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63,627,497 | https://en.wikipedia.org/wiki/NGC%201357 | NGC 1357 is an isolated spiral galaxy situated in constellation of Eridanus. Located about 92 million light years away, it is a member of the Eridanus cluster of galaxies, a cluster of about 200 galaxies, being the farthest known member. Based on location and distance, NGC 1357 is located at the very edge on the Eridanus Cluster. It was discovered by William Herschel on February 1, 1785.
Characteristics
NGC 1357 has a Hubble classification of Sab, which indicates it is a spiral galaxy with no bar. It is moving away from the Milky Way at a rate of 2,018 km/s. Its size on the night sky is 3.2' x 2.4' which is proportional to its real size of the 85 000 ly.
NGC 1357's surface brightness profile shows a small bulge and a large, fairly exponential disk. However, the automatic bulge-disk fit would give an unreliably large bulge extending through the whole galaxy (lowermost row). A more reasonable fit is obtained by adding another exponential disk component to the inner part of the galaxy (upper profile). This inner component corresponds to the region of tightly wound spiral arms with higher surface brightness.
Analysis of the NGC 1357's spectra revealed the ionised calcium.
References
External links
Eridanus (constellation)
Unbarred spiral galaxies
1357
013166
Eridanus Group | NGC 1357 | [
"Astronomy"
] | 289 | [
"Eridanus (constellation)",
"Constellations"
] |
63,628,505 | https://en.wikipedia.org/wiki/Insensible%20perspiration | Insensible perspiration, also known as transepidermal water loss, is the passive vapour diffusion of water through the epidermis. Insensible perspiration takes place at an almost constant rate and reflects evaporative loss from the epithelial cells of the skin. Unlike sweating, the lost fluid is pure without additional solutes. For this reason, it can also be referred to as "insensible water loss".
The amount of water lost in this way is deemed to be approximately per day. Some sources broaden the definition of insensible perspiration to include not only the water lost through the skin, but also the water lost through the epithelium of the respiratory tract, which is also approximately per day.
Insensible perspiration is the main source of heat loss from the body, with the figure being placed around 480 kCal per day, which is approximately 25% of basal heat production. Insensible perspiration is not under regulatory control.
History
Known in Latin as , the concept was already known to Galen in ancient Greece and was studied by the Venetian Santorio Santorio, who experimented on himself and observed that a significant part of the weight of what he ate and drank was not excreted in his faeces or urine but was also not being added to his body weight. He was able to measure the loss through a chair that he designed.
References
Excretion | Insensible perspiration | [
"Biology"
] | 300 | [
"Excretion"
] |
63,628,978 | https://en.wikipedia.org/wiki/IC%201953 | IC 1953 is a barred spiral galaxy situated in the constellation of Eridanus. Located about 83.4 million light years away, it is a member of the Eridanus cluster of galaxies, a cluster of about 200 galaxies. It was discovered by DeLisle Stewart in 1899.
IC 1953 has a Hubble classification of SB(rs)d, which indicates it is a barred spiral galaxy. It is moving away from the Milky Way at a rate of 1,867 km/s. Its size in the night sky is 2.9' x 2.1', which is proportional to its estimated size of 88,000 ly.
NGC 1395 Group
IC 1953 is part of the NGC 1395 group (also known as LGG 97), which includes at least 31 members, including: NGC 1315, NGC 1325, NGC 1331, NGC 1332, NGC 1347, NGC 1353, NGC 1371, NGC 1377, NGC 1385, NGC 1395, NGC 1401, NGC 1414, NGC 1415, NGC 1422, NGC 1426, NGC 1438, NGC 1439, IC 1952, and IC 1962. This group is also part of the Eridanus Cluster.
References
Eridanus (constellation)
Barred spiral galaxies
1953
Eridanus Group
548-038
03314-2138
UGCA objects
-04-09-026
013184 | IC 1953 | [
"Astronomy"
] | 293 | [
"Eridanus (constellation)",
"Constellations"
] |
63,629,156 | https://en.wikipedia.org/wiki/NGC%201369 | NGC 1369 is a barred lenticular galaxy located 59 million light years away in constellation of Eridanus. The galaxy was discovered by astronomer Julius Schmidt on January 19, 1865, and is a member of the Fornax Cluster. NGC 1369 is a host to a supermassive black hole with an estimated mass of 1.8 million solar masses.
Surrounding NGC 1369 is a population of a least 11 known globular clusters.
Physical characteristics
In the disk of NGC 1369, there are two bright, diffuse spiral arms which break of a relatively weak bar structure. These arms quickly fade in the diffuse outer disk. Despite the presence of spiral arms, the galaxy is very red which actually makes NGC 1369 a lenticular galaxy. Also, the galaxy is devoid of atomic and molecular gas, and does not show any indications of ionised-gas emission as a result of star formation. Observations in X-rays have shown that it is infalling in a transional region of the Fornax Cluster between the high and low-density regions of the cluster where the X-ray emission is still present. As a result, ram-pressure stripping would have acted to stop star formation once the galaxy entered into the cluster core, causing it to transion from a spiral galaxy to a lenticular galaxy.
See also
List of NGC objects (1001–2000)
NGC 1386
External links
References
1369
013330
Eridanus (constellation)
Astronomical objects discovered in 1865
Barred lenticular galaxies
Fornax Cluster | NGC 1369 | [
"Astronomy"
] | 308 | [
"Eridanus (constellation)",
"Constellations"
] |
63,629,904 | https://en.wikipedia.org/wiki/Metabolomics%20%28journal%29 | Metabolomics is a peer-reviewed scientific journal covering topics including whole metabolome analysis of organisms, metabolite target analysis, with applications within animals, plants and microbes, pharmacometabolomics for precision medicine, as well as systems biology. It is published by Springer Science+Business Media and the current editor-in-chief is Roy Goodacre.
The 2018 impact factor was 3.167.
References
Academic journals established in 2005
English-language journals
Metabolomics journals | Metabolomics (journal) | [
"Chemistry"
] | 102 | [
"Biochemistry stubs",
"Biochemistry journal stubs"
] |
63,630,157 | https://en.wikipedia.org/wiki/Phonurgia%20Nova | Phonurgia Nova ("New Science of Sound Production") is a 1673 work by the Jesuit scholar Athanasius Kircher. It is notable for being the first book ever dedicated entirely to the science of acoustics, and for containing the earliest description of an aeolian harp. It was dedicated to the Holy Roman Emperor Leopold I and printed in Kempten by Rudoph Dreherr.
Purpose and argument
Kircher was prompted to write the work because Samuel Morland had published a claim to have invented the speaking trumpet. Kircher wished to defend his own priority in this invention, asserting that he had used a "tuba stentorophonica" for many years at the shrine of Saint Eustace at the :it:Santuario della Mentorella to broadcast calls for the faithful to come to mass. As evidence he referred to his own work Musurgia Universalis, published in 1650.
The work is divided in two books. The first, the Phonosophia anacamptica offered a detailed examination of the phenomenon of the echo. He expounded his theory that sound moved in waves, bouncing off surfaces like light off a mirror; indeed the first chapter opens with the maxim “Sonus lucis simia est” (“sound is like light”). He also described the use of various designs of tube to pick up and amplify sound. As he developed his argument, Kircher described various devices of his own invention including speaking statues, musical instruments with internal mechanisms that generated unexpected harmonies, and the aeolian harp. The second book, Phonosophia nova discussed the influence of music on the human mind, and the therapeutic use of music. Among other things he looked in detail at tarantism.
Illustrations
The frontispiece of the work depicts, at the top, a choir and orchestra of angels gathered around a pyramid representing the Holy Trinity. Beneath them an allegorical figure of Fame flies across the heavens blowing her trumpet and carrying a banner proclaiming "Canit inclyta caeseris arma" ("She proclaims the Emperor's illustrious arms"). On the left sits Apollo surrounded by the nine Muses on Mount Parnassus and below then Pan leads a group celebrating a bacchanalia. On the right a group of tritons escort Poseidon across the sea, kettledrums and trumpets accompany a cavalry charge, and a huntsman blows his horn while chasing deer. In the centre the figure standing appears to be Fame once again, standing on a pedestal blowing a horn. She also holds a trumpet, into which putti are blowing from above, while beneath them a man speaks into a tube while facing the surface of the pedestal. An echo, denoted by a dotted line, carries the sound from the pedestal to the ear of a man reclining at the bottom of the illustration.
The original artwork for the portrait of Emperor Leopold I was by Franz Georg Hermann and the frontispiece was by Felix Cheurier. The engravings for both were undertaken by Georg Andreas Wolfgang the Elder.
External links
digital copy of Phonurgia Nova
References
Acoustics
1673 works
1673 in science
Athanasius Kircher | Phonurgia Nova | [
"Physics"
] | 656 | [
"Classical mechanics",
"Acoustics"
] |
63,630,286 | https://en.wikipedia.org/wiki/HII%20galaxy | An HII galaxy is a very luminous dwarf starburst galaxy. Generally, HII galaxies have a low metallicity and high percentage of neutral hydrogen. There is generally believed to be a relationship between luminosity and disturbed morphology, suggesting that the starburst activity in the galaxy is caused by tidal interactions. The distribution of luminosities tends to cluster around two different extremes: those with a high luminosity and highly disturbed morphology, and those with a low luminosity and fairly regular and symmetric morphology. Those with high luminosities are labelled by some as type I HII galaxies and those with lower luminosities as type II HII galaxies. There is also a general correlation between metallicity and mass of the galaxies. The name of HII galaxies comes from their spectroscopic properties which are more or less indistinguishable from that of HII regions.
References
Starburst galaxies | HII galaxy | [
"Astronomy"
] | 190 | [
"Galaxy stubs",
"Astronomy stubs"
] |
63,630,797 | https://en.wikipedia.org/wiki/Spirit%20of%20Wood%20Architecture%20Award | The Spirit of Nature Wood Architecture Award was an international architecture award, awarded every two years, from 2000 until 2012, when it was discontinued. The award was founded by the Wood in Culture Association (Puu kulttuurissa ry), a Finnish association sponsored by the Finnish wood industry. The award is given to a person or group of persons whose work exemplifies a progressive and creative use of wood. The prize money was €40,000. The award was made at a ceremony held at the Sibelius Hall in the city of Lahti. The award was given a total of seven times. A few of the award winners afterwards received commissions to design a small structure in Lahti.
Recipients of the Spirit of Nature Wood Architecture Award
Structures in Lahti designed by Spirit of Nature Wood Architecture Award recipients
See also
List of architecture awards
References
Architecture awards
Awards established in 2000 | Spirit of Wood Architecture Award | [
"Engineering"
] | 182 | [
"Architecture stubs",
"Architecture"
] |
63,631,543 | https://en.wikipedia.org/wiki/Introduction%20to%203-Manifolds | Introduction to 3-Manifolds is a mathematics book on low-dimensional topology. It was written by Jennifer Schultens and published by the American Mathematical Society in 2014 as volume 151 of their book series Graduate Studies in Mathematics.
Topics
A manifold is a space whose topology, near any of its points, is the same as the topology near a point of a Euclidean space; however, its global structure may be non-Euclidean. Familiar examples of two-dimensional manifolds include the sphere, torus, and Klein bottle; this book concentrates on three-dimensional manifolds, and on two-dimensional surfaces within them. A particular focus is a Heegaard splitting, a two-dimensional surface that partitions a 3-manifold into two handlebodies. It aims to present the main ideas of this area, but does not include detailed proofs for many of the results that it states, in many cases because these proofs are long and technical.
The book has seven chapters. The first two are introductory, providing material about manifolds in general, the Hauptvermutung proving the existence and equivalence of triangulations for low-dimensional manifolds, the classification of two-dimensional surfaces, covering spaces, and the mapping class group. The third chapter begins the book's material on 3-manifolds, and
on the decomposition of manifolds into smaller spaces by cutting them along surfaces. For instance, the three-dimensional Schoenflies theorem states that cutting Euclidean space by a sphere can only produce two topological balls; an analogous theorem of J. W. Alexander states that at least one side of any torus in Euclidean space must be a solid torus. However, for more complicated manifolds, cutting along incompressible surfaces can be used to construct the JSJ decomposition of a manifold. This chapter also includes material on Seifert fiber spaces. Chapter four concerns knot theory, knot invariants, thin position, and the relation between knots and their invariants to manifolds via knot complements, the subspaces of Euclidean space on the other sides of tori.
Reviewer Bruno Zimmermann calls chapters 5 and 6 "the heart of the book", although reviewer Michael Berg disagrees, viewing chapter 4 on knot theory as more central. Chapter 5 discusses normal surfaces, surfaces that intersect the tetrahedra of a triangulation of a manifold in a controlled way. By parameterizing these surfaces by how many pieces of each possible type they can have within each tetrahedron of a triangulation, one can reduce many questions about manifolds such as the recognition of trivial knots and trivial manifolds to questions in number theory, on the existence of solutions to certain Diophantine equations. The book uses this tool to prove the existence and uniqueness of prime decompositions of manifolds. Chapter 6 concerns Heegaard splittings, surfaces which split a given manifold into two handlebodies. It includes the theorem of Reidemeister and Singer on common refinements ("stabilizations") of Heegaard splittings, the reducibility of splittings, the uniqueness of splittings of a given genus for Euclidean space, and the Rubinstein–Scharlemann graphic, a tool for studying Heegaard splittings.
A final chapter surveys more advanced topics including the geometrization conjecture, Dehn surgery, foliations, laminations, and curve complexes.
There are two appendices, on general position and Morse theory.
Audience and reception
Although written in the form of an introductory-level graduate textbook, this book presents many recent developments, making it also of interest to specialists in this area. A small amount of background in general topology is needed, and additional familiarity with algebraic topology and differential geometry could be helpful in reading the book. Many illustrations and exercises are included.
Reviewer Bruno Zimmermann states that the book "is written in a nice and intuitive way which makes it pleasant to read". Reviewer Michael Berg calls it "an excellent book that richly illustrates the scope of her chosen subject ... very well written, clear and explicit in its presentation".
Related reading
Other related books on the mathematics of 3-manifolds include 3-manifolds by John Hempel (1976), Knots, links, braids and 3-manifolds by Victor V. Prasolov and Alexei B. Sosinskiĭ (1997), Algorithmic topology and classification of 3-manifolds by Sergey V. Matveev (2nd ed., 2007), and a collection of unpublished lecture notes on 3-manifolds by Allen Hatcher.
References
Geometric topology
Mathematics books
2014 non-fiction books
Publications of the American Mathematical Society | Introduction to 3-Manifolds | [
"Mathematics"
] | 944 | [
"Topology",
"Geometric topology"
] |
63,632,458 | https://en.wikipedia.org/wiki/Praseodymium%28III%29%20fluoride | Praseodymium(III) fluoride is an inorganic compound with the formula PrF3, being the most stable fluoride of praseodymium.
Preparation
The reaction between praseodymium(III) nitrate and sodium fluoride will obtain praseodymium(III) fluoride as a green crystalline solid:
Pr(NO3)3 + 3 NaF → 3 NaNO3 + PrF3
There are also literature reports on the reaction between chlorine trifluoride and various oxides of praseodymium (Pr2O3, Pr6O11 and PrO2), where praseodymium(III) fluoride is the only product. The reaction between bromine trifluoride and praseodymium oxide left in the air for a period of time also produces praseodymium(III) fluoride, but the reaction is incomplete; the reaction between praseodymium(III) oxalate hydrate and bromine trifluoride can obtain praseodymium(III) fluoride, and carbon is also produced from this reaction. Praseodymium(III) fluoride can also be obtained by reacting praseodymium oxide and sulfur hexafluoride at 584 °C.
Properties
Physical
Praseodymium(III) fluoride forms pale green crystals of trigonal system (or hexagonal system), space group P 3c1, (or P 6/mcm), cell parameters a = 0.7078 nm, c = 0.7239 nm, Z = 6, structure like cerium(III) fluoride (CeF3).
Chemical
Praseodymium(III) fluoride is a green, odourless, hygroscopic solid that is insoluble in water.
Uses
Praseodymium(III) fluoride is used as a doping material for laser crystals.
See also
Praseodymium(III) chloride
Praseodymium(IV) fluoride
References
Fluorides
Praseodymium(III) compounds
Inorganic compounds
Lanthanide halides | Praseodymium(III) fluoride | [
"Chemistry"
] | 461 | [
"Fluorides",
"Inorganic compounds",
"Salts"
] |
76,711,561 | https://en.wikipedia.org/wiki/Parking%20function | Parking functions are a generalization of permutations studied in combinatorics, a branch of mathematics.
Definition and applications
A parking function of length is a sequence of positive integers, each in the range from 1 to , with the property that, for every up to the sequence length, the sequence contains at least values that are at most . That is, it must contain at least one 1, at least two values that are 1 or 2, at least three values that are 1, 2, or 3, etc. Equivalently, if the sequence is sorted, then for each in the same range, the th value of the sorted sequence is at most .
For instance, there are 16 parking functions of length three:
(1,2,3), (2,3,1), (3,1,2),
(3,2,1), (2,1,3), (1,3,2),
(1,1,2), (1,2,1), (2,1,1),
(1,1,3), (1,3,1), (3,1,1),
(1,2,2), (2,1,2), (2,2,1),
(1,1,1).
The name is explained by the following thought experiment. A sequence of drivers in cars travel down a one-way street having parking spaces, with each driver having a preferred parking space. Each driver travels until reaching their preferred space, and then parks in the first available spot. A parking function describes preferences for which all cars can park. For instance, the parking function (2,1,2,1) describes preferences for which the first and third drivers both prefer the second space, while the other two drivers both prefer the first space. The first driver parks in space 2, the second in space 1, and the third in space 3 (because space 2 is taken). The fourth driver starts looking for a free space at space 1, but doesn't find it until space 4; all previous spaces were taken. The sequence (3,3,1,3) is not a parking function: too many drivers prefer space 3, so the last driver starts looking for a space after already passing the only free space, and will be unable to park.
Parking functions also have a more serious application in the study of hash tables based on linear probing, a strategy for placing keys into a hash table that closely resembles the one-way parking strategy for cars.
Combinatorial enumeration
The number of parking functions of length is exactly For instance for this number is .
John Riordan credits to Henry O. Pollak the following argument for this formula. On a circular one-way road with spaces, each of cars will always be able to park, no matter what preference each driver has for their starting space. There are choices for the preferences, each of which leaves one vacant space. All spaces are symmetric to each other, so by symmetry, there are choices for preferences that leave space as the vacant space. These choices are exactly the parking functions. The parking functions can also be placed in bijection with the spanning trees on a complete graph with vertices, one of which is designated as the root. This bijection, together with Cayley's formula for the number of spanning trees, again shows that there are parking functions.
Much research has studied the number of parking functions of a special form. As a very simple special case, the parking functions that allow each car to park in its own preferred spot are exactly the permutations, counted by the factorials. The parking functions that allow each car to park either in its preferred spot or in the next spot are counted by the ordered Bell numbers.
References
Factorial and binomial topics | Parking function | [
"Mathematics"
] | 787 | [
"Factorial and binomial topics",
"Combinatorics"
] |
76,712,006 | https://en.wikipedia.org/wiki/NGC%202491 | NGC 2491 is a spiral galaxy located in Canis Minor constellation. It is located 580 million light-years from Earth and has an approximate diameter of 130,000 light-years.
Details
NGC 2491 was discovered by American astronomer Lewis Swift on November 15, 1885. Swift described it as extremely faint, small, with a round irregular shape, and a bright star to the west. With a surface brightness of magnitude of 11.75, NGC 2491 is classified as a high surface brightness galaxy.
References
2491
Spiral galaxies
Canis Minor
022353
022353
Discoveries by Lewis Swift
Astronomical objects discovered in 1885 | NGC 2491 | [
"Astronomy"
] | 125 | [
"Canis Minor",
"Constellations"
] |
76,712,083 | https://en.wikipedia.org/wiki/NGC%202485 | NGC 2485 is a spiral galaxy located in the constellation of Canis Minor. It is located 233 million light-years away from Earth and has an estimated diameter of 110,000 light-years. NGC 2485 was discovered on March 25, 1864, by Albert Marth and has an approximate surface magnitude of 13.08.
References
Spiral galaxies
Canis Minor
2485
04112
022266
022266
Astronomical objects discovered in 1864
Discoveries by Albert Marth
07541+0736
+01-21-001 | NGC 2485 | [
"Astronomy"
] | 107 | [
"Canis Minor",
"Constellations"
] |
76,712,259 | https://en.wikipedia.org/wiki/NGC%202494 | NGC 2494 is a barred lenticular galaxy located in the Monoceros constellation. It is 183 million light-years away and about 58,000 light-years in diameter.
Details
NGC 2494 was discovered on February 6 in 1864 by Albert Marth who listed it as NGC 2494. Subsequently, on February 3, 1888, it was observed again by Lewis Swift who gave it the designation as IC 487. It has a broad H II region and a magnitude brightness of 12.60.
References
Barred lenticular galaxies
Monoceros
2494
IC objects
04141
22377
IRAS catalogue objects
2MASS objects
Discoveries by Albert Marth
Astronomical objects discovered in 1864
+00-21-001
22377 | NGC 2494 | [
"Astronomy"
] | 147 | [
"Monoceros",
"Constellations"
] |
76,712,655 | https://en.wikipedia.org/wiki/Dimesityldioxirane | Dimesityldioxirane is a substituted dioxirane with two mesityl groups attached to the dioxirane carbon. It is a colorless crystalline substance stable in its solid state around -20 °C.
Structure
The molecule possesses approximately C2 symmetry and the mesityl groups are twisted by 54.2°. The bulky mesityl groups cause steric strain which is reduced by increase in R1–C–R2 angle from 117° in dioxirane to 119.2° in dimesityldioxirane. The mesityl groups also rotate about the single bond, consequently reducing steric repulsions further.
Synthesis and Uses
Dimesityldioxirane was first isolated at room temperature in pure as well as in solution form in 1994. It was synthesised by irradiation of its diazo derivative in trichlorofluoromethane at 183K to form , followed by oxidation. The synthesis had a yield of 50%.
It can mainly be used as an oxidizing agent but is less oxidizing than other dioxiranes due to its stability.
See also
Difluorodioxirane
Dimethyldioxirane
Shi epoxidation
References
Dioxiranes
Organic peroxides
Oxidizing agents | Dimesityldioxirane | [
"Chemistry"
] | 262 | [
"Organic compounds",
"Redox",
"Oxidizing agents",
"Organic peroxides"
] |
76,715,531 | https://en.wikipedia.org/wiki/GooseEgg | GooseEgg is the name used by Microsoft to describe an exploit tool used by the Russian hacking group Forest Blizzard (also known as Fancy Bear and other names) to exploit CVE-2022-38028, a software vulnerability in Microsoft Windows. The vulnerability is a flaw in the Windows print spooler that grants high privilege access to an attacker.
In April 2024, it was revealed that CVE-2022-38028 had for some time been being exploited in an ongoing cyberattack program. While Microsoft had patched the vulnerability in 2022, they did not disclose at the time that it had been being actively exploited since at least 2020, and possibly earlier.
References
Privilege escalation exploits | GooseEgg | [
"Technology"
] | 145 | [
"Computer security stubs",
"Computing stubs",
"Privilege escalation exploits",
"Computer security exploits"
] |
76,715,889 | https://en.wikipedia.org/wiki/Property%20graph |
Property Graphs
The data model of "property graphs" , "labeled property graphs ", or "attributed graphs " has emerged since the early 2000s as a common denominator of various models of graph-oriented databases. It can be defined informally as follows:
In computer science terms, a property graph is a data structure representing entities associated by directed relationships, where the nodes and relations can both include multiple attributes / properties
In terms of graph theory, a property graph is a directed multigraph, whose vertices/nodes represent the entities of the corresponding data structure
Properties take the form of key-value pairs, as used for example in JSON. Keys are defined by character strings. Values are either numeric or also character strings. These properties fall within the usual definition of attributes as understood in entity-attribute-value or object-oriented modeling. This is why the phrase "attributed graph" is relevant. Unlike what is the case with RDF graphs, properties are not arcs of the graph proper. This is another reason why it would be preferable to call them attributed graphs, or graphs with properties, rather than "property graphs", which is misleading.
Relationships are represented by arcs of the graph. These are often called edges, even though, strictly speaking, edges belong in undirected graphs. Arcs must have an identifier, a source node and a target node, and may have one or more attributes/properties in the previous sense
Formal definition
Building upon widely adopted definitions, a property graph/attributed graph can be defined by a 7-tuple (N, A, P, V, α, , π), where
N is the set of nodes /vertices of the graph
A is the set of arcs (directed edges) of the graph
K is a set of keys, taken from a countable set, defining the nature of attributes/properties
V is a set of values, to be associated with these keys in order to define full-fledged attributes
is a total function, defining the multigraph proper. For a ∈ A, u∈ N, v ∈ N, α (a) = (u, v) means that a is an arc of the graph having node u for origin and node v for target
is a binary relation over (A∪N) and K (formally defined as a subset of the cartesian product (A∪N)×K ), associating zero, one or several keys to each arc and node of the graph
is a partial function, providing values for the properties of the nodes and the arcs which include them. For u ∈ N, a ∈ A and k ∈ K, π (u, k) (respectively π (a, k)) is the value associated with the property key k for the node u, (respectively the arc a), if the corresponding attribute property is defined there.
A complementary construct, used in several implementations of property graphs with commercial graph databases, is that of labels, which can be associated both with nodes and arcs of the graph. Labels have a practical rather than theoretical justification, as they were originally intended for users of Entity-Relationship models and relational databases, to facilitate the import of their legacy data sets into graph databases :. labels make it possible to associate the same identifier (that of the relational table, or of the ER entity) to all graph nodes which would correspond to the different rows of this relational table, or to instances of the same generic entity / class. With the proposed definition, these labels could in fact be viewed as attributes defined only by a key, without an associated value (this is why is defined separately as a binary relation, and π as a partial function). The basic definition thus becomes much clearer, simpler, and satisfies a principle of parsimony. Alternatively, and more consistently, labels can be defined through type graphs, as special types associated with nodes and arcs.
Relations with other models
Graph theory and classical graph algorithmics
Attributed graphs, as defined above, are especially useful and relevant in that they provide an "umbrella" hypernymic concept ( i.e. common generalization) for several key graph-theoretic models, which have long-since been widely used in classical graph algorithms
Labeled graphs associate labels to each vertex and/or edge of a graph. Matched with attributed graphs, these labels would correspond to attributes comprising only a key, taken from a countable set (typically a character string, or an integer)
Colored graphs, as used in classical graph coloring problems, are but special cases of labeled graphs, whose labels are defined on a finite set of keys, matched to colors.
Weighted graphs associate a numerical value to arcs/edges, and, when relevant, to the vertices of a directed or undirected graph. These weights/valuations would correspond to the differents values of a set of attributes with the same key. As an example, for a graph modeling a road network, we could have a set of weights corresponding to the capacities (measured in number of vehicles per unit of time), and another representing the distances, these two valuations being associated with each road segment represented by an edge of the graph, and differentiated by two corresponding keys.
Flow networks are weighted graphs whose weights are interpreted as a capacities. They are used in all kinds of very classical models of transport networks, used e.g. with maximum flow algorithms.
Shortest path problems, as solved by very classical algorithms (like Dijkstra's algorithm), operate on weighted graphs for which the weights correspond to distances, real or virtual.
Knowledge graphs and RDF graphs
Knowledge graphs, usually represented as RDF graphs, are in fact hybrid labeled graphs, whose node labels correspond to instance identifiers (IRI)s or literals, and edge labels identify types (not instances) of predicates. They have now acquired a visibility which tends to obscure the longer-established use of graphs as direct model for systems of all kinds. Attributed graphs are, by their versatility and expressivity, the best-adapted for this type of modeling, where graphs which can rightly be called cyber-physical do not merely capture weakly structured about a physical system, as would be the case with a knowledge graph, but attempt to directly capture the structure of a physical system, as matched by the connectivity structure of the graph. In contrast, an RDF graph would mix structural relationships with attached properties, and category / class information with instance / individuals, drowning out the structure The expressivity of attributed graphs, on the level of higher order logic, is also far above that of RDF graphs, which is limited to first order logic. Properties of relationships, which are at the heart of the attributed graph model, require a very cumbersome reification process to be expressed in RDF.
Standardization
NGSI-LD
The NGSI-LD data model specified by ETSI has been the first attempt to standardize property graphs under a de jure standards body.
Compared to the basic model defined here, the NGSI-LD meta-model adds a formal definition of basic categories (entity, relation, property) on the basis of semantic webstandards (OWL, RDFS, RDF), which makes it possible to convert all data represented in NGSI-LD into RDF datasets, through JSON-LD serialization. NGSI-LD entities, relations and properties are thus defined by reference to types which can themselves be defined by reference to ontologies, thesauri, taxonomies or microdata vocabularies, for the purpose of ensuring the semantic interoperability of the corresponding information.
GQL
The ISO/IEC JTC1/SC32/WG3 group of ISO, which established the SQL standard, is in the process of specifying a new query language suitable for graph-oriented databases, called GQL (Graph Query Language). This standard will include the specification of a property graph data model, which should be along the lines of the basic model described here, possibly adding notions of labels, types, and schemas .
Type graphs and schemas
Graph-oriented databases are, compared to relational databases, touted for not requiring the prior definition of a schema to start populating the base. This is desirable and suitable for environments and applications where one operates under an open world assumption, such as the description of complex systems and systems of systems, characterized by bottom-up organization and evolution, not control of a single stakeholder. However, even in such environments, it may be needed to constrain the representation of specific subsets of the information entered into the database, in a way that may resemble a traditional database schema, while keeping the openness of the overall graph for addition of unforeseen data or configurations. For example, the description of a smart city falls under the open world assumption and will be described by the upper level of a graph database, without a schema. However, specific technical sub-systems of this city remain top-down closed-world systems managed by a single operator, who may impose a stronger structuring of information, as customarily represented by a schema.
The notions of "type graphs" and schemas make it possible to meet this need, with types playing a role similar to that of labels in classical graph databases, but with the added possibility of specifying relations between these types and constraining them by keys and properties. The type graph is itself a property graph, linked by a relation of graph homomorphism with the graphs of instances that use the types it defines, playing a role similar to that of a schema in a data definition language.
The ontologies, thesauri or taxonomies used to reference NGSI-LD types are also defined by graphs, but these are RDF graphs rather than property graphs, and they typically have broader scopes than database schemas. The complementary use, possible with NGSI-LD types, of type graphs and referencing of external ontologies, makes it possible to enforce strong data structuration and consistency, while affording semantic grounding and interoperability.
References
Graph databases
Extensions and generalizations of graphs | Property graph | [
"Mathematics"
] | 2,064 | [
"Graph databases",
"Mathematical relations",
"Graph theory",
"Extensions and generalizations of graphs"
] |
76,718,150 | https://en.wikipedia.org/wiki/Hetrombopag | Hetrombopag (also known as rafutrombopag; trade name Hengqu) is a pharmaceutical drug for the treatment of thrombocytopenia and anemia.
It is a non-peptide small‐molecule thrombopoietin receptor agonist.
In China, it is approved for second-line treatment for primary immune thrombocytopenic purpura (ITP) and severe aplastic anemia (SAA) in adults.
References
Drugs acting on the cardiovascular system
Hydrazones
Pyrazolones
Phenols
Tetralins
Furans
Carboxylic acids | Hetrombopag | [
"Chemistry"
] | 130 | [
"Carboxylic acids",
"Hydrazones",
"Functional groups"
] |
76,718,163 | https://en.wikipedia.org/wiki/Katsuhiko%20Hayashi | is a Japanese reproductive geneticist and stem cell researcher. He achieved same-sex reproduction of male mice and thus ranked Nature's 10. He has been studying the mechanism by which germ cells that transmit genetic information to the next generation are produced. In particular, he has identified the molecules and environmental factors that control the differentiation process of the oocyte lineage leading to eggs by reconstructing this process using pluripotent stem cells. Recently, based on these studies, he has been conducting research into the quality control mechanism of genetic information in the oocyte lineage and the diseases caused by its breakdown.
References
Stem cell researchers
21st-century Japanese biologists
1972 births
Living people | Katsuhiko Hayashi | [
"Biology"
] | 139 | [
"Stem cell researchers",
"Stem cell research"
] |
76,718,309 | https://en.wikipedia.org/wiki/Megaliths%20in%20the%20Netherlands | Megalithic architecture appeared in what is now the Netherlands during the Neolithic period, especially in the northeast. Megalithic structures, i.e. buildings made of large upright stones, occur in various forms and functions, mainly as burial sites, temples or menhirs (stones standing alone or in a formation). In the Netherlands, only burial complexes are known. These large stone tombs () were built between 3470 and 3250 BC by members of the Western Group of the Funnelbeaker culture (TBK) and were used until about 2760 BC. After the end of the Funnelbeaker culture in the Late Neolithic, the sites were reused by the Single Grave culture and the Bell Beaker culture during the ensuing Early Bronze Age and, to a lesser extent, into the Middle Ages.Of the original 100 megalithic tombs in the Netherlands, 54 are still preserved today. Of these, 52 are located in the province of Drenthe. Two more are in the province of Groningen, one of which has been turned into a museum. There is also a site in the province of Utrecht whose classification as a megalithic tomb is uncertain. Destroyed megalithic tombs are also known from the province of Overijssel. Most of the surviving tombs are concentrated on the Hondsrug ridge between the cities of Groningen and Emmen.
The tombs attracted the interest of researchers early on. The first paper was published in 1547. A book published in 1660 by Johan Picardt, who believed that the tombs were the constructions of giants, was widely read. Titia Brongersma carried out the first known excavation of a Dutch megalithic tomb in 1685. In 1734, the first law was passed to protect the tombs, followed by others in the 18th and 19th centuries. In 1846, Leonhardt Johannes Friedrich Janssen published the first nearly complete inventory of the tombs. In 1878, William Collings Lukis and Henry Dryden made the most accurate plans to date of many of the graves. Modern archaeological research on the megalithic tombs was initiated in 1912 by Jan Hendrik Holwerda, who completely excavated two sites. Shortly thereafter, Albert Egges van Giffen began further research. He measured all the sites, carried out numerous other excavations, and had almost all the graves restored by the 1950s. Van Giffen also developed a numbering system for the megalithic tombs that is still used today, with a capital letter for the province and a number ascending from north to south (and a lowercase letter for destroyed sites). Since 1967, there has been a museum in Borger dedicated exclusively to the megalithic tombs and their builders.
The chambers of the tombs were built of granite boulders deposited in the Netherlands during the Ice Age. The gaps between the stones were filled with dry stone made of small stone slabs. The chambers were then covered with earth. Some of the mounds also have a stone fence. Depending on whether the entrance to the chamber is on a long or narrow side, the graves are called dolmens or passage graves. Almost all sites in the Netherlands are passage graves, only one is a dolmen. The graves are similar in their basic structure but vary greatly in size. The length of the chamber ranges from 2.5 m to 20 m. Small chambers were built in all phases of construction, while larger ones were added only in later phases.
Due to the unfavorable preservation conditions, only small amounts of human bones were recovered from the graves. These were mainly cremated remains. Only very limited information is available on the age and sex of the deceased.
In contrast, the grave goods were exceedingly rich. In some graves, thousands of pottery shards were discovered, which could often be reconstructed into hundreds of vessels. Other grave goods included stone tools, jewelry in the form of beads and pendants, animal bones, and, in rare cases, bronze objects. The diverse array of vessel forms and decorations permitted the identification of multiple typological levels, thereby enabling insights to be gleaned about the construction and utilization history of the graves.
Research history
Early research (16th-18th century)
The modern study of the Dutch megalithic tombs commenced in 1547 with Anthonius Schonhovius Batavus (Antony van Schoonhove), canon of the St. Donatian's Cathedral in Bruges. In a manuscript, he referenced a passage in Tacitus' Germania in which "Pillars of Heracles" are mentioned in the land of the Frisians. Schonhovius equated these with one of the tombs near Rolde and mixed Tacitus' text with local legends. He assumed that the building material was brought here by demons who were worshipped under the name of Heracles. He also believed that the tombs were altars on which human sacrifices were performed. His text was subsequently adopted by numerous other scholars over the following decades, with the Pillars of Heracles or the "Duvels Kut" ("Devil's Cunt", another name used for the grave near Rolde according to Schonhovius) being recorded on several maps between 1568 and 1636.
It was more than a hundred years before anyone wrote about the Dutch megalithic tombs who had seen them. Johan Picardt, a native of Bentheim, worked as a pastor in Rolde and Coevorden, among other places, and was also responsible for the colonization of the bogs in the border region between Bentheim and Drenthe. In 1660, he published a three-part work on the antiquities of the Netherlands, particularly the province of Drenthe and the town of Coevorden. Picardt's views were strongly influenced by biblical stories. For example, he hypothesized that the megalithic tombs were built by giants who had migrated to Drenthe from the Holy Land via Scandinavia. This view became widespread, not least because of the impressive illustrations in Picardt's book. At the same time, before and during Picardt's lifetime, there were other (mainly German) researchers who rejected this idea and attributed the construction of the tombs to ordinary people. Picardt was also the first to provide detailed descriptions of the structure of the tombs and to mention ceramic vessels as burial objects.
The lawyer and historian Simon van Leeuwen also visited the megalithic tombs in the province of Drenthe a few years after Picardt and dedicated a section to them in his work Batavia Illustrata, published posthumously in 1685. Van Leeuwen also considered the possibility of giants as builders, but thought more of tall Cimbri and Celts.
Titia Brongersma, a poet from Dokkum, conducted the inaugural known excavation of a megalithic tomb in the Netherlands in 1685. In collaboration with her cousin Jan Laurens Lentinck, the Schultheiß of Borger, she spearheaded the investigation of the Borger megalithic tomb (D27). Brongersma herself only published two poems about it, from which it emerges that she believed the grave was a temple dedicated to nature. However, she discussed this intensively with her friend Ludolph Smids, a doctor and poet from Groningen. Smids initially wrote a poem about the excavation. He published these poems in his work Poëzije in 1694 and also added a more detailed description of the finds and discoveries from the grave. Smids' publication of the excavation in Borger and his correspondence with Christian Schlegel led to the idea of giants as the builders of the megalithic tombs being increasingly rejected. However, Smids himself revised his views again after his conversion from Catholicism to Calvinism and again took up Picardt's views in his work Schatkamer der Nederlandse oudheden, published in 1711.
In 1706, Johannes Hofstede and Abraham Rudolph Kymmel conducted another excavation at a large stone tomb in Rolde (D17). In his report, Hofstede described the different layers within the site and the stratigraphic position of the pottery found. Unfortunately, the report did not influence Hofstede's contemporaries, as it was not published until 1848.
In the 1730s, new levees were constructed in significant portions of the Netherlands and northwest Germany, replacing the previous ones, which were based on wooden structures that had been damaged by imported shipworms. The new dikes consisted of stone-covered earth mounds, which is why erratic blocks became a highly sought-after building material. The unregulated search for erratic blocks also led to the removal of boundary stones. This prompted the government of Drenthe to issue a resolution on July 21, 1734, prohibiting such actions. At the same time, this resolution placed the megalithic tombs under protection. After two royal decrees in Denmark (1620) and Sweden (1630), this was the third law to protect antiquities in Europe.
In 1732, the affluent Amsterdam textile merchant Andries Schoemaker undertook a journey to Drenthe with the draughtsman Cornelis Pronk and his apprentice Abraham de Haen. This excursion resulted in the initial realistic depictions of the two megalithic tombs situated in the vicinity of Havelte (D53 and D54). Schoemaker also furnished a comprehensive account of the sites. Both draughtsmen subsequently returned to Drenthe. Two surviving drawings by Abraham de Haen of the megalithic tomb D53 from 1737 and one by Cornelis Pronk of the megalithic tomb Midlaren (D3) from 1754 provide insight into the evolution of these structures.
In 1756, Joannes van Lier was commissioned to restore the Eext megalithic tomb (D13). This site, which had been dug into the ground, had been discovered around 20 years earlier by a stone hunter and was also rediscovered by stone hunters in 1756. The vessels and axes found were sold to collectors. Two capstones were also removed. Van Lier conducted a comprehensive examination of the site and endeavored to restore the burial chamber to its original condition to the best of his ability. Just two days later, he published a newspaper article about his work. Shortly thereafter, Cornelis van Noorde created a drawing of the tomb. Henrik Cannegieter, the principal of the Latin school in Arnhem, authored a treatise on the tomb based on the newspaper article, despite having neither seen it himself nor contacted van Lier. At the suggestion of his friend Arnout Vosmaer, van Lier undertook a critical examination of this treatise in five lengthy letters. These letters ultimately resulted in the first monographic treatise on a Dutch megalithic tomb, which was published by Vosmaer in 1760.
Between 1768 and 1781, Petrus Camper created drawings of eight megalithic tombs. Among these was the Steenwijkerwold megalithic tomb (O1), which was destroyed in the 19th century.
In 1774, Theodorus van Brussel published a new edition of Ludolf Smids' Schatkamer der Nederlandse oudheden, which he augmented with extensive notes of his own. In this edition, van Brussel (who was unaware of van Lier's work) advanced the thesis that the megalithic tombs were natural formations that had formed on the seabed. He further postulated that, after the land had dried up, erosion had given them their present appearance.
In 1790, Engelbertus Matthias Engelberts published the third volume of his historical work De Aloude Staat En Geschiedenissen Der Vereenigde Nederlanden, which was aimed at a general audience. In it, he devoted himself in detail to the megalithic tombs and summarized the state of research at the time quite completely. He also added two (rather inaccurate) drawings of the Tynaarlo megalithic tomb (D6) to his text. It is also noteworthy that Engelberts observed that the flat side of the capstones in the tombs always faced downward. Consequently, he rejected the hypothesis that the structures had served as altars.
In 1790, the resolution to protect the megalithic tombs was renewed. In 1809, the Landdrost of Drenthe, Petrus Hofstede, once again prohibited the removal of stones from the graves and the digging of mounds. In 1818/19, the local authorities were obliged to closely monitor compliance with this law and to draw up annual reports.
19th century
In 1808, the Koninklijke Hollandsche Maatschappij der Wetenschappen, an academic society established by Adriaan Giles Camper, son of Petrus Camper, initiated a competition with the objective of elucidating the ethnic identity of the builders of the megalithic tombs.
In April 1809, the Emmen-Noord megalithic tomb (D41), which had previously been completely covered, was uncovered and examined. Johannes Hofstede, the brother of Petrus Hofstede, wrote a detailed report on this. His brother then obtained the exclusive right to conduct excavations in the province of Drenthe. Subsequently, he conducted further investigations at four additional megalithic tombs. However, the results of these excavations were not fully documented.
Nicolaus Westendorp made further important contributions to research at the beginning of the 19th century. In 1811, he visited the megalithic tombs in Drenthe and seven others in Germany. He wrote an extensive treatise, with which he finally won the competition announced in 1808. Westendorp described a distribution area of megalithic sites stretching from Portugal to Scandinavia. He assumed a common origin for all these sites. He adopted the observation made by van Lier that the megalithic tombs only contained stone tools. On this basis, Westendorp argued for a two-period system consisting of a Stone Age and a subsequent Metal Age. The Danish researcher Christian Jürgensen Thomsen was strongly influenced by his work in the development of his Three-age system. Westendorp compared the inventories of the megalithic tombs with the material remains of several ancient peoples and excluded most of them due to their use of metal tools. As it was implausible for him to attribute them to a previously unknown people, he argued for early Celts as the builders. He first published his theories as an essay in 1815 and then as a monograph in 1822. Westendorp's work attracted considerable attention, but also attracted criticism. For example, his hypothesis that the Celts were responsible for the megalithic tombs was called into question, given the absence of such tombs in large parts of Central and Eastern Europe, despite the presence of Celtic populations in those areas.
In the 1840s, the division of communal land was imminent. The megalithic tombs were once again in jeopardy of destruction, prompting Johan Samuel Magnin, the provincial archivist of Drenthe, to submit a petition to King William II in 1841. The petition sought to exempt prehistoric tombs from the privatization of land. However, the petition was unsuccessful. A 1842 newspaper article by Dr. Levy Ali Cohen likewise failed to effect a change in the law.
Furthermore, in the 1840s, two history books appeared that were quite popular at the time and aimed at a wide audience. These books devoted a significant amount of space to the megalithic tombs. In 1840, Johannes Pieter Arend published the first volume of his Algemeene Geschiedenis des Vaderlands. He primarily relied on the work of Engelberts and Westendorp, positing that the early Celts were the builders of the tombs. In contrast, Grozewinus Acker Stratingh advanced a novel theory in 1849, suggesting that the tombs had been constructed by unidentified ancestors of the Celts and Germanic tribes.
The most significant researcher of the 19th century was Leonhardt Johannes Friedrich Janssen (1806–1869), the curator of the Dutch antiquities collection at the Rijksmuseum van Oudheden in Leiden. His interest in megalithic tombs began in 1843 when he had several models of the Tynaarlo megalithic tomb (D6) made for various museums. In 1846, he excavated the Exloo-Zuiderveld stone cist (D31a) and the Zaalhof megalithic tomb (D44a). In 1847, he undertook a study of the Dutch megalithic tombs in situ and published a paper on them the following year. Janssen thus presented the first comprehensive descriptive overview of the surviving megalithic tombs in the Netherlands. In 1849, he conducted a further excavation of the stone cist remains in the Rijsterbos (F1). He subsequently devoted himself to questions regarding the construction methods of the tombs and the way of life of their builders. Janssen's most significant error was the dating of the sites to a period that was considerably more recent than it was. He described the pottery finds as "Germanic" and considered the youngest graves to be Roman. In 1853, he fell in love with the Hilversum worker Dirk Westbroek, who had faked several hearths that were supposed to be from the Stone Age. One of the sites yielded a worked sandstone slab from the Middle Ages or Modern era. Janssen dated this to the Roman period and interpreted it as evidence that the Stone Age in the Netherlands only ended with the Romans. Janssen's error had a profound impact on prehistoric research in Leiden for decades to come. It was not until 1932 that the hearth sites in Hilversum were exposed as a forgery.
The writer Willem Hofdijk was profoundly influenced by Janssen's work and produced several works between 1856 and 1859, in which he crafted a vivid portrayal of Dutch prehistory. Of particular interest is his dating of the megalithic tombs, which he placed in his work Ons Voorgeslacht (Unsere Vorfahren) at approximately 3000 BC. At the time, they were generally considered to be much younger, but Hofdijk, perhaps by chance, assumed a date that roughly corresponds to the findings of modern scholarship.
In 1861 and 1867, illicit excavations resulted in significant damage to the large stone tomb De Papeloze Kerk (D49). To prevent further deterioration, by around 1870, the majority of the tombs had become the property of the state or the province of Drenthe. Subsequently, several sites were restored, albeit in an unprofessional manner, at the suggestion of amateur archaeologist Lucas Oldenhuis Gratama. Gratama adopted Westendorp's erroneous assumption that the graves originally had no mounds and therefore had them removed as supposed wind drifts without documentation.
In 1871, Augustus Wollaston Franks, the curator of the British Museum, undertook a visit to Drenthe. He was dismayed by the lack of professionalism evident in the restoration of the megalithic tombs. In response, Franks suggested that William Collings Lukis (1817–1892) and Henry Dryden (1818–1899) undertake a research trip to Drenthe in 1878. Both had previously conducted investigations of megalithic sites in the United Kingdom and Brittany, and now produced highly detailed floor plans and sectional drawings of 40 megalithic tombs in the Netherlands, in addition to several watercolors of pottery finds.
Willem Pleyte, the successor of Janssen as curator at the Rijksmuseum van Oudheden, published a comprehensive list of the archaeological sites in the Netherlands known at the time from 1877 onwards. He also made extensive use of photography for the first time. The first known images of Dutch megalithic tombs were taken in 1870. In 1874, Pleyte undertook a photographic expedition through Drenthe, accompanied by the photographer Jan Goedeljee. They photographed all the megalithic tombs in the region. Pleyte subsequently used these images as models for lithographs. It is notable that Conrad Leemans, the director of the Rijksmuseum, undertook a similar photographic expedition to Drenthe in 1877. Jan Ernst Henric Hooft van Iddekinge, who had already been to Drenthe with Pleyte, prepared plans of the megalithic tombs for Leemans. However, the quality of these plans did not match the work of Lukis and Dryden.
The realization that the Dutch megalithic tombs were part of a Stone Age culture that spanned large parts of northern and central Europe gradually gained acceptance from the end of the 19th century. Nicolaus Westendorp had already noted the great similarity to the graves in northwest Germany in 1815. Augustus Wollaston Franks observed in 1872 that not only the graves but also the grave goods found were very similar to those from Germany and Denmark. In 1890, the Königsberg prehistorian Otto Tischler established the existence of various regional groups within the Funnelbeaker Culture for the first time and defined the distribution area of the Western Group more precisely. At the beginning of the 20th century, Gustaf Kossinna distinguished four regional groups based on the pottery: a northern, western, eastern, and southern group. In the 1930s, Konrad Jażdżewski presented an even more precise overview, subdividing Kossinna's eastern group into an eastern and south-eastern group.
20th and 21st century
In the early decades of the 20th century, the physician Willem Johannes de Wilde made significant contributions to the field of research. Between 1904 and 1906, he conducted a comprehensive survey of the surviving megalithic tombs in the Netherlands, meticulously documenting his observations through detailed drawings, photographs, and a comprehensive catalog of questions pertaining to the architectural characteristics of each site. Unfortunately, the majority of his original notes have been lost, leaving only fragments of his insights.
A new phase of megalithic research in the Netherlands commenced in 1912 with the excavation of two megalithic tombs near Drouwen (D19 and D20) by the Leiden archaeologist Jan Hendrik Holwerda. The following year, he conducted an investigation of the Emmen-Schimmeres megalithic tomb (D43).
Subsequently, the Groningen archaeologist Albert Egges van Giffen conducted further excavations, which significantly influenced megalithic research in the Netherlands for several decades. In 1918, he conducted a comprehensive excavation of the Havelte 1 megalithic tomb (D53), a megalithic tomb situated in the vicinity of Emmerveld (D40), the Exloo-Noord megalithic tomb (D30), and two additional megalithic tombs. Excavations were conducted in the vicinity of Bronneger (D21 and D22) and a trial excavation was carried out at the Drouwenerveld megalithic tomb (D26), the Balloo megalithic tomb (D16) and another megalithic tomb near Emmerveld (D39). Additionally, between 1918 and 1925, he conducted investigations at the remains of three previously destroyed sites: the Steenwijkerwold megalithic tomb (O1), the stone cist in the Rijsterbos (F1), and the Weerdinge megalithic tomb (D37a). Furthermore, he conducted a comprehensive survey of all surviving sites in the Netherlands between 1925 and 1927, publishing the results in two volumes of text and an atlas. In this work, he also developed the numbering system for graves that is still in use today. This system employs a capital letter for the province, followed by a number ascending from north to south. It also includes a lowercase letter for destroyed sites. In 1927, van Giffen conducted further excavations at two additional graves: the Buinen-Noord megalithic tomb (D28) and the Eexterhalte megalithic tomb (D14). In the 1940s, he undertook investigations of the remains of several destroyed sites.
During the Second World War, the stones of the Havelte 1 (D53) megalithic tomb were buried and a runway was constructed on its site. The airfield was subjected to aerial bombardment in 1944 and 1945. Following the cessation of hostilities, the site was reconstructed in its original location.
In the 1950s, van Giffen devoted himself primarily to the restoration of the graves. He made missing wall stones visible by having their holes filled with concrete. In 1952, van Giffen conducted another excavation at the Annen megalithic tomb (D9). In 1957, he collaborated with Jan Albert Bakker at the Noordlaren megalithic tomb (G1). From 1968 to 1970, he worked with Jan Albert Bakker and Willem Glasbergen at the Drouwenerveld megalithic tomb (D26).
The concept of a museum dedicated to the megalithic tombs and their builders was first proposed by van Giffen in 1959. The exhibition, developed by Diderik van der Waals and Wiek Röhling, was initially presented in a restored farmhouse in Borger from 1967. However, the house was destroyed by fire on two occasions, resulting in the museum's relocation to the former almshouse near the Borger large stone tomb (D27). In 2005, a newly constructed visitor center with open-air facilities was inaugurated on this site under the name Hunebedcentrum.
Further excavations were conducted by Jan N. Lanting between 1969 and 1993. These investigations focused on the remains of several previously destroyed sites, the majority of which had been discovered by the amateur archaeologist Jan Evert Musch. Additionally, Lanting examined the Heveskesklooster megalithic tomb, which was only discovered in 1982 and subsequently converted into a museum in 1987.
In the 1970s, Jan Albert Bakker published his dissertation on the Western Group of the Funnelbeaker Culture, which remains an authoritative overview to this day. The burial inventories of the Dutch megalithic tombs known at the time constituted a significant portion of his data basis. In 1992, he published a monograph on the architecture of the graves, and in 2010, another on the history of research.
In the 1980s, Anna L. Brindley developed a seven-stage internal chronology system for the Funnel Beaker West group, based on the extensive pottery finds from the megalithic graves.
The few bone remains known from the Dutch graves were not systematically examined for a considerable period of time. This only changed in the years between 2012 and 2015, when Liesbeth Smits and Nynke de Vries analyzed the cremations found in the megalithic tombs.
In 2017, all the megalithic tombs in the Netherlands were recorded in a three-dimensional atlas using photogrammetry. The data was obtained from a collaboration between the province of Drente and the University of Groningen by the Gratama Foundation.
Population and distribution
It is not known how many megalithic tombs originally existed in the Netherlands. Probably there were more than 100. Today, 53 tombs have been preserved. In addition, there is one that has been turned into a museum and a stone complex that is questionable as to whether it is the remains of a megalithic tomb. In addition, 23 destroyed tombs are known to have been found. Jan Albert Bakker also lists nine possible sites for which only vague information is available from older literature and whose classification as megalithic tombs is uncertain (he considers information on 19 other sites to be unreliable). Bert Huiskes was also able to identify 96 field names for the province of Drenthe that indicate possible megalithic tomb ruins.
The megalithic tombs in the Netherlands were constructed by members of the Funnelbeaker culture, a Neolithic cultural complex that originated in Denmark and subsequently spread across large parts of Europe from approximately 4100 BC to 2800 BC. The Funnelbeaker Culture was divided into several regional groups, with the northernmost group extending from central Sweden to the Czech Republic, while the southernmost group extended from the Netherlands in the west to Ukraine in the east. Megalithic burial structures were not a ubiquitous phenomenon throughout the entire distribution area, but rather were concentrated in specific regions, including Scandinavia, Denmark, northern and central Germany, northwestern Poland, and the Netherlands. The Dutch megalithic tombs, in conjunction with the sites in western Lower Saxony, are considered to be part of the western group of the Funnelbeaker Culture. The original total number of graves is difficult to ascertain with precision. Currently, approximately 20,000 sites are known to have survived or are known with certainty. Of these, over 11,600 are located in Germany, 7,000 in Denmark, and 650 in Sweden. The total number of all large stone tombs of the Funnelbeaker Culture ever erected is likely to have been at least 75,000, perhaps even up to 500,000. The Dutch tombs therefore represent a comparatively small group at the westernmost edge of the Funnelbeaker Culture.
The surviving graves are all located in the provinces of Drenthe and Groningen. The majority of them are concentrated in a narrow strip running from north-northwest to south-southeast on the Hondsrug ridge between the towns of Groningen and Emmen. Almost all of these graves are accessible via the N34 highway. Three sites are located some distance to the west of the main group near Diever and Havelte. In addition to the aforementioned sites, there is a loose scattering of several destroyed sites between the main group and the aforementioned sites. In the northern region of the province of Groningen, near the coast, the large stone tomb Heveskesklooster (G5) was discovered in 1983 beneath a terp in the municipality of Eemsdelta and subsequently relocated to the Muzeeaquarium Delfzijl.
Two megalithic tombs are known from the province of Overijssel. The Steenwijkerwold megalithic tomb (O1) was located in the province's far north, approximately 8 km from the two megalithic tombs near Havelte (D53 and D54). The Mander megalithic tomb (O2) was located east of the province, near the German border. A few kilometers to the north were the megalithic tombs near Uelsen in the county of Grafschaft Bentheim in Lower Saxony.
The Lage Vuursche stone (U1) is situated at a considerable distance from the other sites in the northern region of the province of Utrecht. If this is indeed the remains of a megalithic tomb, it would represent the southernmost and westernmost such tomb in the Netherlands and the westernmost in the distribution area of the Funnelbeaker culture.
Bakker also posits the possibility that megalithic tombs may have originated in the province of Gelderland, as similar megalithic burial sites have been identified in the neighboring region to the east, northern North Rhine-Westphalia.
Grave architecture
Grave types
The Funnelbeaker Culture is characterized by the construction of large stone tombs, which feature mounded burial chambers built from boulders. These are divided into several types based on various characteristics, with the main feature being the position of the entrance to the burial chamber. If it is located on a long side, it is referred to as a passage grave. The dolmen is the counterpart to the passage grave. It has an entrance on a narrow side or, in the case of very small structures (the Urdolmen), has no entrance at all. Further classification features include the number of passage stones, the shape of the mound, and the presence or absence of a stone enclosure.
Of the 54 surviving enclosures in the Netherlands, 52 can be classified with certainty or a high degree of probability as passage graves. Another is too badly destroyed for a reliable classification. Albert Egges van Giffen once again distinguished four subtypes:
The term "ganggraf" (passage grave) was employed by Van Giffen to describe graves with a stone enclosure and a covered passage in front of the entrance.
The "portaalgraf" (portal grave) is defined by van Giffen as a type of grave whose entrance is preceded by a pair of passage stones without a capstone.
The "trapgraf" (staircase grave) is a type of enclosure sunk into the ground whose burial chambers are accessible by a stone staircase rather than a horizontal passage. The only example of this type in the Netherlands is the Eext megalithic tomb (D13). Tombs with this type of access construction are also rare in the rest of the Funnelbeaker Culture distribution area. Only four examples from Lower Saxony (the Deinste 1 megalithic tomb, the Krelingen megalithic tomb, the Sieben Steinhäuser C megalithic tomb, and the destroyed Meckelstedt 2 megalithic tomb) are known to be comparable.
The term "langgraf" (long grave) is used to describe a complex consisting of a long barrow bed enclosing multiple burial chambers. The only example of this type in the Netherlands is the Emmen-Schimmeres megalithic tomb (D43). Additionally, analogous sites of this type have been identified in Lower Saxony, including the Daudieck megalithic bed A, the Kleinenkneten II megalithic tomb, and the Tannenhausen megalithic tomb.
In more recent literature (e.g., Bakker), the terms van Giffens are no longer used, and all these sites are instead referred to simply as passage graves. In Lower Saxony, the term Emsland chamber was coined for a sub-type of passage grave typical of the western group of the Funnelbeaker Culture. A large proportion of the Dutch passage graves also correspond to this type. The Emsland chamber is distinguished by a relatively lengthy, predominantly east–west oriented burial chamber with an entrance on the southern long side, which is enclosed at a short distance by a stone enclosure.
The Heveskesklooster (G5) is a notable exception among the Dutch sites. It is the only known dolmen (or more precisely, a great dolmen) in the country. It consists of three pairs of wall stones on the long sides, a capstone on the northern narrow side, and three capstones. The entrance is located on the open southern narrow side.
Smaller burial complexes, which are typically constructed by deepening the chambers into the ground and using small stone slabs, are referred to as stone cists. Examples of these structures from the Funnelbeaker period have also been identified in the Netherlands. However, these structures are not typically classified as large stone tombs.
Mound fill and enclosure
All the graves originally had a mound fill. This was round in the smaller sites and oval in the larger ones. Only the Emmen-Schimmeres megalithic tomb (D43) has a different shape. Here, the two burial chambers lie in a slightly trapezoidal long bed with rounded narrow sides and a stone enclosure. An enclosure was also found in eight or nine other enclosures. These enclosures are invariably larger, with a chamber length of at least 8 m.
Burial chamber
Orientation
In the majority of passage tombs, the burial chambers are oriented approximately east–west, with the entrance facing south. There is considerable variation in orientation, ranging from northeast–southwest to southeast–northwest. However, the ends of almost all chambers lie within the extreme points of the rising and setting of the sun and moon. Six chambers deviate from this and have an orientation between south-southeast-north-northwest and south-southwest-north-northeast.
Chamber size and number of stones
The dimensions of the chambers exhibit considerable variability. The shortest chamber, with an inner length of 2.5 m, is observed in the large dolmen of Heveskesklooster (G5). The smallest passage grave was the destroyed megalithic tomb Glimmen-Zuid (G3), with an inner chamber length of 2.7 m and an outer length of 3.2 m. The Borger megalithic tomb (D27) has the largest burial chamber. It has an inner length of 20 m, an outer length of 22.6 m, and a width of 4.1 m.
The number of pairs of wall stones on the long sides is between two and ten, the number of capstones between two and nine.
Chamber shape
The ground plan of the burial chambers of the passage tombs is typically slightly trapezoidal, with a slight widening on the left side as seen from the entrance. This widening is observed in 36 chambers, with a corresponding shape identified in 29 of them. However, the difference in width varies considerably. In the majority of the tombs, the width difference is between 7 cm and 50 cm. However, three chambers exhibit a significantly greater difference in width, with values of 87 cm, 88 cm, and 106 cm, respectively. Of the remaining seven chambers measured, five are wider at the right end than at the left. Here, the difference in width is only between 9 cm and 21 cm. In two chambers, both ends are exactly the same width.
The entrance
In the majority of cases, the entrance to the chambers of the passage tombs is situated in the middle of the southern or eastern long side. In the tombs with three to five pairs of wall stones, the entrances are typically offset to the right. However, there are also instances where they are precisely in the middle and, on two occasions, they are offset to the left. Of the seven graves with seven pairs of wall stones, four have an entrance that is more or less precisely in the middle, one is offset to the left, and one is offset to the right. In the graves with nine or ten pairs of wall stones, the entrances are also in the middle or slightly offset to the right. Only the Emmen-Noord megalithic tomb (D41) deviates conspicuously from this construction method. The structure comprises four pairs of wall stones and has an entrance located at the western end of the southern long side between the first and second wall stones.
The entrance to the chamber is either a simple opening between two wall stones or preceded by a passageway, which typically has one or two pairs of wall stones. Only one grave has evidence of a passage with three pairs of wall stones. Longer corridors, such as those typical of the large stone tombs of the Funnelbeaker North group, do not occur in the Netherlands.
At the large stone tomb Eext (D13), a staircase leads to the entrance instead of a passageway. According to van Lier's investigation in 1756, this staircase consisted of four steps, each made of one or two flat stone slabs and bordered by two walls of rolled stones. At the bottom of the stairs was a threshold stone directly in the entrance to the chamber. In 1927, Albert Egges van Giffen discovered that the staircase construction had been destroyed.
The chamber floor
The floor of the burial chambers is typically composed of multiple layers of different stones. The uppermost layer typically consists of burnt granite grus. This is followed by sandstone slabs or rubble of round or flat shape. In some graves, there appears to have been another layer of stones underneath. The floors are typically not level, but exhibit a slight decline towards the center. The differences in height range from 25 to 50 cm.
In the Funnelbeaker North Group, the burial chambers are frequently subdivided into multiple sections by stone slabs set vertically into the floor. This is less prevalent in the Western group and is only known from one grave in the Netherlands. In the northern megalithic tomb at Drouwen (D19), Jan Hendrik Holwerda discovered a row of three 70 cm long and 30 cm high slabs at the north-western end of the chamber, which delineated a small space 2 m wide and 1 m long.
Dry stone
The gaps between the wall stones of the chambers were originally filled from the outside with dry stone made of horizontally laid hewn stone slabs. Only remnants of this remain today. The maximum preserved height of the masonry was 1.4 m in the large stone tomb Bronneger 1 (D21). In some of the very long chambers, larger gaps were not completely filled with dry masonry. Instead, smaller upright erratic blocks were also inserted, which did not carry a capstone.
Funerals
In contrast to many other areas with megalithic tombs, very little organic material has survived in the Dutch megalithic tombs. This also applies to the bones of the people buried here. Jan Hendrik Holwerda, during his investigation of the two sites in Drouwen, was able to identify poorly preserved human skeletal remains in grave D19. These were mainly teeth and remains of jaw bones.
Remains of cremated remains were found in 26 graves. In some cases only a few grams were preserved, but more than 1 kg was recovered from each of the two megalithic tombs at Havelte (D53 and D54) and the destroyed megalithic tomb Glimmen 1 (G2). The total weight of cremated remains recovered from all Dutch megalithic tombs is just under 8 kg. In most cases the bone fragments could only be assigned to single individuals, but in two graves five individuals could be distinguished. A total of 48 individuals were identified.
Bones from several graves were radiocarbon-dated, confirming that they were from funnel beaker burials.
Only limited statements can be made about the sex and age at death of the burials, as neither could be determined accurately or at all for the majority of individuals. According to the analysis of Nynke de Vries, there is probably a slight surplus of males among the dead. Most of the individuals had died as adults. The burials of children and adolescents make up only a small proportion.
Enclosures
Ceramics
Ceramic vessels make up by far the largest part of the Funnelbeaker Period grave goods. The largest number comes from the megalithic grave Havelte 1 (D53). The sherds found here could be reconstructed into 649 vessels. The destroyed megalithic grave Glimmen 1 (G2) contained about 360 vessels and the megalithic grave Drouwenerveld (D26) 157.
The range of pottery forms is quite diverse. The funnel cup, a bulbous vessel with a long funnel-shaped neck, gave its name to the culture of the Great Stone Cavemen. Similar vessels with eyelets on the neck and shoulder are known as eyelet or showpiece cups. Collar bottles are small, bulbous bottles with a widening below the mouth. Amphora are bulbous vessels with a short cylindrical rim. The eyelet or dolmen bottle has a funnel-shaped neck, which can be very long in some specimens. There are one or two pairs of eyelets at the neck-shoulder junction. A similar vessel shape is the eyelet beaker, in which the eyelets are located near the base. Jugs are tripartite with a funnel-shaped rim and one or two handles. Shoulder cups have the same structure as jugs, but are wider than they are tall. Steep-walled cups have a straight wall that widens slightly at the top. There are also bowls with straight or convex walls and dishes. Fruit or foot bowls consist of a convex or funnel-shaped neck and a similar base. Both may be joined by one or two handles. Neck-grooved vessels are two-piece flat bowls with a conical rim. They do not appear until the late phase of funnel beaker culture. Tulle cups consist of a bowl and an attached hollow spout. Spoons have a solid handle instead of a spout. The two forms are not always easy to distinguish (especially when broken). There are also flat ceramic plates known as baking plates. The only shapes that have been found are a spindle-like object and a model of a stool or throne.
Stone tools
Other common grave goods are flint tools. These include hatchets, crossed arrowheads, scrapers, blades, and flakes. Crossed arrowheads are the largest group in terms of numbers. Hatchets, axes and stone hammers are rare. A club head is documented only once.
Jewelry
Amber beads are the most prevalent type of jewelry discovered. Occasionally, beads crafted from jet and quartz and pendants crafted from perforated fossils are also unearthed.
Metal
The discovery of metal objects is a rare occurrence. In the Drouwen 1 megalithic tomb (D19), strips were found, while spirals were discovered in the Buinen 1 megalithic tomb (D28). Additionally, a sheet of copper or arsenical bronze was uncovered in the Wapse megalithic tomb (D52a). These are the oldest metal finds in the Netherlands.
Animal bones
The remains of burnt animal bones were discovered in 20 megalithic tombs. These included bones from domestic pigs, cattle, sheep/goats, horses, canids, bears, red deer, and possibly roe deer. It is likely that these bones were used as tools, although at least one bone seems to have been used as a food offering. Given that only claws were recovered from the bear, it is possible that the remains represent the cremated remains of a bearskin with which a person may have been wrapped.
Laying down in front of the graves
The discovery of Funnelbeaker pottery vessels and stone tools in front of the entrances to several megalithic tombs, including the Drouwenerveld megalithic tomb (D26) and the Eexterhalte megalithic tomb (D14), indicates that these items were deposited in these locations at a specific point in time. The removal of the mounds of the two megalithic tombs near Midlaren (D3 and D4) around 1870 may have uncovered corresponding ritual pits, though these were not recognized as such. The pottery is of similar quality and style to that found in the burial chambers and dates to the same period. However, storage vessels and baking plates as well as flint scrapers are absent from the deposits.
Dating of the Funnelbeaker Period phases of use
The range of forms and decoration of the ceramic vessels allows for the distinction of several typological stages within the Western Group of Funnelbeakers. These stages also indicate different phases of use of the megalithic tombs. The subject was previously studied by Heinz Knöll and Jan Albert Bakker, who conducted important earlier work in this field. The typological system that is still relevant today was developed by Anna L. Brindley in the 1980s. By comparing a substantial quantity of carbon-14 dating, Moritz Mennenga was able to present the most precise absolute chronological dating of these stages to date in 2017.
Level 1 pottery was discovered in five graves, representing the earliest archaeological material recovered. These graves were small enclosures with two to five pairs of wall stones, chamber lengths between 2.7 and 6.1 meters, round or oval mounds without enclosures, and an entrance with a pair of passage stones or without passage stones. Seven or eight additional graves were constructed during Stage 2. Some of these graves also contained small chambers, while others had larger chambers with up to seven pairs of wall stones and lengths of up to 12.4 m. The Drouwenerveld megalithic tomb (D26) and the Emmen-Schimmeres megalithic tomb (D43), which has two burial chambers, are the first graves to have a stone enclosure. All other graves of this level still have a mound without an enclosure. The peak of the construction of the megalithic tombs falls on level 3. In 13 tombs, the corresponding pottery represents the oldest found material. Both small and large enclosures continued to be erected. The chambers now had up to ten pairs of wall stones and were up to 17 m long. Mounds were constructed with or without enclosures, and the entrances had zero to two pairs of wall stones. No new megalithic tombs appear to have been erected after level 3. However, large quantities of pottery provide evidence for the continued use of almost all sites up to level 5, after which many graves were abandoned. Pottery from levels 6 and 7 was only found in a few sites. Furthermore, there is evidence of an interruption in the use of some graves. For instance, the destroyed large stone tomb Glimmen 1 (G2) was utilized during levels 3–5, abandoned in level 6, and then reused in level 7.
Subsequent use of the graves
Late Neolithic and Early Bronze Age
Funerals
In the majority of Dutch megalithic graves, vessels and stone tools from the Single Grave Culture and the Bell Beaker Culture (both Late Neolithic) and the Early Bronze Age coiled cord pottery were discovered in addition to the Funnel Beaker Period grave goods. These findings are typically regarded as grave goods from secondary burials. What is noteworthy is that in addition to the typical burial pottery of this period, large amphorae and storage vessels were also discovered, which are otherwise only known from settlements. However, these are almost completely absent from individual graves. Therefore, it can be inferred that the megalithic tombs were utilized for special burials.
Shell stones
In prehistoric times, small circular bowls were attached to several megalithic tombs in the Netherlands. During an investigation in 2018, Mette van de Merwe identified seven sites in which such carvings were present. In five cases, the small bowls are located on capstones, in one case on a wall stone, and in another case on an enclosure stone. The exact purpose of these bowls is unknown. Furthermore, there are no concrete indications as to their date in the Dutch graves. Therefore, a comparison with other regions is necessary. In his investigations of the megalithic graves in Mecklenburg-Western Pomerania, Ewald Schuldt found no evidence that the bowls there were made by members of the Funnel Beaker Culture. They appear to be rather younger, as in several cases they were discovered in places that were probably only accessible again after a certain period of decay of the burial chambers. In contrast, several large stone graves with small bowls are known from Schleswig-Holstein, which were covered over again in the Late Neolithic and Bronze Age and used for new burials. For Jan Albert Bakker, this evidence suggests that the bowls can probably be dated to the Late Neolithic and Early Bronze Age.
Middle Bronze Age to Middle Ages
Following the Early Bronze Age, the megalithic tombs appear to have been largely unused, as finds from more recent periods are exceedingly rare. A notched Bronze Age urn was discovered in the destroyed Spier megalithic tomb (D54a). A Middle Bronze Age razor was discovered in the Westenesch-Noord megalithic tomb (D42), while a vessel from the Iron Age Harpstedt group was unearthed in the Drouwenerveld megalithic tomb (D26). In 1750, a Roman silver coin is said to have been found in the Eexterhalte megalithic tomb (D14). In the late 18th century, a boat model was discovered in the Loon megalithic tomb (D15), which is believed to date to the Early Middle Ages. Two similar examples are of unknown origin. It is probable that some early to high medieval vessels were also deposited in megalithic tombs.
References
External links
The Megalithic Portal: Netherlands
Hunebedden in Nederland (Dutch)
De hunebedden in Drenthe en Groningen (Dutch)
Het Hunebed Nieuwscafé (Dutch)
Hunebeddenwijzer (Dutch)
JohnKuipers.ca: A Hunebed Map of Drenthe
cruptorix.nl: De hunebedden in Nederland (Dutch)
Website des „Hunebedcentrum“ in Borger (Dutch)
De Hunebedden in Nederland – 3D-Atlas (Dutch)
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Jan N. Lanting: Het na-onderzoek van het vernielde hunebed D31a bij Exlo (Dr.). In: Paleo-Aktueel. Volume 5, 1994, S. 39–42 (online).
Jan N. Lanting: Het zogenaamde hunebed van Rijs (Fr.). In: Paleo-Aktueel. Volume 8, 1997, p. 47–50 (online).
Jan N. Lanting: Wat is er werkelijk bekend over Hunebed D12, respektievelijk de schreden en kompasrichtingen bij Van Lier? In: Jan N. Lanting: Kritische nabeschouwingen. Barkhuis, Groningen 2015, , p. 65–88.
Jan N. Lanting, Anna L. Brindley: The destroyed hunebed O2 and the adjacent TRB flat cemetery at Mander (Gem. Tubbergen, province Overijssel). In: Palaeohistoria. Volume 45/46, 2003/2004 (2004), p. 59–94 (online).
W. Meeüsen: Het verdwenen hunebed D54a bij Spier, gem. Beilen. Dissertation, Groningen 1983.
Pieter J. R. Modderman: Beaker Pottery from Hunebed D19 near Drouwen, Prov. Drenthe. In: Analecta Praehistorica Leidensia. Volume 4, 1971, p. 47–51 (PDF; 2,24 MB).
J. Molema: Het verdwenen hunebed D43a op de Emmer Es te Emmen. Dissertation, Groningen 1987.
Jan Willem Okken: De verhinderde verkoop van hunebedden te Rolde, 1847–1848. In: Nieuwe Drentse Volksalmanak. Volume 106, 1989, p. 74–86.
Daan Raemaekers, Sander Jansen: Een papieren opgraving van hunebed D12 Eexteres. Van ganggraf naar dolmen. In: Paleo-aktueel. Volume 24, 2013, p. 43–50 (online).
Wijnand van der Sanden: Reuzenstenen op de es. De Hunebedden van Rolde. Waanders, Zwolle 2007, .
Wijnand van der Sanden: Een hunebed in een park – Een bijdrage tot de biografie van het grote hunebed van Borger. In: Waardeel. Volume 31 (1), 2011, p. 1–5 (online).
C. W. Staal-Lugten: Die verzierte TRB-Keramik des Hünenbettes D19 in Drouwen, Prov. Drenthe. In: Analecta Praehistorica Leidensia. Volume 9, 1976, p. 19–37 (online).
Ernst Taayke: Drie vernielde hunebedden in de gemeente Odoorn. In: Nieuwe Drentsche Volksalmanak. Volume 102, 1985, p. 125–144.
Adrie Ufkes: De inventarisatie van Hunebed O2 van Mander. Dissertation, Groningen 1992.
Adrie Ufkes: Het hunebed O2 bij Mander (OV.). In: Paleo-aktueel. Volume 4, 1992, p. 31–32 (online).
Adrie Ufkes: Trechterbekeraardewerk uit het hunebed D52 te Diever, gemeente Westerveld (Dr.). Een beschrijving van een particuliere collectie (= ARC-Rapporten. Volume 2007–20). ARC, Groningen 2007 (online).
Special studies
Wout Arentzen: W.J. de Wilde (1860–1936). Een vergeten onderzoeker van de Nederlandse hunebedden. Sidestone Press, Leiden 2010, (online).
Wout Arentzen: Nicolaus Westendorp (1773 – 1836). Een dominee op zoek naar 't begin van 't Vaderlands Verleden. Sidestone Press, Leiden 2022, (online).
Jan Albert Bakker: July 1878: Lukis and Dryden in Drente. In: The Antiquaries Journal. Volume 54/1, 1979, p. 9–18.
Jan Albert Bakker: Protection, acquisition, restoration and maintenance of the Dutch hunebeds since 1734. An active and often exemplary policy in Drenthe (I). In: Berichten van de Rijksdienst voor het Oudheidkundig Bodemonderzoek. Volume 29, 1979, p. 143–183 (online).
Jan Albert Bakker: De opgraving in het Grote Hunebed te Borger door Titia Brongersma op 11 juni 1685. In: Nieuwe Drentse Volksalmanak. Volume 101, 1984, p. 103–116.
Jan Albert Bakker: Petrus en Adriaan Camper en de hunebedden. In: J. Schuller tot Peursum-Meijer, Willem Roelf Henderikus Koops (Ed.): Petrus Camper (1722 - 1789). Onderzoeker van nature. Universiteitsmuseum, Groningen 1989, , p. 189–198.
Jan Albert Bakker: Prehistory Visualised: Hunebedden on Dutch School Pictures as a Reflection of Contemporary Research and Society. In: Berichten van de Rijksdienst voor het Oudheidkundig Bodemonderzoek. Volume 40, 1992, p. 29–71 (online).
Jan Albert Bakker: Chronicle of megalith research in the Netherlands, 1547–1900: from giants and a Devil's Cunt to accurate recording. In: Magdalena Midgley (Ed.): Antiquarians at the Megaliths (= BAR International series. Band 1956). Archaeopress, Oxford 2009, , p. 7–22.
Jan Albert Bakker, Willy Groenman-van Waateringe: Megaliths, soils and vegetation on the Drenthe Plateau. In: Willy Groenman-van Waateringe, M. Robinson (Ed.): Man-made Soils (= Symposia of the Association for Environmental Archaeology. Volume 6 = BAR International Series. Volume 410). B.A.R., Oxford 1988, , p. 143–181.
Jaap Beuker: Von Schiffsbohrwurm zum Hunebed Highway. Schutz und touristische Erschließung der niederländischen Megalithgräber. In: Nachrichten des Marschenrates zur Förderung der Forschung im Küstengebiet der Nordsee. Volume 57, 2020, p. 50–56 (online).
Anna L. Brindley: The typochronology of TRB West Group pottery. In: Palaeohistoria. Volume 28, 1986, p. 93–132 (online).
Anna L. Brindley: The use of pottery in dutch hunebedden. In: Alex Gibson (Ed.): Prehistoric Pottery: People pattern and purpose (= British Archaeological Reports. Volume 1156). Archaeopress, Oxford 2003, , p. 43–51 (online).
A. César Gonzalez-Garcia, Lourdes Costa-Ferrer: Orientations of the Dutch Hunebedden. In: Journal for the History of Astronomy. Volume 34/2, No. 115, 2003, p. 219–226 (online).
Rainer Kossian: Nichtmegalithische Grabanlagen der Trichterbecherkultur in Deutschland und in den Niederlanden (= Veröffentlichungen des Landesamtes für Denkmalpflege und Archäologie Sachsen-Anhalt – Landesmuseum für Vorgeschichte. Volume 58). 2 volumes. State Office for Monument Preservation and Archaeology Saxony-Anhalt - State Museum of Prehistory, Halle (Saale) 2005, .
Mette van de Merwe: Een zoektocht naar cup marks op de Nederlandse hunebedden. Saxion Hogeschool, Deventer 2019 (PDF; 20,4 MB).
Jan Willem Okken: Mr. L. Oldenhuis Gratama en het behoud van de hunebedden. In: Nieuwe Drentse Volksalmanak. Volume 107, 1990, p. 66–95.
Wijnand van der Sanden: In het spoor van Lukis en Dryden. Twee Engelse oudheidkundigen tekenen Drentse hunebedden in 1878. Matrijs, Utrecht 2015, .
Roel Sanders: De oriëntatie van hunebedden Zon, maan of sterren? In: Waardeel. Volume 33 (3), 2013, p. 14–16 (online).
Elisabeth Schlicht: Kupferschmuck aus Megalithgräbern Nordwestdeutschlands. In: Nachrichten aus Niedersachsens Urgeschichte. Volume 42, 1973, p. 13–52 (online).
Nynke de Vries: Excavating the Elite? Social stratification based on cremated remains in the Dutch hunebedden. Masterarbeit, Groningen 2015 (online).
Movies
Alun Harvey: Dutch Dolmens. Hunebedcentrum, Borger 2021. In: YouTube. April 23, 2021, retrieved on May 20, 2021.
Dutch Dolmens, Skeletal Remains of Burial Mounds. History and Excavation. Drenthe, Netherlands. History With Kayleigh, 2020. In: YouTube. June 23, 2020, retrieved on October 6, 2021.
Sacral architecture
Funnelbeaker culture
Prehistoric Netherlands | Megaliths in the Netherlands | [
"Engineering"
] | 16,013 | [
"Sacral architecture",
"Architecture"
] |
76,719,625 | https://en.wikipedia.org/wiki/Covering%20%28construction%29 | In construction, covering is the exterior layer of a building's roof. The covering ensures waterproofing by directing and collecting rainwater. It also provides mechanical protection against various external elements such as dust and intrusions. Additionally, it must withstand static mechanical pressures from snow and dynamic forces from strong winds (pressure and uplift).
Considered as the fifth facade of the building, it also contributes to the aesthetic appeal and character of the structure.
Functions
The roof covering is the exterior part of the roof and does not contribute to the building's stability. It is designed to endure all weather conditions such as rain, snow, hail, and wind, as well as external environmental factors like marine environments and the weight of maintenance personnel. From the ridge to the drainage system, the roof covering directs rainwater by gravity and contributes to waterproofing.
As a visible element from the outside, the roof covering contributes to the heritage and architectural value of the building.
Composition
A roof covering is composed of various elements including:
Roof support (beams, boards, rafters, battens, etc.)
Roof underlayment (waterproof membrane, thermal insulation, etc.)
Ventilation elements for the underlayment (moisture and vapor evacuation)
Roof covering, visible exterior coating (tiles, slates, shingles, etc.)
Elements ensuring rainproofing and proper drainage of the roof (ridge caps, flashing, edge waterproofing elements, etc.)
A water collection system (eaves) and rainwater drainage (gutters)
Roof windows or skylights.
Roof underlayment
The roof underlayment is used to prevent accidental penetration of rainwater or powdery snow, to prevent convective exchanges with thermal insulation, and to control the migration of water vapor. It is an element of the building's thermal performance.
The roof underlayment is placed between the frame and the roof support. Two types of underlayments are distinguished: rigid underlayments, usually made of wood such as panels and boards, and flexible underlayments made of bituminous material or synthetic material, reinforced or not. Flexible underlayments can have High Vapor Permeability (HVP), which affects water vapor migration and also impacts the installation of thermal insulation.
Roof support
The roof support, attached to the frame, serves as a fixing support for the roof elements. It is usually a lathing or boarding. Lathing is a network of horizontal wooden slats, square or rectangular in section, called battens. In the presence of a flexible underlayment, counter-battens are placed under the lathing. Boarding consists of a decking of boards, which are wooden planks. Alternative industrial solutions, such as fiber cement, exist. Some roofing elements, such as steel roofing or slate, do not require roof support.
Ventilation
Roof ventilation ensures the proper preservation of the timber in the attic and regulates the humidity level by preventing condensation. Two ventilation systems are distinguished:
The ridge vent system consists of punctual openings (generally with a 1 dm2 section) arranged to facilitate air circulation. These are placed at the bottom of the windward slopes (in areas of positive pressure) and at the top of the leeward slopes (in areas of negative pressure).
The linear system allows air to pass at the base of the roof (at the eaves), along the slopes, and at the ridge. It is mandatory in mountainous areas and has the advantage, especially with underlayment, of homogenizing ventilation.
Roofing elements
Technologically, two types of installations are distinguished: roofing with small elements and roofing with large elements. Roofing with small elements includes slates, tiles, and shingles. The principle of waterproofing guiding their installation is overlapping. Roofing with large elements includes sheet metals, profiled metal or plastic trays, and corrugated fiber-cement sheets. Their waterproofing principles may involve overlapping, stapling, the application of elastomer seals, etc.
Some traditional roofing materials, such as thatch or green roofs, do not fit into these two categories.
Roofing with small elements
Tiles
Tiles are rigid plates manufactured by molding or pressing. They come in various shapes depending on regional specifics or their location on the roof: flat, corrugated, curved, and saddleback. The material is often terracotta, but it can also be concrete, glass, or metal (zinc, steel). They can be installed on lathing or boarding, or even on specific tile supports.
Terracotta tiles represent the primary roofing material in France and many other countries. These elements are made of clay fired at high temperatures. The obtained colors depend on the clay used and the surface treatment applied during finishing.
Several types of tiles, each with their relative installation specifics based on their shape, exist, such as the canal tile, flat tile (with regional variations like the glazed tile from Burgundy or the Alsatian tile), Flemish tile, or interlocking tile.
Slates
Natural slates are elements made of very fine schist stone. They are manufactured from slate schist, cut and sawn to the desired dimension. Slate shapes include rectangular, rounded, pointed, or diamond-shaped. A slate is waterproof, non-porous, frost-resistant, and resistant to the most aggressive atmospheric agents.
Fiber-cement slates are prefabricated elements made of cement to resemble natural slates. They can be pigmented throughout or surface-colored. The early fiber-cement slates contained asbestos.
The geographical distribution of slate roofs is linked to the shale richness of the subsoil: Anjou, Brittany, Ardennes, certain parts of the Pyrenees, and the Massif Central in France. In Europe, natural slates usually come from Spain.
Slates are installed with hooks or nails. Two types of supports can be used: battens or boarding (also known as continuous support).
Bituminous shingles
Bituminous shingles, also called "shingles," consist of a fiberglass or cellulose felt reinforcement and a mixture of bitumen and mineral granules. Various shapes are available: rounded, rectangular, and scale-like. These products are easily installed on low-slope roofs and lightweight structures due to their low weight. The most common installation method is nailing the elements to a continuous support, made of particle boards or continuous boarding.
Wooden shingles
Roofs made of wooden shingles, also called wooden scales or shingles, are made of larch, chestnut, or red cedar. They represent an ancient technique still found in Franche-Comté, the Vosges, or Savoie. Small wooden elements are nailed in place, similar to slates. Here again, some artisans perpetuate and revive this technique, mainly found in mountainous areas but also in plains. The virtually decay-resistant wood gradually changes color over time to blend into silver-gray hues.
Lauzes
They are mainly found in the Massif Central, Burgundy, Champagne, and Lorraine. They are also traditional in mountainous regions. Despite being prohibitively expensive, they are often replaced by more modern materials. However, there is still a resurgence, and the expertise of roofers persists. Unfortunately, the extraction of these products has ceased in many regions. A revival is taking place through local productions, imports from Aosta Valley in Italy for Alpine roofs, and the appearance in recent years of industrial products imitating lauzes. All these products, regardless of their size and origin, require reinforced frameworks and are generally installed using the double roofing technique.
Roofing with large elements
Two types of materials are distinguished:
Self-supporting steel trays (or aluminum, but less commonly used) installed directly on the framework.
Sheet metals (zinc, copper), supported by continuous backing.
Sheet metal roofs have excellent durability over time and develop a patina that enhances their appearance. Copper turns black and then patinates or oxidizes into a green hue. Zinc, on the other hand, acquires a highly appreciated platinum ash color. Both zinc and copper are easy to shape, bend, and weld, making them suitable for even the most complex installations.
Installation of sheet metals
Support:
The support consists of continuous boarding (with a spacing of 5 mm between boards) or continuous backing (plywood or chipboard) covered with a film with studs to allow air circulation between the support and the metal elements.
Arrangement:
Custom-shaped elements are arranged parallel to the line of greatest slope and connected by stapling (butt joint system) or reliefs + cover joints (batten system). Junctions not parallel to the line of greatest slope are made differently depending on the slope of the slope. Junctions must ensure waterproofing, free expansion, and fixing of the elements. The width of the sheets is determined by the exposure to wind.
Steel trays
Also known as self-supporting covers (with no continuous support), they were originally reserved for industrial buildings but have found some applications in housing, especially in mountainous areas, due to their economic, frost-resistant, and reliable qualities. These products, made of galvanized, lacquered, and ribbed sheets, are also available in a wide range of colors. These covers are particularly used in countries prone to strong winds and tropical cyclones, such as the Caribbean and the Indian Ocean (Reunion, Mauritius, etc.). The significant ribbing of these elements eliminates the need for purlins, and fixing is done by screw and sealing washer at the upper part of the joint between two plates. Steel trays are commonly sold in lengths of up to 12 meters, adaptable upon request, and in widths ranging from 0.6 to 1.1 meters. The span of these products depends on the depth of the ribs, the thickness of the sheet, as well as the climatic constraints to be taken into account, ranging from 2 meters to 7 meters and more. To solve condensation problems due to differences in indoor and outdoor temperatures, as well as acoustic issues, double-skinned steel trays with internal insulation are offered.
Panels for roofing
The most well-known forms are corrugated sheets made of galvanized steel, fiberglass, or bituminous synthetic material. Very lightweight and inexpensive, these sheets are very easy to apply by simple screwing (with screws) or nailing onto rafters. Other, more recent sheets replicate one or several rows of tiles, with colors that resemble, depending on the regions, either tiles or slate. Quick to install, these sheets have the advantage of being very economical. These sheets are available in electro-galvanized steel, galvanized with painted coating, and also synthetic material, generally in more or less standard dimensions of 1 meter in width by 2 meters in length. These different molded sheets also exist in translucent materials of the same dimensions and can be interposed on an opaque roof without any problem.
Other types of roofing
Thatch
Still very present fifty years ago on rural buildings in several French regions, notably in Normandy and the Camargue, thatch had almost disappeared due to a lack of specialists. There are now a few dozen practitioners across the country who install this type of roofing, which is designed to last 30 to 50 years when properly implemented. Dried reeds are used, tightly bundled to prevent water from seeping through.
Green roofs
Existing for several thousand years and used by a few pioneers in the United States, these roofs, intended for low-slope roofs, have made a comeback in northern Europe since the 1970s and are beginning to be established in Latin countries. Particularly suitable for absorbing thermal shocks, they are favored for their aesthetics and ecological impacts: attenuation of urban heat peaks, buffer zones during rainfall, improved humidity in the home, and CO2 absorption. Their implementation has a low additional cost compared to more traditional roofs, and they offer the advantage of better waterproofing.
Transparent glass roofing
Built to bring in light and warmth from the sun, these coverings, more commonly known as glass roofs, became very popular from the 15th century during the Italian Renaissance and then in Europe, to glaze the arcades of large royal estates' Orangeries and the pleasure greenhouses in the 19th century. It was also during this period that this type of roofing was used to protect railway station halls, large hotels, exhibition halls and museums, department stores, shopping arcade passages, and some grand palaces (Reichstag building, Grand Palais in Paris, etc.); all on superb metal architecture, all classified as Historical Monuments.
The material used initially was single-pane glass, known to the Romans but little used in civil architecture until the 15th century. The evolution of techniques towards "sandwich" glass composed of two glass sheets glued to a synthetic film improved mechanical resistance, safety, and allowed for larger glazed surfaces. The use of glass with a central metal framework (factory roof sheds), organic glass, resin as for polycarbonate sheets, widely used for veranda roofing due to their lightness, insulation power, and impact resistance. Modern techniques and the use of synthetic glass allow for the creation of tinted, opaque, curved, custom-sized glass, etc. Ventilation of premises can be ensured by installing translucent panels on roofs (Vasistas).
Rainwater receivers
Rainwater receivers come in two types: gutters (commercial profiles) and custom-made gutters manufactured according to an existing support.
They are characterized by their evacuation potential (flow rate in liters per second), which will depend on:
Their slope (minimum 0.005 m/m);
Their shape;
Their cross-section in cm² (for low-slope gutters with variable development);
The projected area of the slopes they serve.
The maximum allowable flow rate is 3 l/min/m² (projected surface area). They are connected to the sewage network by cylindrical downpipes for rainwater (E.P.) of various diameters or square/rectangular with different cross-sections (cm²). It is considered that 1 cm² of section evacuates 1 m² of ground surface in the case of a cylindrical connection to the receiver. In the case of a tapered connection (funnel), this value is reduced to 0.7 cm²/m². The capacity of structures collecting rainwater will be calculated based on the ground projection in m² of the slopes considered.
These structures are commonly referred to as "galvanizing" or "roofing" and fall under the responsibility of the roofer, plumber, or plumber-roofer.
Construction technique
Two construction lines, however, are common to all installation techniques:
The level line;
The line of greatest slope (the path followed by water by gravity on a slope).
They are perpendicular. The elements of a roof will always be arranged according to these lines, which will also serve as the basis for all implementation drawings.
Edges
Edges are the lines that determine the geometric limits of a slope. They can be integrated into the slope (chimney passage, roof window, ventilation), at the junction of two slopes, or at the boundary of a building. They are classified and treated differently depending on their orientation relative to the line of greatest slope.
Edges that water follows or straight edges parallel to the line of greatest slope.
Edges that water escapes (ridge, hips) forming an acute angle with the level line.
Edges that receive water (gutters, valleys, beveled edges) forming an obtuse angle with the level line.
Inherent problems with waterproofing, durability, and resistance of roofing
One of the major problems to be solved in establishing installation rules is capillarity (water rising) between elements. It is decisive in the choice of joint type or the value of overlap. Phenomena due to wind action, overpressure, and depression, static loads (snow, ice) influence supports and fixings. Condensation, electrochemical incompatibility between metals or between metals and materials (specific wood species or concrete) compromise the durability of structures.
Roofer
One of the major challenges in the roofing profession lies in how to carry out these works depending on whether they are located at the junction of slopes or not.
The work of the roofer therefore consists of:
Choosing a material
Choosing an installation technique
Marking the location of each element
Shaping the materials
Installing them while respecting waterproofing, fixing, and possibly expansion rules.
Criteria for choosing
The choice of material is made based on multiple criteria. In most cases, local authorities impose types of roofs based on architectural or environmental constraints.
The choice of material and/or the implementation of an installation technique will depend on:
The slope of the slope in % or °
The ground projection of the slope considered in meters
Its geographical location (climate zone defined by maps taking into account the combination of rain/wind or mountainous area, etc.)
Its local geographical location (climatic site)
Snow and wind mechanical constraints (rules and NV 65 map)
Local environmental constraints (aesthetic, architectural, etc.)
Three climatic zones
Zone I consists of the entire interior of the country, the Mediterranean coast, and altitudes below 200 m.
Zone II includes the Atlantic coast within 20 km deep and altitudes between 200 and 500 m.
Zone III includes the Atlantic, Channel, and North Sea coasts within 20 km deep and altitudes above 500 m.
Three situations
The building's location relative to the environment overlaps with the climatic zone.
A sheltered site corresponds to a construction in the hollow of a basin surrounded by hills on all sides and thus protected from the wind.
A normal site is a plain or plateau with little variation in elevation.
An exposed site is where the buildings are located on the coast up to about 5 km deep, on the tops of cliffs, in estuaries or enclosed bays, and, inland, in narrow windy valleys, on isolated or high mountains.
Roofing at high altitudes
Mountain buildings (above 900 m) require a "double roof" composed of several layers. The large temperature differences between outside/inside and night/day cause phenomena such as dew point (Condensation) and freeze/thaw harmful to building preservation.
Interior condensation, often invisible, damages coatings and causes mold. It results from the low temperature inside the walls combined with a high humidity level.
Freeze/thaw causes the formation of extremely heavy icicles at the edge of the slopes, dangerous for pedestrians and destructive for materials. The phenomenon is simple: heated from below, the snow melts, flows between the slope and the snow cover, then freezes passing over the overhangs of the roof exposed to the cold air. Tons of ice can accumulate.
The "double roof" is the most effective way to counteract these drawbacks. The complex consists of:
A vapor barrier is placed at the ceiling of the rooms in the sloping ceiling. Acting as a barrier to vapor, it prevents it from entering the insulation and condensing inside it.
Above, the thermal insulation prevents the temperature of the wall from dropping, reducing the risk of interior condensation.
The insulation is then coated with waterproofing to protect it from condensate from the roof. – An air gap circulates between the waterproofing and the roof elements. It must be at the outside temperature to prevent thaw/refreeze. In some cases, linear ventilation "ridge gutter" will be implemented. – Finally, the actual roofing is carried out.
In order:
Rafters
Thin insulation
Counter batten
27 mm deck board
Cabrons
Tar insulation
Pressure-treated counter batten
4*10 pressure-treated basting
Non-felted corrugated steel fixed in corrugated steel + "snow stops"
Rules and techniques of implementation
The design and implementation of roofs are subject to the rules of the trade, standards, and technical opinions of official bodies as well as the installation advice from manufacturers.
In france
The design and implementation of roofs are subject to DTU (Document Technique Unifié) regulations in the 40 series. In the absence of official standards, Technical Assessments (ATec) are taken into account.
DTU 40.11 Slate Roofing
DTU 40.13 Fiber Cement Slate Roofing
DTU 40.21 Interlocking or Sliding Clay Tile Roofs with Relief
DTU 40.211 Clay Tile Roofs with Flat Gauge
DTU 40.22 Canal Clay Tile Roofing
DTU 40.23 Flat Clay Tile Roofs
DTU 40.24 Concrete Tile Roofing with Sliding and Longitudinal Interlocking
DTU 40.241 Concrete Flat Tile Roofing with Sliding and Longitudinal Interlocking
DTU 40.25 Concrete Flat Tile Roofing
DTU 40.35 Ribbed Sheet Roofing from Coated Steel Sheets
DTU 40.36 Pre-painted or Non-pre-painted Aluminum Sheet Roofing
DTU 40.41 Roofing with Metal Elements in Zinc Sheets and Long Sheets
DTU 40.44 Roofing with Metal Elements in Stainless Steel Sheets and Long Sheets
DTU 40.45 Roofing with Metal Elements in Copper Sheets and Long Sheets
DTU 40.46 Lead Roofing on Continuous Support
DTU 40.5 Rainwater Disposal Works
Roofer's vocabulary
In addition to the technical terms used by roofers, there are names for tiles used for finishing, decoration, and waterproofing of roofs. Here are the main terms to better understand the language of architects, builders, or roofers.
Hip: protruding line formed by the intersection of two roof slopes.
Brisé: the lower part of a Mansard roof.
Cabrons: over-rafter wooden profiles that create waves under flexible covering.
Chanlatte: beveled wooden lath, nailed on the rafters at the edge of the roof to compensate for the missing tile thickness in the first row (tilting). It can be replaced by a double batten.
Pet door: Metal or clay elements designed for roof and attic ventilation.
Coffin: (or cofine) tile or slate curved in the width direction.
Double tile: double row of tiles or slate, laid on the chanlatte, which makes up the roof edge. Also called a battlement.
Eaves: lower edge of a slope often equipped with a gutter.
Ridge tile: half-round or angular tile that covers the horizontal beam, called "ridge," placed at the junction of two slopes of a roof.
Standing seam: roofing and facade covering technique using waterproof metal.
Gambrel tile: tile curved inward in the width direction.
Left-handed tile: tile curved in length on its left edge, called "left to left," or right, called "left to right."
Giron tile: trapezoidal tile for making turrets, towers, or domes.
Lantern: ventilation cap that finishes an air intake, a vent, etc.
Batten: wooden strip nailed to the rafters that receives the tile hooks, commonly called a "roof batten."
Valley: inward ridge between two roof slopes.
Hanging tile: tile curved in the length direction.
Finial: decorative clay element that crowns the point of intersection of a ridge and hips, hips with each other if there is no ridge, or the top of a conical roof.
Gauge: visible part of the tile or slate that is completely wetted by rainwater. It corresponds to the spacing of the battens.
Bargeboard: the end of the roof on the gable side.
See also
Timber roof truss
Eavesdrip
Roofer
Glossary of architecture
Rain gutter
References
Building materials
Roofing materials
Roofs | Covering (construction) | [
"Physics",
"Technology",
"Engineering"
] | 4,793 | [
"Structural engineering",
"Building engineering",
"Architecture",
"Structural system",
"Construction",
"Materials",
"Roofs",
"Matter",
"Building materials"
] |
76,723,510 | https://en.wikipedia.org/wiki/Ultrasound-enhanced%20chemiluminescence | Chemiluminescence is the emission of light through a chemical reaction. It contrasts with fluorescence, which is excited by a light source. During chemiluminescence, the vibrationally excited product of an exoergic chemical reaction relaxes to its ground state with the emission of photons. Since the process does not require excitation light, problems in its application caused by light scattering or source instability are absent, and there is no concern about autofluorescence in the background, which can lead to highly sensitive deep tissue imaging.
Recently, many advances have been made in deep tissue optics regarding ultrasound modulated fluorescence and ultrasound switchable fluorescence. With its greater potential in medical imaging, ultrasound-enhanced chemiluminescence (UECL) has been developed as a second generation of chemiluminescence, and overcomes several limitations of chemiluminescence in deep tissue imaging. The simultaneous use of ultrasound and chemiluminescence imaging techniques helps accurately visualize the tissue of interest in dual imaging. Additionally, ultrasound can serve as an efficient tool to enhance the intensity of chemiluminescence by reducing light scattering while increasing spatial resolution.
Chemiluminescent materials
Luminol
Luminol (5-amino-2,3-dihydrophthalazine-1,4-dione) exhibits strong chemiluminescent properties. Usually found as a solid or powder, luminol appears as a white to yellowish crystalline solid. It is soluble in water and relatively stable at room temperature without luminescence. Luminol must be activated with an oxidant to produce luminescence; hydroxide ions or hydrogen peroxide(H2O2) usually serve as activators. Laboratory settings often use potassium ferricyanide or potassium periodate for the catalyst. The catalyst can be the iron in hemoglobin in blood forensic detection, while enzymes in biological systems can also serve as catalysts in tissue imaging. However, the quantum yield of luminol does not exceed 1.5% in aqueous systems, and 5% in dimethylsulfoxide. The peak wavelength of luminescence emission varies across different solvent environments. Specifically, in aqueous solutions, the peak wavelength of luminescence emission is measured at 425 nm.
Coelenterazine
Coelenterazine is derived from coelenterate. It possesses a superoxide anion in its structure, which enables it to produce chemiluminescence. Unlike luminol, coelenterazine does not require any catalyst to trigger luminescence. Analogs of coelenterazine such as CLA (2-methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one) and MCLA (2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin-3-one) have been prepared and used in many research works. In contrast to luminol, MCLA is cell impermeable and is more useful in the detection of superoxides outside the cell. Moreover, coelenterazine and its analogs could be applied as prosthetic groups of various photoproteins like mnemiopsin, aequorin, and beroverin. Coelenterazine has been used often in cancer imaging. In recent works, coelenterazine is used to estimate the elevated levels of ROS produced by cancer cells. Coelentarizine is also used in the detection and imaging of chronic inflammation associated with inflammatory bowel disease.
Acridinium esters
Acridinium esters are a class of compounds with an acridinium structure, which emit strong light signals in chemiluminescent reactions. They are commonly used in biomedical detection and analysis as luminophores or substrates in chemiluminescence assays. Acridinium does not require a catalyst to produce chemiluminescence. Hydrogen peroxide (H2O2) and a strong base are sufficient to cause acridinium esters to produce chemiluminescence. Acridinium phenyl esters display greater luminescence than simple acridinium alkyl esters. Compared to other chemiluminescent materials, acridinium derivatives have the advantage of displaying quick light emission with simple chemical triggers. The main disadvantage of acridinium (phenyl) esters is their instability in the aqueous medium, as the ester bond between the acridinium ring and the phenol undergoes hydrolysis.
Mechanism of UECL
A chief concern for chemiluminescence is that the scattering light increases the noise of the detection. Consider the redox reaction of H2O2:
It can be inferred that, with the appearance of oxidizing agents in tissues, free HO• radical is also produced. One could locally increase the production of H2O2 or free HO• of the target tissue while reducing those in the nearby medium to increase signal-to-noise ratios.
A study conducted at 10–3 molar luminol and 10–4 molar H2O2 showed that the intensity of sonochemiluminescence (ISCL) was linearly increased with the increase of ultrasound power up to 100 W.
It is proposed that water and oxygen molecules were freed and more local free radicals were created at the air-liquid interface of the bubbles' cavitation caused by ultrasound. The process can be described in equations as:
In further studies, it has been shown that focused ultrasound creates periodic compression and rarefaction of tissues, which can lead to changes in the local refractive index in tissues and allow less optical absorption and scattering. One can also modulate the laser light with a different frequency of ultrasound. Tissues will oscillate with different ultrasound frequencies and consequently produce harmonic interference with the laser. Simultaneously, photon-photon interaction will modulate the frequency of the transmitted laser, making the laser transverse deeper into tissues with less reflection.
Effects of ultrasound on chemiluminescent signals
As discussed under "Mechanism", the intensity of sonochemiluminescence (ISCL) was correlated to free radical HO• concentration and is linearly proportional to the ultrasound power. More interestingly, the effective distances are also strongly dependent on the alignment of ultrasound waves, which means that the more focused the delivered ultrasound, the less scattered the luminescent light would be, which therefore leads to a higher resolution. Although the mechanism behind this is still unclear, research has shown that temperature increases could enhance the sensitivity of chemiluminescence. This might be because the temperature of focal points is increased locally by the ultrasound.
It is also reported that the chemiluminescent signals could be greatly enhanced at a distance of 2–8 mm depending on the power of ultrasound. The proposed mechanism is that ultrasonication produces H2O2 which subsequently stabilizes the short-lived free radicals HO•.
Concerns
The major concern regarding ultrasound-enhanced chemiluminescence is the local heat generated by the ultrasound. Although the local heat could enhance the intensity and resolution of chemiluminescence images, producing heat beyond the endurance of cells can lead to tissue damage. To avoid the risks of overheating the tissues, the duration of exposure should be optimized. However, the primary cells in tissues are vulnerable to heat, and focused ultrasound-enhanced chemiluminescence has very limited ability to control local heat, there needs to be a detailed investigation into methods to overcome this limitation.
See also
Chemiluminescence
Eclox
luminescence
Bioluminescence
References
Chemiluminescence | Ultrasound-enhanced chemiluminescence | [
"Chemistry"
] | 1,605 | [
"Luminescence",
"Chemiluminescence"
] |
76,723,533 | https://en.wikipedia.org/wiki/Matrix%20mortality%20problem | In computer science, the matrix mortality problem (or mortal matrix problem) is a decision problem that asks, given a finite set of n×n matrices with integer coefficients, whether the zero matrix can be expressed as a finite product of matrices from this set.
The matrix mortality problem is known to be undecidable when n ≥ 3. In fact, it is already undecidable for sets of 6
matrices (or more) when n = 3, for 4 matrices when n = 5, for 3 matrices when n = 9, and for 2 matrices when n = 15.
In the case n = 2, it is an open problem whether matrix mortality is decidable, but several special cases have been solved: the problem is decidable for sets of 2 matrices, and for sets of matrices which contain at most one invertible matrix.
Notes
Undecidable problems
Unsolved problems in computer science
Unsolved problems in mathematics
Matrix theory | Matrix mortality problem | [
"Mathematics",
"Technology"
] | 195 | [
"Unsolved problems in mathematics",
"Unsolved problems in computer science",
"Computational problems",
"Computer science stubs",
"Computer science",
"Undecidable problems",
"Computing stubs",
"Mathematical problems"
] |
76,726,100 | https://en.wikipedia.org/wiki/N103B | N103B (also known as SNR 0509–68.7) is a supernova remnant located in the Large Magellanic Cloud. It is relatively close to Earth, allowing astronomers to observe and study the remnant. It lies a short distance from NGC 1850. The exact type of supernova that produced N103B is under speculation, but has been widely accepted to be a Type Ia supernova. It is within the boundaries of the constellation Mensa.
Morphology
The orange-red filaments visible in the image show the shock fronts of the initial supernova explosion. These filaments have allowed astronomers to calculate the original barycenter of the explosion. The filaments also show that the explosion is no longer expanding as a sphere, but is elliptical in shape. Astronomers assume that part of material ejected by the explosion interacting with an extremely dense cloud of interstellar material, which slowed its speed. N103B is theorized to be interacting with dense circumstellar matter.
A double-ring structure is visible within N103B, implying that it expands into an hourglass-shaped cavity and forms bipolar bubbles.
Supernova
Using the Chandra Telescope, astronomers observed N103B to figure out the initial supernova type. Due to the type of material and the amount of specific materials within N103B, astronomers were able to support the widely accepted belief that it was formed from a Type Ia supernova.
See also
List of supernova remnants
List of supernovae
External links
N103B at NED
References
Supernova remnants
Large Magellanic Cloud
Mensa (constellation) | N103B | [
"Astronomy"
] | 331 | [
"Mensa (constellation)",
"Constellations"
] |
76,726,515 | https://en.wikipedia.org/wiki/Behavioral%20economics%20and%20public%20policy | Behavioral economics and public policy is a field that investigates how the discipline of behavioral economics can be used to enhance the formation, implementation and evaluation of public policy. Using behavioral insights, it explores how to make policies more effective, efficient and humane by considering real-world human behavior and decision-making.
Overview
Behavioral economics as a subfield of economics is a fairly recent development and the implications of it for public policy have yet to be systematically explored. Behavioral economists have accumulated extensive findings indicating, contrary to standard economic assumptions, that people do not act rationally, that they are not perfectly self-interested, and that they hold inconsistent preferences. These deviations from the standard assumptions about behavior have become increasingly more important for economic policy in recent years. In the book Policy and Choice: Public Finance through the Lens of Behavioral Economics economists William J. Congdon, Jeffrey R. Kling and Sendhil Mullainathan argue that though traditional public finance provides a comprehensive framework for policy analysis, insights from behavioral economics can be applied to questions of economic policy, such as tax policy, pension systems, health policy, and other government interventions.
Use of behavioral insights
Taxation
Traditional public finance has a well-developed framework for determining how to set taxes optimally. One broad insight is that efficient taxes are those that minimally distort consumer choices, because a change in choices resulting from taxation represents a welfare cost. Behavioral economics complicates this logic.The behavioral concept of "tax salience" refers to the visibility of the tax-inclusive price and how the way taxes are displayed can influence consumer behavior. It emphasizes that people are more likely to change their behavior in response to highly visible and highly salient taxes. Commodity taxes that are included in the posted prices that consumers see when shopping have larger effects on demand. On the other hand, individuals may fail to attend to sales taxes that are not included in the prices on store shelves but are computed at the register (such as in the United States) – they are not salient at the time of choice.
Tax non-salience should represent an opportunity for governments of raising revenues without distorting behavior. But the lack of response to a non-salient tax is not the same as lack of response to a salient tax. It means that consumers make choices as if an item costs $X, but in reality they spend $X + $Y. As a result, they have $Y less to spend in the future than they had planned. If the lost money is treated as a pure income effect (individuals see that they have $Y less to spend on all other goods and adjust), then that would turn the non-salient tax into a lump-sum tax and governments should use non-salient taxes heavily. But rather than thinking of their overall budget as depleted by $Y, individuals could also think of $Y as depleting their grocery budget specifically, and they may spend $Y less during their next shopping. Or they may never change consumption and instead end up saving less. In such cases, the low demand response to non-salient taxes is misleading: though it does not generate distortions in the demand for the good being taxed, it is creating possibly higher distortions elsewhere. So governments would need to take into account other potential demand responses before using non-salient taxes.
Retirement and pension systems
Old-age insurance and savings policies can help to ensure adequate levels of consumption in old age by assisting individuals with accumulating adequate wealth during their working years. A behavioral approach offers new perspectives on how to effectively accomplish that. Behavioral economics recognizes that individuals often have trouble saving and planning for their own retirement – they save too little, they invest in the wrong assets, etc. If low levels of saving are simply due to it being unattractive relative to consumption, then subsidization, such as through existing tax incentives, is sufficient. But if low levels reflect choice errors or a failure of self-control, subsidies may not be sufficient or necessary. The key implication is that if policy seeks to encourage more saving, it can do so by making it easier to save. In enrollment in retirement saving plans, behavioral economics has shown that default rules (actively enrolling or automatically enrolled, with the ability to opt out) can have substantial effects on participation and saving. Policies encouraging firms to automatically enroll their workers in 401(k) plans, rather than waiting for individuals to sign up on their own, seem to encourage participation and savings to an extent that is difficult to rationalize under standard assumptions about preference and choice. Alternatively, forcing individuals to choose or dramatically simplifying the enrollment process also increases participation and saving. Simplifying the process of opening and contributing to other types of retirement accounts, such as IRAs, could have similar effects.
To address that part of low saving that results from the difficulty that individuals can have in exerting self-control, policy might seek to aid individuals in committing to saving and make it harder for them to procrastinate or give in to short-term temptations. Policies can assist individuals with following through on their intentions through automatic enrollment and automatic escalation, which have been shown to be effective tools. Further, when individuals are tempted to use their retirement funds before they retire, policies can reduce the temptation through penalties and fees that are features of most existing tax-favored retirement savings plans. Policies can also seek to expand individuals' capacity to make good choices through education and efforts to promote financial literacy.
Health insurance
Public finance focuses on the possibility that unregulated markets for health insurance are susceptible to failure and inefficiency due to asymmetries of information that occur when some market participants have more complete information than others about relevant market features. One of them is adverse selection. Consumers have private information about their health status that insurers do not and the resulting selection effect in consumption can cause the market to unwind. Policymakers can encourage or even force risk pooling (insurance companies coming together to form one) through regulating and subsidizing private insurance markets, or they can provide fully public insurance. However, individuals may be imperfect optimizers or may hold non-standard preferences. Decision-making errors such as overconfidence, difficulty in evaluating risks and making judgments under uncertainty mean that the private information associated with health status may not necessarily translate into the sort of adverse selection predicted by the traditional model. Moreover, some behavioral tendencies that might mitigate adverse selection might also lead to decision-making errors that themselves lead to a loss of welfare. The net impact of behavioral tendencies on the market for health insurance is theoretically unclear. Therefore, the success or failure of policy responses to increase access to health insurance might depend on how the policies address issues related to individual choice.
Another asymmetry is moral hazard. While moral hazard suggests that people with insurance will overconsume drugs or doctor visits, self-control problems might deter individuals from doing so or even lead them to underconsume those services. In drawing conclusions about the social welfare implications of alternative policies for expanding health insurance, the costs associated with moral hazard must be considered in context rather than assumed to follow from behavior consistent with standard assumptions.
The policy response to adverse selection and moral hazard must consider the ways in which behavioral tendencies affect how those forces operate. One approach is to promote the function of private health insurance markets through a combination of subsidies that make health insurance more affordable and regulations that encourage pooling and discourage selection, both in group and nongroup health insurance markets. Another is to provide health insurance coverage directly through public programs, which can target vulnerable populations and can be explicitly designed to pool risks and avoid adverse selection. The psychology of targeted individuals plays an important but distinct role in the operation of each type of policy environment.
Use of behavioral insights
unemployment benefits (behavior under coverage that looks much like standard moral hazard may be a result of behavioral tendencies such as failure of self-control or reference-dependent preferences).
education (more immediate incentives, short-run, salient incentives)
environmental policy (short-run, salient incentives, clear messages)
provision of public goods (policy can foster conditions under which individuals will provide or contribute to public goods on a voluntary basis)
poverty and inequality (moral hazard, distinguishing properly who requires assistance)
Future directions
In the future, behavioral economics has a great potential to aid in the field of public policy. Psychological factors reshape core concepts in public finance and can be integrated into policy making and improve the outcomes of policies. However, further research is needed. For instance, resolving the net welfare consequences of tax salience is an important future line of research. The net impact of behavioral tendencies on the market for health insurance is theoretically unclear and also requires further study.
References
Further reading
Bhargava, Saurabh; Loewenstein, George (2015). "Behavioral Economics and Public Policy 102: Beyond Nudging". The American Economic Review. 105 (5): 396–401.
Mullainathan, Sendhil; Schwartzstein, Joshua; Congdon, William J. (2012). "A Reduced-Form Approach to Behavioral Public Finance". Annual Review of Economics. 4: 511–540. .
Amir, On; Ariely, Dan; Cooke, Alan; Dunning, David; Epley, Nicholas; Gneezy, Uri; Koszegi, Botond; Lichtenstein, Donald; Mazar, Nina; Mullainathan, Sendhil; Prelec, Drazen; Shafir, Eldar; Silva, Jose (2005). "Psychology, Behavioral Economics, and Public Policy". Marketing Letters. 16 (3/4): 443–454.
Public finance
Behavioral economics
Public policy | Behavioral economics and public policy | [
"Biology"
] | 1,979 | [
"Behavior",
"Behavioral economics",
"Behaviorism"
] |
76,726,692 | https://en.wikipedia.org/wiki/G306.3-0.9 | SNR G306.3-00.9, also called G306.3-0.9 is a supernova remnant located in the constellation Centaurus. It was discovered by the Swift Space Observatory in 2011.
Morphology
The first observations carried out with the Chandra X-ray Observatory revealed that SNR G306.3-00.9 has a distorted morphology, brighter towards the southwest. The strong radio and X-ray emission from this area suggests either that there is interaction with an interstellar cloud or that it is the consequence of an asymmetric supernova explosion. Emission from highly ionized atoms of magnesium, silicon, sulfur and argon, and suggests that it is the remnant of a type Ia supernova. Such a spectrum can be described by a non-equilibrium ionization plasma with a temperature below 1 keV. In infrared images at 24 μm, the morphology of the dust grains impacted by the shock wave is shell-shaped, coinciding with the distribution observed in hard X-rays. At 70 μm the dust emission is concentrated in the south, with very little dust in the northwest.
Distance
The age of SNR G306.3-00.9 is not well known. It was initially estimated that it could be approximately 2,500 years old—a very young supernova remnant—considering that it was 8,000 parsecs away. A later study, which compares the X-ray absorption column with the distribution of H I decomposed along the line of sight, gives it a distance of around 20,000 parsecs, so its age may be 6000 years and evolutionarily it would be in the late Sedov phase. According to this, the most probable location of SNR G306.3-00.9 is in the outer extension of the Perseus arm. However, according to other models, its age could be considerably older, 12,800 (+2500, − 2500) years.
See also
List of supernova remnants
2011 in science
References
Supernova remnants
Centaurus | G306.3-0.9 | [
"Astronomy"
] | 421 | [
"Centaurus",
"Constellations"
] |
76,727,571 | https://en.wikipedia.org/wiki/G54.1%2B0.3 | SNR G054.1+00.3, also called G54.1+0.3, 2E 4258 and 2E 1928.3+1846 is a supernova remnant located in the constellation Sagittarius. It was identified as a supernova remnant in a study of the galactic plane in the radio continuum at wavelengths of 21 and 11 cm.
Morphology
SNR G054.1+00.3 is identified as a supernova remnant by its non-thermal radio emission with strong linear polarization. It has a small angular radius (1.5 arcminutes) in radio and X-ray images. Its X-ray emission has been detected with the Einstein, ASCA, ROSAT and Chandra telescopes. In this region of the electromagnetic spectrum it presents different structures that include a ring, an outer nebula and a pulsar, called PSR J1930+1852. The period of this pulsar is 136 ms and it emits very high energy gamma rays. There is a nebula caused by the stellar wind coming from it (PWN).
CO observations show that there is no interaction between SNR G054.1+00.3 and the surrounding clouds and that it instead appears to be located within a bubble. Likewise, in a study carried out in the infrared region at 21 μm, features similar to those observed in Cassiopeia A appear, probably attributable to SiO2 grains. Recently formed cold dust (with a temperature of only 27 - 44 K) has also been detected.
Various models that consider the amount of dust and its composition suggest that the progenitor star was part of a massive star cluster and had a mass of 15 - 20 solar masses or 16 - 27 solar masses.
Distance
SNR G054.1+00.3 is a young supernova remnant. According to various studies, it has an age between 2100 and 3600 years, between 1500 and 3000 years, or 1700 years. On the other hand, the distance at which it is located is not well known either. Various works place this supernova remnant at a distance between 5,000 and 10,000 parsecs; a commonly accepted value is 6200 (+3800, -1200) parsecs.
See also
List of supernova remnants
Lists of astronomical objects
References
Supernova remnants
Sagittarius (constellation) | G54.1+0.3 | [
"Astronomy"
] | 490 | [
"Sagitta",
"Constellations"
] |
76,728,025 | https://en.wikipedia.org/wiki/Balsamia%20luyashanensis | Balsamia luyashanensis is a species of fungus from the genus Balsamia. It was previously placed in the genus Barssia.
References
Pezizales
Fungus species | Balsamia luyashanensis | [
"Biology"
] | 38 | [
"Fungi",
"Fungus species"
] |
76,728,069 | https://en.wikipedia.org/wiki/Barssia%20peyronelii | Barssia peyronelii is a species of fungus from the genus Barssia.
Distribution
Barssia peyronelii is primarily found in Northern Italy.
References
Pezizales
Fungus species
Fungi described in 1936
Fungi of Italy | Barssia peyronelii | [
"Biology"
] | 49 | [
"Fungi",
"Fungus species"
] |
76,728,097 | https://en.wikipedia.org/wiki/Balsamia%20maroccana | Balsamia maroccana is a species of fungus from the genus Balsamia.
Location
Balsamia maroccana is primarily found in Morocco as its name suggests.
References
Fungus species
Pezizales
Fungi of Africa | Balsamia maroccana | [
"Biology"
] | 47 | [
"Fungi",
"Fungus species"
] |
76,728,109 | https://en.wikipedia.org/wiki/Balsamia%20hellenica | Balsamia hellenica is a species of fungus from the genus Balsamia. It was previous placed in genus Barssia.
References
Pezizales
Fungus species
Fungi of Greece
Fungi described in 2015 | Balsamia hellenica | [
"Biology"
] | 42 | [
"Fungi",
"Fungus species"
] |
76,729,401 | https://en.wikipedia.org/wiki/Kesteven%2075 | Kesteven 75, abbreviated as Kes 75 and also called SNR G029.7-00.3, G29.7-0.3 and 4C -03.70, is a supernova remnant located in the constellation Aquila.
Morphology
Kesteven 75 is a supernova remnant of composite morphology. In the radio band, it shows a shell or partial shell of about 90 arcseconds in radius, with a central nebula of about 25 × 35 arcseconds. The complete absence of emission in the eastern part indicates a strong density gradient of the interstellar medium where Kesteven 75 expands. The central component has been observed to have a flat radio spectrum with substantial polarization, which is characteristic of a pulsar or plerion wind nebula. The expansion speed of this plerion is approximately 1000 km/s.
X-ray observations with the ASCA and Chandra observatories also show the composite nature of Kesteven 75, its morphology being very similar to that of radio frequencies. The emission from the shell of Kesteven 75 is mainly concentrated in two regions, to the southeast and southwest. Likewise, a "jet"-torus structure, common in young plerions, has been identified. According to certain observations of Chandra, the spectra of the shell can be explained by a thermal model of two temperatures, possibly associated on the one hand with the impacted material, and on the other with the ejecta material that has suffered a second impact due to the reverse shock.
The infrared emission from the shell is spatially correlated with the X-ray emission, suggesting that the dust particles are heated by the collision of gas previously heated by the X-rays. This dust reaches a temperature of 140 K due to upon collision with a hot and relatively dense plasma.
Kesteven 75 has also been detected in the gamma ray region between 20 and 200 keV with the INTEGRAL space observatory, and between 0.3 and 5 TeV with the H.E.S.S telescope system.
Progenitor
Based on the high velocity of the ejecta and the low density implied by the initially estimated distance (much greater than currently accepted), it has been suggested that Kesteven 75 comes from a type Ib/c supernova explosion. However, subsequent studies have proposed that Kesteven 75 is probably the result of a more common type IIP supernova, where the plerion expands into an asymmetric nickel bubble. The parent star is thought to have a mass between 8 and 12 solar masses.
Stellar remnant
Kesteven 75 houses the X-ray pulsar PSR J1846−025, discovered in 2000, which provides energy to the plerion. It is a highly energetic stellar remnant (E = 8.3 × 1036 erg/s) whose rotation period is 325 ms. In 2006, it was detected that this pulsar was in an "active" or "flaring" state, which led to changes in its spectrum, as well as in the morphology of the associated plerion; Fourteen years later, activity was detected again in PSR J1846−025. However, the energetic and spectral properties of this pulsar firmly distinguish it from a magnetar. Its inferred magnetic field (Bs = 4.9 × 1013 G) is the largest among this type of objects, and is probably responsible for the activity intervals discovered, suggesting a transition to a magnetar state.
Distance
Although historically estimates of the distance to Kesteven 75 have varied significantly between 5,000 and 21,000 parsecs, recent analyzes based on H I observations place this supernova remnant at 5,800 ± 500 parsecs from Earth. On the other hand, Kesteven 75 is a very young supernova remnant, with an age of less than 840 years. The study of the expansion of the plerion over 10 years has allowed us to limit the age of this remnant to 480 ± 50 years . Consequently, Kesteven 75 contains the youngest plerion in our galaxy.
See also
List of supernova remnants
External links
Kesteven 75 at SIMBAD
References
Supernova remnants
Aquila (constellation) | Kesteven 75 | [
"Astronomy"
] | 866 | [
"Aquila (constellation)",
"Constellations"
] |
76,732,045 | https://en.wikipedia.org/wiki/NGC%20673 | NGC673 is an intermediate spiral galaxy in the constellation of Aries. Its velocity with respect to the cosmic microwave background is 4894 ± 20km/s, which corresponds to a Hubble distance of . In addition, 31 non redshift measurements give a distance of . The galaxy was discovered by German-British astronomer William Herschel on 4 September 1786.
According to A.M. Garcia, NGC 673 is the namesake of the NGC 673 Group (also known as LGG 31). This group contains at least 17 galaxies, including IC 156, IC 162, NGC 665, NGC 677, NGC 683, and 11 galaxies from the UGC catalogue.
Supernovae
Two supernovae have been observed in NGC 673:
British amateur astronomer Mark Armstrong, K. Okazaki, Kahoku-machi, and Yamagata-ken discovered SN1996bo (typeIa, mag. 16.5) on 18 October 1996.
LOTOSS (Lick Observatory and Tenagra Observatory Supernova Searches) discovered SN2001fa (typeIIn, mag. 16.9) on 18 October 2001.
See also
List of NGC objects (1–1000)
References
External links
0673
061315
+02-05-033
01259
01457+1116
Aries (constellation)
17860904
Discoveries by William Herschel
Intermediate spiral galaxies | NGC 673 | [
"Astronomy"
] | 293 | [
"Aries (constellation)",
"Constellations"
] |
76,732,147 | https://en.wikipedia.org/wiki/Tiazotic%20acid | Tiazotic acid (brand names Thiotriazoline and Tiokor) is an antioxidant. It is used as a pharmaceutical drug for the treatment of ischemic heart disease in Russia, Ukraine, and Uzbekistan.
It is used as its salt with morpholine.
It has been studied for its potential to improve the cardiac effects of COVID-19.
References
Drugs acting on the cardiovascular system
Triazoles
Thioethers
Carboxylic acids | Tiazotic acid | [
"Chemistry"
] | 99 | [
"Carboxylic acids",
"Functional groups"
] |
69,316,238 | https://en.wikipedia.org/wiki/WR%20120 | WR 120 is a binary containing two Wolf-Rayet stars in the constellation of Scutum, around 10,000 light years away. The primary is a hydrogen-free weak-lined WN7 star, the secondary is a hydrogen-free WN3 or 4 star, and the system is a possible member of the cluster Dolidze 33. From our point of view, WR 120 is reddened by 4.82 magnitudes, and it has the variable designation of V462 Scuti.
Properties
Analysis of the primary's spectrum with PoWR shows that it has a temperature of around 50,000 Kelvins, and is losing mass at a rate of /year, or 1 solar mass every 80,000 years, which is being carried away from the surface at a speed of 1,225 kilometres per second. Taking its close distance into account, WR 120 A's luminosity turns out to be a mere , which would make it one of the dimmest WN stars known, and one of the only WN stars with a luminosity below . Using the Stefan-Boltzmann Law, a radius of is derived, and a "transformed" radius at an optical depth of 2/3, more comparable to other types of stars, is at about . Using the WR Luminosity-Mass ratio, WR 120 may have a mass of just , one of the lowest masses of any WR star. WR 120 A’s visual luminosity is , which is also on the lower end of WR visual luminosities.
WR 120 is thought to be a member of Dolidze 33, an open cluster nearly 3,000 pc away.
Binarity
In 2021, WR 120 was revealed to be a binary star. Previously, it was thought to be a single WR star, but it is in fact a rare double Wolf-Rayet star. The companion (a WN3/4 WR star) is located approximately 1700 AU from the primary WN7 WR, and is about 2.1 magnitudes fainter than WR 120.
References
Wolf–Rayet stars
Scuti, V462
Scutum (constellation) | WR 120 | [
"Astronomy"
] | 442 | [
"Scutum (constellation)",
"Constellations"
] |
69,317,325 | https://en.wikipedia.org/wiki/Lithium%20telluride | Lithium telluride (Li2Te) is an inorganic compound of lithium and tellurium. Along with LiTe3, it is one of the two intermediate solid phases in the lithium-tellurium system. It can be prepared by directly reacting lithium and tellurium in a beryllium oxide crucible at 950°C.
References
Lithium compounds
Tellurides
Fluorite crystal structure | Lithium telluride | [
"Chemistry"
] | 82 | [
"Inorganic compounds",
"Inorganic compound stubs"
] |
69,317,845 | https://en.wikipedia.org/wiki/Animal%20perception%20of%20magic | Researchers study the reactions of animals observing humans performing magic tricks in order to better understand animal cognition. Using these studies, evolutionary psychologists aim to gain insights into the evolution of perception and attention by comparing responses of different species, including humans.
Background
Magic is about violating expectations. It capitalises on specific blind spots in attention and perception. While scientific interest in humans' perception of magic dates back to the late 19th century, when in 1896 Alfred Binet presented his work, this faded quickly, and has only recently, in the early 21st century, been revived. Some researchers have coined terms such as neuromagic or magicology for the study of magic. Other scientists are critical of the new field, saying it is not worthy to stand as a field of its own. Scientists aim to get insight into how the human mind operates.
Some animal species are capable of misdirection, an important skill magicians possess to trick humans. For example, chimpanzees have been observed to deliberately look away from an object they desire as to avoid it being noticed by a competitor. Jays and other corvids pretend to store food in various places, trying obscure the cache's true location from observers. This suggests that at least some species are susceptible to magic.
Overview
In an article in Science in 2020, researchers Garcia-Pelegrin, Schnell, Wilkins, and Clayton made the case for using magic in the study of animal cognition. They argued that it offers a new way for hypothesis testing and experimental design. Their central research questions are: can a magic trick that deceives humans fool animals as well? If so, how? Various practical challenges exist to answer these questions. Attention control is a key component of many magic tricks and getting the animal to pay attention to a human can be difficult and might limit the range of species and magic tricks that can be used in studies. A further challenge is how to assess if the magic trick worked or not. In the absence of verbalisations researchers have to look for behavioural responses indicating whether the animal has been tricked or not. In humans, successful magic tricks elicit an emotional response of surprise. Researchers assume that a relatively long time of looking at an object or situation is an indication of the animal being surprised by what happened.
Known cognitive skills, such as the ability to grasp object permanence, that is, the ability to represent objects in the mind's eye when the object is out of sight, can inspire the researchers which tricks to perform on which species. Animals that cache their food seem suitable subjects for tricks exploiting blind spots in object permanence.
By studying nonhuman animals' perception of magic, we can gain insights into the evolution of the cognitive skills magicians exploit.
Results
Jays
Schnell et al. found evidence in a 2021 study that jays are sensitive to magic. They used the cups and balls routine to trick the birds. In a second study they performed three magic tricks, palming, the French drop, and fast pass, on six jays. The birds were not deceived by the palming and French drop tricks, but were deceived by the fast pass. The first two techniques depend on human hand movements setting expectations for an object moving from one place to another. These hand movements did not trick the jays. But fast hand movements did mislead them.
References
Sources
Design of experiments
Ethology
Animal cognition
Magic tricks | Animal perception of magic | [
"Biology"
] | 693 | [
"Behavior",
"Animals",
"Behavioural sciences",
"Animal cognition",
"Ethology"
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69,319,155 | https://en.wikipedia.org/wiki/TOLIMAN | The TOLIMAN (Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighbourhood) space telescope is a low-cost mission concept aimed at detecting of exoplanets via the astrometry method, and specifically targeting the Alpha Centauri system. TOLIMAN will focus on stars within 10 parsecs (32.6 light years) of the Sun. The telescope, still under construction, is expected to be launched into low Earth orbit no earlier than 2024. The mission will involve scientists of the University of Sydney, Saber Astronautics in Australia, Breakthrough Initiatives, and NASA's Jet Propulsion Laboratory.
According to the Mission Leader Peter Tuthill the launch is expected no earlier than the end of 2024.
TOLIMAN will explore all three components of the Alpha Centauri system in search of planets in the habitable zone.
References
External links
About the project at Breakthrough Initiatives
Exoplanet search projects
Proposed NASA space probes
Space astrometry missions
Space telescopes | TOLIMAN | [
"Astronomy"
] | 199 | [
"Astronomy projects",
"Exoplanet search projects",
"Space telescopes",
"Space astrometry missions"
] |
69,320,768 | https://en.wikipedia.org/wiki/Hanhee%20Paik | Hanhee Paik is a South Korean experimental quantum computing researcher who works for IBM Research at the Thomas J. Watson Research Center, where she helps develop superconducting devices for storing and operating on qubits.
Education and career
Paik has a master's degree from Yonsei University in South Korea, and completed a doctorate at the University of Maryland, College Park.
After postdoctoral research at the University of Maryland Laboratory for Physical Sciences, she took on another postdoctoral position at Yale University where she continued research in coherence and materials. In 2012, she left academia to become a researcher for BNN Technology PLC, specializing in quantum computing research. In 2014, she began her current position at IBM research. At IBM, her work has been included in the IBM Quantum Experience and IBM Q System One projects. As a Senior Research Scientist in quantum computing and quantum ecosystem development, she is continually developing new qubit architectures whilst also leading technical projects.
Paik's advancements pave a path forward within the industry of superconducting quantum computing for commercialization. Her invention proved that it is possible to commercialize superconducting quantum computing. Ten years later, IBM is running on average, 2 billion servers per day as a result of Paik's discoveries.
Recognition
In 2021, Paik was named a Fellow of the American Physical Society (APS), after a nomination from the APS Forum on Industrial & Applied Physics, "for pioneering a novel superconducting qubit architecture that catalyzed the commercialization of superconducting quantum computing, and for contributions to advance quantum computing research in the industry".
References
External links
Year of birth missing (living people)
Living people
South Korean women engineers
South Korean physicists
21st-century South Korean women scientists
Women physicists
Quantum physicists
Yonsei University alumni
University of Maryland, College Park alumni
Yale University faculty
IBM employees
Fellows of the American Physical Society | Hanhee Paik | [
"Physics"
] | 392 | [
"Quantum physicists",
"Quantum mechanics"
] |
69,323,201 | https://en.wikipedia.org/wiki/NGTS-3 | NGTS-3 is a star system located in the southern constellation Columba. With an apparent magnitude of 14.67, it requires a powerful telescope to observe. However, NGTS-3 is actually an unresolved spectroscopic binary system. The system is located approximately 2,480 light years away, based on parallax measurement, and is receding with a radial velocity of 8.57 km/s.
The system consists of two main sequence stars, classified as G6 and K1, respectively; however, only the properties of the primary star are known. NGTS-3A has a similar mass to that of the Sun, but is 7% smaller in radius. It radiates at 72% of the Sun's luminosity from its photosphere at an effective temperature of , which gives it the typical yellow hue characteristic of a G-type star.
Planetary System
In 2018, the NGTS survey discovered an inflated hot Jupiter orbiting NGTS-3A despite the components being visually unresolved.
References
G-type main-sequence stars
Columba (constellation) | NGTS-3 | [
"Astronomy"
] | 225 | [
"Columba (constellation)",
"Constellations"
] |
69,325,608 | https://en.wikipedia.org/wiki/Hexadecanal | Hexadecanal is an organic compound with the chemical formula C16H32O.
In biology
Hexadecanal is found in human skin, saliva, and feces. It has a calming effect on mice.
A 2017 study found that non-autistic men demonstrate an increase in electrodermal activity when exposed to subliminal levels of hexadecanal while men with autism spectrum disorder do not.
In 2021, inhalation of hexadecanal was found to reduce aggression in men but to trigger aggression in women. Hexadecanal is one of the most abundant substances emitted by human babies from their heads, which may be an evolutionary survival mechanism to induce mothers to defend the baby and fathers to not attack it. But it is not yet known whether the amount of hexadecanal emitted by humans is sufficient to affect other humans.
References
Alkanals | Hexadecanal | [
"Chemistry"
] | 185 | [
"Organic compounds",
"Organic compound stubs",
"Organic chemistry stubs"
] |
69,326,595 | https://en.wikipedia.org/wiki/RFpro | rFpro, originally rFactor Pro, is a driving simulation software used by racing teams and car manufacturers for advanced driver-assistance systems, self-driving cars and vehicle dynamics. rFactor Pro was created in 2007 as a project of a F1 racing team, using Image Space Incorporated's rFactor as a codebase. It has since been used by more F1 racing teams, top road car OEMs, Tier 1 suppliers, and motorsport manufacturers. It was originally developed for driver-in-the-Loop simulations, but has since been used for autonomous vehicle training as well. It is not licensed to consumers.
History
rFactor Pro was created in 2007 as a project of a F1 team, using the rFactor simulator as a codebase, and has since been used by more F1 racing teams, including Force India in 2009, Ferrari in 2014 and Alfa Romeo in 2019.
rFpro is developed by rFpro Limited, based in Wiltshire, UK. In 2017 rFpro acquired Image Space Incorporated's ISIMotor gaming engine, including the gMotor graphics engine, which it had been licensing since 2007. In 2019 rFpro was acquired by AB Dynamics.
In 2020 rFpro partnered with cosin scientific software to enable FTire (Flexible Ring Tire Model) to run with rFpro.
Features
rFpro features a 120 Hz graphics engine, a library of high definition laser scanned tracks and roads, and an infrastructure in which users can plug their in-house vehicle physics through a Simulink or a C/C++ interface. Alternatively rFpro rigid multibody physics engine can be used, which samples suspension and drive-train at 800 Hz. rFpro includes a tool called TerrainServer, which can feed the LiDAR data with a 1 cm resolution to a vehicle model running in realtime up to 5 kHz. The library of laser scanned tracks includes most of those used in the F1 championship.
In switching to rFpro for its simulator software in 2014, the Ferrari F1 team cited the high fidelity of the reproduced track surface, with an accuracy better than 1mm in Z (height) and 1 cm in X and Y (position), which represented a ten-fold improvement over their previous solution. They also cited the ability to respond to dynamic inputs faster than the driver can detect.
See also
Modelica
Powertrain
rFactor 2
References
Further reading
Nair, V. G., & Wishart, J. (2018) A study of driving simulation platforms for automated vehicles CAV Final Report, Arizona State University.
Rachel Evans Quantum leaps, Automotive Testing Technology International, September 2015
External links
https://www.rfpro.com
https://twitter.com/rfpronews
Automotive software
Driving simulators
Racing simulators
Simulation software
Industrial software | RFpro | [
"Technology"
] | 561 | [
"Industrial software",
"Driving simulators",
"Industrial computing",
"Real-time simulation"
] |
69,327,679 | https://en.wikipedia.org/wiki/Weather%20of%202022 | The following is a list of weather events that occurred on Earth in the year 2022. The year began with a La Niña. There were several natural disasters around the world from various types of weather, including blizzards, cold waves, droughts, heat waves, wildfires, floods, tornadoes, and tropical cyclones. The deadliest weather event of the year were the European heat waves, which killed over 26,000 people, 11,000 of which were in France. The costliest weather event of the year was Hurricane Ian, which caused at least $112.9 billion in damages in Florida and Cuba. Another significant weather event was the Pakistan floods, which killed 1,739 people and a total of $14.9 billion in damages.
Deadliest events
Types
Cold snaps and winter storms
On January 8, a snowstorm in Pakistan caused 23 deaths.
Three significant winter storms affected North America two at the beginning of the year, one in the middle of January that killed five and one in early February that killed eight, and the other at the end of year in December of 2022 that killed at least 50.
Southern Ontario saw the second snowiest day during the January storm, with schools and airports shutting down. The storm also spawned a brief EF2 tornado, causing several injuries and significant damage in Iona, Florida.
of snow fell near Colorado Springs, Colorado during the February winter storm, which also produced several tornadoes, one of which caused a death. As the storm passed, the temperature dropped dramatically in places such as New York City.
Less significant events also occurred throughout the winter. On January 3–4, a winter storm caused five deaths, and a 24 hour-long-traffic jam on Interstate 95 in Virginia. On January 22, Canaan, West Virginia set a new all-time record low. The cold wave behind it results in five deaths. On January 21, a winter storm killed one person in North Carolina when an ambulance slid off the road. A late January blizzard dumps massive snowfall, especially over Boston, and results in four deaths on Long Island. In late February, a winter storm kills two people: one each in Tennessee and Kentucky. On March 28, during a record breaking cold snap, a snow squall on Interstate 81 in Pennsylvania causes six deaths. Another blizzard occurred in mid April, causing one death in North Dakota.
Heat waves and droughts
Temperatures reached record-breaking highs when they were reported at in Onslow, Western Australia, in Phoenix, Arizona, in Sacramento. China experienced the worst heat wave in world history during the summer of 2022. Heat waves in India and Pakistan in the spring caused 90 deaths. North America also had significant heat waves, which caused 19 deaths in July alone. Both July and August saw the warmest daily minimums on record in the United States. The heat wave in California in September nearly broke the power grid. In Japan, June saw record-breaking temperatures, with the 40 °C (104 °F) threshold beating the previous record set in 2011. Heat waves in Europe cause 11,000 deaths in France alone. In Antarctica, rain fell on part of the continent, and one province set a monthly record high of .
Summer in the United States featured a long-lasting heat wave, which led to 117 deaths and $9.3 billion in damage. October 2022 was the hottest on record for Washington State.
Tornadoes
During 2022, 28 tornadoes were rated F3/EF3 or higher, with four of those receiving a rating of EF4; twenty EF3 tornadoes and four EF4 tornadoes occurred in the United States, two EF3 tornadoes occurred in China, one F3 occurred in Ukraine and one F3/EF3/T6 occurred in France and Belgium. The strongest tornado of 2022 impacted Pembroke and Black Creek in Georgia at EF4 intensity, with winds estimated at .
Worldwide, 33 tornado-related deaths have been confirmed: 24 in the United States, three in China, two each in Poland and Russia, and one each in the Netherlands and Ukraine.
The first tornadic fatality of the year occurred on February 3, when an EF2 tornado struck Sawyerville, Alabama, killing one person. A tornado outbreak occurred in Poland with at least 11 tornadoes on February 17, resulting in 2 fatalities and 5 injuries. 6 of the 11 tornadoes have been rated F2.
March saw a record number of tornadoes and 3 major outbreaks: 5-7, 21-23, and 29-31. The first tornado outbreak, despite being the smallest, is the deadliest tornado outbreak of 2022, causing 7 deaths of which six were in a low-end EF4 tornado that also caused 5 injuries and $220 million. The next tornado outbreak caused 3 deaths, plus 3 due to flash flooding in Alabama and one indirect death due to the 2022 New Orleans tornado. This EF3 tornado causes direct and indirect death, at least two injuries, and $32.5 million in damage, as well as 16,000 power outages. The final tornado outbreak is the largest, causing 90 tornadoes. It also causes 3 fatalities. An EF3 tornado in Florida early on March 31 caused two fatalities. Total damage from the storm reached $1.3 billion.
In April, tornadic activity died down a bit, but still featured a tornado outbreak of 87 tornadoes early in the month. That outbreak caused a tornadic death due to an EF4 tornado in Georgia. A storm complex in mid-April also results in a large tornado outbreak, but without fatalities. An EF3 tornado in Texas caused 23 injuries and $100,000 in damage. On April 29, an EF3 tornado near Andover, Kansas caused $41.5 million.
Tornadic activity slowed significantly after April. However, a significant tornado outbreak did occur across the US and Canada in mid to late May. This included an EF3 tornado in Gaylord, Michigan that caused 2 deaths, 44 injuries and $50.175 million in damage. The storm also helps fuel the May 2022 Canadian derecho that causes 11 deaths. A day before, a European tornado outbreak spawns 9 tornadoes that result in 46 injuries. After that, the next significant outbreak isn't for two months, until July 20. A tornado outbreak in China caused 3 deaths and 26 injuries.
Tropical and subtropical cyclones
On January 5, a tropical disturbance which was designated as 03F formed and was named Cyclone Cody, making it the first system of 2022. Cyclone Tiffany, the second named system of 2022, formed in the Australian region on January 9 and a tropical low designated as 11U formed on January 13, as a second system. On January 20, Tropical Storm Ana formed, which caused 142 deaths and $25 million across Madagascar, Malawi and Mozambique due to heavy rainfall and flooding. In the first week of February, Cyclone Batsirai exaggerated Ana's impacts, causing an additional 123 deaths and $190 million in damage. On February 14, Tropical Storm Dumako causes 14 more deaths in Madagascar, On February 23, Cyclone Emnati caused 15 more deaths in Madagascar. In March, Cyclone Gombe causes 72 deaths, with 63 in Mozambique, 7 in Malawi, and two in Madagascar. In the South Pacific in early February, Cyclone Dovi caused over $80 million in damages and 1 death across New Caledonia, Vanuatu, Norfolk Island, and New Zealand. In April, Tropical Storm Megi caused severe flooding that resulted in 214 deaths with 132 still missing. At the same time, Typhoon Malakas became a category 4-equivalent typhoon out to sea.
Extratropical cyclones and European windstorms
On January 10, the Hellenic National Meteorological Service named Storm Diomedes, making it the first European Windstorm of the year. The storm killed 1 person, and 1 person remains missing. 11 days later, on January 21, Storm Elpis formed, 3 people were killed and 18 injured after thousands were trapped by a snowstorm in Turkey. On January 28–30, Storm Malik hit Europe, killing 6 People. 2 people died in the United Kingdom, and 1 person died in Denmark, Germany, Poland and the Czech Republic. Over 29 people were killed across Europe when European Windstorms Dudley and Eunice made landfall on February 16–17 (Dudley) and February 18 (Eunice).
Wildfires
The first deadly wildfire of the year was the Boulder County fires, which started in 2021 and finished on January 1, 2022.
Following the Russian invasion of Ukraine, around 10,000 hectares of forest fires are currently burning near the Chernobyl Exclusion Zone, releasing radioactive air.
During the year, wildfires have caused at least $260,849,000 (2022 USD) in damage in the United States.
Timeline
This is a timeline of weather events during 2022.
January
In January 2022, the National Oceanic and Atmospheric Administration documented 13 weather-related fatalities and 18 weather-related injuries in the United States and Territories of the United States.
December 16, 2021 – January 19, 2022 – Floods in Malaysia, locally called Banjir Shah Alam, caused by Tropical Depression 29W, killed 54 people with two missing and caused over $4.77 billion (2021 USD).
December 24, 2021 – January 6, 2022 – Tropical Cyclone Seth killed two people and caused severe flooding in southeastern Queensland.
December 30, 2021 – January 1, 2022 – Grass fires in Boulder County, Colorado killed one person, left one person missing and injured six others. Wind gusts of were reported and the fire destroyed 1,084 structures and caused $513 million (2022 USD) in damage.
December 31, 2021 – January 6, 2022 – Floods in Oman killed at least six people.
January 1–4 – A winter storm, unofficially named Winter Storm Frida by The Weather Channel, killed five people, caused 428,000 power outages, and caused damage across the United States and Iceland.
January 1–27 – Severe storms and floods in Rwanda killed 15 people and injured 37 others. Seven of the fatalities and 26 of the injuries occurred due to lightning.
January 3 – A landslide in China killed four people, injured three others, and left nine missing.
January 4 – Floods in Indonesia killed nine people.
January 5–13 – Cyclone Cody killed one person and caused over $25 million (2022 USD) in damage across Fiji.
January 5 - Freezing rain leads to traffic accidents in the New York Metropolitan Area, causing two deaths and causing several delays, as well as closing New York State Route 25A.
January 7–8 – A blizzard in Murree, Pakistan killed 23 people.
January 8 – A rock collapse in Capitólio, Minas Gerais, Brazil, caused by heavy rains, killed ten people and injured 32 others.
January 10 – Floods in East London, South Africa killed 14 people and left hundreds homeless.
January 10–14 – European Windstorm Diomedes killed one person, with one missing, and caused damage across Greece.
January 11 – A 37-year-old man was injured by a lightning strike in Greece.
January 13–19 – A major winter storm, unofficially named Winter Storm Izzy by The Weather Channel, killed five people, injured 17 others, caused over 375,000 power outages, and caused damage across Canada and the United States.
January 16 – The storm system produced six tornadoes in Florida, including an EF2 tornado that caused major damage to three mobile home parks near Fort Myers and injured three people.
January 17 – Ottawa, Canada, recorded 48 centimetres (19 in) of snow, which is the second-largest snowstorm on record for Ottawa.
January 17 – Toronto, Canada, recorded 33 cm of snow, which is the third largest snowfall for Toronto since 1937. The storm prompted the Meteorological Service of Canada to issue the first blizzard warning for Toronto since 1978.
January 14 – Onslow, Western Australia recorded a temperature of , which if verified, would be tied as the highest in the Southern Hemisphere.
January 18 – Floods in Antananarivo, Madagascar, killed 11 people and left 500 people homeless.
January 19 – An avalanche in Slovakia killed one person and injured one other.
January 19–22 – A winter storm, unofficially named Winter Storm Jasper by The Weather Channel, killed one person, injured two others, and caused damage across the United States.
January 20–29 – Five people die in a cold wave across North America. Four people die of hypothermia near Emerson, Manitoba, Canada. Meanwhile, a fifth person dies in Upstate New York.
January 20 – René Robert, a Swiss photographer, died from hypothermia in Paris.
January 20 – A series of ice accumulation resulted in 23 injuries in Germany.
January 20–23 – Heavy rains in Pakistan killed eight people from multiple landslides and building collapses.
January 20–25 – Tropical Storm Ana killed 142 people and caused over $25 million (2022 USD) in damage across Madagascar, Mozambique, Malawi, South Africa, and Zimbabwe.
January 21 – An avalanche in Switzerland killed one person.
January 21–27 – European Windstorm Elpis becomes a rare snowstorm that killed three people and injured 18 others while affecting Greece, Cyprus, Israel, and Turkey. The storm also spawned a rare landspout which later became a snownado.
January 24 – A series of flash floods in Uganda killed nine people.
January 24 – February 11 – Cyclone Batsirai killed 123 people, injured at least ten others, caused 43,500 power outages and caused at least $190 million (2022 USD) in damage across Madagascar, Mauritius and Réunion.
January 26 – A landslide in Colombia killed two people.
January 27 – An avalanche in Turkey killed two people.
January 27–30 – A nor’easter and blizzard, unofficially named Winter Storm Kenan by The Weather Channel and Blizzard of 2022 by NBC News Boston, killed four people (2 direct and 2 indirect) and caused over 118,000 power outages across the East Coast of the United States.
January 29 – Providence, Rhode Island set a new all-time daily snowfall record of , breaking the previous record of from February 4, 1961.
January 29 – Boston, Massachusetts, recorded its snowiest day in January on record, and also tied its all-time daily snowfall record set on 17 February 2003, with of snow falling.
January 28 – A person dies from a cold weather-related incident in New York.
January 28–30 – European Windstorm Malik, also known as Storm Valtteri and Storm Nadia, killed six people, caused 810,000 power outages and caused damage across the United Kingdom, Ireland, Denmark, Norway, Sweden, Finland, Latvia, Estonia, Germany, Poland, and the Czech Republic.
January 28 – February 3 – Floods and landslides in Brazil killed 28 people.
January 29 – Two avalanches in the Polish side of the Tatra Mountains killed two people.
January 31 – The World Meteorological Organization certified a 477.2-mile-long lightning strike, also dubbed "megaflash", over the southern United States on April 29, 2020, as a new world record for the longest-lightning strike.
January 31 – The World Meteorological Organization certified a 17.1-second-long lightning strike over Uruguay and northern Argentina on June 18, 2020, as a new world record for the longest lasting lightning strike.
January 31 – February 1 – A landslide and floods in Ecuador killed 24 people with nine missing, and injured 47 others.
January 31 – February 1 – Floods in Haiti killed five people with one missing.
February
In February 2022, the National Oceanic and Atmospheric Administration documented 19 weather-related fatalities and 28 weather-related injuries in the United States and Territories of the United States.
February 1 – A landslide in Mozambique killed five people and injured two others.
February 1–9 – A winter storm and ice storm, unofficially named Winter Storm Landon and Groundhog Snowstorm, killed eight people (7 winter storms and 1 tornadic), caused over 375,000 power outages, and caused damage across the Central and Midwestern United States and Northern Mexico. Multiple states declared a state of emergency in preparation for the winter storm.
February 3 – The storm system also produced five tornadoes including three EF2 tornadoes. The second EF2 tornado, which prompted the National Weather Service to issue a particularly dangerous situation tornado warning, killed one person and caused damage in Sawyerville, Alabama.
February 3 – Wichita Falls, Texas recorded a new daily record snowfall of 1.0 inches, breaking the previous daily snowfall record from 1956.
February 2 – A power cable collapse in the Democratic Republic of the Congo killed at least 26 people. The cause is unknown, but lightning is the suspected cause.
February 2 – Twelve people died from hypothermia in Turkey, during a cold wave.
February 3 – A geomagnetic storm impacted the areas around the Arctic Ocean and disrupted up to 40 new SpaceX Starlink satellites that were launched earlier in the day. The storm also caused the Space Weather Prediction Center (SWPC) to issue a G1 geomagnetic storm warning.
February 4 – A series of avalanches killed eight people in Austria.
February 5 – An avalanche killed one person and injured four others in Austria.
February 5 – An avalanche killed one person in Italy.
February 7 – An avalanche killed two people in France.
February 7 – An avalanche killed 19 people in Afghanistan.
February 7 – A landslide in the Democratic Republic of the Congo killed three people and injured one other.
February 8 – A landslide in Colombia killed 14 people.
February 8–13 – Multiple cities in central and southern California, including San Francisco, Sacramento, Los Angeles, and San Diego experienced a record-breaking heat wave. San Francisco recorded 78 °F on February 10, an all-time record for the city for meteorological winter.
February 10–18 – Tropical Storm Dumako killed 14 people and caused over $1 million (2022 USD) in damage across Madagascar.
February 13–14 – A series of floods in Oman killed one person.
February 13–15 – A series of floods in Indonesia killed one person and affected over 10,000 people.
February 14–19 – European Windstorm Dudley killed nine people (7 extratropical cyclonic + 2 tornadic), injured five others, caused 225,000 power outages, and caused damage across Europe. Storm Dudley also spawned a tornado outbreak consisting of 24 tornadoes, with 23 in Poland and Germany and one in Italy. One of the tornadoes in Poland killed two people.
February 14–19 – European Windstorm Eunice, also known as Storm Zeynep in Germany and Storm Nora in Denmark, killed 17 people, caused over 2.4 million power outages, and caused over €1.3 billion (2021 EUR) in damage across Belgium, Denmark, France, Germany, Ireland, Lithuania, the Netherlands, Poland, and the United Kingdom.
February 15 – Harsh weather over the Atlantic Ocean killed 21 people, with 11 missing, after capsizing a Spanish fishing boat.
February 15 – A series of floods in Rio de Janeiro killed at least 231 people with five missing.
February 15–26 – Cyclone Emnati killed 15 people and caused over $1 million (2022 USD) in damage across Madagascar, Mauritius and Réunion.
February 18 – Floods in South Africa killed one person.
February 20–22 – European Windstorm Franklin killed two people and caused damage across the United Kingdom, Ireland, France, and the Netherlands.
February 20–22 – A winter storm in Japan killed one person and injured eight others.
February 20–24 – A series of floods and landslides in Bolivia killed 35 people and left 25 missing.
February 22 – Heavy rain caused mass floods that killed many people and hundreds of homes in Bukavu, Democratic Republic of the Congo.
February 22 – A winter storm in Minnesota, United States, killed one person.
February 23 – A landslide in Colombia killed three people and injured four others.
February 23- April 7 – A series of major floods in South East Queensland, and Northern Rivers, New South Wales in Australia killed 22 people and caused over $2.2 Billion in Damages to infrastructure and homes in the state of Queensland alone. Brisbane city recorded a record 678.8mm of rain over three days. This became the most expensive natural disaster in Australian history, with $3.5 billion worth of claims paid out by insurers.
February 24 – A winter storm in the Southeastern United States killed seven people.
February 27 – A landslide in Colombia killed one person.
March
In March 2022, the National Oceanic and Atmospheric Administration documented 39 weather-related fatalities and 110 weather-related injuries in the United States and Territories of the United States.
March - April 29 - A heat wave affects India and Pakistan. Temperatures exceed more than and at least 90 people have died.
March 2 – A series of floods in Indonesia killed two people.
March 5–7 – A tornado outbreak across the Midwestern United States killed seven people from 29 tornadoes, including a low-end EF4 tornado with winds of near Winterset, Iowa that traveled nearly 70 miles, with the National Weather Service issuing multiple particularly dangerous situation (PDS) tornado warnings. Damage totaled up to $1 billion.
March 5–17 – Cyclone Gombe killed 72 people, with one missing, and caused over $95 million (2022 USD) in damage across Madagascar, Mozambique, and Malawi.
March 13–14 – A G2 geomagnetic storm impacted the areas around the Arctic Ocean.
March 17 – Dense fog on I-57 in Missouri causes a chain reaction of crashes that killed six people.
March 21–23 – A tornado outbreak and flash flooding event in the Southern and Eastern United States killed five people, two tornadic and 3 non-tornadic, and caused $47.7 million in damage. Roughly 75 tornadoes were confirmed, including an EF3 tornado that hit the eastern part of the New Orleans metropolitan area and numerous tornadoes across Texas and Mississippi.
March 28 - A late-season cold snap sets record-low temperatures in the Northern United States. It also triggers a snow squall along Interstate 81, in Schuylkill County, Pennsylvania in killing 6.
March 29–31 – A tornado outbreak across the Southern United States produces many high wind warnings, as well as many tornado warnings. The tornado outbreak caused 3 deaths and $1.3 billion in damage.
March 29–31 – Tropical Depression 01W killed 6 people and caused damage across Vietnam.
April
In April 2022, the National Oceanic and Atmospheric Administration documented 20 weather-related fatalities and 72 weather-related injuries in the United States and Territories of the United States.
April 4–7 – A large tornado outbreak in the Southeastern United States produced 89 tornadoes, high winds, tornado warnings, one tornado emergency, and three deaths (one tornadic from an EF4 tornado in Black Creek, Georgia and two non-tornadic). Damage accumulated to $1.3 billion.
April 6 - McAllen, Texas soared to , their warmest ever April temperature and 3rd warmest temperature for any month.
April 8–13 – Tropical Storm Megi killed 214 people, with 132 missing and caused over $90.8 million (2022 USD) in damage across Philippines.
April 8–21 – Severe floods killed 435 people and caused over $1.57 billion (2022 USD) in damage across South Africa.
April 11–14 - A storm complex caused 2 non tornadic fatalities, 28 tornadic injuries and $2.2 billion in damage.
April 12 – May 7 - The McBride Fire burns across New Mexico, killing two.
April 18–19 - A nor’easter in the Northeastern United States kills one person.
April 29 - During a tornado outbreak, after a storm chase of the EF3 tornado in Andover, Kansas, 3 storm chasers die when their car skids off the road due to hydroplaning and an oncoming vehicle crushes them.
May
In May 2022, the National Oceanic and Atmospheric Administration documented 26 weather-related fatalities and 110 weather-related injuries in the United States and Territories of the United States.
2022 Iraq dust storms
May 12 – A derecho in the Midwestern United States caused 5 deaths, 13 injuries and $1.3 billion in damage.
May 14 – September 7 - Heat waves in North America kill 117 people and cause $9.3 billion in damage.
May 20 - A severe weather and tornado outbreak causes one death and 60 injuries. Eight tornados, of which three were F2 and five F1 touched down. The cities of Lippstadt and Paderborn were struck by F2 tornadoes each.
May 20 – An EF3 tornado in Gaylord, Michigan causes 2 deaths and 44 injuries.
May 21 – A powerful derecho (thunderstorm and windstorm) struck a swath of Southern Ontario and western Quebec killing 10 people in Ontario and 1 Quebecer who was boating on the Ottawa River. Most of the Ontario deaths were the result of falling trees, including single fatalities in Greater Madawaska, Ottawa, Brampton, North Kawartha, Port Hope, Ganaraska Forest in Clarington, Kitchener and Peterborough with one person killed when a tree hit a trailer at Pinehurst Lake Conservation Area south of Cambridge. Winds of 132 km/h were recorded in Kitchener, while winds of 120 km/h were recorded in both Toronto and Ottawa. By Saturday evening, over 500,000 residences in Ontario and 460,000 residences in Quebec were without power due to wind and rain causing numerous trees and electricity poles to fall down. Many buildings, cars, electricity polls and hydro transmission towers across Southern Ontario (including over 800 electricity polls and four hydro transmission towers) and in parts of Quebec were damaged by falling trees and branches or by the fierce winds alone.
May 22 – Heavy rains have caused widespread flooding in northeastern parts of Bangladesh and in the state of Assam, India, leaving millions stranded and 41 dead.
May 28–31 – Hurricane Agatha became the strongest hurricane to make landfall along the Pacific coast of Mexico in the month of May since records began in 1949. On the afternoon of May 30, the hurricane made landfall just west of Puerto Ángel, Oaxaca, with winds of 105 mph (165 km/h). Agatha weakened rapidly as it moved inland, and soon dissipated. Heavy rain brought by the storm triggered landslides and flash flooding, killing at least 9 and leaving 6 missing in Oaxaca.
June
In June 2022, the National Oceanic and Atmospheric Administration documented 101 weather-related fatalities and 60 weather-related injuries in the United States and Territories of the United States.
June 2–6 – Potential Tropical Cyclone One, which later became Tropical Storm Alex, strikes Cuba and Florida, killing 4 and dumping over a foot of rain. The storm caused at least $104,000 in damage.
June 10 – The 2022 Montana floods kill one and cause $29 million, and shut down Yellowstone National Park.
June 13–14 – The 2022 Great Lakes Derecho causes severe damage in parts of Indiana and Ohio, particularly in Fort Wayne and Holmes County, leaving more than 400,000 households in the Midwest without power. The derecho produced wind gusts of 70 to 80 mph, and a gust of 98 mph was recorded at Fort Wayne International Airport, breaking the previous record of 91 mph. A heat wave followed, worsening conditions for those without power. Many towns and villages were inaccessible until clean-up work could begin, as a result of fallen trees, power lines and other debris. Much of the damage in Ohio has been attributed to a macroburst. Three confirmed EF1 tornadoes touched down in Ohio, and at least one death occurred as a result of this storm in Indiana.
June 14–Present — A series of flash floods in Pakistan killed over 1,100 people.
June 19 – A man died due to hypothermia in Maine.
June 27 – Japan saw the worst heatwave in 150 years.
July
In July 2022, the National Oceanic and Atmospheric Administration documented 108 weather-related fatalities and 147 weather-related injuries in the United States and Territories of the United States.
July 3 – The 2022 Marmolada serac collapse, fueled by the European heatwave, kills 11 people and injures 8.
July 3–8 Major flooding occurred in New South Wales, Australia. One person was killed and 85,000 were displaced.
July 4 – Tropical Storm Colin performs a brown ocean effect by forming inland on South Carolina and killed one man, cancelling July 4 events.
July 11 – The city of Paysandú, Uruguay was hit with a squall line with winds of up to 160 km/h. Trees were uprooted, and more than 30,000 residents suffered power outages. A newspaper building, costing about 1.2 million US dollars, was lost, along with several radio antennas. Around a thousand roofs were severely damaged or blown off.
July 15 – High winds causing a dust storm on Interstate 90 in Montana lead to a car crash killing 6.
July 20 – Heat records tumbled and firefighters faced new blazes as much of Western Europe baked in a gruelling heatwave.
July 21 – China endures summer of extreme weather as record rainfall and scorching heat wave cause havoc.
July 21 - A girl dies due to a falling tree in a severe thunderstorm in Maine.
July 24–26 – Severe floods began in Missouri on July 24, culminating during July 25 and 26, when St. Louis broke its previous 1915 record for the most rainfall in a span of 24 hours. Governor Mike Parson declared a state of emergency on July 26. Over one hundred people were rescued from floods, and two people were killed.
July 26 or 27 – A 7-year-old girl dies due to a falling tree in Great Smoky Mountains National Park, possibly due to flooding in the area throughout July.
July 27–28 – Historic flooding occurred in Kentucky, with the Governor of Kentucky, Andy Beshear, declaring a state of emergency saying “We are currently experiencing one of the worst, most devastating flooding events in Kentucky's history.” More than 700 homes were flooded as a result of rainfall 600 percent more than normal. On July 29, President Joe Biden declared that a major disaster existed in Kentucky and ordered federal aid to supplement state and local recovery efforts in the areas affected by severe storms, flooding, landslides, and mudslides. At least 37 people have been killed with multiple others still missing.
August
In August 2022, the National Oceanic and Atmospheric Administration documented 36 weather-related fatalities and 36 weather-related injuries in the United States and Territories of the United States.
August 1 – Floods and landslides in the Bugisu and Sebei sub-regions of Eastern Region, Uganda kill at least 10 people.
August 4 - A lightning strike outside the White House kills three people and injures another.
August 5 - Flash floods in Death Valley National Park resulted in more than 1,000 visitors and park staff stranded. The of rain there was a record for August.
August 7 - Flash flooding around Seoul, South Korea killed 9 people. Some areas of Seoul received rainfall that hadn't been seen in 80 years.
August 9 - A thunderstorm knocks down a tree in Georgia, killing 2 people and injuring 3 others.
2022 European drought
August 28 – September 6 - Typhoon Hinnamnor, known in the Philippines as Super Typhoon Henry, kills 12 with 1 missing, and causes $1.21 billion in damage around Taiwan, Philippines, South Korea, Japan, and North Korea.
August 29 - Three people die in severe storms in the Midwest. Over 700,000 customers in Michigan lose power. Winds gusted up to .
August 31 - A hailstorm in Spain resulted in one death and 50 injuries.
September
In September 2022, the National Centers for Environmental Information (NCEI) documented 38 weather-related fatalities and 40 weather-related injuries in the United States and Territories of the United States. However, the National Hurricane Center recorded over 150 fatalities during the month from Hurricane Ian, indicating errors in the NCEI fatality totals for the month.
September 1 – A temperature of is recorded in Furnace Creek, California, United States, breaking the record for the highest September temperature ever recorded in the world.
September 3 – Deadly flash flooding in Indiana kills one person.
September 4 – During Hurricane Earl, a lightning strike kills two in Puerto Rico.
September 4–10 – Hurricane Kay kills 3 people in Mexico.
September 5–present – The Fairview Fire burns across California, killing two.
September 13 — A gustnado impacts a seven mile path in Arizona. In December 2022, the National Centers for Environmental Information published its entry into the Storm Event Database. In that entry, they marked it as an EF0 tornado, stating, “A tornado formed and traveled along the leading edge of a thunderstorm outflow boundary (gustnado)”. This marks the first ever gustnado to receive a rating on the Enhanced Fujita scale.
September 14–25 - Hurricane Fiona kills 31 people in Guadeloupe, Puerto Rico, and Canada.
September 17–18 – Flooding in Western Alaska as a result of the passage of Extratropical Cyclone Merbok through the Aleutian Islands into the Bering Sea. Governor Mike Dunleavy declared a state of emergency in the region before the cyclone hit. The barometric pressure at the storm's center reached a low of as it approached the Aleutian Islands. Dangerous storm surge inundated several coastal villages and towns. Water levels in Unalakleet peaked at around , which was among its largest peaks on record. Significant flooding and gale force winds were also reported in Golovin, Nome, Shaktoolik and Kotlik. Despite the widespread coastal flooding no injuries were reported.
September 21–30 - Typhoon Noru, known in the Philippines as Super Typhoon Karding, kills 40 and causes damage across Philippines and Vietnam.
September 23 – October 2 - Hurricane Ian kills 157 people across Cuba, Florida, and North Carolina, and Virginia.
October
In October 2022, the National Centers for Environmental Information documented 3 weather-related fatalities and 7 weather-related injuries in the United States and Territories of the United States.
October 7–10 — Hurricane Julia kills 91 and causes damage across Trinidad and Tobago, Venezuela, Colombia, Nicaragua, El Salvador, Honduras, Guatemala, Panama and Mexico.
October 9–22 – An extratropical cyclone in the Bellingshausen Sea that formed near Tonga becomes the most intense extratropical cyclone on record. Analysis by the European Centre for Medium-Range Weather Forecasts (ECMWF) using ERA5 reanalysis data estimated the pressure of the cyclone as early on 17 October while a paper published in Geophysical Research Letters in July 2023 got a minimum pressure of the same day.
October 13—Present — South eastern Australia floods kills 1 in Rochester, Victoria. Towns across Victoria, Tasmania and New South Wales were evacuated, thousands of properties have been damaged. About 100 properties in inner suburbs of Melbourne along the Maribyrnong river were flooded.
October 16 — Seattle sets breaks a daily heat record for the day by 16 °F (9 °C), and with a temperature of , is only one degree shy of tying the monthly record high.
October 19 — Fog on Interstate 5 in Oregon results in a car crash, killing one person.
October 26 – November 3 — Tropical Storm Nalgae, known in the Philippines as Severe Tropical Storm Paeng has killed 164 and caused $237 million in damages.
October 28 - Burlington, Vermont recorded its first freeze, which became the latest first freeze since the National Weather Service recorded temperatures at Burlington International Airport, and latest since 1920 in general, when temperatures were recorded closer to the lake.
November
In November 2022, the National Centers for Environmental Information documented 18 weather-related fatalities and 396 weather-related injuries in the United States and Territories of the United States.
November 4–5 - An intense tornado outbreak occurred in the Ark-La-Tex region of the United States. An EF4 tornado struck Caviness, Texas, destroying multiple structures before later moving into Oklahoma and dissipating. Another EF4 tornado struck areas near Clarksville, Texas before also tracking into Oklahoma and inflicting severe EF3 damage in Idabel. Numerous other tornadoes also touched down, including an EF2 tornado that killed one in Pickens, Oklahoma, an EF3 tornado that killed one person northwest of Daingerfield, Texas, and another EF3 tornado that struck Simms and New Boston, Texas. In all, 31 tornadoes were confirmed, with 2 tornadic deaths, 1 non-tornadic death, and at least 24 injuries.
November 6–7 - A record breaking November heat waves shatters records across the Eastern United States. Burlington, Vermont reached , the latest so late in the year. Atlanta hit , which tied for the hottest temperature so late in the year. Harlingen, Texas hit which also tied for the hottest so late in the year. Washington DC and Baltimore had lows of and , the warmest so late in the year. Portland, Maine set a record for warmest November low, at , after a monthly record high of . On November 7, it was so warm several places set monthly high temperature records, including Islip at , and New Orleans at .
November 7–12 - Hurricane Nicole kills 11 people across the Dominican Republic and the United States.
November 17–19 - November 2022 Great Lakes winter storm
November 18 - The earliest trace of snow occurred in Dallas.
November 18—20 - 2022 Philippine floods - An intertropical convergence zone and a low pressure area caused floods and rain in the Philippines, killing 5.
November 20 - A flood in Albania killed two people and caused damage to infrastructure and buildings.
November 22 - A woman was killed due to hypothermia in Zion National Park, while her husband was rescued. Water temperatures in the Virgin River, which they walked through, dropped to , according to the United States Geological Survey.
November 24 - Two people were killed due to torrential rainfall in Saudi Arabia. Over 6 hours, fell. This became the heaviest rainstorm on record for Jeddah.
November 29–30 - Another significant tornado outbreak hits the Southern United States. An EF3 tornado in Caldwell Parish, Louisiana causes damage to trees and mobile homes as it touches down along LA 126. An EF2 tornado strikes the Flatwood community north of Montgomery, Alabama, killing two people.
December
December 5 - Utqiagvik, Alaska set a record high for the month of December, at .
December 6–10 - Cyclone Mandous kills nine people across Tamil Nadu and Sri Lanka.
December 9–12 - Tropical Storm Pakhar, known in the Philippines as Tropical Storm Rosal, kills eight people in the province of Tanay, Rizal.
December 12–15 - Another devastating tornado outbreak hits the Southern United States. An EF3 tornado strikes the Union Village Apartments in Farmerville, Louisiana. The next day, an EF2 tornado strikes the New Orleans metro and damages some of the areas previously hit by another tornado earlier in the year.
December 21–26 — A powerful winter storm, unofficially named Winter Storm Elliott by The Weather Channel, kills at least 100 people, cuts power to over 7.7 million customers, disrupts travel, and sets many record-breaking low temperatures across the United States and Canada, with Casper, Wyoming setting an all-time record low at .
December 24–25 — A snowstorm in Japan kills 17 people.
December 27 - A storm spreads high winds across Oregon, leading to 5 fatalities from 3 crashes.
December 31 — Record rainfall sweeps throughout California, and the total rainfall accumulation in San Francisco reaches , which is the second largest single day total on record. The storms also caused 2 people to die throughout the region.
Space weather
February 4 – A mild solar particle and geomagnetic storm led to the failure and reentry of 40 SpaceX Starlink satellites that had been recently launched and were in low Earth orbit (LEO)
Events in meteorology
June 28 – A review elucidates the current state of climate change extreme event attribution science, concluding probabilities and of links as well as identifying potential ways for its improvement.
July 4 – Scientists report that heatwaves in western Europe are increasing "three-to-four times faster compared to the rest of over the past 42 years" and that can explain their increase.
July 18 – A study shows that climate change-related exceptional marine heatwaves in the Mediterranean Sea during 2015–2019 resulted in widespread mass sealife die-offs in five consecutive years.
August 12 — The National Centers for Environmental Information publish a report called Assessing the Global Climate in July 2022, where they state an all-time record cold temperature occurred in Australia during the month. On October 7, 2022, Zack Labe, a climate scientist for the NOAA Geophysical Fluid Dynamics Laboratory released a statement and a climate report from Berkeley Earth on the average monthly temperature, tweeting, “There are still no areas of record cold so far in 2022.” Labe's statement also denied the record cold temperatures in Brazil, reported by the National Institute of Meteorology in May 2022, a month before the official start of winter, was also not record cold temperatures.
See also
Weather of 2021
List of F4 and EF4 tornadoes (2020–present)
Notes
References
Weather by year
Weather-related lists
2022-related lists | Weather of 2022 | [
"Physics"
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69,328,431 | https://en.wikipedia.org/wiki/L%C3%BCbeck%20disaster | From 1929 to 1933, 251 infants in Lübeck, northern Germany, were given three doses of the oral BCG vaccine against tuberculosis, which was accidentally contaminated with the bacteria responsible for the disease. 173 later developed signs of the illness and 72 died.
Contaminated vaccine
This vaccine itself was initially blamed, until an inquiry headed by of the Robert Koch Institute and Ludwig Lange of the Ministry of Health identified contamination as the cause. The event later became known as the Lübeck disaster, or in German, the Lübecker Impfunglück (Lübeck vaccine disaster). Major scientific journals worldwide commented on the disaster and subsequent trials of the medical staff, such as The Lancet and the Journal of the American Medical Association.
Legal consequences
On 6 February 1932, , the head of the general hospital in Lübeck, was found guilty of negligent homicide and negligent bodily harm, and sentenced to two years in prison. Deycke negligently cultivated the BCG vaccine in a laboratory unsuitable for vaccine production and refrained from animal experiments. Ernst Altstaedt was sentenced to 15 months in prison for negligent homicide and negligent bodily harm as he did not test the vaccine in animal experiments and only insufficiently observed the children. The co-accused chairman of the Lübeck health department, Max Klotz, was acquitted, as was Deycke's laboratory assistant, Anna Schütze.
Subsequent developments
Despite the investigation's finding that contamination caused by laboratory error (not the BCG vaccine itself) was the cause of the deaths, the Lübeck disaster diminished public confidence in, and usage of, the BCG vaccine for a time.Elizabeth Whittaker & Surinder K. Tamne, "Bacillus Calmette-Guérin (BCG) Vaccine" in Tuberculosis in Clinical Practice (ed. Inn Min Kon: Springer, 2021), pp. 16-17. After the tragedy, the oral route of administration for BCG vaccine was discontinued. It was replaced by alternate, improved methods of administration for the BCG vaccine: intradermal (ID) (introduced 1927), multiple puncture (1939), and scarification (1947). The First International BCG Congress in Paris, held in 1948, concluded that the BCG vaccine was safe and effective.Kim Connelly Smith, Ian M. Orme & Jeffrey R. Starke, "Tuberculosis vaccines" in Vaccines (6th ed.), p. 727. Elsevier/Saunders: Eds. Paul A. Offit, Stanley A. Plotkin, Walter A. Orenstein (2013). With the BCG vaccine's safety and effectiveness established, and new methods of administration, confidence in the BCG vaccine was restored, and mass vaccination campaigns resumed globally. Compulsory BCG vaccination of infants was reinstated in East Germany in 1952.
References
External links
Health disasters in Germany
1930s health disasters
Vaccine controversies | Lübeck disaster | [
"Chemistry",
"Biology"
] | 599 | [
"Vaccination",
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67,913,561 | https://en.wikipedia.org/wiki/Organonickel%28IV%29%20complex | Organonickel(IV) complex are organonickel compounds that feature nickel in the +4 oxidation state. These high-valent nickel compounds are intermediates or models thereof for various catalytic reactions.
Representative preparation
Ni(IV) complexes are typically supported by highly basic and chelating ligands. They are often produced by oxidation of related Ni(II) and Ni(III) complexes using both conventional and exotic oxidants, such as ferrocenium and S-(trifluoromethyl)dibenzothiophenium triflate (Umemoto reagent). For example, one of the first isolated NiIV complexes that was used in a cross coupling transformation was reported by Linden and Dimitrov in 2003 and was prepared by simple air-induced oxidation of the following anionic NiII complex:
Reactivity and synthetic transformations
Carbon-heteroatom bond formation
Studies reported by Sanford and Camasso in 2015 revealed the ability of a NiIV organometallic complex to deliver carbon(sp3)-oxygen, carbon(sp3)-nitrogen, and carbon(sp3)-sulfur bonds. The NiIV species was generated by oxidation of a nickel(II) trispyrazolylborate complex.
C-H activation
In 2014, Chatani and coworkers proposed that a NiIV intermediate was formed during an aminoquinoline-directed aliphatic C-H activation process using diaryliodonium salts as an oxidant.
Trifluoromethylations
NiIV can perform challenging trifluoromethylation reactions on (hetero)arenes. A representative method is shown below, reported by Nebra and coworkers in 2017. Here, a six-coordinate NiIV complex transfers a CF3 ligand to a functionalized arene.
A catalytic variant was reported by Sanford and coworkers in 2019. The mechanism for this transformation is shown in the following scheme. Here, the key NiIV intermediate undergoes a slow homolysis to produce a NiIII intermediate and a trifluoromethyl radical, which can promote propagation of the catalytic cycle.
References
Organometallic compounds
Nickel compounds | Organonickel(IV) complex | [
"Chemistry"
] | 446 | [
"Organic compounds",
"Organometallic compounds",
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67,915,525 | https://en.wikipedia.org/wiki/Crystalline%20sponges | Crystalline sponges are series of organometallic networks developed by Japanese chemist Makoto Fujita. The organic small molecules are absorbed into the void space of the crystalline sponges. Since the organometallic network of crystalline sponges can interact with the small molecule substrates via non-covalent interactions, the absorption can be selective. That is, the crystalline sponge can enrich certain molecules from a mixture.
As the crystal sponges are highly organized frameworks, the structure of the whole host-guest complex can be characterized by X-ray diffraction. Because the absorbate is encapsulated in a pre-organized environment, no single crystal of the substrate is needed in the X-ray diffraction. Besides, the X-ray crystallography of liquid samples can also be conducted.
Molecular structure and composition
The first crystalline sponges developed by Makoto Fujita is [(Co(NCS)2)3(TPT)4], which is an infinitely extensive framework of Co2+ octahedral complex. Each octahedral complex is composed of six Co(NCS) vertexes and four 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPT) ligands. Besides the basic octahedral cavity (M6L4), there are also two different cuboctahedral cavities (M12L8 and M12L24) which can accommodate larger molecules, such as C60, C70.
In 2013, the Fujita and his team discovered that the [(ZnI2)3(TPT)2] organometallic network can also act as a crystalline sponge. Because Zn crystalline sponges are less symmetrical (C2) than Co crystalline sponges, the X-ray diffraction analysis of its guest molecules is easier to be elucidated.
The Zn-based sponges also have following advantages: (1) Pores sizes are suitable for accommodating general organic compounds (5 × 8Å), (2) The distribution of TPT ligand is flat, providing better stacking opportunity of aromatic guest compounds or C—H π interaction opportunity with aliphatic guest compounds, (3) The iodine atoms and the pyridinium protons can be hydrogen bond acceptors or donors, respectively. They would enhance the interaction between the substrate and the crystalline sponges, (4) The framework of Zn-based crystalline sponge is flexible to some extent. The molecule which is a little bit larger than the sponge cavity can still be accommodated via framework expansion to adjust the pore size.
Preparation
For preparation of [(Co(NCS)2)3(TPT)4] crystalline sponges, the methanol solution of Co(NCS)2 was added into the TPT solution in 1,2-dichlorobenzene/methanol. After 7 days, the [(Co(NCS)2)3(TPT)4] would form and can be isolated by filtration.
For preparation of [(ZnI2)3(TPT)2] crystalline sponges, the methanol solution of ZnI2 was added onto the top of TPT in nitrobenzene solution. After 7 days, the [(ZnI2)3(TPT)2] would form and can be isolated by filtration.
Once the feedstocks were mixed, crystalline sponges would be produced via self-assembling processes, forming the thermodynamically stable organized network structures.
Application
Extract compounds from mixture
The crystalline sponges can be viewed as the extension of organometallic cage compounds. They can not only accommodate guest molecules, but also provide non-covalent interactions with the guest. To exploit these properties, the Fujita group demonstrates [(Co(NCS)2)3(TPT)4] can enrich C70, C78, or other higher fullerenes from C60 mixtures as normal cage compounds did in precedent research.
X-ray crystallography of liquids encapsulated within the sponge framework
In 2013, the Fujita group rediscovered that the molecular structure of liquids can be elucidated by X-ray crystallography in the presence of [(ZnI2)3(TPT)2] crystalline sponges. The guest compounds, such as cyclohexanone, cinnamaldehyde were dropped onto the pre-made single crystal of crystalline sponges. The liquid samples would penetrate into the crystalline sponges, and occupy the sponges’ cavities. As crystalline sponges provide a well-organized structure, the guests in sponges’ cavities would also have organized distribution in the space. As a result, the structure of guest can be characterized by X-ray crystallography .
Some of the structures of liquid natural products which are difficult to differentiate by NMR spectroscopy can be easily characterized by crystalline sponges techniques. Elatenyne is a liquid molecule isolated from Laurencia elata, marine red algae. Due to its pseudo-C2 symmetry, the difference of NMR spectrum between elatenyne and its stereoisomer is hard to differentiate. However, with the crystalline sponges, the Fujita group easily elucidated the chirality in the elatenyne.
Cycloelatanene A and B are a pair of diastereomers isolated from Laurencia elata. Both compounds are liquid, so the traditional X-ray diffraction analysis cannot elucidate their absolute chirality. After the crystalline sponges assisted X-ray crystallography, the Fujita group revised the chirality of C4 position reported by precedent NMR analysis.
References
Organometallic compounds
Organometallic chemistry | Crystalline sponges | [
"Chemistry"
] | 1,209 | [
"Organic compounds",
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67,917,261 | https://en.wikipedia.org/wiki/Criticism%20of%20credit%20scoring%20systems%20in%20the%20United%20States | Credit scoring systems in the United States have garnered considerable criticism from various media outlets, consumer law organizations, government officials, debtors unions, and academics. Racial bias, discrimination against prospective employees, discrimination against medical and student debt holders, poor risk predictability, manipulation of credit scoring algorithms, inaccurate reports, and overall immorality are some of the concerns raised regarding the system. Danielle Citron and Frank Pasquale list three major flaws in the current credit-scoring system:
Disparate impacts: The algorithms systematize biases that have been measured externally and are known to impact disadvantaged groups such as racial minorities and women. Because the algorithms are proprietary, they cannot be tested for built-in human bias.
Arbitrary: Research shows that there is substantial variation in scoring based on audits. Responsible financial behavior can be penalized.
Opacity: credit score technology is not transparent so consumers are unable to know why their credit scores are affected.
The scoring system has also been critiqued as a form of classification to shape an individual's life-chances—a form of economic inequality. Since the 1980s, neoliberal economic policy has created an inverse correlation between the expansion of credit and a decline in social welfare—deregulation incentivizes financing for the consumption of goods and services that the welfare state would alternatively provide. Credit scoring systems are seen as scheme to classify individuals creditworthiness necessitated by the loss of these collective social services. The credit scoring system in the United States has been compared to, and was the inspiration for, the Social Credit System in China.
The use of credit information in connection with applying for various types of insurance or in landlord background checks (for rental applications) has drawn similar amounts of scrutiny and criticism, because obtaining and maintaining employment, housing, transport, and insurance are among the basic functions of meaningful participation in modern society.
Discriminatory effects
Credit scores are widely used as the basis for decisions to allow or deny individuals the opportunity to do things such as taking out loans, buy houses and cars, and open credit cards and other kinds of accounts. This has been criticized as a practice having discriminatory effects. Credit companies purport to measure creditworthiness by looking at information like: the number of accounts held, the age of associated credit accounts, consumer payment history of borrowed money, and the punctuality and consistency of payments.
As credit scores have become necessary to maintain credit and purchasing power, this system has been criticized as a wall between favored and disfavored classes of people. The expansion of accessible credit can come with a downside of exclusion as people with poor credit (those that are considered high risk by credit scoring systems) become dependent on short-term alternatives such as licensed money lenders (the home credit industry), pawn brokers, payday lenders, and even loan sharks. Credit scores can function as a form of social hierarchy that creates opportunities to exploit poor Americans. This can also prevent people from ever escaping their poverty or a poor financial past.
Credit scoring systems also act as a way to treat individuals as objects that are subject to a particular set of quantifiable attributes. In addition, they have a degrading potential that celebrates calculability over human needs. Discriminatory responses to poor credit create a self-fulfilling prophecy as it raises costs for future financing which increases the likelihood of being unemployed or insolvent. Since credit scores aim to classify people, other markets have expanded its applicability for use as a screening or assessment tool. Credit is no longer used just for financial products such as mortgage loans, but is increasingly being applied cross-institutionally for other services such as:
car insurance
health insurance
starting utilities (electricity, natural gas, water, etc.)
employment
rental housing
small purchase financing (e.g. cell phones, appliances, etc.)
Alternative credit scoring systems can use data such as rental payments, utility payments, subprime credit, and cell phone bills. Other sources are social media activities, internet browsing history, employment history, student history, past loan application dates and locations, or the method one uses when purchasing gasoline. Scores have also used for bespoke purposes such as dating. Prior to the formation of the Fair, Isaac and Company (FICO) or the Fair Credit Reporting Act of 1970), early credit scoring systems such as the Retail Credit Company (now Equifax) in Atlanta, Georgia gathered information on individuals' sexual lives, disabilities, their political ideologies, and social behaviors. Today, some scoring systems such as those developed by Versium Analytics are moving far beyond scores for financial products to measure probabilities that a consumer will commit fraud, cancel a subscription, be at risk of identity theft, buy environmentally friendly goods, donate to charity, among others.
Racism
Credit score systems are well known to contain racial bias and have been shown to increase racial disparities as studies show that African American and American Latino populations have substantially lower scores than the white American population on average. Racial discrimination also results in impacts on the credit scores and economic security of communities of color—that ultimately, "entrenches and reinforces inequality by dictating a consumer's access to future opportunities".
Numerous studies have found racial disparities in credit scoring:
1996 study found African-Americans were three times as likely to have FICO scores below 620 as whites and that Hispanics were twice as likely.
1997 study found Black, Indigenous, and people of color [BIPOC] neighborhood consumers had lower credit scores.
2004 study found high Black, Indigenous, and people of color [BIPOC] zip codes to have significantly worse scores than non-Black, Indigenous, and people of color [BIPOC] zip codes.
2004 study found that African American and Hispanic consumers constituted over 60% of the consumers having the worst credit scores.
2004 study found the median credit score for whites in 2001 was 738, but the median credit score for African Americans was 676 and for Hispanics was 670.
2004 research study found fewer than 40% of consumers who lived in high-Black Indigenous and people of color [BIPOC] neighborhoods had credit scores of over 701.
2006 studied US counties with high Black, Indigenous, and people of color [BIPOC] populations determining that those countries had lower average credit scores than predominantly white counties.
2007 study by the Federal Trade Commission found that African Americans and Hispanics strongly overrepresented in the lowest scoring categories regarding auto insurance company's use of credit scores.
2007 report found significant racial disparities in 300,000 credit files matched with Social Security records with African American scores being half that of white, non-Hispanics.
2010 study found that African American in Illinois zip codes had scores of less than 620 at a rate of 54.2%. In zip codes that were majority Latino, 31.4% of individuals had a credit score of less than 620, and only 47.3% had credit scores greater than 700.
2012 study examined the credit scores for about 200,000 consumers finding the median FICO score in majority minority zip codes was in the 34th percentile, while it was in the 52nd percentile for low minority zip codes.
The outcomes for Black Americans because of this bias are higher interest rates on home loans and auto loans; longer loan terms; increased debt collection default lawsuits, and an increase in the use of predatory lenders. FICO has defended the system stating that income, property, education, and employment are not evenly distributed across society and it is irrational to think an objective measure would not exhibit these discrepancies. Tamara Nopper, sociologist at The Center for Critical Race & Digital Studies has stated that to solve the true issue of racism is not just to regulate it, as politics focus on, but to eliminate it in favor of public-owned banks that serve the community instead of shareholders.
A related concept of insurance scoring has also been shown to discriminate along racial lines, disproportionately harming black and Latino populations.
Employment
Employers are unable to access credit scores on the credit reports sold for the purposes of employment screening but are able to acquire debt and payment history. Credit reports are legal to use for employment screening in all states, although some have passed legislation limiting the practice to only certain positions. John Ulzheimer, president of The Ulzheimer Group and the founder of CreditExpertWitness.com, stated in a CNBC report that, "[credit scores] indicate if you're in financial distress. These are attributes that are important to employers. For example, would you want to hire someone in your accounting department who can't manage their own obligations?". This approach has been noted as a discriminatory issue as the decisions can prevent one from gaining employment. Eric Rosenberg, director of state government relations for TransUnion, has also stated that there is no research that shows any statistical correlation between what's in somebody's credit report and their job performance or their likelihood to commit fraud. The National Consumer Law Center (NCLC) has stated that credit scoring perpetuates economic inequality by controlling access to opportunities in the future as well as important necessities such as employment.
In 2009, TransUnion representatives testified before the Connecticut legislature about their practice of marketing credit score reports to employers for use in the hiring process. Legislators in at least twelve states introduced bills, and three states have passed laws, to limit the use of credit check during the hiring process.
Medical debt holders
Medical debt is often a barrier to obtaining credit, housing, and employment. Because medical situations are often unexpected, they can cause an individual or family to experience financial distress, especially when unanticipated or "surprise" bills are unable to be paid.
The debt is reported to credit bureaus due to payment delays, insurance disputes, confusion, or the dysfunctional nature of the US healthcare finance system.
Credit scores treat medical debts the same as any other debts despite their involuntary nature (unlike opening a credit card for example). Some states have implemented laws to protect consumers against medical debts affecting their scores ranging from:
Prohibiting the reporting of medical debt for a certain time period after billing.
Protections within payment plans for consumers.
Restriction of reporting of medical debt for uninsured or underinsured patients or for patients that are negotiating disputes with their health insurance company.
Requirements of notice when debt is reported.
Protections focused on vulnerable patients (such as children).
The NCLC recommends eight key requirements for policy reform: 1) expansion of public financial assistance; 2) financial assistance minimum standards; 3) large health care facilities must screen for eligibility for insurance; 4) language assistance for understanding the financial process; 5) payments start after 90 days; 6) clarification of contractual violations for a hospital's forgiveness of a patient's copay, coinsurance, etc.; 7) protecting family members from a loved ones debts; and 8) enforcement of the statute through a private right of action.
Student debt holders
The non-profit organization Student Debt Crisis along with Summer, a social impact startup that helps student debt holders published a national survey in 2018 that found 59% of respondents were prevented from making large purchases, 56% from buying a home, and 42% from buying a car. 58% reported that their credit scores had declined due to the debts, 28% were unable to start a business, 10% reported failing a credit check for a job prospect, and 13% failed a credit check for an apartment application. Rental application rejections and the inability to find sufficient housing is a well known consequence of credit scores as it leaves college graduates unable to participate in society. Even if loan payments are never late, debt-to-income ratios can be too high for landlords to approve an application. Buying a home can be even more difficult, if not impossible, as student loans are often as big as or larger than an average mortgage.
Inaccuracies and algorithmic subjectivity
Consumers in the US have very little control over how they are scored and even less ability to dispute unfair, biased, or inaccurate credit report assessments. Scoring is automated, which results in potential consequences, often lacking oversight. Credit reports by the three largest companies are commonly found to be incorrect with thousands of cases going to court each year. Federal law requires agencies to investigate disputed information; however, "the agencies have operated for decades with systems that make it nearly impossible to conduct a comprehensive investigation, attorneys and consumer advocates say. The law is so nuanced, they say, that credit bureaus can essentially wash their hands of meaningful review." In 2020, 280,000 complaints were filed to the CFPB regarding credit reporting error issues. One of the alleged reasons for the excess of errors, according to Matt Litt, consumer campaign director with U.S. Public Interest Research Group, is that the credit reporting agencies are not incentivized to fix them because consumers are not the customers, but are instead the product—lenders, landlords, and other businesses seeking credit information are the customers. CNBC reported that there is an "astounding number of errors in the credit reports that are the result of misaligned economic and legal incentives", and a public poll by the Morning Consult indicated (74%) a demand for new laws or regulations to deal with credit bureaus. CNBC proposed three solutions to the issue of inaccurate reports:
Liability for incorrect data must be changed as currently, there is no one held accountable and no penalties for not investigating disputes.
Credit reports should be free and proactively available for consumers to monitor for inaccuracies.
Expand the information usable by reports using big data.
A large percent of credit scores are estimated to have inaccuracies. A portion of the inaccuracies stem from misattribution errors from the intermixing of data due to similar names or information. Alternative data using personal data outside of the scope of traditional credit scoring is also known to contain inaccuracies. Further, none of this data collection, the methods, or the parameters used to determine creditworthiness are public information. Unfair judgements of creditworthiness creates an unfair and socially unjust system that restricts participation in society. These algorithmic inaccuracies driven by big data can have serious implications for human identity and status in society, a concept known as the "scored society".
Inaccuracy
Because a significant portion of the FICO score is determined by the ratio of credit used to credit available on credit card accounts, one way to increase the score is to increase the credit limits on one's credit card accounts. This has been criticized as it acts as a way to incentivize accumulation of debts and deincentivizes people from financing purchases themselves through saving, as well as normalizes the credit-debt system and consumerism.
Credit invisibility
The concept of "credit invisibility" (a term used by the Consumer Financial Protection Bureau, the CFPB) is factored into this as there are many individuals who do not use or need credit (usually the elderly), avoid using credit, or avoid participating in the credit system. Being credit invisible puts consumers at a disadvantage. Hispanic Americans are typically more likely to pay in cash and pool resources with extended family. None of this is visible to credit reporting agencies and therefore leaves Hispanics without the ability to make major purchases. Another group of Americans that are, "left in digital poorhouse," a phrase coined by social scientist Virginia Eubanks, are young—in particular, millennials. This is due to access versus ownership—unable to purchase because of low credit, they seek alternatives to buying cars or houses. They also do not use credit cards as much as cash and rely on mobile payment apps like Venmo. None of these transactions are captured by credit reporting agencies and leave students' credit invisible. Further, millennials report believing that being debt free is a sign of financial success. To build a credit score requires one to take on debt, acting effectively as a debt score.
Alternative scoring systems
Credit invisibility combined with the rise of big data and artificial intelligence has given rise to a new market that challenges the traditional FICO model of credit scoring. The use of alternative data has been pursued as a means to access more consumers, a form of market competition in an industry seeking greater profits. Controversy exists regarding the invasive nature of the technology. Some of the issues are summarized here:
Violation of due process may result as artificial intelligence scores may miscategorize consumers. Due process laws along with regulations based on this tradition must be used as a protective measure.
Credit scoring systems using AI lack transparency in decision making as the technology is patented.
Predictive algorithms run a high risk of being inaccurate and unfair, affecting peoples lives in discriminatory or arbitrary ways.
Alternative data collection can be invasive as it collects data beyond the scope of financial transactions (such as paying utility bills) to generate "digital characters" based on social media accounts or internet browsing history.
Violation of consumer protection and fair lending laws (as well as human and civil rights violations) may result as privacy and security may be jeopardized.
Big data is attempting to address the issue of traditional credit scoring's inability to accurately predict risk, "credit invisible" populations, and "thin file" populations (people that have very limited or outdated credit histories). The aim is to build credit histories based on alternate information; however, it may result in lower scores instead of no scores (especially for people who are low-income) due to financial prioritization such as getting behind on utilities for high-cost months in favor of critical items.
Policymakers and regulators must focus on data accuracy, verifiable predictiveness, and the potential for discrimination. Research strongly indicates none of these are being met by alternative credit scoring companies.
Redlining may return due to hidden biases in the algorithms.
The more data points used for a credit assessment, the greater the difficulty in transparency.
Poor predictor of risk
Credit scores are enhanced by having multiple credit cards, the use of credit cards, and having installment loans. However, financially secure individuals who do not use multiple credit cards, or who self-finance expenses, may be inaccurately assessed a lower credit score. Some have blamed lenders for inappropriately approving loans for subprime applicants, despite signs that people with poor scores were at high risk for not repaying the loan. By not considering whether the person could afford the payments if they were to increase in the future, many of these loans may have put the borrowers at risk of default. Some banks have reduced their reliance on FICO scoring. For example, Golden West Financial abandoned FICO scores for a more costly analysis of a potential borrower's assets and employment before giving a loan.
Non-transparency
Credit scoring technologies are not public information as they are proprietary trade secrets of the companies that invent them.
Regulation
Very little to no regulatory framework exists to ensure credit scoring algorithms are fair. It has been suggested that scored individuals need to be granted rights for the various steps in the scoring process such as the method of data collection, how the score is calculated, to whom the score is disseminated, as well as how the score is used. The Federal Trade Commission has also been targeted as the institution that should have greater regulatory oversight of the credit-scoring process as well as have access to credit-scoring systems to ensure fairness and accuracy.
Ethics, morality, and inequality
Credit scores have been criticized as a systematic way to measure morality. They track consumption choices over time and so they are used to reflect a person's ability to manage money. The classification system of credit scores "rewards consumers who belong to the right category", and excludes those who are on the fringes of classification; credit scores nominally intended as a gauge of reliability as a lender becomes instead a gauge of morality. Companies keep records of purchasing behavior, which suggests certain behavior patterns, some of which are rewarded and others are punished—usually in ways that broaden the economic and (perceived) moral gaps between richer and poorer persons. These punishments can include higher premiums, loss of privileges, poorer service, or higher interest rates, which ultimately affect credit score and purchasing power. This idea is similarly expressed with the Social Credit System in China as it acts as a tool to, [fix] moral decay" and "encourage positive economic and moral behaviours". The parallel between the two systems is that China's is outside of the market, while the United States' is within the market, so it goes noticed as an issue of morality. Jonathan Cinnamon of the University of Exeter states the unfairness of credit scores and how they impeded our ability to function in society:
Jackie Wang of the University of Southern California writes in Carceral Capitalism about how credit scores ultimately make moral judgments that increase inequality:
Marion Fourcade of the University of California Berkeley and Kieran Healy of Duke University discuss the concept of credit scoring as a tool for moral judgement, übercapital, as well as a form of class struggle.
Frank Pasquale, a legal expert on artificial intelligence, algorithms, and machine learning and Danielle Citron of the University of Virginia School of Law contend that the algorithms used to decide credit scores need moral justification because of the large impact they can have on individuals.
See also
Dodd–Frank Wall Street Reform and Consumer Protection Act
Fair Credit Reporting Act
Financial crisis of 2007–2008
Financialization
Right to explanation
Subprime mortgage crisis
References
Further reading
Credit scoring
Personal finance
Inequality
Neoliberalism
Discrimination
Finance in the United States
Credit scoring systems | Criticism of credit scoring systems in the United States | [
"Biology"
] | 4,402 | [
"Behavior",
"Aggression",
"Discrimination"
] |
67,917,744 | https://en.wikipedia.org/wiki/UGC%206665 | UGC 6665 (Arp 161) is a spiral field galaxy in the constellation Virgo. It is an estimated 265 million light-years from the Milky Way, and is listed in Halton Arp's Atlas of Peculiar Galaxies as number 161.
UGC 6665 is a blue compact dwarf (BCD) galaxy. Like some other BCDs, it has an unusually high ratio of nitrogen to oxygen.
References
Peculiar galaxies
006665
Virgo (constellation)
Spiral galaxies | UGC 6665 | [
"Astronomy"
] | 99 | [
"Virgo (constellation)",
"Constellations"
] |
67,918,018 | https://en.wikipedia.org/wiki/HD%20150193 | HD 150193 is a binary star system in the constellation of Ophiuchus. The primary star was identified as a Herbig Ae/Be star with a strong solar wind, losing approximately a tenth of solar mass per million years. It does host a very small debris disk, likely due to disk truncation by the nearby stellar companion. The disk is inclined 38° to the plane of sky. It appears to be highly evolved and asymmetric, with indications of flattening and grains growth.
The companion HD 150193B, is a T Tauri young star with a projected separation of 166 AU.
The binary HD 150193 is part of the Upper Scorpius subgroup of Scorpius–Centaurus star-forming region.
References
Ophiuchus
Herbig Ae/Be stars
Scorpius–Centaurus association
150193
081624
CD-23 12887
Ophiuchi, V2307
J16401792-2353452
Binary stars
T Tauri stars
Orion variables | HD 150193 | [
"Astronomy"
] | 214 | [
"Ophiuchus",
"Constellations"
] |
67,920,511 | https://en.wikipedia.org/wiki/Swargadwara | Swargadwara (; ) is a cremation ground and one of India's most auspicious mortuary sites. It is located at on the shore of Bay of Bengal (called Mahodadhi), about a mile to the south of Jagannath Temple and southeastern area of the city Puri in Odisha. Where anyone can watch the cremations from a respectful distance. Generally the Hindus believe that, by cremated in Swargadwara, they will go to heaven for liberating their soul and will attain ultimate salvation.
History
Kapila Samhita mentioned that the Swargadwara one of a seven sacred places from the list, where Brahma was embodied from Heaven on earth with Indradyumna for consecrating the holy Trinity.
According to scriptures, the Daru Brahma (Soul stuff), from which the three main deities of the Jagannath temple are carved out, floated to the beach at Swargadwara.In every Amavasya Lord Jagannath in visiting sea which is said to be the in-law house of the Lord, through this holy cremation ground. On this holy site situated the temple of Goddess Smasana Kali. Goddess Kali act as the guard of Swargadwar and stand as the proof for all Heaven going Soul.
References
Cremation
Hindu holy cities
Jagannath Temple Complex
Puri
Crematoria in India | Swargadwara | [
"Chemistry"
] | 296 | [
"Cremation",
"Incineration"
] |
67,921,624 | https://en.wikipedia.org/wiki/Entomophthoraceae | Entomophthoraceae is a family of fungi in the order Entomophthorales. This has been supported by molecular phylogenetic analysis (Gryganskyi et al. 2012). Most species in the family are obligately entomopathogenic. There are two subfamilies, Erynioideae and Entomophthoroideae, which were proposed in 2005.
Genera
Batkoa – 10 spp.
Entomophaga – 22 spp.
Entomophthora – 63 spp.
Erynia – 27 spp.
Eryniopsis – 5 spp.
Furia – 16 spp.
Massospora – 5 spp.
Orthomyces – 1 sp.
Pandora Humber 2005 - 31 spp.
Strongwellsea – 8 spp.
Tarichium – 26 spp.
Zoophthora – 38 spp.
References
Entomophthorales
Fungus families
Taxa described in 1874 | Entomophthoraceae | [
"Biology"
] | 194 | [
"Fungus stubs",
"Fungi"
] |
67,923,090 | https://en.wikipedia.org/wiki/Euchloridae | Euchloridae is a family of sponges belonging to the order Cydippida.
Genera:
Euchlora Chun, 1880
References
Sponges | Euchloridae | [
"Biology"
] | 33 | [
"Sponges",
"Animals"
] |
67,923,723 | https://en.wikipedia.org/wiki/262%20%28number%29 | 262 (two hundred [and] sixty-two) is a natural number preceded by the number 261 and followed by 263. It has the prime factorization 2·131.
Mathematical properties
There are four divisors of this number, the divisors being , , , and 262 itself, which makes it a semiprime.
It is the sixth meandric number, and the ninth open meandric number.
As it cannot be divided into the sum of the proper divisors of any number, it is the 17th untouchable number.
As it eventually reaches 1 when replaced by the sum of the square of each digit, it is the 40th 10-happy number.
As 262 is 262 backwards, it is a palindromic number.
References
Integers | 262 (number) | [
"Mathematics"
] | 157 | [
"Elementary mathematics",
"Integers",
"Mathematical objects",
"Numbers"
] |
67,924,575 | https://en.wikipedia.org/wiki/HD%2072337 | HD 72337, also known as HR 3370, is a solitary, bluish-white hued star located in the southern constellation Volans. With an apparent magnitude of 5.51, it is faintly visible to the unaided eye but only under ideal conditions.
Velocity
Based on recent parallax measurements from the Gaia spacecraft, HD 72337 is currently located at a distance of 287 light years. The object made its closest approach 1.914 million years ago when it was 234 light years distant. At that distance, it brightened slightly to an apparent magnitude of 5.13. Currently, HR 3370 is receding with a heliocentric radial velocity of .
Properties
The stellar classification of HD 72337 is A0 V, indicating that it is an ordinary A-type main-sequence star. It has 2.25 times the radius of the Sun and a mass of . It radiates at 42.5 times the luminosity of the Sun from its photosphere at an effective temperature of . Like many hot stars, HD 72337 rotates rapidly with a projected rotational velocity of , and is estimated to be 265 million years old.
References
A-type main-sequence stars
72337
3370
041451
Volans
Durchmusterung objects | HD 72337 | [
"Astronomy"
] | 264 | [
"Volans",
"Constellations"
] |
67,924,712 | https://en.wikipedia.org/wiki/Heterogeneous%20metal%20catalyzed%20cross-coupling | Heterogeneous metal catalyzed cross-coupling is a subset of metal catalyzed cross-coupling in which a heterogeneous metal catalyst is employed. Generally heterogeneous cross-coupling catalysts consist of a metal dispersed on an inorganic surface or bound to a polymeric support with ligands. Heterogeneous catalysts provide potential benefits over homogeneous catalysts in chemical processes in which cross-coupling is commonly employed—particularly in the fine chemical industry—including recyclability and lower metal contamination of reaction products. However, for cross-coupling reactions, heterogeneous metal catalysts can suffer from pitfalls such as poor turnover and poor substrate scope, which have limited their utility in cross-coupling reactions to date relative to homogeneous catalysts. Heterogeneous metal catalyzed cross-couplings, as with homogeneous metal catalyzed ones, most commonly use Pd as the cross-coupling metal.
Reaction mechanism and implications
Pd-catalyzed cross-coupling reactions catalyzed by a heterogeneous catalyst are thought to generally proceed, not on the surface of the solid catalyst, but in the solution phase. The solution-phase intermediates are not necessarily distinguishable from those obtained during homogeneous cross-couplings – for example, a heterogeneous Pd-catalyzed Suzuki reaction still proceeds via oxidative addition of the electrophile by Pd(0), transmetallation of a boronate, and reductive elimination to give product and regenerate Pd(0) (Figure 1A). The activity of heterogeneous catalysts in cross-coupling seems to be tied to the ability of the electrophile (usually an aryl halide) to undergo oxidative addition with an atom of Pd(0), whether on the solid catalyst surface or already in solution, after which the rest of the catalytic cycle will take place – in solution.The role of the solid phase in heterogeneous metal catalyzed cross-coupling, then, is more subtle than one might expect. Rather than enabling the productive catalytic cycle, the solid phase acts as a reservoir of Pd that is accessible to the productive catalytic cycle. For heterogeneous catalytic cross-coupling which involves unligated Pd (for example, when Pd/C is used as the catalyst), there exists a significant equilibrium that partitions Pd(0) between atomic, solution-phase monomers, surface-bound Pd, colloidal Pd and higher order Pd aggregates (Figure 1B). Aggregation of Pd atoms into clusters ultimately leads to irreversible precipitation of insoluble metallic Pd, which limits the maximum turnover number that can be achieved. An effective heterogeneous cross-coupling catalyst will recapture monomeric Pd or lower order oligomers and colloids onto the solid phase in order to maintain low concentrations of these species in solution, disfavouring aggregation and favouring instead the productive elementary steps of cross-coupling. This may explain the (perhaps counterintuitive) observation that lower catalyst loadings can improve turnover number for a heterogeneous cross-coupling catalyst system (Pd on porous glass, in the Heck reactions of 4-bromoacetophenone at 180 °C).
The solid-phase to solution-phase mass transfer requirement for Pd in most heterogeneous cross-couplings has further implications. Because the supported ligand for a polymer-supported catalyst is not optimized for reactivity, and because the productive catalytic cycle usually ignores the supported ligand entirely even if present, “difficult” cross-coupling reactions which require fine tuning of the electronic and steric properties of the Pd catalyst – via expensive, designer ligands – are scarcely reported in a heterogeneous context. A 2021 survey of heterogeneous metal catalyzed cross-couplings in the fine chemical industry reported, out of 22 examples, 19 Suzuki or Heck reactions, which included only 2 examples with N-basic heterocycles, and only 4 examples with a singly-ortho-substituted electrophile (representative example in Scheme 1). In nearly all these cases, reactions were initially developed with a homogeneous Pd catalyst (typically Pd(OAc)2 with either no exogenous ligand or PPh3 as ligand) on smaller scale, and only evaluated with heterogeneous Pd catalysts, (typically Pd/C or Pd black) for scaleup to decagram to multi-hundred-kilo scales, once process considerations such as process mass intensity and separation costs became significant. Notably, no polymer-supported catalysts were used; for these real-world examples of heterogeneous catalytic cross-coupling on scale, inorganic heterogeneous catalysts (such as Pd/C) are far cheaper and more robust than polymer-supported ligated Pd catalysts, and thus more commonly employed.
When designing a polymer-ligand solid support for Pd, the ligands should not simply be immobilized variants of homogeneous ligands which effect catalysis in the presence of Pd. Rather, immobilized ligands should optimize the redeposition of Pd onto the solid phase at the end of each catalytic cycle in a catalytically active form that is ready for a subsequent catalytic cycle. Ligand sets which are rarely seen in homogeneous cross-coupling, then, appear in heterogeneous ligand-containing Pd catalysts. For example, Buchmeiser et al. have reported high turnover N,N-bidentate ligands (Figure 2) which achieve turnover numbers (TONs) of >105 in the Heck reactions of iodobenzene, and TON ca. 103 in the amination of bromobenzene. These TONs are competitive with even the best solution TONs, giving clear advantages for this system for separation of the product from catalyst post-reaction.
Kinetics
The “shuttling” kinetics of Pd mass transfer (from solid phase to solution phase and back to solid phase) have been verified by three-phase test experiments, while the solution-phase catalytic activity which characterizes most heterogeneous cross-coupling has been verified by TEM, hot filtration, and poisoning experiments. However, truly heterogeneous cross-coupling systems may exist. Poyatos et al. immobilized a Pd pincer carbene complex (Figure 3) on MK-10 clay and observed that while high TON (ca. 103) and TOF was maintained relative to the soluble catalyst, no activity was found in the solution for the supported catalyst – a strong indicator of a fully heterogeneous catalytic mechanism.
Heterogeneous metal catalyzed cross-coupling in flow vs batch
For batch cross-couplings which use immobilized Pd, the concentration of solution-phase Pd increases dramatically when the reaction commences (as Pd is transferred out of the solid phase), and has decreased dramatically by the time full conversion has been achieved (by readsorption or precipitation onto the solid support). Such a kinetic profile matches the processing requirements of a batch process – although some amount of metal remains in solution post-reaction, the supported Pd catalyst can usually be recycled several times, despite the limitations described above.
In contrast, continuous flow systems do not allow for effective metal redeposition on the solid support; the reaction stream will transport the Pd through the support due to continuous metal leaching/readsorption (Figure 4). Cumulative periods of operation inevitably result in significant metal leaching from the flow system, depleting the supported catalyst's activity and giving low recyclability, with – typically – no particular benefit for reactivity.
In principle, it is possible for the metal leaching inherent to continuous flow cross-coupling to be avoided. Plucinkski and coworkers developed a continuous Mizoroki-Heck and hydrogenation sequence consisting of two separated packed-bed reactors containing Pd/C. Because the Pd/C-catalyzed hydrogenation proceeds via a heterogeneous mechanism, metal leaching due to the second hydrogenation step is minimal, and Pd leached from the first part of the reactor during the Heck coupling can be recaptured by the second packed bed during the hydrogenation. By cycling the direction of flow between forward and reverse, catalytic activity could be maintained over two consecutive experiments, although a greater number of cycles would be desirable in order to vindicate this strategy for increasing turnover in solid-supported flow catalysts for cross-coupling.
Separation
Heterogeneous catalysts are easily removed from a reaction mixture by filtration. Although some amount of metal catalyst typically remains in the product from leaching, these amounts tend to be lower than those remaining after workup of a homogenous metal-catalyzed cross-coupling.
Magnetic removal
A heterogeneous catalyst consisting of Pd supported by silica-coated Fe2O3/Fe3O4 nanoparticles allows the reaction to be heated by electrical induction, and also allows facile magnetic separation of catalyst and product post-reaction. Copper ferrite has been reported as a heterocycle arylation catalyst and can be similarly separated from the reaction with a magnet.
Recycling
Heterogeneous cross-coupling catalysts typically lose some portion of activity to metal leaching between different runs as a result of the solution-phase catalytic cycle (see above), and hence can only be recycled a finite number of times.
Multiple groups have pointed out that the need for recycling is obviated at extremely high turnover and low catalyst loading, since in these cases the catalyst cost is negligible relative to the cost of other reaction components. As a result, for most cross-coupling reactions, in which heterogeneous catalysts generally require higher loadings than equivalent homogeneous ones, the benefits of heterogeneous catalysts afforded by the greater ease of recycling may be outweighed by the disadvantages – higher catalyst loadings, and the additional process costs. Additionally, when catalyst loadings are lower than 10 ppm – the regulatory limit for several metals including Pd in pharmaceutical APIs – separation of the metal following the reaction does not even need to be performed. This nullifies another of the commonly perceived advantages of heterogeneous catalysts over their homogeneous counterparts.
References
Organometallic chemistry
Carbon-carbon bond forming reactions
Catalysis | Heterogeneous metal catalyzed cross-coupling | [
"Chemistry"
] | 2,118 | [
"Catalysis",
"Carbon-carbon bond forming reactions",
"Coupling reactions",
"Organic reactions",
"Chemical kinetics",
"Organometallic chemistry"
] |
67,925,142 | https://en.wikipedia.org/wiki/Shuttle%20catalysis | Shuttle catalysis is used to describe catalytic reactions where a chemical entity of a donor molecule is transferred to an acceptor molecule. In these reactions, while the number of chemical bonds of each reactant changes, the types and total number of chemical bonds remain constant over the course of the reaction. In contrast to many organic reactions which exothermicity practically renders them irreversible, reactions operated under shuttle catalysis are often reversible. However, the position of the equilibrium can be driven to the product side through Le Chatelier’s principle. The driving forces for this equilibrium shift are typically the formation of a gas/precipitation, the use of high ground-state energy reactants or the formation of stabilized products or the excess equivalents of a reactant.
The relocation of shuttled entities is often mediated by a transition metal catalyst, which serves to functionalize or defunctionalize a compound of interest. An advantage to this process is that it excludes the process of handling toxic or reactive raw chemical entities. However, these reactions require the development of catalytic systems that can efficiently deliver the shuttled entities between the reactants under mild conditions through a sequence of elementary steps.
Applications
Transfer hydrogenation
Transfer hydrogenation has been extensively studied to reduce various functional groups without requiring hazardous pressurized H2.
Transfer hydroacylation
In 1999, Chul-Ho Jun and Hyuk Lee reported the first example of hydroacylation through shuttle catalysis. In this example, 3-methyl-2-aminopyridine was used to activate the acyl group as well as coordinate to the rhodium catalyst, promoting C–C bond cleavage to eventually enable aldehyde transfer from a ketone to an alkene. The driving force of this reaction is the excess presence of alkenes and the formation of stable styrenes/extrusion of volatile ethylene. This method doesn’t require the use of toxic and self-reacting aldehydes such as acetaldehyde in the traditional hydroacylation procedures.
Transfer hydroformylation
Hydroformylation is a classical transition-metal catalyzed reaction, and it has been widely employed in industrial settings. However, a drawback of this reaction is the requirement of the hazardous mixture of H2/CO. For that reason, a process to replace H2/CO gas with a non-hazardous aldehyde is sought after.
In 1999, Christian P. Lenges and Maurice Brookhart reported isovaleraldehyde as a suitable surrogate for H2/CO transfer to 3,3-dimethyl-1-butene by using a rhodium(I) catalyst.
The reverse of this process was rendered catalytic by Vy M. Dong and co-workers in 2015. They performed dehydroformylation on aldehydes to achieve the corresponding alkenes. For this transformation, they used either norbornene or norbornadiene as a H2/CO acceptor, promoting reactivity through strain-release.
Transfer hydrocyanation
To replace the use of toxic hydrocyanide (HCN) gas or surrogates such as acetone cyanohydrin, Bill Morandi and co-workers developed a hydrocyanation strategy using shuttle catalysis. In this example, they use isovaleronitrile as a HCN surrogate under nickel/aluminum co-catalyzed conditions to afford hydrocyanation reactions of various alkenes. The use of isovaleronitrile allows careful control of HCN concentration, and the formation of volatile isobutylene is the driving force for the reaction.
Others
Other chemical entities including arenes, CO/HCl, HMgBr, H2Zn, H2O, carbene, silylene, sulfenium have also been shuttled under this catalysis platform.
References
Catalysis | Shuttle catalysis | [
"Chemistry"
] | 803 | [
"Catalysis",
"Chemical kinetics"
] |
67,925,573 | https://en.wikipedia.org/wiki/Conia-ene%20reaction | In organic chemistry, the Conia-ene reaction is an intramolecular cyclization reaction between an enolizable carbonyl such as an ester or ketone and an alkyne or alkene, giving a cyclic product with a new carbon-carbon bond. As initially reported by J. M. Conia and P. Le Perchec, the Conia-ene reaction is a heteroatom analog of the ene reaction that uses an enol as the ene component. Like other pericyclic reactions, the original Conia-ene reaction required high temperatures to proceed, limiting its wider application. However, subsequent improvements, particularly in metal catalysis, have led to significant expansion of reaction scope. Consequently, various forms of the Conia-ene reaction have been employed in the synthesis of complex molecules and natural products.
History and mechanism
In the late 1960s, the laboratory of chemist Jean-Marie Conia investigated small carbocyclic molecules, specifically as products of ene-type reactions with carbonyls. These efforts culminated in a 1975 review paper titled “The Thermal Cyclisation of Unsaturated Carbonyl Compounds.”
In its original manifestation, the Conia-ene reaction comprised the intramolecular cyclization of ε,ζ-unsaturated ketones or aldehydes to functionalized cyclopentanes upon intense heating. The proposed mechanism invoked a six-membered, ene reaction-like transition state in which the enol tautomer reacts concertedly with the pendant alkene.
The same conditions were found to give six- and nine-membered rings with the appropriate substrates, although with lower yields and diastereoselectivity. In the case of γ,δ- and δ,ε-unsaturated ketones, equilibrium favored the linear product over the cyclopropane or cyclobutane. Alkynyl ketones were also found to cyclize under thermal conditions, giving a mixture of the conjugated and skipped cyclic enones.
Two key drawbacks prevented wider implementation of the initial Conia-ene reaction. First, molecules with additional functional groups were often incompatible with the high temperatures required for conversion. Second, regio- and diastereoselectivity depended entirely on the substrate, offering little to no control over the orientation of the product.
Advancements
In the decades after the discovery of the Conia-ene reaction, several improvements allowed for milder reaction conditions and greater control of product stereo- and regiochemistry. For example, the carbonyl component, formerly a ketone or aldehyde, became a substituted β-ketoester or malonate ester. Such carbonyls enolize much more readily, yielding better access to the desired enol tautomer. Additionally, the alkene component was replaced with an alkyne, which not only gave better cyclization in accordance with Baldwin’s rules, but also furnished a product containing an alkene that served as a useful handle for further transformations. Finally, recent efforts have featured metal-mediated and metal-catalyzed Conia-ene reactions that can be rendered asymmetric using chiral ligands.
Activation modes
These advancements have produced five main types of Conia-ene reactions characterized by the operative activation mode: namely, enolate, alkyne, or ene-yne activation, and one- or two-metal dual activation. Note that though the mechanisms of Conia-ene variants differ from the initial ene-like cyclization, they are still considered Conia-ene or Conia-ene-type reactions. In addition, due to the complexity of some Conia-ene reaction systems, the true mechanism may lay somewhere between several different activation modes.
Enolate activation
Enolate activation is the simplest Conia-ene activation mode. In this mode, the carbonyl starting material is treated with a strong base, such as nBuLi, NaH, or tBuOK, to form a metal-stabilized enolate, which then attacks the tethered alkyne and transfers the metal cation. An early example of enolate activation was reported by Taguchi and coworkers in 1999. The authors found that in the presence of catalytic base, alkynyl-substituted malonate esters undergo facile cyclization to the corresponding cyclopentanes. High yields were also obtained with substituted cyanoacetate, sulfonylacetate, and phosphonoacetate analogs.
Alkyne activation
In Conia-ene reactions proceeding via alkyne activation, a suitable late transition metal (Au, Ag, Pt, Pd) coordinates to the alkyne and increases its electrophilicity; thus, the enol tautomer of the carbonyl can attack more readily. Toste et al. pioneered two of the first examples of alkyne activation in 2004. Using a cationic Au(I) complex, the authors formed a wide variety of cyclized products from linear β-ketoester starting materials. Notably, the reactions are run under mild conditions and give high diastereoselectivity. Moreover, by shortening the alkyne tether from three carbons to two, substituted cyclopentenes can also be accessed.
Ene-yne activation
In ene-yne activation, the least common of the five modes, a single metal species coordinates with the enol alkene and the tethered alkyne, simultaneously activating both moieties for reaction. Nickel, cobalt, and rhenium complexes have all been employed in this manner. A representative example was reported by Malacria et al. in 1994, in which an alkynyl substituted β-ketoester was treated with cyclopentadienyl cobalt complex and irradiation to give disubstituted methylene cyclopentane.
One-metal dual activation
To effect dual activation by a single metal, the same metal species that activates the enolate also interacts with the alkyne. Though the precise mechanisms are poorly understood and likely vary from case to case, metals such as In, Zn, Fe, and Cu are proposed to operate via this mode. One reaction system thought to proceed via one-metal dual activation is that developed by Shaw et al. in 2014. Using a catalytic Fe(III)-(Salen) complex, Shaw and coworkers were able to access chiral cyclopentanes from an array of alkynyl-tethered β-ketoesters and analogs thereof. The reaction tolerated a wide range of ketones (phenyl, homoallyl, cyclopropyl, 2-furyl, etc.), esters (ethyl, tert-butyl, etc.), and ester analogs (nitro, , cyano, sulfonyl, etc.).
Two-metal dual activation
Two-metal dual activation represents the combination of the enolate activation mode and the alkyne activation mode into a single reaction system. Generally, a hard, oxophilic metal (K, Na, Ag) activates the enolate oxygen, while a soft, carbophilic metal (Pd, Cu, Mo) coordinates with the alkyne. In some instances, however, the precise role of each metal is unclear. For example, in a 2005 study Toste et al. found that treatment of an alkynyl-tethered β-ketoester with a Pd(II) phosphine complex and Yb(OTf) effected asymmetric cyclization to the corresponding cyclopentane. It is proposed that a Pd-enolate adds into a Yb-activated alkyne, though there is also precedent for Pd activation of alkynes.
Applications in total synthesis
Following their development of Au-catalyzed Conia-ene reactions, Toste and coworkers employed such a transformation toward the alkaloid natural product lycopladine A. Starting from chiral cyclohexenone 1, a series of enone functionalizations gave silyl enol ether 2 as the Conia-ene precursor. To effect cyclization, 2 was treated with catalytic AuCl(PPh) and AgBF to furnish vinyl iodide 3 in high yield as a single diastereomer. The remainder of the molecule was completed in three steps to give (+)-lycopladine A in eight steps and 17% overall yield.
In 2012, Carreira et al. synthesized , a halogenated terpene isolated from the red algae Laurencia majuscula, and employed Au-catalyzed Conia-ene cyclization as the penultimate step. Having obtained silyl enol ether 7 in 11 steps from bicycle 6, itself the product of a Diels–Alder cycloaddition between 4 and enone 5, the authors subject 7 to 50 mol% Echavarren’s catalyst to deliver tricycle 8 in 65% yield. This compound is then elaborated to by chlorination of the exo-methylene.
In 2020, Yang and coworkers employed a diastereoselective Conia-ene reaction during their asymmetric synthesis of (+)-waihoensene, a structurally dense terpenoid from Podocarpus totara var. waihoensis, first synthesized by the Lee group in 2017. Vinylogous ester 9 was first functionalized in six steps to chiral Conia-ene precursor 10. Subsequent treatment of 10 with tBuOK in DMSO gave bicycle 11 in 83% yield as a single diastereomer. This compound then required eight additional transformations to reach (+)-waihoensene in 15 steps and 4% overall yield.
References
Organic reactions
Reaction mechanisms | Conia-ene reaction | [
"Chemistry"
] | 2,079 | [
"Reaction mechanisms",
"Chemical kinetics",
"Physical organic chemistry",
"Organic reactions"
] |
78,086,135 | https://en.wikipedia.org/wiki/REBELS-25 | REBELS-25 is a massive, star-forming rotating disc galaxy with a redshift of 7.31.
It was discovered using the Atacama Large Millimeter/submillimeter Array (ALMA), notice of its discovery was published in the Monthly Notices of the Royal Astronomical Society. REBELS-25 existed just 700 million years after the Big Bang.
The discovery of such an ancient galaxy not only makes it the oldest known galaxy, but it is another piece of mounting evidence that suggests cosmologists need to revise their previous notions on galactic evolution.
REBELS-25 is very complex compared to what was expected for a galaxy of its age: researchers discovered that it rotates (with the help of blueshift and redshift), and also shows traces of spiral arms as "modern" galaxies, like the Milky Way, has. Lucie Rowland, lead author of the REBELS-25 discovery paper, said about this ancient galaxy that "Seeing a galaxy with such similarities to our own Milky Way, that is strongly rotation-dominated, challenges our understanding of how quickly galaxies in the early Universe evolve into the orderly galaxies of today's cosmos".
References
Galaxies
Sextans
James Webb Space Telescope
Astronomical objects discovered in 2024
Galaxies discovered in 2024 | REBELS-25 | [
"Astronomy"
] | 254 | [
"Space telescopes",
"Sextans",
"James Webb Space Telescope",
"Constellations"
] |
78,086,323 | https://en.wikipedia.org/wiki/Maria%20Santore | Maria Monica Santore is an American materials scientist whose research involves the surfaces of soft materials, including adhesion, lubrication, membrane assembly, and nanoscale patterns on the surfaces of microparticles. She is a professor of polymer science and engineering at the University of Massachusetts Amherst.
Education and career
Santore majored in chemical engineering at Carnegie Mellon University, graduating in 1985. She completed a Ph.D. in chemical engineering at Princeton University in 1989, under the supervision of William B. Russel.
She was a postdoctoral researcher at the National Institute of Standards and Technology before joining Lehigh University as a Dana Assistant Professor of Chemical Engineering. She earned tenure at Lehigh as an associate professor, and was named the Class of 1961 Chaired Associate Professor, before moving to the University of Massachusetts Amherst as a full professor.
Recognition
Santore was named as a Fellow of the American Physical Society (APS) in 2005, after a nomination from the APS Division of Polymer Physics, "for elegant fundamental experiments elucidating polymer and protein dynamics at interfaces and their roles in colloidal and biomaterial adhesion". She is a 2010 Fellow of the American Chemical Society in its Division of Polymeric Materials Science and Engineering, and a 2012 Fellow of the American Association for the Advancement of Science.
References
External links
Santore Research Group
Year of birth missing (living people)
Living people
American materials scientists
American women engineers
Women materials scientists and engineers
Carnegie Mellon University alumni
Princeton University alumni
Lehigh University faculty
University of Massachusetts Amherst faculty
Fellows of the American Association for the Advancement of Science
Fellows of the American Chemical Society
Fellows of the American Physical Society | Maria Santore | [
"Materials_science",
"Technology"
] | 328 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
78,086,913 | https://en.wikipedia.org/wiki/O-Pivalylbufotenine | O-Pivalylbufotenine, or bufotenine O-pivalate, also known as 5-pivaloxy-N,N-dimethyltryptamine or O-pivalyl-N,N-dimethylserotonin, is a synthetic tryptamine derivative and putative serotonergic psychedelic. It is the O-pivalyl analogue of the naturally occurring but peripherally selective serotonergic tryptamine bufotenine (5-hydroxy-N,N-dimethyltrypamine or N,N-dimethylserotonin) and is thought to act as a centrally penetrant prodrug of bufotenine.
O-Pivalylbufotenine shows psychedelic-like effects in animals but is less active than anticipated, perhaps due to its high lipophilicity and, by extension, high plasma protein binding and ester hydrolysis into bufotenine prior to crossing the blood–brain barrier. In addition to theoretically acting as a prodrug of bufotenine, which is a non-selective serotonin receptor agonist, O-pivalylbufotenine may also interact directly with certain serotonin receptors.
Besides O-pivalylbufotenine, other bufotenine O-acyl esters and putative or confirmed bufotenine prodrugs, such as O-acetylbufotenine among others, have been developed and studied.
O-Pivalylbufotenine was first described in the scientific literature by 1979.
See also
4-AcO-DMT
α-Methyltryptophan
Neurotransmitter prodrug
References
Neurotransmitter precursors
Pivalate esters
Prodrugs
Psychedelic tryptamines
Serotonin receptor agonists
Dimethylamino compounds | O-Pivalylbufotenine | [
"Chemistry"
] | 397 | [
"Chemicals in medicine",
"Prodrugs"
] |
78,086,975 | https://en.wikipedia.org/wiki/Tesla%20Cybercab | The Tesla Cybercab, also known as the Robotaxi, is an upcoming two-passenger battery-electric self-driving car under development by Tesla. The vehicle is planned to be fully autonomous. The prototype vehicles have no steering wheel or pedals.
A concept version of the Cybercab was unveiled in October 2024, with 20 prototypes providing short rides to attendees of the announcement event. Tesla reports production is planned to commence sometime before 2027.
History
Background
In 2019, Tesla CEO Elon Musk stated that he believed Tesla would have one million autonomous robotaxis operating on public roads by the end of 2020; observers speculated that he meant converting already sold Tesla vehicles to be autonomous.
Since approximately 2020, Tesla has made public statements about a mass market electric car product that would follow the Model Y and would be considerably cheaper than the Model 3. In 2022, Musk was advocating inside the company that the robotaxi would be Tesla's next vehicle, but by September 2022, he had reluctantly accepted the recommendation of Tesla executives Franz von Holzhausen and Lars Moravy that the next-generation vehicle platform should support both a small, inexpensive, mass-market car and a robotaxi that would be built with no steering wheel at all, and that both could be manufactured on the platform and use the same next-generation vehicle assembly line. In October 2022, the company stated publicly that the Tesla engineering team had turned its focus to the new platform, and that the company expected the platform would enable cars to be half of the price of the Tesla Model 3 or Y.
In April 2024, Musk announced that the Robotaxi reveal would take place in August, subsequently delayed to October.
Announcement
Musk unveiled the Cybercab at the Tesla We, Robot event held October 10, 2024, at Warner Bros. Studios Burbank in California, where 20 concept Cybercabs were autonomously driving around the studio outlot at night and giving rides to attendees of the event. Musk stated that Tesla intends to produce the Cybercab before 2027. The final name of the vehicle remains unclear, as Tesla used both "Robotaxi" and "Cybercab" throughout the event to refer to the cars. Tesla also demonstrated their humanoid robot, Optimus, at the event and showed off a single concept prototype of a Robovan that could reportedly hold as many as 20 passengers.
The concept Cybercab shown was a two-passenger car, it had two butterfly doors but no door handles as the doors opened automatically. The car had a hatchback opening for cargo, with no external charge port showing on the prototype vehicles. The car had no rear window and no side view mirrors.
The production vehicle design will include inductive charging.
Investor reaction to the announcement was muted, particularly given the long time frame between the announcement and expected start of production. New Scientist noted the Cybercab will not be available for two years while the Waymo self-driving cars are operating on streets today.
On the Tesla investor call on October 23, 2024, Tesla said they were aiming to be in volume production with Cybercab by the end of 2026, and that the annual production goal was 2 million Cybercabs per year, when several factories are at full design capacity.
In October 2024, Alcon Entertainment, a production company that worked on Blade Runner 2049 (2017), sued Musk for apparent similarities between Tesla's marketing of the Cybercab and the film.
Description
The future Tesla Cybercab specs will include the following, according to Tesla:
two-passenger car
autonomous operation only; no steering wheel or pedals accessible to passengers
range:
inductive charging with efficiency well above 90%; Musk: "there is no meaningful efficiency difference between inductive and conductive charging if the system is designed right."
battery capacity:
Other characteristics:
expected efficiency
A Tesla ridehailing service, in limited internal testing in October 2024
References
Cybercab
Battery electric vehicles
Self-driving cars
Unreleased products
Taxi vehicles
Sedans
Concept cars | Tesla Cybercab | [
"Engineering"
] | 831 | [
"Automotive engineering",
"Self-driving cars"
] |
78,087,169 | https://en.wikipedia.org/wiki/3-Hydroxypropionate/4-hydroxybutyrate%20cycle | The 3-Hydroxypropionate/4-hydroxybutyrate cycle, also known as the 3HP/4HB cycle, is a specialized carbon fixation process used by some archaea, including Thermoproteota. For these organisms to survive and grow autotrophically in hostile settings, such as hydrothermal vents, this cycle is essential. Carbon dioxide () is effectively transformed by the process into organic chemicals like acetyl-CoA, which can then be utilized for growth and energy production. This route is specific to organisms that fix in high-temperature, low-oxygen settings, in contrast to the more well-known Calvin cycle which does not perform as well at fixing under these conditions.
Steps
The 3-hydroxypropionate/4-hydroxybutyrate cycle is one of six known carbon fixation mechanisms. One of the most energy-efficient processes for transforming inorganic carbon () into organic compounds, especially in thermal and acidic environments, was initially discovered in the archaea Thermoproteota.
There are two primary sections to this pathway:
The carboxylation of acetyl-CoA yields malonyl-CoA, which is then transformed into intermediates that feed into the subsequent cycle in the 3-hydroxypropionate cycle.
Acetyl-CoA is created from intermediates such as succinyl-CoA and 4-hydroxybutyrate in the 4-Hydroxybutyrate cycle, which eventually regenerates the cycle by synthesizing organic molecules for energy and cellular development.
Key intermediates and enzymatic reactions
The cycle starts when the enzyme acetyl-CoA carboxylase catalyzes the carboxylation of acetyl-CoA to malonyl-CoA. Subsequently, this intermediate is converted into propionyl-CoA and other organic molecules. The cycle is completed in the second portion by regenerating acetyl-CoA using intermediates like succinyl-CoA and 4-hydroxybutyrate. Acetyl-CoA and pyruvate, the cycle's end products, are essential for a number of metabolic processes, such as the citric acid cycle and fatty acid synthesis. The 3-HP/4-HB cycle is very effective for autotrophic carbon fixation under harsh circumstances because of the cyclical regeneration of acetyl-CoA.
Adaptation to extreme environments: The 3-HP/4-HB cycle-dependent species are usually found in settings where more traditional carbon fixation routes, including the Calvin cycle, would not function well. Among these are hydrothermal vents, which have high temperatures, low oxygen concentrations, and copious amounts of . By reducing adenosine triphosphate (ATP) and energy consumption during carbon fixation, the 3-HP/4-HB cycle helps organisms flourish and allows these archaea to maintain existence in some of the most hostile environments on Earth.
Comparison to other carbon fixation pathways
In high-temperature and low-oxygen environments, the 3-HP/4-HB cycle uses less energy than the Calvin cycle, which is common in plants and algae. The 3-HP/4-HB cycle is a perfect method for energy conservation in archaea compared to the Calvin cycle since it fixes carbon with fewer ATP molecules. The Calvin cycle requires 9 ATP and 6 NADPH to fix three molecules of into a triose phosphate, which is eventually converted to glucose. However, the 3-HP/4-HB cycle only requires 5 ATP and % NADPH to fix three molecules of into glucose. The 3-HP/4-HB cycle's intermediates also directly feed into other critical metabolic pathways, making it a flexible tool for surviving in harsh environments.
Metabolic engineering
is a greenhouse gas that contributes to global warming. The use of metabolic pathways to fix atmospheric is being evaluated to address climate change. The 3-hydroxypropionate/4-hydroxybutyrate cycle is a proposed pathway to fix excess in the atmosphere.
References
Archaea biology
Biochemical reactions | 3-Hydroxypropionate/4-hydroxybutyrate cycle | [
"Chemistry",
"Biology"
] | 840 | [
"Biochemistry",
"Archaea biology",
"Archaea",
"Biochemical reactions"
] |
78,087,656 | https://en.wikipedia.org/wiki/UY%20Centauri | UY Centauri is a variable star in the southern constellation of Centaurus. It ranges from an apparent visual magnitude of 6.93 down to 9.48 with a period of 178.4 days, making it too faint to readily view with the naked eye even at peak brightness. The distance to this star is approximately 2,160 light years based on parallax measurements, although it is drifting closer to the Sun with a radial velocity of −20 km/s.
In 1911, it was announced that Williamina Fleming had discovered the variability and peculiar spectrum of this star, then known as DM −44° 8539. It was given its variable star designation, UY Centauri, in 1912. In 1952, S. Gaposchkin listed it as a semiregular variable with a period of 114.6 days and a class of K5p. K. G. Henize included it in a list of candidate S stars below declination −25°, although noting it showed unusual spectral features. In 1971, UY Cen was named the prototype of SC stars, a rare group with spectra that lie between S- and C-type stars.
This is an evolved star on the asymptotic giant branch that is shedding mass at an estimated rate of ·yr−1. The ratio of carbon to oxygen isotopes in the stellar atmosphere is almost exactly 1. At this stage, it is expected that most of these expelled atoms become locked up in carbon monoxide gas, preventing further dust formation. However, in 2002, this star was observed to undergo a steep decline in luminosity, dropping by two magnitudes. This was interpreted as an episode of circumstellar dust formation. It may be an indication that UY Cen is starting to evolve away from the SC phase.
References
Carbon stars
S-type stars
Asymptotic-giant-branch stars
Semiregular variable stars
Centaurus
Durchmusterung objects
115236
064778
Objects with variable star designations | UY Centauri | [
"Astronomy"
] | 417 | [
"Centaurus",
"Constellations"
] |
78,087,909 | https://en.wikipedia.org/wiki/Lin-14 | LIN-14 is a nuclear protein that plays a crucial role in regulating developmental timing in the nematode worm Caenorhabditis elegans. It functions as a heterochronic gene, controlling the timing of developmental events during larval development. LIN-14 protein levels are high at the beginning of the first larval stage (L1) and then rapidly decline, which is essential for the transition from early to late cell fates. LIN-14 is a BEN domain transcription factor, capable of binding DNA and directly regulating gene expression. The protein's activity is tightly regulated by lin-4, a microRNA which inhibits LIN-14 protein synthesis through complementary base pairing with sequences in the lin-14 mRNA 3' untranslated region.
Regulation
The expression of the Lin-14 gene in Caenorhabditis elegans is tightly regulated by the Lin-4 gene through a microRNA-mediated mechanism. Lin-4 produces small RNAs that act as negative regulators of Lin-14 protein synthesis. These Lin-4 microRNAs bind to complementary sequences in the 3' untranslated region (UTR) of the Lin-14 mRNA, forming multiple RNA duplexes. This interaction leads to a post-transcriptional regulation of Lin-14 translation, resulting in a decrease over time of LIN-14 protein levels starting in the first larval stage (L1).
Nobel Prize
This work on microRNA-mediated gene regulation, including the discovery of the Lin-4/Lin-14 regulatory mechanism, was recognized with the 2024 Nobel Prize in Physiology or Medicine, awarded to Victor Ambros and Gary Ruvkun "...for the discovery of microRNA and its role in post-transcriptional gene regulation." Their work on the lin-4 microRNA and its regulation of the Lin-14 protein dates back to the late 1980s and early 1990s.
References
Caenorhabditis elegans | Lin-14 | [
"Chemistry"
] | 403 | [
"Biochemistry stubs",
"Protein stubs"
] |
78,087,980 | https://en.wikipedia.org/wiki/DopAmide | DopAmide, or L-DopAmide, is a synthetic levodopa (L-DOPA) analogue that can serve as a levodopa and dopamine prodrug and is of potential interest in the treatment of Parkinson's disease. DopAmide has an amide rather than the carboxyl group of L-DOPA, which imparts greater water solubility. The amide is hydrolyzed back to the acid by aminopeptidase enzymes.
See also
DA-Phen
Foslevodopa
Melevodopa
Etilevodopa
O,O′-Diacetyldopamine
O,O′-Dipivaloyldopamine
Neurotransmitter prodrug
References
Antiparkinsonian agents
Catecholamines
Dopamine agonists
Experimental drugs
Monoamine precursors
Prodrugs
Amides | DopAmide | [
"Chemistry"
] | 185 | [
"Chemicals in medicine",
"Amides",
"Functional groups",
"Prodrugs"
] |
78,088,031 | https://en.wikipedia.org/wiki/Antarctic%20high | In meteorology, the Antarctic High is the stronger of the two polar highs, areas of high atmospheric pressure situated in the poles. It is situated over Eastern Antarctica, hence it sometimes being referred to as the East Antarctic High.
Effects
Since the Last Glacial Period, temperature trends have suggested that the interplay from the Antarctic High and Southern Annular Mode has played a significant role in katabatic winds over the Patriot Hills Base Camp. A 2022 study by Nature noted that when the high is over the Drake Passage, it alongside an elongated cyclone located in the South Pacific transport warm and moist air to the southwestern Antarctic Peninsula, which is linked to record-high temperatures, extreme summertime melt, and dramatic break-ups in the Larsen Ice Shelf and eastern Antarctic Peninsula since the 1990s.
References
Regional climate effects
Environment of Antarctica
Meteorological phenomena | Antarctic high | [
"Physics"
] | 167 | [
"Meteorological phenomena",
"Physical phenomena",
"Earth phenomena"
] |
78,088,138 | https://en.wikipedia.org/wiki/Last%20Call%20BBS | Last Call BBS is a puzzle video game developed by Zachtronics. Released on August 4, 2022, it was the studio's final game before its closure.
Gameplay
Set on a Z5 Powerlance, a fictional 1990s PC, Last Call BBS features eight small puzzle games with distinct gameplay. To install the games, the player needs to dial an in-game BBS. All games contain elements of previous works developed by Zachtronics. For instance, 20th Century Food Court, a factory simulation game where the player arranges machines to make food, incorporates the assembly line elements of SpaceChem. With point-and-click controls, the games begin with easy introductory levels, before increasing in difficulty as new gameplay elements are introduced. In addition to the puzzle games, the game contains a circuit creation game, model-building simulator and a retro-style minigame of solitaire, similar to those present in previous Zachtronics games.
Development and release
The closure of Zachtronics was announced in June 2022, along with the announcements of Last Call BBS and a compilation of all solitaire minigames in the studio's previous works. Last Call BBS''' official trailer was released online later that month. The game was released on Steam via early access on July 5, and its final version was released on August 4. In an interview with Kotaku, Zach Barth, Zachtronics' founder and lead designer, said that the reason for their breakup was that they "felt it was time for a change." The team officially disbanded following the release of The Zachtronics Solitaire Collection, though some of its members, including Barth, are still active in game development. Last Call BBS'' received favorable reviews from critics upon release.
References
External links
2022 video games
MacOS games
Puzzle video games
Single-player video games
Video games about computing
Video games developed in the United States
Windows games
Zachtronics games | Last Call BBS | [
"Technology"
] | 397 | [
"Works about computing",
"Video games about computing"
] |
78,088,417 | https://en.wikipedia.org/wiki/Nitralin | Nitralin is a selective pre-emergent dinitroaniline herbicide that is closely related to trifluralin, and released two years later in 1966. Today it is largely obsolete. It was used in the USA, France and Australia to control annual grasses and broad-leaved weeds, and was applied on vines, crops and turf.
American farmers used in 1974, though trifluralin still overshadowed it, with . A 1992 report mentions extensive use on potatoes, though Shell's "Planavin" trademark expired in 1989.
On ryegrass meristems, nitralin suppressed elongation and made the roots wider. After 1 hour, mitosis was reduced by 76%. Cell nuclei expanded, becoming polymorphic, and with increased ploidy levels. Other dinitroanilines have similar effects, except butralin.
Nitralin is not associated with lung cancer.
Planavin
Planavin 75 was sold commercially as a wettable powder containing 75% nitralin, applied at around 2 pounds per acre (2.25 kg/Ha), equivalent to 1.5 lbs/acre of pure nitralin. Shell sold technical grade nitralin at 94% purity for manufacturing purposes.
Environmental Behaviour
Soil-applied nitralin is involatile; its vapours were below the limit of detection. Water leaching is very slow. Together this makes nitralin immobile in soil, so application can be precise, though it cannot move far enough into soil to control deep-germinating weed species. Typical in-soil halflives are 30 to 60 days, and it decomposes under ultraviolet light.
Metabolism
Ingested by rats, 98.5% is removed in 72 hours by urine and faeces. The metabolism is complex and produces many afterproducts.
Comparative Performance
Compared to trifluralin, nitralin is more toxic to the roots and less toxic to the shoots. Trifluralin prevented emergence of most species tested; nitralin did not prevent any from emerging. At Johnsongrass control, nitralin and pendimethalin lost out to trifluralin and other dinitroaniline herbicides.
Applications
References
External links
Anilines
Herbicides
Sulfones
Nitro compounds | Nitralin | [
"Chemistry",
"Biology"
] | 468 | [
"Sulfones",
"Biocides",
"Functional groups",
"Herbicides"
] |
78,088,544 | https://en.wikipedia.org/wiki/Fuel%20homogenizer | A fuel homogenizer is a mechanical device used to improve the quality and combustion efficiency of various fuels by reducing particle size and ensuring a uniform mixture. By applying mechanical shear forces, fuel homogenizers break down larger fuel droplets into smaller, more uniform sizes, promoting better atomization during combustion. This process can lead to optimized combustion, reduced sludge formation, lower emissions, and enhanced overall fuel efficiency. Fuel homogenizers are commonly utilized in industries such as maritime shipping, power generation, and petrochemical processing, particularly with heavy fuels like heavy fuel oil (HFO) and marine diesel oil (MDO). They are also increasingly applied to biofuels and fuel blends to prevent degradation and improve stability.
History
Fuel homogenizers were developed in the mid-20th century to address challenges associated with poor fuel quality, particularly in industries that relied on heavy fuel oil (HFO). Early models used mechanical seals to prevent leaks in high-pressure fuel systems and were primarily aimed at breaking down fuel particles and emulsifying water to improve combustion efficiency. Over time, technological advancements led to the introduction of magnetic couplings, which offered reduced wear, lower maintenance, and increased reliability compared to mechanical seals. The adoption of fuel homogenizers became more widespread as environmental regulations, such as MARPOL Annex VI, required industries to reduce emissions. Modern fuel homogenizers are now widely used to improve fuel quality and stability across a range of fuels, including biofuels and fuel blends, in industries such as maritime shipping and power generation.
Overview
Fuel homogenizers operate by applying mechanical shear forces to fuel, typically through a rotor-stator mechanism. This process reduces the size of larger fuel droplets, enhancing fuel atomization during injection in combustion engines. Improved atomization leads to more efficient combustion, less unburnt residue, and reduced emissions of nitrogen oxides (NOₓ), particulate matter (PM), and carbon dioxide (CO₂).
Installation and benefits
The benefits of fuel homogenizers vary depending on their placement within the fuel system:
Sludge reduction: When installed before fuel separators, fuel homogenizers can reduce sludge production by breaking down larger asphaltene clusters. This allows separators to remove impurities more efficiently. Studies have indicated that sludge reduction of up to 50–80% can be achieved with the use of homogenizers.
Combustion improvement: Installing homogenizers within the booster module, just before the automatic filter, enhances fuel atomization and combustion efficiency. This placement can lead to lower particulate emissions, reduced fuel consumption, and decreased CO₂ emissions.
Fuel homogenizers are also utilized to prevent fuel degradation when installed over fuel tanks. This application is particularly beneficial for biofuels, blends, and low-quality fuels, as the homogenizer helps maintain fuel stability by preventing stratification and ensuring consistent fuel flow.
Technology and functionality
The core technology of fuel homogenizers involves the application of mechanical shear forces to reduce fuel particle sizes to between 3 and 5 micron. This is typically achieved using a rotor-stator mechanism that subjects the fuel to intense shear forces, breaking down larger particles and clusters.
This process not only improves fuel atomization during combustion but also reduces the formation of sludge and carbon deposits within the engine. Additionally, homogenization can enhance water-in-fuel emulsions, where small amounts of water are mixed with fuel to lower combustion temperatures, thereby reducing NOₓ emissions.
Water-fuel emulsions
Water-fuel emulsions (WFE) are created by mixing water into the fuel to form a stable emulsion. This method is beneficial for reducing harmful emissions and improving combustion efficiency. The evaporation of water during combustion causes micro-explosions that further break down fuel droplets, resulting in finer atomization and more complete combustion.
Applications
Fuel homogenizers are employed in several industries:
Maritime shipping: In the maritime industry, homogenizers reduce sludge formation, improve engine efficiency, and assist vessels in complying with international emissions regulations such as MARPOL Annex VI. The reduction of CO₂ emissions through fuel savings is increasingly important due to regulations like the EU Emissions Trading System (EU ETS) and the FuelEU Maritime initiative, which aim to reduce greenhouse gas emissions from the maritime sector.
Power generation: Power plants that utilize heavy fuels benefit from improved fuel atomization and sludge reduction when using homogenizers, leading to enhanced combustion efficiency and reduced emissions.
Biofuels and blends: Homogenizers are critical in stabilizing biofuels and fuel blends, ensuring smooth engine operation and consistent fuel quality.
Environmental and economic benefits
The use of fuel homogenizers offers both environmental and economic advantages:
Reduction in emissions: By improving fuel atomization and combustion efficiency, homogenizers contribute to lower emissions of NOₓ, particulate matter, and carbon dioxide (CO₂). Improved combustion efficiency results in reduced fuel consumption, leading to lower CO₂ emissions per unit of energy produced.
Compliance with emission regulations: The reduction in CO₂ emissions is significant in the context of emission trading systems such as the European Union Emissions Trading System (EU ETS). Under the EU ETS and the upcoming FuelEU Maritime regulation, maritime operators are required to monitor, report, and reduce their greenhouse gas emissions. Fuel homogenizers can assist in achieving compliance by lowering CO₂ emissions through improved fuel efficiency.
Cost savings: Reduced sludge formation and improved combustion efficiency can lower fuel consumption and decrease costs associated with sludge disposal and emission allowances.
Extended equipment lifespan: Decreased sludge and carbon deposits allow for longer intervals between engine maintenance, reducing operational costs and extending the lifespan of equipment.
References
Fuel technology
Combustion
Mechanical engineering
Marine engineering
Environmental engineering | Fuel homogenizer | [
"Physics",
"Chemistry",
"Engineering"
] | 1,177 | [
"Applied and interdisciplinary physics",
"Chemical engineering",
"Environmental engineering",
"Combustion",
"Civil engineering",
"Mechanical engineering",
"Marine engineering"
] |
78,088,838 | https://en.wikipedia.org/wiki/Alarmo | The Nintendo Sound Clock: Alarmo is a digital alarm clock developed and produced by Nintendo. It was released exclusively at Nintendo stores and online for Nintendo Switch Online subscribers on October 10, 2024. A wide release of the device is set for March 2025.
Features
The device consists of a 2.8" LCD screen to display the time and other metrics, as well as a large light-up dial which can be used to navigate menus. As a ‘smart’ alarm clock it has a 2.4 GHz WiFi connectivity for firmware and content download. Unlike traditional alarm clocks, Alarmo uses a 24 GHz mmWave presence sensor to detect motion during sleep and waking up. The longer the user stays in bed without moving, the louder and more intense the sound of the alarm will become. Alarmo will play game sounds as the user starts to move around in bed, and will play a fanfare once they are out of bed completely. Additionally, the user can also view sleep records from the device and play ambient music at night while falling asleep.
Alarmo can be set to various game themes based on various Nintendo Switch titles, which will alter the display of the clock as well as the music and sounds that play. At launch, the clock contained themes for Super Mario Odyssey, The Legend of Zelda: Breath of the Wild, Splatoon 3, Pikmin 4, and Ring Fit Adventure. Each game theme contains seven alarms, for a total of 35 alarms pre-installed with the device. Further themes are planned to be added over time and can be installed wirelessly with a connected Nintendo account. A theme for Mario Kart 8 Deluxe was released in an update on December 10, 2024, and a theme for Animal Crossing: New Horizons is confirmed to be releasing in the future. Additionally, the clock displays a render of a character from a chosen theme beneath the current time which moves to the left or right of the display depending on detected movements.
Development
Nintendo first announced their intentions to create a sleep-tracking device during a financial briefing in 2014, which was intended to mark their entry into the "quality of life" market. The device, which would have used sensors to track a user's sleeping habits similarly to Alarmo, was being developed in partnership with health company ResMed but had been put on hold indefinitely in 2016.
Alarmo was developed in house by Nintendo's motion sensor research team. As the device's sensors could detect motion without the use of a camera, it was thought that the technology would be appropriate for use in a bedroom. Earlier prototypes of Alarmo lacked any design elements or sounds from other Nintendo properties. One such prototype used an LED dot-matrix display instead of a screen, however, the development team believed that it would be harder to use.
Release
The Alarmo was announced by Nintendo on October 9, 2024, and on the same day, it was released exclusively at Nintendo's official stores. It also became available to purchase online for Nintendo Switch Online subscribers. A wide release of the device is set for 2025. In Australia and New Zealand, a wide release is set for March 2025, and Nintendo Switch Online members can register for a chance to be able to pre-purchase the device early on November 13, 2024.
On October 10, 2024, Nintendo announced that, due to a large number of orders in Japan, they would no longer take new online orders in that region, and that the purchase method would be switching to a lottery-based system. The same day, the Alarmo was sold out at the Nintendo stores in New York City, Tokyo, Osaka, and Kyoto. One day later, Nintendo announced that the ability for Nintendo Switch Online members in Japan to register for a chance to purchase the device online, using the aforementioned lottery system, had begun.
2.0.0 Update
Nintendo released a major update for the Alarmo on October 9, 2024, the same date the device launched, bringing the version number to 2.0.0. It added new features, including Moderate Mode, and Movement records.
Reception
Early reactions to Alarmo found the alarm clock to be a surprising and unusual product for Nintendo to reveal, especially surrounding speculation about the announcement of the then-unannounced Nintendo Switch 2. Critics noted the expensive price point of Alarmo when compared to a traditional clock, as well as some limitations of the device including a lack of support for some bed sizes and multiple people or pets in one bed.
Nintendo Life awarded the device a 7/10, describing it as "a fun little device that's easy to use and will absolutely appeal to Nintendo fans both young and old if you value fun and whimsy over accuracy." They found the lack of an included AC adapter to be an inconvenience, noting that an adapter felt necessary for an alarm clock. They described the setup process as "very easy and very Nintendo, meaning there's a sliver of fun to be had in what is otherwise a straightforward affair". However, they recommended that if the Alarmo was being purchased for a young child, an adult should likely set up the device beforehand, stating that "there's nothing particularly difficult here, but you do need to understand what type of bed is in use (single, double, king, etc) along with where the Alarmo will be placed in relation to the bed itself". They praised the sound quality, saying, "[...] the volume isn't going to compete with the likes of an Alexa or a Bose speaker, but it does the job considering how close you're likely to be when sleeping. You can easily turn the volume up or down with the dial from the main screen, and the quality remains crisp and clear even at maximum." The Verge praised the design of the clock but criticized the motion-tracking technology's limited functionality and the sleep sounds only lasting 10 minutes, saying, "It’s first and foremost a $100 Nintendo-branded clock. It looks and sounds the part, which is to say, it’s incredibly charming and nostalgic. But if you’re looking for something to help you wake up better than a run-of-the-mill alarm or track your sleep more efficiently than an app on your phone, this isn’t it. Turns out, even adorable pikmin and inklings can’t change my mind about alarm clocks."
CNET’s Scott Stein gave it a mostly positive review, calling it “a novelty clock, a fun musical gift for the room of a kid or a Nintendo superfan”. “It’s absolutely charming and fine, but it’s not a drop-dead amazing thing either.” Scott added.
References
Nintendo hardware
Alarms
Products introduced in 2024
Clocks | Alarmo | [
"Physics",
"Technology",
"Engineering"
] | 1,385 | [
"Machines",
"Alarms",
"Clocks",
"Measuring instruments",
"Physical systems",
"Warning systems"
] |
78,088,911 | https://en.wikipedia.org/wiki/List%20of%20bi-metallic%20coins | List of Bi-Metallic coins minted since 1983
References
bi-metallic coins | List of bi-metallic coins | [
"Chemistry"
] | 17 | [
"Bi-metallic coins",
"Bimetal"
] |
78,089,027 | https://en.wikipedia.org/wiki/Alexei%20Koulakov | Alexei Koulakov is a theoretical physicist and a neuroscientist. He is the Charles Robertson Professor of Neuroscience at the Cold Spring Harbor Laboratory.
Koulakov's group has used mathematics and theoretical physics to explore the brain, with focus on neural computation, brain development, and the evolution of brain architecture for optimal function. He received the Sloan Fellowship in Theoretical Neuroscience from 1998 to 2001 and the NIH Director's Transformative Research Award in 2018.
Koulakov's research has been featured in media outlets, including Physics Today, Wired, Nautilus Magazine, Medical Xpress, Long Island Business News, and 'Scientific Inquirer''.
Education and early career
Koulakov earned an Engineer-physicist degree (equivalent to an MS) in Applied Mathematics and Physics from the Moscow Institute of Physics and Technology in 1990. From 1988 to 1993, he worked as an Engineer in the Theoretical Department at the Institute of Nuclear Energy in Troitsk, Moscow region. He then pursued a PhD in Theoretical Physics at the University of Minnesota, completing it in 1998. Following his doctoral studies, he engaged in a postdoctoral fellowship in Neuroscience in the Sloan Center for Theoretical Neurobiology at the Salk Institute for Biological Studies in La Jolla, California, where he conducted research from 1998 to 2001.
Career
Koulakov joined the Department of Physics at the University of Utah as an Assistant Professor in 2001. In 2003, he moved to Cold Spring Harbor Laboratory as an Assistant Professor, became an Associate Professor in 2008, and then was promoted to Professor in 2012. He held that role until 2021, when he became the Charles Robertson Professor.
Koulakov has served as the Director of the Swartz Center for Computational Neuroscience at Cold Spring Harbor Laboratory. He has organized workshops, including the Cosyne workshop in March 2018, which focused on exploring causal links between neural responses and behavior, and another, on computational olfaction, in March 2005 at Snowbird, Utah.
Research
Koulakov is most known for his contributions to condensed matter physics, computational neuroscience, brain evolution, neural development, olfactory coding, neural stem cells, machine learning, and artificial intelligence. He and his team have studied neural computation, brain development and evolution, including how neurons process information, how brain networks assemble during development, and how brain architecture evolved to facilitate its function.
Contributions to neuroscience
Computational principles of neural development
Koulakov and his colleagues developed a predictive quantitative model of neural development that integrated the effects of molecular guidance cues and activity-dependent neural plasticity (learning). This model explained the effects of genetic, surgical, and pharmacological manipulations on neural connectivity across species. Refined for the visual system, it predicted connectivity changes in genetically modified animals and was generalizable to other forms of connectivity.
Principles of cortical evolution
Koulakov's research has focused on quantitative models of brain evolution, including theoretical models of cortical maps, the development of cortical areas and their connectivity, and the influence of the genomic bottleneck on cortical network evolution.
Disposable neural stem cell hypothesis
Examining the decline in hippocampal neurogenesis with age, Koulakov's quantitative analysis revealed that this decline was due to the depletion of the neural stem cell pool, which occurred as these cells were activated to generate new neurons. Activated stem cells underwent asymmetric divisions to produce neurons and eventually matured into astrocytes. His team proposed a "disposable stem cell" model which explains the age-related decrease in stem cells as resulting from production of new neurons.
Olfactory coding
In collaboration with his colleagues, Koulakov devised theories for olfactory coding that helped build an understanding of olfactory information processing. These included theories for temporal processing in the early olfactory system, such as the primacy theory, structured connectivity theory, and sparse representations in the early olfactory system.
Decision making and meta-cognition
Koulakov's team has developed theories of decision-making in collaboration with experimental groups. They have formulated a theory of decision confidence that has been experimentally tested.
Reinforcement learning and motivated behavior
Koulakov and his colleagues established a deep neural network-based reinforcement learning model of motivational salience, allowing agents to quickly adapt their behavior to changing rewards based on dynamic needs. This approach improved the interpretability of behavioral data by inferring motivational dynamics in the brain. By linking sequential decision-making theories—including the marginal value theorem, reinforcement learning, and Bayesian methods—his research team proposed an optimal decision rule for stay-or-leave choices in natural environments.
Attractor dynamics is short- and long-term memory
Through joint efforts, Koulakov formulated theories of robust short-term (working) memory systems using attractor neural networks, and discovered that attractor states can be stabilized in networks exhibiting long-term synaptic plasticity, a phenomenon that may result from memory consolidation.
NeuroAI
Spanning 2019 to 2024, Koulakov worked at the intersection of neuroscience and AI, aiming to use insights from nervous system studies to develop improved AI algorithms.
Contributions to theoretical physics
Koulakov and his colleagues theoretically identified a new quantum state of electrons in quantum Hall samples under weak magnetic fields, resembling a liquid crystal phase, which they described as "Quantum Hall Nematics". This theoretical discovery was later confirmed experimentally. Within mesoscopic physics, they contributed to understanding the properties of small particles, such as quantum dots with a few electrons and superconducting vortex cores.
Awards and honors
2018 – NIH Director's Transformative Research Award, NIH
Selected articles
Koulakov, A. A., Fogler, M. M., & Shklovskii, B. I. (1996). Charge density wave in two-dimensional electron liquid in weak magnetic field. Physical review letters, 76(3), 499.
Fogler, M. M., Koulakov, A. A., & Shklovskii, B. I. (1996). Ground state of a two-dimensional electron liquid in a weak magnetic field. Physical Review B, 54(3), 1853.
Koulakov, A. A., Raghavachari, S., Kepecs, A., & Lisman, J. E. (2002). Model for a robust neural integrator. Nature neuroscience, 5(8), 775-782.
Chklovskii, D. B., & Koulakov, A. A. (2004). Maps in the brain: what can we learn from them?. Annu. Rev. Neurosci., 27(1), 369-392.
Encinas, J. M., Michurina, T. V., Peunova, N., Park, J. H., Tordo, J., Peterson, D. A., ... & Enikolopov, G. (2011). Division-coupled astrocytic differentiation and age-related depletion of neural stem cells in the adult hippocampus. Cell stem cell, 8(5), 566-579.
References
Theoretical physicists
Neuroscientists
Moscow Institute of Physics and Technology alumni
University of Minnesota alumni
Living people
Year of birth missing (living people) | Alexei Koulakov | [
"Physics"
] | 1,510 | [
"Theoretical physics",
"Theoretical physicists"
] |
78,091,678 | https://en.wikipedia.org/wiki/Ostrich%20oil | Ostrich oil is an oil derived from the fat of ostriches. Ostrich oil is composed of 36.51% of saturated fat, 46.75% of monounsaturated fat, and 18.24% of polyunsaturated fat. Ostrich oil contains fatty acids, such as omega-3, omega-6, and omega-9. It also contains vitamins and minerals like vitamin E and selenium, which serve as natural antioxidants. Emu oil in the USA has a similar composition to ostrich oil, but ostrich oil has a higher omega-3 content, containing 2.1% compared to 0.25% in emu oil.
Ostrich oil has antibacterial properties, and is used for various skincare purposes, such as inflammation reduction. Due to the moisturizing properties, ostrich oil is currently used in cosmetic formulations and food chemistry. Ostrich oil is also used in the food industry due to its containing of fatty acids and tocopherols, along with its low cholesterol content.
See also
Emu oil
Ostrich meat
Ostrich farming in North America
References
Ostriches
Oils
Ointments
Animal fat products
Dietary supplements | Ostrich oil | [
"Chemistry"
] | 260 | [
"Oils",
"Carbohydrates"
] |
78,092,513 | https://en.wikipedia.org/wiki/Digital%20signal%20processing%20and%20machine%20learning | Digital signal processing and machine learning are two technologies that are often combined.
Background
Digital signal processing
Digital signal processing (DSP) is the use of digital processing, such as by computers or more specialized digital signal processors, to perform a wide variety of signal processing operations. The digital signals processed in this manner are a sequence of numbers that represent samples of a continuous variable in a domain such as time, space, or frequency. In digital electronics, a digital signal is represented as a pulse train, which is typically generated by the switching of a transistor. Digital Signal Processing (DSP) has experienced considerable advancements over recent decades, largely due to innovations in digital computing and integrated circuit technology.
Approximately thirty years ago, digital computers and their hardware were typically large, expensive, and primarily utilized for general-purpose applications in scientific and business contexts, often without real-time processing capabilities. The progression from medium-scale integration (MSI) to large-scale integration (LSI) and eventually to very-large-scale integration (VLSI) has facilitated the development of smaller, faster, and more cost-effective digital computers, along with specialized DSP hardware. These advancements in digital circuits now enable the design of highly capable digital systems, allowing the execution of complex DSP tasks that were once impractical or prohibitively expensive to manage with analog systems.
Consequently, many signal processing tasks that were traditionally performed using analog methods are now efficiently handled by digital hardware, offering significant advantages in terms of cost, reliability, and flexibility. This transition from analog to digital processing has expanded the range of DSP applications and enhanced performance capabilities across various fields, including telecommunications, medical imaging, and audio processing.
Machine learning
Machine learning is a field of study in artificial intelligence concerned with the development and study of statistical algorithms that can learn from data and generalize to unseen data, and thus perform tasks without explicit instructions. Quick progress in the field of deep learning, beginning in 2010s, allowed neural networks to surpass many previous approaches in performance. Machine learning, a subfield of artificial intelligence (AI), enables computers and computer-controlled systems to perform tasks that require intelligent behavior, such as pattern recognition, data interpretation, and decision-making. It allows computers to address complex problems where establishing traditional, rule-based models would be inefficient or impractical.
Machine learning employs various techniques, including supervised, unsupervised, and reinforcement learning, to enable systems to learn from data and make predictions or classifications without being explicitly programmed with the models they aim to apply. Machine learning has gained widespread success and is now a fundamental component of numerous applications, including image recognition, natural language processing, autonomous systems, and predictive analytics. As a branch of computer science, it focuses on the development of algorithms that allow computers to identify patterns and understand data, mimicking certain aspects of human cognitive abilities. The adoption of machine learning has significantly expanded the capabilities of AI systems, contributing to its integration into a wide range of fields and technologies.
Applications
Digital Signal Processing (DSP) plays a crucial role across a wide range of applications:
Audio Processing: DSP is integral to modern audio technology, facilitating tasks such as music compression, equalization, noise suppression, echo cancellation, sound spatialization, and the application of various audio effects. It is widely used in devices such as mobile phones, smart speakers, headphones, and hearing aids.
Image Processing: DSP techniques are essential for image enhancement, restoration, compression, and segmentation. Applications include digital cameras, medical imaging, satellite image analysis, machine vision, and surveillance systems.
Speech Processing: DSP is fundamental to speech recognition, voice control, voice search, encoding and decoding, Voice over IP (VoIP), and speech enhancement. These technologies are found in mobile phones, smart assistants, hands-free devices, and hearing aids.
Communications: DSP is a cornerstone of modern digital communications, supporting key functions such as encoding, modulation/demodulation, equalization, error control, multiple access, and synchronization. It is widely applied in modems, cellular networks, wireless communications, radio, and broadband systems.
Sensors and Control: DSP enables advanced capabilities in sensor fusion and calibration, sensor linearization, motor control, and adaptive control systems. It is critical in automation, stability control, and Internet of Things (IoT) devices, improving sensor data processing and enhancing the responsiveness of control systems.
Signal Detection and Tracking: DSP is central to radar and sonar technologies, assisting in the detection and tracking of moving targets, target classification, direction-of-arrival estimation, noise reduction, and moving target indication. It also plays a role in waveform design and imaging.
Video Processing: DSP is used in video decoding, interlaced-to-progressive conversion, image stabilization, noise reduction, and analytics such as motion detection, object tracking, and recognition. Applications include home theater systems, surveillance cameras, and security systems.
Software Defined Radio (SDR): DSP, in combination with analog-to-digital converter technology, is fundamental to Software Defined Radio (SDR) systems. In these systems, functions such as modulation, filtering, and multiple access are managed through software rather than hardware, providing flexibility and adaptability across various radio frequencies.
Applied machine learning for signal processing
The integration of machine learning (ML) with digital signal processing (DSP) has significantly advanced various fields, enhancing the ability to process and analyze complex data. In image and video processing, ML-DSP systems enable more accurate object detection, facial recognition, and semantic segmentation, providing deeper insights into visual content. These technologies are widely applied in areas such as autonomous vehicles, surveillance systems, and any context requiring sophisticated visual analysis.
In speech and natural language processing, the combination of ML and DSP has transformed applications such as speech recognition, language translation, and sentiment analysis. These systems are capable of accurately understanding and transcribing spoken language, which facilitates the development of virtual assistants, chatbots, and voice-controlled devices, improving user interaction across a variety of consumer applications.
In healthcare diagnostics, the integration of ML and DSP has improved the accuracy of disease detection, diagnosis, and patient monitoring. ML algorithms are employed to analyze medical images for abnormalities, aiding in early detection and personalized treatment planning, thereby enhancing patient outcomes.
The integration of ML and DSP also plays a critical role in wireless communications, where it optimizes system performance by adapting to changing channel conditions, reducing interference, and predicting network congestion. This results in improved data throughput and more reliable connectivity in diverse wireless environments, contributing to efficient network management.
In the financial sector, ML-DSP applications are used in financial analytics and algorithmic trading, where ML models analyze market data to forecast stock prices and identify trading opportunities. These capabilities support more informed investment decisions and optimized portfolio management.
In environmental monitoring, the integration of ML and DSP enables the processing of data from sensors and remote sensing devices to monitor air quality, detect natural disasters, develop climate models, and assess environmental changes. This contributes to timely responses to environmental issues and supports sustainability efforts across the globe.
Solving problems of signal processing with machine learning
In the field of digital signal processing (DSP), various challenges arise when analyzing and manipulating signals. One approach to addressing these challenges involves leveraging machine learning (ML). In this context, machine learning refers to the use of algorithms and statistical models to extract meaningful information from signals, enabling more accurate predictions and classifications.
Applications of machine learning in signal processing include:
Signal Sampling and Filtering: One critical application of ML in signal processing is in managing the complexities associated with signal sampling and filtering. Signal processing often requires extracting relevant information from signals while reducing noise, which can be challenging when signals undergo transformations. Machine learning techniques can assist by learning the inherent patterns and relationships within the signals. For instance, when dealing with a band-limited signal processed through an RC high-pass filter, selecting an optimal sampling frequency is essential but can be difficult. ML algorithms can analyze signal characteristics and filter behavior to determine the most appropriate sampling frequency. By training on datasets that include different sampling frequencies and their outcomes, ML models can identify patterns linking the signal, filter, and sampling frequency.
Signal Recovery in Communication Systems: Machine learning also plays a role in signal recovery, particularly in communication systems where the original signal must be recovered from a modulated signal with an unknown phase. ML algorithms can estimate the phase value and determine the minimal sampling rate needed for accurate signal recovery. By analyzing historical data, ML models generalize knowledge to solve such signal recovery challenges efficiently.
Mitigating Aliasing: Aliasing occurs when the sampling rate is insufficient to capture the details of a signal, leading to errors in signal reconstruction. Machine learning techniques can help identify the optimal sampling rate to prevent aliasing, ensuring accurate signal reproduction. ML models analyze the frequency content of a signal and recommend appropriate sampling frequencies, improving the quality of the processed signal.
In summary, the integration of machine learning with digital signal processing offers a robust solution to many challenges in signal analysis and manipulation. ML algorithms can address issues related to sampling, filtering, modulation, and aliasing by learning from data and identifying underlying patterns. This combination enhances the effectiveness of traditional signal processing methods and enables innovative applications in areas such as telecommunications, audio processing, and medical diagnostics. As technology continues to advance, the potential for machine learning to transform signal processing practices remains significant.
The benefits of machine learning in signal processing
The integration of machine learning and signal processing has become increasingly prevalent, significantly impacting various industries by enabling more accurate, efficient, and intelligent data analysis. This convergence provides numerous benefits that are reshaping the technological landscape.
One key advantage of combining signal processing with machine learning is the enhanced ability to extract meaningful information from complex signals. Traditional signal processing techniques may face limitations in revealing insights from intricate data streams. However, when augmented by machine learning algorithms, signal processing becomes more effective in deciphering complex signals with greater accuracy and efficiency. Machine learning models can detect patterns and features that are challenging to identify using conventional methods, leading to a more comprehensive understanding of the underlying data.
Challenges and future prospects
The integration of machine learning (ML) with digital signal processing (DSP) offers numerous opportunities for enhancing signal processing capabilities across various fields. However, this convergence also introduces several challenges, including the need for large training datasets, the risk of overfitting, and increased computational complexity. Addressing these challenges requires a strategic approach to data collection, model design, and optimization techniques.
References
Machine learning
Digital signal processing
Technology | Digital signal processing and machine learning | [
"Engineering"
] | 2,165 | [] |
78,092,819 | https://en.wikipedia.org/wiki/Paulo%20Artaxo | Paulo Eduardo Artaxo Netto is a Brazilian atmospheric physicist.
Early life and education
Born in São Paulo, Brazil, Artaxo pursued his undergraduate and graduate studies at the University of São Paulo, where he obtained both his MSc and PhD in Physics.
Academic and professional career
Artaxo has held postdoctoral positions at several institutions, including the University of Antwerp in Belgium, Lund University in Sweden, and the NASA Goddard Space Flight Center in the United States.
At USP, Artaxo leads a research group that has revealed how aerosol particles, emitted by both natural processes and human activities, are critical to cloud formation and, consequently, to the regional and global climate. His research on the Amazon has highlighted the region's vulnerability to climate change, especially regarding the potential feedback loops that could exacerbate global warming.
Awards and recognition
He was awarded the TWAS Prize in Earth Sciences in 2007 and has been recognized as one of the most influential researchers in his field by Clarivate Analytics multiple times.
References
Brazilian scientists
Environmental scientists
Atmospheric scientists
Year of birth missing (living people)
Living people | Paulo Artaxo | [
"Environmental_science"
] | 222 | [
"Environmental scientists"
] |
78,094,103 | https://en.wikipedia.org/wiki/NGC%201252 | NGC 1252 is a metal-poor, possible open cluster or open cluster remnant located in the constellation Horologium, containing around 20 stars. Discovered in 1834 by John Herschel, it was described by John Louis Emil Dreyer as an 8th-magnitude star surrounded by a group of 18 or 20 stars. Stars TW Horologii and HD 20286 were once considered to be part of NGC 1252, but this is now not likely.
Due to the nature of the object, it has been given different classifications: according to Bouchet & Thé (1983), it is an open cluster at around 500 million years old located away, with a diameter of , while Baumgardt (1998) found it to be an asterism. Pavani, Bica, and Dutra et al. (2001) put the age at 3 billion years old and distance at . It is also approximately below the galactic disc.
Two structures are located nearby: the Tucana-Horologium association and the Hyades Stream. This proximity is the cause of the debate over NGC 1252's nature.
Notes
References
1252
Horologium (constellation)
Astronomical objects discovered in 1834
Open clusters
Discoveries by John Herschel | NGC 1252 | [
"Astronomy"
] | 253 | [
"Constellations",
"Horologium (constellation)"
] |
78,094,325 | https://en.wikipedia.org/wiki/Tesla%20Robovan | The Tesla Robovan is an electric autonomous van planned for future development by Tesla. Announced in October 2024, the vehicle is being designed to carry up to 20 passengers.
History
Background
The Tesla Master Plan Part Deux, released in 2016, suggested the development of a "people-mover," and in 2022 Tesla CEO Elon Musk spoke of the development of a "highly configurable Robovan for people & cargo."
The future large vehicle was teased at Tesla's 2023 Investor Day in March 2023, and the Tesla Master Plan Part 3, released a month later, outlined the production of a commercial van as part of the two vehicles it was going to launch along with a robotaxi.
Announcement
A concept version of the autonomous electric Robovan was unveiled on 10 October 2024 at the "We, Robot" event at Warner Brothers Studio in Los Angeles, with a prototype driving up near the main stage, and 14 people exited the vehicle. The Cybercab and the first free-walking Optimus humanoid robots were the principal features of the event.
The Robovan can carry up to 20 passengers and also work separately as a cargo van. TechCrunch said the vehicle had a "retro-futuristic look" with no steering wheel. Tesla CEO Elon Musk said "We’re going to make this, and it’s going to look like that." The Robovan is intended to operate on the Tesla Network, Tesla's ridehailing service for self-driving vehicles.
No further production or cost details were released.
See also
Tesla Cybercab
References
Tesla vehicles
Battery electric vehicles
Self-driving cars
Unreleased products
Concept cars
Electric vans
Taxi vehicles | Tesla Robovan | [
"Engineering"
] | 348 | [
"Automotive engineering",
"Self-driving cars"
] |
78,094,742 | https://en.wikipedia.org/wiki/Methenamine | Methenamine, also known as hexamine or hexamethylenetetramine and sold under the brand names Hiprex, Urex, and Urotropin among others, is a urinary tract antiseptic and antibacterial medication which is used in the prevention of recurrent urinary tract infections (UTIs). It is not an antibiotic, and unlike antibiotics, has no risk of bacterial resistance. Methenamine can reduce the risk of UTIs by 44 to 86% and has been found to be non-inferior to low-dose prophylactic antibiotics. It is taken by mouth. The drug is available both by prescription and at lower doses over the counter. Besides for UTI prevention, methenamine is also available in a topical form to treat hyperhidrosis.
Side effects of methenamine are generally minor and include upset stomach, nausea, and headache, among others. Methenamine is a prodrug of formaldehyde in acidic urine. Formaldehyde is a non-specific antiseptic and bactericide which works via denaturation of bacterial proteins and nucleic acids. Conversion of methenamine into formaldehyde only occurs in acidic environments and hence its actions show selectivity for tissues like the bladder and stomach. Chemically, methenamine is a simple cyclized hydrocarbon and is similar in structure to adamantane.
Methenamine was discovered in 1859 and was first introduced for medical use as a urinary antiseptic in 1895. It was formally approved for medical use in the United States in 1967. Though it became a "forgotten drug" following the discovery of antibiotics in 1928, there has been a resurgence in interest in methenamine since 2010 owing to increasing rates of bacterial resistance with antibiotics. Larger and higher-quality clinical trials of methenamine for UTI prevention have started to be published in the 2020s and it may soon be recommended by more medical guidelines. Methenamine has been found to be more cost-effective than low-dose prophylactic antibiotics for preventing UTIs.
Medical uses
Urinary tract infections
Methenamine is used in the treatment and prevention of recurrent urinary tract infections (UTIs) requiring long-term therapy. It is approved and used in both adults and children at least 6years of age. The drug can also be used in special populations including older adults, people undergoing genitourinary surgical procedures, people with long-term catheterization, and kidney transplant recipients. It has not been studied in neonates or infants. Methenamine is employed as an alternative to antibiotics. The drug is not used in the curative treatment of UTIs and should be started only after bacterial eradication by appropriate antimicrobial agents. As it is an antiseptic and not an antibiotic, methenamine has no risk of promoting bacterial resistance. Studies have administered continuous methenamine therapy usually for 12months or less, but in some studies for as long as 2 to 10years.
A 2012 Cochrane review found that methenamine was effective in the prevention of UTIs. The relative risk of symptomatic UTI was 0.24 and of bacteriuria was 0.56. In the case of short-term treatment (≤1week), the relative risk of symptomatic UTI was 0.14. On the other hand, methenamine was not effective in reducing the risk of symptomatic UTI or bacteriuria in people with known renal tract abnormalities or neurogenic bladder. The quality of evidence was mixed and often poor.
A subsequent large randomized controlled trial (RCT), the "ALternatives To prophylactic Antibiotics for the treatment of Recurrent urinary tract infection in women" (ALTAR) trial, was conducted by the United Kingdom National Health Service (NHS). This study, published in 2022, reported that methenamine (hippurate) was non-inferior to daily low-dose antibiotics for prevention of UTIs. The antibiotics used in the study included nitrofurantoin, trimethoprim, and cephalexin. There was a small and non-significant numerical advantage of antibiotics over methenamine in this trial (~0.5 fewer UTIs per year), but this difference was deemed of limited clinical consequence and was considered to be outweighed by the advantages of methenamine. UTI-free rates over 12months were 43% with methenamine and 54% with antibiotics. Besides effectiveness in terms of UTI prevention, methenamine demonstrated lower rates of bacterial resistance relative to antibiotic therapy in this trial and in other studies.
A 2024 systematic review found that methenamine was non-inferior to antibiotic prophylaxis in the prevention of UTIs in two comparative prospective clinical studies, including the ALTAR trial. Other, older studies found that methenamine was inferior to antibiotics including trimethoprim/sulfamethoxazole, trimethoprim, and nitrofurantoin in preventing or suppressing current UTIs, but these studies were of lower quality. Additional large and high-quality clinical trials of methenamine for UTI prevention are needed as of 2024. More studies are also needed in special populations like older adults. Another large RCT of methenamine for UTI prevention, the international European ImpresU trial in older women, which is comparing methenamine to placebo instead of against antibiotics, is underway as of 2022.
Methenamine is not widely recommended by medical guidelines for UTI prevention as of 2022. However, this is expected to change in the near future due to the publication of the ALTAR trial and other new high-quality clinical trials.
In addition to prescription methenamine, a lower-dose combination formulation of methenamine with the nonsteroidal anti-inflammatory drug (NSAID) sodium salicylate is available over-the-counter under brand names like Cystex for treatment and prevention of UTI symptoms. This formulation is much less-studied than prescription methenamine and little data are available to inform its use.
Methenamine is provided mainly as methenamine hippurate (the hippuric acid salt) or methenamine mandelate (the mandelic acid salt). The drug is taken twice daily in the case of methenamine hippurate and four times daily in the case of methenamine mandelate. Methenamine hippurate is more popular and commonly used owing to its more convenient dosing schedule. Methenamine is taken three times daily in the case of formulations in which low-dose methenamine free base is combined with sodium salicylate. The dosing schedule of methenamine is less convenient than once-daily low-dose prophylactic antibiotics.
Other genitourinary infections
Methenamine is converted into formaldehyde only in acidic environments like the urinary bladder and hence is not expected to be effective in the eradicative treatment of pyelonephritis (kidney infection) or chronic bacterial prostatitis. As a result, it is not recommended for such indications. However, methenamine may help to prevent pyelonephritis and hospitalization by preventing UTIs that can lead to these complications. In addition, in men with persistent or recurring chronic bacterial prostatitis, prophylactic methenamine may be useful as an alternative to low-dose prophylactic antibiotics in preventing prostatitis-derived UTIs and managing associated symptoms. Prophylactic low-dose methenamine combined with an ascorbic acid (vitamin C) supplement has been reported to be effective for this purpose based on clinical experience. In any case, supporting data for this use are lacking as of 2020.
Excessive sweating
Methenamine, in a topical cream or gel stick formulation sold under brand names like Antihydral and Dehydral, is used in the treatment of hyperhidrosis (excessive sweating) and has been reported to be clinically effective for this indication. The skin is slightly acidic and formaldehyde can be released from methenamine in this environment.
Available forms
Methenamine is provided in the form of 500 and 1,000mg oral tablets. It is available both alone and in combination with the nonsteroidal anti-inflammatory drug (NSAID) sodium salicylate. Other combinations with other drugs, such as phenazopyridine, are also available.
Methenamine is provided pharmaceutically alone as the hippuric acid (methenamine hippurate) and mandelic acid (methenamine mandelate) salts. The free base and other salts, including anhydromethylencitrate and sulfosalicylate, have also been marketed in some countries. Methenamine mandelate is provided as an enteric coated tablet and is taken four times daily, whereas methenamine hippurate is available only in non-coated tablet form and is taken twice daily. Non-coated methenamine tablets can have a chemical taste described as sweet, sour, and/or metallic.
Methenamine is available both by prescription (by itself) and over the counter (in combinations). Over-the-counter formulations in combination with sodium salicylate (162.5mg) contain a lower amount of methenamine of 162mg methenamine free base per tablet compared to prescription formulations and are taken three times daily.
Contraindications
The safety of methenamine in people with renal impairment is unknown and it is considered to be contraindicated in this context. Other contraindications include severe liver disease or hepatic impairment, known hypersensitivity to methenamine or the drug formulation's components, severe dehydration, hyperphosphatemia, and use of sulfonamides. Caution is also advised in people with gout. Its safety during pregnancy is unclear and it is known to enter the placenta, amniotic fluid, and breast milk. As such, discontinuation of methenamine is recommended during breastfeeding. No teratogenic effects with methenamine in animals have been observed. Although the preceding contraindications of methenamine have been specified, they are not well-defined and may not be absolute contraindications in all cases.
Side effects
Side effects of methenamine are minor and infrequent, reportedly occurring in fewer than 4% of individuals. They include dyspepsia (upset stomach), abdominal pain, dysuria (painful or uncomfortable urination), nausea, vomiting, diarrhea, headache, rash, and pruritus (itching). The drug is generally very well-tolerated. Rarely, reversibly elevated liver enzymes, including of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), have been reported. Normalization of liver enzymes has occurred with discontinuation or continuation of methenamine. Hypersensitivity reactions have also rarely been reported. It has been said that methenamine, overall, is very safe.
Formaldehyde is a known carcinogen, for instance being associated with nasopharyngeal cancer and leukemia. This compound also occurs in small amounts as a contaminant in alcoholic beverages, and is chemically similar to the carcinogenic ethanol (alcohol) metabolite acetaldehyde. Because of the formaldehyde exposure with methenamine, there have been concerns about methenamine's potential carcinogenicity and the possibility that it might increase the risk of cancer, for instance bladder or stomach cancer. No clinical studies have looked directly at the long-term effects of methenamine in this regard. However, there are no published case reports documenting incidence of cancer with methenamine as of 2023. Moreover, animal studies have found no evidence of long-term carcinogenicity with oral methenamine. On the other hand, the findings of animal studies of methenamine and carcinogenicity have also been questioned by some authors, though this topic is controversial.
Antibiotics are known to disrupt the gut, urinary tract, and vaginal microbiota. This has been associated with increased risk of recurrent UTIs. Methenamine has been limitedly studied in this regard, but was found in one small study to preserve urinary microbial diversity. However, more studies are needed to assess the influence of methenamine on the host microbiome, both in the urinary tract and elsewhere in the body.
Side effects of the topical form of methenamine for hyperhidrosis include dry skin, among others.
Overdose
Doses of methenamine much higher than usual have been clinically studied and found to produce significant toxicity. More specifically, doses of 8g per day (4–8-fold usual doses) for 3 to 4weeks resulted in bladder irritation, painful and frequent urination, albuminuria (albumin in urine), crystalluria (crystals in urine), and hematuria (blood in urine). Some of these side effects are thought to be due to high levels of formaldehyde in the bladder and consequent irritation. Doses of methenamine of up to 10 to 20g/day have also been studied and found to be tolerable without major toxicity. When methenamine was first introduced in the late 1800s and early 1900s, doses of 15 to 30g per day were commonly employed and doses of up to 60 to 180g per day were tried in some cases. Toxic effects of such high doses included urinary tract and bladder irritation, frequent urination, strangury, and hematuria. Animal studies employing double the modern human dosage of methenamine for 6 to 12months found no adverse effects.
Interactions
Concomitant use of methenamine and sulfonamides can result in insoluble methenamine salts precipitating in urine and hence is not recommended. Urinary alkalinizing agents, such as antacids, carbonic anhydrase inhibitors, and certain foods, may diminish the effectiveness of methenamine by making the urine more alkaline and thereby preventing the hydrolysis of methenamine into formaldehyde. Conversely, urinary acidifying agents, like ascorbic acid (vitamin C), sodium acid phosphate, and ammonium chloride, may enhance the effectiveness of methenamine by making the urine more acidic and thereby facilitating its hydrolysis into formaldehyde. Formaldehyde has been found in vitro to react with hydrochloric acid to form the highly carcinogenic compound bis(chloromethyl) ether and it may be conceivable that this might likewise occur in the stomach.
Pharmacology
Pharmacodynamics
Methenamine has non-specific antiseptic and antibacterial properties in acidic environments via hydrolysis into formaldehyde. Formaldehyde is an aldehyde and is highly reactive and thereby bactericidal. It acts by binding to and denaturing bacterial proteins and nucleic acids. Methenamine is almost completely inactive as an antibacterial in alkaline environments, in which it is not degraded into formaldehyde.
The drug's spectrum of antibacterial activity includes all urinary tract pathogens. It is specifically effective against common UTI-causing bacteria including Staphylococcus saprophyticus, Escherichia coli, Enterococcus faecalis, and Enterococcus faecium. However, Klebsiella aerogenes (Enterobacter aerogenes) has been said to generally be resistant to methenamine, although the mechanism and rationale supporting this resistance have not been described. In addition, certain urea-splitting bacteria, such as Proteus and Pseudomonas species, can make the urine more alkaline, thereby potentially inhibiting the antibacterial effects of methenamine. Providencia and Morganella species are also urea-splitting and might likewise be resistant to methenamine, although this topic requires more research.
Methenamine is provided medically as the hippuric acid or mandelic acid salt, and the acid salt component plays a key role in helping to make the urine more acidic such that the activity of methenamine is optimized. Ascorbic acid (vitamin C), sodium acid phosphate, or ammonium chloride can also be supplemented to further acidify the urine. However, it is unclear whether this actually improves treatment effectiveness or not.
Pharmacokinetics
Absorption
Methenamine is rapidly absorbed from the gastrointestinal tract with oral administration. Its oral bioavailability is high (≥70%).
Distribution
The drug is distributed widely throughout the body, including in saliva, bile, cerebrospinal fluid, synovial fluids, and pleural effusions. In accordance with its presence in cerebrospinal fluid, methenamine is known to cross the blood–brain barrier and enter the central nervous system. The volume of distribution and plasma protein binding of methenamine are unknown.
Metabolism
In terms of metabolism, methenamine is hydrolyzed to form formaldehyde and ammonium in acidic urine (pH < 6). More specifically, a single molecule of methenamine decomposes into six equivalents of formaldehyde and four ammonia molecules. The drug may be degraded 10 to 30% in the acidic environment of the stomach prior to absorption. This can be avoided with enteric coated tablets. In terms of pH, there is minimal hydrolysis at a pH of 7.4, 6% at a pH of 6, and 20% at a pH of 5. The hydrolysis of methenamine occurs slowly and gradually, with approximately 3hours required for 90% decomposition into formaldehyde. As breakdown of methenamine only occurs in acidic environments like the bladder and stomach, the activation of methenamine into formaldehyde in the body is tissue-selective. Following its formation, formaldehyde is rapidly metabolized into formic acid (formate) in the body.
Elimination
The drug is eliminated mainly by the kidneys. A single oral dose of methenamine is excreted 70 to 90% in urine unchanged within 24hours. The onset of action of the urinary antibacterial effects of methenamine is within 30minutes. A urinary formaldehyde concentration of 18 to 60μg/mL can be achieved with a typical therapeutic dosage of methenamine and these concentrations of formaldehyde can inhibit almost all urinary pathogens. The elimination half-life of methenamine is 2 to 6hours.
Chemistry
Methenamine, also known as 1,3,5,7-tetraazaadamantane, is a simple cyclic hydrocarbon with a cage-like structure and is similar in structure to adamantane (tricyclo[3.3.1.13,7]decane). It is specifically the analogue of adamantane in which the carbon atoms at the 1, 3, 4, and 7 positions have been replaced with nitrogen atoms. The drug is a white or colorless and odorless crystalline compound with a sweet, sour, and/or metallic taste. It is a hydrophilic compound with a predicted log P (XLogP3) of 0.3. Methenamine is usually provided medically as the hippuric acid or mandelic acid salt. Methenamine is the cation and hippuric acid or mandelic acid is the anion.
History
Methenamine was first discovered as a chemical compound in 1859. It was introduced for medical use as a urinary antiseptic under the name Urotropin in 1895. The drug was described as rapidly sterilizing and thereby restoring putrid and pus-filled urine to a normal appearance and constitution. A combination of methenamine with salicylic acid was also developed and introduced the same year. Methenamine was only used as a urinary antiseptic in cases of acidic urine, whereas boric acid was used to treat UTIs with alkaline urine. The drug name methenamine, a contraction of the chemical or scientific name hexamethylenetetramine, was formally introduced and designated by the United States Pharmacopeia (USP) by 1925 and replaced the prior name of the drug that was being used of hexamethylenamine. The alternative drug name hexamine was introduced in the British Pharmacopoeia (BP) by 1914 to be used instead of the commercial name Urotropin.
Interest in methenamine declined after the discovery of the antibiotic penicillin in 1928 and it has been described as a "forgotten drug". However, there was a surge of interest in methenamine from the 1950s to the 1980s. The drug was formally approved by the Food and Drug Administration (FDA) for medical use in the United States in 1967. The topical form of methenamine for treatment of hyperhidrosis was introduced around 1965.
Subsequently, there was another decline in interest in methenamine from 1980 until 2010.
However, there has been another resurgence in interest in methenamine for recurrent UTI prevention since 2010 owing to increasing rates of bacterial resistance with antibiotics. Larger and higher-quality clinical trials of methenamine for UTI prevention, such as the United Kingdom ALTAR trial, have started to be published in the 2020s, and additional trials, such as the international European ImpresU trial, are also underway as of 2024.
Society and culture
Names
Methenamine is the generic name of the drug and its , , and , while hexamine is its and . Brand names of methenamine include Aminoform, Antihydral, Dehydral, Formamine, Formin, Hexamine, Hiprex, Hyophen, Mandelamine, Metenamine, Phosphasal, Urelle, Urex, Uribel, Urimar, Urin DS, Urogesic Blue, Urotropin, and Ustell, among numerous others.
Availability
Methenamine is approved and available in the United States. Only methenamine hippurate, the twice-daily formulation, is available as a prescription drug in the United States. Of 38countries that were surveyed in one study, methenamine was available in seven of them. In any case, methenamine was marketed as a prescription drug widely throughout the world in 2004. The topical form of methenamine for hyperhidrosis has been marketed only in certain countries, including Austria, Canada, Germany, Luxembourg, and Switzerland.
Cost effectiveness
The costs of methenamine for long-term UTI prophylaxis can be significant. However, a 2024 study found that methenamine was more cost-effective than low-dose prophylactic antibiotics for prevention of UTIs.
Research
Methenamine might be useful in the treatment of Helicobacter pylori infections as it is activated in the acidic environment of the stomach.
The drug can safely be used intravenously and might be useful in the treatment of central nervous system infections as well as certain cancers.
See also
Methenamine/sodium salicylate
Uromune
References
Adamantane-like molecules
Antimicrobials
Antiseptics
Bactericides
Heterocyclic compounds with 3 rings
Nitrogen heterocycles
Prodrugs
Tertiary amines | Methenamine | [
"Chemistry",
"Biology"
] | 4,883 | [
"Antimicrobials",
"Prodrugs",
"Bactericides",
"Chemicals in medicine",
"Biocides"
] |
78,095,563 | https://en.wikipedia.org/wiki/RELHIC | A RELHIC, or Reionization-Limited HI Cloud, is a theoretical construct in astrophysics that describes a type of dark matter halo containing neutral hydrogen gas. These clouds are characterized by their potential to reveal the nature of dark matter and the conditions for galaxy formation in the early universe, particularly during the epoch of reionization. RELHICs are thought to be spherical gaseous systems that are in hydrostatic equilibrium and are influenced by both the presence of dark matter and a background ultraviolet radiation field from stars and galaxies.
The concept of RELHICs was proposed by astrophysicists Alejandro Benitez-Llambay and Julio F. Navarro, as part of their work on cosmological simulations and observations. They suggest that these structures could serve as observational targets to better understand the nature of dark matter and the formation of galaxies.
Recently, a RELHIC candidate, referred to as Cloud-9, was detected near the spiral galaxy Messier 94.
References
Dark matter | RELHIC | [
"Physics",
"Astronomy"
] | 203 | [
"Dark matter",
"Unsolved problems in astronomy",
"Concepts in astronomy",
"Unsolved problems in physics",
"Exotic matter",
"Physics beyond the Standard Model",
"Matter"
] |
78,095,765 | https://en.wikipedia.org/wiki/J1000%2B1242 | J1000+1242 known as SDSS J1000+1242 or J1000+12 is a radio-quiet type-2 quasar, located in the constellation Leo. It is located 2 billion light years from Earth and is classified as a Seyfert galaxy.
Characteristics
J1000+1242 has disturbed morphology indicating a galaxy merger. A tidal tail is clearly seen elongating away from the host galaxy towards south by 72 kiloparsecs (kpc), terminating at a location of a small source which implies a tidal dwarf galaxy.
Two unique nuclear emission sources are located in the galaxy. They have a projected separation of around 1.5 kpc indicating the merger resulted J1000+1242 having two active galactic nuclei (AGN) or from both sides of its narrow-line region concealed by a torus of gas and warm dust, or a circumnuclear ring. A bright emission line region is also found northeast of the nucleus of J1000+1242, with an irregular morphology indicating an outflowing bi-polar superbubble.
J1000+1242 has features of a typical AGN. This includes a radio core and hotspot. There is a presence of a deflected radio jet producing diffused lobes in both southeast and northwest directions. Not to mention, J1000+1242 has broad line regions producing emission lines with widths reaching to w80 of 850 km s−1. In both around and inside its radio lobes measuring ~ 10 kpc, J1000+1242 has five filamentary molecular gas structures. They seem to wrap around the radio lobes, which ~ 9 percent of the total molecular gas mass is found enclosed within these structures.
Star formation
J1000+1242 has an estimated star formation rate of 50 ± 10 Mʘ yr−1 with infrared luminosity deriving from its star formation in an 8-1000 ɥm range, of 45.0+0.1-0.2 erg s−1.
Black hole
The black hole in J1000+1242 is estimated to be 8.47 ± 0.76 Mʘ based on MBH-σ* relation.
References
External links
2MASX J10001317+1242261 on SIMBAD
Quasars
Galaxy mergers
J100013.14+124226.1
Leo (constellation)
1414663
F09575+1256
Seyfert galaxies
Active galaxies | J1000+1242 | [
"Astronomy"
] | 511 | [
"Leo (constellation)",
"Constellations"
] |
78,096,860 | https://en.wikipedia.org/wiki/Q1208%2B1011 | Q1208+1011 is a gravitationally-lensed quasar discovered in April 1986. It has a redshift of 3.80, and was the most distant astronomical object ever observed at the time of its discovery.
References
Astronomical objects discovered in 1986
Quasars | Q1208+1011 | [
"Astronomy"
] | 60 | [
"Virgo (constellation)",
"Constellations"
] |
78,097,592 | https://en.wikipedia.org/wiki/Culis%20monumentalibus | Culis monumentalibus (Latin for "monumental posterior") is an urban sculpture located on Pelayo street, in front of the Campoamor Theater, in the city of Oviedo, Principality of Asturias, Spain.
The sculpture, which bears the name in Latin and is made of bronze (the figure, which is four meters high) and granite (the pedestal, which is 80 centimeters high), is the work of Eduardo Úrculo, and is dated 2001.
See also
El Cul (A Santiago Roldán)
References
External links
lonelyplanet.com
forbes.com
2001 sculptures
Monuments and memorials in Oviedo | Culis monumentalibus | [
"Engineering"
] | 132 | [
"Architecture stubs",
"Architecture"
] |
78,097,982 | https://en.wikipedia.org/wiki/Erlianhyus | Erlianhyus is a genus of cetancodontamorph artiodactyl that lived during the Middle Eocene in China. It is monotypic and known from one species, E. primitivus.
Taxonomy
The holotype of Erlianhyus (IVPP V 28275) was discovered in strata from the Irdin Manha Formation. Its binomial name is derived from the Erlian Basin, in which it was discovered, and the suffix -hyus, which is often applied to bunodont artiodactyls. The species name, primitivus, refers to it bearing relatively primitive features. Erlianhyus was originally regarded as the sister taxon of a clade containing dichobunids, anthracotheriids and suoids. In 2023, Yu and colleagues performed a phylogenetic analysis that recovered it in a polytomy with Andrewsarchus and Achaenodon.
Description
Erlianhyus is known from a partial maxilla that preserves teeth P3–M3. The molars are bunodont and bear weak cristae, similar to entelodontids. Similarly M1 in both Erlianhyus and entelodonts lacks lingual cingulum. However, the molars have a large and lingually-positioned metaconule and the postmetaconule crista on M1 and M2 are distinct, suggesting that it does not belong to that clade.
References
Cetancodontamorpha
Eocene Artiodactyla
Eocene mammals of Asia
Fossil taxa described in 2021
Monotypic prehistoric Artiodactyla genera | Erlianhyus | [
"Biology"
] | 335 | [
"Phylogenetics",
"Cetancodontamorpha"
] |
78,098,289 | https://en.wikipedia.org/wiki/Rein%20Tamme | Rein Tamme (28 March 1940 – 8 October 2024) was an Estonian civil engineer and politician. A member of the Communist Party of the Soviet Union and subsequently the Estonian Centre Party and the Estonian Coalition Party, he served in the from 1990 to 1992.
Tamme died on 8 October 2024 at the age of 84.
References
1940 births
2024 deaths
People from Rakvere
Politicians from Lääne-Viru County
Civil engineers
20th-century Estonian politicians
Communist Party of Estonia politicians
Estonian Centre Party politicians
Estonian Coalition Party politicians
Voters of the Estonian restoration of Independence
Tallinn University of Technology alumni
Recipients of the Order of the National Coat of Arms, 3rd Class
Recipients of the Order of the National Coat of Arms, 4th Class | Rein Tamme | [
"Engineering"
] | 145 | [
"Civil engineering",
"Civil engineers"
] |
78,098,291 | https://en.wikipedia.org/wiki/Latin%20Americans%20Energy%20Organization | The Latin-American Energy Organization (OLADE) is a public international entity serving to manage and protect energy resources in South America and the Caribbean. OLADE is a mediator between Latin American countries and the Caribbean, encouraging cooperation and clear statistics of energy consumption. There are 27 participating member Latin American countries that confers with the OLADE.
Participating Latin - American Countries and the Caribbean
Argentina
Barbados
Belize
Bolivia
Brazil
Colombia
Costa Rica
Cuba, Chile
Ecuador
El Salvador
Grenada
Guatemala
Guyana
Haiti
Honduras
Jamaica
Mexico
Nicaragua
Panama
Paraguay
Peru
Dominican Republic
Suriname
Trinidad & Tobago
Uruguay
Venezuela
How a member state enters and leaves the OLADE
For a member state to official join OLADE is must fall under these criteria:
A sovereign and Independent state
Located in Latin American Territory
Agrees to fulfill all internal procedures and expenses to join
For a member state wishing to Leave OLADE they can do so at any time but still has rights and obligations to OLADE for thirty days. After which they are free to leave.
If a member state wishes to come back to OLADE it must be approved by the Meeting of Ministers and follow the regular requirements.
Establishment and Missions
The Latin Energy Organization was established in 1973 and it mission it to create an equal economic relationship between the developing countries and developed countries of Latin American and the Caribbean.
While also providing a platform for Latin American countries to speak on about energy, the organization also does acts of:
defending of natural resources
Addressing issues that rise within the energy market of good and demands
cooperating in creating sustainable and comprehensive polices
Governing Bodies
Within the Latin American Energy Organization, there are four governing bodies that manage the Organization.
Meeting of the Ministers:
The highest governing body in the OLADE. This governing body consists of a minister from each participating member state coming together to create a general policy. This policy must be in line with the Lima Agreement.
Council of Experts:
This is the advisory group of the Meeting of the Ministers. This governing body aims to provide advice and review of proposal to ministerial decision-making across the OLADE.
Directive committee (CODI):
The CODI is the check and balances governing body. This body main purpose is to observe and assess OLADE's policies, strategies, and programs.
Permanent Secretariat:
Position in OLADE which is responsible for implementing programs and policies.
OLADE assistance in agreement
The OLADE has greatly helped in some Latin American agreements, which includes:
Inter-American Development Bank - the Panama Agreement
Organization of the Petroleum Exporting countries (OPEC) - Guatemala Agreements
Binational agreement between Ecuador and Colombia
Current events
October 5, 2022:
Latin America Energy Organization and Global Energy Alliance for people and planet agreements in supporting sustainable transition to energy resources in Latin American and the Caribbean.
September 20, 2022:
International Atomic Energy Agency and Latin America Energy Organization agreements if exchanging on developments and energy power tools in the aim of transitioning to cleaner energy.
Current Executive Secretariat
The active executive secretariat of OLADE is Andrés Rebolledo Smitman. He is an economist graduating from the University of Chile and has served as a consultant to the International- American development bank (IDB).
Years in position
2023-2025
References
Wikipedia Student Program
Energy organizations | Latin Americans Energy Organization | [
"Engineering"
] | 640 | [
"Energy organizations"
] |
78,098,759 | https://en.wikipedia.org/wiki/Inger%20Thor%C3%A9n | Inger Arvidsdotter Thorén (née Bildt) (30 September 1913 – 18 November 1985), was a Swedish chemical engineer and food chemist. In 1938, she became the first woman assistant appointed at KTH Royal Institute of Technology.
Early life and education
Inger Bildt was born on 30 September 1913 in Sankt Matteus parish in Stockholm, the daughter of Signe Borg and bureau chief Arvid Bildt.
She graduated from the KTH Royal Institute of Technology as Master of Science in Engineering in chemical engineering in 1938, and was appointed as the first female assistant in the university after graduation.
After marriage in 1941, she was known as Inger Thorén.
Career
Thorén was an operations engineer at pharmacutical company Kabi in Hornsberg in Stockholm between 1940 and 1949 and a cereal chemist at the Kooperativa Förbundet Cooperative Association's bakery laboratory between 1953 and 1957.
She worked at Kvarnen Tre Kronor's development laboratory from 1957 until 1960, and then as product manager at Kungsörnen's development department from 1960 to 1970.
Thorén was active in the Swedish Association for Nutrition and held teaching posts at various university departments in the field.
In her development work as a food chemist, Thorén was interviewed regularly from the 1950s into the 1980s in both national and local newspapers. Pieces covered subjects including school bread, ideal flour, corn flakes, protein additives in flour, labelling for sell and use by dates when it was introduced, and preservatives. She also appeared on the TV programme Konsumentens brevlåda in 1964. She wrote articles for the magazine Livsmedelsteknik and contributed to teaching materials such as Bagerikemi (1956), Bättre brödsäd (1956) and Att baka bröd (1983).
After retirement, Thorén worked as a consultant and carried out studies for the Svensk spannmålshandel (Swedish Grain Trade) and the Brödinstitutet (Bread Institute) in Stockholm. She was a member of the Bildt Family Association and the Bildt Homestead Museum in Morlanda on Orust.
Personal life
Inger Thorén married the property manager Ernst Thorén (1913–1985) in 1941 and had three children with him, including veterinarian Kerstin Thorén Tolling.
Inger Thorén died on 18 November 1985 in Huddinge parish in Stockholm County.
References
1913 births
1985 deaths
20th-century Swedish engineers
Women engineers
People from Stockholm
Chemical engineering
Food engineers | Inger Thorén | [
"Chemistry",
"Engineering"
] | 522 | [
"Chemical engineering",
"Food engineers",
"Food engineering",
"nan"
] |
78,099,064 | https://en.wikipedia.org/wiki/El%20Cul%20%28A%20Santiago%20Rold%C3%A1n%29 | El Cul (A Santiago Roldán) is a monument unveiled in 1999, created by sculptor Eduardo Úrculo, situated in the Parque de Carlos I in Barcelona, Spain. It is a bronze sculpture with a height of , a tribute to Santiago Roldán, the president of the Holding Olímpico SA. In Oviedo, Eduardo Úrculo created a similar sculpture, Culis monumentalibus.
References
1999 sculptures
Monuments and memorials in Barcelona | El Cul (A Santiago Roldán) | [
"Engineering"
] | 97 | [
"Architecture stubs",
"Architecture"
] |
73,749,241 | https://en.wikipedia.org/wiki/PitchYaGame | PitchYaGame or #PitchYaGame (sometimes abbreviated to PYG) is a volunteer movement hosted on the social media platform Twitter to showcase, and present awards for, independent video games from around the world.
Description
PitchYaGame is hosted on the social media platform Twitter to showcase independent video games from around the world. Video pitches are presented by developers in June and November each year, and use the hashtag #PitchYaGame to identify and reference news about the showcase and the individual pitches, and the presentation of awards.
The showcase was founded in May 2020 by Liam Twose, with the mission of recognising independent video games, and "focused on empowering indie game developers to strengthen their position in the industry." Twose has made clear that PitchYaGame is a showcase and not a hardcore competition, with "[j]ust enough of a push to make sure people put their best pitch forward."
The team now comprises Twose (@LiamTwose at Twitter), operations manager "Indie Game Lover" (@IndieGameLover), and host Sarah Clancy (@ImSarahNow).
The pitches were originally made monthly, with entries split into a number of categories, but this proved unmanageable. PitchYaGame collaborator, Sarah Clancy reported that judging the many entries on a monthly basis was "difficult and unwieldy." Therefore, pitches were later switched to six monthly, "feature creep" was reduced, and awards streamlined into gold, silver, bronze, runners-up, and most viral.
Sponsorship
In June 2021, PitchYaGame prizes were sponsored by Xsolla, and in November 2021 by Aurora Punks and Cold Pixel. No cash prizes were available in 2022, as the organisers moved PitchYaGame into a less-competitive, "more showcase centric format".
Reception
In October 2020, Elijah Beahm at The Escapist wrote that "One of the greatest challenges for any game is landing a solid pitch. You have to sell people, maybe even a publisher, to take your idea seriously. Most of the time, it’s an obfuscated process that leaves the average developer scratching their heads, but Liam Twose and his team behind #PitchYaGame, 'PYG' for short, are looking to change all that with some clever social engineering."
In March 2021, Cameron Koch at GameSpot wrote that "Using the #PitchYaGame, thousands of indie developers tweeted out pitches for their games on November 2 as part of a social media contest, and the results are astounding." He went on to say that "There is no arguing with the results. According to Twose, around 1100-1300 games were shared with the hashtag, and some real gems look to have shined through."
In November 2021, Stafano "Stef" Castelli at IGN Italia wrote that "I myself enjoyed 'browsing through' the competitors, discovering a handful of intriguing video games in development." (translated from Italian).
In November 2022, Eric Bartelson at Premortem Games wrote that "It's a great way to get games noticed by fellow developers, but also publishers, investors and press."
In June 2023, Mark Plunkett in Kotaku wrote about the impossibility of keeping up with all the video game releases, and described PitchYaGame, which has attracted over 10,000 pitches since 2020, as an "astoundingly simple idea" that has "become an increasingly useful spot to catch up on some excellent-looking games that we may have otherwise completely slept on."
See also
Video game development
References
External links
PitchYaGame at YouTube
Video game events
Video game development competitions
Indie games
Social media
Entertainment events
Recurring events established in 2020
Semiannual events
Hashtags | PitchYaGame | [
"Technology"
] | 783 | [
"Computing and society",
"Social media"
] |
73,749,638 | https://en.wikipedia.org/wiki/Money%20gesture | The money gesture, also known as the pay me gesture, is signalled by repeatedly rubbing one's thumb over the tip of the index finger and middle finger. The gesture resembles the act of rubbing coins or bills together and is generally used to indicate financial topic.
Incidents
Starting in 2012, American football player Johnny Manziel used the gesture to celebrate touchdowns. It has been used in a similar way by football player T. J. Yeldon and academic R. Bowen Loftin. In 2015, Manziel stopped using the gesture after his opponents often responded in kind.
In 2022, British politician James Cleverly made the money gesture to Keir Starmer, the Leader of the Opposition. He allegedly alluded to suggestions claiming the Labour Party accepts donations from trade unions.
During the 2022 FIFA World Cup, an Ecuadorian fan used the gesture against Qatar, alluding to unfair refereeing.
In 2023, Slovenian basketball player Luka Dončić was fined $35,000 for using the money gesture. Dončić rubbed his fingers together signaling that the game officials had been paid off, and NBA found it "unprofessional and inappropriate".
See also
List of gestures
References
External links
Gestures | Money gesture | [
"Biology"
] | 245 | [
"Behavior",
"Gestures",
"Human behavior"
] |
73,751,330 | https://en.wikipedia.org/wiki/Efanesoctocog%20alfa | Efanesoctocog alfa, sold under the brand name Altuviiio, is a medication used for the treatment of hemophilia A (congenital factor VIII deficiency).
Efanesoctocog alfa was approved for medical use in the United States in February 2023.
Medical uses
Efanesoctocog alfa is a recombinant DNA-derived, Factor VIII concentrate indicated for use in adults and children with hemophilia A (congenital factor VIII deficiency) for routine prophylaxis to reduce the frequency of bleeding episodes; on-demand treatment & control of bleeding episodes; and perioperative management of bleeding.
Society and culture
Legal status
In April 2024, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Altuvoct, intended for the prevention and treatment of bleeding in people with hemophilia A caused by factor VIII deficiency. The applicant for this medicinal product is Swedish Orphan Biovitrum. Altuvoct was approved for medical use in the European Union in June 2024.
References
Antihemorrhagics
Orphan drugs
Recombinant proteins
Sanofi | Efanesoctocog alfa | [
"Biology"
] | 258 | [
"Recombinant proteins",
"Biotechnology products"
] |
73,752,273 | https://en.wikipedia.org/wiki/Teodor%20Gotszalk | Teodor Paweł Gotszalk is a Polish scientist who is head of Department of Nanometrology at Wrocław University of Science and Technology. Corresponding member of Polish Academy of Sciences since 2022. Teodor Gotszalk works in the area of nanotechnology and nanometrology, particularly scanning probe microscopy (SPM), scanning electron microscopy (SEM) and focused ion beam (FIB) techniques, and using microelectromechanical systems (MEMS).
Career
Teodor Gotszalk has been a Head of Department of Nanometrology at the Wrocław University of Science and Technology's Faculty of Microsystem Electronics and Photonics since 2006. Since then, he has been chairing the first Polish team focused on comprehensive metrology of micro- and nanostructures. The studies combine scanning probe microscopy, scanning electron microscopy and focused ion beam (SPM, SEM and FIB) techniques together with measurements of electrical, thermal, diffractive and optical properties of the structures.
Teodor Gotszalk has been a Corresponding member of the Polish Academy of Sciences since 2022.
Private life
Son of Krystyna and Ryszard Gotszalk. Husband of Magdalena Cisek-Gotszalk, father of Anna Kotowska.
Grants and awards
Awardee of the German Academic Exchange Service (DAAD) (30 months), Fulbright Program (4 months at the University at Albany, SUNY's College of Nanoscience and Engineering in 2010) and Kosciuszko Foundation (3 months at the University of California, Berkeley, 2022).
References
1966 births
Living people
21st-century Polish physicists
Nanotechnologists
Scientists from Wrocław
Academic staff of the Wrocław University of Science and Technology
Wrocław University of Technology alumni
Members of the Polish Academy of Sciences | Teodor Gotszalk | [
"Materials_science"
] | 382 | [
"Nanotechnology",
"Nanotechnologists"
] |
73,752,551 | https://en.wikipedia.org/wiki/Fundamental%20sequence%20%28set%20theory%29 | In set theory, a mathematical discipline, a fundamental sequence is a cofinal sequence of ordinals all below a given limit ordinal. Depending on author, fundamental sequences may be restricted to ω-sequences only or permit fundamental sequences of length . The element of the fundamental sequence of is commonly denoted , although it may be denoted or . Additionally, some authors may allow fundamental sequences to be defined on successor ordinals. The term dates back to (at the latest) Veblen's construction of normal functions , while the concept dates back to Hardy's 1904 attempt to construct a set of cardinality .
Definition
Given an ordinal , a fundamental sequence for is a sequence such that and . An additional restriction may be that the sequence of ordinals must be strictly increasing.
Examples
The following is a common assignment of fundamental sequences to all limit ordinals less than .
for limit ordinals
for .
This is very similar to the system used in the Wainer hierarchy.
Usage
Fundamental sequences arise in some settings of definitions of large countable ordinals, definitions of hierarchies of fast-growing functions, and proof theory. Bachmann defined a hierarchy of functions in 1950, providing a system of names for ordinals up to what is now known as the Bachmann–Howard ordinal, by defining fundamental sequences for namable ordinals below . This system was subsequently simplified by Feferman and Aczel to reduce the reliance on fundamental sequences.
The fast-growing hierarchy, Hardy hierarchy, and slow-growing hierarchy of functions are all defined via a chosen system of fundamental sequences up to a given ordinal. The fast-growing hierarchy is closely related to the Hardy hierarchy, which is used in proof theory along with the slow-growing hierarchy to majorize the provably computable functions of a given theory.
Additional conditions
A system of fundamental sequences up to is said to have the Bachmann property if for all ordinals in the domain of the system and for all , . If a system of fundamental sequences has the Bachmann property, all the functions in its associated fast-growing hierarchy are monotone, and eventually dominates when .
References
Set theory
Ordinal numbers | Fundamental sequence (set theory) | [
"Mathematics"
] | 450 | [
"Ordinal numbers",
"Set theory",
"Mathematical logic",
"Mathematical objects",
"Order theory",
"Numbers"
] |
73,752,688 | https://en.wikipedia.org/wiki/Protactinium%20trihydride | Protactinium trihydride is an inorganic compound with the chemical formula PaH. It is isostructural with uranium trihydride and can be prepared by reacting protactinium and hydrogen at 250°C and 600 mmHg. Theoretical calculations show that it can form further compounds PaH (n = 4, 5, 8, 9) under high pressure. Protactinium trihydride is sensitive to moist air and oxygen.
References
Protactinium compounds
Metal hydrides | Protactinium trihydride | [
"Chemistry"
] | 108 | [
"Metal hydrides",
"Inorganic compounds",
"Reducing agents"
] |
73,752,712 | https://en.wikipedia.org/wiki/Skiagraphia | Skiagraphia is a painting technique developed by Ancient Greek painter Apollodorus, used to create shadows in an image.
Skiagraphia is often described as a hatching technique used to create the illusion of forms through shading. The shading is created by the use of curved lines, either by the use of hatching or cross-hatching. Within this same approach, painters can use different colors to add shade to an area.
Archaeologist Eva Keuls, using passages from Aristotle, suggested that "skiagraphia" was a technique that utilized patches of color that blend from afar, similar to the neo-impressionist paintings of Georges Seurat, but this is disputed by Elizabeth G. Pemberton, who instead suggests that the passages from Aristotle are only in relation to shade and not color.
References
Ancient Greek painting
Painting techniques
Shadows
5th-century BC Greek art
5th-century BC beginnings | Skiagraphia | [
"Physics"
] | 185 | [
"Optical phenomena",
"Physical phenomena",
"Shadows"
] |
73,752,761 | https://en.wikipedia.org/wiki/Protactinium%20monoxide | Protactinium monoxide is a radioactive inorganic compound and one of the oxides of protactinium. Its chemical formula is PaO. It is a black solid that crystallizes in the rock-salt structure. Protactinium monoxide can be produced in minute quantities from the oxidation of protactinium.
The protactinium monoxide cation (PaO+) is very active and can activate hydrocarbons such as alkenes.
References
Oxides
Protactinium compounds | Protactinium monoxide | [
"Chemistry"
] | 106 | [
"Oxides",
"Salts"
] |
73,754,565 | https://en.wikipedia.org/wiki/Fossil%20history%20of%20flowering%20plants | The fossil history of flowering plants records the development of flowers and other distinctive structures of the angiosperms, now the dominant group of plants on land. The history is controversial as flowering plants appear in great diversity in the Cretaceous, with scanty and debatable records before that, creating a puzzle for evolutionary biologists that Charles Darwin named an "abominable mystery". Nonetheless, in April 2024, scientists reported an overview of the origin and development of flowering plants over the years based on extensive genetic studies.
Paleozoic
Fossilised spores suggest that land plants (embryophytes) have existed for at least 475 million years. Early land plants reproduced sexually with flagellated, swimming sperm, like the green algae from which they evolved. An adaptation to terrestrial life was the development of upright sporangia for dispersal by spores to new habitats. This feature is lacking in the descendants of their nearest algal relatives, the Charophycean green algae. A later terrestrial adaptation took place with retention of the delicate, avascular sexual stage, the gametophyte, within the tissues of the vascular sporophyte. This occurred by spore germination within sporangia rather than spore release, as in non-seed plants. A current example of how this might have happened can be seen in the precocious spore germination in Selaginella, the spike-moss. The result for the ancestors of angiosperms and gymnosperms was enclosing the female gamete in a case, the seed.
The first seed-bearing plants were gymnosperms, like the ginkgo, and conifers (such as pines and firs). These did not produce flowers. The pollen grains (male gametophytes) of Ginkgo and cycads produce a pair of flagellated, mobile sperm cells that "swim" down the developing pollen tube to the female and her eggs.
Angiosperms appear suddenly and in great diversity in the fossil record in the Early Cretaceous. This poses such a problem for the theory of gradual evolution that Charles Darwin called it an "abominable mystery". Several groups of extinct gymnosperms, in particular seed ferns, have been proposed as the ancestors of flowering plants, but there is no continuous fossil evidence showing how flowers evolved.
Several claims of pre-Cretaceous angiosperm fossils have been made, such as the upper Triassic Sanmiguelia lewisi, but none of these are widely accepted by paleobotanists. Oleanane, a secondary metabolite produced by many flowering plants, has been found in Permian deposits of that age together with fossils of gigantopterids. Gigantopterids are a group of extinct seed plants that share many morphological traits with flowering plants. Molecular evidence suggests that the ancestors of angiosperms diverged from the gymnosperms during the late Devonian, about 365 million years ago.
Triassic and Jurassic
Based on fossil evidence, some have proposed that the ancestors of the angiosperms diverged from an unknown group of gymnosperms in the Triassic period (245–202 million years ago). Fossil angiosperm-like pollen from the Middle Triassic (247.2–242.0 Ma) suggests an older date for their origin, which is further supported by genetic evidence of the ancestors of angiosperms diverging during the Devonian. A close relationship between angiosperms and gnetophytes, proposed on the basis of morphological evidence, has more recently been disputed on the basis of molecular evidence that suggest gnetophytes are instead more closely related to conifers and other gymnosperms.
The evolution of seed plants and later angiosperms appears to be the result of two distinct rounds of whole genome duplication events. These occurred at and . Another possible whole genome duplication event at perhaps created the ancestral line that led to all modern flowering plants. That event was studied by sequencing the genome of an ancient flowering plant, Amborella trichopoda.
Many paleobotanists consider the Caytoniales, a group of "seed ferns" that first appeared during the Triassic and went extinct in the Cretaceous, to be amongst the best candidates for a close relative of angiosperms. The fossil plant species Nanjinganthus dendrostyla from Early Jurassic China seems to share many exclusively angiosperm features, such as flower-like structures and a thickened receptacle with ovules, and thus might represent a crown-group or a stem-group angiosperm. Other researchers contend that the structures are misinterpreted decomposed conifer cones.
Cretaceous
Whereas the earth had previously been dominated by ferns and conifers, angiosperms quickly spread during the Cretaceous. They now comprise about 90% of all plant species including most food crops. It has been proposed that the swift rise of angiosperms to dominance was facilitated by a reduction in their genome size. During the early Cretaceous period, only angiosperms underwent rapid genome downsizing, while genome sizes of ferns and gymnosperms remained unchanged. Smaller genomes—and smaller nuclei—allow for faster rates of cell division and smaller cells. Thus, species with smaller genomes can pack more, smaller cells—in particular veins and stomata—into a given leaf volume. Genome downsizing therefore facilitated higher rates of leaf gas exchange (transpiration and photosynthesis) and faster rates of growth. This would have countered some of the negative physiological effects of genome duplications, facilitated increased uptake of carbon dioxide despite concurrent declines in atmospheric CO2 concentrations, and allowed the flowering plants to outcompete other land plants.
The oldest known fossils definitively attributable to angiosperms are reticulated monosulcate pollen from the late Valanginian (Early or Lower Cretaceous - 140 to 133 million years ago) of Italy and Israel, likely representing basal angiosperms.
The earliest known macrofossil confidently identified as an angiosperm, Archaefructus liaoningensis, is dated to about 125 million years BP (the Cretaceous period), whereas pollen considered to be of angiosperm origin takes the fossil record back to about 130 million years BP, with Montsechia representing the earliest flower at that time.
In 2013 flowers encased in amber were found and dated 100 million years before present. The amber had frozen the act of sexual reproduction in the process of taking place. Microscopic images showed tubes growing out of pollen and penetrating the flower's stigma. The pollen was sticky, suggesting it was carried by insects. In August 2017, scientists presented a detailed description and 3D model image of what the first flower possibly looked like, and suggested that it may have lived about 140 million years ago. A Bayesian analysis of 52 angiosperm taxa suggested that the crown group of angiosperms evolved between and .
DNA analysis showed that Amborella trichopoda, on the Pacific island of New Caledonia, belongs to a sister group of the other flowering plants, while morphological studies suggest that it has features that may have been characteristic of the earliest flowering plants. The orders Amborellales, Nymphaeales, and Austrobaileyales diverged as separate lineages from the remaining angiosperm clade at a very early stage in flowering plant evolution.
The great angiosperm radiation, when a great diversity of angiosperms appears in the fossil record, occurred in the mid-Cretaceous, approximately 100 million years ago. However, a study in 2007 estimated that the divergence of the five most recent of the eight main groups, namely the genus Ceratophyllum, the family Chloranthaceae, the eudicots, the magnoliids, and the monocots, occurred around 140 million years ago.
Island genetics offers a possible explanation for the sudden, fully developed appearance of flowering plants. It is believed to be a common source of speciation in general, especially when this is associated with radical adaptations that seem to have required transitional forms. Flowering plants may have evolved on an island or island chain, where the plants bearing them were able to develop a specialised relationship with a specific animal such as a wasp. Such a relationship, with a hypothetical wasp carrying pollen from one plant to another much as modern fig wasps do, could cause the requisite specialisation in both the plant and its partners. The wasp example is not incidental; bees, which evolved specifically due to mutualistic plant relationships, are descended from wasps. The paleontologist Robert T. Bakker has proposed that flowering plants might have evolved due to interactions with dinosaurs. He argued that herbivorous dinosaurs provided a selective grazing pressure on plants.
By the late Cretaceous, angiosperms appear to have dominated environments formerly occupied by ferns and cycadophytes. Large canopy-forming trees replaced conifers as the dominant trees close to the end of the Cretaceous, 66 million years ago or even later, at the beginning of the Paleogene. The radiation of herbaceous angiosperms occurred much later. Yet, many fossil plants recognisable as belonging to modern families (including beech, oak, maple, and magnolia) had already appeared by the late Cretaceous. Flowering plants appeared in Australia about 126 million years ago. This also pushed the age of ancient Australian vertebrates, in what was then a south polar continent, to 126–110 million years old.
References
Angiosperms
Fossil record of plants | Fossil history of flowering plants | [
"Biology"
] | 1,956 | [
"Plants",
"Angiosperms"
] |
73,754,985 | https://en.wikipedia.org/wiki/Mistral%20%28software%29 | Mistral is an information retrieval system designed and produced by the French company CII in the 1970s, which quickly became known internationally.
History
Mistral was created in 1970 to meet the needs of CNEXO (now IFREMER). This version was still rudimentary and was designed for a time when disk space was very expensive, and therefore used magnetic tapes and only sequential processing was allowed.
Subsequently, CII considered Mistral a flagship product for the Iris 80 and Iris 50 systems and maintained a strong development team. It was able to produce a series of versions which brought significant improvements, for example:
Transition from tape to magnetic disk
Thesaurus introduction,
Indexing of free-form text fields,
Interactive mode, first in transaction mode then in time-sharing.
In 1978, Mistral was chosen for the creation of a "national server center" (), .
After 1977, Mistral was ported to Honeywell GCOS7 and GCOS8.
Paradoxically, this success led to the gradual end of Mistral's life. Part of the initial team joined this new company. On the other hand, with the tribulations of CII, the support was more reduced. Finally, the use of this software by a documentation center seemed complex, and products that were less efficient but easier to access, and in particular Texto, multiplied.
Technical characteristics
Bibliographic file
Mistral manages bibliographic records which are stored in bibliographic files. Entries are stuructured as a set of fields which can be of three types:
reference — mandatory and unique, it contains a key allowing the record to be uniquely designated;
monovalued — field whose content is reduced to a single value (for example the title);
multivalued — field whose content consists of a list of values separated by a separator (configurable), for example an author field.
Inverted files
Mistral works with an inverted index structure which is implemented as indexed sequential files. The configuration provides some flexibility by allowing, for example, the grouping together several fields in the same index. The software package has a set of tools for managing or reorganizing these files.
See also
IBM STAIRS
SPIRES
BRS/Search
References
Information retrieval systems
History of computing in France | Mistral (software) | [
"Technology"
] | 464 | [
"Information technology",
"Information retrieval systems",
"History of computing",
"History of computing in France"
] |
73,755,426 | https://en.wikipedia.org/wiki/Null%20infinity | In theoretical physics, null infinity is a region at the boundary of asymptotically flat spacetimes. In general relativity, straight paths in spacetime, called geodesics, may be space-like, time-like, or light-like (also called null). The distinction between these paths stems from whether the spacetime interval of the path is positive (corresponding to space-like), negative (corresponding to time-like), or zero (corresponding to null). Light-like paths physically correspond to physical phenomena which propagate through space at the speed of light, such as electromagnetic radiation and gravitational radiation. The boundary of a flat spacetime is known as conformal infinity, and can be thought of as the end points of all geodesics as they go off to infinity. The region of null infinity corresponds to the terminus of all null geodesics in a flat Minkowski space. The different regions of conformal infinity are most often visualized on a Penrose diagram, where they make up the boundary of the diagram. There are two distinct regions of null infinity, called past and future null infinity, which can be denoted using a script '' as and . These two regions are often referred to as 'scri-plus' and 'scri-minus' respectively. Geometrically, each of these regions actually has the structure of a topologically cylindrical three dimensional region.
The study of null infinity originated from the need to describe the global properties of spacetime. While early methods in general relativity focused on the local structure built around local frames of reference, work beginning in the 1960s began analyzing global descriptions of general relativity, analyzing the structure of spacetime as a whole. The original study of null infinity originated with Roger Penrose's work analyzing black hole spacetimes. Null infinity is a useful mathematical tool for analyzing behavior in asymptotically flat spaces when limits of null paths need to be taken. For instance, black hole spacetimes are asymptotically flat, and null infinity can be used to characterize radiation in the limit that it travels outward away from the black hole. Null infinity can also be considered in the context of spacetimes which are not necessarily asymptotically flat, such as in the FLRW cosmology.
Conformal compactification in Minkowski spacetime
The metric for a flat Minkowski spacetime in spherical coordinates is . Conformal compactification induces a transformation which preserves angles, but changes the local structure of the metric and adds the boundary of the manifold, thus making it compact. For a given metric , a conformal compactification scales the entire metric by some conformal factor such that such that all of the points at infinity are scaled down to a finite value. Typically, the radial and time coordinates are transformed into null coordinates and . These are then transformed as and in order to use the properties of the inverse tangent function to map infinity to a finite value. The typical time and space coordinates may be introduced as and . After these coordinate transformations, a conformal factor is introduced, leading to a new unphysical metric for Minkowski space:
.
This is the metric on a Penrose diagram, illustrated. Unlike the original metric, this metric describes, a manifold with a boundary, given by the restrictions on and . There are two null surfaces on this boundary, corresponding to past and future null infinity. Specifically, future null infinity consists of all points where and , and past null infinity consists of all points where and .
From the coordinate restrictions, null infinity is a three dimensional null surface, with a cylindrical topology .
The construction given here is specific to the flat metric of Minkowski space. However, such a construction generalizes to other asymptotically flat spaces as well. In such scenarios, null infinity still exists as a three dimensional null surface at the boundary of the spacetime manifold, but the manifold's overall structure might be different. For instance, in Minkowski space, all null geodesics begin at past null infinity and end at future null infinity. However, in the Schwarzschild black hole spacetime, the black hole event horizon leads to two possibilities: geodesics may end at null infinity, but may also end at the black hole's future singularity. The presence of null infinity (along with the other regions of conformal infinity) guarantees geodesic completion on the spacetime manifold, where all geodesics terminate either at a true singularity or intersect the boundary of infinity.
Other physical applications
The symmetries of null infinity are characteristically different from that of the typical regions of spacetime. While the symmetries of a flat Minkowski spacetime are given by the Poincaré group, the symmetries of null infinity are instead given by the Bondi–Metzner–Sachs (BMS) group. The work by Bondi, Metzner, and Sachs characterized gravitational radiation using analyses related to null infinity, whereas previous work such as the ADM framework dealt with characterizations of spacelike infinity. In recent years, interest has grown in studying gravitons on the boundary null infinity. Using the BMS group, quanta on null infinity can be characterized as massless spin-2 particles, consistent with the quanta of general relativity being gravitons.
References
General relativity
Lorentzian manifolds
Theoretical physics
Wikipedia Student Program | Null infinity | [
"Physics"
] | 1,093 | [
"General relativity",
"Theoretical physics",
"Theory of relativity"
] |
73,756,187 | https://en.wikipedia.org/wiki/GP-7%20gas%20mask | The GP-7 gas mask is a civilian gas mask that was produced by the Soviet Union during the Cold War era. The mask was designed to provide protection to civilians against nuclear, biological, and chemical (NBC) agents during the threat of the Cold War. It is distinguished from its military counterpart, the PMK , which was intended to be used exclusively for military purposes as opposed to the GP-7 which was designed solely for civil defense.
Production
The GP-7 is made from a black rubbery material that was intended to be both durable and flexible. It has two circular eyepieces that provide a wide field of vision and allow the wearer to easily see in any direction. The mask also features a voice diaphragm for clear communication, a drinking tube for hydration while wearing the mask, and an exhale valve designed to prevent the buildup of moisture in the mask.
The GP-7 gas mask has a "helmet-mask" design, which allows it to fit over the head and be worn with a variety of military headgear. The mask has an adjustable elastic head harness and a rubber seal that ensures a secure and comfortable fit. The mask also has a lightweight design, which makes it easy to wear for extended periods of time.
The GP-7 gas mask uses a Gost 40mm filter thread that allows it to be equipped with a variety of different filters, and each filter was usually made for a collective or specific threat. The filter can be attached on the users left side of the mask. The filter provides protection against a wide range of NBC agents, including chemical warfare agents like Sarin and mustard gas, as well as biological agents like anthrax and smallpox, although mostly intended to be used for ammonia and its derivatives. For the safety of the wearer, it is to be noted that numerous other gas masks, such as the GP-5, have filters similar to these and have been proven to contain asbestos, arsenic and chromium.
The GP-7 gas mask was designed to be durable and long-lasting, and has been tested extensively in a variety of conditions. It was also designed to be easy to use and maintain, with spare parts and accessories readily available. The mask comes with a carrying bag for easy storage and transport, as well as an instruction manual that provides detailed information on how to use and maintain the mask.
Components
Front body
Filter
Inhale valve assembly
Visual assembly (sight glass and inner and outer clips)
Speaking diaphragm membrane (intercom)
Exhale valve assembly
Obturator for reliable sealing
Occipital plate (headpiece)
Front strap
Temporal region cranial straps
Buckles
Cheek straps.
Specifications
The mass of the gas mask included without the bag is no more than 900 grams.
The area of the field of view is not less than 60%.
Resistance to constant airflow during inhalation at a volumetric air flow of 30 dm³ / min - no more than 176.4 Pa. (18 mm water column)
The volume content of carbon dioxide in the inhaled air is not more than 1.0%
The coefficient of suction under the front part of the standard oil mist aerosol is no more than 0.001% .
The FPC permeability coefficient for standard oil mist aerosol is no more than 0.001%.
Permeability coefficient for radioactive iodine-131 vapours - no more than 0.01%
The operating temperature range is from minus 40 to 40 degrees Celsius Or minus 40 to 104 degrees Fahrenheit.
FPC protective action time for hazardous chemicals at an air flow rate of 30 dm³/min.
Hydrogen cyanide at a concentration of 5.0 mg / dm³ - at least 18 minutes.
Cyanogen chloride at a concentration of 5.0 mg / dm³ - at least 18 minutes.
Hydrogen sulfide at a concentration of 10.0 mg / dm³ - at least 25 minutes.
Chlorine at a concentration of 5.0 mg / dm³ - at least 40 minutes.
Hydrochloric acid at a concentration of 5.0 mg / dm³ - at least 20 minutes.
Tetraethyllead at a concentration of 2.0 mg / dm³ - at least 50 minutes.
Ethylmercaptan at a concentration of 5.0 mg / dm³ - at least 40 minutes.
Nitrobenzene at a concentration of 5.0 mg / dm³ - at least 40 minutes.
Phenol at a concentration of 0.2 mg / dm³ - at least 200 minutes.
Furfural at a concentration of 1.5 mg / dm³ - at least 300 minutes.
FPC protective action time when used with an additional DPG-3 cartridge for hazardous chemicals at an air flow rate of 30 dm³/min.
Hydrogen cyanide at a concentration of 5.0 mg / dm³ - at least 18 minutes.
Cyanogen chloride at a concentration of 5.0 mg / dm³ - at least 18 minutes.
Hydrogen sulfide at a concentration of 10.0 mg / dm³ - at least 50 minutes.
Chlorine at a concentration of 5.0 mg / dm³ - at least 100 minutes.
Hydrochloric acid at a concentration of 5.0 mg / dm³ - at least 30 minutes.
Tetraethyllead at a concentration of 2.0 mg / dm³ - at least 500 minutes.
Ethylmercaptan at a concentration of 5.0 mg / dm³ - at least 120 minutes.
Nitrobenzene at a concentration of 5.0 mg / dm³ - at least 70 minutes.
Phenol at a concentration of 0.2 mg / dm³ - at least 800 minutes.
Furfural at a concentration of 1.5 mg / dm³ - at least 400 minutes.
Ammonia at a concentration of 5.0 mg / dm³ - at least 60 minutes.
Dimethylamine at a concentration of 5.0 mg / dm³ - at least 80 minutes.
Modifications
From 2008 to 2014, a number of Russian manufacturing enterprises developed and produced a range of modifications of the GP-7 (GP-7V) civilian gas mask. The development was based on the use of similar face parts from the PMG (PMG-V) and their modifications - PMU (PMU-V), as well as filters in metal housings, such as GP-7KB-Universal (later renamed to FK-Universal), VK 320, VK 450 and others. Additionally, some manufacturing enterprises produced variations of civilian gas masks with plastic cases for filters, such as GP-7BV (GP-7B) and GP-7B (GP-7VMB). However, in these variations, in addition to the use of different materials for the filters, there were other significant design features that do not allow these variations of gas masks to be unambiguously classified as modifications of the GP-7 (GP-7V) gas mask. Currently, the following modifications of the GP-7 (GP-7V) are the most widely used: GP-7VM, GP-7VMT, GP-8V, GP-7B Universal (GP-7BV Universal), GP-9, UZS VK and MZS VK.
Despite the wide variety of modifications, the GP-7 (GP-7V) civilian gas mask still remains unparalleled in a number of indicators of protective action time for substances such as chlorine, hydrogen sulfide, and, when used with an additional DPG-3 cartridge, ammonia.
Packaging and storage
GP-7 were packed, transported and stored in their original packaging - wooden boxes, which were sealed by and at the manufacturing warehouse. Each box contains 20 sets of gas masks: 8 sets with face parts of size 1, 8 sets of face parts of size 2, 4 sets of face parts of size 3. Each box contains a manual for the operation of the gas mask. In box No. 1 of each batch of gas masks, a form for the batch is inserted. As a rule, each batch contains 1000 pieces of civilian gas masks GP-7 (50 boxes).
The warranty period of storage of the civilian gas mask GP-7 provided by the manufacturers is 12 years from the date of manufacture, with the exception of non-fogging films NPN-59, the warranty period of which is 7 years.
Additional information
The GP-7 provides a limited time of protective action against ammonia and its derivatives. It does not provide protection against organic gases and vapours with a boiling point of less than 65 °C [149 °F] such as: methane, ethane, acetylene, ethylene oxide, isobutane, carbon monoxide and nitrogen oxides.
To provide additional protection against ammonia and its derivatives, the mask can be equipped with an additional DPG-3 cartridge, which, when used in conjunction with the FPK GP-7K, is connected to the front part of the connecting corrugated tube. To protect against carbon monoxide and nitrogen oxides, it is necessary to use a set of filters of special PZU-PC.
Quality control and acceptance of civilian gas masks GP-7 at manufacturing enterprises is carried out by military representations of the Ministry of Defence of the Russian Federation.
Pop culture and use today
The GP-7 gas mask was widely used by Soviet and Warsaw Pact civilians during the Cold War era, and is often used today by various military forces and military enthusiasts today. While it has become slightly outdated compared to newer models of gas masks, it remains a popular choice for cosplayers, collectors and enthusiasts of Gas Mask equipment. It is also still occasionally used in modern Post-Soviet countries for civil defence.
References
Gas masks of the Soviet Union | GP-7 gas mask | [
"Chemistry"
] | 2,042 | [
"Gas masks",
"Gas masks of the Soviet Union"
] |
73,756,287 | https://en.wikipedia.org/wiki/GJ%201252 | GJ 1252 is a red dwarf star located away from the Solar System in the constellation of Telescopium. The star has about 38% the mass and 39% the radius of the Sun, and a temperature of about . GJ 1252 is orbited by one known exoplanet.
Planetary system
GJ 1252 was found to have a planet, GJ 1252 b, in 2019 using transit observations from TESS. It is a terrestrial planet larger than Earth, with about 1.3 times the mass and 1.18 times the radius of Earth. Orbiting its star with a very short period of just 12.4 hours, it is presumably tidally locked. Secondary eclipse observations have shown that GJ 1252 b lacks a significant atmosphere, similar to LHS 3844 b and TRAPPIST-1b, and have measured its dayside temperature at about .
References
Telescopium
M-type main-sequence stars
Planetary systems with one confirmed planet
1252
1078
370133522 | GJ 1252 | [
"Astronomy"
] | 208 | [
"Telescopium",
"Constellations"
] |
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