click links in text for more info
SUMMARY / RELATED TOPICS

Gamma-ray burst

In gamma-ray astronomy, gamma-ray bursts are energetic explosions that have been observed in distant galaxies. They are the brightest electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several hours. After an initial flash of gamma rays, a longer-lived "afterglow" is emitted at longer wavelengths; the intense radiation of most observed GRBs is thought to be released during a supernova or superluminous supernova as a high-mass star implodes to form a neutron star or a black hole. A subclass of GRBs appear to originate from the merger of binary neutron stars; the cause of the precursor burst observed in some of these short events may be the development of a resonance between the crust and core of such stars as a result of the massive tidal forces experienced in the seconds leading up to their collision, causing the entire crust of the star to shatter. The sources of most GRBs are billions of light years away from Earth, implying that the explosions are both energetic and rare.

All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way. It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event. GRBs were first detected in 1967 by the Vela satellites, designed to detect covert nuclear weapons tests. Following their discovery, hundreds of theoretical models were proposed to explain these bursts, such as collisions between comets and neutron stars. Little information was available to verify these models until the 1997 detection of the first X-ray and optical afterglows and direct measurement of their redshifts using optical spectroscopy, thus their distances and energy outputs; these discoveries, subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs, definitively placing them in distant galaxies.

Gamma-ray bursts were first observed in the late 1960s by the U. S. Vela satellites, which were built to detect gamma radiation pulses emitted by nuclear weapons tested in space; the United States suspected that the Soviet Union might attempt to conduct secret nuclear tests after signing the Nuclear Test Ban Treaty in 1963. On July 2, 1967, at 14:19 UTC, the Vela 4 and Vela 3 satellites detected a flash of gamma radiation unlike any known nuclear weapons signature. Uncertain what had happened but not considering the matter urgent, the team at the Los Alamos National Laboratory, led by Ray Klebesadel, filed the data away for investigation; as additional Vela satellites were launched with better instruments, the Los Alamos team continued to find inexplicable gamma-ray bursts in their data. By analyzing the different arrival times of the bursts as detected by different satellites, the team was able to determine rough estimates for the sky positions of sixteen bursts and definitively rule out a terrestrial or solar origin.

The discovery was declassified and published in 1973. Most early theories of gamma-ray bursts posited nearby sources within the Milky Way Galaxy. From 1991, the Compton Gamma Ray Observatory and its Burst and Transient Source Explorer instrument, an sensitive gamma-ray detector, provided data that showed the distribution of GRBs is isotropic—not biased towards any particular direction in space. If the sources were from within our own galaxy they would be concentrated in or near the galactic plane; the absence of any such pattern in the case of GRBs provided strong evidence that gamma-ray bursts must come from beyond the Milky Way. However, some Milky Way models are still consistent with an isotropic distribution. In October 2018, astronomers reported that GRB 150101B, a gamma-ray burst event detected in 2015, may be directly related to the historic GW170817, a gravitational wave event detected in 2017, associated with the merger of two neutron stars; the similarities between the two events, in terms of gamma ray, optical and x-ray emissions, as well as to the nature of the associated host galaxies, are "striking", suggesting the two separate events may both be the result of the merger of neutron stars, both may be a kilonova, which may be more common in the universe than understood, according to the researchers.

In November 2019, astronomers reported a notable gamma ray burst explosion, named GRB 190114C detected in January 2019, that, so far, has been determined to have had the highest energy, 1 Tera electron volts observed for such a cosmic event. For decades after the discovery of GRBs, astronomers searched for a counterpart at other wavelengths: i.e. any astronomical object in positional coincidence with a observed burst. Astronomers considered many distinct classes of objects, including white dwarfs, supernovae, globular clusters, Seyfert galaxies, BL Lac objects. All such searches were unsuccessful, in a few cases well-localized bursts could be shown to have no bright objects of any nature consistent with the position derived from the detecting satellites; this suggested an origin of either faint stars or distant galaxies. The most accurate positions contained numerous faint stars and galaxies, it was agreed that final resolution of the origins of cosmic gamma-ray bursts wo

Škorpion

The Škorpion vz. 61 is a Czechoslovak machine pistol developed in 1959 by Miroslav Rybář and produced under the official designation Samopal vzor 61 by the Česká zbrojovka arms factory in Uherský Brod from 1961 to 1979. Although it was developed for use with security forces, the weapon was accepted into service with the Czechoslovak Army as a personal sidearm for lower-ranking army staff, vehicle drivers, armoured vehicle personnel and special forces; the weapon is in use with the armed forces of several countries as a sidearm. The Škorpion was licence-built in Yugoslavia, designated M84, it features a synthetic pistol grip in place of the wooden original. A civilian, semi-automatic version was produced, known as the M84A available in.380 ACP. The Škorpion was developed in the late 1950s by Miroslav Rybář with the working name "model 59"; the design was completed in 1961 and named "Samopal Vz. 61". It was subsequently adopted by the Czechoslovak Army and security forces, exported to various countries.

Yugoslavia produced a version under licence. It was used by armed groups, including the Irish Republican Army, Irish National Liberation Army and the Italian Red Brigades; the latter used the Škorpion during the 1978 kidnapping of Aldo Moro using this weapon to kill Moro. In the 1990s the Gang de Roubaix used the Škorpion in a series of attacks in France. In 2017 police in Sweden estimated that about 50 deactivated weapons from Slovakia were in circulation among criminals in Sweden; the Škorpion is a select-fire, straight blowback-operated weapon that fires from the closed bolt position. The cartridge used produces a low recoil impulse and this enables simple unlocked blowback operation to be employed; when fired, gas pressure drives the case back in the chamber against the resistance provided by the weight of the bolt and its two recoil springs. The bolt travels back, extracting the empty case, ejected straight upwards through a port in the receiver housing top cover; the Škorpion’s compact dimensions were achieved by using a telescopic bolt assembly that wraps around a considerable portion of the barrel.

The weapon features a spring-loaded casing extractor, installed inside the bolt head and a fixed, double ejector, a protrusion in the weapon’s frame. As the bolt is light, an inertial rate reducer device housed inside the wooden pistol grip lowers the weapon's rate of fire from 1,000 rounds/min to a more manageable 850 rounds/min; the rate reducer operates as follows: when the bolt reaches the end of its rearward stroke it strikes and is caught by a spring-powered hook mounted on the back plate. At the same time it drives a spring-loaded plunger down into the pistol grip; the plunger is accelerated and passes through a heavy weight, left behind because of its inertia. The plunger, having compressed its spring, is driven up again and meets the descending inertia buffer; this slows down the rising plunger which, when it reaches the top of its travel, rotates the hook, releasing the bolt, driven forward by the compressed recoil springs. The weapon is hammer-fired and has a trigger mechanism with a fire mode selector, whose lever has three settings: "0", weapon is safe.

The "safe" setting disables the bolt in the forward position. The Škorpion uses the 7.65×17mmSR Browning Short pistol cartridge, the standard service cartridge of the Czechoslovak security forces. It uses two types of double-column curved box magazines: a short 10-round magazine or a 20-round capacity magazine; the bolt remains locked open after the last cartridge from the magazine has been fired and can be snapped back forward by pulling the cocking handle knob to the rear. The Škorpion is equipped with open-type iron sights and a folding metal wire shoulder stock, which folds up and over the receiver and is locked on the front sight’s protection capture; the Škorpion, together with a short magazine, is carried like a traditional pistol: in a leather holster, the two spare long magazines are carried in a separate pouch. The weapon comes with front sight adjustment tool, oil bottle and lanyard. In the 1960s, three other variants of the vz. 61 were developed in Czechoslovakia: the vz. 64, the vz.

65—designed for use with the 9×18mm Makarov cartridge, the vz. 68. In the 1990s Česká zbrojovka offered the following submachine guns: the vz. 61 E, the vz. 82 and the vz. 83. A semi-automatic only variant known as the CZ-91S was developed for the civilian market, available in the aforementioned calibers; the vz. 82, vz. 83 and CZ-91S pistols chambered in 9 mm use straight box magazines. M84 "ŠKORPION", licensed and produced by Yugoslavia between 1984 and 1992 Serbia. Afghanistan Algeria Angola Czech Republic Egypt Georgia Mostly used by Police forces. Indonesia: Komando Pasukan Katak tactical diver group and Komando Pasukan Khusus special forces group. Jordan Iraq Lebanon Liberia: received Serbian M84s in 2002 Libya

Mark Konkol

Mark Konkol is a Pulitzer Prize-winning writer from Chicago. Konkol was raised in Chicago's south suburbs, he graduated in 1991 from Thornwood High School in Illinois. He attended Culver–Stockton College for two years, where he was a starting lineman for the Wildcats football team, he transferred to Western Illinois University, where he graduated in 1995 with bachelor's degrees in communication and journalism. While at Western Illinois, he was a reporter and news editor at the Western Courier, the university's student newspaper. During the spring before his graduation, Konkol was hired by the Macomb Journal newspaper in Macomb, Illinois where he covered county government and high school sports. Konkol wrote for Star Newspapers, he covered Chicago City Hall for the Daily Southtown newspaper and wrote a column for the Chicago Sun-Times' Red Streak edition. He joined the Sun-Times' news staff in 2004 and has covered transportation, Cook County courts and government and Chicago neighborhoods. In 2011, he became the paper's Writer at Large.

Among other things, Konkol wrote columns and an occasional blog for the Chicago Sun-Times called "Konkol's Korner." In September 2012, Konkol resigned from the Sun-Times to join DNAinfo.com as the start-up local news website's Writer at Large. In early 2017, he left DNAinfo after four years to pursue other interests, such as television production. DNAinfo folded in November 2017. In 2014, Konkol narrated CNN's Chicagoland documentary series. On April 18, 2011, crime reporter Frank Main and photographer John J. Kim won the Pulitzer Prize for Local Reporting for “their immersive documentation of violence in Chicago neighborhoods, probing the lives of victims and detectives as a widespread code of silence impedes solutions.” Konkol lives in Chicago's Pullman neighborhood on the city's South Side

Eastbridge Hospital of St Thomas the Martyr, Canterbury

The Hospital of St Thomas the Martyr of Eastbridge was founded in the 12th century in Canterbury, England, to provide overnight accommodation for poor pilgrims to the shrine of St Thomas Becket. It is now one of the ten almshouses still providing accommodation for elderly citizens of Canterbury and is a grade I listed building; the hospital is situated near the Westgate, in Canterbury. It was established sometime after the death of Thomas Becket as early as 1176, when Canterbury Cathedral became a site of pilgrimage; the earliest name recorded as founder is that of Edward FitzOdbold c. 1190, with further endowments by Archbishop Hubert Walter about 1203. For many years, no special statutes were enacted, nor were any rules laid down for the treatment of pilgrims. In the fourteenth century the Hospital was reformed by Archbishop John de Stratford, during the reign of Edward III, he ruled that every pilgrim in health could rest in the lodgment for one night at the cost of four pence, that weak and infirm applicants were to be preferred to those with better health, that women "upwards of forty" should attend to the bedding and administer medicines to the sick.

He appointed a Master in priest's orders, under whose guidance a secular chaplain served. Further lands and revenues from parishes were given by Stratford and by Archbishop Simon Sudbury; this institution survived the Dissolution of the Monasteries and other religious houses during the reigns of Henry VIII and Edward VI, although the pilgrimage to St Thomas of Canterbury did not survive this period. In 1569 Archbishop Matthew Parker issued new ordinances governing the Hospital and its Master which specified the maintenance of twelve beds for the'wayfaring poor' and established a school in the chapel for twenty boys; this arrangement was confirmed by Archbishop John Whitgift by Act of Parliament in 1584. The school survived until 1879; the chapel was little used until its restoration by the Master in 1927. Further restoration work has taken place during the twentieth century. Much of this work was financed by sale of some of the Hospital's lands at Blean at the foundation of the University of Kent in the 1960s: since the fourteenth century the Master of Eastbridge has been the Lord of the Manor of Blean.

The Master is now the rector of several of the amalgamated city parishes. Since 2003, the Hospital has been cared for by an Anglican Franciscan community, the Society of Saint Francis. A list of the Masters of the Eastbridge Hospital up to the end of the eighteenth century is given by Edward Hasted; the hospital of King's Bridge from Edward Hasted, The History and Topographical Survey of the County of Kent: Volume 12, pp. 115–135. Hospitals in and around Canterbury from A History of the County of Kent: Volume 2, pp. 209–216. The mirror of literature and instruction, Vol. 10, Issue 268 Official website

Bodmin Moor

Bodmin Moor is a granite moorland in northeastern Cornwall, England. It is 208 square kilometres in size, dates from the Carboniferous period of geological history, it includes Brown Willy, the highest point in Cornwall, Rough Tor, a lower peak. Many of Cornwall's rivers have their sources here, it has been inhabited since at least the Neolithic era, when primitive farmers started clearing trees and farming the land. They left their megalithic monuments, hut circles and cairns, the Bronze Age culture that followed left further cairns, more stone circles and stone rows. By medieval and modern times, nearly all the forest was gone and livestock rearing predominated; the name Bodmin Moor is recent. An early mention is in the Royal Cornwall Gazette of 28 November 1812; the upland area was known as Fowey Moor after the River Fowey, which rises within it. Bodmin Moor is one of five granite plutons in Cornwall. Dramatic granite tors rise from the rolling moorland: the best known are Brown Willy, the highest point in Cornwall at 417 m, Rough Tor at 400 m.

To the south-east Kilmar Tor and Caradon Hill are the most prominent hills. Considerable areas of the moor are poorly form marshes; the rest of the moor is rough pasture or overgrown with heather and other low vegetation. The moor contains about 500 holdings with around 10,000 beef cows, 55,000 breeding ewes and 1,000 horses and ponies. Most of the moor is a Site of Special Scientific Interest, Bodmin Moor and has been designated an Area of Outstanding Natural Beauty, as part of Cornwall AONB; the moor has been identified by BirdLife International as an Important Bird Area because it supports about 260 breeding pairs of European stonechats as well as a wintering population of 10,000 Eurasian golden plovers. The moor has been recognised as a separate natural region and designated as national character area 153 by Natural England. Bodmin Moor is the source of several of Cornwall's rivers: they are mentioned here anti-clockwise from the south; the River Fowey flows through Lostwithiel and into the Fowey estuary.

The River Tiddy flows southeast to its confluence with the River Lynher. The River Inny flows southeast to its confluence with the River Tamar; the River Camel rises on Hendraburnick Down and flows for 40 km before joining the sea at Padstow. The River Camel and its tributary the De Lank River are an important habitat for the otter, both have been proposed as Special Areas of Conservation The De Lank River rises near Roughtor and flows along an irregular course before joining the Camel south of Wenford; the River Warleggan flows south to join the Fowey. On the southern slopes of the moor lies Dozmary Pool, it is glacial in origin. In the 20th century three reservoirs have been constructed on the moor. Various species of waterfowl are resident around these waters; the parishes on the moor are as follows: 10,000 years ago, in the Mesolithic period, hunter-gatherers wandered the area when it was wooded. There are several documented cases of flint scatters being discovered by archaeologists, indicating that these hunter-gatherers practised flint knapping in the region.

During the Neolithic era, from about 4,500 to 2,300 BC, people began clearing trees and farming the land. It was in this era that the production of various megalithic monuments began, predominantly long cairns and stone circles, it was likely that the forming tors were viewed in a similar manner to the manmade ceremonial sites. In the following Bronze Age, the creation of monuments increased with the production of over 300 further cairns, more stone circles and stone rows. More than 200 Bronze Age settlements with enclosures and field patterns have been recorded, and many prehistoric stone barrows and circles lie scattered across the moor. In a programme shown in 2007 Channel 4's Time Team investigated a 500-metre cairn and the site of a Bronze Age village on the slopes of Rough Tor. King Arthur's Hall, thought to be a late Neolithic or early Bronze Age ceremonial site, can be found to the east of St Breward on the moor. Where practicable, areas of the moor were used for pasture by herdsmen from the parishes surrounding the moor.

Granite boulders were taken from the moor and used for stone posts and to a certain extent for building. Granite quarrying only became reasonably productive; the moor gave its name to one of the medieval districts called stannaries which administered tin mining: the boundaries of these were never defined precisely. Until the establishment of a turnpike road through the moor in the 1770s the size of the moorland area made travel within Cornwall difficult, its Cornish name, Goen Bren, is first recorded in the 12th century. English Heritage monographs "Bodmin Moor: An Archaeological Survey" Volume 1 and Volume 2 covering the post-medieval and modern landscape are publicly available through the Archaeology Data Service. Jamaica Inn is a traditional inn on the Moor. Built as a coaching inn in 1750 and having an association with smuggling

NME4

Non-metastatic cells 4, protein expressed in known as NME4, is a protein which in humans is encoded by the NME4 gene. The nucleoside diphosphate kinases are ubiquitous enzymes that catalyze transfer of gamma-phosphates, via a phosphohistidine intermediate, between nucleoside and dioxynucleoside tri- and diphosphates; the enzymes are products of the nm23 gene family, which includes NME4. The first nm23 gene, nm23-H1, was isolated based on its reduced expression in a metastatic murine melanoma cell line and was proposed to be a metastasis suppressing gene; the human equivalent was obtained by cDNA library screening using the murine gene as a probe and found to be homologous to the Drosophila awd gene. A second human gene, nm23-H2, encoding a protein 88% identical to nm23-H1, was subsequently isolated. Both genes were localized on 17q21.3 and their gene products were identified as the A and B subunits of NDP kinases. In mammals, functional NDP kinases are heterohexamers of the A and B monomers, which can combine at variable ratios to form different types of hybrids.

These enzymes are expressed in tumors as compared with normal tissues. In some cell lines and in certain solid tumors, decreased expression of NME1 is associated with increased metastatic potential. A third human gene, DR-nm23, was identified and found to share high sequence similarity with the NME1 and NME2 genes, it is expressed in blast crisis transition of chronic myeloid leukemia. When overexpressed by transfection, NME3 suppressed granulocyte differentiation and induced apoptosis of myeloid precursor cells. Model organisms have been used in the study of NME4 function. A conditional knockout mouse line called Nme4tm1aWtsi was generated at the Wellcome Trust Sanger Institute. Male and female animals underwent a standardized phenotypic screen to determine the effects of deletion. Additional screens performed: - In-depth immunological phenotyping