id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
|---|---|---|---|---|---|---|
63,192,698 | https://en.wikipedia.org/wiki/National%20Timing%20Centre | The United Kingdom National Timing Centre is the proposed network of atomic clocks consisting of a central building, and a series of other locations across the UK.
The cost of the new system will cost £36 million, but additionally the UK government has given £6.7 million through Innovate UK Funding and £40 million toward a new research program Quantum Technologies for fundamental physics to support UK research and investment.
Locations: University of Birmingham; University of Strathclyde; University of Surrey; BT Adastral Park, Suffolk; BBC, Manchester; National Physical Laboratory, Teddington.
History
Discussions around a United Kingdom National Timing Centre began on 19 February 2020 as a response to the United Kingdom's over reliance on the European Union Global Navigation Satellite System (GNSS), and the United States of America's (USA) GNSS Systems.
References
External links
National Timing Centre at the National Physical Laboratory
Standards organisations in the United Kingdom | National Timing Centre | [
"Physics"
] | 190 | [
"Spacetime",
"Physical quantities",
"Time",
"Time stubs"
] |
63,193,936 | https://en.wikipedia.org/wiki/Cl%C3%A0udia%20Valls | Clàudia Valls Anglés is a mathematician and an expert in dynamical systems. She is an associate professor in the Instituto Superior Técnico of the University of Lisbon in Portugal.
Education
Valls completed a doctorate at the University of Barcelona in 1999. Her dissertation, The Classical Arnold Example of Diffusion with Two Equal Parameters, was supervised by .
Books
Valls is the co-author of books with Luís Barreira and others, including:
Instability in Hamiltonian systems (with Antonio Pumariño, Electronic Journal of Qualitative Theory of Differential Equations Monograph Series, Vol. 1, 2005)
Stability of nonautonomous differential equations (with Luís Barreira, Lecture Notes in Mathematics, Vol. 1926, Springer, 2008)
Complex analysis and differential equations (with Luís Barreira, Springer Undergraduate Mathematics Series, Springer, 2012), translated into French as Analyse complexe et équations différentielles (Enseignement SUP-Maths, EDP Sciences, 2011)
Exercices d’analyse complexe et équations différentielles [Exercises in complex analysis and differential equations] (with Luís Barreira, Enseignement SUP-Maths, EDP Sciences, 2011)
Equações diferenciais: Teoria qualitativa (with Luís Barreira, Ensino da Ciência e da Tecnologia, Vol. 33, IST Press, 2010), translated into English as Ordinary differential equations: Qualitative theory (Graduate Studies in Mathematics, Vol. 137, American Mathematical Society, 2012)
Dynamical systems: An introduction (with Luís Barreira and Davor Dragičević, Universitext, Springer, 2013; originally published in Portuguese in 2012)
Exercises in linear algebra (with Luís Barreira, World Scientific, 2016)
Admissibility and hyperbolicity (with Luís Barreira, SpringerBriefs in Mathematics, Springer, 2018)
Dynamical systems by example (with Luís Barreira, Problem Books in Mathematics, Springer, 2019)
References
Year of birth missing (living people)
Living people
21st-century Spanish mathematicians
21st-century Portuguese mathematicians
Women mathematicians
Dynamical systems theorists
University of Barcelona alumni
Academic staff of the University of Lisbon | Clàudia Valls | [
"Mathematics"
] | 447 | [
"Dynamical systems theorists",
"Dynamical systems"
] |
63,194,019 | https://en.wikipedia.org/wiki/Grainyhead-like%20gene%20family | Grainyhead-like genes are a family of highly conserved transcription factors that are functionally and structurally homologous across a large number of vertebrate and invertebrate species. For an estimated 100 million years or more, this genetic family has been evolving alongside life to fine tune the regulation of epithelial barrier integrity during development, fine-tuning epithelial barrier establishment, maintenance and subsequent homeostasis. The three main orthologues, Grainyhead-like 1, 2 and 3, regulate numerous genetic pathways within different organisms and perform analogous roles between them, ranging from neural tube closure, wound healing, establishment of the craniofacial skeleton and repair of the epithelium. When Grainyhead-like genes are impaired, due to genetic mutations in embryogenesis, it will cause the organism to present with developmental defects that largely affect ectodermal (and sometimes also endodermal) tissues in which they are expressed. These subsequent congenital disorders, including cleft lip and exencephaly, vary greatly in their severity and impact on the quality of life for the affected individual. There is much still to learn about the function of these genes and the more complex roles of Grainyhead-like genes are yet to be discovered.
Gene Family
The Grainyhead-like (Grhl) gene family is a group of highly conserved transcription factors, which work to regulate the expression of specific target genes. Grainyhead (Grh) was originally identified in Drosophila as being implicated within development through its role of regulating numerous genetic pathways. While Drosophila has only one Grh gene, there are three homologues currently known across other species (Grhl1-3). It appears that all members of the Grhl gene family are involved in epidermal barrier integrity, including its formation and repair, and are tightly regulated to prevent physical defects. The Grhl family of genes are found in a range of organisms, from humans to fish and fungi, and all have similar roles to each other in regards to the developmental processes that they have a role in regulating. This could indicate that the Grhl genes could be one of the earliest genes to arise within our genome, providing vital functions for survival of an early common ancestor.
Conservation
The Grhl gene family is tightly conserved between species across an estimated millions of years of evolution, also maintaining the binding site (AACCGGTT) on the target genes of Grhl. While the presence of the Grhl genes varies between species, the functions regulated remain largely analogous. The reason for the presence of multiple Grhl orthologues would likely be due to speciation and the evolution of species from a common ancestor over time. Due to many animals possessing Grhl genes, there are many possible animal models available for research on the Grhl family. At present, the most characterized are the models of Drosophila, mouse and zebrafish. Interestingly, Grh was also identified in fungi, which lack epidermal tissue and instead utilize a cell wall. This gives evidence that the formation of physical barriers across all, or a large variety of, species may have had an evolutionary ancestor that initially developed barrier formation as a result of the presence of a Grhl gene.
Orthologues
Grhl1
Grhl1 is, much like the rest of the family of genes, involved in epithelial barrier formation and wound healing while the loss of Grhl1 is often associated with the activation of the skin's immune system. Knockout of grhl1 in zebrafish has shown to cause hair cell apoptosis within the inner ear which leads to sensory epithelium damage that consequently causes deafness. Grhl1 may carry out its functions through regulation of downstream genetic targets such as desmosomal cadherin genes (Dsg1) and other cadherin family genes, as a reduction in Grhl1 yields similar phenotypes to that of reduced Dsg1 expression. The desmosomes are the intercellular junctions within the epidermis and genes like Dsg1 regulate cadherin expression within these junctions. The development and differentiation of epidermal cells is regulated by Grhl1 in a tissue-specific manner in vertebrates, meaning that different tissues will respond differently to Grhl1 regulation. In regards to other craniofacial features, such as the palate and jaw, Grhl1 does not currently have any known significant role in their development.
Grhl2
Grhl2 is involved in lower jaw formation of mammals, among other craniofacial developmental processes. It is also evolutionarily closest to Grhl1, compared to Grhl3, while still exhibiting the highly conserved functions that all Grhl genes share. It also appears that Grhl2 is involved in the fusion of the facial bones and that disruption to the regulation of Grhl2 can lead to cranioschisis/split face during embryonic development, often causing death. Continuing with the trend of incomplete fusion, the formation of the neural tube and abdominal wall is also regulated by Grhl2, evident by observation of incomplete closure of these structures, leading to spina bifida and thoracoabdominoschisis, following loss of Grhl2 function in mutant mice models for Grhl2. Additionally, over-expression of Grhl2 can also lead to mice developing spina bifida, showing the delicate balance in regulation required for Grhl2. Grhl2 is also related to breast cancer progression due to its ability to regulate epithelial cells and other processes such as epithelial-mesenchymal transition (EMT), although it is not known if EMT is promoted or inhibited by Grhl2. However, tumour progression is more associated with the epithelial tissue phenotype. Interestingly, within zebrafish there are two separate orthologues, grhl2a and grhl2b. Comparing the homology of these two orthologues to the human and mice equivalent, Grhl2, showed that grhl2b had 36 out of 47 amino acids identical (77% identical), meaning it was slightly more conserved than grhl2a, which had 34 out of 47 (72% identical). grhl2b loss causes apoptosis throughout the brain and the nervous system of zebrafish. A similar result came from a mouse study and led to the belief that grhl2b is a key survival factor for neural cells.
Grhl3
Much the same as the previous two orthologues, Grhl3 is involved in the regulation of epidermal tissue, such as the formation of the jaw, neural tube and other craniofacial features, and does so across both land and aquatic organisms. Grhl3 is a downstream target of Irf6, and plays a key role in processes involving fusion during development much like Grhl2, especially so in the oral palate and spinal cord. A mutation of Grhl3, that causes an increase or a decrease in expression, can lead to Van der Woude syndrome, which is characterized by phenotypes that include cleft lip and/or palate and spina bifida. Primarily, Grhl3 appears to play a vital role for regulating the development of the craniofacial skeleton. A genome-wide association study found that Grhl3 is an etiological variant for a nonsyndromic form of cleft palate, ~50% of all cleft palate cases, highlighting the level of impact that dysregulation of Grhl3 has on development. Apart from the defects that are physically noticeable, Grhl3 is also expressed in the brain of mice embryos and has been shown to regulate the impulsiveness and anxiety levels of mice. Furthermore, it appears that grhl3 regulates the enveloping layer of zebrafish and axial extension as well as cell size and identity during embryonic development. If expression is disrupted during the early stages of disruption it will lead to severe defects that can lead to the death of the embryo before epiboly is complete. Epiboly is the stage of development for select organisms, such as the xenopus, sea urchin and zebrafish, when the cells of the embryo grow and migrate to the opposite end of the yolk sac to envelop it to continue developing.
Developmental defects
Associated defects/diseases
There are thousands of deaths a year of infants, either during or shortly after birth, and the leading cause of these deaths are congenital birth defects (CBDs), which are defined as abnormalities of the chromosomes. In the year 2004, CBDs had been the cause of over 139,000 hospitalizations in the U.S. and had cost the community $2.6 billion in healthcare and medical supplies. While some CBDs can be easily fixed by simple surgery or medication, such as cleft lip, there are still life threatening diseases that are caused by mutations to the Grhl family members or genetic pathways that they are associated with. In developing countries, where there is a large percentage of the population in poverty, families struggle to receive the necessary treatment to combat CBDs and the extent at which the quality of life is affected is continually worsening. Members of the Grhl3 family are closely related to endodermal tissues and the issues that can arise from a mutation in one of the Grhl family members can include respiratory problems, loss of hearing, spina bifida and much more. Grhl3 has been shown to be a downstream target of genes such as Fgf8 and Irf6, of which the associated pathways are involved in the aetiology of Van der Woude syndrome.
Role in disease
References
Protein families | Grainyhead-like gene family | [
"Biology"
] | 1,994 | [
"Protein families",
"Protein classification"
] |
63,195,300 | https://en.wikipedia.org/wiki/Computing%20the%20Continuous%20Discretely | Computing the Continuous Discretely: Integer-Point Enumeration in Polyhedra is an undergraduate-level textbook in geometry, on the interplay between the volume of convex polytopes and the number of lattice points they contain. It was written by Matthias Beck and Sinai Robins, and published in 2007 by Springer-Verlag in their Undergraduate Texts in Mathematics series (Vol. 154). A second edition was published in 2015, and a German translation of the first edition by Kord Eickmeyer, Das Kontinuum diskret berechnen, was published by Springer in 2008.
Topics
The book begins with a motivating problem, the coin problem of determining which amounts of money can be represented (and what is the largest non-representable amount of money) for a given system of coin values.
Other topics touched on include face lattices of polytopes and the Dehn–Sommerville equations relating numbers of faces; Pick's theorem and the Ehrhart polynomials, both of which relate lattice counting to volume; generating functions, Fourier transforms, and Dedekind sums, different ways of encoding sequences of numbers into mathematical objects; Green's theorem and its discretization; Bernoulli polynomials; the Euler–Maclaurin formula for the difference between a sum and the corresponding integral; special polytopes including zonotopes, the Birkhoff polytope, and permutohedra; and the enumeration of magic squares. In this way, the topics of the book connect together geometry, number theory, and combinatorics.
Audience and reception
This book is written at an undergraduate level, and provides many exercises, making it suitable as an undergraduate textbook. Little mathematical background is assumed, except for some complex analysis towards the end of the book. The book also includes open problems, of more interest to researchers in these topics. As reviewer Darren Glass writes, "Even people who are familiar with the material would almost certainly learn something from the clear and engaging exposition that these two authors use."
Reviewer Margaret Bayer calls the book "coherent and tightly developed ... accessible and engaging", and reviewer Oleg Karpenkov calls it "outstanding".
See also
List of books about polyhedra
References
Polytopes
Lattice points
Volume
Mathematics textbooks
2007 non-fiction books
2015 non-fiction books
Springer Science+Business Media books | Computing the Continuous Discretely | [
"Physics",
"Mathematics"
] | 483 | [
"Scalar physical quantities",
"Physical quantities",
"Lattice points",
"Quantity",
"Size",
"Extensive quantities",
"Volume",
"Wikipedia categories named after physical quantities",
"Number theory"
] |
63,196,482 | https://en.wikipedia.org/wiki/Physiology%20of%20underwater%20diving | The physiology of underwater diving is the physiological adaptations to diving of air-breathing vertebrates that have returned to the ocean from terrestrial lineages. They are a diverse group that include sea snakes, sea turtles, the marine iguana, saltwater crocodiles, penguins, pinnipeds, cetaceans, sea otters, manatees and dugongs. All known diving vertebrates dive to feed, and the extent of the diving in terms of depth and duration are influenced by feeding strategies, but also, in some cases, with predator avoidance. Diving behaviour is inextricably linked with the physiological adaptations for diving and often the behaviour leads to an investigation of the physiology that makes the behaviour possible, so they are considered together where possible. Most diving vertebrates make relatively short shallow dives. Sea snakes, crocodiles, and marine iguanas only dive in inshore waters and seldom dive deeper than . Some of these groups can make much deeper and longer dives. Emperor penguins regularly dive to depths of for 4 to 5 minutes, often dive for 8 to 12 minutes, and have a maximum endurance of about 22 minutes. Elephant seals stay at sea for between 2 and 8 months and dive continuously, spending 90% of their time underwater and averaging 20 minutes per dive with less than 3 minutes at the surface between dives. Their maximum dive duration is about 2 hours and they routinely feed at depths between , though they can exceed depths of . Beaked whales have been found to routinely dive to forage at depths between , and remain submerged for about 50 minutes. Their maximum recorded depth is , and the maximum duration is 85 minutes.
Air-breathing marine vertebrates that dive to feed must deal with the effects of pressure at depth, hypoxia during apnea, and the need to find and capture their food. Adaptations to diving can be associated with these three requirements. Adaptations to pressure must deal with the mechanical effects of pressure on gas-filled cavities, solubility changes of gases under pressure, and possible direct effects of pressure on the metabolism, while adaptations to breath-hold capacity include modifications to metabolism, perfusion, carbon dioxide tolerance, and oxygen storage capacity. Adaptations to find and capture food vary depending on the food, but deep-diving generally involves operating in a dark environment.
Diving vertebrates have increased the amount of oxygen stored in their internal tissues. This oxygen store has three components; oxygen contained in the air in the lungs, oxygen stored by haemoglobin in the blood, and by myoglobin, in muscle tissue, The muscle and blood of diving vertebrates have greater concentrations of haemoglobin and myoglobin than terrestrial animals. Myoglobin concentration in locomotor muscles of diving vertebrates is up to 30 times more than in terrestrial relatives. Haemoglobin is increased by both a relatively larger amount of blood and a larger proportion of red blood cells in the blood compared with terrestrial animals. The highest values are found in the mammals which dive deepest and longest.
Body size is a factor in diving ability. A larger body mass correlates to a relatively lower metabolic rate, while oxygen storage is directly proportional to body mass, so larger animals should be able to dive for longer, all other things being equal. Swimming efficiency also affects diving ability, as low drag and high propulsive efficiency requires less energy for the same dive. Burst and glide locomotion is also often used to minimise energy consumption, and may involve using positive or negative buoyancy to power part of the ascent or descent.
The responses seen in seals diving freely at sea are physiologically the same as those seen during forced dives in the laboratory. They are not specific to immersion in water, but are protective mechanisms against asphyxia which are common to all mammals but more effective and developed in seals. The extent to which these responses are expressed depends greatly on the seal's anticipation of dive duration.
The regulation of bradycardia and vasoconstriction of the dive response in both mammals and diving ducks can be triggered by facial immersion, wetting of the nostrils and glottis, or stimulation of trigeminal and glossopharyngeal nerves.
Animals cannot convert fats to glucose, and in many diving animals, carbohydrates are not readily available from the diet, nor stored in large quantities, so as they are essential for anaerobic metabolism, they could be a limiting factor.
Decompression sickness (DCS) is a disease associated with metabolically inert gas uptake at pressure, and its subsequent release into the tissues in the form of bubbles. Marine mammals were thought to be relatively immune to DCS due to anatomical, physiological and behavioural adaptations that reduce tissue loading with dissolved nitrogen during dives, but observations show that gas bubbles may form, and tissue injury may occur under certain circumstances. Decompression modelelling using measured dive profiles predict the possibility of high blood and tissue nitrogen tensions.
Range of performance
Strong allometric relationships have been observed between body mass and maximum diving depths and durations in marine mammals, birds and marine turtles. Exceptions can be seen in baleen whales, eared seals and flighted diving birds, which showed no correlation between size and maximum diving depth. Penguins showed the highest correlations of diving capacity with body mass, followed by toothed whales and true seals. Baleen whales show a correlation between mass and maximum dive duration. Comparisons between the groups show that alcids, penguins, and true seals are exceptional divers relative to their masses and that baleen whales dive to shallower depths and for shorter durations than would be expected from their size. Many of these variations can be explained by adaptation to ecological feeding niches exploited by the animals.
Marine mammals
Marine mammals adaptation to deep and long duration breath-hold diving involves more efficient use of lungs that are proportionately smaller than those of terrestrial animals of similar size. The adaptations to the lungs allow more efficient extraction of oxygen from inhaled air, and a higher exchange rate of air of up to 90% of each breath. Their blood chemistry extracts more oxygen and faster due to high red blood cell count, and high concentrations of myoglobin in the muscles stores more oxygen for availability during a dive. They also have a relatively high tolerance to carbon dioxide which builds up during breath-hold, and lactic acid, produced by anaerobic muscle work. The lungs and ribs are collapsible, allowing them to collapse without damage under the pressure of great depths They do not have air-filled sinuses in the facial bones.
There are differences in the diving strategies of marine mammals, which vary both with depth range and taxonomic grouping. Some of these remain inadequately explained. Some, such as Cuvier's beaked whale, routinely exceed their aerobic dive limit, making a relatively long recovery period necessary, while others, like elephant seals, appear to require very little recovery time between dives to similar depth, indicating that they tend to remain within their aerobic limits on almost all dives.
Many aquatic mammals such as seals and whales dive after full or partial exhalation, which would reduce the amount of nitrogen available to saturate the tissues by 80 to 90%.
Aquatic mammals are also less sensitive to low alveolar oxygen concentrations and high carbon dioxide concentrations than purely terrestrial mammals.
Seals, whales and porpoises have slower respiratory rates and larger tidal volume to total lung capacity ratio than land animals which gives them a large exchange of gas during each breath and compensates for low respiratory rate. This allows greater utilisation of available oxygen and reduced energy expenditure.
In seals, bradycardia of the diving reflex reduces heart rate to about 10% of the resting level at the start of a dive.
Deep diving mammals do not rely on increased lung volume to increase oxygen stores. The whales with long and deep diving capabilities have relatively small lung volumes which collapse during the dive, and seals dive following partial exhalation with a similar effect. Short duration diving mammals have lung volumes similar to their terrestrial equivalents and dive with full lungs, using the contents as an oxygen store. The oxygen affinity of the blood is related to lung volume. Where the lungs do not represent an oxygen store, the oxygen affinity is low to maximise the unloading of oxygen and to maintain a high tissue oxygen tension. Where the lungs are utilised as an oxygen store, the affinity is high and maximises uptake of oxygen from the alveolar volume.
Adaptation of oxygen storage capacity of blood and muscle in diving mammals is an important factor in their diving endurance, and ranges from roughly equivalent to terrestrial mammals to nearly ten times as much, in proportion to the duration of dives and the metabolic demand during dives.
Swimming adaptations of drag reduction by hydrodynamically streamlined body forms and efficient swimming actions and appendages reduce the amount of energy expended in the diving, hunting and surfacing activity.
Heat loss is controlled by reducing the surface to volume ratio, and thick insulating layers of blubber and/or fur, which also help with streamlining for reduced drag. Exposed areas with relatively high circulation may use a rete mirabile counterflow heat exchange system of blood vessels to reduce heat loss.
Marine mammals use sound to communicate underwater, and many species use echolocation to navigate and locate prey. Pinnipeds and fissipeds have facial whiskers capable of locating prey by detecting vibrations in the water.
The hearts of marine mammals are typical of mammals. The heart is a slightly lower percentage of body mass in the great whales compared to pinnipeds and smaller cetaceans.
Chamber size, stroke volume, resting cardiac output and heart rate are also in the general mammalian range, but the hearts of diving mammals are dorso-ventrally flattened, with enlarged right ventricular chambers, and, in some species, the thickness of the right ventricular wall may be increased. The dorso-ventral flattening prevents chest compression from compromising filling, and thicker walls may compensate for the effects of increased vascular resistance and lung collapse during chest compression.
Dense innervation of arteries in seals by sympathetic nerves may be part of a system for maintaining vasoconstriction of the dive response independent of local metabolite induced vasodilation. Venous capacitance is highly developed, especially in phocid seals and whales, and includes a large hepatic sinus and posterior vena cava, and is thought to be related to the large blood volume of the animals. The relatively large spleen also injects extremely high hematocrit blood into the hepatic sinus during dives and is a significant storage organ for red blood cells.
Parallel counter-flowing arteries and veins characteristic of countercurrent exchange units are present in the dorsal fins, flukes, and flippers of cetaceans, and are considered to conserve body heat by transferring it to the returning venous flow before arterial blood is exposed to the high heat-loss areas. There is also a superficial venous system by which excess heat can be dissipated to the surroundings.
The ascending aorta of pinnipeds is dilated to form an elastic aortic bulb which can hold the stroke volume of the heart and is thought to function as a hydraulic accumulator, to maintain blood pressure and flow during the long diastole of bradycardia, which is critical to the perfusion of the brain and heart, and compensates for the high resistance of the circulatory system due to vasoconstriction.
Retia mirabilia are networks of anastomosing arteries and veins and are found in cetaceans and sirenians. Their function is not altogether clear and may involve windkessel functions, intrathoracic vascular engorgement to prevent lung squeeze, thermoregulation, and the trapping of gas bubbles in the blood.
In most pinnipeds, there is a striated muscle sphincter at the level of the diaphragm around the posterior vena cava, innervated by the right phrenic nerve, and located cranial to the large hepatic sinus and inferior vena cava, which is most developed in phocid seals. The function of this sphincter is considered to be the regulation of venous return during bradycardia. Some whales also have a sphincter of the vena cava, and some cetaceans have smooth muscle sphincters around the intrahepatic parts of the portal vein. The precise function of these structures is not well understood.
Pinnipeds
Pinnipeds are carnivorous, fin-footed, semiaquatic marine mammals comprising the Odobenidae (walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals). There are 33 extant species of pinnipeds.
Two adaptations help seals to extend their time underwater. Oxygen storage capacity is greater than that of terrestrial mammals. They have more blood volume per body mass and greater numbers of red cells per blood volume. Muscle myoglobin is up to twenty times more concentrated than in terrestrial mammals.
Before diving, pinnipeds typically exhale to empty their lungs of half the air and then close their nostrils and throat cartilages to protect the trachea. Their unique lungs have airways that are highly reinforced with cartilaginous rings and smooth muscle, and alveoli that completely deflate during deeper dives. While terrestrial mammals are generally unable to empty their lungs, pinnipeds can reinflate their lungs even after complete respiratory collapse. The middle ear contains sinuses that probably fill with blood during dives, preventing middle ear squeeze. The heart of a seal is moderately flattened to allow the lungs to deflate. The trachea is flexible enough to collapse under pressure. During deep dives, any remaining air in their bodies is stored in the bronchioles and trachea, which prevents them from experiencing decompression sickness, oxygen toxicity and nitrogen narcosis. In addition, seals can tolerate large amounts of lactic acid, which reduces skeletal muscle fatigue during intense physical activity.
The main adaptations of the pinniped circulatory system for diving are the enlargement and increased complexity of veins to increase their capacity. Retia mirabilia forms blocks of tissue on the inner wall of the thoracic cavity and the body periphery. These tissue masses, which contain extensive contorted spirals of arteries and thin-walled veins, act as blood reservoirs that increase oxygen stores for use during diving. As with other diving mammals, pinnipeds have high amounts of hemoglobin and myoglobin stored in their blood and muscles. This allows them to stay submerged for long periods of time while still having enough oxygen. Deep-diving species such as elephant seals have blood volumes that makeup to 20% of their body weight. When diving, they reduce their heart rate and maintain blood flow only to the heart, brain and lungs. To keep their blood pressure stable, phocids have an elastic aorta that dissipates some energy of each heartbeat.
Pinnipeds have vascular sinuses in the middle ear which can fill with blood and reduce the volume of the air space and susceptibility to barotrauma, and have lungs and rib-cages which can almost completely collapse without injury, and in a sequence that removes the air from the alveoli relatively early in the dive.
Phocid seals
Southern elephant seals (Mirounga leonina) can dive as deep as 2000 m and stay underwater for as long as 120 min, which means that they are subjected to hydrostatic pressures of more than 200 atmospheres, but hydrostatic pressure is not a major problem, as at depths below about 100 m, depending on the species, the lungs and other air spaces have collapsed and for practical purposes, the animal will be incompressible, so that further increases in-depth pressure no longer have much effect. The tympanic membranes of the deep-diving hooded seal are protected by the cavernous tissue in the middle ear, which expands to fill the air space.
At great depths, the animal must also avoid the narcotic effects of extreme tissue nitrogen tension, oxygen poisoning and similar effects. The collapse of the lungs under pressure has an advantage, as because the airways are reinforced with more cartilage than usual, which extends to the openings of the alveolar sacs, the alveoli will collapse first under pressure which pushes the alveolar air into the airways where there is no gas exchange, and this reduces the nitrogen loading of the tissues to only part of a single breath per dive. The nitrogen loads may still build up to some extent over several consecutive dives, but this is greatly reduced in comparison with a human diver continuously breathing under pressure.
Except for technologically aided humans, air-breathing animals have to stop breathing during a dive, so the arterial oxygen content continuously decreases and the arterial carbon dioxide content continuously increases while no fresh air is available. The urge to breathe is primarily based on carbon dioxide concentration, and ventilatory response to increased carbon dioxide is known to be lower in seals than terrestrial mammals. This suppresses the urge to breathe, which is one aspect of increasing breath-hold duration. The other and more critical aspect is to have as much oxygen available as possible at the start of the dive, to use it economically throughout the dive, and to have sufficient oxygen available to sustain consciousness until the end of the dive when it can be replenished.
Phocid seals do not have particularly large lung volumes, and they normally exhale at the start of a dive to reduce buoyancy and avoid nitrogen uptake under pressure. The lungs progressively collapse during the dive, starting with the alveoli, where gas exchange takes place, and re-expand during the ascent, so some gas exchange may be possible even before surfacing. Blood shunted through the lungs during the deeper part of the dive undergoes little gas exchange. The surfactants in the lungs not only reduce surface tension but also reduce adhesion of the collapsed inner surfaces allowing easier re-expansion during the final phase of ascent.
The blood volume of seals is proportionately larger than terrestrial mammals, and the haemoglobin content is very high. This makes the oxygen-carrying capacity and the blood oxygen store very high, but it is not necessarily available at all times. Aortic haemoglobin concentration has been observed to rise in diving Weddell seals. High hematocrit blood is stored in the large spleen of deep-diving seals, and may be released into the circulation during a dive, making the spleen an important oxygen reservoir for use during a dive while reducing blood viscosity when the animal is breathing.
Seal muscle has a very high myoglobin concentration, which varies in different muscles and hooded seals have the capacity to store about six times as much oxygen as humans. Myoglobin has a considerably higher affinity for oxygen than haemoglobin, so if the muscles are perfused during a dive, the oxygen on the myoglobin will only become available when the oxygen level of the blood has been heavily depleted.
Although the hooded seal's mass-specific oxygen stores are about four times those of humans, it can dive 20 times longer. The oxygen stored is insufficient for aerobic consumption by all tissues, and differential distribution of blood oxygen store to the brain can allow less sensitive tissues to function anaerobically during a dive. Peripheral vasoconstriction largely excludes the skeletal muscles from perfusion during a dive, and use the oxygen stored locally in myoglobin, followed by anaerobic metabolism during a dive. When breathing again, the muscles are perfused and re-oxygenated, and there is a surge in arterial lactate for a short period until reoxygenation stabilises.
The problem of how the arteries remain constricted in the presence of increasing tissue pH due to intracellular lactate was found to be avoided by the ability to constrict arteries leading to the organs, rather than arteriole constriction within the organs as occurs in terrestrial animals. The vasoconstriction causes a large increase in resistance to flow and is compensated by a proportional reduction of heart rate to maintain a suitable blood pressure sufficient to provide the reduced circulation. A bulbous enlargement of the ascending aorta in seals has elastic walls and contributes to maintaining sufficient diastolic pressure during bradycardia.
The heart rate in seals may drop as low as 4 to 6 beats per minute to balance central arterial blood pressure with the large increase in peripheral vascular resistance. The bradycardia also contributes to a major reduction of cardiac workload, so that the reduced myocardial blood flow in diving seals is tolerable, and allows the heart to function in anaerobic metabolism without evidence of myocardial dysfunction.
Cerebral integrity in Weddell seals is maintained down to an arterial oxygen tension of 10 mmHg, which is much lower than the critical arterial oxygen tension of 25 to 40 mmHg at which impairment due to adenosine triphosphate production limitations are detected in brains of terrestrial mammals. Cerebral blood supply is well maintained to the end of a long dive, and glucose supply is fairly well maintained. Endogenous glycogen supplies are greater than in terrestrial mammals, but not large. In the deep-diving hooded seal neuroglobin levels are much the same as in terrestrial animals but are distributed differently, having greater concentrations in glial cells than in neurons, suggesting that glial cells may be more dependent on aerobic metabolism than neurons.
The brain is a major consumer of oxygen during dives, so reducing brain oxygen consumption would be an advantage. Controlled cooling of the brain has been observed in diving seals which are expected to reduce brain oxygen demand significantly, and also protect against possible hypoxic injury. The shivering response to brain cooling found in most mammals is inhibited as part of the diving response.
Renal blood supply during dives is also affected by selective arterial vasoconstriction and can drop below 10% of surface value, or be closed down altogether during prolonged dives, so the kidneys must be tolerant of warm ischemia for periods of up to an hour. Diving is associated with a large reduction to complete interruption of glomerular filtration and urine production in harbour seals.
During a dive, the blood supply to skeletal muscles in seals is almost completely shut off, and a massive buildup of lactic acid may occur, starting when the oxygen stored by the muscle myoglobin is used up, showing that the skeletal muscles rely on anaerobic metabolism for the latter part of long dives. This blood supply is restored on surfacing when the animal resumes breathing. Harbour seals, which dive for short durations, have a high capacity for aerobic metabolism in the swimming muscles, while Weddell seals, which are capable of very long duration dives, do not have aerobic capacities beyond those of terrestrial mammals. The high buildup of lactate in the skeletal muscles of seals during dives is compensated by a high buffering capacity, with a strong correlation between buffering capacity and myoglobin concentration, and between buffering capacity and muscle lactate dehydrogenase (LDH) activity. On resuming breathing, the muscles are reperfused gradually, which avoids excessive peaking of arterial pH.
The overall distribution of blood flow in seals during dives has been measured using radioactive microspheres. The studies show that most major organs, including kidneys, liver, gut, skeletal muscle, and heart, have severely reduced circulation, while the brain gets most of the residual blood supply. The details of the results vary between species and depend on the length of the dive and the diving capacity of the animals.
There are large vena cava and hepatic sinuses in which blood can be temporarily stored during a dive, controlled by a sphincter of striated muscle anterior to the diaphragm, which is controlled by a branch of the phrenic nerve. This sphincter prevents engorgement of the heart by constriction of the arteries through which the blood is shifted to the central veins, creating an oxygen-rich reserve of blood in the vena cava, which is released into the circulation in proportion to cardiac output. Towards the end of a dive, this reserve of venous blood may have a higher oxygen content than the arterial blood.
Apnea in seals is induced by stimulation of trigeminal and glossopharyngeal nerve receptors in the mouth. The consequent asphyxia stimulates peripheral chemoreceptors which induce increasing peripheral vasoconstriction and bradycardia. Conversely, if the peripheral chemoreceptors are stimulated by hypoxia while the animal is breathing, the ventilation, heart rate and vasodilation of skeletal muscles is increased.
Oxygen consumption during a dive can be reduced by about 70%, attributed to anaerobic metabolism and probably also cooling of the body.
Observations on seals diving unrestricted in open water indicate that bradycardia is not as common as laboratory work suggested. It appears that the animals respond differently to voluntary immersion compared to forced immersion, and when forced underwater and unable to predict the length of a dive, the seal would go into an emergency response against asphyxia with a strong bradycardia response. When the dive was at the option of the seal, the response was proportional to the time the seal intended to dive, and would generally remain in aerobic metabolism, which would require a far shorter recovery time and allow repeat dives after a short surface interval. Anticipatory tachycardia shortly before surfacing was also reported on voluntary dives.
When allowed to dive as they chose, Weddell seals would usually do a series of relatively short dives, with an occasional longer dive, and did not build up post-dive lactic acid in their arterial blood. This allowed very short recovery periods between dives, and a much longer total immersed time of up to 80% of the time underwater compared with anaerobic dives where the proportion of time underwater was greatly reduced. The length of time the seal can dive without arterial lactate buildup is termed the aerobic dive limit. It can be measured, but not reliably calculated. The large difference in oxygen affinity between haemoglobin and myoglobin does not allow the transfer of oxygen from muscle stores to blood for uses in other tissues, so for a dive to be fully aerobic, the blood flow to working muscles must be restricted so the oxygen on the myoglobin can be used locally, keeping the haemoglobin supplies for the vital organs, particularly the brain. this requires peripheral vasoconstriction which necessitates some degree of bradycardia.
On an intentionally long dive, circulation will be shut off to the muscles and viscera from the start of the dive, with profound bradycardia, and the blood oxygen is effectively reserved for the brain. The muscles use the oxygen from myoglobin, then switch to anaerobic metabolism, the same system used by seals on forced dives.
Usually, the seals use an intermediate process, where the most active muscles are shut off from circulation and use locally stored oxygen to avoid compromising the blood oxygen stores, which requires a limited degree of bradycardia to compensate for the increased peripheral vascular restriction, which makes attempts to calculate ADL impracticable, even if the available oxygen stores are accurately assessed.
Eared seals
An eared seal is any member of the marine mammal family Otariidae, one of three groupings of pinnipeds. They comprise 15 extant species in seven genera and are commonly known either as sea lions or fur seals, distinct from true seals (phocids) and the walrus (odobenids). Otariids are adapted to a semiaquatic lifestyle, feeding and migrating in the water, but breeding and resting on land or ice.
Otariids have proportionately much larger foreflippers and pectoral muscles than phocids and have the ability to turn their hind limbs forward and walk on all fours, making them far more manoeuvrable on land. They are generally considered to be less adapted to an aquatic lifestyle since they breed primarily on land and haul out more frequently than true seals. However, they can attain higher bursts of speed and have greater manoeuvrability in the water. Their swimming power derives from the use of flippers more so than the sinuous whole-body movements typical of phocids and walruses.
Otariids are carnivorous, feeding on fish, cephalopods and krill. Sea lions tend to feed closer to shore in upwelling zones, feeding on larger fish, while the smaller fur seals tend to take longer, offshore foraging trips and can subsist on large numbers of smaller prey items. They are visual feeders. Some females are capable of dives of up to 400 m (1,300 ft) depth.
Walrus
The walrus (Odobenus rosmarus) is a large flippered marine mammal from the Arctic Ocean and subarctic seas of the Northern Hemisphere. Adult walrus are characterised by prominent tusks and whiskers, and their considerable bulk: adult males in the Pacific can weigh more than
Walruses prefer shallow shelf regions and forage primarily on the seafloor, often from sea ice platforms. They are not particularly deep divers compared to other pinnipeds; their deepest recorded dives are around 80 m (260 ft). They can remain submerged for as long as half an hour.
Cetaceans
The cetaceans are an infraorder of obligate aquatic mammals with 93 living species, in two parvorders. The Odontoceti, or toothed whales, are 73 species, including the dolphins, porpoises, beluga whale, narwhal, sperm whale, and beaked whales. The Mysticeti, or baleen whales, have a filter-feeding system, are fifteen species in three families, and include the blue whale, right whales, bowhead whale, humpback whale rorqual, and gray whale.
The wide range of body mass in cetaceans has a significant influence on the capacity for oxygen storage and use, which affects dive limits. The myoglobin content of the skeletal muscles varies considerably between species and is strongly correlated to the maximum diving duration on toothed whales. The combined effects of body mass and myoglobin content was found to account for 50% of the overall variation in cetacean diving performance and 83% of the variation in odontocete diving performance.
Beaked whales
The family of beaked whales includes some very cryptic and inaccessible animals, and they are considered to be deep-diving foragers mainly based on stomach contents. Tagging studies by Hooker and Baird, (1999) show that the northern bottlenose whale, Hyperoodon ampullatus, is capable of diving to depths more than 1500 m with durations of over an hour. Johnson et al., (2004) used acoustic recording tags to record echolocation clicks produced by Cuvier's beaked whale (Ziphius cavirostris) and Blainville's beaked whales (Mesoplodon densirostris) during dives of up to 1270 m depth, indicating that they use a series of regular clicks with occasional fast buzzing sequences during deep dives. It was concluded that both these species forage in deep water using echolocation.
Beaked whales, Ziphius cavirostris and Mesoplodon densirostris have been observed in natural circumstances to hunt in deep water by echolocation – Z. cavirostris to depths up to 1885 metres for durations up to 58 minutes. These deep foraging dives were in each case followed by a series of much shallower dives with no indications of foraging behaviour. The interval between foraging dives was long enough to indicate the high probability of recovery from an oxygen debt incurred by anaerobic metabolism. The foraging dives duration exceeded estimated aerobic dive limits by a factor in the order of two times. Reports of gas emboli in stranded beaked whales associated with naval sonar exercises have led to hypotheses that their diving profiles may make them vulnerable to decompression sickness, possibly exacerbated by high energy sonar pulses. The current models of breath-hold diving do not adequately explain the natural diving behaviour of these whales.
In beaked whales, the descent rate was consistently faster than ascent rate, at about 1.5 metres per second, regardless of dive depth, and at a steep angle of from 60 to 85 degrees, Fluke rate for Z cavirostris was higher at the start of the dive, but reduced by about 50 m depth, with a constant descent rate, consistent with buoyancy reduction due to lung compression.
Ascents from deep foraging dives were at a low vertical speed averaging 0.7 metres per second at a low angle. Mesoplodon ascent rates varied with dive depth, with a faster ascent associated with deeper dives giving a relatively constant overall ascent time. For Ziphius, the ascent strategy is unclear: they tend to ascend rapidly in the first few hundred meters from deeper dives then slow down around 500 m and speed up again near the surface. Both species began their ascent faster from deeper dives, but there was no clear correlation apparent between ascent speed and dive depth in the top 200 m of the ascent.
Fluke rate in both species for the last 40 m of the ascent was much lower than during descents which is consistent with the hypothesis that the final part of the ascent is largely powered by the buoyancy force of air expanding in the lungs.
Both Ziphius cavirostris and Mesoplodon densirostris, make long, deep dives to feed on a deep water source. Diving follows a distinct pattern with most deep foraging dives followed by a closely timed series of shallow dives and recovery near the surface. All foraging dives in these species appear to be much longer than the estimated aerobic dive limits, indicating that the whales generally return to the surface from them with an oxygen debt. It has been hypothesised that the series of shallow dives and the long periods between foraging dives are needed to recover from the oxygen debt in preparation for the next deep dive. The long intervals spent near the surface are considered to be inconsistent with the hypothesis that beaked whales are chronically supersaturated at high levels.
The similar times of descent and ascent of the shallow post-foraging dives do not appear to be consistent with requirements for recompression. The relatively slow ascents from foraging dives are not adequately explained. These ascents involve active swimming and no feeding, with the lowest ascent rate occurring below the depth of lung collapse, which does not seem likely to help prevent bubble formation, and by current models of nitrogen diffusion, may increase the risk of decompression sickness.
Analysis by Tyack et al. (2006) does not suggest that the beaked whales run a risk of decompression stress and embolism during normal diving behaviour. Houser et al. (2001) modelled nitrogen levels in the tissues of a diving bottlenose whale assuming lung collapse at a depth of 70 m and found that diving speed and depth are the main factors influencing tissue nitrogen accumulation. Dives with longer times at depths where the lungs were incompletely collapsed allowed greater in gassing and supersaturation. The in gassing rate of nitrogen depends on both the alveolar area exposed to the gas, which decreases with depth as the lungs progressively collapse, and the partial pressure gradient which increases linearly with depth, and is estimated to reach a maximum about halfway between the surface and the depth of complete alveolar collapse.
Sperm whale
The sperm whale (Physeter macrocephalus) is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus Physeter and one of three extant species in the sperm whale family, along with the pygmy sperm whale and dwarf sperm whale of the genus Kogia.
The sperm whale respiratory system has adapted to cope with drastic pressure changes when diving. The flexible ribcage allows lung collapse, reducing nitrogen intake, and metabolism can decrease to conserve oxygen. Between dives, the sperm whale surfaces to breathe for about eight minutes before diving again. Odontoceti (toothed whales) breathe air at the surface through a single, S-shaped blowhole, which is extremely skewed to the left. Sperm whales spout (breathe) 3–5 times per minute at rest, increasing to 6–7 times per minute after a dive. The blow is a noisy, single-stream that rises to or more above the surface and points forward and left at a 45° angle. On average, females and juveniles blow every 12.5 seconds before dives, while large males blow every 17.5 seconds before dives. A sperm whale killed south of Durban, South Africa, after a 1-hour, 50-minute dive was found with two dogfish (Scymnodon sp.), usually found at the sea floor, in its belly.
In 1959, the heart of a 22 metric-ton (24 short-ton) male taken by whalers was measured to be , about 0.5% of its total mass. The circulatory system has a number of specific adaptations for the aquatic environment. The diameter of the aortic arch increases as it leaves the heart. This bulbous expansion acts as a windkessel, a hydraulic accumulator, ensuring a steady blood flow as the heart rate slows during diving. The arteries that leave the aortic arch are positioned symmetrically. There is no costocervical artery. There is no direct connection between the internal carotid artery and the vessels of the brain. Their circulatory system has adapted to dive at great depths, as much as for up to 120 minutes, with the longest recorded dive being 138 minutes long. More typical dives are around and 35 minutes in duration. Myoglobin, which stores oxygen in muscle tissue, is much more abundant than in terrestrial animals. The blood has a high density of red blood cells, which contain oxygen-carrying haemoglobin. The oxygenated blood can be directed towards only the brain and other essential organs when oxygen levels deplete. The spermaceti organ may also play a role by adjusting buoyancy. The arterial retia mirabilia are extraordinarily well-developed. The complex arterial retia mirabilia of the sperm whale are more extensive and larger than those of any other cetacean.
Dolphins
Dolphin is a common name for aquatic mammals within the infraorder Cetacea. The term dolphin usually refers to the extant families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), and Pontoporiidae (the brackish dolphins), and the extinct Lipotidae (baiji or Chinese river dolphin). There are 40 extant species named as dolphins.
Dolphins range in size from the long and Maui's dolphin to the and killer whale. Several species exhibit sexual dimorphism, in that the males are larger than females. They have streamlined bodies and two limbs that are modified into flippers. Though not quite as flexible as seals, some dolphins can travel at . Dolphins use their conical shaped teeth to capture fast-moving prey. They have well-developed hearing which is adapted for both air and water and is so well developed that some can survive even if they are blind. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water. The thickness of the blubber layer can be limited by buoyancy constraints, as better insulation by a thicker layer of blubber can make the animal more buoyant than optimum for the energy costs of diving. This effect is more pronounced on smaller animals and juveniles where the surface area to volume ratio is greater.
Diving behaviour
The short-beaked common dolphin (Delphinus delphis) is known to forage at depths up to 260 m for 8 minutes or more, but mostly stays above 90 m for dives of about 5 minutes duration. The pantropical spotted dolphin (Stenella attenuata) can dive to at least 170 m, but most dives are between 50 and 100 m for between 2 and 4 minutes.
The long-finned pilot whale (Globicephalas melas) can dive to between 500 and 600 m for up to 16 minutes. Northern bottlenose whales dive to the seabed at 500 to 1500 m for more than 30 minutes, occasionally as long as 2 hours.
White whales (Delphinapterus leucas) frequently dive to depths between 400 and 700 m, with the deepest at 872 m. for an average duration of 13 minutes and maximum of 23 minutes, and with dive duration increasing with body size. Narwhals (Monodon monoceros) routinely dive to 500 m, and occasionally to 1000m or more, but mostly shallower.
In free-dives to depths of 60 m and 210 m, bottlenose dolphin heart rates dropped from a pre-dive average of 101–111 bpm to 20–30 bpm within 1 min of the start of the descent and averaged 37 and 30 bpm during the bottom phases the 60 m and 210 m dives. The dolphins' heart rates increased during ascent. The heart rates during a dive of these actively swimming dolphins were similar to heart rates of a sedentary dolphin at 2 m depth, showing that the heart rate response in diving dolphins is dominated by the diving response and not by an exercise response. During the final ascent, heart rates increased while fluke stroke rates decreased during periods of prolonged gliding towards the end of the dive. Lack of evidence for an exercise response does not necessarily imply that there is no muscle perfusion during diving, as earlier studies indicate elevated post-dive muscle nitrogen levels.
Baleen whales
Baleen whales, (systematic name Mysticeti, form a parvorder of the Cetacea. They are a widely distributed group of carnivorous marine mammals of the families Balaenidae (right and bowhead whales), Balaenopteridae (rorquals), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the gray whale). There are currently 15 species of baleen whales. Baleen whales range in size from the and pygmy right whale to the and blue whale.
When swimming, baleen whales use their forelimb flippers in a wing-like manner similar to penguins and sea turtles for locomotion and steering, while using their tail fluke to propel themselves forward through repeated vertical motion. Because of their great size, right whales are not flexible or agile like dolphins, and none can move their neck because of the fused cervical vertebrae; this sacrifices speed for stability in the water. The vestigial hind legs are enclosed inside the body.
Rorquals need to build speed to feed, and have several adaptions for reducing drag, including a streamlined body; a small dorsal fin, relative to its size; and lack of external ears or hair. The fin whale, the fastest among baleen whales, can travel at . While feeding, the rorqual mouth expands by stretching the throat pleats to a volume that can be bigger than the resting whale itself; The mandible is connected to the skull by dense fibres and cartilage (fibrocartilage), allowing the jaw to swing open at almost a 90° angle. The mandibular symphysis is also fibrocartilaginous, allowing the jaw to bend which increases the area of the opening. To prevent stretching the mouth too far, rorquals have a sensory organ located in the middle of the jaw to regulate these functions.
Like all mammals, baleen whales breathe air and must surface periodically to do so. Their nostrils, or blowholes, are situated at the top of the cranium. Baleen whales have two blowholes, as opposed to toothed whales which have one. These paired blowholes are longitudinal slits that converge anteriorly and widen posteriorly, which causes a V-shaped blow. They are surrounded by a fleshy ridge that keeps water away while the whale breathes. The septum that separates the blowholes has two plugs attached to it, making the blowholes water-tight while the whale dives.
The lungs of baleen whales are built to collapse under pressure. enabling some, like the fin whale, to dive to a depth of . The whale lungs are very efficient at extracting oxygen from the air, usually 80%, whereas humans only extract 20% of oxygen from inhaled air. Lung volume is relatively low compared to terrestrial mammals because of the inability of the respiratory tract to hold gas while diving. Doing so may cause serious complications such as embolism. Unlike other mammals, the lungs of baleen whales lack lobes and are more sacculated. The left lung is smaller than the right to make room for the heart. To conserve oxygen, blood is rerouted from hypoxia-tolerant-tissue to essential organs, and the skeletal muscles have a high concentration of myoglobin which allows them to function for longer without a blood oxygen supply.
The heart of baleen whales functions similarly to other mammals, and is proportional to the whale's size. The resting heart rate is 60 to 140 beats per minute (bpm). When diving, the heart rate will drop to 4 to 15 bpm to conserve oxygen. Like toothed whales, they have a dense network of blood vessels (rete mirabile) which prevents heat-loss. Like in most mammals, heat is lost in their extremities, so, the arteries are surrounded by veins to reduce heat loss during transport and recover heat transferred from the arteries to the surrounding veins as it travels back into the core in countercurrent exchange. To counteract overheating while in warmer waters, baleen whales reroute blood to the skin to accelerate heat-loss. They have the largest blood corpuscles (red and white blood cells) of any mammal, measuring in diameter.
Unlike most animals, whales are conscious breathers. All mammals sleep, but whales cannot afford to become unconscious for long because they may drown. They are believed to exhibit unihemispheric slow-wave sleep, in which they sleep with half of the brain while the other half remains active. This behaviour was only documented in toothed whales until footage of a humpback whale sleeping (vertically) was shot in 2014.
It is largely unknown how baleen whales produce sound because of the lack of a melon and vocal cords. In a 2007 study, it was discovered that the larynx had U-shaped folds which are thought to be similar to vocal cords. They are positioned parallel to airflow, as opposed to the perpendicular vocal cords of terrestrial mammals. These may control airflow and cause vibrations. The walls of the larynx can contract which may generate sound with support from the arytenoid cartilages. The muscles surrounding the larynx may expel air rapidly or maintain a constant volume while diving.
All modern mysticetes are obligate filter feeders, using their baleen to strain small prey items (including small fish, krill, copepods, and zooplankton) from seawater. Despite their carnivorous diet, a 2015 study revealed they house gut flora similar to that of terrestrial herbivores. Different kinds of prey are found in different abundances depending on location, and each type of whale is adapted to a specialized way of foraging.
There are two types of feeding behaviours: skim-feeding and lunge-feeding, but some species do both depending on the type and amount of food. Lunge-feeders feed primarily on euphausiids (krill), though some smaller lunge feeders (e.g. minke whales) also prey on schools of fish. Skim-feeders, like bowhead whales, feed upon primarily smaller plankton such as copepods. They feed alone or in small groups. Baleen whales get the water they need from their food, and their kidneys excrete excess salt.
The lunge-feeders are the rorquals. To feed, lunge-feeders expand the volume of their jaw to a volume bigger than the original volume of the whale itself. To do this, the mouth inflates, which causes the throat pleats to expand, increasing the amount of water that the mouth can store. Just before they ram the baitball, the jaw swings open at almost a 90° angle and bends which lets in more water. To prevent stretching the mouth too far, rorquals have a sensory organ located in the middle of the jaw to regulate these functions. Then they must decelerate. This process takes a lot of mechanical work, and is only energy-effective when used against a large baitball. Lunge feeding is more energy-intensive than skim-feeding due to the acceleration and deceleration required.
The skim-feeders are right whales, grey whales, pygmy right whales, and sei whales (which also lunge feed). To feed, skim-feeders swim with an open mouth, filling it with water and prey. Prey must occur in sufficient numbers to trigger the whale's interest, be within a certain size range so that the baleen plates can filter it, and be slow enough so that it cannot escape. The "skimming" may take place on the surface, underwater, or even at the ocean's bottom, indicated by mud occasionally observed on right whales' bodies. Gray whales feed primarily on the ocean's bottom, feeding on benthic creatures.
Foraging efficiency for both lunge feeding and continuous ram filter feeding is highly dependent upon prey density. The efficiency of a blue whale lunge is approximately 30 times higher at krill densities of 4.5 kg/m3 than at low krill densities of 0.15 kg/m3. Baleen whale have been observed seeking out highly specific areas within the local environment in order to forage at the highest density prey aggregations.
Sirenians
Sirenians are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The Sirenia currently comprise the families Dugongidae (the dugong and, historically, Steller's sea cow) and Trichechidae (manatees) with a total of four species.
The tail fluke of a dugong is notched and similar to those of dolphins, whereas the tail fluke of manatees is paddle-shaped. The fluke is moved up and down in long strokes to move the animal forward, or twisted to turn. The forelimbs are paddle-like flippers that aid in turning and slowing. Manatees generally glide at speeds of , but can reach speeds of in short bursts. The body is fusiform to reduce drag in the water. Like cetaceans, the hind limbs are internal and vestigial. The snout is angled downwards to aid in bottom-feeding. Sirenians typically make two- to three-minute dives, but manatees can hold their breath for up to 15 minutes while resting and dugongs up to six minutes. They may stand on their tail to hold their head above water.
Sirenians exhibit pachyostosis, a condition in which the ribs and other long bones are solid and contain little or no bone marrow. They have among the densest bones in the animal kingdom, which may be used as ballast, counteracting the buoyancy effect of their blubber and help keep sirenians suspended slightly below the water's surface. Manatees do not possess blubber, per se, but rather have thick skin, and, consequently, are sensitive to temperature changes. Likewise, they often migrate to warmer waters whenever the water temperature dips below . The lungs of sirenians are unlobed; they, along with the diaphragm, extend the entire length of the vertebral column, which help them control their buoyancy and reduce tipping in the water.
The body of sirenians is sparsely covered in short hair (vibrissae), except for on the muzzle, which may allow for tactile interpretation of their environment.
Carnivorans
The sea otter hunts in short dives, often to the sea floor. Although it can hold its breath for up to five minutes, its dives typically last about one minute and not more than four. It is the only marine animal capable of lifting and turning over rocks, which it often does with its front paws when searching for prey. The sea otter may also pluck snails and other organisms from kelp and dig deep into underwater mud for clams. It is the only marine mammal that catches fish with its forepaws rather than with its teeth.
Under each foreleg, the sea otter has a loose pouch of skin that extends across the chest. In this pouch (preferentially the left one), the animal stores collected food to bring to the surface. This pouch also holds a rock, unique to the otter, that is used to break open shellfish and clams. There, the sea otter eats while floating on its back, using its forepaws to tear food apart and bring it to its mouth. It can chew and swallow small mussels with their shells, whereas large mussel shells may be twisted apart. It uses its lower incisor teeth to access the meat in shellfish.
To eat large sea urchins, which are mostly covered with spines, the sea otter bites through the underside where the spines are shortest and licks the soft contents out of the urchin's shell.
The sea otter's use of rocks when hunting and feeding makes it one of the few mammal species to use tools. To open hard shells, it may pound its prey with both paws against a rock on its chest. To pry an abalone off its rock, it hammers the abalone shell using a large stone, with observed rates of 45 blows in 15 seconds. Releasing an abalone, which can cling to rock with a force equal to 4,000 times its own body weight, requires multiple dives.
Polar bears can swim long distances at sea and can dive for short periods. Researchers tracked polar bears with GPS system collarsand recorded long-distance swims up to , with an average of , taking up to ten days. A polar bear may swim underwater for up to three minutes to approach seals on shore or on ice floes while hunting.
Diving birds
Aquatic birds are secondarily adapted to live and forage in water.
Diving birds plunge into the water to catch their food. They may enter the water from the flight, as does the brown pelican and the gannet, or they may dive from the surface of the water. Some diving birds – for example, the extinct Hesperornithes of the Cretaceous Period – propelled themselves with their feet. They were large, streamlined, flightless birds with teeth for grasping slippery prey. Today, cormorants, loons, and grebes are the major groups of foot-propelled diving birds. Other diving birds are wing-propelled, most notably the penguins, dippers and auks.
Rapid onset bradycardia has been observed in diving birds during forced submersion, including penguins, cormorants, guillemots, puffins, and rhinoceros auklets. Perfusion of organs during bradycardia and peripheral vasoconstriction in forced submersions of ducks has shown similar findings to seals, confirming redistribution of blood flow to essentially the brain, heart, and adrenal glands. Heart rate during a free dive decreases from the pre-dive level but does not usually drop below the resting heart rate.
In free-diving cormorants, heart rate dropped at the start of the dive, and usually stabilized at depth, but increased again at the start of the ascent, with average heart rates during the dive much the same as at rest, but the variation in heart rate and vasoconstriction varies considerably between species, and true bradycardia occurs in emperor penguins on long-duration dives.
Birds display complex cardiovascular responses during free dives. Flighted diving birds with large respiratory oxygen reserves and low myoglobin concentrations tend to retain relatively high heart rates during dives, with a predominant exercise response for muscle perfusion. In more extreme dives a more classic diving response may occur with decreased heart rates and increased peripheral vasoconstriction. In penguins, which have smaller respiratory oxygen reserves but much larger myoglobin concentrations, heart rates during dives start high but progressively decline as dive duration increases. This high heart rate early in the dive continues gas exchange with the respiratory oxygen reserves. In emperor penguins, perfusion may be variable at the start of a dive, and muscle may or may not be perfused. Arterial-venous shunts may be opened to allow venous blood oxygen storage. Extremely low heart rates at the deepest part of the dive should limit nitrogen absorption, conserve blood oxygen, and increase aerobic muscle metabolism based on myoglobin-bound oxygen reserves.
Aquatic birds have to overcome the drag created between their bodies and the surrounding water while swimming at the surface or underwater. At the surface, the wave-making resistance will increase substantially when the speed exceeds hull speed, when the bow wavelength equals the length of the body in the water, so surface swimming bird seldom exceeds this speed. Wave making resistance dissipates with depth below the surface, making underwater swimming much less energy-intensive for well-streamlined diving animals.
About 60% of the diving effort of ducks is used to overcome buoyancy and 85% of the effort to remain at depth. About half of the air trapped in their feathers is lost. Birds that dive deeper tend to trap less air in the plumage, reducing their potential buoyancy, but this also represents a loss of thermal insulation, which can be compensated by subcutaneous fat, which increases body mass and thereby the energy cost of the flight. Penguins avoid this problem by having lost the power of flight, and are the densest of birds, with solid bones, short, closely packed feathers, and a substantial layer of subcutaneous fat, reducing diving effort expended against buoyancy. The reciprocating drag-based foot-propulsion in diving birds is less efficient than flapping of flipper-form wings, which produce thrust on both up and down-stroke.
Penguins
Emperor penguins regularly dive to depths of 400 to 500 m for 4 to 5 minutes, often dive for 8 to 12 minutes and have a maximum endurance of about 22 minutes. At these depths the markedly increased pressure would cause barotrauma to air-filled bones typical of birds, but the bones of the penguin are solid, which eliminates the risk of mechanical barotrauma on the bones.
While diving, the emperor penguin's oxygen use is markedly reduced, as its heart rate is reduced to as low as 15–20 beats per minute and non-essential organs are shut down, thus facilitating longer dives. Its haemoglobin and myoglobin can bind and transport oxygen at low blood concentrations; this allows the bird to function with very low oxygen levels that would otherwise result in loss of consciousness.
The energy costs of swimming at the surface and swimming underwater of penguins are lower than that of the more buoyant, less streamlined, and less propulsively efficient ducks, which swim on the surface using their webbed feet as paddles, whereas penguins swim just below the surface using their wings as hydrofoils. The energy cost of transport of a given mass of birds for a given horizontal distance at the surface is about three times greater for ducks than penguins. Ducks are very buoyant and the energy expended in overcoming buoyancy and staying at the bottom is the major part of the energy expended in diving. To remain within the calculated aerobic dive limit, the duration of the duck's dive must be short. On the other hand, Gentoo, king and emperor penguins have maximum dive durations between 5 and 16 minutes, and maximum depths from 155 to 530 m, which requires a diving metabolic rate equivalent to resting at the surface to dive within aerobic limits. The internal temperature of king and gentoo penguins drops during dives, which may reduce oxygen requirements.
Aquatic reptiles
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment. Currently, of the approximately 12,000 extant reptile species and subspecies, only about 100 are classed as marine reptiles: extant marine reptiles include marine iguanas, sea snakes, sea turtles and saltwater crocodiles.
The earliest marine reptiles arose in the Permian period during the Paleozoic era. During the Mesozoic era, many groups of reptiles became adapted to life in the seas, including such familiar clades as the ichthyosaurs, plesiosaurs, mosasaurs, nothosaurs, placodonts, sea turtles, thalattosaurs and thalattosuchians. After the mass extinction at the end of the Cretaceous period, marine reptiles were less numerous, but there was still a high variety of species in the early Cenozoic, such as "true" sea turtles, bothremydids, palaeophiid snakes, a few choristoderes such as Simoedosaurus and dyrosaurid crocodylomorphs. Various types of marine gavialid crocodilians remained widespread as recently as the Late Miocene.
Some marine reptiles, such as ichthyosaurs, plesiosaurs, metriorhynchid thalattosuchians, and mosasaurs became so well adapted to a marine lifestyle that they were incapable of venturing onto land and gave birth in the water. Others, such as sea turtles and saltwater crocodiles, return to shore to lay their eggs. Some marine reptiles also occasionally rest and bask on land. Sea snakes, crocodiles and marine iguanas only dive in inshore waters and seldom dive deeper than 10 m.
Extinct taxa
Few data are available that show exactly how deep plesiosaurs dived. That they dived to some considerable depth is proven by traces of decompression sickness. The heads of the humeri and femora of many fossils show necrosis of the bone tissue, caused by nitrogen bubble formation due to a too rapid ascent after deep diving. However, this does not provide sufficient information to deduce a depth with any accuracy, as the damage could have been caused by a few very deep dives, or by a large number of relatively shallow exposures. The vertebrae show no such damage: they may have been protected by a superior blood supply, made possible by the arteries entering the bone through the two foramina subcentralia, large openings in their undersides.
Descending would have been helped by negative buoyancy, but this would have been a disadvantage when surfacing. Young plesiosaurs show pachyostosis, an extreme density of the bone tissue, which would have decreased buoyancy. Adult individuals have more spongy bones. Gastroliths has been suggested as a method to increase weight or even as a means to attain neutral buoyancy, swallowing or spitting them out again as needed. They might also have been used to increase stability.
Sea turtles
Sea turtles, or marine turtles, are reptiles of the superfamily Chelonioidea, order Testudines and of the suborder Cryptodira. The seven existing species of sea turtles are the green sea turtle, loggerhead sea turtle, Kemp's ridley sea turtle, olive ridley sea turtle, hawksbill sea turtle, flatback sea turtle, and leatherback sea turtle.
As air-breathing reptiles, sea turtles must surface to breathe. They spend most of their time underwater, so must be able to hold their breath for long periods to avoid frequent surfacing. Dive duration largely depends on the activity. A foraging sea turtle may typically spend 5–40 minutes under water while a sleeping sea turtle can remain underwater for 4–7 hours. Sea turtle respiration remains aerobic for the vast majority of voluntary dive time. When a sea turtle is forcibly submerged (e.g. entangled in a trawl net) its diving endurance is substantially reduced, so it is more susceptible to drowning.
When surfacing to breathe, a sea turtle can quickly refill its lungs with a single explosive exhalation and rapid inhalation. Their large lungs permit rapid exchange of oxygen and avoid trapping gases during deep dives. Sea turtle blood can deliver oxygen efficiently to body tissues during diving. During the routine activity, green and loggerhead turtles dive for about four to five minutes, and surface to breathe for one to three seconds.
The deepest diving sea turtle is the leatherback which can reach 1250 m depth, while the record for the longest dive goes to loggerheads (Caretta caretta) in the Mediterranean at more than 10 hours. For many hard-shelled sea turtles, depths visited on average (i.e. outside of overwintering) range from 2–54 m; for leatherbacks, this ranges up to 150 m. The effect of temperature on sea turtles has been explored thoroughly and is shown to influence turtle metabolic rates, circulation and other physiological factors. Therefore, dive behaviour is presumed to shift based on needs for thermoregulation and in response to seasonal changes (longer dives with lower temperatures), although across species and regions the relationship between temperature and diving has differed and was only investigated in 12 of 70 studies reviewed. The review also describes that some turtles change dive behaviour based on whether they are transiting. For example, turtles tend to use shallow waters during transit, with occasional deep dives possibly for resting or foraging en route, with the exception of the leatherback that showed longer and deeper dives during transit. Importantly, dive behaviour differed based on habitat type and geography.
Turtles can rest or sleep underwater for several hours at a time, but submergence time is much shorter while diving for food or to escape predators. Breath-holding ability is affected by activity and stress, which is why turtles quickly drown in shrimp trawlers and other fishing gear. During the night while sleeping and to protect themselves from potential predators, the adults wedge themselves under rocks below the surface and under ledges in reefs and coastal rocks. Many green sea turtles have been observed returning to the same sleeping location over successive nights.
Leatherback
The leatherback turtle Dermochelys coriacea is the deepest diving extant reptile. The dive profile is consistent, with an initial phase of fairly steep downward swimming at about a 40° descent angle, stroking at about once in 3 seconds with the flippers, followed by a gliding phase, which starts at a depth that varies with the maximum depth of the dive, suggesting that the inspired air volume is chosen depending on how deep the turtle intends to dive, similarly to hard-shelled turtles and penguins. During ascent, the turtles actively swim at a similar stroke rate, but at a lower pitch angle of about 26°, giving a fairly low ascent rate of about 0.4 m/s, or 24 m/min. This may be a strategy to avoid decompression sickness. The relatively low body temperature is conjectured to help reduce the risk of bubble formation by providing a higher solubility of nitrogen in the blood.
Some marine mammals reduce the risk of decompression sickness and nitrogen narcosis by limiting the amount of air in the lungs during a dive, basically exhaling before the dive, but this limits the oxygen available from lung contents. As dive endurance is proportional to available oxygen, this strategy limits dive duration, and some animals inhale before diving. This increases decompression risk, and this may be behaviourally mitigated by limiting the ascent rate or spending fairly long periods at or near the surface to equilibrate between dives. The amount of air in the lungs at the start of the dive also influences buoyancy, and achieving near neutral buoyancy during the bottom phase may reduce the overall energy requirement of the dive.
Green turtles
Okuyama et al. (2014) found that green turtles Chelonia mydas maximised their submerged time, but changed their dive strategy depending on whether they were resting or foraging. They surfaced without depleting estimated oxygen reserves, followed by a few breaths to recover. Optimal foraging behaviour does not always completely use up the available stored oxygen. Termination of a shallow dive relatively early if no food is encountered could be energy efficient over long periods for animals that habitually spend more time submerged and only surface briefly to exchange gas, which is the case with turtles. Such "surfacers" are assumed to also maximize other benefits of their dives besides foraging, such as resting, mating and migration.
Sea turtles are ectothermic and have physiological functions well adapted for prolonged dives, in that their metabolism is significantly slower than that of diving birds and mammals, but their metabolism is not constant and is affected by water temperature and exertion. Voluntary dives are started with near saturation levels of oxygen and finished near depletion. Their lungs are highly elastic and reinforced, with a high oxygen diffusion capacity, allowing short surface breathing intervals. Respiration frequency depends on water temperature and the oxygen consumption of the previous dive. Turtles adjust the volume of inspired air to suit the buoyancy needs to be anticipated for each dive.
These turtles take more breaths after resting dives than after foraging and other dives. After resting dives, turtles surface with nearly depleted oxygen reserves but do not exceed the aerobic dive limit. They then start the next dive with saturated oxygen content, although the lung volume changes with the anticipated dive depth. This procedure allows them to maximise submerged time, reducing surfacing effort.
The tidal volume varies little between active and resting turtles, and does not appear to be affected by exertion and water temperature. Turtles appear to replenish their oxygen content to the saturation level before a dive but do not usually use all the available oxygen in foraging and other dives, so fewer breaths are needed for replenishment in comparison with resting dives.
Green turtles feed on seagrass in shallow water, generally less than 3 m deep, while most other dives occur during travel between the feeding ground and the resting place. During travel, turtles breathe while swimming, usually just one breath before submerging again. Surface swimming causes wave-making drag, and the animal must hold its head up in the air while breathing, causing more drag. Taking a single breath between dives while travelling appears to be energy efficient.
Decompression sickness
Under the pressure of diving, lung gases in vertebrates diffuse into the pulmonary blood circulation and are carried to other tissues where they diffuse further according to gas tension gradients and perfusion rates. Ambient pressure increases with depth, so the amount of nitrogen that is absorbed by the blood and tissues increases also increases, producing higher dissolved gas tensions that would reach equilibrium with the partial pressure of nitrogen in the lungs given sufficient time. This problem has long been recognised for human divers breathing air at ambient pressure, but has not been considered to be a problem for breath-hold divers as they only have the air of a single inhalation per dive. For free-diving animals which can dive significantly deeper and for considerably longer, tissues can become relatively highly saturated depending on the process of loading during diving and washout between dives at the surface. During ascent, if the dissolved nitrogen in the tissues cannot diffuse back into the residual lung gas fast enough with the reducing pressure, tissues may become supersaturated, with potential for gas-bubble formation. Although small bubbles can form without apparent injury, the formation and growth of bubbles is generally considered a characteristic event in the development of decompression sickness.
Observations and theoretical modelling suggest that even in normal diving conditions, at least some marine mammals may have some nitrogen tissue supersaturation at the surface at times, implying that their diving adaptations are either insufficient or are not fully exploited, leading to questions of what causes this supersaturation, and whether it is a significant health threat.
History
Originally, the study of diving was limited to observation of the behaviour from the surface. Since the 1930s experimental work provided insights into how air-breathing animals dive. and more recently, as remote sensing and recording methods such as sonar, capillary tubes, and microprocessor-controlled time and depth recorders (TDRs) and satellite-linked TDRs became available, the study of diving has expanded and diversified. The improved instrumentation has made more accurate and precise measurements of diving behaviour possible on a wide range of diving animals.
References
Animal physiology | Physiology of underwater diving | [
"Biology"
] | 15,141 | [
"Animals",
"Animal physiology"
] |
63,196,821 | https://en.wikipedia.org/wiki/Pierre%20Peytier | Pierre Peytier - Jean Pierre Eugène Félicien Peytier (15 October 17931864), sometimes named Eugène Peytier - was a French officer, geographer, engineer, cartographer and painter.
Life
Pierre Peytier entered the École polytechnique in 1811, where he obtained his diploma (X1811). He was then integrated into the topographical service of the French army in the corps of the engineers-geographers in 1813. He was promoted lieutenant in 1817, then capitain in 1827.
In the Pyrenees (1825)
Engineer geographer and geodesist, he was one of the first geodesic officers charged in 1825 with the triangulation of the Pyrenees in order to establish the map of France, together with his colleague Paul-Michel Hossard. By necessity of service and together with the officers Corabœuf and Testuhe, he was also one of the first pyreneists.
He made the first ascents of the Pyrenean peaks Palas, Balaïtous and Saint-Barthélemy. These true exploits went completely unnoticed at the time and many later ascensionists, believing they were achieving these ascents first, found traces of the passage of the Geodesists. That was the case for the explorer Charles Packe when reaching the summit of the Balaïtous.
Scientific expedition of Morea (1829)
Captain Pierre Peytier, of the topographic service of the French army, had already been invited to Greece by its Governor Ioannis Kapodistrias when the latter had come to Paris in October 1827 to ask the French government for advisers and officers of the army French to organize the army of the newly founded Greek State (during the Greek War of Independence). Thus, on the recommendation of the French Ministry of War, Peytier and three other officers arrived in Greece, in order to train young Greek engineers who would undertake surveying projects, while Peytier himself was to draw the plans for the city of Corinth and the map of Peloponnese. Then when the scientific expedition of Morea landed at Navarino in the Peloponnese on 3 March 1829, Peytier was thus attached to it.
As soon as from March, a base of 3,500 meters had been traced in the Argolis, from one angle at the ruins of Tiryns to an angle of a house in ruins in the village of Aria. This was intended to serve as a point of departure in all the triangulation operations for topographic and geodesic readings in the Peloponnese. Peytier and Puillon-Boblaye proceeded to perform numerous verifications on the base and on the rulers used. The margin of error was thus reduced to 1 meter for every 15 kilometers. The longitude and latitude of the base point at Tiryns were read and checked, so that again the margin of error was reduced as far as possible to an estimated 0.2 seconds. 134 geodesic stations were set up on the peninsula's mountains, as well as on Aegina, Hydra and Nafplion. Thus, equilateral triangles whose sides measured about were drawn. The angles were measured with Gambey's theodolites. However, after the departure of the scientific mission from Greece, and although he fell ill with the fever five times, Peytier remained there alone until 31 July 1831 to complete the trigonometric, topographic and statistical work for the establishment of the map of Morea.
This « Map of 1832 », very precise, drawn at a 1/200,000 scale, over 6 sheets (plus two sheets depicting some of the islands of the Cyclades) was the first map of the Greek territory ever constructed scientifically and geodesically. After a passage in France between 1831 and 1833, Peytier returned to Greece on 28 March 1833 and remained there until March 1836 to direct most of the work for the preparation of the complete map of the Kingdom of Greece at that time. This « Map of 1852 » was definitively published under his direction in 1852.
Peytier also left an album which he himself composed with his pencil drawings, sepias and watercolours depicting city views, monuments, costumes and inhabitants of Greece at the time. He used an artistic style that avoided idealization for the benefit of scientific fidelity and precision, which fully revealed the topographer that he was.
The last years
Peytier returned definitively to France in 1836 and from 1839 he continued his work on the map of France in the cartographic section of the army. He became director of the war archives. He was promoted to the rank of colonel in 1852. He died in 1864 at the age of seventy.
Gallery of drawings
Bibliography
Henri Beraldi, Cent ans aux Pyrénées, Paris, 1898–1904, sept volumes in-8°. Rééditions par « Les Amis du Livre Pyrénéen », Pau, 1977, puis par la « Librairie des Pyrénées et de Gascogne », Pau, 2001.
Yiannis Saïtas et coll., L'œuvre de l'expédition scientifique de Morée 1829-1838, Edited by Yiannis Saïtas, Editions Melissa, 2011 (1re Partie) - 2017 (2nde Partie).
Pierre Peytier, Émile Puillon Boblaye, Aristide-Camille Servier, Notice sur les opérations géodésiques exécutées en Morée, en 1829 et 1830, par MM.Peytier, Puillon-Boblaye et Servier ; suivie d’un catalogue des positions géographiques des principaux points déterminés par ces opérations (Gallica - BnF), Bulletin de la Société de géographie, v. 19 n°117–122 (Janvier – Juin 1833)
Pierre Peytier, The Peytier Album, Liberated Greece and the Morea Scientific Expedition, in the Stephen Vagliano Collection, publié par la Banque Nationale de Grèce, Athènes, 1971.
References
École Polytechnique alumni
1864 deaths
People from Ardèche
Geodesy
French cartographers
French geographers
Pyrénéistes
1793 births | Pierre Peytier | [
"Mathematics"
] | 1,283 | [
"Applied mathematics",
"Geodesy"
] |
63,197,841 | https://en.wikipedia.org/wiki/Timeline%20of%20bordism | This is a timeline of bordism, a topological theory based on the concept of the boundary of a manifold. For context see timeline of manifolds. Jean Dieudonné wrote that cobordism returns to the attempt in 1895 to define homology theory using only (smooth) manifolds.
Integral theorems
Cohomology
Homotopy theory
Notes
Algebraic topology
Differential topology
Bordism | Timeline of bordism | [
"Mathematics"
] | 80 | [
"Fields of abstract algebra",
"Topology",
"Differential topology",
"Algebraic topology"
] |
63,198,540 | https://en.wikipedia.org/wiki/Samsung%20Galaxy%20A71 | The Samsung Galaxy A71 is an Android smartphone designed, developed, marketed, and manufactured by Samsung Electronics as part of its sixth-generation Galaxy A series.
The A71 line consists of SM-A715F/DS, SM-A715F/DSN and SM-A715F/DSM. Key upgrades over the previous model, the Samsung Galaxy A70, include the Android 10 operating system, the Qualcomm Snapdragon 730 chipset, and the camera system. It was announced in December 2019 and released in January 2020.
The phone has a Super AMOLED Plus FHD+ 6.7" display, a 64 MP wide, 12 MP ultrawide, 5 MP depth, and 5 MP macro camera, a 4500 mAh battery, and an under display optical fingerprint scanner.
The Samsung Galaxy A71 5G was a standard 5G variant of the phone. It was introduced in April 2020, sharing the same dimensions as the Samsung Galaxy A71s 5G UW. The Samsung Galaxy A71 5G UW was another variant from July 2020. There's also a 5G variant that released at South Korea in May 2020, called Samsung Galaxy A Quantum, with some differences to the standard Galaxy A71 5G, and its release date is just before the standard 5G variant.
Specifications
Hardware
The Galaxy A71 has a 6.7 " Super AMOLED Plus Infinity O display with an FHD+ 1080x2400 resolution with a 20:9 aspect ratio and a ~393 ppi density with Corning Gorilla Glass 3. The phone itself measures x x and weighs whereas the 5G variant measures 162.5 mm (6.40 in) x 75.5 mm (2.97 in) x 8.1 mm (0.32 in) and weighs 185 g (6.5 oz). The phone is powered by a Qualcomm Snapdragon 730 (8 nm) octa-core (2x2.2 GHz Kryo 470 Gold & 6x1.8 GHz Kryo 470 Silver) chip and an Adreno 618 GPU. The 5G variant is powered by an Exynos 980 (8 nm) octa-core (2x2.2 GHz Cortex-A77 & 6x1.8 GHz Cortex-A55) alongside a Mali-G76 MP5 GPU, and the 5G UW variant is powered by a Qualcomm Snapdragon 765G (7 nm) octa-core (1x2.4 GHz Kryo 475 Prime & 1x2.2 GHz Kryo 475 Gold & 6x1.8 GHz Kryo 475 Silver) and an Adreno 620 GPU. The phone comes with either 6GB or 8GB RAM as well as 128GB internal storage, which can be expanded via a microSD card of up to 512GB. It comes with a non-removable 4500mAh lithium polymer battery which charges with a 25W Super Fast Charger. It also has an in-display optical fingerprint sensor.
Cameras
The Samsung Galaxy A71 has a four-camera setup arranged in an "L" shape located in the corner with a rectangular protrusion similar to that of the iPhone 11 and the Pixel 4. The array consists of a 9 MP wide angle camera, a 9 MP ultrawide camera, a 5 MP macro camera, and a 5 MP depth sensor. It also has a single 32 MP front-facing camera, which sits in a small punch hole on the front of the screen. The rear-facing cameras can record video up to 4K in 30 fps, as well as 1080p in 30, 240, and 960 fps. The front cameras can shoot 1080p at 30 fps. The rear cameras also have Super Steady EIS.
Software
The Galaxy A71 comes with Android 10 and One UI 2. The phone also has Samsung Knox for added system security. Currently, it has been updated to Android 13 with One UI 5.0
On 18 August 2020, it was announced by Samsung that select Galaxy devices would be supported for three generations of Android software updates, of which the A71 was included.
On 2 December 2020, the Galaxy A71 was announced to be eligible for the Android 11 upgrade with One UI 3.
Owing to the A71 being listed for three generations of Android software updates, it's highly likely that the A71 will receive two more major Android upgrades after receiving Android 11.
History
The Samsung Galaxy A71 was announced and released in December of 2019 along with the Galaxy A51. Samsung later announced a 5G variant in April 2020 featuring an Exynos 980 SoC. A 5G ultra-wideband version with mmWave support is exclusive to Verizon.
See also
Samsung Galaxy A51
Samsung Galaxy A70
Samsung Galaxy A series
References
Samsung Galaxy
Phablets
Mobile phones introduced in 2019
Android (operating system) devices
Mobile phones with multiple rear cameras
Mobile phones with 4K video recording
Discontinued Samsung Galaxy smartphones | Samsung Galaxy A71 | [
"Technology"
] | 1,053 | [
"Crossover devices",
"Phablets"
] |
63,199,559 | https://en.wikipedia.org/wiki/Sony%20Xperia%201%20II | The Sony Xperia 1 II is an Android smartphone manufactured by Sony Mobile. Part of Sony's Xperia series, the phone was announced along with the mid-range Xperia 10 II on February 24, 2020. Key upgrades over its predecessor, the Xperia 1, include support for 5G connectivity and Qi wireless charging, and a triple-lens camera which incorporates ZEISS-branded lenses with T✻ (T-Star) anti-reflective coating as well as technology brought over from Sony's Alpha camera lineup.
The Xperia 1 II ships with support for 5G NR in Europe and Asia (making it Sony's first Xperia device to support this network), while the United States ships with a 4G variant. Although 5G networks are supported, it only supports "sub-6" 5G, meaning it is not compatible with millimeter-wave (mmWave) networks.
Design
The Xperia 1 II retains Sony's signature square design that is seen on previous Xperia phones. The phone has Corning Gorilla Glass 6 protection on the front and back as well as IP65 and IP68 certifications for water resistance. The build has a pair of symmetrical bezels on the top and the bottom, where the front-facing dual stereo speakers and the front camera are placed. The left side of the phone contains a compartment for a SIM card and a microSD card, while the right side contains a fingerprint reader embedded into the power button, a volume rocker and a shutter button. The rear cameras are arranged in a vertical strip. The phone shipped in five colors with the first three: Black, Purple and White available globally. There are also two colors exclusive to East Asian markets, Frosted Black for Japan and Mainland China and Mirror Lake Green for Mainland China and Taiwan.
Specifications
Hardware
The Xperia 1 II has a Qualcomm Snapdragon 865 SoC and an Adreno 650 GPU, accompanied by 8 GB or 12 GB of RAM, 256 GB storage space (which can be expanded up to 1 TB via the microSD card slot), and one nano SIM card slot. The display is identical to the one on the Xperia 1, a 6.5-inch 4K HDR OLED with a 21:9 aspect ratio, which Sony claims offers "unprecedented color accuracy". It is also capable of displaying one billion colors; most smartphone displays have sixteen million colors. The phone has a 4000 mAh battery, and supports wireless charging. The phone has front-facing dual stereo speakers and a 3.5 mm audio jack. The latter feature was not present on Sony's previous flagship phone, and technology journalists noted it as unusual in a flagship smartphones in 2020.
Camera
The phone has a triple 12 MP camera setup and a 3D iToF sensor on the back, and an 8 MP camera on the front. The rear cameras comprise the main lens (24 mm f/1.7), the ultra wide angle lens (16 mm f/2.2), and the telephoto lens (70 mm f/2.4); each uses ZEISS' T✻ (T-Star) anti-reflective coating. The phone has support for 4K video recording for up to 60 FPS and for 2K for up to 120 FPS. Android 11 update enables 4K video recording up to 120 FPS
Software
The Xperia 1 II released with Android 10, now updated to Android 12. Sony has also paired the phone's camera tech with a "Photo Pro" mode developed by Sony's camera division α (Alpha) and a "Cinema Pro" mode developed by Sony's cinematography division CineAlta, whose features take after Sony's Alpha and CineAlta cameras.
Notes
References
External links
Android (operating system) devices
Discontinued flagship smartphones
Sony smartphones
Mobile phones introduced in 2020
Mobile phones with multiple rear cameras
Mobile phones with 4K video recording | Sony Xperia 1 II | [
"Technology"
] | 799 | [
"Discontinued flagship smartphones",
"Flagship smartphones"
] |
63,199,597 | https://en.wikipedia.org/wiki/Institute%20of%20Nuclear%20Physics%20of%20the%20Polish%20Academy%20of%20Sciences | The (Henryka Niewodniczański) Institute of Nuclear Physics Polish Academy of Sciences is a research center in the field of nuclear physics of the Polish Academy of Sciences, located in Kraków. It was founded in 1955 by Henryk Niewodniczański. In 1988 the institute was named after Niewodniczański. The co-founder of the Institute was Marian Mięsowicz. The institute conducts research in four main areas:
Astrophysics and particle physics,
Nuclear physics and strong interactions,
Condensed matter (including nano-materials),
Interdisciplinary and applied research, which involves applications of physics in medicine, biology, dosimetry, environmental protection, nuclear geophysics, radiochemistry, high-temperature plasma diagnostics, the study of complex systems, such as the human brain, econophysics or linguistics.
See also
Cosmic-Ray Extremely Distributed Observatory
References
Physics organizations
Institutes of the Polish Academy of Sciences
1955 establishments in Poland
Organizations established in 1955
Nuclear physics | Institute of Nuclear Physics of the Polish Academy of Sciences | [
"Physics"
] | 198 | [
"Nuclear physics"
] |
63,200,483 | https://en.wikipedia.org/wiki/Wulf%20Bernard%20Kunkel | Wulf Bernard Kunkel (6 February 1923, Eichenau, Germany – 3 September 2013, Oakland, California) was a German-born American physicist, specializing in plasma physics, especially "the development of ion beams for plasma heating".
Kunkel attended the International Quaker School Eerde in Eerde, Ommen in the Netherlands. During the Second World War, he studied physics at the University of Amsterdam. After WW II ended, he studied physics at the University of California, Berkeley (UC Berkeley), where he graduated with bachelor's degree in 1948 and PhD in 1951. From 1951 to 1956 he worked at UC Berkeley's Institute of Engineering Research. In 1956 he joined the UC Radiation Laboratory (renamed in 1958 the Lawrence Berkeley National Laboratory, LBNL) and also became a lecturer in the physics department, UC Berkeley. There he was a full professor from 1967 to 1991, when he retired as professor emeritus. From 1971 to 1991 he served as leader of LBNL's fusion research program.
Kunkel was a Guggenheim Fellow for the two academic years 1955–1956 and 1972–1973. He was elected a Fellow of the American Physical Society in 1955. He received Germany's Alexander von Humboldt Award in 1982.
Upon his death he was survived by his widow, three children, and two grandchildren.
Selected publications
1979 (This paper "describes the use and future of high-power neutral-beam injectors to heat plasma."
References
1923 births
2013 deaths
University of California, Berkeley alumni
University of California, Berkeley College of Letters and Science faculty
Lawrence Berkeley National Laboratory people
Plasma physicists
20th-century American physicists
20th-century German physicists
Fellows of the American Physical Society
German emigrants to the United States | Wulf Bernard Kunkel | [
"Physics"
] | 350 | [
"Plasma physicists",
"Plasma physics"
] |
63,200,544 | https://en.wikipedia.org/wiki/Katie%20Bush | Katie Bush, known as 'America's Favorite Lady', is a Canadian-born American digital, net, and installation artist. Her work aims to re-evaluate the American Dream in a humorous and satirical way through her use of ready-made clip art. Her work has been exhibited in venues internationally as well as in print and online at Eleven Bulls, Rhizome.org and Scissorkick.com. It has also been featured in BoingBoing, The British Medical Journal, Dazed & Confused, and Art XX. She is San Francisco-based.
Early life and education
Katie Bush was born in Canada in 1972. In 1996, she received a BFA in Photography from the Nova Scotia College of Art and Design in Halifax, Canada and was influenced by the work of Garry Neil Kennedy. Inspired by Kathy Acker and Sharon Grace, she went on to receive an MFA in New Genres from the San Francisco Art Institute in 2000. Referred to as a "modern day digital sweetheart" and "visual terrorist with a heart of gold," Bush has been exhibiting her work internationally since 1993.
Subject matter
Bush has a variety of inspirations for her work including consumerism, the business of war, social (in)equality, and the ongoing cleanliness of chemically-treated suburban carpet areas. In an interview with Digital America, she mentions finding inspiring work, exhibitions, and conversations at CTheory and rhizome.org. Bush explains that she often still finds inspiration for new possibilities within her work from these sites and their archives.
Major works
"Destroy Evil"
"Destroy Evil" or "Destroyevil.com" is an on-going art website created as a critique of the 2002 'Axis of Evil' speech by George Bush. It was created the night after his speech and its official launch was July 4, 2002. Upon accessing the site, viewers see a calendar that has clickable squares and the message "Evil Has Yet To Come!". The viewer is able to interact with the site by clicking through it to discover an ongoing display of images showing bombs, babies, and medical procedures. Through this interaction, viewers can choose their (evil) adventure and can explore the site in a linear or nonlinear way. All of the animations on the site are white, black, red, and green following a good/evil, stop/go mentality. The scenes depicted through the images aim to question goals of money, power, sex, fame, and the pursuit of happiness and how it is presented in mass media. In her interview with Digital America, Bush explains that "Destroyevil.com is about polarizing patriotic forces and the combative suburban energies that show the most promise to (properly) loop in cyberspace forever". "Destroy Evil" is an ongoing project that Bush continues to add to every month until the entire calendar year is complete. With these additions, Bush includes images and aspects that touch on current sociopolitical events and positions. For example, she uses phrases spoken by Donald Trump and puts them in URLs that redirect to destroyevil.com.
"Rapture of the First Fruits"
"Rapture of the First Fruits" is "an illuminated panorainbow lady output dedicated to the morally-upright babies of a new tomorrow." In this work, Bush uses psychedelic configurations of pixels among layers of defective plutonium-tipped missiles, minivans, baby heads projectile vomiting American flags, etc to make a statement against the voter-approved ban on gay marriage at the time.
"All Systems Go!"
"All Systems Go!" was created in 2001. It is a web-art piece that creates discussion about virus, disease and media memes. Users can navigate through this artwork and discover a variety of small animated vignettes that showcase the banality of suburban existence. The various characters Bush includes in her work often share a helplessness and vulnerability, trapped in a continuous loop. Characters in "All Systems Go!" include a trapeze artist dropping his partner, a man in a sitz bath, a baby being ambushed by a red alligator, etc., repeating their mistakes unless they do something bad enough that stops them from doing so.
"Seeking to Destroy Families and Faith" (exhibition)
"Seeking to Destroy Families and Faith" was an exhibition presented in two parts. The digital prints that make up the exhibition were presented in two separate locations because they were so opposed in their homophobic vs. heterophobic nature. Part A consisted of large format (190 sq. ft.) anti-gay/anti-straight digital prints and was shown at Mojuju Tatu in San Francisco from June 19 to September 1, 2010. Part B was consisted of a minivan-centric anti-family installation that was shown at the ATA Right Window Gallery in San Francisco from July 4 to July 30, 2010. Bush's exhibition was extended through to October 15, 2010 at 2Spirit Tattoo as a 200 sq. ft. display of, as Bush stated, "kaleidoscopic socio-sexual marital mayhem."
"Neither Here/Nor There" (exhibition)
"Neither Here Nor There" was an exhibition presented at Glama-Rama in San Francisco from February 15 to April 10, 2004. In this show, Bush collected imagery from her online projects: www.destroyevil.com and www.lovekatie.com. She combined this imagery in such a way to showcase comparisons between an excess of shopping and bombing.
"You and What Army! Combative Digital Love Squirts by Katie Bush" (exhibition)
"You and What Army! Combative Digital Love Squirts by Katie Bush" was an exhibition inspired by out-of-state, church-backed funding of Prop 8 and the voter-approved ban on gay marriage. Included in this show was a large-scale triptych portraying, according to Bush, "an ominous Mormon church aiming nuclear missiles at screaming gay baby heads who projectile vomit color onto...lesbian cheerleaders."
Exhibitions
DestroyEvil.com July 4, 2002 (current)
Gold Standards in Dark Times. Spark Arts, San Francisco, Jun. 2017
Seeking to Destroy Families & Faith PART A, Mojuju Tatu, San Francisco, Jun-Sept. 2010
Seeking to Destroy Families & Faith PART B, ATA Right Window Gallery, Jul. 2010
www.lovekatie.com, 1996-2006
In a World with so many Things, Glama-Rama, San Francisco, Aug. 2005
Neither Here Nor There, Glama-Rama, San Francisco, Feb. 15-Apr. 10, 2004
Expected to Stimulate, The Lexington, San Francisco, Jun. 2003
All Systems Go!, Off-ramp Gallery, NY www.off-ramp.org, Oct. 2001
Tina and Carl Sell Katie, Fort Mason, San Francisco, 2000
The Scattering of Katie's Eggs, Easter Sunday, Downtown Toronto, Ontario, 1997
Kiss my Fence, Again, Anna Leonowen's, Halifax, Canada, 1996
Memefest 2005 (winner), Slovenija, Jun. 2005
Fylkingen HZNet, Sweden, #5, Jun. 2005
Stunned, Net Art Open, Ireland, Jun. 2005
chico.art.net, the electric arts program, CSU, California, Dec. 2004
Electrofringe 2004, Newcastle/This is not Art Festival, Australia, Sept.-Oct. 2004
6th International Digital Art Exhibition and Colloquium, Centro Cultural, Havana, Cuba, Jun. 2004
MAF-04, Thailand New Media Art Festival, Bangkok, Mar. 2004
Hilchot Shchenim-Lows for Neighbors, The Israeli Center for Digital Art, Israel, 2004
FILE, Electronic Language and International Festival, Brazil, 2003
SARS Digital Art Exhibit, The SARS PROJECT, 2003
Peam 2003, Pescara Electronic Artist Meeting, Pescara, Italy, 2003
Istanbul Museum Web Biennial, Istanbul, Turkey, 2003
I-Highway - Netart from Canada, Java Museum, Germany, Jun. 2003
The Timmy Show, Glama-Rama, San Francisco, 2003
The Wartime Project, 2003, London, Italy, Mexico, U.S.A., Spain, Amsterdam
Visual Art @ athica.org, A Collection of New Media Artwork, Athens, Georgia, 2003
NET.FILM, 3rd Biennial Exhibition, ABC No Rio Gallery, NY, 2002
Don't Ever Change, Tuttle Gallery, Baltimore, MD, 2001
Suburban Samizdat, Buffalo, NY, Sept., Oct., Dec. 2001-2003
Wallpapers, Art Gallery of Nova Scotia, Nova Scotia, Canada, 2000
Graduate MFA Exhibition, Fort Mason, San Francisco, CA, 2000
Continuing MFA Exhibition, Diego Rivera, San Francisco, CA, 1999
Intimations, Angell Gallery, Toronto, Ontario, 1999
Apaware: Cash and Carry, Linz, Austria, 1999
Art Metropole Auction & Benefit, Christopher Cutts Gallery, Toronto, Ontario, 1997
www.pfplayground.com, (online/archived), 1997
Graduating BFA Exhibition, N.S.C.A.D., Nova Scotia, 1996
Color, Khyber Art Center, Halifax, Nova Scotia, 1995
Drawings, Anna Leonowen's Gallery, Halifax, Canada, 1994
Publications
Katie Gets Wet, Art Metropole, Toronto, Ontario, 1998
Destroy UFO'S!, Halifax, Vancouver, Toronto, Canada, 1993-1997
Bathhouse Magazine, vol. 1, no. 2, 2002
References
Living people
American digital artists
Canadian digital artists
American women installation artists
American installation artists
Canadian installation artists
Artists from San Francisco
1972 births
San Francisco Art Institute alumni
Net.artists
NSCAD University alumni
21st-century American women
Canadian emigrants to the United States | Katie Bush | [
"Technology"
] | 1,997 | [
"Multimedia",
"Net.artists"
] |
59,600,531 | https://en.wikipedia.org/wiki/Phase%20reduction | Phase reduction is a method used to reduce a multi-dimensional dynamical equation describing a nonlinear limit cycle oscillator into a one-dimensional phase equation. Many phenomena in our world such as chemical reactions, electric circuits, mechanical vibrations, cardiac cells, and spiking neurons are examples of rhythmic phenomena, and can be considered as nonlinear limit cycle oscillators.
History
The theory of phase reduction method was first introduced in the 1950s, the existence of periodic solutions to nonlinear oscillators under perturbation, has been discussed by Malkin in, in the 1960s, Winfree illustrated the importance of the notion of phase and formulated the phase model for a population of nonlinear oscillators in his studies on biological synchronization. Since then, many researchers have discovered different rhythmic phenomena related to phase reduction theory.
Phase model of reduction
Consider the dynamical system of the form
where is the oscillator state variable, is the baseline vector field. Let be the flow induced by the system, that is, is the solution of the system for the initial condition . This system of differential equations can describe for a neuron model for conductance with , where represents the voltage difference across the membrane and represents the -dimensional vector that defines gating variables. When a neuron is perturbed by a stimulus current, the dynamics of the perturbed system will no longer be the same with the dynamics of the baseline neural oscillator.
The target here is to reduce the system by defining a phase for each point in some neighbourhood of the limit cycle. The allowance of sufficiently small perturbations (e.g. external forcing or stimulus effect to the system) might cause a large deviation of the phase, but the amplitude is perturbed slightly because of the attracting of the limit cycle. Hence we need to extend the definition of the phase to points in the neighborhood of the cycle by introducing the definition of asymptotic phase (or latent phase). This helps us to assign a phase to each point in the basin of attraction of a periodic orbit. The set of points in the basin of attraction of that share the same asymptotic phase is called the isochron (e.g. see Figure 1), which were first introduced by Winfree. Isochrons can be shown to exist for such a stable hyperbolic limit cycle . So for all point in some neighbourhood of the cycle, the evolution of the phase can be given by the relation , where is the natural frequency of the oscillation. By the chain rule we then obtain an equation that govern the evolution of the phase of the neuron model is given by the phase model:
where is the gradient of the phase function with respect to the vector of the neuron's state vector , for the derivation of this result, see This means that the -dimensional system describing the oscillating neuron dynamics is then reduced to a simple one-dimensional phase equation. One can notice that, it is impossible to retrieve the full information of the oscillator from the phase because
is not one-to-one mapping.
Phase model with external forcing
Consider now a weakly perturbed system of the form
where is the baseline vector field, is a weak periodic external forcing (or stimulus effect) of period , which can be different from (in general), and frequency , which might depend on the oscillator state . Assuming that the baseline neural oscillator (that is, when ) has an exponentially stable limit cycle with period (example, see Figure 1) that is normally hyperbolic, it can be shown that persists under small perturbations. This implies that for a small perturbation, the perturbed system will remain close to the limit cycle. Hence we assume that such a limit cycle always exists for each neuron.
The evolution of the perturbed system in terms of the isochrons is
where is the gradient of the phase with respect to the vector of the neuron's state vector , and is the stimulus effect driving the firing of the neuron as a function of time . This phase equation is a partial differential equation (PDE).
For a sufficiently small , a reduced phase model evaluated on the limit cycle of the unperturbed system can be given by, up to the first order of ,
where function measures the normalized phase shift due to a small perturbation delivered at any point on the limit cycle , and is called the phase sensitivity function or infinitesimal phase response curve.
In order to analyze the reduced phase equation corresponding to the perturbed nonlinear system, we need to solve a PDE, which is not a trivial one. So we need to simplify it into an autonomous phase equation for , which can more easily be analyzed. Assuming that the frequencies and are sufficiently small so that
, where is , we can introduce a new phase function .
By the method of averaging, assuming that does not vary within , we obtain an approximated phase equation
where , and is a -periodic function representing the effect of the periodic external forcing on the oscillator phase, defined by
The graph of this function can be shown to exhibit the dynamics of the approximated phase model, for more illustrations see.
Examples of phase reduction
For a sufficiently small perturbation of a certain nonlinear oscillator or a network of coupled oscillators, we can compute the corresponding phase sensitivity function or infinitesimal PRC .
References
Dynamical systems | Phase reduction | [
"Physics",
"Mathematics"
] | 1,117 | [
"Mechanics",
"Dynamical systems"
] |
59,600,751 | https://en.wikipedia.org/wiki/IR%20welding | IR welding is a welding technique that uses a non-contact heating method to melt and fuse thermoplastic parts together using the energy from infrared radiation. The process was first developed in the late 1900s, but due to the high capital cost of IR equipment the process was not commonly applied in industry until prices dropped in the 1990s. IR welding typically uses a range of wavelengths from 800 to 11,000 nm on the electromagnetic spectrum to heat, melt, and fuse the interface between two plastic parts through the absorption and conversion of the IR energy into heat. Laser welding is a similar joining process that applies IR radiation at a single wavelength.
There are many different welding techniques that use IR heating, with the three major modes being surface heating, through transmission IR welding (TTIr), and IR staking. A variety of heating configurations have been applied to these techniques such as scanning, continuous illumination, and mask welding. Advantages such as faster and controllable non-contact heating applicable for a wide range of simple or complex part geometries sets IR welding apart from other forms of plastic welding. CO detectors, IV bags, and brake transmission lines are just a few of the many products that utilize IR welds.
History
IR welding is categorized as a form thermal plastic welding alongside hot gas welding, hot tool welding, and extrusion welding. Although infrared radiation was first discovered in the 1800s, IR was not applied as a source of heat until the beginning of WWII when it was found to be more effective than the fuel convection ovens of that time. IR radiation was first tested for the welding of thermoplastic polymers in the late 1900s, but the process was relatively new and not fully understood. IR welding systems offered faster heating times than the other forms of thermal welding, but the high capital costs limited its development. With a decrease in the price of equipment in the 1990s, IR welding has become more popular in the industry.
Physics of IR welding
IR welding typically uses wavelengths from 800 to 11,000 nm on the electromagnetic spectrum. Plastics interact with IR radiation through reflection, transmission, and absorption. Incident IR radiation can either be reflected off the surface of the plastic, transmitted through the plastic, or absorbed into the plastic as other forms of energy including thermal energy. The ratio of these three interactions depends on the wavelength of the IR radiation and the receiving plastic's properties. Amorphous plastics are generally optically clear and can transmit almost all incident IR radiation. For this reason they are commonly used in TTIr. Semi-crystalline plastics can diffuse incident IR radiation between the amorphous and crystalline boundaries, reducing the transmittance and increasing the absorbance of the material. The higher absorptivity results in more heat generation for a given IR source. Additives such as clarifying agents can be used increase a plastic's transmittance while dies and pigments can be used increase the absorbance of a material. Increasing amounts of these additives can decrease the strength of both the material and the welded joint.
The closer the IR radiation source, the higher incidence efficiency on the material. IR radiation is most effective when directing radiation normal to the part. Radiation energy always affects the surface of a part while the depth of penetration that the energy can reach is dependent on the plastic's crystallinity.
Equipment
IR Sources
Potential IR welding sources include quartz lamps and ceramic heaters which can generate a wide range of IR wavelengths. Laser welding employs IR sources that operate at a single wavelength such as CO2 lasers, Nd:YAG lasers, laser diodes. The equipment selected for each welding process stems from the type of radiation produced. Quartz lamps produce wavelengths of around 1,000 to 5,000 nm and ceramic heaters produce wavelengths of around 5,000 to 10,000 nm.
Attachments
P-wave technology utilizes an IR lamp and a pre-placed focusing device such as an IR transducer or film that can filter and focus IR radiation at a desired wavelength and increased intensity within a selected area to improve weld penetration with minimal surface damage. This method allows improved IR welding of polymers with higher melting temperatures such as most fluoropolymers and polyketones.
IR welding techniques
The three major welding techniques used in the industry today include surface heating, through transmission IR welding, and IR staking. All IR welding techniques contain the following six basic steps in some form:
Loading of parts into the welding system that will hold the parts in place
Insertion of IR source in front of the face of each part that will welded together
Application of IR radiation to melt a thin layer of plastic on the surface of each part
Change-over in which the IR source is removed from the face of each part
Clamping of the parts to join the melted surfaces together under pressure as they cool and solidify
Unloading of the parts after the weld has been made
Surface Heating
Surface heating includes heating and melting of the interface between plastic parts with IR radiation and forcing the parts together into a molten joint that solidifies as one part. This process can be split into 3 phases as shown in the figure to the right: A) Loading of parts, insertion of the IR source, and IR application. B) Change-over with the removal of IR source and clamping of the parts to join them. C) Unloading of the parts after the weld was made.
Through Transmission IR Welding (TTIr)
TTIr welding is the joining of an IR transparent part to a second part such that the IR radiation travels through the transparent part and heat the surface of the second part as shown in the figure to the right. IR wavelengths are generally within 800 to 1050 nm. To make a transparent part absorbent to IR radiation, the addition of dies or colorants such as carbon black can be used. Highly absorbent thermoplastic films can be placed at the joint to receive the IR radiation and melt the interface during welding. Using these methods, TTIr welds can be completed between parts of both the same or different materials.
IR Staking
IR staking includes the localized welding of a thermoplastic stud or stake from one part into the cavity of a non-weldable part to form a mechanical fastener. As shown in the figure to the right, the polymer part and non-weldable part are first placed together (A), then the projecting polymer is melted and formed around the non-weldable part to fasten the two together (B). The stud can be heated through directed TTIr when pre-placed within the cavity of an IR transparent part, then melted to deform it into a button shape required to fill the cavity before solidifying. Surface IR radiation can also be used to soften a plastic stud which is then pressed into a button-shaped die to form a head before cooling and solidifying.
Heating Configurations
IR systems generally rely on one of three surface heating methods: scanning, continuous illumination, and mask welding.
Scanning
Scanning involves the movement of an IR beam across the surface of a part using either an automated motion system or galvanic mirrors. Equipment is limited by the speed of movements across the part's surface to maintain uniform temperatures on the surface. In TTIr welding, scanning allows the un-melted portion of the part to act as a mechanical stop in order to maintain the joint gap between the two parts.
Continuous illumination
Continuous illumination uses more than one IR radiation source to heat the entire joint interface at the same time. Part tolerances or fit is not as crucial with this method as the entire surface will be melted before welding. This method is useful when welding parts with complex geometries, employing the multiple IR sources to evenly heat all forms of joint interfaces.
Mask welding
Similar to continuous illumination, mask welding utilizes multiple IR sources to completely illuminate a joint interface while placing an IR radiation mask over the parts to control which regions will form a melt layer.
Materials
Below is a list of materials well known for their IR weldability:
Polycarbonate (PC)
Poly(methyl methacrylate) (PMMA)
Ethylene vinyl alcohol (EVOH)
Acrylic
Polystyrene (PS)
Acrylonitrile butadiene stryrene (ABS)
Polyvinyl chloride (PVC)
Polyethylene (PE)
Polypropylene (PP)
Polyketone (PK)
Elastomers
Polyamide (PA)
Polyoxymethylene (POM or Acetal)
Polytetrafluoroethylene (PTFE)
High density polyethylene (HDPE)
Glass fiber reinforced polyethylene (PPE)
Polybutylene terephthalate (PBT)
Glass fiber reinforced polyether sulfone (PES)
Advantages / Disadvantages
Advantages
Fast heating and cycle time than other thermal plastic welding processes
Non-contact heating on the weld interface prevents plastic parts from sticking to the heat source, as seen in hot plate welding
Controlled heat affected zone for reduced flash than seen in hot plate welding
Minimal contamination risk with prevention of production of particulate than other thermal plastic welding processes
Continuous and easily automated process
Potential for higher joint strengths and lower residual stresses than other thermal plastic welding processes
Cost-effective in comparison to laser welding
Direct heat transfer to parts allows for maximum energy efficiency and fast response time with lower weight equipment than other thermal plastic welding processes
Well suited for welding high temperature thermoplastics in comparison to hot plate welding
Disadvantages
IR welding parts and systems are more expensive than other thermal plastic welding processes
IR welding can only weld materials susceptible to IR waves and part interfaces exposed to IR radiation
Prolonged heating may cause material degradation or vapor oxidation entrapment
Applications
New joining technologies using IR welding are critical for fabricating complex parts and assemblies at high speeds and low costs. Although IR plastic welding has many advantages over other types of plastic welding, limitations such as equipment costs and susceptible materials properties reduce the amount of industrial applications of the method. A few examples of current industrial applications are shown below:
CO detector filters are IR welded to their plastic housing to prevent damaging the filter with particulate
Medical IV-bags are IR welded to achieve minimal flash and particulate generation for smooth and clean fluid flow
High-speed cut and seal film (300 m/min) processes allow for minimal fraying at the edges and cauterized seams
Brake fluid reservoirs are IR welded to prevent clogging and contamination of the small fluid transmission channels
PE pipes in the infrastructure of natural gas transmission undergo IR welding using TTIr to improve joint strength with minimal coupling deformation
References
Welding | IR welding | [
"Engineering"
] | 2,141 | [
"Welding",
"Mechanical engineering"
] |
59,601,438 | https://en.wikipedia.org/wiki/Inner%20core%20super-rotation | Inner core super-rotation is the eastward rotation of the inner core of Earth relative to its mantle, for a net rotation rate that is usually faster than Earth as a whole. A 1995 model of Earth's dynamo predicted super-rotations of up to 3 degrees per year; the following year, this prediction was supported by observed discrepancies in the time that p-waves take to travel through the inner and outer core.
A 1995 model of Earth's dynamo predicted super-rotations of up to 3 degrees per year; the following year, this prediction was supported by observed discrepancies in the time that p-waves take to travel through the inner and outer core. Utilizing both s and p waves dramatically increases the confidence levels of the many seismic data conclusions.
Seismic observations have made use of a direction dependence (anisotropy) of the speed of seismic waves in the inner core, as well as spatial variations in the speed. Other estimates come from free oscillations of Earth. The results are inconsistent and the existence of a super-rotation is still controversial, but it is probably less than 0.1 degrees per year.
When geodynamo models take into account gravitational coupling between the inner core and mantle, it lowers the predicted super-rotation to as little as 1 degree per million years. For the inner core to rotate despite gravitational coupling, it must be able to change shape, which places constraints on its viscosity.
A 2023 study reported that the spin of the Earth's inner core has stopped spinning faster than the planet's surface around 2009 and likely is now rotating slower than it.
Background
At the center of Earth is the core, a ball with a mean radius of 3480 kilometres that is composed mostly of iron. The outer core is liquid while the inner core, with a radius of 1220 km, is solid. Because the outer core has a low viscosity, it could be rotating at a different rate from the mantle and crust. This possibility was first proposed in 1975 to explain a phenomenon of Earth's magnetic field called westward drift: some parts of the field rotate about 0.2 degrees per year westward relative to Earth's surface. In 1981, David Gubbins of Leeds University predicted that a differential rotation of the inner and outer core could generate a large toroidal magnetic field near the shared boundary, accelerating the inner core to the rate of westward drift. This would be in opposition to the Earth's rotation, which is eastwards, so the overall rotation would be slower.
In 1995, Gary Glatzmeier at Los Alamos and Paul Roberts at UCLA published the first "self-consistent" three-dimensional model of the dynamo in the core. The model predicted that the inner core rotates 3 degrees per year faster than the mantle, a phenomenon that became known as super-rotation. 1996, Xiaodong Song and Paul G. Richards, scientists at the Lamont–Doherty Earth Observatory, presented seismic evidence for a super-rotation of 0.4 to 1.8 degrees per year, while another study estimated the super-rotation to be 3 degrees per year.
Seismic observations
The main observational constraints on inner core rotation come from seismology. When an earthquake occurs, two kinds of seismic wave travel down through the Earth: those with ground motion in the direction the wave propagates (p-waves) and those with transverse motion (s-waves). S-waves do not travel through the outer core because they involve shear stress, a type of deformation that cannot occur in a liquid. In seismic notation, a p-wave is represented by the letter P when traveling through the crust and mantle and by the letter K when traveling through the outer core. A wave that travels through the mantle, core and mantle again before reaching the surface is represented by PKP. For geometric reasons, two branches of PKP are distinguished: PKP(AB) through the upper part of the outer core, and PKP(BC) through the lower part. A wave passing through the inner core is referred to as PKP(DF). (Alternate names for these phases are PKP1, PKP2 and PKIKP.) Seismic waves can travel multiple paths from an earthquake to a given sensor.
PKP(BC) and PKP(DF) waves have similar paths in the mantle, so any difference in the overall travel time is mainly due to the difference in wave speeds between the outer and inner core. Song and Richards looked at how this difference changed over time. Waves traveling from south to north (emitted by earthquakes in the South Sandwich Islands and received at Fairbanks, Alaska) had a differential that changed by 0.4 seconds between 1967 and 1995. By contrast, waves traveling near the equatorial plane (e.g., between Tonga and Germany) showed no change.
One of the criticisms of the early estimates of super-rotation was that uncertainties about the hypocenters of the earthquakes, particularly those in the earlier records, caused errors in the measurement of travel times. This error can be reduced by using data for doublet earthquakes. These are earthquakes that have very similar waveforms, indicating that the earthquakes were very close to each other (within about a kilometer). Using doublet data from the South Sandwich Islands, a study in 2015 arrived at a new estimate of 0.41° per year.
Seismic observations – in particular "temporal changes between repeated seismic waves that should traverse the same path through the inner core" – were used to reveal a core rotation slow-down around 2009. This is not thought to have major effects and one cycle of the oscillation in rotation is thought to be about seven decades, coinciding with several other geophysical periodicities, "especially the length of day and magnetic field".
Inner core anisotropy
Song and Richards explained their observations in terms of the prevailing model of inner core anisotropy at the time. Waves were observed to travel faster between north and south than along the equatorial plane. A model for the inner core with uniform anisotropy had a direction of fastest travel tilted at an angle 10° from the spin axis of the Earth. Since then, the model for the anisotropy has become more complex. The top 100 kilometers are isotropic. Below that, there is stronger anisotropy in a "western" hemisphere (roughly centered on the Americas) than in an "eastern" hemisphere (the other half of the globe), and the anisotropy may increase with depth. There may also be a different orientation of anisotropy in an "innermost inner core" (IMIC) with a radius of about 550 kilometers.
A group at the University of Cambridge used travel time differentials to estimate the longitudes of the hemisphere boundaries with depth up to 90 kilometers below the inner core boundary. Combining this information with an estimate for the rate of growth for the inner core, they obtained a rate of 0.1–1° per million years.
Estimates of the rotation rate based on travel time differentials have been inconsistent. Those based on the Sandwich Island earthquakes have the fastest rates, although they also have a weaker signal, with PKP(DF) barely emerging above the noise. Estimates based on other paths have been lower or even in the opposite direction. By one analysis, the rotation rate is constrained to be less than 0.1° per year.
Heterogeneity
A study in 1997 revisited the Sandwich Islands data and came to a different conclusion about the origin of changes in travel times, attributing them to local heterogeneities in wave speeds. The new estimate for super-rotation was reduced to 0.2–0.3° per year.
Inner core rotation has also been estimated using PKiKP waves, which scatter off the surface of the inner core, rather than PKP(DF) waves. Estimates using this method have ranged from 0.05 to 0.15° per year.
Normal modes
Another way of constraining the inner core rotation is using normal modes (standing waves in Earth), giving a global picture. Heterogeneities in the core split the modes, and changes in the "splitting functions" over time can be used to estimate the rotation rate. However, their accuracy is limited by the shortage of seismic stations in the 1970s and 1980s, and the inferred rotation can be positive or negative depending on the mode. Overall, normal modes are unable to distinguish the rotation rate from zero.
Theory
In the 1995 model of Glatzmeier and Roberts, the inner core is rotated by a mechanism similar to an induction motor. A thermal wind in the outer core gives rise to a circulation pattern with flow from east to west near the inner core boundary. Magnetic fields passing through the inner and outer cores provide a magnetic torque, while viscous torque on the boundary keeps the inner core and the fluid near it rotating at the same rate on average.
The 1995 model did not include the effect of gravitational coupling between density variations in the mantle and topography on the inner core boundary. A 1996 study predicted that it would force the inner core and mantle to rotate at the same rate, but a 1997 paper showed that relative rotation could occur if the inner core was able to change its shape. This would require the viscosity to be less than 1.5 x 1020 pascal-seconds (Pa·s). It also predicted that, if the viscosity were too low (less than 3 x 1016 Pa·s), the inner core would not be able to maintain its seismic anisotropy. However, the source of the anisotropy is still not well understood. A model of the viscosity of the inner core based on Earth's nutations constrains the viscosity to 2–7 × 1014 Pa·s.
Geodynamo models that take into account gravitational locking and changes in the length of day predict a super-rotation rate of only 1° per million years. Some of the inconsistencies between measurements of the rotation may be accommodated if the rotation rate oscillates.
See also
Inverse problem
Notes and references
Further reading
Rotation
Structure of the Earth
Geodynamics
1996 in science | Inner core super-rotation | [
"Physics"
] | 2,104 | [
"Physical phenomena",
"Motion (physics)",
"Classical mechanics",
"Rotation"
] |
59,601,600 | https://en.wikipedia.org/wiki/Squeeze%20flow | Squeeze flow (also called squeezing flow, squeezing film flow, or squeeze flow theory) is a type of flow in which a material is pressed out or deformed between two parallel plates or objects. First explored in 1874 by Josef Stefan, squeeze flow describes the outward movement of a droplet of material, its area of contact with the plate surfaces, and the effects of internal and external factors such as temperature, viscoelasticity, and heterogeneity of the material. Several squeeze flow models exist to describe Newtonian and non-Newtonian fluids undergoing squeeze flow under various geometries and conditions. Numerous applications across scientific and engineering disciplines including rheometry, welding engineering, and materials science provide examples of squeeze flow in practical use.
Basic Assumptions
Conservation of mass (expressed as a continuity equation), the Navier-Stokes equations for conservation of momentum, and the Reynolds number provide the foundations for calculating and modeling squeeze flow. Boundary conditions for such calculations include assumptions of an incompressible fluid, a two-dimensional system, neglecting of body forces, and neglecting of inertial forces.
Relating applied force to material thickness:
Where is the applied squeezing force, is the initial length of the droplet, is the fluid viscosity, is the width of the assumed rectangular plate, is the final height of the droplet, and is the change in droplet height over time. To simplify most calculations, the applied force is assumed to be constant.
Newtonian fluids
Several equations accurately model Newtonian droplet sizes under different initial conditions.
Consideration of a single asperity, or surface protrusion, allows for measurement of a very specific cross-section of a droplet. To measure macroscopic squeeze flow effects, models exist for two the most common surfaces: circular and rectangular plate squeeze flows.
Single asperity
For single asperity squeeze flow:
Where is the initial height of the droplet, is the final height of the droplet, is the applied squeezing force, is the squeezing time, is the fluid viscosity, is the width of the assumed rectangular plate, and is the initial length of the droplet.
Based on conservation of mass calculations, the droplet width is inversely proportional to droplet height; as the width increases, the height decreases in response to squeezing forces.
Circular plate
For circular plate squeeze flow:
is the radius of the circular plate.
Rectangular plate
For rectangular plate squeeze flow:
These calculations assume a melt layer that has a length much larger than the sample width and thickness.
Non-Newtonian fluids
Simplifying calculations for Newtonian fluids allows for basic analysis of squeeze flow, but many polymers can exhibit properties of non-Newtonian fluids, such as viscoelastic characteristics, under deformation. The power law fluid model is sufficient to describe behaviors above the melting temperature for semicrystalline thermoplastics or the glass transition temperature for amorphous thermoplastics, and the Bingham fluid model provides calculations based on variations in yield stress calculations.
Power law fluid
For squeeze flow in a power law fluid:
Where (or ) is the flow consistency index and is the dimensionless flow behavior index.
Where is the flow consistency index, is the initial flow consistency index, is the activation energy, is the universal gas constant, and is the absolute temperature.
During experimentation to determine the accuracy of the power law fluid model, observations showed that modeling slow squeeze flow generated inaccurate power law constants ( and ) using a standard viscometer, and fast squeeze flow demonstrated that polymers may exhibit better lubrication than current constitutive models will predict. The current empirical model for power law fluids is relatively accurate for modeling inelastic flows, but certain kinematic flow assumptions and incomplete understanding of polymeric lubrication properties tend to provide inaccurate modeling of power law fluids.
Bingham fluid
Bingham fluids exhibit uncommon characteristics during squeeze flow. While undergoing compression, Bingham fluids should fail to move and act as a solid until achieving a yield stress; however, as the parallel plates move closer together, the fluid shows some radial movement. One study proposes a “biviscosity” model where the Bingham fluid retains some unyielded regions that maintain solid-like properties, while other regions yield and allow for some compression and outward movement.
Where is the known viscosity of the Bingham fluid, is the "paradoxical" viscosity of the solid-like state, and is the biviscosity region stress. To determine this new stress:
Where is the yield stress and is the dimensionless viscosity ratio. If , the fluid exhibits Newtonian behavior; as , the Bingham model applies.
Applications
Squeeze flow application is prevalent in several science and engineering fields. Modeling and experimentation assist with understanding the complexities of squeeze flow during processes such as rheological testing, hot plate welding, and composite material joining.
Rheological testing
Squeeze flow rheometry allows for evaluation of polymers under wide ranges of temperatures, shear rates, and flow indexes. Parallel plate plastometers provide analysis for high viscosity materials such as rubber and glass, cure times for epoxy resins, and fiber-filled suspension flows. While viscometers provide useful results for squeeze flow measurements, testing conditions such as applied rotation rates, material composition, and fluid flow behaviors under shear may require the use of rheometers or other novel setups to obtain accurate data.
Hot plate welding
During conventional hot plate welding, a successful joining phase depends on proper maintenance of squeeze flow to ensure that pressure and temperature create an ideal weld. Excessive pressure causes squeeze out of valuable material and weakens the bond due to fiber realignment in the melt layer, while failure to allow cooling to room temperature creates weak, brittle welds that crack or break completely during use.
Composite material joining
Prevalent in the aerospace and automotive industries, composites serve as expensive, yet mechanically strong, materials in the construction of several types of aircraft and vehicles. While aircraft parts are typically composed of thermosetting polymers, thermoplastics may become an analog to permit increased manufacturing of these stronger materials through their melting abilities and relatively inexpensive raw materials. Characterization and testing of thermoplastic composites experiencing squeeze flow allow for study of fiber orientations within the melt and final products to determine weld strength. Fiber strand length and size show significant effects on material strength, and squeeze flow causes fibers to orient along the load direction while being perpendicular to the joining direction to achieve the same final properties as thermosetting composites.
References
Welding
Plastics
Materials science
Molding processes | Squeeze flow | [
"Physics",
"Materials_science",
"Engineering"
] | 1,338 | [
"Applied and interdisciplinary physics",
"Welding",
"Unsolved problems in physics",
"Materials science",
"nan",
"Mechanical engineering",
"Amorphous solids",
"Plastics"
] |
59,602,196 | https://en.wikipedia.org/wiki/Digital%20media%20use%20and%20mental%20health | The relationships between digital media use and mental health have been investigated by various researchers—predominantly psychologists, sociologists, anthropologists, and medical experts—especially since the mid-1990s, after the growth of the World Wide Web and rise of text messaging. A significant body of research has explored "overuse" phenomena, commonly known as "digital addictions", or "digital dependencies". These phenomena manifest differently in many societies and cultures. Some experts have investigated the benefits of moderate digital media use in various domains, including mental health, and treating mental health problems with novel technological solutions. Studies have also suggested that certain digital media use, such as online support communities, may offer mental health benefits, although the effects are quite complex.
The delineation between beneficial and pathological use of digital media has not been established. There are no widely accepted diagnostic criteria, although some experts consider overuse a manifestation of underlying psychiatric disorders. The prevention and treatment of pathological digital media use is also not standardized, although guidelines for safer media use for children and families have been developed. The 2013 fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the International Classification of Diseases (ICD-11) do not include diagnoses for problematic internet use and problematic social media use; the ICD-11 includes a diagnosis for gaming disorder (commonly known as video game addiction), whereas the DSM-5 does not. Debate over how and when to diagnose these conditions is ongoing as of 2023. The use of the term addiction to refer to these phenomena and diagnoses has been questioned.
Digital media and screen time amongst modern social media apps such as Instagram, TikTok, Snapchat and Facebook have changed how children think, interact and develop in positive and negative ways, but researchers are unsure about the existence of hypothesized causal links between digital media use and mental health outcomes. Those links appear to depend on the individual and the platforms they use. Several large technology firms have made commitments or announced strategies to try to reduce the risks of digital media use.
History and terminology
The relationship between digital technology and mental health has been investigated from many perspectives. Benefits of digital media use in childhood and adolescent development have been found. Concerns have been expressed by researchers, clinicians and the public in regard to apparent compulsive behaviors of digital media users, as correlations between technology overuse and mental health problems become apparent.
Terminologies used to refer to compulsive digital-media-use behaviours are not standardized or universally recognised. They include "digital addiction", "digital dependence", "problematic use", or "overuse", often delineated by the digital media platform used or under study (such as problematic smartphone use or problematic internet use). Unrestrained use of technological devices may affect developmental, social, mental and physical well-being and may result in symptoms akin to other psychological dependence syndromes, or behavioral addictions. The focus on problematic technology use in research, particularly in relation to the behavioural addiction paradigm, is becoming more accepted, despite poor standardization and conflicting research.
Internet addiction has been proposed as a diagnosis since the 1998 and social media and its relation to addiction has been examined since 2009. A 2018 Organisation for Economic Co-operation and Development (OECD) report stated there were benefits of structured and limited internet use in children and adolescents for developmental and educational purposes, but that excessive use can have a negative impact on mental well-being. It also noted an overall 40% increase in internet use in school-age children between 2010 and 2015, and that different OECD nations had marked variations in rates of childhood technology use, as well as differences in the platforms used. Hence, why it is so important for adolescents' to be trained to use social media, as it will ensure that users have developed psychologically informed competencies and skills that will maximize the chances for balanced, safe, and meaningful social media use.
The Diagnostic and Statistical Manual of Mental Disorders has not formally codified problematic digital media use in diagnostic categories, but it deemed internet gaming disorder to be a condition for further study in 2013. Gaming disorder, commonly known as video game addiction, has been recognised in the ICD-11. Different recommendations in the DSM and the ICD are due partly to the lack of expert consensus, the differences in emphasis in the classification manuals, as well as difficulties using animal models for behavioural addictions.
The utility of the term addiction in relation to the overuse of digital media has been questioned, in regard to its suitability to describe new, digitally mediated psychiatric categories, as opposed to overuse being a manifestation of other psychiatric disorders. Usage of the term has also been criticised for drawing parallels with substance use behaviours. Careless use of the term may cause more problems—both downplaying the risks of harm in seriously affected people, as well as overstating risks of excessive, non-pathological use of digital media. The evolution of terminology relating excessive digital media use to problematic use rather than addiction was encouraged by Panova and Carbonell, psychologists at Ramon Llull University, in a 2018 review.
Due to the lack of recognition and consensus on the concepts used, diagnoses and treatments are difficult to standardize or develop. Heightened levels of public anxiety around new media (including social media, smartphones and video games) further obfuscate population-based assessments, as well as posing management dilemmas. Radesky and Christakis, the 2019 editors of JAMA Paediatrics, published a review that investigated "concerns about health and developmental/behavioral risks of excessive media use for child cognitive, language, literacy, and social-emotional development." Due to the ready availability of multiple technologies to children worldwide, the problem is bi-directional, as taking away digital devices may have a detrimental effect, in areas such as learning, family relationship dynamics, and overall development.
Problematic use
Though associations have been observed between digital media use and mental health symptoms or diagnoses, causality has not been established; nuances and caveats published by researchers are often misunderstood by the general public, or misrepresented by the media. Females are likelier to overuse social media and males video games. Following from this, problematic digital media use may not be singular constructs, may be delineated based on the digital platform used, or reappraised in terms of specific activities (rather than addiction to the digital medium). Problematic social media use can also result in fear of missing out (FoMO) in which symptoms of anxiety and psychological stress exasperated with the fear of potentially missing content present online leaving the individual feeling unfulfilled or left out of the loop. Research also suggests that FoMo can worsen mental health issues, such as anxiety and depression, especially among younger digital users since they are prone to comparison.
When an individual has FoMo they will be more likely to constantly check their social media accounts using their personal devices to check social media or messages to ensure they are up to date with information that is occurring within the individual's social network. This constant need to check social media platforms for information induces feelings of anxiety driving individuals to get involved with problematic social media use.
Access to means of communication
In 1999, 58% of Finnish citizens had a mobile phone, including 75% of 15-17 year olds. In 2000, a majority of U.S. households had at least one personal computer and internet access the following year. In 2002, a majority of U.S. survey respondents reported having a mobile phone. In September and December 2006 respectively, Luxembourg and the Netherlands became the first countries to completely transition from analog to digital television, while the United States commenced its transition in 2008. In September 2007, a majority of U.S. survey respondents reported having broadband internet at home. In January 2013, a majority of U.S. survey respondents reported owning a smartphone. An estimated 40% of U.S. households in 2006 owned a dedicated home video game console, and by 2015, 51 percent of U.S. households owned a dedicated home video game console. In April 2015, one survey of U.S. teenagers ages 13 to 17 reported that nearly three-quarters of them either owned or had access to a smartphone, and 92 percent went online daily, with 24 percent saying they went online "almost constantly." In a 2024 survey, U.S. teenagers reported that 95 percent have access to smartphone, spent 97 percent of their time online daily, and 48 percent is spent online "almost constantly".
Screen time and mental health
Some types of potentially problematic internet use are associated with psychiatric or behavioral problems such as depression, anxiety, hostility, aggression, and attention deficit hyperactivity disorder (ADHD). The studies could not determine if causal relationships exist; it was unclear, for example, whether people with depression might overuse the internet because they were already depressed, or if using the internet too much triggered the depression. Some studies also suggest that social media can have both negative and positive effects, depending on the specific context of the individual. While overuse of digital media has been associated with depressive symptoms, digital media may also be used in some situations to improve mood. Symptoms of ADHD have been positively correlated with digital media use in a large prospective study. The ADHD symptom of hyperfocus may cause affected individuals to overuse video games, social media, or online chatting; however the correlation between hyperfocus and problematic social media use is weak.
A 2018 review found associations between the self-reported mental health symptoms by users of the Chinese social media platform WeChat and excessive platform use. However, the motivations and usage patterns of WeChat users affected overall psychological health, rather than the amount of time spent using the platform.
An analysis of data from the Monitoring the Future survey, the Millennium Cohort Study, and the Youth Risk Behavior Surveillance System found that digital technology use (including, playing video games, watching television, using social media, etc.) accounted for only 0.4% of the variation in adolescent well-being. Additional research found little evidence for substantial negative associations for digital screen engagement and adolescent well-being. However, looking exclusively at the effect social media usage has on girls, there was a strong association between using social media and poor mental health.
The evidence, although of mainly low to moderate quality, shows a correlation between heavy screen time and a variety of health physical and mental health problems. However, moderate use of digital media is also correlated with benefits for young people in terms of social integration, mental health, and overall well-being. However, in some cases, moderate use of certain digital platforms has been associated with improved mental health.
A 2017 UK large-scale study of the "Goldilocks hypothesis"—of avoiding both too much and too little digital media use—was described as the "best quality" evidence to date by experts and non-government organisations (NGOs) reporting to a 2018 UK parliamentary committee. That study concluded that modest digital media use may have few adverse affects, and some positive associations in terms of well-being.
In a 2022 review, it was discovered that when it comes to adolescents' well-being that perhaps there is too much focus on locating a negative correlation between digital technologies and adolescents' well-being, If a negative correlation between the two are located the impact would potentially be minimal to the point where it would have little to no impact on adolescent well-being or quality of life.
Social media and mental health
Excessive time spent on social media may be more harmful than digital screen time as a whole, especially for young people. Some research found a "substantial" association between social media use and mental health issues, but most found only a weak or inconsistent relationship. Social media can have both positive and negative effects on mental health; whether the overall affect is harmful or helpful may depend on a variety of factors, including the quality and quantity of social media usage. In the case of over 65s, studies have found high levels of social media usage was associated with positive outcomes overall, such as flourishing, though it remains unclear if social media use is a causative factor.
Social media can be beneficial to individuals as a tool which if used correctly can bring about positive impacts to users online and offline. When it comes to social media, adolescence can benefit from its use by allowing users to build and maintain online and offline relationships, access information, connect to other in real time, and help adolescence to express themselves by creating and engaging with content. Social media can also be detrimental to users when used incorrectly. Adolescence who use social media can be exposed or placed at risk from the following: Cyberbullying, sexual predators, adult content, substance use, and content that uses unrealistic representations of people and lifestyles.
In a 2021 study, it was reported that adolescents who are associated with problematic media use are three times more likely to experience health complications such as irritability, nervousness, tiredness, and insomnia. Digital technologies tend to focus more on hedonic well-being, in which users are exposed to content that evokes joy and laughter towards positive content, to anger and sadness towards negative content. In turn these negative impacts on adolescence or any users of social media will only experience temporary impacts on mental well-being, which will not have a permanent effect on the user's quality of life and life satisfaction.
In 2023, it was discovered that 57 percent of teenagers between the ages of 13-17 would find it difficult to give up using social media, while the remaining 46 percent reported it would be easy. Older teenagers ranging from 15 to 17 years of age found it more difficult to give up social media, especially among teenage girls. There is a significant association between social media use and depression, with the association especially high for adolescent girls. When asked about the amount of time spent on social media teenagers reported that 55 percent have the right amount of time spent on social media. 35 percent of teenagers reported they spent too much time on social media, while 8 percent stated they spent too little time on social media.
Proposed diagnostic categories
Gaming disorder has been considered by the DSM-5 task force as warranting further study (as the subset internet gaming disorder), and was included in the ICD-11. Concerns have been raised by Aarseth and colleagues over this inclusion, particularly in regard to stigmatization of heavy gamers.
Christakis has asserted that internet addiction may be "a 21st century epidemic". In 2018, he commented that childhood Internet overuse may be a form of "uncontrolled experiment[s] on ... children". International estimates of the prevalence of internet overuse have varied considerably, with marked variations by nation. A 2014 meta-analysis of 31 nations yielded an overall worldwide prevalence of six percent. A different perspective in 2018 by Musetti and colleagues reappraised the internet in terms of its necessity and ubiquity in modern society, as a social environment, rather than a tool, thereby calling for the reformulation of the internet addiction model.
Some medical and behavioural scientists recommend adding a diagnosis of "social media addiction" (or similar) to the next Diagnostic and Statistical Manual of Mental Disorders update. A 2015 review concluded there was a probable link between basic psychological needs and social media addiction. "Social network site users seek feedback, and they get it from hundreds of people—instantly. It could be argued that the platforms are designed to get users 'hooked'."
Internet sex addiction, also known as cybersex addiction, has been proposed as a sexual addiction characterized by virtual internet sexual activity that causes serious negative consequences to one's physical, mental, social, and/or financial well-being. It may be considered a form of problematic internet use.
Related phenomena
Online problem gambling
A 2015 review found evidence of higher rates of mental health comorbidities, as well as higher amounts of substance use, among internet gamblers, compared to non-internet gamblers. Causation, however, has not been established. The review postulates that there may be differences in the cohorts between internet and land-based problem gamblers.
Cyberbullying
Cyberbullying, bullying or harassment using social media or other electronic means, has been shown to have effects on mental health. Victims may have lower self-esteem, increased suicidal ideation, decreased motivation for usual hobbies, and a variety of emotional responses, including being scared, frustrated, angry, anxious or depressed. These victims may also begin to distance themselves from friends and family members.
According to the EU Kids Online project, the incidence of cyberbullying across seven European countries in children aged increased from 8% to 12% between 2010 and 2014. Similar increases were shown in the United States and Brazil.
Media multitasking
Concurrent use of multiple digital media streams, commonly known as media multitasking, has been shown to be associated with depressive symptoms, social anxiety, impulsivity, sensation seeking, lower perceived social success and neuroticism. A 2018 review found that while the literature is sparse and inconclusive, overall, heavy media multitaskers also have poorer performance in several cognitive domains. One of the authors commented that the data does not "unambiguously show that media multitasking causes a change in attention and memory", therefore it is possible to argue that it is inefficient to multitask on digital media.
Distracted road use
In March 2023, Accident Analysis & Prevention published a systematic review of 47 samples across 45 studies investigating associations between problematic mobile phone use and road safety outcomes (including 32 samples of drivers, 9 samples of pedestrians, 5 samples with road use type unspecified, and 1 sample of motorcyclists and bicyclists) that found that problematic mobile phone use was associated with greater risk of simultaneous mobile phone use and road use and risk of vehicle collisions and pedestrian collisions or falls.
Noise-induced hearing loss
Assessment and treatment
Rigorous, evidence-based assessment of problematic digital media use is yet to be comprehensively established. This is due partially to a lack of consensus around the various constructs and lack of standardization of treatments. The American Academy of Pediatrics (AAP) has developed a Family Media Plan, intending to help parents assess and structure their family's use of electronic devices and media more safely. It recommends limiting entertainment screen time to two hours or less per day. The Canadian Paediatric Society produced a similar guideline. Ferguson, a psychologist, has criticised these and other national guidelines for not being evidence-based. Other experts, cited in a 2017 UNICEF Office of Research literature review, have recommended addressing potential underlying problems rather than arbitrarily enforcing screen time limits.
Different methodologies for assessing pathological internet use have been developed, mostly self-report questionnaires, but none have been universally recognised as a gold standard. For gaming disorder, both the American Psychiatric Association and the World Health Organization (through the ICD-11) have released diagnostic criteria.
There is some limited evidence of the effectiveness of cognitive behavioral therapy and family-based interventions for treatment. In randomized controlled trials, medications have not been shown to be effective. A 2016 study of 901 adolescents suggested mindfulness may assist in preventing and treating problematic internet use. A 2019 UK parliamentary report deemed parental engagement, awareness and support to be essential in developing "digital resilience" for young people, and to identify and manage the risks of harm online. Treatment centres have proliferated in some countries, and China and South Korea have treated digital dependence as a public health crisis, opening 300 and 190 centres nationwide, respectively. Other countries have also opened treatment centres.
NGOs, support and advocacy groups provide resources to people overusing digital media, with or without codified diagnoses, including the American Academy of Child and Adolescent Psychiatry.
A 2022 study outlines the mechanisms by which media-transmitted stressors affect mental well-being. Authors suggest a common denominator related to problems with the media's construction of reality is increased uncertainty, which leads to defensive responses and chronic stress in predisposed individuals.
Associated psychiatric disorders
ADHD
In April 2018, the International Journal of Environmental Research and Public Health published a systematic review of 24 studies researching associations between internet gaming disorder (IGD) and various psychopathologies that found an 85% correlation between IGD and ADHD. In October 2018, PNAS USA published a systematic review of four decades of research on the relationship between children and adolescents' screen media use and ADHD-related behaviours and concluded that a statistically small relationship between children's media use and ADHD-related behaviours exists. In November 2018, Cyberpsychology published a systematic review and meta-analysis of 5 studies that found evidence for a relationship between problematic smartphone use and impulsivity traits. In October 2020, the Journal of Behavioral Addictions published a systematic review and meta-analysis of 40 studies with 33,650 post-secondary student subjects that found a weak-to-moderate positive association between mobile phone addiction and impulsivity. In January 2021, the Journal of Psychiatric Research published a systematic review of 29 studies including 56,650 subjects that found that ADHD symptoms were consistently associated with gaming disorder and more frequent associations between inattention and gaming disorder than other ADHD scales.
In July 2021, Frontiers in Psychiatry published a meta-analysis reviewing 40 voxel-based morphometry studies and 59 functional magnetic resonance imaging studies comparing subjects with IGD or ADHD to control groups that found that IGD and ADHD subjects had disorder-differentiating structural neuroimage alterations in the putamen and orbitofrontal cortex (OFC) respectively, and functional alterations in the precuneus for IGD subjects and in the rewards circuit (including the OFC, the anterior cingulate cortex, and striatum) for both IGD and ADHD subjects. In March 2022, JAMA Psychiatry published a systematic review and meta-analysis of 87 studies with 159,425 subjects 12 years of age or younger that found a small but statistically significant correlation between screen time and ADHD symptoms in children. In April 2022, Developmental Neuropsychology published a systematic review of 11 studies where the data from all but one study suggested that heightened screen time for children is associated with attention problems. In July 2022, the Journal of Behavioral Addictions published a meta-analysis of 14 studies comprising 2,488 subjects aged 6 to 18 years that found significantly more severe problematic internet use in subjects diagnosed with ADHD to control groups.
In December 2022, European Child & Adolescent Psychiatry published a systematic literature review of 28 longitudinal studies published from 2011 through 2021 of associations between digital media use by children and adolescents and later ADHD symptoms and found reciprocal associations between digital media use and ADHD symptoms (i.e. that subjects with ADHD symptoms were more likely to develop problematic digital media use and that increased digital media use was associated with increased subsequent severity of ADHD symptoms). In May 2023, Reviews on Environmental Health published a meta-analysis of 9 studies with 81,234 child subjects that found a positive correlation between screen time and ADHD risk in children and that higher amounts of screen time in childhood may significantly contribute to the development of ADHD. In December 2023, the Journal of Psychiatric Research published a meta-analysis of 24 studies with 18,859 subjects with a mean age of 18.4 years that found significant associations between ADHD and problematic internet use, while Clinical Psychology Review published a systematic review and meta-analysis of 48 studies examining associations between ADHD and gaming disorder that found a statistically significant association between the disorders.
Anxiety
In April 2018, the International Journal of Environmental Research and Public Health published a systematic review of 24 studies researching associations between internet gaming disorder (IGD) and various psychopathologies that found a 92% correlation between IGD and anxiety and a 75% correlation between IGD and social anxiety. In August 2018, Wiley Stress & Health published a meta-analysis of 39 studies comprising 21,736 subjects that found a small-to-medium association between smartphone use and anxiety.
In December 2018, Frontiers in Psychiatry published a systematic review of 9 studies published after 2014 investigating associations between problematic social networking sites (SNS) use and comorbid psychiatric disorders that found a positive association between problematic SNS use and anxiety. In March 2019, the International Journal of Adolescence and Youth published a systematic review of 13 studies comprising 21,231 adolescent subjects aged 13 to 18 years that found that social media screen time, both active and passive social media use, the amount of personal information uploaded, and social media addictive behaviors all correlated with anxiety. In February 2020, Psychiatry Research published a systematic review and meta-analysis of 14 studies that found positive associations between problematic smartphone use and anxiety and positive associations between higher levels of problematic smartphone use and elevated risk of anxiety, while Frontiers in Psychology published a systematic review of 10 studies of adolescent or young adult subjects in China that concluded that the research reviewed mostly established an association between social networks use disorder and anxiety among Chinese adolescents and young adults.
In April 2020, BMC Public Health published a systematic review of 70 cross-sectional and longitudinal studies investigating moderating factors for associations for screen-based sedentary behaviors and anxiety symptoms among youth that found that while screen types was the most consistent factor, the body of evidence for anxiety symptoms was more limited than for depression symptoms. In October 2020, the Journal of Behavioral Addictions published a systematic review and meta-analysis of 40 studies with 33,650 post-secondary student subjects that found a weak-to-moderate positive association between mobile phone addiction and anxiety. In November 2020, Child and Adolescent Mental Health published a systematic review of research published between January 2005 and March 2019 on associations between SNS use and anxiety symptoms in subjects between ages of 5 to 18 years that found that increased SNS screen time or frequency of SNS use and higher levels of investment (i.e. personal information added to SNS accounts) were significantly associated with higher levels of anxiety symptoms.
In January 2021, Frontiers in Psychiatry published a systematic review of 44 studies investigating social media use and development of psychiatric disorders in childhood and adolescence that concluded that the research reviewed established a direct association between levels of anxiety, social media addiction behaviors, and nomophobia, longitudinal associations between social media use and increased anxiety, that fear of missing out and nomophobia are associated with severity of Facebook usage, and suggested that fear of missing out may trigger social media addiction and that nomophobia appears to mediate social media addiction. In March 2021, Computers in Human Behavior Reports published a systematic review of 52 studies published before May 2020 that found that social anxiety was associated with problematic social media use and that socially anxious persons used social media to seek social support possibly to compensate for a lack of offline social support. In June 2021, Clinical Psychology Review published a systematic review of 35 longitudinal studies published before August 2020 that found that evidence for longitudinal associations between screen time and anxiety among young people was lacking. In August 2021, a meta-analysis was presented at the 2021 International Conference on Intelligent Medicine and Health of articles published before January 2011 that found evidence for a negative impact of social media on anxiety.
In January 2022, The European Journal of Psychology Applied to Legal Context published a meta-analysis of 13 cross-sectional studies comprising 7,348 subjects that found a statistically significant correlation between cybervictimization and anxiety with a moderate-to-large effect size. In March 2022, JAMA Psychiatry published a systematic review and meta-analysis of 87 studies with 159,425 subjects 12 years of age or younger that found a small but statistically significant correlation between screen time and anxiety in children, while Adolescent Psychiatry published a systematic review of research published from June 2010 through June 2020 studying associations between social media use and anxiety among adolescent subjects aged 13 to 18 years that established that 78.3% of studies reviewed reported positive associations between social media use and anxiety. In April 2022, researchers in the Department of Communication at Stanford University performed a meta-analysis of 226 studies comprising 275,728 subjects that found a small but positive association between social media use and anxiety, while JMIR Mental Health published a systematic review and meta-analysis of 18 studies comprising 9,269 adolescent and young adult subjects that found a moderate but statistically significant association between problematic social media use and anxiety.
In May 2022, Computers in Human Behavior published a meta-analysis of 82 studies comprising 48,880 subjects that found a significant positive association between social anxiety and mobile phone addiction. In August 2022, the International Journal of Environmental Research and Public Health published a systematic review and meta-analysis of 16 studies comprising 8,077 subjects that established a significant association between binge-watching and anxiety. In November 2022, Cyberpsychology, Behavior, and Social Networking published a systematic review of 1,747 articles on problematic social media use that found a strong bidirectional relationship between social media use and anxiety. In March 2023, the Journal of Public Health published a meta-analysis of 27 studies published after 2014 comprising 120,895 subjects that found a moderate and robust association between problematic smartphone use and anxiety. In July 2023, Healthcare published a systematic review and meta-analysis of 16 studies that established correlation coefficients of 0.31 and 0.39 between nomophobia and anxiety and nomophobia and smartphone addiction respectively.
In September 2023, Frontiers in Public Health published a systematic review and meta-analysis of 37 studies comprising 36,013 subjects aged 14 to 24 years that found a positive and statistically significant association between problematic internet use and social anxiety, while BJPsych Open published a systematic review of 140 studies published from 2000 through 2020 found that social media use for more than 3 hours per day and passive browsing was associated with increased anxiety. In January 2024, the Journal of Computer-Mediated Communication published a meta-analysis of 141 studies comprising 145,394 subjects that found that active social media use was associated with greater symptoms of anxiety and passive social media use was associated with greater symptoms of social anxiety. In February 2024, Addictive Behaviors published a systematic review and meta-analysis of 53 studies comprising 59,928 subjects that found that problematic social media use and social anxiety are highly and positively correlated, while The Egyptian Journal of Neurology, Psychiatry and Neurosurgery published a systematic review of 15 studies researching associations between problematic social media use and anxiety in subjects from the Middle East and North Africa (including 4 studies with subjects exclusively between the ages of 12 and 19 years) that established that most studies found a significant association.
Autism
In September 2018, the Review Journal of Autism and Developmental Disorders published a systematic review of 47 studies published from 2005 to 2016 that concluded that associations between autism spectrum disorder (ASD) and screen time was inconclusive. In May 2019, the Journal of Developmental and Behavioral Pediatrics published a systematic review of 16 studies that found that children and adolescents with ASD are exposed to more screen time than typically developing peers and that the exposure starts at a younger age. In April 2021, Research in Autism Spectrum Disorders published a systematic review of 12 studies of video game addiction in ASD subjects that found that children, adolescents, and adults with ASD are at greater risk of video game addiction than those without ASD, and that the data from the studies suggested that internal and external factors (sex, attention and oppositional behavior problems, social aspects, access and time spent playing video games, parental rules, and game genre) were significant predictors of video game addiction in ASD subjects. In March 2022, the Review Journal of Autism and Developmental Disorders published a systematic review of 21 studies investigating associations between ASD, problematic internet use, and gaming disorder where the majority of the studies found positive associations between the disorders.
In August 2022, the International Journal of Mental Health and Addiction published a review of 15 studies that found that high rates of video game use in boys and young males with ASD was predominantly explained by video game addiction, but also concluded that greater video game use could be a function of ASD restricted interest and that video game addiction and ASD restricted interest could have an interactive relationship. In December 2022, the Review Journal of Autism and Developmental Disorders published a systematic review of 10 studies researching the prevalence of problematic internet use with ASD that found that ASD subjects had more symptoms of problematic internet use than control group subjects, had higher screen time online and an earlier age of first-time use of the internet, and also greater symptoms of depression and ADHD. In July 2023, Cureus published a systematic review of 11 studies that concluded that earlier and longer screen time exposure for children was associated with higher probability of a child "developing" ASD. In December 2023, JAMA Network Open published a meta-analysis of 46 studies comprising 562,131 subjects that concluded that while screen time may be a developmental cause of ASD in childhood, associations between ASD and screen time were not statistically significant when accounting for publication bias.
Bipolar disorder
In November 2018, Cyberpsychology published a systematic review and meta-analysis of 5 studies that found evidence for a relationship between problematic smartphone use and impulsivity traits. In October 2020, the Journal of Behavioral Addictions published a systematic review and meta-analysis of 40 studies with 33,650 post-secondary student subjects that found that a weak-to-moderate positive association between mobile phone addiction and impulsivity.
In April 2021, a meta-analysis of 3 studies comprising 9,142 subjects was presented at the International Conference on Big Data and Informatization Education that found that problematic internet use is a risk factor for bipolar disorder. In December 2023, the Journal of Psychiatric Research published a meta-analysis of 24 studies with 18,859 subjects with a mean age of 18.4 years that found significant associations between problematic internet use and impulsivity.
Depression
In April 2018, the International Journal of Environmental Research and Public Health published a systematic review of 24 studies researching associations between internet gaming disorder (IGD) and various psychopathologies that found an 89% correlation between IGD and depression. In July 2018, JMIR Mental Health published a systematic review of 11 studies investigating social media use and depression among lesbian, gay, and bisexual (LGB) users that found that while qualitative research found that social media use could lead to greater social support and less loneliness for LGB users, LGB users were more likely to be cyberbullied than heterosexual users, that cyberbullying of LGB users was associated with depression among victims, and constant monitoring of accounts by LGB users was also found to be a stressor associated with depression.
In December 2018, Frontiers in Psychiatry published a systematic review of 9 studies published after 2014 investigating associations between problematic SNS use and comorbid psychiatric disorders that found a positive association between problematic SNS use and depression. In March 2019, the International Journal of Adolescence and Youth published a systematic review of 13 studies comprising 21,231 adolescent subjects aged 13 to 18 years that found that social media screen time, both active and passive social media use, the amount of personal information uploaded, and social media addictive behaviors all correlated with depression. In April 2019, the Journal of Affective Disorders published a meta-analysis assessing associations between SNS use and higher levels of depression that found that greater SNS screen time and frequency of checking SNS accounts had small but statistically significant associations with higher levels of depression, that greater general social comparisons on SNS had a small to moderate association, and greater upward social comparisons on SNS had a moderate association. In November 2019, BMC Public Health published a systematic review and meta-analysis of 12 cross-sectional studies and 7 longitudinal studies that found that screen time-based sedentary behavior is associated with depression risk.
In January 2020, Translational Psychiatry published a meta-analysis of 12 prospective studies comprising 128,553 subjects that found that while sedentary behavior and depression risk had a significant positive association, television viewing and other mentally passive sedentary behaviors were positively associated with depression risk but computer use and other mentally active sedentary behaviors were not. In February 2020, Psychiatry Research published a systematic review and meta-analysis of 14 studies that found positive associations between problematic smartphone use and depression and positive associations between higher levels of problematic smartphone use and elevated risk of depression. Also in February 2020, Frontiers in Psychology published a systematic review of 10 studies of adolescent or young adult subjects in China that concluded that the research reviewed mostly established an association between social networks use disorder and depression among Chinese adolescents and young adults. In March 2020, the Review of General Psychology published a meta-analysis that found a small association between social networking service (SNS) use and self-reported depression. In April 2020, BMC Public Health published a systematic review of 70 cross-sectional and longitudinal studies investigating moderating factors for associations for screen-based sedentary behaviors and depression symptoms among youth that found that the most consistent factor was for screen type since television viewing was not as strongly associated with depression symptoms as other screen types.
In August 2020, the Journal of Medical Internet Research published an umbrella review of 7 systematic reviews on research investigating associations between depression and use of mobile technologies and social media by adolescents that concluded that while mobile technology and social media may promote social support, excess social comparison and personal involvement (i.e. increased exposure in general, exposure to specific content that promotes depressive symptoms, and the degree of personal information posted on social media) could be associated with symptoms of depression. In October 2020, the Journal of Affective Disorders published a meta-analysis of 12 studies with subjects aged 11 to 18 years that found a small but statistically significant positive correlation between social media use and depressive symptoms among adolescents, while the Journal of Behavioral Addictions published a systematic review and meta-analysis of 40 studies with 33,650 post-secondary student subjects that found a weak-to-moderate positive association between mobile phone addiction and depression. In November 2020, Child and Adolescent Mental Health published a systematic review of research published between January 2005 and March 2019 on associations between SNS use and depression in subjects between ages of 5 to 18 years that found that increased SNS screen time or frequency of SNS use and problematic and addictive SNS use were significantly associated with higher levels of depression symptoms.
In January 2021, Frontiers in Psychiatry published a systematic review of 44 studies investigating social media use and development of psychiatric disorders in childhood and adolescence that concluded that passive social media use (e.g. browsing other user photos or scrolling through comments or news feeds) and depression are bidirectionally associated and that problematic social media use and depressive symptoms are mediated by social comparisons. In February 2021, Research on Child and Adolescent Psychopathology published a meta-analysis of 62 studies comprising 451,229 subjects that found SNS screen time and SNS use intensity to have weak but statistically significant associations with depression symptoms, while problematic SNS use was found to have a moderate association with depression symptoms. In March 2021, Youth & Society published a systematic review of 9 studies that found an association between SNS use and adolescent subjective well-being including mood, but that the results over whether the association was positive or negative were mixed. In April 2021, the Journal of Affective Disorders published a systematic review and meta-analysis of 92 studies comprising 15,148 subjects across 25 countries investigating associations between depression and internet gaming disorder found that one-third of the IGD subjects had been diagnosed with depression and major severe depressive symptoms were found in IGD subjects globally without a formal diagnosis in comparison to the general population.
In May 2021, Current Psychology published a meta-analysis of 55 studies comprising 80,533 subjects that found a small but positive and statistically significant association between SNS use and self-reported depression symptoms. In June 2021, Clinical Psychology Review published a systematic review of 35 longitudinal studies published before August 2020 that found that an association between screen time and subsequent depressive symptoms among young people was small and varied by device type and use. In July 2021, Translational Medicine Communications published a systematic review of 9 studies published between October 2010 and December 2018 with Instagram user subjects between the ages of 19 and 35 years that found an association between Instagram use and depression symptoms. In January 2022, The European Journal of Psychology Applied to Legal Context published a meta-analysis of 13 cross-sectional studies comprising 7,348 subjects that found a statistically significant correlation between cybervictimization and depression with a moderate-to-large effect size. In February 2022, the International Journal of Social Psychiatry published a meta-analysis of 131 studies comprising 244,676 subjects that found a moderate mean correlation between problematic social media use and depression.
In March 2022, Computers in Human Behavior published a systematic review and meta-analysis of 531 cross-sectional or longitudinal studies with subjects aged 10 to 24 years that found a small bidirectional association between online media use and depressive symptoms and that the effect size did not differ between general internet use, smartphone use, social media use, or online gaming, but also found that studies that measured online media use with media addiction scales rather than by screen time found significantly greater associations. Also in March 2022, JAMA Psychiatry published a systematic review and meta-analysis of 87 studies with 159,425 subjects 12 years of age or younger that found a small but statistically significant correlation between screen time and depression in children, while Adolescent Psychiatry published a systematic review of research published from June 2010 through June 2020 studying associations between social media use and depression among adolescent subjects aged 13 to 18 years that established that 82.6% of studies reviewed reported positive associations between social media use and depression. In April 2022, the International Journal of Environmental Research and Public Health published a meta-analysis of 21 cross-sectional studies and 5 longitudinal studies comprising 55,340 adolescent subjects that found that social media screen time had a linear dose–response association with depression risk among adolescents and that depression risk increased by 13% for each additional hour of social media screen time.
Also in April 2022, researchers in the Department of Communication at Stanford University performed a meta-analysis of 226 studies comprising 275,728 subjects that found a small but positive association between social media use and depression, while JMIR Mental Health published a systematic review and meta-analysis of 18 studies comprising 9,269 adolescent and young adult subjects that found a moderate but statistically significant association between problematic social media use and depression. In August 2022, the International Journal of Environmental Research and Public Health published a systematic review and meta-analysis of 16 studies comprising 8,077 subjects that established a significant association between binge-watching and depression and a stronger association between binge-watching and depression was found during the COVID-19 pandemic than pre-pandemic. In November 2022, Cyberpsychology, Behavior, and Social Networking published a systematic review of 1,747 articles on problematic social media use that found a strong bidirectional relationship between social media use and depression. In December 2022, Frontiers in Psychiatry published a meta-analysis of 18 cohort studies comprising 241,398 subjects that found that screen time is a predictor of depressive symptoms. In March 2023, the Journal of Public Health published a meta-analysis of 27 studies published after 2014 comprising 120,895 subjects that found a moderate and robust association between problematic smartphone use and depression.
In April 2023, Trauma, Violence, & Abuse published a systematic review and meta-analysis of 17 studies comprising 79,202 adolescent subjects between the ages of 10 and 19 years that found that depression was three times more common among cyberbullying victims than control groups. In July 2023, Current Psychology published a meta-analysis of 38 studies comprising 14,935 subjects in Turkey that found a small but positive association between problematic social media use and depression. In September 2023, Clinical Psychological Science published a preregistered review and meta-analysis of 34 articles published between 2018 and 2020 studying associations between adolescent depression and social media use to identify the proportion of samples taken from the Global North and Global South, and found that more than 70% examined Global North populations and that associations in the Global North were positive and significant while associations in the Global South were null and non-significant. In September 2023, BJPsych Open published a systematic review of 140 studies published from 2000 through 2020 that found that social media use for more than 3 hours per day and passive browsing was associated with increased depression in children, adolescents, and young adults. In February 2024, The Egyptian Journal of Neurology, Psychiatry and Neurosurgery published a systematic review of 15 studies researching associations between problematic social media use and depression in subjects from the Middle East and North Africa (including 4 studies with subjects exclusively between the ages of 12 and 19 years) that established that most studies found a significant association.
Insomnia
In August 2018, Sleep Science and Practice published a systematic review and meta-analysis of 19 studies comprising 253,904 adolescent subjects that found that excessive technology use had a strong and consistent association with reduced sleep duration and prolonged sleep onset latency for adolescents 14 years of age or older. Also in August 2018, Sleep Science published a systematic review of 12 studies investigating associations between exposure to video games, sleep outcomes, and post-sleep cognitive abilities that found the data present in the studies indicated associations between a reduction in sleep duration, increased sleep onset latency, modifications to rapid eye movement sleep and slow-wave sleep, increased sleepiness and self-perceived fatigue, and impaired post-sleep attention span and verbal memory. In October 2019, Sleep Medicine Reviews published a systematic review and meta-analysis of 23 studies comprising 35,684 subjects that found a statistically significant odds ratio for sleep problems and reduced sleep duration for subjects with internet addiction. In February 2020, Psychiatry Research published a systematic review and meta-analysis of 14 studies that found positive associations between problematic smartphone use and poor sleep quality and between higher levels of problematic smartphone use and elevated risk of poor sleep quality.
Also in February 2020, Sleep Medicine Reviews published a systematic review of 31 studies examining associations between screen time and sleep outcomes in children younger than 5 years and found that screen time is associated with poorer sleep outcomes for children under the age of 5, with meta-analysis only confirming poor sleep outcomes among children under 2 years. In March 2020, Developmental Review published a systematic review of 9 studies that found a weak-to-moderate association between sleep quantity and quality and problematic smartphone use among adolescents. In October 2020, the International Journal of Environmental Research and Public Health published a systematic review and meta-analysis of 80 studies that found that greater screen time was associated with shorter sleep duration among toddlers and preschoolers, while the Journal of Behavioral Addictions published a systematic review and meta-analysis of 40 studies with 33,650 post-secondary student subjects that found a weak-to-moderate positive association between mobile phone addiction and poor sleep quality. In April 2021, Sleep Medicine Reviews published a systematic review of 36 cross-sectional studies and 6 longitudinal studies that found that 24 of the cross-sectional studies and 5 of the longitudinal studies established significant associations between more frequent social media use and poor sleep outcomes.
In June 2021, Frontiers in Psychiatry published a systematic review and meta-analysis of 34 studies comprising 51,901 subjects that established significant associations between problematic gaming and sleep duration, poor sleep quality, daytime sleepiness, and other sleep problems. In September 2021, BMC Public Health published a systematic review of 49 studies investigating associations between electronic media use and various sleep outcomes among children and adolescents 15 years of age or younger that found a strong association with sleep duration and stronger evidence for an association with sleep duration between the ages of 6 and 15 years than for 5 years of age or younger, while evidence for associations between electronic media use with other sleep outcomes was more inconclusive. In December 2021, Frontiers in Neuroscience published a systematic review of 12 studies published from January 2000 to April 2020 that found that adult subjects with higher gaming addiction scores were more likely to have shorter sleep quantity, poorer sleep quality, delayed sleep timing, and greater daytime sleepiness and insomnia scores than subjects with lower gaming addiction scores and non-gamer subjects. In January 2022, Early Childhood Research Quarterly published a systematic review and meta-analysis of 26 studies that found a weak but statistically significant association with increased smartphone and tablet computer use and poorer sleep in early childhood.
In May 2022, the Journal of Affective Disorders published a meta-analysis of 29 studies comprising 20,041 subjects that found a weak-to-moderate association between mobile phone addiction and sleep disorder and that adolescents with mobile phone addiction were at higher risk of developing sleep disorder. In August 2022, the International Journal of Environmental Research and Public Health published a systematic review and meta-analysis of 16 studies comprising 8,077 subjects that established a significant association between binge-watching and sleep problems and a stronger association between binge-watching and sleep problems was found during the COVID-19 pandemic than pre-pandemic. In October 2022, Reports in Public Health published a systematic review of 23 studies that found that excessive use of digital screens by adolescents was associated with poor sleep quality, nighttime awakenings, long sleep latency, and daytime sleepiness. In December 2022, Sleep Epidemiology published a systematic review of 18 studies investigating associations between sleep problems and screen time during COVID-19 lockdowns that found that the increased screen time during the lockdowns negatively impacted sleep duration, sleep quality, sleep onset latency, and wake time. In March 2023, the Journal of Clinical Sleep Medicine published a systematic review and meta-analysis of 17 studies comprising 36,485 subjects that found that smartphone overuse was closely associated with self-reported poor sleep quality, sleep deprivation, and prolonged sleep latency.
In April 2023, Sleep Medicine Reviews published a systematic review of 42 studies that found digital media use to be associated with shorter sleep duration and poorer sleep quality and bedtime or nighttime use with poor sleep outcomes, but only found associations for general screen use, mobile phone use, computer and internet use, internet, and social media and not for television, game console, and tablet use. In July 2023, Healthcare published a systematic review and meta-analysis of 16 studies that established a correlation coefficient of 0.56 between nomophobia and insomnia. In September 2023, PLOS One published a systematic review and meta-analysis of 16 studies of smartphone addiction and sleep among medical students found that 57% of subjects had poor sleep and 39% of subjects had smartphone addiction with a correlation index of 0.3, while Computers in Human Behavior published a meta-analysis of 23 longitudinal studies comprising 116,431 adolescent subjects that found that adolescent screen time with computers, smartphones, social media, and television are positively associated with negative impacts on sleep health later in life.
Narcissism
In April 2018, a meta-analysis published in the Journal of Personality found that the positive correlation between grandiose narcissism and social networking site (SNS) usage was replicated across platforms (including Facebook and Twitter). In July 2018, a meta-analysis published in Psychology of Popular Media found that grandiose narcissism positively correlated with time spent on social media, frequency of status updates, number of friends or followers, and frequency of posting self-portrait digital photographs. In March 2020, the Review of General Psychology published a meta-analysis that found a small-to-moderate association between SNS use and narcissism. In June 2020, Addictive Behaviors published a systematic review finding a consistent, positive, and significant correlation between grandiose narcissism and problematic social media use.
OCD
In April 2018, the International Journal of Environmental Research and Public Health published a systematic review of 24 studies researching associations between internet gaming disorder (IGD) and various psychopathologies that found a significant correlation between IGD and obsessive–compulsive disorder symptoms in 3 of 4 studies.
Mental health benefits
Individuals with mental illness can develop social connections over social media, that may foster a sense of social inclusion in online communities. People with mental illness may share personal stories in a perceived safer space, as well as gaining peer support for developing coping strategies.
A mediated model research study was done to see the effects of social media use on psychological well-being both in positive and negative ways. Although social media has a stigma of negative influence, this study looks into the positive as well. The positive influence of social media resulted in the feeling of connectedness and relevance with others. It is a way to interact with people from a far and may send a sense of relief of social isolation.
Research published in 2024 investigated the impact of 'labels' on mental health. The participants received indications through labels whether specific webpages were likely to make them feel better or worse. The labeling system influenced participants' preferences and helped them evaluate the best choices when presented with relevant information. The results suggested that digital labels can be a useful tool to encourage healthy behaviors and improving behaviour, demonstrating the potential of technology to improve mental health.
People with mental illness are likely to report avoiding stigma and gaining further insight into their mental health condition by using social media. This comes with the risk of unhealthy influences, misinformation, and delayed access to traditional mental health outlets.
Other benefits include connections to supportive online communities, including illness or disability specific communities, as well as the LGBTQIA community. Young cancer patients have reported an improvement in their coping abilities due to their participation in an online community. The uses of social media for healthcare communication include providing reducing stigma and facilitating dialogue between patients and between patients and health professionals.
Furthermore, in children, the educational benefits of digital media use are well established. For example, screen-based programs can help increase both independent and collaborative learning. A variety of quality apps and software can also decrease learning gaps and increase skill in certain educational subjects.
Other disciplines
Digital anthropology
Daniel Miller from University College London has contributed to the study of digital anthropology, especially ethnographic research on the use and consequences of social media and smartphones as part of the everyday life of ordinary people around the world. He notes the effects of social media are very specific to individual locations and cultures. He contends "a layperson might dismiss these stories as superficial. But the anthropologist takes them seriously, empathetically exploring each use of digital technologies in terms of the wider social and cultural context."
Digital anthropology is a developing field which studies the relationship between humans and digital-era technology. It aims to consider arguments in terms of ethical and societal scopes, rather than simply observing technological changes. Brian Solis, a digital analyst and anthropologist, stated in 2018, "we've become digital addicts: it's time to take control of technology and not let tech control us".
Digital sociology
Digital sociology explores how people use digital media using several research methodologies, including surveys, interviews, focus groups, and ethnographic research. It intersects with digital anthropology, and studies cultural geography. It also investigates longstanding concerns, and contexts around young people's overuse of "these technologies, their access to online pornography, cyber bullying or online sexual predation".
A 2012 cross-sectional sociological study in Turkey showed differences in patterns of internet use that related to levels of religiosity in 2,698 subjects. With increasing religiosity, negative attitudes towards internet use increased. Highly religious people showed different motivations for internet use, predominantly searching for information. A study of 1,296 Malaysian adolescent students found an inverse relationship between religiosity and internet addiction tendency in females, but not males.
A 2018 review published in Nature considered that young people may have different experiences online, depending on their socio-economic background, noting lower-income youths may spend up to three hours more per day using digital devices, compared to higher-income youths. They theorized that lower-income youths, who are already vulnerable to mental illness, may be more passive in their online engagements, being more susceptible to negative feedback online, with difficulty self-regulating their digital media use. It concluded that this may be a new form of digital divide between at-risk young people and other young people, pre-existing risks of mental illness becoming amplified among the already vulnerable population.
Neuroscience
A 2018 neuroscientific review published in Nature found the density of the amygdala, a brain region involved in emotional processing, is related to the size of both offline and online social networks in adolescents. They considered that this and other evidence "suggests an important interplay between actual social experiences, both offline and online, and brain development". The authors postulated that social media may have benefits, namely social connections with other people, as well as managing impressions people have of other people such as "reputation building, impression management, and online self-presentation". It identified "adolescence [as] a tipping point in development for how social media can influence their self-concept and expectations of self and others", and called for further study into the neuroscience behind digital media use and brain development in adolescence. Although brain-imaging modalities are under study, neuroscientific findings in individual studies often fail to be replicated in future studies, similar to other behavioural addictions; as of 2017, the exact biological or neural processes that could lead to excessive digital media use are unknown.
Impact on cognition
There is research and development about the cognitive impacts of smartphones and digital technology. A group reported that, contrary to widespread belief, scientific evidence does not show that these technologies harm biological cognitive abilities and that they instead only change predominant ways of cognition – such as a reduced need to remember facts or conduct mathematical calculations by pen and paper outside contemporary schools. However, some activities – like reading novels – that require long focused attention-spans and do not feature ongoing rewarding stimulation may become more challenging in general. How extensive online media usage impacts cognitive development in youth is under investigation and impacts may substantially vary by the way and which technologies are being used – such as which and how digital media platforms are being used – and how these are designed. Impacts may vary to a degree such studies have not yet taken into account and may be modulatable by the design, choice and use of technologies and platforms, including by the users themselves.
A study suggests that in children aged 8–12 during two years, time digital gaming or watching digital videos can be positively correlated with measures intelligence, albeit correlations with overall screen time (including social media, socializing and TV) were not investigated and 'time gaming' did not differentiate between categories of video games (e.g. shares of games' platform and genre), and digital videos did not differentiate between categories of videos.
Impact on social life
Worldwide adolescent loneliness in contemporary schools and depression increased substantially after 2012 and a study found this to be associated with smartphone access and Internet use.
Mitigation
Industry
Several technology firms have implemented changes intending to mitigate the adverse effects of excessive use of their platforms.
In December 2017, Facebook admitted passive consumption of social media could be harmful to mental health, although they said active engagement can have a positive effect. In January 2018, the platform made major changes to increase user engagement. In January 2019, Facebook's then head of global affairs, Nick Clegg, responding to criticisms of Facebook and mental health concerns, stated they would do "whatever it takes to make this environment safer online especially for youngsters". Facebook admitted "heavy responsibilities" to the global community, and invited regulation by governments. In 2018 Facebook and Instagram announced new tools that they asserted may assist with overuse of their products. In 2019, Instagram, which has been investigated specifically in one study in terms of addiction, began testing a platform change in Canada to hide the number of "likes" and views that photos and videos received in an effort to create a "less pressurised" environment. It then continued this trial in Australia, Italy, Ireland, Japan, Brazil and New Zealand before extending the experiment globally in November of that year. The platform also developed artificial intelligence to counter cyberbullying.
In 2018, Alphabet Inc. released an update for Android smartphones, including a dashboard app enabling users to set timers on application use. Apple Inc. purchased a third-party application and then incorporated it in iOS 12 to measure "screen time". Journalists have questioned the functionality of these products for users and parents, as well as the companies' motivations for introducing them. Alphabet has also invested in a mental health specialist, Quartet, which uses machine learning to collaborate and coordinate digital delivery of mental health care.
Two activist investors in Apple Inc voiced concerns in 2018 about the content and amount of time spent by youth. They called on Apple Inc. to act before regulators and consumers potentially force them to do so. Apple Inc. responded that they have, "always looked out for kids, and [they] work hard to create powerful products that inspire, entertain, and educate children while also helping parents protect them online". The firm is planning new features that they asserted may allow them to play a pioneering role in regard to young people's health.
Public sector
In China, Japan, South Korea and the United States, governmental efforts have been enacted to address issues relating to digital media use and mental health.
China's Ministry of Culture has enacted several public health efforts from as early as 2006 to address gaming and internet-related disorders. In 2007, an "Online Game Anti-Addiction System" was implemented for minors, restricting their use to 3 hours or less per day. The ministry also proposed a "Comprehensive Prevention Program Plan for Minors' Online Gaming Addiction" in 2013, to promulgate research, particularly on diagnostic methods and interventions. China's Ministry of Education in 2018 announced that new regulations would be introduced to further limit the amount of time spent by minors in online games. In response, Tencent, the owner of WeChat and the world's largest video game publisher, restricted the amount of time that children could spend playing one of its online games, to one hour per day for children 12 and under, and two hours per day for children aged . Effective 2 September 2023, those under the age of 18 can no longer access the Internet on their mobile device between 10 pm and 6 am without parental bypass. Smartphone usage is similarly capped by default at 40 minutes a day for children younger than eight and at two hours for 16- and 17-year-olds.
Japan's Ministry of Internal Affairs and Communications coordinates Japanese public health efforts in relation to problematic internet use and gaming disorder. Legislatively, the Act on Development of an Environment that Provides Safe and Secure Internet Use for Young People was enacted in 2008, to promote public awareness campaigns, and support NGOs to teach young people safe internet use skills.
South Korea has eight government ministries responsible for public health efforts in relation to internet and gaming disorders. A review article published in Prevention Science in 2018 stated that the "region is unique in that its government has been at the forefront of prevention efforts, particularly in contrast to the United States, Western Europe, and Oceania." Efforts are coordinated by the Ministry of Science and ICT, and include awareness campaigns, educational interventions, youth counseling centres, and promoting healthy online culture.
In May 2023, the United States' Surgeon general took the rare measure of issuing an advisory on Social media and mental health. In October, 41 U.S. states commenced legal proceedings against Meta. This included the attorneys general of 33 states filing a combined lawsuit over concerns about the addictive nature of Instagram and its impact on the mental health of young people. In November 2024, Australia passed the world's first ban on social media for under-16s.
Digital mental health care
Digital technologies have also provided opportunities for delivery of mental health care online; benefits have been found with computerized cognitive behavioral therapy for depression and anxiety. Mindfulness based online intervention has been shown to have small to moderate benefits on mental health. The greatest effect size was found for the reduction of psychological stress. Benefits were also found regarding depression, anxiety, and well-being.
The Lancet commission on global mental health and sustainability report from 2018 evaluated both benefits and harms of technology. It considered the roles of technologies in mental health, particularly in public education; patient screening; treatment; training and supervision; and system improvement. A study in 2019 published in Front Psychiatry in the National Center for Biotechnology Information states that despite proliferation of many mental health apps there has been no "equivalent proliferation of scientific evidence for their effectiveness."
Steve Blumenfield and Jeff Levin-Scherz, writing in the Harvard Business Review, claim that "most published studies show telephonic mental health care is as effective as in-person care in treating depression, anxiety and obsessive-compulsive disorder." The also cite a 2020 study done with the Veterans Administration as evidence of this as well.
See also
Computer-induced medical problems
Evolutionary psychiatry
Instagram
Screen time
Social aspects of television
References
Further reading
Woods, H. C., & Scott, H. (2016). #Sleepyteens: Social media use in adolescence is associated with poor sleep quality, anxiety, depression and low self‐esteem. Journal of Adolescence, 51(1), 41–49. https://doi.org/10.1016/j.adolescence.2016.05.008
Jones, A., Hook, M., Podduturi, P., McKeen, H., Beitzell, E., & Liss, M. (2022). Mindfulness as a mediator in the relationship between social media engagement and depression in young adults. Personality and Individual Differences, 185. https://doi.org/10.1016/j.paid.2021.111284
White-Gosselin, C.-É., & Poulin, F. (2022). Associations between young adults' social media addiction, relationship quality with parents, and internalizing problems: A path analysis model. Canadian Journal of Behavioural Science / Revue Canadienne Des Sciences Du Comportement. https://doi.org/10.1037/cbs0000326
Hammad, M. A., & Alqarni, T. M. (2021). Psychosocial effects of social media on the Saudi society during the Coronavirus Disease 2019 pandemic: A cross-sectional study. PLoS ONE, 16(3). https://doi.org/10.1371/journal.pone.0248811
Huang, Chiungjung. “A Meta-Analysis of the Problematic Social Media Use and Mental Health.” Https://Doi.Org/10.1177/0020764020978434, December 9, 2020. https://doi.org/10.1177/0020764020978434.
Weigle, Paul E., and Pamela Hurst-Della Pietra. “Children and Screens: Youth Digital Media Use and Mental Health Outcomes.” Journal of the American Academy of Child & Adolescent Psychiatry 60, no. 10 (October 2, 2021): S297–S297. https://doi.org/10.1016/j.jaac.2021.07.700.
External links
Anthropology of Social Media: Why We Post, University College London, Free online five-week course, asking "What are the consequences of social media?"
Social Media Use and Mental Health: A Review – ongoing review curated by Jean Twenge & Jonathan Haidt.
Cultural anthropology
Cyberspace
Technology in society
Child and adolescent psychiatry
Educational psychology
Mental health | Digital media use and mental health | [
"Technology"
] | 13,885 | [
"Information technology",
"Cyberspace"
] |
59,602,278 | https://en.wikipedia.org/wiki/Patinho%20Feio | Patinho Feio (Portuguese for "Ugly Duckling", in reference to the fairy tale) was the first minicomputer designed and manufactured entirely in Brazil. It was made between 1971 and 1972 in the Polytechnic School of the University of São Paulo by the Digital Systems Laboratory (currently called Department of Computer Engineering and Digital Systems).
Technology
Patinho Feio was an 8-bit minicomputer with a memory of 8 kB and an instruction cycle of 2 microseconds. It was programmed in assembly language.
See also
Zezinho
References
Computers designed in Brazil
Minicomputers
Early microcomputers
One-of-a-kind computers
University of São Paulo | Patinho Feio | [
"Technology"
] | 139 | [
"Computing stubs",
"Computer hardware stubs"
] |
59,603,661 | https://en.wikipedia.org/wiki/Interconnect%20%28integrated%20circuits%29 | In integrated circuits (ICs), interconnects are structures that connect two or more circuit elements (such as transistors) together electrically. The design and layout of interconnects on an IC is vital to its proper function, performance, power efficiency, reliability, and fabrication yield. The material interconnects are made from depends on many factors. Chemical and mechanical compatibility with the semiconductor substrate and the dielectric between the levels of interconnect is necessary, otherwise barrier layers are needed. Suitability for fabrication is also required; some chemistries and processes prevent the integration of materials and unit processes into a larger technology (recipe) for IC fabrication. In fabrication, interconnects are formed during the back-end-of-line after the fabrication of the transistors on the substrate.
Interconnects are classified as local or global interconnects depending on the signal propagation distance it is able to support. The width and thickness of the interconnect, as well as the material from which it is made, are some of the significant factors that determine the distance a signal may propagate. Local interconnects connect circuit elements that are very close together, such as transistors separated by ten or so other contiguously laid out transistors. Global interconnects can transmit further, such as over large-area sub-circuits. Consequently, local interconnects may be formed from materials with relatively high electrical resistivity such as polycrystalline silicon (sometimes silicided to extend its range) or tungsten. To extend the distance an interconnect may reach, various circuits such as buffers or restorers may be inserted at various points along a long interconnect.
Interconnect properties
The geometric properties of an interconnect are width, thickness, spacing (the distance between an interconnect and another on the same level), pitch (the sum of the width and spacing), and aspect ratio, or AR, (the thickness divided by width). The width, spacing, AR, and ultimately, pitch, are constrained in their minimum and maximum values by design rules that ensure the interconnect (and thus the IC) can be fabricated by the selected technology with a reasonable yield. Width is constrained to ensure minimum width interconnects do not suffer breaks, and maximum width interconnects can be planarized by chemical mechanical polishing (CMP). Spacing is constrained to ensure adjacent interconnects can be fabricated without any conductive material bridging. Thickness is determined solely by the technology, and the aspect ratio, by the chosen width and set thickness. In technologies that support multiple levels of interconnects, each group of contiguous levels, or each level, has its own set of design rules.
Before the introduction of CMP for planarizing IC layers, interconnects had design rules that specified larger minimum widths and spaces than the lower level to ensure that the underlying layer's rough topology did not cause breaks in the interconnect formed on top. The introduction of CMP has made finer geometries possible.
The AR is an important factor. In technologies that form interconnect structures with conventional processes, the AR is limited to ensure that the etch creating the interconnect, and the dielectric deposition that fills the voids in between interconnects with dielectric, can be done successfully. In those that form interconnect structures with damascene processes, the AR must permit successful etch of the trenches, deposition of the barrier metal (if needed) and interconnect material.
Interconnect layout are further restrained by design rules that apply to collections of interconnects. For a given area, technologies that rely on CMP have density rules to ensure the whole IC has an acceptable variation in interconnect density. This is because the rate at which CMP removes material depends on the material's properties, and great variations in interconnect density can result in large areas of dielectric which can dish, resulting in poor planarity. To maintain acceptable density, dummy interconnects (or dummy wires) are inserted into regions with spare interconnect density.
Historically, interconnects were routed in straight lines, and could change direction by using sections aligned 45° away from the direction of travel. As IC structure geometries became smaller, to obtain acceptable yields, restrictions were imposed on interconnect direction. Initially, only global interconnects were subject to restrictions; were made to run in straight lines aligned eastwest or northsouth. To allow easy routing, alternate levels of interconnect ran in the same alignment, so that changes in direction were achieved by connecting to a lower or upper level of interconnect though a via. Local interconnects, especially the lowest level (usually polysilicon) could assume a more arbitrary combination of routing options to attain the a higher packing density.
Materials
In silicon ICs, the most commonly used semiconductor in ICs, the first interconnects were made of aluminum. Aluminum was an ideal material for interconnects due to its ease of deposition and good adherence to silicon and silicon dioxide. Al interconnects are deposited by physical vapor deposition or chemical vapor deposition methods. They were originally patterned by wet etching, and later by various dry etching techniques.
Initially, pure aluminum was used but by the 1970s, substrate compatibility, junction spiking and reliability concerns (mostly concerning electromigration) forced the use of aluminum-based alloys containing silicon, copper, or both. By the late 1990s, the high resistivity of aluminum, coupled with the narrow widths of the interconnect structures forced by continuous feature size downscaling, resulted in prohibitively high resistance in interconnect structures. This forced aluminum's replacement by copper interconnects.
In gallium arsenide (GaAs) ICs, which have been mainly used in application domains (e.g. monolithic microwave ICs) different to those of silicon, the predominant material used for interconnects is gold.
Performance enhancements
To reduce the delay penalty caused by parasitic capacitance, the dielectric material used to insulate adjacent interconnects, and interconnects on different levels (the inter-level dielectric [ILD]), should have a dielectric constant that is as close to 1 as possible. A class of such materials, Low-κ dielectrics, were introduced during the late 1990s and early 2000s for this purpose. As of January 2019, the most advanced materials reduce the dielectric constant to very low levels through highly porous structures, or through the creation of substantial air or vacuum pockets (air gap dielectric). These materials often have low mechanical strength and are restricted to the lowest level or levels of interconnect as a result. The high density of interconnects at the lower levels, along with the minimal spacing, helps support the upper layers. Intel introduced air-gap dielectric in its 14nm technology in 2014.
Multi-level interconnects
IC with complex circuits require multiple levels of interconnect to form circuits that have minimal area. As of 2018, the most complex ICs may have over 15 layers of interconnect. Each level of interconnect is separated from each other by a layer of dielectric. To make vertical connections between interconnects on different levels, vias are used. The top-most layers of a chip have the thickest and widest and most widely separated metal layers, which make the wires on those layers have the least resistance and smallest RC time constant, so they are used for power and clock distribution networks. The bottom-most metal layers of the chip, closest to the transistors, have thin, narrow, tightly-packed wires, used only for local interconnect. Adding layers can potentially improve performance, but adding layers also reduces yield and increases manufacturing costs. ICs with a single metal layer typically use the polysilicon layer to "jump across" when one signal needs to cross another signal.
The process used to form DRAM capacitors creates a rough and hilly surface, which makes it difficult to add metal interconnect layers and still maintain good yield.
In 1998, state-of-the-art DRAM processes had four metal layers, while state-of-the-art logic processes had seven metal layers.
In 2002, five or six layers of metal interconnect was common.
In 2009, 1Gbit DRAM typically had three layers of metal interconnect; tungsten for the first layer and aluminum for the upper layers.
See also
Antenna effect
Bonding pad
Carbon nanotubes in interconnects
Interconnect bottleneck
Optical interconnect
Parasitic extraction
References
Integrated circuits | Interconnect (integrated circuits) | [
"Technology",
"Engineering"
] | 1,855 | [
"Computer engineering",
"Integrated circuits"
] |
59,604,015 | https://en.wikipedia.org/wiki/NGC%204665 | NGC 4665, also catalogued as NGC 4624 and NGC 4664, is a barred lenticular or spiral galaxy located in the constellation Virgo. It is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 4665 is about 75,000 light years across. NGC 4665 lies 2 and 3/4 degrees east-south east of Delta Virginis and 50 arcminutes southwest of 35 Virginis. It can be viewed through a moderately sized telescope with 23x magnification, forming a pair with an 11th magnitude star 1.5 arcminutes southwest. It is part of the Herschel 400 Catalogue.
Observation history
It was discovered by William Herschel on February 23, 1784, however, he noted a location 10 arcminutes off the galaxy, where there is no object. It was observed by William Herschel again on April 30, 1786, noting the correct coordinates, and he misidentified it as another nebula. The fact that they are the same object was noted by John Louis Emil Dreyer in 1912 in the corrections of the New General Catalogue. It was also recorded independently on April 9, 1828 by John Herschel.
Physical characteristics
NGC 4665 has a luminous, slightly elliptical bulge and a prominent bar with high surface brightness. The isophotes appear boxy at the end of the bar. The total bar length is estimated to be near 3 kpc. The bar is slightly twisted, turning near 12 degrees along its axis. Two diffuse, faint arms emerge from each side of the bar and form a pseudoring. The surface brightness of the arms is higher near the bar. The southern arm appears a bit stronger. An arch feature is observed at the east side of the galaxy that could be a partial outer dusty ring. The outer isophotes are elliptical. The total mass of molecular gas is less than .
NGC 4665 belongs to the NGC 4636 group. Other members of the group include NGC 4457, NGC 4586, NGC 4587, NGC 4600, NGC 4636, and NGC 4688. These galaxies, along with NGC 4753, Messier 61 and their groups form the southern boundary of the Virgo cluster. It can be difficult to determine which galaxies belong to which group, especially around the southern edge of the Virgo cluster where there is a confusion of galaxies at different distances.
References
External links
NGC 4665 on SIMBAD
Barred spiral galaxies
Barred lenticular galaxies
Virgo (constellation)
4665
07924
42970
Astronomical objects discovered in 1784
Discoveries by William Herschel | NGC 4665 | [
"Astronomy"
] | 566 | [
"Virgo (constellation)",
"Constellations"
] |
59,604,285 | https://en.wikipedia.org/wiki/Dounce%20homogenizer | Invented by and named for Alexander Dounce
, a Dounce homogenizer or "Douncer", is a cylindrical glass tube, closed at one end, with two glass pestles of carefully specified outer diameters, intended for the gentle homogenization of eukaryotic cells (e.g. mammalian cells). Dounce homogenizers are still commonly used today to isolate cellular organelles.
The two Dounce homogenizer pestles (known as the "loose" or "A" and "tight" or "B" pestles), have a carefully specified outer diameter, relative to the inner diameter of the cylinder. The "A" (loose) pestle has a clearance from the cylinder wall of (~0.0025 - 0.0055 in.) while the "B" (tight) pestle has a clearance of (~0.0005 - 0.0025 in.). This allows for tissue and cells to be lysed by shear stress with minimal (if any) degree of heating, thereby leaving extracted organelles or heat-sensitive enzyme complexes largely intact.
Typically, a soft tissue (e.g. mammalian liver) is cut or broken into smaller pieces and placed into the glass cylinder, alongside a suitable volume of an appropriate lysis buffer. Homogenization is performed by a defined number of "passes" of the pestles, first with the loose pestle, then with the tight pestle, up and down the cylinder. Five to ten passes are typical. Dounce homogenizers are typically produced from borosilicate glass, but are still fragile, and should be used with care. Especially hard or tough tissues should be pre-homogenized before use in a dounce homogenizer.
Eukaryotic cells with tough cell walls, such as Saccharomyces cerevisiae, cannot be directly lysed with a dounce homogenizer, unless the cell wall is first broken down (e.g. with lyticase, or zymolyase in the case of S. cerevisiae).
References
Cell biology
Biochemistry
Laboratory glassware | Dounce homogenizer | [
"Chemistry",
"Biology"
] | 444 | [
"Biochemistry",
"Cell biology",
"nan"
] |
59,605,282 | https://en.wikipedia.org/wiki/Itarudivirus%20ARV1 | Acidianus rod-shaped virus 1 (ARV1), scientific name Itarudivurs ARV1, is an archaeal virus and the sole species in the genus Itarudivirus. Its only known host is Acidianus sp. Acii26.
References
Archaeal viruses
Ligamenvirales | Itarudivirus ARV1 | [
"Biology"
] | 68 | [
"Archaea",
"Viruses",
"Virus stubs",
"Archaeal viruses"
] |
59,605,439 | https://en.wikipedia.org/wiki/Icerudivirus%20SIRV1 | Sulfolobus islandicus rod-shaped virus 1 (SIRV1) is a virus in the order Ligamenvirales. Its only known host is the Archaean Sulfolobus islandicus. The species was first documented from a hot spring sample in Yellowstone National Park.
References
Archaeal viruses
Ligamenvirales | Icerudivirus SIRV1 | [
"Biology"
] | 69 | [
"Virus stubs",
"Viruses",
"Archaea",
"Archaeal viruses"
] |
59,605,831 | https://en.wikipedia.org/wiki/Pyramid%20wavefront%20sensor | A pyramid wavefront sensor is a type of a wavefront sensor. It measures the optical aberrations of an optical wavefront. This wavefront sensor uses a pyramidal prism with a large apex angle to split the beam into multiple parts at the geometric focus of a lens. A four-faceted prism, with its tip centered at the peak of the point spread function, will generate four identical pupil images in the absence of optical aberrations. In the presence of optical aberrations, the intensity distribution among the pupils will change. The local wavefront gradients can be obtained by recording the distribution of intensity in the pupil images. The wavefront aberrations can be evaluated from the estimated wavefront gradients.
It has potential applications in astronomy and ophthalmology.
Modulation
The prism is often modulated (mechanically moved in a circle/square) for averaging purposes and to make sure that the ray spends an equal fraction of the total time on every face of the pyramidal prism. This makes the wavefront sensor slightly inconvenient to use due to the need for mechanically moving parts – either the prism or the beam is modulated. Using a light diffusing plate, mechanically moving parts can be eliminated. Alternatively, it has been shown that the need for mechanically moving parts can be overcome in a digital pyramid wavefront sensor with the spatial light modulator.
References
Observational astronomy
Optical instruments
Sensors | Pyramid wavefront sensor | [
"Astronomy",
"Technology",
"Engineering"
] | 287 | [
"Sensors",
"Observational astronomy",
"Astronomical sub-disciplines",
"Measuring instruments"
] |
59,606,547 | https://en.wikipedia.org/wiki/Af%C5%9Fin-Elbistan%20power%20stations | The Afşin-Elbistan power stations are two coal-fired power stations in Turkey, a few kilometres apart in Afşin District in Kahramanmaraş Province. Both Afşin-Elbistan A, built in the 1980s, and the newer Afşin-Elbistan B burn lignite (brown coal) from the nearby Elbistan coalfield. As their mines are opencast and next to the power stations the coal is cheap. But as the existing units are the older subcritical type, and Turkish lignite is very low quality, they are not very efficient.
Both plants were built and first operated by the state-owned Electricity Generation Company, but Afşin-Elbistan A was sold to Çelikler Holding in 2018. Çelikler employs almost 1500 people, mostly local. Due a landslide at its mine stopping the supply of nearby coal, in late 2024 Afşin-Elbistan B stopped generating, but it may reopen in mid-2025.
Air pollution, such as sulfur dioxide, is trapped by surrounding mountains, and Greenpeace alleges that levels of particulates and nitrogen oxides in the atmosphere have exceeded legal limits. The Environment Ministry has not released flue gas measurements, and there is no recent public data from the nearest air quality monitor. Official health impact assessments are not done in Turkey, but the Right to Clean Air Platform estimates that the power station air pollution has killed over 17 thousand people. In December 2024 the environmental impact assessment allowing Çelikler Holding to build more coal power was approved. Human Rights Watch said that this conflicted with Turkey’s bid to host the 2026 climate change conference.
Afşin-Elbistan A
Afşin-Elbistan A is a 1355 MW lignite-fired power station, owned by Çelikler Holding.
Proposed expansion
The National Energy Plan published in 2023 forecast that 1.7 GW more local coal power would be connected to the grid by 2030, but did not say where.
In 2024, Çelikler was considering buying two cheap second-hand steam turbines from shut down American nuclear plants, but was unsure whether suitable steam boilers, which could cope with Turkish lignite could be found, as large electrostatic precipitators and flue-gas desulfurization (FGD) would be needed.
In December 2024 the environmental impact assessment (EIA), which began in 2022, of adding such 4th and 5th units totalling about 700 MW was approved. As of 2023, an official health impact assessment has not been done in Turkey, but opponents of the expansion estimate that the extra air pollution could lead to an additional 1900 premature deaths. This was estimated by using CALPUFF to model dispersion of NO2, SO2 and PM2.5. The deposition of mercury was also estimated. According to the EIA, 28 million tonnes of CO2 may be emitted per year, far more than the largest Turkish greenhouse gas emitter in 2022, which was ZETES power stations at 15 million tonnes.
History
Brought online from 1984 to 1987, Afşin-Elbistan A is one of the largest installed capacity coal-fired power stations in Turkey. At the time it was built solar and wind energy was extremely expensive and significant natural gas reserves had yet to be discovered in the country. Importing natural gas has cost the country a lot. Thus burning Afsin-Elbistan lignite limited the current account deficit.
The power station is estimated to emit over 8 million tonnes of per year, over 1% of Turkey's greenhouse gas emissions. It was depicted on the reverse of the 5000 lira banknotes of 1990–1994.
In 2005, the environment impact of rehabilitating the plant and also installing FGD was assessed. However FGD was not installed at that time and in January 2020, lower flue gas pollution limits came into force. The plant was shut down in January 2020 due to local air pollution, but reopened later in 2020. Delivery of FGD parts was delayed by the COVID-19 pandemic but the filters were installed in 2021.
In January 2019, locals complained that the plant had been restarted, causing ash pollution visible in the snow. Local MP, Sefer Aycan, said in parliament that he was concerned the plant would add to the industrial pollution of the Aksu and Ceyhan rivers.
In March 2019, Greenpeace projected the message "These chimneys are spitting poison" onto the plant, to publicise their earlier report claiming that, together with neighbouring Afşin-Elbistan B, the plants were responsible for 17,000 premature deaths. The area is a sulfur dioxide air pollution hotspot. According to energy analyst Haluk Direskeneli, writing in 2019, FGD was not installed and electrostatic precipitation was inadequate, and "it is futile to repair this power plant".
The plant was shut down in January 2020, as it did not meet the flue gas emission limits which came into force that month. Çelikler planned to have filters installed by June 2020. The plant reopened but complaints of air pollution continued, and in October 2021, it was said by opposition MP Ali Öztunç to be still operating without filters due to company lobbying. In 2020, the fuel oil system was replaced by gas and dry flue gas filters were completed; wet flue gas filters were completed in 2021.
In 2022, a study found levels of chromium and nickel in the soil exceeding regulations and the Climate Change Policy and Research Association alleged that the plant was operating illegally according to environmental laws. Little power was generated in 2023, due to damage caused by earthquakes.
Technology
The plant burns lignite, which is transported by conveyor belt from the nearby Kışlaköy coal mine. After burning, 2% of the lignite remains as slag and 18% as fly ash. A new landfill site was planned for both of these waste products in 2019. Use of modified fly ash in concrete has been suggested.
Afşin-Elbistan B
Afşin-Elbistan B is a 1440MW coal-fired power station in Afşin in Kahramanmaraş Province, state owned by the Electricity Generation Company (EUAŞ). The plant burns lignite from Kışlaköy coal mine (mostly transported by lorry) and sometimes from other mines.
History
Built between 2004 and 2005, Afşin-Elbistan B is the largest single coal-fired power station in Turkey and is estimated to emit almost 8 million tonnes per year, over 1% of Turkey's greenhouse gas emissions. Opponents said in 2020 that ash retention filters were disabled on the pretext that they are expensive to clean. An environmental impact report for proposed ash and slag storage was approved in 2020. By 2021, unit 3 had been converted to gas. The plant stopped running in late September 2024, and due to lack of coal caused by a landslide at the nearby Kışlaköy coal mine. It was predicted not to run again until sometime in 2025.
Cancelled power stations
Afşin-Elbistan C
Afşin-Elbistan C was a planned 1800-MW coal-fired power station, which was proposed to be funded by the Turkey Wealth Fund and built by state-owned mining company, Maden Holding. According to the EIA, the plant would have burned 23 million tonnes of lignite annually, and emitted over 61 million tonnes of each year for 35 years. In 2021, Turkey targeted net zero carbon emissions by 2053, and in 2022, the C power station was cancelled.
Like some other power stations in Turkey, the proposed three units of 600 MW for Afşin C were planned to be state-owned. Estimated to cost lira ( USD), and had a planned capacity of 11 TWh per year (about 3% of Turkey's annual power generation).
The site, on the border in Afşin district, is near the two existing Afşin-Elbistan power stations. In 2019, compulsory purchase of the land was authorised by President Erdoğan. Hurman Creek would have been diverted to allow more access to Elbistan coalfield, as well as supplying the plant's cooling water. Earlier in 2021, negotiations with Chinese companies continued, but later that year, China stopped funding overseas coal power.
The station was planned to run almost 7000 hours per year to generate 11,380 GWh. By using a supercritical boiler, the plant would have been more efficient and emitted less local air pollution than all other large (over 400 MW) local lignite-fuelled power stations in Turkey, as they use subcritical boilers. According to the Turkey Wealth Fund, the plant would have been environmentally friendly, using the latest emission control technologies. Cooling water would have been supplied from Hurman Creek via the Karakuz Dam, (which was completed in 2024). According to Climate Action Network Europe, the plant would have increased the risk of drought in the area.
Afşin-Elbistan D and E
The coalfield also has D and E sectors but, although D and E power stations were planned in the early 21st century, they are not in use.
Coal
Mine
Disease and deaths
Article 56 of the constitution says that “Everyone has the right to live in a healthy and balanced environment. It is the duty of the State and citizens to improve the natural environment, to protect the environmental health and to prevent environmental pollution.” In 2024, Human Rights Watch alleged that the existing power stations and proposed expansion contravene the constitution and violate the human rights of nearby residents by damaging their health.
According to the Right to Clean Air Platform Turkey the power stations have caused over 17 thousand premature deaths as of 2024. The Health and Environment Alliance estimate almost one hundred thousand cases of bronchitis have been caused, mostly in children. There is an air quality monitoring station in Elbistan, which is 22 km away from the power stations, and its data is public: however data from air quality monitoring 3 km from the power stations is not public.
The Health and Environment Alliance estimate that phasing out coal by 2030, instead of when the A and B power plant licences end in 2038 and 2052 respectively, would prevent over 2000 premature deaths. There is a pollutant release and transfer register, but as of 2025, no years are publicly searchable because it is not yet technically complete, and it is not known what pollution sources will be granted exemptions. According to Greenpeace, many people in nearby villages, such as Çoğalhan and Altınelma, complain of asthma. Çoğulhan has 3 times the SO2 level of Elbistan. Climate Trace has estimated 2023 local air pollution from the A plant at: 120t PM, 9.35Kt , and 10.52Kt .
Economics
According to Çelikler, the A plant and mine employed 1450 people, mostly local, in 2024.
The C plant was planned to operate for 35 years and was proposed to be partially funded by the Turkey Wealth Fund (TWF), the country's sovereign wealth fund, a major partner. This is in accordance with the energy policy of Turkey, which prioritises local sources of energy to reduce coal and natural gas imports, partly in order to maintain energy security. Verus Partners advised on finance, but despite low production costs, the private sector was not interested, as the coal is low-quality. The TWF claimed the plant would have an economic life of 35 years, create "serious employment", and Vice President Fuat Oktay said in 2020 that it would reduce the current account deficit. According to Greenpeace, local farmers say ash has reduced their crop yields. In 2024, Greenpeace argued that the proposed 36b lira investment in new coal power would be better spent on solar power and energy storage.
Pollution
After a long-running legal case, some data from the continuous emissions monitoring system requested by Greenpeace was released.
Greenhouse gas emissions
The Afşin-Elbistan C EIA estimated emissions would be more than 60 million tonnes of per year: and was accepted by the government. For comparison, total annual greenhouse gas emissions by Turkey are less than 575 million tonnes; thus about a tenth of greenhouse gas emissions by Turkey would have been from the planned power station. Space-based measurements of carbon dioxide means the public will know the level of emissions almost in real time.
Opposition
Environmentalists claimed the country already had too much electricity generating capacity. Environmental and public health groups criticised the proposed C plant EIA for describing coal as clean energy and, in February 2020, thousands of people filed petitions against its approval. It was approved by the Ministry of Environment and Urbanisation in March 2020. In 2021, an expert report commissioned by the Maraş Regional Administrative Court said that the EIA positive decision given to Afşin-Elbistan C was faulty as it failed to accurately assess the project's environmental pollution and impact on agricultural activities, water basins and human health. Environmental group TEMA Foundation said, as Turkey had recently ratified the Paris Agreement to limit climate change, the plans to build the C plant should be immediately abandoned. In 2021, the C plant was cancelled.
In 2024, the mayors of Elbistan and nearby Nurhak opposed the proposed expansion of the A plant.
Public opinion
According to a 2020 survey from nearby Kahramanmaraş Sütçüimam University, most locals say they have chronic illness, and almost all believe that environmental protection measures taken by power plant managers are insufficient. Opponents of the plants say that: "a significant portion of the people living in Afşin Elbistan are struggling with cancer or respiratory tract diseases."
Notes
References
See also
Coal power in Turkey
External links
Afşin-Elbistan power stations on Global Energy Monitor
Report on health effects (in Turkish) by the Right to Clean Air Platform Turkey
B plant tenders (in Turkish)
Report on health effects(in Turkish) by the Right to Clean Air Platform Turkey
Greenhouse gas emissions
Coal-fired power stations in Turkey | Afşin-Elbistan power stations | [
"Chemistry"
] | 2,905 | [
"Greenhouse gases",
"Greenhouse gas emissions"
] |
59,607,750 | https://en.wikipedia.org/wiki/Neem-coated%20urea | Neem-Coated Urea is a fertilizer and an agriculture scheme supported by the Government of India to boost the growth of wheat and paddy, and curb the black market and hoarding of urea. Urea that is coated with neem tree seed oil is called neem-coated urea. In January 2015, the urea manufacturers were mandated by the government to increase their production from 35 percent to 75 percent of their subsidised amounts of neem-coated urea.
In her 2019 budget presentation, finance minister Nirmala Sitharaman spoke about increased promotion of neem coated urea among farmers which will help to reduce the cost of cultivation.
Benefits of Neem Coated Urea include; Increase of Crop-specific yields by 15-30% on average along with higher levels of soil fertility.
The patent for Neem Coated Urea is owned by Aditya Birla Nuvo Ltd and its assignees are the Aditya Birla Nuvo Ltd. & Aditya Birla Science and Technology co. ltd. under the guidance of Dr. Prashant Puri, who is the primary innovator in this area.
References
Fertilizers
Agriculture in India | Neem-coated urea | [
"Chemistry"
] | 246 | [
"Fertilizers",
"Soil chemistry"
] |
59,608,076 | https://en.wikipedia.org/wiki/Spektr-M | Spektr-M (Russian: Спектр-M) is a proposed Russian scientific satellite with a sub-millimeter to far infrared space telescope. It is designed to be a successor to the Herschel Space Observatory, covering similar wave bands, and to look into chemical evolution in the universe, black hole horizon radiation, and dark energy investigation. Spacecraft design documentation and prototyping is currently underway and expected to continue until 2023. Due to budget cuts in 2019, launch is not expected until 2030.
Overview
The purpose of this mission is to study the universe in millimeter to far infra-red wavelengths. The Herschel mission did a similar job with a smaller dish of , and this is a follow-up mission. The instruments are to be cooled with liquid helium to 4.5K for part of the mission, but sun shields will allow it to continue in a degraded mode once the coolant evaporates.
It will be placed in a halo orbit around the Sun–Earth Lagrangian point.
References
External links
Millimetron site
Popular Mechanics (RU)
Space telescopes
2030s in spaceflight
2020s in Russia
Infrared telescopes
Satellites of Russia
Roscosmos
Proposed spacecraft | Spektr-M | [
"Astronomy"
] | 247 | [
"Space telescopes",
"Astronomy stubs",
"Spacecraft stubs"
] |
59,608,767 | https://en.wikipedia.org/wiki/HD%2021749 | HD 21749 is an orange main-sequence star in the constellation Reticulum. It has an apparent visual magnitude of 8.143, which means it is too dim to be seen with the naked eye. From parallax measurements by the Gaia spacecraft, it is located from Earth.
In 2019, it was discovered that the star has two exoplanets: a possibly rocky, hot sub-Neptune-sized exoplanet named HD 21749 b; and an Earth-sized exoplanet named HD 21749 c. These exoplanets were discovered by the TESS spacecraft.
Stellar characteristics
HD 21749 is a K-type main sequence star (orange dwarf) with a spectral type of K4.5V, indicating it is smaller and cooler than the Sun. It is estimated to have a mass of , a radius of , and a luminosity of . Its effective temperature is 4,640 K, which gives the star an orange color typical of K-type stars. Its metallicity—the proportion of elements other than hydrogen and helium—is approximately equal to the Sun's.
This star is moderately active, as shown by its spectral activity indicators and photometric data. These measurements indicate a rotation period of around 30 to 40 days, with a most likely value of 34 days. Stellar activity also creates radial velocity variations, which complicates the measurement of the mass of the planets in the system.
A companion to HD 21749 is listed in double star catalogues, a 9th-magnitude star separated by in 2015, although decreasing rapidly due to the high proper motion of the primary. The companion is much more distant than the primary and the two are unrelated except being coincidentally in the same line of sight.
Planetary system
In January 2019, the discovery of an exoplanet around HD 21749 was published. The planet was identified from a single transit event detected by the TESS spacecraft, using data from the first two observation sectors of the mission. Since a single transit is insufficient to determine the orbit of a planet, astronomers used archival radial velocity data from the HARPS spectrograph to detect the planet's signal, which allowed the determination of its orbital period and mass. In April 2019, with two additional months of data from the TESS spacecraft, the orbital period of the planet was confirmed with the observation of new transits, and a second planet was discovered.
HD 21749 c
The inner planet, HD 21749 c (the second in order of discovery), is orbiting the star at a distance of 0.08 AU with a period of just 7.8 days. A terrestrial planet, it has a radius of and was the first Earth-sized planet found by TESS. Its mass is too low to be calculated with current radial velocity data, with an upper limit of ; a probabilistic model estimates it is most likely between 1 and .
HD 21749 b
The outer planet, HD 21749 b, orbits the star at a distance of 0.21 AU with a period of 35.6 days. With a mass of and a radius of , it is similar to Neptune but much denser. Its density of 4.7 g/cm³ suggests it is composed of a substantial rocky core, with a radius of approximately , plus a relatively thick gaseous layer.
References
External links
Planetary transit variables
Planetary systems with two confirmed planets
Reticulum
K-type main-sequence stars
021749
0143
016069
186
Durchmusterung objects | HD 21749 | [
"Astronomy"
] | 709 | [
"Reticulum",
"Constellations"
] |
59,609,094 | https://en.wikipedia.org/wiki/Lewis%27%20law | Lewis' law gives a relationship between the size and the shape of epithelial cells. It states that the average apical area of an epithelial cell is linearly related to its neighbor number . It is a phenomenological law that was first described in the cucumber epidermis by the morphologist Frederic Thomas Lewis in 1928. The simplest version of Lewis' law can be expressed as , which reads: The average apical area of a cell with neighbors (divided by the average apical area of all cells) is proportional to its shape. While neighbor number distributions change throughout organogenesis, the average neighbor number of epithelial cells is , which can be traced back to Euler's formula for polygons.
Discovery
Frederic Thomas Lewis noticed that epidermal cells display a patterning similar to froths, which led him to quantify and analyze the sizes and shapes of epidermal cells.
Confirmation and mechanism
A variety of empirical studies in different epithelial tissues have confirmed Lewis' law.
It has been suggested that the emergence of Lewis' law on the apical surface of epithelia is a result of the concurrence of
the tendency of cells to minimize intercellular contact surface energy, and
the distribution of apical cell areas (as a result of cellular processes such as cell division).
According to this theory, the observed tissue-specific polygon distributions and Lewis' law arise as a compromise in order to maintain tissue integrity.
Importance
In order to understand morphogenetic events, i.e. the growth and shaping of tissues and organs, it is necessary to analyze the packing of cells into tissues. In that context, an analysis of patterning processes can help to identify the underlying mechanisms that drive morphogenesis.
References
Epithelium
Biological theorems | Lewis' law | [
"Biology"
] | 366 | [
"Biological theorems"
] |
59,609,098 | https://en.wikipedia.org/wiki/Optical%20baffle | An optical baffle is an opto-mechanical construction designed to block light from a source shining into the front of an optical system and reaching the image as unwanted light.
Principles
Optical systems which have stringent requirements on stray light levels often need optical baffles. There are many designs, depending on the desired goals. Generic optical baffle designs and their advantages for stray light control can be classified as reflective, absorbing or refractive; reimaging and nonreimaging systems.
References
Optical devices | Optical baffle | [
"Materials_science",
"Engineering"
] | 102 | [
"Glass engineering and science",
"Optical devices"
] |
59,609,137 | https://en.wikipedia.org/wiki/K2-288Bb | K2-288Bb (previously designated EPIC 210693462 b) is a super-Earth or mini-Neptune exoplanet orbiting in the habitable zone of K2-288B, a low-mass M-dwarf star in a binary star system in the constellation of Taurus about 226 light-years from Earth. It was discovered by citizen scientists while analysing data from the Kepler space telescope's K2 mission, and was announced on 7 January 2019. K2-288 is the third transiting planet system identified by the Exoplanet Explorers program, after the six planets of K2-138 and the three planets of K2-233.
K2-288Bb is likely to be in the habitable zone of its host star, and thus may be capable of supporting life, though the planet's composition is unknown.
Discovery
K2-288 was observed by the Kepler space telescope during Campaign 4 of its extended K2 "Second Light" mission, lasting from April through September 2015. A group of astronomers looked through this data to try and find transiting exoplanets. However, because of Kepler's decreased stability after the failure of two reaction wheels, the start of each campaign had extreme systematic errors, and these few days of data were discarded by the team. For K2-288, they only found two transits in the remaining data, not enough to merit follow-up studies. As a result, this system was put aside for more convincing candidates.
After the first analysis, the same team used better methods to model the systematic errors caused by K2 and re-processed all the Campaign 4 data they had. However, instead of looking through it all again by eye, they decided to upload it to the new Zooniverse project Exoplanet Explorers in April 2017. Among other systems, like K2-138, citizen scientists also spotted three transits of the red dwarf star EPIC 210693462. Several volunteers started a lengthy discussion thread about the system, concluding that, with the current transit and stellar parameters, the planet candidate was very similar in both size and temperature to Earth. This caught the attention of the original team of astronomers and another at NASA Goddard who independently found the three transits at the same time, and follow-up observations were started.
The group, led by Adina Feinstein, started by obtaining spectra of the star using the Keck Observatory in Hawaii, where they noticed that there was a secondary companion star. This meant there was a possibility that the second star was creating the transit signal, and it wasn't a real planet. However, the team concluded that it was far more likely to be an exoplanet and not a false positive. They used data from Kepler, as well as a transit observed by the Spitzer Space Telescope, to determine which star the planet orbited. Observations and modelling suggested the transit data was most compatible with the planet transiting the smaller, secondary star. The team was then able to calculate the radius, orbit, and temperature of the planet, and they announced their results at the 233rd American Astronomical Society meeting in Seattle on January 7, 2019.
Characteristics
Mass, radius, and temperature
K2-288Bb is unusual for having a radius not commonly seen among most exoplanets. At 1.90 , it falls within the so-called Fulton gap between 1.5 and 2.0 . This is the range of sizes where rocky super-Earths start to accumulate thick volatile layers and turn into mini-Neptunes. Planets in the middle of this gap are uncommon, and as such, not much is known about them. K2-288Bb could either be a low-density mini-Neptune like GJ 9827 d, or a large rocky super-Earth like LHS 1140 b. Its mass is currently unknown and would require additional studies using the Radial velocity method to be determined. Based on its size, K2-288Bb is probably still undergoing atmospheric evolution and/or erosion. The planet is also orbiting in or near the habitable zone of K2-288B, where temperatures are just right for a planet to host liquid water with the right atmosphere. K2-288 Bb has an equilibrium temperature of (lower than Earth's ) and receives less sunlight than Earth.
Orbit and rotation
K2-288Bb has a close orbit around the second, smaller star of the binary system. It orbits every 31.393 days at a distance of about 0.164 AU. For comparison, the Earth's Solar System's innermost planet, Mercury, orbits every 88 days at 0.38 AU. However, due to the small size of the host star, K2-288Bb is well within the habitable zone. In the unlikely possibility that the planet orbits the primary, it would have a semi-major axis of 0.231 AU and still reside in the habitable zone. K2-288Bb is probably tidally locked regardless of which star it orbits; one side of the planet would permanently face the host, while the other side would be always facing away.
Host stars
K2-288Bb is within a binary system of two red dwarfs. The primary, K2-288A, is 52% the mass and 45% the radius of the Sun, while the secondary, K2-288B, is 33% the mass and 32% the radius. They are both much cooler and dimmer than the Sun, with temperatures of 3584 K and 3341 K, and are 0.03236 and 0.01175 times as luminous as the Sun, which has a temperature of 5772 K. Both stars are also rather metal-poor, with metallicities of -0.29 dex [Fe/H] for the primary, and -0.21 dex [Fe/H] for the secondary. In comparison, the Sun has a metallicity of 0.00 dex [Fe/H]. K2-288A and K2-288B orbit each other at a distance of about 55 AU, around six times the distance from Saturn to the Sun.
Potential habitability
It is unknown if K2-288Bb is capable of supporting life. On one hand, it is likely well within the habitable zone of its star, with a temperate equilibrium temperature of about 226 K. However, because of its radius within the Fulton gap, there is significant uncertainty in its composition. K2-288Bb could be a potentially habitable rocky or water-rich world, but it might also be a hostile gas planet.
See also
Kepler-296f, another temperate planet in a binary system with a radius inside the Fulton gap
K2-138
List of exoplanet extremes
List of potentially habitable exoplanets
References
External links
Taurus Constellation at Constellation Guide
The Deep Photographic Guide to the Constellations: Taurus
Exoplanets discovered in 2019
Terrestrial planets
Transiting exoplanets
Taurus (constellation)
Exoplanets discovered by K2
Super-Earths in the habitable zone | K2-288Bb | [
"Astronomy"
] | 1,448 | [
"Taurus (constellation)",
"Constellations"
] |
59,609,345 | https://en.wikipedia.org/wiki/Hearing%20protection%20fit-testing | Hearing protector fit-testing is a method that measures the degree of noise reduction obtained from an individual wearing a particular hearing protection device (HPD) - for example, a noise canceling earplug or earmuff. Fit testing is necessary due to the fact that noise attenuation varies across individuals. It is important to note that attenuation can sometimes score as zero due to anatomical differences and inadequate training, as to the proper wear and use. Labeled HPD attenuation values (for example, the Noise Reduction Rating, or NRR) are average values that cannot predict noise attenuation for an individual; in addition, they are based on laboratory measurements which may overestimate the noise reduction obtained in the real world.
Hearing protection devices such as earplugs or earmuffs must be worn correctly for the wearer to be protected from noise. Correct use of hearing protection includes:
Choosing the most appropriate hearing protection device, both with appropriate level of attenuation and appropriate fit for the individual. Ideally, the device should limit the sound intensity that reaches the ear to levels below 85 dBA. If the attenuation does not limit the noise levels to that level, other alternatives should be sought. If the attenuation is greater than that, it can also interfere with the HPD use by making it difficult to hear important sounds.
Wearing or inserting the hearing protection device correctly so it seals the wearer's ear canal, using the "roll-pull-hold" method for foam earplugs, and ensuring earmuffs create an unbroken seal around each ear.
Fit-testing hearing protection can facilitate an appropriate choice of hearing protection, and allow for the professional administering the fit-test to train users on proper techniques for wear.
Requirements and Recommendations for HPD Fit Testing
The Occupational Safety and Health Administration, National Hearing Conservation Association, and National Institute for Occupational Safety and Health recommend it for all workers used HPD as a best practice, and describes existing testing methods and how to incorporate them in hearing conservation programs.
Effective March 31, 2023, the Alberta Government added a requirement that employers fit test each employee who wears HPDs. A trend towards recommending HPD fit-testing as a best practice is emerging in the European Union and the USA.
Fit-testing methods
Fit testing is typically carried out using one of the available fit-testing hardware and software systems (also known as field attenuation estimation system (FAES). Although all fit-testing systems measure the amount of sound reduction provided by hearing protection devices, different systems use different approaches to making this measurement.
The different methods used to measure the attenuation provided by HPDs are as follows:
Real-ear attenuation at threshold (REAT)
REAT is the most commonly used type of fit-testing technology used in commercial systems. REAT systems are modeled on the "gold-standard" approach to measuring hearing protector attenuation as defined in acoustic standards such as ANSI/ASA S12.6 and the ISO 4869-1. This approach measures the difference in auditory (hearing) thresholds without hearing protection (unoccluded) and with hearing protection (occluded). Differences in occluded and unoccluded thresholds across one or more test frequencies are used to calculate the noise reduction. REAT systems rely on the subjective response of the person being tested to determine auditory thresholds much like a hearing test where the subject indicates when sound is heard at various frequencies.
According to the acoustic standards, REAT testing of hearing protection devices must be tested in an acoustic chamber with a diffuse sound field. Because such chambers are not mobile, portable fit-testing systems employing sound-isolating headphones have been developed to test earplugs. For noncritical screening, REAT can be performed using a web browser and simple audio devices.
Loudness balance
This method first has the subject listen to tones with headphones and "match" loudness between both ears until tones sound equally loud on both sides. Then an earplug is placed in one ear while the baseline procedure is repeated to match loudness in both ears. The increase in loudness required to balance represents the attenuation achieved in that ear. The second earplug is then placed in the other ear and the procedure is repeated a third time. The required increase in loudness this time represents the noise reduction achieved in the second ear. The loudness balance fit-testing approach provides individual personal attenuation ratings for each ear.
Microphone-in-real-ear (MIRE)
Also referred to as F-MIRE (field microphone in real ear). This method measures attenuation by placing a small microphone inside the ear canal while hearing protection is worn. Sound pressure levels (SPL) are measured inside and outside of the ear simultaneously and used to calculate a PAR.
Fit test results
The effectiveness is typically measured as a personal attenuation rating (PAR) which is subtracted from the known noise exposure to estimate the total noise exposure a single person has when wearing the tested hearing protection device (HPD).
The outcome measure generated by hearing protector fit-test systems varies from a simple pass/fail to a quantitative personal attenuation rating (PAR). and can be interpreted differently to determine the effectiveness of hearing protection or calculate total noise exposure.
Personal attenuation rating (PAR)
Similar to a noise reduction rating (NRR) required on hearing protection devices in the United States, a personal attenuation rating (PAR) is obtained from an attenuation measurement at one or more than one frequency. The effectiveness is typically measured as a personal attenuation rating (PAR) which is subtracted from the known noise exposure to estimate the total noise exposure a single person has when wearing the tested hearing protection device (HPD). However, the PAR is regarded as more accurate than the NRR because it is calculated per individual and per hearing protection device, while NRR is a generalized estimate of potential sound reduction based on the protection provided to a small population of people. Therefore, PAR gives the evaluator an estimate of the total noise exposure an individual is receiving when wearing hearing protection.
PAR is subtracted from the known noise exposure to estimate the total protected noise exposure a single person has when wearing the tested HPD. The method for estimating protected noise exposure based on the measured PAR may vary slightly across fit-test systems, so it is important to understand to use the PAR generated by a given fit test system
Use of Fit-testing as a training tool
Evidence shows that including fit-testing as a part of employee training for correct hearing protection device use increases the user's ability to properly fit the device, and that this ability is often retained on follow-up. Fit testing provides the individual with immediate feedback regarding the noise reduction achieved, which helps them understand how the device should feel when it is properly fit. Investments in fit testing and training have been shown to be effective at reducing the rates of standard threshold shifts in industry.
A systematic review published in 2024 investigated the effectiveness of hearing protection fit-testing systems and as well as any training occurring alongside the use of these systems in improving the amount of attenuation from noise these workers received. This review included three different studies, which together totaled evaluations on 756 participants. The studies evaluated the impacts of either simple or extensive instructions provided to workers for inserting and fitting earplugs (foam or pre-molded). Extensive training included personalized instruction, while simple training lacked this one-on-instruction. Fit testing with extensive instructions was found to enhance workers’ protection against noise following the test and training sessions, while training with only simple instructions did not significantly improve personal attenuation ratings over the absence of instructions. Thus, fit testing system effectiveness may vary depending on the type of training methods employed in addition to the type of HPD used during fit testing.
See also
Noise health effects
Noise-induced hearing loss
Hearing conservation programs
Hearing protection device
Earplug
Earmuffs
Safe-in-Sound Award
Safe listening
References
External links
OSHA's Letter of interpretation on hearing protection fit-testing
NIOSH, Provide Hearing Protection
DOD, 2024 policy on hearing protection fit-testing US Department of Defense
Video: The importance of hearing protection fit testing, Hearing Center of Excellence
Occupational safety and health
Hearing loss
Audiology
Acoustics
Hearing
Protective gear | Hearing protection fit-testing | [
"Physics"
] | 1,707 | [
"Classical mechanics",
"Acoustics"
] |
59,609,578 | https://en.wikipedia.org/wiki/Lyophyllum%20littoralis | Lyophyllum littoralis, is a grey edible mushroom of the genus Lyophyllum. It is closely related to Lyophyllum decastes. It is hot climate fungus species common in Mediterranean coniferous woodlands. Often growing in clusters.
Taxonomy
Lyophyllum littoralis was first described as a separate species in 1998 by Italian mycologist Marco Contu.
Description
The smooth cap is 5–15 cm (2–6 in) wide mottled grey to brownish grey colour, with darker splotches tending to be around the edge. Often covered in a whitish powder. Cap shape in younger specimen tends to be round and becomes convoluted with age, with the cap edge pointing downwards.
The stipe is 1.5–4 cm (0.6–1.6 in) high and up to 0.4-1.5 cm wide and has no ring nor volva. Often hollow the stipe ranges from white at the top to grey at the bottom with older specimen being grey
The gills are white tending to pale yellow-grey in older specimen. the gills densely packed, can be free (unattached to the stipe) or slightly sliding to the stipe.
The flesh is thin and rubbery, and does not break easily, especially the stipe. Older specimen (especially after sporulation) exude a distinct coconut scent. Younger specimen have no discernible scent or taste prior to cooking.
White spore in bulk. Spores 4.5-5.5 (6) × 4.5-5.5 μm, globular, smooth, cyanophile, often with central guttula. Tetrasporic, trivial basidia. GAF present in all tissues.
Distribution and habitat
Lyophyllum littoralis is found in Mediterranean woodlands, where fruiting bodies appear under conifers, particularly pine, from November to January. They generally appear in clumps connected to the same base, but can also appear individually.
Edibility
With a taste reminiscent of fried chicken and texture that retains its firmness after frying, the species is a good edible.
References
External links
Lyophyllum littoralis - Gruppo Micologico «G. Bresadola»
Lyophyllaceae
Fungi of Europe
Fungi described in 1998
Edible fungi
Fungus species | Lyophyllum littoralis | [
"Biology"
] | 481 | [
"Fungi",
"Fungus species"
] |
59,610,161 | https://en.wikipedia.org/wiki/Concreteness%20training | Concreteness training (CNT) is the repeated practice of cognitive skills to create habitual behaviors in order to help reduce anxiety and depressive symptoms for those suffering from the disorder of depression. People suffering from depression have a tendency towards unhelpful abstract thinking and negative thoughts, such as viewing a single mistake as evidence that they are useless at everything. As such, CNT involves switching cognitive focus from negative thoughts to positive thoughts so as to cut down on rumination—focused attention on the symptoms of one's distress—and self-criticism, which can cause feelings of inadequacy and raise anxiety.
This technique was developed at the University of Exeter, located in Exeter, England, by Professor Edward Watkins and his team of researchers after they conducted a study to see if the CNT approach could reduce symptoms of depression and anxiety. In the 2009 study, twenty-one men and thirty-nine women were randomly assigned to one of three groups. The first group received CNT, the second group received bogus concreteness training (BGT), and the third group was a wait-list (WL) control condition that received no treatment. The concreteness training involved practicing thinking about the specific details of recent mild negative events: how the event happened, where it happened, who was there, what they did. The goal was to try to get a mental picture of the event, its circumstances, and then focus on the sequence of how it happened. Participants received the specific treatment every day for a week based on their assigned group. At the end of the week, participants were again assessed for depression levels and symptoms. Results indicated that CNT showed a trend toward a greater decrease in depressive symptoms than BGT or WL. Accordingly, Professor Watkins noted: “This is the first demonstration that just targeting thinking style can be an effective means of tackling depression. Concreteness training can be delivered with minimal face-to-face contact with a therapist and training could be accessed online, through CDs or through smartphone apps. This has the advantage of making it a relatively cheap form of treatment.”
However, in a study published by Springer Nature in 2013, it was concluded that the effectiveness of CNT may be limited, claiming that while concreteness of thinking increased, results did not support that CNT was effective "as a standalone treatment for depression". In addition, contrary to previous findings, the study also did not find a significant effect on rumination. The potential reasoning behind this lack of effect was "because the sample did not exhibit a significant decrease in depression". Yet, CNT has been proven to be effective when delivered in a specific manner, like therapeutic context, with the rationale that the participant knows he or she is being treated for depressive symptoms by a credible authority. Moreover, results have also demonstrated that CNT is a valid technique in the reduction of self-criticism, especially where the use of self-relevant events (autobiographical materials) has been prevalent.
See also
Cognitive psychology
Management of depression
References
Cognitive psychology | Concreteness training | [
"Biology"
] | 614 | [
"Behavioural sciences",
"Behavior",
"Cognitive psychology"
] |
47,716,123 | https://en.wikipedia.org/wiki/Penicillium%20sterculiniicola | Penicillium sterculiniicola is a species of fungus in the genus Penicillium which was isolated from spawn run compost in the United States.
References
sterculiniicola
Fungi described in 2014
Fungus species | Penicillium sterculiniicola | [
"Biology"
] | 48 | [
"Fungi",
"Fungus species"
] |
47,717,506 | https://en.wikipedia.org/wiki/GeoEcoMar | The National Institute for Research and Development of Marine Geology and Geoecology – GeoEcoMar () is a Romanian institute of geology and geo-ecology founded in 1993. It was initially named Romanian Centre for Marine Geology and Geo-ecology. Its administrative and scientific headquarters is in the capital of Romania, Bucharest; but the operational center, with the research vessels and marine infrastructure, is in Constanța, an important harbor on the Black Sea. The first director of the institute was the academician Nicolae Panin, now retired and a personal adviser of the current director, Gheorghe Oaie.
Programs and partners
GeoEcoMar is involved in European research programs of hydrological river-delta-sea macro-systems. It has fathomed the study of coastal erosion and its correction and participates in European programs to monitor potential hazards in the Black Sea. It explores the environmental effects of a dramatic decline due to the sediments collected by the upstream dams. Also, the Institute is involved in carbon dioxide capture and storage.
Since 1996, GeoEcoMar has been formally authorized to develop impact studies and environmental evaluations in Romania. Since 2006 it has been certified ISO 9001 for research conducted in geology, geophysics and geo-ecology, and by Lloyd's Register Quality Assurance (Romania) in accordance with ISO 9001: 2008 and ISO 9001: 2008. The Institute obtained the European status of excellence (Euro-EcoGeoCentre Romania).
GeoEcoMar is, alongside similar institutes from Italy, France, UK, Greece, Spain, Ireland, the Netherlands, Germany and Portugal, a member of the European Multidisciplinary Seafloor and water column Observatory (EMSO), a network of various institutes and companies monitoring the open ocean or shallow waters in order to prevent hazards, tsunami or earthquake effects. It has initiated Évolution du littoral danubien: vulnérabilité et prévention project which is to collect seismic data from the mouth of the river Danube, to study the morpho-sedimentary structure of the river-sea system.
Fleet
The Institute’s investigations are undertaken with the help of the largest research vessel in the Black Sea: Mare Nigrum, an interdisciplinary research vessel which is 82 m long and has a displacement capacity of 3200 tonnes; and also Istros, which has a length of 32m and a displacement of 125 tonnes; and Halmyris, a laboratory boat bridge of 32 meters long and a displacement capacity of 90 tonnes.
References
External links
GeoEcoMar home page (in Romanian)
GeoEcoMar home page (in English)
Romania
Black Sea
Research institutes in Romania
Danube Delta
Hydrology organizations
1993 establishments in Romania
Organizations established in 1993 | GeoEcoMar | [
"Environmental_science"
] | 552 | [
"Hydrology",
"Hydrology organizations"
] |
47,719,289 | https://en.wikipedia.org/wiki/Acylurea | Acylureas (also called N-acylureas or ureides) are a class of chemical compounds formally derived from the acylation of urea.
Uses
Insecticides
A subclass of acylureas known as benzoylureas are insecticides. They act as insect growth regulators by inhibiting the synthesis of chitin resulting in weakened cuticles and preventing molting. Members of this class include diflubenzuron, flufenoxuron, hexaflumuron, lufenuron, and teflubenzuron.
Anticonvulsants and sedatives
The acylurea functional group is also found in some pharmaceutical drugs such as the anticonvulsants phenacemide, pheneturide, chlorphenacemide, and acetylpheneturide (which are phenylureides), and the sedatives acecarbromal, bromisoval, and carbromal (which are bromoureides). Others include apronal (apronalide), capuride, and ectylurea. Barbiturates (a class of cyclic ureas) are structurally and mechanistically related to them. The phenylureides are also closely related to the hydantoins, such as phenytoin, and may be considered ring-opened analogues of them.
Related
Diureides
A diureide is a complex nitrogenous substance regarded as containing two molecules of urea or their radicals, e.g. uric acid or allantoin.
Hydantoins
Hydantoin, or glycolylurea, can be considered the cyclic form of acylurea.
References
Ureas
Functional groups | Acylurea | [
"Chemistry"
] | 368 | [
"Organic compounds",
"Functional groups",
"Ureas"
] |
47,719,483 | https://en.wikipedia.org/wiki/NGC%20526 | NGC 526 is a pair of interacting lenticular galaxies in the constellation of Sculptor. Both the constituents are classified as S0 lenticular galaxies. This pair was first discovered by John Herschel on September 1, 1834. Dreyer, the compiler of the catalogue described the galaxy as "faint, small, a little extended, the preceding of 2", the other object being NGC 527.
See also
List of NGC objects (1–1000)
References
External links
SEDS
Lenticular galaxies
Sculptor (constellation)
0526
05120
Discoveries by John Herschel
Astronomical objects discovered in 1834 | NGC 526 | [
"Astronomy"
] | 119 | [
"Constellations",
"Sculptor (constellation)"
] |
47,719,639 | https://en.wikipedia.org/wiki/NGC%20201 | NGC 201 is a spiral galaxy in the constellation of Cetus. It is one of the group members of HCG 7, with the other group members NGC 192, NGC 196, and NGC 197. It was discovered on December 28, 1790 by William Herschel.
One supernova has been observed in NGC 201: SN 2019yc (type IIb, mag. 16.7) was discovered by Kōichi Itagaki on 22 January 2019.
See also
List of NGC objects (1–1000)
Image gallery
References
External links
SEDS
0201
0419
+00-02-115
002388
Spiral galaxies
Astronomical objects discovered in 1790
Discoveries by William Herschel
Cetus | NGC 201 | [
"Astronomy"
] | 140 | [
"Cetus",
"Constellations"
] |
47,719,656 | https://en.wikipedia.org/wiki/Water%20usage%20effectiveness | Water Usage Effectiveness (WUE) is a sustainability metric created by The Green Grid in 2011 to attempt to measure the amount of water used by datacenters to cool their IT assets.
To calculate simple WUE, a data center manager divides the annual site water usage in liters by the IT equipment energy usage in kilowatt hours (Kwh). Water usage includes water used for cooling, regulating humidity and producing electricity on-site. More complex WUE calculations are available from The Green Grid website.
See also
Data center infrastructure efficiency
Performance per watt
Green power usage effectiveness
Green computing
IT energy management
PUE
References
Benchmarks (computing)
Water conservation | Water usage effectiveness | [
"Technology"
] | 132 | [
"Benchmarks (computing)",
"Computing comparisons",
"Computer performance"
] |
47,720,641 | https://en.wikipedia.org/wiki/Associated%20General%20Contractors%20of%20America | The Associated General Contractors of America (AGC) is a trade association in the United States construction industry, with headquarters in Arlington, Virginia.
History
The AGC was founded in November, 1918 to address problems identified during World War I. In 1912, the federal government asked the U.S. Chamber of Commerce to bring all industry associations together under its umbrella. AGC's founding members attended a Chamber-led meeting in Atlantic City, New Jersey in the spring of 1918, but felt it was geared too much toward subcontractors. In the fall of 1918, the group that would later become the founding members met in Chicago and subsequently formed AGC.
Membership
AGC represents over 6,500 of America’s general contractors, and over 9,000 specialty-contracting firms. More than 10,500 service providers and suppliers are also associated with AGC, through a nationwide network of chapters.
References
External links
AGC website
Construction organizations
Construction industry of the United States
Organizations established in 1918
1918 establishments in the United States
Organizations based in Arlington County, Virginia | Associated General Contractors of America | [
"Engineering"
] | 214 | [
"Construction",
"Construction organizations"
] |
47,720,752 | https://en.wikipedia.org/wiki/Kepler-371b | Kepler-371b (also known as KOI-2194.01, K02194.01, KIC 3548044 b) is a confirmed Super-Earth sized exoplanet, orbiting around the G-type star Kepler-371 every 35 days about 2,700 light-years away from Earth.
References
371b
b
Super-Earths
Exoplanets discovered in 2014
Cygnus (constellation) | Kepler-371b | [
"Astronomy"
] | 93 | [
"Cygnus (constellation)",
"Constellations"
] |
47,720,780 | https://en.wikipedia.org/wiki/Kepler-371c | Kepler-371c (also known as KOI-2194.02, K02194.02, KIC 3548044 c) is a confirmed Super-Earth sized exoplanet. Orbiting around the F-type star Kepler-371 every 68 days about 1914 ly away from the Earth. It is a member of the multi planetary system of Kepler-371.
References
371c
c
Super-Earths
Exoplanets discovered in 2014
Transiting exoplanets
Cygnus (constellation) | Kepler-371c | [
"Astronomy"
] | 112 | [
"Cygnus (constellation)",
"Constellations"
] |
47,720,857 | https://en.wikipedia.org/wiki/Kepler-371 | Kepler-371 (also known as KOI-2194 or KIC 3548044) is a star some 2,680 ly away from the Earth. It hosts a multi planetary system consisting of 2 confirmed Super-Earths, as well as 1 unconfirmed Near-Earth sized exoplanet in its habitable zone.
References
Planetary systems with two confirmed planets
Cygnus (constellation)
Planetary transit variables | Kepler-371 | [
"Astronomy"
] | 88 | [
"Cygnus (constellation)",
"Constellations"
] |
47,720,961 | https://en.wikipedia.org/wiki/HWCG%20LLC | HWCG LLC is a non-profit consortium of deep water oil and gas companies. HWCG maintains a comprehensive deepwater well containment response model that can be activated immediately in the event of a US Gulf of Mexico subsea blowout. It comprises oil and gas companies operating in the Gulf and incorporates the consortium’s generic well containment plan. HWCG has a healthy mutual aid component whereby HWCG members will respond and support another member’s incident.
History
After the Deepwater Horizon oil spill, President Obama announced a drilling moratorium on new permits for offshore wells and exploration in the Gulf of Mexico came to a standstill. In response to the suspension, twenty-four deepwater operators came together to establish well containment resources and plans according to the guidelines set forth in BOEMRE’s (BSEE’s) Notice To Lessees No. 2010-N10. These offshore oil and gas companies formed HWCG LLC with the common goal of establishing and maintaining the capability to quickly and comprehensively respond to a subsea blowout.
Response System Capabilities
The consortium’s response system builds on the equipment proven effective in the containment of the Deepwater Horizon blowout, including the Helix Fast Response System with the Q4000 intervention vessel and Helix Producer 1 from Helix Energy Solutions Group.
HWCG’s core equipment includes two dual-ram capping stacks capable of operating in water depths through 10,000 feet. These capping stacks can effectively shut-in and contain a subsea well. If a flow and capture is required, the system is capable of a process volume of 130,000 barrels of oily fluids per day and 220 million cubic feet of gas per day.
HWCG maintains contracts and operating agreements with over thirty service providers to leverage additional expertise, assistance and equipment. This integrated response solution yielded a tested deployment response time of less than seven days to cap a deepwater well, compared to the nearly 90 days needed to contain the Deepwater Horizon blowout.
HWCG continues to run annual subsea incident response drills and collaborates with members, service sector companies and regulators in order to continually test and improve its response plan.
References
Petroleum organizations
Petroleum industry in the United States
Trade associations based in the United States | HWCG LLC | [
"Chemistry",
"Engineering"
] | 454 | [
"Petroleum",
"Petroleum organizations",
"Energy organizations"
] |
47,721,784 | https://en.wikipedia.org/wiki/Louise%20Chow | Louise Tsi Chow () is a Taiwanese biochemist and molecular geneticist. She is a professor of biochemistry and molecular genetics at the University of Alabama at Birmingham and a foreign associate with the National Academy of Sciences, known for her research on the human papillomavirus. Her research contributed to the discovery of gene splicing, and in 1993, her collaborator, Richard J. Roberts, received the Nobel Prize for the research, leading some to assert that Chow should have received the honor as well.
Early life and education
Chow was born in Hunan Province, Republic of China. Her father Chou Te-wei (周德偉) was a well known economist who worked in the Ministry of Finance of the Republic of China on Taiwan and student to Hayek.
She studied agricultural chemistry at National Taiwan University, graduating in 1965 before moving to California to pursue graduate studies in chemistry at the California Institute of Technology, earning her Ph.D in 1973. She then undertook post-doctoral training at the University of California, San Francisco, researching the monkey tumor virus SV40.
Career
Chow and her husband, fellow scientist Thomas Broker, joined Cold Spring Harbor Laboratory in 1975. It was here that, in the process of studying the genetic organization, DNA transcription, and RNA translation of adenoviruses, she and her colleagues discovered RNA splicing in 1977. This finding led to her collaborator, Richard Roberts, winning the 1993 Nobel Prize in Physiology or Medicine (shared with Phillip Sharp from MIT whose team independently made the discovery). Many feel that Chow deserved a share of the prize (see Nobel Prize controversy).
In 1984, she took a job with the University of Rochester School of Medicine, studying the genome of the human papillomavirus (HPV). Chow became a professor at the University of Alabama at Birmingham (UAB) in 1993, studying genetics and virology, focusing on diseases such as cancer, cystic fibrosis, and AIDS.
At UAB, Chow developed a method to produce large amounts of one of the most dominant cancer-causing HPV strains, HPV-18, in the laboratory, enabling her and her team to study HPV's entire replicative cycle.
Nobel Prize controversy
In 1993, her collaborator at Cold Spring Harbor Laboratory, Richard J. Roberts, was awarded the Nobel Prize, along with researcher Phillip Sharp, for the discovery of RNA splicing. Roberts called the award a "tribute" to his co-workers, including Chow. However, other scientists felt that Chow, who operated the electron microscope that allowed researchers to observe the splicing process, should have been included among the scientists awarded the Nobel Prize for the research. Chow told the Boston Globe that her contributions "were not trivial... it was a new type of experiment and needed to be designed and set up."
Key publications
Selected honors
Foreign Associate of the National Academy of Sciences, 2012
Member of Academia Sinica
References
Women biochemists
Chemists from Hunan
National Taiwan University alumni
California Institute of Technology alumni
University of Alabama at Birmingham faculty
Chinese emigrants to the United States
Living people
Taiwanese people from Hunan
Taiwanese women scientists
Chinese women biologists
Chinese women chemists
Taiwanese biochemists
Members of Academia Sinica
Foreign associates of the National Academy of Sciences
Year of birth missing (living people)
Educators from Hunan
Biologists from Hunan
Fellows of the American Academy of Microbiology | Louise Chow | [
"Chemistry"
] | 683 | [
"Biochemists",
"Women biochemists"
] |
47,722,746 | https://en.wikipedia.org/wiki/Christina%20Lampe-%C3%96nnerud | Maria Christina Lampe-Önnerud (born 4 February 1967) is a Swedish inorganic chemist, battery-inventor, and entrepreneur. She has founded the companies Boston-Power Inc. (2005–2012) and Cadenza Innovation (initially called CloTeam, 2012). She is developing batteries for use in computers, electric vehicles, and grid storage. She has received a number of awards, including the World Economic Forum's Technology Pioneer Award in 2010 and again in 2018, and is an elected member of the Royal Swedish Academy of Engineering Sciences. Lampe-Önnerud has many interests, including opera singing, jazz dancing, playing the cello, and choir directing.
Biography
Early life
Christina Lampe-Önnerud was born in Sweden. Her father, Wolfgang Lampe, was a power engineer. Lampe-Önnerud had an interest in science early on, making fireworks in a basement bathtub and playing with chemistry and electrical kits as a child. She was also trained as an opera singer.
Education
Lampe-Önnerud considered careers in opera singing and medicine and was offered a scholarship for an 8-year program for a medical doctorate degree but turned it down her senior year of high school. After high school, Lampe-Önnerud accepted a Fulbright scholarship to attend Elmira College in New York. At Elmira college she studied English literature, business, and the sciences while working in a chemistry laboratory as a lab assistant.
With encouragement from her father to pursue a career in a STEM field and her growing interest in the sciences, Lampe-Önnerud returned to Sweden and obtained a BSc in Chemistry and a PhD in inorganic chemistry from Uppsala University in Sweden. In her masters program at Uppsala, Lampe-Önnerud studied copper deposition on semiconductor wafers, and for her PhD she focused on analyzing cathode materials for lithium-polymer batteries while working with a Denmark battery producer, Danionics, who later patented some of the materials Lampe- Önnerud studied.
Lampe-Önnerud then held a postdoctoral appointment at MIT in Cambridge, MA working for Quantum Energy Technologies. This was sponsored by the American Chemical Society.
Personal life
Lampe-Önnerud is married to Per Önnerud, who she met in high school. She has two children, Anna-Maria and Mattias.
From 2002 until 2020, she served as the Director and Chairman of the non-profit Stardust Show Chorus and is currently the director of Silk'n'Sounds, an auditioned chorus of women based in the Greater New Haven area bound together by their love of singing. They strive to be an organization that values and celebrates diversity among its members — empowering women to rise to their highest level of musicality through singing and performing. (https://www.silknsounds.org/join-us#director)
Career
Lampe-Önnerud has focused her career on energy storage since her time at Uppsala University, where her father had an interest in power generation. While still a doctoral student, Lampe-Önnerud patented a material to increase the power of lithium batteries. She joined Bell Communications Research in New Jersey in 1995, as a director and senior scientist, working on prototypes for thin-film polymer lithium batteries. She later became one of the youngest partners at Arthur D. Little (whose research section was acquired by TIAX), in charge of the company's battery labs.
She founded the lithium-ion battery company Boston-Power Inc. in 2005 and owned the company until 2012 working as the CEO, executive chairman, and international chairman. The company focused on lithium-ion batteries for small personal computing devices.
From 2007 to 2009, Lampe-Önnerud was assigned by Club de Madrid and the United Nations to serve of Road to Copenhagen as Energy Expert and in 2008, she was a member of the United States' State Department's delegation to China, hosted by the Ministry of Commerce, PRC, and Chinese Academies of Science.
In 2009, Lampe-Önnerud was a member of the European Union's Presidential delegation to China and Premier Wen Jiabao, dealing with subjects such as clean technology deployment, CSR, and international trade. Additionally, starting in 2009, Lampe-Önnerud was elected Co-Chairman of the Global Future Council on Energy at the World Economic Forum. She serves on multiple working groups and as a speaker at the WEF on topics ranging from global innovation to renewable transport and finance. She is active in multiple forums throughout the United States, China, and the EU.
In 2010, she became a Lifetime Member of the Swedish Royal Academy of Engineering Sciences.
Lampe-Önnerud served on the Ernst & Young Entrepreneur of the Year Advisory Board from 2010 through 2013, the Wall Street Journal Economist Advisory Council from 2011 through 2013, and the United Nations Inter Academy Panel (IAP) and Inter Academy Council from 2011 through 2014.
From 2011 through 2013, Lampe-Önnerud served as the Director of the New England Clean Energy Council.
In 2012, she and her husband Per Önnerud started the company CloTeam, later renamed Cadenza Innovation, based in Oxford, Connecticut. Her work aims at developing efficient, safe, lasting, and inexpensive batteries for various technologies, including computers, phones, and cars.
The lithium-ion battery she invented is the first to be considered environmentally friendly while capable of providing long-lasting energy safely to various types of technology. She describes Cadenza's 2016 battery design, which involves a ceramic insert in an aluminum container, as "an energy LEGO-brick for engineers". It is intended to be a power source for electric vehicles such as Tesla's cars, but could also be used in electrical grids. Lampe-Önnerud continues to serve as the Founder, chief executive officer, and Director at Cadenza.
Lampe-Önnerud became a Lifetime Ambassador of Honor in Dalarna, Sweden in 2013. In 2013–2014, Lampe-Önnerud served as the Senior Manager and Management Committee Advisor in the Core Management Group at Bridgewater Associates in Westport, Connecticut. She worked closely with the CEO and Management Committee members during an extensive transition at this hedge fund, focusing on change in management centering around talent, cost, and efficiency.
From 2016 through 2019, Lampe-Önnerud served as the non-executive director of Syrah Resources Limited, an Australian-based company focusing on minerals and technology for industrial use. Lampe-Önnerud has served as a voice for power and energy issues at government and industrial conferences for over 15 years. Also starting in 2016, Lampe-Önnerud became a board member at the MIT Corporation Visiting Committee for the Department of Chemistry. Since 2016, she has also been a part of the NY-BEST (New York Battery and Energy Storage Technology) Consortium, appointed as Energy Storage Industry Director.
In 2018–2019, she held a board of directors appointment at FuelCell Energy and additionally joined the Future Battery Industry Collaborative Research Center advisory board and served from 2019-2022.
In 2019, Lampe-Önnerud was appointed to the Livent board of directors and has continued to serve on the Board through the 2023 Merger with Allkem to become Arcadium Lithium. Additionally, Christina Lampe-Önnerud has served as a director of ON Semiconductor Corporation since September 2023.
In April 2022 Lampe-Önnerud received one of Sweden's most prestigious awards – the King's Medal. The internationally respected, 25-year battery industry thought leader and entrepreneur was honored for her outstanding contribution to Swedish business.
Christina Lampe-Önnerud holds 80+ patents on designs, products, devices, components, materials, and processes. She has over 25 technical publications in scientific journals focusing on science and thought-leadership. She has also enjoyed over 30 interviews, on media such as TV, radio, and podcasts with select features on CNBC, WGBH, NECN, and NPR. Lampe-Önnerud is featured in 500+ articles with select features in the Wall Street Journal, Bloomberg News, Fortune, Nikkei, and China Daily. She has given over 100 keynote presentation with select events such as the World Economic Forum, TED, and CES. Lampe-Önnerud has served as a voice for power and energy issues at government and industrial conferences for over 15 years.
Published works
"Conference Paper: Opportunities in energy storage due to the paradigm shift fueled by the mobile and clean tech revolutions"
"A Consumer Revolution"
"Benchmark study on high performing carbon anode material"
"Conference Paper: Safety studies of Li-ion key components by ARC"
"Conference Paper: Safety studies on lithium-ion batteries by accelerating rate calorimetry"
Uppsala University Dissertation"Chemical and Electrochemical Intercalation of Lithium Into a V6O13 Host"
Honors and awards
2022 Royal Honorary Gold Medal (Sweden)
2021, Holds 80+ patents
2021, Women of Technology Award, Connected World magazine
2018, Technology Pioneer Award, World Economic Forum
2018, INC. Top 100 Female Founders
2018, Frost & Sullivan North American Lithium-Ion Industrial and Electric Vehicle Battery Technology Innovation Award
2015, CT Technology Council 2015 Women of Innovation: Entrepreneurial Innovation and Leadership Award
2013, Elected Lifetime Ambassador of Honor, Dalarna, Sweden
2011, Important Women in Mobile Tech
2011, Swedish woman of the year ('Årets svenska kvinna'), Swedish Women's Educational Association.
2010, Elected Lifetime Member of the Royal Swedish Academy of Engineering Sciences ('Kungliga ingenjörsvetenskapsakademien')
2010, Private Company CEO of the Year from the MassTLC Leadership Awards
2010, Technology Pioneer Award, World Economic Forum
2010, Sustainable Leadership Award, Swedish Association of Environmental Managers
2009, Entrepreneur Hall of Fame
2009, Ernst & Young Entrepreneur of the Year for Clean Tech, New England region
2008, Stevie Award for Women in Business as Best Entrepreneur
2008, Top Innovators of 2008, EDN Magazine
2007, Mass High Tech Women to Watch
2007, DEMOgod™
2006, Top 100 Woman-Led Businesses in MA
2002, 100 Top Young Innovators, MIT's Technology Review
1998, Bell Labs Spot Innovation Award
1994, Amelia Earhart International Fellowship
1989, Nobel Foundation Student Award
Popular culture
Christina Lampe-Önnerud presented an episode of the Sveriges Radio show Sommar i P1 on 25 June 2012.
References
1967 births
21st-century Swedish chemists
21st-century Swedish women scientists
Swedish chemists
Swedish women chemists
21st-century Swedish businesswomen
21st-century Swedish businesspeople
Inorganic chemists
Living people
Place of birth missing (living people)
Women inventors | Christina Lampe-Önnerud | [
"Chemistry"
] | 2,185 | [
"Inorganic chemists"
] |
47,722,772 | https://en.wikipedia.org/wiki/Maenianum | A maenianum was a balcony or gallery for spectators at a public show in ancient Rome. The name was originally given by censor Gaius Maenius in 318 BC to the decorated gallery in the Forum Romanum, where spectators watched gladiatorial combats.
The maenianum was divided into several levels: maenianum primum, which was reserved for the non-senatorial noble class called the equites. The maenianum secundum, which featured the better, lower seats for the wealthy plebeians; and maenianum summum with the upper seats for the poor plebeians.<ref>Codex Justinian 8:10:11. Imperatores Honorius], Theodosius: Maeniana, quae Graece εξωστας appellant, immersive olim Constructa sive in posterum in provinciis construenda, nisi spatium inter se by decem pedestinations liberi Aeris habuerint, MODIS omnibus detruncentur. .fr / DroitRomain / Corpus / CJ8.htm # 10</ref>
Literature
Maenius. In: Karl Ernst Georges: Concise Latin-German pocket dictionary. 8th edition. Volume 2, Hannover 1918, Sp. 755 (online).
KIP | 3 | 864 ||| Walter Hatto Gross
Philip Smith: maenianum. In: William Smith: . A Dictionary of Greek and Roman Antiquities '' John Murray, London, 1875. 723 S. ([https://penelope.uchicago.edu/Thayer/ E / novel / text / secondary / SMIGRA * /).
References
Architectural terminology
Ancient Roman architecture | Maenianum | [
"Engineering"
] | 368 | [
"Architectural terminology",
"Architecture"
] |
47,723,216 | https://en.wikipedia.org/wiki/Barry%20Bozeman | Barry Bozeman is a professor emeritus at Arizona State University where he was founding Director, Center for Organization Research and Design, Regents' Professor and Arizona Centennial Professor of Technology Policy and Public Management. He specializes in two disparate fields, organization theory and science and technology policy.
Early life and education
Bozeman was born in Birmingham, Alabama on January 18, 1947 to Glenn Bozeman and Audrey J. Bozeman (née Martin). His mother was a full-time homemaker and this father a construction worker. His early life was characterized by much family relocation, resulting in his attending 21 different schools before the 7th grade. In 1960, the family settled down in West Palm Beach, Florida and Bozeman graduated from Palm Beach High School in 1964. He attended Palm Beach High Junior College, in Lake Worth, Florida, (now Palm Beach State College), graduating in 1966. Bozeman played on the varsity baseball team at Palm Beach Junior College where he had the distinction of scoring the first run in the new team’s history.
In 1970, Bozeman entered the doctoral program in political science at Ohio State University, focusing on public policy studies. He graduated in 1973.
Career
In 1973, Bozeman began as an Assistant Professor of Political Science at Georgia Institute of Technology. During that period, he began specializing in Science and Technology Policy and in 1974, as part of the Intergovernmental Personnel Act, took a position as an analyst in the National Science Foundation’s Division of Information Science and Technology. After returning briefly to Georgia Tech, Bozeman took a job at the University of Missouri-Columbia, where he was appointed in the Department of Political Science, as well as the new Department of Public Administration.
In 1977, Bozeman began a long stay (1977-1993) at Syracuse University’s Maxwell School of Citizenship and Public Affairs. While at Syracuse, Bozeman was the Director of the Doctoral Program (1979-1986) and was the founding director of the Center for Technology and Information Policy. He was graduate advisor for Michael M. Crow.
He moved in 1993 to be the first full-time director of the new School of Public Policy at Georgia Tech and was later appointed as Regent’s Professor, the first social scientist to become a Regent’s Professor at Georgia Tech.
In 2006, Bozeman moved to University of Georgia where he became the first holder of the Department of Public Administration and Policy’s Ander Crenshaw Chair in Public Policy.
In 2013, Bozeman moved to Arizona State University where he is Arizona Centennial Professor of Technology Policy and Public Management and Director of the Center for Organization Research and Design.
Scholarly contributions
Bozeman’s chief contributions to organization theory and public administration include:
The theory of “dimensional publicness,” showing all organizations are affected by the constraints and endowment of political authority and of market authority and that behavior can be predicted from the mix of these forces.
The normative “public value theory,” set as an alternative to market failure theory and suggesting that public values can be attained by a variety of institutions, public and private, acting separately or together.
Theory and empirical research on organizational red tape and bureaucratic pathologies.
Bozeman’s chief contributions to science and technology policy include:
Research and theory on technology transfer, suggesting that a wide variety of outcome measures should be embraced (“contingent theory of effectiveness”) rather than solely short-term market impacts.
Research and theory on scientific collaboration, both at the level of the individual researcher and the scientific organization or research center.
Honors and awards
NASPAA/ASPA Distinguished Researcher Award (2014)
George Fredrickson Award, Public Management Research Association (2013), for lifetime of intellectual contributions to the field of public management, 2013
Herbert Simon Award, American Political Science Association (2013), best book on public administration topic, 2007-2012 (Public Values and Public Interest, Georgetown University Press 2007)
Fellow, American Association for the Advancement of Science, elected 2005
Fellow, National Academy of Public Administration , elected 2006.
Charles Levine Award, National Association for Schools of Public Affairs and Administration and American Society for Public Administration, career award for research, teaching and professional service (national award recognizing one academic scholar each year), 2000
Fulbright Fellowships, University of Copenhagen, 1989–90, Valencia Polytechnic and INGENIO, 2012
Personal life
Barry Bozeman and his wife Monica Gaughan live in Tempe, Arizona. Dr. Gaughan, a sociologist, is a faculty member at Arizona State University. Bozeman has three children.
Selected publications
Books
Barry Bozeman and Craig Boardman, Research Collaboration and Team Science: A State-of-the-Art Review and Agenda (Springer Publishing, 2014).
Barry Bozeman and Mary Feeney, Rules and Red Tape Research: A Prism for Understanding Theory Development in Public Administration (Sharpe Publishing, 2011).
Barry Bozeman, Public Values and Public Interest: Counterbalancing Economic Individualism (Georgetown University Press, 2007). [Awarded Herbert Simon Award of the American Political Science Association, best book in Public Administration during period 2007-2012].
Barry Bozeman, Bureaucracy and Red Tape (Englewood Cliffs, N.J.:Prentice-Hall, 2000).
Michael Crow and Barry Bozeman, Limited by Design: R&D Laboratories in the United States (New York: Columbia University Press, 1998)
Barry Bozeman, All Organizations are Public: Bridging Public and Private Organization Theory (San Francisco: Jossey-Bass Publishing, 1987).
Articles
This list only contains articles from 2000 onward.
References
External links
Faculty website
Curriculum Vita
Center for Organization Research and Design website
1947 births
Living people
People from Birmingham, Alabama
People from West Palm Beach, Florida
American social scientists
Arizona State University faculty
Georgia Tech faculty
Palm Beach State College alumni
John Glenn College of Public Affairs alumni
University of Missouri faculty
Science and technology studies scholars
Syracuse University faculty
University of Georgia faculty | Barry Bozeman | [
"Technology"
] | 1,213 | [
"Science and technology studies",
"Science and technology studies scholars"
] |
47,723,295 | https://en.wikipedia.org/wiki/Garbage | Garbage, trash (American English), rubbish (British English), or refuse is waste material that is discarded by humans, usually due to a perceived lack of utility. The term generally does not encompass bodily waste products, purely liquid or gaseous wastes, or toxic waste products. Garbage is commonly sorted and classified into kinds of material suitable for specific kinds of disposal.
Terminology
The word garbage originally meant chicken giblets and other entrails, as can be seen in the 15th century Boke of Kokery, which has a recipe for Garbage.
What constitutes garbage is highly subjective, with some individuals or societies tending to discard things that others find useful or restorable. The words garbage, refuse, rubbish, trash, and waste are generally treated as interchangeable when used to describe "substances or objects which the holder discards or intends or is required to discard". Some of these terms have historic distinctions that are no longer present. In the 1880s, material to be disposed of was divided into four general categories: ashes (derived from the burning of coal or wood), garbage, rubbish, and street-sweepings. This scheme of categorization reduced some of these terms to more specific concepts:
The distinction between terms used to describe wet and dry discarded material "was important in the days when cities slopped garbage to pigs, and needed to have the wet material separated from the dry", but has since dissipated.
Treatment
In urban areas, garbage of all kinds is collected and treated as municipal solid waste; garbage that is discarded in ways that cause it to end up in the environment, rather than in containers or facilities designed to receive garbage, is considered litter. Litter is a form of garbage that has been improperly disposed of, and which therefore enters the environment. Notably, however, only a small fraction of garbage that is generated becomes litter, with the vast majority being disposed of in ways intended to secure it from entering the environment.
History
Humans have been creating garbage throughout history, beginning with bone fragments left over from using animal parts and stone fragments discarded from toolmaking. The degree to which groups of early humans began engaging in agriculture can be estimated by examining the type and quality of animal bones in their garbage. Garbage from prehistoric or pre-civilization humans was often collected into mounds called middens, which might contain things such as "a mix of discarded food, charcoal, shell tools, and broken pottery".
See also
Garbology (study of modern refuse and trash)
Landfill
Garbage truck
References
Waste | Garbage | [
"Physics"
] | 510 | [
"Materials",
"Waste",
"Matter"
] |
47,723,667 | https://en.wikipedia.org/wiki/Penicillium%20striatisporum | Penicillium striatisporum is an anamorph species of fungus in the genus Penicillium which was isolated from the rhizosphere of chilli peppers.
Penicillium striatisporum has a selective antifungal activity against Candida albicans This species produces striatisporin A, striatisporolide A, , calbistrin C, deformylcalbistrin A, citromycetin, citromycin, fulvic acid, (-)-2,3-dihydrocitromycetin and (+)-hexylitaconic acid
References
Further reading
striatisporum
Fungi described in 1969
Fungus species | Penicillium striatisporum | [
"Biology"
] | 155 | [
"Fungi",
"Fungus species"
] |
47,723,676 | https://en.wikipedia.org/wiki/Manav%20%28robot%29 | Manav (Sanskrit: मानव, pronounced "Maanav"/Mɑnʌv, meaning "human") is a humanoid robot developed in the laboratory of A-SET Training and Research Institutes by Diwakar Vaish (Head of Robotics and Research, A-SET Training and Research Institutes) in late December 2014. It debuted at the IIT-Bombay Techfest 2014-2015 in Mumbai.
Technical specifications
Manav is 2 feet tall and weighs 2 kilograms. It has a rechargeable lithium polymer battery. Manav's outer body was designed in A-SET's 3D printing laboratory and is made of acrylonitrile butadiene styrene (ABS) plastic. It has a total of 21 degrees of freedom, two of which provide head movement allowing it to nod and look around. 1 degree of freedom goes to the waist which allows it to articulate the waist movement, allowing for a more human-like movement. The Robot is also equipped with Wi-Fi and Bluetooth connectivity. It could perpetrate various activities like walking and dancing using human voice commands. It uses binocular vision processing, giving it the ability to perceive depth and perspective.
References
Humanoid robots
Bipedal humanoid robots
Entertainment robots
Social robots
Robots of India | Manav (robot) | [
"Technology"
] | 263 | [
"Social robots",
"Computing and society"
] |
47,724,378 | https://en.wikipedia.org/wiki/Indexed%20category | In category theory, a branch of mathematics, a C-indexed category is a pseudofunctor from Cop to Cat, where Cat is a 2-category of categories. Any indexed category has an associated Grothendieck construction, which gives rise to a fibred category.
References
Category theory | Indexed category | [
"Mathematics"
] | 62 | [
"Functions and mappings",
"Mathematical structures",
"Category theory stubs",
"Mathematical objects",
"Fields of abstract algebra",
"Category theory",
"Mathematical relations"
] |
47,725,139 | https://en.wikipedia.org/wiki/NGC%20235 | NGC 235 is a lenticular galaxy in the constellation of Cetus. Its companion, PGC 2570, appears in the line of sight of NGC 235, but has no relation with NGC 235. This pair was first discovered by Francis Leavenworth in 1886. Dreyer, the compiler of the catalogue, described the galaxy as "extremely faint, small, round, brighter middle and nucleus".
References
External links
Lenticular galaxies
?
0235
Cetus | NGC 235 | [
"Astronomy"
] | 93 | [
"Cetus",
"Constellations"
] |
47,725,427 | https://en.wikipedia.org/wiki/Secondary%20organic%20aerosol | A secondary organic aerosol (SOA) is a molecule produced via oxidation over several generations of a parent organic molecule. In contrast to primary organic aerosols, which are emitted directly from the biosphere, SOAs are either formed via homogeneous nucleation through the successive oxidation of gas-phase organic compounds, or through condensation on pre-existing particles. These gas-phase species exert high vapor pressures, meaning they are volatile and stable in the gas-phase.
Upon oxidation, the increased polarity, and thus reduced volatility, of the molecules results in a reduction of vapor pressure. After sufficient oxidation, the vapor pressure is sufficiently low that the gas-phase compound partitions into the solid-phase, producing secondary organic matter (the particle phase of SOA).
SOAs represent a significant proportion of aerosols contained in the troposphere.
References
Bibliography
Aerosols
Atmosphere of Earth
Atmospheric dynamics | Secondary organic aerosol | [
"Chemistry"
] | 189 | [
"Atmospheric dynamics",
"Colloids",
"Organic compounds",
"Aerosols",
"Organic compound stubs",
"Organic chemistry stubs",
"Fluid dynamics"
] |
47,725,527 | https://en.wikipedia.org/wiki/XX%20Pyxidis | XX Pyxidis is a star located in the constellation Pyxis. It has an apparent magnitude that varies slightly at about 11.5, and is about 2,300 light years away.
XX Pyxidis is one of the more-studied members of a class of stars known as Delta Scuti variables—short-period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. Astronomers made more sense of its pulsations when it became clear that it is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85 times as massive as the Sun. Its companion is most likely a red dwarf star of spectral type M3V, around 0.3 times as massive as the Sun. The two are very close—possibly only 3 times the diameter of the Sun between them—and orbit each other every 1.15 days. The brighter star is deformed into an egg-shape, and pulsates in several overlapping modes 26-76 times per day.
References
Pyxis
Pyxidis, XX
Delta Scuti variables
CD-24 7599
J08583903-2435106
A-type main-sequence stars
M-type main-sequence stars
Binary stars | XX Pyxidis | [
"Astronomy"
] | 276 | [
"Pyxis",
"Constellations"
] |
47,725,880 | https://en.wikipedia.org/wiki/BANA%20test | The BANA test (referring to the enzymatic breakdown of [N-benzoyl-dL-arginine-2-napthylamide]) is used to determine the proteolytic activity of certain oral anaerobes that contribute to oral malodor. Some bacteria, e.g. Prophyromona gingivalis, Treponema denticola, and Bacteroides forsythus (Red complex) produce waste products that are quite odiferous, and as a result contribute to bad breath.
When a sample of a patient's saliva that contains these bacteria is placed within the BANA testing compound, it causes the breakdown of the N-benzoyl enzyme. As a result of this biodegradation occurs, the test compound changes color, indicating a positive reaction.
Uses: Used to identify volatile Sulphur compounds in halitosis patients.
References
Further reading
Biodegradation
Metabolism
Oral hygiene | BANA test | [
"Chemistry",
"Biology"
] | 195 | [
"Biodegradation",
"Biochemistry",
"Metabolism",
"Cellular processes"
] |
56,221,905 | https://en.wikipedia.org/wiki/BlueBorne%20%28security%20vulnerability%29 | BlueBorne is a type of security vulnerability with Bluetooth implementations in Android, iOS, Linux and Windows. It affects many electronic devices such as laptops, smart cars, smartphones and wearable gadgets. One example is . The vulnerabilities were first reported by Armis, the asset intelligence cybersecurity company, on 12 September 2017. According to Armis, "The BlueBorne attack vector can potentially affect all devices with Bluetooth capabilities, estimated at over 8.2 billion devices today [2017]."
History
The BlueBorne security vulnerabilities were first reported by Armis, the asset intelligence cybersecurity company, on 12 September 2017.
Technical Information
The BlueBorne vulnerabilities are a set of 8 separate vulnerabilities. They can be broken down into groups based upon platform and type. There were vulnerabilities found in the Bluetooth code of the Android, iOS, Linux and Windows platforms:
Linux kernel RCE vulnerability - CVE-2017-1000251
Linux Bluetooth stack (BlueZ) information Leak vulnerability - CVE-2017-1000250
Android information Leak vulnerability - CVE-2017-0785
Android RCE vulnerability #1 - CVE-2017-0781
Android RCE vulnerability #2 - CVE-2017-0782
The Bluetooth Pineapple in Android - Logical Flaw CVE-2017-0783
The Bluetooth Pineapple in Windows - Logical Flaw CVE-2017-8628
Apple Low Energy Audio Protocol RCE vulnerability - CVE-2017-14315
The vulnerabilities are a mixture of information leak vulnerabilities, remote code execution vulnerability or logical flaw vulnerabilities. The Apple iOS vulnerability was a remote code execution vulnerability due to the implementation of LEAP (Low Energy Audio Protocol). This vulnerability was only present in older versions of the Apple iOS.
Impact
In 2017, BlueBorne was estimated to potentially affect all the 8.2 billion Bluetooth devices worldwide, although they clarify that 5.3 billion Bluetooth devices are at risk. Many devices are affected, including laptops, smart cars, smartphones and wearable gadgets.
In 2018, after one year after the original disclosure, Armis estimated that over 2 billion devices were still vulnerable.
Mitigation
Google provides a BlueBorne vulnerability scanner from Armis for Android.
Procedures to help protect devices from the BlueBorne security vulnerabilities were reported by September 2017.
References
External links
Computer security
2017 in computing
Cybersecurity engineering | BlueBorne (security vulnerability) | [
"Technology",
"Engineering"
] | 515 | [
"Cybersecurity engineering",
"Computer networks engineering",
"Computer engineering"
] |
56,221,934 | https://en.wikipedia.org/wiki/Dataism | Dataism is a term that has been used to describe the mindset or philosophy created by the emerging significance of big data. It was first used by David Brooks in The New York Times in 2013. The term has been expanded to describe what historian Yuval Noah Harari, in his book Homo Deus: A Brief History of Tomorrow from 2015, calls an emerging ideology or even a new form of religion, in which "information flow" is the "supreme value". In art, the term was used by Albert-Laszlo Barabasi to refer to an artist movement that uses data as its primary source of inspiration.
History
"If you asked me to describe the rising philosophy of the day, I'd say it is Data-ism", wrote David Brooks in The New York Times in February 2013. Brooks argued that in a world of increasing complexity, relying on data could reduce cognitive biases and "illuminate patterns of behavior we haven't yet noticed".
In 2015, Steve Lohr's book Data-ism looked at how Big Data is transforming society, using the term to describe the Big Data revolution.
In his 2016 book Homo Deus: A Brief History of Tomorrow, Yuval Noah Harari argues that all competing political or social structures can be seen as data processing systems: "Dataism declares that the universe consists of data flows, and the value of any phenomenon or entity is determined by its contribution to data processing" and "we may interpret the entire human species as a single data processing system, with individual humans serving as its chips." According to Harari, a Dataist should want to "maximise dataflow by connecting to more and more media". Harari predicts that the logical conclusion of this process is that, eventually, humans will give algorithms the authority to make the most important decisions in their lives, such as whom to marry and which career to pursue. Harari argues that Aaron Swartz could be called the "first martyr" of Dataism.
In 2022, Albert-László Barabási coined the term "Dataism" to define an artistic movement that positions data as the central means of understanding nature, society, technology, and human essence. This movement underscores the necessity for art to integrate with data to stay relevant in contemporary society.
Dataism responds to the intricacy and interconnectedness of modern social, economic, and technological realms, which exceed individual understanding. Advocating for the use of methodologies from various fields like science, business, and politics in art, Dataism sees this fusion as essential for art to retain its significance and influence.
Criticism
Commenting on Harari's characterisation of Dataism, security analyst Daniel Miessler believes that Dataism does not present the challenge to the ideology of liberal humanism that Harari claims, because humans will simultaneously be able to believe in their own importance and that of data.
Harari himself raises some criticisms, such as the problem of consciousness, which Dataism is unlikely to illuminate. Humans may also find out that organisms are not algorithms, he suggests. Dataism implies that all data is public, even personal data, to make the system work as a whole, which is a factor that's already showing resistance today.
Other analysts, such as Terry Ortleib, have looked at the extent to which Dataism poses a dystopian threat to humanity.
The Facebook–Cambridge Analytica data scandal showed how political leaders manipulated Facebook's users' data to build specific psychological profiles that went on to manipulate the network. A team of data analysts reproduced the AI technology developed by Cambridge Analytica around Facebook's data and was able to define the following rules: 10 likes enables a machine to know a person like a coworker, 70 likes like a friend would, 150 likes like a parent would, 300 likes like a lover would, and beyond it may be possible to know a people better than they know themselves.
See also
Transhumanism
Futurism
Surveillance capitalism
Facebook–Cambridge Analytica data scandal
References
External links
Techopedia definition of Dataism
Wired: 'Homo sapiens is an obsolete algorithm': by Yuval Noah Harari
Steve Lohr on Data-ism
The Dataist Organization
Digital Revolution
Philosophy of life
Philosophical schools and traditions
Big data
Posthumanism
Data
Philosophy of computer science
Philosophy of artificial intelligence | Dataism | [
"Mathematics",
"Technology"
] | 885 | [
"Digital Revolution",
"Philosophy of computer science",
"Computer science",
"Information technology",
"Data",
"Big data",
"History of computing"
] |
56,222,667 | https://en.wikipedia.org/wiki/Monosiphonous%20algae | Monosiphonous algae are algae which consist of a single row of cells with, or without, cortication.
See also
Polysiphonous
References
Algae | Monosiphonous algae | [
"Biology"
] | 34 | [
"Algae stubs",
"Algae"
] |
56,223,208 | https://en.wikipedia.org/wiki/Ozarkcollenia | Ozarkcollenia is an extinct genus of stromatolite-making cyanobacteria from Missouri, United States. It was related to Collenia. Ozarkcollenia may have formed in a lake of volcanic origin. The fossils of Ozarkcollenia laminata have been dated to the Proterozoic eon, about 1.5 billion years ago. It occurs in parts of Missouri's Ozark Mountains.
References
†Ozarkcollenia
Stromatolites
Prehistoric bacteria | Ozarkcollenia | [
"Biology"
] | 105 | [
"Prehistoric bacteria",
"Bacteria"
] |
56,223,229 | https://en.wikipedia.org/wiki/Osteopygis | Osteopygis is a genus of extinct turtle. Osteopygis, as traditionally seen, is a chimera: the postcrania (including the holotype) belong to a non-marine stem-cryptodire, whilst the crania belong to sea turtles. In 2005, the referred material was split between two taxa: the postcrania remained in Osteopygis, while the crania were reassigned to Euclastes wielandi.
References
Macrobaenidae
Late Cretaceous turtles
Paleogene turtles
Nomina dubia
Fossil taxa described in 1868
Taxa named by Edward Drinker Cope | Osteopygis | [
"Biology"
] | 129 | [
"Biological hypotheses",
"Nomina dubia",
"Controversial taxa"
] |
56,223,647 | https://en.wikipedia.org/wiki/%C5%A0umadija%20%28multiple%20rocket%20launcher%29 | The Šumadija (named for Šumadija region) is a Serbian self-propelled multiple rocket launcher in development since 2017. It is based on Kamaz truck chassis and it is modular in design. It can launch 4 400mm up to 285 km range or 12 rockets 262mm up to 75 km range.
History
Development is partially based on experience gained on M-87 Orkan and KOL 15 - VERA 120 km 400mm rocket program developed by Military Technical Institute Belgrade in the 1980s and further development of these projects in the late 1990s and after 2000.
Characteristics
One battery usually consist of 3-6 launch weapons in artillery division or in bigger formation as a battalion or regiment with 9-18 launch vehicles. Included in formations is command, reload, communication, workshop and fuel vehicles together with combat support vehicles type of BOV M16 Miloš that protects unit on march or in battle position against close enemy threats.
Using modern C4I2 battle management software together with UAV for guidance and observation, satellite, radar and other surveillance data and thanks to high missile precision it is very effective weapon for destroying command centers, airports, large enemy army groups and other valuable targets.
Rockets
There is two type of rocket in use by Šumadija MLRS:
400mm tactical ballistic missile originally called "Šumadija" and now "Јерина-1" with range of 285 km and circular error probable less than 150 meters if missile rely only on Inertial navigation system or when using inertial navigation combined with GPS data CEP is less than 50 meters.
262mm rocket called "Jerina 2" with range of up to 75 km - this rocket represents direct further development of Orkan MLRS rocket.
Jerina 1 400mm is rocket with correctable trajectory with warhead weight of 200 kg. Warhead is HE/fragmented with possible in future development thermobaric warhead would be on offer. Rocket weight is about 1550 kg and two rocket in one module weight 4200 kg. Rocket uses modern composite fuel. It is placed in container module made of steel.
Jerina 2 is 262mm rocket and comes with few type of warhead including HE/fragmented and 288 piece shaped charge bomblets type KB-2. It is placed in container module made of steel, possible future development of tubes used in LRSVM Morava.
Comparable systems
References
Multiple rocket launchers of Serbia
Modular rocket launchers
Military vehicles introduced in the 2010s | Šumadija (multiple rocket launcher) | [
"Engineering"
] | 497 | [
"Modular design",
"Modular rocket launchers"
] |
56,224,185 | https://en.wikipedia.org/wiki/NGC%204540 | NGC 4540 is a spiral galaxy with type 1 Seyfert activity located about 64 million light-years away in the constellation Coma Berenices. NGC 4540 was discovered by astronomer William Herschel on March 21, 1784 and is a member of the Virgo Cluster.
See also
List of NGC objects (4001–5000)
References
External links
Coma Berenices
Intermediate spiral galaxies
Seyfert galaxies
4540
41876
7742
Astronomical objects discovered in 1784
Virgo Cluster
Discoveries by William Herschel | NGC 4540 | [
"Astronomy"
] | 106 | [
"Coma Berenices",
"Constellations"
] |
56,225,402 | https://en.wikipedia.org/wiki/Guldbagge%20Award%20for%20Best%20Costume%20Design | The Guldbagge for Best Costume Design is a Swedish film award presented annually by the Swedish Film Institute (SFI) as part of the Guldbagge Awards (Swedish: "Guldbaggen") to costume designers working in the Swedish motion picture industry.
Winners and nominees
Each Guldbagge Awards ceremony is listed chronologically below along with the winner of the Guldbagge Award for Best Costume Design and the film associated with the award. In the columns under the winner of each award are the other nominees for best costume design.
2010s
2020s
See also
Academy Award for Best Costume Design
BAFTA Award for Best Costume Design
Critics' Choice Movie Award for Best Costume Design
Notes and references
External links
Awards established in 2011
Awards for film costume design
Costume design
Costume Design
Costume Design | Guldbagge Award for Best Costume Design | [
"Engineering"
] | 159 | [
"Costume design",
"Design"
] |
56,226,222 | https://en.wikipedia.org/wiki/Polyporus%20minutosquamosus | Polyporus minutosquamosus is a species of poroid fungus in the family Polyporaceae. Discovered in a tropical rainforest in Kaw, French Guiana, it was described as new to science in 2016 by mycologists Kadri Runnel and Leif Ryvarden. The fungus is characterized by a lateral stipe and fan-shaped caps with numerous small black scales. Phylogenetic analysis shows that although it is nested within the Polyporus sensu lato clade, it does not group with any of the subclades that have been previously identified in this genus.
References
Fungi described in 2016
Fungi of South America
minutosquamosus
Taxa named by Leif Ryvarden
Fungus species | Polyporus minutosquamosus | [
"Biology"
] | 148 | [
"Fungi",
"Fungus species"
] |
56,226,666 | https://en.wikipedia.org/wiki/Mensacarcin | Mensacarcin is a highly oxygenated polyketide first isolated from soil-dwelling Streptomyces bottropensis bacteria.
The molecule is a secondary metabolite, and can be obtained in large amounts from its producing organism.
Due to its unique properties it is an important model for drug development against melanoma and other cancers.
Medical properties
In NCI-60 anti-cancer compound screening mensacarcin has a high cytostatic effect against almost all cell lines (mean of 50% growth inhibition) and a relatively selective cytotoxic effect against melanoma cells.
Low COMPARE correlation with standard antitumor agents indicate a unique mechanism of action.
Further examinations reveal mensacarcin effecting the mitochondria.
Potential use in cancer therapy
With its unique mechanism,
effective also in BRAF V600E mutation cell lines,
mensacarcin is a promising model for the development of new anticancer drugs.
Existing therapies for melanoma are limited.
Mensacarcin's powerful effect against melanoma cells make it especially valuable for this disease.
Mechanism of action
Specific disruption of mitochondrial function
Mitochondria provide most of the energy used by eukaryotic cells.
In a study at the Oregon State University a synthesized fluorescent probe of mensacarcin was localized to the mitochondria within 20 minutes of treatment.
Live-cell bioenergetic flux analysis showed rapid disturbance of energy production and of mitochondrial function.
The localization together with the metabolic effects provide evidence that mensacarcin targets mitochondria.
Induction of cell death
Mitochondria are also important in cell death signaling.
Mensacarcin in melanoma cells activates apoptotic pathways related to caspase 3 and caspase 7, and thus induces cell death.
After mensacarcin treatment of two melanoma cell lines, the cells showed characteristic chromatin condensation as well as distinct poly(ADP-ribose)polymerase-1 cleavage;
flow cytometry identified a large population of apoptotic cells;
single-cell electrophoresis indicated that mensacarcin causes genetic instability, a sign of early apoptosis.
Effect in melanoma cell lines with BRAF V600E mutation
The BRAF V600E mutation is associated with drug resistance.
Due to its independent mechanism, mensacarcin has an undiminished effect in melanoma cell lines with this mutation (NCI 60 cell lines SK-Mel-28 and SK-Mel-5).
References
Polyketides
Oncology
Cancer research
Cancer
Melanoma | Mensacarcin | [
"Chemistry"
] | 545 | [
"Biomolecules by chemical classification",
"Natural products",
"Polyketides"
] |
56,226,811 | https://en.wikipedia.org/wiki/Hydnum%20albidum | Hydnum albidum, commonly known as the white hedgehog, is an edible species of fungus in the family Hydnaceae native to North America.
References
Cantharellales
Edible fungi
Fungi described in 1887
Fungi of North America
albidum
Fungus species | Hydnum albidum | [
"Biology"
] | 56 | [
"Fungi",
"Fungus species"
] |
56,227,208 | https://en.wikipedia.org/wiki/Haploporus%20latisporus | Haploporus latisporus is a species of poroid white rot crust fungus in the family Polyporaceae. It is found in Central China, where it grows on decomposing pine twigs.
Taxonomy
The type collection of Haploporus latisporus was made in Jigongshan (Henan Province) in August 2005, and described as a new species in 2007. The specific epithet latisporus refers to its wide spores, which, at up to 10 μm, are the broadest in genus Haploporus.
Description
Fruit bodies of Haploporus septatus occur in small crust-like patches that are difficult to separate from the underlying substrate. Individually, they measure up to long and wide, and up to 1 mm thick at the centre. The hymenophore, or pore surface, is white to cream coloured, darkening slightly in dry conditions. The round to angular pores number around two to three per millimetre.
The hyphal structure is dimitic to trimitic. The generative hyphae have clamp connections. The thick-walled, cylindrical spores are ornamented with warts (up to 2 μm long) and typically measure 13–16.5 by 8–10 μm.
References
Fungi described in 2007
Fungi of China
Polyporaceae
Taxa named by Yu-Cheng Dai
Fungus species | Haploporus latisporus | [
"Biology"
] | 280 | [
"Fungi",
"Fungus species"
] |
56,227,390 | https://en.wikipedia.org/wiki/Locomotor%20activity | Locomotor activity is a measure of animal behavior which is employed in scientific research.
Hyperlocomotion, also known as locomotor hyperactivity, hyperactivity, or increased locomotor activity, is an effect of certain drugs in animals in which locomotor activity (locomotion) is increased. It is induced by certain drugs like psychostimulants and NMDA receptor antagonists and is reversed by certain other drugs like antipsychotics and certain antidepressants. Stimulation of locomotor activity is thought to be mediated by increased signaling in the nucleus accumbens, a major brain area involved in behavioral activation and motivated behavior.
Hypolocomotion, also known as locomotor hypoactivity, hypoactivity, and decreased locomotor activity, is an effect of certain drugs in animals in which locomotor activity is decreased. It is a characteristic effect of many sedative agents and general anesthetics. Antipsychotics, which are dopamine receptor antagonists, and many serotonergic agents, such as meta-chlorophenylpiperazine (mCPP), can also produce this effect, often as a side effect.
Although locomotor activity is mainly an animal behavior test, it has also been evaluated in humans. People with attention deficit hyperactivity disorder (ADHD), in the manic phase of bipolar disorder, on acute amphetamine, and with schizophrenia show increased locomotor activity, while children with autism show decreased locomotor activity. Conversely, reduced locomotor activity is observed in bipolar individuals on mood stabilizers and may be a characteristic symptom of the inattentive type of ADHD (ADHD-PI) and sluggish cognitive tempo.
Drugs affecting locomotor activity
Dopaminergic agents
Dopamine releasing agents
Hyperlocomotion is induced by dopamine releasing agents (DRAs) and psychostimulants like amphetamine and methamphetamine. These drugs likewise induce stereotypies.
Dopamine reuptake inhibitors
The dopamine reuptake inhibitors (DRIs) amineptine, bupropion, and nomifensine increase spontaneous locomotor activity in animals. The DRI cocaine increases locomotor activity similarly to the preceding DRIs and to amphetamines. The atypical DRI modafinil does not produce hyperlocomotion in animals.
Dopamine receptor agonists
Direct dopamine receptor agonists like apomorphine show biphasic effects, decreasing locomotor activity at low doses and increasing locomotor activity at high doses.
Dopamine receptor antagonists
Drug-induced hyperlocomotion can be reversed by various drugs, such as antipsychotics acting as dopamine D2 receptor antagonists. Reversal of drug-induced hyperlocomotion has been used as an animal test of drug antipsychotic-like activity. Reversal of amphetamine- and NMDA receptor antagonist-induced stereotypies is also employed as a test of drug antipsychotic-like activity.
Adrenergic agents
Norepinephrine releasing agents
Selective norepinephrine releasing agents (NRAs) include ephedrine, pseudoephedrine, phenylpropanolamine, levomethamphetamine, and D-phenylalaninol. However, these drugs also release dopamine to a much lesser extent (e.g., ~10-fold less potently).
Ephedrine consistently stimulates locomotor activity in rodents. However, the hyperlocomotion induced by ephedrine may be mediated by dopamine release rather than by norepinephrine release. On the other hand, lesioning the brain noradrenergic system with the noradrenergic neurotoxin DSP-4 reduces dextroamphetamine-induced hyperlocomotion. In addition, the selective α1-adrenergic receptor antagonist prazosin antagonizes amphetamine-induced hyperlocomotion and knockout of the α1B-adrenergic receptor dramatically reduces dextroamphetamine-induced hyperlocomotion. In contrast to ephedrine and amphetamine, pseudoephedrine and phenylpropanolamine do not stimulate locomotor activity in rodents. However, in another study, pseudoephedrine was able to increase locomotor activity. A potential confounding factor with β-hydroxyamphetamines like phenylpropanolamine, ephedrine, and pseudoephedrine is that they have lower lipophilicity compared to their amphetamine counterparts, with consequent reduced capacity to cross the blood–brain barrier and produce central nervous system effects.
Conversely, the potencies of monoamine releasing agents (MRAs) in producing amphetamine-type subjective effects in humans have been found to correlate with their potency to induce norepinephrine release and not with their potencies to induce dopamine release. In addition, self-administration of methamphetamine appeared to be relatively resistant to blockade by dopamine receptor antagonists. Findings on the modulation of the ventral tegmental area by the noradrenergic locus coeruleus are mixed and suggestive of both excitatory and inhibitory roles. The α1-adrenergic receptor appears to be facilitatory, whereas the α2-adrenergic receptor appears to be inhibitory, and the β-adrenergic receptors appear to not be involved. More research is needed to investigate the role of norepinephrine in dopamine modulation and stimulant-like effects.
In contrast to normal mice, psychostimulants like amphetamine, β-phenethylamine, and methylphenidate lose their ability to elevate brain dopamine but not norepinephrine in dopamine transporter (DAT) knockout mice and have been found to decrease locomotor activity in these mice. Paradoxically however, cocaine retains reinforcing effects in DAT knockout mice and cocaine and amphetamine are still able to elevate dopamine in the medial nucleus accumbens in these mice. It was found that the norepinephrine reuptake inhibitor reboxetine increases dopamine levels in the nucleus accumbens in DAT knockout mice but not in normal mice, suggesting that the effects of norepinephrine elevation change in the brains of DAT knockout mice.
Whereas dextromethamphetamine is a well-balanced norepinephrine–dopamine releasing agent (NDRA), levomethamphetamine is a selective NRA. Levomethamphetamine has similar potency as an NRA compared to dextromethamphetamine. Conversely, levomethamphetamine is about 15- to 20-fold less potent in inducing dopamine release than dextromethamphetamine. In accordance with the preceding, levomethamphetamine was found to selectively induce brain norepinephrine release with minimal effect on brain dopamine release across an assessed dosage range in rodents. The drug did not increase locomotor activity at the assessed doses, in which brain dopamine release was not affected. In contrast to levomethamphetamine, dextromethamphetamine at the same doses increased brain levels of both norepinephrine and dopamine and induced dose-dependent hyperlocomotion. Relatedly, levomethamphetamine shows similar sympathomimetic effects as dextromethamphetamine but is substantially less potent as a psychostimulant in animals. As in rodents, levomethamphetamine showed reduced reinforcing and stimulant-like effects compared to dextromethamphetamine in rhesus monkeys.
Animal studies of the reinforcing and cocaine-like effects of dopamine releasing agents (DRAs) with varying capacities to release norepinephrine and serotonin in rodents and monkeys have suggested that in contrast to the case of serotonin release, which inhibits the reinforcing and stimulant-like effects of these agents, norepinephrine release has minimal influence on their misuse liability and associated effects.
Norepinephrine reuptake inhibitors
Norepinephrine reuptake inhibitors (NRIs), like atomoxetine, reboxetine, and desipramine, do not increase locomotor activity in rodents and instead show no effect on locomotor activity or decrease it. In addition, NRIs decrease amphetamine-, cocaine-, methylphenidate-, and phencyclidine (PCP)-induced hyperlocomotion in rodents. Accordingly, atomoxetine has been reported to attenuate the stimulant and rewarding effects of dextroamphetamine in humans.
A variety of different NRIs were shown to decrease spontaneous locomotor activity in a novel environment when given acutely and to decrease locomotor activity in both novel and familiar environments when given chronically in rodents. Similarly, norepinephrine transporter (NET) knockout mice had low basal locomotor activity. However, combination of an NRI with dopamine reuptake inhibition resulted in increased locomotor activity. It was concluded that norepinephrine reuptake inhibition by itself decreases locomotor activity unless it is combined with dopamine reuptake inhibition.
Serotonergic agents
Serotonin releasing agents
Certain serotonin releasing agents (SRAs), like MDMA and MDAI, though notably not others, like chlorphentermine, fenfluramine, and MMAI, induce locomotor hyperactivity in animals. This is dependent on serotonin release allowed for by the serotonin transporter (SERT) and serotonin 5-HT2B receptor. SERT knockout, pretreatment with serotonin reuptake inhibitors (SRIs) (which block MDMA-induced SERT-mediated serotonin release), or serotonin 5-HT2B receptor knockout (which likewise blocks MDMA-induced serotonin release), all completely block MDMA-induced locomotor hyperactivity. In addition, locomotor hyperactivity produced by MDMA is partially attenuated by serotonin 5-HT1B receptor antagonism (or knockout) or by serotonin 5-HT2A receptor antagonism. The locomotor hyperactivity produced by MDMA is fully attenuated by combined serotonin 5-HT1B and 5-HT2A receptor antagonism. Conversely, the serotonin 5-HT1A receptor is not involved in MDMA-induced hyperlocomotion. Serotonin 5-HT2C receptor activation appears to inhibit MDMA-induced hyperlocomotion, and antagonism of this receptor has been reported to markedly enhance the locomotor hyperactivity induced by MDMA. Activation of the serotonin 5-HT2C receptor is known to inhibit dopamine release in the mesolimbic pathway as well as to inhibit dopamine release in the nigrostriatal and mesocortical pathways.
Although the serotonin system has been implicated in the hyperlocomotion of SRAs, certain SRAs, such as MDMA, are actually serotonin–norepinephrine–dopamine releasing agents (SNDRAs), and catecholaminergic mechanisms are likely to additionally be involved. Relatedly, the α1-adrenergic receptor antagonist prazosin completely blocks MDMA-induced hyperlocomotion in animals. In addition, the α1-adrenergic receptor antagonists prazosin and doxazosin reduce the psychostimulant and/or euphoric effects of MDMA in humans. Similarly, the norepinephrine reuptake inhibitor (NRI) reboxetine, which prevents MDMA from inducing norepinephrine release, likewise reduces the stimulant effects and emotional excitation of MDMA in humans. Dopamine receptors also appear to be involved in MDMA-induced hyperlocomotion, although findings in this area, both in animals and humans, seem to be conflicting.
In contrast to non-selective SRAs like MDMA, the highly selective SRA MMAI induces hypolocomotion in animals. Similarly, the highly selective SRA chlorphentermine is said to weakly stimulate locomotor activity at low doses and to progressively suppress locomotor activity at higher doses.
The reasons for the differences in locomotor activity with different SRAs are not fully clear. In any case, they may be related to factors such as whether the agents are selective SRAs, whether they additionally act as agonists of serotonin 5-HT2 receptors, and whether they additionally induce the release of norepinephrine and/or dopamine.
Serotonin reuptake inhibitors
Selective serotonin reuptake inhibitors (SSRIs) have been reported to have no effect or to increase locomotor activity, at least under certain circumstances like novel environments. However, in other studies, SSRIs have been reported to produce hypolocomotion, an effect that could be reversed by the serotonin 5-HT2C receptor antagonist SB-242084. In another study, the SSRIs fluoxetine and citalopram had no effect on locomotor activity alone or in combination with SB-242084.
Fluoxetine has been found to not affect dextroamphetamine-induced hyperlocomotion. Similarly, sertraline did not affect cocaine-induced hyperlocomotion.
Serotonin precursors
The serotonin precursor 5-hydroxytryptophan (5-HTP) combined with benserazide can suppress the hyperlocomotion induced by dextroamphetamine in rodents.
Serotonin receptor agonists
The non-selective serotonin receptor agonists and serotonergic psychedelics LSD and DOI decrease locomotor activity in animals. However, whereas LSD suppresses locomotion at all doses tested, DOI as well as DOM show an inverted U-shaped dose–response curve, with stimulation of locomotor activity at low doses and suppression of locomotion at higher doses. The hyperlocomotion of DOI at low doses is abolished in serotonin 5-HT2A receptor knockout mice, whereas the hypolocomotion with DOI at higher doses is blocked by the selective serotonin 5-HT2C receptor antagonist SER-082. Similarly, the hyperlocomotion of low doses of DOM is reduced by the serotonin 5-HT2A receptor antagonist volinanserin (MDL-100907) and enhanced by the serotonin 5-HT2C receptor antagonist SB-242084 and its hypolocomotion at high doses is attenuated by SB-242084. As such, it has been concluded that serotonin 5-HT2A receptor activation increases locomotor activity while serotonin 5-HT2C receptor agonism decreases locomotor activity.
The locomotor effects of many other serotonergic psychedelics have also been studied and have often been similar to the preceding agents. However, in other cases, they have been different. The tryptamine psychedelics psilocin and 5-MeO-DMT produce profound hypolocomotion in mice and this is blocked by the serotonin 5-HT1A receptor antagonist WAY-100635 or by serotonin 5-HT1A receptor knockout but not by the serotonin 5-HT2C receptor antagonist SB-242084. 5-MeO-DALT dose-dependently increased locomotor activity but produced a sharp decrease at the highest tested dose. The relatively selective serotonin 5-HT2A receptor agonist 25I-NBOMe has been found to show similar locomotor effects to phenylalkylamine psychedelics, increasing locomotor activity at low doses at decreasing it at higher doses. The selective serotonin 5-HT2A receptor agonist 25CN-NBOH modestly increased locomotor activity or did not affect it.
The non-selective serotonin 5-HT2C receptor agonists meta-chlorophenylpiperazine (mCPP) and Ro60-0175 as well as the selective serotonin 5-HT2C receptor agonists WAY-161503 and CP-809101 produce hypolocomotion in rodents. In serotonin 5-HT2C receptor knockout mice, on the other hand, mCPP produced hyperlocomotion. In contrast to most serotonin 5-HT2C receptor agonists, the selective serotonin 5-HT2C receptor agonist WAY-163909 had no effect on spontaneous locomotor activity. The selective serotonin 5-HT2C receptor agonists WAY-163909 and CP-809101 have been found to suppress dextroamphetamine-induced hyperlocomotion. The non-selective serotonin 5-HT2C receptor agonist Ro60-0175 has been found to suppress the hyperlocomotion induced by cocaine, and this effect could be blocked by the selective serotonin 5-HT2C receptor antagonist SB-242084. CP-809101 has been found to decrease locomotor activity and antagonized phencyclidine (PCP)-induced hyperlocomotion.
Serotonin receptor antagonists
Serotonin 5-HT2A receptor antagonists like volinanserin (MDL-100907) and ketanserin counteract the hyperactivity induced by amphetamine, cocaine, and NMDA receptor antagonists like PCP in animals. Less-selective serotonin 5-HT2A receptor antagonists, like trazodone, have been found to decrease locomotor and behavioral activity and to inhibit amphetamine-, cocaine-, and PCP-induced hyperactivity in animals similarly. Blockade of the serotonin 5-HT2A receptor by atypical antipsychotics like clozapine and olanzapine contributes to the hypolocomotion they produce. In addition to serotonin 5-HT2A receptor antagonists, serotonin 5-HT2A receptor biased agonists that selectively activate the β-arrestin pathway but not the Gq pathway, like 25N-N1-Nap, have been found to antagonize PCP-induced locomotor hyperactivity in rodents.
Serotonin 5-HT2B receptor antagonists by themselves do not appear to affect locomotor activity. However, antagonists of the serotonin 5-HT2B receptor decrease the locomotor hyperactivity of amphetamine, cocaine, and phencyclidine (PCP).
The selective serotonin 5-HT2C receptor antagonist SB-242084 has been found to produce modest hyperlocomotion at high doses in rodents. The drug has also been found to produce modest stimulant-like effects in squirrel monkeys. SB-242084 has additionally been found to enhance the hyperlocomotion of dextroamphetamine in rodents. Similarly, it has been found to dose-dependently enhance the hyperlocomotion induced by dexfenfluramine in rodents. It has also been found to enhance the hyperlocomotion induced by MDMA, fenfluramine, cocaine, and methylphenidate, to modestly enhance nicotine- and morphine-induced hyperactivity, and to not affect the hyperactivity induced by RU-24969 or citalopram. The serotonin 5-HT2C receptor antagonist SB-221284 has been found to augment the nucleus accumbens dopamine elevations and hyperlocomotion induced by NMDA receptor antagonists like phencyclidine (PCP) and dizocilpine (MK-801) in rodents.
Glutamatergic agents
NMDA receptor antagonists
Hyperlocomotion is induced by NMDA receptor antagonists and dissociative hallucinogens such as phencyclidine (PCP), ketamine, and dizocilpine (MK-801). These drugs likewise induce stereotypies.
Cholinergic agents
Muscarinic acetylcholine receptor antagonists
Non-selective muscarinic acetylcholine receptor antagonists, or antimuscarinics, such as atropine, hyoscyamine, and scopolamine, produce robust hyperactivity in animals, but also produce deliriant effects such as amnesia and hallucinations in both animals and humans.
Cannabinoids
Tetrahydrocannabinol (THC) produces hypolocomotion in rodents. Cannabidiol (CBD) does not appear to affect locomotor activity when administered by itself or when added to THC. However, in some studies, CBD augmented THC-induced hypolocomotion.
Opioids
Classical opioids or μ-opioid receptor agonists like morphine and fentanyl stimulate locomotor activity in rodents. However, high doses of μ-opioid receptor agonists induce locomotor depression. δ-Opioid receptor agonists like AZD-2327 likewise stimulate locomotor activity in rodents.
TAAR1 modulators
The trace amine-associated receptor 1 (TAAR1) regulates the monoaminergic system and is a biological target for trace amines like β-phenethylamine and tyramine, the thyronamine 3-iodothyronamine, and drugs like amphetamines.
TAAR1 knockout mice show unchanged basal locomotor activity. However, they show enhanced hyperlocomotion with amphetamine, methamphetamine, and MDMA, as well as with β-phenethylamine. TAAR1 overexpression likewise is associated with unchanged basal locomotor activity. However, overexpression of the TAAR1 results in only weak locomotor stimulation by amphetamine. The TAAR1 full agonists RO5256390, ulotaront (SEP-363856), and LK00764 have been found to suppress locomotion in mice. Conversely, the TAAR1 full agonist RO5166017 and the TAAR1 partial agonists RO5073012, RO5203648, and RO5263397 on their own did not affect basal locomotion in rodents. Similarly, RO5263397 did not affect locomotor activity in monkeys. The TAAR1 antagonist EPPTB does not affect basal locomotor activity in rodents.
The TAAR1 full agonists RO5166017, RO5256390, and ulotaront all suppress psychostimulant-induced hyperlocomotion in mice. The TAAR1 partial agonists RO5073012, RO5203648, and RO5263397 suppress locomotor stimulation induced by cocaine. The TAAR1 partial agonist RO5203648 suppressed dextroamphetamine-induced hyperlocomotion at the highest assessed dose in rats but did not affect dextroamphetamine-induced hyperactivity in mice. It showed complex effects on methamphetamine-induced hyperlocomotion in rats, reducing early but potentiating late methamphetamine-induced hyperlocomotion with acute administration and suppressing methamphetamine-induced hyperlocomotion with chronic administration. The dual TAAR1 full agonist and serotonin 5-HT1 receptor modulator ulotaront did not affect dextroamphetamine-induced hyperlocomotion in rats. The TAAR1 weak partial agonist RO5073012 did not affect amphetamine-induced hyperlocomotion in mice but substantially restored the locomotor stimulation of amphetamine in mice with TAAR1 overexpression. In an unpublished study, EPPTB was reported to considerably reduce methamphetamine-induced hyperlocomotion in mice chronically exposed to methamphetamine, an effect that was absent in TAAR1 knockout mice. The TAAR1 full agonists RO5166017, RO5256390, ulotaront, and LK00764 and the TAAR1 partial agonists RO5203648 and RO5263397 suppress the hyperlocomotion induced by NMDA receptor antagonists like phencyclidine (PCP), L-687,414, and dizocilpine (MK-801) in rodents.
Other agents
Many tricyclic antidepressants (TCAs) do not increase locomotion, and instead often actually show behavioral sedation.
Non-drug stimuli affecting locomotor activity
Light exposure has been found to increase locomotor activity and exploratory behavior in rodents.
Similar behavioral measures
Other similar behavioral measures include stereotypy, exploratory behavior, climbing behavior, and jumping behavior. Amphetamines, which are dopamine releasing agents (DRAs) induce stereotypies in addition to hyperlocomotion. The dopamine receptor agonist apomorphine induces stereotypy and climbing behavior. The dopamine precursor levodopa (L-DOPA) induces jumping behavior. These effects can all be reversed by antipsychotics, which are dopamine receptor antagonists.
See also
Open field (animal test)
Conditioned avoidance response test
Animal models of schizophrenia
Dopamine hypothesis of schizophrenia
References
Animal testing techniques
Neuroscience of schizophrenia
Psychology experiments
Schizophrenia research
Symptoms and signs of mental disorders | Locomotor activity | [
"Chemistry"
] | 5,597 | [
"Animal testing",
"Animal testing techniques"
] |
56,227,543 | https://en.wikipedia.org/wiki/Abundisporus%20sclerosetosus | Abundisporus sclerosetosus is a species of bracket fungus in the family Polyporaceae that was described as new to science in 2000. It causes white rot on large decaying trunks of Shorea. A. sclerosetosus is found in the Bukit Timah Nature Reserve in Singapore. Fruit bodies of the fungus have light brown to dark reddish-brown caps with a cream to yellowish margin. Its spores are usually ellipsoid, markedly thick-walled, and measure 3.0–3.7 by 2.2–2.6 μm. A distinguishing microscopic characteristic of this fungus is the finger- or bristle-like hyphae in the trama of the tubes. The authors characterize the hyphal system as trimitic, but with reservations.
References
Polyporaceae
Fungi described in 2000
Fungi of Asia
Fungus species | Abundisporus sclerosetosus | [
"Biology"
] | 177 | [
"Fungi",
"Fungus species"
] |
56,228,047 | https://en.wikipedia.org/wiki/Plesiocystis | Plesiocystis is a genus of myxobacteria. It is a monotypic taxon containing only its type species, Plesiocystis pacifica. Both the genus and the species were first described in 2003, based on two strains isolated from samples collected from the Pacific coast of Japan.
Description
Cells of Plesiocystis species are straight, rod-shaped, and have blunt ends. They move by bacterial gliding and can form aggregates of cells known as fruiting bodies. They have distinctive cellular metabolism featuring, among other characteristics, partially saturated menaquinone (MK-8(H2)), polyunsaturated fatty acid production, and an absence of hydroxy fatty acids. Like typical myxobacteria, they have high GC content.
Taxonomy and history
The genus Plesiocystis was first described in 2003 on the basis of two strains of a single species, Plesiocystis pacifica, and remains a monotypic taxon. Originally placed in the suborder Soranginae, reclassification has since assigned this taxon to the suborder Nannocystineae. The genus name is derived from the Greek words plesion (neighbor) and cystis (bladder), noting the genus' relationship to another genus of myxobacteria, Nannocystis.
See also
List of bacterial orders
List of bacteria genera
References
Myxococcota
Bacteria genera | Plesiocystis | [
"Biology"
] | 295 | [
"Bacteria stubs",
"Bacteria"
] |
53,407,220 | https://en.wikipedia.org/wiki/LEXO | LEXO is the original version of the upgraded BURNOUT temperature regulating tumbler brand from manufacturer ThermAvant International, LLC, based in Columbia, Missouri.
History
The creator of LEXO, Hongbin "Bill" Ma, is a professor of mechanical and aerospace engineering and director of the Center for Thermal Management at the University of Missouri. After noticing how often he forgot coffee while waiting for it to cool, Ma began working on a “cup with constant temperature” in the summer of 2015. The LEXO was released to the general public in December 2016.
Design
The LEXO uses bio-based phase-change and advanced heat transfer materials to absorb the initial heat of the beverage and cool it to a more drinkable temperature. When the temperature begins to drop, the LEXO slowly releases the stored heat back into the drink. The LEXO can also insulate cold liquids.
The LEXO has three layers of 18/8 stainless-steel and BPA-free plastic lids.
References
External links
Drinkware
Physical chemistry | LEXO | [
"Physics",
"Chemistry"
] | 205 | [
"Physical chemistry",
"Applied and interdisciplinary physics",
"nan"
] |
53,409,225 | https://en.wikipedia.org/wiki/Copulation%20%28zoology%29 | In zoology, copulation is animal sexual behavior in which a male introduces sperm into the female's body, especially directly into her reproductive tract. This is an aspect of mating. Many aquatic animals use external fertilization, whereas internal fertilization may have developed from a need to maintain gametes in a liquid medium in the Late Ordovician epoch. Internal fertilization with many vertebrates (such as all reptiles, some fish, and most birds) occurs via cloacal copulation, known as cloacal kiss (see also hemipenis), while most mammals copulate vaginally, and many basal vertebrates reproduce sexually with external fertilization.
In spiders and insects
Spiders are often confused with insects, but they are not insects; instead, they are arachnids. Spiders have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on to it. He then stores the sperm in reservoirs on his large pedipalps, from which he transfers sperm to the female's genitals. The females can store sperm indefinitely.
For primitive insects, the male deposits spermatozoa on the substrate, sometimes stored within a special structure; courtship involves inducing the female to take up the sperm package into her genital opening, but there is no actual copulation. In groups that have reproduction similar to spiders, such as dragonflies, males extrude sperm into secondary copulatory structures removed from their genital opening, which are then used to inseminate the female. In dragonflies, it is a set of modified sternites on the second abdominal segment. In advanced groups of insects, the male uses its aedeagus, a structure formed from the terminal segments of the abdomen, to deposit sperm directly (though sometimes in a capsule called a spermatophore) into the female's reproductive tract.
In mammals
Sexual behavior can be classified into behavioral states associated with reward motivation ("wanting"), reward consummation also known as pleasure ("liking"), and satiety ("inhibition"); these behavioral states are regulated in mammals by reward-based sexual learning, fluctuations in various neurochemicals (i.e., dopamine − sexual desire also known as "wanting"; norepinephrine − sexual arousal; oxytocin and melanocortins − sexual attraction), and gonadal hormone cycles and further influenced by sex pheromones and motor reflexes (i.e., lordosis behaviour) in some mammals.
These behavioral states correlate with the phases of the human sexual response cycle: motivation − excitement; consummation − plateau and orgasm; satiety − refraction. Sexual learning (a form of associative learning) occurs when an animal starts to associate bodily features, personality, contextual cues, and other stimuli with genitally-induced sexual pleasure. Once formed, these associations in turn impinge upon both sexual wanting and sexual liking.
In most female mammals, the act of copulation is controlled by several innate neurobiological processes, including the motor sexual reflex of lordosis. In males, the act of copulation is more complex, because some learning is necessary, but the innate processes (retrocontrol of penis intromission in the vagina, rhythmic movement of the pelvis, detection of female pheromones) are specific to copulation. These innate processes direct heterosexual copulation. Female lordosis behaviour became secondary in Hominidae and is non-functional in humans. Mammals usually copulate in a dorso-ventral posture, although some primate species copulate in a ventro-vental posture.
Most mammals possess a vomeronasal organ that is involved in pheromone detection, including sex pheromones. Despite the fact that humans do not possess this organ, adult humans appear to be sensitive to certain mammalian pheromones that putative pheromone receptor proteins in the olfactory epithelium are capable of detecting. While sex pheromones clearly play a role in modifying sexual behavior in some mammals, the capacity for general pheromone detection and the involvement of pheromones in human sexual behavior has not yet been determined.
The duration of copulation varies significantly between mammal species, and may be correlated with body mass, lasting longer in large mammals than in small mammals. The duration of copulation may also be correlated with the length of the baculum in mammals.
Male mammals ejaculate semen through the penis into the female reproductive tract during copulation. Ejaculation usually occurs after only one intromission in humans, canids, and ungulates, but occurs after multiple intromissions in most mammal species.
Copulation can induce ovulation in mammal species that do not ovulate spontaneously.
See also
Pelvic thrust
Notes
References
Bibliography
Møller, A. P., and T. R. Birkhead. "Copulation behaviour in mammals: evidence that sperm competition is widespread." Biological Journal of the Linnean Society 38.2 (1989): 119–131.
Birkhead, Timothy R., L. Atkin, and A. P. Møller. "Copulation behaviour of birds." Behaviour 101.1 (1987): 101–138.
Carlson, Debra A. Reproductive biology of the coyote (Canis latrans): integration of behavior and physiology. Utah State University, 2008.
Castro, Ana Mafalda Lopes Sardica Velez. Mexican gray wolf courtship and mating: behavior & basic endocrinology during breeding season. Diss. Universidade de Lisboa. Faculdade de Medicina Veterinária, 2016.
Szykman, Micaela, et al. "Courtship and mating in free-living spotted hyenas." Behaviour 144.7 (2007): 815–846.
Dixson, Alan F. "Baculum length and copulatory behavior in primates." American Journal of Primatology 13.1 (1987): 51–60.
Animal physiology
Animal sexuality
Mammalian sexuality
Mating
Ethology | Copulation (zoology) | [
"Biology"
] | 1,280 | [
"Behavior",
"Animals",
"Animal physiology",
"Behavioural sciences",
"Animal sexuality",
"Ethology",
"Sexuality",
"Mating"
] |
53,412,666 | https://en.wikipedia.org/wiki/NGC%205003 | NGC 5003 is a spiral galaxy in the constellation Canes Venatici. The celestial object was discovered on April 9, 1787, by the German-British astronomer William Herschel.
References
5003
Spiral galaxies
Canes Venatici | NGC 5003 | [
"Astronomy"
] | 49 | [
"Canes Venatici",
"Constellations"
] |
53,412,768 | https://en.wikipedia.org/wiki/Vault%207 | Vault 7 is a series of documents that WikiLeaks began to publish on 7 March 2017, detailing the activities and capabilities of the United States Central Intelligence Agency (CIA) to perform electronic surveillance and cyber warfare. The files, dating from 2013 to 2016, include details on the agency's software capabilities, such as the ability to compromise cars, smart TVs, web browsers including Google Chrome, Microsoft Edge, Mozilla Firefox, and Opera, the operating systems of most smartphones including Apple's iOS and Google's Android, and computer operating systems including Microsoft Windows, macOS, and Linux. A CIA internal audit identified 91 malware tools out of more than 500 tools in use in 2016 being compromised by the release. The tools were developed by the Operations Support Branch of the CIA.
The Vault 7 release led the CIA to redefine WikiLeaks as a "non-state hostile intelligence service." In July 2022, former CIA software engineer Joshua Schulte was convicted of leaking the documents to WikiLeaks, and in February 2024 sentenced to 40 years' imprisonment, on espionage counts and separately to 80 months for child pornography counts.
History
In February 2017, WikiLeaks began teasing the release of "Vault 7" with a series of cryptic messages on Twitter, according to media reports. Later on in February, WikiLeaks released classified documents describing how the CIA monitored the 2012 French presidential election. The press release for the leak stated that it was published "as context for its forthcoming CIA Vault 7 series."
In March 2017, US intelligence and law enforcement officials said to the international wire agency Reuters that they had been aware of the CIA security breach which led to Vault 7 since late 2016. Two officials said they were focusing on "contractors" as the possible source of the leaks.
In 2017, federal law enforcement identified CIA software engineer Joshua Adam Schulte as a suspected source of Vault 7. Schulte plead not guilty and was convicted in July 2022 of leaking the documents to WikiLeaks.
On 13 April 2017, CIA director Mike Pompeo declared WikiLeaks to be a "hostile intelligence service." In September 2021, Yahoo! News reported that in 2017 in the wake of the Vault 7 leaks, the CIA considered kidnapping or assassinating Julian Assange, the founder of WikiLeaks. The CIA also considered spying on associates of WikiLeaks, sowing discord among its members, and stealing their electronic devices. After many months of deliberation, all proposed plans had been scrapped due to a combination of legal and moral objections. Per the 2021 Yahoo News article, a former Trump national security official stated, "We should never act out of a desire for revenge".
The Vault 7 release led the CIA to redefine WikiLeaks as a "non-state hostile intelligence service." In July 2022, former CIA software engineer Joshua Schulte was convicted of leaking the documents to WikiLeaks, and in February 2024 sentenced to 40 years' imprisonment.
Publications
Part 1 – "Year Zero"
The first batch of documents named "Year Zero" was published by WikiLeaks on 7 March 2017, consisting of 7,818 web pages with 943 attachments, purportedly from the Center for Cyber Intelligence, which contained more pages than former NSA contractor and leaker, Edward Snowden's NSA release at the time. WikiLeaks had released Year Zero online in a locked archive earlier that week, and revealing the passphrase on the 7th. The passphrase referred to a President Kennedy quote that he wanted “to splinter the CIA in a thousand pieces and scatter it to the winds”.
WikiLeaks did not name the source, but said that the files had "circulated among former U.S. government hackers and contractors in an unauthorized manner, one of whom has provided WikiLeaks with portions of the archive." According to WikiLeaks, the source "wishes to initiate a public debate about the security, creation, use, proliferation and democratic control of cyberweapons" since these tools raise questions that "urgently need to be debated in public, including whether the C.I.A.'s hacking capabilities exceed its mandated powers and the problem of public oversight of the agency."
WikiLeaks attempted to redact names and other identifying information from the documents before their release, but faced criticism for leaving some key details unredacted. WikiLeaks also attempted to allow for connections between people to be drawn via unique identifiers generated by WikiLeaks. It also said that it would postpone releasing the source code for the cyber weapons, which is reportedly several hundred million lines long, "until a consensus emerges on the technical and political nature of the C.I.A.'s program and how such 'weapons' should be analyzed, disarmed and published." WikiLeaks founder Julian Assange claimed this was only part of a larger series.
The CIA released a statement saying, "The American public should be deeply troubled by any WikiLeaks disclosure designed to damage the Intelligence Community's ability to protect America against terrorists or other adversaries. Such disclosures not only jeopardize US personnel and operations, but also equip our adversaries with tools and information to do us harm."
In a statement issued on 19 March 2017, Assange said the technology companies who had been contacted had not agreed to, disagreed with, or questioned what he termed as WikiLeaks' standard industry disclosure plan. The standard disclosure time for a vulnerability is 90 days after the company responsible for patching the software is given full details of the flaw. According to WikiLeaks, only Mozilla had been provided with information on the vulnerabilities, while "Google and some other companies" only confirmed receiving the initial notification. WikiLeaks stated: "Most of these lagging companies have conflicts of interest due to their classified work with US government agencies. In practice such associations limit industry staff with US security clearances from fixing holes based on leaked information from the CIA. Should such companies choose to not secure their users against CIA or NSA attacks users may prefer organizations such as Mozilla or European companies that prioritize their users over government contracts".
Part 2 – "Dark Matter"
On 23 March 2017 WikiLeaks published the second release of Vault 7 material, entitled "Dark Matter". The publication included documentation for several CIA efforts to hack Apple's iPhones and Macs. These included the Sonic Screwdriver malware that could use the Thunderbolt interface to bypass Apple's password firmware protection.
Part 3 – "Marble"
On 31 March 2017, WikiLeaks published the third part, "Marble". It contained 676 source code files for the CIA's Marble Framework. It is used to obfuscate, or scramble, malware code in an attempt to make it so that anti-virus firms or investigators cannot understand the code or attribute its source. According to WikiLeaks, the code also included a de-obfuscator to reverse the obfuscation effects.
Part 4 – "Grasshopper"
On 7 April 2017, WikiLeaks published the fourth set, "Grasshopper". The publication contains 27 documents from the CIA's Grasshopper framework, which is used by the CIA to build customized and persistent malware payloads for the Microsoft Windows operating systems. Grasshopper focused on Personal Security Product (PSP) avoidance. PSPs are antivirus software such as MS Security Essentials, Symantec Endpoint or Kaspersky IS.
Part 5 – "HIVE"
On 14 April 2017, WikiLeaks published the fifth part, "HIVE". Based on the CIA top-secret virus program created by its "Embedded Development Branch" (EDB). The six documents published by WikiLeaks are related to the HIVE multi-platform CIA malware suite. A CIA back-end infrastructure with a public-facing HTTPS interface used by CIA to transfer information from target desktop computers and smartphones to the CIA, and open those devices to receive further commands from CIA operators to execute specific tasks, all the while hiding its presence behind unsuspicious-looking public domains through a masking interface known as "Switchblade" (also known as Listening Post (LP) and Command and Control (C2)).
Part 6 – "Weeping Angel"
On 21 April 2017, WikiLeaks published the sixth part, "Weeping Angel" (named for a monster in the TV show Doctor Who), a hacking tool co-developed by the CIA and MI5 used to exploit a series of early smart TVs for the purpose of covert intelligence gathering. Once installed in suitable televisions with a USB stick, the hacking tool enables those televisions' built-in microphones and possibly video cameras to record their surroundings, while the televisions falsely appear to be turned off. The recorded data is then either stored locally into the television's memory or sent over the internet to the CIA. Allegedly both the CIA and MI5 agencies collaborated to develop that malware in Joint Development Workshops. Security expert Sarah Zatko said about the data "nothing in this suggests it would be used for mass surveillance," and Consumer Reports said that only some of the earliest smart TVs with built-in microphones and cameras were affected.
Part 7 – "Scribbles"
On 28 April 2017, WikiLeaks published the seventh part, "Scribbles". The leak includes documentation and source code of a tool intended to track documents leaked to whistleblowers and journalists by embedding web beacon tags into classified documents to trace who leaked them. The tool affects Microsoft Office documents, specifically "Microsoft Office 2013 (on Windows 8.1 x64), documents from Office versions 97-2016 (Office 95 documents will not work) and documents that are not locked, encrypted, or password-protected". When a CIA watermarked document is opened, an invisible image within the document that is hosted on the agency's server is loaded, generating a HTTP request. The request is then logged on the server, giving the intelligence agency information about who is opening it and where it is being opened. However, if a watermarked document is opened in an alternative word processor the image may be visible to the viewer. The documentation also states that if the document is viewed offline or in protected view, the watermarked image will not be able to contact its home server. This is overridden only when a user enables editing.
Part 8 – "Archimedes"
On 5 May 2017, WikiLeaks published the eighth part, "Archimedes". According to U.S. SANS Institute instructor Jake Williams, who analyzed the published documents, Archimedes is a virus previously codenamed "Fulcrum". According to cyber security expert and ENISA member Pierluigi Paganini, the CIA operators use Archimedes to redirect local area network (LAN) web browser sessions from a targeted computer through a computer controlled by the CIA before the sessions are routed to the users. This type of attack is known as man-in-the-middle (MitM). With their publication WikiLeaks included a number of hashes that they claim can be used to potentially identify the Archimedes virus and guard against it in the future. Paganini stated that potential targeted computers can search for those hashes on their systems to check if their systems had been attacked by the CIA.
Part 9 – "AfterMidnight" and "Assassin"
On 12 May 2017, WikiLeaks published part nine, "AfterMidnight" and "Assassin". AfterMidnight is a piece of malware installed on a target personal computer and disguises as a DLL file, which is executed while the user's computer reboots. It then triggers a connection to the CIA's Command and Control (C2) computer, from which it downloads various modules to run. As for Assassin, it is very similar to its AfterMidnight counterpart, but deceptively runs inside a Windows service process. CIA operators reportedly use Assassin as a C2 to execute a series of tasks, collect, and then periodically send user data to the CIA Listening Post(s) (LP). Similar to backdoor Trojan behavior. Both AfterMidnight and Assassin run on Windows operating system, are persistent, and periodically beacon to their configured LP to either request tasks or send private information to the CIA, as well as automatically uninstall themselves on a set date and time.
Part 10 – "Athena"
On 19 May 2017, WikiLeaks published the tenth part, "Athena". The published user guide, demo, and related documents were created between September 2015 and February 2016. They are about a malware allegedly developed for the CIA in August 2015, about a month after Microsoft released Windows 10 with their firm statements about how difficult it was to compromise. Both the primary "Athena" malware and its secondary malware named "Hera" are similar in theory to Grasshopper and AfterMidnight malware but with some significant differences. One of those differences is that Athena and Hera were developed by the CIA with a New Hampshire private corporation called Siege Technologies. During a Bloomberg 2014 interview the founder of Siege Technologies confirmed and justified their development of such malware. Athena malware completely hijacks Windows' Remote Access services, while Hera hijacks Windows Dnscache service. Both Athena and Hera also affect all then current versions of Windows including Windows Server 2012 and Windows 10. Another difference is in the types of encryption used between the infected computers and the CIA Listening Posts (LP). As for the similarities, they exploit persistent DLL files to create a backdoor to communicate with CIA's LP, steal private data, then send it to CIA servers, or delete private data on the target computer, as well as Command and Control (C2) for CIA operatives to send additional malicious software to further run specific tasks on the attacked computer. All of the above designed to deceive computer security software. Beside the published detailed documents, WikiLeaks did not provide any evidence suggesting the CIA used Athena or not.
Part 11 – "Pandemic"
On 1 June 2017, WikiLeaks published part 11, "Pandemic". This tool is a persistent implant affecting Windows machines with shared folders. It functions as a file system filter driver on an infected computer, and listens for Server Message Block traffic while detecting download attempts from other computers on a local network. "Pandemic" will answer a download request on behalf of the infected computer. However, it will replace the legitimate file with malware. In order to obfuscate its activities, "Pandemic" only modifies or replaces the legitimate file in transit, leaving the original on the server unchanged. The implant allows 20 files to be modified at a time, with a maximum individual file size of 800MB. While not stated in the leaked documentation, it is possible that newly infected computers could themselves become "Pandemic" file servers, allowing the implant to reach new targets on a local network.
Part 12 – "Cherry Blossom"
On 15 June 2017, WikiLeaks published part 12, entitled "Cherry Blossom". Cherry Blossom used a command and control server called Cherry Tree and custom router firmware called FlyTrap to monitor internet activity of targets, scan for “email addresses, chat usernames, MAC addresses and VoIP numbers" and redirect traffic.
Part 13 – "Brutal Kangaroo"
On 22 June 2017, WikiLeaks published part 13, the manuals for "Brutal Kangaroo". Brutal Kangaroo was a project focused on CIA malware designed to compromise air-gapped computer networks with infected USB drives. Brutal Kangaroo included the tools Drifting Deadline, the main tool, Shattered Assurance, a server that automates thumb drive infection, Shadow, a tool to coordinate compromised machines, and Broken Promise, a tool for exfiltrating data from the air-gapped networks.
Part 14 – "Elsa"
On 28 June 2017, WikiLeaks published part 14, the manual for the project entitled "Elsa". Elsa was a tool used for tracking Windows devices on nearby WiFi networks.
Part 15 – "OutlawCountry"
On 29 June 2017, WikiLeaks published part 15, the manual for project "OutlawCountry". OutlawCountry was a kernel module for Linux 2.6 that let CIA agents spy on Linux servers and redirect outgoing traffic from a Linux computer to a chosen site.
Part 16 – "BothanSpy"
On 6 July 2017, WikiLeaks published part 16, the manual for project "BothanSpy". BothanSpy was a CIA hacking tool made to steal SSH credentials from Windows computers.
Part 17 – "Highrise"
On 13 July 2017, WikiLeaks published part 17, the manual for project "Highrise". The Highrise hacking tool, also known as Tidecheck, was used to intercept and redirect SMS messages to Android phones using versions 4.0 through 4.3. Highrise could also be used as an encrypted communications channel between CIA agents and supervisors.
Part 18 – "UCL / Raytheon"
On 19 July 2017, WikiLeaks published part 18, documents from Raytheon Blackbird Technologies for the "UMBRAGE Component Library" (UCL) project reports on malware and their attack vectors. According to WikiLeaks, it analysed malware attacks in the wild and gave "recommendations to the CIA development teams for further investigation and PoC development for their own malware projects." It mostly contained Proof-of-Concept ideas partly based on public documents.
Part 19 – "Imperial"
On 27 July 2017, WikiLeaks published part 19, manuals for project "Imperial". Imperial included three tools: Achilles, Aeris and SeaPea. Achilles turned MacOS DMG install files into trojan malware. Aeris was a malware implant for POSIX systems, and SeaPea was an OS X rootkit.
Part 20 – "Dumbo"
On 3 August 2017, WikiLeaks published part 20, manuals for project "Dumbo". Dumbo was a tool that the Agency used to disable webcams, microphones, and other surveillance tools over WiFi and bluetooth to allow field agents to perform their missions.
Part 21 – "CouchPotato"
On 10 August 2017, WikiLeaks published part 21, the manual for project CouchPotato. CouchPotato was a tool for intercepting and saving remote video streams, which let the CIA tap into other people's surveillance systems.
Part 22 – "ExpressLane"
On 24 August 2017, WikiLeaks published part 22, the "ExpressLane" project. These documents highlighted one of the cyber operations the CIA conducts against other services it liaises with, including the National Security Agency (NSA), the Department of Homeland Security (DHS) and the Federal Bureau of Investigation (FBI).
ExpressLane, a covert information collection tool, was used by the CIA to exfiltrate the biometric data collection systems of services it liaises with. ExpressLane was installed and run under the cover of upgrading the biometric software of liaison services by the CIA's Office of Technical Services (OTS) agents without their knowledge.
Part 23 – "Angelfire"
On 31 August 2017, WikiLeaks published part 23, the manual for the project Angelfire. Angelfire was a malware framework made to infect computers running Windows XP and Windows 7, made of five parts. Solartime was the malware that modified the boot sector to load Wolfcreek, which was a self-loading driver that loaded other drivers. Keystone was responsible for loading other malware. BadMFS was a covert file system that hid the malware, and Windows Transitory File System was a newer alternative to BadMFS. The manual included a long list of problems with the tools.
Part 24 – "Protego"
Protego, part 24 of the Vault 7 documents, was published on 7 September 2017. According to WikiLeaks, Protego "is a PIC-based missile control system that was developed by Raytheon."
Vault 8
On 9 November 2017, WikiLeaks began publishing Vault 8, which it described as "source code and analysis for CIA software projects including those described in the Vault7 series." The stated intention of the Vault 8 publication was to "enable investigative journalists, forensic experts and the general public to better identify and understand covert CIA infrastructure components." The only Vault 8 release has been the source code and development logs for Hive, a covert communications platform for CIA malware. WikiLeaks published the Hive documentation as part of Vault 7 on 14 April 2017.
In October 2021, a new backdoor based on the Hive source code was discovered being used "to collect sensitive information and provide a foothold for subsequent intrusions." Researchers called it xdr33 and released a report on it in January 2022. The malware targets an unspecified F5 appliance and allowed hackers to upload and download files. It also allowed network traffic spying and execute commands on the appliance.
Organization of cyber warfare
WikiLeaks said that the documents came from "an isolated, high-security network situated inside the CIA's Center for Cyber Intelligence (CCI) in Langley, Virginia." The documents allowed WikiLeaks to partially determine the structure and organization of the CCI. The CCI reportedly has a unit devoted to compromising Apple products.
The cybersecurity firm Symantec analyzed Vault 7 documents and found some of the described software closely matched cyberattacks by "Longhorn," which it had monitored since 2014. Symantec had previously suspected that "Longhorn" was government-sponsored and had tracked its usage against 40 targets in 16 countries.
Frankfurt base
The first portion of the documents made public on 7 March 2017, Vault 7 "Year Zero", revealed that a top secret CIA unit used the German city of Frankfurt as the starting point for hacking attacks on Europe, China and the Middle East. According to the documents, the U.S. government uses its Consulate General Office in Frankfurt as a hacker base for cyber operations. WikiLeaks documents reveal the Frankfurt hackers, part of the Center for Cyber Intelligence Europe (CCIE), were given cover identities and diplomatic passports to obfuscate customs officers to gain entry to Germany.
The chief Public Prosecutor General of the Federal Court of Justice in Karlsruhe Peter Frank announced on 8 March 2017 that the government was conducting a preliminary investigation to see if it will launch a major probe into the activities being conducted out of the consulate and also more broadly whether people in Germany were being attacked by the CIA. Germany's foreign minister Sigmar Gabriel from the Social Democratic Party responded to the documents of Vault 7 "Year Zero" that the CIA used Frankfurt as a base for its digital espionage operations, saying that Germany did not have any information about the cyber attacks.
UMBRAGE
The documents reportedly revealed that the agency had amassed a large collection of cyberattack techniques and malware produced by other hackers. This library was reportedly maintained by the CIA's Remote Devices Branch's UMBRAGE group, with examples of using these techniques and source code contained in the "Umbrage Component Library" git repository.
False flag conspiracy theories
On the day the Vault 7 documents were first released, WikiLeaks described UMBRAGE as "a substantial library of attack techniques 'stolen' from malware produced in other states including the Russian Federation," and tweeted, "CIA steals other groups virus and malware facilitating false flag attacks." According to WikiLeaks, by recycling the techniques of third parties through UMBRAGE, the CIA can not only increase its total number of attacks, but can also mislead forensic investigators by disguising these attacks as the work of other groups and nations. Among the techniques borrowed by UMBRAGE was the file wiping implementation used by Shamoon. According to PC World, some of the techniques and code snippets have been used by CIA in its internal projects, whose result cannot be inferred from the leaks. PC World commented that the practice of planting "false flags" to deter attribution was not a new development in cyberattacks: Russian, North Korean and Israeli hacker groups are among those suspected of using false flags.
A conspiracy theory soon emerged alleging that the CIA framed the Russian government for interfering in the 2016 U.S. elections. Conservative commentators such as Sean Hannity and Ann Coulter speculated about this possibility on Twitter, and Rush Limbaugh discussed it on his radio show. Russian foreign minister Sergey Lavrov said that Vault 7 showed that "the CIA could get access to such 'fingerprints' and then use them."
Cybersecurity writers and experts, such as Ben Buchanan and Kevin Poulsen, were skeptical of those theories. Poulsen said the theories were "disinformation" being taken advantage of by Russia and spread by bots. He also wrote, "The leaked catalog isn't organized by country of origin, and the specific malware used by the Russian DNC hackers is nowhere on the list." Robert M. Lee, who founded the cybersecurity firm Dragos, said the "narrative emerged far too quickly to have been organic."
According to a study by Kim Zetter in The Intercept, UMBRAGE was probably much more focused on speeding up development by repurposing existing tools, rather than on planting false flags. Robert Graham, CEO of Errata Security told The Intercept that the source code referenced in the UMBRAGE documents is "extremely public", and is likely used by a multitude of groups and state actors. Graham added: "What we can conclusively say from the evidence in the documents is that they're creating snippets of code for use in other projects and they're reusing methods in code that they find on the internet. ... Elsewhere they talk about obscuring attacks so you can't see where it's coming from, but there's no concrete plan to do a false flag operation. They're not trying to say 'We're going to make this look like Russia'."
Marble framework
The documents describe the Marble framework, a string obfuscator used to hide text fragments in malware from visual inspection. Some outlets reported that foreign languages were used to cover up the source of CIA hacks, but technical analysis refuted the idea. According to WikiLeaks, it reached 1.0 in 2015 and was used by the CIA throughout 2016.
In its release, WikiLeaks said "Marble" was used to insert foreign language text into the malware to mask viruses, trojans and hacking attacks, making it more difficult for them to be tracked to the CIA and to cause forensic investigators to falsely attribute code to the wrong nation. The source code revealed that Marble had examples in Chinese, Russian, Korean, Arabic and Persian.
Analysts called WikiLeaks' description of Marble's main purpose inaccurate, telling The Hill its main purpose was probably to avoid detection by antivirus programs.
Marble also contained a deobfuscator tool with which the CIA could reverse text obfuscation.
Security researcher Nicholas Weaver from International Computer Science Institute in Berkeley told the Washington Post: "This appears to be one of the most technically damaging leaks ever done by WikiLeaks, as it seems designed to directly disrupt ongoing CIA operations."
Compromised technology and software
CDs/DVDs
HammerDrill is a CD/DVD collection tool that collects directory walks and files to a configured directory and filename pattern as well as logging CD/DVD insertion and removal events.
Apple products
After WikiLeaks released the first installment of Vault 7, "Year Zero", Apple stated that "many of the issues leaked today were already patched in the latest iOS," and that the company will "continue work to rapidly address any identified vulnerabilities."
On 23 March 2017, WikiLeaks released "Dark Matter", the second batch of documents in its Vault 7 series, detailing the hacking techniques and tools all focusing on Apple products developed by the Embedded Development Branch (EDB) of the CIA. The leak also revealed the CIA had been targeting the iPhone since 2008, and that some projects attacked Apple's firmware. The "Dark Matter" archive included documents from 2009 and 2013. Apple issued a second statement assuring that based on an "initial analysis, the alleged iPhone vulnerability affected iPhone 3G only and was fixed in 2009 when iPhone 3GS was released." Additionally, a preliminary assessment showed "the alleged Mac vulnerabilities were previously fixed in all Macs launched after 2013".
Cisco
WikiLeaks said on 19 March 2017 on Twitter that the "CIA was secretly exploiting" a vulnerability in a huge range of Cisco router models discovered thanks to the Vault 7 documents. The CIA had learned more than a year ago how to exploit flaws in Cisco's widely used internet switches, which direct electronic traffic, to enable eavesdropping. Cisco quickly reassigned staff from other projects to turn their focus solely on analyzing the attack and to figure out how the CIA hacking worked, so they could help customers patch their systems and prevent criminal hackers or spies from using similar methods.
On 20 March, Cisco researchers confirmed that their study of the Vault 7 documents showed the CIA had developed malware which could exploit a flaw found in 318 of Cisco's switch models and alter or take control of the network. Cisco issued a warning on security risks, patches were not available, but Cisco provided mitigation advice.
Smartphones/tablets
The electronic tools can reportedly compromise both Apple's iOS and Google's Android operating systems. By adding malware to the Android operating system, the tools could gain access to secure communications made on a device.
Messaging services
According to WikiLeaks, once an Android smartphone is penetrated the agency can collect "audio and message traffic before encryption is applied". Some of the agency's software is reportedly able to gain access to messages sent by instant messaging services. This method of accessing messages differs from obtaining access by decrypting an already encrypted message. While the encryption of messengers that offer end-to-end encryption, such as Telegram, WhatsApp and Signal, wasn't reported to be cracked, their encryption can be bypassed by capturing input before their encryption is applied, by methods such as keylogging and recording the touch input from the user.
Commentators, including Snowden and cryptographer and security pundit Bruce Schneier, observed that Wikileaks incorrectly implied that the messaging apps themselves, and their underlying encryption, had been compromised - an implication which was in turn reported for a period by the New York Times and other mainstream outlets.
Vehicle control systems
One document reportedly showed that the CIA was researching ways to infect vehicle control systems. WikiLeaks stated, "The purpose of such control is not specified, but it would permit the CIA to engage in nearly undetectable assassinations." This statement brought renewed attention to conspiracy theories surrounding the death of Michael Hastings.
Windows
The documents refer to a "Windows FAX DLL injection" exploit in Windows XP, Windows Vista and Windows 7 operating systems. This would allow a user with malicious intent to hide malware under the DLL of another application. However, a computer must have already been compromised through another method for the injection to take place.
Commentary
On 7 March 2017, Edward Snowden commented on the importance of the release, stating that it reveals the United States Government to be "developing vulnerabilities in US products" and "then intentionally keeping the holes open", which he considered highly reckless. On 7 March 2017, Nathan White, Senior Legislative Manager at the Internet advocacy group Access Now, wrote:
On 8 March 2017, Lee Mathews, a contributor to Forbes, wrote that most of the hacking techniques described in Vault 7 were already known to many cybersecurity experts. On 8 March 2017, some noted that the revealed techniques and tools are most likely to be used for more targeted surveillance revealed by Edward Snowden.
On 8 April 2017, Ashley Gorski, an American Civil Liberties Union staff attorney called it "critical" to understand that "these vulnerabilities can be exploited not just by our government but by foreign governments and cyber criminals around the world." Justin Cappos, professor in the Computer Science and Engineering department at New York University asks "if the government knows of a problem in your phone that bad guys could use to hack your phone and have the ability to spy on you, is that a weakness that they themselves should use for counterterrorism, or for their own spying capabilities, or is it a problem they should fix for everyone?"
On 8 April 2017, Cindy Cohn, executive director of the San Francisco-based international non-profit digital rights group Electronic Frontier Foundation, said: "If the C.I.A. was walking past your front door and saw that your lock was broken, they should at least tell you and maybe even help you get it fixed." "And worse, they then lost track of the information they had kept from you so that now criminals and hostile foreign governments know about your broken lock." Furthermore, she stated that the CIA had "failed to accurately assess the risk of not disclosing vulnerabilities. Even spy agencies like the CIA have a responsibility to protect the security and privacy of Americans." "The freedom to have a private conversation – free from the worry that a hostile government, a rogue government agent or a competitor or a criminal are listening – is central to a free society". The Fourth Amendment to the US constitution guarantees freedom from unreasonable search and seizure.
On 12 May 2017 Microsoft President, Brad Smith, wrote that both NSA and CIA had stockpiled vulnerabilities, which were stolen from them and published on Wikileaks, resulting in security breaches for Microsoft customers. Smith requested, for a second time, a "digital Geneva Convention" which would require governments to report vulnerabilities to vendors.
See also
References
External links
Vault 7 at WikiLeaks
Vault 8 at WikiLeaks
Julian Assange Press Conference and Q&A on CIA/Vault7/YearZero, Thursday 9 March 2017, the official WikiLeaks YouTube channel
2017 in the United States
2017 documents
Central Intelligence Agency domestic surveillance operations
Central Intelligence Agency controversies
Computer surveillance
Cyberwarfare
Hacking in the 2010s
Information published by WikiLeaks
Instant messaging
March 2017 events in the United States
Computer security exploits
Works about security and surveillance | Vault 7 | [
"Technology"
] | 7,185 | [
"Instant messaging",
"Computer security exploits"
] |
53,413,131 | https://en.wikipedia.org/wiki/Planigon | In geometry, a planigon is a convex polygon that can fill the plane with only copies of itself (isotopic to the fundamental units of monohedral tessellations). In the Euclidean plane there are 3 regular planigons; equilateral triangle, squares, and regular hexagons; and 8 semiregular planigons; and 4 demiregular planigons which can tile the plane only with other planigons.
All angles of a planigon are whole divisors of 360°. Tilings are made by edge-to-edge connections by perpendicular bisectors of the edges of the original uniform lattice, or centroids along common edges (they coincide).
Tilings made from planigons can be seen as dual tilings to the regular, semiregular, and demiregular tilings of the plane by regular polygons.
History
In the 1987 book, Tilings and patterns, Branko Grünbaum calls the vertex-uniform tilings Archimedean in parallel to the Archimedean solids. Their dual tilings are called Laves tilings in honor of crystallographer Fritz Laves. They're also called Shubnikov–Laves tilings after Shubnikov, Alekseĭ Vasilʹevich. John Conway calls the uniform duals Catalan tilings, in parallel to the Catalan solid polyhedra.
The Laves tilings have vertices at the centers of the regular polygons, and edges connecting centers of regular polygons that share an edge. The tiles of the Laves tilings are called planigons. This includes the 3 regular tiles (triangle, square and hexagon) and 8 irregular ones. Each vertex has edges evenly spaced around it. Three dimensional analogues of the planigons are called stereohedrons.
These tilings are listed by their face configuration, the number of faces at each vertex of a face. For example V4.8.8 (or V4.82) means isosceles triangle tiles with one corner with four triangles, and two corners containing eight triangles.
Construction
The Conway operation of dual interchanges faces and vertices. In Archimedean solids and k-uniform tilings alike, the new vertex coincides with the center of each regular face, or the centroid. In the Euclidean (plane) case; in order to make new faces around each original vertex, the centroids must be connected by new edges, each of which must intersect exactly one of the original edges. Since regular polygons have dihedral symmetry, we see that these new centroid-centroid edges must be perpendicular bisectors of the common original edges (e.g. the centroid lies on all edge perpendicular bisectors of a regular polygon). Thus, the edges of k-dual uniform tilings coincide with centroid-to-edge-midpoint line segments of all regular polygons in the k-uniform tilings.
Using the 12-5 Dodecagram (Above)
All 14 uniform usable regular vertex planigons also hail from the 6-5 dodecagram (where each segment subtends radians, or 150 degrees).
The incircle of this dodecagram demonstrates that all the 14 VRPs are cocyclic, as alternatively shown by circle packings. The ratio of the incircle to the circumcircle is:
and the convex hull is precisely the regular dodecagons in the k-uniform tiling. The equilateral triangle, square, regular hexagon, and regular dodecagon; are shown above with the VRPs.
In fact, any group of planigons can be constructed from the edges of a polygram, where and is the number of sides of sides in the RP adjacent to each involved vertex figure. This is because the circumradius of any regular -gon (from the vertex to the centroid) is the same as the distance from the center of the polygram to its line segments which intersect at the angle , since all polygrams admit incircles of inradii tangent to all its sides.
Regular Vertices
In Tilings and Patterns, Grünbaum also constructed the Laves tilings using monohedral tiles with regular vertices. A vertex is regular if all angles emanating from it are equal. In other words:
All vertices are regular,
All Laves planigons are congruent.
In this way, all Laves tilings are unique except for the square tiling (1 degree of freedom), barn pentagonal tiling (1 degree of freedom), and hexagonal tiling (2 degrees of freedom):
When applied to higher dual co-uniform tilings, all dual coregular planigons can be distorted except for the triangles (AAA similarity), with examples below:
Derivation of all possible planigons
For edge-to-edge Euclidean tilings, the interior angles of the convex polygons meeting at a vertex must add to 360 degrees. A regular -gon has internal angle degrees. There are seventeen combinations of regular polygons whose internal angles add up to 360 degrees, each being referred to as a species of vertex; in four cases there are two distinct cyclic orders of the polygons, yielding twenty-one types of vertex.
In fact, with the vertex (interior) angles , we can find all combinations of admissible corner angles according to the following rules:
Every vertex has at least degree 3 (a degree-2 vertex must have two straight angles or one reflex angle);
If the vertex has degree , the smallest polygon vertex angles sum to over ;
The vertex angles add to , and must be angles of regular polygons of positive integer sides (of the sequence ).
Using the rules generates the list below:
*The cannot coexist with any other vertex types.
The solution to Challenge Problem 9.46, Geometry (Rusczyk), is in the Degree 3 Vertex column above. A triangle with a hendecagon (11-gon) yields a 13.2-gon, a square with a heptagon (7-gon) yields a 9.3333-gon, and a pentagon with a hexagon yields a 7.5-gon). Hence there are combinations of regular polygons which meet at a vertex.
Planigons in the plane
Only eleven of these angle combinations can occur in a Laves Tiling of planigons.
In particular, if three polygons meet at a vertex and one has an odd number of sides, the other two polygons must be the same. If they are not, they would have to alternate around the first polygon, which is impossible if its number of sides is odd. By that restriction these six cannot appear in any tiling of regular polygons:
On the other hand, these four can be used in k-dual-uniform tilings:
Finally, assuming unit side length, all regular polygons and usable planigons have side-lengths and areas as shown below in the table:
Number of Dual Uniform Tilings
Every dual uniform tiling is in a 1:1 correspondence with the corresponding uniform tiling, by construction of the planigons above and superimposition.
Such periodic tilings may be classified by the number of orbits of vertices, edges and tiles. If there are k orbits of planigons, a tiling is known as k-dual-uniform or k-isohedral; if there are t orbits of dual vertices, as t-isogonal; if there are e orbits of edges, as e-isotoxal.
k-dual-uniform tilings with the same vertex faces can be further identified by their wallpaper group symmetry, which is identical to that of the corresponding k-uniform tiling.
1-dual-uniform tilings include 3 regular tilings, and 8 Laves tilings, with 2 or more types of regular degree vertices. There are 20 2-dual-uniform tilings, 61 3-dual-uniform tilings, 151 4-dual-uniform tilings, 332 5-dual-uniform tilings and 673 6--dualuniform tilings. Each can be grouped by the number m of distinct vertex figures, which are also called m-Archimedean tilings.
Finally, if the number of types of planigons is the same as the uniformity (m = k below), then the tiling is said to be dual Krotenheerdt. In general, the uniformity is greater than or equal to the number of types of vertices (m ≥ k), as different types of planigons necessarily have different orbits, but not vice versa. Setting m = n = k, there are 11 such dual tilings for n = 1; 20 such dual tilings for n = 2; 39 such dual tilings for n = 3; 33 such dual tilings for n = 4; 15 such dual tilings for n = 5; 10 such dual tilings for n = 6; and 7 such dual tilings for n = 7.
Regular and Laves tilings
The 3 regular and 8 semiregular Laves tilings are shown, with planigons colored according to area as in the construction:
Higher Dual Uniform Tilings
Insets of Dual Planigons into Higher Degree Vertices
A degree-six vertex can be replaced by a center regular hexagon and six edges emanating thereof;
A degree-twelve vertex can be replaced by six deltoids (a center deltoidal hexagon) and twelve edges emanating thereof;
A degree-twelve vertex can be replaced by six Cairo pentagons, a center hexagon, and twelve edges emanating thereof (by dissecting the degree-6 vertex in the center of the previous example).
This is done above for the dual of the 3-4-6-12 tiling. The corresponding uniform process is dissection, and is shown here.
2-Dual-Uniform
There are 20 tilings made from 2 types of planigons, the dual of 2-uniform tilings (Krotenheerdt Duals):
3-Dual-Uniform
There are 39 tilings made from 3 types of planigons (Krotenheerdt Duals):
4-Dual-Uniform
There are 33 tilings made from 4 types of planigons (Krotenheerdt Duals):
5-Dual-Uniform
There are 15 5-uniform dual tilings with 5 unique planigons:
Krotenheerdt duals with six planigons
There are 10 6-uniform dual tilings with 6 unique planigons:
Krotenheerdt duals with seven planigons
There are 7 7-uniform dual tilings with 7 unique planigons:
The last two dual uniform-7 tilings have the same vertex types, even though they look nothing alike!
From onward, there are no uniform n tilings with n vertex types, or no uniform n duals with n distinct (semi)planigons.
Fractalizing Dual k-Uniform Tilings
There are many ways of generating new k-dual-uniform tilings from other k-uniform tilings. Three ways is to scale by as seen below:
Large Fractalization
To enlarge the planigons V32.4.12 and V3.4.3.12 using the truncated trihexagonal method, a scale factor of must be applied:
Big Fractalization
By two 9-uniform tilings in a big fractalization is achieved by a scale factor of 3 in all planigons. In the case of s,C,B,H its own planigon is in the exact center:
The two 9-uniform tilings are shown below, fractalizations of the demiregulars DC and DB, and a general example on S2TC:
Miscellaneous
Centroid-Centroid Construction
Dual co-uniform tilings (red) along with the originals (blue) of selected tilings. Generated by centroid-edge midpoint construction by polygon-centroid-vertex detection, rounding the angle of each co-edge to the nearest 15 degrees. Since the unit size of tilings varies from 15 to 18 pixels and every regular polygon slightly differs, there is some overlap or breaks of dual edges (an 18-pixel size generator incorrectly generates co-edges from five 15-pixel size tilings, classifying some squares as triangles).
Other Edge-Edge Construction Comparisons
Other edge-edge construction comparisons. Rotates every 3 seconds.
Affine Linear Expansions
Below are affine linear expansions of other uniform tilings, from the original to the dual and back:
The first 12-uniform tiling contains all planigons with three types of vertices, and the second 12-uniform tiling contains all types of edges.
Optimized Tilings
If - tiling means dual uniform, Catalaves tiling, then there exists a 11-9 tiling, a 13-10 tiling, 15-11 tiling, a 19-12 tiling, two 22-13 tilings, and a 24-14 tiling. Also exists a 13-8 slab tiling and a 14-10 non-clock tiling. Finally, there are 7-5 tilings using all clock planigons:
Circle Packing
Each uniform tiling corresponds to a circle packing, in which circles of diameter 1 are placed at all vertex points, corresponding to the planigons. Below are the circle packings of the Optimized Tilings and all-edge tiling:
5-dual-uniform 4-Catalaves tilings
A slideshow of all 94 5-dual-uniform tilings with 4 distinct planigons. Changes every 6 seconds, cycles every 60 seconds.
Clock Tilings
All tilings with regular dodecagons in are shown below, alternating between uniform and dual co-uniform every 5 seconds:
65 k-Uniform Tilings
A comparison of 65 k uniform tilings in uniform planar tilings and their dual uniform tilings. The two lower rows coincide and are to scale:
References
Planigon tessellation cellular automata Alexander Korobov, 30 September 1999
B. N. Delone, “Theory of planigons”, Izv. Akad. Nauk SSSR Ser. Mat., 23:3 (1959), 365–386
Types of polygons
Euclidean tilings | Planigon | [
"Physics",
"Mathematics"
] | 3,001 | [
"Tessellation",
"Euclidean plane geometry",
"Euclidean tilings",
"Planes (geometry)",
"Symmetry"
] |
53,413,142 | https://en.wikipedia.org/wiki/Jos%C3%A9%20Luis%20S%C3%A9rsic | José Luis Sérsic (6 May 1933 – 19 July 1993) was an Argentine astronomer who studied the morphology of galaxies. He is most widely known for the mathematical model of galaxy brightness, the Sersic profile, which bears his name. José Luis Sérsic first published his law in 1963.
The asteroid 2691 Sersic is named in his honour.
References
20th-century Argentine astronomers
Argentine people of Croatian descent
1933 births
1993 deaths | José Luis Sérsic | [
"Astronomy"
] | 87 | [
"Astronomers",
"Astronomer stubs",
"Astronomy stubs"
] |
53,413,559 | https://en.wikipedia.org/wiki/Bosanquet%20equation | In the theory of capillarity, Bosanquet equation is an improved modification of the simpler Lucas–Washburn theory for the motion of a liquid in a thin capillary tube or a porous material that can be approximated as a large collection of capillaries. In the Lucas–Washburn model, the inertia of the fluid is ignored, leading to the assumption that flow is continuous under constant viscous laminar Poiseuille flow conditions without considering the effects of mass transport undergoing acceleration occurring at the start of flow and at points of changing internal capillary geometry. The Bosanquet equation is a differential equation that is second-order in the time derivative, similar to Newton's Second Law, and therefore takes into account the fluid inertia. Equations of motion, like the Washburn's equation, that attempt to explain a velocity (instead of acceleration) as proportional to a driving force are often described with the term Aristotelian mechanics.
Definition
When using the notation for dynamic viscosity, for the liquid-solid contact angle, for surface tension, for the fluid density, t for time, and r for the cross-sectional radius of the capillary and x for the distance the fluid has advanced, the Bosanquet equation of motion is
assuming that the motion is completely driven by surface tension, with no applied pressure at either end of the capillary tube.
Solution
The solution of the Bosanquet equation can be split into two timescales, firstly to account for the initial motion of the fluid by considering a solution in the limit of time approaching 0 giving the form
where
and
For the condition of short time this shows a meniscus front position proportional to time rather than the Lucas-Washburn square root of time, and the independence of viscosity demonstrates plug flow.
As time increases after the initial time of acceleration, the equation decays to the familiar Lucas-Washburn form dependent on viscosity and the square root of time.
See also
Hagen–Poiseuille equation
Washburn's equation
References
Equations of fluid dynamics
Porous media | Bosanquet equation | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 430 | [
"Equations of fluid dynamics",
"Equations of physics",
"Porous media",
"Materials science",
"Fluid dynamics"
] |
53,413,868 | https://en.wikipedia.org/wiki/Diplochory | Diplochory, also known as “secondary dispersal”, “indirect dispersal” or "two-phase dispersal", is a seed dispersal mechanism in which a plant's seed is moved sequentially by more than one dispersal mechanism or vector.
The significance of the multiple dispersal steps on the plant fitness and population dynamics depends on the type of dispersers involved. In many cases, secondary seed dispersal by (typically granivorous) invertebrates or rodents moves seeds over a relatively short distance and a large proportion of the seeds may be lost to seed predation within this step. Longer dispersal distances and potentially larger ecological consequences follow from sequential endochory by two different animals, i.e. diploendozoochory: a primary disperser that initially consumes the seed, and a secondary, carnivorous animal that kills and eats the primary consumer along with the seeds in the prey's digestive tract, and then transports the seed further in its own digestive tract.
More than one dispersal vector (abiotic or biotic) is thought to be involved in the majority of seed dispersal events (on average 2.15 dispersal vectors in Dutch ecosystems).
Seeds may be transported in turn by various animal or abiotic mechanisms such as wind or water.
Types of diplochory
Six main types of diplochory have been identified based on the dispersal mechanisms involved:
Wind dispersal (anemochory) & scatter-hoarding (caching) by animals
Ballistic dispersal and myrmechory (dispersal by ants)
Endozoochory and dung beetles
Endozoochory and synzoochory
Endozoochory and myrmechory
Endozoochory and endozoochory
Synzoochory and synzoochory
Diplochory can be beneficial to plants in several ways. When the final phase involves a scatter-hoarder, plant seeds may experience lower predation risk. The caching of seeds by animals such as rodents or birds protects those seeds from being eaten by other seed predators, and because seed hoarders do not recover all the seeds they cached, it may prevent those seeds from being eaten altogether. Ants and dung beetles may also deposit seeds in highly nutritious and fertile habitats that are very favorable for plant growth.
Diploendozoochory
Diploendozoochory is a special form of diplochory in which all stages of the seed dispersal process involve endozoochory by animals. For example, many animals that feed on fruits or seeds are important prey species for a multitude of predators. Where they fall prey while carrying seeds in their digestive system, predators may act as secondary seed dispersers. This kind of predator-assisted seed dispersal was first described by Charles Darwin in 1859, and sporadic observations have since been recorded.
The phenomenon has been studied in most detail in an island system with lizards and raptors that prey on them. In the Canary Islands, frugivorous Atlantic lizards (Gallotia atlantica) consume Lycium intricatum fruit, and thus seeds from the fruit are found in their feces. The lizards are eaten by southern grey shrikes (Lanius meridionalis), and the shrike feces contained seeds from the fruit consumed by the lizards along with lizard remains. On these same islands, common kestrels (Falco tinnunculus) and invasive domestic cats (Felis catus) may also consume these lizards and dispersing the seeds from the lizards’ guts. These lizards also consume other plant species whose seeds may be dispersed by the lizards’ predators, such as Rubia fruticosa, Plocama pendula, and Asparagus nesiotes. Another example of diploendozoochory is that cougars (Puma concolor) eat eared doves (Zenaida auriculata), and as a result disperse seeds from lamb's-quarters (Chenopodium album), panic grass (Panicum bergii), and sorghum (Sorghum bicolor).
Secondary seed dispersal by predators can influence the dispersal distance, habitat in which the seed is deposited, or seed germination potential, that cause seed dispersal outcomes that differ from those of the plant's primary dispersers. While the second phase of diplochory often involves very small-scale movement of the seeds, diploendozoochory can lead to much increased dispersal distance. This is the case especially when the secondary disperser has a larger home range size, is more mobile, or more generalistic in its habitat use than the primary disperser. Because carnivores tend to range over large areas, they can thus help plants colonize new suitable habitats where the possible range changes due to climate change, or reach remote areas such as islands.
Alternative means of dispersal may affect ecological processes such as colonization of disturbed habitats, maintaining gene flow between sites in fragmented habitats, or facilitating long-distance dispersal. Carnivore involvement may also change the predicted patterns of the spread of invasive species, shifting ranges of plant species along climatic gradients, or the recovery of disturbed habitats. In habitats increasingly changed by humans, the presence and actions of carnivores may become increasingly important.
It has also been suggested that plants may have evolved adaptations to benefit from such multi-phase dispersal, making this a mutualistic process. For example, some evidence suggests that island populations have more thick-coated seeds relative to mainland, which may be an adaptation by the plants to tolerate a longer (or multi-phase) digestion as the seeds are transported long distances. However, as the phenomenon has rarely been studied systematically, the prevalence of this seed dispersal mechanism and its importance for plant dispersal is not well understood.
References
Seeds
Plant ecology | Diplochory | [
"Biology"
] | 1,181 | [
"Plant ecology",
"Plants"
] |
53,416,251 | https://en.wikipedia.org/wiki/Moenomycin%20family%20antibiotics | First described in 1965, the moenomycins are a family of phosphoglycolipid antibiotics, metabolites of the bacterial genus Streptomyces. Moenomycin A is the founding member of the antibiotic family with the majority discovered by the end of the late 1970s.
Structure
The moenomycins can be reduced to three key structural features
A central 3-phosphoglyceric acid backbone.
A 25-carbon isoprenoid chain connected by an ether linkage to the C2-position of 3-phosphoglyceric acid.
A substituted tetrasaccharide tethered via a phosphodiester linkage to 3-phosphoglyceric acid.
It is the combination of different isoprenoid chains and variously substituted tetrasaccharides that give rise to the diversity of the moenomycin family.
Based on degradation experiments, the defining mark of a moenomycin is the presence of the 25-carbon alcohol moenocinol or diumycinol upon hydrolysis of the lipid tail; these alcohols originate from the L1 or L2 lipid respectively in the figure. These two structures are the only observed lipid tails within the moenomycin family, with AC326-α being the only known for producing diumycinol.
With regards to the tetrasaccharide portion, stereochemistry and functionality can differ at R1 and R2 depending on if this saccharide unit is D-gluco versus D-galacto; there is an axial methyl group in the former case with the exception of moenomycin A12 and C1 where there is instead an axial hydroxyl. The oligosaccharide motif can be deoxygenated, hydroxylated, or glycosylated at the R3 position – notable examples of the pentasaccharide motif include moenomycin A and AC326-α. It is believed the additional glycan can enhance specificity and binding to the target protein, affording increased activity. With the exception of pholipomycin and AC326-α, the R4 saccharide unit is usually the deoxysaccharide. Lastly, in the majority of moenomycins the R5 position is linked to a 2-aminocyclopentane-1,3-dione – a convenient chromophore utilized for structural analysis. For the nosokomycin subfamily, this position forms a carboxamide or carboxylic acid.
Chemical synthesis
Due to the structural complexity of the moenomycins, total synthesis has proved difficult, with only one total synthesis reported so far. Some of the largest challenges include fashioning the glycosidic linkages with stereochemical control and site-specifically decorating the oligosaccharide with pendant functionality. Understanding that the majority of variation within the moenomycin family derives from differences within the oligosaccharide unit, Kahne and lab has designed an efficient and flexible total synthesis of moenomycin A that gives access to analogues as well as other members of the moenomycin family.
Biosynthesis
Extensive exploration into the biosynthesis of the moenomycin family has been conducted to better inform the genetic engineering and biosynthesis of novel moenomycin analogues. Early work on the biosynthesis of the moenomycins focused on the 25-carbon lipid tail derived from moenocinol; the tail was of particular interest given that it appears to break the isoprene rule at C8, containing a quaternary carbon. Feeding studies revealed the moenocinol lipid tail originates from a 15-carbon farnesyl precursor and a 10-carbon geranyl pyrophosphate.
More recently, the biosynthetic gene cluster for moenomycin A was first described in 2007 in Streptomyces ghanaensis. In 2009, the seventeen step biosynthetic pathway was completely characterized, revealing the order of assembly for the molecular scaffold.
Medicinal use
The moenomycins target bacterial peptidoglycan glycosyltransferases, inhibiting cell wall formation, leading to cell death. In general, the antibiotics are particularly potent against gram-positive bacteria with a minimum inhibitory concentration (MIC) between 1–100 (ng/ml). At higher concentrations the moenomycins are also effective against gram-negative bacteria with an MIC between 0.3–150 (μg/ml). In vivo studies using mice models suggest the antibiotics are powerful prophylactic and therapeutic agents, with subcutaneous injection being the most effective mode of delivery.
Moenomycins A and C are commercially used in the formulation of Bambermycins (Flavomycin), a veterinary antibiotic used solely in poultry, swine, and cattle feed.
Due to poor pharmacokinetic properties from the 25-carbon lipid chain, the moenomycins are not used in humans. The pharmacophore is well understood however, allowing the moenomycins to serve as the blueprint for future antibacterials.
Mode of action
General
The moenomycin family functions as an antibiotic by reversibly binding bacterial transglycosylases, essential enzymes that catalyze the extension of the glycan chain of the cell wall to form a stable peptidoglycan layer. The moenomycins mimic and thus compete with the natural substrate of the enzyme, inhibiting growth of the cell wall. Compromise of the wall results in leakage of cell contents, and ultimately cell death. The moenomycins are the only known active site inhibitors of these enzymes, which in lies their promise as human antibiotics given pathogenic bacteria have not yet widely evolved resistance.
Structure-activity relationships
The 25-carbon lipid tail confers to the moenomycins a detergent-like property that allows them to become incorporated into the cytoplasmic membrane of the target bacterial cell. This anchoring presents the oligosaccharide portion of the molecule to the transglycosylase where it can tightly and selectively bind the enzyme, inhibiting cell wall growth. This property however undermines their use in clinical settings. The amphiphilic nature of the moenomycins induce hemolytic activity, provide a long half-life in the blood stream, and creates a tendency to aggregate in aqueous solution. Comparison of moenomycins with an abridged isoprene chain of 10-carbons, show that the oligosaccharide can still tightly bind the enzyme active site, but in vivo the MIC significantly increases since the drug is unable to anchor itself to the cytoplasmic membrane and present its sugar moiety. Further studies are needed to determine the optimal length for favorable pharmacokinetic properties.
In contrast to the lipid portion, the oligosaccharide portion of the moenomycins is relatively well understood. When absent, the chromophore portion can decrease activity by 10-fold, suggesting it is not necessary for recognition but provides additional contacts with the target enzyme.
References
Antibiotics | Moenomycin family antibiotics | [
"Biology"
] | 1,528 | [
"Antibiotics",
"Biocides",
"Biotechnology products"
] |
53,416,632 | https://en.wikipedia.org/wiki/Cold%20metal%20transfer | Cold metal transfer (CMT) is a welding method that is usually performed by a welding robot. The CMT machine detects a short circuit which sends a signal that retracts the welding filler material, giving the weld time to cool before each drop is placed. This leaves a smooth weld that is stronger than that of a hotter weld. This works well on thin metal that is prone to warping and the weld burning through the material. This type of welding is more efficient than other GMAW methods when the metal is thinner than 10mm, anything thicker and the expense begins to overcome traditional welding. Welding wire is fed through the system that is controlled by a computer, the computer adjusts things such as wire feed, welding speed, and amps going through the wire. This allows precise welding of materials like steel and aluminum, with very little slag and spatter, resulting in a cleaner finish weld.
Definition
CMT is a subset of gas metal arc welding. It works by reducing the weld current and retracting the weld wire when detecting a short circuit, resulting in a drop-by-drop deposit of weld material. Developed for thin materials, CMT requires strict control of weld parameters.
History
CMT was originally intended for joining sheet metal in the automotive industry, but has expanded to thicker materials.
Application
Cold metal transfer is used to weld different types of metal with various thicknesses. This low voltage, low heat welding works well on thin sheet metal. It is also being used for thicker material where the integrity of the weld is important. When metal is overheated it affects its structural properties; CMT welding keeps the heat to a minimum, resulting in little change to the structure of the metal, and a stronger weld. Thin metal has a greater possibility of distorting when heated. During traditional GMAW welding, heat sinks or other heat protection had to be used to prevent the warping of the metal. Heat protection is not needed during the CMT process. CMT has a wide variety of applications in various industries such as small engine, automotive, and marine.
Specifications
References
External links
Cold metal transfer , Fronius welding processes
Welding
Austrian brands | Cold metal transfer | [
"Engineering"
] | 451 | [
"Welding",
"Mechanical engineering"
] |
53,416,784 | https://en.wikipedia.org/wiki/OpenXR | OpenXR is an open-source, royalty-free standard for access to virtual reality and augmented reality platforms and devices. It is developed by a working group managed by the Khronos Group consortium. OpenXR was announced by the Khronos Group on February 27, 2017, during GDC 2017. A provisional version of the standard was released on March 18, 2019, to enable developers and implementers to provide feedback on it. On July 29, 2019, OpenXR 1.0 was released to the public by Khronos Group at SIGGRAPH 2019 and on April 15, 2024, OpenXR 1.1 was released by Khronos.
Reviewers of the 0.90 provisional release considered that the aim of OpenXR was to "Solve AR/VR Fragmentation".
Architecture
The standard provides an API aimed for application developers targeting virtual reality or augmented reality hardware. This enables developers to build applications that will work across a wide variety of devices.
The fundamental elements of this API are:
XrSpace: a representation of the 3D space
XrInstance: a representation of the OpenXR runtime
System and XrSystemId: a representation of the devices, including the Virtual reality or Augmented reality devices and controllers
XrActions: used to handle user inputs
XrSession: represents the interaction session between the application and the user
The full specification can be found via the OpenXR Registry on GitHub.
Implementations
The Khronos Group maintains the list of OpenXR-conformant platforms and products.
Currently conformant OpenXR platforms are:
Acer's Spatial Display Series
Bytedance's Neo3 and PICO4
Canon's MREAL platform display and headsets
Collabora Monado Runtime for GNU/Linux, with the release of version 21.0.0 in February 2021
HTC VIVE Cosmos and VIVE Focus 3, part of HTC's VIVERSE ecosystem
Magic Leap 2
Meta's PC platform and its Quest line of devices, with full support OpenXR 1.0 added in July 2021
Microsoft HoloLens 2 and the Windows Mixed Reality headsets
Qualcomm Snapdragon Spaces XR Developer Platform
Sony's Spatial Reality Displays (ELF-SR1 & ELF-SR2)
Valve SteamVR, since version 1.16 in February 2021
Varjo headsets
Game and rendering engine support
Support for OpenXR application development can be found in the following engines:
Unreal Engine, with initial support in the 4.24
Blender, with initial support in the 2.83 LTS release from June 2020
Unity, with initial support in the 2020.2 release from December 2020
Godot, with initial support in the 4.0
Autodesk VRED
StereoKit, developed around OpenXR
Nvidia Omniverse
Unigine since version 2.19 from August 2024.
Browser support
Google Chrome and Microsoft Edge web browsers both enable WebXR support using OpenXR by default using the Chromium code base
Roadmap
After the release of OpenXR 1.0, progress will likely be driven through the development of extensions to the core API. This can be seen in the subsequent release of extensions for support of hand tracking and eye gaze tracking.
As implementers and developers get more experience with the extensions, they could get integrated into the core OpenXR API in future releases.
Contributors
The following companies are listed by Khronos as public supporters of OpenXR:
See also
Proprietary counterparts
References
External links
OpenXR 1.0 specification
3D graphics APIs
Application programming interfaces
Graphics standards
Video game development
Video game engines
Virtual reality
Augmented reality
Mixed reality
Metaverse
Spatial computing | OpenXR | [
"Technology"
] | 756 | [
"Computer standards",
"Graphics standards"
] |
54,680,276 | https://en.wikipedia.org/wiki/NGC%207083 | NGC 7083 is an unbarred spiral galaxy located about 134 million light-years away in the constellation of Indus. It is also classified as a flocculent spiral galaxy. NGC 7083 was discovered by astronomer James Dunlop on August 28, 1826.
Supernovae
Three supernovae have been observed in NGC 7083:
SN 1983Y (type unknown, mag. 18) was discovered by Marina Wischnjewsky on 14 April 1983.
SN 2009hm (type Ib, mag. 14.7) was codiscovered by Stuart Parker and Berto Monard on 17 July 2009.
SN 2019qar (type Ib-pec, mag. 17.5) was discovered by the Distance Less Than 40 Mpc Survey (DLT40) on 12 September 2019.
See also
List of NGC objects (7001–7840)
NGC 4414
References
External links
Unbarred spiral galaxies
Flocculent spiral galaxies
Indus (constellation)
7083
67023
Astronomical objects discovered in 1826 | NGC 7083 | [
"Astronomy"
] | 214 | [
"Indus (constellation)",
"Constellations"
] |
54,681,026 | https://en.wikipedia.org/wiki/Kepler-1625b | Kepler-1625b is a super-Jupiter exoplanet orbiting the Sun-like star Kepler-1625 about away in the constellation of Cygnus. The large gas giant is approximately the same radius as Jupiter, and orbits its star every 287.4 days. In 2017, hints of a Neptune-sized exomoon in orbit of the planet was found using photometric observations collected by the Kepler Mission. Further evidence for a Neptunian moon was found the following year using the Hubble Space Telescope, where two independent lines of evidence constrained the mass and radius to be Neptune-like. The mass-signature has been independently recovered by two other teams. However, the radius-signature was independently recovered by one of the teams but not the other. The original discovery team later showed that this latter study appears affected by systematic error sources that may influence their findings.
Characteristics
Mass and radius
Kepler-1625b is a Jovian-sized gas giant, a type of planet several times greater in radius than Earth and mostly composed of hydrogen and helium. It is 11.4 times Earth's radius, approximately equal to that of the planet Jupiter. However, it is up to 11.6 times more massive (about 3,700 Earth masses), based on radial velocity observations. This puts it just below the deuterium-fusing limit, which is around 13 Jupiter masses. Any more massive and Kepler-1625b would be a brown dwarf. However, this mass value only corresponds to an 3-sigma upper limit and the mass of the planet remains undetected at this time.
Orbit and temperature
Unlike the gas giants in our Solar System, Kepler-1625b orbits much closer, slightly closer than the orbital radius as the Earth around the Sun. The planet takes to orbit Kepler-1625, as a result of the star's slightly greater mass than the Sun. Kepler-1625b receives 2.6 times more insolation than the Earth, meaning it lies at the inner edge of the habitable zone. However, as the planet has likely no solid surface, bodies of liquid water are impossible.
Candidate exomoon
In July 2017, researchers found signs of a Neptune-sized exomoon (a moon in another solar system) orbiting Kepler-1625b using archival Kepler Mission data.
In October 2018, researchers using the Hubble Space Telescope published new observations of the star Kepler-1625 which revealed two independent lines of evidence indicative of a large exomoon Kepler-1625b I. These were a 20-minute Transit Timing Variation signature that indicated an approximately Neptune-mass moon, and an additional photometric dip that indicated a Neptune-radius moon. The relative phasing of the two signatures was also consistent with that which a real moon would cause, with the effects in anti-phase. The study concluded that the exomoon hypothesis is the simplest and best explanation for the available observations, though warned that it is difficult to assign a precise probability to its reality and urged follow-up analyses.
In February 2019, a reanalysis of the combined Kepler and Hubble observations recovered both a moon-like dip and similar transit timing variation signal. However, the authors suggested that the data could also be explained by an inclined hot-Jupiter in the same system that has gone previously undetected, which could be tested using future Doppler spectroscopy radial velocity measurements. A second independent reanalysis was published in April 2019, which recovered one of the two lines of evidence, the transit timing variation, but the not the second, the moon-like dip. The original discovery team responded to this soon after, finding that this re-analysis exhibits stronger systematics in their reduction which may be responsible for their differing conclusion.
References
Giant planets in the habitable zone
Exoplanets discovered by the Kepler space telescope
Exoplanets discovered in 2016
Cygnus (constellation) | Kepler-1625b | [
"Astronomy"
] | 783 | [
"Cygnus (constellation)",
"Constellations"
] |
54,681,275 | https://en.wikipedia.org/wiki/Geography%20of%20media%20and%20communication | Geography of media and communication (also known as communication geography, media geography and geographies of media) is an interdisciplinary research area bringing together human geography with media studies and communication theory. Research addressing the geography of media and communication seeks to understand how acts of communication and the systems they depend on both shape and are shaped by geographical patterns and processes. This topic addresses the prominence of certain types of communication in differing geographical areas, including how new technology allows for new types of communication for a multitude of global locations.
Overview
Geography of media and communication is an area of research, which considers various facets of communication. One interest is the layout and organization of communication systems at scales from cities to the planet. Closely related to this are the varying levels of access to communication systems from place to place. Attention to how places differ in regard to communication access leads to an interest in the changes that occur in places when new media diffuse into those places. A complementary interest is in how places are represented in various media—for example pictures of idyllic beaches in tourism advertisements or written descriptions of war zones in newspaper stories. Communications also allow people to interact with distant places, so a final area of investigation is how, by interacting with others through various kinds of communication systems, people inhabit various kinds of "virtual" spaces.
Of particular interest to media/communication theorists are questions regarding the social and cultural formations associated with media, which in turn point to how media are involved in the transformation of belonging and citizenship, which relate to geographical territories. Social and cultural formations also depend on distinctions between public and private life, which have traditionally depended on spatial boundaries between public and private places. Topics of particular interest to geographers are place representations in visual media including photography, film and graffiti, in auditory media including radio and music recordings, and even in embodied communications such as dance and video games.
History
Geographical interest in the systematic study of communication can be traced to the writings of Richard Hartshorne in the 1930s. Hartshorne considered language to be a key element forming culture regions, meaning that the dominant language is similar within a particular culture region and it changes when one leaves a culture region. A very different aspect of communication became the focus during the 1950s and 1960s as geographers began to measure and model the interactions between locations. In this case, geographers involved in the quantitative revolution explained the accelerating flow of information between locations in terms of "time-space convergence" and "human extensibility." It was not until the 1970s that geographers began to focus on communications in terms of content, considering questions of symbolism, representation, metaphor, iconography and discourse. This interest first took form in geographical research that drew on humanism, phenomenology and hermeneutics. By the 1990s, this approach shifted towards a more critical sensibility unpacking the various meanings of landscape. Geographers researching communication over the past two decades have extended these research areas while carrying forward early insights regarding the importance of communication to the formation of regions, the rate of information flow as a measure of spatial interaction, and the association between landscape and representation. New approaches to communication have been advanced under the frameworks of non-representational theory, actor-network theory, and assemblage theory. Equally important is the effort to think through digital code and its relationship with space.
Evolution of Geographic Communication
Throughout different areas of the world, certain types of communication are used more in certain places, and have evolved over time. America and other developed countries have gotten information and communicated within their local communities through newspapers and other forms of written communication in the past and present, but in the cases of certain types of communication such as environmental and risk communication, there has been a shift as newspapers are no longer the most effective form of communication. Part of the shift in communication over time comes from an increased presence of social media.
Social Media Evolution
Social media caused a new experience in geographical communication as it allowed instant contact with various people around the globe. Social media communication has been tracked through the United States, and on certain social media platforms there is the ability to track and log communication to and from all areas of the world. For example, the Twitter accounts of various geography departments have been used to show how interaction is divided within local, national, and global lines of communication, while also being able to analyze other aspects of the communication data. This is seen as when viewing common days of the week which are active or which months show heavy interaction between accounts. Analysis of larger cities throughout the world shows that social media has become a predominant force in communication for many communities. While there may be similar exposure to social media in wildly different areas across the world, evidence shows that the same type of social media communication is not equally effective in differing areas. Geographical locations with larger populations of higher education levels will interact and understand communication through social media more effectively than areas with lower education levels. While social media can be used to communicate information within and between communities throughout the world, it can also be an influence in public perception of rumors and risks. This study was conducted in 2015 when South Korea became panicked over a disease because of the rumors circling through social media about the disease and how it was negatively affecting people of the country. Based on the findings from this research, social media has a large influence on public perception throughout communities.
Areas of study
According to one taxonomy, the geography of media and communication involves four complementary aspects: places-in-media, media-in-places, media-in-spaces and spaces-in-media. Places-in-media are representations of place circulating in all sorts of media for all sorts of reasons, for example landscape paintings signifying the owner's status, and news images of urban spaces linking crime and chaos to minority populations and the poor. Media-in-places are ways in which particular places such as the home, classroom, workplace, or city street are altered functionally and experientially by transformations in how people use media in those places. Media-in-spaces are communication infrastructures, whether historical, like telegraph cables, or contemporary like optical fiber cable when mapped and analyzed in terms of their physical layout. Spaces-in-media are the topologies that symbols, images, information and ideas move through as they spread or diffuse from person to person and from group to group.
Notable scholars
Geographers interested in media and communication
Ronald F. Abler
John A. Agnew
Paul C. Adams
Henry Bakis
Trevor J. Barnes
Jacquelin Burgess
Denis Cosgrove
Tim Cresswell
Julie Cupples
Simon Dalby
Jason Dittmer
Klaus Dodds
Peter Gould
Mark Graham
Derek Gregory
Eric Laurier
Chris Lukinbeal
Doreen Massey
John Pickles
Gillian Rose (Geographer)
Nigel Thrift
Yi-Fu Tuan
Gearóid Ó Tuathail / Gerard Toal
Gill Valentine
Philippe Vidal
Torsten Wissmann
Stefan Zimmermann
Media/communication scholars interested in geography
Manuel Castells
Elizabeth Eisenstein
Kevin Glynn
Harold Innis
Marshall McLuhan
Joshua Meyrowitz
Lewis Mumford
Walter J. Ong
Lisa Parks
Neil Postman
Mary Louise Pratt
Saskia Sassen
Mimi Sheller
See also
Cultural geography
Social geography
Political geography
Geopolitics
Urban geography
Feminist geography
External links
Media Geography at Mainz
Media and Communication Specialty Group of the AAG
Geomedia Strong Research Group, Karlstad University, Sweden
Notes
Human geography
Mass media
Communication | Geography of media and communication | [
"Environmental_science"
] | 1,496 | [
"Environmental social science",
"Human geography"
] |
54,682,827 | https://en.wikipedia.org/wiki/Barricade%20on%20Jerusalem%20Avenue%2C%20Warsaw | The barricade on Jerusalem Avenue was a defense structure built and manned by soldiers of the Bełt and Kilinski Battalions of the Home Army to protect a narrow passage between North Downtown to South Downtown during the Warsaw Uprising in 1944. It was located between 23 (then 17) and 27 Jerusalem Avenue in Warsaw.
Origin
After the Tehran Conference, where it was decided that German-occupied territories of Poland would be liberated by the Soviet Army, command of the Polish Armed Forces in the West formed a strategy to defend its borders based on the largest insurgent army in Europe – the Home Army. The strategy made its mark in history as Operation Tempest. Home Army soldiers were to attack German forces in large cities and welcome Soviet soldiers as guests on their soil. The Operation was successful in a number of cities, however, the Soviets immediately began to neutralize any sort of Polish resistance. The greatest challenge of the entire operation was an uprising in the Polish capital– Warsaw. In late July 1944, an operational plan of liberating the capital was created. The key elements consisted of capturing and defending main transport routes connecting western districts of Warsaw with the Praga district such as Wolska street, Leszno street, and Jerusalem Avenue. The Germans priority was to maintain a steady connection with the eastern bank of Vistula river, where Soviet troops were advancing. The Home Army, however, had to hold a connection between Srodmiescie Polnocne (Northern Downtown) and Srodmiescie Poludniowe (Southern Downtown). The “Bolt” Battalion led by Lieutenant Erwin Brenneisen was tasked with operating in that area.
Order de Bataille
The battalion's area of operation covered the odd side of Jerozolimskie Avenue, Marszalkowska Street, Three Crosses Square, Bracka Street and Nowy Swiat Street. The most important task of the battalion was to enable the Germans from marching through Jerusalem Avenue. Additionally, the battalion was ordered to build and protect a communication ditch which was to connect southern and northern parts of Srodmiescie. This ditch-barricade was intended to be built under heavy enemy fire from both sides of the avenue. The insurgents expected tanks, assault cannons, “Goliaths”, mortars and machine guns to be used by the Germans. The construction itself was conducted by “Bylinski Stanislaw” and “Andrzej” – Andrzej Lebdowicz. Their task was difficult – tramway tracks and an underground railroad stood in their way.
The beginning of the uprising
At the “W” Hour, the “Bolt” Battalion of 180 men was stationed on Sniadeckich Street in Southern Downtown (Srodmiescie Poludniowe). In the late evening Brenneisen received an order to move to the south of Jerusalem Avenue to the area of Marszalkowska and Bracka Street. They were tasked with closing German west-east communications. The battalion was aided by the “Wik” Company commanded by Lieutenant Zenon Wiktorczyk and now had a manpower of around 350 people with little gain in firepower. The defense of the communication ditch was based on the barricade built between Krucza St. and Marszalkowska St. Civilians from nearby townhouses actively helped in the barricades construction. The task of breaking ground with pickaxes between houses No. 17 and 22 turned out to be extremely difficult. The tramway tracks had to be blown up using dynamite, which was in little supply already. The underground railroad posed even a bigger problem – its concrete ceiling was impossible to breach with simple pickaxes, that's why sandbags and flagstone were used to fortify most of the barricade. Those fortifications were systematically destroyed by German mortar fire, “Goliaths” and air support. The “Kilinski” Battalion worked on the southern part of the ditch.
The barricade was constructed in early August and it served an important role as the only connection between southern and northern parts of the city.
The invincible barricade
The biggest threat to the barricade was the close proximity of the enemy forces. The Germans were stationed in building No. 25 (just five buildings from the barricade), on the corner of Bracka St. in a small garden next the Bank Gospodarstwa Krajowego (BGK) building, and on the opposite side in the “Cristal” restaurant. The Germans managed to reach Krucza St. at night and create fortified positions. Battalions commander gave an order to neutralize these positions. An attack on building No. 25 was led by lt. “Zych” and lt. “Miś” on August 10, 1944 in the afternoon. In this successful attempt the insurgents managed to push back the Germans, take a few prisoners, capture a large amount of ammunition and weapons and free the tenants, who were crammed in the basement. An attack on the eastern side was led by lt. “Skiba”. Conducted during the night, it was successful in pushing back the Germans away from Bracka St. and out of the small garden next to the BGK building. This resulted in a new stronghold held by the insurgents on the corner of Jerusalem Avenue and Bracka St. In late September, after the Old Town and Powisle (riverside) have fallen, the enemy intensified his attacks from the Central Railway Station along Nowogrodzka St. and Jerusalem Avenue. The Germans tried to destroy the barricade in order to split the downtown area in two separate caldrons using the most gruesome methods such as “live shields” – forcing civilians to walk in front of advancing tanks. Commander of this area major “Sarna”, expected it and gave an order to fortify his positions. “Skiba” to take command over the entire crew that operated on the western section. The Germans had an enormous advantage over the insurgents in this area, especially in guns and firepower. “Skiba” said not to fallback even by a single step. The exhausting fighting continued during the night. In the most critical moment, when ammunition was in short supply – bottles filled with petrol were thrown into the action. Flames and fierce resistance of the insurgents managed to stop the Germans. 3 enemy “Goliaths” and 4 tanks were destroyed. The Germans did not regain control over the barricade and Jerusalem Avenue until the end of the uprising
References
Warsaw Uprising
Śródmieście Południowe
Śródmieście Północne
1944 establishments in Poland
1944 disestablishments in Poland
Military installations established in 1944
Military installations closed in 1944
Buildings and structures in Poland destroyed during World War II
World War II defensive lines
Former buildings and structures in Warsaw
World War II sites in Warsaw | Barricade on Jerusalem Avenue, Warsaw | [
"Engineering"
] | 1,395 | [
"World War II defensive lines",
"Fortification lines"
] |
54,682,902 | https://en.wikipedia.org/wiki/Rana%20Dajani | Rana Dajani () is a Jordanian molecular biologist and tenured professor of biology and biotechnology at Hashemite University. She earned her Ph.D. in molecular biology from the University of Iowa. Dajani is an expert on genetics of Circassian and Chechen populations in Jordan, also on conducting genome-wide association studies on diabetes and cancer on stem cells. Her work in stem cell research initiated the development of the Stem Cell Research Ethics Law and all regulations in Jordan. She is an advocate for the biological evolution theory in relation to the religion of Islam, and believes strongly in the education and empowerment of women, being a member of the United Nations Women Jordan Advisory Council. She is the recipient of the Jordan's Order of Al Hussein for Distinguished Contributions of the Second Class.
Dajani is the president of the Society for Advancement of Science and Technology in the Arab World [5](SASTA). Dr. Dajani is a Fulbright scholar alumna, having received two awards. She was a fellow at the Radcliffe Institute for Advanced Study at Harvard University, and possessed an Eisenhower Fellowship as well. She is also a former Yale University visiting professor at the Yale Stem Cell Center and a visiting scholar at both the University of Cambridge and the Stem Cell Therapy Center in Jordan. She was the 2019-21 Zuzana Simoniova Cmelikova Visiting Scholar at the Jepson School of Leadership Studies at the University of Richmond
Dr. Dajani is the founder and director of the non-governmental organization, "We Love Reading," a program which strives to foster a love of reading in young children beyond academics in the Arab world. Through We Love Reading, she has trained over 7000 women to read aloud in Jordan, Lebanon and Syria and established multiple libraries across Jordan.
The UK-based Muslim Science Magazine[10] praised her as one of the most influential women scientists in the Islamic World; and Arabian Business lists Dajani as one of “The World’s 100 Most Powerful Arab Women," in which she ranked number thirteen.
Personal life
Dajani is born to a Palestinian father and a Syrian mother, however, she holds the Jordanian passport. When asked about her nationality, she describes herself as "half Palestinian and half Syrian with a Jordanian passport."
Dajani is the mother of four children.
Education
Dr. Dajani first gained a General Certificate of Education from the University of London in 1985, before studying for her bachelor's degree in biology at the University of Jordan. She then pursued her master's degree, also in Biology, at the same university in 1992. She won the First Honors Award for both. She attended the University of Iowa in 2005, earning a Ph.D. in molecular biology.
Career
Dajani's career life is extensive, having been described as “not a straight line, but a zigzag of priorities and opportunities.” Starting out as a lecturer at the Philadelphia University immediately after graduating from her Master's program, she then taught for five years at the Amman Academy. Around 2005, she was an assistant professor at the Hashemite University, moving on to become a tenured professor. In September 2012, she visited the Genetics Department at Yale University as an assistant professor. She has also been a mentor at Stanford University's AMENDS program since 2012, and an advisor on the Fetzer Advisory Council on the Natural Sciences at the Fetzer Institute. In addition, since March 2019, she has been a member at the advisory board for Mustafa Prize Foundation. At the moment, she is a visiting scholar at the University of Richmond and a consultant for the company Alpha Sights,. [12] She is also the co-founder of the Islamic World Academy for Young Scientists (ISESCO). Other than a substantial list of faculty academic appointments, she has appeared as a judge on several prize-winning initiations such as the Nature Inspiring Award, the Hult Prize at the Hashemite University, and Innovation lab IRC.
Extending out of her own field, she also founded an NGO called, We Love Reading, “Taghyeer” (the Arabic word meaning change), training women to read aloud, and establishing libraries in different areas in Jordan, inciting a love of reading in young children in 2009. She was the director for the Center for Service Learning at the Hashemite University from 2009 to the year 2010, then became the director of the Center for Studies at the same university, from 2011 to 2012. She has been appointed a Higher Education Reform Expert by TEMPUS Jordan.
Dr. Dajani's work branches out, seeing as she is a freelance journalist from the year 2011 to the present. She has been an editor at Frontiers in Immunology and Muslim-Science.com. She has also consulted for many companies, including DQS UL Jordan, Triangle Research Group and Epic Education.
Dajani is a strong advocate for the empowering of women, being a member of many organizations such as ASRF Women Innovators in Charge Jury in July 2016 and has been on the UN Women Jordan Advisory Council since 2013 to the present. Mentoring many, she also created a toolkit needed in order for the women she trained to “pay it forward” and train others as well.
We Love Reading
After graduating and returning to Jordan, Dajani realized that Jordan has no public libraries, unlike the 9,000 present in the States, in almost every neighborhood. After research, she realized that children who read for pleasure grow up to exhibit stronger language skills, better academic performance, and a greater emotional intelligence. Due to that, she set out to start a program that would initiate a love of reading in young children. She began her first read-aloud session in a mosque, which can be found in almost every neighborhood in Jordan and allows for all to enter. As the read-alouds garnered more popularity, she began training other women in the techniques of storytelling as well.
Since its founding in 2010, We Love Reading has trained over 7000 women to read aloud and established about 1500 libraries across different areas in Jordan. By 2024, the programme has established over 4,000 libraries in 60 countries, going so far as to be present in many refugee camps.
Through We Love Reading, Dajani has won multiple awards including the Library of Congress Literacy Award Best Practices, a Stars Impact Award, the Synergos Arab World Social Innovator award, a WISE Award, and recognition from IDEO.org. She has also won the UNESCO International Literacy Prize.
Honors and awards
The U.S. Embassy in Jordan in concert with the U.S. Embassy Amman's Environment, Science, Technology and Health Office for the Middle East and North Africa inducted Dajani into the Women in Science Hall of Fame in 2015. This honor recognized her work and theories on biological evolution and Islam, focusing on genome-wide research on diabetes, cancer and stem cells. She was instrumental in establishing the terms of law for the use of stem cell therapy in Jordan, which opened the door for regulation in the Arab and Islamic world.
Her work in We Love Reading won the UNESCO's King Sejong Literacy Prize. The outcome of this led to the establishment of 330 libraries throughout Jordan, enriching the literacy of over 10,000 children, 60% of whom were female. For this work she received the following honors: the 2015 Star Award for education impact; a 2015 honor for the 50 Most Talented Social Innovators at the World CSR Congress; the 2015 OpenIDEO "Top Idea" for child refugees; she received the Library of Congress Literary Award for Best Practices in 2013; and in 2009 she received the Synergos award for Arab world social innovators.
In 2009 Dajani received the King Hussein Cancer Center & Biotechnology Institute award. In 2010, she was inducted into the membership of the Clinton Global Initiative of the Clinton Foundation. In 2014 Dajani won the WISE Qatar Award, and the King Hussein Medal of Honor. In October 2017 she was selected by Radcliffe Institute for Advanced Study as a fellow of the Radcliffe Institute Fellowship Program at Harvard University.
List of received awards
Below is a list of the awards she has received;
UNHCR MENA Nansen Award 2020 for ‘We Love Reading’
Arab Science and Technology Foundation 2019 Award in service of the advancement of science and technology
Jacob Klaus Social Entrepreneurship Award 2018
World Literacy Summit award 2018
UI Carver College of Medicine's Distinguished Alumni Awards 2018
UNHCR's Protecting Urban Refugee Children Innovation Challenge Winner 2017
Jordan Star of Science, Category Biology, His Majesty King Abdullah II of Jordan, World Science Forum 2017
UNESCO King Sejong International Literacy Prize 2017
We Love Reading: Refugee-led Reading Circle, Promising Practices in Refugee Education initiative 2017 Pearson, UNHCR and Save the children 2017
Runner up for the Core77 design awards for social impact 2017
Aspen Ideas Festival 1 scholar 2017
Harvard Radcliffe Fellowship award 2017
World HRD Congress Women Super Achiever Award 2017
On the list of 500 most influential Muslims 2015, 2016, 2017 and 2021
PEER Award 2014 for the project “The Three Circles of Alemat,” PI, NSF/USAID, 2014-2017
The inaugural IIE Global Change-maker Award in celebration of the 70th Anniversary of Fulbright 2016
The Arab Women Association Golden Award 2015
Top idea in the IDEO challenge 2015
Honored by his Majesty King Abdullah II of Jordan as a woman leader 2015
Ranked #12 in CEO Middle East magazine's list of 100 Most Powerful Arab Women 2015
Women in Science hall of fame, US Embassy Amman's Environment, Science, Technology, and Health Office for the Middle East, 2015
The Stars Award for Impact 2014
Ranked 13 in CEO Middle East magazine's list of 100 Most Powerful Arab Women 2014
50 Most Talented Social Innovators 2015 at the World CSR Congress
Order of Al Hussein for Distinguished Contributions of the Second Class. Granted to "those who have made distinguished contributions to society" 2014
Winner for the WISE Award 2014
Eisenhower Fellowship innovative program 2014
"We Love Reading” recognized by Center for Education Innovation, 2014
Selected as one of the 100 most powerful Arabs in the World 2014 in the category “geniuses” by Arabian Business magazine
Named one of the list of GOOD 2014
"We Love Reading” recognized by UNESCO, 2014
Named one of the most influential women scientist of the Islamic world 2014 by UK based Muslim Science magazine
Named Citizen of the Next Century List for 2013
Library of congress Literacy Award for best practices for “We Love Reading,” 2013
Fulbright Occasional Lecture Award Spring 2013
Fulbright Research Scholarship first place, 2012-2013 Research at Yale University Stem cells and micro RNA
Featured in the Innovation for education book by Charles Leadbeater, WISE Qatar Foundation, 2012 book
Finalist for the “women in academia network” for the Alumni Engagement innovation fund by the State alumni, 2011
Nominated by the Hashemite University for the “Women in Science” award offered by the Islamic Development Bank (2011)
Complimentary membership to the Clinton Global Initiative 2010
"Ahel el Himmeh” initiative, nominated for the award and got voted in the final 30 runner-ups for “We Love Reading”
Awarded the 2009 Arab world social innovator award by Synergos for the project "we love reading"
Nominated as one of Ahel Al-Himmeh. An initiative by Queen Rania of Jordan to recognize individuals from the Jordan community who do volunteer work for the community and have made a difference
The King Hussein Cancer Institute for cancer and biotechnology award 2009
Fulbright Alumni Development Awards (ADA) 2008
Fulbright Scholar 2000-2002
Howard Hughes Medical Institute predoctoral award - honorary mention in 2001
Publications and speaking engagements
Dajani is a member of the United Nations' Jordanian Women's Advisory Council. She has published in several peer-reviewed and in Science and Nature journals. Among her speaking engagements is the Templeton-Cambridge Journalism Fellowship symposium at the University of Cambridge; Massachusetts Institute of Technology, McGill University, and at the British Council Belief in Dialogue conference.
In 2018 she published Five Scarves: Doing the Impossible - If We Can Reverse Cell Fate, Why Can’t We Redefine Success? on the subject of inequities in education and employment.
In 2019 she published We Love Reading - An Introduction.
References
Year of birth missing (living people)
Living people
University of Iowa alumni
Academic staff of Hashemite University
Academic staff of Philadelphia University (Jordan)
Radcliffe fellows
Eisenhower Fellows
Yale University people
Women molecular biologists
Jordanian biologists
Jordanian women scientists
Theistic evolutionists
Muslim women
Writers about religion and science
Science activists
Muslim evolutionists
Recipients of Al-Hussein Order for Distinguished Contributions | Rana Dajani | [
"Biology"
] | 2,556 | [
"Non-Darwinian evolution",
"Theistic evolutionists",
"Biology theories"
] |
54,683,524 | https://en.wikipedia.org/wiki/Federal%20Ministry%20of%20Petroleum%20Resources | The Federal Ministry of Petroleum Resources is a part of the Federal Ministries of Nigeria that directs petroleum resources and its activities in Nigeria.
History
In the beginning, Petroleum matters were handled by the Hydrocarbon Section of the Ministry of Lagos Affairs, which reported directly to the Governor-general.
The Unit delivered responsibilities such as: keeping records on exploration matters, and importation of petroleum products; enforcing safety and other regulations on matters which were then mostly products importation and distribution, etc.
The Unit was upgraded to a Petroleum Division within the Ministry of Mines and Power, with the expansion of the petroleum industry activities. In 1971, the Nigerian National Oil Corporation (NNOC) was created to handle direct commercial operational activities in the oil industry on behalf of the Federal Government. However, the Department of Petroleum Resources in the Federal Ministry of Mines and Power continued to exercise statutory supervision and control of the industry. In 1975, the department was upgraded to a ministry named, the Ministry of Petroleum and Energy which was later renamed the Ministry of Petroleum Resources. Then in 1985, the Ministry of Petroleum Resources was re-established.
Organizational structure
The ministry has one permanent secretary, nine directors, two deputy directors and an assistant director heading their various departments. The Minister is a political appointee, while the Permanent Secretary who is a veteran civil servant and the Chief Accounting Officer of the Ministry. The Permanent Secretary reports all the affairs of the Ministry to the Minister, while the Directors in the Ministry report to the Permanent Secretary. The Ministry has twelve Directorates, each headed by a Director, namely:
Department of Human Resources Management
Department of Planning
Department of Research and Statistics
Department of Press and public relations
Department of Finance and Accounts
Legal Department
Department of Procurement
Department of Gas
Department of Oil Services
Department of reforms Co-ord
Department of General Services
Department of Internal Audit
Department of Special Duties
Each Department has various divisions and sections. Deputy Directors head divisions, and Assistant Directors head sub-sections/units. Directors report directly to the Permanent Secretary, Deputy Directors report to the Directors, and Assistant Directors report to the Deputy Directors.
Each of the Departments has various divisions and sections in a hierarchical/pyramid setting headed by deputy directors, and the assistant directors heading sub-sections/units. The Directors report directly to the Permanent Secretary, while the deputy directors report to the Directors and the assistant directors report to the deputy directors respectively. The Ministry of Petroleum Resources operational frame work operates in a hierarchical level from the top management cadre down to the middle/junior executive cadre.
Leadership
President Bola Tinubu is not the Minister of Petroleum Resources appointed Heineken Lokpobiri as the Minister of State for Petroleum Resources (Oil) and Ekperikpe Ekpo as Minister of State for Petroleum Resources (Gas) in August 2023. They replaced Timipre Sylva who took over the Ministerial portfolio in August 2019.
Amb. Nicholas Agbo Ella, Esq, is the current Permanent Secretary, Ministry of Petroleum Resources.
Mission
Ensure an enabling environment to improve the Oil and Gas value chain, driven by modern technology, industry, best practices, stakeholders' engagement and innovations in alternative energy.
Functions
Initiation and formulation of the board policies and programmes on the development of the Petroleum sector (Oil and Gas) in general;
All policies matters on the marketing of crude oil, natural gas, Petroleum products and their derivatives;
All concession policies in the oil and gas sub-sectors of the energy sector of the economy;
Formulation of policies to stimulate private industry investment and participation in the oil and gas sectors;
Administration of government joint venture interests in the Petroleum sector in order to maximize fully economic benefits derivable from Nigeria's oil and gas resources and ensuring optimization of government interest in all oil and gas arrangements;
Licensing of all Petroleum and gas operations and activities;
Policy matters relating to research and development in Petroleum and Gas sectors of the Petroleum industry;
Development of hydro-carbon industries including natural gas, processing, refineries and Petrochemical industries through public private partnership;
Formulation of policies to ensure increase of natural oil and gas reserve base and Nigeria's increased technical productivity in accordance with appropriate planning and allocation of production quotas to producing companies in line with OPEC quota and maximization of revenue from oil and gas to the Nation;
Coordination and supervision of all bilateral and multilateral relations affecting the energy (Oil and Gas) Sector; Overall supervision and coordination of the activities of the following parastatals and its subsidiaries.
Parastatals
Nigerian Upstream Petroleum Regulatory Commission (NUPRC)
Nigerian Mid- and Downstream Petroleum Regulatory Authority (NMDPRA)
Petroleum Training Institute (PTI)
Nigeria Nuclear Regulatory Authority (NNRA)
Nigerian Content Development Monitoring Board (NCDMB)
Petroleum Technology Development Fund (PTDF)
References
External links
Nigerian Upstream Petroleum Regulatory Commission (NUPRC) website
Nigerian Mid- and Downstream Petroleum Regulatory Authority (NMDPRA) website
Petroleum Training Institute (PTI) website
Nigeria Nuclear Regulatory Authority (NNRA) website
Nigerian Content Development Monitoring Board (NCDMB) website
Petroleum Technology Development Fund (PTDF) website
PTDF Scholarship Application
Petroleum in Nigeria
Federal Ministries of Nigeria
Ministries established in 1970
Energy ministries | Federal Ministry of Petroleum Resources | [
"Engineering"
] | 1,037 | [
"Energy organizations",
"Energy ministries"
] |
54,685,170 | https://en.wikipedia.org/wiki/Life%20That%20Glows | Life That Glows (also known as David Attenborough's Light on Earth) is a 2016 British nature documentary programme made for BBC Television, first shown in the UK on BBC Two on 9 May 2016. The programme is presented and narrated by Sir David Attenborough.
Life That Glows depicts the biology and ecology of bioluminescent organisms, that is, organisms capable of creating light. The programme features fireflies, who use light as a means of sexual attraction, luminous fungi, luminous marine bacteria responsible for the Milky seas effect, the flashlight fish, the aposematism of the Sierra luminous millipede, earthworms, and the bioluminescent tides created by blooms of dinoflagellates in Tasmania, as well as dolphins swimming in the bloom in the Sea of Cortez, the defensive flashes of brittle stars and ostracods, sexual attraction in ostracods, prey attraction by luminous click beetles in Cerrado, Brazil and Arachnocampa gnats in New Zealand.
The programme then introduces many luminous deep sea animals, including the vampire squid, the polychaete worm Tomopteris that generates yellow light, the jellyfish Atolla, the comb jelly Beroe, the viper fish, pyrosomes, a dragonfish, and the polychaete worm Flota. Next, the programme discusses specialised adaptations in the eyes of particular animals to see bioluminescence, such as the barreleye fish and the cock-eyed squid. Lastly, the programme features the mass spawning event of the firefly squid in Japan.
External links
2010s British documentary television series
2016 British television series debuts
2016 British television series endings
David Attenborough
BBC television documentaries
Documentary films about nature
Bioluminescence | Life That Glows | [
"Chemistry",
"Biology"
] | 358 | [
"Biochemistry",
"Luminescence",
"Bioluminescence"
] |
54,686,113 | https://en.wikipedia.org/wiki/Downcast%20%28app%29 | Downcast is a podcast client application for iOS, macOS, and watchOS. It was originally developed by Seth McFarland of Jamawkinaw Enterprises LLC and is currently being developed and maintained by George Cox of Tundaware LLC.
References
External links
Mobile applications
IOS software
Podcasting software | Downcast (app) | [
"Technology"
] | 61 | [
"Mobile software stubs",
"Mobile technology stubs"
] |
54,686,533 | https://en.wikipedia.org/wiki/Cross%20slip | In materials science, cross slip is the process by which a screw dislocation moves from one slip plane to another due to local stresses. It allows non-planar movement of screw dislocations. Non-planar movement of edge dislocations is achieved through climb.
Since the Burgers vector of a perfect screw dislocation is parallel to the dislocation line, it has an infinite number of possible slip planes (planes containing the dislocation line and the Burgers vector), unlike an edge or mixed dislocation, which has a unique slip plane. Therefore, a screw dislocation can glide or slip along any plane that contains its Burgers vector. During cross slip, the screw dislocation switches from gliding along one slip plane to gliding along a different slip plane, called the cross-slip plane. The cross slip of moving dislocations can be seen by transmission electron microscopy.
Mechanisms
The possible cross-slip planes are determined by the crystal system. In body centered cubic (BCC) metals, a screw dislocation with b=0.5<11> can glide on {110} planes or {211} planes. In face centered cubic (FCC) metals, screw dislocations can cross-slip from one {111} type plane to another. However, in FCC metals, pure screw dislocations dissociate into two mixed partial dislocations on a {111} plane, and the extended screw dislocation can only glide on the plane containing the two partial dislocations. The Friedel-Escaig mechanism and the Fleischer mechanism have been proposed to explain the cross-slip of partial dislocations in FCC metals.
In the Friedel-Escaig mechanism, the two partial dislocations constrict to a point, forming a perfect screw dislocation on their original glide plane, and then re-dissociate on the cross-slip plane creating two different partial dislocations. Shear stresses then may drive the dislocation to extend and move onto the cross-slip plane. Atomic simulations have confirmed the Friedel-Escaig mechanism.
Alternatively, in the Fleischer mechanism, one partial dislocation is emitted onto the cross-slip plane, and then the two partial dislocations constrict on the cross-slip plane, creating a stair-rod dislocation. Then the other partial dislocation combines with the stair-rod dislocation so that both partial dislocations are on the cross-slip plane. Since the stair rod and the new partial dislocations are high energy, this mechanism would require very high stresses.
Role in plasticity
Cross-slip is important to plasticity, since it allows additional slip planes to become active and allows screw dislocations to bypass obstacles. Screw dislocations can move around obstacles in their primary slip plane (the plane with the highest resolved shear stress). A screw dislocation may glide onto a different slip plane until it has passed the obstacle, and then can return to the primary slip plane. Screw dislocations can then avoid obstacles through conservative motion (without requiring atomic diffusion), unlike edge dislocations which must climb to move around obstacles. Therefore, some methods of increasing the yield stress of a material such as solid solution strengthening are less effective because due to cross slip they do not block the motion of screw dislocations.
At high strain rates (during stage II work hardening), discrete dislocation dynamics (DD) simulations have suggested that cross-slip promotes the generation of dislocations and increase dislocation velocity in a way that is dependent on strain rate, which has the effect of decreasing flow stress and work hardening.
Cross slip also plays an important role in dynamic recovery (stage III work hardening) by promoting annihilation of screw dislocations and then movement of screw dislocations into a lower energy arrangement.
See also
Slip
Plastic deformation
Miller indices
References
Materials science
Crystallographic defects | Cross slip | [
"Physics",
"Chemistry",
"Materials_science",
"Engineering"
] | 837 | [
"Applied and interdisciplinary physics",
"Crystallographic defects",
"Materials science",
"Crystallography",
"nan",
"Materials degradation"
] |
54,687,306 | https://en.wikipedia.org/wiki/Structural%20rejuvenation | Structural rejuvenation is a change in bulk metallic glasses which, among other consequences, improves their plasticity.
There are two kinds of structural rejuvenation: homogeneous and inhomogeneous.
References
Amorphous metals | Structural rejuvenation | [
"Physics"
] | 48 | [
"Materials stubs",
"Unsolved problems in physics",
"Amorphous metals",
"Materials",
"Amorphous solids",
"Matter"
] |
54,690,624 | https://en.wikipedia.org/wiki/PA-99-N2 | PA-99-N2 is a microlensing event detected in the direction of the Andromeda Galaxy in 1999.
Explanations
One possibility for the event is that a star in the disk of M31 gravitationally lensed a red giant also in the disk. The lensing star would have a mass between and with the most likely value near . In this case the lens profile makes it likely that the star has a planet.
Possible exoplanet
The possible exoplanet would have a mass of 6.34 Jupiter mass. If confirmed, it would be the first exoplanet found in another galaxy. A similar event was seen in 1996 when a team of astronomers discovered an anomalous fluctuation in the Twin Quasar's lightcurve that seemed to be caused by a planet approximately three Earth masses in size in the quasar's lensing galaxy YGKOW G1. (However, the results remain speculative because the chance alignment that led to its discovery will never happen again; if that exoplanet could be confirmed, it would be the most distant known planet, 4 billion ly away.)
References
Andromeda (constellation)
Gravitational lensing
Extragalactic stars
Andromeda Galaxy | PA-99-N2 | [
"Astronomy"
] | 254 | [
"Andromeda (constellation)",
"Constellations"
] |
54,692,968 | https://en.wikipedia.org/wiki/Network%20eavesdropping | Network eavesdropping, also known as eavesdropping attack, sniffing attack, or snooping attack, is a method that retrieves user information through the internet. This attack happens on electronic devices like computers and smartphones. This network attack typically happens under the usage of unsecured networks, such as public wifi connections or shared electronic devices. Eavesdropping attacks through the network is considered one of the most urgent threats in industries that rely on collecting and storing data. Internet users use eavesdropping via the Internet to improve information security.
A typical network eavesdropper may be called a Black-hat hacker and is considered a low-level hacker as it is simple to network eavesdrop successfully. The threat of network eavesdroppers is a growing concern. Research and discussions are brought up in the public's eye, for instance, types of eavesdropping, open-source tools, and commercial tools to prevent eavesdropping. Models against network eavesdropping attempts are built and developed as privacy is increasingly valued. Sections on cases of successful network eavesdropping attempts and its laws and policies in the National Security Agency are mentioned. Some laws include the Electronic Communications Privacy Act and the Foreign Intelligence Surveillance Act.
Types of attacks
Types of network eavesdropping include intervening in the process of decryption of messages on communication systems, attempting to access documents stored in a network system, and listening on electronic devices. Types include electronic performance monitoring and control systems, keystroke logging, man-in-the-middle attacks, observing exit nodes on a network, and Skype & Type.
Electronic performance monitoring and control systems (EPMCSs)
Electronic performance monitoring and control systems are used by employees or companies and organizations to collect, store, analyze, and report actions or performances of employers when they are working. The beginning of this system is used to increase the efficiency of workers, but instances of unintentional eavesdropping can occur, for example, when employees' casual phone calls or conversations would be recorded.
Keystroke logging
Keystroke logging is a program that can oversee the writing process of the user. It can be used to analyze the user's typing activities, as keystroke logging provides detailed information on activities like typing speed, pausing, deletion of texts, and more behaviors. By monitoring the activities and sounds of the keyboard strikes, the message typed by the user can be translated. Although keystroke logging systems do not explain reasons for pauses or deletion of texts, it allows attackers to analyze text information. Keystroke logging can also be used with eye-tracking devices which monitor the movements of the user's eyes to determine patterns of the user's typing actions which can be used to explain the reasons for pauses or deletion of texts.
Man-in-the-middle attack (MitM)
A Man-in-the-middle attack is an active eavesdropping method that intrudes on the network system. It can retrieve and alter the information sent between two parties without anyone noticing. The attacker hijacks the communication systems and gains control over the transport of data, but cannot insert voice messages that sound or act like the actual users. Attackers also create independent communications through the system with the users acting as if the conversation between users is private.
The “man-in-the-middle” can also be referred to as lurkers in a social context. A lurker is a person who rarely or never posts anything online, but the person stays online and observes other users' actions. Lurking can be valuable as it lets people gain knowledge from other users. However, like eavesdropping, lurking into other users' private information violates privacy and social norms.
Observing exit nodes
Distributed networks including communication networks are usually designed so that nodes can enter and exit the network freely. However, this poses a danger in which attacks can easily access the system and may cause serious consequences, for example, leakage of the user’s phone number or credit card number. In many anonymous network pathways, the last node before exiting the network may contain actual information sent by users. Tor exit nodes are an example. Tor is an anonymous communication system that allows users to hide their IP addresses. It also has layers of encryption that protect information sent between users from eavesdropping attempts trying to observe the network traffic. However, Tor exit nodes are used to eavesdrop at the end of the network traffic. The last node in the network path flowing through the traffic, for instance, Tor exit nodes, can acquire original information or messages that were transmitted between different users.
Skype & Type (S&T)
Skype & Type (S&T) is a new keyboard acoustic eavesdropping attack that takes advantage of Voice-over IP (VoIP). S&T is practical and can be used in many applications in the real world, as it does not require attackers to be close to the victim and it can work with only some leaked keystrokes instead of every keystroke. With some knowledge of the victim’s typing patterns, attackers can gain a 91.7% accuracy typed by the victim. Different recording devices including laptop microphones, smartphones, and headset microphones can be used for attackers to eavesdrop on the victim's style and speed of typing. It is especially dangerous when attackers know what language the victim is typing in.
Tools to prevent eavesdropping attacks
Computer programs where the source code of the system is shared with the public for free or for commercial use can be used to prevent network eavesdropping. They are often modified to cater to different network systems, and the tools are specific in what task it performs. In this case, Advanced Encryption Standard-256, Bro, Chaosreader, CommView, Firewalls, Security Agencies, Snort, Tcptrace, and Wireshark are tools that address network security and network eavesdropping.
Advanced encryption standard-256 (AES-256)
It is a cipher block chaining (CBC) mode for ciphered messages and hash-based message codes. The AES-256 contains 256 keys for identifying the actual user, and it represents the standard used for securing many layers on the internet. AES-256 is used by Zoom Phone apps that help encrypt chat messages sent by Zoom users. If this feature is used in the app, users will only see encrypted chats when they use the app, and notifications of an encrypted chat will be sent with no content involved.
Bro
Bro is a system that detects network attackers and abnormal traffic on the internet. It emerged at the University of California, Berkeley that detects invading network systems. The system does not apply to the detection of eavesdropping by default, but can be modified to an offline analyzing tool for eavesdropping attacks. Bro runs under Digital Unix, FreeBSD, IRIX, SunOS, and Solaris operating systems, with the implementation of approximately 22,000 lines of C++ and 1,900 lines of Bro. It is still in the process of development for real-world applications.
Chaosreader
Chaosreader is a simplified version of many open-source eavesdropping tools. It creates HTML pages on the content of when a network intrusion is detected. No actions are taken when an attack occurs and only information such as time, network location on which system or wall the user is trying to attack will be recorded.
CommView
CommView is specific to Windows systems which limits real-world applications because of its specific system usage. It captures network traffic and eavesdropping attempts by using packet analyzing and decoding.
Firewalls
Firewall technology filters network traffic and blocks malicious users from attacking the network system. It prevents users from intruding into private networks. Having a firewall in the entrance to a network system requires user authentications before allowing actions performed by users. There are different types of firewall technologies that can be applied to different types of networks.
Security agencies
A Secure Node Identification Agent is a mobile agent used to distinguish secure neighbor nodes and informs the Node Monitoring System (NMOA). The NMOA stays within nodes and monitors the energy exerted, and receives information about nodes including node ID, location, signal strength, hop counts, and more. It detects nodes nearby that are moving out of range by comparing signal strengths. The NMOA signals the Secure Node Identification Agent (SNIA) and updates each other on neighboring node information. The Node BlackBoard is a knowledge base that reads and updates the agents, acting as the brain of the security system. The Node Key Management agent is created when an encryption key is inserted to the system. It is used to protect the key and is often used between Autonomous Underwater Vehicles (AUVs), which are underwater robots that transmit data and nodes.
Snort
Snort is used in many systems, and it can be run in an offline mode using stream4. Stream4 reassembles preprocessors with another stream option. The snort-reply patch feature is often used to reconstruct executions. It is currently developed by Cisco and acts as a free network intrusion detection system.
Tcptrace
Tcptrace is used to analyze pcap-based network intercepts, which is a packeting capture network application that detects network traffic. It has an important feature that monitors eavesdropping attacks and can reconstruct captured TCP streams.
Wireshark
Wireshark, or also named Ethereal, is a widely used open-source eavesdropping tool in the real world. Most of the features in Ethereal are packet-oriented and contain a TCP reassembly option for experiments on tracking intrusion attempts.
Models against the attacks
Models are built to secure system information stored online and can be specific towards certain systems, for example, protecting existing documents, preventing attacks on the processing of instant messages on the network, and creating fake documents to trace malicious users.
Beacon-bearing decoy documents
Documents containing fake but private information such as made-up social security numbers, bank account numbers, and passport information will be purposely posted on a web server. These documents have beacons that will be triggered when a user attempts to open them, which then alarms another site that records the time accessed of the documents and IP address of the user. The information collected from the beacons is then regularly sent to Tor exit nodes which then the user will be caught in the malicious act.
Butterfly encryption scheme
The Butterfly encryption scheme uses timestamps and updates pseudorandom number generators (PRNG) seeds in a network system to generate authentication keys and parameters for encrypted messages to be sent out. This scheme can perform in entities that are searching for a relatively low cost but efficient security scheme, and can work in different systems as it has a simple design that is easy to modify for specific purposes. The Butterfly encryption scheme is effective because it uses a changing parameter and has an unpredictable timestamp that creates a high-level security system.
Crypto phones (Cfones)
Cfones is a model built to protect VoIP communications. It uses Short Authenticated Strings (SAS) protocol that requires users to exchange keys to ensure no network intruders are in the system. This is specific to communication systems that involve both voice messages and text messages. In this model, a string is given to actual users, and to connect with another user, strings have to be exchanged and have to match. If another user tries to invade the system, the string will not match, and Cfones blocks attackers from entering the network. This model is specific to preventing man-in-the-middle attacks.
Friendly-jamming schemes (DFJ and OFJ)
Friendly-jamming schemes (DFJ and OFJ) are models that can decrease the eavesdropping risk by purposely interfering the network when an unknown user is near the area of the protected area. The models are tested by the probability of eavesdrop attacks in a testing environment, and are found that there is a lower probability of attacks compared to a system with no friendly-jamming schemes installed. A feature of the DFJ and OFJ schemes is that the models offer a large coverage secure area that is protected from eavesdroppers effectively.
Honey encryption scheme (HE)
A honey encryption scheme is used to strengthen the protection of private information of instant messaging systems, including WhatsApp and Snapchat, as well as tracking down the eavesdropper’s information. HE contains fake but similar plaintext during the decryption phase of the process of instant messaging with an incorrect key. This makes messages that the eavesdropper is trying to decrypt to be gibberish messages. HE schemes are used in specific systems not limited to instant messaging systems, passwords, and credit cards. However, applying it to other systems is still a difficult task as changes inside the scheme have to be made to fit the system.
Internet of Things framework (IoT)
The Internet of Things framework involved four layers of security measures that are management layer, cloud layer, gateway layer, and IoT device layer. The management layer handles web and mobile applications. The cloud layer looks over the service and resource management. It acts as an access point for users to connect to other internet services. The gateway layer manages the packet filtering module. It links the endpoint network of the services, processes the documents or information, and contains security tasks including authentication, authorization, and encryption. The two main tasks of the gateway layer are to detect users and perform filtering of the actual user and malicious users. The IoT device layer looks over the gateway layer’s performance and double-checks whether all malicious users are removed from the network, specifically, attestation is a mechanism to measure the end-point integrity and removes nodes from the network if necessary.
Cases of network eavesdropping
Completely trusting network devices or network companies can be risky. Users of devices are oftentimes unaware of the threats on the internet and choose to ignore the importance of protecting their personal information. This paves the way for malicious hackers to gain access to private data that users may not be aware of. A few cases of network eavesdropping discussed include Alipay and Cloud computing.
Alipay
Private information from a user of mobile payment apps, in this case, Alipay, is retrieved using a hierarchical identification specific to mobile payment apps. The system first recognizes the app used from traffic data, then categorizes the user’s distinct actions on the app, and lastly distinguishes comprehensive steps within each action. Distinct actions on mobile payment apps are generalized in a few groups including making a payment, transfer money between banks, scanning checks, and looking at previous records. By classifying and observing the user’s specific steps within each group of actions, the attacker intercepts the network traffic using and obtains private information of app users. Strategies to prevent incidents are made such as fingerprint or facial identification, and email or text confirmation of actions performed on the app.
Cloud computing
Cloud computing is a computing model that provides access to many different configurable resources, including servers, storage, applications, and services. The nature of the Cloud makes it vulnerable to security threats, and attackers can easily eavesdrop on the Cloud. Particularly, an attacker can simply identify the data center of the Virtual Machine used by cloud computing, and retrieve information on the IP address and domain names of the data center. It becomes dangerous when the attacker gains access to private cryptographic keys for specific servers which they may get data stored in the cloud. For example, the Amazon EC2 platform based in Seattle, Washington, WA, USA, was once at risk of such issues but has now used Amazon Web Service (AWS) to manage their encryption keys.
Medical records
Sometimes users can choose what they put online and should be responsible for their actions, including whether or not a user should take a photo of their social security number and send it through a messaging app. However, data like medical records or bank accounts are stored in a network system in which companies are also responsible for securing user’s data. Medical records of patients can be stolen by insurance companies, medical laboratories, or advertising companies for their interests. Information such as name, social security number, home address, email address, and diagnosis history can be used to track down a person. Eavesdropping reports of a patient’s medical history is illegal and is dangerous. To deal with network threats, many medical institutes have been using endpoint authentication, cryptographic protocols and data encryption.
Related laws and policies
Electronic Communications Privacy Act (ECPA)
In Title III of the Electronic Communications Privacy Act (ECPA), it states that it is a “federal crime to engage in wiretapping or electronic eavesdropping; to possess wiretapping or electronic eavesdropping equipment; to use to disclose information obtained through illegal wiretapping or electronic eavesdropping, or to disclose information secured through court-ordered wiretapping or electronic eavesdropping, to obstruct justice.” Federal and state law enforcement officials may be allowed to intercept with the wire, oral, and electronic communications if and only if a court order is issued, consent of the parties, or when a malicious user is trying to access the system. If the law is violated, there may be a criminal penalty, civil liability, administrative and professional disciplinary action, and or exclusion of evidence. A general penalty is not more than five years of imprisonment and no more than $250,000 for individuals and not more than $500,000 for organizations. If damages are created, there may be a $100 fine per day of violation or $10,000 in total.
Foreign Intelligence Surveillance Act (FISA)
The Foreign Intelligence Surveillance Act gives out court orders for “electronic surveillance, physical searches, installation, and use of pen registers and traps and trace devices, and orders to disclose tangible items.” Court orders issued on electronic surveillance allow the federal officials to use electronic surveillance which includes eavesdropping without violating the Electronic Communications Privacy Act or Title III specifically.
Organization of Economic Cooperation and Development (OECD)
A guideline to protecting the privacy of data of health patients is issued by the Organization of Economic Cooperation and Development (OECD). The policy states that individual patient data or personal data should be secure, and patients will not face any arbitrary losses related to invading their personal information or health conditions. The policy acts as a minimum standard for eHealth usages and it should be followed by all medical institutes for protecting the privacy of patient’s data.
See also
Black hat (computer security)
Crowdsensing
Eavesdropping
Endpoint detection and response
Endpoint security
Intrusion detection system
Packet analyzer
Security hacker
Van Eck phreaking
References
Computer networking
Computer security | Network eavesdropping | [
"Technology",
"Engineering"
] | 3,863 | [
"Computer networking",
"Computer science",
"Computer engineering"
] |
76,204,084 | https://en.wikipedia.org/wiki/Californium%28III%29%20nitrate | Californium(III) nitrate is an inorganic compound of californium and iodine with the formula . It can be used as a precursor to other californium compounds.
References
Californium compounds
Nitrates | Californium(III) nitrate | [
"Chemistry"
] | 49 | [
"Inorganic compounds",
"Nitrates",
"Salts",
"Oxidizing agents",
"Inorganic compound stubs"
] |
76,204,175 | https://en.wikipedia.org/wiki/Goldbeck%20Solar | Goldbeck Solar GmbH is a solar energy company headquartered in Hirschberg an der Bergstraße in Baden-Württemberg. The company offers utility-scale photovoltaic systems for open spaces or industrial and commercial roofs, as well as their commissioning and maintenance in Europe, South and North America and Central Asia.
History
In 2001, entrepreneur Joachim Goldbeck founded Goldbeck Solar GmbH as a subsidiary of the Bielefeld-based Goldbeck Group in Ichtershausen near Erfurt. Initially, Goldbeck Solar focused on the installation of photovoltaic systems on industrial buildings and commercial roofs and developed the "Sunovation" substructure system.
In 2004, the company headquarters were relocated to Hirschberg an der Bergstraße in Baden-Württemberg. In 2007, the company began its international expansion and increasingly built ground-mounted solar power plants in Germany and abroad. The first large ground-mounted projects were completed in Spain in 2008. The following year, the company expanded to the Czech Republic and Slovakia, and in 2011 to the United Kingdom.
In 2010, Goldbeck Solar developed a mounting system for flat-roof solar systems in collaboration with German companies Ensinger and BASF. The firm launched the substructure for this system under the "Sunolition" brand. In 2015, Goldbeck Solar took over the operations of Soventix and Gehrlicher Solar.
Solarnet GmbH, also founded by Joachim Goldbeck, oversees Goldbeck Solar's non-European business and made its initial expansion into Latin America and Asia in 2016. In 2017, Goldbeck Solar established a branch in Mexico City and entered the Chilean and Thai markets. During the same year, Chint Solar and Goldbeck Solar completed the "Solar Park Veendam" project in Veendam, the Netherlands.
Amidst a downturn in the European solar market starting in 2015, Joachim Goldbeck, then managing director of construction firm Goldbeck Group, planned a €100 million investment in the Kazakh solar market. This initiative led to disagreements within Goldbeck Group, culminating in the establishment of Goldbeck Solar as an independent entity in 2018. Joachim Goldbeck Holding GmbH has since been operating as the controlling company of Goldbeck Solar. Solarnet and Goldbeck Solar Investment were subsequently established as affiliated companies to manage Goldbeck Solar's photovoltaic projects, including financing and commercial operation.
Goldbeck Solar has also been present in the Kazakh market since 2018, where it built the largest solar power plant in Central Asia in 2018 on an area of 160 hectares in the Karaganda region.
In 2020, the subsidiary Zonnepark Services was founded in the Netherlands together with Chint Solar.
In 2022, Goldbeck Solar took over the North American PV business of GP Joule. This was officially renamed Goldbeck Solar Canada / USA in 2023 (formerly: GP Joule Canada / USA). The completion of the "Youngstown Solar Park" in Alberta, which is expected to generate around 13,000 megawatt hours of electric energy per year, was announced in late 2023. In December 2023, Goldbeck Solar and Suncatcher Gruppe sold a solar power complex in Barlinek, Poland.
In the beginning of 2024, two solar parks in Chile were put into operation.
Corporate structure
Joachim Goldbeck Holding GmbH is the main shareholder of Goldbeck Solar GmbH.
The managing directors of Goldbeck Solar are Joachim Goldbeck, Tobias Roland Schüssler and Michiel Vanhouette. In the 2023 financial year, the company generated sales of €218.8 million and employed 150 people. Joachim Goldbeck Holding GmbH holds 98% of the shares in Goldbeck Solar.
Subsidiaries of Goldbeck Solar GmbH are:
Goldbeck Solar España S.L., Madrid/Spain
Solar Polska Sp z o.o., Komorniki/Poland
Goldbeck Solar Ltd, Birmingham/England
Goldbeck Solar Nederland B.V., Zuidbroek/Netherlands
Too Pv Construction, Saran/Kazakhstan
Goldbeck Italia S.L.R. Bergamo/Italy
Zonnepark Services Nederland B.V., Utrecht/Netherlands
Goldbeck Solar Thailand Co, Ltd, Bangkok/Thailand
Goldbeck Solar Canada Corp., Toronto/Canada
Managing director Joachim Goldbeck has also been the President of the German Solar Industry Association (BSW-Solar) since 2014.
Products and services
Goldbeck Solar offers turnkey installations of commercial photovoltaic systems for open spaces or commercial roofs in Europe, Central Asia and North and South America. The company also provides maintenance services for solar power plants. Goldbeck Solar plans, builds and maintains solar plants and parks, Goldbeck Solar Investment develops, finances and operates solar projects and the third branch of Goldbeck Solar holds a majority stake in PMT, which develops and produces substructures for solar plants.
Together with the Fraunhofer ITWM, Goldbeck Solar also developed the "Solar Planner" software, which calculates system variants and makes them economically comparable.
References
External links
Goldbeck Solar GmbH – Website
Goldbeck Solar North America
Solar energy companies
Photovoltaics manufacturers | Goldbeck Solar | [
"Engineering"
] | 1,039 | [
"Photovoltaics manufacturers",
"Engineering companies"
] |
76,204,736 | https://en.wikipedia.org/wiki/Leibniz%20Institute%20of%20Surface%20Engineering | The Leibniz Institute of Surface Engineering e.V. (abbreviation: IOM) is a publicly funded research organisation based in Leipzig, Germany. It is a member of the Leibniz Association.
The IOM was founded on the 1.1.1992 with the aim of investigating the fundamental physical and chemical processes in the field of non-thermal material transformation that enable important contributions to surface engineering using ions, electrons, plasmas and photons. The goal is to develop new functional and precise surfaces for future-oriented fields of application. The range of tasks includes research of fundamental phenomena and the transfer of scientific results into industrial applications.
Several spin-off companies have been founded from the IOM and numerous patents and utility models have been granted for developments.
Structure & financing
The IOM is a registered association under the name "Leibniz-Institut für Oberflächenmodifizierung e.V." (Leibniz Institute of Surface Engineering) based in Leipzig, which, according to its statutes, pursues exclusively and directly non-profit and peaceful purposes.
The IOM has four bodies: the General Assembly, the Board of Trustees, the Executive Board and the Scientific Advisory Board. The tasks of the Board of Trustees include all fundamental matters and activities of the IOM as well as advising and monitoring the work of the Executive Board. The duties of the Executive Board are primarily to manage the business of the IOM. The Scientific Advisory Board advises the Board of Trustees and the Executive Board on all scientific and structural issues.
The IOM is financed by grants and donations and is also funded by the federal and state governments in accordance with Article 91b of the German Basic Law. In addition, project funds can be acquired from third parties and used for research purposes.
In total, there were 134 employees at the institute in 2022, of which 75 were academic staff, 34 technical staff, 14 administrative staff and 11 others (scholarship holders, trainees, etc.).
History
Predecessor institutes during the GDR period
The Institute of Surface Engineering (IOM) emerged from the "Institute for Physical Separation of Materials" founded in 1957 under the direction of Prof Justus Mühlenpfordt. This was later renamed the "Institute for Stable Isotopes" (ISI).
Following a reform of the academy (1968 - 1972), the ISI was dissolved, but became the "Central Institute for Isotope and Radiation Research" (ZfI) and was headed by Prof Klaus Wetzel until 1989 (formally 1990). Both institutes belonged to the Academy of Sciences of the GDR.
As part of the university reform, it was decided that the academies and universities should focus their "research on solving important problems for the development of socialist society, the national economy, the health system, education and culture in the GDR" (§ 2 of the research ordinance). Accordingly, research at the institute was subject to state influences and wishes. For more information on this, see.
The main topics of work at the ZfI were: Accelerator technology, electron beam hardening of thin films, applied radiation chemistry, applied radiation biology, ion beam technology and pulse radiolysis.
Founding of the IOM
The Institute of Surface Engineering (IOM) was officially founded on 1 January 1992 as a Blue List Institute of the Leibniz Association. The founding director was Prof Frieder Bigl. This was preceded by the dissolution of the ZfI on 31 December 1991 as part of the reorganisation of research institutes following the German reunification.
A founding committee chaired by Prof Klaus Bethge was already planning the new foundation in 1991. In this context, it was also decided that the new institute should be called "Institut für Oberflächenmodifizierung e.V." (Leibniz Institute of Surface Engineering) and be a registered association. The status of the institute as a Blue List institute was also decided.
The IOM was divided into two departments: "Ion Beam Technology" headed by Prof Frieder Bigl and "Electron Beam Technology" headed by Prof Reiner Mehnert. Both departments were also divided into working groups and focussed on device development or application-oriented topics. Interdisciplinary cooperation was a clearly formulated goal of both departments from the start.
Research between 2000 and 2009
In mid-2000, Prof Bernd Rauschenbach took over the management of the Institute from Prof Frieder Bigl.
The "Ion Beam Technology" department was taken over by Prof Rauschenbach. Under his leadership, research was conducted in various working groups on the topics of fundamentals and new applications, surface precision processing, device technology fundamentals and laser structuring and laser ablation.
The "Electron Beam Technology" department was headed by Prof Mehnert until January 2005, after which Prof Michael Buchmeiser took over this role from January 2006. The individual working groups in this department dealt with the following topics: electron beam technology, accelerator technology, (plasma) polymer modification and process engineering.
In autumn 2001, an additional building was constructed, including a technology hall to house pilot plants, a cleanroom, physical and chemical laboratories and numerous offices for employees. In 2003-04, a laboratory and office extension and a new technology transfer building were started and completed.
Research between 2010 and 2021
In 2010, the institute had around 150 employees. The scientists continued to conduct research in the fields of ion, plasma, electron and photon interaction with surfaces and thin films.
The "Ion Beam Technology" department was renamed the "Physics Department" and headed by Prof Rauschenbach, who remained Director of the Institute. In 2010, there were working groups on the following topics:
· Surface precision processing
· Plasmajet process development
· Device technology basics
· Laser structuring and laser ablation
· Layer deposition and structuring
· Inorganic / organic interfaces and coatings
The "Electron Beam Technology" department was renamed the "Chemistry Department", but remained without a head following the departure of Prof Michael Buchmeiser in 2009. Prof Bernd Abel, who also became Deputy Director of the IOM, took over as head of the department in May 2012. In 2010, there were working groups on the following topics:
· Basic research on polymer layers
· Functional layers
· Polymer modification
· Biofunctional polymers
In May 2012, the Leipzig nanoAnalytical Centre (LenA) was opened to mark the 20th anniversary of the institute. The central instrument of the LenA centre is a high-resolution transmission electron microscope (TEM) model "Titan", which enables material science investigations down to the atomic scale.
In 2015, the "Hertz Application Laboratory" (today: Hertz Electron Beam Laboratory) and the installation of a 10 MeV electron accelerator created an infrastructure that is unique in Germany for basic research in the field of materials science and for industry-related projects on material modification using high-energy electrons (up to 10 MeV).The IOM's new application centre (APZ for short) was inaugurated in autumn 2016. The APZ is a technology platform and serves to transfer the technologies developed at the institute to industry. For this purpose, the centre has high-tech facilities such as a coating system for the production of polymer-based multilayer systems, a low-energy electron accelerator for membrane modification, plasma and ion beam processing systems and ion beam-assisted etching of optical components.
Two other important pieces of equipment were also purchased in 2016/2017: Firstly, a fine ion beam (FIB) system for sample preparation with a focussed ion beam and secondly, a Raman spectrometer, which can be used to carry out investigations into the structure and bonding of materials.On 1 September 2017, Prof. André Anders was appointed Director of the IOM, replacing Prof. Bernd Rauschenbach as Director of the Institute. At the same time, he took over as Head of the Physics Department.
A laboratory for researching plasma deposition processes under vacuum was completed in 2020.
Current research topics
The structure of the IOM was transferred to the current structure with four research areas, three cross-sectional units and the incubator in 2021. The scientific and technological research and development work at the IOM is focussed on four research areas. The aim is to research and develop new surface functionalities for future-oriented fields of application. Each research area is managed independently in organisational terms.
The scientific results of the IOM are published in around 100 publications per year and protected in several patents per year. As is customary in the Leibniz Association, the institute undergoes a comprehensive evaluation every 7 years. Most recently, the IOM received a rating of "very good to excellent" in 2022.
Research topics
Research area 1: Ultra-precision surfaces
This research area focuses on beam-based technologies for ultra-precise processing and shaping of surfaces, near-surface areas and thin films. Micro- and nanostructuring with target specifications down to the sub-nanometre range are possible.
Research area 2: Barrier and precision coatings
This research area examines the production of thin films and coatings at relatively low process temperatures. The basic principles, technologies and applications of these coatings are analysed.
Research area 3: Biocompatible and bioactive surfaces
The research focus lies on the development of new intelligent biomaterials at interfaces and surfaces that enable external controllability/switchability. Tailor-made methods, experiments and modelling are intended to provide a comprehensive basic understanding of physics, which can then be applied in biomedical and bioanalytical contexts.
Research area 4: Surfaces of porous membrane filters
This research area investigates new technologies for the functionalisation and characterisation of porous polymers using radiochemical methods. Membrane-based filtration systems are used in numerous applications such as haemodialysis, water purification and beverage production.
Incubator: Explorative projects
The "Explorative Projects" area currently consists of two working groups: The "Switchable molecular functionalised surfaces" group deals with molecular electronics and spintronics.
The second working group "Surface modification with mass-selected molecular ions" (joint lab with the University of Leipzig) uses preparative mass spectrometry to deposit large molecular ions intact on surfaces.
Cross-section units
The four research areas of the IOM are supported by cross-sectional units with cross-sectional tasks. Each cross-sectional unit is managed independently in organisational terms.
The current cross-section units are:
Modelling and simulation
In this unit, the experimental work within the institute is accompanied and optimised by mathematical models.
Tools
The unit has the task of providing plasma and blasting tools for the work being carried out at the institute, some of which are unique and not commercially available.
Material characterisation and analytical service
The "Materials Characterisation and Analytical Service" cross-sectional unit provides all of the institute's working groups with extensive analytical methods, for example for the characterisation of surfaces or imaging processes.
Research infrastructure large-scale equipment
The IOM has a well-equipped research infrastructure, particularly in the area of large-scale scientific equipment. This includes a Cs-corrected transmission electron microscope in the Leipzig nanoanalytical centre (LenA) and the 10 MeV electron accelerator in the Hertz electron beam laboratory.
Application centre of the IOM (APZ)
One aim is to transfer technological developments from pilot scale to commercial utilisation (scale-up), particularly in the optical and chemical industries, semiconductor technology, mechanical engineering and medical technology.
Spin-off companies & property rights
Several spin-off companies have already been founded on the basis of research results. Numerous industrial property rights such as patents and utility models have also been granted on the basis of research at the IOM. List of industrial property rights at.
Spin-offs:
· IOT – Innovative Oberflächentechnologien GmbH (founded 1998)
· NTG – Neue Technologien GmbH & Co. KG (founded 1999)
· Solarion GmbH (founded 2000, continued as Solarion AG from November 2006, acquired by OC3 AG in 2019)
· Cetelon Nanotechnik GmbH & Co. KG (founded 2001, 2021 taken over by Nanolacke Eilenburg GmbH)
· OPTEG GmbH (founded 2001), 2018 taken over by Bühler Leybold Optcis
· Trionplas Technologies GmbH (founded 2017)
· qCoat GmbH (founded 2019)
Literature
Carsten Bundesmann: Zur Geschichte der Entwicklung und Anwendung von Breitstrahlionenquellen in Leipzig. 2020
External links
Homepage of the Leibniz Institute of Surface Engineering (IOM)
References
Leibniz Association
1992 establishments in Germany
Research institutes established in 1992
Research institutes in Germany
Materials science institutes | Leibniz Institute of Surface Engineering | [
"Materials_science"
] | 2,591 | [
"Materials science organizations",
"Materials science institutes"
] |
76,205,675 | https://en.wikipedia.org/wiki/Momme%20%28unit%29 | is both a Japanese unit of mass and former unit of currency. As a measurement, Momme is part of a table of Japanese units where during the Edo period it was equal to ryō (aka Tael). Since the Meiji era 1 momme has been reformed to equal exactly 3.75 grams in SI units. The latter term for Momme refers to when it was used as a unit of currency during the Edo period in the form of silver coins. As a term, the word "Momme" and its symbol "匁" are unique to Japan. The Chinese equivalent to Momme is qián (), which is also a generic word for "money". While the term Momme is no longer used for currency, it survives as a standard unit of measure used by pearl dealers to communicate with pearl producers and wholesalers.
Origin
The Japanese word Momme first appeared in a family book by the Ōuchi clan during the Bunmei era in 1484. In the English language the word first appears in the early 1700s per the Oxford English Dictionary, which first traces its usage to Johann Jakob Scheuchzer in 1727.
Currency
See also
Tokugawa coinage
1 rin coin
5 rin coin
Notes
References
Currencies of Japan
Economy of the Edo period
Modern obsolete currencies
East Asian units of measurement
Units of mass | Momme (unit) | [
"Physics",
"Mathematics"
] | 270 | [
"Matter",
"Quantity",
"Units of mass",
"Mass",
"Units of measurement"
] |
76,205,678 | https://en.wikipedia.org/wiki/WaLSA%20Team | The Waves in the Lower Solar Atmosphere (WaLSA) team is an international consortium that is focused on investigating wave activity in the Sun's lower atmosphere. The purpose of the group is to understand how magnetohydrodynamic (MHD) waves generated within the Sun's interior and lower atmosphere affect the dynamics and heating of its outer layers.
The WaLSA team's research has been supported by organizations including the Research Council of Norway through the Rosseland Centre for Solar Physics, the Royal Society, and the International Space Science Institute.
Research
The WaLSA team's research focuses on understanding various wave modes propagating through solar structures. They have investigated the coupling mechanisms between different wave modes and measured energy carried by MHD waves.
References
Astrophysics | WaLSA Team | [
"Physics",
"Astronomy"
] | 154 | [
"Astronomical sub-disciplines",
"Astrophysics"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.