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Alpha (Ethology)
In studies of social animals, the highest ranking individual of a dominance hierarchy is sometimes designated as the alpha. Males, females, or both, can be alphas, depending on the species. Where one male and one female fulfill this role together, they are sometimes referred to as the alpha pair. Other animals in the same social group may exhibit deference or other species-specific subordinate behavior towards the alpha or alphas. Alpha animals usually gain preferential access to food and other desirable items or activities, though the extent of this varies widely between species. Male or female alphas may gain preferential access to sex or mates; in some species, only alphas or an alpha pair reproduce. Alphas may achieve their status by superior physical strength and aggression, or through social efforts and building alliances within the group, or more often, simply by breeding and being the parent of all in their pack. The individual with alpha status sometimes changes, often through a fight between the dominant and a subordinate animal. These fights are often to the death, depending on the animal.
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  • 04 Nov 2022
Topic Review
Varangian Guard
The Varangian Guard (Greek: Τάγμα τῶν Βαράγγων, Tágma tōn Varángōn) was an elite unit of the Byzantine Army, from the 10th to the 14th centuries, whose members served as personal bodyguards to the Byzantine Emperors. They are known for being primarily composed of Germanic peoples, specifically Norsemen from modern day Sweden (the Guard was formed approximately 200 years into the Viking Age) and Anglo-Saxons (after the Norman Conquest of England created an Anglo-Saxon diaspora, part of which found employment in Constantinople). The Rus' provided the earliest members of the Varangian Guard. They were in Byzantine service from as early as 874. The Guard was first formally constituted under Emperor Basil II in 988, following the Christianization of Kievan Rus' by Vladimir I of Kiev. Vladimir, who had recently usurped power in Kiev with an army of Varangian warriors, sent 6,000 men to Basil as part of a military assistance agreement. Basil's distrust of the native Byzantine guardsmen, whose loyalties often shifted, with fatal consequences, as well as the proven loyalty of the Varangians, many of whom had previously served in Byzantium, led the Emperor to employ them as his personal guardsmen. Immigrants from Sweden, Denmark , Norway and Iceland kept a predominantly Norse cast to the organization until the late 11th century. According to the late Swedish historian Alf Henrikson in his book Svensk Historia (History of Sweden), the Scandinavian Varangian guardsmen were recognized by long hair, a red ruby set in the left ear and ornamented dragons sewn on their chainmail shirts. In these years, Scandinavian men left to enlist in the Byzantine Varangian Guard in such numbers that a medieval Swedish law, Västergötlagen, from Västergötland declared no one could inherit while staying in "Greece"—the then Scandinavian term for the Byzantine Empire—to stop the emigration, especially as two other European courts simultaneously also recruited Scandinavians: Kievan Rus' c. 980–1060 and London 1018–1066 (the Þingalið). Composed primarily of Norsemen and Rus for the first 100 years, the Guard began to see increased numbers of Anglo-Saxons after the Norman conquest of England. By the time of the Emperor Alexios Komnenos in the late 11th century, the Varangian Guard was largely recruited from Anglo-Saxons and "others who had suffered at the hands of the Vikings and their cousins the Normans". The Anglo-Saxons and other Germanic peoples shared with the Vikings a tradition of faithful (to death if necessary) oath-bound service, and the Norman invasion of England resulted in many fighting men who had lost their lands and former masters and were looking for positions elsewhere. The Varangian Guard not only provided security for the Byzantine emperors, but also participated in many wars, often playing a decisive role, since they were usually deployed at critical moments of a battle. By the late 13th century, Varangians were mostly ethnically assimilated by the Byzantine Greeks, though the Guard remained in existence until at least mid-14th century. In 1400, there were still some people identifying themselves as "Varangians" in Constantinople.
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  • 04 Nov 2022
Topic Review
Cryptographic Engineering
Cryptographic Engineering is the discipline of using cryptography to solve human problems. Cryptography is typically applied when trying to ensure data confidentiality, to authenticate people or devices, or to verify data integrity in risky environments. Cryptographic engineering is a complicated, multidisciplinary field. It encompasses mathematics (algebra, finite groups, rings, and fields), computer engineering (hardware design, ASIC, embedded systems, FPGAs) and computer science (algorithms, complexity theory, software design). In order to practice state-of-the-art cryptographic design, mathematicians, computer scientists, and electrical engineers need to collaborate. Below are the main topics that are specifically related to cryptographic engineering: Cryptographic implementations Attacks against implementations and countermeasures against these attacks Tools and methodologies Applications Interactions between cryptographic theory and implementation issues
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  • 08 Nov 2022
Topic Review
Three Wise Monkeys
The three wise monkeys are a pictorial maxim, embodying the proverbial principle "see no evil, hear no evil, speak no evil". The three monkeys are Mizaru, covering his eyes, who sees no evil; Kikazaru, covering his ears, who hears no evil; and Iwazaru, covering his mouth, who speaks no evil. Lafcadio Hearn refers to them as the three mystic apes in his Glimpses of unfamiliar Japan (volume 2, page 127). There are various meanings ascribed to the monkeys and the proverb including associations with being of good mind, speech and action. In the Western world the phrase is often used to refer to those who deal with impropriety by turning a blind eye. Outside Japan the monkeys' names are sometimes given as Mizaru, Mikazaru, and Mazaru, as the last two names were corrupted from the Japanese originals. The monkeys are Japanese macaques, a common species in Japan.
  • 75.4K
  • 04 Nov 2022
Topic Review
Romansh Language
Romansh is a Romance language spoken in the Graubünden canton of eastern Switzerland, and is one of the official languages of the country. It is the native language of about 40,000 Swiss people and, of the major Romance languages, is most closely related to French. However, the accent and writing system of its speakers appear to the casual observer to more closely resemble Italian and German – a significant fact in historical conflicts over the region. Romansh is actually an umbrella term for several dialects, with each speech community in the region using different names for them. The term ‘Romansh’ is itself an anglicisation of the various local language names, including Romansch in German, and Rumantsch in Romansh itself. It is most closely related to Ladin and Friulian, varieties spoken in northern Italy, and together these form the Rhaeto-Romance sub-family of Gallo-Romance, a larger group that includes French and various varieties of northern Italy. These are only distantly related to standard Italian. 'Rhaeto-Romance' is sometimes considered a single language, and its three varieties dialects, and on occasions, 'Ladin' has been used to mean any or all of these.
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  • 04 Nov 2022
Topic Review
LCD Projector
An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector. To display images, LCD (liquid-crystal display) projectors typically send light from a metal-halide lamp through a prism or series of dichroic filters that separates light to three polysilicon panels – one each for the red, green and blue components of the video signal. As polarized light passes through the panels (combination of polarizer, LCD panel and analyzer), individual pixels can be opened to allow light to pass or closed to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image. Metal-halide lamps are used because they output an ideal color temperature and a broad spectrum of color. These lamps also have the ability to produce an extremely large amount of light within a small area; current projectors average about 2,000 to 15,000 American National Standards Institute (ANSI) lumens. Other technologies, such as Digital Light Processing (DLP) and liquid crystal on silicon (LCOS) are also becoming more popular in modestly priced video projection.
  • 4.3K
  • 04 Nov 2022
Topic Review
Proto-Northwest Caucasian
Proto-Northwest Caucasian (sometimes abbreviated PNWC), also Proto-Adyghe-Abazgi or Proto-Adyghe-Abkhaz, is the reconstructed common ancestor of the Northwest Caucasian languages.
  • 1.3K
  • 08 Nov 2022
Topic Review
A Beginner's Python Tutorial
Python is an interpreted programming language.
  • 1.6K
  • 04 Nov 2022
Topic Review
Date Rape Drug
A date rape drug is any drug that incapacitates another person and renders that person vulnerable to sexual assault, including rape. The substances are associated with date rape because of reported incidents of their use in the context of two people dating, during which the victim is sexually assaulted or raped or suffers other harm. The substances are not exclusively used to perpetrate sexual assault or rape, but are the properties or side-effects of substances normally used for legitimate medical purposes. One of the most common incapacitating agents for date rape is alcohol, administered either surreptitiously or consumed voluntarily, rendering the victim unable to make informed decisions or give consent.
  • 1.6K
  • 04 Nov 2022
Topic Review
Cray-2
The Cray-2 is a supercomputer with four vector processors made by Cray Research starting in 1985. At 1.9 GFLOPS peak performance, it was the fastest machine in the world when it was released, replacing the Cray X-MP in that spot. It was, in turn, replaced in that spot by the Cray Y-MP in 1988. The Cray-2 was the first of Seymour Cray's designs to successfully use multiple CPUs. This had been attempted in the CDC 8600 in the early 1970s, but the emitter-coupled logic (ECL) transistors of the era were too difficult to package into a working machine. The Cray-2 addressed this through the use of ECL integrated circuits, packing them in a novel 3D wiring that greatly increased circuit density. The dense packaging and resulting heat loads were a major problem for the Cray-2. This was solved in a unique fashion by forcing the electrically inert Fluorinert liquid through the circuitry under pressure and then cooling it outside the processor box. The unique "waterfall" cooler system came to represent high-performance computing in the public eye and was found in many informational films and as a movie prop for some time. Unlike the original Cray-1, the Cray-2 had difficulties delivering peak performance. Other machines from the company, like the X-MP and Y-MP, outsold the Cray-2 by a wide margin. When Cray began development of the Cray-3, the company chose to develop the Cray C90 series instead. This is the same sequence of events that occurred when the 8600 was being developed, and as in that case, Cray left the company.
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  • 04 Nov 2022
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