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Cell (biology)

The cell is the basic structural and biological unit of all known organisms. A cell is the smallest unit of life. Cells are called the "building blocks of life"; the study of cells is called cellular biology, or cytology. Cells consist of cytoplasm enclosed within a membrane, which contains many biomolecules such as proteins and nucleic acids. Most plant and animal cells are only visible under a microscope, with dimensions between 1 and 100 micrometres. Organisms can be classified as multicellular. Most unicellular organisms are classed as microorganisms; the number of cells in plants and animals varies from species to species, it has been estimated that humans contain somewhere around 40 trillion cells. The human brain accounts for around 80 billion of these cells. Cells were discovered by Robert Hooke in 1665, who named them for their resemblance to cells inhabited by Christian monks in a monastery. Cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that cells are the fundamental unit of structure and function in all living organisms, that all cells come from pre-existing cells.

Cells emerged on Earth at least 3.5 billion years ago. Cells are of two types: eukaryotic, which contain a nucleus, prokaryotic, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular. Prokaryotes include two of the three domains of life. Prokaryotic cells were the first form of life on Earth, characterized by having vital biological processes including cell signaling, they are simpler and smaller than eukaryotic cells, lack a nucleus, other membrane-bound organelles. The DNA of a prokaryotic cell consists of a single circular chromosome, in direct contact with the cytoplasm; the nuclear region in the cytoplasm is called the nucleoid. Most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter. A prokaryotic cell has three regions: Enclosing the cell is the cell envelope – consisting of a plasma membrane covered by a cell wall which, for some bacteria, may be further covered by a third layer called a capsule.

Though most prokaryotes have both a cell membrane and a cell wall, there are exceptions such as Mycoplasma and Thermoplasma which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, serving as a protective filter; the cell wall consists of peptidoglycan in bacteria, acts as an additional barrier against exterior forces. It prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment; some eukaryotic cells have a cell wall. Inside the cell is the cytoplasmic region that contains the genome and various sorts of inclusions; the genetic material is found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are circular. Linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid.

Plasmids encode additional genes, such as antibiotic resistance genes. On the outside and pili project from the cell's surface; these are structures made of proteins that facilitate communication between cells. Plants, fungi, slime moulds and algae are all eukaryotic; these cells are about fifteen times wider than a typical prokaryote and can be as much as a thousand times greater in volume. The main distinguishing feature of eukaryotes as compared to prokaryotes is compartmentalization: the presence of membrane-bound organelles in which specific activities take place. Most important among these is a cell nucleus, an organelle that houses the cell's DNA; this nucleus gives the eukaryote its name, which means "true kernel". Other differences include: The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell walls may not be present; the eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins.

All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles such as mitochondria contain some DNA. Many eukaryotic cells are ciliated with primary cilia. Primary cilia play important roles in chemosensation and thermosensation; each cilium may thus be "viewed as a sensory cellular antennae that coordinates a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation." Motile eukaryotes can move using motile flagella. Motile cells are absent in flowering plants. Eukaryotic flagella are more complex than those of prokaryotes. All cells, whether prokaryotic or eukaryotic, have a membrane that envelops the cell, regulates what moves in and out, maintains the electric potential of the cell. Inside the membrane, the cytoplasm takes up most of the cell's volume. All cells possess DNA, the hereditary material of genes, RNA, containing the information necessary to build various proteins such as enzymes, the cell's primary machi

Flight to Varennes

The royal Flight to Varennes during the night of 20–21 June 1791 was a significant episode in the French Revolution in which King Louis XVI of France, his queen Marie Antoinette, their immediate family unsuccessfully attempted to escape from Paris in order to initiate a counter-revolution at the head of loyal troops under royalist officers concentrated at Montmédy near the frontier. They escaped only as far as the small town of Varennes, where they were arrested after having been recognized at their previous stop in Sainte-Menehould; this incident was a turning point after which popular hostility towards the French monarchy as an institution, as well as towards the king and queen as individuals, became much more pronounced. The king's attempted flight provoked charges of treason that led to his execution in 1793; the escape failed due to a series of misadventures, misinterpretations, poor judgments. Much was due to the king's indecision. Furthermore, he overestimated popular support for the traditional monarchy, mistakenly believing only Parisian radicals supported the revolution and that the populace as a whole opposed it.

Most fatally, he felt he enjoyed the favor of the peasantry and other commoners, the people who foiled his plan and detained him. The king's flight was traumatic for France, inciting reactions ranging from anxiety to violence and panic. Everyone was aware; the realization that the king had effectually repudiated the revolutionary reforms made up to that point came as a shock to people who had seen him as a well-intentioned monarch who governed as a manifestation of God's will. Republicanism evolved from being a subject of coffeehouse debate to the dominant ideal of revolutionary leaders. Louis XVI's indecisive response was one of the causes of the forcible transfer of the royal family from the Palace of Versailles to the Tuileries in Paris on 6 October 1789 after The Women's March on Versailles; the relocation seemed to have paralyzed the king, which left many important decisions to the politically untrained queen. On 28 February 1791, while the Marquis de Lafayette was handling a conflict in Vincennes, hundreds of royalists came to the Tuileries to demonstrate in support of the royal family, only to be expelled from the palace by National Guards.

The intended goal of the unsuccessful flight was to provide the king with greater freedom of action and personal security than was possible in Paris. At Montmédy General François Claude de Bouillé, the marquis de Bouillé, had concentrated a force of 10,000 regulars of the old royal army who were considered to still be loyal to the monarchy. De Bouillé himself had shown energy in suppressing a serious mutiny in Nancy in 1790; the troops under his command included two Swiss and four German mercenary regiments who were perceived as being more reliable in a time of general political unrest than their French counterparts. In a letter drafted for presentation to the Diet of the Swiss Cantons at Zurich, the royalist baron de Breteuil stated that "His Majesty desires to have such imposing forces at his disposition, that the most audacious rebels will have no other option than to submit"; the court expectation was that "numerous faithful subjects of all classes" would rally to demand the restoration of the rights of the throne and that order would be restored without the need for civil war or foreign invasion.

The long-term political objectives of the royal couple and their closest advisors remain unclear. A detailed document entitled Declaration to the French People prepared by Louis for presentation to the National Assembly and left behind in the Tuileries indicates that his personal goal was a return to the concessions and compromises contained in the declaration of the Third Estate on 23 June 1789 prior to the outbreak of violence in Paris and the storming of the Bastille. Private correspondence from Marie Antoinette takes a more reactionary line looking to a restoration of the old monarchy without concessions. Prodded by the queen, Louis committed himself and his family to a disastrous attempt of escape from the capital to the eastern frontier on 21 June 1791. With the dauphin's governess, the Marquise de Tourzel, taking on the role of a Russian baroness, the queen and the king's sister Madame Élisabeth playing the roles of governess and nurse the king a valet, the royal children her daughters, the royal family made their escape leaving the Tuileries Palace at about midnight.

The escape was planned by the queen's favourite, the Swedish Count Axel von Fersen and the Baron de Breteuil, who had garnered support from Swedish King Gustavus III. Fersen had urged the use of two light carriages that could have made the 200-mile journey to Montmédy quickly; this would have involved the splitting up of the royal family, thus Louis and Marie-Antoinette decided on the use of a heavy and conspicuous coach drawn by six horses. Due to the cumulative effect of slow progression, time miscalculations, lack of secrecy, the need to repair broken coach traces, the royal family was thwarted in its escape attempt after leaving Paris. Louis himself chatted with peasants while horses were being changed at Fromentieres and Marie Antoinette gave silver dishes to a helpful local official at Chaintrix. At Châlons townspeople greeted and applauded the royal party. Jean-Baptiste Drouet, the postmaster of Sainte-Menehould, recognized the king from his portrait printed on an assignat in his possession.

Seven detachments of c

Drum Tower and Bell Tower of Beijing

The Drum Tower of Beijing, or Gulou, is situated at the northern end of the central axis of the Inner City to the north of Di'anmen Street. Built for musical reasons, it was used to announce the time and is now a tourist attraction; the Bell Tower of Beijing, or Zhonglou, stands behind the drum tower. Together, the Bell Tower and Drum Tower have panoramic views over central Beijing and before the modern era, they both dominated Beijing's ancient skyline. Bells and drums were musical instruments in ancient China, they were used by government and communities to announce the time. The Bell and Drum towers were central to official timekeeping in China in the Yuan and Qing dynasties; the Bell and Drum Towers continued to function as the official timepiece of Beijing until 1924, when the Beijing Coup led to the expulsion of Puyi, the last emperor of the Qing Dynasty, from the Forbidden City, the adoption of western-styled clockwork for official time-keeping. The Drum Tower was built in 1272 during the reign of Kublai Khan, at which time it stood at the heart of the Yuan capital Dadu.

At that time it was known as the Tower of Orderly Administration. In 1420, under the Yongle Emperor of the Ming dynasty, the building was reconstructed to the east of the original site and in 1800 under the Jiaqing Emperor of the Qing dynasty, large-scale renovations were carried out. Following the Beijing Coup in 1924, Feng Yuxiang removed the official status of the towers, replacing them with western time-keeping methods, renamed the building "Mingchilou", or the "tower of clarifying shame". Objects related to the Eight-Nation Alliance's invasion of Beijing and the May 30 Massacre of 1925 were put on display, turning the towers into a museum; the upper story of the building serves as the People's Cultural Hall of the East City District. In the 1980s, after much repair, the Bell and Drum Towers were opened to tourists; the Drum Tower is a two-story building made of wood with a height of 47 metres. In the upper story of the building housed 24 drums, of which only one survives. New drums had been build to replace them.

Nearby stands the Bell Tower, a 33-metre-high edifice with gray walls and a green glazed roof. Imperial City, Beijing 2008 Beijing Drum Tower stabbings Chinaguide.com: The Beijing Drum Tower — 360-degree virtual tour and photographs. Kinabaloo.com: The Drum and Bell Towers in Beijing — 30 high quality photographs

Above the Earth, Below the Sky

Above the Earth, Below the Sky is the first full-length studio album by American post-rock band If These Trees Could Talk. It was independently released on March 11, 2009 and re-released by The Mylene Sheath on vinyl the following year released once again through Metal Blade in January 2015; the album was recorded and mastered by Tim Gerak at Mammoth Cave Studio in Akron. The album was produced by Tim Gerak. Nathaniel Lay of New Noise Magazine gave the album a positive review describing the album as an "ambitious beginning" noting a "" in their "heavier movements", he summarized stating "You don't have to be a lover of instrumental to get lost within." All songs written by. If These Trees Could TalkTom Fihe – bass Zack Kelly – drums Cody Kelly – guitar Jeff Kalal – guitar Mike Socrates – guitarProductionTim Gerak – engineering, mastering, producer Zack Kelly – producer

Green Hill, Tennessee

Green Hill is a census-designated place in western Wilson County, Tennessee. The population was 6,618 at the 2010 census. Green Hill was first settled before 1800 by John Cloyd and John Williamson, who moved their families to the area from Nashville to escape a smallpox outbreak. Colonel John Donelson, Jr. established a summer home at Green Hill. The community's name may be a description of the location or may honor a former state treasurer of North Carolina. During the 19th century, Green Hill was the site of a post office, established in 1834 or 1838 and closed in 1904. Shortly before the outbreak of the Civil War, Green Hill supported a high school. Businesses included a general store, a hotel, a tobacco processor, a flour mill, a carding machine. A new high school is set to open at the junction of Lebanon Road and North Greenhill Road in August 2020. Green Hill is located at 36°13′51″N 86°34′25″W. According to the United States Census Bureau, the CDP has a total area of 4.4 square miles, of which 3.9 square miles is land and 0.5 square miles is water.

As of the census of 2000, there were 7,068 people, 2,555 households, 2,141 families residing in the CDP. The population density was 1,815.7 people per square mile. There were 2,613 housing units at an average density of 671.3/sq mi. The racial makeup of the CDP was 94.57% White, 3.03% African American, 0.16% Native American, 0.72% Asian, 0.03% Pacific Islander, 0.31% from other races, 1.19% from two or more races. Hispanic or Latino of any race were 0.96% of the population. There were 2,555 households out of which 37.3% had children under the age of 18 living with them, 72.6% were married couples living together, 8.5% had a female householder with no husband present, 16.2% were non-families. 13.0% of all households were made up of individuals and 3.4% had someone living alone, 65 years of age or older. The average household size was 2.77 and the average family size was 3.02. In the CDP, the population was spread out with 25.6% under the age of 18, 6.7% from 18 to 24, 28.3% from 25 to 44, 31.4% from 45 to 64, 8.0% who were 65 years of age or older.

The median age was 40 years. For every 100 females, there were 100.1 males. For every 100 females age 18 and over, there were 96.5 males. The median income for a household in the CDP was $62,690, the median income for a family was $66,610. Males had a median income of $45,931 versus $31,237 for females; the per capita income for the CDP was $25,926. About 2.4% of families and 3.4% of the population were below the poverty line, including 6.1% of those under age 18 and 0.9% of those age 65 or over. Drake Macon, Alice Chastain, & Hershell Ligon. 1946. The history of Green Hill. N.p. 1946. 20 pp

Harry W. Bass Jr.

Harry W. Bass Jr. was an American businessman, coin collector, philanthropist. He was active in the Texas Republican Party during the late 1950s when the state was still dominated by the Democratic Party. In 1970, Bass and his brother Richard inherited the Goliad Gas Corporation. Bass invested in ski resorts in Vail, Colorado, he was the main developer of the Beaver Creek Resort in Beaver Creek. He amassed one of the world's great coin collections and served as the president of the American Numismatic Society. Bass was born in Oklahoma, his father, Harry W. Bass Sr. was a co-founder of the Goliad Corporation and the Goliad Oil and Gas Corporation in Duncanville, near Dallas, Texas. He had Richard Bass. Bass was educated at the St. Mark's School of Texas known as the Texas Country Day School, he attended Southern Methodist University. During World War II, he served in the South Pacific with the United States Navy. Bass started his career in Calgary, Canada for his father's oil and gas companies. Bass launched a voter data-collection company and served as the finance chairman of the Republican Party of Dallas County in the late 1950s.

The company proved to be a financial failure. He was elected chairman of the Dallas County GOP in 1957, but resigned that year. By 1960, alongside Republican U. S. Representative Bruce Alger of Texas' 5th congressional district, he staged a demonstration against Democratic U. S. Senator Lyndon B. Johnson when the latter visited Dallas, he was a delegate to the 1964 Republican National Convention. Bass co-owned a private company headquartered in Dallas, he invested in the development of ski resorts in Aspen, Colorado, in 1955. He owned 7 percent of the Aspen Ski Corporation with his brother, he invested in the development of Vail and became majority shareholder of Vail Associates, Inc. with 57 percent in 1978. He served as its chairman by 1979, he expanded his holdings to include Beaver Creek Resort. Bass began collecting coins in the middle 1960s, he attended coin auctions. By 1976, he had invested "millions of dollars" in coins, he added that he had 25 per cent of my portfolio in coins," of which were gold coins from the 19th century to 1933.

They were held in a trust. He became a member of the American Numismatic Society in 1966. By 1979, he was its president. Bass founded the Harry W. Bass Jr. Research Foundation in 1991. One of its goals was to support numismatics. Bass married Mary Mathewson in 1947, he married Doris Wampler Calhoun. Bass died on April 4, 1998 in Dallas and is interred at the Sparkman-Hillcrest Memorial Park Cemetery. Shortly after his death, the Harry W. Bass Jr. Research Foundation was merged with his late father's philanthropic foundation, the Harry Bass Foundation, to form the Harry W. Bass Jr. Foundation; the endowment comes from oil investments as well as the proceeds from auctions of his coin collection. For example, thirty coins from his collection were auctioned in 2014 in Dallas. Harry W. Bass Jr. at Find a Grave