Monday, March 31, 2014
Radiosurgery is a medical procedure that allows non-invasive treatment of benign and malignant tumors. It is also known as stereotactic radiotherapy, (SRT) when used to target lesions in the brain, and stereotactic body radiotherapy (SBRT) when used to target lesions in the body. In addition to cancer, it has also been shown to be beneficial for the treatment of some non-cancerous conditions, including functional disorders such as arteriovenous malformations (AVMs) and trigeminal neuralgia.
Sunday, March 30, 2014
Saturday, March 29, 2014
Wunderwaffe is German for "wonder-weapon" and was a term assigned during World War II by the German propaganda ministry to a few revolutionary "superweapons". Most of these weapons however remained more or less feasible prototypes, or reached the combat theatre too late, and in too insignificant numbers (if at all) to have a military effect. A derisive abbreviation of the term emerged: Wuwa, pronounced "voo-vah".
The V-weapons, which were developed earlier and saw considerable deployment (especially against London and Antwerp), trace back to the same pool of highly inventive armament concepts. Therefore, they are also included here.
Although the Wunderwaffen failed to meet their strategic objective of turning the tides of World War II in Nazi Germany's favor at a time when the war was already strategically lost, they represented designs and prototypes that were extremely advanced for their time.
Friday, March 28, 2014
Hebbian theory describes a basic mechanism for synaptic plasticity wherein an increase in synaptic efficacy arises from the presynaptic cell's repeated and persistent stimulation of the postsynaptic cell. Introduced by Donald Hebb in 1949, it is also called Hebb's rule, Hebb's postulate, and cell assembly theory, and states:
- Let us assume that the persistence or repetition of a reverberatory activity (or "trace") tends to induce lasting cellular changes that add to its stability.… When an axon of cell A is near enough to excite a cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased.
The theory is often summarized as "Cells that fire together, wire together." It attempts to explain "associative learning", in which simultaneous activation of cells leads to pronounced increases in synaptic strength between those cells. Such learning is known as Hebbian learning.
Thursday, March 27, 2014
They are also sometimes thought of as a neural network or fragment of memory, sometimes using a hologram analogy to describe its action in light of results showing that memory appears not to be localized in the brain. The existence of engrams is posited by some scientific theories to explain the persistence of memory and how memories are stored in the brain. The existence of neurologically defined engrams is not significantly disputed, though their exact mechanism and location has been a focus of persistent research for many decades.
In the fields of computational linguistics and probability, an n-gram is a contiguous sequence of n items from a given sequence of text or speech. The items in question can be phonemes, syllables, letters, words or base pairs according to the application. n-grams are collected from a text or speech corpus.
An n-gram of size 1 is referred to as a "unigram"; size 2 is a "bigram" (or, less commonly, a "digram"); size 3 is a "trigram". Larger sizes are sometimes referred to by the value of n, e.g., "four-gram", "five-gram", and so on.
Wednesday, March 26, 2014
Country wine can refer to
Tuesday, March 25, 2014
Monday, March 24, 2014
Respondeat superior (Latin: "let the master answer"; plural: respondeant superiores) is a legal doctrine which states that, in many circumstances, an employer is responsible for the actions of employees performed within the course of their employment. This rule is also called the "Master-Servant Rule", recognized in both common law and civil law jurisdictions.
In a broader scope, respondeat superior is based upon the concept of vicarious liability.
Sunday, March 23, 2014
Neologism, no etymology, but constructed from Greek gune, -aikos (γυνή, -αικος) 'woman' and kratia (κρατία) 'power'. Disambiguates usage of matriarchy: gynecocracy refers to societies ruled by women, distinct from matrilineal bequeathing of property and matrilocal residence of brides.
Saturday, March 22, 2014
On the 8th of September 1930, the mathematician David Hilbert pronounced his disagreement in a celebrated address to the Society of German Scientists and Physicians, in Königsberg:
- We must not believe those, who today, with philosophical bearing and deliberative tone, prophesy the fall of culture and accept the ignorabimus. For us there is no ignorabimus, and in my opinion none whatever in natural science. In opposition to the foolish ignorabimus our slogan shall be: Wir müssen wissen — wir werden wissen! ('We must know — we will know!')
Friday, March 21, 2014
Founded by Tela Tella in the 1970s, the sect predominantly exists in Lagos, Nigeria. Its followers recognise both the Bible and the Qur'an as holy texts, and practice "running deliverance," a distinctive practice of spiritual running which members liken to Joshua's army that took Jericho, or the Muslim practice of walking around the Ka'aba.
The religion has about 1,500 adherents.
Thursday, March 20, 2014
Wednesday, March 19, 2014
Tuesday, March 18, 2014
Monday, March 17, 2014
Après-ski (French: after skiing) refers to going out, having drinks, dancing, and generally socializing after skiing. It is popular in the Alps, where skiers often stop at bars on their last run of the day while still wearing all their ski gear. The concept is similar to the nineteenth hole in golf. This can also happen anywhere in the world where there is snow. In the United States, the term is used more broadly to describe the atmosphere of ski resorts and ski culture, ski themed architecture and decor, and the ski oriented lifestyle in general.
Austria is considered to be the country of provenance, for example, the Austrian ski resorts St. Anton, Ischgl, Sölden, Saalbach-Hinterglemm and the Zillertal. In the Netherlands, après-ski huts are found in many clubs and bars. In these huts, après-ski music is played, which is mostly covers or parodies of old songs. These huts are aimed primarily at young adults and teenagers.
The term après-ski is also being increasingly applied in a derogatory sense, to describe those whose interest in snow sports is mainly confined to image, such as expensive prestige brands of equipment and seasonal ski-wear fashion.
Sunday, March 16, 2014
Scandium is a chemical element with symbol Sc and atomic number 21. A silvery-white metallic transition metal, it has historically been sometimes classified as a rare earth element, together with yttrium and the lanthanoids. It was discovered in 1879 by spectral analysis, of the minerals euxenite and gadolinite from Scandinavia.
Scandium is present in most of the deposits of rare earth and uranium compounds, but it is extracted from these ores in only a few mines worldwide. Because of the low availability and the difficulties in the preparation of metallic scandium, which was first done in 1937, it took until the 1970s before applications for scandium were developed. The positive effects of scandium on aluminium alloys were discovered in the 1970s, and its use in such alloys remains its only major application.
The properties of scandium compounds are intermediate between those of aluminium and yttrium. A diagonal relationship exists between the behavior of magnesium and scandium, just as there is between beryllium and aluminium. In the chemical compounds of the elements shown as group 3, above, the predominant oxidation state is +3.
Saturday, March 15, 2014
Friday, March 14, 2014
Thursday, March 13, 2014
Fractography is the study of fracture surfaces of materials. Fractographic methods are routinely used to determine the cause of failure in engineering structures, especially in product failure and the practice of forensic engineering or failure analysis. In material science research, fractography is used to develop and evaluate theoretical models of crack growth behavior.
One of the aims of fractographic examination is to determine the cause of failure by studying the characteristics of a fracture surface. Different types of crack growth (e.g. fatigue, stress corrosion cracking, hydrogen embrittlement) produce characteristic features on the surface, which can be used to help identify the failure mode. The overall pattern of cracking can be more important than a single crack, however, especially in the case of brittle materials like ceramics and glasses.
Wednesday, March 12, 2014
Tuesday, March 11, 2014
Monday, March 10, 2014
Nikāḥ al-Mutʿah (Arabic: نكاح المتعة "pleasure marriage"), is a fixed-term marriage in Shi'a Islam. The duration of this type of marriage is fixed at its inception and is then automatically dissolved upon completion of its term. The marriage is contractual and is subject to renewal. Financial payments may be made between the couple, usually with the male paying the female known as mahr or dower.
Sunday, March 9, 2014
Forseti (Old Norse "the presiding one," actually "president" in Modern Icelandic and Faroese) is an Æsir god of justice and reconciliation in Norse mythology. He is generally identified with Fosite, a god of the Frisians. Jacob Grimm noted that if, as Adam of Bremen states, Fosite's sacred island was Heligoland, that would make him an ideal candidate for a deity known to both Frisians and Scandinavians, but that it is surprising he is never mentioned by Saxo Grammaticus.Grimm took Forseti, "praeses", to be the older form of the name, first postulating an unattested Old High German equivalent *forasizo (cf. modern German Vorsitzender "one who presides"). but later preferring a derivation from fors, a 'whirling stream' or 'cataract', connected to the spring and the god's veneration by seagoing peoples. However, in other Old Norse words, for example forboð, 'forbidding, ban', the prefix for- has a pejorative sense. So it is more plausible that Fosite is the older name and Forseti a folk etymology.
Saturday, March 8, 2014
Kafes, literally "the cage", was the part of the Imperial Harem of the Ottoman Palace where possible successors to the throne were kept under a form of house-arrest and constant surveillance by the palace guards.
The early history of the Ottoman Empire is littered with succession wars between rival sons of the deceased sultan. It was common for a new sultan to have his brothers killed, including infants, sometimes dozens of them at once. This practice reduced the number of claimants to the throne, leading to several occasions where the Ottoman line seemed destined to end. The confinement of heirs provided security for an incumbent sultan and continuity of the dynasty.
Friday, March 7, 2014
The term was coined in 1958 by Klaus Conrad, who defined it as the "unmotivated seeing of connections" accompanied by a "specific experience of an abnormal meaningfulness", but it has come to represent the human tendency to seek patterns in random nature in general, as with gambling, paranormal phenomena, religion, and even attempts at scientific observation.
Thursday, March 6, 2014
The autobus forms on mountain stages when non-climbers fall off the back of peloton during the climb. Gradually some riders fall off the back of the peloton and form a large group at the end of the race. These riders are generally sprinters or domestiques unconcerned about their finishing positions in the mountain stages. Their primary concern is beating the elimination time to ensure their survival in a multi-stage race such as the Tour de France.
Wednesday, March 5, 2014
A commissaire is an official in competitive cycling, usually seen with a copy of the racing rules, a stopwatch and a clipboard. Commissaires are similar to judges or referees in other sports — a commissaire is the person in charge of the race and the Chief Commissaire has the power to shut down the event if protocols are breached.
Their main aim is to ensure the racing is both fair and safe. The Commissaire is independent and impartial. They ensure safety of the track and check for appropriate safety gear. Fairness is ensured by checking equipment and policing any disputes.
Tuesday, March 4, 2014
Monday, March 3, 2014
Histology (compound of the Greek words: ἱστός "tissue", and -λογία -logia) is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope. Histological studies may be conducted via tissue culture, where live cells can be isolated and maintained in a proper environment outside the body for various research projects. The ability to visualize or differentially identify microscopic structures is frequently enhanced through the use of histological stains. Histology is an essential tool of biology and medicine.
Histopathology, the microscopic study of diseased tissue, is an important tool in anatomical pathology, since accurate diagnosis of cancer and other diseases usually requires histopathological examination of samples. Trained medical doctors, frequently board-certified as pathologists, are the personnel who perform histopathological examination and provide diagnostic information based on their observations.
The trained scientists who perform the preparation of histological sections are histotechnicians, histology technicians (HT), histology technologists (HTL), medical scientists, medical laboratory technicians, or biomedical scientists. Their field of study is called histotechnology.