A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind-pollinated (anemophilous) but sometimes insect-pollinated (as in Salix). They contain many, usually unisexual flowers, arranged closely along a central stem that is often drooping. They are found in many plant families, including Betulaceae, Fagaceae, Moraceae, and Salicaceae. Occurrence Catkin-bearing plants include many trees or shrubs such as birch, willow, aspen, hickory, sweet chestnut, and sweetfern (Comptonia). In many of these plants, only the male flowers form catkins, and the female flowers are single (hazel, oak), a cone (alder), or other types (mulberry). In other plants (such as poplar), both male and female flowers are borne in catkins. In Britain, they can be seen in January or February, when many trees are bare for winter. They can even occur in December. Evolution For some time, catkins were believed to be a key synapomorphy among the proposed Hamamelididae, also known as Amentiferae (i.e., literally plants bearing aments...

The almond (Prunus amygdalus, syn. Prunus dulcis) is a species of tree native to Iran and surrounding countries, including the Levant. The almond is also the name of the edible and widely cultivated seed of this tree. Within the genus Prunus, it is classified with the peach in the subgenus Amygdalus, distinguished from the other subgenera by corrugations on the shell (endocarp) surrounding the seed.The fruit of the almond is a drupe, consisting of an outer hull and a hard shell with the seed, which is not a true nut. Shelling almonds refers to removing the shell to reveal the seed. Almonds are sold shelled or unshelled. Blanched almonds are shelled almonds that have been treated with hot water to soften the seedcoat, which is then removed to reveal the white embryo. Once almonds are cleaned and processed, they can be stored over time. Almonds are used in many food cuisines, often featuring prominently in desserts, such as marzipan. The almond tree prospers in a moderate Mediterranean climate with cool winter weather. California produces over half of the world's almond supply. Due...

An intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence. The abbreviation "IQ" was coined by the psychologist William Stern for the German term Intelligenzquotient, his term for a scoring method for intelligence tests at University of Breslau he advocated in a 1912 book.Historically, IQ was a score obtained by dividing a person's mental age score, obtained by administering an intelligence test, by the person's chronological age, both expressed in terms of years and months. The resulting fraction (quotient) was multiplied by 100 to obtain the IQ score. For modern IQ tests, the raw score is transformed to a normal distribution with mean 100 and standard deviation 15. This results in approximately two-thirds of the population scoring between IQ 85 and IQ 115 and about 2.5 percent each above 130 and below 70.Scores from intelligence tests are estimates of intelligence. Unlike, for example, distance and mass, a concrete measure of intelligence cannot be achieved given the abstract nature of the concept of "intelligence". IQ scores have been...

The Greco-Persian Wars (also often called the Persian Wars) were a series of conflicts between the Achaemenid Empire and Greek city-states that started in 499 BC and lasted until 449 BC. The collision between the fractious political world of the Greeks and the enormous empire of the Persians began when Cyrus the Great conquered the Greek-inhabited region of Ionia in 547 BC. Struggling to control the independent-minded cities of Ionia, the Persians appointed tyrants to rule each of them. This would prove to be the source of much trouble for the Greeks and Persians alike. In 499 BC, the tyrant of Miletus, Aristagoras, embarked on an expedition to conquer the island of Naxos, with Persian support; however, the expedition was a debacle and, preempting his dismissal, Aristagoras incited all of Hellenic Asia Minor into rebellion against the Persians. This was the beginning of the Ionian Revolt, which would last until 493 BC, progressively drawing more regions of Asia Minor into the conflict. Aristagoras secured military support from Athens and Eretria, and in 498 BC these forces helped to capture and burn the Persian regional capital...

Writing is a neuropsychological activity involving cognitive and physical processes and the use of writing systems to structure and translate human thoughts into persistent representations of human language. A system of writing relies on many of the same semantic structures as the language it represents, such as lexicon and syntax, with the added dependency of a system of symbols representing that language's phonology and morphology. Nevertheless, written language may take on characteristics distinctive from any available in spoken language.The outcome of this activity, also called "writing," and sometimes a "text," is a series of physically inscribed, mechanically transferred, or digitally represented linguistic symbols. The interpreter or activator of a text is called a "reader".Writing systems do not themselves constitute languages (with the debatable exception of computer languages); they are a means of rendering language into a form that can be reconstructed by other humans separated by time and/or space. While not all languages use a writing system, those that do can complement and extend capacities of spoken language by...

Music hall is a type of British theatrical entertainment that was popular from the early Victorian era, beginning around 1850. It faded away after 1918 as the halls rebranded their entertainment as variety. Perceptions of a distinction in Britain between bold and scandalous Music Hall and subsequent, more respectable Variety differ. Music hall involved a mixture of popular songs, comedy, speciality acts, and variety entertainment. The term is derived from a type of theatre or venue in which such entertainment took place. In North America vaudeville was in some ways analogous to British music hall, featuring rousing songs and comic acts. Originating in saloon bars within public houses during the 1830s, music hall entertainment became increasingly popular with audiences. So much so, that during the 1850s some public houses were demolished, and specialised music hall theatres developed in their place. These theatres were designed chiefly so that people could consume food and alcohol and smoke tobacco in the auditorium while the entertainment took place, with the cheapest seats located in the gallery. This differed from the...

An intervertebral disc (or intervertebral fibrocartilage) lies between adjacent vertebrae in the vertebral column. Each disc forms a fibrocartilaginous joint (a symphysis), to allow slight movement of the vertebrae, to act as a ligament to hold the vertebrae together, and to function as a shock absorber for the spine. Structure Intervertebral discs consist of an outer fibrous ring, the anulus fibrosus disci intervertebralis, which surrounds an inner gel-like center, the nucleus pulposus. The anulus fibrosus consists of several layers (laminae) of fibrocartilage made up of both type I and type II collagen. Type I is concentrated toward the edge of the ring, where it provides greater strength. The stiff laminae can withstand compressive forces. The fibrous intervertebral disc contains the nucleus pulposus and this helps to distribute pressure evenly across the disc. This prevents the development of stress concentrations which could cause damage to the underlying vertebrae or to their endplates. The nucleus pulposus contains loose fibers suspended in a mucoprotein gel. The nucleus of the disc acts...

The mineral olivine () is a magnesium iron silicate with the chemical formula (Mg,Fe)2SiO4. It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickly on the surface. For this reason, olivine has been proposed as a good candidate for accelerated weathering to sequester carbon dioxide from the Earth's oceans and atmosphere, as part of climate change mitigation. Olivine also has many other historical uses, such as the gemstone peridot (or chrysolite), as well as industrial applications like metalworking processes. The ratio of magnesium to iron varies between the two endmembers of the solid solution series: forsterite (Mg-endmember: Mg2SiO...

Punxsutawney (; Lenape: Punkwsutènay) is a borough in southern Jefferson County, Pennsylvania, United States. Punxsutawney is known globally for its annual Groundhog Day celebration held each February 2, during which thousands of attendees and international media outlets visit the town for an annual weather prediction by the groundhog Punxsutawney Phil, though the actual prediction location, Gobbler's Knob, is actually in adjacent Young Township.The borough, located 84 miles (135 km) northeast of Pittsburgh and 50 miles (80 km) northwest of Altoona, was incorporated in 1850. With a population of 5,962 as of the 2010 census, Punxsutawney is the largest incorporated municipality in Jefferson County. History Shawnee wigwam villages once occupied this site on the Mahoning Creek. The first settlement that included non-indigenous people was in 1772, when Reverend John Ettwein, a Moravian Church missionary, arrived with a band of 241 Christianized Delaware Indians. Swarms of gnats plagued early settlers and their livestock for years, and are blamed for...

The Republic of Korea Army (ROKA; Korean: 대한민국 육군; Hanja: 大韓民國陸軍; RR: Daehanminguk Yukgun), also known as the ROK Army or South Korean Army, is the army of South Korea, responsible for ground-based warfare. It is the largest of the military branches of the Republic of Korea Armed Forces with 420,000 members as of 2020. This size is maintained through conscription; South Korean men must complete military service (18 months for army, auxiliary police and marine, 20 months for navy and conscripted firefighter, 21 months for air force and social service, 36 months for alternative service) between the age of 18 and 35. History The modern South Korean army traces its lineage back to the Gwangmu Reform, when the Byeolgigun was established by Emperor Gojong in 1881. The 1st of every October is celebrated in South Korea as Armed Forces Day. It commemorates the day during the Korean War when units of...