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Wapping

Wapping is a district in East London in the London Borough of Tower Hamlets and uniquely has it own postcode area E1W, which covers the entire area. It is situated between the north bank of the River Thames and the ancient thoroughfare called The Highway. Wapping's proximity to the river has given it a strong maritime character, which it retains through its riverside public houses and steps, such as the Prospect of Whitby and Wapping Stairs, it has a Royal Navy shore establishment base on the riverfront called HMS President and home to Tobacco Dock and King Edward Memorial Park. Many of the original buildings were demolished during the construction of the London Docks and Wapping was further damaged during the Blitz; as the London Docklands declined after the Second World War, the area became run down, with the great warehouses left empty. The area's fortunes were transformed during the 1980s by the London Docklands Development Corporation when the warehouses started to be converted into luxury flats.

Rupert Murdoch moved his News International printing and publishing works into Wapping in 1986, resulting in a trade union dispute that became known as the "Battle of Wapping". It was believed that the name Wapping recorded an Anglo-Saxon settlement linked to a personal name Waeppa More recent scholarship discounts that theory: the area was marshland, where early settlement was unlikely, no such personal name has been found, it is now thought that the name may derive from a marsh. The settlement developed along the embankment of the Thames, hemmed in by the river to the south and the now-drained Wapping Marsh to the north; this gave it a peculiarly narrow and constricted shape, consisting of little more than the axis of Wapping High Street and some north–south side streets. John Stow, the 16th-century historian, described it as a "continual street, or a filthy strait passage, with alleys of small tenements or cottages, inhabited by sailors' victuallers". A chapel to St. John the Baptist was built in 1617, it was here that Thomas Rainsborough was buried.

Wapping was constituted as a parish in 1694 Wapping's proximity to the river gave it a strong maritime character for centuries, well into the 20th century. It was inhabited by sailors, boat-builders, instrument-makers and representatives of all the other trades that supported the seafarer. Wapping was the site of'Execution Dock', where pirates and other water-borne criminals faced execution by hanging from a gibbet constructed close to the low water mark, their bodies would be left dangling. The Bell Inn, by the execution dock, was run by Samuel Batts, whose daughter, married James Cook at St Margaret's Church, Essex on 21 December 1762, after the Royal Navy captain had stayed at the Inn; the couple settled in Shadwell, attending St Paul's church, but moved to Mile End. Although they had six children together, much of their married life was spent apart, with Cook absent on his voyages and, after his murder in 1779 at Kealakekua Bay, she survived until 1835. Said to be England's first, the Marine Police Force was formed in 1798 by magistrate Patrick Colquhoun and a Master Mariner, John Harriott, to tackle theft and looting from ships anchored in the Pool of London and the lower reaches of the river.

Its base was in Wapping High Street and it is now known as the Marine Support Unit. The Thames Police Museum, dedicated to the history of the Marine Police Force, is housed within the headquarters of the Marine Support Unit, is open to the public by appointment. In 1811, the Ratcliff Highway murders took place nearby at the Wapping Lane; the area's strong maritime associations changed radically in the 19th century when the London Docks were built to the north and west of the High Street. Wapping's population plummeted by nearly 60% during that century, with many houses destroyed by the construction of the docks and giant warehouses along the riverfront. Squeezed between the high walls of the docks and warehouses, the district became isolated from the rest of London, although some relief was provided by Brunel's Thames Tunnel to Rotherhithe; the opening of Wapping tube station on the East London Line in 1869 provided a direct rail link to the rest of London. Wapping was devastated by German bombing in the Second World War and by the post-war closure of the docks.

It remained a run-down and derelict area into the 1980s, when the area was transferred to the management of the London Docklands Development Corporation, a government quango with the task of redeveloping the Docklands. The London Docks were filled in and redeveloped with a variety of commercial, light industrial and residential properties. St John's Church was located on. Only the tower and shell survived wartime bombing, have now been converted to housing. In 1986, Rupert Murdoch's News International built a new £80m printing and publishing works in the north of Wapping; this became the scene of violent protests after News International's UK operation moved from Fleet Street to Wapping, with over 5,000 print workers being sacked when new technology was introduced. The "Wapping dispute" or "Battle of Wapping" was, along with the miners' strike of 1984-85, a significant turning point in the history of the trade union movement and of UK industrial relations, it started on 24 January 1986 when some 6,000 newspaper workers went on strike after protracted negotiation with their employer, News International.

News International had built and clandestinely equipped a new printing

Karenites

Karenites is an extinct genus of therocephalian therapsids from the Late Permian of Russia. The only species is Karenites ornamentatus, named in 1995. Several fossil specimens are known from the town of Kotelnich in Kirov Oblast. Karenites is known from a partial holotype skeleton, two partial skulls, isolated jaw bones. Although incomplete, the skulls preserve small and delicate structures like nasal turbinates on the inside of the skull and the stapes bone of the ear; the skull of Karenites is about 10 centimetres long, with the snout much longer than the temporal region of the skull behind the eye sockets. Viewed from above, the skull is triangular; the snout is broad, the skull widens toward the occiput or posterior margin. Two large holes behind the eye socket called temporal fenestrae occupy most of the posterior skull. Between these fenestra is a narrow sagittal crest. In front of this crest, the skull roof bones are weakly pitted with small bumps and ridges for blood vessels; some specimens include parts of a ring of bone embedded in the eye.

On each side of the upper jaw are five incisors, two or three precanines, one canine, eleven or twelve postcanines. The incisors and precanines are long and curved, separated from each other by a small gap; the canine is much longer, projecting forward from the tooth socket and curving backward along its length. The postcanine teeth are broader than the incisors and precanines. Toward the back of the skull the tips of the teeth flatten; the lower jaw is thin and curves upward to the arch of the cheek, except for a large coronoid process that extends to the articular-quadrate jaw joint at the back of the skull. The lower jaw has three small incisors angled forward, a large canine tooth projecting upward, thirteen small, blunt postcanine teeth; the farthest postcanine teeth have small secondary cusps behind their tips. These multicusped teeth may have been adaptations for crushing food, although they are not as well developed as the teeth of other therocephalians like Ericiolacerta. In 1999, thoracic plates were reported to be present in the holotype of Karenites.

Thoracic plates are plates of bone on the underside of the rib cage that are found in reptiles, unusual for mammal relatives like therocephalians. This bone was reinterpreted as an interclavicle, part of the pectoral girdle common to all early therapsids; the presence of a sclerotic ring in Karenites may be an indication. Pits on the skull have been interpreted as evidence for well-developed whiskers, which may have been used in hunting aquatic prey; some therocephalians like Perplexisaurus have been interpreted as aquatic predators, share many similarities with Karenites. While these aquatic forms had strong sutures between cranial bones, which may have stabilized the skull when consuming large aquatic prey like fishes, Karenites had weaker movable skull joints associated with feeding on smaller terrestrial prey like insects, its multicuspid teeth suggest it fed on insects. Karenites has long limb bones that indicate a terrestrial rather than aquatic lifestyle. Ridges on the inside of the skull of Karenites form a series of sinuses.

These sinuses may have been associated with improvements in the sense of smell of therocephalians, but they are not thought to be olfactory structures. Bony projections on the underside of the lower jaw of Karenites may have supported tissues that transmitted sound to the stapes bone in the ear. Early therapsids like Karenites lack the well-developed auditory system of mammals, which had evolved from a restructuring of bones in the back of the skull and the lower jaw, had a poor sense of hearing; as an early stage in the development of the mammalian auditory system, Karenites may have been able to hear some sounds by placing its jaw on the ground to detect vibrations

Diffraction-limited system

The resolution of an optical imaging system – a microscope, telescope, or camera – can be limited by factors such as imperfections in the lenses or misalignment. However, there is a principal limit to the resolution of any optical system, due to the physics of diffraction. An optical system with resolution performance at the instrument's theoretical limit is said to be diffraction-limited; the diffraction-limited angular resolution of a telescopic instrument is proportional to the wavelength of the light being observed, inversely proportional to the diameter of its objective's entrance aperture. For telescopes with circular apertures, the size of the smallest feature in an image, diffraction limited is the size of the Airy disk; as one decreases the size of the aperture of a telescopic lens, diffraction proportionately increases. At small apertures, such as f/22, most modern lenses are limited only by diffraction and not by aberrations or other imperfections in the construction. For microscopic instruments, the diffraction-limited spatial resolution is proportional to the light wavelength, to the numerical aperture of either the objective or the object illumination source, whichever is smaller.

In astronomy, a diffraction-limited observation is one that achieves the resolution of a theoretically ideal objective in the size of instrument used. However, most observations from Earth are seeing-limited due to atmospheric effects. Optical telescopes on the Earth work at a much lower resolution than the diffraction limit because of the distortion introduced by the passage of light through several kilometres of turbulent atmosphere; some advanced observatories have started using adaptive optics technology, resulting in greater image resolution for faint targets, but it is still difficult to reach the diffraction limit using adaptive optics. Radiotelescopes are diffraction-limited, because the wavelengths they use are so long that the atmospheric distortion is negligible. Space-based telescopes always work at their diffraction limit, if their design is free of optical aberration; the beam from a laser with near-ideal beam propagation properties may be described as being diffraction-limited.

A diffraction-limited laser beam, passed through diffraction-limited optics, will remain diffraction-limited, will have a spatial or angular extent equal to the resolution of the optics at the wavelength of the laser. The observation of sub-wavelength structures with microscopes is difficult because of the Abbe diffraction limit. Ernst Abbe found in 1873 that light with wavelength λ, traveling in a medium with refractive index n and converging to a spot with half-angle θ will have a minimum resolvable distance of d = λ 2 n sin ⁡ θ = λ 2 N A The portion of the denominator n sin ⁡ θ is called the numerical aperture and can reach about 1.4–1.6 in modern optics, hence the Abbe limit is d = λ/2.8. Considering green light around 500 nm and a NA of 1, the Abbe limit is d = λ/2 = 250 nm, small compared to most biological cells, but large compared to viruses and less complex molecules. To increase the resolution, shorter wavelengths can be used such as X-ray microscopes; these techniques offer better resolution but are expensive, suffer from lack of contrast in biological samples and may damage the sample.

In a digital camera, diffraction effects interact with the effects of the regular pixel grid. The combined effect of the different parts of an optical system is determined by the convolution of the point spread functions; the point spread function of a diffraction limited lens is the Airy disk. The point spread function of the camera, otherwise called the instrument response function can be approximated by a rectangle function, with a width equivalent to the pixel pitch. A more complete derivation of the modulation transfer function of image sensors is given by Fliegel. Whatever the exact instrument response function, it is independent of the f-number of the lens, thus at different f-numbers a camera may operate in three different regimes, as follows: In the case where the spread of the IRF is small with respect to the spread of the diffraction PSF, in which case the system may be said to be diffraction limited. In the case where the spread of the diffraction PSF is small with respect to the IRF, in which case the system is instrument limited.

In the case where the spread of the PSF and IRF are of the same order of magnitude, in which case both impact the available resolution of the system. The spread of the diffraction-limited PSF is approximated by the diameter of the first null of the Airy disk, d / 2 = 1.22 λ N, where λ is the wavelength of the light and N is the f-number of the imaging optics. For f/8 and green light, d = 9.76 μm. This is of the same order of magnitude as the pixel size for the majority of commercially available'full frame' cameras and so these will operate in regime 3 for f-numbers around 8. Cameras with smaller sensors will tend to have smaller pixels, but their lense