title: Sundanese people

text: Sundanese literature was basically oral. Their arts (such as architecture, music, dance, textiles, and ceremonies) substantially preserved traditions from an earlier phase of civilization, stretching back even to the Neolithic, and never overwhelmed (as eastward, in Java) by aristocratic Hindu-Buddhist ideas. The art and culture of Sundanese people reflect historical influences by various cultures that include prehistoric native animism and shamanism traditions, ancient Hindu-Buddhist heritage, and Islamic culture. The Sundanese have very vivid, orally-transmitted memories of the grand era of the Sunda Kingdom. The oral tradition of Sundanese people is called Pantun Sunda, a chant of poetic verses employed for story-telling. It is the counterpart of the Javanese "tembang", similar to but independent from Malay pantun. The Pantun Sunda often recount Sundanese folklore and legends such as Sangkuriang, Lutung Kasarung, Ciung Wanara, Mundinglaya Dikusumah, the tales of King Siliwangi, and popular children's folk stories such as Si Leungli.


title: Sundanese people

text: Traditional Sundanese arts include various forms of music, dance, and martial arts. The most notable types of Sundanese music are angklung bamboo music, kecapi suling music, gamelan degung, reyog Sunda and rampak gendang. The Angklung bamboo musical instrument is considered one of the world heritages of intangible culture.


title: Sundanese people

text: The most well known and distinctive Sundanese dances are Jaipongan, a traditional social dance which is usually, but mistakenly, associated with eroticism. Other popular dances such as the Merak dance describe colourful dancing peafowls. Sisingaan dance is performed mainly in the Subang area to celebrate the circumcision ritual where the boy is seated upon a lion figure carried by four men. Other dances such as the Peafowl dance, Dewi dance and Ratu Graeni dance show Javanese Mataram courtly influences.


title: Sundanese people

text: Wayang golek puppetry is the most popular wayang performance for Sundanese people. Many forms of "kejawen" dance, literature, gamelan music and shadow puppetry ("wayang kulit") derive from the Javanese. Sundanese puppetry is more influenced by Islamic folklore than the influence of Indian epics present in Javanese versions.


title: Sundanese people

text: The Pencak silat martial art in Sundanese tradition can be traced to the historical figure King Siliwangi of the Sunda Pajajaran kingdom, with Cimande as one of the most prominent schools. The recently developed Tarung Derajat is also a popular martial art in West Java. Kujang is the traditional weapon of the Sundanese people.


title: Sundanese people

text: The architecture of a Sundanese house is characterised by its functionality, simplicity, modesty, uniformity with little details, its use of natural thatched materials, and its quite faithful adherence to harmony with nature and the environment.


title: Sundanese people

text: Sundanese traditional houses mostly take basic form of gable roofed structure, commonly called "kampung" style roof, made of thatched materials ("ijuk" black "aren" fibers, "kirai", "hateup" leaves or palm leaves) covering wooden frames and beams, woven bamboo walls, and its structure is built on short stilts. Its roof variations might includes hip and gablet roof (a combination of gable and hip roof).


title: Sundanese people

text: The more elaborate overhanging gablet roof is called "Julang Ngapak", which means "bird spreading wings". Other traditional Sundanese house forms including "Buka Pongpok, Capit Gunting, Jubleg Nangkub, Badak Heuay, Tagog Anjing", and "Perahu Kemureb".


title: Sundanese people

text: Next to houses, rice barn or called "leuit" in Sundanese is also an essential structure in the traditional Sundanese agricultural community. "Leuit" is essential during "Seren Taun" harvest ceremony.


title: Sundanese people

text: Sundanese cuisine is one of the most famous traditional food in Indonesia, and it is also easily found in most Indonesian cities. The Sundanese food is characterised by its freshness; the famous "lalab" (raw vegetables salad) eaten with "sambal" (chili paste), and also "karedok" (peanuts paste) demonstrate the Sundanese fondness for fresh raw vegetables. Similar to other ethnic groups in Indonesia, Sundanese people eat rice for almost every meal. The Sundanese like to say, "If you have not eaten rice, then you have not eaten at all." Rice is prepared in hundreds of different ways. However, it is simple steamed rice that serves as the centrepiece of all meals.


title: Sundanese people

text: Next to steamed rice, the side dishes of vegetables, fish, or meat are added to provide a variety of tastes as well as for protein, mineral and nutrient intake. These side dishes are grilled, fried, steamed or boiled and spiced with any combination of garlic, galangal (a plant of the ginger family), turmeric, coriander, ginger, and lemongrass. The herb-rich food wrapped and cooked inside banana leaf called "pepes" (Sundanese: "pais") is popular among Sundanese people. "Pepes" are available in many varieties according to their ingredients; carp fish, anchovies, minced meat with eggs, mushroom, tofu or oncom. "Oncom" is a fermented peanut-based ingredient that is prevalent within Sundanese cuisine, just like its counterpart, Tempe, which is popular among Javanese people. Usually, the food itself is not too spicy, but it is served with a boiling sauce made by grinding chilli peppers and garlic together. On the coast, saltwater fish are common; in the mountains, fish tend to be either pond-raised carp or goldfish. A well-known Sundanese dish is "lalapan", which consists only of raw vegetables, such as papaya leaves, cucumber, eggplant, and bitter melon.


title: Sundanese people

text: In general, Sundanese food tastes rich and savoury, but not as rich as Padang food, nor as sweet as Javanese food.


title: Sundanese people

text: In Sundanese culture, there is a culture of eating together known as Cucurak in the Bogor area or Munggahan in the Priangan area. This tradition is usually carried out together with extended family or colleagues when approaching Ramadan.


title: Sundanese people

text: The traditional occupation of Sundanese people is agricultural, especially rice cultivation. Sundanese culture and tradition are usually centred around the agricultural cycle. Festivities such as the "Seren Taun" harvest ceremony are held in high importance, especially in the traditional Sundanese community in Ciptagelar village, Cisolok, Sukabumi; Sindang Barang, Pasir Eurih village, Taman Sari, Bogor; and the traditional Sundanese community in Cigugur Kuningan. The typical Sundanese "leuit" (rice barn) is an important part of traditional Sundanese villages; it is held in high esteem as the symbol of wealth and welfare. Since early times, the Sundanese have predominantly been farmers. They tend to be reluctant to be government officers or legislators.


title: Sundanese people

text: Next to agriculture, Sundanese people often choose business and trade to make a living although most are traditional entrepreneurs, such as travelling food or drink vendors, establishing modest "warung" (food stalls) or restaurants, as the vendor of daily consumer's goods or open a modest barber shop. Their affinity for establishing and running small-scale entrepreneurship is most likely contributed by the Sundanese tendency to be independent, carefree, egalitarian, individualistic and optimistic. They seem to abhor the rigid structure and rules of government offices. Several traditional travelling food vendors and food stalls such as "Siomay, Gado-gado" and "Karedok, Nasi Goreng, Cendol, Bubur Ayam, Roti Bakar" (grilled bread), "Bubur kacang hijau" (green beans congee) and Indomie instant noodle stall are notably run by Sundanese.


title: Sundanese people

text: Nevertheless, there are numbers of Sundanese that successfully carved their career as intellectuals or politicians in national politics, government offices and military positions. Some notable Sundanese has gained positions in the Indonesian government as governor, municipal major, vice president and state ministers, also as officers and general in the Indonesian military.


title: Sundanese people

text: Sundanese is also popularly known as cheerful and mercurial folks, as they love to joke and tease around. The wayang golek artform of Cepot, Dawala, and Gareng punakawan characters demonstrate the Sundanese quirky side. Some Sundanese might find art and culture as their passion and become artists, either in fine art, music or performing art. Today, there are several Sundanese involved in the music and entertainment industry, with some of Indonesia's most famous singers, musicians, composers, cinema directors, film and sinetrons (soap opera) actors being of Sundanese origin.


title: Sundanese people

text: Notable Sundanese that has been recognised as Indonesian national heroes include Dewi Sartika that fought for equality for women's education, and statesmen such as Oto Iskandar di Nata and Djuanda Kartawidjaja. Former governor of Jakarta Ali Sadikin, former vice president Umar Wirahadikusumah, and former defence minister Agum Gumelar, and ministers of foreign affairs such as Mochtar Kusumaatmadja, Hassan Wirajuda and Marty Natalegawa, Meutya Hafid are among notable Sundanese in politics. Ajip Rosidi and Achdiat Karta Mihardja are among Indonesian distinguished poets and writers.


title: Sundanese people

text: Today, in the modern Indonesian entertainment industry, there are large numbers of Sundanese artists that have become Indonesia's most famous singers, musicians, composers, cinema directors, film and sinetron actors. Famous dangdut singers Rhoma Irama, Elvy Sukaesih and, musicians and composers such as Erwin Gutawa and singers such as Roekiah, Hetty Koes Endang, Vina Panduwinata, Nicky Astria, Nike Ardilla, Poppy Mercury, Rossa, Gita Gutawa and Syahrini, Indonesian sinetrons actors such as Raffi Ahmad, Jihan Fahira and Asmirandah Zantman, also stunt choreographer, movie action star Kang Cecep Arif Rahman, also film director Nia Dinata, are among artists of Sundanese background. Famous wayang golek puppet master was Asep Sunandar Sunarya, while Sule, Jojon and Kang Ibing are a popular comedians. In sports, Indonesian athletes of Sundanese background include badminton Olympic gold medalists Taufik Hidayat and Ricky Subagja.


title: Stephen Morris (musician)

text: Stephen Paul David Morris (born 28 October 1957) is an English drummer who is best known for his work with the rock band New Order and, previously, Joy Division. He also wrote and performed in The Other Two, a band consisting of Morris and his girlfriend and later wife, Gillian Gilbert. Morris also participated in the New Order spin-off band Bad Lieutenant.


title: Stephen Morris (musician)

text: Stephen Paul David Morris was born on 28 October 1957, in Macclesfield, Cheshire. His father was a travelling salesman who also put on dances. His uncle was a musician. When Morris told his father he wanted to be a drummer, he replied: "Drummers, Stephen. I’ve never met a sane one yet... They all end up taking morphine and drinking absinthe, rotting their brains. You don’t want to end up like that, do you?"


title: Stephen Morris (musician)

text: He attended the King's School, Macclesfield, as did Joy Division singer Ian Curtis. After Joy Division (then called Warsaw) tried three other drummers, they eventually recruited Morris, who responded to a wanted ad posted in a local music shop.


title: Stephen Morris (musician)

text: Morris is noted for his "machine-like" skills as a drummer, which he credits to krautrock influences.


title: Stephen Morris (musician)

text: The drummers he named as musical inspiration, were Jaki Liebezeit of Can and Moe Tucker of the Velvet Underground because they "were the ones who kept it simple". He also cited John French as an influence. From 1977, he was influenced by the music of Siouxsie and the Banshees because their "drummer Kenny Morris played mostly toms"; "hearing the sessions they'd done on John Peel's show and reading gig write-ups", [...] inspired him.


title: Stephen Morris (musician)

text: During Joy Division recording sessions with Martin Hannett, Morris was asked to record his parts one drum at a time so that Hannett could have complete control over the production. He also took an early interest in drum machines, combining them with traditional drumming on many Joy Division and New Order releases. Although he is primarily a percussionist, Morris also plays keyboards and synthesizer.


title: Stephen Morris (musician)

text: Early on, Morris was a contender to become New Order's lead vocalist, and his vocals can be heard on some early live tracks. He also contributed musically to as-yet-unreleased demos by Quando Quango and produced a number of acts with Gilbert for Factory, such as duo Red Turns To..., under New Order's Be Music production tag. He played drums for Echo & the Bunnymen on their rendition of the Doors' "Soul Kitchen", which they recorded at Amazon Studios in Liverpool in 1986.


title: Stephen Morris (musician)

text: During a hiatus from New Order, Morris and Gilbert formed the side project The Other Two; together they have released two albums as well as various remixes and soundtrack work.


title: Stephen Morris (musician)

text: In 2007, Morris and Gilbert remixed two tracks for the Nine Inch Nails remix album "Year Zero Remixed". In June 2009, during New Order's second break-up, band members Bernard Sumner and Phil Cunningham, along with Jake Evans, formed a new band called Bad Lieutenant. Morris recorded drums on several songs with the band, and joined their line-up for live gigs. Bad Lieutenant released their debut album "Never Cry Another Tear" in 2009 and toured from October 2009 to April 2010. They began work on a second album, but are presently on hiatus.


title: Stephen Morris (musician)

text: New Order reformed with a new line-up in September 2011, and Morris returned to playing with New Order.


title: Stephen Morris (musician)

text: In 2019, the book "Record Play Pause", the first volume of his "Confessions of a Post-Punk Percussionist", was published by Constable and later by Little, Brown and Company.


title: Stephen Morris (musician)

text: In 1979, Morris was questioned about the Yorkshire Ripper case. Joy Division's touring schedule happened to be similar to Peter Sutcliffe's movements which led to the police's suspicion. Following gigs in Halifax, Huddersfield, Leeds and Manchester, both Morris and bass player Peter Hook were questioned.


title: Stephen Morris (musician)

text: Morris married fellow New Order member Gillian Gilbert in 1994. The couple live in Rainow, Cheshire, and have two daughters.


title: Stephen Morris (musician)

text: He is science fiction fan, particularly of the TV series "Doctor Who". He has a full-sized Dalek replica in his rehearsal room, which Sumner has called "the sixth member" of New Order. He also owns several military vehicles including a Mark IV Ferret armoured reconnaissance vehicle and several tanks.


title: Adaptation

text: In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection.


title: Adaptation

text: Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin proposed instead that it was explained by natural selection.


title: Adaptation

text: Adaptation is related to biological fitness, which governs the rate of evolution as measured by change in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations that interlock with those of the other species, such as with flowering plants and pollinating insects. In mimicry, species evolve to resemble other species; in Müllerian mimicry this is a mutually beneficial co-evolution as each of a group of strongly defended species (such as wasps able to sting) come to advertise their defenses in the same way. Features evolved for one purpose may be co-opted for a different one, as when the insulating feathers of dinosaurs were co-opted for bird flight.


title: Adaptation

text: Adaptation is a major topic in the philosophy of biology, as it concerns function and purpose (teleology). Some biologists try to avoid terms which imply purpose in adaptation, not least because it suggests a deity's intentions, but others note that adaptation is necessarily purposeful.


title: Adaptation

text: Adaptation is an observable fact of life accepted by philosophers and natural historians from ancient times, independently of their views on evolution, but their explanations differed. Empedocles did not believe that adaptation required a final cause (a purpose), but thought that it "came about naturally, since such things survived." Aristotle did believe in final causes, but assumed that species were fixed.


title: Adaptation

text: In natural theology, adaptation was interpreted as the work of a deity and as evidence for the existence of God. William Paley believed that organisms were perfectly adapted to the lives they led, an argument that shadowed Gottfried Wilhelm Leibniz, who had argued that God had brought about "the best of all possible worlds." Voltaire's satire Dr. Pangloss is a parody of this optimistic idea, and David Hume also argued against design. Charles Darwin broke with the tradition by emphasising the flaws and limitations which occurred in the animal and plant worlds.


title: Adaptation

text: Jean-Baptiste Lamarck proposed a tendency for organisms to become more complex, moving up a ladder of progress, plus "the influence of circumstances," usually expressed as "use and disuse". This second, subsidiary element of his theory is what is now called Lamarckism, a proto-evolutionary hypothesis of the inheritance of acquired characteristics, intended to explain adaptations by natural means.


title: Adaptation

text: Other natural historians, such as Buffon, accepted adaptation, and some also accepted evolution, without voicing their opinions as to the mechanism. This illustrates the real merit of Darwin and Alfred Russel Wallace, and secondary figures such as Henry Walter Bates, for putting forward a mechanism whose significance had only been glimpsed previously. A century later, experimental field studies and breeding experiments by people such as E. B. Ford and Theodosius Dobzhansky produced evidence that natural selection was not only the 'engine' behind adaptation, but was a much stronger force than had previously been thought.


title: Adaptation

text: Adaptation is primarily a process rather than a physical form or part of a body. An internal parasite (such as a liver fluke) can illustrate the distinction: such a parasite may have a very simple bodily structure, but nevertheless the organism is highly adapted to its specific environment. From this we see that adaptation is not just a matter of visible traits: in such parasites critical adaptations take place in the life cycle, which is often quite complex. However, as a practical term, "adaptation" often refers to a "product": those features of a species which result from the process. Many aspects of an animal or plant can be correctly called adaptations, though there are always some features whose function remains in doubt. By using the term "adaptation" for the evolutionary "process", and "adaptive trait" for the bodily part or function (the product), one may distinguish the two different senses of the word.


title: Adaptation

text: Adaptation is one of the two main processes that explain the observed diversity of species, such as the different species of Darwin's finches. The other process is speciation, in which new species arise, typically through reproductive isolation. An example widely used today to study the interplay of adaptation and speciation is the evolution of cichlid fish in African lakes, where the question of reproductive isolation is complex.


title: Adaptation

text: Adaptation is not always a simple matter where the ideal phenotype evolves for a given environment. An organism must be viable at all stages of its development and at all stages of its evolution. This places "constraints" on the evolution of development, behaviour, and structure of organisms. The main constraint, over which there has been much debate, is the requirement that each genetic and phenotypic change during evolution should be relatively small, because developmental systems are so complex and interlinked. However, it is not clear what "relatively small" should mean, for example polyploidy in plants is a reasonably common large genetic change. The origin of eukaryotic endosymbiosis is a more dramatic example.


title: Adaptation

text: All adaptations help organisms survive in their ecological niches. The adaptive traits may be structural, behavioural or physiological. Structural adaptations are physical features of an organism, such as shape, body covering, armament, and internal organization. Behavioural adaptations are inherited systems of behaviour, whether inherited in detail as instincts, or as a neuropsychological capacity for learning. Examples include searching for food, mating, and vocalizations. Physiological adaptations permit the organism to perform special functions such as making venom, secreting slime, and phototropism, but also involve more general functions such as growth and development, temperature regulation, ionic balance and other aspects of homeostasis. Adaptation affects all aspects of the life of an organism.


title: Adaptation

text: Adaptation differs from flexibility, acclimatization, and learning, all of which are changes during life which are not inherited. Flexibility deals with the relative capacity of an organism to maintain itself in different habitats: its degree of specialization. Acclimatization describes automatic physiological adjustments during life; learning means improvement in behavioural performance during life.


title: Adaptation

text: Flexibility stems from phenotypic plasticity, the ability of an organism with a given genotype (genetic type) to change its phenotype (observable characteristics) in response to changes in its habitat, or to move to a different habitat. The degree of flexibility is inherited, and varies between individuals. A highly specialized animal or plant lives only in a well-defined habitat, eats a specific type of food, and cannot survive if its needs are not met. Many herbivores are like this; extreme examples are koalas which depend on "Eucalyptus", and giant pandas which require bamboo. A generalist, on the other hand, eats a range of food, and can survive in many different conditions. Examples are humans, rats, crabs and many carnivores. The "tendency" to behave in a specialized or exploratory manner is inherited—it is an adaptation. Rather different is developmental flexibility: "An animal or plant is developmentally flexible if when it is raised in or transferred to new conditions, it changes in structure so that it is better fitted to survive in the new environment," writes the evolutionary biologist John Maynard Smith.


title: Adaptation

text: If humans move to a higher altitude, respiration and physical exertion become a problem, but after spending time in high altitude conditions they acclimatize to the reduced partial pressure of oxygen, such as by producing more red blood cells. The ability to acclimatize is an adaptation, but the acclimatization itself is not. The reproductive rate declines, but deaths from some tropical diseases also go down. Over a longer period of time, some people are better able to reproduce at high altitudes than others. They contribute more heavily to later generations, and gradually by natural selection the whole population becomes adapted to the new conditions. This has demonstrably occurred, as the observed performance of long-term communities at higher altitude is significantly better than the performance of new arrivals, even when the new arrivals have had time to acclimatize.


title: Adaptation

text: There is a relationship between adaptedness and the concept of fitness used in population genetics. Differences in fitness between genotypes predict the rate of evolution by natural selection. Natural selection changes the relative frequencies of alternative phenotypes, insofar as they are heritable. However, a phenotype with high adaptedness may not have high fitness. Dobzhansky mentioned the example of the Californian redwood, which is highly adapted, but a relict species in danger of extinction. Elliott Sober commented that adaptation was a retrospective concept since it implied something about the history of a trait, whereas fitness predicts a trait's future.


title: Adaptation

text: Sewall Wright proposed that populations occupy "adaptive peaks" on a fitness landscape. To evolve to another, higher peak, a population would first have to pass through a valley of maladaptive intermediate stages, and might be "trapped" on a peak that is not optimally adapted.


title: Adaptation

text: Before Darwin, adaptation was seen as a fixed relationship between an organism and its habitat. It was not appreciated that as the climate changed, so did the habitat; and as the habitat changed, so did the biota. Also, habitats are subject to changes in their biota: for example, invasions of species from other areas. The relative numbers of species in a given habitat are always changing. Change is the rule, though much depends on the speed and degree of the change.


title: Adaptation

text: When the habitat changes, three main things may happen to a resident population: habitat tracking, genetic change or extinction. In fact, all three things may occur in sequence. Of these three effects only genetic change brings about adaptation.


title: Adaptation

text: When a habitat changes, the resident population typically moves to more suitable places; this is the typical response of flying insects or oceanic organisms, which have wide (though not unlimited) opportunity for movement. This common response is called "habitat tracking". It is one explanation put forward for the periods of apparent stasis in the fossil record (the punctuated equilibrium theory).


title: Adaptation

text: Without mutation, the ultimate source of all genetic variation, there would be no genetic changes and no subsequent adaptation through evolution by natural selection. Genetic change occurs in a population when mutation increases or decreases in its initial frequency followed by random genetic drift, migration, recombination or natural selection act on this genetic variation. One example is that the first pathways of enzyme-based metabolism at the very origin of life on Earth may have been co-opted components of the already-existing purine nucleotide metabolism, a metabolic pathway that evolved in an ancient RNA world. The co-option requires new mutations and through natural selection, the population then adapts genetically to its present circumstances. Genetic changes may result in entirely new or gradual change to visible structures, or they may adjust physiological activity in a way that suits the habitat. The varying shapes of the beaks of Darwin's finches, for example, are driven by adaptive mutations in the ALX1 gene. The coat color of different wild mouse species matches their environments, whether black lava or light sand, owing to adaptive mutations in the melanocortin 1 receptor and other melanin pathway genes. Physiological resistance to the heart poisons (cardiac glycosides) that monarch butterflies store in their bodies to protect themselves from predators are driven by adaptive mutations in the target of the poison, the sodium pump, resulting in target site insensitivity. These same adaptive mutations and similar changes at the same amino acid sites were found to evolve in a parallel manner in distantly related insects that feed on the same plants, and even in a bird that feeds on monarchs through convergent evolution, a hallmark of adaptation. Convergence at the gene-level across distantly related species can arise because of evolutionary constraint.


title: Adaptation

text: Habitats and biota do frequently change over time and space. Therefore, it follows that the process of adaptation is never fully complete. Over time, it may happen that the environment changes little, and the species comes to fit its surroundings better and better, resulting in stabilizing selection. On the other hand, it may happen that changes in the environment occur suddenly, and then the species becomes less and less well adapted. The only way for it to climb back up that fitness peak is via the introduction of new genetic variation for natural selection to act upon. Seen like this, adaptation is a genetic "tracking process", which goes on all the time to some extent, but especially when the population cannot or does not move to another, less hostile area. Given enough genetic change, as well as specific demographic conditions, an adaptation may be enough to bring a population back from the brink of extinction in a process called evolutionary rescue. Adaptation does affect, to some extent, every species in a particular ecosystem.


title: Adaptation

text: Leigh Van Valen thought that even in a stable environment, because of antagonistic species interactions and limited resources, a species must constantly had to adapt to maintain its relative standing. This became known as the Red Queen hypothesis, as seen in host-parasite interactions.


title: Adaptation

text: Existing genetic variation and mutation were the traditional sources of material on which natural selection could act. In addition, horizontal gene transfer is possible between organisms in different species, using mechanisms as varied as gene cassettes, plasmids, transposons and viruses such as bacteriophages.


title: Adaptation

text: In coevolution, where the existence of one species is tightly bound up with the life of another species, new or 'improved' adaptations which occur in one species are often followed by the appearance and spread of corresponding features in the other species. In other words, each species triggers reciprocal natural selection in the other. These co-adaptational relationships are intrinsically dynamic, and may continue on a trajectory for millions of years, as has occurred in the relationship between flowering plants and pollinating insects.


title: Adaptation

text: Bates' work on Amazonian butterflies led him to develop the first scientific account of mimicry, especially the kind of mimicry which bears his name: Batesian mimicry. This is the mimicry by a palatable species of an unpalatable or noxious species (the model), gaining a selective advantage as predators avoid the model and therefore also the mimic. Mimicry is thus an anti-predator adaptation. A common example seen in temperate gardens is the hoverfly (Syrphidae), many of which—though bearing no sting—mimic the warning coloration of aculeate Hymenoptera (wasps and bees). Such mimicry does not need to be perfect to improve the survival of the palatable species.


title: Adaptation

text: Bates, Wallace and Fritz Müller believed that Batesian and Müllerian mimicry provided evidence for the action of natural selection, a view which is now standard amongst biologists.


title: Adaptation

text: All adaptations have a downside: horse legs are great for running on grass, but they can't scratch their backs; mammals' hair helps temperature, but offers a niche for ectoparasites; the only flying penguins do is under water. Adaptations serving different functions may be mutually destructive. Compromise and makeshift occur widely, not perfection. Selection pressures pull in different directions, and the adaptation that results is some kind of compromise.


title: Adaptation

text: Consider the antlers of the Irish elk, (often supposed to be far too large; in deer antler size has an allometric relationship to body size). Obviously, antlers serve positively for defence against predators, and to score victories in the annual rut. But they are costly in terms of resources. Their size during the last glacial period presumably depended on the relative gain and loss of reproductive capacity in the population of elks during that time. As another example, camouflage to avoid detection is destroyed when vivid coloration is displayed at mating time. Here the risk to life is counterbalanced by the necessity for reproduction.


title: Adaptation

text: Stream-dwelling salamanders, such as Caucasian salamander or Gold-striped salamander have very slender, long bodies, perfectly adapted to life at the banks of fast small rivers and mountain brooks. Elongated body protects their larvae from being washed out by current. However, elongated body increases risk of desiccation and decreases dispersal ability of the salamanders; it also negatively affects their fecundity. As a result, fire salamander, less perfectly adapted to the mountain brook habitats, is in general more successful, have a higher fecundity and broader geographic range.


title: Adaptation

text: The peacock's ornamental train (grown anew in time for each mating season) is a famous adaptation. It must reduce his maneuverability and flight, and is hugely conspicuous; also, its growth costs food resources. Darwin's explanation of its advantage was in terms of sexual selection: "This depends on the advantage which certain individuals have over other individuals of the same sex and species, in exclusive relation to reproduction." The kind of sexual selection represented by the peacock is called 'mate choice,' with an implication that the process selects the more fit over the less fit, and so has survival value. The recognition of sexual selection was for a long time in abeyance, but has been rehabilitated.


title: Adaptation

text: The conflict between the size of the human foetal brain at birth, (which cannot be larger than about 400 cm, else it will not get through the mother's pelvis) and the size needed for an adult brain (about 1400 cm), means the brain of a newborn child is quite immature. The most vital things in human life (locomotion, speech) just have to wait while the brain grows and matures. That is the result of the birth compromise. Much of the problem comes from our upright bipedal stance, without which our pelvis could be shaped more suitably for birth. Neanderthals had a similar problem.


title: Adaptation

text: As another example, the long neck of a giraffe brings benefits but at a cost. The neck of a giraffe can be up to in length. The benefits are that it can be used for inter-species competition or for foraging on tall trees where shorter herbivores cannot reach. The cost is that a long neck is heavy and adds to the animal's body mass, requiring additional energy to build the neck and to carry its weight around.


title: Adaptation

text: Pre-adaptation occurs when a population has characteristics which by chance are suited for a set of conditions not previously experienced. For example, the polyploid cordgrass "Spartina townsendii" is better adapted than either of its parent species to their own habitat of saline marsh and mud-flats. Among domestic animals, the White Leghorn chicken is markedly more resistant to vitamin B deficiency than other breeds; on a plentiful diet this makes no difference, but on a restricted diet this preadaptation could be decisive.


title: Adaptation

text: Pre-adaptation may arise because a natural population carries a huge quantity of genetic variability. In diploid eukaryotes, this is a consequence of the system of sexual reproduction, where mutant alleles get partially shielded, for example, by genetic dominance. Microorganisms, with their huge populations, also carry a great deal of genetic variability. The first experimental evidence of the pre-adaptive nature of genetic variants in microorganisms was provided by Salvador Luria and Max Delbrück who developed the Fluctuation Test, a method to show the random fluctuation of pre-existing genetic changes that conferred resistance to bacteriophages in "Escherichia coli". The word is controversial because it is teleological and the entire concept of natural selection depends on the presence of genetic variation, regardless of the population size of a species in question.


title: Adaptation

text: Features that now appear as adaptations sometimes arose by co-option of existing traits, evolved for some other purpose. The classic example is the ear ossicles of mammals, which we know from paleontological and embryological evidence originated in the upper and lower jaws and the hyoid bone of their synapsid ancestors, and further back still were part of the gill arches of early fish. The word "exaptation" was coined to cover these common evolutionary shifts in function. The flight feathers of birds evolved from the much earlier feathers of dinosaurs, which might have been used for insulation or for display.


title: Adaptation

text: Animals including earthworms, beavers and humans use some of their adaptations to modify their surroundings, so as to maximize their chances of surviving and reproducing. Beavers create dams and lodges, changing the ecosystems of the valleys around them. Earthworms, as Darwin noted, improve the topsoil in which they live by incorporating organic matter. Humans have constructed extensive civilizations with cities in environments as varied as the Arctic and hot deserts.


title: Adaptation

text: In all three cases, the construction and maintenance of ecological niches helps drive the continued selection of the genes of these animals, in an environment that the animals have modified.


title: Adaptation

text: Some traits do not appear to be adaptive as they have a neutral or deleterious effect on fitness in the current environment. Because genes often have pleiotropic effects, not all traits may be functional: they may be what Stephen Jay Gould and Richard Lewontin called spandrels, features brought about by neighbouring adaptations, on the analogy with the often highly decorated triangular areas between pairs of arches in architecture, which began as functionless features.


title: Adaptation

text: Another possibility is that a trait may have been adaptive at some point in an organism's evolutionary history, but a change in habitats caused what used to be an adaptation to become unnecessary or even maladapted. Such adaptations are termed vestigial. Many organisms have vestigial organs, which are the remnants of fully functional structures in their ancestors. As a result of changes in lifestyle the organs became redundant, and are either not functional or reduced in functionality. Since any structure represents some kind of cost to the general economy of the body, an advantage may accrue from their elimination once they are not functional. Examples: wisdom teeth in humans; the loss of pigment and functional eyes in cave fauna; the loss of structure in endoparasites.


title: Adaptation

text: If a population cannot move or change sufficiently to preserve its long-term viability, then obviously, it will become extinct, at least in that locale. The species may or may not survive in other locales. Species extinction occurs when the death rate over the entire species exceeds the birth rate for a long enough period for the species to disappear. It was an observation of Van Valen that groups of species tend to have a characteristic and fairly regular rate of extinction.


title: Adaptation

text: Just as there is co-adaptation, there is also coextinction, the loss of a species due to the extinction of another with which it is coadapted, as with the extinction of a parasitic insect following the loss of its host, or when a flowering plant loses its pollinator, or when a food chain is disrupted.


title: Adaptation

text: The first stage in the evolution of life on earth is often hypothesized to be the RNA world in which short self-replicating RNA molecules proliferated before the evolution of DNA and proteins. By this hypothesis, life started when RNA chains began to self-replicate, initiating the three mechanisms of Darwinian selection: heritability, variation of type, and competition for resources. The fitness of an RNA replicator (its per capita rate of increase) would likely have been a function of its intrinsic adaptive capacities, determined by its nucleotide sequence, and the availability of resources. The three primary adaptive capacities may have been: (1) replication with moderate fidelity, giving rise to heritability while allowing variation of type, (2) resistance to decay, and (3) acquisition of resources. These adaptive capacities would have been determined by the folded configurations of the RNA replicators resulting from their nucleotide sequences.


title: Adaptation

text: Adaptation raises philosophical issues concerning how biologists speak of function and purpose, as this carries implications of evolutionary history – that a feature evolved by natural selection for a specific reason – and potentially of supernatural intervention – that features and organisms exist because of a deity's conscious intentions. In his biology, Aristotle introduced teleology to describe the adaptedness of organisms, but without accepting the supernatural intention built into Plato's thinking, which Aristotle rejected. Modern biologists continue to face the same difficulty. On the one hand, adaptation is obviously purposeful: natural selection chooses what works and eliminates what does not. On the other hand, biologists by and large reject conscious purpose in evolution. The dilemma gave rise to a famous joke by the evolutionary biologist Haldane: "Teleology is like a mistress to a biologist: he cannot live without her but he's unwilling to be seen with her in public.'" David Hull commented that Haldane's mistress "has become a lawfully wedded wife. Biologists no longer feel obligated to apologize for their use of teleological language; they flaunt it." Ernst Mayr stated that "adaptedness... is "a posteriori" result rather than an a priori goal-seeking", meaning that the question of whether something is an adaptation can only be determined after the event.


title: Himyarite Kingdom

text: The Himyarite Kingdom (, ), or Himyar (, "Ḥimyar", / 𐩹𐩧𐩺𐩵𐩬) (fl. 110 BCE–520s CE), historically referred to as the Homerite Kingdom by the Greeks and the Romans (its subjects being called Homeritae), was a polity in the southern highlands of Yemen, as well as the name of the region which it claimed. Until 110 BCE, it was integrated into the Qatabanian kingdom, afterwards being recognized as an independent kingdom. According to classical sources, their capital was the ancient city of Zafar, relatively near the modern-day city of Sana'a. Himyarite power eventually shifted to Sana'a as the population increased in the fifth century. After the establishment of their kingdom, it was ruled by kings from dhū-Raydān tribe. The kingdom was named Raydān.


title: Himyarite Kingdom

text: The kingdom conquered neighbouring Saba' in c. 25 BCE (for the first time), Qataban in c. 200 CE, and Haḍramaut c. 300 CE. Its political fortunes relative to Saba' changed frequently until it finally conquered the Sabaean Kingdom around 280. Himyar then endured until it finally fell to invaders from the Kingdom of Aksum in 525 CE.


title: Himyarite Kingdom

text: The Himyarites originally worshiped most of the South-Arabian pantheon, including Wadd, ʿAthtar, 'Amm and Almaqah. Since at least the reign of Abikarib Asʿad (c. 384 to 433 CE), Judaism was adopted as the "de facto" state religion. The religion may have been adopted to some extent as much as two centuries earlier, but inscriptions to polytheistic deities ceased after this date. It was embraced initially by the upper classes, and possibly a large proportion of the general population over time.


title: Himyarite Kingdom

text: Descendants of the Himyarites, namely the aristocratic families of Dhu'l-Kala and Dhu Asbah, played a prominent role in early Islamic Syria. They led the South Arabian contingents of the Muslim army during the conquest of Homs in 638 and contributed to making Homs a center for South Arabian settlement, culture and political power. Their chiefs supported Mu'awiya ibn Abi Sufyan against Caliph Ali in the First Muslim Civil War (656–661). Their influence waned with their defeat at the Battle of Marj Rahit against the Quda'a confederation and the Umayyad caliph Marwan I in 684 and practically diminished with the death of their leader at the Battle of Khazir in 686. Nonetheless, members of the Dhu'l-Kala and Dhu Asbah played important roles at different times through the remainder of Umayyad rule (661–750) as governors, commanders, scholars, and pietists.


title: Himyarite Kingdom

text: The Himyarite Kingdom was a confederation of tribes, several inscriptions and monumental buildings survive of this period which shows evidence of a wealthy, sophisticated, relatively literate society that had a rich variety of local gods and religions. Trade was already well established by the 3rd century AD, with Yemen supplying the Roman Empire with frankincense and myrrh. Further, the late 1st century AD writer Pliny the Elder mentioned that the kingdom was "the richest nations in the world". It was a hub of international trade, linking the Mediterranean, the Middle East and India.


title: Himyarite Kingdom

text: The trade linking East Africa with the Mediterranean world largely consisted of exporting ivory from Africa to be sold in the Roman Empire. Ships from Ḥimyar regularly travelled the East African coast, and the state also exerted a large amount of Influence both cultural, religious and political over the trading cities of East Africa whilst the cities of East Africa remained independent. The Periplus of the Erythraean Sea describes the trading empire of Himyar and its ruler "Charibael" (probably Karab'il Watar Yuhan'emII), who is said to have been on friendly terms with Rome:


title: Himyarite Kingdom

text: During this period, the Kingdom of Ḥimyar conquered the kingdoms of Saba' and Qataban and took Raydan/Zafar for its capital instead of Ma'rib; therefore, they have been called Dhu Raydan (). In the early 2nd century AD Saba' and Qataban split from the Kingdom of Ḥimyar; yet in a few decades Qataban was conquered by Hadhramaut (conquered in its turn by Ḥimyar in the 4th century), whereas Saba' was finally conquered by Ḥimyar in the late 3rd century.


title: Himyarite Kingdom

text: Ẓafār's ruins cover scattered over 120 hectare on Mudawwar Mountain 10 km north-north-west of the town of Yarim. Early, Empire and Late/Post art periods have been identified. Around the same time in the north a Himyar General by the name of Nuh Ifriqis led an expedition to Barbaria and took control of eastern ports in modern-day Djibouti. Other Himyarite generals went as far as invading Rhapta in modern-day Mozambique.


title: Himyarite Kingdom

text: By the 4th century, the rich Himyarite export of incense, which had once supplied pagan Rome in its religious offerings, now began to wane with the Christianization of Rome, contributing to a collapse in the local economy.


title: Himyarite Kingdom

text: The Himyarite kings appear to have abandoned polytheism and converted to Judaism around the year 380, several decades after the conversion of the Ethiopian Kingdom of Aksum to Christianity (328). No changes occurred in the people's script, calendar, or language (unlike at Aksum after its conversion). This date marks the end of an era in which numerous inscriptions record the names and deeds of kings, and dedicate buildings to local (e.g. Wagal and Simyada) and major (e.g. Almaqah) gods. From the 380s, temples were abandoned and dedications to the old gods ceased, replaced by references to "Rahmanan", "the Lord of Heaven" or "Lord of Heaven and Earth". The political context for this conversion may have been Arabia's interest in maintaining neutrality and good trade relations with the competing empires of Byzantium, which first adopted Christianity under Theodosius the Great, and the Zoroastrian Sasanian Empire.


title: Himyarite Kingdom

text: One of the first Jewish kings, Tub'a Abu Kariba As'ad (r. 390–420), is believed to have converted following a military expedition into northern Arabia in an effort to eliminate Byzantine influence. The Byzantine emperors had long eyed the Arabian Peninsula and sought to control the lucrative spice trade and route to India. The Byzantines hoped to establish a protectorate by converting the inhabitants to Christianity. Some progress had been made in northern Arabia but they had little success in Ḥimyar.


title: Himyarite Kingdom

text: Abu-Kariba's forces reached Yathrib and, meeting no resistance, they passed through the city, leaving the king's son behind as governor. Abu-Kariba soon received news that the people of Yathrib had killed his son. He turned back in order to wreak vengeance on the city. After cutting down the palm trees from which the inhabitants derived their main income, he laid siege to the city. The Jews of Yathrib fought side by side with their pagan neighbors.


title: Himyarite Kingdom

text: During the siege Abu-Kariba fell severely ill. Two Jewish scholars in Yathrib, Ka'ab and Asad by name, called on the king in his camp and used their knowledge of medicine to restore him to health. While attending the king, they pleaded with him to lift the siege and make peace. The sages' appeal is said to have persuaded Abu-Kariba; he called off his attack and also embraced Judaism along with his entire army. At his insistence, the two Jewish scholars accompanied the Ḥimyarite king back to his capital, where he demanded that all his people convert to Judaism. Initially, there was great resistance. After an ordeal had justified the king's demand and confirmed the truth of the Jewish faith, many Himyarites supported Judaism. Some historians argue that the people were not motivated by politics, but that Judaism, by its philosophical, simplistic, and austere nature, was attractive to the nature of the Semitic people.


title: Himyarite Kingdom

text: Abu-Kariba continued to engage in military campaigns and met his death under unclear circumstances. Some scholars believe that his own soldiers killed him. He left three sons, Ḥasan, 'Amru, and Zorah, all of whom were minors at the time. After Abu-Kariba's demise, a pagan named Dhū-Shanatir seized the throne. In the reign of Subahbi'il Yakkaf, Azqir, the son of Abu Karib Assad and serving as a Christian missionary from Najrān, was put to death after he had erected a chapel with a cross. Christian sources interpret the event as a martyrdom at Jewish hands: the site for his execution, Najrān, was said to have been chosen on the advice of a rabbi, but indigenous sources do not mention persecutions on the grounds of faith. His death may have been intended to deter the extension of Byzantine influence.


title: Himyarite Kingdom

text: The first Aksumite invasion took place sometime in the 5th century and was triggered by the persecution of Christians. Two Christian sources, including the "Zuqnin Chronicle" once attributed to Dionysius I Telmaharoyo, which was written more than three centuries later, say that the Himyarite king prompted the killings by stating, "This is because in the countries of the Romans the Christians wickedly harass the Jews who live in their countries and kill many of them. Therefore I am putting these men to death." In retaliation the Aksumites invaded the land and thereafter established a bishopric and built Christian churches in Zafar.


title: Himyarite Kingdom

text: The kingdom maintained nominal control of Arabia until 525. A severe drought in the 6th century weakened the Himyarite kingdom and contributed to its eventual conquest by Aksum.


title: Himyarite Kingdom

text: The Jewish monarchy in Ḥimyar ended with the reign of Yṳsuf, known as Dhū Nuwās, who, in 523, persecuted the Himyarite Christian population of Najrān. By the year 500, on the eve of the regency of Marthad'īlān Yanūf (c. 500–515) the kingdom of Himyar exercised control over much of the Arabian peninsula. It was during his reign that the Himyarite kingdom began to become a tributary state of Aksum, the process concluding by the time of the reign of Ma'dīkarib Yafur (519–522), a Christian appointed by the Aksumites.


title: Himyarite Kingdom

text: A coup d'état ensued, with Dhu Nuwas, who had attempted to overthrow the dynasty several years earlier, assuming authority after killing the Aksumite garrison in Zafār. He proceeded to engage the Ethiopian guards, and their Christian allies in the Tihāma coastal lowlands facing Abyssinia. After taking the port of Mukhawān, where he burnt down the local church, he advanced south as far as the fortress of Maddabān overlooking the Bab-el-Mandeb, where he expected Kaleb Ella Aṣbeḥa to land his fleet. The campaign eventually killed between 11,500 and 14,000, and took a similar number of prisoners. Mukhawān became his base, while he dispatched one of his generals, a Jewish prince named Sharaḥ'īl Yaqbul dhu Yaz'an, against Najrān, a predominantly Christian oasis, with a good number of Jews, who had supported with troops his earlier rebellion, but refused to recognize his authority after the massacre of the Aksumite garrison. The general blocked the caravan route connecting Najrān with Eastern Arabia.


title: Himyarite Kingdom

text: During this period, references to pagan gods disappeared from royal inscriptions and texts on public buildings, and were replaced by references to a single deity. Inscriptions in the Sabean language, and sometimes Hebrew, called this deity "Rahman" (the Merciful), “Lord of the Heavens and Earth,” the “God of Israel” and “Lord of the Jews”. Prayers invoking Rahman's blessings on the “people of Israel” often ended with the Hebrew words "shalom" and "amen".


title: Himyarite Kingdom

text: There is evidence that the solar goddess Shams was especially favoured in Himyar, being the national goddess and possibly an ancestral deity.


title: Himyarite Kingdom

text: As the Byzantines were usually equipped with such of horses armour, Indian fenestrated battle axe, round shield, spear, and scale or mail armour, Paul Yule presumed the Himyarite soldiers armed in comparable fashion, if not systematically as such.


title: Himyarite Kingdom

text: It is a matter of debate whether the Ṣayhadic Himyarite language was spoken in the south-western Arabian peninsula until the 10th century. The few 'Himyarite' texts seem to be rhymed.


title: Himyarite Kingdom

text: After the spread of Islam in Yemen, Himyarite noble families were able to re-establish control over parts of Yemen.


title: Himyarite Kingdom

text: Many Himyarites participated in the Muslim conquest of Syria in the 630s and, along with other South Arabian tribes, settled in city of Homs after its capture in 637. The city became the center of these tribes in Islamic Syria, which served as the center of the Caliphate during Umayyad rule (661–750). The two principal Himyarite families that established themselves in Homs were the Dhu Asbah and Dhu'l-Kala. The latter had been the most influential family in South Arabia before the advent of Islam there.


title: Himyarite Kingdom

text: Among the leaders of the conquering Muslim troops was the Himyarite prince Samayfa ibn Nakur of the Dhu'l-Kala. The Asbah chief Kurayb ibn Abraha Abu Rishdin led the Himyar of Homs, but he later moved to Egypt with most of the Dhu Asbah. Members of that family, Abraha ibn Sabbah and his son Abu Shamir, had participated in the Muslim conquest of Egypt in 640–641. Samayfa was another dominant figure of the city and was referred to in the early Muslim sources as the "king of Himyar". During the governorship of Syria by Mu'awiya ibn Abi Sufyan (640s–661), the Himyarites supported him against Caliph Ali () during the First Muslim Civil War. At the Battle of Siffin with Ali in 657, Samayfa led the Homs contingent in Mu'awiya's army and was slain. He was succeeded by his son Shurahbil as the power-broker of the Homs tribesmen.


title: Himyarite Kingdom

text: According to the historian Werner Caskel, the Himyar and the other South Arabian tribes of Homs, including the Hamdan, formed a confederation called after their supposed ancestor Qahtan in opposition to the Quda'a confederation, whose constituent tribes had long resided in Syria before the advent of Islam. To the chagrin of the South Arabians in Homs and the Qays tribes of northern Syria, the Quda'a, led by the Banu Kalb tribe, held the supreme position among the tribal groups in the courts of the first Umayyad caliphs Mu'awiya ibn Abi Sufyan () and Yazid I (). With the strong presence of the Himyarite elite and South Arabian tribesmen in Homs, their scholars there developed and propagated an ideology of Qahtanite preeminence that sought to compete with the elite groups of Islam, including the Quraysh, whose members held the office of the caliph. To that end, they composed and transmitted narratives of the pre-Islamic South Arabian kingdoms, including war stories of these kings' far-flung conquests and heroics and tales of their wealth.


title: Himyarite Kingdom

text: After the deaths of Yazid I and his son and successor Mu'awiya II in 683 and 684, respectively, the Qahtan and the Qays backed the rival caliphate of Abd Allah ibn al-Zubayr, who was based in Mecca, while the Quda'a supported the candidacy of the Umayyad Marwan I. Kurayb ibn Abraha also backed Ibn al-Zubayr in Egypt. The Qahtan joined Ibn al-Zubayr's representative in Syria, Dahhak ibn Qays al-Fihri, in the Battle of Marj Rahit against Marwan and the Quda'a in 684. The latter decisively won that battle. Afterward, Dahhak's commander in Homs, Nu'man ibn Bashir al-Ansari, was tracked down and killed by the Dhu'l-Kala. A member of the family who had served as the head of Yazid I's "shurta" (select troops), Khalid ibn Ma'dan ibn Abi Karib, decapitated Nu'man and sent his head to Marwan I. Not long after Marj Rahit, Qahtan and Quda'a reconciled under unclear circumstances and formed the super-tribal group of the Yaman in alliance against the Qays. The resulting Qays–Yaman rivalry for political power and privilege persisted through the remainder of Umayyad rule.


title: Himyarite Kingdom

text: In 686 Shurahbil ibn Dhi'l-Kala, the leader of the Himyar in Syria, was slain commanding his troops in the Umayyad army at the Battle of Khazir. As a consequence, the Himyar in Homs "sank to military insignificance", according to the historian Wilferd Madelung. Khalid ibn Ma'dan maintained his position of prestige with the Umayyad dynasty and Syrian Muslim society in general, having shifted to a new role as a prominent Muslim scholar. Kurayb's cousin Ayyub ibn Shurahbil ibn Sabbah served as the governor of Egypt under Caliph Umar II (), while a Dhu'l-Kala member, Imran ibn al-Nu'man, served as the Caliph's governor of Sind.


title: Himyarite Kingdom

text: During the Third Muslim Civil War, the Dhu Asbah tribesmen who had remained in South Arabia are recorded among the supporters of the Kharijite leader Abu Hamza. A possible member of the family in Syria, Nadr ibn Yarim, led a summertime military expedition against the Byzantines under the Abbasid caliph al-Saffah ().


title: Himyarite Kingdom

text: Kahlan septs emigrated from Yemen to dwell in the different parts of the Arabian Peninsula prior to the Great Flood (Sail Al-‘Arim of Marib Dam), due to the failure of trade under the Roman pressure and domain on both sea and land trade routes following Roman occupation of Egypt and Syria.


title: Himyarite Kingdom

text: Another tribe of Himyar, known as Banū Quḑā'ah, also left Yemen and dwelt in Samāwah on the borders of Iraq.


title: Himyarite Kingdom

text: However, it is estimated that the majority of the Ḥimyar Christian royalty migrated into Jordan, Al-Karak, where initially they were known as Banū Ḥimyar (Sons of Ḥimyar). Many later on moved to central Jordan


title: Dux

text: Dux (; plural: "ducēs") is Latin for "leader" (from the noun "dux, ducis", "leader, general") and later for duke and its variant forms (doge, duce, etc.). During the Roman Republic and for the first centuries of the Roman Empire, "dux" could refer to anyone who commanded troops, both Roman generals and foreign leaders, but was not a formal military rank.


title: Dux

text: Until the 3rd century, "dux" was not a formal expression of rank within the Roman military or administrative hierarchy.


title: Dux

text: In the Roman army, a "dux" would be a general in charge of two or more legions. While the title of "dux" could refer to a consul or imperator, it usually refers to the Roman governor of the provinces. As the governor, the dux was both the highest civil official as well as the commander-in-chief of the legions garrisoned within the province.


title: Dux

text: In writing his commentaries on the Gallic Wars, Julius Caesar uses the term only for Celtic generals, with one exception for a Roman commander who held no official rank.


title: Dux

text: By the mid-3rd century AD, it had acquired a more precise connotation defining the commander of an expeditionary force, usually made up of detachments (i.e., "vexillationes") from one or more of the regular military formations. Such appointments were made to deal with specific military situations when the threat to be countered seemed beyond the capabilities of the province-based military command structure that had characterised the Roman army of the High Empire.


title: Dux

text: From the time of Gallienus onwards for more than a century were invariably "Viri Perfectissimi", i.e., members of the second class of the equestrian order. Thus, they would have out-ranked the commanders of provincial legions, who were usually "Viri Egregii" – equestrians of the third class.


title: Dux

text: "Duces" differed from "praesides" who were the supreme civil as well as military authority within their provinces in that the function of the former was purely military. However, the military authority of a "dux" was not necessarily confined to a single province and they do not seem to have been subject to the authority of the governor of the province in which they happened to be operating. It was not until the end of the 3rd century that the term "dux" emerged as a regular military rank held by a senior officer of "limitanei" – i.e. frontier troops as opposed those attached to an Imperial field-army ("comitatenses") – with a defined geographic area of responsibility.


title: Dux

text: During the time of the Dominate, the powers of a "dux" were split from the role of the governor and were given to a new office called "dux". The dux was now the highest military office within the province and commanded the legions, but the governor had to authorize the use of the "dux"'s powers. However, once those powers were authorized, the "dux" could act independently from the governor and handle all military matters. The "Dux Belgicae secundae" ("commander of the second Belgic province") is an example of this office.


title: Dux

text: After Diocletian's Tetrarchy reform, the provinces were organized into dioceses with each dioceses administered by a vicarius. As with the governors, the vicarius was assisted by a "dux". This "dux" was superior to all other "duces" within the dioceses—when the vicarius called the legions of the dioceses into action, all of the legions were at the command of the "dux". The office of "dux" was, in turn, made subject to the magister militum of his respective praetorian prefecture, and above him to the emperor. The "Dux per Gallias", "dux" of the diocese of Gaul, is an example of this office.


title: Dux

text: In the Byzantine era of the Roman Empire, the position of dux survived (Byzantine Greek: "δούξ", "doux", plural "δούκες", "doukes") as a rank equivalent to a general ("strategos"). In the late 10th and early 11th centuries, a "doux" or "katepano" was in charge of large circumscriptions consisting of several smaller "themata" and of the professional regiments ("tagmata") of the Byzantine army (as opposed to the largely militia-like forces of most "themata"). In the Komnenian period, the title of "doux" replaced altogether the "strategos" in designating the military official in charge of a "thema". In the Byzantine navy, "doukes" of the fleet appear in the 1070s, and the office of "megas doux" ("grand duke") was created in the 1090s as the commander-in-chief of the entire navy.


title: Dux

text: The title also gave rise to a family name, the aristocratic Doukas clan, which in the 9th–11th centuries provided several Byzantine emperors and generals, while later bearers of the name (maternally descended from the original family) founded the Despotate of Epirus in northwestern Greece.


title: Dux

text: King Arthur, in one of his earliest literary appearances, is described as "dux bellorum" (""dux" of battles") among the kings of the Romano-Britons in their wars against the Anglo-Saxons. A chronicle from St Martin's monastery in Cologne states that the monastery had been pillaged by the Saxons in 778, but that it was rebuilt by an "Olgerus, dux Daniæ" (who may have been the historical person around whom the myth of Ogier the Dane formed), with the help of Charlemagne.


title: Dux

text: "Dux" is also the root of various high feudal noble titles of peerage rank, such as the English "duke", the French "duc", the Spanish and Portuguese "duque", the Venetian "doge", the Italian "duca" and "duce", and the Byzantine Greek "dukas" or "doukas" (Gr. δούκας) (see Doukas).


title: Dux

text: Italian Fascist dictator Benito Mussolini used the title of "dux" (and "duce" in Italian) to represent his leadership. One fascist motto was "DVX MEA LVX", Latin for "[The] Duce [is] my light" or "[The] Leader [is] my light".


title: Soil liquefaction

text: Soil liquefaction occurs when a cohesionless saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress such as shaking during an earthquake or other sudden change in stress condition, in which material that is ordinarily a solid behaves like a liquid. In soil mechanics, the term "liquefied" was first used by Allen Hazen in reference to the 1918 failure of the Calaveras Dam in California. He described the mechanism of flow liquefaction of the embankment dam as:


title: Soil liquefaction

text: The phenomenon is most often observed in saturated, loose (low density or uncompacted), sandy soils. This is because a loose sand has a tendency to compress when a load is applied. Dense sands, by contrast, tend to expand in volume or 'dilate'. If the soil is saturated by water, a condition that often exists when the soil is below the water table or sea level, then water fills the gaps between soil grains ('pore spaces'). In response to soil compressing, the pore water pressure increases and the water attempts to flow out from the soil to zones of low pressure (usually upward towards the ground surface). However, if the loading is rapidly applied and large enough, or is repeated many times (e.g. earthquake shaking, storm wave loading) such that the water does not flow out before the next cycle of load is applied, the water pressures may build to the extent that it exceeds the force (contact stresses) between the grains of soil that keep them in contact. These contacts between grains are the means by which the weight from buildings and overlying soil layers is transferred from the ground surface to layers of soil or rock at greater depths. This loss of soil structure causes it to lose its strength (the ability to transfer shear stress), and it may be observed to flow like a liquid (hence 'liquefaction').


title: Soil liquefaction

text: Although the effects of soil liquefaction have been long understood, engineers took more notice after the 1964 Alaska earthquake and 1964 Niigata earthquake. It was a major factor in the destruction in San Francisco's Marina District during the 1989 Loma Prieta earthquake, and in the Port of Kobe during the 1995 Great Hanshin earthquake. More recently soil liquefaction was largely responsible for extensive damage to residential properties in the eastern suburbs and satellite townships of Christchurch during the 2010 Canterbury earthquake and more extensively again following the Christchurch earthquakes that followed in early and mid-2011. On 28 September 2018, an earthquake of 7.5 magnitude hit the Central Sulawesi province of Indonesia. Resulting soil liquefaction buried the suburb of Balaroa and Petobo village in 3 meters deep mud. The government of Indonesia is considering designating the two neighborhoods of Balaroa and Petobo, that have been totally buried under mud, as mass graves.


title: Soil liquefaction

text: The building codes in many countries require engineers to consider the effects of soil liquefaction in the design of new buildings and infrastructure such as bridges, embankment dams and retaining structures.


title: Soil liquefaction

text: Soil liquefaction occurs when the effective stress (shear strength) of soil is reduced to essentially zero. This may be initiated by either monotonic loading (i.e. a single, sudden occurrence of a change in stress – examples include an increase in load on an embankment or sudden loss of toe support) or cyclic loading (i.e. repeated changes in stress condition – examples include wave loading or earthquake shaking). In both cases a soil in a saturated loose state, and one which may generate significant pore water pressure on a change in load are the most likely to liquefy. This is because loose soil has the tendency to compress when sheared, generating large excess porewater pressure as load is transferred from the soil skeleton to adjacent pore water during undrained loading. As pore water pressure rises, a progressive loss of strength of the soil occurs as effective stress is reduced.


title: Soil liquefaction

text: Liquefaction is more likely to occur in sandy or non-plastic silty soils, but may in rare cases occur in gravels and clays (see quick clay).


title: Soil liquefaction

text: A 'flow failure' may initiate if the strength of the soil is reduced below the stresses required to maintain the equilibrium of a slope or footing of a structure. This can occur due to monotonic loading or cyclic loading, and can be sudden and catastrophic. A historical example is the Aberfan disaster. Casagrande referred to this type of phenomena as 'flow liquefaction' although a state of zero effective stress is not required for this to occur.


title: Soil liquefaction

text: 'Cyclic liquefaction' is the state of soil when large shear strains have accumulated in response to cyclic loading. A typical reference strain for the approximate occurrence of zero effective stress is 5% double amplitude shear strain. This is a soil test-based definition, usually performed via cyclic triaxial, cyclic direct simple shear, or cyclic torsional shear type apparatus. These tests are performed to determine a soil's resistance to liquefaction by observing the number of cycles of loading at a particular shear stress amplitude required to induce 'fails'. Failure here is defined by the aforementioned shear strain criteria.


title: Soil liquefaction

text: The term 'cyclic mobility' refers to the mechanism of progressive reduction of effective stress due to cyclic loading. This may occur in all soil types including dense soils. However, on reaching a state of zero effective stress such soils immediately dilate and regain strength. Thus, shear strains are significantly less than a true state of soil liquefaction.


title: Soil liquefaction

text: Liquefaction is more likely to occur in loose to moderately saturated granular soils with poor drainage, such as silty sands or sands and gravels containing impermeable sediments. During wave loading, usually cyclic undrained loading, e.g. seismic loading, loose sands tend to decrease in volume, which produces an increase in their pore water pressures and consequently a decrease in shear strength, i.e. reduction in effective stress.


title: Soil liquefaction

text: Deposits most susceptible to liquefaction are young (Holocene-age, deposited within the last 10,000 years) sands and silts of similar grain size (well-sorted), in beds at least metres thick, and saturated with water. Such deposits are often found along stream beds, beaches, dunes, and areas where windblown silt (loess) and sand have accumulated. Examples of soil liquefaction include quicksand, quick clay, turbidity currents and earthquake-induced liquefaction.


title: Soil liquefaction

text: Depending on the initial void ratio, the soil material can respond to loading either strain-softening or strain-hardening. Strain-softened soils, e.g. loose sands, can be triggered to collapse, either monotonically or cyclically, if the static shear stress is greater than the ultimate or steady-state shear strength of the soil. In this case "flow liquefaction" occurs, where the soil deforms at a low constant residual shear stress. If the soil strain-hardens, e.g. moderately dense to dense sand, flow liquefaction will generally not occur. However, cyclic softening can occur due to cyclic undrained loading, e.g. earthquake loading. Deformation during cyclic loading depends on the density of the soil, the magnitude and duration of the cyclic loading, and amount of shear stress reversal. If stress reversal occurs, the effective shear stress could reach zero, allowing cyclic liquefaction to take place. If stress reversal does not occur, zero effective stress cannot occur, and cyclic mobility takes place.


title: Soil liquefaction

text: The resistance of the cohesionless soil to liquefaction will depend on the density of the soil, confining stresses, soil structure (fabric, age and cementation), the magnitude and duration of the cyclic loading, and the extent to which shear stress reversal occurs.


title: Soil liquefaction

text: Three parameters are needed to assess liquefaction potential using the "simplified empirical method":


title: Soil liquefaction

text: Pressures generated during large earthquakes can force underground water and liquefied sand to the surface. This can be observed at the surface as effects known alternatively as "sand boils", "sand blows" or "sand volcanoes". Such earthquake ground deformations can be categorized as primary deformation if located on or close to the ruptured fault, or distributed deformation if located at considerable distance from the ruptured fault.


title: Soil liquefaction

text: The other common observation is land instability – cracking and movement of the ground down slope or towards unsupported margins of rivers, streams, or the coast. The failure of ground in this manner is called 'lateral spreading', and may occur on very shallow slopes with angles only 1 or 2 degrees from the horizontal.


title: Soil liquefaction

text: One positive aspect of soil liquefaction is the tendency for the effects of earthquake shaking to be significantly damped (reduced) for the remainder of the earthquake. This is because liquids do not support a shear stress and so once the soil liquefies due to shaking, subsequent earthquake shaking (transferred through ground by shear waves) is not transferred to buildings at the ground surface.


title: Soil liquefaction

text: Studies of liquefaction features left by prehistoric earthquakes, called paleoliquefaction or paleoseismology, can reveal information about earthquakes that occurred before records were kept or accurate measurements could be taken.


title: Soil liquefaction

text: The effects of soil liquefaction on the built environment can be extremely damaging. Buildings whose foundations bear directly on sand which liquefies will experience a sudden loss of support, which will result in drastic and irregular settlement of the building causing structural damage, including cracking of foundations and damage to the building structure, or leaving the structure unserviceable, even without structural damage. Where a thin crust of non-liquefied soil exists between building foundation and liquefied soil, a 'punching shear' type foundation failure may occur. Irregular settlement may break underground utility lines. The upward pressure applied by the movement of liquefied soil through the crust layer can crack weak foundation slabs and enter buildings through service ducts, and may allow water to damage building contents and electrical services.


title: Soil liquefaction

text: Bridges and large buildings constructed on pile foundations may lose support from the adjacent soil and buckle, or come to rest at a tilt.


title: Soil liquefaction

text: Sloping ground and ground next to rivers and lakes may slide on a liquefied soil layer (termed 'lateral spreading'), opening large ground fissures, and can cause significant damage to buildings, bridges, roads and services such as water, natural gas, sewerage, power and telecommunications installed in the affected ground. Buried tanks and manholes may float in the liquefied soil due to buoyancy. Earth embankments such as flood levees and earth dams may lose stability or collapse if the material comprising the embankment or its foundation liquefies.


title: Soil liquefaction

text: Over geological time, liquefaction of soil material due to earthquakes could provide a dense parent material in which the fragipan may develop through pedogenesis.


title: Soil liquefaction

text: Mitigation methods have been devised by earthquake engineers and include various soil compaction techniques such as vibro compaction (compaction of the soil by depth vibrators), dynamic compaction, and vibro stone columns. These methods densify soil and enable buildings to avoid soil liquefaction.


title: Soil liquefaction

text: Existing buildings can be mitigated by injecting grout into the soil to stabilize the layer of soil that is subject to liquefaction. Another method called IPS (Induced Partial Saturation) is now practicable to apply on larger scale. In this method, the saturation degree of the soil is decreased.


title: Soil liquefaction

text: Quicksand forms when water saturates an area of loose sand and the sand is agitated. When the water trapped in the batch of sand cannot escape, it creates liquefied soil that can no longer resist force. Quicksand can be formed by standing or (upwards) flowing underground water (as from an underground spring), or by earthquakes. In the case of flowing underground water, the force of the water flow opposes the force of gravity, causing the granules of sand to be more buoyant. In the case of earthquakes, the shaking force can increase the pressure of shallow groundwater, liquefying sand and silt deposits. In both cases, the liquefied surface loses strength, causing buildings or other objects on that surface to sink or fall over.


title: Soil liquefaction

text: The saturated sediment may appear quite solid until a change in pressure or a shock initiates the liquefaction, causing the sand to form a suspension with each grain surrounded by a thin film of water. This cushioning gives quicksand, and other liquefied sediments, a spongy, fluidlike texture. Objects in the liquefied sand sink to the level at which the weight of the object is equal to the weight of the displaced sand/water mix and the object "floats" due to its buoyancy.


title: Soil liquefaction

text: Quick clay, known as "Leda Clay" in Canada, is a water-saturated gel, which in its solid form resembles highly sensitive clay. This clay has a tendency to change from a relatively stiff condition to a liquid mass when it is disturbed. This gradual change in appearance from solid to liquid is a process known as spontaneous liquefaction. The clay retains a solid structure despite its high water content (up to 80% by volume), because surface tension holds water-coated flakes of clay together. When the structure is broken by a shock or sufficient shear, it enters a fluid state.


title: Soil liquefaction

text: Quick clay is found only in northern countries such as Russia, Canada, Alaska in the U.S., Norway, Sweden and Finland, which were glaciated during the Pleistocene epoch.


title: Soil liquefaction

text: Quick clay has been the underlying cause of many deadly landslides. In Canada alone, it has been associated with more than 250 mapped landslides. Some of these are ancient, and may have been triggered by earthquakes.


title: Soil liquefaction

text: Submarine landslides are turbidity currents and consist of water-saturated sediments flowing downslope. An example occurred during the 1929 Grand Banks earthquake that struck the continental slope off the coast of Newfoundland. Minutes later, transatlantic telephone cables began breaking sequentially, farther and farther downslope, away from the epicenter. Twelve cables were snapped in a total of 28 places. Exact times and locations were recorded for each break. Investigators suggested that a 60-mile-per-hour (100 km/h) submarine landslide or turbidity current of water-saturated sediments swept 400 miles (600 km) down the continental slope from the earthquake's epicenter, snapping the cables as it passed.


title: Micro black hole

text: Micro black holes, also called mini black holes or quantum mechanical black holes, are hypothetical tiny (<1 ) black holes, for which quantum mechanical effects play an important role. The concept that black holes may exist that are smaller than stellar mass was introduced in 1971 by Stephen Hawking.


title: Micro black hole

text: It is possible that such black holes were created in the high-density environment of the early Universe (or Big Bang), or possibly through subsequent phase transitions (referred to as primordial black holes). They might be observed by astrophysicists through the particles they are expected to emit by Hawking radiation.


title: Micro black hole

text: Some hypotheses involving additional space dimensions predict that micro black holes could be formed at energies as low as the TeV range, which are available in particle accelerators such as the Large Hadron Collider. Popular concerns have then been raised over end-of-the-world scenarios (see Safety of particle collisions at the Large Hadron Collider). However, such quantum black holes would instantly evaporate, either totally or leaving only a very weakly interacting residue. Beside the theoretical arguments, cosmic rays hitting the Earth do not produce any damage, although they reach energies in the range of hundreds of TeV.


title: Micro black hole

text: In an early speculation, Stephen Hawking conjectured that a black hole would not form with a mass below about (roughly the Planck mass). To make a black hole, one must concentrate mass or energy sufficiently that the escape velocity from the region in which it is concentrated exceeds the speed of light.


title: Micro black hole

text: Some extensions of present physics posit the existence of extra dimensions of space. In higher-dimensional spacetime, the strength of gravity increases more rapidly with decreasing distance than in three dimensions. With certain special configurations of the extra dimensions, this effect can lower the Planck scale to the TeV range. Examples of such extensions include large extra dimensions, special cases of the Randall–Sundrum model, and string theory configurations like the GKP solutions. In such scenarios, black hole production could possibly be an important and observable effect at the Large Hadron Collider (LHC).


title: Micro black hole

text: All this assumes that the theory of general relativity remains valid at these small distances. If it does not, then other, currently unknown, effects might limit the minimum size of a black hole. Elementary particles are equipped with a quantum-mechanical, intrinsic angular momentum (spin). The correct conservation law for the total (orbital plus spin) angular momentum of matter in curved spacetime requires that spacetime is equipped with torsion. The simplest and most natural theory of gravity with torsion is the Einstein–Cartan theory. Torsion modifies the Dirac equation in the presence of the gravitational field and causes fermion particles to be spatially extended. In this case the spatial extension of fermions limits the minimum mass of a black hole to be on the order of , showing that micro black holes may not exist. The energy necessary to produce such a black hole is 39 orders of magnitude greater than the energies available at the Large Hadron Collider, indicating that the LHC cannot produce mini black holes. But if black holes are produced, then the theory of general relativity is proven wrong and does not exist at these small distances. The rules of general relativity would be broken, as is consistent with theories of how matter, space, and time break down around the event horizon of a black hole. This would prove the spatial extensions of the fermion limits to be incorrect as well. The fermion limits assume a minimum mass needed to sustain a black hole, as opposed to the opposite, the minimum mass needed to start a black hole, which in theory is achievable in the LHC under some conditions.


title: Micro black hole

text: In 1975, Stephen Hawking argued that, due to quantum effects, black holes "evaporate" by a process now referred to as Hawking radiation in which elementary particles (such as photons, electrons, quarks and gluons) are emitted. His calculations showed that the smaller the size of the black hole, the faster the evaporation rate, resulting in a sudden burst of particles as the micro black hole suddenly explodes.


title: Micro black hole

text: Any primordial black hole of sufficiently low mass will evaporate to near the Planck mass within the lifetime of the Universe. In this process, these small black holes radiate away matter. A rough picture of this is that pairs of virtual particles emerge from the vacuum near the event horizon, with one member of a pair being captured, and the other escaping the vicinity of the black hole. The net result is the black hole loses mass (due to conservation of energy). According to the formulae of black hole thermodynamics, the more the black hole loses mass, the hotter it becomes, and the faster it evaporates, until it approaches the Planck mass. At this stage, a black hole would have a Hawking temperature of (), which means an emitted Hawking particle would have an energy comparable to the mass of the black hole. Thus, a thermodynamic description breaks down. Such a micro black hole would also have an entropy of only 4 nats, approximately the minimum possible value. At this point then, the object can no longer be described as a classical black hole, and Hawking's calculations also break down.


title: Micro black hole

text: While Hawking radiation is sometimes questioned, Leonard Susskind summarizes an expert perspective in his book "The Black Hole War": "Every so often, a physics paper will appear claiming that black holes don't evaporate. Such papers quickly disappear into the infinite junk heap of fringe ideas."


title: Micro black hole

text: Conjectures for the final fate of the black hole include total evaporation and production of a Planck-mass-sized black hole remnant. Such Planck-mass black holes may in effect be stable objects if the quantized gaps between their allowed energy levels bar them from emitting Hawking particles or absorbing energy gravitationally like a classical black hole. In such case, they would be weakly interacting massive particles; this could explain dark matter.


title: Micro black hole

text: Production of a black hole requires concentration of mass or energy within the corresponding Schwarzschild radius. It was hypothesized by Zel'dovich and Novikov first and independently by Hawking that, shortly after the Big Bang, the Universe was dense enough for any given region of space to fit within its own Schwarzschild radius. Even so, at that time, the Universe was not able to collapse into a singularity due to its uniform mass distribution and rapid growth. This, however, does not fully exclude the possibility that black holes of various sizes may have emerged locally. A black hole formed in this way is called a primordial black hole and is the most widely accepted hypothesis for the possible creation of micro black holes. Computer simulations suggest that the probability of formation of a primordial black hole is inversely proportional to its mass. Thus, the most likely outcome would be micro black holes.


title: Micro black hole

text: A primordial black hole with an initial mass of around would be completing its evaporation today; a less massive primordial black hole would have already evaporated. Under optimal conditions, the Fermi Gamma-ray Space Telescope satellite, launched in June 2008, might detect experimental evidence for evaporation of nearby black holes by observing gamma ray bursts. It is unlikely that a collision between a microscopic black hole and an object such as a star or a planet would be noticeable. The small radius and high density of the black hole would allow it to pass straight through any object consisting of normal atoms, interacting with only few of its atoms while doing so. It has, however, been suggested that a small black hole of sufficient mass passing through the Earth would produce a detectable acoustic or seismic signal.


title: Micro black hole

text: In familiar three-dimensional gravity, the minimum energy of a microscopic black hole is (equivalent to 1.6 GJ or 444 kWh), which would have to be condensed into a region on the order of the Planck length. This is far beyond the limits of any current technology. It is estimated that to collide two particles to within a distance of a Planck length with currently achievable magnetic field strengths would require a ring accelerator about 1,000 light years in diameter to keep the particles on track.


title: Micro black hole

text: However, in some scenarios involving extra dimensions of space, the Planck mass can be as low as the TeV range. The Large Hadron Collider (LHC) has a design energy of for proton–proton collisions and 1,150 TeV for Pb–Pb collisions. It was argued in 2001 that, in these circumstances, black hole production could be an important and observable effect at the LHC or future higher-energy colliders. Such quantum black holes should decay emitting sprays of particles that could be seen by detectors at these facilities. A paper by Choptuik and Pretorius, published in 2010 in "Physical Review Letters", presented a computer-generated proof that micro black holes must form from two colliding particles with sufficient energy, which might be allowable at the energies of the LHC if additional dimensions are present other than the customary four (three spatial, one temporal).


title: Micro black hole

text: Hawking's calculation and more general quantum mechanical arguments predict that micro black holes evaporate almost instantaneously. Additional safety arguments beyond those based on Hawking radiation were given in the paper, which showed that in hypothetical scenarios with stable micro black holes massive enough to destroy Earth, such black holes would have been produced by cosmic rays and would have likely already destroyed astronomical objects such as planets, stars, or stellar remnants such as neutron stars and white dwarfs.


title: Micro black hole

text: It is possible, in some theories of quantum gravity, to calculate the quantum corrections to ordinary, classical black holes. Contrarily to conventional black holes, which are solutions of gravitational field equations of the general theory of relativity, quantum gravity black holes incorporate quantum gravity effects in the vicinity of the origin, where classically a curvature singularity occurs. According to the theory employed to model quantum gravity effects, there are different kinds of quantum gravity black holes, namely loop quantum black holes, non-commutative black holes, and asymptotically safe black holes. In these approaches, black holes are singularity-free.


title: Micro black hole

text: Virtual micro black holes were proposed by Stephen Hawking in 1995 and by Fabio Scardigli in 1999 as part of a Grand Unified Theory as a quantum gravity candidate.


title: Sundowning

text: Sundowning, or sundown syndrome, is a neurological phenomenon associated with increased confusion and restlessness in people with delirium or some form of dementia. It is most commonly associated with Alzheimer's disease but also found in those with other forms of dementia. The term "sundowning" was coined by nurse Lois K. Evans in 1987 due to the timing of the person's increased confusion beginning in the late afternoon and early evening. For people with sundown syndrome, a multitude of behavioral problems begin to occur and are associated with long term adverse outcomes. Sundowning seems to occur more frequently during the middle stages of Alzheimer's disease and mixed dementia and seems to subside with the progression of the person's dementia. People are generally able to understand that this behavioral pattern is abnormal. Research shows that 20–45% of people with Alzheimer's will experience some variation of sundowning confusion. However, despite lack of an official diagnosis of sundown syndrome in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), there is currently a wide range of reported prevalence.


title: Sundowning

text: The following social, economic, and physiological adverse outcomes are correlated with individuals affected by sundowning and their caregivers:


title: Sundowning

text: While the specific causes of sundowning have not been empirically proven, some evidence suggests that circadian rhythm disruption increases sundowning behaviors. In humans, sunset triggers a biochemical cascade that involves a reduction of dopamine levels and a shift towards melatonin production as the body prepares for sleep. In individuals with dementia, melatonin production may be decreased, which may interrupt other neurotransmitter systems.


title: Sundowning

text: Other causes or precipitating factors that may lead to sundown syndrome may include hormonal changes, disturbances in REM sleep, individual and/or caregiver fatigue, inappropriate medication use, or being predisposed to behavioral disorders from chronic neurological diseases. Resources in an institution's environment can also play a role as a symptom trigger. A reduced number of staff in the evening can attribute to more unmet needs and a lower threshold for agitation for individuals with sundown syndrome.


title: Sundowning

text: Sundowning should be distinguished from delirium, and could be presumed to be delirium when it appears as a new behavioral pattern until a causal link between sunset and behavioral disturbance is established. People with established sundowning and no obvious medical illness may be suffering from impaired circadian regulation, or may be affected by nocturnal aspects of their institutional environment such as shift changes, increased noise, or reduced staffing (which leads to fewer opportunities for social interaction). Delirium is generally an acute event that can span over a time period of hours to days.


title: Sundowning

text: It is thought that with the development of plaques and tangles associated with Alzheimer's disease there might be a disruption within the suprachiasmatic nucleus (SCN). The SCN is located in the hypothalamus and is associated with regulating sleep patterns by maintaining circadian rhythms, which are strongly associated with external light and dark cues. A disruption within the suprachiasmatic nucleus would seem to be an area that could cause the types of confusion that are seen in sundowning. However, finding evidence for this is difficult, as an autopsy is needed to analyze this disruption properly. By the time a person experiencing Alzheimer's has died, they have usually surpassed the level of brain damage (and associated dementia) that would be associated with sundowning. This hypothesis is, however, supported by the effectiveness of melatonin, a natural hormone, to decrease behavioral symptoms associated with sundowning. The pineal gland produces melatonin when signaled by the SCN to help maintain circadian rhythms. Melatonin supplementation can be administered to older adults as their natural hormonal production decreases over time.


title: Sundowning

text: Another cause can be oral problems, like tooth decay with pain. When the time a meal is served comes close, a person can show symptoms of sundowning. This cause is not widely recognized; however, anticipation of food can increase dopamine levels, and dopamine and melatonin have an antagonistic relationship.


title: Sundowning

text: Serotonin has also been observed to potentially have a key role in the regulation of circadian rhythm as research has shown that serotonergic agonism in the SCN results in "phase shifts" in portions of the light-dark cycle. In addition to the effects on circadian rhythm, serotonin is also known to be involved in the regulation of aggression. Due to the serotonergic signaling deficiencies of Alzheimer's disease, it has been commonly reported that deficiencies in serotonin have been associated with worsening circadian rhythm or aggression.


title: Sundowning

text: Elderly people often experience multiple comorbidities that may contribute to the phenomenon of sundowning syndrome through neurodegeneration.


title: Sundowning

text: Treatment of sundown syndrome may vary based upon when agitated behavior is observed throughout the day.


title: Sundowning

text: There are several pathways in the pipeline for scientists seeking therapeutic options for sundowning syndrome.


title: Sundowning

text: In addition to sundown syndrome not being officially recognized in the DSM-5, there is also the thought that sundown syndrome may be a phenomenon of caretakers' perception of patient agitation in the early afternoon to evening. Some studies have observed sundown syndrome occurring at times other than sunset which may suggest the symptoms associated with sundown syndrome are time-dependent rather than occurring specifically at sundown.


title: Cracker Jack

text: Cracker Jack is an American brand of snack food that consists of molasses-flavored, caramel-coated popcorn, and peanuts, well known for being packaged with a prize of trivial value inside. The Cracker Jack name and slogan, "The More You Eat The More You Want", were registered in 1896. Some food historians consider it the first junk food.