The Celsius scale known as the centigrade scale, is a temperature scale used by the International System of Units. As an SI derived unit, it is used by all countries except the United States, the Bahamas, the Cayman Islands and Liberia, it is named after the Swedish astronomer Anders Celsius. The degree Celsius can refer to a specific temperature on the Celsius scale or a unit to indicate a difference between two temperatures or an uncertainty. Before being renamed to honor Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, gradus, which means steps. From 1743, the Celsius scale is based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure. Prior to 1743, the scale was based on the boiling and melting points of water, but the values were reversed; the 1743 scale reversal was proposed by Jean-Pierre Christin. By international agreement, since 1954 the unit degree Celsius and the Celsius scale are defined by absolute zero and the triple point of Vienna Standard Mean Ocean Water, a specially purified water.
This definition precisely relates the Celsius scale to the Kelvin scale, which defines the SI base unit of thermodynamic temperature with symbol K. Absolute zero, the lowest temperature possible, is defined as being 0 K and −273.15 °C. The temperature of the triple point of water is defined as 273.16 K. This means that a temperature difference of one degree Celsius and that of one kelvin are the same. On 20 May 2019, the kelvin, along with it the degree Celsius, will be redefined so that its value will be determined by definition of the Boltzmann constant. In 1742, Swedish astronomer Anders Celsius created a temperature scale, the reverse of the scale now known as "Celsius": 0 represented the boiling point of water, while 100 represented the freezing point of water. In his paper Observations of two persistent degrees on a thermometer, he recounted his experiments showing that the melting point of ice is unaffected by pressure, he determined with remarkable precision how the boiling point of water varied as a function of atmospheric pressure.
He proposed that the zero point of his temperature scale, being the boiling point, would be calibrated at the mean barometric pressure at mean sea level. This pressure is known as one standard atmosphere; the BIPM's 10th General Conference on Weights and Measures defined one standard atmosphere to equal 1,013,250 dynes per square centimetre. In 1743, the Lyonnais physicist Jean-Pierre Christin, permanent secretary of the Académie des sciences, belles-lettres et arts de LyonAcadémie des sciences, belles-lettres et arts de Lyon, working independently of Celsius, developed a scale where zero represented the freezing point of water and 100 represented the boiling point of water. On 19 May 1743 he published the design of a mercury thermometer, the "Thermometer of Lyon" built by the craftsman Pierre Casati that used this scale. In 1744, coincident with the death of Anders Celsius, the Swedish botanist Carl Linnaeus reversed Celsius's scale, his custom-made "linnaeus-thermometer", for use in his greenhouses, was made by Daniel Ekström, Sweden's leading maker of scientific instruments at the time, whose workshop was located in the basement of the Stockholm observatory.
As happened in this age before modern communications, numerous physicists and instrument makers are credited with having independently developed this same scale. The first known Swedish document reporting temperatures in this modern "forward" Celsius scale is the paper Hortus Upsaliensis dated 16 December 1745 that Linnaeus wrote to a student of his, Samuel Nauclér. In it, Linnaeus recounted the temperatures inside the orangery at the University of Uppsala Botanical Garden:...since the caldarium by the angle of the windows from the rays of the sun, obtains such heat that the thermometer reaches 30 degrees, although the keen gardener takes care not to let it rise to more than 20 to 25 degrees, in winter not under 15 degrees... Since the 19th century, the scientific and thermometry communities worldwide have used the phrase "centigrade scale". Temperatures on the centigrade scale were reported as degrees or, when greater specificity was desired, as degrees centigrade; because the term centigrade was the Spanish and French language name for a unit of angular measurement and had a similar connotation in other languages, the term centesimal degree was used when precise, unambiguous language was required by international standards bodies such as the BIPM.
More properly, what was defined as "centigrade" would now be "hectograde". To eliminate any confusion, the 9th CGPM and the CIPM formally adopted "degree Celsius" in 1948, formally keeping the recognized degree symbol, rather than adopting the gradian/centesimal degree symbol. For scientific use, "Celsius" is the term used, with "centigrade" remaining in common but decreasing use in informal contexts in English-speaking countries, it was not until February 1985 that the weather forecasts issued by
Lychee is the sole member of the genus Litchi in the soapberry family, Sapindaceae. It is a tropical tree native to the Guangdong and Fujian provinces of China, where cultivation is documented from 1059 AD. China is the main producer of lychees, followed by India, other countries in Southeast Asia, the Indian Subcontinent and South Africa. A tall evergreen tree, the lychee bears small fleshy fruits; the outside of the fruit is pink-red textured and inedible, covering sweet flesh eaten in many different dessert dishes. Lychee seeds contain methylenecyclopropylglycine which can cause hypoglycemia associated with outbreaks of encephalopathy in undernourished Indian and Vietnamese children who had consumed lychee fruit. Litchi chinensis is the sole member of the genus Litchi in Sapindaceae, it was described and named by French naturalist Pierre Sonnerat in his account "Voyage aux Indes orientales et à la Chine, fait depuis 1774 jusqu'à 1781", published in 1782. There are three subspecies, determined by flower arrangement, twig thickness and number of stamens.
Litchi chinensis subsp. Chinensis is the only commercialized lychee, it grows wild in southern China, northern Vietnam, Cambodia. It has thin twigs, flowers have six stamens, fruit are smooth or with protuberances up to 2 mm. Litchi chinensis subsp. Philippinensis Leenh, it is common in the wild in the Philippines and cultivated. It has thin twigs, six to seven stamens, long oval fruit with spiky protuberances up to 3 mm. Litchi chinensis subsp. Javensis, it is only known in Malaysia and Indonesia. It has thick twigs, flowers with seven to eleven stamens in sessile clusters, smooth fruit with protuberances up to 1 mm. Litchi chinensis is an evergreen tree, less than 15 m tall, sometimes reaching 28 m, its evergreen leaves, 5 to 8 in long, are pinnate, having 4 to 8 alternate, elliptic-oblong to lanceolate, abruptly pointed, The bark is grey-black, the branches a brownish-red. Its evergreen leaves are 12.5 to 20 cm long, with leaflets in two to four pairs. Lychee have a similar foliage to the Lauraceae family due to convergent evolution.
They are adapted by developing leaves that repel water, are called laurophyll or lauroid leaves. Flowers grow on a terminal inflorescence with many panicles on the current season's growth; the panicles grow in clusters of ten or more, reaching 10 to 40 cm or longer, holding hundreds of small white, yellow, or green flowers that are distinctively fragrant. The lychee bears fleshy fruits that mature in 80–112 days depending on climate and cultivar. Fruits vary in shape from round to ovoid to heart-shaped, up to 5 cm long and 4 cm wide, weighing 20 g; the thin, tough skin is green when immature, ripening to red or pink-red, is smooth or covered with small sharp protuberances textured. The rind is inedible but removed to expose a layer of translucent white fleshy aril with a floral smell and a fragrant, sweet flavor; the skin turns dry when left out after harvesting. The fleshy, edible portion of the fruit is an aril, surrounding one dark brown inedible seed, 1 to 3.3 cm long and 0.6 to 1.2 cm wide.
Some cultivars produce a high percentage of fruits with shriveled aborted seeds known as'chicken tongues'. These fruit have a higher price, due to having more edible flesh. Since the perfume-like flavour is lost in the process of canning, the fruit is eaten fresh. Cultivation of lychee began in the region of southern China, going back to 1059 AD, northern Vietnam. Unofficial records in China refer to lychee as far back as 2000 BC. Wild trees still grow on Hainan Island. There are many stories of the fruit's use as a delicacy in the Chinese Imperial Court, it was first described and introduced to the West in 1656 by Michal Boym, a Polish Jesuit missionary. In the 1st century, fresh lychees were in such demand at the Imperial Court that a special courier service with fast horses would bring the fresh fruit from Guangdong. There was great demand for lychee in the Song Dynasty, in his Li chi pu, it was the favourite fruit of Emperor Li Longji's favoured concubine Yang Yuhuan. The emperor had the fruit delivered at great expense to the capital.
The lychee attracted attention of European travellers, such as Juan González de Mendoza in his History of the great and mighty kingdom of China, based on the reports of Spanish friars who had visited China in the 1570s gave the fruit high praise: hey haue a kinde of plummes, that they doo call lechias, that are of an exceeding gallant tast, neuer hurteth any body, although they shoulde eate a great number of them. Lychees are extensively grown in China, Thailand and the rest of tropical Southeast Asia, the Indian Subcontinent, in South Africa, the Caribbean, Australia and the southeastern United States, they require a tropical climate, frost-free and is not below the temperature of −4 °C. Lychees require a climate with high summer heat and humidity. Growth is best on well-drained acidic soils rich in organic matter and mulch. A wide range of cultivars are available, with early and late maturing forms suited to warmer and cooler climates, respectively, they are grown as an ornamenta
National Archives and Records Administration
The National Archives and Records Administration is an independent agency of the United States government charged with preserving and documenting government and historical records and with increasing public access to those documents, which comprise the National Archives. NARA is responsible for maintaining and publishing the authentic and authoritative copies of acts of Congress, presidential directives, federal regulations; the NARA transmits votes of the Electoral College to Congress. The Archivist of the United States is the chief official overseeing the operation of the National Archives and Records Administration; the Archivist not only maintains the official documentation of the passage of amendments to the U. S. Constitution by state legislatures, but has the authority to declare when the constitutional threshold for passage has been reached, therefore when an act has become an amendment; the Office of the Federal Register publishes the Federal Register, Code of Federal Regulations, United States Statutes at Large, among others.
It administers the Electoral College. The National Historical Publications and Records Commission —the agency's grant-making arm—awards funds to state and local governments and private archives and universities, other nonprofit organizations to preserve and publish historical records. Since 1964, the NHPRC has awarded some 4,500 grants; the Office of Government Information Services is a Freedom of Information Act resource for the public and the government. Congress has charged NARA with reviewing FOIA policies and compliance of Federal agencies and to recommend changes to FOIA. NARA's mission includes resolving FOIA disputes between Federal agencies and requesters; each branch and agency of the U. S. government was responsible for maintaining its own documents, which resulted in the loss and destruction of records. Congress established the National Archives Establishment in 1934 to centralize federal record keeping, with the Archivist of the United States as chief administrator; the National Archives was incorporated with GSA in 1949.
The first Archivist, R. D. W. Connor, began serving in 1934; as a result of a first Hoover Commission recommendation, in 1949 the National Archives was placed within the newly formed General Services Administration. The Archivist served as a subordinate official to the GSA Administrator until the National Archives and Records Administration became an independent agency on April 1, 1985. In March 2006, it was revealed by the Archivist of the United States in a public hearing that a memorandum of understanding between NARA and various government agencies existed to "reclassify", i.e. withdraw from public access, certain documents in the name of national security, to do so in a manner such that researchers would not be to discover the process. An audit indicated that more than one third withdrawn since 1999 did not contain sensitive information; the program was scheduled to end in 2007. In 2010, Executive Order 13526 created the National Declassification Center to coordinate declassification practices across agencies, provide secure document services to other agencies, review records in NARA custody for declassification.
NARA's holdings are classed into "record groups" reflecting the governmental department or agency from which they originated. Records include paper documents, still pictures, motion pictures, electronic media. Archival descriptions of the permanent holdings of the federal government in the custody of NARA are stored in the National Archives Catalog; the archival descriptions include information on traditional paper holdings, electronic records, artifacts. As of December 2012, the catalog consisted of about 10 billion logical data records describing 527,000 artifacts and encompassing 81% of NARA's records. There are 922,000 digital copies of digitized materials. Most records at NARA are in the public domain, as works of the federal government are excluded from copyright protection. However, records from other sources may still be protected by donor agreements. Executive Order 13526 directs originating agencies to declassify documents if possible before shipment to NARA for long-term storage, but NARA stores some classified documents until they can be declassified.
Its Information Security Oversight Office monitors and sets policy for the U. S. government's security classification system. Many of NARA's most requested records are used for genealogy research; this includes census records from 1790 to 1940, ships' passenger lists, naturalization records. Archival Recovery Teams investigate the theft of records; the most well known facility of the National Archives and Records Administration is the National Archives Building, located north of the National Mall on Constitution Avenue in Washington, D. C.. A sister facility, known as the National Archives at College Park was opened 1994 near the University of Maryland, College Park; the Washington National Records Center located in the Washington, D. C. metropolitan area, is a large warehouse facility where federal records that are still under the control of the creating agency are stored. Federal government agencies pay a yearly fee for storage at the facility. In accordance with federal records schedules, documents at WNRC are transferred to the legal custody of the National Archives after a certain time.
Temporary records at WNRC are
A seedbed or seedling bed is the local soil environment in which seeds are planted. It comprises not only the soil but a specially prepared cold frame, hotbed or raised bed used to grow the seedlings in a controlled environment into larger young plants before transplanting them into a garden or field. A seedling bed is used to increase the number of seeds; the soil of a seedbed needs to be smoothed, without large lumps. These traits are needed so that seeds can be planted and at a specific depth for best germination. Large lumps and uneven surface would tend to make the planting depth random. Many types of seedlings need loose soil with minimal rocky content for best conditions to grow their roots. Seedbed preparation in farm fields involves secondary tillage via harrows and cultivators; this may chisel plows. No-till farming methods avoid tillage for seedbed preparation as well as weed control. Seedbed preparation in gardens involves secondary tillage via hand tools such as rakes and hoes; this may follow primary tillage by picks, or mattocks.
Rotary tillers provide a powered alternative that takes care of both secondary tillage. The preparation of a seedbed may include: The removal of debris. Insect eggs and disease spores are found in plant debris and so this is removed from the plot. Stones and larger debris will physically prevent the seedlings from growing. Levelling; the site will have been levelled for drainage. Breaking up the soil. Compacted soil will be broken up by digging; this allows air and water to enter, helps the seedling penetrate the soil. Smaller seeds require a finer soil structure; the surface the soil can be broken down into a fine granular structure using a tool such as a rake. Soil improvement; the soil structure may be improved by the introduction of organic matter such as peat. Fertilizing; the nitrate and phosphate levels of the soil can be adjusted with fertilizer. If the soil is deficient in any micro nutrients, these too can be added; the seedlings may be left to grow to adult plants in the seedbed after thinning to remove the weaker ones, or they may be moved to a border as young plants.
Category:Horticulture and gardening Open field Seed drill False seedbed Sowing Stale seed bed Stratification
A crop is a plant or animal product that can be grown and harvested extensively for profit or subsistence. Crop may refer either to the harvest in a more refined state. Most crops are cultivated in aquaculture. A crop is expanded to include macroscopic fungus, or alga. Most crops are harvested as food for humans or fodder for livestock; some crops are gathered from the wild. Important non-food crops include horticulture and industrial crops. Horticulture crops include plants used for other crops. Floriculture crops include bedding plants, flowering garden and pot plants, cut cultivated greens, cut flowers. Industrial crops are produced for biofuel, or medicine; the importance of a crop varies by region. Globally, the following crops contribute most to human food supply: rice, wheat and other sugar crops, soybean oil, other vegetables, palm oil, legume pulses, sunflowerseed oil and mustard oil, other fruits, millet, beans, sweet potatoes, various nuts, cottonseed oil, groundnut oil, yams. Note that many of the globally minor crops are regionally important.
For example in Africa, roots & tubers dominate with 421 kcal/person/day, sorghum and millet contribute 135 kcal and 90 kcal, respectively. In terms of produced weight, the following crops are the most important ones: Sleper, David A.. Breeding Field Crops. Blackwell Publishing. ISBN 9780813824284. Retrieved December 5, 2011. Media related to Crops at Wikimedia Commons
Bruges is the capital and largest city of the province of West Flanders in the Flemish Region of Belgium, in the northwest of the country. The area of the whole city amounts to more than 13,840 hectares, including 1,075 hectares off the coast, at Zeebrugge; the historic city centre is a prominent World Heritage Site of UNESCO. It is oval in about 430 hectares in size; the city's total population is 117,073. The metropolitan area, including the outer commuter zone, covers an area of 616 km2 and has a total of 255,844 inhabitants as of 1 January 2008. Along with a few other canal-based northern cities, such as Amsterdam, it is sometimes referred to as the Venice of the North. Bruges has a significant economic importance, thanks to its port, was once one of the world's chief commercial cities. Bruges is well known as the seat of the College of Europe, a university institute for European studies; the place is first mentioned in records as Bruggas, Brvccia in 840–875 as Bruciam, Brutgis uico, in portu Bruggensi, Bricge, Brycge, Bruges, Bruggas and Brugge.
The name derives from the Old Dutch for "bridge": brugga. Compare Middle Dutch brucge and modern Dutch bruggehoofd and brug; the form brugghe would be a southern Dutch variant. The Dutch word and the English "bridge" both derive from Proto-Germanic *brugjō-. Bruges was a location of coastal settlement during prehistory; this Bronze Age and Iron Age settlement is unrelated to medieval city development. In the Bruges area, the first fortifications were built after Julius Caesar's conquest of the Menapii in the first century BC, to protect the coastal area against pirates; the Franks took over the whole region from the Gallo-Romans around the 4th century and administered it as the Pagus Flandrensis. The Viking incursions of the ninth century prompted Count Baldwin I of Flanders to reinforce the Roman fortifications. Early medieval habitation starts in the 9th and 10th century on the Burgh terrain with a fortified settlement and church Bruges became important due to the tidal inlet, important to local commerce, This inlet was known as the "Golden Inlet".
Bruges received its city charter on 27 July 1128, new walls and canals were built. In 1089 Bruges became the capital of the County of Flanders. Since about 1050, gradual silting had caused the city to lose its direct access to the sea. A storm in 1134, however, re-established this access, through the creation of a natural channel at the Zwin; the new sea arm stretched all the way to Damme, a city that became the commercial outpost for Bruges. Bruges had a strategic location at the crossroads of the northern Hanseatic League trade and the southern trade routes. Bruges was included in the circuit of the Flemish and French cloth fairs at the beginning of the 13th century, but when the old system of fairs broke down the entrepreneurs of Bruges innovated, they developed, or borrowed from Italy, new forms of merchant capitalism, whereby several merchants would share the risks and profits and pool their knowledge of markets. They employed new forms of economic exchange, including letters of credit; the city eagerly welcomed foreign traders, most notably the Portuguese traders selling pepper and other spices.
With the reawakening of town life in the twelfth century, a wool market, a woollens weaving industry, the market for cloth all profited from the shelter of city walls, where surpluses could be safely accumulated under the patronage of the counts of Flanders. The city's entrepreneurs reached out to make economic colonies of England and Scotland's wool-producing districts. English contacts brought Normandy grain and Gascon wines. Hanseatic ships filled the harbor, which had to be expanded beyond Damme to Sluys to accommodate the new cog-ships. In 1277, the first merchant fleet from Genoa appeared in the port of Bruges, first of the merchant colony that made Bruges the main link to the trade of the Mediterranean; this development opened not only the trade in spices from the Levant, but advanced commercial and financial techniques and a flood of capital that soon took over the banking of Bruges. The Bourse opened in 1309 and developed into the most sophisticated money market of the Low Countries in the 14th century.
By the time Venetian galleys first appeared. Numerous foreign merchants were welcomed in Bruges, such as the Castilian wool merchants who first arrived in the 13th century. After the Castilian wool monopoly ended, the Basques, many hailing from Bilbao, thrived as merchants and established their own commercial consulate in Bruges by the mid-15th century; the foreign merchants expanded the city's trading zones. They maintained separate communities governed by their own laws until the economic collapse after 1700; such wealth gave rise to social upheavals, which were for the most part harshly contained by the militia. In 1302, after the Bruges Matins, the population joined forces with the Count of Flanders against the French, culminating in
Sterilization refers to any process that eliminates, kills, or deactivates all forms of life and other biological agents present in a specified region, such as a surface, a volume of fluid, medication, or in a compound such as biological culture media. Sterilization can be achieved through various means, including: heat, irradiation, high pressure, filtration. Sterilization is distinct from disinfection and pasteurization, in that sterilization kills, deactivates, or eliminates all forms of life and other biological agents which are present. One of the first steps toward sterilization was made by Nicolas Appert who discovered that thorough application of heat over a suitable period slowed the decay of foods and various liquids, preserving them for safe consumption for a longer time than was typical. Canning of foods has helped to reduce food borne illness. Other methods of sterilizing foods include high pressure. In general, surgical instruments and medications that enter an aseptic part of the body must be sterile.
Examples of such instruments include scalpels, hypodermic needles, artificial pacemakers. This is essential in the manufacture of parenteral pharmaceuticals. Preparation of injectable medications and intravenous solutions for fluid replacement therapy requires not only sterility but well-designed containers to prevent entry of adventitious agents after initial product sterilization. Most medical and surgical devices used in healthcare facilities are made of materials that are able to go under steam sterilization. However, since 1950, there has been an increase in medical devices and instruments made of materials that require low-temperature sterilization. Ethylene oxide gas has been used since the 1950s for heat- and moisture-sensitive medical devices. Within the past 15 years, a number of new, low-temperature sterilization systems have been developed and are being used to sterilize medical devices. Steam sterilization is the most used and the most dependable. Steam sterilization is nontoxic, inexpensive microbicidal and heats and penetrates fabrics.
There are strict international rules to protect the contamination of Solar System bodies from biological material from Earth. Standards vary depending on both the type of its destination. Many components of instruments used on spacecraft cannot withstand high temperatures, so techniques not requiring excessive temperatures are used as tolerated, including heating to at least 120 °C, chemical sterilization, oxidization and irradiation; the aim of sterilization is the reduction of present microorganisms or other potential pathogens. The degree of sterilization is expressed by multiples of the decimal reduction time, or D-value, denoting the time needed to reduce the initial number N 0 to one tenth of its original value; the number of microorganisms N after sterilization time t is given by: N N 0 = 10. The D-value is a function of sterilization conditions and varies with the type of microorganism, water activity, pH etc.. For steam sterilization the temperature, in degrees Celsius, is given as an index.
Theoretically, the likelihood of the survival of an individual microorganism is never zero. To compensate for this, the overkill method is used. Using the overkill method, sterilization is performed by sterilizing for longer than is required to kill the bioburden present on or in the item being sterilized; this provides a sterility assurance level equal to the probability of a non-sterile unit. For high-risk applications, such as medical devices and injections, a sterility assurance level of at least 10−6 is required by the United States Food and Drug Administration. A used method for heat sterilization is the autoclave, sometimes called a converter or steam sterilizer. Autoclaves use steam heated to 121–134 °C under pressure. To achieve sterility, the article is placed in a chamber and heated by injected steam until the article reaches a temperature and time setpoint. All the air is removed from the chamber, because air is undesired in the moist heat sterilization process; the article is held at the temperature setpoint for a period of time which varies depending on what bioburden is present on the article being sterilized and its resistance to steam sterilization.
A general cycle would be anywhere between 3 and 15 minutes, at 121 °C at 100 kPa, sufficient to provide a sterility assurance level of 10−4 for a product with a bioburden of 106 and a D-value of 2.0 minutes. Following sterilization, liquids in a pressurized autoclave must be cooled to avoid boiling over when the pressure is released; this may be achieved by depressurizing the sterilization chamber and allowing liqui