary objective of PUNCH is "to fully discern the cross-scale physical processes, from microscale turbulence to the evolution of global-scale structures, that unify the solar corona and heliosphere". In other words, the mission aims to understand how the solar corona becomes the solar wind.
The two specific objectives are to understand how coronal structures become the ambient solar wind, and to understand the dynamic evolution of transient structures in the young solar wind. The Principal Investigator, Craig DeForest, thinks that such closer study will also lead to a better understanding of the causes of solar weather events like coronal mass ejections (CMEs), which can damage satellites and disrupt electrical grids and power systems on Earth.
The more we understand what drives space weather and its interaction with the Earth and lunar systems, the more we can mitigate its effects – including safeguarding astronauts and technology crucial to NASA's Artemis program to the Moon.
Instruments
The mission configuration consists of a constellation of four observatories, each carrying one primary instrument.
The Narrow Field Imager (NFI) sits on only one spacecraft, and is an externally occulted visible-light coronagraph.
The Wide Field Imagers (WFIs) are side-looking heliospheric imagers with planar-corral baffles that sit on the remaining 3 spacecraft.
The NFI spacecraft also carries a student-built instrument, the Student Thermal Energetic Activity Monitor (STEAM). STEAM is a solid-state X-ray spectrometer that views the entire Sun as a point source, to study the physics of coronal heating and solar flares.
The fields of view (FoV) of the 3 WFIs overlap slightly with each other and with the NFI, and the instruments' operation is synchronized. The instruments operate through polarized Thomson-scatter imaging of the transition from corona to heliosphere. PUNCH integrates images from its constellation of small satellites into a global composite after each orbit, covering ~6 orders of magnitude dynamic range. Through a stream of these images, PUNCH achieves 3D feature localization and accurate deep field imaging. The mission builds on Cyclone Global Navigation Satellite System (CYGNSS) experience with smallsat constellations.
Data Acquisition
To accomplish its science objectives, PUNCH will acquire polarized white-light images over a composite 90° field of view centered on the Sun, i.e. from a few solar radii to 45° from the Sun in all directions. This poses many challenges in data reduction, meaning that the greatest technical challenge of the mission is in ground-processing the images acquired by the four spacecraft.
The PUNCH science objectives require measuring the faint sunlight reflected off electrons contained in the corona and solar wind (the extended K-corona). Ten degrees from the Sun, the K-corona is 1000x fainter than the background stars, requiring precise photometric calibration across the individual cameras, to measure and remove the background starfield, galaxy, and related features—which constitute 99.9% of the light incident on the cameras. The camera images are co-aligned to within 0.03 pixel RMS, requiring precise measurement of the optical distortion of each lens system. Point spread function effects, such as optical coma, are identified and removed in the PUNCH data reduction pipeline; and minor photometric errors introduced by data compression are also tracked and eliminated. Polarimetry of the K-corona is affected by the polarization of the starfield itself, which required developing a novel formalism to enable background subtraction while preserving linear polarimetry.
The primary PUNCH data product is background-subtracted, polarimetric images produced by the constellation on a 4 minute cadence; these images are made available to everyone via NASA's SDAC facility and the Virtual Solar Observatory.
Collaborations
SwRI is collaborating with the Naval Research Laboratory (NRL) and the Rutherford Appleton Laboratory in Oxfordshire, England, United Kingdom.
PUNCH, which will operate in low Earth orbit, will work in synergy with NASA's Parker Solar Probe and the ESA's Solar Orbiter.
See also
Explorer program
References
Solar space observatories
Proposed space probes
Solar telescopes
Space weather
NASA space probes
2025 in spaceflight
Explorers Program | Polarimeter to Unify the Corona and Heliosphere | [
"Astronomy"
] | 1,074 | [
"Space telescopes",
"Solar space observatories"
] |
61,102,454 | https://en.wikipedia.org/wiki/Helma%20Wennemers | Helma B. Wennemers (born 24 June 1969 in Offenbach am Main) is a German organic chemist. She is a professor of organic chemistry at the Swiss Federal Institute of Technology in Zurich (ETH Zurich).
Education
Helma Wennemers studied chemistry at the Goethe University Frankfurt, completing her diploma thesis with in 1993. She earned her PhD at Columbia University, New York in 1996, under the supervision of W. Clark Still, with a thesis "Encoded combinatorial chemistry: a tool for the study of selective intermolecular interactions." Between 1996 and 1998, she was a postdoctoral fellow at Nagoya University with Hisashi Yamamoto, before being appointed Bachem Assistant Professor at the University of Basel in 1999. She held this post until 2003, where she was promoted to associate professor. In 2011, she moved to ETH Zurich as a professor of organic chemistry.
Research
Wennemers' research focuses on proline-rich peptides.
Asymmetric Catalysis:
Wennemers led the development of tripeptides containing H-Pro-Pro-Xaa type sequences (Pro: proline, Xaa: any amine) as organocatalysts for C–C bond formations based on an enamine mechanism. High reactivity, stereo- and chemoselectivity for aldol or conjugate addition reactions can be achieved by varying the absolute configuration of the single amino acids as well as the functional group of the Xaa residue. The modularity of the peptides enabled creation of catalysts capable of catalyzing the conjugate addition reactions of aldehydes to nitroolefins with as little as 0.05 mol% of tripeptidic catalyst.
She also worked on other organocatalyzed transformations. Inspired by natural polyketide synthases—which use malonic acid half thioesters (MAHTs) as thioester enolate equivalents — she developed organocatalytic methods for stereoselective addition reactions of MAHTs (and protected variants monothiomalonates, MTMs) to electrophiles using cinchona alkaloid derived catalysts. The introduction of fluorinated MAHTs and MTMs allowed for the stereoselective introduction of fluorine substituents in fluoroacetate aldol reactions as well as further addition reactions to imines and nitroolefins.
Chemical Biology:
In chemical biology, Wennemers uses larger proline-rich peptides, such as collagen model peptides or oligoprolines, for applications such as tumor targeting, cell penetration or drug delivery. She utilized Cγ-functionalized proline derivatives for the functionalization and stabilization of short-chained collagen triple helices. Further, she introduced aminoproline and γ-azaproline as pH-sensitive probes to tune the conformational stability of the collagen triple helix by pH change. In the field of cell penetrating peptides (CPPs), Wennemers showed that preorganization of cationic charges along an oligoproline backbone enhanced the cellular uptake of CPPs compared to more flexible oligoarginines with undefined charge display. Moreover, the oligoproline-based CPPs demonstrated a defined nuclear localization and high proteolytic stability as well as low cytotoxicity.
Synthetic Materials:
Wennemers utilizes peptides to control the morphology of nanostructured materials for generation of ordered mesoscopic materials. She developed tripeptides for the size-controlled generation of mono-disperse, water-soluble silver-, palladium-, platinum-, and gold nanoparticles. Recently, she reported peptide‐stabilized platinum nanoparticles that have greater toxicity against hepatic cancer cells (HepG2) than against other cancer cells and non‐cancerous liver cells. Wennemers also explored conjugates of oligoprolines and π-conjugated systems that form hierarchical self-assemblies with diverse morphologies (e.g. nanofibers, nanorods, nanosheets). She used such a conjugate to prepare the first example of an extended triaxial supramolecular weave held together through the interplay of weak non-covalent interactions.
Awards
Wennemers work was recognized by the Leonidas Zervas Award of the European Peptide Society (2010), the Pedler Award of the Royal Society of Chemistry (2016), the Inhoffen Medal (2017), the Netherlands Scholar Award for Supramolecular Chemistry (2019) and the Arthur C. Cope Scholar Award (2020).
References
External links
Homepage of the Wennemers group''
1969 births
Living people
People from Offenbach am Main
Academic staff of Goethe University Frankfurt
Academic staff of the University of Basel
Academic staff of ETH Zurich
German expatriates in Switzerland
German women chemists
20th-century German chemists
21st-century German chemists
20th-century German women scientists
21st-century women scientists
German organic chemists
20th-century German women
21st-century German women | Helma Wennemers | [
"Chemistry"
] | 1,055 | [
"Organic chemists",
"German organic chemists"
] |
61,103,511 | https://en.wikipedia.org/wiki/Nature%20Reviews%20Materials | Nature Reviews Materials is a monthly peer-reviewed scientific journal published by Nature Portfolio. It was established in 2016. The journal covers all topics within materials science. It presents reviews and perspectives, which are commissioned by the editorial team. The editor-in-chief is Giulia Pacchioni.
According to the Journal Citation Reports, the journal has a 2021 impact factor of 76.679, ranking it 1st out of 345 journals in the category "Materials Science, Multidisciplinary" and 1st out of 109 journals in the category "Nanoscience & Nanotechnology".
References
External links
Nature Research academic journals
Materials science journals
Monthly journals
English-language journals
Academic journals established in 2016
Review journals | Nature Reviews Materials | [
"Materials_science",
"Engineering"
] | 142 | [
"Nanotechnology journals",
"Materials science journals",
"Materials science"
] |
71,937,299 | https://en.wikipedia.org/wiki/HD%2032820 | HD 32820, also known as HR 1651, is a yellowish-white hued star located in the southern constellation Caelum, the chisel. It has an apparent magnitude of 6.3, placing it near the limit of naked eye visibility. The object is located relatively close at a distance of 103 light years based on parallax measurements from Gaia DR3, but is receding with a heliocentric radial velocity of .
HD 32820 has a stellar classification of F8 V, indicating that it is an ordinary F-type main-sequence star that is generating energy via hydrogen fusion at its core. It has 125% the mass of the Sun and 133% of its radius. It radiates double the luminosity of the Sun from its photosphere at an effective temperature of . HD 32820 is said to be 3.46 billion years old, slightly younger than the Sun, and has a near solar iron abundance. The star spins modestly with a projected rotational velocity of and is chromospherically inactive
References
F-type main-sequence stars
32820
23555
1651
CD-41 01690
Caeli, 27
Caelum | HD 32820 | [
"Astronomy"
] | 239 | [
"Caelum",
"Constellations"
] |
71,937,657 | https://en.wikipedia.org/wiki/Journal%20of%20Materials%20Research | The Journal of Materials Research is a peer-reviewed scientific journal which covers research in materials science. The journal was established in 1986 and is the official journal of the Materials Research Society. The journal is published by Springer Science+Business Media and the editor-in-chief is Ramamoorthy Ramesh (University of California, Berkeley).
Abstracting and indexing
The journal is abstracted and indexed in:
EBSCO databases
Ei Compendex
Science Citation Index Expanded
Scopus
According to the Journal Citation Reports, the journal has a 2021 impact factor of 2.909.
References
External links
English-language journals
Academic journals established in 1986
Springer Science+Business Media academic journals
Semi-monthly journals | Journal of Materials Research | [
"Materials_science"
] | 142 | [
"Materials science stubs",
"Materials science journals",
"Materials science journal stubs"
] |
71,937,717 | https://en.wikipedia.org/wiki/Synchrotron%20radiation%20circular%20dichroism%20spectroscopy | Synchrotron radiation circular dichroism spectroscopy, commonly referred to as SRCD and also known as VUV-circular dichroism or VUVCD spectroscopy, is a powerful extension to the technique of circular dichroism (CD) spectroscopy, often used to study structural properties of biological molecules such as proteins and nucleic acids. The physical principles of SRCD are essentially identical to those of CD, in that the technique measures the difference in absorption (ΔA) of left (AL) and right (AR) circularly polarized light (ΔA=AL-AR) by a sample in solution. To obtain a CD(SRCD) spectrum the sample must be innately optically active (chiral), or, in some way be induced to have chiral properties, as only then will there be an observable difference in absorption of the left and right circularly polarized light. The major advantages of SRCD over CD arise from the ability to measure data over an extended wavelength range into the vacuum ultra violet (VUV) end of the spectrum. As these measurements are utilizing a light source with a higher photon flux (quantity of light stricking a given surface area) than a bench-top CD machine it means data are more accurate at these extended wavelengths because there is a larger signal over the background noise (the signal-to-noise ratio) and, generally, less sample is needed when recording the spectra and there is more information content available in the data. Many beamlines now exist around the world to enable the measurement of SRCD data.
Origins
Extending the wavelength range for CD experiments had been both considered and instigated as far back as 1970. Three research groups had created their own "in-house" CD machines, with specialist lamps as their light source, to enable measurements in this range. Synchrotron radiation (SR) had been proposed for use as the light source at a meeting in Brookhaven National Laboratory on Long Island in 1972, however, it took a few years more before this came to fruition. Two research papers in 1980 reported the collection of CD data using SR as the light source for the experiments. Specifically, spectra were obtained in wavelength regions into the VUV range, from ~100 nanometers (nm) to ~200 nm, largely unavailable to laboratory-based bench-top spectrophotometers. Sutherland et. al. focussed on the development of a versatile spectrophotometer capable of measuring CD, amongst other properties, in the VUV region of the spectrum, while Snyder and Rowe collected CD data from a small organic compound in the wavelength range 130.5 nm to 205 nm.
Simplified overview of an SRCD beamline setup
As shown in the diagram, a number of baffles are used throughout to remove possible stray light being reflected off the sides of the beamline tube. The use of only one mirror minimizes the loss of photon flux which is most important in the VUV region where reflectivity is poor relative to the visible wavelength range.
The first constructed SRCD beamlines initially tried to utilize the intrinsic properties of the SR radiation produced, whereby there exists a "central" linearly-polarized component with, above and below this, equally opposing regions of circularly-polarized components. The premise for this was that the overall signal produced from a chiral sample would be enhanced by the absorption difference (the signal) derived from these circularly polarized features of the beam. In an ideal situation this approach would work; however, this setup was modified such that all beamlines now include a linear polarizer (as shown) to remove these circularly polarized components. This was because even the minutest of movements in beam position (beam drift) led to unequal matching of the contributions of the circularly polarized components striking the sample and this, in turn, meant the SRCD signal produced was inaccurate and unreliable; often being irreproducible as a result.
Whereas cCD machines are purged throughout with nitrogen to minimize the absorption by oxygen of the light from the source xenon arc lamp, in an SRCD arrangement the beam passes through a calcium fluoride (CaF2), or similar "VUV-wavelengths transparent", window where everything before this point is in vacuum, and everything beyond is in nitrogen. The beam interacts with a photoelastic modulator (PEM) which consequently produces an alternating right- then left-circularly polarized beam and these now interact with the sample. The resultant absorption difference by the sample is measured and amplified by a photomultiplier tube (PMT) and from this the SRCD spectrum is recorded.
The wavelength range that is utilized for SRCD studies is typically in the UV to VUV region and can go to below this; potentially from ~100 nm, up to the visible region, ~400 nm. The exact range over which data can be collected relies on the beamline set up, the sample preparation and the wavelength range of the PMT detector used. One of the primary factors limiting the lower wavelength cut off is the sample usually being in solution as a large water absorption band exists centred ~167 nm. This high absorption background swamps any possibility of measuring the very small CD difference signal, although use of deuterated water (D2O) as the solvent reduces the solvent absorption increasing the lower wavelength data collection range by ~10 nm. Removing the solvating water completely, creating a film as a result, means that data can be recorded to significantly lower wavelengths, down to around ~130 nm.
Advantages over conventional CD machines
The main advantages for SRCD over lab-based cCD machines arise from the use of the synchrotron light emission as the source. A number of biologically interesting absorption bands are found in the region between ~170 nm and ~350 nm. For proteins these come from their secondary and tertiary structures, while structural bands for nucleic acids, (DNA and RNA), and saccharides are also located in this region. However, for cCD machines the photon flux from the source reduces by around two orders of magnitude in the wavelength range from 250 nm down to 180 nm, exactly in the region of most significance for these biological molecules. By contrast, typically, the photon flux for an SRCD beamline in this region is at least three orders of magnitude higher than a cCD machine, retaining that level down to ~150 nm. The increased flux means the measured signals from the sample will be increased relative to the background noise, so there is a significant improvement in the signal-to-noise ratio of the sample. This will improve the accuracy of the data recorded meaning interpretation can be undertaken with more confidence in the results. A further advantage of the increased flux is that the concentration of the sample can be reduced while still retaining a significant increase in signal strength, so samples that are difficult to produce in quantity have more chance of producing usable CD data from SRCD rather than a cCD machine. Increasing the lower wavelength range provides more spectral data for analysis which means there is more information content available in that data, meaning that more parameters, here secondary structure features in the protein structure, can be accurately determined.
Technique growth and development
While the first reports of its use dated to 1980, it was a further two decades before the technique of SRCD took off largely due to the work of Bonnie Wallace at Birkbeck College, University of London. From around 2000, her aims in the field focused on both enhancing the collection of quality data through technical improvements, and on demonstrating "proof-of-principle" application studies, illustrating the novel information that SRCD offers. The construction on the Synchrotron Radiation Source (SRS) of the CD12 beamline at Daresbury Laboratory, opened in 2005 under the auspices of the Centre for Protein and Membrane Structure and Dynamics (CPMSD) of which Wallace was the Director, represented the first of the new, dedicated, second-generation SRCD beamlines. It was quickly identified that the high photon flux from CD12 was causing denaturation of the protein sample but that this was resolvable by reducing the sample area being irradiated. Later studies have identified the flux threshold limits that induce SRCD protein denaturation. The input from the Wallace lab to the early years of SRCD development also included the introduction of calibration and standardization of SRCD and cCD spectrophotometers, the creation of software to process the spectral data using CDtool, and CDtoolX, and to analyse the data using DichroWeb, and the generation of reference data sets of proteins to support these data analyses. Additionally, her lab produced sample cells with reduced pathlengths, and using material, (CaF2), transparent to VUV radiation which significantly enhanced the collection of data into the SRCD lower wavelength regions.
New SRCD beamlines were constructed on various synchrotrons around the world. ring, in the Department of Physics and Astronomy of Aarhus University in Denmark, became a dedicated second-generation synchrotron in 2005. Ultimately this ring had two SRCD beamlines, UV1 and CD1, which migrated to the new third-generation ring, ASTRID2, in 2013/14, as AU-UV and AU-CD. SOLEIL synchrotron, near Paris, France, commissioned a dedicated SRCD beamline, DISCO, around 2005. At Hiroshima Synchrotron Radiation Center, also known as HiSOR, a VUVCD beamline was constructed over the same period, while a little later in 2009, an SRCD beamline was commissioned in Beijing, China. This particular beamline is unique in that the synchrotron which acts as its light source is also the electron carrying ring of the Beijing Electron Positron Collider. The SRS closed in 2008 being superseded in the UK by the Diamond Light Source on which an SRCD beamline opened for use in 2010. With the SRS closure the CD12 SRCD beamline was moved to, and installed on, the ANKA Synchrotron Radiation Facility, (now called KARA), part of Karlsruhe Institute of Technology (KIT), in Karlsruhe, Germany. This beamline opened for users in 2011 but was closed in 2021. Currently under construction (as of June 2023) on the Sirius synchrotron light source in Campinas, Brazil, is a new SRCD beamline, CEDRO.
Examples of applications
Highlighting a few of the published works that have employed SRCD in their research studies best illustrates the power of this technique.
Improved conformational analysis due to increased signal-to-noise ratio
Cataracts are the primary cause of blindness in humans and mutations in one particular protein, γD-crystallin, have been linked to a number of congenital forms of this disease. An amino acid mutation, proline (P) to threonine (T) at position 23 of the polypeptide chain has been linked to at least four different forms of this ailment. SRCD investigations were conducted on the wild-type protein and two variants, the P23T mutant found in the disease, and a related modification, P23S (proline to serine, a chemically similar amino acid to threonine), to establish the nature of the cause of cataract formation. Two possible reasons were suggested as the causative factor; the reduced solubility of the mutant protein, or an instability in the structure of the protein being introduced by the mutation. Significantly, because the mutant had limited solubility, lab-based CD machines were only able to provide very noisy spectra and the data were uninterpretable as a result. However, the SRCD spectra produced had very low noise associated with their data, including the mutant, and showed clearly that the structures of the wild-type, the mutant, and the related protein all had very similar conformations. These data also established that the mutant retained stability to thermal denaturation, very similar to that of the wild-type protein. The data confirmed that the causative factor for the cataracts was the reduction in solubility associated with the P23T mutation and not changes in the stability of the protein.
Because of a high degree of flexibility, it had proven difficult to determine the structure of the extramembranous C-terminal domain of bacterial voltage-gated sodium channels. Using a series of synthesised channels where this C-terminal domain had been truncated, in some cases by a single amino acid difference between the constructs, the Wallace lab used SRCD to successfully identify the structure of this region.
Intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs)
Intrinsically disordered proteins (IDPs) have very limited innate structure in solution but gain shape specifically when interacting with partner molecules such as proteins or RNA; however, their resultant structure is often dictated by this interaction. In addition, some proteins have sections of sequence without structure, termed intrinsically disordered regions (IDRs), that also gain structure on interaction. Having different shapes with different partners means they are functionally, as well as structurally flexible, making them centrally important to signalling pathways and as regulation/control factors for example. IDPs (and IDRs if capable of being isolated from the rest of the protein) have a distinct SRCD spectral appearance in solution which means that changes in their spectra that arise through interactions offer an ideal opportunity to gain insight into what is happening both structurally and functionally. In addition, SRCD studies have demonstrated that when the solvating water is removed from these proteins, generating a film, there is a gain in structure and more CD transition bands can be measured into the lower VUV wavelength region because the water absorption band is not present
Myelin is the insulating sheath that is formed in the central (CNS) and peripheral nervous systems (PNS) to surround nerve cell axons thereby increasing and maintaining the electrical impulse, the action potential, sent along them. Formed mostly of lipids, there are specific proteins within the myelin components whose roles are to structure the myelin into linked layers. Two of these proteins are myelin basic protein (MBP), an IDP primarily in the CNS, and myelin protein zero (P0) which contains an IDR section (P0ct) and is key within the PNS. MBP and P0ct were employed in a study which used SRCD data as a key factor to establish if there was any significance to the predictions of their IDP and IDR protein structures generated by Alphafold2, an artificial intelligence program developed by DeepMind. PDB2CD, a package that generates SRCD spectra from protein atomic coordinates, was used to calculate spectra from the Alphafold2 structures, and these spectra were then compared against SRCD experimental spectra collected from the MBP and P0ct proteins in various ambient conditions; solution, detergent and lipid-bound states. The study reported that from the SRCD comparisons, the structures predicted by Alphafold2 for MBP and P0ct bore a strong resemblance to those when they were bound to the lipid membrane.
Sugar modification of protein SRCD signals
One major feature found in protein structures is the addition of sugars (glycosylation) to specific amino acid residues by post translational modification. Complex sugar structures can be connected to these sites, and this can substantially modify the properties of these proteins, a main reason for their presence. Attached sugars can assist in folding some proteins to their correct shape; so, affecting a proteins’ structure is a possible outcome. SRCD is ideally well suited to determining any conformational differences that might arise from different ambient environments directly because of the extended wavelength range into the VUV region which provides greater information content. However, attached sugars can contribute to the SRCD signal because their transitions are located more towards the VUV end of the spectrum. This means that their presence can cause a problem in obtaining an accurate measure of the secondary structure content of the protein as a result. Matsuo. and Gekko produced the landmark study of VUVCD spectra of selected saccharides, thereby demonstrating that glycoproteins would have a contribution to their spectra from their sugar content. From this and further studies they demonstrated that the SRCD spectral characteristics that arose from sugars could be attributed to many factors within their conformations: the configuration of the hydroxyl group about the C1 atom of the saccharide (alpha or beta conformation, or almost axial or equatorial to the plane of the sugar ring respectively), the axial or equatorial positioning of the remaining hydroxyl groups, the trans or gauche nature of the C5 hydroxymethyl group, and the glycosidic linkage (either 1-4 or 1-6) between sugar monomers. Utilising this information, the Wallace group investigated the glycosylation of the voltage-gated sodium channel in experiments that relied on the fact that a CD(SRCD) spectrum of a mixture of components is the sum of all those components present. The aim was to establish if there were differences in the three-dimensional structure of the channel with and without sugars attached to the structure; did glycosylation play any significant role in the function of these channels when sugars were attached? Three experimental sets of SRCD spectra were collected; the non-glycosylated and glycosylated channel structures and a further one of the isolated sugar components that combined to form those attached to the channel. Taking away the spectrum of the non-glycosylated channel from that of the glycosylated they demonstrated that the resultant difference spectrum corresponded to that of the sugar components. This meant that there were no structural differences between the glycosylated and non-glycosylated channel structures, so sugar attachment played no key role in their function
Conformational changes of globular proteins at the oil-water interface
First studied in 2010 via this method, a recent investigation used SRCD to examine the differences in structure in solution and when at the oil-water interface, of peptides derived from seaweed, bacteria and potatoes as potential emulsifying agents. Of these studied, the peptide from bacteria proved to be the most effective at being both an emulsifying agent and stabilising antioxidant compound.
Existing beamlines
A number of SRCD beamlines exist, or are being constructed (), around the world as listed in the table.
As of 2022 components from former SRCD beamline CD12 (on KARA) are now installed on the DISCO beamline
This facility also runs as part of the Beijing Electron Positron Collider (BEPC)
Two modules (A and B) exist on this beamline
This beamline is under construction and received its "first light" as of June 2023
References
Spectroscopy | Synchrotron radiation circular dichroism spectroscopy | [
"Physics",
"Chemistry"
] | 3,880 | [
"Instrumental analysis",
"Molecular physics",
"Spectroscopy",
"Spectrum (physical sciences)"
] |
71,937,871 | https://en.wikipedia.org/wiki/HD%20115088 | HD 115088, also known as HIP 64951, is a star located in the southern circumpolar constellation Chamaeleon. It has an apparent magnitude of 6.33, placing it near the limit for naked eye visibility. Based on parallax measurements from the Gaia spacecraft, the object is estimated to be 412 light years distant. At that distance, its brightness is diminished by 0.37 magnitudes due to interstellar dust.
HD 115088 has a stellar classification of B9.5/A0 V — intermediate between a B9.5 and A0 main sequence star. It has 2.85 times the mass of the Sun and double the radius of the Sun. It radiates 62.5 times the luminosity of the Sun from its photosphere at an effective temperature of , giving it a bluish-white hue. It is estimated to be 244 million years old, having completed 52.5% of its main sequence lifetime.
References
B-type main-sequence stars
A-type main-sequence stars
115088
064951
CD-79 00519
Chamaeleontis, 45
Chamaeleon | HD 115088 | [
"Astronomy"
] | 244 | [
"Chamaeleon",
"Constellations"
] |
71,938,129 | https://en.wikipedia.org/wiki/%C3%81lvaro%20R%C3%ADos%20Poveda | Álvaro Ríos Poveda (born 3 February 1974, Cali, Colombia) is a Colombian electronic engineer, university professor, and researcher who specializes in biomedical engineering and mechatronics. He has performed research on myoelectric prostheses, sensory feedback, and bionic vision technologies.
Early life and education
He began his studies at San Juan Berchmans school in Cali, Colombia.
Ríos earned an undergraduate degree in Electronic Engineering at Pontifical Xavierian University and completed his master's at Simon Bolivar University and doctorate studies at USF in Biomedical Engineering. Along with that, he obtained an MBA from ISEAD. His professional career began with research in neural prostheses and bionics systems. Ríos researched biomedical engineering, artificial intelligence, and robotics in control systems.
Career
Ríos is a researcher and university professor in undergraduate and postgraduate studies in Europe and Mexico. From a young age, his interest had grown into motor limitations.
In 1996, he developed prosthetic systems that allow patients to have greater limb functionality while ensuring accessibility for these systems in developing countries.
In 1997, a sensory feedback system for prostheses was presented at France's World Congress on Biomedical Engineering. Ríos's public work includes myoelectric prosthesis with sensory feedback, presented at MEC'02: The Next Generation. His work mainly aims of his work is to control prosthetics more naturally, utilizing artificial intelligence, neural control, machine learning, and gesture control.
Research
He has remained a member of the Publications Committee of the International Federation of Medical and Biological Engineering and a founding member of the Colombian Association of Biomedical Engineering. Since its inception in 2017, Ríos has been participating at every CBS IEEE International Conference on Bionic Systems and Cyborg and giving guest participation at IEEE's CBS 2017. Later in 2018, he represented the Latin American region at a conference on Upper Limb Prosthesis. Since then, Ríos has remained Chairman for the region of the Americas at the 2020 IEEE CBS and has also been working with World Health Organization, a member of Global Cooperation on Assistive Technology. He also established HAT (Human Assistive Technologies), a bionics company based in Mexico City. At HAT, a C-Hand was developed, which is a bionic prosthesis with sensory feedback and gesture control, and is a bionic arm designed for smart cities.
Recognition
Gold Cross Degree at (Council of Cali 2022)
Bristol Honor 2014 (Who's who honor)
Publications
Rios Poveda, A. (2002). Myoelectric prostheses with sensorial feedback. Myoelectric Symposium.
3. Poveda, AER (2001). Microcontrolled system for the development of myoelectric prostheses with sensory feedback (Doctoral dissertation, Pontificia Universidad Javeriana. Cali).
ios, Alvaro (1997). "Microcontroller system for Myoelectric prosthesis with sensorial feedback". World Congress on Medical Physics and Biomedical Engineering: XVIII International Conference on Medical and Biological Engineering and XI International Conference on Medical Physics. ISSN 0140-0118.
References
Living people
1974 births
Colombian engineers
Biomedical engineers
Bionics
Prosthetics
Pontificia Universidad Javeriana alumni
People from Cali | Álvaro Ríos Poveda | [
"Engineering",
"Biology"
] | 669 | [
"Bionics"
] |
71,938,528 | https://en.wikipedia.org/wiki/OY%20Arae | OY Arae, also known as Nova Arae 1910, is a nova in the constellation Ara. It was discovered by Williamina Fleming on a Harvard Observatory photographic plate taken on April 4, 1910. At that time it had a magnitude of 6.0, making it faintly visible to the naked eye under ideal observing conditions. Examination of earlier plates showed that before the outburst it was a magnitude 17.5 object, and by March 19, 1910, it had reached magnitude 12.
OY Arae is considered to be a moderately fast nova, because it faded by 3 magnitudes during the 83 days after discovery. The light curve shows a secondary maximum in June 1910. The first spectrum of the nova was obtained on July 5, 1910, and resembled that of a gaseous nebula. An optical identification of the quiescent nova was made in 1994, and spectra taken at that time showed strong Balmer lines in emission atop a blue continuum.
All novae are binary stars, with a "donor" star orbiting a white dwarf. The two stars are so close to each other that material is transferred from the donor to the white dwarf. Because the distance between the two stars is comparable to the radius of the donor star, novae are often eclipsing binaries, and OY Arae does show eclipses. The primary eclipse, in which the donor star eclipses the white dwarf and its accretion disk, are about 2 magnitudes deep and last less than 30 minutes. The orbital period is 3.73118 hours. The mass of the white dwarf is , and the mass of the donor star is . The two stars are separated by .
Most of the luminosity of the system is produced by the disk of material being stripped from the donor star. This is estimated to be 7 magnitudes brighter than the donor star itself, with the white dwarf being even fainter. The absolute magnitude of the system is given as +4.6, but this value is distorted by the shape of the disk, seen nearly edge-on. A mean absolute magnitude adjusted for viewing angle is +3.6.
References
Novae
Ara (constellation)
Arae, OY
1910 in science | OY Arae | [
"Astronomy"
] | 445 | [
"Novae",
"Astronomical events",
"Constellations",
"Ara (constellation)"
] |
71,939,967 | https://en.wikipedia.org/wiki/Fermi%E2%80%93Dirac%20prime | In number theory, a Fermi–Dirac prime is a prime power whose exponent is a power of two. These numbers are named from an analogy to Fermi–Dirac statistics in physics based on the fact that each integer has a unique representation as a product of Fermi–Dirac primes without repetition. Each element of the sequence of Fermi–Dirac primes is the smallest number that does not divide the product of all previous elements. Srinivasa Ramanujan used the Fermi–Dirac primes to find the smallest number whose number of divisors is a given power of two.
Definition
The Fermi–Dirac primes are a sequence of numbers obtained by raising a prime number to an exponent that is a power of two. That is, these are the numbers of the form where is a prime number and is a non-negative integer. These numbers form the sequence:
They can be obtained from the prime numbers by repeated squaring, and form the smallest set of numbers that includes all of the prime numbers and is closed under squaring.
Another way of defining this sequence is that each element is the smallest positive integer that does not divide the product of all of the previous elements of the sequence.
Factorization
Analogously to the way that every positive integer has a unique factorization, its representation as a product of prime numbers (with some of these numbers repeated), every positive integer also has a unique factorization as a product of Fermi–Dirac primes, with no repetitions allowed. For example,
The Fermi–Dirac primes are named from an analogy to particle physics. In physics, bosons are particles that obey Bose–Einstein statistics, in which it is allowed for multiple particles to be in the same state at the same time. Fermions are particles that obey Fermi–Dirac statistics, which only allow a single particle in each state. Similarly, for the usual prime numbers, multiple copies of the same prime number can appear in the same prime factorization, but factorizations into a product of Fermi–Dirac primes only allow each Fermi–Dirac prime to appear once within the product.
Other properties
The Fermi–Dirac primes can be used to find the smallest number that has exactly divisors, in the case that is a power of two, . In this case, as Srinivasa Ramanujan proved, the smallest number with divisors is the product of the smallest Fermi–Dirac primes. Its divisors are the numbers obtained by multiplying together any subset of these Fermi–Dirac primes. For instance, the smallest number with 1024 divisors is obtained by multiplying together the first ten Fermi–Dirac primes:
In the theory of infinitary divisors of Cohen, the Fermi–Dirac primes are exactly the numbers whose only infinitary divisors are 1 and the number itself.
References
Prime numbers
Integer sequences | Fermi–Dirac prime | [
"Mathematics"
] | 621 | [
"Sequences and series",
"Integer sequences",
"Mathematical structures",
"Recreational mathematics",
"Prime numbers",
"Mathematical objects",
"Combinatorics",
"Numbers",
"Number theory"
] |
71,943,261 | https://en.wikipedia.org/wiki/Noboru%20Tokita | Noboru Tokita (February 20, 1923 - October 31, 2014) was a Uniroyal and later Cabot scientist known for his work on the processing of elastomers.
Personal
Tokita was born in Sapporo, Japan in 1923. He met his wife Noriko while on an exchange program at Duke University. They married and decided to stay in the United States. He was a close colleague of 2009 Charles Goodyear Medal winner James White, introducing White to his future wife Yoko Masaki.
Education
Tokita completed BS degree at Tokyo University in 1948, and his Ph.D. in physics and chemistry in 1957 at the University of Hokkaido.
Career
He began his professional career in 1954 as a professor of Applied Physics at Waseda University in Tokyo. He held this position until 1960 when he came to the United States on an exchange program with Duke University. At Duke, he taught polymer rheology. In the early 1960s Tokita joined the U. S. Rubber Company in New Jersey, later Uniroyal, working there for 30 years on elastomer processing. He later joined Uniroyal Goodrich Tire Company in Akron in a research role. He joined Cabot Corporation in Billerica in 1990. During his career he produced 9 U.S. Patents. His most cited scientific article treated the subject of morphology formation in elastomer blends.
Awards
1994 - Melvin Mooney Distinguished Technology Award from Rubber Division of the ACS
References
1923 births
2014 deaths
Polymer scientists and engineers
Scientists from Sapporo
University of Tokyo alumni
Hokkaido University alumni
Academic staff of Waseda University
Duke University faculty
Japanese emigrants to the United States
Physical chemists | Noboru Tokita | [
"Chemistry",
"Materials_science"
] | 343 | [
"Polymer scientists and engineers",
"Physical chemists",
"Polymer chemistry"
] |
71,943,727 | https://en.wikipedia.org/wiki/Stina%20Stenhagen | Stina Lisa Stenhagen (née Ställberg; 4 December 1916 – 26 March 1973) was a Swedish biochemist who was active in the fields of medical chemistry and chemical ecology. Together with her husband she carried out groundbreaking research into the chemical composition of tubercular bacteria. In 1963, she was appointed professor of medical chemistry at Gothenburg University, so becoming the institution's first female professor. She and her colleagues later applied gas chromatography and mass spectrometry to investigate how pheromones allow communications between insects as well as between insects and plants, developing interest in a field which became known as chemical ecology.
Early life, education and family
Born in Norrköping on 4 December 1916, Stina Ställberg was the daughter of the school principal Johan Alfred Ställberg and his wife Anna Emilian née Swensson. After qualifying for her school leaving certificate in Norrköping in 1936, she was admitted to Uppsala University where she graduated in medicine in 1939. She was then employed as an assistant in the university's medical chemistry department where she met Einar Stenhagen whom she married in 1942. The couple had three children.
Career
Together with her husband, Stina Stenhagen undertook research on the chemical composition of tubercular bacteria, initially concentrating of the chemical and physical properties of the fatty acids and their relationship to changes in the tissues. In particular, she published the results of her research in a thesis titled "Undersökning över optiskt aktiva former av högre fettsyror med förgrenade kolkedjor" (Investigation of optically active forms of higher fatty acids with branched carbon chains) for which she was promoted to the grade of docent in 1961. The same year, both she and her husband were awarded the Swedish Medical Society's Jubilee Prize for their work on the chemical composition of tubercular bacteria.
In 1952, Stina Stenhagen became assistant professor of medical chemistry at Gothenburg's Medicinska högskolan (medical college) where she continued her research and became an enthusiastic teacher. In 1960, she was granted an honorary doctorate and became professor of medical chemistry, so becoming the first female professor at Gothenburg University. Her research turned to pheromones which are responsible for chemical communication signals between insects and plants. Together with the entomologist , she applied gas chromatography and mass spectrometry to her investigation of the structure of their active chemical compounds.
Stina Stenhagen died on 26 March 1973 in Mölndal.
References
1916 births
1973 deaths
People from Norrköping
Swedish biochemists
Women biochemists
Swedish ecologists
Women ecologists
University of Gothenburg alumni
Academic staff of the University of Gothenburg
20th-century Swedish women scientists
20th-century Swedish biologists
20th-century Swedish chemists
Uppsala University alumni | Stina Stenhagen | [
"Chemistry"
] | 578 | [
"Biochemists",
"Women biochemists"
] |
71,943,827 | https://en.wikipedia.org/wiki/Right%20To%20Know | Right To Know is a non profit support project for those who discover via genealogical genetic testing that their lineage is not what they had supposed it to be due to family secrets and misattributed parentage, thus raising existential issues of adoption, race, ethnicity, culture, rape, etc.
See also
Genealogy
Genetic testing
External links
Right To Know - Your Genetic Identity
References
Organizations established in 2022
2022 establishments in the United States
Genetics | Right To Know | [
"Biology"
] | 90 | [
"Genetics"
] |
71,944,173 | https://en.wikipedia.org/wiki/IJP%20The%20Book%20of%20Surfaces | IJP the book of surfaces is a book by George L. Legendre, with a foreword by Mohsen Mostafavi.
Overview
IJP the Book of Surfaces was released in 2003 by the publishing arm of the London-based Architectural Association School of Architecture. The book features six essays on the notion of surface written from an architectural, philosophical, literary, mathematical, and computational angle, as well as several lighter asides ranging from cookery to poetry. These threads have been given a particular typographic and graphic design treatment meant to weave them together into a continuous narrative.
Background and literary references
The book addresses some significant developments of the decade, such as the explosion of computational tools; the emergence of the 3D surface as an architectural signifier of the Digital Revolution; the profession's fascination with the formal possibilities of surface cladding; and the rise of innovative manufacturing technologies. It can be compared to contemporary titles like Mohsen Mostafavi’s and David Leatherbarrow’s Surface Architecture, an essay on the phenomenology of architectural façades, and Ellen Lupton’s collection Skin: Surface, Substance + Design, which explores the working metaphor of artificial skin in Materials science, fashion and the visual arts. By comparison, Illa Berman notes that IJP the Book of Surfaces withdraws from external cultural currents and their contexts and emerges from within the formal and computational specificity of the surface itself. As a piece of writing, it is indebted to the literary school Oulipo. Its treatment of one theme as a collection of vignettes written in different voices (linguistic, mathematical, computational, mock-literary, and pop-cultural) nods back to Raymond Queneau’s 1947 Exercises in Style, in which the same trivial event is told and re-told in different idioms.
Form and content
In keeping with the literary/mathematical spirit of Oulipo, layout, typography, and pagination form an integral part of the book's thesis. The pagination taps the formal affinity between a publisher’s book spread and a mathematician's surface, both of which draw on the concept of mathematical matrix. Similar mathematical references apply to the title of the work, which combines 'i' and 'j', two symbols commonly used in matrix algebra, with the symbol 'p' (for point), introduced by the author in reference to Euclidean space.
Reception
The book’s argument and restrained use of computer graphics by the standards of the day (dominated then as now by computer-generated renderings) elicited a mixed reception. Historians and theorists noted its withdrawal from the wider cultural context, its consistent argument, graphic sobriety, and theoretical reach. Some readers noted its lack of engagement with other pressing issues of the day, such as sustainability and ecology, as well as its blank and solipsistic tone, occasionally questionable syntax, and pedestrian graphic design. The book's reception may have reflected disagreements in the architectural community at the time over the meaning of innovation and the finality of computational tools. After 2015, similar disagreements arose between the trade press and the self-identifying avant-garde movement of architectural parametricism. Legendre has since distanced himself from the broader cultural claims of the movement).
See also
References
Architectural Association School of Architecture
Architecture books
Mathematics books
Computer books
Design books | IJP The Book of Surfaces | [
"Technology"
] | 682 | [
"Works about computing",
"Computer books"
] |
71,944,270 | https://en.wikipedia.org/wiki/Habitability%20of%20neutron%20star%20systems | The habitability of neutron star systems is the potential of planets and moons orbiting a neutron star to provide suitable habitats for life. Of the roughly 3000 neutron stars known, only a handful have sub-stellar companions. The most famous of these are the low-mass planets around the millisecond pulsar PSR B1257+12.
Habitability is conventionally defined by the equilibrium temperature of a planet, which is a function of the amount of incoming radiation; a planet is defined "habitable" if liquid water can exist on its surface although even planets with little external energy can harbour underground life. Pulsars do not emit large quantities of radiation given their small size; the habitable zone can easily end up lying so close to the star that tidal effects destroy the planets. Additionally, it is often unclear how much radiation a given pulsar emits and how much of it can actually reach a hypothetical planet's surface; of the known pulsar planets, only those of PSR B1257+12 are close to the habitable zone and as of 2015, no known pulsar planet is likely to be habitable.
A habitable planet orbiting a neutron star must be between one and 10 times the mass of the Earth. If the planet were lighter, its atmosphere would be lost. Its atmosphere must also be thick enough to convert the intense X-ray radiation from the neutron star into heat on its surface allowing it to have a temperature suitable for life.
A magnetic field strong enough — the magnetosphere — would protect the planet from the strong solar winds. This could preserve the planet's atmosphere for several billion years. Such a planet could have liquid water on its surface.
A Dutch research team published an article on the subject in the journal Astronomy & Astrophysics in December 2017.
See also
Habitability of red dwarf systems
Habitability of K-type main-sequence star systems
Habitability of natural satellites
Neutron stars in fiction
References
Planetary habitability
Neutron stars
Astrobiology | Habitability of neutron star systems | [
"Astronomy",
"Biology"
] | 404 | [
"Origin of life",
"Speculative evolution",
"Astrobiology",
"Biological hypotheses",
"Astronomical sub-disciplines"
] |
71,944,488 | https://en.wikipedia.org/wiki/List%20of%20Art%20Deco%20architecture%20in%20Michigan | This is a list of buildings that are examples of the Art Deco architectural style in Michigan, United States.
Ann Arbor
Burton Memorial Tower, University Of Michigan Central Campus Historic District, Ann Arbor, 1936
First National Bank Building, Ann Arbor, 1927
Nickels Arcade, Ann Arbor, 1915
State Theatre, Ann Arbor, 1942
Battle Creek
Battle Creek Tower, Battle Creek, 1931
Boy's Club Building, Battle Creek, 1928
Heritage Tower, Battle Creek, 1931
Detroit
Argonaut Building (now A. Alfred Taubman Center for Design Education), Detroit, 1928
Albert Kahn Building, Detroit, 1931
Alger Theater, Detroit, 1935
Ambassador Bridge, Detroit to Windsor, Ontario, Canada, 1929
AT&T Michigan Headquarters, Detroit, 1928
Boyce Apartments, Palmer Park Square Apartment Building Historic District, Detroit, 1925 and 1964
Buhl Building, Detroit, 1925
Cass Motor Sales, Detroit, 1928
Crystal Ballroom, Detroit, 1919 and 1936
David Stott Building, Detroit, 1929
Denby High School, Detroit, 1930
Detroit Free Press Building, Detroit, 1925
Detroit Naval Armory, Detroit, 1930
Detroit News Complex, Detroit, 1915
El Tovar Apartments, Detroit, 1928
Elwood Bar, Detroit, 1936
Fisher Building, Detroit, 1928
Fox Theatre, Detroit, 1928
The Frontera Building, Detroit, 1932
Guardian Building, Detroit, 1929
Industrial Building, Detroit, 1928
The Kean, Detroit, 1931
Laredo Apartments, Detroit, 1920s
Lee Plaza, Detroit, 1929
Maccabees Building, Detroit, 1927
Majestic Theater, Detroit, 1915 and 1934
Metropolitan Center for High Technology, Detroit, 1927
Michigan Bell and Western Electric Warehouse, Detroit, 1929
Mumford High School, Detroit, 1949
Music Hall Center for the Performing Arts, Detroit, 1928
Penobscot Building, Detroit, 1928
Pershing High School, Detroit, 1929
Saint Paul Manor Apartments, Detroit, 1925
Stanley's Mania Café, Detroit, 1940
Stratford Theatre, Detroit, 1916 and 1930s
Theodore Levin United States Courthouse, Detroit, 1934
Town Apartments, Detroit, 1929
Vanity Ballroom Building, Detroit, 1929
Whitmore Plaza, Palmer Park Square Apartment Building Historic District, Detroit, 1925 and 1964
William Livingstone Memorial Lighthouse, Belle Isle Park., Detroit, 1929
WWJ (AM) Transmitter Building, Detroit, 1936
Flint
Charles Stewart Mott Foundation Building, Flint, 1928
The Paterson Building, Flint, 1931
Kalamazoo
Kalamazoo Federal Building and U.S. Courthouse, Kalamazoo, 1939
Lake Huron
DeTour Reef Light, Lake Huron, 1931
Martin Reef Light Station, Lake Huron, 1927
Round Island Passage Light, Lake Huron, 1948
Lansing
Boji Tower, Lansing, 1931
Charles E. Chamberlain Federal Building & Post Office, Lansing, 1932
J. W. Sexton High School, Lansing, 1943
J. W. Knapp Company Building, Lansing, 1929
Ottawa Street Power Station, Lansing, 1939
Strand Theatre and Arcade, Lansing, 1920
Saginaw
Michigan Bell Building, Saginaw, 1930
Traverse City
Bijou by the Bay, Traverse City, 1930s
State Theatre, Traverse City, 1923
Other cities
Alpena County Courthouse, Alpena, 1934
B and C Grocery Building, Royal Oak, 1939
Bad Axe Theatre, Bad Axe, 1916
Bay County Building, Bay City, 1933
Berkley Screw Machine Products Factory (now U-Haul & Storage), Rochester, 1946
Cass Theatre, Cass City, 1940
Central Fire Station, Muskegon, 1930
Cranbrook Schools, Bloomfield Hills, 1929
Crystal Theatre, Crystal Falls, 1927
Detroit & Northern Michigan Savings & Loan Association, Quincy Street Historic District, Hancock, 1939
Ford Valve Plant, Northville, 1936
Gladwin County Building, Gladwin, 1939
Gravelly Shoal Light, Saginaw Bay, 1939
Grays Reef Light, Lake Michigan, 1936
Home Repair Services, Grand Rapids,
Howard Miller Clock Company, Zeeland, 1940s
Ionia Theatre, Ionia, 1875 and 1930s
Jenison Fieldhouse, Michigan State University, East Lansing, 1940
John H. Schaefer Building, Dearborn, 1930
Keweenaw Waterway Upper Entrance, Lake Superior, 1937
Landmark Inn, Marquette, 1930
Mackinac County Courthouse, St. Ignace, 1936
Macomb County Building, Mount Clemens, 1933
McKenny Hall, Eastern Michigan University Historic District, Ypsilanti, 1931
McKinley Elementary School, Wyandotte, 1938
Michigan Theatre, Jackson, 1929
Minneapolis Shoal Light Station, Green Bay, Lake Michigan, 1934
Munising Fire Department and Department of Public Works, Munising, 1939
Muskegon YMCA Building, Muskegon, 1926
National Shrine of the Little Flower Basilica, Royal Oak, 1931 and 1936
National Time & Signal Corporation, Oak Park, 1945
Northern Michigan Bank and Trust, Iron Mountain, 1927
Olin Memorial Health Center, East Lansing
Old Regent Theatre, Allegan, 1919 and 1930s
Oldsmobile Dealership (now offices), Grand Rapids
Park Theatre, 108 East Clinton Street, Augusta, 1950
Park Theatre (now Lincoln Park Lofts), Lincoln Park, 1925
The People's State Bank (now Fifth Third Bank), Holland, 1928
Roseville Theatre, 28325 Utica Road, Roseville, 1928
Seaway Painting, 31801 Schoolcraft St, Livonia, 1940s
St. Mary's Academy, St. Mary's Academy Historic District, Monroe, 1931
St. Paul Apostolic Temple Church, 17400 Manderson Road, Highland Park, 1951
State Bank of Perry, Perry, 1913
Temple Israel, West Bloomfield Township, 1949
Trolley Depot Building, Monroe, 1931
Tuscola County Courthouse, Caro, 1933
Twin Lakes Java Coffee Roaster (former Fanny's Tavern), Toivola
Victoria Theater (now Garden Theater), Frankfort, 1923
WJR Radio Transmitter Building, Riverview, 1934
The Westown Theater, 611 Midland Street, Midland Street Commercial District, Bay City, 1915
See also
List of Art Deco architecture
List of Art Deco architecture in the United States
References
"Art Deco & Streamline Moderne Buildings." Roadside Architecture.com. Retrieved 2019-01-03.
Cinema Treasures. Retrieved 2022-09-06
"Court House Lover". Flickr. Retrieved 2022-09-06
"New Deal Map". The Living New Deal. Retrieved 2020-12-25.
"SAH Archipedia". Society of Architectural Historians. Retrieved 2021-11-21.
External links
Art Deco
Lists of buildings and structures in Michigan | List of Art Deco architecture in Michigan | [
"Engineering"
] | 1,300 | [
"Architecture lists",
"Architecture"
] |
71,944,618 | https://en.wikipedia.org/wiki/List%20of%20Art%20Deco%20architecture%20in%20Ohio | This is a list of buildings that are examples of the Art Deco architectural style in Ohio, United States.
Akron
Akron Fulton International Airport Administration Building, Akron, 1930
Akron YMCA Building, Akron, 1931
Civic Theatre, Akron, 1929
Eagles Temple, Akron, 1917
First National Bank Tower, Akron, 1931
Guggenheim Airship Institute, Akron, 1929
Highland Theatre, Akron, 1938
Huntington Tower, Akron, 1931
Linda Theatre, Akron, 1948
North High School, Akron, 1917
Quaker Square, Akron, 1932
Cincinnati
Carew Tower, Cincinnati, 1930
Cincinnati American Building, Cincinnati, 1928
Cincinnati and Suburban Telephone Company Building, Cincinnati, 1931
Cincinnati Enquirer Building, Cincinnati, 1926
Cincinnati Municipal Lunken Airport, Cincinnati, 1925
Cincinnati Times-Star Building, Cincinnati, 1933
Cincinnati Union Terminal, Cincinnati 1933
Coca-Cola Bottling Plant, Cincinnati, 1938
Crosley Building, Cincinnati, 1929
Dalton Street Post Office, Cincinnati, 1932
Dixie Terminal, Cincinnati, 1921
Esquire Theatre, Cincinnati, 1911 and 1939
Ida Street Viaduct, Cincinnati, 1931
John Shillito & Co., Cincinnati, 1878 and 1937
Klosterman Baking Company, Cincinnati, 1880 and 1930s
Main Post Office, Cincinnati, 1920s
Olympic Garage, Cincinnati
Paramount Building (former RKO Paramount Theater), Walnut Hills, Cincinnati, 1928
Potter Stewart United States Courthouse, Cincinnati, 1938
Price Hill Historical Society Museum (former Provident Bank), Price Hill, Cincinnati
Rookwood Ice Cream Parlor, Cincinnati, 1933
S. Gayle and Agnes P. Lowrie House, Cincinnati
Taft Theatre, Cincinnati, 1928
Twentieth Century Theatre, Cincinnati, 1941
Western Hills Viaduct, Western Hills, Cincinnati
Cleveland
AT&T Huron Road Building, Cleveland, 1927
Cleveland Arcade, Cleveland, 1890 and 1939
Cleveland Stadium, Cleveland, 1931
Embassy Theater, Cleveland, 1938
Fenn Tower, Cleveland, 1937
First Catholic Slovak Union, Cleveland
Greyhound Bus Station, Cleveland, 1948
Hope Memorial Bridge, Cleveland, 1932
Landmark Office Towers Complex, Cleveland, 1930
Lerner Building, Cleveland
Ohio Bell Henderson-Endicott Exchange Building, Cleveland, 1928
Ohio Theatre, Cleveland, 1921
Outhwaite Homes, Cleveland, 1935
Sears, Roebuck & Company Building, Cleveland.
Severance Hall, Cleveland, 1931
Shaker Square Cinemas, Cleveland
Terminal Tower, Cleveland, 1930
Tower City Center, Cleveland, 1927
Whiskey Island Coast Guard Station, Whiskey Island, Cleveland, 1940
Columbus
American Education Press Building, 1932
American Education Press Building, 1936
Beggs Building, 1928
Central Assurance Company, 1942
Farm Crest Bakeries Building, 1949
F. W. Woolworth Store, 1937
Jaeger Machine Company Office Building, 1936
Law and Finance Building, 1927
LeVeque Tower, 1927
Lincoln Theatre, 1928
Municipal Light Plant, 1937 and 1950s
Ohio Judicial Center, 1931
Old Port Columbus Airport Terminal and Control Tower, 1929
Palace Theatre, 1927
Royal York Apartments, 1937
Dayton
America's Packard Museum, Dayton, 1917
Dayton Gym Club, Dayton, 1952
Leslie L. Diehl Bandshell, Dayton, 1940
Liberty Tower, Dayton, 1931
White Tower Hamburger, Dayton, 1941
Wympee Burger, Dayton, 1938
Mariemont
Cincinnati Steel Treating Company, Mariemont Historic District, Mariemont 1928
Kellogg's Building, Mariemont Historic District, Mariemont, 1920s–1930s
Packaging Microfactory (former Haney PRC Building), Mariemont Historic District, Mariemont, 1940
Youngstown
Baker's Shoes Building, Youngstown
Burt Building (now Vindicator Building), Youngstown, 1930
Isaly Dairy Plant (now U-Haul), Youngstown, 1930s
Metropolitan Tower, Youngstown, 1929
Peggy Ann Building (now Whistle & Keg), Youngstown, 1930
Powers Auditorium, Youngstown, 1930
S. H. Kress and Co. Building, Youngstown, 1925
Other cities
Ada Theatre, Ada, 1938
Armco Research Building, Middletown, 1937
Apollo Theatre, Oberlin, 1913
Athena Cinema, Athens, 1915 and 1935
Butler Township Hall, Butler Township, 1927
Chase Tower, Mansfield
Cheviot Field House and Community Center, Cheviot, 1936
City Hall, East Liverpool, 1934
Community Building, South Solon, 1938
Donnell Building (Marathon Petroleum Headquarters), Findlay, 1929 and 1941
Drexel Theatre, Bexley, late 1930s
Erie County Courthouse, Sandusky, 1939
Fairborn Theatre, Fairborn, 1948
Fire Department and Municipal Building, Sidney, 1939
Firestone, Toledo, 1920s
Grafton School, Grafton, 1936
Green Township High School, Smithville, 1936 and 1943
The Hangar, Beachwood, 1930
Huron High School, Huron, 1943 and 1952
Italian American Beneficial Club Building, Sandusky, 1941
Kerr Beverage Co., Lorain
Kirby Flowers & Gifts, Portsmouth, 1938
Lake 8 Movies Theatre, Barberton, 1938
Lake Theatre, Barberton, 1938
Mason Municipal Building, Mason
Maumee Indoor Theatre, Maumee, 1946
National City Bank Building, Toledo, 1930
New Cleveland School (now a community center), Ottawa
The Norwalk Theatre, Norwalk (1941)
Ohio Power Company Building, Zanesville, 1929
Police Station, Euclid
Portsmouth City Hall, Portsmouth, 1935
Quaker Cinema, New Philadelphia, 1940
Richland Trust Building, Mansfield, 1929
Silk City Diner#4655, Sabina, 1946
Sparta Grille & Newark Coin Exchange, Newark, 1930s
Springfield Main Post Office, Springfield, 1934
Telephone Building, Newark, 1920s
United States Post Office, Delphos
Vinton County Courthouse, McArthur, 1939
Voice of America Bethany Relay Station, Union Township, 1944
W. T. Grant Building, Steubenville, 1920s
See also
List of Art Deco architecture
List of Art Deco architecture in the United States
References
"Art Deco & Streamline Moderne Buildings." Roadside Architecture.com. Retrieved 2019-01-03.
Cinema Treasures. Retrieved 2022-09-06
"Court House Lover". Flickr. Retrieved 2022-09-06
"New Deal Map". The Living New Deal. Retrieved 2020-12-25.
"SAH Archipedia". Society of Architectural Historians. Retrieved 2021-11-21.
External links
Art Deco
Lists of buildings and structures in Ohio | List of Art Deco architecture in Ohio | [
"Engineering"
] | 1,227 | [
"Architecture lists",
"Architecture"
] |
71,944,757 | https://en.wikipedia.org/wiki/List%20of%20Art%20Deco%20architecture%20in%20Texas | This is a list of buildings that are examples of the Art Deco architectural style in Texas, United States.
Amarillo
2500 South Van Buren Street, Amarillo, 1935
2200 South Ong Street, Amarillo, 1936
The Derrick Building (former Greyhound Depot), Amarillo, 1949
Eddie's Napoli's Italian Restaurant, Amarillo, 1930s
Esquire Jazz Club (former Esquire Theatre), Amarillo, 1947
J. Marvin Jones Federal Building and United States Courthouse, Amarillo, 1939
Kress Center City, Amarillo, 1932
Levine's Department Store, Amarillo, 1936
Louis H. Smith, Inc. Firestone Store, Amarillo, 1930
Paramount Theater Building, Amarillo, 1932
Potter County Courthouse, Amarillo, 1932
Triangle Motel, Amarillo, 1946
White and Kirk Department Store (now Amarillo National Bank), Amarillo, 1938
Austin
3805 Red River Street, Austin, 1947
Austin Central Fire Station 1, Austin, 1938
Austin Daily Tribune Building, Austin, 1941
Brown Building, Austin, 1938
Dewitt C. Greer State Highway Building, Austin, 1933
Scarbrough Building, Austin, 1909 and 1931
Seaholm Power Plant, Austin, 1928
State Theater, Austin, 1935
Texas Memorial Museum, Austin, 1936–1939
Travis County Courthouse, Austin, 1931
United States Courthouse, Austin, 1936
Baytown
First National Bank of Goose Creek, Baytown, 1948
Odd Fellows Hall, Baytown, 1929
St. Joseph Catholic Church, Baytown, 1958
Beaumont
First National Bank Building, Beaumont, 1937
Jack Brooks Federal Building, Beaumont, 1933
Jefferson County Courthouse, Beaumont, 1931
Kyle Building, Beaumont, 1931
Bryan
Bryan Municipal Building, Bryan, 1929
First State Bank & Trust, Bryan, 1929
Old Sinclair Station, Bryan, 1933
Dallas
508 Park Avenue, Dallas, 1929
6851 Gaston Avenue, Dallas, 1936
Bath House Cultural Center, Dallas, 1930
Cotton Bowl Stadium, Dallas, 1936
Dallas High School Arts and Sciences Building, Dallas, 1930 and 1941
Dallas High School Classics Building, Dallas, 1930, 1941
Dallas Power & Light Building, Dallas, 1931
Fair Park Station, Dallas, 1936
Hall of State, Dallas, 1936
John E. Mitchell Company Plant, Dallas, 1928
Margaret B. Henderson Elementary School, Dallas, 1941
Medical Dental Building, Dallas, 1928
Mercantile National Bank Building, Dallas, 1942
Texas Theatre, Dallas, 1931
Tower Petroleum Building, Dallas, 1931
The Women's Museum, Dallas, 1936
El Paso
Coldwell Elementary School, El Paso, 1930
Fire Station 11, 331 South Santa Fe, El Paso, 1930
O. T. Bassett Tower, El Paso, 1930
Pershing Theater (now artist's studio), El Paso, 1940
Plaza Hotel, El Paso, 1929
S. H. Kress and Co. Building, El Paso, 1938
State Theater, 108 E. San Antonio, El Paso, 1914
United States Court House, El Paso, 1936
Valley Theater, (former Cine Azteca), El Paso, 1948
Fort Worth
American Airways Hangar and Administration Building, Fort Worth, 1933
Ashton Hotel, Fort Worth, 1915
Barber's Bookstore, Fort Worth, 1910, 1935
Blackstone Hotel, Fort Worth, 1929
Central Fire Station No. 2, Fort Worth, 1930
Commerce Building, Fort Worth, 1930
Farrington Field, Fort Worth, 1939
Fort Worth Masonic Temple, Fort Worth, 1932
Lone Star Gas Company Building, Fort Worth, 1929
Palace Theater Block, Fort Worth, 1996
Public Safety and Courts Building, Fort Worth, 1938
S. H. Kress and Co. Building, Fort Worth, 1936
Santa Fe Freight Station, Fort Worth, 1938
Sinclair Building, Fort Worth, 1930
Stockyards Movie House, Fort Worth, 1930s
T&P Station, Fort Worth, 1930
W. T. Grant Department Store, Fort Worth, 193
Western Union Building, Fort Worth, 1931
Will Rogers Memorial Center, Fort Worth, 1936
Galveston
Alamo Elementary School (now storage), Galveston, 1935
Elks Lodge, Galveston, 1940s
Galveston Railroad Museum (former Santa Fe Building), Galveston, 1932
Galveston United States Post Office and Courthouse, Galveston, 1937
Graugnard's Bakery Building, Galveston, 1940
Medical Arts Building, Galveston, 1929
Houston
1940 Air Terminal Museum, Houston, 1940
333 20th Street Building, Houston, 1952
Alabama Theatre, Houston, 1939
Albritton's Eats, Houston, 1945
Almeda Court Apartments, Houston, 1939
Bellaire Theatre, West University Place, Houston, 1949
Brochsteins Inc, Houston, 1940, 1947
Byrd's Department Store, Houston, 1934
Cameron Iron Works, Houston, 1935
City National Bank Building, Houston, 1947
Clarke & Courts Building (now Tribeca Lofts), Houston, 1936
Cullen Performance Hall, Houston, 1950
Dahlgren's Cabinet Shop, Houston, 1940
Elias Ramirez State Office Building (former Hughes Tool Company, Inc.), Houston, 1942
Ezekiel W. Cullen Building, University of Houston, Houston, 1946–1950
Fondren Library, Rice University, Houston, 1946
Friendswood Junior High, Friendswood, 1939, 1949
Gonzales Memorial Museum and Amphitheater, Gonzales, 1937
Great Southwest Building, Houston, 1927
Gribble Stamp & Stencil Co., Houston, 1948
Gulf Building/JP Morgan Chase Building, Houston, 1929
Hamman Exploration Co., Houston, 1940
Harris County Peden Community Correction Facility, Houston, 1929
Heights Theater, Houston, 1929
Houston City Hall, Houston, 1938–39
Houston Metropolitan Dance Center, Houston, 1941
Houston National Cemetery, Houston, 1965
James Coney Island No. 26, Houston, 1992
JPMorgan Chase Building (former Levy Dry Goods), Houston, 1929
L. D. Allen Residence, Houston, 1937
Lamar High School, Houston, 1936
Lamar-River Oaks Shopping Center, Houston, 1948
Lawndale Art Center, Houston, 1931
Lucian L. Lockhart Elementary School (former Congregation Beth Yeshurun Educational Building), Houston, 1949
Mellie Esperson Building, Houston, 1941
Merchants and Manufacturers Building, Houston, 1930
Montrose Townhouse Lofts, Houston, 1997
Oak Farms Dairy (now Dean Foods), Houston, 1937
Reserve 101 Bar, Houston, 1935
River Oaks Theatre, Houston, 1939
Roy and Lillie Cullen Building, Baylor College of Medicine, Houston, 1948
Roy G. Cullen Building, University of Houston, Houston, 1938–39
Stephen F. Austin High School, Houston, 1936
Temple of Rest, Congregation Beth Israel, Houston, 1935
Williams Tower, Houston, 1982
Weingarten's Big Food Market (now West End Shopping Center), Houston, 1941
Lubbock
Cactus Theater, Lubbock, 1938
Carlock Building, Lubbock, 1930
Lubbock County Jail, Lubbock, 1931
San Angelo
Masonic Lodge 570, San Angelo, 1931
Princess Ice Cream Co., San Angelo, 1931
San Angelo City Hall, San Angelo, 1928
Texas Theatre, San Angelo, 1929
San Antonio
Alamo Stadium, San Antonio, 1940
Freeman Coliseum, San Antonio, 1949
George Washington Carver Library and Auditorium, San Antonio, 1930
Lerma's Nite Club, San Antonio, 1948
Martha Roberson Hall, San Antonio, 1939
San Antonio Express-News Building, San Antonio, 1930
Taylor
City Hall, Taylor, 1935
Howard Theater, Taylor, 1914
Taylor High School Campus, Taylor, 1923
Taylor Motor Company, Taylor, 1931
Tyler
Blackstone Building, Tyler, 1938
Jenkins-Harvey Super Service Station and Garage, Tyler, 1929
Liberty Hall, Tyler, 1930
Other cities
431 North Main Street, Borger
3M Palace Theater, Colorado City
Andrews County Courthouse, Andrews, 1939
Beltonian Theatre, Belton, 1900
Blue Bell Creameries Complex, Brenham, 1911 and 1935
Brauntex Theatre, New Braunfels, 1942
Brazoria County Courthouse, Angleton, 1941
Brownlee Diner/Little Juarez Cafe, Glenrio, 1952
Brunson Theater, Baytown, 1949
Burnet County Courthouse, Burnet, 1937
Butter Krust Bakery, Corpus Christi, 1938
Celina High School, Celina, 1941
Chambers County Courthouse, Anahuac, 1937
Childress County Courthouse, Childress Commercial and Civic Historic District, Childress, 1939
Cine El Rey, McAllen, 1947
Clear View High School, Webster, 1939
Combs–Worley Building, Pampa, 1931
Corrigan Center (now Harris Health System), Pasadena, 1956
Corstone Sales Company, Lufkin, 1935
Cottle County Courthouse, Cottle County Courthouse Historic District, Paducah, 1930
Crim Theatre, Kilgore, 1938
Delta County Courthouse, Cooper, 1941
Edna Theatre, Edna, 1950
Esquire Theater, Carthage, 1949
Fannin County Courthouse, Bonham, 1889
Federal Building, Abilene, 1936
Fine Arts Theatre (former Texas Theatre), Denton, 1935
Galvan Ballroom, Corpus Christi, 1950
Garmon Theatre, Rio Grande City, 1940s
Graham Post Office, Graham, 1935–1939
Gregg County Courthouse, Longview, 1932
Hachar's Department Store, Laredo, 1942
Hall Furniture Building, Sherman, 1936
Hamilton County Jail (now Hamilton County Historical Museum), Hamilton, 1938
Hansford County Courthouse, Spearman, 1931
Higginbotham–Bartlett Co., Post, 1940s
Hollingsworth Ford Auto Showroom, Harlingen, 1930
Hotel Faust, New Braunfels, 1929
Hotel McCartney, Texarkana, 1929
Hotel Marshall, Marshall, 1929
Houston County Courthouse, Crockett, 1938
J. P. Lenoir Elementary, Donna, 1925
Jacksonville Post Office, Jacksonville, 1933
La Salle County Courthouse, Cotulla, 1931
Lan-Tex Theatre, Llano, 1927
Lance Theatre, Rotan
Liberty County Courthouse, Liberty, 1931
Loving County Courthouse, Mentone, 1935
Masonic Lodge, Grandfalls, 1930s or 1940s
Maverick County Jail, Eagle Pass, 1949
Menard County Courthouse, Menard, 1931
Morley Theatre, Borger, 1947
National Theater, Graham, 1941
Nocona Athletic Goods Company, Nocona, 1925
Orange County Courthouse, Orange, 1937
Palace Theater, Childress Commercial and Civic Historic District, Childress, 1937
Palace Theatre (former Marfa Opera House), Marfa
Palace Theater, Seguin, 1938
Paris Community Theatre (former Palace Theatre), Paris, 1926
Pearland School (now Alvin Community College – Pearland Campus), Pearland, 1945
People's National Bank Building, Tyler, 1932
Phipps Memorial, Waco, 1939
Pines Theater, Lufkin, 1925
Plainview Hardware Company Building, Perryton, 1930
Plaza Arts Center, Carrollton, 1949
Plaza Theatre, Garland, 1941
Plaza Theatre, Laredo, 1946
Randolph Air Force Base Administration Building, Universal City, 1931
Refugio County Courthouse, Refugio, 1917 and 1951
Rialto Theater, Alice, 1940
Rialto Theater, Beeville, 1936
Rialto Theater, Three Rivers, 1948
Rig Theater, Wink, 1928
Rio Grande Telephone Company, Brownsville, 1931
San Jacinto Monument, Harris County, 1939
Settles Hotel, Big Spring, 1930
South County Office Building, Port Arthur, 1936
Tarver Abstract Company Building (former First National Bank), Liberty, 1932
Texas State Bank, Alice, 1912 and 1940
Texaco Station, Glenrio, 1950
Texas Theater, Ballinger, 1928
Texas Theatre, McGregor, 1912
Texas Theatre, Waxahachie, 1914 and 1927
Tower Theatre, Lamesa, 1930s
U-Drop Inn, Shamrock, 1936
United States Post Office - Pampa Main, Pampa, 1934
Universal Manufacturing Company Building, Abilene, 1927
Upshur County Courthouse, Gilmer, 1937
Uptown Theatre, Grand Prairie, 1950
Van Zandt County Courthouse, Canton, 1937
Vernon Plaza Theatre, Vernon, 1953
W. R. Banks Library, Prairie View, 1946
Waggoner Ranch, Vernon, 1923
Washington County Courthouse, Brenham, 1939
See also
List of Art Deco architecture
List of Art Deco architecture in the United States
References
"Art Deco & Streamline Moderne Buildings." Roadside Architecture.com. Retrieved 2019-01-03.
Cinema Treasures. Retrieved 2022-09-06
"Court House Lover". Flickr. Retrieved 2022-09-06
Highland, Brittany. "Inherit Austin Tours Historic Downtown Deco Worth Keeping". The Austinot. 2012-09-25. Retrieved 2019-01-17.
"Houston Deco". Preservation Houston. Retrieved 2019-01-17.
"New Deal Map". The Living New Deal. Retrieved 2020-12-25.
"SAH Archipedia". Society of Architectural Historians. Retrieved 2021-11-21.
"Walking Tour of Downtown Fort Worth." Fort Worth Architecture. Retrieved 2022-09-06\
External links
Art Deco
Lists of buildings and structures in Texas | List of Art Deco architecture in Texas | [
"Engineering"
] | 2,570 | [
"Architecture lists",
"Architecture"
] |
71,944,978 | https://en.wikipedia.org/wiki/International%20Journal%20of%20Fatigue | The International Journal of Fatigue is a monthly peer-reviewed scientific journal covering research, theory, and practice concerning the fatigue of materials and structures. The journal is published by Elsevier in affiliation with the European Structural Integrity Society. As of October 2022, the editors-in-chief are Guozheng Kang (Southwest Jiaotong University), Michael D. Sangid (Purdue University), and Michael Vormwald (TU Darmstadt).
Abstracting and indexing
The journal is abstracted and indexed in:
According to the Journal Citation Reports, the journal has a 2022 impact factor of 6.0.
See also
Fracture mechanics
Solid mechanics
References
External links
Materials science journals
Elsevier academic journals
Monthly journals
English-language journals
Academic journals established in 1979 | International Journal of Fatigue | [
"Materials_science",
"Engineering"
] | 152 | [
"Materials science journals",
"Materials science"
] |
71,946,127 | https://en.wikipedia.org/wiki/Ellen%20Moons | Ellen Moons is a Belgian materials scientist who is a professor at Karlstad University. Her research considers the organisation of molecules and materials in thin films. She is mainly interested in organic and hybrid materials for solution processed photovoltaics.
Early life and education
Moons is from Belgium. As an undergraduate, she studied physics at Ghent University. After finishing her MSc studies, she was awarded a scholarship by the Israeli Foreign Ministry, and spent half a year in Israel. She decided to stay for doctoral studies, and worked at the Weizmann Institute of Science alongside David Cahen. Her doctoral research considered photovoltaic cells based on cadmium telluride. These photovoltaics have lower costs than silicon based devices, and have a small carbon footprint. Moons was a postdoctoral researcher at École Polytechnique Fédérale de Lausanne and at the Delft University of Technology. Her research considered dye-sensitised solar cells.
Moons worked as a research scientist at Cambridge Display Technology, where she worked on polymer light-emitting diodes. During this time she held a joint position with the University of Cambridge, and worked alongside Richard Friend.
Research and career
Moons joined Karlstad University in 2011. That year she was awarded the Göran Gustafsson Prize. At the time, Karlstad primarily focussed on polymer-based photovoltaics. Moons expanded this research area, introducing new materials and investigations into structure-property relationships. Moons works to understand degradation mechanisms within emerging energy materials in an effort to improve device performance, stability and lifetime.
Moons' group have helped to correlate solar cell morphology with performance. In particular, she helped to explain how the donor and acceptor domains that form within the active layers of solar cells during solution processing impact their performance. Her work on morphology was supported by the K. A. Wallenberg foundation. Alongside the morphology of the active layer, she has studied how the device energetics (e.g. energy levels of the interlayers and interfaces) impact device performance.
Moons has made use of atomic force microscopy to understand nanoscale features on the surface of her thin films. To interrogate the chemical composition of these domains, Moons has shown it is possible to combine atomic force microscopy with infrared spectroscopy. To probe the bulk structure of the thin films, Moons uses dynamic secondary ion mass spectrometry.
In 2018, Moons was elected to the Royal Swedish Academy of Sciences. She was one of five women in a class of fifty five, and the first member from Karlstad University to be elected. She said she would use the position to advance the role of physics in society. As part of this role, she served on the Nobel Committee for Physics and delivered a YouTube lesson describing the science that won the 2018 Nobel Prize in Physics.
Selected publications
References
Living people
Weizmann Institute of Science alumni
Karlstad University alumni
Materials scientists and engineers
Belgian women scientists
Year of birth missing (living people) | Ellen Moons | [
"Materials_science",
"Engineering"
] | 592 | [
"Materials scientists and engineers",
"Materials science"
] |
71,946,723 | https://en.wikipedia.org/wiki/Metal%E2%80%93organic%20biohybrid | Metal–organic biohybrids (MOBs) are a family of materials containing a metal component, such as copper, and a biological component, such as the amino acid dimer cystine. One of the MOB families first described was the copper-high aspect ratio structure called CuHARS. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of CuHARS revealed linear morphology and smooth surface texture. SEM, TEM and light microscopy showed that CuHARS composites had scalable dimensions from nano- to micro-, with diameters as low as 40 nm, lengths exceeding 150 microns, and average aspect ratios of 100.
Structure
MOBs are composed of two major components: a metal ion or cluster of metal ions and a biological molecule. Examples are:
CuHARS which contain copper as the metal ion and cystine as the biological molecule
The use of silver as the metal ion in combination with cystine. Cystine is the dimer form of the amino acid cysteine. Cobalt has also been used in combination with cystine to form CoMOBs.
When combined with copper to form CuHARS, the cystine may provide a linker function leading to a linear, high-aspect ratio structure that gives CuHARS its name: copper high-aspect ratio structures. In contrast to CuHARS, MOBs formed with silver and cystine result in silver nanoparticles with spherical, rounded structure. These have been named AgCysNPs.
Figure 1 shows comparative electron microscopy of CuHARS and AgCysNPs.
Synthesis
MOBs under reducing conditions using sodium hydroxide (NaOH) can be self-assembled at body temperature (37 degrees Celsius). In the case of copper CuHARS, MOBs can be produced by transforming copper nanoparticles to provide the copper source, or using copper(II) sulfate.
Physical Characteristics
CuHARS have been shown to completely degrade under physiological conditions (cell culture media at 37 °C), even in the absence of cells; this is possibly due to the metal chelating properties of typical cell culture medias. These may include the copper-binding properties of cerulosplasmin and of albumin. Additionally, CuHARS have been shown to polarize light using inverted microscopy. Cobalt-containing MOBs (CoMOBs) have been shown to be susceptible to an externally applied magnetic field as shown in Figure 2.
Uses and Applications
MOBs have been incorporated into composites including cellulose. Additionally, MOBs composed of the copper-containing CuHARS have been shown to provide catalytic function to produce nitric oxide (NO).
Nitric Oxide production
This production of NO was shown to impart anti-microbial activity, and the CuHARS in this case were incorporated into a biodegradable, biocompatible, and renewable resource material, namely cellulose. The release of NO catalzyed by copper from CuHARS may have beneficial biomedical applications.
Anti-Cancer Effects
Both copper- and silver-containing MOBs were shown to have anti-cancer effect on cells in vitro. In the case of possible uses for CuHARS, copper may have a potential role in tumor immunity and for antitumor therapy. Since CuHARS are 100% biodegradable under physiological conditions, copper metabolism of CuHARS may have benefits as an approach for treating glioma.
MOBs as Green Materials using Self-Assembly
Green nanomedicine has been suggested as a path to the next generation of materials for diagnosing brain tumors and for therapeutics, including the use of CuHARS.
Angiogenic Effects
CuHARS embedded into nanofiber aerogels have been shown to have angiogenic effects.
Antibacterial Effects
CuHARS embedded into nanofiber aerogels and via CuHARS-mediated nitric oxide generation have both been examples of antibacterial effects.
References
Biomaterials
Metals
Copper compounds
Silver compounds
Nanoparticles
Cobalt compounds | Metal–organic biohybrid | [
"Physics",
"Chemistry",
"Biology"
] | 832 | [
"Biomaterials",
"Metals",
"Materials",
"Matter",
"Medical technology"
] |
71,947,732 | https://en.wikipedia.org/wiki/Quaterpyridine | Quaterpyridine refers to a family of pyridine derivatives with the formula (NC5H4-C5H3N)2. These compounds can also be viewed as bipyridine decorated with two pyridyl substituents. Several isomers are known. All are colorless solids. One particular isomer, 2,2':6',2'':6'',2'''-quaterpyridine, a derivative of 2,2'-bipyridine has attracted interest because it is a potential tetradentate ligand in coordination chemistry.
Related compounds
terpyridine
References
Chelating agents
Pyridines
Bipyridines | Quaterpyridine | [
"Chemistry"
] | 148 | [
"Chelating agents",
"Process chemicals"
] |
71,950,001 | https://en.wikipedia.org/wiki/Chen%20Wen-chang | Chen Wen-chang (; born 1963) is a Taiwanese chemical engineer and academic administrator who is the current president of the National Taiwan University. Succeeding Kuan Chung-ming, he took his position as president of the university on 8 January 2023.
Education
Chen graduated from National Taiwan University (NTU) in 1985 with a bachelor's degree in chemical engineering and completed a Ph.D. in the same subject at the University of Rochester in 1993.
Career
Chen returned to teach in Taiwan as a professor at NTU and later became dean of the College of Engineering. In 2021, he was awarded a National Chair Professorship in engineering and applied science. Chen was one of nine candidates certified by NTU's Presidential Election Committee in July 2022 to contest the office. A subsequent vote reduced the number of candidates to six, and Chen won another round of voting in October 2022.
References
Taiwanese chemical engineers
Taiwanese university and college faculty deans
20th-century Taiwanese engineers
1963 births
Taiwanese expatriates in the United States
Living people
21st-century Taiwanese engineers
Academic staff of the National Taiwan University
Presidents of National Taiwan University
University of Rochester alumni
Chemical engineering academics | Chen Wen-chang | [
"Chemistry"
] | 232 | [
"Chemical engineering academics",
"Chemical engineers"
] |
71,950,807 | https://en.wikipedia.org/wiki/L%27Aquila%20saffron | L'Aquila saffron () is a saffron product of cuisine of Abruzzo, Italy. It is traditionally cultivated in Navelli plateau and in Subequana Valley, in the Park Municipalities of Fagnano Alto, Fontecchio, Molina Aterno, Tione degli Abruzzi. Saffron was introduced in Italy from Spain in 13th century by a friar Dominican belonging to the Santucci family of Navelli. The production in the Navelli Plain is favored by the karst of the soil, which avoids the stagnation of water which is unfavorable to the growth of the plant.
Under its Italian name "Zafferano dell'Aquila" the product is registered as a Protected Designation of Origin since February 4, 2005, while the establishment of the Consortium for the Protection of Zafferano dell'Aquila dates back to May 13, 2005. The name may only be used if it is produced according its specifications within the municipalities Barisciano, Caporciano, Fagnano Alto, Fontecchio, L'Aquila, Molina Aterno, Navelli, Poggio Picenze, Prata d'Ansidonia, San Demetrio nei Vestini, S. Pio delle Camere, Tione degli Abruzzi or Villa S. Angelo at an altitude of 350 -1000 metres above sea level.. It is included in the Slow Food movement Ark of Taste, an international catalogue of endangered heritage foods.
Production
The soil is prepared in spring with a 'plowing at a depth of 30 cm, with the simultaneous fertilization through about 30 t / ha of manure, being then prohibited the use of any fertilizer during the vegetative cycle. The surface is subsequently refined and leveled and 2 or 4 grooves are prepared at a distance of about 20 cm to accommodate the bulbs.
After a subsequent Milling of the soil, in August the bulbs are transplanted, with a density of about 10 t / ha, corresponding to about 600 000 bulbs. The soil is not irrigated and the bulbs are buried on the row in contact and at a depth of about 10 cm.
The first leaves filiform sprout with the first rains of September, with a development up to 40 cm. The flowers have six petals of a pinkish-purple color, with three scarlet red filaments representing the female part and three yellow anthers representing the male part.
The flowers are harvested around the second fortnight of October before they hatch at dawn. At their withering once they are brought indoors, the stigmas are removed which, placed on a sieve, are placed on the embers of wood of almond or oak for the toasting.
After roasting, the weight of the stigmas is reduced to one sixth of the initial weight, with 5–10% residual moisture, and from these the powder is prepared by grinding. The production of one kilogram of saffron requires about 200,000 flowers.
Culinary use
Saffron in Abruzzo cuisine is used above all for fish dishes such as scapece alla vastese and saffron mussels; moreover in the region it is also used to produce the liqueur Liquore allo zafferano.
L'Aquila saffron in culture
One legend wants the introduction of saffron due to Pontius Pilate whose residence in villas in the area would be testified by as many legends and actual archaeological finds.
Philately
In 2008, an Italian stamp, polychrome and serrated, worth €0.60, was issued featuring L'Aquila saffron and its PDO classification.
Cinema
Aquila saffron is mentioned in animated film Ratatouille (2007) by Pixar; in the scene, present both in the original English language edition (as L'Aquila saffron), in French (as Safran de l'Aquilà) and in Italian, where the product is characterized as "excellent".
See also
Cuisine of Abruzzo
References
Cuisine of Abruzzo
Abruzzo
Italian products with protected designation of origin
Saffron
Saffron
Food colorings
Incense material | L'Aquila saffron | [
"Physics"
] | 867 | [
"Incense material",
"Materials",
"Matter"
] |
71,951,065 | https://en.wikipedia.org/wiki/GalNAc-T%20activation%20pathway | The GalNAc-T activation (GALA) pathway is a cellular process in which GalNAc-T enzymes, involved in O-linked glycosylation, are relocated from the Golgi to the ER. Activation of the pathway is thought to result in the alteration of the glycosylation status of a number of GalNAc-T substrates. This pathway was shown to be highly activated in cancer cells and was proposed as an explanation of the noticeable increased expression of Tn antigen seen in tumours.
Mechanism
The retrograde transport of GalNAc-Ts from the Golgi to the ER is believed to result from the activation of the proto-oncogene tyrosine-protein kinase Src present on the Golgi membrane. This was demonstrated through stimulation of HeLa cells with either EGF or PDGF. Activation of Src triggers the phosphorylation of the GTP exchange factor (GEF) GBF1 hence promoting an interaction between GBF1 and the small GTPase Arf1. Ultimately those Src induced molecular events have been associated with the formation of COPI dependent transport carriers containing GalNAc-Ts and allowing their transport from the Golgi to the ER.
Clinical significance
Activation of the GALA pathway has been tightly associated with ECM degradation. Study of the changes in glycosylation of the GalNAc-T substrate Calnexin-ERp57 has revealed a novel ECM degradative function for this oxidoreductase complex. In fact, GALA activation results in changes in the glycosylation status of Calnexin leading to its relocalization to the cell surface and ultimately promoting this ECM degradation. GALA being highly activated in some cancer cells, Calnexin is logically a promising targetable tumour antigen. In addition, MMP14 is another GalNAc-T substrate for which GALA induced glycosylation changes impact the ECM degradation process.
History
The retro-translocation of GalNAc-Ts from the Golgi to the endoplasmic reticulum was first observed in 2010 by Bard et al. The term GALA was then first used in 2016 by Bard & Chia to designate this molecular pathway. In 2017 the GALA pathway was subject to skepticism from the scientific community due to the inability of Tabak et al. to observe, as previously reported, the relocation of GalNAc-Ts and Tn antigens in HeLa cells upon EGF or PDGF stimulation. However, results supporting the GALA pathway were subsequently re-obtained and critical review of the procedures that failed to support the pathway faded remaining reluctances for the model.
References
Protein targeting | GalNAc-T activation pathway | [
"Biology"
] | 546 | [
"Protein targeting",
"Cellular processes"
] |
71,951,572 | https://en.wikipedia.org/wiki/T-1152 | T-1152 is a quaternary carbamate anticholinesterase. It is synthesized by reaction of m-dimethylaminophenol with methyl isocyanate, followed by quaternization with methyl iodide. Since T-1152 is toxic by ingestion, it was patented as a rodenticide in 1932.
The chloride and methylsulfate salt of T-1152 is T-1690 (TL-1226) and AR-13, respectively.
See also
Neostigmine
T-1123
T-1194
TL-599
TL-1238
References
Carbamate nerve agents
Acetylcholinesterase inhibitors
Aromatic carbamates
Phenol esters
Quaternary ammonium compounds
Iodides
Rodenticides | T-1152 | [
"Biology"
] | 167 | [
"Biocides",
"Rodenticides"
] |
76,276,994 | https://en.wikipedia.org/wiki/Security%20and%20privacy%20of%20iOS | The iOS operating system utilizes many security features in both hardware and software, from the boot process to biometrics.
Secure Boot
Before fully booting into iOS, there is low-level code that runs from the Boot ROM. Its task is to verify that the Low-Level Bootloader is signed by the Apple Root CA public key before running it. This process is to ensure that no malicious or otherwise unauthorized software can be run on an iOS device. After the Low-Level Bootloader finishes its tasks, it runs the higher level bootloader, known as iBoot. If all goes well, iBoot will then proceed to load the iOS kernel as well as the rest of the operating system.
Secure Enclave
The Secure Enclave is a coprocessor found in iOS devices part of the A7 and newer chips used for data protection. It includes the user data pertaining to Touch ID, Face ID, and Apple Pay, among other sensitive data. The purpose of the Secure Enclave is to handle keys and other info such as biometrics that is sensitive enough to not be handled by the Application Processor (AP). It is isolated with a hardware filter so the AP cannot access it. It shares RAM with the AP, but its portion of the RAM (known as TZ0) is encrypted. The secure enclave itself is a flashable 4 MB AKF processor core called the secure enclave processor (SEP) as documented in Apple Patent Application 20130308838. The technology used is similar to ARM's TrustZone/SecurCore but contains proprietary code for Apple KF cores in general and SEP specifically. It is also responsible for generating the UID key on A9 or newer chips that protects user data at rest.
It has its own secure boot process to ensure that it is completely secure. A hardware random number generator is also included as a part of this coprocessor. Each device's Secure Enclave has a unique ID that is fused into the SoC at manufacturing time and cannot be changed. Starting with A9 devices, the unique ID is generated by the Secure Enclave's random number generator and is never exposed outside of the device. This identifier is used to create a temporary key that encrypts the memory in this portion of the system. The Secure Enclave also contains an anti-replay counter to prevent brute force attacks.
The SEP is located in the devicetree under IODeviceTree:/arm-io/sep and managed by the AppleSEPManager driver.
In 2020, security flaws in the SEP were discovered, causing concerns about Apple devices such as iPhones.
Face ID
Face ID is a face scanner that is embedded in the notch on iPhone models X, XS, XS Max, XR, 11, 11 Pro, 11 Pro Max, 12, 12 Mini, 12 Pro, 12 Pro Max, 13, 13 Mini, 13 Pro, 13 Pro Max, 14, and the 14 Plus. On the iPhone 14 Pro, 14 Pro Max, iPhone 15, iPhone 15 Plus, iPhone 15 Pro, and iPhone 15 Pro Max, it is embedded in the Dynamic Island. It can be used to unlock the device, make purchases, and log into applications among other functions. When used, Face ID only temporarily stores the face data in encrypted memory in the Secure Enclave, as described above. There is no way for the device's main processor or any other part of the system to access the raw data that is obtained from the Face ID sensor.
Passcode
iOS devices can have a passcode that is used to unlock the device, make changes to system settings, and encrypt the device's contents. Until recently, these were typically four numerical digits long. However, since unlocking the devices with a fingerprint by using Touch ID has become more widespread, six-digit passcodes are now the default on iOS with the option to switch back to four or use an alphanumeric passcode.
Touch ID
Touch ID is a fingerprint scanner that is embedded in the home button and can be used to unlock the device, make purchases, and log into applications among other functions. When used, Touch ID only temporarily stores the fingerprint data in encrypted memory in the Secure Enclave, as described above. Like Face ID, there is no way for the device's main processor or any other part of the system to access the raw fingerprint data that is obtained from the Touch ID sensor.
Address Space Layout Randomization
Address Space Layout Randomization (ASLR) is a low-level technique of preventing memory corruption attacks such as buffer overflows. It involves placing data in randomly selected locations in memory in order to make it more difficult to predict ways to corrupt the system and create exploits. ASLR makes app bugs more likely to crash the app than to silently overwrite memory, regardless of whether the behavior is accidental or malicious.
Non-executable memory
iOS utilizes the ARM architecture's Execute Never (XN) feature. This allows some portions of the memory to be marked as non-executable, working alongside ASLR to prevent buffer overflow attacks including return-to-libc attacks.
Encryption
As mentioned above, one use of encryption in iOS is in the memory of the Secure Enclave. When a passcode is utilized on an iOS device, the contents of the device are encrypted. This is done by using a hardware AES 256 implementation that is very efficient because it is placed directly between the flash storage and RAM.
iOS, in combination with its specific hardware, uses crypto-shredding when erasing all content and settings by obliterating all the keys in 'effaceable storage'. This renders all user data on the device cryptographically inaccessible.
Keychain
The iOS keychain is a database of login information that can be shared across apps written by the same person or organization. This service is often used for storing passwords for web applications.
App security
Third-party applications such as those distributed through the App Store must be code signed with an Apple-issued certificate. In principle, this continues the chain of trust all the way from the Secure Boot process as mentioned above to the actions of the applications installed on the device by users. Applications are also sandboxed, meaning that they can only modify the data within their individual home directory unless explicitly given permission to do otherwise. For example, they cannot access data owned by other user-installed applications on the device. There is a very extensive set of privacy controls contained within iOS with options to control apps' ability to access a wide variety of permissions such as the camera, contacts, background app refresh, cellular data, and access to other data and services. Most of the code in iOS, including third-party applications, runs as the "mobile" user which does not have root privileges. This ensures that system files and other iOS system resources remain hidden and inaccessible to user-installed applications.
App Store bypasses
Companies can apply to Apple for enterprise developer certificates. These can be used to sign apps such that iOS will install them directly (sometimes called "sideloading"), without the app needing to be distributed via the App Store. The terms under which they are granted make clear that they are only to be used for companies who wish to distribute apps directly to their employees.
Circa January–February 2019, it emerged that a number of software developers were misusing enterprise developer certificates to distribute software directly to non-employees, thereby bypassing the App Store. Facebook was found to be abusing an Apple enterprise developer certificate to distribute an application to underage users that would give Facebook access to all private data on their devices. Google was abusing an Apple enterprise developer certificate to distribute an app to adults to collect data from their devices, including unencrypted data belonging to third parties. Certificates are also used by services such as AltStore, AppValley, Panda Helper, TweakBox and TutuApp to distribute apps that offer pirated software.
Network security
iOS supports TLS with both low- and high-level APIs for developers. By default, the App Transport Security (ATS) framework requires that servers use at least TLS 1.2. However, developers are free to override this framework and utilize their own methods of communicating over networks. When Wi-Fi is enabled, iOS uses a randomized MAC address so that devices cannot be tracked by anyone sniffing wireless traffic.
Two-factor authentication
Two-factor authentication is an option in iOS to ensure that even if an unauthorized person knows an Apple ID and password combination, they cannot gain access to the account. It works by requiring not only the Apple ID and password, but also a verification code that is sent to an iDevice or mobile phone number that is already known to be trusted. If an unauthorized user attempts to sign in using another user's Apple ID, the owner of the Apple ID receives a notification that allows them to deny access to the unrecognized device.
Hardened memory allocation
iOS features a hardened memory allocator known as kalloc_type that was introduced in iOS 15. Since the XNU kernel is primarily written in memory unsafe languages such as C and C++, kalloc_type is designed to mitigate the large amount of vulnerabilities that result from the use of these languages in the kernel. In order to achieve this, kalloc_type implements mitigations such as type isolation in order to prevent type confusion and buffer overflow vulnerabilities. Ultimately, the prevention of privilege escalation is intended.
References
IOS
iOS | Security and privacy of iOS | [
"Technology",
"Engineering"
] | 1,964 | [
"Mobile security",
"Cybersecurity engineering"
] |
76,277,890 | https://en.wikipedia.org/wiki/JADES-GS-z7-01-QU | JADES-GS-z7-01-QU (also known as JADES-GS+53.15508-27.80178) is a Lyman-break galaxy, first identified in 2010, located in the constellation Fornax. It formed around 700 million years after the birth of the universe, after which it suddenly stopped creating new stars. It experienced rapid star formation around 80 million years before the epoch of observation, lasting for at least 30 million years, before ending around 10-20 million years before the epoch of observation. It is the oldest and most distant "dead" galaxy so far discovered.
Discovery
It was first discovered in 2010 and identified as a Lyman-break galaxy using imaging by Oesch et al., but was too faint for spectroscopy observations – particularly at the rest-frame optical wavelengths necessary to confirm quiescence. In 2022, following the launch of the James Webb Space Telescope (JWST), the galaxy was observed with the JWST camera NIRCam and spectrograph NIRSpec/MSA as part of the JWST Advanced Deep Extragalactic Survey (JADES), which found it to be quenched (i.e., non star-forming) and with a relatively low stellar mass, around the same as the Small Magellanic Cloud (SMC).
Properties
The JWST's NIRSpec observed it to have a very blue spectrum with a U-V colour of mag, a Balmer break, and no nebular emission lines.
Implications
Usually, such quenching of star formation occurs either in very low-mass galaxies, or much later in the universe's timeline. However, the discovery implies that the current models of galaxy evolution may be incomplete or inaccurate.
References
Galaxies discovered in the 21st century
Galaxies
Fornax | JADES-GS-z7-01-QU | [
"Astronomy"
] | 374 | [
"Fornax",
"Constellations"
] |
76,278,203 | https://en.wikipedia.org/wiki/Yolanda%20Gonz%C3%A1lez%20%28activist%29 | Yolanda González Martín (20 January 1961 – 1 February 1980) was a Spanish student and communist militant murdered by two members of New Force.
Biography
Originally from Deusto, Bilbao, González moved to Madrid to study electronics. To fund her education, she worked as a cleaner. She became the student representative of the vocational training school where she studied. She was also a member of the Workers Socialist Party. In February 1980, she was kidnapped, tortured and murdered by some members of New Force. Her body was found on a roadside near Madrid. The organization Batallón Vasco Español claimed responsibility for her murder. On the same day the organisation also murdered Jesús María Zubikarai Badiola in Eibar.
The perpetrators of González' murder were Emilio Hellín and Ignacio Abad Velázquez, who were arrested and sentenced to prison terms. Hellin was sentenced to 43 years in prison, of which he served only 14. In February 2013, El País reported that Hellin, under a false name, was working in communications technology for the Spanish security forces.
Legacy
On multiple anniversary years of her murder, González' relatives and neighbours have led calls for further justice and reparation. In 2014 Isabel Rodríguez directed the documentary "Yolanda en el País de los estudiantes", which recounts the kidnapping and subsequent murder of González by the Batallón Vasco-Español.
In 2018 Carlos Fonseca wrote No te olvides de mí: Yolanda González, el crimen más brutal de la Transición. This book brought together a range of sources to focus on her murder.
Both a garden and a public square have been named in her honour. In 2015, the garden Jardines de Yolanda González Martín was named after her in Madrid. In 2018 the sign for the gardens was defaced by fascists. In 2016 there a small square in Deustu was named in her honour.
References
External links
1961 births
1980 deaths
Basque women
Electrical engineers
Murdered students
People from Bilbao
Spanish communists | Yolanda González (activist) | [
"Engineering"
] | 414 | [
"Electrical engineering",
"Electrical engineers"
] |
76,278,893 | https://en.wikipedia.org/wiki/Tetramesityl%20compounds | Homoleptic tetra-mesityl complexes of transition metals in the +4 oxidation state, (IV), denoted as M(mes)4, constitute a category of organometallic substances that remain relatively unexplored. Characterized by tetrahedral coordination geometry, these compounds exhibit distinctive electrochemical, magnetic, and optical properties. Their unique attributes surpass those of their isostructural counterparts in group 14, commonly employed as fundamental components in advanced molecular materials like covalent- and metal–organic frameworks, polymers, self-assembled monolayers, and single-molecule electronic devices. Recent advancements, showcase the potential of modular, isostructural M(aryl) units in providing novel avenues for adjusting the electrochemical energy storage capacity, electrocatalytic functionality, and electrical conductivity/conductance of such materials, opening up various applications.
The synthesis and reaction chemistry of several homoleptic transition metal tetramesityl complexes has been reported, and conclusive identification has been provided through X-ray structural studies. Among the various M(aryl)4 materials, Os(IV) and Ru(IV) are particularly noteworthy, especially when they feature ortho-methylated sigma-aryl ligands. This is because these compounds exhibit remarkable robustness, as their stability can be attributed to a d4 low-spin electronic configuration, with the ligand methyl groups effectively inhibiting decomposition pathways such as reductive elimination and ortho-hydrogen abstraction. These compounds can be purified through air chromatography and their aryl ligands can be subjected to chemical functionalization using various methods such as bromination, Suzuki coupling, and Friedel-Crafts acylation. Os(aryl)4 compounds have rich redox chemistry, which allows for the early isolation of a stable paramagnetic Os(V) complex.
Synthesis
Tetramesityl vanadium
Trimesitylvanadium was first reported by Seidel and Kreisel in 1974 with the formula V(C9H11)3(THF)n. They then moved on to explore the synthesis tetramesityl vanadium compounds. Tetramesityl vanadium was prepared by adding one equivalent of mesLi to V(mes) in THF-Et2O to form this intermidate, V(mes)4Li. Air oxidation of the intermediate formed V(mes)4. An X-ray study shows V(mes)4, to have a slightly distorted tetrahedral structure.
Tetramesityl iridium
The synthesis, X-ray structure and reactions of tretra-(mesityl)rhodium(IV) (mesityl = 2,4,6-trimethylphenyl, mes) was described. Hursthouse et al. reported the synthesis of Ir(mes)4, along with the X-ray crystal structure.
The reaction of partially dehydraterd IrCl3(nH2O) with 2,4,6-trimethylphenyllithium at -20 °C, resulted in the tetrakis(mesityl)ruthenium complex.
No product was obtained when tetrahydrofuran was used as a solvent although Ir(mes)4, is stable in tetrahydrofuran. The yield, which never exceed about 20%, was dependent on the IrCl3(nH2O) batch and on the drying process. The results showcased that the reaction of IrCl3 results in the generation of an iridium(IV) compound. One possible explanation had to do with a disproportionation reaction, as no other product could be isolated.
A possible intermediate could have been Li[Ir(mes)4] but, Ir(mes)3 , does not react with Li(mes) in Et2O and careful air-oxidation of the ether solution gives no Ir(mes)4.
The product was obtained by evaporation, extraction of the residue with hexane, and crystallization at -20 °C. The resulting brown crystals had a melting point of 138-139 °C and were obtained in a yield of about 15%. The remaining substance after hexane extraction is black in color and is insoluble in organic solvents. The tetramesityl compound is stable in both solid and hexane solution states even when exposed to air. However, if it is heated in an air environment, it undergoes decomposition, leading to the formation of a green, diamagnetic substance.
The tetramesityl compound's structure has been determined through X-ray crystallography. The geometry of the compound is best described as distorted tetrahedral, with C-Ir-C angles ranging from 89.0 to 123.9 degrees. The Ir-C bond lengths range from 1.99 to 2.02 A. The distortion in the low-spin iridium(IV) system is likely due to steric factors, which result from the distribution and orientation of the ligands in a way that minimizes non-bonding interactions between them. The electronic properties of the system are not likely to be the origin of the distortion.
Homoleptic tetramesityl ruthenium(IV) complex
Previously, Wilkinson and his colleagues reported a series of tetra-arylruthenium(IV) complexes. The procedure follows RuCl3(tht), tht = tetrahydrothiophene, in Et2O at -78 °C was added a solution of Mg(mes)2(thf), thf = tetrahydrofuran with vigorous stirring. After warming and stirring at room temperature the solution was evaporated under vacuum and the residue extracted with light petroleum. The extracts were reduced, filtered and cooled to give feathery crystals with 18% yield.
In order to improve the yield of tetra-mes ruthenium(IV), complexes recent advances have synthesized homoleptic tetraarylruthenium(IV) complex Ru(2,4,5-Me3C6H2)4with a moderate yield of 37%. The procedure follows [Ru(acac)3] in THF at -78 °C was added to a 7 equiv. of (2,4,5-Me3C6H2)MgBr in THF.
The resulting brown mixture was stirred at room temperature overnight and followed by column chromatography in air, afforded the homoleptic tetra-mes ruthenium(IV) complex [Ru(2,4,5-Me3C6H2)4] as a purple crystalline solid in 37% isolated yield. The geometry around the central ruthenium atom is a slightly distorted tetrahedral. The C-Ru-C bond angles in the complex [Ru(2,4,5-Me3C6H2)4] are 98.9(6)–117.4(6)°. This is possibly as a result of the steric effect of two ortho-methyl moieties in mesityl groups.
Osmium(IV) tetramesityl complex
Obtaining Os(aryl)4 through the most common reaction of aryl Grignard reagents with OsO4 often results in poor yields, usually ≤34%. Moreover, the high toxicity of OsO4 and the presence of monooxo(tetraaryl)osmium(vi) and bisoxo(diaryl)osmium(vi) side products add extra complications to the purification process. Therefore, it is desirable to develop higher-yielding preparative approaches using alternative starting reagents.
Recent work has attempted to address the issue surrounding yields of Os(aryl)4 complexes. with an improved synthetic route to osmium(IV) tetraaryl complexes, starting from new tetra-n-octylammonium hexahaloosmate(IV) precursors (Oct4N)2[OsBr6]. This intermediate reacts with mesitylmagnesium bromide to obtain Os(mesityl)4 with an isolated yield of 5%.
This complex comprises previously inaccessible sterically demanding 2,6-dimethyl-substituted aryl ligands. Through their density functional theory (DFT) calculations, they were able to determine why they obtained such a low yield. The four mesityl groups of Os(mesityl)4 are arranged in a particularly distorted tetrahedral geometry (T-value = 8.02, C–Os–C angles between 98.4–117.2°). This analysis further supports the view that steric constraints due to 2,6-dimethyl substituents contribute to the lower synthetic yield.
Reactivity
There have been papers describing the X-ray structures, reactivity, spectroscopic, and electrochemical behavior of a series of ruthenium and osmium tetraaryl complexes. The tetra-o-tolyls of ruthenium and osmium have isostructural properties, with tetrahedral coordination environments around the metal atoms. Complexes of both metals are diamagnetic and show four equivalent o-tolyl groups in the 'H NMR spectrum. The ruthenium aryl is thermally very robust and exhibits the parent ion in the mass spectrum, as well as peaks due to sequential loss of o-tolyl groups.
References
Organometallic compounds
Transition metal compounds | Tetramesityl compounds | [
"Chemistry"
] | 1,989 | [
"Organic compounds",
"Organometallic compounds",
"Organometallic chemistry",
"Inorganic compounds"
] |
76,286,692 | https://en.wikipedia.org/wiki/Manoir%20de%20Venevelles | The Manoir de Venevelles, or Château de Venevelles, is a 15th-century manor house in the commune of Luché-Pringé, in the Sarthe departement of France. Established in the 11th century at the bottom of the Aune valley, at the foot of a wooded hill, the manor was rebuilt after the Hundred Years' War by the d'Espaigne family. Under the impetus of Henri-Paul d'Espaigne and Suzanne Le Vasseur, it became a major center of Calvinism in Anjou in the mid-17th century.
History
Origins of the château
Located on the borders of Maine, Anjou and Touraine, Venevelles lies at the bottom of a wooded hill that was once the site of a Roman castrum. Venevelles' riverside position, along a Roman road that linked Saint-Jean-de-la-Motte to Le Lude, defended access to the Loir valley. The name Venevelles comes from the Gallic verna, meaning "alder", and val, meaning "valley". The name "vallée des Aulnes" or "vallée de l'Aulne" comes from the site's location on the banks of the river Aune.
The origins of the first owners of the Vénevelles land are not well known. At the end of the 11th century, it belonged to Algerius de Venevelles, a monk from the Abbey of Saint-Aubin in Angers, on which the priory of Luché depended. Herbert d'Espaigne, a modest seigneur from Saint-Gervais-en-Belin, was probably the first d'Espaigne to settle in Venevelles. He appears at the end of the 13th century as seigneur of Venevelles, Aunay and Coullaines. The d'Espaigne family remained owners until the French Revolution, and rebuilt the château after the Hundred Years' War. Marie de Pons, daughter of Jacques de Pons, baron of Mirambeau and Champniers in Périgord, and Marie de La Porte, lady of Champniers and Chambon, married Paul d'Espeigne, lord of Vennevelles and Coulaines, in her first marriage; then, in her second marriage, she married Gédéon de Pressac, lord of Pressac and Lioncel.
Modern period
The importance and renown of Venevelles grew in the 17th century under the impetus of Henri-Paul d'Espaigne. Gentleman of the King's Chamber, he took part in the siege of Belfort alongside Marshal Henri de La Ferté-Senneterre, then became governor of the town. The land of Venevelles was made a marquisate in his favor in 1654. Henri-Paul d'Espaigne married Suzanne Le Vasseur, heiress of the seigneurs de Cogners, in 1643. Both fervent supporters of the "Protestant Reformed Religion", they made Venevelles one of the most active Calvinist centers in the region, and sent their children to study at the Saumur academy. In memory of this period, the castle's southeast tower is nicknamed the "Huguenotière". Venevelles became the preferred meeting place for Protestant groups from the surrounding area, such as those from Pringé, Mansigné and Dissé.
Henri-Paul d'Espaigne and Suzanne Le Vasseur continued the transformation of the château, transforming the late 15th-century fortified house into a building in keeping with the tastes of the time. While it's not certain that they built the two Louis XIII-style pavilions framing the outbuildings, there is evidence that they did build the one to the south (dated 1652 and probably designed by Le Lude architect Jean Hérault). They had the house extensively remodeled, removing an interior floor to create a noble floor with a high ceiling, and had a grand staircase built, followed by a drawbridge to access the park. The latter was probably built in 1650 by a certain Gaspard Dauphin, a garden contractor in Courcelles. Work continued after the marquis's death in 1656, under the direction of his wife, Suzanne Le Vasseur. Ruined, she sold the estate shortly before her death to her son, who had to part with almost half the leased property of the Venevelles estate to cover his debts. Protestant activity continued at Venevelles, leading to the occupation of the château by the king's dragoons in 1686.
Having finally abjured the Protestant religion, the d'Espaigne family distinguished themselves in the eighteenth century by serving in the armies. Two of them were made knights of the Order of Saint-Louis. Seigneur de Venevelles à l'aube de la Révolution, Henri-Jacques d'Espaigne de Venevelles émigre comme de nombreux nobles et rejoint l'armée de Condé. Château de Venevelles was sold as bien national in 1799 to citoyen Jouanneau. The widow of Henri-Jacques d'Espaigne, Alexandrine-Thérèse de Nieul managed to buy back the estate in 1802, but sold it five years later in view of the heavy expenditure required to maintain the château.
Contemporary period
In 1807, the property was purchased by Armand Constant Lebaigue, a member of the Parisian bourgeoisie who later became mayor of Luché. On his death in 1859, his granddaughter Marie Louise de Boucher, wife of Jacques de Chabot, inherited the estate and sold it to the Marquis de Brémond in 1887. The Brémond family lived little in Venevelles, occasionally renting the château, before selling it to a notary in La Flèche in 1920, who sold it four years later to an estate agent. A Japanese painter, Toyosaku Saïto, acquired the château in 1926 and moved in with his wife. Musicologist and organist Norbert Dufourcq became the owner of Château de Venevelles in 1955, and on January 21, 1963, the château was listed as a monument historique. As a plaque unveiled by the Préfet de la Sarthe in the château's entrance recalls, for almost thirty years the Dufourcqs were passionate about Venevelles, undertaking major restorations and truly saving the edifice. At the end of his life, thanks to the discovery of local archives, Norbert Dufourcq wrote his last book: Nobles et paysans aux confins du Maine et de l'Anjou: La seigneurie de Venevelles. A historian's work, based on extensive research, this book, with a preface by Jean Favier, is the main source of information on the seigneury of Venevelles.
Description
The Manoir de Venevelles sits at the bottom of an east-west valley, at the foot of a wooded hill, at the confluence of the River Aune and its tributary the Casseau. The manor house is surrounded by a wide, deep moat, fed by river water and regulated by a mill a few meters upstream. It was defended by a double body of water: the moat surrounding the quadrilateral on which the buildings were built, and the stream itself, which completely encircled this first defensive organization by displacing the riverbed, probably in the High Middle Ages. In the first third of the century (between 1810 and 1846, dates provided by land registers), the northern branches of the moat and the river were filled in.
Although the lords of Venevelles have been mentioned since the end of the 11th century, no remains of the original château can be found in the current building. Most of the manor's construction dates from the late 15th century. It comprises a central dwelling, built between 1460 and 1480, set at right-angles to each other and framed by two turrets, one facing north-west, the other, nicknamed the "Huguenotière", facing south-east. Two outbuildings were added in the early 16th century, one of which included a chapel blessed in 1503 by Cardinal de Luxembourg, Bishop of Le Mans. The chapel features two Plantagenet-style pointed vaults. The four corner pavilions were built in the 16th and 17th centuries.
Located to the north of the central dwelling, from which it is separated by the vast courtyard of honour, the farmhouse, built during the 16th century, is a long building flanked by two corner pavilions. The entrance gate, once fitted with a drawbridge, dates from 1720 and certainly replaced a 15th-century fortified postern. A second gate surmounts the west moat, which separates the main courtyard from a formal park. Built in 1657, its two pillars bear the initials of Paul-Henri d'Espaigne and Suzanne Le Vasseur.
Several sources attest to the existence of a vast network of underground galleries, one of which linked the Venevelles manor house to the Château de la Grifferie, also in the Luché-Pringé commune.
See also
List of castles in France
List of châteaux in France
Château
References
Works cited
Manor houses in France
Sarthe
Building | Manoir de Venevelles | [
"Engineering"
] | 1,946 | [
"Construction",
"Building"
] |
76,292,092 | https://en.wikipedia.org/wiki/Julia%20Lawall | Julia Laetitia Lawall is a computer scientist specializing in programming languages. Educated in the US, she has worked in the US, Denmark, and France, where she is a director of research for Inria. She is one of the developers of Coccinelle, a tool for finding patterns and making systematic transformations of source code, and she has also done research on domain-specific languages for operating systems.
Education and career
Lawall majored in mathematics at Oberlin College, graduating in 1986, and began her graduate studies in computer science at Carnegie Mellon University. She has a Ph.D. from Indiana University Bloomington, completed in 1994. Her dissertation, Continuation Introduction and Elimination in Higher-Order Programming Languages, was jointly supervised by Daniel P. Friedman and Olivier Danvy.
After completing her doctorate, she worked with Harry Mairson in the Logic and Computation group at Brandeis University in Boston, and at the Research Institute of Computer Science and Random Systems (IRISA) in Rennes, France, before taking a faculty position in the Department of Computer Science (DIKU) of the University of Copenhagen. She moved from Copenhagen to the French Institute for Research in Computer Science and Automation (Inria) in 2011; at Inria, she directs the Whisper project (well-honed infrastructure software for programming environments and runtimes). She also held an affiliation with the Laboratoire d'Informatique de Paris 6 of Sorbonne University from 2013 to 2020.
Recognition
Lawall has won two test-of-time awards for her publications. Her paper with Harry Mairson, "Optimality and inefficiency: what isn’t a cost model of the lambda calculus?", on the optimization criteria for finding normal forms in the lambda calculus, won the inaugural Most Influential ICFP Paper Award of ACM SIGPLAN, ten years after its publication in 1996. Additionally, her paper "Documenting and automating collateral evolutions in linux device drivers" (with Yoann Padioleau, René Rydhof Hansen, and Gilles Muller, in EuroSys 2008) won the 2018 EuroSys Test-of-Time Award. The paper introduced Cocinelle and described its use in maintaining device drivers to keep them synchronized with operating system changes.
References
External links
Home page
Year of birth missing (living people)
Living people
Computer scientists
Women computer scientists
Indiana University Bloomington alumni
Oberlin College alumni
Academic staff of the University of Copenhagen | Julia Lawall | [
"Technology"
] | 492 | [
"Computer science",
"Computer scientists"
] |
76,293,630 | https://en.wikipedia.org/wiki/NGC%20555 | NGC 555 is a lenticular galaxy located around 479 million light-years away in the constellation Cetus. NGC 555 was discovered in 1886 by the American astronomer Frank Muller. NGC 555 is not known to have much star formation, and it is not known to have an active galactic nucleus.
References
External links
005419
Cetus
Astronomical objects discovered in 1886
Discoveries by Frank Muller (astronomer)
476-12
J01271185-2245439
-04-04-014
005419
0555 | NGC 555 | [
"Astronomy"
] | 105 | [
"Cetus",
"Constellations"
] |
76,295,113 | https://en.wikipedia.org/wiki/Psychiatry%20Under%20the%20Influence | Psychiatry Under the Influence: Institutional Corruption, Social Injury, and Prescriptions for Reform is a 2015 book by Robert Whitaker and Lisa Cosgrove. The book discusses the use of psychiatric medication in the United States and is critical of the drug industry influence on the field of psychiatry.
See also
Bad Pharma
Big Pharma (book)
References
2015 non-fiction books
Books about mental health
History books about medicine
Books about drugs
Works about corruption
Pharmaceutical industry | Psychiatry Under the Influence | [
"Chemistry",
"Biology"
] | 92 | [
"Pharmaceutical industry",
"Pharmacology",
"Life sciences industry"
] |
76,298,725 | https://en.wikipedia.org/wiki/NGC%202139 | NGC 2139 is a barred spiral galaxy in the constellation of Lepus. It was discovered on November 17, 1784, by the German-English astronomer William Herschel. The galaxy is located at a distance of from the Sun and is receding with a radial velocity of 1,836 km/s.
The overall form of this galaxy is irregular with spiral arms and the appearance of tidal features, suggesting a potential recent merger event. There is no central bulge of significance. The morphological classification is SAB(rs)cd, which indicates a barred spiral galaxy (SAB) with a transitional inner ring structure (rs) and loosely wound spiral arms (cd). It is a star forming galaxy with a formation rate of ·yr−1. There is a plume extending to the south of the galaxy.
A luminous filament runs through the center of the galaxy, which includes a small nuclear cluster. This cluster is only old with a mass of . It is offset at a distance of 320 pc from the center of the galaxy and may come to rest there on a time scale of around 100 million years. The cluster is a source of X-ray emission.
Supernovae
Three supernovae have been observed in NGC 2139:
Robert Evans and associates discovered SN 1995ad (type II, mag. 14) on 28 September 1995. It was positioned in one of the spiral arms, west and south of the NGC 2139 nucleus. The recession velocity was consistent with that of the host galaxy.
SN 2022qhy (type Ibn, mag. 15.889) was discovered by ATLAS on 1 August 2022.
SN 2023zcu (type II, mag. 19.054) was discovered by ATLAS on 8 December 2023.
References
Barred spiral galaxies
Peculiar galaxies
Lepus (constellation)
2139
18258
18258
-04-15-005
IC objects
Discoveries by William Herschel
17841117 | NGC 2139 | [
"Astronomy"
] | 393 | [
"Lepus (constellation)",
"Constellations"
] |
76,300,390 | https://en.wikipedia.org/wiki/NDHU%20College%20of%20Environmental%20Studies%20and%20Oceanography | NDHU College of Environmental Studies and Oceanography (NDHU CESO; ) is Taiwan's leading interdisciplinary school of Environmental Studies and Oceanography at National Dong Hwa University (NDHU). Founded in 2009, NDHU CESO is formed as Taiwan's first school for Environmental Studies through merger of Graduate Institute of Natural Resources Management, Graduate Institute of Environmental Policy, Graduate Institute of Ecological and Environmental Education, Graduate Institute of Earth Sciences, Graduate Institute of Marine Biology, and Graduate Institute of Biological Resources and Technology from National Dong Hwa University and National Hualien University of Education.
NDHU CESO offers Taiwan's first interdisciplinary MSc program for Humanity and Environmental Science through partnership with NDHU College of Humanities and Social Sciences and NDHU College of Indigenous Studies, and co-offer Future Earth Ecology Program with NTU and NTHU to nurture Taiwan's naturalist. NDHU CESO also has partnership with Nepal Ministry of Forests and Environment on environmental education training.
History
Prior to foundation
Graduate Institute of Natural Resources Management (1994-2009)
NDHU Graduate Institute of Natural Resource Management (GINRM) was established in 1994 as NDHU's founding institute and is affiliated with NDHU School of Management. It was the pioneer in the field of natural resource management in Taiwan. GINRM was founded by Dr. Hsu Kuo-Shih, the Founding Director of Taroko National Park, with a focus on natural resource management and nature conservation. Following rapid growth in the academic field of natural resource tourism and Environmental governance, it branched out to establish the Graduate Institute of Environmental Policy (GIEP) and Graduate Institute of Tourism and Recreation Management (GITRM).
Graduate Institute of Environmental Policy (1999-2009)
NDHU Graduate Institute of Environmental Policy (GIEP) was established in 1999. It was founded by Dr.Wang Hurng-Jyuhn, a Taiwan's scholar in environmental policy, and was Taiwan's first institute dedicated to environmental policy research. Its main focuses are environmental policy, environmental management, and sustainable development strategies, and Environmental governance between human societies and ecological environments.
Foundation
College of Environmental Studies (2009-2022)
With merger of National Dong Hwa University and National Hualien University of Education, NDHU College of Environmental Studies (CES) and Department of Natural Resource and Environmental Studies (NRES) was founded in 2009 through merger of Graduate Institute of Natural Resources Management, Graduate Institute of Environmental Policy, Graduate Institute of Ecological and Environmental Education, Graduate Institute of Earth Sciences, and Graduate Institute of Biological Resources and Technology from both university.
College of Marine Sciences (2005-2022)
NDHU College of Marine Sciences (CMS) was established in 2005 as a graduate school for Marine Sciences and Marine Biology. NDHU CMS was an academic partnership between National Dong Hwa University and National Museum of Marine Biology and Aquarium (NMMBA) in Kenting National Park, which set the first record on academic collaboration between higher education and museum in Taiwan. Meanwhile, it founded Graduate Institute of Marine Biodiversity and Evolutionary Biology and Graduate Institute of Marine Biotechnology to leverage research resources from NMMBA.
Nowaday
With interdisciplinary trend of sustainability studies for Environmental Studies and Oceanography, NDHU College of Environmental Studies and Oceanography was established through merger of NDHU College of Environmental Studies and College of Marine Sciences in 2022.
Academic
Ranking
According to Times Higher Education World University Ranking by Subject, NDHU CESO is ranked A- level in the world for Geology (4th in Taiwan), Ecology (4th in Taiwan), and Environment Science and Engineering (3rd in Taiwan).
The SCImago ranked NDHU CESO 3rd in Taiwan for Aquatic Science, 7th in Taiwan for Animal Science and Zoology. The Research.com ranked it 2nd in Taiwan for Ecology and Evolution.
Department and Graduate Institute
Department of Natural Resource and Environmental Studies
Graduate Institute of Marine Biology
Research centers
Center for Interdisciplinary Research on Ecology and Sustainability (CIRES)
The Center for Interdisciplinary Research on Ecology and Sustainability (CIRES) was established in 2020. CIRES aims to become a Asia's regional center platform for scientific exchange and collaborative research to promote resilience studies in social-ecological systems, advance the governance of social-ecological systems, and thereby address the increasingly severe environmental, social, and economic issues under the impact of global change.
Eastern Taiwan Earthquake Research Center (E-TEC)
With Support from National Science and Technology Council, NDHU Eastern Taiwan Earthquake Research Center was established through a collaborative effort of several academic institutions, including NDHU CESO, Central Weather Bureau, Academia Sinica Institute of Earth Sciences, National Center for Research on Earthquake Engineering, Central Geological Survey, National Taiwan University, National Cheng Kung University, and National Central University. NDHU E-TEC serves as an integrated platform and a vital research hub for earthquake studies in eastern Taiwan.
With its distinguished location on the continental collision between Philippine Sea Plate and Eurasian Plate in eastern Taiwan, making NDHU E-TEC an optimal natural laboratory for earthquake research. Particularly, the Huadong Valley, situated in the plate collision and subduction transition zone, is the region with the highest earthquake frequency in Taiwan. The establishment of NDHU E-TEC, in collaboration with national research resources and NDHU CESO, enables more precise observation and analysis of eastern Taiwan's geophysical structures, assesses potential major earthquake threats, and plays a crucial role in Taiwan's earthquake early warning, data integration, precursory research, and disaster prevention applications.
Taiwan Long-Term Socio-Ecological Research (LTSER)
Taiwan Long-Term Socio-Ecological Research (TLTSER) is an essential initiative addressing the interaction and evolution of social-ecological systems over time. These systems, comprising intertwined and evolving ecosystems and social structures, develop unique characteristics and dynamics through prolonged interactions. Understanding these interactions is crucial for constructing and managing social-ecological systems effectively. In Taiwan, the transformation triggered by extensive social-ecological changes and governmental policies poses numerous challenges to rural areas, including demographic shifts, land use changes, and local economic struggles, alongside the broader impacts of climate change policies like the "2050 zero carbon emission" goal.
The TLTSER focuses on study sites in Eastern Taiwan, specifically the Fenling District and Guangfu Township. Fenling, representing a typical rural socio-ecological system, is predominantly agricultural and exemplifies the broader trends affecting similar areas across Taiwan, such as shifts in land use and economic makeup. A notable change is the conversion of artificial forests to ground-mounted photovoltaic (PV) systems, with extensive areas earmarked for future PV installations. The proximity of these developments to villages, farmland, and forests raises significant questions about their impacts on local climates, biodiversity, and community well-being.
By monitoring these changes across various stages of PV system implementation, the TLTSER aims to provide a detailed understanding of the alterations in land use and their implications. This research is pivotal for addressing local environmental and social issues, offering a scientific basis for informed public policy and governance, and contributing to sustainable development and environmental conservation in Taiwan.
Academic programs
Graduate
Doctor of Philosophy (PhD)
The Doctoral program (PhD) at NDHU College of Environmental Studies and Oceanography is a full-time, in-residence program intended for students who plan scholarly careers involving research and teaching in Environmental Studies and Oceanography. There are two PhD programs:
PhD in Natural Resources and Environmental Studies
PhD in Marine Biology
Master of Science (MS)
Master of Science (MS) has four major tracks for MS students follow at NDHU College of Environmental Studies and Oceanography:
MS in Natural Resources and Environmental Studies
Concentration in Ecology and Conservation
Concentration in Environmental Education and Ecotourism
Concentration in Environmental Management and Environmental Policy
Concentration in Earth Science
MS in Humanity and Environmental Science
MS in Marine Biodiversity and Evolutionary Biology
MS in Marine Biotechnology
Undergraduate
NDHU College of Environmental Studies and Oceanography offers one program in different concentrations.
Bachelor of Science (BS) in Natural Resources and Environmental Studies
Concentration in Ecology and Conservation
Concentration in Environmental Management and Environmental Education
Concentration in Earth Science
These programs operate on a modular system where students design their curricula to pace their studies. They may also take modules of their interest, subject to any prerequisite requirements and to the availability of modules.
Dual Degree
NDHU College of Environmental Studies and Oceanography offers Dual-PhD in partnership with Simon Fraser University in Canada.
International Partnerships and Relations
NDHU College of Environmental Studies and Oceanography (NDHU CESO) has collaborative relationships with numerous higher education institutions and research institutes worldwide in the fields of environmental studies and oceanography, including University of California, San Diego Scripps Institution of Oceanography in USA, Oregon State University in USA, Marche Polytechnic University in Italy, Nausicaá Centre National de la Mer in France, University of Florida in USA, Simon Fraser University in Canada, Hokkaido University Faculty of Environmental Earth Science in Japan, Okayama University Faculty of Environmental Science and Technology in Japan, China University of Geosciences in Wuhan.
NDHU CESO also has long-term collaborations with Hokkaido University School of Environmental Earth Science, Zhejiang University College of Life Sciences, and China University of Geosciences in faculty and student exchanges, and fieldwork education.
Furthermore, NDHU CESO has signed cooperation agreements with Nepal Ministry of Forests and Environment and Wildlife Conservation Nepal Foundation to assist in training Nepalese environmental education personnel, making it the sole signing entity in Taiwan for Nepal.
In addition to academic exchanges, NDHU CESO hosts visits from Chinese University of Hong Kong Earth and Environmental Sciences Programme, University of Tokyo Earthquake Research Institute, Tohoku University International Research Institute of Disaster Science, Tokyo University of Science Department of Architecture, and German Research Centre for Geosciences (GFZ) to NDHU Eastern Taiwan Earthquake Center.
References
External links
National Dong Hwa University
C
Educational institutions established in 2009
2009 establishments in Taiwan
Environmental studies institutions in Taiwan
Oceanographic organizations
Environmental research institutes
Environmental studies organizations
Forestry education
International educational organizations
International research institutes | NDHU College of Environmental Studies and Oceanography | [
"Environmental_science"
] | 2,055 | [
"Environmental research institutes",
"Environmental research"
] |
76,300,478 | https://en.wikipedia.org/wiki/David%20Crich | David Crich (born July 21, 1959) is a British American organic chemist and a professor at the University of Georgia.
He is widely known for his involvement in the development of mechanistic and synthetic organic chemistry, carbohydrate chemistry and medicinal chemistry. He has supervised over 75 doctoral students and has published over 450 peer-reviewed articles in scientific journals. The Crich beta-mannosylation reaction is named after him. He has made seminal contributions to understanding chemical glycosylation mechanisms.
Education
Born in the town of Chesterfield England, Crich received a Bachelor of Science degree from the University of Surrey in 1981 before joining the group of Sir Derek Barton, Nobel Laureate, at the Institut de Chimie des Substances Naturelles (ICSN) in France. Under Barton, he learned free radical chemistry and was responsible for the development of the Barton decarboxylation reaction, for which he was awarded the degree of Docteur es Sciences by the Universite de Paris XI Paris-Sud University (Orsay) in 1984. Crich stayed at the ICSN as a postdoctoral fellow with Derek Barton and Pierre Potier from 1984 to 1985.
Career and research
Crich began his independent career in 1985 when he took up a lectureship in chemistry in the Christopher Ingold Laboratories at University College London (UCL) in London. After five years at UCL, Crich moved to the University of Illinois (UIC) in Chicago where he rose through the ranks to become Distinguished Professor of Organic Chemistry. It was at UIC where Crich discovered the Crich beta-mannosylation reaction. In 2007, Crich relocated to Wayne State University in Detroit as the Schaap Professor of Chemistry, before returning to the ICSN, where he was appointed the institute's director. Crich returned to Wayne State as the Schaap Professor in 2011 and stayed there until 2019 when he moved to the University of Georgia as the Georgia Research Alliance and David Chu Eminent Scholar in Drug Design.
Awards and honors
Academia des Sciences / Royal Society, Franco-British Prize (1989)
Royal Society of Chemistry, Corday-Morgan Medal (1990)
University of Illinois, University Scholar (1992)
Fellow of the A. P. Sloan Foundation (1994)
Royal Society of Chemistry, Carbohydrate Chemistry Award (1994)
Electronic Encyclopedia of Reagents for Organic Synthesis, Executive Editor (2002–2009)
Fellow of the Japan Society for the Promotion of Science (2006)
Honorary Doctor of Science, University of Derby (2007)
American Chemical Society, Wolfram Award (2008)
Electronic Encyclopedia of Reagents for Organic Synthesis, Editor in Chief (2009–2015)
American Chemical Society, Arthur C Cope Senior Scholar (2011)
European Carbohydrate Society, Emil Fischer Award (2011)
Royal Society of Chemistry, Haworth Memorial Lecturer and Medal (2014)
American Chemical Society, C. S. Hudson Award (2017)
International Carbohydrate Organization, Whistler Prize (2018)
American Chemical Society, James Flack Norris Award in Physical Organic Chemistry (2024)
National Academy of Inventors, Senior Member (2024)
References
Living people
1959 births
20th-century English chemists
21st-century British chemists
Academics of University College London
Alumni of the University of Surrey
British organic chemists
Paris-Sud University alumni
People from Chesterfield, Derbyshire | David Crich | [
"Chemistry"
] | 683 | [
"Organic chemists",
"British organic chemists"
] |
53,468,830 | https://en.wikipedia.org/wiki/Anti-periplanar | In organic chemistry, anti-periplanar, or antiperiplanar, describes the bond angle in a molecule. In this conformer, the dihedral angle of the bond and the bond is greater than +150° or less than −150° (Figures 1 and 2). Anti-periplanar is often used in textbooks to mean strictly anti-coplanar, with an dihedral angle of 180° (Figure 3). In a Newman projection, the molecule will be in a staggered arrangement with the anti-periplanar functional groups pointing up and down, 180° away from each other (see Figure 4). Figure 5 shows 2-chloro-2,3-dimethylbutane in a sawhorse projection with chlorine and a hydrogen anti-periplanar to each other.
Syn-periplanar or synperiplanar is similar to anti-periplanar. In the syn-periplanar conformer, the A and D are on the same side of the plane of the bond, with the dihedral angle of and between +30° and −30° (see Figure 2).
Molecular orbitals
An important factor in the antiperiplanar conformer is the interaction between molecular orbitals. Anti-periplanar geometry will put a bonding orbital and an anti-bonding orbital approximately parallel to each other, or syn-periplanar. Figure 6 is another representation of 2-chloro-2,3-dimethylbutane (Figure 5), showing the C–H bonding orbital, σC–H, and the C–Cl anti-bonding orbital, σ*C–Cl, syn-periplanar. The parallel orbitals can overlap and become involved in hyperconjugation. If the bonding orbital is an electron donor and the anti-bonding orbital is an electron acceptor, then the bonding orbital will be able to donate electronegativity into the anti-bonding orbital. This filled-to-unfilled donor-acceptor interaction has an overall stabilizing effect on the molecule. However, donation from a bonding orbital into an anti-bonding orbital will also result in the weakening of both of those bonds. In Figure 6, 2-chloro-2,3-dimethylbutane is stabilized through hyperconjugation from electron donation from σC-H into σ*C-Cl, but both C–H and C–Cl bonds are weakened. A molecular orbital diagram shows that the mixing of σC–H and σ*C–Cl in 2-chloro-2,3-dimethylbutane lowers the energy of both the orbitals (Figure 7).
Examples of anti-periplanar geometry in mechanisms
E2 mechanism
A bimolecular elimination reaction will occur in a molecule where the breaking carbon-hydrogen bond and the leaving group are anti-periplanar (Figure 8). This geometry is preferred because it aligns σC-H and σ*C-X orbitals. Figure 9 shows the σC-H orbital and the σ*C-X orbital parallel to each other, allowing the σC-H orbital to donate into the σ*C-X anti-bonding orbital through hyperconjugation. This serves to weaken C-H and C-X bond, both of which are broken in an E2 reaction. It also sets up the molecule to more easily move its σC-H electrons into a πC-C orbital (Figure 10).
Pinacol rearrangement
In the pinacol rearrangement, a methyl group is found anti-periplanar to an activated alcohol functional group. This places the σC–C orbital of the methyl group parallel with the σ*C–O orbital of the activated alcohol. Before the activated alcohol leaves as H2O the methyl bonding orbital donates into the C–O antibonding orbital, weakening both bonds. This hyperconjugation facilitates the 1,2-methyl shift that occurs to remove water. See Figure 11 for the mechanism.
History, etymology, and misuse
The term anti-periplanar was first coined by Klyne and Prelog in their work entitled "Description of steric relationships across single bonds", published in 1960. ‘Anti’ refers to the two functional groups lying on opposite sides of the plane of the bond. ‘Peri’ comes from the Greek word for ‘near’ and so periplanar means “approximately planar”. In their article “Periplanar or Coplanar?” Kane and Hersh point out that many organic textbooks use anti-periplanar to mean completely anti-planar, or anti-coplanar, which is technically incorrect.
References
Organic chemistry | Anti-periplanar | [
"Chemistry"
] | 997 | [
"nan"
] |
53,468,850 | https://en.wikipedia.org/wiki/Relationship%20register | A relationship register is an alternative to marriage that provides legal proof of a relationship. This may be useful in issues relating to tax, retirement accounts, government payments, immigration or medical emergencies. Most states and territories in Australia provide a relationship register, and similar registers exist in other jurisdictions, such as the Canadian province of Manitoba.
Effect on marriage statistics
Relationships recorded in these registers are not included in Australian marriage statistics, which the Australian Bureau of Statistics identified as a possible data anomaly. While marriage rates have declined, the recently introduced relationship registers have grown in use. Although some couples have registered relationships because they are prohibited from marrying under the federal Marriage Act 1961 as amended by the Marriage Amendment Act 2004, other couples have registered as an alternative to marriage, thus reducing the marriage rate.
References
Interpersonal relationships
Marriage, unions and partnerships in Australia | Relationship register | [
"Biology"
] | 166 | [
"Behavior",
"Interpersonal relationships",
"Human behavior"
] |
53,470,862 | https://en.wikipedia.org/wiki/NGC%205643 | NGC 5643 is an intermediate spiral galaxy in the constellation Lupus. Based on the tip of the red-giant branch distance indicator, it is located at a distance of about 40 million light-years (12.5 megaparsecs). NGC 5643 has an active galactic nucleus and is a type II Seyfert galaxy.
Observation history
The galaxy was first discovered by James Dunlop on May 10, 1826, with his 9-inch reflector telescope, who described it as exceedingly faint. The galaxy was also spotted by John Herschel and added to the General Catalogue of Nebulae and Clusters as number 3572. The galaxy is located only 15 degrees from the galactic plane.
Structure
NGC 5643 is a grand design spiral galaxy, with two well-defined, symmetric arms. In the circumnuclear region are other dust spirals, but the two main dust arms are wider. The galaxy is seen nearly face on, at an inclination of ~ 27°.
Active galactic nucleus
The galaxy has a low-luminosity active galactic nucleus of Seyfert 2 type and is also a luminous infrared galaxy. The galaxy has a double sided diffuse radiojet. The galaxy exhibits an extended emission line region elongated in a direction close to the radio position angle of 87°±3°. Chris Simpson et al. analysed images takes from the WFPC2 camera of the Hubble Space Telescope in [O III] λ5007 and Hα and found emission extending eastward for at least 1.8 kpc and in the [O III]/Hα map a well-defined V-shaped structure that they identified as the projection of a tridimensional ionisation cone, which shares the same axis with the radio emission. A dust lane perpendicular to this axis obstructs the nucleus from direct view. A disk of material was found when the data cubes of VLT were analysed. It is aligned with the nucleus and circles it and possibly provides gas to the active galactic nucleus. The mass of the supermassive black hole has been estimated based on the galaxy stellar velocity dispersion to be 106.4 M⊙. It has been proposed that the gas outflow has led to star formation on two locations on the bar of the galaxy which lie at the location where the gas from the nucleus encounters the dense material of the bar.
Via observations of the galaxy from the XMM Newton telescope in 2009, the galaxy is found to have a Compton–thick active galactic nucleus. Also the galaxy emits soft X-rays, mainly from photoionized matter. The presence of the compton-thick column which obstructs the nucleus was confirmed from observations by NuSTAR.
Ultraluminous X-ray source
In 2004, Guainazzi et al. detected in the images from XMM-Newton an ultraluminous X-ray source, named NGC 5643 ULX1, located within 0.8 arcminutes from the nucleus. The source outshone the nucleus in X-rays and if it is located within NGC 5643 its luminosity is over 1040 erg/s. Its luminosity is variable. The X-rays could be produced either by an advection dominated disc or a Comptonising corona and the X-ray source is considered to be a black hole of stellar origin of approximately 30 solar masses.
Supernovae
NGC 5643 has been the home of two supernovae:
SN 2013aa (typeIa, mag. 11.9) was discovered by Stuart Parker from New Zealand on 13 February 2013, as part of the Backyard Observatory Supernova Search. It was classified as a type Ia a few days before maximum brightness. It got as bright as magnitude 11.3, making it the brightest supernova of the year 2013.
SN 2017cbv (typeIa, mag. 16.0451) was discovered by the Distance Less Than 40 Mpc Survey (DLT40) on 10 March 2017. It increased in magnitude from 15.8 to 14.8 within the next day. It got as bright as magnitude 11.5, making it the brightest supernova of the year 2017.
Nearby galaxies
NGC 5643 has a satellite dwarf galaxy, ESO 273-014. NGC 5643 is the foremost member of a small galaxy group that also includes NGC 5530.
Image gallery
References
External links
Barred spiral galaxies
Seyfert galaxies
Lupus (constellation)
5643
51969
272-G016
-07-30-003
Galaxies discovered in 1826
Astronomical objects discovered in 1826
Discoveries by James Dunlop | NGC 5643 | [
"Astronomy"
] | 938 | [
"Constellations",
"Lupus (constellation)"
] |
53,470,897 | https://en.wikipedia.org/wiki/HrrF%20RNA | HrrF DNA (Haemophilus regulatory RNA responsive to iron Fe) is a small non-coding RNA involved in iron homeostasis in Haemophilus species. Orthologues exist only among other Pasteurellacae. Iron- regulated sRNAs JA01- JA04 were identified in related Aggregatibacter. It is an analog to PrrF and RyhB RNAs. HrrF is maximally expressed when iron levels are low. Ferric uptake regulator (Fur) binds upstream of the hrrF promoter. HrrF stability is not dependent on the RNA chaperone Hfq. RNA-seq has shown that HrrF targets are mRNAs of genes whose products are involved in molybdate uptake, deoxyribonucleotide synthesis, and amino acid synthesis.
See also
NrrF RNA
References
Non-coding RNA | HrrF RNA | [
"Chemistry"
] | 185 | [
"Biochemistry stubs",
"Molecular and cellular biology stubs"
] |
53,471,343 | https://en.wikipedia.org/wiki/Humean%20definition%20of%20causality | David Hume coined a sceptical, reductionist viewpoint on causality that inspired the logical-positivist definition of empirical law that "is a regularity or universal generalization of the form 'All Cs are Es' or, whenever C, then E". The Scottish philosopher and economist believed that human mind is not equipped with the a priori ability to observe causal relations. What can be experienced is one event following another. The reductionist approach to causation can be exemplified with the case of two billiard balls: one ball is moving, hits another one and stops, and the second ball is moving.
In A Treatise of Human Nature Hume coined two definitions of the cause in a following way:
also fixed eight general rules that can help in recognizing which objects are in cause-effect relation, the main four are as following:
See also
Humeanism
References
Further reading
Causality
Causality
Causality
Metaphysical properties | Humean definition of causality | [
"Physics"
] | 187 | [] |
53,473,574 | https://en.wikipedia.org/wiki/Periodic%20Tales | Periodic Tales: The Curious Lives of the Elements (also published as Periodic Tales: A Cultural History of the Elements, from Arsenic to Zinc) is a 2011 popular science and history book by English writer Hugh Aldersey-Williams, on the history and cultural associations of the chemical elements. The book is divided into five sections, "Power", "Fire", "Craft", "Beauty", and "Earth", which group elements according to their primary cultural connotations, rather than their position on the periodic table. For certain elements such as phosphorus, the author documents his attempts to obtain samples by reproducing the original method of discovery. He also visits the site of discovery of several elements uncovered in modern times, including the famed Ytterby mine in Sweden, from which seven new elements were isolated.
Reception
The book received mixed but generally positive reviews from The Daily Telegraph, Kirkus Reviews, Publishers Weekly, and Science News. The Telegraph described the book as "a 400-page love letter to the chemical elements", and "an agreeable jumble of anecdote, reflection and information, rather than a source of understanding". Robert Buntrock, reviewing the book for the Journal of Chemical Education, found it to be more accurate and more enjoyable than The Disappearing Spoon by Sam Kean, a book with similar subject matter and audience published the year before.
References
Books about the history of science
Periodic table in popular culture
Popular science books
Ecco Press books
2011 non-fiction books
Viking Press books | Periodic Tales | [
"Chemistry"
] | 309 | [
"Periodic table",
"Periodic table in popular culture"
] |
53,473,860 | https://en.wikipedia.org/wiki/NGC%206814 | NGC 6814 is an intermediate spiral galaxy in constellation Aquila. It is located at a distance of about 75 million light years from Earth, which, given its apparent dimensions, means that NGC 6814 is about 85,000 light years across. NGC 6814 has an extremely bright nucleus and is a type 1.5 Seyfert galaxy. The galaxy is also a highly variable source of X-ray radiation. The ultraviolet and optical emission also varies, although more smoothly, with time lag of two days. The cause of the lag and the smoothing of light curves is considered to be the reprocessing of the X-rays in the accretion disk. The cause of the active galactic nucleus is suspected to be a supermassive black hole with a mass about 18 million times that of the Sun.
Many regions of ionised gas are studded along the dusty spiral arms.
Gallery
References
External links
Intermediate spiral galaxies
Seyfert galaxies
Aquila (constellation)
6814
63545 | NGC 6814 | [
"Astronomy"
] | 207 | [
"Aquila (constellation)",
"Constellations"
] |
53,474,857 | https://en.wikipedia.org/wiki/4-Ipomeanol | 4-Ipomeanol (4-IPO) is a pulmonary pre-toxin isolated from sweet potatoes infected with the fungus Fusarium solani. One of the 4-IPO metabolites is toxic to the lungs, liver and kidney in humans and animals. This metabolite can covalently bind to proteins, thereby interfering with normal cell processes.
The toxic metabolite, an enedial, is mostly formed in the bronchiolar exocrine cells (club cells) in the lungs of rodents. Necrosis of bronchiolar cells is therefore the primary damaging effect of the toxin, due to this location of metabolism. The secondary pathological effects are edema, congestion and hemorrhage caused by the destruction of the bronchiolar exocrine cells. In humans the metabolite is mostly formed in the liver, and causes liver toxicity.
Structure and reactivity
4-Ipomeanol is a chemical compound belonging to the family of furans. It consists of a furan ring, which is substituted at the third carbon of the furan ring with a pentanone containing a hydroxyl group. A furan ring is a five-membered aromatic ring consisting of one oxygen atom and four carbon atoms; a pentanone is a ketone consisting of five carbon atoms. Other 3-substituted furans are ipomeanine (IPN), 1-ipomeanol (1-IPO) and 1,4-ipomeanol (DIOL), differing in the locations of the hydroxyl groups. 4-IPO has three functional groups which determine the molecule's reactivity. These are the furan ring, the ketone group and the alcohol group.
Reactivity of furan ring
The furan ring is aromatic according to Hückel’s rule, so the furan makes the compound relatively stable. Therefore, this ring will not react easily with other compounds. Furan is heterocyclic, which means that it is cyclic, but one or more of the ring atoms is not a carbon atom. In the case of furan this heteroatom is an oxygen atom. This atom is sp2 hybridized and has one lone pair in an sp2 orbital and a second lone pair in a p orbital, overlapping with the p orbitals of adjacent carbons. This results in a pi bond formation.
Reactivity of ketone
A ketone group is polar, as oxygen is more electronegative than carbon. Therefore, the carbonyl atom of the ketone group is electron deficient, thus electrophilic, and can easily react with nucleophiles. However, it does not undergo substitution reactions, as the attached molecule is a too strong base to be eliminated. As a result of this, irreversible nucleophilic addition reactions are possible: a nucleophile can add to the carbonyl carbon, but due to the lack of a good leaving group, no base is eliminated. This intermediate molecule takes up a proton, so a hydroxyl group is formed. When there is sufficient acid present, the hydroxyl group can be protonated further, making it a good leaving group. This functional group will then react as an alcohol group.
As described above is the basic reaction mechanism of ketones. In this way ketones can undergo several organic reactions, reacting with compounds like grignard reagents, acetylide, cyanide, and hydride ions, amines, water, alcohols and peroxyacids.
Reactivity of alcohol
The alcohol group is a strongly basic leaving group that cannot undergo nucleophilic substitution reactions. However, it becomes a better leaving group after protonation, which converts the leaving group from OH− to H2O. H2O is a weaker base than OH− and can thus undergo substitution reactions with weakly basic nucleophiles. This reaction occurs following a SN2 mechanism, as 4-IPO is a secondary alcohol.
Dehydration of the pentanone substituted alcohol group is also possible, following an E1 reaction mechanism. This reaction is acid-catalyzed and results in the loss of a water molecule. Like with the SN1 reaction, protonation of the leaving group is required first. Water then is eliminated, leaving behind a carbocation, which leads eventually to alkene formation.
Furthermore, secondary alcohols can undergo oxidation reactions. This results in the formation of a ketone.
Synthesis
4-IPO can be isolated from sweet potatoes infected with the fungus Fusarium solani. However, it can also be synthesized from the commercially available chemical diethyl 3,4-furandicarboxylate.
Partial hydrolysis of diethyl 3,4-furandicarboxylate (I) with an equimolar quantity of NaOH results in the monoester 4-(ethoxycarbonyl)furan-3-carboxylic acid (II) occurs. This is followed by decarboxylation by heating with a copper powder yielded ethyl 3-furoate (III). The Claisen condensation is used to form ethyl 3-furoylacetate (IV). By reacting with propylene oxide, lactone (V) is formed. Decarboxylation is achieved by gently heating lactone in the presence of diluted acid (VI).
Metabolism
Metabolic activation of 4-IPO occurs by one of the enzymes of the cytochrome P450 (CYP) superfamily. The oxidation of the furan ring leads to the formation of an unstable epoxide (cyclic ester with a three-atom ring), so an alkylating intermediate species, 4-IPO enedial, is formed.
In rodents it is CYP4B1 that activates 4-IPO [1], an enzyme of the CYP4 family, of which the CYP4B subfamily is involved in the fatty acid metabolism. CYP4B1 is present in high levels in the lungs and its affinity for 4-IPO is greater than for liver CYP enzymes. Therefore, the activated form of 4-IPO is mainly toxic to the lungs in rodents.
However, in humans the reactivity of CYP4B1 is different and it does not activate 4-IPO. The CYP enzymes CYP1A2 and CYP3A4 are active in the liver and are similar to the rodent CYP4B1. 4-IPO is thus metabolically activated by CYP1A2 and CYP3A4 in humans. These two enzymes are both part of several pathways involved in the drug metabolism. As both CYPs are mainly active in the liver, 4-IPO causes hepatotoxicity in humans.
In both rodents and humans phase I metabolism involves the biotransformation of 4-IPO into an epoxide intermediate by CYPs. This epoxide is unstable, so it degrades into an enedial intermediate. The enedial intermediate is toxic, as it can bind to proteins. However, it can be detoxified in phase II metabolism, in which the enedial can be conjugated with either N-acetyl lysine (NAL) or N-acetyl cysteine (NAC). This results in a NAL/NAC-IPO adduct, which can be excreted. Furthermore, 4-IPO can directly undergo phase II metabolism, by conjugating glucuronosyl to the hydroxyl group of 4-IPO by uridine 5’-diphospho-glucuronosyltransferase (UGT), forming 4-IPO glucuronide. This can, like the NAL/NAC-IPO adduct, be excreted. However, the major pathway involves the enedial intermediate and the NAL/NAC-IPO adduct is the major product of biotransformation.
In contrast with these findings of in vivo studies, several other pathways for biotransformation of 4-IPO are found in vitro. Next to oxidation of the furan ring of 4-IPO, so that the 4-IPO enedial is formed, the hydroxyl group of 4-IPO can be oxidized. Oxidation of this functional group leads to ketone formation, so IPN is formed. IPN can undergo oxidation of the furan ring by CYPs, like 4-IPO. After this bioactivation reaction, the product can be conjugated to glutathione (GSH) by glutathione-S-transferase (GST). Furthermore, 4-IPO can be reduced and DIOL is the product of this biotransformation. Finally, 4-IPO can interact with [[NADP+]], forming a molecule which contains 4-IPO and NADPH. Of these four pathways described, the oxidation to IPN and the reduction to DIOL are the major processes.
Next to the difference in possible metabolic reactions 4-IPO can undergo, there is also a difference in the metabolization of the reactive 4-IPO enedial. This compound can be metabolized by either UGT or GSH. Metabolization by UGT results in NAL/NAC-IPO adducts, while multiple products can be the result of GSH metabolism.
Interaction of the 4-IPO enedial with GSH leads both to a Michael adduct and a dihydrohydroxyfuran adduct. The Michael adduct is the product of a Michael addition (1,4-addition of a cysteine), of the cysteine in GSH at the 4-position of the enedial. This Michael adduct can undergo dehydration and forms, via a tricyclic 2’-pyrroline adduct (14), a mono-GSH pyrrole adduct (16). Another reaction the Michael adduct can undergo is again dehydration and conjugation with GSH. Via the formation of subsequently an imine, enamine and an iminium ion, a bis-GSH pyrrole adduct (18) is formed. Another reaction via which the Michael adduct can form a bis-GSH pyrrole adduct (20), is firstly by undergoing elimination of a ketone group, followed by again dehydration in combination with GSH conjugation.
The dihydrohydroxyfuran adduct can also undergo dehydration in combination with GSH conjugation in a similar way as the Michael adduct, which results in a bis-GSH pyrrole adduct (19). Furthermore, the dihydrohydroxyfuran can dehydrate and form a mono-GSH pyrrole adduct (17).
Pharmacological use
Distribution of 4-IPO across tissues shows the same patterns for intravenous, oral and intraperitoneal injection and peak concentrations are achieved one to two hours after administration. By then most of the 4-IPO will be located in the lungs, followed by liver, kidney and blood. Apart from having the highest 4-IPO concentration, lung cells also show the highest level of covalently bound 4-IPO. This is in contrast with the gut, where the most occurring form of 4-IPO is unbound. After four hours 4-IPO levels show a plateau which persists for 24 hours. 4-IPO molecules still present at that time are mostly bound to other macromolecules. The IC50 was determined by an automated cell culture growth inhibition assay which shows IC50 ranging from 2-8 mM, depending on the cell type. The IC50 was also determined by another group which found roughly the same.
Detoxification is suspected to occur primarily via glucuronidation of 4-IPO. Out of all the metabolites found in urine, the primary excretion pathway, 4-IPO glucuronide was the most abundant. Excretion of 4-IPO glucuronide can be increased when rats were treated with phenobarbital, which increases γ-aminobutyric acid (GABA) activity.
Half-life varies from species to species. In mice the half-life is approximately 33 minutes after intravenous injection of 20 mg/kg 4-IPO. This is lower in rats and dogs. Rats need around six minutes to reduce the 4-IPO concentration by half and dogs around ten minutes. Both were administered a single intravenous dose of 6 mg/kg.
Preclinical trials
Several in vitro experiments were performed to explore the possible uses of 4-IPO, which showed promising results. Different lung, ovarian, breast and melanoma cancer cell lines showed apoptosis or inhibited tumor growth when exposed to high levels of 4-IPO (100 ug/uL). These results could not be replicated in conventional cancer screens, probably due to the fact that 4-IPO metabolism relies on very specific enzymes and environments which could not be replicated by conventional screens. However, 4-IPO showed effects when exposed to human lung cell lines. Four cell lines were tested and two showed inhibited tumor growth. Both cell lines were non-small cell lung carcinoma, while the two cell lines with no effects were small cell tumors. Other experiments showed that 4-IPO reduced tumor growth in a microencapsulated tumor assay at a concentration of 25 mg/mL. Furthermore, covalent binding of 4-IPO intermediates was observed in fresh lung biopsies.
Phase I Trial
On the basis of this knowledge a phase I trial was performed to study the effects of 4-IPO on the human body. 34 men and 10 women with non-small cell lung cancer were tested. The trial showed no significant hematological or renal toxicity but also no effect on the tumor. Measurements with biopsies obtained from the patients showed an IC50 of 6 mM, which is around 75 times higher than the measured plasma concentrations and likely higher than the plasma concentration achievable in vivo.
Phase II Trial
An earlier phase I and pharmacological trial showed that hepatotoxicity is dose limiting in humans and not lung toxicity. Based on these results a phase II trial was conducted to test the effects of 4-IPO on patients with advanced measurable hepatocellular carcinoma. Nineteen patients were treated with 1032 mg/m2 4-IPO. One patient showed a brief reduction in metastasis in the lung, but the rest showed no significant effects. As a consequence the authors recommend that 4-IPO is not used for further testing.
Further use in cancer treatment
Recently 4-IPO has been used in experiments where it plays a role in T-cell therapy. Autologous T-cells can be altered to express tumor specific antigens. These cells will then bind to tumors and induce apoptosis. There are side-effects associated with this kind of treatment and 4-IPO can help to control those side effects. A suicide gene is needed to induce apoptosis in T-cells when needed. CYP4B1 is inactive in humans but with minor changes in the amino acid sequence it can be activated again. This would result in T-cell death when the cells are exposed to 4-IPO, because they metabolize 4-IPO efficiently.
Non toxic 4-IPO analogues are also capable of inhibiting nicotine-derived nitrosamine ketone (NNK) metabolism. NNK is a pre-carcinogen which is activated inside the lung. Out of the four analogues tested (4-hydroxy-lphenyl-1-pentanone (HPP); 7-hydroxy-1-phenyl-1-octanone (HPO); 4-hydroxy-1- (2-thienyl)-1-pentanone (HTP); 4-hydroxy-l-(3-pyridyl)-l-pentanone (HPYP)) HPP and HPO showed competitive and noncompetitive inhibition of NNK and it reduces tumor formation in mice.
Toxicity
4-IPO is a specific lethal toxicant which mainly targets bronchiolar exocrine cells in the smaller bronchioles of rodent and cattle lungs. With an increased dose it is also possible to affect other cells and the airway of organisms. Covalent binding of 4-IPO to members of the CYP family (mainly CYP4B1) eventually leads to biotransformation of 4-IPO into an enedial intermediate, which is able to bind to a variety of proteins. These binding events are permanent and responsible for 4-IPO toxicity. This will result in cytotoxicity and eventually necrosis of bronchiolar exocrine cells, while ciliated bronchiolar cells and other epithelial lung cells are not affected, due to lower levels of cytochrome proteins. Necrotic patches, also called lesions or primary pathological changes, can develop into edemas, resulting in thickening of the alveolar septum, congestion, and hemorrhage (secondary and tertiary pathological changes). Lethality is probably due to pulmonary edema. Prior to death the dogs also showed rapid and shallow respiration, while in rats labored respiration and lymphocyte depletion can be observed. The LD50 dose varies between different species. In female mice 21 mg/kg/day 4-IPO are sufficient while in male mice 35 mg/kg/day were necessary. 15 mg/kg 4-IPO intravenously administered into rats is lethal and in dogs this dose is 12 mg/kg. It is possible to increase the LD50 by 2–4.5 fold when individuals are treated with multiple non-toxic doses beforehand.
In humans, 4-IPO shows minimal effects in the lung because the enzymes needed for biotransformation of 4-IPO are not present. Instead the liver is affected, because human liver cells do contain enzymes to biotransform 4-IPO. Something similar can be observed in male mice. Apart from the effects seen in the lungs they also have certain enzymes in their kidney which can transform 4-IPO into its reactive intermediate. As a result, renal toxicity is observed. Female mice and immature male mice do not have these enzymes. Therefore, they are resistant to renal toxicity.
Effects on animals
4-IPO has, similar to humans, a toxic effect on animals. It is toxic to livestock and many laboratory animals. Male rabbits, mice, rats and hamsters were used to test the effect of 4-IPO on. In all four species, the lung was a major target. In the hamsters and mice additional liver necrosis and renal necrosis, respectively, was detected.
4-IPO can also threaten newborn calves. If they become exposed to 4-IPO it increases their susceptibility to bovine parainfluenza virus 3. Parainfluenza itself does not have severe health effects but together with other infections it can lead to complex enzootic pneumonia.
References
Toxins
3-Furyl compounds
Secondary alcohols | 4-Ipomeanol | [
"Environmental_science"
] | 4,091 | [
"Toxins",
"Toxicology"
] |
53,475,705 | https://en.wikipedia.org/wiki/Electromagnetically%20induced%20acoustic%20noise | Electromagnetically induced acoustic noise (and vibration), electromagnetically excited acoustic noise, or more commonly known as coil whine, is audible sound directly produced by materials vibrating under the excitation of electromagnetic forces.
Some examples of this noise include the mains hum, hum of transformers, the whine of some rotating electric machines, or the buzz of fluorescent lamps. The hissing of high voltage transmission lines is due to corona discharge, not magnetism.
The phenomenon is also called audible magnetic noise, electromagnetic acoustic noise, lamination vibration or electromagnetically induced acoustic noise, or more rarely, electrical noise, or "coil noise", depending on the application. The term electromagnetic noise is generally avoided as the term is used in the field of electromagnetic compatibility, dealing with radio frequencies. The term electrical noise describes electrical perturbations occurring in electronic circuits, not sound. For the latter use, the terms electromagnetic vibrations or magnetic vibrations, focusing on the structural phenomenon are less ambiguous.
Acoustic noise and vibrations due to electromagnetic forces can be seen as the reciprocal of microphonics, which describes how a mechanical vibration or acoustic noise can induce an undesired electrical perturbation.
General explanation
Electromagnetic forces can be defined as forces arising from the presence of an electromagnetic field.
Electromagnetic forces in the presence of a magnetic field include equivalent forces due to Maxwell stress tensor, magnetostriction and Lorentz force (also called Laplace force).
Maxwell forces, also called reluctances forces, are concentrated at the interface of high magnetic reluctivity changes, e.g. between air and a ferromagnetic material in electric machines; they are also responsible of the attraction or repulsion of two magnets facing each other. Magnetostriction forces are concentrated inside the ferromagnetic material itself. Lorentz or Laplace forces act on conductors plunged in an external magnetic field.
Equivalent electromagnetic forces due to the presence of an electrical field can involve electrostatic, electrostrictive and reverse piezoelectric effects.
These phenomena can potentially generate vibrations of the ferromagnetic, conductive parts, coils and permanent magnets of electrical, magnetic and electromechanical device, resulting in an audible sound if the frequency of vibrations lies between 20 Hz and 20 kHz, and if the sound level is high enough to be heard (e.g. large surface of radiation and large vibration levels). Vibration level is increased in case of a mechanical resonance, when electromagnetic forces match with a structural mode natural frequency of the active component (magnetic circuit, electromagnetic coil or electrical circuit) or of its enclosure.
The frequency of the noise depends on the nature of electromagnetic forces (quadratic or linear function of electrical field or magnetic field) and on the frequency content of the electromagnetic field (in particular if a DC component is present or not).
Electromagnetic noise and vibrations in electric machines
Electromagnetic torque, which can be calculated as the average value of the Maxwell stress tensor along the airgap, is one consequence of electromagnetic forces in electric machines. As a static force, it does not create vibrations nor acoustic noise. However torque ripple (also called cogging torque for permanent magnet synchronous machines in open circuit), which represents the harmonic variations of electromagnetic torque, is a dynamic force creating torsional vibrations of both rotor and stator. The torsional deflection of a simple cylinder cannot radiate efficiently acoustic noise, but with particular boundary conditions the stator can radiate acoustic noise under torque ripple excitation. Structure-borne noise can also be generated by torque ripple when rotor shaft line vibrations propagate to the frame and shaft line.
Some tangential magnetic force harmonics can directly create magnetic vibrations and acoustic noise when applied to the stator teeth: tangential forces create a bending moment of the stator teeth, resulting in radial vibrations of the yoke.
Besides tangential force harmonics, Maxwell stress also includes radial force harmonics responsible for radial vibrations of the yoke, which in turn can radiate acoustic noise.
Electromagnetic noise and vibrations in passive components
Inductors
In inductors, also called reactors or chokes, magnetic energy is stored in the airgap of the magnetic circuit, where large Maxwell forces apply. Resulting noise and vibrations depend on airgap material and magnetic circuit geometry.
Transformers
In transformers magnetic noise and vibrations are generated by several phenomena depending on the load case which include Lorentz force on the windings, Maxwell forces in the joints of the laminations, and magnetostriction inside the laminated core.
Capacitors
Capacitors are also subject to large electrostatic forces. When the capacitor voltage/current waveform is not constant and contains time harmonics, some harmonic electric forces appear and acoustic noise can be generated.
Ferroelectric capacitors also exhibit a piezoelectric effect that can be source of audible noise. This phenomenon is known as the "singing capacitor" effect.
Resonance effect in electrical machines
In radial flux rotating electric machines, resonance due to electromagnetic forces is particular as it occurs at two conditions: there must be a match between the exciting Maxwell force and the stator or rotor natural frequency, and between the stator or rotor modal shape and the exciting Maxwell harmonic wavenumber (periodicity of the force along the airgap).
As an example a resonance with the elliptical modal shape of the stator can occur if the force wavenumber is 2. Under resonance conditions, the maxima of the electromagnetic excitation along the airgap and the maxima of the modal shape displacement are in phase.
Numerical simulation
Methodology
The simulation of electromagnetically induced noise and vibrations is a multiphysic modeling process carried in three steps:
calculation of the electromagnetic forces
calculation of the resulting magnetic vibrations
calculation of the resulting magnetic noise
It is generally considered as a weakly coupled problem: the deformation of the structure under electromagnetic forces is assumed not to change significantly the electromagnetic field distribution and the resulting electromagnetic stress.
Application to electric machines
The assessment of audible magnetic noise in electrical machines can be done using three methods:
using dedicated electromagnetic and vibro-acoustic simulation software (e.g. MANATEE )
using electromagnetic (e.g. Flux, Jmag, Maxwell, Opera), structural (e.g. Ansys Mechanical, Nastran, Optistruct) and acoustic (e.g. Actran, LMS, Sysnoise) numerical software together with dedicated coupling methods
using multiphysics numerical simulation software environment (e.g. Comsol Multiphysics, Ansys Workbench)
Examples of device subject to electromagnetic noise and vibrations
Static devices
Static devices include electrical systems and components used in electric power storage or power conversion such as
inductors
transformers
power inverters
capacitors
resistors: the braking resistors of electric trains, used to dissipate electrical power when the catenary is not receptive during braking, can make electromagnetically induced acoustic noise
coils: in magnetic resonance imaging, "coil noise" is that part of total system noise attributed to the receiving coil, due to its non-zero temperature.
Rotating devices
Rotating devices include radial and axial flux rotating electric machines used for electrical to mechanical power conversion such as
induction motors
synchronous motors with permanent magnets or DC wound rotor
switched reluctance motors
In such device, dynamic electromagnetic forces come from variations of magnetic field, which either comes from a steady AC winding or a rotating DC field source (permanent magnet or DC winding).
Sources of magnetic noise and vibrations in electric machines
The harmonic electromagnetic forces responsible for magnetic noise and vibrations in a healthy machine can come from
Pulse-width modulation supply of the machine
slotting effects
magnetic saturation
In a faulty machine, additional noise and vibrations due to electromagnetic forces can come from
mechanical static and dynamic eccentricities
uneven air-gap
demagnetization
short circuits
missing magnetic wedges
Unbalanced Magnetic Pull (UMP) describes the electromagnetic equivalence of mechanical rotating unbalance: if electromagnetic forces are not balanced, a non-zero net magnetic force appears on stator and rotor. This force can excite the bending mode of the rotor and create additional vibration and noise.
Reduction of electromagnetic noise and vibrations
Reduction of magnetic noise and vibrations in electric machines
NVH mitigation techniques in electrical machines include
reducing the magnitude of electromagnetic excitations, independently of the structural response of the electrical machine
reducing the magnitude of the structural response, independently of the electromagnetic excitations
reducing the resonances occurring between electromagnetic excitations and structural modes
Electromagnetic noise and vibration mitigation techniques in electrical machines include:
choosing the right slot/pole combination and winding design
avoiding resonances match between stator and electromagnetic excitations
skewing the stator or the rotor
implementing pole shaping / pole shifting / pole pairing techniques
implementing harmonic current injection or spread spectrum PWM strategies
using notches / flux barriers on the stator or the rotor
increasing damping
increasing the frequency outside the audible frequency range
Reduction of "coil noise"
Coil noise mitigation actions include:
add some glue (e.g. a layer of glue is often added on the top of television coils ; over the years, this glue degrades and the sound level increases)
change the shape of the coil (e.g. change coil shape to a figure eight rather than a traditional coil shape)
isolate the coil from the rest of the device to minimize structure-borne noise
increase damping
Experimental illustrations
A varying electromagnetic force can be produced either by a moving source of DC magnetic field (e.g. rotating permanent magnet or rotating coil supplied with DC current), or by a steady source of AC magnetic field (e.g. a coil fed by a variable current).
Forced vibration by a rotating permanent magnet
This animation illustrates how a ferromagnetic sheet can be deformed due to the magnetic field of a rotating magnet. It corresponds to an ideal one pole pair permanent magnet synchronous machine with a slotless stator.
Acoustic resonance by a variable frequency coil
The resonance effect of magnetic vibration with a structural mode can be illustrated using a tuning fork made of iron. A prong of the tuning fork is wound with a coil fed by a variable frequency power supply. A variable flux density circulates between the two prongs and some dynamic magnetic forces appear between the two prongs at twice the supply frequency. When the exciting force frequency matches the fundamental mode of the tuning fork close to 400 Hz, a strong acoustic resonance occurs.
Examples of audio files
PMSM motor (traction application)
References
External links
Video of a resonating tuning fork magnetically excited by a variable frequency current on YouTube
Video of a tuning fork magnetically excited by a fixed frequency current on YouTube
Video of a ferromagnetic cylinder deformed by a rotating magnet on YouTube
Acoustics
Electromagnetism
Noise
Mechanical vibrations
Noise pollution
Sound | Electromagnetically induced acoustic noise | [
"Physics",
"Engineering"
] | 2,207 | [
"Structural engineering",
"Physical phenomena",
"Electromagnetism",
"Classical mechanics",
"Acoustics",
"Mechanics",
"Fundamental interactions",
"Mechanical vibrations"
] |
53,475,864 | https://en.wikipedia.org/wiki/Sally%20Eden | Sally Eden (1967–2016) was a British geographer and Professor of Human geography at the University of Hull.
Scholarly contributions
Eden’s research and writing focused on how society understands and manages the environment. It included issues of sustainable consumption, green lifestyles, environmental action and forms of public engagement with the environment.
In a series of research projects, Eden examined how scientific knowledge about the environment is used within and outside of government, how river restoration projects are designed and justified and how ordinary people get involved with and make sense of how environments are managed. In her writing she developed lines of analysis and argument drawing on concepts from human geography but also science and technology studies and environmental politics.
Eden's book ''Environmental Publics'' (Routledge 2017) argues that ‘the public’ is not one thing and their engagements with the environment take multiple forms.
Publications
Eden, S. “Environmental Publics”. London & New York: Routledge, 2017.
Eden, S. “Mucky carrots and other proxies: Problematising the knowledge-fix for sustainable and ethical consumption”. Geoforum 39(2), pp. 1044–1057, 2008.
Eden, S. “Being Fieldworthy: Environmental Knowledge Practices and the Space of the Field in Forest Certification”. Environment and Planning D: Society and Space 26, pp. 1018–1035, 2008. DOI: 10.1068/d3208
Eden, S. “Ecological versus Social Restoration? How urban river restoration challenges but also fails to challenge the science - policy nexus in the United Kingdom”. Environment and Planning C: Politics and Space 24(5), 2006.
Eden, S. “Environmental issues: sustainable progress?”. Progress in Human Geography 24(1), pp. 111–118, 2000.
Eden, S. “Environmental issues: knowledge, uncertainty and the environment”. Progress in Human Geography 22(3), pp. 425–432, 1998.
Eden, S. “Environmental Issues and Business: Implications of a Changing Agenda”. Chichester: John Wiley & Sons, 1996.
Eden, S. “Public participation in environmental policy: considering scientific, counter-scientific and non-scientific contributions”. Public Understanding of Science 5(3), 1996.
References
External links
Environmental Publics.
1967 births
Alumni of Durham University
English geographers
Environmental social scientists
Women geographers
Academics of the University of Hull
2016 deaths | Sally Eden | [
"Environmental_science"
] | 497 | [
"Environmental social scientists",
"Environmental social science"
] |
53,476,296 | https://en.wikipedia.org/wiki/Ballochmyle%20cup%20and%20ring%20marks | The Ballochmyle cup and ring marks were first recorded at Ballochmyle (NS 5107 2552), Mauchline, East Ayrshire, Scotland in 1986, very unusually carved on a vertical red sandstone cliff face, forming one of the most extensive areas of such carvings as yet found in Britain. They have been designated a scheduled monument.
Discovery
These carvings or petroglyphs were first recorded in 1986 (although a '1751' carved date suggests an earlier discovery) when the Kingencleugh Estate decided to clear an area of vegetation along the north side of the Liddell Burn that is a minor tributary stream of the River Ayr in an area famous for its quarrying of red sandstone. The removal of vegetation exposed the carvings that are distributed across two faces of a vertical outcrop of rock and they were reported to the Dick Institute in Kilmarnock. The presence of possible medieval carvings, the extensive quarrying with numerous workmen employed in the area, especially during the construction of the Ballochmyle Viaduct, emphasises how surprising it is that these glyphs were overlooked for so long, especially as they are only about 2 km south-east of Mauchline's town centre.
Description
The rock here is described as being a "pink dessert sandstone from the Permian age showing clear signs of dune bedding". The cup and ring marks are composed of two 'panels' with several hundred 'cup and ring' and other glyphs or carvings in a range of styles, ranging from single shallow cups through to deeper cups with multiple rings. Less common, but unique in the Scottish context are ‘square with cup’ carvings; ‘ringed stars’ are also present. Three deer-like carvings and some other inscriptions with Lombardic style letters were also carved into the rockface and these are thought to be medieval in date.
Several feet of soil were removed from the bottom of the corner that divides the two main halves of the site and this uncovered three 'trilithon-like' carvings and others may await discovery where the soil has not been removed. The carvings were protected by the vegetation and began to deteriorate after this was removed and in addition vandalism and theft of a panel has taken place. It is likely that they were historically hidden from direct view by trees and shrubs.
The Ballochmyle glyphs or motifs are carved on red sandstone, however they are found elsewhere on other sedimentary rocks such as Millstone Grits, as well as the harder igneous and metamorphic rocks such as granites and schists.
The basic 'cup' is the most common carving however a wide range of glyphs exist with single to multiple concentric circles that are sometimes cut through in various ways by channels, etc. Where concentric rings exist the central cup often appears to dominate in depth and size suggesting that they were subject to repeated reworking over a period of time. Some incomplete or poorly formed glyphs exist here suggesting that different persons were involved in making them and frequent overlays of existing glyphs with either 'cups' or 'cup rings' suggests that they were created over an extended period of time.
Studies suggest that distinct stylistic groupings may be present with one panel area having simple cups and cups with grooves, whilst another area has predominately bold cups with multiple concentric rings. An area with an apparent Lombardic style lettering may read 'ASAID' with two or three unreadable leading letters and a likely lost section. The final element is a date '1751' that is considered authentic but did not lead to further recorded investigation.
Evidence suggests that cup and ring art was created from the Neolithic through to the Bronze Age, that is approximately 4000 BC to 1500 BC.
Creation and meaning
Cup and ring mark stones are frequently found throughout Britain, with over 2500 sites in England alone, however an unusual feature of those at Ballochmyle is that they have been carved on nearly or actual vertical surfaces rather than horizontal and often 'altar-like' exposed stone outcrops. These types of carvings were created using 'hammerstones' or 'peckers', examples of these have been found elsewhere, hitting the surface of the rock repeatedly or using a grinding motion until the desired design was formed Some of the long grooves appear to be a series of cups that were then joined together. The soft nature of the stone at Ballochmyle gives insights into how the glyphs were created with many small holes that could not have been formed by a hammering action.
The contrast with the original rock surface and the effect of shadow and rain usually makes the markings stand out however hints of the use of coloured pigments have been found at other sites and such things as animal fat, charcoal, plants dyes, etc. could have been used during various types of ceremonies to enhance the glyphs or as part of their cultural use.
The frequency and widespread use of the same glyphs or motifs indicates that they had definite interpretive meanings and significance to the cultures that created them and these developed and then persisted over thousands of years. The locations indicate that these carvings were mostly for public display and not usually intended as part of secret practices where the fact that they were hidden was important.
It may be relevant that the Ballochmyle area has both spectacular geological formations and geographical features in addition to the presence of a significant liminal zone in the form of a major watercourse, the River Ayr. Carvings into rocks can have deeper meanings such as with the carved footprint Petrosomatoglyphs at Dunadd in Argyll, linking a person literally to the land. The concept of the Anima locus is pertinent here, that is the 'soul' of a place, its essential personality as perceived in the imagination and emotions of visitors. A concept linked to the belief in supernatural spirits of nature as residing in stones, springs, mountains, islands, trees, etc. A form of religious significance linked to life and death, past and present, real and spiritual worlds, etc. has been proposed.
A significant factor is that, as previously stated, they were created from Neolithic through to the Bronze Age, that is approximately 4000 BC to 1500 BC and they ceased when the Celtic Culture began to dominate and suppress older cultural practices. During this time smaller nomadic groups that might visit certain sites seasonally developed into sedentary communities with hierarchical leadership structures and specific communal religious practices.
Many 'galleries' of cup and ring mark art are in prominent places within the landscape, such as river gorges, waterfalls, outcrops, caves, etc. and it has been suggested that they may have defined territorial boundaries, either for a locality or for a significant land holding. Few prehistoric track ways have been positively identified however some link with the more practical aspects of Ley lines may be indicated by the observation that cup and ring art is sometimes found overlooking natural harbours, on prominent natural landscape features, in mountain passes, along valley sides, at the entrances to inland routes, etc.
It is thought that natural features of the rock faces may influence the cup and ring mark sizes, distribution and type in addition to 'framing' the carvings. Fissures, grooves, wind erosion marks, cracks, dune bedding, etc. may all have been regarded by the Cup and ring mark carvers as significant and meaningful in their own right to be copied, enhanced, removed or incorporated as possibly the work of their 'ancestors' or even the works of the gods themselves.
Some cup and ring mark panels may have only been used seasonally and the varying level of complexity at sites has been interpreted as being both more and less significant in terms of the level of meaning present.
The universality of cup and ring markings suggest a commonality of the origins of such glyphs that may relate to natural phenomena that are deemed significant, such as the concentricles that form on water when an object or offering is placed in it and although this may have been interpreted differently by the many cultures involved, the liminality with associated themes of thresholds and communication with the 'other side' may be one explanation for the use of cup and rings rather than the extensive use of glyphs such as ovals, boxes, triangles, star-shapes, etc.
Surveys of the markings
In 2015 AOC Archaeology group were employed by the Forestry Commission Scotland to carry out a survey of laser scanning and photogrammetry on the Ballochmyle cup and ring marks. Laser scanning recorded the glyphs in 3D in minute detail, taking millions of measurements. The Photogrammetry involved photographing the site from many different angles and then bringing the data together to create a 3D model. The RCAHMS carried out a survey on behalf of Historic Scotland in 1987 and a series of drawings were lodged with what is now Historic Environment Scotland.
See also
Dalgarven Mill – Museum of Ayrshire Country Life and Costume - The site of an unusual cup and ring mark stone.
References
Notes
References
Campbell, Thorbjørn (2003). Ayrshire. A Historical Guide. Edinburgh : Birlinn.
Love, Dane (2003). Ayrshire : Discovering a County. Ayr : Fort Publishing. .
Pennick, Nigel (1996). Celtic Sacred Landscapes. Thames & Hudson. . P. 13 - 15.
Sharpe, Kate, Barnett, Tertia et al. (2008). England's Rock Art. The Prehistoric Rock Art of England. English Heritage & Northumberland County Council. .
Stevenson, J.B. (2010). Cup-and-Ring Markings at Ballochmyle, Ayrshire. Glasgow Archaeological Journal. V.18, Issue 18, ISSN 0305-8980.
External links
Video footage of the Ballochmyle cup and ring marks
Medieval and Later Carvings at Ballochmyle
Exploring the designs and meanings of the rock carvings at Ballochmyle
Creative archaeological visualization of the rock art at Ballochmyle
The Modern Antiquarian - photographic record
Megalithic symbols
Rock art
Prehistoric art
History of East Ayrshire
Neolithic
Bronze Age
Scheduled monuments in East Ayrshire
Mauchline | Ballochmyle cup and ring marks | [
"Mathematics"
] | 2,059 | [
"Megalithic symbols",
"Symbols"
] |
53,476,663 | https://en.wikipedia.org/wiki/Erick%20M.%20Carreira | Erick M. Carreira (born 1963) is a Cuban-born American organic chemist and professor at ETH Zürich. He is known for his research group's work in total synthesis projects, particularly asymmetric synthesis of complex natural products. He became the editor-in-chief of the Journal of the American Chemical Society in 2021.
Early life and education
Carreira was born in 1963 in Havana, Cuba. He received his B.S. in 1984 from the University of Illinois at Urbana–Champaign, where he worked with Scott E. Denmark. He then began graduate work at Harvard University as a student of David A. Evans and received his Ph.D. in 1990. He was a postdoctoral fellow at the California Institute of Technology with Peter Dervan until he joined the faculty there in 1992.
Academic career
Carreira began his independent research career on the Caltech faculty and became a full professor in 1997. While there, he received several awards for successful new faculty and for his skilled teaching. He has been a full professor of chemistry at ETH Zürich since 1998.
Carreira has coauthored and coedited several major reference works in the total synthesis field, including volume 93 of Organic Syntheses. In 2019, Carreira was appointed as the editor-in-chief of Organic Letters published by the American Chemical Society, where he had previously served as an associate editor for 18 years. In April 2020, Carreira was elected for a membership in the National Academy of Sciences of the United States. In September 2020, he was appointed chief editor of the Journal of the American Chemical Society. Carreira is the first Hispanic American scientist to hold the position.
Carreira letters
The appointment reignited debate over a 1996 letter in which Carreira highlighted his expectations for long working hours in his research group, which were viewed as inappropriately demanding and demeaning by other professors. In response, Carreira released a statement disavowing the approach reflected in the letter. Carreira began his appointment in January 2021, succeeding Peter Stang. Carreira also wrote a letter in 1999 highlighting expectations for the scheduling of a student's thesis defense and non-permanence of PhD completion scheduling at Carreira's sole discretion. The terms of Carreira's request included restriction of all vacation time during the thesis writing process and held the student accountable for financial liabilities such as "rental agreements [and] airline change fees" incurred should Carreira decide that he needed to change the date of the defense . This letter was also published in response to Carreira's appointment to his JACS position.
Research
Research in Carreira's group focuses on total synthesis, particularly asymmetric (that is, enantioselective) synthesis of complex natural products. The group also works on applications of these methods to development of catalysts and to medicinal chemistry.
Awards and honors
Beckman Young Investigators Award, 1993
Fresenius Award, Phi Lambda Upsilon, 1996
American Chemical Society Award in Pure Chemistry, 1997
Thieme-IUPAC Prize, 2002
Ryoji Noyori Prize, 2021
Personal life
He has always enjoyed animals and owns 15 birds.
References
1963 births
Living people
American organic chemists
Academic staff of ETH Zurich
Harvard University alumni
Members of the United States National Academy of Sciences
California Institute of Technology faculty
American expatriate academics
American expatriates in Switzerland
20th-century American chemists
21st-century American chemists
American academic journal editors
Cuban emigrants to the United States
Recipients of the Presidential Early Career Award for Scientists and Engineers
University of Illinois College of Liberal Arts and Sciences alumni | Erick M. Carreira | [
"Chemistry"
] | 728 | [
"Organic chemists",
"American organic chemists"
] |
53,476,992 | https://en.wikipedia.org/wiki/Curie%E2%80%93von%20Schweidler%20law | The Curie–von Schweidler law refers to the response of dielectric material to the step input of a direct current (DC) voltage first observed by Jacques Curie and Egon Ritter von Schweidler.
Overview
According to this law, the current decays according to a power law:
where is the current at a given charging time, , and is the decay constant such that . Given that the dielectric has a finite conductance, the equation for current measured through a dielectric under a DC electrical field is:
where is a constant of proportionality. This stands in contrast to the Debye formulation, which states that the current is proportional an exponential function with a time constant, , according to:
.
The Curie–von Schweidler behavior has been observed in many instances such as those shown by Andrzej K. Jonscher and Jameson et al. It has been interpreted as a many-body problem by Jonscher, but can also be formulated as an infinite number of resistor-capacitor circuits. This comes from the fact that the power law can be expressed as:
where is the Gamma function. Effectively, this relationship shows the power law expression to be equivalent to an infinite weighted sum of Debye responses which is mathematically correct but not quite useful for the purpose of modelling and simulation. Interestingly, the power-law nature of the Curie–von Schweidler law motivated the birth of the fractional capacitor in electrical modelling and in describing anomalous dielectric behaviour. The fractional capacitor displays an interplay between a resistor and capacitor for values of lying between and .
The Curie-von Schweidler law corresponds to the time domain current response of the main dielectric models, such as the Cole-Cole_equation, the Cole-Davidson_equation, and the Havriliak–Negami_relaxation, for small time arguments.
Recently, Pandey gave a theoretical derivation of the Curie–von Schweidler law which also seems to be the first work that gave a physical interpretation to its parameters. Pandey assumed a series combination of a resistor, , and a capacitor with a linear time varying capacitance, , such that,
, , where is the constant geometric capacitance. He found,
, where is the applied constant voltage. A key intermediate finding in this derivation is that the charge accumulation in a capacitor with a time-varying capacitance should not be described by the conventional charge-voltage relation of the capacitor, , because it is only applicable for the case of a constant-capacitance capacitor and therefore it leads to inconsistent results. Rather, for time-varying capacitors the appropriate relation is given by the convolution of the capacitance with the first time-derivative of the voltage, i.e., . Surprisingly, the convolution relation reduces to the conventional relation in the case of the constant-capacitance capacitor. The results obtained by Pandey satisfy the experimental data quite well. Consequently, a physical interpretation of the fractional derivatives and the fractional capacitor are now available.
References
Dielectrics | Curie–von Schweidler law | [
"Physics"
] | 677 | [
"Materials",
"Dielectrics",
"Matter"
] |
53,477,184 | https://en.wikipedia.org/wiki/Timeline%20of%20the%20gunpowder%20age | This is a timeline of the history of gunpowder and related topics such as weapons, warfare, and industrial applications. The timeline covers the history of gunpowder from the first hints of its origin as a Taoist alchemical product in China until its replacement by smokeless powder in the late 19th century (from 1884 to the present day).
Pre-gunpowder formula
Major developments: Earliest stage of gunpowder development. Mentions of gunpowder ingredients and their uses in conjunction with each other.
9th century
Major developments: Earliest definite references to a gunpowder formula and awareness of its danger.
10th century
Major developments: Gunpowder is utilized in Chinese warfare and an assortment of gunpowder weapons appear. Fire arrows utilizing gunpowder as an incendiary appear in the early 900s and possibly rocket arrows as well by the end of the century. The gunpowder slow match is used for igniting flame throwers. The ancestor of firearms, the fire lance, also appears, but its usage in the 10th century is uncertain and no textual evidence for it exists during this period.
11th century
Major developments: The chemical formula for gunpowder is recorded in the Wujing Zongyao by 1044. Bombs appear in the early 11th century. Gunpowder becomes more common in the Song dynasty and production of gunpowder weapons is systematized. The Song court restricts trade of gunpowder ingredients with the Liao and Western Xia dynasties.
12th century
Major developments: Gunpowder fireworks are mentioned. Ships are equipped with trebuchets for hurling bombs. Earliest recorded usage of gunpowder artillery in ship to ship combat, first mention of the fire lance in battle, and the earliest possible depiction of a cannon appears.
13th century
Major developments: Bomb shells gain an iron casing. Fire lances are equipped with projectiles and reusable iron barrels. Rockets are used in warfare. "Fire emitting tubes" are produced in the Song dynasty by the mid-13th century and hand cannons are recorded to have been used in battle by the Yuan dynasty in 1287. The earliest extant cannons appear in China. The Mongols spread gunpowder weaponry to Japan, Southeast Asia, and possibly the Middle East as well as Europe. Europe and India both acquire gunpowder by the end of the century, but only in the Middle East are gunpowder weapons mentioned in any detail.
14th century
Major developments: Chinese gunpowder weaponry continues to advance with the development of one-piece cast iron cannons, accompanying carriages, and the addition of land mines, naval mines and rocket launchers. Earliest recorded instance of volley fire with gunpowder weaponry, by the Ming dynasty. The rest of the world catches up quickly and most of Eurasia acquires gunpowder weapons by the second half of the 14th century. Cannon development in Europe progresses rapidly and by 1374, cannons in Europe are able to breach a city wall for the first time. Breech loading cannons appear in Europe.
15th century
Major developments: Large-calibre artillery weighing several thousand kg are produced in Europe during the early 15th century and spread to the Ottoman Empire. Modifiable two wheeled gun carts known as limbers and caissons appear, greatly improving the mobility of artillery. The matchlock arquebus, the first firearm with a trigger mechanism, appears in Europe by 1475. Rifled barrels also appear in the late 15th century. The term musket is used for the first time in 1499. Rocket launchers are used in battle by the Ming dynasty and the Korean kingdom of Joseon develops a mobile rocket launcher vehicle called the hwacha. Chinese style bombs are used in Japan by 1468 at the latest.
16th century
Major developments: Matchlock firearms spread throughout Eurasia, reaching China and Japan by the mid-16th century. The volley fire technique is implemented using matchlock firearms by the Ottomans, Ming dynasty, and Dutch Republic by the end of the century. The arquebus is replaced by its heavier variant called the musket to combat heavily armoured troops. "Musket" becomes the dominant term for all shoulder arms fireweapons until the mid-19th century. The wheellock and flintlock trigger mechanisms are invented. Pistols and revolvers both appear during this period. Ottoman troops attach bayonets to their firearms. Both Europe and China develop handheld breech loading firearms. The star fort spreads across Europe in response to increasing effectiveness of siege artillery. The Ming dynasty uses gunpowder for hydraulic engineering.
17th century
Major developments: Bayonets spread across Eurasia. A paper cartridge is introduced by Gustavus Adolphus. Rifles are used for war by Denmark. A ship of the line carrying 60 to 120 cannons appears in Europe. Samuel Pepys' diary mentions a machine gun like pistol. The "true" flintlock replaces the snaphance flintlock in Europe by the end of the 17th century. Both China and Japan reject the flintlock and the Mughal Empire only uses it in limited quantities. Gunpowder is used for mining in Europe.
18th century
Major developments: Flintlocks completely displace matchlock firearms in Europe both on land and at sea. Sir William Congreve, 1st Baronet discovers "cylinder powder", gunpowder produced using charcoal in iron cylinders, which is twice as powerful as traditional gunpowder and less likely to spoil. He also invents block trail carriages, the most advanced artillery transport of the time. James Puckle invents a breechloader flintlock capable of firing 63 shots in seven minutes. The Kingdom of Mysore deploys iron cased rockets known as Mysorean rockets.
19th century
Major developments: Sir William Congreve, 2nd Baronet develops the Congreve rockets based on Mysorean rockets and British forces successfully deploy them against Copenhagen. Joshua Shaw invents percussion caps which replace the flintlock trigger mechanism. Claude-Étienne Minié invents the Minié ball, making rifles a viable military firearm, ending the era of smoothbore muskets. Subsequently rifles are deployed in the Crimean War with resounding success. Benjamin Tyler Henry invents the Henry rifle, the first reliable repeating rifle. Richard Jordan Gatling invents the Gatling gun, capable of firing 200 cartridges in a minute. Hiram Maxim invents the Maxim gun, the first single-barreled machine gun. Both China and Europe start using cast iron molds for casting cannons. Alfred Nobel invents dynamite, the first stable explosive stronger than gunpowder. Smokeless powder is invented and replaces the traditional "black powder" in Europe by the end of the century.
20th century
Major developments: Smokeless powder replaces traditional "black powder" across the globe, ending the gunpowder age.
See also
Timeline of the gunpowder age in Japan
Timeline of the gunpowder age in Korea
Timeline of the gunpowder age in South Asia
Timeline of the gunpowder age in Southeast Asia
Citations
References
Hadden, R. Lee. 2005. "Confederate Boys and Peter Monkeys." Armchair General. January 2005. Adapted from a talk given to the Geological Society of America on 25 March 2004.
Schmidtchen, Volker (1977a), "Riesengeschütze des 15. Jahrhunderts. Technische Höchstleistungen ihrer Zeit", Technikgeschichte 44 (2): 153–173 (153–157)
Schmidtchen, Volker (1977b), "Riesengeschütze des 15. Jahrhunderts. Technische Höchstleistungen ihrer Zeit", Technikgeschichte 44 (3): 213–237 (226–228)
.
Historical timelines
Medieval weapons
Warfare of the early modern period
History of chemistry
Alchemy
Ammunition
Gunpowder
History of weapons | Timeline of the gunpowder age | [
"Physics"
] | 1,535 | [
"Wikipedia timelines",
"Spacetime",
"Physical quantities",
"Time"
] |
53,477,203 | https://en.wikipedia.org/wiki/List%20of%20fusor%20examples | The following is a list of fusor examples, examples of the fusor-type nuclear fusion reactor that uses inertial electrostatic confinement
Professional
Fusors have been theoretically studied at multiple institutions, including: Kyoto University, and Kyushu University. Researchers meet annually at the US-Japan Workshop on Inertial Electrostatic Confinement Fusion. The following is a list of machines that were actually built.
Tokyo Institute of Technology has four IEC devices of different shapes: a spherical machine, a cylindrical device, a co-axial double cylinder and a magnetically assisted device.
University of Wisconsin-Madison A group at Wisconsin-Madison has been running a very large, funded, fusor program since 1991.
Turkish Atomic Energy Authority In 2013 this team built a 30 cm fusor at the Saraykoy Nuclear Research and Training center in Turkey. This fusor can reach 85 kV and do deuterium fusion, producing neutrons per second.
University of Illinois Dr. George Miley's team at the fusion studies laboratory has built a ~25 cm fusor which has produced neutrons per second using deuterium gas.
University of Sydney Dr. Joseph Khachan's group in the Department of Physics has built a variety of IEC devices in both positive and negative polarities and spherical and cylindrical geometries.
Atomic Energy Organization of Iran Researchers at Shahid Beheshti University in Iran have built a 60 cm diameter fusor which can produce neutrons per second at 140 kV using deuterium gas.
Los Alamos National Laboratory In the late nineties, researchers purposed and built a fusor-like system for oscillating plasma, inside a fusor. This device is known as the Periodically Oscillating Plasma Sphere or POPS.
Massachusetts Institute of Technology For his doctoral thesis in 2007, Carl Dietrich built a fusor and studied its potential use in spacecraft propulsion. In addition, Tom McGuire did his thesis on fusors with multiple cages and ion guns.
ITT Corporation Hirschs original machine was a 17.8 cm diameter machine with 150 kV voltage drop across it. This machine used ion beams.
Phoenix Nuclear Labs has developed a commercial neutron source based on a fusor, achieving neutrons per second with the deuterium-deuterium fusion reaction.
Amateur
A number of amateurs have built working fusors and detected neutrons. Many fusor enthusiasts connect on forums and message boards online. Below are some examples of working fusors.
Richard Hull Since the late nineties, Richard Hull has built several fusors in his home in Richmond, Virginia. In March 1999, he achieved a neutron rate of neutrons per second. Hull maintains a list of amateurs who have detected neutrons from fusors.
Carl Greninger Founded the Northwest Nuclear Consortium, an organization in Washington state which teaches a class of a dozen high school students nuclear engineering principles using a 60 kV fusor.
Taylor Wilson built a Fusor at 14 years old in 2008.
Matthew Honickman Was a high school student who built a working fusor in his basement in Rochester, New York.
Michael Li In 2003, Michael Li became the youngest person to date to build a fusor, winning second place in the US Intel Science Talent Search winning a $75,000 college scholarship.
Mark Suppes A web designer for Gucci in Brooklyn New York, built a working fusor on a path to building the first amateur Polywell.
Thiago David Olson Built a 40 kV fusor at age 17, in his home in Rochester, Michigan and placed second in the International Science and Engineering Fair in 2007.
Jamie Edwards who fused the atom at 13, at his middle school in England. He received a letter from the Duke of York, was invited on The David Letterman Show and gave a TED talk.
Conrad Farnsworth of Newcastle, Wyoming produced fusion in 2011 at 17 and used this to win a regional and state science fair.
References
See also
Inertial confinement fusion
Nuclear fusion
Fusion power
Neutron sources
Fusion reactors
American inventions | List of fusor examples | [
"Physics",
"Chemistry"
] | 811 | [
"Nuclear fusion",
"Fusion reactors",
"Fusion power",
"Plasma physics"
] |
53,477,645 | https://en.wikipedia.org/wiki/SQL%3A2016 | SQL:2016 or ISO/IEC 9075:2016 (under the general title "Information technology – Database languages – SQL") is the eighth revision of the ISO (1987) and ANSI (1986) standard for the SQL database query language. It was formally adopted in December 2016. The standard consists of 9 parts which are described in some detail in SQL. The next version is SQL:2023.
New features
SQL:2016 introduced 44 new optional features. 22 of them belong to the JSON functionality, ten more are related to polymorphic table functions. The additions to the standard include:
JSON: Functions to create JSON documents, to access parts of JSON documents and to check whether a string contains valid JSON data
Row Pattern Recognition: Matching a sequence of rows against a regular expression pattern
Date and time formatting and parsing
LISTAGG: A function to transform values from a group of rows into a delimited string
Polymorphic table functions: table functions without predefined return type
New data type DECFLOAT
See also
Structured Query Language
References
External links
.
ISO/IEC TR 19075-5:2016: Row Pattern Recognition in SQL
ISO/IEC TR 19075-6:2017: SQL support for JavaScript Object Notation (JSON)
ISO/IEC TR 19075-7:2017: Polymorphic table functions in SQL
Declarative programming languages
Query languages
Computer-related introductions in 2016 | SQL:2016 | [
"Technology"
] | 289 | [
"Computing stubs"
] |
56,275,652 | https://en.wikipedia.org/wiki/R.%20Sankararamakrishnan | Ramasubbu Sankararamakrishnan is an Indian computational biologist, bioinformatician and a professor at the Department of Biological Sciences and Bioengineering of the Indian Institute of Technology, Kanpur. He is known for his computational studies on membrane protein function. The Department of Biotechnology of the Government of India awarded him the National Bioscience Award for Career Development, one of the highest Indian science awards, for his contributions to biosciences in 2008.
Biography
R. Sankararamakrishnan, who completed his early college education at the Madurai Kamaraj University in 1986, did his doctoral studies at the Indian Institute of Science and after obtaining a PhD in 1992, he moved to the UK where he did his post-doctoral research in computational biology at the University of Oxford. He had another stint of post-doctoral work at the University of Illinois, Urbana-Champaign and started his career in 1996 as an instructor (later assistant professor of research) at the Icahn School of Medicine at Mount Sinai. In April 2002, he returned to India to join the Indian Institute of Technology, Kanpur (IITK) as an assistant professor and serves as a professor at the Department of Biological Sciences and Bioengineering (BSBE). Subsequently, he founded the Bioinformatics and Biomolecular Simulation Laboratory at IITK where he hosts several research scholars. He also serves as a resource person for the Centre for Mathematical Biology of the Department of Science and Technology.
Legacy
Sankaramakrishnan's research is focused on mechanism of membrane protein function using computational approaches. He is known to have carried out research on aquaporin genes in plants, Asx turns, molecular dynamic simulations of protein-protein interactions, GPCR peptide hormones as well as nonAUG start codons and AUG codons. His studies have been documented by way of a number of articles and ResearchGate, an online repository of scientific articles has listed 98 of them. Besides, he has also contributed chapters to books published by others and his articles have drawn many citations. He is the co-author of MIPModDB, a database of structure models of Major intrinsic proteins. He has also delivered invited or keynote speeches at various national and international seminars.
Sankararamakrishnan is a member of the National Network for Mathematical and Computational Biology, an agency funded by the Science and Engineering Research Board of the Government of India for promoting scientific research and advanced training in the discipline. He is also a life member of the National Academy of Sciences, India, one of the three major Indian science academies.
Awards and honors
The Department of Biotechnology of the Government of India awarded him the National Bioscience Award for Career Development, one of the highest Indian science awards in 2008. He has also held the Joy Gill Chair Professorship for Young Faculty and the U.S.V. Chair Professorship of the Indian Institute of Technology, Kanpur during 2007-2010 and 2011-2014 respectively.
Selected bibliography
Chapters
Articles
See also
Kozak consensus sequence
Molecular dynamics
Notes
References
Further reading
External links
N-BIOS Prize recipients
Living people
Indian computational chemists
Computational biology
Scientists from Madhya Pradesh
Madurai Kamaraj University alumni
Indian Institute of Science alumni
Icahn School of Medicine at Mount Sinai faculty
Alumni of the University of Oxford
University of Illinois Urbana-Champaign alumni
Academic staff of IIT Kanpur
Indian bioinformaticians
Year of birth missing (living people) | R. Sankararamakrishnan | [
"Biology"
] | 694 | [
"Computational biology"
] |
56,275,884 | https://en.wikipedia.org/wiki/Data-driven%20control%20system | Data-driven control systems are a broad family of control systems, in which the identification of the process model and/or the design of the controller are based entirely on experimental data collected from the plant.
In many control applications, trying to write a mathematical model of the plant is considered a hard task, requiring efforts and time to the process and control engineers. This problem is overcome by data-driven methods, which fit a system model to the experimental data collected, choosing it in a specific models class. The control engineer can then exploit this model to design a proper controller for the system. However, it is still difficult to find a simple yet reliable model for a physical system, that includes only those dynamics of the system that are of interest for the control specifications. The direct data-driven methods allow to tune a controller, belonging to a given class, without the need of an identified model of the system. In this way, one can also simply weight process dynamics of interest inside the control cost function, and exclude those dynamics that are out of interest.
Overview
The standard approach to control systems design is organized in two-steps:
Model identification aims at estimating a nominal model of the system , where is the unit-delay operator (for discrete-time transfer functions representation) and is the vector of parameters of identified on a set of data. Then, validation consists in constructing the uncertainty set that contains the true system at a certain probability level.
Controller design aims at finding a controller achieving closed-loop stability and meeting the required performance with .
Typical objectives of system identification are to have as close as possible to , and to have as small as possible. However, from an identification for control perspective, what really matters is the performance achieved by the controller, not the intrinsic quality of the model.
One way to deal with uncertainty is to design a controller that has an acceptable performance with all models in , including . This is the main idea behind robust control design procedure, that aims at building frequency domain uncertainty descriptions of the process. However, being based on worst-case assumptions rather than on the idea of averaging out the noise, this approach typically leads to conservative uncertainty sets. Rather, data-driven techniques deal with uncertainty by working on experimental data, and avoiding excessive conservativism.
In the following, the main classifications of data-driven control systems are presented.
Indirect and direct methods
There are many methods available to control the systems.
The fundamental distinction is between indirect and direct controller design methods. The former group of techniques is still retaining the standard two-step approach, i.e. first a model is identified, then a controller is tuned based on such model. The main issue in doing so is that the controller is computed from the estimated model (according to the certainty equivalence principle), but in practice . To overcome this problem, the idea behind the latter group of techniques is to map the experimental data directly onto the controller, without any model to be identified in between.
Iterative and noniterative methods
Another important distinction is between iterative and noniterative (or one-shot) methods. In the former group, repeated iterations are needed to estimate the controller parameters, during which the optimization problem is performed based on the results of the previous iteration, and the estimation is expected to become more and more accurate at each iteration. This approach is also prone to on-line implementations (see below). In the latter group, the (optimal) controller parametrization is provided with a single optimization problem. This is particularly important for those systems in which iterations or repetitions of data collection experiments are limited or even not allowed (for example, due to economic aspects). In such cases, one should select a design technique capable of delivering a controller on a single data set. This approach is often implemented off-line (see below).
On-line and off-line methods
Since, on practical industrial applications, open-loop or closed-loop data are often available continuously, on-line data-driven techniques use those data to improve the quality of the identified model and/or the performance of the controller each time new information is collected on the plant. Instead, off-line approaches work on batch of data, which may be collected only once, or multiple times at a regular (but rather long) interval of time.
Iterative feedback tuning
The iterative feedback tuning (IFT) method was introduced in 1994, starting from the observation that, in identification for control, each iteration is based on the (wrong) certainty equivalence principle.
IFT is a model-free technique for the direct iterative optimization of the parameters of a fixed-order controller; such parameters can be successively updated using information coming from standard (closed-loop) system operation.
Let be a desired output to the reference signal ; the error between the achieved and desired response is . The control design objective can be formulated as the minimization of the objective function:
Given the objective function to minimize, the quasi-Newton method can be applied, i.e. a gradient-based minimization using a gradient search of the type:
The value is the step size, is an appropriate positive definite matrix and is an approximation of the gradient; the true value of the gradient is given by the following:
The value of is obtained through the following three-step methodology:
Normal Experiment: Perform an experiment on the closed loop system with as controller and as reference; collect N measurements of the output , denoted as .
Gradient Experiment: Perform an experiment on the closed loop system with as controller and 0 as reference ; inject the signal such that it is summed to the control variable output by , going as input into the plant. Collect the output, denoted as .
Take the following as gradient approximation: .
A crucial factor for the convergence speed of the algorithm is the choice of ; when is small, a good choice is the approximation given by the Gauss–Newton direction:
Noniterative correlation-based tuning
Noniterative correlation-based tuning (nCbT) is a noniterative method for data-driven tuning of a fixed-structure controller. It provides a one-shot method to directly synthesize a controller based on a single dataset.
Suppose that denotes an unknown LTI stable SISO plant, a user-defined reference model and a user-defined weighting function. An LTI fixed-order controller is indicated as , where , and is a vector of LTI basis functions. Finally, is an ideal LTI controller of any structure, guaranteeing a closed-loop function when applied to .
The goal is to minimize the following objective function:
is a convex approximation of the objective function obtained from a model reference problem, supposing that .
When is stable and minimum-phase, the approximated model reference problem is equivalent to the minimization of the norm of in the scheme in figure.
The input signal is supposed to be a persistently exciting input signal and to be generated by a stable data-generation mechanism. The two signals are thus uncorrelated in an open-loop experiment; hence, the ideal error is uncorrelated with . The control objective thus consists in finding such that and are uncorrelated.
The vector of instrumental variables is defined as:
where is large enough and , where is an appropriate filter.
The correlation function is:
and the optimization problem becomes:
Denoting with the spectrum of , it can be demonstrated that, under some assumptions, if is selected as:
then, the following holds:
Stability constraint
There is no guarantee that the controller that minimizes is stable. Instability may occur in the following cases:
If is non-minimum phase, may lead to cancellations in the right-half complex plane.
If (even if stabilizing) is not achievable, may not be stabilizing.
Due to measurement noise, even if is stabilizing, data-estimated may not be so.
Consider a stabilizing controller and the closed loop transfer function .
Define:
Theorem
The controller stabilizes the plant if
is stable
s.t.
Condition 1. is enforced when:
is stable
contains an integrator (it is canceled).
The model reference design with stability constraint becomes:
A convex data-driven estimation of can be obtained through the discrete Fourier transform.
Define the following:
For stable minimum phase plants, the following convex data-driven optimization problem is given:
Virtual reference feedback tuning
Virtual Reference Feedback Tuning (VRFT) is a noniterative method for data-driven tuning of a fixed-structure controller. It provides a one-shot method to directly synthesize a controller based on a single dataset.
VRFT was first proposed in and then extended to LPV systems. VRFT also builds on ideas given in as .
The main idea is to define a desired closed loop model and to use its inverse dynamics to obtain a virtual reference from the measured output signal .
The virtual signals are and
The optimal controller is obtained from noiseless data by solving the following optimization problem:
where the optimization function is given as follows:
See also
Automation
Artificial intelligence
References
An Introduction to Data-Driven Control Systems
Ali Khaki-Sedigh
ISBN: 978-1-394-19642-5 November 2023 Wiley-IEEE Press 384 Pages
External links
VRFT toolbox for MATLAB
Dynamical systems
Control theory
Control engineering
Computational mathematics
Robotics engineering | Data-driven control system | [
"Physics",
"Mathematics",
"Technology",
"Engineering"
] | 1,894 | [
"Computer engineering",
"Robotics engineering",
"Applied mathematics",
"Control theory",
"Computational mathematics",
"Control engineering",
"Mechanics",
"Dynamical systems"
] |
56,275,958 | https://en.wikipedia.org/wiki/Bharat%20Bhushan%20%28academic%29 | Bharat Bhushan is an American engineer. He is an Ohio Eminent Scholar and the Howard D. Winbigler Professor at Ohio State University.
Education
Bhushan graduated with a BE in mechanical engineering from the Birla Institute of Technology and Science, Pilani in 1970, an MS in mechanical engineering from the Massachusetts Institute of Technology in 1971, and an MS in mechanics from the University of Colorado, Boulder (CU) in 1973. He received his PhD from CU in 1979. He also has an MBA in management from the Rensselaer Polytechnic Institute (1980).
In addition to five earned college degrees, he has also received five honorary doctorate degrees: in 1990 from the University of Trondheim; in 1996 from the Warsaw University of Technology; in 2000 from the Metal-Polymer Research Institute of the National Academy of Sciences of Belarus; in 2011 from the University of Kragujevac, and in 2019 from University of Tyumen, Russia.
Research
Bhushan's research interests include nanotribology, nanomechanics, scanning probe microscopy, biotechnology, nanotechnology, biomimetics, science and public policy. He has authored or co-authored ten books, more than 900 scientific papers, and holds more than 25 US and foreign patents. He is one of 1500 Google Scholar's ‘Highly Cited Researchers in All Fields’, with a ‘h index’ of 130, and one of Scopus 440 scientists for career-long citation impact across all fields worldwide. He is the Fourth Highly Cited Researcher in Mechanical Engineering and an ISI Highly Cited Researcher in Materials Science and in the Cross-field Category. Among various fellowships, in 1998 and 2007, he received the Alexander von Humboldt Research Prize for Senior Scientists, in 1999, he received the Fulbright Senior Scholar Award, and in 2002 and 2007, he received Max Planck Foundation Research Award for Outstanding Foreign Scientists, He received the International Award from the Society of Tribologists and Lubrication Engineers. In 2015, he received the Institution of Chemical Engineers(UK) Global Award. In 2020, he received the Mayo D. Hersey Award from the American Society of Mechanical Engineers and the Tribology Gold Medal from the International Tribology Council.
References
External links
Nanoprobe Laboratory at OSU
20th-century American engineers
21st-century American engineers
American mechanical engineers
American nanotechnologists
Tribologists
Ohio State University faculty
Living people
American people of Indian descent
Year of birth missing (living people) | Bharat Bhushan (academic) | [
"Materials_science"
] | 501 | [
"Tribology",
"Tribologists"
] |
56,276,347 | https://en.wikipedia.org/wiki/Scent%20rubbing | Scent rubbing is a behavior where a mammal rubs its body against an object in their environment, sometimes in ones covered with strongly odored substances. It is typically shown in carnivores, although many mammals exhibit this behavior. Lowering shoulders, collapsing the forelegs, pushing forward and rubbing the chin, temples, neck, or back is how this act is performed. A variety of different odors can elicit this behavior including feces, vomit, fresh or decaying meat, insecticide, urine, repellent, ashes, human food and so on. Scent rubbing can be produced by an animal smelling novel odors, which include manufactured smells such as perfume or motor oil and carnivore smells including feces and food smells.
Scent rubbing is often performed with scent marking and self-anointing, and is typically used by animals to scent mark an object in their surroundings. This marking can be used as a means of communication between species. Many different species of felids, monkeys, bears, wolves and marmots have primarily been used to study scent rubbing in carnivores. Differences in gender and age exist for scent rubbing, with adults and males performing the behavior more frequently than juveniles and females in many species.
Species
Felidae
Many carnivorous felids scent rub. Felids are able to discriminate between similar smelling odors using the vomeronasal organ, which is important for eliciting scent rubbing. The rubbing behavior is often performed as a means of scent-marking.
Domestic cat
Domestic cats display scent rubbing. The cheeks, abdomen, paws, above tail and around the anus contain organs that produce scent. When a cat is comfortable with their surroundings and environment, they release the feline facial pheromone during facial rubbing in order to leave this pheromone on the objects around them. Cats scent rub against objects as a means of marking by releasing pheromones with glandular secretions, and information about the animal's age, sex, and identity can be obtained from these secretions.
Domestic cats will more frequently rub against an object that is new to their environment. When an object is induced with the scent of another animal it causes an increase in rubbing as it contains sensory properties that are not familiar to the cat. When a cat is presented with an object treated with scent gland secretions from both a rat and snake, the cat will forcefully scent rub its head against it. Mutual face rubbing behavior between cats in groups and cats rubbing against their owners may be a form of social bonding. During rubbing against humans, cats tend to use the temporal gland area which consists of the cheek, between the eye and the ear.
Leopard
Kalahari leopards use trees in their environment to scent rub. When the backs and flanks are rubbed against trees it is most often related to itching rather than scent rubbing, but when rubbing to scent mark is used it is mostly demonstrated by males when mating. It is suggested that this rubbing behavior is a form of chemical communication regarding female attention.
Bears
Bears rub against the ground, trees and rocks in order to scent mark. This is the most frequent way that bears mark their surroundings. Black bears rub their cheeks, back, neck and head against trees in a bipedal stance. This act is noted most often during the breeding season for grizzly and black bears as a form of communication. The behavioral aspect of scent rubbing is shown during interspecific interactions between these bears, as black bears are found to decrease their tree rubbing once a grizzly has already done so. The Andean bear scent rubs against trees at marking sites by rubbing its neck, shoulders, flanks or back. Sometimes this species marks the tree with its claws or urinates while rubbing. The behavior in this species is thought to be linked to intraspecific communication. This communication lets other bears know whose territory it is.
New World monkeys
The rubbing behaviors of the Southern brown howler monkeys are linked to scent marking. Throat (facial and neck), anal, dorsal, chest and chin rubbing has been observed in Alouatta and is mostly performed while sitting. Like felids, howler monkeys use their vomeronasal sensory organs to distinguish pheromones. Dominant howlers of both male and female genders scent rub and mark more than subordinate conspecifics. Anogenital rubbing in monkeys is associated with cleaning after defecation and urination and also deposits the animals scent for other species to notice.
Black-handed spider monkeys are another Atelidae species which display fur rubbing against the leaves of Rutaceae plants. Their scent rubbing behaviour resembles those shown by white-faced capuchins, often done by many individuals simultaneously, creating an interaction among their population and may function in scent marking and olfactory communication. Woolly monkeys also show scent rubbing in the form of chest rubbing that suggests the behaviour has a reproductive function. The reasoning for chest rubbing in woolly monkeys is similar to the throat rubbing displayed by howler monkeys during mating season. Rubbing behaviour in woolly monkeys has also been linked to dominance and social communication.
Gray wolf
Gray wolves scent rub to a large variety of odors including urine, perfumes, repellant, ashes, human handled objects, food, and resting sites. They scent rub intensively to manufactured smells such as motor oil and carnivore scents such as feces of other animals including black bear and cougars. The reason behind scent rubbing in wolves is unknown, but it is suggested that they use it to remember odors experienced in their environment, whether new or familiar.
Marmot
Marmots slowly rub their faces from mouth to ears on objects repeatedly as a form of scent rubbing called cheek rubbing. This behavior is common, and the objects are typically stones, rocks and the ground around burrows. They conduct this behavior to scent mark, and when interrupted fights can occur. Marmots scent rub on new objects within their home environment.
Communication
Scent rubbing can be used as a form of communication between many terrestrial mammals. This method is used to send messages, find mates and to keep away from areas where others have foraged. Odours produced by sweat glands, urine, feces and vaginal secretions often induce this behavior, which is prominent in carnivore species. Scent rubbing by males in many species is related to intrasexual communication and social interaction, such as the social status the animal holds in that population. Carnivores often scent rub as a mechanism of olfactory communication in which they release chemical odours to increase odds of being detected by conspecifics.
Spider monkeys rub saliva onto their sternal region and then rub this area against a tree, which may serve as a form of olfactory communication as they often use their apocrine glands, located in the sternal area, for this communication. Rubbing behavior displayed through cheek rubbing can reveal dominance in a population, with subordinate individuals doing this less than dominant ones. Scent rubbing also allows animals to gather scent from their surroundings onto themselves. Gray foxes have been found to cheek rub fresh puma scrapes in order to acquire the scent and mask their own, deterring predation by other animals. This shows that scent rubbing has an interspecific scent marking function.
Odours that induce rubbing
Both strong naturally occurring and artificial substances can cause mammals to scent rub. Strong smelling substances include rotting meat, fresh meat, vomit, faeces, food and the intestinal contents of other animals. Artificial substances that induce this behaviour include engine oil, perfume and insecticide. When an animal encounters an object with a novel or familiar smell it can elicit rubbing various body parts against this object.
Sex and age differences
Sex
The scent rubbing behavior has been observed more frequently in males than females for many species. Certain male domestic cats, bears, monkeys and leopards are shown to scent rub more than their female conspecifics. There is an increase of scent rubbing during breeding season for black bears, but this is done predominantly by males. Body rubbing as a means of scent marking is done more often by male pumas. In species of spider monkey, adult males perform fur rubbing more often than females.
Age
Scent rubbing in cats is performed by adult animals more often than juveniles, indicating that the behaviour is used as a means of marking territory or of expressing their status. Adult marmots display a form of scent rubbing called cheek rubbing more than young members of the species. Mature pumas spent a significantly longer time body rubbing than immature pumas, which is related to communication behaviours developing with age, mature females did not visit their community scrapes as often. Only sexually mature woolly monkeys exhibit chest rubbing, which suggests that this scent rubbing behaviour reproductive function.
References
Mammal behavior | Scent rubbing | [
"Biology"
] | 1,778 | [
"Behavior by type of animal",
"Behavior",
"Mammal behavior"
] |
56,276,609 | https://en.wikipedia.org/wiki/Bj%C3%B6rk%C3%A9n%20Prize | The Björkén Prize (Swedish: Björkénska priset) is a scientific award given by Uppsala University. It is awarded for outstanding research in science and the theoretical branches of medicine. The prize was established in 1893 from a donation given by university lecturer (1833–1893). Björkén was a physician and medical assistant professor in surgery and obstetrics at Uppsala. The prize was first awarded in 1902 on the day of his death.
The Björkén Prize is alternately awarded for achievement in four different fields:
Botany, zoology, and landscape planning
Chemistry, mineralogy, metallurgy, and geology
Physics, mechanics, and engineering science
Theoretical disciplines of medical sciences
Winners
References
External links
The Björkén Prize webpage
Uppsala University
Swedish awards
Awards established in 1902
Swedish science and technology awards | Björkén Prize | [
"Technology"
] | 167 | [
"Science and technology awards",
"Science award stubs"
] |
56,276,862 | https://en.wikipedia.org/wiki/Venoms%20in%20medicine | Venom in medicine is the medicinal use of venoms for therapeutic benefit in treating diseases.
Venom is any poisonous compound secreted by an animal intended to harm or disable another. When an organism produces a venom, its final form may contain hundreds of different bioactive elements that interact with each other inevitably producing its toxic effects. This mixture of ingredients includes various proteins, peptides, and non-peptidic small molecules. The active components of these venoms are isolated, purified, and screened in assays. These may be either phenotypic assays to identify component that may have desirable therapeutic properties (forward pharmacology) or target directed assays to identify their biological target and mechanism of action (reverse pharmacology).
Background
Venoms are naturally occurring substances that organisms evolved to deploy against other organisms, in defense or attack. They are often mixtures of proteins that act together or singly to attack their specific targets within the organism against which they are used, generally with high specificity and generally easily accessible through the vascular system. This has made venoms a subject of study for people who work in drug discovery. With developments in omic technologies (proteomics, genomics, etc.), researchers in this field became able to identify genes that produce certain elements in an animal's venom, as well as protein domains that have been used as building blocks across many species. In conjunction with methods of separation and purification of compounds, scientists are able to study each individual compound that exists within a venom "concoction", looking for compounds to serve as drug leads or other use. Each venomous organism produces thousands of different proteins giving access to millions of different molecules that still have potential uses. In addition, nature is continuously evolving; as prey develop resistance to these venoms, the predators also evolve as well, creating novel toxins that can continue to act upon its respective prey.
History
The earliest known use of venom in medicine dates back to 380 B.C. in ancient Greece. Aristotle's "Historia Animalium", describes how venom can be used in the production of antidotes for the venom. During the height of the Roman empire, there is evidence of venom being added into medicine used to treat smallpox, leprosy, fever, and wounds. Despite this, early uses of venom were primarily involved in the process of making antidotes. This use of venom continued into the Middle Ages and well into the 19th century. The first modern study of venom in a medical light occurred in the late 19th century. A scientist, Albert Calmatte, injected animals with small amounts of venom, using their blood as the antidote.
Marketed drugs
Captopril
Captopril emulates the function of the toxin found in Brazilian pit viper (Bothrops jararaca) venom and is generally accepted as the first venom "success" story. Captopril is an ACE inhibitor (angiotensin-converting enzyme) that was approved by the FDA approved in April 1981. It lowers blood pressure by inhibiting the production of angiotensin II which acts in a pathway that leads to vasoconstriction which raises blood pressure. After the creation of this drug, many analogues (enalapril, lisinopril, perindopril, ramipril, etc.) were produced.
Ziconotide
Ziconotide is a synthetically made version of the ω-conotoxin made by the cone snail, that is used to treat severe pain and is delivered as an infusion into the cerebrospinal fluid using an intrathecal pump system. Ziconitide acts presynaptically on N-type calcium channels, blocking the receptors of this channel with high selectivity and affinity,
Eptifibatide
Eptifibatide was modeled after a component in southeastern pygmy rattlesnake venom and is used in anticoagulation therapies in an effort to reduce the risk of heart attacks; it is used in only severe cases because of the possible side effect of thrombocytopenia, a condition where platelets are unable to aggregate at all. Eptifibatide binds reversibly to platelets reducing the risk of thrombosis. It is an antagonist of glycoprotein IIb/IIIa.
Exenatide
Exenatide is a 39-amino-acid peptide that is a synthetic version of exendin-4, a hormone found in the saliva of the Gila monster. It is used to treat Type II Diabetes as an adjunct to insulin and other drugs. It is GLP-1 receptor agonist that was first isolated by John Eng in 1992 while working at the Veterans Administration Medical Center in the Bronx, New York.
Batroxobin
Batroxobin, is a serine protease found in snake venom produced by Bothrops atrox and Bothrops moojeni, venomous species of pit viper found east of the Andes in South America. It cleaves fibrinogen, similarly to thrombin. Batroxobin from B atrox is used as a drug called "Reptilase" that is used to stop bleeding, while batroxobin from B moojeni is a drug called "Defibrase", used to break up blood clots. It is also used in a system called "Vivostat", where a person's blood is taken just before surgery and exposed to batroxobin; the resulting clots are then harvested, and then dissolved, forming a fibrin glue that is then used on the person during the surgery.
References
Further reading
Drug discovery
Medicinal chemistry
Pharmacology
Toxins | Venoms in medicine | [
"Chemistry",
"Biology",
"Environmental_science"
] | 1,174 | [
"Pharmacology",
"Toxicology",
"Life sciences industry",
"Drug discovery",
"nan",
"Medicinal chemistry",
"Biochemistry",
"Toxins"
] |
56,277,564 | https://en.wikipedia.org/wiki/Gradient%20echo | Gradient echo is a magnetic resonance imaging (MRI) sequence that has wide variety of applications, from magnetic resonance angiography to perfusion MRI and diffusion MRI. Rapid imaging acquisition allows it to be applied to 2D and 3D MRI imaging. Gradient echo uses magnetic gradients to generate a signal, instead of using 180 degrees radiofrequency pulse like spin echo; thus leading to faster image acquisition time.
Mechanism
Unlike spin-echo sequence, a gradient echo sequence does not use a 180 degrees RF pulse to make the spins of particles coherent. Instead, the gradient echo uses magnetic gradients to manipulate the spins, allowing the spins to dephase and rephase when required. After an excitation pulse (usually less than 90 degrees), the spins are dephased after a period of time (due to free induction decay) and also by applying a reversed magnetic gradient to decay the spins. No signal is produced because the spins are not coherent. When the spins are rephased via a magnetic gradient, they become coherent, and thus signal (or "echo") is generated to form images. Unlike spin echo, gradient echo does not need to wait for transverse magnetisation to decay completely before initiating another sequence, thus it requires very short repetition times (TR), and therefore to acquire images in a short time.
After echo is formed, some transverse magnetisations remains because of short TR. Manipulating gradients during this time will produce images with different contrast. There are three main methods of manipulating contrast at this stage, namely steady-state free-precession (SSFP) that does not spoil the remaining transverse magnetisation, but attempts to recover them in subsequent RF pulses (thus producing T2-weighted images); the sequence with spoiler gradient that averages the transverse magnetisations in subsequent RF pulses by rotating residual transverse magnetisation into longitudinal plane and longitudinal magnetisation into transverse planes (thus producing mixed T1 and T2-weighted images), and RF spoiler that vary the phases of RF pulse to eliminates the transverse magnetisation, thus producing pure T1-weighted images.
Gradient echo uses a flip angle smaller than 90 degrees, thus longitudinal magnetisation is not eliminated while flipping the spins. The larger the flip angle, the higher the T1 weighing of the tissue because more longitudinal magnetisation most recover to produce a difference in signals between the tissues.
Steady-state free precession
Steady-state free precession imaging (SSFP) or balanced SSFP is an MRI technique which uses short repetition times (TR) and low flip angles (about 10 degrees) to achieve steady state of longitudinal magnetizations as the magnetizations does not decay completely nor achieving full T1 relaxation. While spoiled gradient-echo sequences refer to a steady state of the longitudinal magnetization only, SSFP gradient-echo sequences include transverse coherences (magnetizations) from overlapping multi-order spin echoes and stimulated echoes. This is usually accomplished by refocusing the phase-encoding gradient in each repetition interval in order to keep the phase integral (or gradient moment) constant. Fully balanced SSFP MRI sequences achieve a phase of zero by refocusing all imaging gradients.
MP-RAGE (magnetization-prepared rapid acquisition with gradient echo) improves images of multiple sclerosis cortical lesions.
Spoiling
At the end of the reading, the residual transverse magnetization can be terminated (through the application of suitable gradients and the excitation through pulses with a variable phase radiofrequency) or maintained.
In the first case there is a spoiled sequence, such as the fast low-angle shot MRI (FLASH MRI) sequence, while in the second case there are steady-state free precession imaging (SSFP) sequences.
In-phase and out-of-phase
In-phase (IP) and out-of-phase (OOP) sequences correspond to paired gradient echo sequences using the same repetition time (TR) but with two different echo times (TE). This can detect even microscopic amounts of fat, which has a drop in signal on OOP compared to IP. Among renal tumors that do not show macroscopic fat, such a signal drop is seen in 80% of the clear cell type of renal cell carcinoma as well as in minimal fat angiomyolipoma.
Effective T2 (T2* or "T2-star")
T2*-weighted imaging can be created as a postexcitation refocused gradient echo sequence with small flip angle. The sequence of a GRE T2*WI requires high uniformity of the magnetic field.
Commercial names of gradient echo sequences
VIBE (volumetric interpolated breath-hold examination) is an MRI sequence that produces T1-weighted gradient echo images in three-dimensions (3D). Apart from lower fluid signal intensity than a typical T1-weighted image, other appearances of VIBE images is similar to a typical T1-weighted image. Since its acquisition is only 30 seconds, suitable for breath-holding, it is used in breast and abdominal imaging to obtain high-resolution images minimising respiratory movement artifacts. VIBE images have low contrast in soft tissues and cartilage but have high contrast between the bony cortex and bone marrow. Bony lesions such as callus and fibrous tissue can also be readily distinguished from surrounding cortical bone because high contrast between the bone lesions and the bony cortex.
References
Magnetic resonance imaging
Nuclear magnetic resonance
Quantum mechanics | Gradient echo | [
"Physics",
"Chemistry"
] | 1,108 | [
"Nuclear magnetic resonance",
"Magnetic resonance imaging",
"Theoretical physics",
"Quantum mechanics",
"Nuclear physics"
] |
56,278,061 | https://en.wikipedia.org/wiki/Wash%20copper | A wash copper, copper boiler or simply copper is a wash house boiler, generally made of galvanised iron, though the best sorts are made of copper. In the inter-war years they came in two types. The first is built into a brickwork furnace and was found in older houses. The second was the free-standing or portable type, it had an enamelled metal exterior that supported the inner can or copper. The bottom part was adapted to hold a gas burner, a high pressure oil or an ordinary wood or coal fire. Superior models could have a drawing-off tap, and a steam-escape pipe that led into the flue.
It was used for domestic laundry. Linen and cotton were placed in the copper and were boiled to whiten them. Clothes were agitated within the copper with a washing dolly, a vertical stick with either a metal cone or short wooden legs on it. After washing, the laundry was lifted out of the boiling water using the washing dolly or a similar device, and placed on a strainer resting on a laundry tub or similar container to capture the wash water and begin the drying and cooling process. The laundry was then dried with a mangle and then line-dried.
Coppers could also be used in cooking, used to boil puddings such as a traditional Christmas pudding.
Meticulous care was taken to avoid rust, and grease. In cases of the latter it could be cleaned with paraffin or soft soap. Water was always put in the copper before it was lit. In the case of solid fuel, a small shovel of hot coals would be brought from the main kitchen fire and coke shovelled on top.
See also
Russian stove
Kamado (Japanese)
Furo
Agungi/Buttumak (Korean)
References
External links
Laundry washing equipment
Fire
Heating | Wash copper | [
"Chemistry"
] | 367 | [
"Combustion",
"Fire"
] |
56,278,327 | https://en.wikipedia.org/wiki/Margaret%20Douie%20Dougal | Margaret Douie Dougal ( – 1938, née Robertson, later Chaplin) was a British chemical publication indexer for fifteen years (1885–1909) for the Chemical Society. Dougal contributed to the compilation of volumes i-iii of A Collective Index of the Transactions, Proceedings and Abstracts of the Chemical Society. The then president of the Chemical society, Sir James Dewar, congratulated Dougal for her work as "an example of thoroughness and accuracy to her successors." The collected decennial indices were also prepared by Dougal; at the 1906 Annual Meeting of the Chemical Society it was noted that the Council "had pleasure in expressing the high appreciation of the ceaseless energy displayed by the indexer, Mrs. Margaret Dougal, on the completion of this valuable work."
Under Thomas Edward Thorpe, Dougal conducted inorganic chemistry research of mixed salts of chromium by testing their compositions. Research she conducted also provided insight on the stress and fracturing behavior of iron in Scottish craftsmanship and manufacturing in 1892.
Dougal was born Margaret Douie Robertson in Singapore in , the daughter of J.H. Robertson M.D.. She married William Dougal and, after his death, married Arnold Chaplin M.D. F.R.C.P. on 29 July 1909. She died in London on 9 November 1938 at the age of 79.
References
19th-century British chemists
19th-century British women scientists
British chemists
British women chemists
Inorganic chemists
1850s births
1938 deaths
Date of birth missing
Place of birth missing
Place of death missing
Indexers | Margaret Douie Dougal | [
"Chemistry"
] | 320 | [
"British inorganic chemists",
"Inorganic chemists"
] |
56,278,630 | https://en.wikipedia.org/wiki/Electrofusion%20welding | Electrofusion welding is a form of resistive implant welding used to join pipes. A fitting with implanted metal coils is placed around two ends of pipes to be joined, and current is passed through the coils. Resistive heating of the coils melts small amounts of the pipe and fitting, and upon solidification, a joint is formed. It is most commonly used to join polyethylene (PE) and polypropylene (PP) pipes. Electrofusion welding is the most common welding technique for joining PE pipes. Because of the consistency of the electrofusion welding process in creating strong joints, it is commonly employed for the construction and repair of gas-carrying pipelines. The development of the joint strength is affected by several process parameters, and a consistent joining procedure is necessary for the creation of strong joints.
Advantages and disadvantages
Advantages of electrofusion welding:
Simple process capable of producing consistent joints
Process is entirely contained, reducing the risk of joint contamination
Process allows repair without the need to remove pipes
Disadvantages of electrofusion welding:
A special sleeve is required, so it is more expensive than other pipe joining methods such as hot plate joining
Implanted coils make recycling of parts more difficult
Equipment
Electrofusion welds are performed by attaching a controlled power supply to the electrofusion fitting. There are typically two modes of operation.
Constant voltage
Constant current
Constant voltage is typically used for high pressure pipelines such as mains gas and water. Fittings are fitted with a barcode specified to an ISO standard.
Typically fittings will be welded at 39.5v, but manufacturers can choose voltages in whole numbers from 8 to 48v. The welding time is specified on the label in seconds or minutes
Accessories
Electrofusion welding employs fittings that are placed around the joint to be welded. Metal coils are implanted into the fittings, and electric current is run through the coils to generate heat and melt part of the pipes, forming a joint upon solidification. There are two possible fittings used in electrofusion welding: couplers and tapping tees (saddles). Coupler fittings contain two separate regions of coils, creating two distinct fusion zones during welding. The inner diameter of the coupler is typically slightly larger than the outer diameter of the pipes. This is to increase the ease of assembly in the field and allows for minor inconsistencies in pipe diameter. Proper insertion of the pipes in the coupler is critical for the creation of a strong joint. Incorrect placement of the coupler can cause the coils to move and lead to the extrusion of molten polymer material from the joint, reducing the joint's strength. Tapping tees, or saddles, are less common but operate under the same principles as a coupler. They require clamping to ensure a proper fit up with the pipes.
Fitting installation
Installation of couplers and tapping tee fittings require slightly different procedures. Common installation steps for each are given below.
Couplers
Wash pipe ends to create clean surfaces for joining
Square pipe ends to facilitate optimal fit-up
Clean area where coupler will be placed with isopropyl alcohol
Mark the pipes slightly beyond half the length of the coupler, to indicate where scraping will take place in later steps
Mark the area to be scraped
Scrape pipe in marked areas to remove surface layer, allowing clean pipe material to contact the coupler
Examine scraped area thoroughly, making sure that fresh pipe material is exposed throughout area
Insert pipe ends into coupling to appropriate depth
Secure coupler using clamp
Connect fitting to control box using electrical leads
Apply fusion cycle
Allow joint to be undisturbed for the entire prescribed cooling time
Pressure test pipe
Back fill pipe with appropriate contents
Begin service
Tapping tee
Wash pipe area to be joined to create clean surfaces for joining
Clean area where tapping tee will be placed with isopropyl alcohol
Mark the pipes slightly beyond the edges of the tapping tee location
Scrape pipe in marked areas to remove surface layer, allowing clean pipe material to contact the tapping tee
Examine scraped area thoroughly, making sure that fresh pipe material is exposed throughout area
Place tapping tee onto joint
Secure tapping tee using clamp
Connect fitting control box using electrical leads
Apply fusion cycle
Allow joint to be undisturbed for the entire prescribed cooling time
Pressure test pipe
Back fill pipe with appropriate contents
Begin service
Power requirements
Electrofusion welding requires electrical current to be passed through the coils implanted in the fittings. Since the electrical energy input is an excellent indicator of the joint strength that develops during fusion, it is necessary to have consistent electrical power input. Energy input during the joining process is typically measured by controlling the time it takes for the current to pass through the fitting. However, energy input can also be monitored by controlling overall temperature, molten polymer temperature, or molten polymer pressure.
A control box takes electrical power from a generator and converts it into an appropriate voltage and current for electrofusion joining. This provides consistent energy input for each application. The most common input voltage for electrofusion welding fittings is 39.5V, as it provides the best results without risking operator safety. The current is input as an alternating current (AC) waveform.
Welding process
Stages during welding
Electrofusion welding is characterized by four distinct stages that occur during the welding process:
Incubation period
Joint formation and consolidation
Plateau region
Cooling period
During the incubation period, heat is introduced into the joint as current is passed through the coil. Although there is no joint strength at this point, the polymer expands and the joint gap is filled. During joint formation and consolidation, melting begins. Melt pressure has begun to build, and the majority of the joint's strength is developed during this stage. The strength increase is due primarily to the constraint of the increasing molten material by the cold zones in the surrounding fitting. The plateau region signals the stabilization of the joint strength. Despite this, the heat of the joint is still increasing with time during this stage. The cooling period occurs after current is no longer applied to the coils. The molten polymer material solidifies and forms the joint.
Current during welding
Most electrofusion welding power supplies are constant voltage machines. Constant current machines would provide more consistent energy input due to the smaller fluctuations in current applied to the coils during welding. However, this additional consistency is generally not worth the higher cost of these machines. When a constant voltage machine is used, the value of the applied current slowly decreases throughout the welding process. This effect is due to the increasing resistance of the coils as energy is applied. As heat is generated in the coils, their temperature increases, leading to a higher electrical resistance in the coils. This increased electrical resistance causes a smaller current to be generated from the same voltage level as the process progresses. The extent of the current decrease is determined by the material used for the coil. The energy input per unit area can be calculated and used to monitor the process. Typical values for this range from 2–13 J/mm2, with a value of 3.9 J/mm2 having been found to produce the strongest joints.
Temperature during welding
Large temperature gradients exist in the electrofusion joint during the fusion cycle. The low thermal conductivity of polymers is the main cause of these large gradients. Recent efforts to model the thermal history at various locations using finite element modeling have been successful.
Pressure during welding
As the temperature in the joint increases, polymer begins to melt and a fusion zone is formed. The molten polymer in the fusion zone exerts an outward force on the surrounding solid polymer material, referred to as "cold zones". These cold zones cause a pressure to develop in the molten fusion zone. The pressure in the fusion zone takes some time to reach its maximum value, usually not reaching the peak until about a quarter of the way into the joining process. After the current is shut off and cooling begins, the pressure slowly decreases until the joint is uniform temperature.
Properties of joints
The strength of an electrofusion joint is measured using tensile and peel tests on coupons taken from the fusion zone of the joint. Two methods have been developed to assess the effect of fusion time on joint strength:
Simulating an electrofusion joint solely for testing purposes
Removing test coupons from standard electrofusion welded joints
The strength of the joint develops throughout the welding process, and this development is affected by the fusion time, joint gap, and pipe material. These are detailed below.
Effect of fusion time on joint strength
As fusion time begins, there is an incubation period where no strength develops. Once enough time has passed for the molten material to begin solidifying, the joint strength begins to develop before plateauing at the maximum strength. If power is applied after full joint strength is achieved, the strength will start to decline slowly.
Effect of joint gap on joint strength
The joint gap is the distance between the electrofusion fitting and the pipe material. When no joint gap is present, the resulting joint strength is high but not maximum. As joint gap increases, the joint strength increases to a point, then begins to decline fairly sharply. At larger gaps sufficient pressure cannot build during the fusion time, and the joint strength is low. The effect of joint gap on strength is why the scraping of the pipes before welding is a critical step. Uneven or inconsistent scraping can result in areas where the joint gap is large, leading to low joint strength.
Effect of pipe material on joint strength
Pipe materials with higher molecular weights (MW), or densities, will have slower material flow rates when in the molten state during fusion. Despite the differences in flow rates, the final joint strength is generally consistent over a fairly wide range of pipe molecular weights.
References
Plastic welding
Electric heating
Electricity
Thermodynamics | Electrofusion welding | [
"Physics",
"Chemistry",
"Mathematics"
] | 1,954 | [
"Thermodynamics",
"Dynamical systems"
] |
56,279,283 | https://en.wikipedia.org/wiki/Time%20synchronization%20in%20North%20America | Time synchronization in North America can be achieved with many different methods, some of which require only a telephone, while others require expensive, sensitive, and rare electronic equipment. In the United States, the United States Naval Observatory provides the standard of time, called UTC(USNO), for the United States military and the Global Positioning System, while the National Institute of Standards and Technology provides the standard of time for civil purposes in the United States, called UTC(NIST).
ITU-R Standard Frequency and Time Signals
A standard frequency and time signal service is a station that operates on or immediately adjacent to 2.5 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz, and 25 MHz, as specified by Article 5 of the ITU Radio Regulations (edition 2012). The US service is provided by radio stations WWV (Colorado) and WWVH (Hawaii).
The methods below provide either Coordinated Universal Time (UTC), which is defined by Recommendation ITU-R TF.460, or the official U.S. implementation of UTC, officially labeled UTC (NIST).
Internet time sources
Several different time synchronization protocols exist on the Internet, including:
GPS time synchronization
GPS receiver requirements
Minimum: GPS receiver that works with user chosen software; this requires some combination of GPGGA, GPRMC, GPZDA, GPGSA, and GPGSV sentences. This provides accuracy of between 1 and 2 seconds, and includes most, but not all modern GPS receivers.
Better: USB GPS receiver with the NMEA 0183 GPZDA sentence sent at least once a second. The developer of the Windows software NMEATime2 recommends GPS units with the U-blox 7 receiver, and this software uses a control loop to analyze the text of the GPS timing sentence, and claims to achieve 1 ms accuracy with the technique.
Better yet: RS-232 GPS receiver with the NMEA 0183 GPZDA sentence sent at least once a second, plus a 1PPS signal on DCD (1 μs accuracy possible with a real RS-232 port not on the USB bus; 1 ms possible with a RS-232 to USB adapter). The Garmin GPS 18x LVC appears to be the only such device that is generally available to consumers, but this then needs an external 5 V DC power source.
Best: Higher accuracy is possible with a high-end GPS receiver designed for time signal use, but these are very expensive (around $1000), feature OCXOs (oven-controlled crystal oscillators), and often require special software and physical RS-232 ports not connected via a USB bus to achieve that accuracy.
Utility frequency
In 2009 the Federal Energy Regulatory Commission made time error correction (TEC) of the power grid frequency mandatory. While TEC does not provide full synchronization (date and time) and synchronization is lost in case of a power outage it provides an inexpensive way to maintain high long term accuracy of synchronous clocks found in most household appliances. Once the initial time is set the power grid will typically maintain the accuracy within 10 seconds relative to UTC by adjusting frequency.
All time sources
Several different organizations provide publicly accessible recorded voice time sources, including the NIST Telephone Time of Day Service, see speaking clock. Other sources include GPS, terrestrial radio time signals, and internet services, as listed below.
See also
Time signal
Atomic clock
Network Time Protocol
Radio clock
List of radio time signal stations
WWV (radio station)
WWVH
WWVB
Extended Data Services (XDS "Time-of-Day Packet")
Standard frequency and time signal service
Coordinated Universal Time
List of UTC timing centers
Time and frequency transfer
Synchronization
Time synchronization over radio
References
External links
Recommendation ITU-R TF.768, Standard Frequencies and Time Signals
Time signals
Synchronization
Time in North America
Timekeeping | Time synchronization in North America | [
"Physics",
"Engineering"
] | 812 | [
"Telecommunications engineering",
"Physical quantities",
"Time",
"Timekeeping",
"Spacetime",
"Synchronization"
] |
56,279,481 | https://en.wikipedia.org/wiki/Cooperative%20pulling%20paradigm | The cooperative pulling paradigm is an experimental design in which two or more animals pull rewards toward themselves via an apparatus that they cannot successfully operate alone. Researchers (ethologists, comparative psychologists, and evolutionary psychologists) use cooperative pulling experiments to try to understand how cooperation works and how and when it may have evolved.
The type of apparatus used in cooperative pulling experiments can vary. Researcher Meredith Crawford, who invented the experimental paradigm in 1937, used a mechanism consisting of two ropes attached to a rolling platform that was too heavy to be pulled by a single chimpanzee. The standard apparatus is one in which a single string or rope is threaded through loops on a movable platform. If only one participant pulls the string, it comes loose and the platform can no longer be retrieved. Only by pulling together in coordination can the participants be successful; success by chance is highly unlikely. Some researchers have designed apparatus that involve handles instead of ropes.
Although many animals retrieve rewards in their cooperative pulling tasks, the conclusions regarding cooperation are mixed and complex. Chimpanzees, bonobos, orangutans, capuchins, tamarins, wolves, elephants, ravens, and kea appear to understand the requirements of the task. For example, in a delay condition, the first animal has access to the apparatus before the other. If the animal waits for its partner before pulling, this suggests an understanding of cooperation. Chimpanzees, elephants, wolves, dogs, ravens, and kea wait; grey parrots, rooks, and otters fail to wait. Chimpanzees actively solicit help when needed. They appear to recall previous outcomes to recruit the most effective partner. In a group setting, chimpanzees punish initial competitive behavior (taking food without pulling, displacing animals) such that eventually successful cooperation becomes the norm.
As for the evolution of cooperation, evidence from cooperative pulling experiments provides support for the theory that cooperation evolved multiple times independently. The fact that basic characteristics of cooperation are present in some mammals and some birds points to a case of convergent evolution. Within social animals, cooperation is suspected to be a cognitive adaptation.
Background
Many species of animals cooperate in the wild. Collaborative hunting has been observed in the air (e.g., among Aplomado falcons), on land (e.g., among lions), in the water (e.g., among killer whales), and under the ground (e.g., among driver ants). Further examples of cooperation include parents and others working together to raise young (e.g., among African elephants), and groups defending their territory, which has been studied in primates and other social species such as bottlenose dolphins, spotted hyenas, and common ravens.
Researchers from various disciplines have been interested in cooperation in animals. Ethologists study animal behavior in general. Comparative psychologists are interested in the origins, differences, and commonalities in psychological capacities across animal species. Evolutionary psychologists investigate the origin of human behavior and cognition, and cooperation is of great interest to them, as human societies are built on collaborative activities.
For animals to be considered cooperating, partners must take account of each other's behavior to pursue their common goal. There are various levels of cooperation. These increase in temporal and spatial complexity from performing similar actions, to synchrony (similar actions performed in unison), then coordination (similar actions performed at the same time and place), and finally collaboration (complementary actions performed at the same time and place). Researchers use controlled experiments to analyze the strategies applied by cooperating animals, and to investigate the underlying mechanisms that lead species to develop cooperative behavior.
Method
The cooperative pulling paradigm is an experimental design in which two or more individuals, typically but not necessarily animals, can pull rewards towards themselves via an apparatus they can not successfully operate alone. The cooperative pulling paradigm is the most popular paradigm for testing cooperation in animals.
Apparatus
The type of apparatus used in cooperative pulling experiments can vary. Researcher Meredith Crawford, who invented the experimental paradigm in 1937 while at the Yerkes National Primate Research Center, used an apparatus consisting of two ropes attached to a box that was too heavy to be pulled by a single chimpanzee. The standard apparatus is used in the loose-string task, designed by Hirata in 2003, in which a single string or rope is threaded through loops on a movable platform. If only one participant pulls the string, it comes loose and the platform can no longer be retrieved. Only by pulling together in coordination can the participants be successful; success by chance is highly unlikely. Some researchers have designed apparatus that involve handles instead of ropes. De Waal and Brosnan have argued that complex electronically-mediated devices are not conducive to arrive at findings regarding cooperation. This is in contrast to mechanical pulling devices, in which the animals can see and feel their pull having immediate effect. String-pulling tasks have advantages in terms of ecological validity for animals that pull branches with food towards themselves. Tasks in which participants have different roles in collaboration, such as for example, one pulls a handle and the other one needs to insert a stick, are considered outside the cooperative pulling paradigm.
Subjects
So far, fewer than twenty species have participated in cooperative pulling experiments: chimpanzees, bonobos, orangutans, capuchin monkeys, tamarins, macaques, humans, hyenas, wolves, dogs, elephants, otters, dolphins, rooks, ravens, parrots, and kea. Researchers have picked species that cooperate in the wild (e.g., capuchins), live in social structures (e.g., wolves), or have known cognitive abilities (e.g., orangutans). Most of the participating animals have been in human care at an animal research center; some lived semi-free at a sanctuary in their natural habitat. One study involved free animals (Barbary macaques) in the wild.
Conditions
To arrive at conclusions regarding cooperation, researchers have designed experiments with various conditions.
Delay
The first animal has access to the apparatus before the other one. If the animal does not wait for its partner this suggests a lack of understanding of the requirements for successful cooperation.
Recruitment
The subject recruits the partner (for example by opening a door) when the task requires cooperation.
Partner choice
The first animal gets to choose which animal from a pair it wants as a partner. In some cases individual animals from within a group can decide to join an animal already at the apparatus.
Apparatus choice
Instead of just one apparatus in the test area there are two identical ones. Animals can decide to work on the same one (which can lead to success) or on different ones (which will lead to failure). A further design involves two different apparatus. The first animal can decide whether to use an apparatus that can be operated alone or one that requires and has a partner waiting. A 'no rope' version involves an apparatus where everything is the same except for the rope on the partner's side being coiled up and not accessible to the partner.
Reward
Rewards can be food split equally over two bowls in front of each animal, or in one bowl only. The type of food can vary from many small pieces to a single big lump (e.g., slices of an apple vs. a whole apple). In combination with the apparatus choice, the reward for the joint-task apparatus is often twice as big as the reward for the solo apparatus. Another variation is a modified apparatus where one partner gets food before the other, requiring the first one to keep pulling despite already having received the reward.
Visibility
Typically the animals can see each other, all rewards, and all parts of the apparatus. To assess the role of visual communication, sometimes an opaque divider is placed such that the animals can no longer see each other, but can still see both rewards.
Training
Animals are often first trained with an apparatus that can be operated by one individual. For example, the two ends of a string are on top of each other and a single animal can pull both ends. A technique called shaping can be used by gradually extending the distance between the string ends, or by gradually extending the length of delay between the arrival of the first and second animal at the apparatus.
Findings
Overview
Although many animals retrieve rewards in their cooperative pulling tasks, the conclusions regarding cooperation are mixed and complex. Some researchers have attributed successful cooperation to random simultaneous action, or to the simple reactive behavior of pulling the rope when it moves. Many trials with capuchins, hyenas, parrots and rooks led to failure because one partner pulled without the other present, suggesting a lack of understanding of cooperation. A few researchers have offered the possible explanation that animals may understand cooperation to some extent but simply can not suppress the desire to have food they see.
But there is evidence that some species do have an understanding of cooperation and perform intentional coordination to achieve a goal.
Specifically, chimpanzees, bonobos, orangutans, tamarins, capuchins, elephants, wolves, ravens, and kea appear to understand how cooperation works. Chimpanzees not only wait for a partner, but will actively solicit help when needed. They appear to recall previous outcomes to recruit the most effective partner. In a group setting, chimpanzees punish initial competitive behavior (taking food without pulling, displacing animals) such that eventually, after many trials, successful cooperation becomes the norm. Bonobos, which are social animals with higher tolerance levels, can outperform chimpanzees on some cooperative tasks. Elephants will wait for 45 seconds for a partner to arrive before they start a cooperative pulling task; wolves do the same for 10 seconds. Dogs raised as pets are also able to wait for a partner, albeit only for a few seconds; pack dogs on the other hand rarely succeed in cooperative pulling in any condition. Among birds, ravens are able to learn to wait after many trials, while kea have set the record in waiting for a partner, 65 seconds. Mere knowledge of the presence of a partner is not enough for success: when a barrier with a small hole was placed between two capuchins, obstructing the view of the partner's actions, the success rate dropped. Of those species tested in the delay condition, parrots, rooks, and otters failed.
In 2008, Seed, Clayton and Emery said the study of the proximate mechanisms underpinning cooperation in animals was in its infancy, due in part to the poor performances of animals such as chimpanzees in early tests that did not take factors such as inter-individual tolerance into account. In 2006, Melis, Hare, and Tomasello had shown that the performance of chimpanzees in cooperative tasks was strongly influenced by levels of inter-individual tolerance. Several studies since have highlighted the fact that tolerance has a direct impact on cooperation success, as the more tolerant an animal is around food the better it performs. Subordinate animals seem simply not willing to risk being attacked by intolerant dominant animals, even if it means they will not obtain food either. In general, cooperation will not emerge if individuals can not share the spoils obtained through their joint effort. Temperament, whether an animal is bold or shy, has also been found to predict success.
As for the evolution of cooperation, evidence from cooperative pulling experiments appears to support the theory that cooperation evolved multiple times independently. The fact that basic characteristics of cooperation are present in some mammals and some birds points to a case of convergent evolution. Within social animals, cooperation is suspected to be a cognitive adaptation. The ability of humans to cooperate is likely to have been inherited from an ancestor shared with at least chimpanzees and bonobos. The superior scale and range of human cooperation comes mainly from the ability to use language to exchange social information.
Primates
Chimpanzees
Chimpanzees (Pan troglodytes) are smart, social animals. In the wild they cooperate to hunt, dominate rival groups, and defend their territory. They have participated in many cooperative pulling experiments. The first ever cooperative pulling experiment involved captive chimpanzees. In the 1930s Crawford was a student and researcher at the Yerkes National Primate Research Center. In 1937 he published a study of two young chimpanzees named Bula and Bimba pulling ropes attached to a box. The box was too heavy to be pulled in by just one ape. On top of the box was food. The two participants synchronized their pulling and were able to get the food reward in four to five short pulls. In a second part of the study, Crawford fed Bula so much prior to the test that she was no longer interested in the food reward. By poking her and pushing her hand towards the rope, Bimba tried to enlist her help in the task, with success. In a follow-up experiment with seven pairs of chimpanzees Crawford found none of the apes spontaneously cooperated. Only after extensive training were they able to work together to obtain food. They also failed to transfer this new skill to a slightly different task, in which the ropes were hanging from the ceiling.
Similar mixed results, not matching the cooperative abilities observed in chimpanzees in the wild, were obtained in later studies by other researchers using a variety of experimental set-ups, including the loose-string task pioneered by Hirata. Povinelli and O'Neill, for example, found that trained chimpanzees were unable to teach naive chimpanzees to cooperate on a Crawford-like box-pulling task. The naive animals did not imitate the experts. Chalmeau and Gallo found only two chimpanzees consistently cooperating in their handle-pulling task, and this involved one ape holding his own handle and waiting for the other to pull his. They concluded that social factors and not limited cognitive abilities were the reason for lack of widespread success, as they observed dominant chimpanzees controlling the apparatus and preventing others from interacting.
Melis, Hare, and Tomasello set up an experiment to control for such social factors. In a loose-string cooperative task without training they compared the ability of pairs of captive chimpanzees who in a non-cooperative setting were willing to share food with each other to pairs who were less inclined to do so. The results showed that food sharing was a good predictor for success in the cooperative pulling task. Melis, Hare, and Tomasello concluded that mixed results in the past could at least partially be explained by a failure to control for such social constraints. In a follow-up study with semi–free-ranging chimpanzees, again using the loose-string task, the researchers introduced the delay task, in which subjects were tested in their ability to wait for the partner. After mastering this task, they participated in a new task designed to measure their ability to recruit the partner. They found that the apes only recruited a partner (by unlocking a door) if the task required cooperation. When given the choice between partners, the apes chose the more effective one, based on their experience with each of them previously.
Suchak, Eppley, Campbell, Feldman, Quarles, and de Waal argued that even when experiments take social relationships into account, the results still do not match the cooperation capabilities observed in the wild. They set out to increase the ecological validity of their experiments by placing a handle-pulling apparatus in an open-group setting, allowing the captive chimpanzees themselves to choose to interact with it or not, and with whom. They also refrained from any training, offered as little human intervention as possible, and extended the duration to much longer than any test had ever done, to 47 days of 1 hour tests. The chimpanzees first discovered that cooperation could lead to success, but as more individuals became aware of this new way to obtain food, competition increased, taking the form of dominant apes displacing others, monopolizing the apparatus, and freeloading: taking the food others worked for. This competition led to fewer successful cooperative acts. The group did manage to restore and increase levels of cooperative behavior by various enforcement techniques: dominant individuals were unable to recruit partners and abandoned the apparatus, displacement was met with aggressive protest, and freeloaders were punished by third-party arbiters. When the researchers repeated this experiment with a brand new group of chimpanzees who not yet had established a social hierarchy, they again found that cooperation overcame competition in the long run. In a later study with a mix of novices and experts, Suchak, Watzek, Quarles, and de Waal found that novices learned rapidly in the presence of experts, although likely with limited understanding of the task.
Greenberg, Hamann, Warneken, and Tomasello used a modified apparatus that required two captive chimpanzees to pull, but delivered food to one ape first. They found that in many trials the apes who already had received a reward from joint effort kept pulling to help their partner obtain their food.
These partners did not need to gesture to solicit help, suggesting there was an understanding of what was wanted and needed.
Bonobos
Bonobos (Pan paniscus) are social animals that live in less hierarchical structures than chimpanzees. Hare, Melis, Woods, Hastings, and Wrangham set out to compare cooperation in chimpanzees and bonobos. They first ran a cofeeding experiment for each species. Pairs of bonobos were given two food dishes. In some trials both dishes had sliced fruit; in some one dish was empty and the other had sliced fruit; and in some one dish was empty and the other contained just two slices of fruit. The same set-up was then used for pairs of chimpanzees. When both dishes had food, there was no difference in behavior between bonobos and chimpanzees. But when only one dish contained food, bonobos were more than twice as likely to share food than chimpanzees. Bonobos were more tolerant of each other than chimpanzees. The researchers then ran a loose-string cooperation task with both dishes filled with sharable food. The results showed similar success rates for bonobos and chimpanzees, 69% of chimpanzee pairs and 50% of bonobo pairs spontaneously solving the task at least once within the six-trial test session.
In a third experiment, a year later, the same cooperation task was administered but now with different food distributions. The bonobos outperformed the chimpanzees in the condition where one dish only had food and the food was clumped making it easier to monopolize the food reward. Bonobos cooperated more often in this condition. On average a single chimpanzee partner monopolized food rewards more often than a single bonobo did. In the condition where both dishes were filled with food, chimpanzees and bonobos performed similarly, as they had done the year before. The researchers concluded that the differences in performance between species were not due to differences in age, relationships, or experience. It was the bonobos' higher social tolerance level that enabled them to outperform their relatives.
Orangutans
Orangutans (Pongo pygmaeus) are tool-using apes that are mostly solitary. Chalmeau, Lardeux, Brandibas, and Gallo tested the cooperative capabilities of a pair of orangutans, using a device with handles. Only through simultaneous pulling could the pair retrieve a food reward. Without any training the orangutans succeeded in the first session. Over the course of 30 sessions, the apes succeeded more quickly, having learned to coordinate. Across trials the researchers found an increase in a sequence of actions that suggested understanding of cooperation: first looking at the partner; then if the partner holds or pulls the handle, starting to pull.
The researchers also concluded that the orangutans learned a partner had to be present for success. For example, they observed that time spent alone at the apparatus decreased as the trials progressed. In some instances one orangutan pushed the other towards the free handle, soliciting cooperation. The researchers observed an asymmetry: one ape did all the monitoring and coordinating, the other one seemed to simply pull if the first one was present. Rewards did not have to be shared equally for success to appear, as one orangutan took 92% of all food. This ape anticipated the falling of food and stuck his hand out first, before recruiting help from his partner. Chalmeau, Lardeux, Brandibas, and Gallo concluded the apes appeared to understand the requirements of the cooperative task.
Capuchins
Capuchins (Sapajus apella) are large-brained monkeys that sometimes hunt cooperatively in the wild and
show, for nonhuman primates, unusually high levels of social tolerance around food. Early experiments to prove their ability to cooperate were unsuccessful. These tests involved capuchins having to pull handles or press levers in complex devices that the animals did not understand. They did not pull the handle more often when a partner was pulling; both novices and experienced participants kept pulling even in situations where success was impossible. Visalberghi, Quarantotti, and Tranchida concluded that there was no evidence of an appreciation of the role played by the partner.
The first test with evidence of cooperation in capuchins happened when de Waal and Brosnan adopted Crawford's pulling paradigm. Two captive monkeys were situated in adjacent sections of a test chamber, with a mesh partition between them. In front of them was an apparatus consisting of a counter-weighted tray with two pull bars and two food cups. Each monkey had access to only one bar and one food cup, but could see both, and only one cup was filled with food. The tray was too heavy for one monkey to pull it in, with weights established over trials lasting three years. Only when they worked together and both pulled could they move the tray, enabling one of them to grab the food. Trained monkeys were much more successful if they both obtained rewards after pulling than if only one of them received rewards. The pull rate dropped significantly when monkeys were alone at the apparatus, suggesting an understanding of the need for a partner. In later tests, researchers replaced the mesh partition with an opaque barrier with a small hole, so that the monkeys could see the other one was there but not their actions. This dramatically reduced success in cooperation.
De Waal and Berger used the cooperative pulling paradigm to investigate animal economics. They compared the behavior when both transparent bowls were loaded with food to when just one was loaded, and with a solo task where the partner was only an observer and unable to help. They found that captive capuchin monkeys were willing to pull even if their bowl was empty and it was uncertain if their partner would share food. In 90% of cases the owner of the food did indeed share the food. Food was shared more often if the partner actually worked for it than just being an observer.
Brosnan, Freeman, and de Waal tested captive capuchin monkeys on a bar-pulling apparatus with unequal rewards. Contrary to their expectations, rewards did not have to be distributed equally to achieve success. What mattered was the behavior in an unequal situation: pairs that tended to alternate which monkey received the higher-value food were more than twice as successful in obtaining rewards than pairs in which one monkey dominated the higher-value food.
Tamarins
Cottontop tamarins (Saguinus oedipus) are small monkeys who take care of their young cooperatively in the wild. Cronin, Kurian, and Snowdon tested eight captive cottontop tamarins in a series of cooperative pulling experiments. Two monkeys were put on opposite sides of a transparent apparatus containing food. Only if both monkeys pulled a handle on their side of the apparatus towards themselves at the same time would food drop down for them to obtain.
The tamarins were first trained, through shaping techniques, to use the handles successfully by themselves. In the joint pulling test pairs were successful in 96% of trials.
The researchers then ran a second study in which a tamarin was tested alone. The results showed that tamarins pulled the handles at a lower rate when alone with the apparatus than when in the presence of a partner. Cronin, Kurian, and Snowdon concluded from this that cottontop tamarins have a good understanding of cooperation. They suggest that cottontop tamarins have developed cooperative behavior as a cognitive adaptation.
Macaques
Molesti and Majolo tested a group of wild Barbary macaques (Macaca sylvanus) in Morocco to see if they would cooperate, and if so, what determined their partner choice. Macaques live in complex social environments and are relatively tolerant socially. After solo training, the researchers presented a loose-string apparatus for the cooperative task, which the animals were free to use.
Most animals that passed solo training were successful in spontaneously cooperating to obtain food (22 out of 26). More than half the pairs that chose to cooperate were juvenile-adult pairs. More than two monkeys pulling was never observed; stealing food from a partner was rare. After a first successful cooperation, they were more likely to pull when a partner was directly available, but this was not always the case. Molesti and Majolo did not rule out that pulling while no one held or pulled the other end of the rope was simply a signal to actively recruit a potential partner.
The researchers randomly introduced control trials in which the solo apparatus was set up as well. The macaques preferred to get the food alone when a partner was not needed during the control.
The extent to which a monkey tolerated another was a good predictor for initiating cooperation.
An individual was also found to be more successful with partners with whom they had a strong social bond.
Pairs sharing a similar temperament were more likely to initiate cooperation.
The quality of the relationship seemed to play an important role in the maintenance of cooperation over time.
Humans
Rekers, Haun, and Tomasello tested the cooperation abilities and preferences of humans (Homo sapiens) and compared them to chimpanzees.
The researchers provided 24 three-year-old children with some basic training in pulling food rewards towards themselves; in pairs using a loose-string setup, and solo training in which the two ends of a rope were tied together. They then tested the children in an apparatus choice set-up. On one side was the loose end of a rope that threaded through the apparatus to the other child. On the other side were two ends of a rope that when pulled would pull a platform towards both the child and their partner. Both the joint-operator platform and the solo-operated platform were holding two food dishes, all containing the same amounts of food. That is, from a partner's perspective, on one side the child had to pull to get food; on the other the partner could get food without any effort. The children chose the joint-operated board in 78% of trials.
The researchers then changed the design to ascertain if this choice preference was due to wishing to avoid freeloading and it may be that the children did not like their partner getting food without making any effort. In the modified set-up the partners never received any reward, not from the joint-operated apparatus and not from the solo-operated apparatus. Children again chose the joint-operated platform significantly more often, in 81% of trials. As in the first study, there was no significant difference in the time taken to obtain the food reward between using one side or the other. These results suggest that to obtain food, children prefer to work together with a partner as opposed to working alone. The chimpanzees in their study appeared to choose between the two platforms randomly, indicating no preference to work collaboratively. However, Bullinger, Melis, and Tomasello showed that chimpanzees actually exhibit a preference for working alone, unless cooperation is associated with higher pay-offs.
Other mammals
Hyenas
Captive spotted hyenas (Crocuta crocuta), social carnivores that hunt in groups, have cooperated to obtain food rewards by pulling ropes in an experimental setting. Mimicking the natural choice hunting hyenas face when deciding which of many prey to jointly attack, researchers Drea and Carter set up two devices instead of one, as previously used in all cooperative pulling tasks with other species. With four ropes to pull from, the animals had to pick the two belonging to the same device to be successful. If two vertically suspended ropes were simultaneously tugged, a spring-controlled trap door of an elevated platform was opened and previously hidden food dropped to the floor.
Another innovation was the introduction of more than two animals. One of the many factors the researchers controlled for was the Clever Hans effect (an effect in which humans unwittingly provide cues to animals), which they did by removing all humans from the test and by recording experiments on video.
After extensive solo trials, all hyenas were successful in cooperating, displaying remarkable efficiency even on their first try. On average, hyenas pulled on ropes more often when their companion was nearby and available to fulfil its partnership role. With only a few solo trials, the success rate of the cooperation task was very low for pairs. In groups of four hyenas, all trials were successful, regardless of the number of reward platforms. Thereafter, group exposure to a cooperation task had enhancing effects on pairwise performance. Social factors such as group size and hierarchy played a role. For instance, groups with a dominant member were far less successful than groups without, and lower-ranking animals were faster and consistently successful. When pairing experienced cooperators with animals new to the cooperation task, the researchers found that experienced animals monitored the novices and modified their behavior to achieve success. Despite initial accommodation, the pattern of rank-related social influences on partner performance also appeared in these tests with novices.
Dogs
Ostojić and Clayton administered the loose-string cooperation task to domestic dogs (Canis familiaris). Pet dogs first were given a solo task in which the string ends were close enough for one dog to pull at both. Then they were given a transfer test to assess if they could generalize their newly learned rule to novel situations. Finally, the joint task was administered. Dog pairs always came from the same household. In half of the joint tasks one of the pair of dogs was shortly delayed by an obstacle course. All dogs that learned to master the solo task solved the joint task within 60 trials. In the delayed condition, the not-delayed dog waited before pulling most of the time, but only for a few seconds. The researchers also tested dog–human pairs, again in delayed and not-delayed conditions. Dogs were equally successful when working with humans in the non-delayed condition, but far less successful when they had to wait for the human, who on average arrived with a 13-seconds longer delay than the delayed dog in the dog–dog trials. Ostojić and Clayton concluded that inhibiting the necessary action was not easy for dogs. They ruled out that dogs simply went for any moving string, as in the dog–human trials the humans did not pull hard enough to make the other end move. They attributed success to the dogs' ability to read the social cue of their partner's behavior, but could not rule out that visual feedback of seeing rewards incrementally move closer also played a role.
These results with pet dogs stand in stark contrast to the results with pack dogs, which in a study by Marshall-Pescini, Schwarz, Kostelnik, Virányi, and Range rarely succeeded in obtaining food. The researchers theorized that pet dogs are trained not to engage in conflicts over resources, promoting a level of tolerance, which may facilitate cooperation. The pack dogs were used to competition over resources and thus were likely to have conflict avoidance strategies, which constrain cooperation.
Wolves
Marshall-Pescini, Schwarz, Kostelnik, Virányi, and Range set out to test two competing hypotheses regarding cooperation in wolves (Canis lupus) and dogs. On the one hand, it could be theorized that dogs have been selected, during domestication, for tame temperaments and an inclination to cooperate and therefore should outperform wolves on a cooperative pulling task. On the other hand, it could be argued that dogs have evolved to become less able to work jointly with other dogs because of their reliance on humans. Wolves rely on each other for hunting, raising young and defending their territory; dogs rarely rely on other dogs. The researchers set up a cooperative pulling task for captive wolves and pack dogs. Without any training on this task, five of the seven wolf pairs were successful at least once, but only one dog pair out of eight managed to obtain food, and only once. After solo training, again the wolves far outperformed the dogs on the joint task. The researchers concluded that the difference does not stem from a difference in understanding of the task (their cognitive capabilities are largely the same), nor from a difference in social aspects (for both species, aggressive behavior by dominant animals was rare, as was submissive behavior by lower ranked ones). More likely is that dogs avoid potential conflict over a resource more than wolves do, something which has been observed in other studies as well.
The wolves, but not the dogs, were then tested in pairs in a set-up with two identical apparatus 10 meters (39 ft) apart, requiring them to coordinate in time and space. In 74% of the trials they succeeded. The stronger the bond between the partners and the smaller the distance in rank, the better they performed. In a subsequent delay condition, with the second wolf released 10 seconds after the first, most wolves did well, one being successful in 94% of trials.
Elephants
Elephants have a complex social structure and large brains that enable them to solve many problems. Their size and strength do not make them easy candidates for experiments. Researchers Plotnik, Lair, Suphachoksahakun, and de Waal adapted the apparatus and task to elephant requirements. They trained captive Asian elephants (Elephas maximus) to use a rope to pull a sliding platform with food on it towards themselves. Once the elephants managed this solo task, the researchers introduced a loose-string apparatus by threading the rope around the platform. At first, two elephants were released simultaneously to walk side by side in two lanes to the two loose ends of the rope. Using their trunks the animals coordinated their actions and retrieved the food.
At this stage they could simply be applying a 'see the rope, pull the rope' strategy. To see whether they understood the requirements of the task the researchers introduced a delay for one elephant, initially of 5 seconds and ultimately of 45 seconds. At first the lead elephant failed to retrieve the food but was soon seen to wait for a partner. Across 60 trials the first elephant waited for the second one before pulling in most cases. In a further control the researchers prevented the second elephant from being able to access its end of the rope. In almost all of these cases the first elephant did not pull the rope, and four of the six returned when they saw the other rope end was not going to be accessible to their partner. The researchers concluded that this suggested the elephants understood they needed their partner to be present and to have access to the rope to succeed. One elephant never pulled the rope but simply put her foot on the rope and let the partner do all the pulling. Another one waited for his partner's release at the starting line rather than waiting at the rope. Plotnik, Lair, Suphachoksahakun, and de Waal conceded that it is difficult to distinguish learning from understanding. They did prove that elephants show a propensity towards deliberate cooperation. The speed with which they learned the critical ingredients of successful cooperation puts them on par with chimpanzees and bonobos.
Otters
Schmelz, Duguid, Bohn, and Völter presented two species of captive otters, giant otters (Pteronura brasiliensis) and Asian small-clawed otters (Aonyx cinerea), with the loose-string task. Both species raise young cooperatively and live in small groups. Because giant otters forage together but small-clawed otters do not, the researchers expected the giant otters to do better in the cooperative pulling experiment. After solo training, they tested both species in a group setting, to maintain ecological validity. The results showed that most pairs of otters were successful in pulling food rewards to themselves. Contrary to expectation, there was no difference between the species in success rate. In a subsequent experiment the researchers first lured the group away from the apparatus into the opposite corner of the enclosure. Then they put food on the apparatus and observed what happened when the first otter arrived at the nearest end of the rope, as there was no partner yet at the other end. Very few trials led to success in this condition as otters pulled the rope as soon as they could. The researchers concluded from this that the otters did not understand the necessary elements of successful cooperation, or, alternatively, they understood but were unable to inhibit the desire to reach for the food. When the same task was repeated with a longer rope, success rate did go up, but the otters appeared unable to learn from this and be successful in the next task with the rope length restored to the original length. Schmelz, Duguid, Bohn, and Völter suggested that an understanding of cooperation may not be required for successful cooperation in the wild. Cooperative hunting may be possible through situational coordination and mutualism, without any complex social cognitive abilities.
Dolphins
Two groups of researchers (first Kuczaj, Winship, and Eskelinen, and then Eskelinen, Winship, and Jones) adapted the cooperative pulling paradigm for captive bottlenose dolphins (Tursiops truncatus). As apparatus they used a container which could only be opened at one end if two dolphins each pulled a rope on either end. That is, the dolphins would have to face each other and pull in opposite directions. They first attached the container to a stationary dock so a single dolphin could learn to open it and get the food reward. Then they ran trials in which the container was free floating in a large test area with six dolphins. In Kuczaj, Winship, and Eskelinen's study, only two dolphins interacted with the container. In eight of the twelve trials they pulled simultaneously and obtained food. Once, they also managed to open the container through asynchronous pulling, and once a single male dolphin managed to open it by himself. Kuczaj, Winship, and Eskelinen admitted that this behavior may appear to be cooperation but could possibly be competition. They conceded it is possible that the dolphins did not understand the role of the other dolphin, but instead simply tolerated it pulling on the other side. King, Allen, Connor, and Jaakkola later argued that this design makes for a competitive 'tug-of-war', not cooperation, and any conclusions regarding cooperation should therefore be invalid.
Birds
Rooks
Rooks (Corvus frugilegus) are large-brained members of the bird family Corvidae. They live in big groups and have a high level of social tolerance. Researchers Seed, Clayton, and Emery set up a loose-string experiment with eight captive rooks. They were first trained in a solo task, with the string ends placed at 1 cm, 3 cm and ultimately 6 cm apart (0.4, 1.2, and 2.4 inch respectively). A pair's willingness to share food was then tested, and was found to differ somewhat between pairs, although food was rarely monopolized by a dominant bird. In the cooperative task, all pairs were able to solve the cooperation problem and retrieve food; two pairs managed this in their first session. Food sharing was a good predictor for successful cooperation.
In a subsequent delay test, where one partner had access to the apparatus first, all rooks pulled the string without waiting for their partner to enter the test area in the majority of trials. In a second variant, birds were given a choice between a platform they could operate successfully alone and one that required a pulling partner. When tested alone, four of the six rooks showed no significant preference for either platform. Seed, Clayton, and Emery concluded that although successful at the cooperation task, it seemed unlikely that the rooks had an understanding of when cooperation was necessary.
Researchers Scheid and Noë subsequently found that successful cooperation in rooks depended to a large extent on their temperament. In their loose-string experiment with 13 captive rooks they distinguished between bold and shy animals. The results were mixed, ranging from some pairs cooperating successfully every time to some pairs never cooperating. In 81% of cases a rook should have waited for a partner, but it did not and started pulling. Scheid and Noë concluded their experiment provided no evidence for or against rooks having an understanding of the task. They attributed any cooperation success to common external cues and not coordination of actions. But all subjects did better when they were paired with a bolder partner. The researchers suggested that in evolution, cooperation can emerge because bolder individuals encourage a risk-averse one to engage.
Ravens
Massen, Ritter, and Bugnyar investigated the cooperative capabilities of captive common ravens (Corvus corax), a species that frequently cooperates in the wild. They found that without training ravens cooperated in the loose-string task. The animals did not seem to pay attention to the behavior of their partners while cooperating, and, like rooks, did not seem to understand the need for a partner to be successful. Tolerance of their partner was a critical factor for success. In one condition the researchers let ravens choose a partner from a group to cooperate with. Overall success was higher in this condition, and again, individuals that tolerated each other more had more success. The ravens also paid attention to reward distribution: they stopped cooperating when being cheated upon.
Asakawa-Haas, Schiestl, Bugnyar, and Massen subsequently ran an open-choice experiment with eleven captive ravens in a group setting, using nine ravens from one group and two newcomers. They found that the ravens' decision which partner to cooperate with was based on tolerance of proximity and not on whether they were part of the group or not. The ravens in this experiment learned to wait for their partner and inhibit pulling the string too soon.
Grey parrots
Researchers Péron, Rat-Fischer, Lalot, Nagle and Bovet had captive grey parrots (Psittacus erithacus) try to cooperate in a loose-string experimental set-up. The grey parrots were able to act simultaneously but, like the rooks, largely failed to wait for a partner in the delay task. They did not make any attempts to recruit a helping partner. The parrots did take the presence of a partner into account, since they all pulled more when a partner was present, but this could be explained by instrumental learning rather than a real understanding of the task. The researchers also gave the parrots a choice between two apparatus, one from the solo task and one from the loose-string task, now stacked with double the food per bird. Two of the three parrots chose the solo apparatus when alone, and two of the three parrots preferred the joint-task apparatus when tested with a partner. When paired up, social preferences and tolerance affected the likelihood a pair cooperated.
Kea
Kea (Nestor notabilis), parrots native to New Zealand, are a distant relative of the grey parrot. They live in complex social groups and do well on cognitive tests. Heaney, Gray, and Taylor gave four captive kea a series of cooperative loose-string tasks. After solo training and shaping with string ends increasingly further apart, two birds were released simultaneously in a joint loose-string task. Both pairs did very well, one pair failing only 5 in 60 trials. Shaping was then used in a delay task, with the partner released after one second, then two, and gradually up to 25 seconds later than the first bird.
The birds managed to wait for a partner between 74% and 91% of test trials, including success at 65 seconds delay, longer than any other animal of any species had been tested for.
To assess if this success could be explained by the learning of a combination of cues, such as seeing a partner while feeling tension on the string, or by a proper understanding of cooperation, the researchers randomly gave the kea a set-up they could solve alone or one in which they needed to cooperate with a delayed partner.
Three of the four kea were successful at a significant rate: they chose to wait when they had to and immediately pulled when the task could be done alone. However, when the researchers modified the set-up and coiled up the string end of the delayed partner, no bird was successful at discriminating between a duo platform with both ends of string available to both kea and a duo platform with the partner's string coiled out of reach.
The researchers were not able to determine the reason for this result. They speculated it could be that kea do have an understanding of when they need a partner but do not have a clear idea of the role their partner plays in relation to the string, or they may lack of a full causal understanding of how the string works. Finally, the researchers attempted to ascertain if kea have a preference for working alone or together. No preference was found in three of the four kea, but one kea preferred the duo platform significantly more. Heaney, Gray, and Taylor concluded that these results put kea on a par with elephants and chimpanzees in terms of cooperative pulling.
These conclusions are in sharp contrast to those of Schwing, Jocteur, Wein, Noë, and Massen, who tested ten captive kea in a loose-string task on an apparatus that provided limited visibility to follow the trajectory of the string. After training with a human partner (no solo training was done), only 19% of trials led to the birds obtaining food in the joint task. The researchers found that the closer the birds were affiliated, the more successful they were in the cooperation task. The kea did not seem to understand either the mechanics of the loose-string apparatus or the need of a partner, as in training with humans they still pulled the string even when the human was too far away or facing the wrong way. The way rewards were distributed had a small effect on the likelihood of cooperation attempts. The difference in social rank or dominance did not seem to matter.
Footnotes
References
Notes
Bibliography
External links
First ever cooperative pulling experiment (video) Crawford (1937)
Elephants in cooperative pulling experiment (video) Plotnik et al. (2011)
Wolves and dogs in cooperative pulling experiment (video) Marshall-Pescini et al. (2017)
Chimpanzees in cooperative pulling experiment (video) Suchak et al. (2014)
Dolphins in pulling experiment (video) Kuczaj et al. (2015)
TED Talk Moral behavior in animals (video) Frans de Waal
Design of experiments
Ethology
Animal cognition
Animal testing | Cooperative pulling paradigm | [
"Chemistry",
"Biology"
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"Animal testing",
"Behavior",
"Animals",
"Behavioural sciences",
"Animal cognition",
"Ethology"
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56,279,846 | https://en.wikipedia.org/wiki/Walery%20Mroczkowski | Walery Karłowicz Mroczkowski (6 April 1840 – 1 October 1889) was a Polish insurgent in the 1863 January Uprising. He was arrested and imprisoned by the Prussian authorities. Upon release in 1865, he was sent into exile and travelled to Italy, Switzerland, London and finally settled in France. While in Florence he met Mikhail Bakunin and became an anarchist and a member of the latter's close circle. He is also known as a portrait photographer in France, working under the pseudonym, "Ostroga" or "Valerien Ostroga".
Early life
Nothing is known, at present, of Mroczkowski's family background or childhood. As the earliest written record, the diary of his uprising colleague Szymon Kotylla published in 1907, indicates that he was a student at the Medical Academy in Warsaw (1860–1861), he would have had access to funds for his interrupted studies and for travel to Italy for military training. As a convinced patriot he went to Cuneo in Italy to attend the Polish military cadet school (1861–62), commanded by Ludwik Mierosławski in preparation for a future uprising.On his return to Poland in 1862 the National Central Committee despatched him to the Augustów Governorate, under cover of being a journalist with the nom-de-guerre "Wincenty Kamiński", to help organize military units. He was a Biebrza district commissar, local Plenipotentiary for the Rada Narodowa (National revolutionary council) and was responsible for the purchase of armaments. The following year he took part in a series of skirmishes and in May 1863 he distinguished himself at the head of a relief party in the battle of Kazlų Rūda. By November 1863 he was in Eastern Prussia where he was arrested and imprisoned in Posen-West Prussia. In 1865 he was released and forced into exile.
Encounter with Anarchism
As an activist prior to his exile Mroczkowski was regarded as a democrat and an apostle of the Emancipation of serfs. On a trip to Florence in 1865 he met Mikhail Bakunin who befriended him and suggested he accompany him on a trip to Naples. There he was introduced to princess Zoë Sumarokov, (born 1828). She was the estranged wife of Prince Alexei Obolensky with whom she had six children, and was living with them among revolutionaries escaped from Russia. She would become Mroczkowski's lover and later his wife and have two children with him.
While staying on Ischia with Bakunin in 1866, Mroczkowski together with his now partner, Zoë, produced a French translation of the Revolutionary Catechism, Bakunin's founding text for the secret "international revolutionary society" they were planning. Bakunin's Pet name for Mroczkowski was the affectionate diminutive, "Mrouk". In Polish "mruk" means the "grunter" or the "silent one".
A Swiss interlude
In 1867, they decided to settle in Switzerland. Initially they stayed in Vevey, then in Geneva. There they met the French geographer and theorist, Élisée Reclus, whose daughter would later become the companion of the Mroczkowskis' son, Felix. In 1868 having become members of the First Internationale and then of the central committee of the
League of Peace and Freedom, after the schism in the aftermath of the Berne Convention, Mroczkowski and Bakunin formed a group to oppose the ideology of Karl Marx. Mroczkowski was also involved in drawing up plans for the refurbishment of the villa, La Baronata perched above Lake Maggiore, a retirement retreat built for Carlo Cafiero, who initially "gave" it to Bakunin, but on discovering that his fortune was leaching away, was able to get it back.
London episode
In 1869 they left Switzerland and travelled as a couple to London and for about two years moved there in revolutionary circles that included people such as Karl Marx and Walery Wroblewski
A new career in photography
Since Prince Obolensky had forcibly abducted his children from his wife, Zoë, in 1869, her income dropped considerably. Having left Switzerland and now London, Mroczkowki and Zoë took up residence in Menton. There in 1871 Mroczkowski opened a photographic studio as "Walerian M.Ostroga", specialising in portraits. Eventually, he split his time working in Trouville-sur-Mer during the Summer and Menton in Winter. Living in two places enabled him to justify extensive travel and disguise his anarchist activities. Work as a photographer helped him keep his family – his Common-law marriage to Zoë and their two children, Félix (1867–1936) and Léonie (1871–1947). They were finally married after the death of Prince Alexei Vasilievitch, Zoe's husband, and were able to buy a villa, "les mouettes", that became "villa Ostroga".
Walery Mroczkowski/Valerien Ostroga died on 1 October 1889 in Paris and was buried in the Vieux-Château cemetery in Menton. His children and descendants adopted the surname "Ostroga", being easier to write and pronounce in French.
Gallery
Bibliography
Mroczkowski Walery (1840–1889) powstaniec 1863, emigrant. Polski Słownik Biograficzny vol. 22 p. 185
Laskowski, Piotr. (2016) "Jedyny wybitny bakuninowiec"- Walerian Mroczkowski (1840–1889) dans Studia z Dziejów Anarchizmu (2) w Dwusetleciu Urodzin Michała Bakunina.''' Red. Skrzycki, Radosław. Szczecin: Wydawnictwo Naukowe Uniwersytetu Szczecińskiego. p. 81–122.
See also
Suwałki Governorate
References
External links
Portrait National Museum of Warsaw (Muzeum Narodowe w Warszawie)
"Powstanie Styczniowe w illustracjach prasy epoki" Newspaper Illustrations of the January Uprising, featuring the battle at Kozłowa Ruda'', in which Mroczkowski took part and is mentioned in the text. See page 35
Group photo with Bakunin
Photos on Gallica BnF
Photos Trieste Library
Un quatrième Walery photographe Hugues Fontaine's Blog
"Ostroga" genealogy on pierfitgeneanet
1840 births
1889 deaths
19th-century atheists
19th-century French photographers
Anarchist theorists
Anarcho-communists
Collectivist anarchists
Critics of Marxism
Critics of work and the work ethic
Polish participants of the January Uprising
Libertarian socialists
Materialists
Members of the International Workingmen's Association
Mikhail Bakunin
People from Olonets
Polish anarchists
Polish atheists
19th-century Polish nobility
Portrait photographers
Polish political prisoners in the Prussian partition | Walery Mroczkowski | [
"Physics"
] | 1,446 | [
"Materialism",
"Matter",
"Materialists"
] |
56,280,107 | https://en.wikipedia.org/wiki/Detection%20of%20Intrusions%20and%20Malware%2C%20and%20Vulnerability%20Assessment | The Detection of Intrusions and Malware, and Vulnerability Assessment (DIMVA) event is an annual conference designed to serve as a general forum for discussing malware and the vulnerability of computing systems to attacks, advancing computer security through the exchange of ideas. It is one of the projects of the German Informatics Society (GI).
According to the official DIMVA website on its 2017 event, "Each year, DIMVA brings together international experts from academia, industry, and government to present and discuss novel research in these areas." Said conference was held from 6 July to 7 July in the city of Bonn, Germany. It was sponsored by entities such as Google, Rohde & Schwarz, and VMRay.
A conference report that demonstrated how to externally manipulate an Alfa Romeo Giulietta's networked safety systems and essentially hack into the vehicle attracted notice from publications such as Fiat Chrysler Authority.
References
Computer security organizations | Detection of Intrusions and Malware, and Vulnerability Assessment | [
"Technology"
] | 187 | [
"Computing stubs",
"Computer conference stubs"
] |
56,281,176 | https://en.wikipedia.org/wiki/Pfaffian%20orientation | In graph theory, a Pfaffian orientation of an undirected graph assigns a direction to each edge, so that certain cycles (the "even central cycles") have an odd number of edges in each direction. When a graph has a Pfaffian orientation, the orientation can be used to count the perfect matchings of the graph. This is the main idea behind the FKT algorithm for counting perfect matchings in planar graphs, which always have Pfaffian orientations. More generally, every graph that does not have the utility graph as a graph minor has a Pfaffian orientation, but does not, nor do infinitely many other minimal non-Pfaffian graphs.
Definitions
A Pfaffian orientation of an undirected graph is an orientation in which every even central cycle is oddly oriented. The terms of this definition have the following meanings:
An orientation is an assignment of a direction to each edge of the graph.
A cycle is even if it contains an even number of edges.
A cycle is central if the subgraph of formed by removing all the vertices of has a perfect matching; central cycles are also sometimes called alternating circuits.
Cycle is oddly oriented if each of the two orientations of is consistent with an odd number of edges in the orientation.
Application to counting matchings
Pfaffian orientations have been studied in connection with the FKT algorithm for counting the number of perfect matchings in a given graph. In this algorithm, the orientations of the edges are used to assign the values to the variables in the Tutte matrix of the graph. Then, the Pfaffian of this matrix (the square root of its determinant) gives the number of perfect matchings. Each perfect matching contributes to the Pfaffian regardless of which orientation is used; the choice of a Pfaffian orientation ensures that these contributions all have the same sign as each other, so that none of them cancel.
This result stands in contrast to the much higher computational complexity of counting matchings in arbitrary graphs.
Pfaffian graphs
A graph is said to be Pfaffian if it has a Pfaffian orientation.
Every planar graph is Pfaffian.
An orientation in which each face of a planar graph has an odd number of clockwise-oriented edges is automatically Pfaffian. Such an orientation can be found by starting with an arbitrary orientation of a spanning tree of the graph.
The remaining edges, not in this tree, form a spanning tree of the dual graph, and their orientations can be chosen according to a bottom-up traversal of the dual spanning tree in order to ensure that each face of the original graph has an odd number of clockwise edges.
More generally, every -minor-free graph has a Pfaffian orientation. These are the graphs that do not have the utility graph (which is not Pfaffian) as a graph minor. By Wagner's theorem, the -minor-free graphs are formed by gluing together copies of planar graphs and the complete graph along shared edges. The same gluing structure can be used to obtain a Pfaffian orientation for these graphs.
Along with , there are infinitely many minimal non-Pfaffian graphs. For bipartite graphs, it is possible to determine whether a Pfaffian orientation exists, and if so find one, in polynomial time.
References
Graph theory objects
Matching (graph theory) | Pfaffian orientation | [
"Mathematics"
] | 707 | [
"Matching (graph theory)",
"Mathematical relations",
"Graph theory",
"Graph theory objects"
] |
56,281,215 | https://en.wikipedia.org/wiki/Fuel%20%28journal%29 | Fuel is a biweekly peer-reviewed scientific journal covering research on fuel. It was established in 1922 and published by Butterworths Scientific Publications as Fuel in Science and Practice, obtaining its current name in 1948. It is published by Elsevier and the editor-in-chief is Bill Nimmo (University of Sheffield).
Abstracting and indexing
The journal is abstracted and indexed in:
According to the Journal Citation Reports, the journal has a 2022 impact factor of 7.4.
References
External links
Academic journals established in 1922
Biweekly journals
Elsevier academic journals
English-language journals
Energy and fuel journals | Fuel (journal) | [
"Environmental_science"
] | 127 | [
"Environmental science journals",
"Energy and fuel journals"
] |
56,281,564 | https://en.wikipedia.org/wiki/NGC%206039 | NGC 6039 is a massive lenticular galaxy located about 460 million light-years away in the constellation Hercules. NGC 6039 was discovered by astronomer Édouard Stephan on June 27, 1870 and later rediscovered by astronomer Lewis Swift on June 27, 1886. NGC 6039 is member of the Hercules Cluster, which is part of the CfA2 Great Wall.
See also
List of NGC objects (6001–7000)
NGC 1316
References
External links
Hercules (constellation)
Lenticular galaxies
6039
56972
Astronomical objects discovered in 1870
Hercules Cluster
Discoveries by Édouard Stephan | NGC 6039 | [
"Astronomy"
] | 114 | [
"Hercules (constellation)",
"Constellations"
] |
56,282,490 | https://en.wikipedia.org/wiki/PSLV-C40 | PSLV-C40 was the 42nd mission of the Indian Polar Satellite Launch Vehicle (PSLV) program in the XL configuration. PSLV-C40 successfully carried and deployed 31 satellites in Sun-synchronous orbits.
Overview
Two Surrey Satellite Technology satellites were launched, the 100 kg Carbonite-2 Earth Observation technology demonstrator and the 168 kg Telesat LEO Phase 1 communications satellite.
Four SpaceBEE sub-CubeSats were launched to test "2-way satellite communications and data relay", probably for the Silicon Valley company Swarm Technologies. However, the U.S. Federal Communications Commission (FCC) had denied regulatory approval for Swarm Technologies 10 cm × 10 cm × 2.8 cm BEE satellites as they were too small to be reliably tracked by the United States Space Surveillance Network, so may become an impact hazard to other satellites. If confirmed, the FCC may take regulatory action over these satellites.
Launched satellites
Astranis DemoSat-2
Carbonite-2
Cartosat-2F (Cartosat-2 series satellite)
ICEYE-X1
INS-1C
Microsat
PicSat
Arkyd-6
References
External links
Polar Satellite Launch Vehicle
Spacecraft launched by India in 2018
January 2018 events in India | PSLV-C40 | [
"Astronomy"
] | 255 | [
"Outer space stubs",
"Outer space",
"Astronomy stubs"
] |
56,283,993 | https://en.wikipedia.org/wiki/Octagon%20Systems | Octagon Systems Corporation is an industrial computer design and manufacturing company originally based in Westminster, Colorado. Octagon Systems designs, manufactures, sells, repairs and supports its line of industrial, mobile and rugged computer systems for industries including mining, military, transportation and others. The company has international representatives in Africa, Asia, Europe, North America and South America.
History
Early years (1980s)
Octagon Systems was founded in 1981, and introduced an embedded computer with a high level language and software development system and operating systems on a solid state disk. Octagon’s services and systems grew with industrial computer systems including the STD Bus market and development of single-board computers. Octagon Systems has been ISO certified since 1993.
New applications (2000s)
Octagon Systems’ XMB Mobile Servers were mentioned by the trade press in 2006. Octagon Systems was a founding member of the Small Form Factor Special Interest Group in 2007.
Octagon co-authored the EPIC embedded computing specification. Octagon’s products were used in public transportation systems, rugged computing systems for mining operations as well as others.
Industry expansion (2010s)
Octagon Systems products expanded into new markets continuing the sell of industrial, transportation and rugged computer systems. The U.S. Navy chose Octagon’s products for a contract to support amphibious warfare computing, and Octagon products were deployed in mines.
Acquired (2018)
In 2018, J-Squared Technologies acquired the TRAX family of Octagon products. The Westminster manufacturing facility was closed.
References
Computers
Software companies of the United States | Octagon Systems | [
"Technology"
] | 323 | [
"Computers"
] |
56,284,003 | https://en.wikipedia.org/wiki/QuIST | The Quantum Information Science and Technology Program (abbreviated as QUIST or QuIST) was a five-year, $100M DARPA research program that ran from FY 2001 – 2005. The initiative was jointly created by the Defense Sciences Office (DSO) and the Information Technology Office (ITO) to accelerate development in the field of quantum computing, quantum communications, quantum algorithms, and other high-priority quantum information applications. As a completed program, QuIST received an award from DARPA in 2008 for scientific breakthroughs previously conducted under its support.
Research
In 2004, QuIST-funded researchers demonstrated the DARPA Quantum Network, the first working quantum key distribution network. At its start, it employed coherent laser pulses over optical fiber media, sending unconditionally-secure messages between Harvard University, Boston University and BBN Technologies in Cambridge, Massachusetts. It later grew to a fully operational, 10 node network, conveying key material both through telecom fiber and the atmosphere. The work was given a DARPA award four years later.
See also
IARPA – Intelligence Advanced Research Projects Agency
QuEST – Quantum Entanglement Science and Technology
References
External links
DARPA
DARPA projects | QuIST | [
"Physics"
] | 236 | [
"Quantum mechanics",
"Quantum physics stubs"
] |
56,284,034 | https://en.wikipedia.org/wiki/MIR-2 | MIR-2 () is the version of the MIR computer developed by the Institute of Cybernetics of the Academy of Sciences of Ukrainian SSR under the guidance of Victor Glushkov. It was first produced in 1969.
Overview
The speed of the MIR-2 machine is about 12,000 operations per second. The capacity of the random access memory (12-μs circulation cycle) is 8,000 13-bit symbols. The read-only memory has a capacity of about 1.6 million bits with a cycle of 4 μs, which is enough to store several tens of thousands of micro-commands. There is a buffer memory for output information with a volume of 4000 10-bit words. As external devices were used: input from punched tape, output to punched tape, electric typewriter Soemtron, magnetic card drive, vector graphic display with light pen.
As the input language in the MIR-2 machine, a special high-level language Analitik was used, which developed the concepts of the MIR-1 built-in programming language and additionally allowed the formulation of tasks with analytic transformations of formulas, allowing analytical expressions for derivatives and integrals.
References
Soviet computer systems | MIR-2 | [
"Technology"
] | 241 | [
"Computer systems",
"Soviet computer systems"
] |
56,284,235 | https://en.wikipedia.org/wiki/Constructive%20development%20%28biology%29 | In biology, constructive development refers to the hypothesis that organisms shape their own developmental trajectory by constantly responding to, and causing, changes in both their internal state and their external environment. Constructive development can be contrasted with programmed development, the hypothesis that organisms develop according to a genetic program or blueprint. The constructivist perspective is found in philosophy, most notably developmental systems theory, and in the biological and social sciences, including developmental psychobiology and key themes of the extended evolutionary synthesis. Constructive development may be important to evolution because it enables organisms to produce functional phenotypes in response to genetic or environmental perturbation, and thereby contributes to adaptation and diversification.
Key themes of constructive development
Responsiveness and flexibility
At any point in time, an organism's development depends on both the current state of the organism and the state of the environment. The developmental system, including the genome and its epigenetic regulation, responds flexibly to internal and external inputs. One example is condition-dependent gene expression, but regulatory systems also rely on physical properties of cells and tissues and exploratory behavior among microtubular, neural, muscular and vascular systems.
Multiple modes of inheritance
Organisms inherit (i.e., receive from their predecessors) a diverse set of developmental resources, including DNA, epigenetic marks, organelles, enzymes, hormones, antibodies, transcription factors, symbionts, socially transmitted knowledge and environmental conditions modified by parents.
Developmental environments are constructed
In the course of development, organisms help shape their internal and external environment, and in this way, influence their own development. Organisms also construct developmental environments for their offspring through various forms of extra-genetic inheritance.
Distributed control
No single source of influence has central control over an organism's development. Whilst the genetic influence on development is fundamental, causation does not only occur from the bottom up, but also flows ‘downwards’ from more complex levels of organismal organization (e.g., tissue-specific regulation of gene expression). The result is that many features of organisms are emergent properties that are not encoded in the genome.
Mechanisms of constructive development
Constructive development is manifest in context-dependent gene expression, physical properties of cells and tissues, exploratory behavior of physiological systems and learning.
Context-dependent gene expression
Although all the cells of an organism contain the same DNA, there can be hundreds of different types of cells in a single organism. These diverse cell shapes, behaviors and functions are created and maintained by tissue-specific gene expression patterns and these can be modified by internal and external environmental conditions.
Physical properties of cells and tissues
Assembly of organs, tissues, cells and subcellular components are in part determined by their physical properties. For example, the cell membrane that forms a barrier between the inside and outside of the cell is a lipid bilayer that forms as result of the thermodynamic properties of the phospholipids it's made of (hydrophilic head and hydrophobic tails).
Exploratory processes
Exploratory processes are selective processes that operate within individual organisms during their lifetimes. In many animals, the vascular, immune and nervous systems develop by producing a variety of forms, and the most functional solutions are selected for and retained, while others are lost. For example, the ‘shape’ of the circulatory system is constructed according to the oxygen and nutrient needs of tissues, rather than being genetically predetermined. Likewise, the nervous system develops through axonal exploration. Initially muscle fibers are connected to multiple neurons but synaptic competition selects certain connections over others to define the mature pattern of muscle innervation. The shape of a cell is determined by the structure of its cytoskeleton. A major element of the cytoskeleton are microtubules, which can grow in random directions from their origin. Microtubule-associated proteins can aid or inhibit microtubule growth, guide microtubules to specific cellular locations and mediate interactions with other proteins. Therefore, microtubules can be stabilized in new configurations that give rise to new cell shapes (and potentially new behaviors or functions) without changes to the microtubule system itself.
Learning
In animals, many behaviors are acquired through learning. Social learning and cultural transmission are important sources of adaptive phenotypic plasticity, enabling animals to adapt to their environments even if those environments have not frequently been encountered in the evolutionary history of the species. Social learning also enables stable inheritance of many characters. Cross-fostering of great tit and blue tit chicks show that social learning can result in stable inheritance of species-typical foraging behaviors (foraging height, prey type, prey size, foraging method) as well as nest site choice, alarm calls, songs, and mate choice. Recent killer whale research has demonstrated the divergence of orcas into several species mediated by learned and socially transmitted differences in diets.
Constructive development and evolution
Within evolutionary biology, development has been traditionally viewed as under the direction of a genetic program (e.g.), and metaphors such as genetic ‘blueprint’, ‘program’ or ‘instructions' are still widespread in biology textbooks. By contrast, the constructive development perspective views the genome as a sub-system of the cell shaped by evolution to detect and respond to the signals it receives. These different perspectives affect evolutionary interpretations. One example is the evolutionary significance of environmentally induced phenotypes. Mary Jane West-Eberhard famously suggested that responses to the environment can be the starting point for evolutionary change, termed ‘plasticity-led evolution’. From a programmed development perspective, developmental plasticity is considered to be controlled by genetically specified switches or reaction norms. For these to produce functional responses to environmental change, their reaction norms must have been pre-screened by prior selection. Therefore, ‘plasticity-led evolution’ reduces to the standard evolutionary explanation of natural selection acting on genetic variation. Conversely, ‘plasticity-led evolution’ gains greater significance if development is constructive and open-ended. New functional phenotypes can emerge with little or no initial genetic modification (see facilitated variation), and provide the new raw material on which natural selection can act (e.g.).
References
Further reading
Axel Lange (2023) Extending the Evolutionary Synthesis: Darwin’s Legacy Redesigned. CRC Press*
External links
https://www.extendedevolutionarysynthesis.com
Biological hypotheses
Extended evolutionary synthesis | Constructive development (biology) | [
"Biology"
] | 1,306 | [
"Biological hypotheses"
] |
56,284,478 | https://en.wikipedia.org/wiki/QuEST | Quantum Entanglement Science and Technology (QuEST) is a research program, announced by the DARPA Microsystems Technology Office (MTO) in 2008. As a follow-on to the QuIST Program, its goal was to further accelerate development in the field of quantum information science.
Example areas under investigation included:
Shor's factoring algorithm,
Quantum machine learning,
Quantum game theory,
Secure quantum communications,
Quantum ghost imaging and interaction-free measurement, quantum image processing,
Remote sensing, quantum radar and quantum metrology, e.g. entanglement-assisted gravitomagnetic interferometry.
See also
IARPA – Intelligence Advanced Research Projects Agency
References
External links
QuEST Program overview (archived web page)
DARPA projects | QuEST | [
"Physics"
] | 152 | [
"Quantum mechanics",
"Quantum physics stubs"
] |
56,286,683 | https://en.wikipedia.org/wiki/NGC%20517 | NGC 517, also occasionally referred to as PGC 5214 or UGC 960, is a lenticular galaxy located approximately 188 million light-years from the Solar System in the constellation Pisces. It was discovered on 13 September 1784 by astronomer William Herschel.
Observation history
Herschel discovered the object along with NGC 515 using Beta Andromedae as a reference star. He described his discovery as "two, both stellar", indicating his misidentification of the object as a star. While Herschel only noted one position about 35" east of NGC 515, Heinrich d'Arrest made the first accurate measurement of the object, using observation data of three separate nights. The object was also observed by John Herschel, son of William Herschel and later catalogued by John Louis Emil Dreyer in the New General Catalogue, where the galaxy was described as "pretty faint, round, stellar, southeastern of 2" with the other one being NGC 515.
Description
The galaxy has an apparent visual magnitude of 12.5 and can be classified as type S0 using the Hubble Sequence. The object's distance of roughly 190 million light-years from the Solar System can be estimated using its redshift and Hubble's law.
See also
Lenticular galaxy
List of NGC objects (1–1000)
Pisces (constellation)
References
External links
SEDS
Lenticular galaxies
Pisces (constellation)
0517
5214
00960
Astronomical objects discovered in 1784
Discoveries by William Herschel | NGC 517 | [
"Astronomy"
] | 307 | [
"Pisces (constellation)",
"Constellations"
] |
56,286,748 | https://en.wikipedia.org/wiki/Olivetti%20P6066 | Olivetti P6066 was a personal computer programmable with a version of Basic owned by Olivetti and integrated in the operating system.
Description
It was identical to Olivetti P6060 in the mechanical design; however, the color (white) and performances were different.
It was an improved version of the P6060, from which it was possible to make an upgrade.
Head of the development was Pier Giorgio Perotto, and the production site was Scarmagno.
External links
Retro Computer museum, Zatec, Czech Republic video
Archivio Olivetti
Olivetti personal computers
Computer-related introductions in 1975 | Olivetti P6066 | [
"Technology"
] | 123 | [
"Computing stubs"
] |
56,288,799 | https://en.wikipedia.org/wiki/Mariel%20V%C3%A1zquez | Mariel Vázquez (born ) is a Mexican mathematical biologist who specializes in the topology of DNA. She is a professor at the University of California, Davis, jointly affiliated with the departments of mathematics and of microbiology and molecular genetics.
Education
Vázquez received her Bachelor of Science in Mathematics from the National Autonomous University of Mexico in 1995. She received her Ph.D. in mathematics from Florida State University in 2000.
Her dissertation was entitled Tangle Analysis of Site-specific Recombination: Gin and Xer Systems and her advisor was De Witt Sumners.
Career
Vázquez was a postdoctoral fellow at the University of California, Berkeley from 2000 to 2005, where she researched mathematical and biophysical models of DNA repair in human cells with Rainer Sachs as part of the mathematical radiobiology group.
She was a faculty member in the mathematics department at San Francisco State University from 2005 to 2014.
In 2014, she joined the faculty at the University of California, Davis as a CAMPOS scholar.
Awards and honors
In 2011, Vázquez received a National Science Foundation CAREER Award to research topological mechanisms of DNA unlinking.
In 2012, she was the first San Francisco State University faculty member to receive the Presidential Early Career Award for Scientists and Engineers.
She received a grant for computer analysis of DNA unknotting from the National Institutes of Health in 2013.
In 2016, she was chosen for the Blackwell-Tapia prize, which is awarded every other year to a mathematician who has made significant research contributions in their field, and who has worked to address the problem of under-representation of minority groups in mathematics.
She was selected for the inaugural class of Association for Women in Mathematics fellows in 2017. She was elected a Fellow of the American Mathematical Society in the 2020 class "for contributions in research and outreach at the interface of topology and molecular biology, and for service to the mathematical community in particular to underrepresented groups."
References
External links
The Shape of DNA - Numberphile
How DNA unties its own knots - Numberphile
Stern, Gary M. A Scientific Star. The Hispanic Outlook in Higher Education. 18 February 2013.
Living people
1970s births
Year of birth missing (living people)
Mexican mathematicians
Mexican women mathematicians
Fellows of the Association for Women in Mathematics
Mathematical and theoretical biology
University of California, Davis faculty
San Francisco State University faculty
National Autonomous University of Mexico alumni
Florida State University alumni
Fellows of the American Mathematical Society
Recipients of the Presidential Early Career Award for Scientists and Engineers | Mariel Vázquez | [
"Mathematics"
] | 492 | [
"Applied mathematics",
"Mathematical and theoretical biology"
] |
63,252,675 | https://en.wikipedia.org/wiki/Transhalogenation | Transhalogenation is a substitution reaction in which the halide of a halide compound is exchanged for another halide.
Finkelstein reaction
A common method is halide metathesis. An example is the conversion of alkyl chloride into alkyl fluoride:
C3H5-Cl + NaF → R-F + NaCl
This kind of reaction is called Finkelstein reaction. However, it is also possible, for example, to produce phosphorus fluoride compounds by transhalogenating chlorine, bromine or iodine bound to phosphorus with a metal fluoride.
Details and biological use
As a halogen source for transhalogenation, metal halides (such as sodium fluoride or lithium fluoride) are often used, but also the use of onium halides is possible. Transhalogenation has been described as a gentle method for the synthesis of fluoroorganylboranes. It is also possible to produce aryliodides from the corresponding aryl chlorides or aryl bromides.
One investigation showed a possibility to perform transhalogenation by means of genetically modified enzymes (haloalkanes dehalogenases, HLDs).
Literature
References
Chemical reactions | Transhalogenation | [
"Chemistry"
] | 258 | [
"nan"
] |
63,253,311 | https://en.wikipedia.org/wiki/Jeff%20Sebo | Jeffrey Raymond Sebo (born February 24, 1983) is an American philosopher. He is clinical associate professor of environmental studies, director of the animal studies MA program, and affiliated professor of bioethics, medical ethics, and philosophy at New York University. In 2022, he published his first sole-authored book, Saving Animals, Saving Ourselves.
Early life and education
Sebo is the son of Sheryl L. Sebo, an organist, and Eric J. Sebo, a systems special operations manager, of Plano, Texas. He studied philosophy and sociology at Texas Christian University, graduating summa cum laude with a BA in 2005. In the same year, he published his first academic article, "A Critique of the Kantian Theory of Indirect Duties to Animals," in Animal Liberation Philosophy & Policy. During his studies, he founded two animal rights groups in Fort Worth, Texas, one that hosted movie nights and ran leafletting campaigns and another that facilitated care for feral cats. Sebo completed his PhD at New York University in 2011. His dissertation, The Personal Is Political, was supervised by Derek Parfit, John Richardson, Sharon Street, and J. David Velleman (chair of the committee).
Career
After graduating, Sebo took a postdoc at New York University (NYU) in animal and environmental studies until 2014, when he took up a one-year postdoctoral position in bioethics with the National Institutes of Health. From 2015 to 2017, Sebo worked as a research assistant professor of philosophy at University of North Carolina at Chapel Hill, where he was the associate director of the Parr Center for Ethics at the university. He returned to NYU in 2017 as a clinical assistant professor in environmental studies, with affiliate roles in bioethics, medical ethics, and philosophy. He directs the university's animal studies MA programme.
Sebo has been a board member of Minding Animals International since 2014, a mentor and contributing writer at Sentient Media from 2020 and a senior research affiliate at the Legal Priorities Project since 2021; he was an executive committee member of the Animals & Society Institute from 2012 to 2020, board member of Animal Charity Evaluators from 2015 to 2021 and an advisory member of the Sentience Institute from 2018 to 2020.
In 2018, Sebo co-authored Food, Animals and the Environment: An Ethical Approach, a book devoted to food ethics, with Christopher Schlottmann. In the same year, Sebo was among those filing an amicus brief in support of granting legal personhood to chimpanzees. Chimpanzee Rights: The Philosopher's Brief was published by Routledge in 2018; Sebo was one of 13 authors, along with Kristin Andrews, Gary L Comstock, G. K. D. Crozier, Sue Donaldson, Andrew Fenton, Tyler M. John, L. Syd M. Johnson, Robert C. Jones, Will Kymlicka, Letitia Meynell, Nathan Nobis, and David Pena-Guzman.
In 2020, Sebo was promoted to clinical associate professor. His first sole-authored book, Saving Animals, Saving Ourselves, was published by Oxford University Press in 2022. In 2024, Sebo, along with Jonathan Birch and Kristin Andrews, launched the New York Declaration on Animal Consciousness. His second sole-authored book, The Moral Circle: Who Matters, What Matters, and Why, is forthcoming, published by Norton.
Sebo was included in Vox's 2024 "Future Perfect 50", a list highlighting individuals making significant contributions to a better future.
Personal life
In 2014, Sebo married Maryse Mitchell-Brody, a psychotherapist, in a ceremony officiated by a Universal Life minister. The couple lived together in Brooklyn, New York, with their dog Smoky until their separation in 2022.
Selected publications
References
External links
In Conversation with Jeff Sebo: How to Prevent Future Pandemics (video)
Sebo, Jeff (7 April 2018). "Should Chimpanzees Be Considered Persons?". The New York Times.
1983 births
Living people
21st-century American philosophers
American animal rights scholars
American ethicists
American male non-fiction writers
American political philosophers
Animal ethicists
Environmental ethicists
Medical ethicists
New York University alumni
New York University faculty
People associated with effective altruism
Philosophers from Texas
Texas Christian University alumni
Writers from Texas
21st-century American male writers
American bioethicists | Jeff Sebo | [
"Environmental_science"
] | 905 | [
"Environmental ethicists",
"Environmental ethics"
] |
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