title: Lindisfarne content: the 9th century "Historia Brittonum". Following up on a suggestion by Richard Coates, Andrew Breeze proposes that the name ultimately derives from Latin "Medicata [Insula]" (), owing perhaps to the island's reputation for medicinal herbs. Both the" Parker Chronicle "and" Peterborough Chronicle" annals of AD 793 record the Old English name, "Lindisfarena". The soubriquet "Holy Island" was in use by the 11th century when it appears in Latin as "Insula Sacra". The reference was to Saints Aidan and Cuthbert. The name Lindisfarne has an uncertain origin. The first part, "Lindis-", may refer to people from the Kingdom of Lindsey in


title: Lindisfarne content: modern Lincolnshire, referring to either regular visitors or settlers. Alternatively the name may be Celtic in origin, with the element "Lindis-" meaning "stream or pool". It is not known if this is a reference to the nearby River Low or a small lake on the island. The second element, "-farne", probably comes from "farran", meaning "land", but may come from "faran", meaning "traveller". There is also a supposition that the nearby Farne Islands are fern like in shape and the name may have come from there. The island measures from east to west and from north to south, and comprises


title: Lindisfarne content: approximately at high tide. The nearest point of the island is about from the mainland of England. The island of Lindisfarne is located along the northeast coast of England, close to the border with Scotland. It is accessible, most times, at low tide by crossing sand and mudflats which are covered with water at high tides. These sand and mud flats carry an ancient pilgrims' path, and in more recent times, a modern causeway. Lindisfarne is surrounded by the Lindisfarne National Nature Reserve, which protects the island's sand dunes and the adjacent intertidal habitats. , the island had a population


title: Lindisfarne content: of 180. Warning signs urge visitors walking to the island to keep to the marked path, to check tide times and weather carefully, and to seek local advice if in doubt. For drivers, tide tables are prominently displayed at both ends of the causeway and also where the Holy Island road leaves the A1 Great North Road at Beal. The causeway is generally open from about three hours after high tide until two hours before the next high tide, but the period of closure may be extended during stormy weather. Tide tables giving the safe crossing periods are published by


title: Lindisfarne content: Northumberland County council. Despite these warnings, about one vehicle each month is stranded on the causeway, requiring rescue by HM Coastguard, Seahouses RNLI lifeboat, or RAF helicopter. A sea rescue costs approximately £1,900 (quoted in 2009, ), while an air rescue costs more than £4,000 (also quoted in 2009, ). Local people have opposed a causeway barrier primarily on convenience grounds. Trinity House operates two lighthouses to guide vessels entering Holy Island Harbour, named Guile Point East and Heugh Hill. The former is one of a pair of stone obelisks standing on a small tidal island on the other side


title: Lindisfarne content: of the channel. The obelisks are leading marks which, when aligned, indicate the safe channel over the bar. When Heugh Hill bears 310° (in line with the church belfry) the bar is cleared and there is a clear run into the harbour. Since the early 1990s, a sector light has been fixed to it about one-third of the way up Guile Point East. The latter is a metal framework tower with a black triangular day mark, situated on a ridge on the south edge of Lindisfarne. Before November 1995 both were owned/operated by Newcastle-upon-Tyne Trinity House. Nearby is a former


title: Lindisfarne content: coastguard station (recently refurbished and opened to the public as a viewing platform). An adjacent ruin is known as the Lantern Chapel; its origin is unknown, but the name may indicate an earlier navigation light on this site. Not a lighthouse but simply a daymark for maritime navigation, a white brick pyramid, 35 feet high and built in 1810, stands at Emmanuel Head, the north-eastern point of Lindisfarne. It is said to be Britain's earliest purpose-built daymark. The northeast coast of England was largely unsettled by Roman civilians apart from the Tyne valley and Hadrian's Wall. The area had been


title: Lindisfarne content: little affected during the centuries of nominal Roman occupation. The countryside had been subject to raids from both Scots and Picts and was "not one to attract early Germanic settlement". King Ida (reigned from 547) started the sea-borne settlement of the coast, establishing an "urbs regia" at Bamburgh across the bay from Lindisfarne. The conquest was not straightforward, however. The "Historia Brittonum" recounts how, in the 6th century, Urien, prince of Rheged, with a coalition of North British kingdoms, besieged Angles led by Theodric of Bernicia at the island for three days and nights, until internal power struggles led to


title: Lindisfarne content: the Britons' defeat. The monastery of Lindisfarne was founded by Irish monk Saint Aidan, who had been sent from Iona off the west coast of Scotland to Northumbria at the request of King Oswald. The priory was founded before the end of 634 and Aidan remained there until his death in 651. The priory remained the only seat of a bishopric in Northumbria for nearly thirty years. Finian (bishop 651–661) built a timber church "suitable for a bishop's seat". St Bede, however, was critical of the fact that the church was not built of stone but only of hewn oak


title: Lindisfarne content: thatched with reeds. A later bishop, Eadbert removed the thatch and covered both walls and roof in lead. An abbot, who could be the bishop, was elected by the brethren and led the community. Bede comments on this: Lindisfarne became the base for Christian evangelism in the North of England and also sent a successful mission to Mercia. Monks from the Irish community of Iona settled on the island. Northumbria's patron saint, Saint Cuthbert, was a monk and later abbot of the monastery, and his miracles and life are recorded by the Venerable Bede. Cuthbert later became Bishop of Lindisfarne.


title: Lindisfarne content: An anonymous life of Cuthbert written at Lindisfarne is the oldest extant piece of English historical writing. From its reference to "Aldfrith, who now reigns peacefully" it must date to between 685 and 704. Cuthbert was buried here, his remains later translated to Durham Cathedral (along with the relics of Saint Eadfrith of Lindisfarne). Eadberht of Lindisfarne, the next bishop (and saint) was buried in the place from which Cuthbert's body was exhumed earlier the same year when the priory was abandoned in the late 9th century. Cuthbert's body was carried with the monks, eventually settling in Chester-le-Street before a


title: Lindisfarne content: final move to Durham. The saint's shrine was the major pilgrimage centre for much of the region until its despoliation by Henry VIII's commissioners in 1539 or 1540. The grave was preserved, however, and when opened in 1827 yielded a number of remarkable artefacts dating back to Lindisfarne. The inner (of three) coffins was of incised wood, the only decorated wood to survive from the period. It shows Jesus surrounded by the Four Evangelists. Within the coffin was a pectoral cross across made of gold and mounted with garnets and intricate tracery. There was a comb made of elephant ivory,


title: Lindisfarne content: a rare and expensive item in Northern England. Also inside was an embossed silver covered travelling altar. All were contemporary with the original burial on the island. When the body was placed in the shrine in 1104 other items were removed: a paten, scissors and a chalice of gold and onyx. Most remarkable of all was a gospel (known as the St Cuthbert Gospel or Stonyhurst Gospel from its association with the college). The manuscript is in an early, probably original, binding beautifully decorated with deeply embossed leather. Following Finian's death, Colman became Bishop of Lindisfarne. Up to this point


title: Lindisfarne content: the Northumbrian (and latterly Mercian) churches had looked to Lindisfarne as the mother church. There were significant liturgical and theological differences with the fledgling Roman party based at Canterbury. According to Stenton: "There is no trace of any intercourse between these bishops [the Mercians] and the see of Canterbury". The Synod of Whitby in 663 changed this. Allegiance switched southwards to Canterbury and thence to Rome. Colman departed his see for Iona and Lindisfarne ceased to be of such major importance. In 735 the northern ecclesiastical province of England was established with the archbishopric at York. There were only three


title: Lindisfarne content: bishops under York: Hexham, Lindisfarne and Whithorn whereas Canterbury had the twelve envisaged by St Augustine. The Diocese of York encompassed roughly the counties of Yorkshire and Lancashire. Hexham covered County Durham and the southern part of Northumberland up to the River Coquet and eastwards into the Pennines. Whithorn covered most of Dumfries and Galloway region west of Dumfries itself. The remainder, Cumbria, northern Northumbria, Lothian and much of the Kingdom of Strathclyde formed the diocese of Lindisfarne. In 737 Saint Ceolwulf of Northumbria abdicated as King of Northumbria and entered the Prior at Lindisfarne. He died in 764 and


title: Lindisfarne content: was buried alongside Cuthbert. In 830 his body was moved to Norham-upon-Tweed and later his head was translated to Durham Cathedral. At some point in the early 8th century, the famous illuminated manuscript known as the Lindisfarne Gospels, an illustrated Latin copy of the Gospels of Matthew, Mark, Luke and John, was made probably at Lindisfarne and the artist was possibly Eadfrith, who later became Bishop of Lindisfarne. Sometime in the second half of the 10th century a monk named Aldred added an Anglo-Saxon (Old English) gloss to the Latin text, producing the earliest surviving Old English copies of the


title: Lindisfarne content: Gospels. Aldred attributed the original to Eadfrith (bishop 698–721). The Gospels were written with a good hand, but it is the illustrations done in an insular style containing a fusion of Celtic, Germanic and Roman elements that are truly outstanding. According to Aldred, Eadfrith's successor Æthelwald was responsible for pressing and binding it and then it was covered with a fine metal case made by a hermit called Billfrith. The Lindisfarne Gospels now reside in the British Library in London, somewhat to the annoyance of some Northumbrians. In 1971 professor Suzanne Kaufman of Rockford, Illinois presented a facsimile copy of


title: Lindisfarne content: the Gospels to the clergy of the island. In 793, a Viking raid on Lindisfarne caused much consternation throughout the Christian west and is now often taken as the beginning of the Viking Age. The D and E versions of the "Anglo-Saxon Chronicle" record: Her wæron reðe forebecna cumene ofer Norðhymbra land, ⁊ þæt folc earmlic bregdon, þæt wæron ormete þodenas ⁊ ligrescas, ⁊ fyrenne dracan wæron gesewene on þam lifte fleogende. Þam tacnum sona fyligde mycel hunger, ⁊ litel æfter þam, þæs ilcan geares on .vi. Idus Ianuarii, earmlice hæþenra manna hergunc adilegode Godes cyrican in Lindisfarnaee þurh hreaflac


title: Lindisfarne content: ⁊ mansliht. In this year fierce, foreboding omens came over the land of the Northumbrians, and the wretched people shook; there were excessive whirlwinds, lightning, and fiery dragons were seen flying in the sky. These signs were followed by great famine, and a little after those, that same year on 6th ides of January, the ravaging of wretched heathen men destroyed God's church at Lindisfarne. The generally accepted date for the Viking raid on Lindisfarne is in fact 8 June; Michael Swanton writes: ""vi id Ianr", presumably [is] an error for "vi id Iun" (8 June) which is the date


title: Lindisfarne content: given by the "Annals of Lindisfarne" (p. 505), when better sailing weather would favour coastal raids." Alcuin, a Northumbrian scholar in Charlemagne's court at the time, wrote: Never before has such terror appeared in Britain as we have now suffered from a pagan race ... The heathens poured out the blood of saints around the altar, and trampled on the bodies of saints in the temple of God, like dung in the streets. The English seemed to have turned their back on the sea as they became more settled. Many monasteries were established on islands, peninsulas, river mouths and cliffs.


title: Lindisfarne content: Isolated communities were less susceptible to interference and the politics of the heartland. The amazement of the English at the raids from the sea must have been matched by the amazement of the raiders at such (to them) vulnerable, wealthy and unarmed settlements. These preliminary raids, unsettling as they were, were not followed up. The main body of the raiders passed north around Scotland. The 9th-century invasions came not from Norway, but from the Danes from around the entrance to the Baltic. The first Danish raids into England were in the Isle of Sheppey, Kent during 835 and from there


title: Lindisfarne content: their influence spread north. During this period religious art continued to flourish on Lindisfarne, and the "Liber Vitae" of Durham began in the priory. By 866 the Danes were in York and in 873 the army was moving into Northumberland. With the collapse of the Northumbrian kingdom the monks of Lindisfarne fled the island in 875 taking with them St Cuthbert's bones (which are now buried at the cathedral in Durham). Prior to the 9th century Lindisfarne Priory had, in common with other such establishments, held large tracts of land which were managed directly or leased to farmers with a


title: Lindisfarne content: life interest only. Following the Danish occupation land was increasingly owned by individuals and could be bought, sold and inherited. Following the Battle of Corbridge in 914 Ragnald seized the land giving some to his followers Scula and Onlafbal. The priory was re-established in Norman times in 1093 as a Benedictine house and continued until its suppression in 1536 under Henry VIII. The standing remains date from this later priory, while the site of the original priory is now occupied by the parish church. The site is a grade I listed building number 1042304. The earliest parts of the area


title: Lindisfarne content: are a scheduled ancient monument number 1011650. In 1462, during the Wars of the Roses, Margaret of Anjou made an abortive attempt to seize the Northumbrian castles. Following a storm at sea 400 troops had to seek shelter on Holy Island, where they surrendered to the Yorkists. An early scholarly description of the priory was compiled by Dr Henry George Charles Clarke (presumed son of Admiral Sir Erasmus Gower) in 1838 during his term as president of the Berwickshire Naturalists' Club. . Dr Clarke surmised that this Norman priory was unique in that the centre aisle had a vault of


title: Lindisfarne content: stone. Of the six arches, Dr Clarke stated "as if the architect had not previously calculated the space to be occupied by his arcade. The effect here has been to produce a horse-shoe instead of a semicircular arch, from its being of the same height, but lesser span, than the others. This arch is very rare, even in Norman buildings". Lindisfarne Castle was built in 1550, around the time that Lindisfarne Priory went out of use, and stones from the priory were used as building material. It is very small by the usual standards, and was more of a fort.


title: Lindisfarne content: The castle sits on the highest point of the island, a whinstone hill called Beblowe. After Henry VIII suppressed the priory, his troops used the remains as a naval store. In 1542 Henry VIII ordered the Earl of Rutland to fortify the site against possible Scottish invasion. By December 1547, Ralph Cleisbye, Captain of the fort, had guns including a wheel-mounted demi-culverin, two brass sakers, a falcon, and another fixed demi-culverin. However, Beblowe Crag itself was not fortified until 1549 and Sir Richard Lee saw only a decayed platform and turf rampart there in 1565. Elizabeth I then had work


title: Lindisfarne content: carried out on the fort, strengthening it and providing gun platforms for the new developments in artillery technology. When James VI and I came to power in England, he combined the Scottish and English thrones, and the need for the castle declined. At that time the castle was still garrisoned from Berwick and protected the small Lindisfarne Harbour. During the Jacobite Rising of 1715, Lancelot Errington, one of a number of locals who supported the Jacobite cause, visited the castle. Some sources say that he asked the Master Gunner, who also served as the unit's barber, for a shave. Once


title: Lindisfarne content: Errington was inside, it became clear that most of the garrison were away; later that day he returned with his nephew Mark Errington, claiming that he had lost the key to his watch. They were allowed in, overpowered the three soldiers present, and claimed the castle as a landing site for the Jacobite group led by Thomas Forster, Member of Parliament for the county of Northumberland. Reinforcements did not arrive to support the Erringtons, so when a detachment of 100 men arrived from Berwick to retake the castle they were only able to hold out for one day. Fleeing, they


title: Lindisfarne content: were captured at the tollbooth at Berwick and imprisoned, but were later able to tunnel out of their gaol and escape. A Dundee firm built lime kilns on Lindisfarne in the 1860s, and lime was burnt on the island until at least the end of the 19th century. The kilns are among the most complex in Northumberland. Horses carried limestone, along the Holy Island Waggonway, from a quarry on the north side of the island to the lime kilns, where it was burned with coal transported from Dundee on the east coast of Scotland. There are still some traces of


title: Lindisfarne content: the jetties by which the coal was imported and the lime exported close by at the foot of the crags. The remains of the waggon way between the quarries and the kilns makes for a pleasant and easy walk. At its peak over 100 men were employed. Crinoid columnals extracted from the quarried stone and threaded into necklaces or rosaries became known as St Cuthbert's beads. Workings on the lime kilns stopped by the start of the 20th century. The lime kilns on Lindisfarne are among the few being actively preserved in Northumberland. Holy Island Golf Club was founded in


title: Lindisfarne content: 1907 but later closed in the 1960s. The island is within an "Area of Outstanding Natural Beauty" on the Northumberland Coast. The ruined monastery is in the care of English Heritage, which also runs a museum/visitor centre nearby. The neighbouring parish church (see below) is still in use. Lindisfarne also has the small Lindisfarne Castle, based on a Tudor fort, which was refurbished in the Arts and Crafts style by Sir Edwin Lutyens for the editor of Country Life, Edward Hudson. Lutyens also designed the island's Celtic-cross war-memorial on the Heugh. Lutyens' upturned herring busses near the foreshore provided the


title: Lindisfarne content: inspiration for Spanish architect Enric Miralles' Scottish Parliament Building in Edinburgh. One of the most celebrated gardeners of modern times, Gertrude Jekyll (1843–1932), laid out a tiny garden just north of the castle in 1911. The castle, garden and nearby lime kilns are in the care of the National Trust and open to visitors. Turner, Thomas Girtin and Charles Rennie Mackintosh all painted on Holy Island. Holy Island was considered part of the Islandshire unit along with several mainland parishes. This came under the jurisdiction of the County Palatine of Durham until the Counties (Detached Parts) Act 1844. Lindisfarne was


title: Lindisfarne content: mainly a fishing community for many years, with farming and the production of lime also of some importance. The Holy Island of Lindisfarne is well known for mead. In the mediaeval days when monks inhabited the island, it was thought that if the soul was in God's keeping, the body must be fortified with Lindisfarne mead. The monks have long vanished, and the mead's recipe remains a secret of the family which still produces it; Lindisfarne Mead is produced at St Aidan's Winery, and sold throughout the UK and elsewhere. The isle of Lindisfarne was featured on the television programme


title: Lindisfarne content: "Seven Natural Wonders" as one of the wonders of the North. The Lindisfarne Gospels have also featured on television among the top few Treasures of Britain. It also features in an ITV Tyne Tees programme "Diary of an Island" which started on 19 April 2007 and on a DVD of the same name. When the abbey was rebuilt by the Normans, the site was moved. The site of the original priory church was redeveloped in stone as the parish church. As such it is now the oldest building on the island still with a roof on. Remains of the Saxon


title: Lindisfarne content: church exist as the chancel wall and arch. A Norman apse (subsequently replaced in the 13th century) led eastwards from the chancel. The nave was extended in the 12th century with a northern arcade, and in the following century with a southern arcade. After the Reformation the church slipped into disrepair until the restoration of 1860. The church is built of coloured sandstone which has had the Victorian plaster removed from it. The north aisle is known as the "fishermen's aisle" and houses the altar of St Peter. The south aisle used to hold the altar of St Margaret of


title: Lindisfarne content: Scotland, but now houses the organ. The church is a Grade I listed building number 1042304, listed as part of the whole priory. The church forms most of the earliest part of the site and is a scheduled ancient monument number 1011650. For long years David Adam was rector of Holy Island and ministered to thousands of pilgrims and other visitors. In response to the perceived lack of affordable housing on the isle of Lindisfarne, in 1996 a group of islanders established a charitable foundation known as the Holy Island of Lindisfarne Community Development Trust. They built a visitor centre


title: Lindisfarne content: on the island using the profits from sales. In addition, eleven community houses were built and are rented out to community members who want to continue to live on the island. The trust is also responsible for management of the inner harbour. The Holy Island Partnership was formed in 2009 by members of the community as well as organisations and groups operating on the island. Tourism grew steadily throughout the 20th century, and the isle of Lindisfarne is now a popular destination for visitors. Those tourists staying on the island while it is cut off by the tide experience the


title: Lindisfarne content: island in a much quieter state, as most day trippers leave before the tide rises. At low tide it is possible to walk across the sands following an ancient route known as the Pilgrims' Way, but see the note above. This route is marked with posts and has refuge boxes for stranded walkers, just as the road has a refuge box for those who have left their crossing too late. The isle of Lindisfarne is surrounded by the 8,750-acre Lindisfarne National Nature Reserve which attracts bird-watchers to the tidal island. The island's prominent position and varied habitat make it particularly


title: Lindisfarne content: attractive to tired migrants, and 330 bird species had been recorded on the island. Lindisfarne The Holy Island of Lindisfarne, also known simply as Holy Island, is a tidal island off the northeast coast of England, which constitutes the civil parish of Holy Island in Northumberland. Holy Island has a recorded history from the 6th century AD; it was an important centre of Celtic Christianity under Saints Aidan of Lindisfarne, Cuthbert, Eadfrith of Lindisfarne and Eadberht of Lindisfarne. After the Viking invasions and the Norman conquest of England, a priory was reestablished. A small castle was built on the island


title: Lexeme content: a present non-third-person singular form "run" (which also functions as the past participle and non-finite form), a past form "ran", and a present participle "running". (It does not include "runner, runners, runnable," etc.) The use of the forms of a lexeme is governed by rules of grammar; in the case of English verbs such as RUN, these include subject-verb agreement and compound tense rules, which determine which form of a verb can be used in a given sentence. A lexicon consists of lexemes. A lexeme consists of morphemes. In many formal theories of language, lexemes have subcategorization frames to account


title: "L'Hôpital's rule" content: rule because it is stricter in its definition, requiring both differentiability and that "c" be a real number. Since many common functions have continuous derivatives (e.g. polynomials, sine and cosine, exponential functions), it is a special case worthy of attention. Suppose that and are continuously differentiable at a real number , that formula_62, and that formula_63. Then This follows from the difference-quotient definition of the derivative. The last equality follows from the continuity of the derivatives at . The limit in the conclusion is not indeterminate because formula_65. The proof of a more general version of L'Hôpital's rule is given


title: "L'Hôpital's rule" content: superior and limit inferior are necessary since the existence of the limit of has not yet been established. It is also the case that and In case 1, the squeeze theorem establishes that formula_94 exists and is equal to "L". In the case 2, and the squeeze theorem again asserts that formula_95, and so the limit formula_94 exists and is equal to "L". This is the result that was to be proven. In case 2 the assumption that "f"("x") diverges to infinity was not used within the proof. This means that if |"g"("x")| diverges to infinity as "x" approaches "c"


title: "Labrador duck" content: surf scoter and the common goldeneye (and even the American oystercatcher), a fact that has led to difficulties in interpreting old records of these species. Both names refer to the male's striking white/black piebald coloration. Yet another common name was sand shoal duck, referring to its habit of feeding in shallow water. The closest evolutionary relatives of the Labrador duck are apparently the scoters ("Melanitta"). A mitogenomic study of the placement of the Labrador duck found the species to be closely related to the Steller's eider as shown below. The female plumage was gray. Although weakly patterned, the pattern was


title: "Leyden jar" content: van Musschenbroek of Leiden (Leyden) in 1745–1746. The invention was named after the city. The Leyden jar was used to conduct many early experiments in electricity, and its discovery was of fundamental importance in the study of electrostatics. The Leyden jar was the first means of accumulating and preserving electric charge in large quantities that could be discharged at the experimenter's will, thus overcoming a significant limit to early research into electrical conduction. Leyden jars are still used in education to demonstrate the principles of electrostatics. The Ancient Greeks already knew that pieces of amber could attract lightweight particles after


title: Metaphilosophy content: form of metaphilosophy, as well as meta-epistemology, the study of epistemology. Many sub-disciplines of philosophy have their own branch of 'metaphilosophy', examples being meta-aesthetics, meta-epistemology, meta-ethics, meta-ontology, and so forth. However, some topics within 'metaphilosophy' cut across the various subdivisions of philosophy to consider fundamentals important to all its sub-disciplines. Some of these are mentioned below. Some philosophers (e.g. existentialists, pragmatists) think philosophy is ultimately a practical discipline that should help us lead meaningful lives by showing us who we are, how we relate to the world around us and what we should do. Others (e.g. analytic philosophers) see philosophy


title: Mandolin content: group of virtuoso players and ensembles such as Alberto Valderrama, Jesus Rengel, Ricardo Sandoval, Saul Vera, and Cristobal Soto. The French ruled Vietnam completely by 1884 and set up a system of modern education. The population was exposed to French culture and music, which included the mandolin. The influence of French culture was strong enough to affect Vietnamese music. They began writing lyrics to French pop music in Vietnamese and teaching themselves other western instruments including mandolin, guitar, Hawaiian guitar and banjo. Through the Catholics and later the conservatories, European classical music and instruments were taught, including piano and bowed


title: Microfluidics content: Although droplets are manipulated in confined microfluidic channels, since the control on droplets is not independent, it should not be confused as "digital microfluidics". One common actuation method for digital microfluidics is electrowetting-on-dielectric (EWOD). Many lab-on-a-chip applications have been demonstrated within the digital microfluidics paradigm using electrowetting. However, recently other techniques for droplet manipulation have also been demonstrated using magnetic force, surface acoustic waves, optoelectrowetting, mechanical actuation, etc. Paper-based microfluidic devices fill a growing niche for portable, cheap, and user-friendly medical diagnostic systems. Paper based microfluidics rely on the phenomenon of capillary penetration in porous media. In order to tune


title: Metre content: Metre The metre (British spelling and BIPM spelling) or meter (American spelling) (from the French unit "mètre", from the Greek noun μέτρον, "measure") is the base unit of length in some metric systems, including the International System of Units (SI). The SI unit symbol is m. The metre is defined as the length of the path travelled by light in a vacuum in second. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole – as a result the Earth's circumference is approximately 40,000 km today. In 1799, it was


title: Metre content: redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted. The imperial inch is defined as 0.0254 metres (2.54 centimetres or 25.4 millimetres). One metre is about inches longer than a yard, i.e. about inches. "Metre" is the standard spelling of the metric unit for length in nearly all English-speaking nations except the United States and the Philippines, which use "meter." Other Germanic languages, such as


title: Metre content: German, Dutch, and the Scandinavian languages likewise spell the word "meter." Measuring devices (such as ammeter, speedometer) are spelled "-meter" in all variants of English. The suffix "-meter" has the same Greek origin as the unit of length. The etymological roots of "metre" can be traced to the Greek verb ' (metreo) (to measure, count or compare) and noun ' (metron) (a measure), which were used for physical measurement, for poetic metre and by extension for moderation or avoiding extremism (as in "be measured in your response"). This range of uses is also found in Latin ("metior", "mensura"), French ("mètre",


title: Metre content: "mesure"), English and other languages. The motto "ΜΕΤΡΩ ΧΡΩ" (metro chro) in the seal of the International Bureau of Weights and Measures (BIPM), which was a saying of the Greek statesman and philosopher Pittacus of Mytilene and may be translated as "Use measure!", thus calls for both measurement and moderation. In 1668 the English cleric and philosopher John Wilkins proposed in an essay a decimal-based unit of length, the "universal measure" or "standard" based on a pendulum with a two-second period. The use of the seconds pendulum to define length had been suggested to the Royal Society in 1660 by


title: Metre content: Christopher Wren. Christiaan Huygens had observed that length to be 38 Rijnland inches or 39.26 English inches; that is, 997mm. No official action was taken regarding these suggestions. In 1670 Gabriel Mouton, Bishop of Lyon, also suggested a universal length standard with decimal multiples and divisions, to be based on a one-minute angle of the Earth's meridian arc or (as the Earth's circumference was not easy to measure) on a pendulum with a two-second period. In 1675, the Italian scientist Tito Livio Burattini, in his work ', used the phrase ' ("universal measure"), derived from the Greek ("métron katholikón"), to


title: Metre content: denote the standard unit of length derived from a pendulum. As a result of the French Revolution, the French Academy of Sciences charged a commission with determining a single scale for all measures. On 7 October 1790 that commission advised the adoption of a decimal system, and on 19 March 1791 advised the adoption of the term "mètre" ("measure"), a basic unit of length, which they defined as equal to one ten-millionth of the distance between the North Pole and the Equator. In 1793, the French National Convention adopted the proposal; this use of "metre" in English began at least


title: Metre content: as early as 1797. In 1791, the French Academy of Sciences selected the meridional definition over the pendular definition because the force of gravity varies slightly over the surface of the Earth, which affects the period of a pendulum. To establish a universally accepted foundation for the definition of the metre, more accurate measurements of this meridian were needed. The French Academy of Sciences commissioned an expedition led by Jean Baptiste Joseph Delambre and Pierre Méchain, lasting from 1792 to 1799, which attempted to accurately measure the distance between a belfry in Dunkerque and Montjuïc castle in Barcelona to estimate


title: Metre content: the length of the meridian arc through Dunkerque. This portion of the meridian, assumed to be the same length as the Paris meridian, was to serve as the basis for the length of the half meridian connecting the North Pole with the Equator. The problem with this approach is that the exact shape of the Earth is not a simple mathematical shape, such as a sphere or oblate spheroid, at the level of precision required for defining a standard of length. The irregular and particular shape of the Earth smoothed to sea level is represented by a mathematical model called


title: Metre content: a geoid, which literally means "Earth-shaped". Despite these issues, in 1793 France adopted this definition of the metre as its official unit of length based on provisional results from this expedition. However, it was later determined that the first prototype metre bar was short by about 200 micrometres because of miscalculation of the flattening of the Earth, making the prototype about 0.02% shorter than the original proposed definition of the metre. Regardless, this length became the French standard and was progressively adopted by other countries in Europe. The expedition was fictionalised in Denis Guedj, "Le mètre du Monde". Ken Alder


title: Metre content: wrote factually about the expedition in "The Measure of All Things: the seven year odyssey and hidden error that transformed the world". In 1867 at the second general conference of the International Association of Geodesy held in Berlin, the question of an international standard unit of length was discussed in order to combine the measurements made in different countries to determine the size and shape of the Earth. The conference recommended the adoption of the metre and the creation of an international metre commission, according to the proposal of Johann Jacob Baeyer, Adolphe Hirsch and Carlos Ibáñez e Ibáñez de


title: Metre content: Ibero. In the 1870s and in light of modern precision, a series of international conferences was held to devise new metric standards. The Metre Convention ("Convention du Mètre") of 1875 mandated the establishment of a permanent International Bureau of Weights and Measures (BIPM: ') to be located in Sèvres, France. This new organisation was to construct and preserve a prototype metre bar, distribute national metric prototypes, and maintain comparisons between them and non-metric measurement standards. The organisation created such a bar in 1889 at the first General Conference on Weights and Measures (CGPM: '), establishing the "International Prototype Metre" as


title: Metre content: the distance between two lines on a standard bar composed of an alloy of 90% platinum and 10% iridium, measured at the melting point of ice. The original international prototype of the metre is still kept at the BIPM under the conditions specified in 1889. In 1893, the standard metre was first measured with an interferometer by Albert A. Michelson, the inventor of the device and an advocate of using some particular wavelength of light as a standard of length. By 1925, interferometry was in regular use at the BIPM. However, the International Prototype Metre remained the standard until 1960,


title: Metre content: when the eleventh CGPM defined the metre in the new International System of Units (SI) as equal to 1 650 763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum. To further reduce uncertainty, the 17th CGPM in 1983 replaced the definition of the metre with its current definition, thus fixing the length of the metre in terms of the second and the speed of light: This definition fixed the speed of light in vacuum at exactly metres per second (≈). An intended by-product of the 17th CGPM's definition was that it


title: Metre content: enabled scientists to compare lasers accurately using frequency, resulting in wavelengths with one-fifth the uncertainty involved in the direct comparison of wavelengths, because interferometer errors were eliminated. To further facilitate reproducibility from lab to lab, the 17th CGPM also made the iodine-stabilised helium–neon laser "a recommended radiation" for realising the metre. For the purpose of delineating the metre, the BIPM currently considers the HeNe laser wavelength, , to be with an estimated relative standard uncertainty ("U") of . This uncertainty is currently one limiting factor in laboratory realisations of the metre, and it is several orders of magnitude poorer than


title: Metre content: that of the second, based upon the caesium fountain atomic clock (). Consequently, a realisation of the metre is usually delineated (not defined) today in labs as wavelengths of helium-neon laser light in a vacuum, the error stated being only that of frequency determination. This bracket notation expressing the error is explained in the article on measurement uncertainty. Practical realisation of the metre is subject to uncertainties in characterising the medium, to various uncertainties of interferometry, and to uncertainties in measuring the frequency of the source. A commonly used medium is air, and the National Institute of Standards and Technology


title: Metre content: (NIST) has set up an online calculator to convert wavelengths in vacuum to wavelengths in air. As described by NIST, in air, the uncertainties in characterising the medium are dominated by errors in measuring temperature and pressure. Errors in the theoretical formulas used are secondary. By implementing a refractive index correction such as this, an approximate realisation of the metre can be implemented in air, for example, using the formulation of the metre as wavelengths of helium–neon laser light in vacuum, and converting the wavelengths in a vacuum to wavelengths in air. Air is only one possible medium to use


title: Metre content: in a realisation of the metre, and any partial vacuum can be used, or some inert atmosphere like helium gas, provided the appropriate corrections for refractive index are implemented. The metre is "defined" as the path length travelled by light in a given time and practical laboratory length measurements in metres are determined by counting the number of wavelengths of laser light of one of the standard types that fit into the length, and converting the selected unit of wavelength to metres. Three major factors limit the accuracy attainable with laser interferometers for a length measurement: Of these, the last


title: Metre content: is peculiar to the interferometer itself. The conversion of a length in wavelengths to a length in metres is based upon the relation which converts the unit of wavelength "λ" to metres using "c", the speed of light in vacuum in m/s. Here "n" is the refractive index of the medium in which the measurement is made, and "f" is the measured frequency of the source. Although conversion from wavelengths to metres introduces an additional error in the overall length due to measurement error in determining the refractive index and the frequency, the measurement of frequency is one of the


title: Metre content: most accurate measurements available. SI prefixes are often employed to denote decimal multiples and submultiples of the metre, as shown in the table below. As indicated in the table, some are commonly used, while others are not. Long distances are usually expressed in km, astronomical units (149.6 Gm), light-years (10 Pm), or parsecs (31 Pm), rather than in Mm, Gm, Tm, Pm, Em, Zm or Ym; "30 cm", "30 m", and "300 m" are more common than "3 dm", "3 dam", and "3 hm", respectively. The terms "micron" and (occasionally) "millimicron" are often used instead of "micrometre" (μm) and "nanometre"


title: Metre content: (nm), but this practice is officially discouraged. Within this table, "inch" and "yard" mean "international inch" and "international yard" respectively, though approximate conversions in the left column hold for both international and survey units. One metre is exactly equivalent to inches and to yards. A simple mnemonic aid exists to assist with conversion, as three "3"s: The ancient Egyptian cubit was about 0.5m (surviving rods are 523–529mm). Scottish and English definitions of the ell (two cubits) were 941mm (0.941m) and 1143mm (1.143m) respectively. The ancient Parisian "toise" (fathom) was slightly shorter than 2m and was standardised at exactly 2m in


title: Metre content: the mesures usuelles system, such that 1m was exactly toise. The Russian verst was 1.0668km. The Swedish mil was 10.688km, but was changed to 10km when Sweden converted to metric units. Metre The metre (British spelling and BIPM spelling) or meter (American spelling) (from the French unit "mètre", from the Greek noun μέτρον, "measure") is the base unit of length in some metric systems, including the International System of Units (SI). The SI unit symbol is m. The metre is defined as the length of the path travelled by light in a vacuum in second. The metre was originally defined


title: Medicine content: ethics discussions are: Values such as these do not give answers as to how to handle a particular situation, but provide a useful framework for understanding conflicts. When moral values are in conflict, the result may be an ethical dilemma or crisis. Sometimes, no good solution to a dilemma in medical ethics exists, and occasionally, the values of the medical community (i.e., the hospital and its staff) conflict with the values of the individual patient, family, or larger non-medical community. Conflicts can also arise between health care providers, or among family members. For example, some argue that the principles of


title: "Flowering plant" content: Flowering plant The flowering plants, also known as angiosperms, Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approximately 13,164 known genera and c. 369.000 known species. Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, and the production of fruits that contain the seeds. Etymologically, "angiosperm" means a plant that produces seeds within an enclosure; in other words, a fruiting plant. The term comes from the Greek words "angeion" ("case" or "casing") and sperma ("seed"). The ancestors of flowering plants diverged from gymnosperms


title: "Flowering plant" content: in the Triassic Period, 245 to 202 million years ago (mya), and the first flowering plants are known from 160 mya. They diversified extensively during the Early Cretaceous, became widespread by 120 mya, and replaced conifers as the dominant trees from 100 to 60 mya. Angiosperms differ from other seed plants in several ways, described in the table below. These distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants and the most commercially important group to humans. Angiosperm stems are made up of seven layers as shown above. The amount and complexity of tissue-formation


title: "Flowering plant" content: in flowering plants exceeds that of gymnosperms. The vascular bundles of the stem are arranged such that the xylem and phloem form concentric rings. In the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium. By the formation of a layer of cambium between the bundles (interfascicular cambium), a complete ring is formed, and a regular periodical increase in thickness results from the development of xylem on


title: "Flowering plant" content: the inside and phloem on the outside. The soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings. Among the monocotyledons, the bundles are more numerous in the young stem and are scattered through the ground tissue. They contain no cambium and once formed the stem increases in diameter only


title: "Flowering plant" content: in exceptional cases. The characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species. The function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf (where the petiole attaches to the stem). Occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. More typically, the flower-bearing portion of the plant is sharply distinguished from


title: "Flowering plant" content: the foliage-bearing or vegetative portion, and forms a more or less elaborate branch-system called an inflorescence. There are two kinds of reproductive cells produced by flowers. Microspores, which will divide to become pollen grains, are the "male" cells and are borne in the stamens (or microsporophylls). The "female" cells called megaspores, which will divide to become the egg cell (megagametogenesis), are contained in the ovule and enclosed in the carpel (or megasporophyll). The flower may consist only of these parts, as in willow, where each flower comprises only a few stamens or two carpels. Usually, other structures are present and


title: "Flowering plant" content: serve to protect the sporophylls and to form an envelope attractive to pollinators. The individual members of these surrounding structures are known as sepals and petals (or tepals in flowers such as "Magnolia" where sepals and petals are not distinguishable from each other). The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially the bud. The inner series (corolla of petals) is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators. Attraction is effected by color, scent, and


title: "Flowering plant" content: nectar, which may be secreted in some part of the flower. The characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans. While the majority of flowers are perfect or hermaphrodite (having both pollen and ovule producing parts in the same flower structure), flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization. Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot easily transfer pollen to the pistil (receptive part of the carpel). Homomorphic flowers may employ a biochemical (physiological) mechanism called self-incompatibility to discriminate


title: "Flowering plant" content: between self and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers. The botanical term "Angiosperm", from the Ancient Greek αγγείον, "angeíon" (bottle, vessel) and σπέρμα, (seed), was coined in the form Angiospermae by Paul Hermann in 1690, as the name of one of his primary divisions of the plant kingdom. This included flowering plants possessing seeds enclosed in capsules, distinguished from his Gymnospermae, or flowering plants with achenial or schizo-carpic fruits, the whole fruit or each of its pieces being here regarded as a seed and naked. The term and


title: "Flowering plant" content: its antonym were maintained by Carl Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any approach to its modern scope became possible only after 1827, when Robert Brown established the existence of truly naked ovules in the Cycadeae and Coniferae, and applied to them the name Gymnosperms. From that time onward, as long as these Gymnosperms were, as was usual, reckoned as dicotyledonous flowering plants, the term Angiosperm was used antithetically by botanical writers, with varying scope, as a group-name for other dicotyledonous plants. In 1851,


title: "Flowering plant" content: Hofmeister discovered the changes occurring in the embryo-sac of flowering plants, and determined the correct relationships of these to the Cryptogamia. This fixed the position of Gymnosperms as a class distinct from Dicotyledons, and the term Angiosperm then gradually came to be accepted as the suitable designation for the whole of the flowering plants other than Gymnosperms, including the classes of Dicotyledons and Monocotyledons. This is the sense in which the term is used today. In most taxonomies, the flowering plants are treated as a coherent group. The most popular descriptive name has been Angiospermae (Angiosperms), with Anthophyta ("flowering plants")


title: "Flowering plant" content: a second choice. These names are not linked to any rank. The Wettstein system and the Engler system use the name Angiospermae, at the assigned rank of subdivision. The Reveal system treated flowering plants as subdivision Magnoliophytina (Frohne & U. Jensen ex Reveal, Phytologia 79: 70 1996), but later split it to Magnoliopsida, Liliopsida, and Rosopsida. The Takhtajan system and Cronquist system treat this group at the rank of division, leading to the name Magnoliophyta (from the family name Magnoliaceae). The Dahlgren system and Thorne system (1992) treat this group at the rank of class, leading to the name Magnoliopsida.


title: "Flowering plant" content: The APG system of 1998, and the later 2003 and 2009 revisions, treat the flowering plants as a clade called angiosperms without a formal botanical name. However, a formal classification was published alongside the 2009 revision in which the flowering plants form the Subclass Magnoliidae. The internal classification of this group has undergone considerable revision. The Cronquist system, proposed by Arthur Cronquist in 1968 and published in its full form in 1981, is still widely used but is no longer believed to accurately reflect phylogeny. A consensus about how the flowering plants should be arranged has recently begun to emerge


title: "Flowering plant" content: through the work of the Angiosperm Phylogeny Group (APG), which published an influential reclassification of the angiosperms in 1998. Updates incorporating more recent research were published as the APG II system in 2003, the APG III system in 2009, and the APG IV system in 2016. Traditionally, the flowering plants are divided into two groups, which in the Cronquist system are called Magnoliopsida (at the rank of class, formed from the family name Magnoliaceae) and Liliopsida (at the rank of class, formed from the family name Liliaceae). Other descriptive names allowed by Article 16 of the ICBN include Dicotyledones or


title: "Flowering plant" content: Dicotyledoneae, and Monocotyledones or Monocotyledoneae, which have a long history of use. In English a member of either group may be called a dicotyledon (plural dicotyledons) and monocotyledon (plural monocotyledons), or abbreviated, as dicot (plural dicots) and monocot (plural monocots). These names derive from the observation that the dicots most often have two cotyledons, or embryonic leaves, within each seed. The monocots usually have only one, but the rule is not absolute either way. From a broad diagnostic point of view, the number of cotyledons is neither a particularly handy, nor a reliable character. Recent studies, as by the APG,


title: "Flowering plant" content: show that the monocots form a monophyletic group (clade) but that the dicots do not (they are paraphyletic). Nevertheless, the majority of dicot species do form a monophyletic group, called the eudicots or tricolpates. Of the remaining dicot species, most belong to a third major clade known as the magnoliids, containing about 9,000 species. The rest include a paraphyletic grouping of early branching taxa known collectively as the basal angiosperms, plus the families Ceratophyllaceae and Chloranthaceae. There are eight groups of living angiosperms: The exact relationship between these eight groups is not yet clear, although there is agreement that the


title: "Flowering plant" content: first three groups to diverge from the ancestral angiosperm were Amborellales, Nymphaeales, and Austrobaileyales. The term basal angiosperms refers to these three groups. Among the remaining five groups (core angiosperms), the relationship between the three broadest of these groups (magnoliids, monocots, and eudicots) remains unclear. Zeng and colleagues (Fig. 1) describe four competing schemes. Of these, eudicots and monocots are the largest and most diversified, with ~ 75% and 20% of angiosperm species, respectively. Some analyses make the magnoliids the first to diverge, others the monocots. "Ceratophyllum" seems to group with the eudicots rather than with the monocots. The 2016


title: "Flowering plant" content: Angiosperm Phylogeny Group revision (APG IV) retained the overall higher order relationship described in APG III. Fossilized spores suggest that higher plants (embryophytes) have lived on land for at least 475 million years. Early land plants reproduced sexually with flagellated, swimming sperm, like the green algae from which they evolved. An adaptation to terrestrialization was the development of upright meiosporangia for dispersal by spores to new habitats. This feature is lacking in the descendants of their nearest algal relatives, the Charophycean green algae. A later terrestrial adaptation took place with retention of the delicate, avascular sexual stage, the gametophyte, within


title: "Flowering plant" content: the tissues of the vascular sporophyte. This occurred by spore germination within sporangia rather than spore release, as in non-seed plants. A current example of how this might have happened can be seen in the precocious spore germination in "Selaginella", the spike-moss. The result for the ancestors of angiosperms was enclosing them in a case, the seed. The first seed bearing plants, like the ginkgo, and conifers (such as pines and firs), did not produce flowers. The pollen grains (male gametophytes) of "Ginkgo" and cycads produce a pair of flagellated, mobile sperm cells that "swim" down the developing pollen tube


title: "Flowering plant" content: to the female and her eggs. The apparently sudden appearance of nearly modern flowers in the fossil record initially posed such a problem for the theory of evolution that Charles Darwin called it an ""abominable mystery"". However, the fossil record has considerably grown since the time of Darwin, and recently discovered angiosperm fossils such as "Archaefructus", along with further discoveries of fossil gymnosperms, suggest how angiosperm characteristics may have been acquired in a series of steps. Several groups of extinct gymnosperms, in particular seed ferns, have been proposed as the ancestors of flowering plants, but there is no continuous fossil


title: "Flowering plant" content: evidence showing exactly how flowers evolved. Some older fossils, such as the upper Triassic "Sanmiguelia", have been suggested. Based on current evidence, some propose that the ancestors of the angiosperms diverged from an unknown group of gymnosperms in the Triassic period (245–202 million years ago). Fossil angiosperm-like pollen from the Middle Triassic (247.2–242.0 Ma) suggests an older date for their origin. A close relationship between angiosperms and gnetophytes, proposed on the basis of morphological evidence, has more recently been disputed on the basis of molecular evidence that suggest gnetophytes are instead more closely related to other gymnosperms. The evolution of


title: "Flowering plant" content: seed plants and later angiosperms appears to be the result of two distinct rounds of whole genome duplication events. These occurred at and . Another possible whole genome duplication event at perhaps created the ancestral line that led to all modern flowering plants. That event was studied by sequencing the genome of an ancient flowering plant, "Amborella trichopoda", and directly addresses Darwin's ""abominable mystery"." The earliest known macrofossil confidently identified as an angiosperm, "Archaefructus liaoningensis", is dated to about 125 million years BP (the Cretaceous period), whereas pollen considered to be of angiosperm origin takes the fossil record back to


title: "Flowering plant" content: about 130 million years BP. However, one study has suggested that the early-middle Jurassic plant "Schmeissneria", traditionally considered a type of ginkgo, may be the earliest known angiosperm, or at least a close relative. In 2018, scientists reported that the earliest flowers began about 180 million years ago, 50 million years earlier than thought earlier. Nonetheless, circumstantial chemical evidence has been found for the existence of angiosperms as early as 250 million years ago. Oleanane, a secondary metabolite produced by many flowering plants, has been found in Permian deposits of that age together with fossils of gigantopterids. Gigantopterids are a


title: "Flowering plant" content: group of extinct seed plants that share many morphological traits with flowering plants, although they are not known to have been flowering plants themselves. In 2013 flowers encased in amber were found and dated 100 million years before present. The amber had frozen the act of sexual reproduction in the process of taking place. Microscopic images showed tubes growing out of pollen and penetrating the flower's stigma. The pollen was sticky, suggesting it was carried by insects. Recent DNA analysis based on molecular systematics showed that "Amborella trichopoda", found on the Pacific island of New Caledonia, belongs to a sister


title: "Flowering plant" content: group of the other flowering plants, and morphological studies suggest that it has features that may have been characteristic of the earliest flowering plants. The orders Amborellales, Nymphaeales, and Austrobaileyales diverged as separate lineages from the remaining angiosperm clade at a very early stage in flowering plant evolution. The great angiosperm radiation, when a great diversity of angiosperms appears in the fossil record, occurred in the mid-Cretaceous (approximately 100 million years ago). However, a study in 2007 estimated that the division of the five most recent (the genus "Ceratophyllum", the family Chloranthaceae, the eudicots, the magnoliids, and the monocots) of


title: "Flowering plant" content: the eight main groups occurred around 140 million years ago. By the late Cretaceous, angiosperms appear to have dominated environments formerly occupied by ferns and cycadophytes, but large canopy-forming trees replaced conifers as the dominant trees only close to the end of the Cretaceous 66 million years ago or even later, at the beginning of the Tertiary. The radiation of herbaceous angiosperms occurred much later. Yet, many fossil plants recognizable as belonging to modern families (including beech, oak, maple, and magnolia) had already appeared by the late Cretaceous. It has been proposed that the swift rise of angiosperms to dominance


title: "Flowering plant" content: was facilitated by a reduction in their genome size. During the early Cretaceous period, only angiosperms underwent rapid genome downsizing, while genome sizes of ferns and gymnosperms remained unchanged. Smaller genomes–and smaller nuclei–allow for faster rates of cell division and smaller cells. Thus, species with smaller genomes can pack more, smaller cells–in particular veins and stomata–into a given leaf volume. Genome downsizing therefore facilitated higher rates of leaf gas exchange (transpiration and photosynthesis) and faster rates of growth. This would have countered some of the negative physiological effects of genome duplications, facilitated increased uptake of carbon dioxide despite concurrent declines


title: "Flowering plant" content: in atmospheric CO concentrations, and allowed the flowering plants to outcompete other land plants. It is generally assumed that the function of flowers, from the start, was to involve mobile animals in their reproduction processes. That is, pollen can be scattered even if the flower is not brightly colored or oddly shaped in a way that attracts animals; however, by expending the energy required to create such traits, angiosperms can enlist the aid of animals and, thus, reproduce more efficiently. Island genetics provides one proposed explanation for the sudden, fully developed appearance of flowering plants. Island genetics is believed to


title: "Flowering plant" content: be a common source of speciation in general, especially when it comes to radical adaptations that seem to have required inferior transitional forms. Flowering plants may have evolved in an isolated setting like an island or island chain, where the plants bearing them were able to develop a highly specialized relationship with some specific animal (a wasp, for example). Such a relationship, with a hypothetical wasp carrying pollen from one plant to another much the way fig wasps do today, could result in the development of a high degree of specialization in both the plant(s) and their partners. Note that


title: "Flowering plant" content: the wasp example is not incidental; bees, which, it is postulated, evolved specifically due to mutualistic plant relationships, are descended from wasps. Animals are also involved in the distribution of seeds. Fruit, which is formed by the enlargement of flower parts, is frequently a seed-dispersal tool that attracts animals to eat or otherwise disturb it, incidentally scattering the seeds it contains (see frugivory). Although many such mutualistic relationships remain too fragile to survive competition and to spread widely, flowering proved to be an unusually effective means of reproduction, spreading (whatever its origin) to become the dominant form of land plant


title: "Flowering plant" content: life. Flower ontogeny uses a combination of genes normally responsible for forming new shoots. The most primitive flowers probably had a variable number of flower parts, often separate from (but in contact with) each other. The flowers tended to grow in a spiral pattern, to be bisexual (in plants, this means both male and female parts on the same flower), and to be dominated by the ovary (female part). As flowers evolved, some variations developed parts fused together, with a much more specific number and design, and with either specific sexes per flower or plant or at least "ovary-inferior". Flower


title: "Flowering plant" content: evolution continues to the present day; modern flowers have been so profoundly influenced by humans that some of them cannot be pollinated in nature. Many modern domesticated flower species were formerly simple weeds, which sprouted only when the ground was disturbed. Some of them tended to grow with human crops, perhaps already having symbiotic companion plant relationships with them, and the prettiest did not get plucked because of their beauty, developing a dependence upon and special adaptation to human affection. A few paleontologists have also proposed that flowering plants, or angiosperms, might have evolved due to interactions with dinosaurs. One


title: "Flowering plant" content: of the idea's strongest proponents is Robert T. Bakker. He proposes that herbivorous dinosaurs, with their eating habits, provided a selective pressure on plants, for which adaptations either succeeded in deterring or coping with predation by herbivores. In August 2017, scientists presented a detailed description and 3D model image of what the first flower possibly looked like, and presented the hypothesis that it may have lived about 140 million years ago. A Bayesian analysis of 52 angiosperm taxa suggested that the crown group of angiosperms evolved between and . The number of species of flowering plants is estimated to be


title: "Flowering plant" content: in the range of 250,000 to 400,000. This compares to around 12,000 species of moss or 11,000 species of pteridophytes, showing that the flowering plants are much more diverse. The number of families in APG (1998) was 462. In APG II (2003) it is not settled; at maximum it is 457, but within this number there are 55 optional segregates, so that the minimum number of families in this system is 402. In APG III (2009) there are 415 families. The diversity of flowering plants is not evenly distributed. Nearly all species belong to the eudicot (75%), monocot (23%), and


title: "Flowering plant" content: magnoliid (2%) clades. The remaining 5 clades contain a little over 250 species in total; i.e. less than 0.1% of flowering plant diversity, divided among 9 families. The 43 most-diverse of 443 families of flowering plants by species, in their APG circumscriptions, are Of these, the Orchidaceae, Poaceae, Cyperaceae, Araceae, Bromeliaceae, Arecaceae, and Iridaceae are monocot families; Piperaceae, Lauraceae, and Annonaceae are magnoliid dicots; the rest of the families are eudicots. Double fertilization refers to a process in which two sperm cells fertilize cells in the ovule. This process begins when a pollen grain adheres to the stigma of the


title: "Flowering plant" content: pistil (female reproductive structure), germinates, and grows a long pollen tube. While this pollen tube is growing, a haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid ("n") sperm cells. As the pollen tube grows, it makes its way from the stigma, down the style and into the ovary. Here the pollen tube reaches the micropyle of the ovule and digests its way into one of the synergids, releasing its contents (which include the sperm cells). The synergid that the cells were released into degenerates and one sperm


title: "Flowering plant" content: makes its way to fertilize the egg cell, producing a diploid (2"n") zygote. The second sperm cell fuses with both central cell nuclei, producing a triploid (3"n") cell. As the zygote develops into an embryo, the triploid cell develops into the endosperm, which serves as the embryo's food supply. The ovary will now develop into a fruit and the ovule will develop into a seed. As the development of embryo and endosperm proceeds within the embryo sac, the sac wall enlarges and combines with the nucellus (which is likewise enlarging) and the integument to form the "seed coat". The ovary


title: "Flowering plant" content: wall develops to form the fruit or pericarp, whose form is closely associated with type of seed dispersal system. Frequently, the influence of fertilization is felt beyond the ovary, and other parts of the flower take part in the formation of the fruit, e.g., the floral receptacle in the apple, strawberry, and others. The character of the seed coat bears a definite relation to that of the fruit. They protect the embryo and aid in dissemination; they may also directly promote germination. Among plants with indehiscent fruits, in general, the fruit provides protection for the embryo and secures dissemination. In


title: "Flowering plant" content: this case, the seed coat is only slightly developed. If the fruit is dehiscent and the seed is exposed, in general, the seed-coat is well developed, and must discharge the functions otherwise executed by the fruit. Flowering plants generate gametes using a specialized cell division called meiosis. Meiosis takes place in the ovule (a structure within the ovary that is located within the pistil at the center of the flower) (see diagram labeled "Angiosperm lifecycle"). A diploid cell (megaspore mother cell) in the ovule undergoes meiosis (involving two successive cell divisions) to produce four cells (megaspores) with haploid nuclei. One


title: "Flowering plant" content: of these four cells (megaspore) then undergoes three successive mitotic divisions to produce an immature embryo sac (megagametophyte) with eight haploid nuclei. Next, these nuclei are segregated into separate cells by cytokinesis to producing 3 antipodal cells, 2 synergid cells and an egg cell. Two polar nuclei are left in the central cell of the embryo sac. Pollen is also produced by meiosis in the male anther (microsporangium). During meiosis, a diploid microspore mother cell undergoes two successive meiotic divisions to produce 4 haploid cells (microspores or male gametes). Each of these microspores, after further mitoses, becomes a pollen grain


title: "Flowering plant" content: (microgametophyte) containing two haploid generative (sperm) cells and a tube nucleus. When a pollen grain makes contact with the female stigma, the pollen grain forms a pollen tube that grows down the style into the ovary. In the act of fertilization, a male sperm nucleus fuses with the female egg nucleus to form a diploid zygote that can then develop into an embryo within the newly forming seed. Upon germination of the seed, a new plant can grow and mature. The adaptive function of meiosis is currently a matter of debate. A key event during meiosis in a diploid cell


title: "Flowering plant" content: is the pairing of homologous chromosomes and homologous recombination (the exchange of genetic information) between homologous chromosomes. This process promotes the production of increased genetic diversity among progeny and the recombinational repair of damages in the DNA to be passed on to progeny. To explain the adaptive function of meiosis in flowering plants, some authors emphasize diversity and others emphasize DNA repair. Apomixis (reproduction via asexually formed seeds) is found naturally in about 2.2% of angiosperm genera. One type of apomixis, gametophytic apomixis found in a dandelion species involves formation of an unreduced embryo sac due to incomplete meiosis (apomeiosis)


title: "Flowering plant" content: and development of an embryo from the unreduced egg inside the embryo sac, without fertilization (parthenogenesis). Agriculture is almost entirely dependent on angiosperms, which provide virtually all plant-based food, and also provide a significant amount of livestock feed. Of all the families of plants, the Poaceae, or grass family (providing grains), is by far the most important, providing the bulk of all feedstocks (rice, maize, wheat, barley, rye, oats, pearl millet, sugar cane, sorghum). The Fabaceae, or legume family, comes in second place. Also of high importance are the Solanaceae, or nightshade family (potatoes, tomatoes, and peppers, among others); the


title: "Flowering plant" content: Cucurbitaceae, or gourd family (including pumpkins and melons); the Brassicaceae, or mustard plant family (including rapeseed and the innumerable varieties of the cabbage species "Brassica oleracea"); and the Apiaceae, or parsley family. Many of our fruits come from the Rutaceae, or rue family (including oranges, lemons, grapefruits, etc.), and the Rosaceae, or rose family (including apples, pears, cherries, apricots, plums, etc.). In some parts of the world, certain single species assume paramount importance because of their variety of uses, for example the coconut ("Cocos nucifera") on Pacific atolls, and the olive ("Olea europaea") in the Mediterranean region. Flowering plants also


title: "Flowering plant" content: provide economic resources in the form of wood, paper, fiber (cotton, flax, and hemp, among others), medicines (digitalis, camphor), decorative and landscaping plants, and many other uses. The main area in which they are surpassed by other plants—namely, coniferous trees (Pinales), which are non-flowering (gymnosperms)—is timber and paper production. Flowering plant The flowering plants, also known as angiosperms, Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approximately 13,164 known genera and c. 369.000 known species. Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the


title: "Muscular dystrophy" content: Muscular dystrophy Muscular dystrophy (MD) is a group of muscle diseases that results in increasing weakening and breakdown of skeletal muscles over time. The disorders differ in which muscles are primarily affected, the degree of weakness, how fast they worsen, and when symptoms begin. Many people will eventually become unable to walk. Some types are also associated with problems in other organs. The muscular dystrophy group contains thirty different genetic disorders that are usually classified into nine main categories or types. The most common type is Duchenne muscular dystrophy (DMD) which typically affects males beginning around the age of four.


title: Manganese content: produce a parkinsonism-like illness characterized by movement abnormalities. This condition is not responsive to typical therapies used in the treatment of PD, suggesting an alternative pathway than the typical dopaminergic loss within the substantia nigra. Manganese may accumulate in the basal ganglia, leading to the abnormal movements. A mutation of the SLC30A10 gene, a manganese efflux transporter necessary for decreasing intracellular Mn, has been linked with the development of this Parkinsonism-like disease. The Lewy bodies typical to PD are not seen in Mn-induced parkinsonism. Animal experiments have given the opportunity to examine the consequences of manganese overexposure under controlled conditions.


title: "Geography of Macau" content: both defines and obscures its topography. The Macau Peninsula is narrow in shape but varies in terrain. Although Macau is located in the tropics, it has a humid subtropical climate (Köppen climate classification "Cwa"), because the Siberian pressure system in the winter pushes cool air further south than similar semipermanent permanent high pressure systems. Its average year-round temperature is . Summers are very hot and humid: the July average temperature is and the highest daytime temperature could reach . However, the heat is generally less intense than many places in mainland China due to the coastal location. Winters are short


title: "Transport in Malaysia" content: the most important shipping lanes in the world. Malaysia has two ports that are listed in the top 20 busiest ports in the world, Port Klang and Port of Tanjung Pelepas, which are, respectively, the second- and third-busiest ports in Southeast Asia after the Port of Singapore. Port Klang is Malaysia's busiest port, and the thirteenth-busiest port in the world in 2013, handling over 10.3 million TEUs. Port of Tanjung Pelepas is Malaysia's second-busiest port, and the nineteenth-busiest port in the world in 2013, handling over 7.6 million TEUs. This is a list of Malaysian ports and harbours: Total: 360


title: "Demographics of Mozambique" content: 93% of the Bantu population was illiterate, and many could not speak Portuguese. In fact, most of today's political leaders were educated in missionary schools. After independence, the government placed a high priority on expanding education, which reduced the illiteracy rate to about two-thirds as primary school enrollment increased. Unfortunately, in recent years school construction and teacher training enrollments have not kept up with population increases. With post-war enrollments reaching all-time highs, the quality of education has suffered. As a member of Commonwealth of Nations, most urban Mozambicans are required to learn English starting high-school. The following demographic statistics are


title: "Little Boy" content: the explosion was completely destroyed, except for about 50 heavily reinforced, earthquake-resistant concrete buildings, only the shells of which remained standing. Most were completely gutted, with their windows, doors, sashes, and frames ripped out. The perimeter of severe blast damage approximately followed the contour at . Later test explosions of nuclear weapons with houses and other test structures nearby confirmed the 5 psi overpressure threshold. Ordinary urban buildings experiencing it will be crushed, toppled, or gutted by the force of air pressure. The picture at right shows the effects of a nuclear-bomb-generated 5 psi pressure wave on a test structure


title: Lilith content: listed in The Assyrian Dictionary of the Oriental Institute of the University of Chicago (CAD, 1956, L.190), in Wolfram von Soden's "Akkadisches Handwörterbuch" (AHw, p. 553), and "Reallexikon der Assyriologie" (RLA, p. 47). The Sumerian female demons "lili" have no etymological relation to Akkadian "lilu", "evening". Archibald Sayce (1882) considered that Hebrew "lilit" (or "lilith") and the earlier Akkadian "līlītu" are from proto-Semitic. Charles Fossey (1902) has this literally translating to "female night being/demon", although cuneiform inscriptions from Mesopotamia exist where "Līlīt" and "Līlītu" refers to disease-bearing wind spirits. Another possibility is association not with "night", but with "wind", thus


title: "Legion of Merit" content: in the performance of outstanding services and achievements" and is typically reserved for senior officers at O-6 level and above, typically in connection with senior leadership/command positions or other senior positions of significant responsibility. The degrees and the design of the decoration were influenced by the French Legion of Honour ("Légion d'honneur"). Although recommendations for creation of a Meritorious Service Medal were initiated as early as September 1937, no formal action was taken toward approval. In a letter to the Quartermaster General (QMG) dated December 24, 1941, the Adjutant General formally requested action be initiated to create a Meritorious Service


title: "Spam (Monty Python)" content: Python libraries. Spam makers Hormel, while never happy with the use of the word "spam" for junk email, have been supportive of Monty Python and their sketch. Hormel issued a special tin of Spam for the Broadway premiere of Eric Idle's "Spamalot", a musical based on "Monty Python and the Holy Grail". The sketch is part of the company's Spam Museum in Austin, Minnesota, United States, and also mentioned in Spam's on-can advertisements for the product's 70th anniversary in 2007 - although the date of the Python sketch was incorrectly stated to be 1971 instead of 1970. In 2007 the


title: Mauritius content: its first recorded visit during the Middle Ages by Arab sailors, who named it Dina Arobi. In 1507, Portuguese sailors came to the uninhabited island and established a visiting base. Diogo Fernandes Pereira, a Portuguese navigator, was the first European known to land in Mauritius. He named the island "Ilha do Cirne". The Portuguese did not stay long as they were not interested in these islands. In 1598 a Dutch squadron under Admiral Wybrand van Warwyck landed at Grand Port and named the island "Mauritius" after Prince Maurice van Nassau of the Dutch Republic. The Dutch inhabited the island in


title: "Foreign relations of Mauritius" content: state of the United Nations and the Commonwealth of Nations since independence in 1968. It is a member of the World Trade Organization, La Francophonie, Organisation of African Unity, the Southern Africa Development Community, the Indian Ocean Commission, COMESA, and the recently formed Indian Ocean Rim Association. Foreign relations of Mauritius Mauritius has strong and friendly relations with the West, as well as with South Asian countries and the countries of southern and eastern Africa. It is a member of the World Trade Organization, the Commonwealth of Nations, La Francophonie, the African Union, the Southern Africa Development Community, the Indian


title: "Economy of Mexico" content: have been founded such as Aeromarmi, which builds light propeller airplanes, and Hydra Technologies, which builds Unmanned Aerial Vehicles such as the S4 Ehécatl, other important companies are Frisa Aerospace that manufactures jet engine parts for the new Mitsubishi Regional jet and supplies Prat&whittney and rolls Royce jet engine manufacturers of casings for jet engines and Kuo Aerospace that builds parts for aircraft landing gear and Supplies bombardier plant in Querétaro. As compared with the United States or countries in Western Europe a larger sector of Mexico's industrial economy is food manufacturing which includes several world class companies but the


title: "Mahatma Gandhi" content: close parallels do exist in programs of social reform in the Swaminarayan tradition and those of Gandhi, based on "nonviolence, truth-telling, cleanliness, temperance and upliftment of the masses." Historian Howard states the culture of Gujarat influenced Gandhi and his methods. Along with the book mentioned above, in 1908 Leo Tolstoy wrote "A Letter to a Hindu," which said that only by using love as a weapon through passive resistance could the Indian people overthrow colonial rule. In 1909, Gandhi wrote to Tolstoy seeking advice and permission to republish "A Letter to a Hindu" in Gujarati. Tolstoy responded and the two


title: MySQL content: approval of the merger". But, as revealed by WikiLeaks, the US Department of Justice, at the request of Oracle, pressured the EU to approve the merger unconditionally. The European Commission eventually unconditionally approved Oracle's acquisition of MySQL AB on 21 January 2010. In January 2010, before Oracle's acquisition of MySQL AB, Monty Widenius started a GPL-only fork, MariaDB. MariaDB is based on the same code base as MySQL server 5.5 and aims to maintain compatibility with Oracle-provided versions. MySQL is offered under two different editions: the open source MySQL Community Server and the proprietary Enterprise Server. MySQL Enterprise Server is


title: Microscope content: Microscope A microscope (from the , "mikrós", "small" and , "skopeîn", "to look" or "see") is an instrument used to see objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using such an instrument. Microscopic means invisible to the eye unless aided by a microscope. There are many types of microscopes, and they may be grouped in different ways. One way is to describe the way the instruments interact with a sample to create images, either by sending a beam of light or electrons to a sample


title: Microscope content: in its optical path, or by scanning across, and a short distance from, the surface of a sample using a probe. The most common microscope (and the first to be invented) is the optical microscope, which uses light to pass through a sample to produce an image. Other major types of microscopes are the fluorescence microscope, the electron microscope (both, the transmission electron microscope and the scanning electron microscope) and the various types of scanning probe microscopes. Although objects resembling lenses date back 4000 years and there are Greek accounts of the optical properties of water-filled spheres (5th century BC)


title: Microscope content: followed by many centuries of writings on optics, the earliest known use of simple microscopes (magnifying glasses) dates back to the widespread use of lenses in eyeglasses in the 13th century. The earliest known examples of compound microscopes, which combine an objective lens near the specimen with an eyepiece to view a real image, appeared in Europe around 1620. The inventor is unknown although many claims have been made over the years. Several revolve around the spectacle-making centers in the Netherlands including claims it was invented in 1590 by Zacharias Janssen (claim made by his son) and/or Zacharias' father, Hans


title: Microscope content: Martens, claims it was invented by their neighbor and rival spectacle maker, Hans Lippershey (who applied for the first telescope patent in 1608), and claims it was invented by expatriate Cornelis Drebbel who was noted to have a version in London in 1619. Galileo Galilei (also sometimes cited as compound microscope inventor) seems to have found after 1610 that he could close focus his telescope to view small objects and, after seeing a compound microscope built by Drebbel exhibited in Rome in 1624, built his own improved version. Giovanni Faber coined the name "microscope" for the compound microscope Galileo submitted


title: Microscope content: to the Accademia dei Lincei in 1625 (Galileo had called it the ""occhiolino"" or ""little eye""). The first detailed account of the microscopic anatomy of organic tissue based on the use of a microscope did not appear until 1644, in Giambattista Odierna's "L'occhio della mosca", or "The Fly's Eye". The microscope was still largely a novelty until the 1660s and 1670s when naturalists in Italy, the Netherlands and England began using them to study biology, both organisms and their ultrastructure. Italian scientist Marcello Malpighi, called the father of histology by some historians of biology, began his analysis of biological structures


title: Microscope content: with the lungs. Robert Hooke's "Micrographia" had a huge impact, largely because of its impressive illustrations. A significant contribution came from Antonie van Leeuwenhoek who achieved up to 300 times magnification using a simple single lens microscope. He sandwiched a very small glass ball lens between the holes in two metal plates riveted together, and with an adjustable-by-screws needle attached to mount the specimen. Then, Van Leeuwenhoek re-discovered red blood cells (after Jan Swammerdam) and spermatozoa, and helped popularise the use of microscopes to view biological ultrastructure. On 9 October 1676, van Leeuwenhoek reported the discovery of micro-organisms. The performance


title: Microscope content: of a light microscope depends on the quality and correct use of the condensor lens system to focus light on the specimen and the objective lens to capture the light from the specimen and form an image. Early instruments were limited until this principle was fully appreciated and developed from the late 19th to very early 20th century, and until electric lamps were available as light sources. In 1893 August Köhler developed a key principle of sample illumination, Köhler illumination, which is central to achieving the theoretical limits of resolution for the light microscope. This method of sample illumination produces


title: Microscope content: even lighting and overcomes the limited contrast and resolution imposed by early techniques of sample illumination. Further developments in sample illumination came from the discovery of phase contrast by Frits Zernike in 1953, and differential interference contrast illumination by Georges Nomarski in 1955; both of which allow imaging of unstained, transparent samples. In the early 20th century a significant alternative to the light microscope was developed, an instrument that uses a beam of electrons rather than light to generate an image. The German physicist, Ernst Ruska, working with electrical engineer Max Knoll, developed the first prototype electron microscope in 1931,


title: Microscope content: a transmission electron microscope (TEM). The transmission electron microscope works on similar principles to an optical microscope but uses electrons in the place of light and electromagnets in the place of glass lenses. Use of electrons, instead of light, allows for much higher resolution. Development of the transmission electron microscope was quickly followed in 1935 by the development of the scanning electron microscope by Max Knoll. Although TEMs were being used for research before WWII, and became popular afterwards, the SEM was not commercially available until 1965. Transmission electron microscopes became popular following the Second World War. Ernst Ruska, working


title: Microscope content: at Siemens, developed the first commercial transmission electron microscope and, in the 1950s, major scientific conferences on electron microscopy started being held. In 1965, the first commercial scanning electron microscope was developed by Professor Sir Charles Oatley and his postgraduate student Gary Stewart, and marketed by the Cambridge Instrument Company as the "Stereoscan". One of the latest discoveries made about using an electron microscope is the ability to identify a virus. Since this microscope produces a visible, clear image of small organelles, in an electron microscope there is no need for reagents to see the virus or harmful cells, resulting


title: Microscope content: in a more efficient way to detect pathogens. From 1981 to 1983 Gerd Binnig and Heinrich Rohrer worked at IBM in Zurich, Switzerland to study the quantum tunnelling phenomenon. They created a practical instrument, a scanning probe microscope from quantum tunnelling theory, that read very small forces exchanged between a probe and the surface of a sample. The probe approaches the surface so closely that electrons can flow continuously between probe and sample, making a current from surface to probe. The microscope was not initially well received due to the complex nature of the underlying theoretical explanations. In 1984 Jerry


title: Microscope content: Tersoff and D.R. Hamann, while at AT&T's Bell Laboratories in Murray Hill, New Jersey began publishing articles that tied theory to the experimental results obtained by the instrument. This was closely followed in 1985 with functioning commercial instruments, and in 1986 with Gerd Binnig, Quate, and Gerber's invention of the atomic force microscope, then Binnig's and Rohrer's Nobel Prize in Physics for the SPM. New types of scanning probe microscope have continued to be developed as the ability to machine ultra-fine probes and tips has advanced. The most recent developments in light microscope largely centre on the rise of fluorescence


title: Microscope content: microscopy in biology. During the last decades of the 20th century, particularly in the post-genomic era, many techniques for fluorescent staining of cellular structures were developed. The main groups of techniques involve targeted chemical staining of particular cell structures, for example, the chemical compound DAPI to label DNA, use of antibodies conjugated to fluorescent reporters, see immunofluorescence, and fluorescent proteins, such as green fluorescent protein. These techniques use these different fluorophores for analysis of cell structure at a molecular level in both live and fixed samples. The rise of fluorescence microscopy drove the development of a major modern microscope design,


title: Microscope content: the confocal microscope. The principle was patented in 1957 by Marvin Minsky, although laser technology limited practical application of the technique. It was not until 1978 when Thomas and Christoph Cremer developed the first practical confocal laser scanning microscope and the technique rapidly gained popularity through the 1980s. Much current research (in the early 21st century) on optical microscope techniques is focused on development of superresolution analysis of fluorescently labelled samples. Structured illumination can improve resolution by around two to four times and techniques like stimulated emission depletion (STED) microscopy are approaching the resolution of electron microscopes. This occurs because


title: Microscope content: the diffraction limit is occurred from light or excitation, which makes the resolution must be doubled to become super saturated. Stefan Hell was awarded the 2014 Nobel Prize in Chemistry for the development of the STED technique, along with Eric Betzig and William Moerner who adapted fluorescnence microscopy for single-molecule viusalization. X-ray microscopes are instruments that use electromagnetic radiation usually in the soft X-ray band to image objects. Technological advances in x-ray lens optics in the early 1970s made the instrument a viable imaging choice. They are often used in tomography (see micro-computed tomography) to produce three dimensional images of


title: Microscope content: objects, including biological materials that have not been chemically fixed. Currently research is being done to improve optics for hard x-rays which have greater penetrating power. Microscopes can be separated into several different classes. One grouping is based on what interacts with the sample to generate the image, i.e., light or photons (optical microscopes), electrons (electron microscopes) or a probe (scanning probe microscopes). Alternatively, microscopes can be classified based on whether they analyze the sample via a scanning point (confocal optical microscopes, scanning electron microscopes and scanning probe microscopes) or analyze the sample all at once (wide field optical microscopes


title: Microscope content: and transmission electron microscopes). Wide field optical microscopes and transmission electron microscopes both use the theory of lenses (optics for light microscopes and electromagnet lenses for electron microscopes) in order to magnify the image generated by the passage of a wave transmitted through the sample, or reflected by the sample. The waves used are electromagnetic (in optical microscopes) or electron beams (in electron microscopes). Resolution in these microscopes is limited by the wavelength of the radiation used to image the sample, where shorter wavelengths allow for a higher resolution. Scanning optical and electron microscopes, like the confocal microscope and scanning


title: Microscope content: electron microscope, use lenses to focus a spot of light or electrons onto the sample then analyze the signals generated by the beam interacting with the sample. The point is then scanned over the sample to analyze a rectangular region. Magnification of the image is achieved by displaying the data from scanning a physically small sample area on a relatively large screen. These microscopes have the same resolution limit as wide field optical, probe, and electron microscopes. Scanning probe microscopes also analyze a single point in the sample and then scan the probe over a rectangular sample region to build


title: Microscope content: up an image. As these microscopes do not use electromagnetic or electron radiation for imaging they are not subject to the same resolution limit as the optical and electron microscopes described above. The most common type of microscope (and the first invented) is the optical microscope. This is an optical instrument containing one or more lenses producing an enlarged image of a sample placed in the focal plane. Optical microscopes have refractive glass (occasionally plastic or quartz), to focus light on the eye or on to another light detector. Mirror-based optical microscopes operate in the same manner. Typical magnification of


title: Microscope content: a light microscope, assuming visible range light, is up to 1250x with a theoretical resolution limit of around 0.250 micrometres or 250 nanometres. This limits practical magnification to ~1500x. Specialized techniques (e.g., scanning confocal microscopy, Vertico SMI) may exceed this magnification but the resolution is diffraction limited. The use of shorter wavelengths of light, such as ultraviolet, is one way to improve the spatial resolution of the optical microscope, as are devices such as the near-field scanning optical microscope. Sarfus is a recent optical technique that increases the sensitivity of a standard optical microscope to a point where it is


title: Microscope content: possible to directly visualize nanometric films (down to 0.3 nanometre) and isolated nano-objects (down to 2 nm-diameter). The technique is based on the use of non-reflecting substrates for cross-polarized reflected light microscopy. Ultraviolet light enables the resolution of microscopic features as well as the imaging of samples that are transparent to the eye. Near infrared light can be used to visualize circuitry embedded in bonded silicon devices, since silicon is transparent in this region of wavelengths. In fluorescence microscopy many wavelengths of light ranging from the ultraviolet to the visible can be used to cause samples to fluoresce which allows


title: Microscope content: viewing by eye or with specifically sensitive cameras. Phase contrast microscopy is an optical microscopy illumination technique in which small phase shifts in the light passing through a transparent specimen are converted into amplitude or contrast changes in the image. The use of phase contrast does not require staining to view the slide. This microscope technique made it possible to study the cell cycle in live cells. The traditional optical microscope has more recently evolved into the digital microscope. In addition to, or instead of, directly viewing the object through the eyepieces, a type of sensor similar to those used