Large flying fox
The large flying fox known as the greater flying fox, Malayan flying fox, Malaysian flying fox, large fruit bat, kalang or kalong, is a southeast Asian species of megabat in the family Pteropodidae. Like the other members of the genus Pteropus, or the Old World fruit bats, it feeds on fruits and flowers, it is noted for being one of the largest bats. As with nearly all other Old World fruit bats, it lacks the ability to echolocate but compensates for it with well-developed eyesight; the large flying fox was one of the many mammal species described by Linnaeus in the landmark 1758 10th edition of his Systema Naturae, receiving the name Vespertilio vampyrus. The large flying fox is among the largest species of bat, it weighs 0.65–1.1 kg and has a wingspan of up to 1.5 m. Its head-body length is 27–32 cm; as with all megabats, it has a fox-like face, hence its name. It has pointed ears; the hairs on much of its body are shorter and more erect on the upper back. The mantle hairs tend to be the longest.
The color and texture of the coat differ between sexes and age classes. Males tend to have stiffer and thicker coats than females. Immature individuals are all dull gray-brown. Young have a dark-colored mantle; the head has hairs that range in color from orange-ochreous to blackish. The ventral areas are tinged with chocolate, gray or silver; the mantle can vary from pale dirty-buff to orange-yellow, while the chest is dark-golden brown or dark russet. The large flying fox has a robust skull; the dental formula is 2.2.1.13.3.2.3. It has a total of 34 teeth; the large flying fox's wings are somewhat rounded at the tips. This allows them to fly but with great maneuverability; the wing membranes are only haired near the body. The large flying fox ranges from Malay Peninsula, to the Philippines in the east and Indonesian Archipelago of Sumatra, Java and Timor in the south. In certain areas, the bat prefers coastal regions, but it can be found at elevations up to 1,370 m. Flying foxes inhabit primary forest, mangrove forest, coconut groves, mixed fruit orchards, a number of other habitats.
During the day, trees in mangrove forests and coconut groves may be used as roosts. In Malaysia, flying foxes prefer lowland habitats below 365 m. In Borneo, they move to nearby islands to feed on fruit. Flying foxes roost in the thousands. One colony was recorded numbering around 2,000 individuals in a mangrove forest in Timor and colonies of 10,000-20,000 have been reported. In general, mangrove roosts have lower numbers of resting bats compared to lowland roost sites, which could mean mangrove forests are only used temporarily; this species feeds on flowers and fruit. When all three food items are available and nectar are preferred; the pollen and flower of coconut and durian trees, as well as the fruits of rambutan and langsat trees, are consumed. Flying foxes will eat mangoes and bananas. With fruit, the flying fox prefers the pulp, slices open the rind to get it. With durian tree flowers, the flying fox can lick up the nectar without doing apparent damage to the flower. Colonies of large flying foxes fly in a scattered stream.
They may fly up to 50 km to their feeding grounds in one night. Vocalizations are not made during flight. Large flocks fuse into feeding groups upon arrival at feeding grounds. Flying foxes may circle a fruit tree before landing, land on the tips of branches in an upright position fall into a head-down position from which they feed. Feeding aggregations tend to be noisy. Flowering trees form the basis of territories in this species. Territorial behavior includes the spreading of wings. During antagonistic behavior, individuals maintain spacing with wrists/thumbs sparring and loud vocalizations; when moving to a suitable resting place after landing, an individual may fight with conspecifics along the way. A roosting flying fox is positioned upside down with its wings wrapped up; when it gets too warm, a flying fox fans itself with its wings. Roosting bats are restless until midmorning. Female large flying fox gestations are at their highest between November to January in Peninsular Malaysia, but some births occur in other months.
In Thailand, gestation may take place during the same period with young being born in March or early April. Females give birth during April and May in the Philippines, give birth to only one young. For the first days, the mothers carry their young, but leave them at the roost when they go on their foraging trips; the young are weaned by two to three months. A recent update by the IUCN has listed the species as Near Threatened and mentioned its near-vulnerable status with the following reasons:... listed as Near Threatened because this species is in significant decline because it is being over-harvested for food over much of its range, because of ongoing degradation of its primary forest habitat, making the species close to qualifying for Vulnerable under criterion A. One threat to the large flying fox is habitat destruction. Flying foxes are sometimes hunted for food, the controls on hunting seem to be unenforceable. In some areas, farmers consider; this species is hunted for bushmeat in Indonesia, contributing to its decline.
View the Megabat genome in Ensembl
Bird
Birds known as Aves, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, a strong yet lightweight skeleton. Birds range in size from the 5 cm bee hummingbird to the 2.75 m ostrich. They rank as the world's most numerically-successful class of tetrapods, with ten thousand living species, more than half of these being passerines, sometimes known as perching birds. Birds have wings which are less developed depending on the species. Wings, which evolved from forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in flightless birds, including ratites and diverse endemic island species of birds; the digestive and respiratory systems of birds are uniquely adapted for flight. Some bird species of aquatic environments seabirds and some waterbirds, have further evolved for swimming; the fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier feathered dinosaurs within the theropod group, which are traditionally placed within the saurischian dinosaurs.
The closest living relatives of birds are the crocodilians. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period, around 170 million years ago. Many of these early "stem-birds", such as Archaeopteryx, were not yet capable of powered flight, many retained primitive characteristics like toothy jaws in place of beaks, long bony tails. DNA-based evidence finds that birds diversified around the time of the Cretaceous–Palaeogene extinction event 66 million years ago, which killed off the pterosaurs and all the non-avian dinosaur lineages, but birds those in the southern continents, survived this event and migrated to other parts of the world while diversifying during periods of global cooling. This makes them the sole surviving dinosaurs according to cladistics; some birds corvids and parrots, are among the most intelligent animals. Many species annually migrate great distances. Birds are social, communicating with visual signals and bird songs, participating in such social behaviours as cooperative breeding and hunting and mobbing of predators.
The vast majority of bird species are monogamous for one breeding season at a time, sometimes for years, but for life. Other species have breeding systems that are polygynous or polyandrous. Birds produce offspring by laying eggs, they are laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching; some birds, such as hens, lay eggs when not fertilised, though unfertilised eggs do not produce offspring. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs and feathers. Songbirds and other species are popular as pets. Guano is harvested for use as a fertiliser. Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them.
Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae. Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system in use. Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda. Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria. During the late 1990s, Aves was most defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica. However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, is used by many scientists including adherents of the Phylocode system. Gauthier defined Aves to include only the crown group of the set of modern birds; this was done by excluding most groups known only from fossils, assigning them, instead, to the Avialae, in part to avoid the uncertainties about the placement of Archaeopteryx in relation to animals traditionally thought of as theropod dinosaurs.
Gauthier identified four different definitions for the same biological name "Aves", a problem. Gauthier proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below, he assigned other names to the other groups. Aves can mean all archosaurs closer to birds than to crocodiles Aves can mean those advanced archosaurs with feathers Aves can mean those feathered dinosaurs that fly Aves can mean the last common ancestor of all the living birds and all of its descendants (a "c
Ornithopter
An ornithopter is an aircraft that flies by flapping its wings. Designers seek to imitate the flapping-wing flight of birds and insects. Though machines may differ in form, they are built on the same scale as these flying creatures. Manned ornithopters have been built, some have been successful; the machines are of two general types: those with engines, those powered by the muscles of the pilot. Some early manned flight attempts may have been intended to achieve flapping-wing flight, though only a glide was achieved; these include the purported flights of the 11th-century monk Eilmer of Malmesbury and the 9th-century poet Abbas Ibn Firnas. Roger Bacon, writing in 1260, was among the first to consider a technological means of flight. In 1485, Leonardo da Vinci began to study the flight of birds, he grasped that humans are too heavy, not strong enough, to fly using wings attached to the arms. He therefore sketched a device in which the aviator lies down on a plank and works two large, membranous wings using hand levers, foot pedals, a system of pulleys.
In 1841, an ironsmith kalfa Manojlo who "came to Belgrade from Vojvodina" attempted flying with a device described as an ornithopter. Refused by the authorities a permit to take off from the belfry of Belgrade Serbian Orthodox Cathedral, he clandestinely climbed to the rooftop of the Dumrukhana and took off, landing in a heap of snow, surviving; the first ornithopters capable of flight were constructed in France. Jobert in 1871 used a rubber band to power a small model bird. Alphonse Pénaud, Abel Hureau de Villeneuve, Victor Tatin made rubber-powered ornithopters during the 1870s. Tatin's ornithopter was the first to use active torsion of the wings, it served as the basis for a commercial toy offered by Pichancourt circa 1889. Gustave Trouvé was the first to use internal combustion, his 1890 model flew a distance of 80 metres in a demonstration for the French Academy of Sciences; the wings were flapped by gunpowder charges activating a Bourdon tube. From 1884 on, Lawrence Hargrave built scores of ornithopters powered by rubber bands, steam, or compressed air.
He introduced the use of small flapping wings providing the thrust for a larger fixed wing. E. P. Frost made ornithopters starting in the 1870s. In the 1930s, Alexander Lippisch and the NSFK in Germany constructed and flew a series of internal combustion-powered ornithopters, using Hargrave's concept of small flapping wings, but with aerodynamic improvements resulting from methodical study. Erich von Holst working in the 1930s, achieved great efficiency and realism in his work with ornithopters powered by rubber bands, he achieved the first success of an ornithopter with a bending wing, intended to imitate more the folding wing action of birds, although it was not a true variable-span wing like those of birds. Around 1960, Percival Spencer flew a series of unmanned ornithopters using internal combustion engines ranging from 0.020-to-0.80-cubic-inch displacement, having wingspans up to 8 feet. In 1961, Percival Spencer and Jack Stephenson flew the first successful engine-powered, remotely piloted ornithopter, known as the Spencer Orniplane.
The Orniplane had a 90.7-inch wingspan, weighed 7.5 pounds, was powered by a 0.35-cubic-inch -displacement two-stroke engine. It had a biplane configuration. Manned ornithopters fall into two general categories: Those powered by the muscular effort of the pilot, those powered by an engine. Around 1894, Otto Lilienthal, an aviation pioneer, became famous in Germany for his publicized and successful glider flights. Lilienthal studied bird flight and conducted some related experiments, he constructed an ornithopter, although its complete development was prevented by his untimely death on 9 August 1896 in a glider accident. In 1929, a man-powered ornithopter designed by Alexander Lippisch flew a distance of 250 to 300 metres after tow launch. Since a tow launch was used, some have questioned whether the aircraft was capable of flying on its own. Lippisch asserted that the aircraft was flying, not making an extended glide. Most of the subsequent human-powered ornithopters used a tow launch, flights were brief because human muscle power diminishes over time.
In 1942, Adalbert Schmid made a much longer flight of a human-powered ornithopter at Munich-Laim. It travelled a distance of 900 metres, maintaining a height of 20 metres throughout most of the flight; this same aircraft was fitted with a three-horsepower Sachs motorcycle engine. With the engine, it made flights up to 15 minutes in duration. Schmid constructed a 10-horsepower ornithopter, based on the Grunau-Baby IIa sailplane, flown in 1947; the second aircraft had flapping outer wing panels. In 2005, Yves Rousseau was given the Paul Tissandier Diploma, awarded by the FAI for contributions to the field of aviation. Rousseau attempted his first human-muscle-powered flight with flapping wings in 1995. On 20 April 2006, at
Helicopter rotor
A helicopter main rotor or rotor system is the combination of several rotary wings and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, the thrust that counteracts aerodynamic drag in forward flight. Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which connects through a combination of drive shaft and gearboxes along the tail boom; the blade pitch is controlled by a swashplate connected to the helicopter flight controls. Helicopters are one example of rotary-wing aircraft; the name is derived from meaning spiral. The use of a rotor for vertical flight has existed since 400 BC in the form of the bamboo-copter, an ancient Chinese toy; the bamboo-copter is spun by rolling a stick attached to a rotor. The spinning creates lift, the toy flies when released; the philosopher Ge Hong's book the Baopuzi, written around 317, describes the apocryphal use of a possible rotor in aircraft: "Some have made flying cars with wood from the inner part of the jujube tree, using ox-leather fastened to returning blades so as to set the machine in motion."
Leonardo da Vinci designed a machine known as an "aerial screw" with a rotor based on a water screw. The Russian polymath Mikhail Lomonosov developed a rotor based on the Chinese toy; the French naturalist Christian de Launoy constructed his rotor out of turkey feathers. Sir George Cayley, inspired by the Chinese toy in his childhood, created multiple vertical flight machines with rotors made of tin sheets. Alphonse Pénaud would develop the coaxial rotor model helicopter toys in 1870, powered by rubber bands. One of these toys, given as a gift by their father, would inspire the Wright brothers to pursue the dream of flight. Before development of powered helicopters in the mid 20th century, autogyro pioneer Juan de la Cierva researched and developed many of the fundamentals of the rotor. De la Cierva is credited with successful development of multi-bladed articulated rotor systems; this system, in its various modified forms, is the basis of most multi-bladed helicopter rotor systems. The first successful attempt at a single-lift rotor helicopter design used a four-blade main rotor, as designed by Soviet aeronautical engineers Boris N. Yuriev and Alexei M. Cheremukhin, both working at the Tsentralniy Aerogidrodinamicheskiy Institut near Moscow in the early 1930s.
Their TsAGI 1-EA helicopter was able to fly in low altitude testing in 1931-32, with Cheremukhin flying it as high as 605 meters by mid-August 1932. In the 1930s, Arthur Young improved the stability of two-bladed rotor systems with the introduction of a stabilizer bar; this system was used in several Hiller helicopter models. The Hiller system variant using airfoiled paddles at the flybar's ends has been used in many of the earliest designs of remote control model helicopters, from their 1970s origins onwards to the early 21st century. In the late 1940s, the making of helicopter rotor blades was a job that inspired John T. Parsons to be a pioneer of numerical control. NC and CNC turned out to be an important new technology that affected all machining industries; the helicopter rotor is powered through the transmission, to the rotating mast. The mast is a cylindrical metal shaft. At the top of the mast is the attachment point for the rotor blades called the hub; the rotor blades are attached to the hub, the hub can have 10-20 times the drag of the blade.
Main rotor systems are classified according to how the main rotor blades are attached and move relative to the main rotor hub. There are three basic classifications: hingeless and articulated, although some modern rotor systems use a combination of these classifications. A rotor is a finely tuned rotating mass, different subtle adjustments reduce vibrations at different airspeeds; the rotors are designed to operate at a fixed RPM, but a few experimental aircraft used variable speed rotors. Unlike the small diameter fans used in turbofan jet engines, the main rotor on a helicopter has a large diameter that lets it accelerate a large volume of air; this permits a lower downwash velocity for a given amount of thrust. As it is more efficient at low speeds to accelerate a large amount of air by a small degree than a small amount of air by a large degree, a low disc loading increases the aircraft's energy efficiency, this reduces the fuel use and permits reasonable range; the hover efficiency of a typical helicopter is around 60%.
The inner third length of a rotor blade contributes little to lift due to its low airspeed. The simple rotor of a Robinson R22 showing: The following are driven by the link rods from the rotating part of the swashplate. Pitch hinges, allowing the blades to twist about the axis extending from blade root to blade tip. Teeter hinge, allowing one blade to rise vertically; this motion occurs whenever translational relative wind is present, or in response to a cyclic control input. Scissor link and counterweight, carries the main shaft rotation down to the upper swashplate Rubber covers protect moving and stationary shafts Swashplates, transmitting cyclic and collective pitch to the blades Three non-rotating control rods transmit pitch information to the lower swashplate Main mast leading down to main gearbox Controls vary the pitch of the main rotor blades cyclically throughout rotation; the p
Moment of inertia
The moment of inertia, otherwise known as the angular mass or rotational inertia, of a rigid body is a quantity that determines the torque needed for a desired angular acceleration about a rotational axis. It depends on the body's mass distribution and the axis chosen, with larger moments requiring more torque to change the body's rotation rate, it is an extensive property: for a point mass the moment of inertia is just the mass times the square of the perpendicular distance to the rotation axis. The moment of inertia of a rigid composite system is the sum of the moments of inertia of its component subsystems, its simplest definition is the second moment of mass with respect to distance from an axis. For bodies constrained to rotate in a plane, only their moment of inertia about an axis perpendicular to the plane, a scalar value, matters. For bodies free to rotate in three dimensions, their moments can be described by a symmetric 3 × 3 matrix, with a set of mutually perpendicular principal axes for which this matrix is diagonal and torques around the axes act independently of each other.
When a body is free to rotate around an axis, torque must be applied to change its angular momentum. The amount of torque needed to cause any given angular acceleration is proportional to the moment of inertia of the body. Moment of inertia may be expressed in units of kilogram meter squared in SI units and pound-foot-second squared in imperial or US units. Moment of inertia plays the role in rotational kinetics that mass plays in linear kinetics - both characterize the resistance of a body to changes in its motion; the moment of inertia depends on how mass is distributed around an axis of rotation, will vary depending on the chosen axis. For a point-like mass, the moment of inertia about some axis is given by m r 2, where r is the distance of the point from the axis, m is the mass. For an extended rigid body, the moment of inertia is just the sum of all the small pieces of mass multiplied by the square of their distances from the axis in question. For an extended body of a regular shape and uniform density, this summation sometimes produces a simple expression that depends on the dimensions and total mass of the object.
In 1673 Christiaan Huygens introduced this parameter in his study of the oscillation of a body hanging from a pivot, known as a compound pendulum. The term moment of inertia was introduced by Leonhard Euler in his book Theoria motus corporum solidorum seu rigidorum in 1765, it is incorporated into Euler's second law; the natural frequency of oscillation of a compound pendulum is obtained from the ratio of the torque imposed by gravity on the mass of the pendulum to the resistance to acceleration defined by the moment of inertia. Comparison of this natural frequency to that of a simple pendulum consisting of a single point of mass provides a mathematical formulation for moment of inertia of an extended body. Moment of inertia appears in momentum, kinetic energy, in Newton's laws of motion for a rigid body as a physical parameter that combines its shape and mass. There is an interesting difference in the way moment of inertia appears in planar and spatial movement. Planar movement has a single scalar that defines the moment of inertia, while for spatial movement the same calculations yield a 3 × 3 matrix of moments of inertia, called the inertia matrix or inertia tensor.
The moment of inertia of a rotating flywheel is used in a machine to resist variations in applied torque to smooth its rotational output. The moment of inertia of an airplane about its longitudinal and vertical axis determines how steering forces on the control surfaces of its wings and tail affect the plane in roll and yaw. Moment of inertia I is defined as the ratio of the net angular momentum L of a system to its angular velocity ω around a principal axis, I = L ω. If the angular momentum of a system is constant as the moment of inertia gets smaller, the angular velocity must increase; this occurs when spinning figure skaters pull in their outstretched arms or divers curl their bodies into a tuck position during a dive, to spin faster. If the shape of the body does not change its moment of inertia appears in Newton's law of motion as the ratio of an applied torque τ on a body to the angular acceleration α around a principal axis, τ = I α. For a simple pendulum, this definition yields a formula for the moment of inertia I in terms of the mass m of the pendulum and its distance r from the pivot point as, I = m r 2.
Thus, moment of inertia depends on both the mass m of a body and its geometry, or shape, as defined by the distance r to the axis of rotation. This simple formula generalizes to define moment of inertia for an arbitrarily shaped body as the sum of all the elemental point masses d m each multiplied by the square of its perpendicular distance
Pterosaur
Pterosaurs were flying reptiles of the extinct clade or order Pterosauria. They existed during most of the Mesozoic: from the late Triassic to the end of the Cretaceous. Pterosaurs are the earliest vertebrates known to have evolved powered flight, their wings were formed by a membrane of skin and other tissues stretching from the ankles to a lengthened fourth finger. Early species had long toothed jaws and long tails, while forms had a reduced tail, some lacked teeth. Many sported furry coats made up of hair-like filaments known as pycnofibers, which covered their bodies and parts of their wings. Pterosaurs spanned a wide range of adult sizes, from the small anurognathids to the largest known flying creatures of all time, including Quetzalcoatlus and Hatzegopteryx. Pterosaurs are referred to in the popular media and by the general public as "flying dinosaurs", but the term "dinosaur" is restricted to just those reptiles descended from the last common ancestor of the groups Saurischia and Ornithischia, current scientific consensus is that this group excludes the pterosaurs, as well as the various groups of extinct marine reptiles, such as ichthyosaurs and mosasaurs.
Unlike these other reptiles, pterosaurs are nonetheless more related to birds and dinosaurs than to crocodiles or any other living reptile. Pterosaurs are colloquially referred to as pterodactyls in fiction and by journalists. However, pterodactyl only refers to members of the genus Pterodactylus, more broadly to members of the suborder Pterodactyloidea of the pterosaurs; the anatomy of pterosaurs was modified from their reptilian ancestors by the adaption to flight. Pterosaur bones were air-filled, like the bones of birds, they had a keeled breastbone, developed for the attachment of flight muscles and an enlarged brain that shows specialised features associated with flight. In some pterosaurs, the backbone over the shoulders fused into a structure known as a notarium, which served to stiffen the torso during flight, provide a stable support for the shoulder blade. Pterosaur wings were formed by membranes of skin and other tissues; the primary membranes attached to the long fourth finger of each arm and extended along the sides of the body to the ankles.
While thought of as simple leathery structures composed of skin, research has since shown that the wing membranes of pterosaurs were complex dynamic structures suited to an active style of flight. The outer wings were strengthened by spaced fibers called actinofibrils; the actinofibrils themselves consisted of three distinct layers in the wing, forming a crisscross pattern when superimposed on one another. The function of the actinofibrils is unknown. Depending on their exact composition, they may have been stiffening or strengthening agents in the outer part of the wing; the wing membranes contained a thin layer of muscle, fibrous tissue, a unique, complex circulatory system of looping blood vessels. As shown by cavities in the wing bones of larger species and soft tissue preserved in at least one specimen, some pterosaurs extended their system of respiratory air sacs into the wing membrane; the pterosaur wing membrane is divided into three basic units. The first, called the propatagium, was the forward-most part of the wing and attached between the wrist and shoulder, creating the "leading edge" during flight.
This membrane may have incorporated the first three fingers of the hand, as evidenced in some specimens. The brachiopatagium was the primary component of the wing, stretching from the elongated fourth finger of the hand to the hind limbs. At least some pterosaur groups had a membrane that stretched between the legs connecting to or incorporating the tail, called the uropatagium, it is agreed though that non-pterodactyloid pterosaurs had a broader uro/cruropatagium, with pterodactyloids only having membranes running along the legs. A bone unique to pterosaurs, known as the pteroid, connected to the wrist and helped to support a forward membrane between the wrist and shoulder. Evidence of webbing between the three free fingers of the pterosaur forelimb suggests that this forward membrane may have been more extensive than the simple pteroid-to-shoulder connection traditionally depicted in life restorations; the position of the pteroid bone itself has been controversial. Some scientists, notably Matthew Wilkinson, have argued that the pteroid pointed forward, extending the forward membrane.
This view was contradicted in a 2007 paper by Chris Bennett, who showed that the pteroid did not articulate as thought and could not have pointed forward, but rather inward toward the body as traditionally thought. Peters proposed that the pteroid articulated with the ‘saddle' of the radiale and both the pteroid and preaxial carpal were migrated centralia; this view of the articulation of the pteroid has since been supported by specimens of Changchengopterus pani and Darwinopterus linglongtaensis, both of which show the pteroid in articulation with the proximal syncarpal. The pterosaur
The Washington Post
The Washington Post is a major American daily newspaper published in Washington, D. C. with a particular emphasis on national politics and the federal government. It has the largest circulation in the Washington metropolitan area, its slogan "Democracy Dies in Darkness" began appearing on its masthead in 2017. Daily broadsheet editions are printed for the District of Columbia and Virginia; the newspaper has won 47 Pulitzer Prizes. This includes six separate Pulitzers awarded in 2008, second only to The New York Times' seven awards in 2002 for the highest number awarded to a single newspaper in one year. Post journalists have received 18 Nieman Fellowships and 368 White House News Photographers Association awards. In the early 1970s, in the best-known episode in the newspaper's history, reporters Bob Woodward and Carl Bernstein led the American press' investigation into what became known as the Watergate scandal, their reporting in The Washington Post contributed to the resignation of President Richard Nixon.
In years since, the Post's investigations have led to increased review of the Walter Reed Army Medical Center. In October 2013, the paper's longtime controlling family, the Graham family, sold the newspaper to Nash Holdings, a holding company established by Jeff Bezos, for $250 million in cash; the Washington Post is regarded as one of the leading daily American newspapers, along with The New York Times, the Los Angeles Times, The Wall Street Journal. The Post has distinguished itself through its political reporting on the workings of the White House and other aspects of the U. S. government. Unlike The New York Times and The Wall Street Journal, The Washington Post does not print an edition for distribution away from the East Coast. In 2009, the newspaper ceased publication of its National Weekly Edition, which combined stories from the week's print editions, due to shrinking circulation; the majority of its newsprint readership is in the District of Columbia and its suburbs in Maryland and Northern Virginia.
The newspaper is one of a few U. S. newspapers with foreign bureaus, located in Beirut, Beijing, Bogotá, Hong Kong, Jerusalem, London, Mexico City, Nairobi, New Delhi and Tokyo. In November 2009, it announced the closure of its U. S. regional bureaus—Chicago, Los Angeles and New York—as part of an increased focus on "political stories and local news coverage in Washington." The newspaper has local bureaus in Virginia. As of May 2013, its average weekday circulation was 474,767, according to the Audit Bureau of Circulations, making it the seventh largest newspaper in the country by circulation, behind USA Today, The Wall Street Journal, The New York Times, the Los Angeles Times, the Daily News, the New York Post. While its circulation has been slipping, it has one of the highest market-penetration rates of any metropolitan news daily. For many decades, the Post had its main office at 1150 15th Street NW; this real estate remained with Graham Holdings when the newspaper was sold to Jeff Bezos' Nash Holdings in 2013.
Graham Holdings sold 1150 15th Street for US$159 million in November 2013. The Washington Post continued to lease space at 1150 L Street NW. In May 2014, The Washington Post leased the west tower of One Franklin Square, a high-rise building at 1301 K Street NW in Washington, D. C; the newspaper moved into their new offices December 14, 2015. The Post has its own exclusive zip code, 20071. Arc Publishing is a department of the Post, which provides the publishing system, software for news organizations such as the Chicago Tribune and the Los Angeles Times; the newspaper was founded in 1877 by Stilson Hutchins and in 1880 added a Sunday edition, becoming the city's first newspaper to publish seven days a week. In 1889, Hutchins sold the newspaper to Frank Hatton, a former Postmaster General, Beriah Wilkins, a former Democratic congressman from Ohio. To promote the newspaper, the new owners requested the leader of the United States Marine Band, John Philip Sousa, to compose a march for the newspaper's essay contest awards ceremony.
Sousa composed "The Washington Post". It became the standard music to accompany the two-step, a late 19th-century dance craze, remains one of Sousa's best-known works. In 1893, the newspaper moved to a building at 14th and E streets NW, where it would remain until 1950; this building combined all functions of the newspaper into one headquarters – newsroom, advertising and printing – that ran 24 hours per day. In 1898, during the Spanish–American War, the Post printed Clifford K. Berryman's classic illustration Remember the Maine, which became the battle-cry for American sailors during the War. In 1902, Berryman published another famous cartoon in the Post—Drawing the Line in Mississippi; this cartoon depicts President Theodore Roosevelt showing compassion for a small bear cub and inspired New York store owner Morris Michtom to create the teddy bear. Wilkins acquired Hatton's share of the newspaper in 1894 at Hatton's death. After Wilkins' death in 1903, his sons John and Robert ran the Post for two years before selling it in 1905 to John Roll McLean, owner of the Cincinnati Enquirer.
During the Wilson presidency, the Post was credited with the "most famous newspaper typo" in D. C. history according to Reason magazine. When John McLean died in 1916, he put the newspap
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