Terminology.

An official government translation of the Constitution of Russia in Article 5 states: "1. The Russian Federation shall consist of republics, krais, oblasts, cities of federal significance, an autonomous oblast and autonomous okrugs, which shall have equal rights as constituent entities of the Russian Federation."  Another translation of the Constitution of Russia gives for article 65: ""The Russian Federation includes the following subjects of the Russian Federation:"".  How to translate the Russian term was discussed during the 49th annual American Translators Association conference in Orlando, in which Tom Fennel, a freelance translator, argued that the term "constituent entity of the Russian Federation" should be preferred to "subject". This recommendation is also shared by Tamara Nekrasova, Head of Translation Department, Goltsblat BLP, who in her "Traps & Mishaps in Legal Translation" presentation in Paris stated that ""constituent entity of the Russian Federation" is more appropriate than "subject of the Russian Federation" (subject would be OK for a monarchy)".

Types.

Each federal subject belongs to one of the following types:

List.

a. The largest city is also listed when it is different from the capital/administrative center.  b. According to Article 13 of the Charter of Leningrad Oblast, the governing bodies of the oblast are located in the city of St. Petersburg. However, St. Petersburg is not officially named to be the administrative center of the oblast.  c. According to Article 24 of the Charter of Moscow Oblast, the governing bodies of the oblast are located in the city of Moscow and throughout the territory of Moscow Oblast. However, Moscow is not officially named to be the administrative center of the oblast.  d. Not recognized internationally as a part of Russia.  e. In February 2000, the former code of 20 for the Chechen Republic was cancelled and replaced with code 95. License plate production was suspended due to the Chechen Wars, causing numerous issues, which in turn forced the region to use a new code.

Mergers, splits and internal territorial changes.

Starting in 2005, some of the federal subjects were merged into larger territories. In this process, six very sparsely populated subjects (comprising in total 0.3% of the population of Russia) were integrated into more populated subjects, with the hope that the economic development of those territories would benefit from the much larger means of their neighbours. The was finished on 1 March 2008. No new mergers have been planned since March 2008. The six territories became "administrative-territorial regions with special status". They have large proportions of minorities, with Russians being a majority only in three of them. Four of those territories have a second official language in addition to Russian: Buryat (in two of the merged territories), Komi-Permian, Koryak. This is an exception: all the other official languages of Russia (other than Russian) are set by the Constitutions of its constituent Republics (Mordovia, Chechnya, Dagestan etc.). The status of the "administrative-territorial regions with special status" has been a subject of criticism because it does not appear in the Constitution of the Russian Federation.  In addition to those six territories that entirely ceased to be subjects of the Russian Federation and were downgraded to territories with special status, another three subjects have a status of subject but are simultaneously part of a more populated subject: With an estimated population of 49348 as of 2018, Chukotka is currently the least populated subject of Russia that is not part of a more populated subject. It was separated from Magadan Oblast in 1993. Chukotka is one of the richest subjects of Russia (with a GRP per capita equivalent to that of Australia) and therefore does not fit in the pattern of merging a subject to benefit from the economic dynamism of the neighbour.  In 1992, Ingushetia separated from Chechnya, both to stay away from the growing violence in Chechnya and as a bid to obtain the Eastern part of Northern Ossetia (it did not work: the Chechen conflict spread violence to Ingushetia, and North Ossetia retained its Prigorodny District). Those two Muslim republics, populated in vast majority (95%+) by closely related Vainakh people, speaking Vainakhish languages, remain the two poorest subjects of Russia, with the GRP per capita of Ingushetia being equivalent to that of Iraq. According to 2016 statistics, however they are also the safest regions of Russia, and also have the lowest alcohol consumption, with alcohol poisoning at least 40 times lower than the national average.  Until 1994, Sokolsky District, Nizhny Novgorod Oblast was part of Ivanovo Oblast.  In 2011–2012, the territory of Moscow increased by 140% (to 2511 km2) by acquiring part of Moscow Oblast.  On 13 May 2020, the governors of Arkhangelsk Oblast and Nenets Autonomous Okrug announced their plan to merge following the collapse of oil prices stemming from the COVID-19 pandemic. A referendum on the merger is planned to be held on 13 September 2020.

The federal subjects of Russia, also referred to as the subjects of the Russian Federation (, "subyekty Rossiyskoy Federatsii") or simply as the subjects of the federation ( "subyekty federatsii"), are the constituent entities of Russia, its top-level political divisions according to the Constitution of Russia. Since March 18, 2014, the Russian Federation constitutionally has consisted of 85 federal subjects, of which two are located on the Crimean Peninsula, which is not recognized internationally as part of Russia.


Early history.

Andrew Tridgell developed the first version of Samba Unix in December 1991 and January 1992, as a PhD student at the Australian National University, using a packet sniffer to do of the protocol used by DEC Pathworks server software. At the time of the first releases, versions 0.1, 0.5 and 1.0, all from the first half of January 1992, it did not have a proper name, and Tridgell just called it "a Unix file server for Dos Pathworks". At the time of version 1.0, he realized that he "had in fact implemented the netbios protocol" and that "this software could be used with other PC clients".  With a focus on interoperability with Microsoft's LAN Manager, Tridgell released "netbios for unix", observer, version 1.5 in December 1993. This release was the first to include client-software as well as a server. Also, at this time GPL2 was chosen as license.  Midway through the 1.5-series, the name was changed to "smbserver". However, Tridgell got a trademark notice from the company "Syntax", who sold a product named "TotalNet Advanced Server" and owned the trademark for "SMBserver". The name "Samba" was derived by running the Unix command grep through the system dictionary looking for words that contained the letters S, M, and B, in that order (i.e. ).  Versions 1.6, 1.7, 1.8, and 1.9 followed relatively quickly, with the latter being released in January 1995. Tridgell considers the adoption of CVS in May 1996 to mark the birth of the Samba Team, though there had been contributions from other people, especially Jeremy Allison, previously.  Version 2.0.0 was released in January 1999, and version 2.2.0 in April 2001.

Version history.

Version 3.0.0, released on 23 September 2003, was a major upgrade. Samba gained the ability to join Active Directory as a member, though not as a domain controller. Subsequent point-releases to 3.0 have added minor new features. Currently, the latest release in this series is 3.0.37, released 1 October 2009, and shipped on a voluntary basis. The 3.0.x series officially reached end-of-life on 5 August 2009.  Version 3.1 was used only for development.  With version 3.2, the project decided to move to time-based releases. New major releases, such as 3.3, 3.4, etc. will appear every 6 months. New features will only be added when a major release is done, point-releases will be only for bug fixes. Also, 3.2 marked a change of license from GPL2 to GPL3, with some parts released under LGPL3. The main technical change in version 3.2 was to autogenerate much of the DCE/RPC-code that used to be handcrafted. Version 3.2.0 was released on 1 July 2008. and its current release is 3.2.15 from 1 October 2009. The 3.2.x series officially reached end-of-life on 1 March 2010.

Security.

Some versions of Samba 3.6.3 and lower suffer serious security issues which can allow anonymous users to gain root access to a system from an anonymous connection, through the exploitation of an error in Samba's remote procedure call.  On 12 April 2016, Badlock, a crucial security bug in Windows and Samba, was disclosed. Badlock for Samba is referenced by (SAMR and LSA man in the middle attacks possible).  On 24 May 2017, it was announced that a remote code execution vulnerability had been found in Samba named "EternalRed" or "SambaCry", affecting all versions since 3.5.0. This vulnerability was assigned identifier.

Features.

Samba allows file and print sharing between computers running Microsoft Windows and computers running Unix. It is an implementation of dozens of services and a dozen protocols, including:  All these services and protocols are frequently incorrectly referred to as just NetBIOS or SMB. The NBT (NetBIOS over TCP/IP) and WINS protocols, and their underlying SMB version 1 protocol, are deprecated on Windows. Since Windows Vista the WS-Discovery protocol has been included along with SMB2 and its successors, which supersede these. (WS-Discovery is implemented on Unix-like platforms by third party daemons which allow Samba shares to be discovered when the deprecated protocols are disabled).  Samba sets up network shares for chosen Unix directories (including all contained subdirectories). These appear to Microsoft Windows users as normal Windows folders accessible via the network. Unix users can either mount the shares directly as part of their file structure using the mount.cifs command or, alternatively, can use a utility, smbclient (libsmb) installed with Samba to read the shares with a similar interface to a standard command line FTP program. Each directory can have different access privileges overlaid on top of the normal Unix file protections. For example: home directories would have read/write access for all known users, allowing each to access their own files. However they would still not have access to the files of others unless that permission would normally exist. Note that the netlogon share, typically distributed as a read only share from /etc/samba/netlogon, is the logon directory for user logon scripts.  Samba services are implemented as two daemons:  Samba configuration is achieved by editing a single file (typically installed as /etc/smb.conf or /etc/samba/smb.conf). Samba can also provide user logon scripts and group policy implementation through poledit.  Samba is included in most Linux distributions and is started during the boot process. On Red Hat, for instance, the /etc/rc.d/init.d/smb script runs at boot time, and starts both daemons. Samba is not included in Solaris 8, but a Solaris 8-compatible version is available from the Samba website.  Samba includes a web administration tool called "Samba Web Administration Tool" (SWAT). SWAT was removed starting with version 4.1.

Samba TNG.

Samba TNG (The Next Generation) was forked in late 1999, after disagreements between the Samba Team leaders and Luke Leighton about the directions of the Samba project. They failed to come to an agreement on a development transition path which allowed the research version of Samba he was developing (known at the time as Samba-NTDOM) to slowly be integrated into Samba. Development has been minimal, due to a lack of developers. The Samba TNG team frequently directed potential users towards Samba because of its better support and development.  A key goal of the Samba TNG project was to rewrite all of the NT Domains services as FreeDCE projects. This was made difficult as the services were developed manually through network reverse-engineering, with limited or no reference to DCE/RPC documentation.  A key difference from Samba was in the implementation of the NT Domains suite of protocols and MSRPC services. Samba makes all the NT Domains services available from a single place, whereas Samba TNG separated each service into its own program.  ReactOS started using Samba TNG services for its SMB implementation. The developers of both projects were interested in seeing the Samba TNG design used to help get ReactOS talking to Windows networks. They worked together to adapt the network code and build system. The multi-layered and modular approach made it easy to port each service to ReactOS.

Samba is a free software re-implementation of the SMB networking protocol, and was originally developed by Andrew Tridgell. Samba provides file and print services for various Microsoft Windows clients and can integrate with a Microsoft Windows Server domain, either as a Domain Controller (DC) or as a domain member. As of version 4, it supports Active Directory and Microsoft Windows NT domains.


Names.

Ulan-Ude was first called Udinskoye () for its location on the Uda River. It was founded as a small fort in 1668. From around 1735, the settlement was called Udinsk () and was granted town status under that name in 1775. The name was changed to Verkhneudinsk, literally "Upper Udinsk" () in 1783, to differentiate it from Nizhneudinsk ("Lower Udinsk") lying on a different Uda River near Irkutsk which was granted town status that year.  The "upper" and "lower" refer to positions of the two cities relative to each other, not the location of the cities on their respective Uda rivers. Verkhneudinsk lies at the mouth of its Uda, i.e. the lower end, while Nizhneudinsk is along the middle stretch of its Uda. The current name was given to the city 27 July 1934 and means "red Uda" in Buryat, reflecting the Soviet Union's Communist ideology.

Geography.

Ulan-Ude lies east of Moscow and southeast of Lake Baikal. It is above sea level at the foot of the Khamar-Daban and Ulan-Burgas mountain ranges, next to the confluence of the Selenga River and its tributary, the Uda, which divides the city.

Hydrography.

Ulan-Ude is traversed by two rivers, the Selenga and Uda. The Selenga provides the greatest inflow to Baikal Lake, supplying 50% of all rivers in its basin. The Selenga brings into the lake about of water per year, exerting a major influence on the formation of the lake water and its sanitary condition. Selenga is the habitat of the most valuable fish species such as Omul, Siberian sturgeon, Siberian taimen, Thymallus and Coregonus.  Uda is the right inflow of the Selenga river. The length of the watercourse is.

History.

The first occupants of the area where Ulan-Ude now stands were the Evenks and, later, the Buryat Mongols. Ulan-Ude was settled in 1666 by the Russian Cossacks as the fortress of Udinskoye. Due to its favorable geographical position, it grew rapidly and became a large trade center which connected Russia with China and Mongolia and, from 1690, was the administrative center of the Transbaikal region.  By 1775, it was known as Udinsk, and in 1783 it was granted city status and renamed Verkhneudinsk. After a large fire in 1878, the city was almost completely rebuilt. The Trans-Siberian Railway reached the city in 1900 causing an explosion in growth. The population which was 3,500 in 1880 reached 126,000 in 1939.  From 6 April to October 1920 Verkhneudinsk was the capital of the Far Eastern Republic (Дальневосточная Республика), sometimes called Chita Republic. It was a nominally independent state that existed from April 1920 to November 1922 in the easternmost part of the Russian Far East. On 27 July 1934, the city was renamed Ulan-Ude. There was a War there between Reds and Whites in 1917–1924.

Administrative and municipal status.

Ulan-Ude is the capital of the republic. Within the framework of administrative divisions, it is incorporated as the city of republic significance of Ulan-Ude—an administrative unit with the status equal to that of the districts. As a municipal division, the city of republic significance of Ulan-Ude is incorporated as Ulan-Ude Urban Okrug.

Demographics.

According to the 2010 Census, 404,426 people lived in Ulan-Ude; up from 359,391 recorded in the 2002 Census. In terms of population, it is the third-largest city in eastern Siberia. The ethnic makeup of the city's population in 2010:  The city is the center of Tibetan Buddhism in Russia and the important Ivolginsky datsan is located from the city.

Transportation.

Ulan-Ude is located on the main line (Trans-Siberian line) of the Trans-Siberian Railway between Irkutsk and Chita at the junction of the Trans-Mongolian line (the Trans-Mongolian Railway) which begins at Ulan Ude and continues south through Mongolia to Beijing in China.  The city also lies on the M55 section of the Baikal Highway (part of the Trans-Siberian Highway), the main federal road to Vladivostok. Air traffic is served by the Ulan-Ude Airport (Baikal), as well as the smaller Ulan-Ude Vostochny Airport. Intracity transport includes tram, bus, and "marshrutka" (share taxi) lines.

Culture.

Until 1991, Ulan-Ude was closed to foreigners. There are old merchants' mansions richly decorated with wood and stone carving in the historical center of Ulan-Ude, along the river banks which are exceptional examples of Russian classicism. The city has a large ethnographic museum which recalls the history of the peoples of the region. There is a large and highly unusual statue of the head of Vladimir Lenin in the central square: the largest in the world. Built in 1970 for the centennial of Lenin's birth, it towers over the main plaza at and weighs 42 tons.

Sights.

The "Ethnographic Museum of the peoples of Transbaikal" is one of Russia's largest open-air museums. The museum contains historical finds from the era of the Slab Grave Culture and the Xiongnu until the mid 20th century, including a unique collection of samples of wooden architecture of Siberia – more than forty architectural monuments.  Odigitrievsky Cathedral – Orthodox Church Diocese of the Buryat, was the first stone building in the city and is a Siberian baroque architectural monument. The cathedral is considered unique because it is built in a zone of high seismic activity in the heart of the city on the banks of the River Uda River where it flows into the Selenga.  One of the attractions of Ulan-Ude is a monument in the town square — the square of the Soviets — in the form of the head of Lenin (sculptors G.V. Neroda, J.G. Neroda, architects Dushkin, P.G. Zilberman). The monument, weighing 42 tons and with a height of, was opened in 1971 in honor of the centenary of Lenin's birth. The Voice of Nomads international music and culture festival is held annually at various sites in the city.

Climate.

Ulan-Ude can be described as possessing a humid steppe climate (Köppen climate classification "BSk"), bordering on a humid continental climate ("Dwb" borders on "Dwc"). The climate is characterised by long, dry, cold winters and short but very warm summers. Precipitation is low and heavily concentrated in the warmer months.  Vladimir Popov, musician and backup singer for Leonid and Friends

Twin towns - sister cities.

Ulan-Ude is twinned with:

Ulan-Ude (, "Ulaan-Üde", ; ;, "Ulaan-Üd", ) is the capital city of the Republic of Buryatia, Russia; it is located about southeast of Lake Baikal on the Uda River at its confluence with the Selenga. According to the 2010 Census, 404,426 people lived in Ulan-Ude; up from 359,391 recorded in the 2002 Census, making the city the third-largest in the Russian Far East by population.


History.

First usage of name.

The marque dates back to 1898 when a car made by Automobilwerk Eisenach was named the Wartburgwagen. It consisted of a two-seating cane chair, four mudguards, two headlamps, and a two-cylinder, 765-cc engine. Its top speed was. The name was dropped in 1904 when the company changed hands but re-appeared briefly in the early 1930s on the BMW 3/15 DA-3 Wartburg, which was BMW's first sports car.

Main usage of name.

The name was revived in 1956 by VEB Automobilwerk Eisenach and given to an updated version of their IFA F9 car which had been in production since 1950. The new car had a more powerful version of the three-cylinder two-stroke engine driving the front wheels and a completely new body. By this time, Germany had been divided into two countries (the West and the East) and the Wartburg factory was in the communist East (GDR).  Exports to West Germany began in 1958, and by the early 1960s the car was exported to other countries, including the United Kingdom and United States. Right hand drive models were first manufactured in 1963 and exported to Cyprus, with British buyers being introduced to the car in 1964. However, just 550 examples (450 saloons and 100 estates) were sold in the UK. These were two-tone models sold at the same price as a basic British Mini, appealing mostly to older people.  The 311 model was manufactured in a number of variations, including pickup, estate, and two-seater roadster. A convertible was advertised in the GDR in 1957 but its production never exceeded 350 units.  The engine was enlarged to 992 cc in 1962 and a completely new body was manufactured after 1966. This version, the 353, was sold as the Wartburg Knight in several countries, including the UK, where the estate model was sold as the Tourist. It remained on sale until 1976, by which time nearly 20,000 had been sold. This marked the end of right-hand drive Wartburgs, but left-hand drive versions continued to be imported to the UK and at least one model was converted to right-hand drive.  Also, in 1966, the gearbox gained synchromesh on all speeds and was designed to freewheel as a fuel efficiency and engine protection measure, which meant that unless the freewheel feature was disabled by a lever beneath the steering column, the car did not benefit from engine braking. Because the engine was a two stroke unit, it relied on the passage of the petrol mixture (two-stroke oil and petrol, at a ratio of 1:50) to lubricate the engine. With the freewheel device disengaged, the engine could be starved of lubricant and seize on long down-hill runs unless the throttle was opened briefly from time to time. Nevertheless, disengaging the freewheel device was recommended to give engine braking in snowy or icy conditions.  There are four editions of Wartburg 353:  There are three models of Wartburg 353 - Limousine (sedan), Tourist (combi) and Trans (pickup). The 353W modification had a new, round-shaped dashboard and black-coloured grille. It was also fitted with disc brakes on the front axle. The 353S modification featured new rectangular headlights integrated into the grille of a new shape. In the De Luxe version you can see electronic ignition, 5-speed gearbox, front and back fog lights, alarm system and central lock door. Usually this model can reach around 150-155 km/h. Moreover, the radiator was moved from behind the engine (353, 353W) to the classic position behind the grille.  The engine of the car was with (depending on the year of production and the carburettor type). Fuel economy was barely acceptable for run-about driving. The offer of Volkswagen to move a surplus engine assembly line to the GDR, to be paid off by manufacture, was accepted by the government on account of fuel economy. In 1988, the new model Wartburg 1.3 therefore replaced the old model 353S, featuring the reliable though bulky 4-stroke engine from the Volkswagen Golf. Being larger than the compact 2-stroke unit, this needed considerable reconstruction of the engine compartment.

Demise.

The VW engine gave 64 horsepower. The new Wartburg was short-lived, its end being sealed by German reunification; production was inefficient and could not compete with West-German manufacturers. Production ended in April 1991, and the factory was acquired by Opel.  There are still some cars in a road worthy condition, and Wartburg owners' clubs exist throughout Europe. Some Wartburgs are still used as rally racing cars.

Derivatives.

The Melkus RS 1000 used a mid-mounted three-cylinder two-stroke engine from the Wartburg 353.

The Wartburg was a car marque known for its East German manufactured models, but has its origins dating to 1898. The name derives from Wartburg Castle on one of the hills overlooking the town of Eisenach where the cars were made. From the 1950s, Wartburgs were a three-cylinder two-stroke engine with only seven major moving parts (three pistons, three connecting rods and one crankshaft). Production ended in April 1991, and the factory was acquired by Opel.


Early life.

Tieck was born in Berlin, the son of a rope-maker. His siblings were the sculptor Christian Friedrich Tieck and the poet Sophie Tieck. He was educated at the, where he learned Greek and Latin, as required in most preparatory schools. He also began learning Italian at a very young age, from a grenadier with whom he became acquainted. Through this friendship, Tieck was given a first-hand look at the poor, which could be linked to his work as a Romanticist. He later attended the universities of Halle, Göttingen, and Erlangen. At Göttingen, he studied Shakespeare and Elizabethan drama.  On returning to Berlin in 1794, Tieck attempted to make a living by writing. He contributed a number of short stories (1795–98) to the series "Straussfedern", published by the bookseller C. F. Nicolai and originally edited by J. K. A. Musäus. He also wrote "Abdallah" (1796) and a novel in letters, "William Lovell" (3 vols, 1795–96).

Adoption of Romanticism.

Tieck's transition to Romanticism is seen in the series of plays and stories published under the title "Volksmärchen von Peter Lebrecht" (3 vols., 1797), a collection containing the fairy tale "Der blonde Eckbert", which blends exploration of the paranoiac mind with the realm of the supernatural, and a witty dramatic satire on Berlin literary taste, "Der gestiefelte Kater". With his school and college friend Wilhelm Heinrich Wackenroder (1773–1798), he planned the novel "Franz Sternbalds Wanderungen" (vols. i–ii. 1798), which with Wackenroder's "Herzensergiessungen" (1796), was the first expression of the Romantic enthusiasm for old German art.  In 1798 Tieck married and in the following year settled in Jena, where he, the two brothers August and Friedrich Schlegel, and Novalis were the leaders of the early Romantic school (also known as Jena Romanticism). His writings between 1798 and 1804 include the satirical drama, "Prinz Zerbino" (1799), and "Romantische Dichtungen" (2 vols., 1799–1800). The latter contains Tieck's most ambitious dramatic poems, "Leben und Tod der heiligen Genoveva", "Leben und Tod des kleinen Rotkäppchens", which were followed in 1804 by the "comedy" in two parts, "Kaiser Oktavianus". These dramas are typical plays of the first Romantic school. Although formless and destitute of dramatic qualities, they show the influence of both Calderón and Shakespeare. "Kaiser Oktavianus" is a poetic glorification of the Middle Ages.  In 1801 Tieck went to Dresden, then lived for a time at Ziebingen near Frankfurt, and spent many months in Italy. In 1803 he published a translation of "Minnelieder aus der schwäbischen Vorzeit", then between 1799 and 1804 an excellent version of "Don Quixote", and in 1811 two volumes of Elizabethan dramas, "Altenglisches Theater". From 1812 to 1817 he collected in three volumes a number of his earlier stories and dramas, under the title "Phantasus". In this collection appeared the stories "Der Runenberg", "Die Elfen", "Der Pokal", and the dramatic fairy tale "Fortunat".  In 1817 Tieck visited England in order to collect materials for a work on Shakespeare, which was never finished. In 1819 he settled permanently in Dresden, and from 1825 he was literary adviser to the Court Theatre. His semi-public readings from the dramatic poets gave him a reputation which extended far beyond the capital of the Kingdom of Saxony. The new series of short stories which he began to publish in 1822 also won him a wide popularity. Notable among these are "Die Gemälde", "Die Reisenden", "Die Verlobung", and "Des Lebens Überfluss".  More ambitious and on a wider canvas are the historical or semi-historical novels "Dichterleben" (1826), "Der Aufruhr in den Cevennen" (1826, unfinished), and "Der Tod des Dichters" (1834). "Der junge Tischlermeister" (1836; but begun in 1811) is a work written under the influence of Goethe's "Wilhelm Meister". His story of "Vittoria Accorombona" (1840) was written in the style of the French Romanticists and shows a falling-off.

Later years.

In later years Tieck carried on a varied literary activity as a critic ("Dramaturgische Blätter", 2 vols., 1825–1826; "Kritische Schriften", 2 vols., 1848). He also edited the translation of Shakespeare by August Wilhelm Schlegel, who was assisted by Tieck's daughter Dorothea (1790–1841) and by Wolf Heinrich, Graf von Baudissin (1789–1878); "Shakespeares Vorschule" (2 vols., 1823–1829); and the works of Heinrich von Kleist (1826) and of Jakob Michael Reinhold Lenz (1828). In 1841 Friedrich Wilhelm IV of Prussia invited Tieck to Berlin, where he received a pension for his remaining years. He died in Berlin on 28 April 1853.

Literary significance.

Tieck's importance lay in the readiness with which he adapted himself to the emerging new ideas which arose at the close of the 18th century, as well as his Romantic works, such as "Der blonde Eckbert". His importance in German poetry, however, is restricted to his early period. In later years it was as the helpful friend and adviser of others, or as the well-read critic of wide sympathies, that Tieck distinguished himself.  Tieck also influenced Richard Wagner's "Tannhäuser". It was from "Phantasus" that Wagner based the idea of Tannhäuser going to see the Pope and of Elisabeth dying in the song battle.

Works.

Tieck's "Schriften" appeared in twenty volumes (1828–1846), and his "Gesammelte Novellen" in twelve (1852–1854). "Nachgelassene Schriften" were published in two volumes in 1855. There are several editions of "Ausgewählte Werke" by H. Welti (8 vols., 1886–1888); by J. Minor (in Kirschner's "Deutsche Nationalliteratur", 144, 2 vols., 1885); by G. Klee (with an excellent biography, 3 vols., 1892), and G. Witkowski (4 vols., 1903) and Marianne Thalmann (4 vols., 1963–66).

Translations.

"The Elves" and "The Goblet" were translated by Thomas Carlyle in "German Romance" (1827), "The Pictures" and "The Betrothal" by Bishop Thirlwall (1825). A translation of "Vittoria Accorombona" was published in 1845. A translation of "Des Lebens Überfluss" ("Life's Luxuries", by E. N. Bennett) appeared in "German Short Stories" in the Oxford University Press "World's Classics" series in 1934, but the wit of the original comes over more strongly in "The Superfluities of Life. A Tale Abridged from Tieck," which appeared anonymously in "Blackwood's Edinburgh Magazine" in February 1845. "The Journey into the Blue Distance" ("Das Alte Buch: oder Reise ins Blaue hinein", 1834). "The Romance of Little Red Riding Hood" (1801) was translated by Jack Zipes and included in his book "The Trials and Tribulations of Little Red Riding Hood."

Influences.

Tieck's biggest influence was 16th-century Italian poet Torquato Tasso, who is featured in Tieck's novel, "Vittoria Accorombona", as a secondary character.

Letters.

Tieck's Letters have been published at various locations:

Johann Ludwig Tieck (; ; 31 May 1773 – 28 April 1853) was a German poet, fiction writer, translator, and critic. He was one of the founding fathers of the Romantic movement in the late 18th and early 19th centuries.


Attributes.

UDP is a simple message-oriented transport layer protocol that is documented in. Although UDP provides integrity verification (via checksum) of the header and payload, it provides no guarantees to the upper layer protocol for message delivery and the UDP layer retains no state of UDP messages once sent. For this reason, UDP sometimes is referred to as "Unreliable Datagram Protocol". If transmission reliability is desired, it must be implemented in the user's application.  A number of UDP's attributes make it especially suited for certain applications.

Ports.

Applications can use datagram sockets to establish host-to-host communications. An application binds a socket to its endpoint of data transmission, which is a combination of an IP address and a port. In this way, UDP provides application multiplexing. A port is a software structure that is identified by the port number, a 16 bit integer value, allowing for port numbers between 0 and 65535. Port 0 is reserved, but is a permissible source port value if the sending process does not expect messages in response.  The Internet Assigned Numbers Authority (IANA) has divided port numbers into three ranges. Port numbers 0 through 1023 are used for common, well-known services. On Unix-like operating systems, using one of these ports requires superuser operating permission. Port numbers 1024 through 49151 are the registered ports used for IANA-registered services. Ports 49152 through 65535 are dynamic ports that are not officially designated for any specific service, and may be used for any purpose. These may also be used as ephemeral ports, which software running on the host may use to dynamically create communications endpoints as needed.

UDP datagram structure.

A UDP datagram consists of a datagram "header" and a "data" section. The UDP datagram header consists of 4 fields, each of which is 2 bytes (16 bits). The data section follows the header and is the payload data carried for the application.  The use of the "checksum" and "source port" fields is optional in IPv4 (pink background in table). In IPv6 only the "source port" field is optional.

Checksum computation.

The method used to compute the checksum is defined in : In other words, all 16-bit words are summed using one's complement arithmetic. Add the 16-bit values up. On each addition, if a carry-out (17th bit) is produced, swing that 17th carry bit around and add it to the least significant bit of the running total. Finally, the sum is then one's complemented to yield the value of the UDP checksum field.  If the checksum calculation results in the value zero (all 16 bits 0) it should be sent as the one's complement (all 1s) as a zero-value checksum indicates no checksum has been calculated. In this case, any specific processing is not required at the receiver, because all 0s and all 1s are equal to zero in 1's complement arithmetic.  The difference between IPv4 and IPv6 is in the pseudo header used to compute the checksum and the checksum is not optional in IPv6.

IPv4 pseudo header.

When UDP runs over IPv4, the checksum is computed using a "pseudo header" that contains some of the same information from the real IPv4 header. The pseudo header is not the real IPv4 header used to send an IP packet, it is used only for the checksum calculation.  The source and destination addresses are those in the IPv4 header. The protocol is that for UDP (see List of IP protocol numbers): 17 (0x11). The UDP length field is the length of the UDP header and data. The field data stands for the transmitted data.  UDP checksum computation is optional for IPv4. If a checksum is not used it should be set to the value zero.

IPv6 pseudo header.

When UDP runs over IPv6, the checksum is mandatory. The method used to compute it is changed as documented in : When computing the checksum, again a pseudo header is used that mimics the real IPv6 header:  The source address is the one in the IPv6 header. The destination address is the final destination; if the IPv6 packet does not contain a Routing header, that will be the destination address in the IPv6 header; otherwise, at the originating node, it will be the address in the last element of the Routing header, and, at the receiving node, it will be the destination address in the IPv6 header. The value of the Next Header field is the protocol value for UDP: 17. The UDP length field is the length of the UDP header and data.

Reliability and congestion control solutions.

Lacking reliability, UDP applications must be willing to accept some packet loss, reordering, errors or duplication. If using UDP, the end user applications must provide any necessary handshaking such as real time confirmation that the message has been received. Applications, such as TFTP, may add rudimentary reliability mechanisms into the application layer as needed. If an application requires a high degree of reliability, a protocol such as the Transmission Control Protocol may be used instead.  Most often, UDP applications do not employ reliability mechanisms and may even be hindered by them. Streaming media, real-time multiplayer games and voice over IP (VoIP) are examples of applications that often use UDP. In these particular applications, loss of packets is not usually a fatal problem. In VoIP, for example, latency and jitter are the primary concerns. The use of TCP would cause jitter if any packets were lost as TCP does not provide subsequent data to the application while it is requesting re-sending of the missing data.

Applications.

Numerous key Internet applications use UDP, including: the Domain Name System (DNS), where queries must be fast and only consist of a single request followed by a single reply packet, the Simple Network Management Protocol (SNMP), the Routing Information Protocol (RIP) and the Dynamic Host Configuration Protocol (DHCP).  Voice and video traffic is generally transmitted using UDP. Real-time video and audio streaming protocols are designed to handle occasional lost packets, so only slight degradation in quality occurs, rather than large delays if lost packets were retransmitted. Because both TCP and UDP run over the same network, many businesses are finding that a recent increase in UDP traffic from these real-time applications is hindering the performance of applications using TCP, such as point of sale, accounting, and database systems. When TCP detects packet loss, it will throttle back its data rate usage. Since both real-time and business applications are important to businesses, developing quality of service solutions is seen as crucial by some.  Some VPN systems such as OpenVPN may use UDP and perform error checking at the application level while implementing reliable connections.

Comparison of UDP and TCP.

Transmission Control Protocol is a connection-oriented protocol and requires handshaking to set up end-to-end communications. Once a connection is set up, user data may be sent bi-directionally over the connection.  User Datagram Protocol is a simpler message-based connectionless protocol. Connectionless protocols do not set up a dedicated end-to-end connection. Communication is achieved by transmitting information in one direction from source to destination without verifying the readiness or state of the receiver.

In computer networking, the User Datagram Protocol (UDP) is one of the core members of the Internet protocol suite. The protocol was designed by David P. Reed in 1980 and formally defined in. With UDP, computer applications can send messages, in this case referred to as "datagrams", to other hosts on an Internet Protocol (IP) network. Prior communications are not required in order to set up communication channels or data paths.


Early life.

Alfred Brehm was brought up in the small Thuringian village Unterrenthendorf as the son of the minister Christian Ludwig Brehm and his second wife Bertha. Christian Ludwig Brehm made a name for himself as an ornithologist by publications and an extensive collection of stuffed birds. The collection, held in the parsonage and consisting of over 9,000 dead birds, offered a glimpse into the world of European birds. His father's research gave Brehm an interest in zoology, but at first he wanted to become an architect. In the spring of 1844 he began to study with a builder in Altenburg. He continued his studies there until September 1846, when he left for Dresden in order to study architecture; however, he stopped after two semesters because Johann Wilhelm von Müller, a well-known ornithologist, was looking for a companion for an African expedition. Brehm joined the expedition on 31 May 1847 as a secretary and assistant to von Müller. The expedition took him to Egypt, the Sudan, and the Sinai Peninsula; the discoveries made were so important that, at age 20, he was made a member of the German Academy of Natural Scientists Leopoldina.

Career.

After his return, in 1853 he started to study natural sciences at the University of Jena. Like his brother Reinhold, he became active with the student corps Saxonia Jena; because of his expedition to North Africa, he received the nickname Pharaoh from his corps brothers. He graduated after four semesters in 1855 and in 1856 went on a two-year journey to Spain with his brother Reinhold. Afterwards he settled down in Leipzig as a freelance writer and wrote many scientific popularizations for Die Gartenlaube and other magazines. Apart from this, he undertook an expedition to Norway and Lapland in 1860.  In May 1861 Brehm married his cousin Mathilde Reiz, with whom he had five children. Since he wanted to travel, in 1862 he accepted the invitation of Duke Ernst II of Saxe-Coburg-Gotha to accompany him on a trip to Abyssinia. Afterwards, Brehm travelled to Africa as well as to Scandinavia and Siberia. His essays and expedition reports from the animal world were well received by the educated bourgeoisie; because of this, he was commissioned by the editor of the Bibliographisches Institut, Herrmann Julius Meyer, to write a large multivolume work on the animal world. This book became known worldwide as "Brehms Tierleben" (or, in English, "Brehm's Life of Animals"). Although Brehm's ethology is no longer seen as correct in all details, the title of his work is still a catchphrase.  Brehm's life was full with writing, scientific expeditions and lecture tours. Despite this, in 1862, he accepted the post of first director of the Zoological Garden of Hamburg and kept this position until 1867. Afterwards he went to Berlin, where he opened an aquarium. He remained with the aquarium until 1874. In the winter of 1883 to 1884 Brehm planned a lecture tour to the US. Shortly before his departure, his four children contracted diphtheria. Since he could not afford to break his contract, Brehm, a widower since 1878, went ahead with his tour. At the end of January he received word of his youngest son's death. After the hardship of this news Brehm relapsed into malaria, which he had caught in Africa in his expedition days. On 11 May 1884, he came back to Berlin. In order to find peace, he returned in July to his home town of Renthendorf, where he died on 11 November 1884. Today, the Brehm Memorial Museum is located there.

Alfred Edmund Brehm () (2 February 1829 in Unterrenthendorf, now called Renthendorf – 11 November 1884 in Renthendorf) was a German zoologist, writer, director of zoological gardens and the son of Christian Ludwig Brehm, a famous pastor and ornithologist.


Etymology.

The word "marble" derives from the Ancient Greek (), from (), "crystalline rock, shining stone", perhaps from the verb (), "to flash, sparkle, gleam"; R. S. P. Beekes has suggested that a "Pre-Greek origin is probable". This stem is also the ancestor of the English word "marmoreal", meaning "marble-like." While the English term "marble" resembles the French, most other European languages (with words like "marmoreal") more closely resemble the original Ancient Greek.

Physical origins.

Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite rock. Metamorphism causes variable recrystallization of the original carbonate mineral grains. The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the original carbonate rock (protolith) have typically been modified or destroyed.  Pure white marble is the result of metamorphism of a very pure (silicate-poor) limestone or dolomite protolith. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Green coloration is often due to serpentine resulting from originally magnesium-rich limestone or dolomite with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism.

Types.

Examples of historically notable marble varieties and locations:

Uses.

Sculpture.

White marble has been prized for its use in sculptures since classical times. This preference has to do with its softness, which made it easier to carve, relative isotropy and homogeneity, and a relative resistance to shattering. Also, the low index of refraction of calcite allows light to penetrate several millimeters into the stone before being scattered out, resulting in the characteristic waxy look which brings a lifelike luster to marble sculptures of any kind, which is why many sculptors preferred and still prefer marble for sculpting.

Construction marble.

Construction marble is a stone which is composed of calcite, dolomite or serpentine that is capable of taking a polish. More generally in construction, specifically the dimension stone trade, the term "marble" is used for any crystalline calcitic rock (and some non-calcitic rocks) useful as building stone. For example, Tennessee marble is really a dense granular fossiliferous gray to pink to maroon Ordovician limestone, that geologists call the Holston Formation.  Ashgabat, the capital city of Turkmenistan, was recorded in the 2013 "Guinness Book of Records" as having the world's highest concentration of white marble buildings.

Production.

According to the United States Geological Survey, U.S. domestic marble production in 2006 was 46,400 tons valued at about $18.1 million, compared to 72,300 tons valued at $18.9 million in 2005. Crushed marble production (for aggregate and industrial uses) in 2006 was 11.8 million tons valued at $116 million, of which 6.5 million tons was finely ground calcium carbonate and the rest was construction aggregate. For comparison, 2005 crushed marble production was 7.76 million tons valued at $58.7 million, of which 4.8 million tons was finely ground calcium carbonate and the rest was construction aggregate. U.S. dimension marble demand is about 1.3 million tons. The DSAN World Demand for (finished) Marble Index has shown a growth of 12% annually for the 2000–2006 period, compared to 10.5% annually for the 2000–2005 period. The largest dimension marble application is tile.  In 1998, marble production was dominated by 4 countries that accounted for almost half of world production of marble and decorative stone. Italy and China were the world leaders, each representing 16% of world production, while Spain and India produced 9% and 8%, respectively.  In 2018 Turkey was the world leader in marble export, with 42% share in global marble trade, followed by Italy with 18% and Greece with 10%. The largest importer of marble in 2018 was China with a 64% market share, followed by India with 11% and Italy with 5%.

Occupational safety.

Dust produced by cutting marble could cause lung disease but more research needs to be carried out on whether dust filters and other safety products reduce this risk.  In the United States, the Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for marble exposure in the workplace as 15 mg/m total exposure and 5 mg/m respiratory exposure over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 10 mg/m total exposure and 5 mg/m respiratory exposure over an 8-hour workday.

Degradation by acids.

Acids damage marble, because the calcium carbonate in marble reacts with them, releasing carbon dioxide (technically speaking, carbonic acid, but that disintegrates quickly to CO and HO) :  Thus, vinegar or other acidic solutions should never be used on marble. Likewise, outdoor marble statues, gravestones, or other marble structures are damaged by acid rain.

Microbial degradation.

The haloalkaliphilic methylotrophic bacterium "Methylophaga murata" was isolated from deteriorating marble in the Kremlin. Bacterial and fungal degradation was detected in four samples of marble from Milan cathedral; black "Cladosporium" attacked dried acrylic resin using melanin.

Cultural associations.

As the favorite medium for Greek and Roman sculptors and architects (see classical sculpture), marble has become a cultural symbol of tradition and refined taste. Its extremely varied and colorful patterns make it a favorite decorative material, and it is often imitated in background patterns for computer displays, etc.  Places named after the stone include Marblehead, Massachusetts; Marblehead, Ohio; Marble Arch, London; the Sea of Marmara; India's Marble Rocks; and the towns of Marble, Minnesota; Marble, Colorado; Marble Falls, Texas, and Marble Hill, Manhattan, New York. The Elgin Marbles are marble sculptures from the Parthenon in Athens that are on display in the British Museum. They were brought to Britain by the Earl of Elgin.

Artificial marble.

Marble dust is combined with cement or synthetic resins to make "reconstituted" or "cultured marble". The appearance of marble can be simulated with faux marbling, a painting technique that imitates the stone's color patterns.

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated, although there are exceptions. In geology, the term "marble" refers to metamorphosed limestone, but its use in stonemasonry more broadly encompasses unmetamorphosed limestone. Marble is commonly used for sculpture and as a building material.


Overview.

Computer graphics studies the manipulation of visual and geometric information using computational techniques. It focuses on the "mathematical" and "computational" foundations of image generation and processing rather than purely aesthetic issues. Computer graphics is often differentiated from the field of visualization, although the two fields have many similarities.  Connected studies include:  Applications of computer graphics include:

History.

There are several international conferences and journals where the most significant results in computer graphics are published. Among them are the SIGGRAPH and Eurographics conferences and the Association for Computing Machinery (ACM) Transactions on Graphics journal. The joint Eurographics and ACM SIGGRAPH symposium series features the major venues for the more specialized sub-fields: Symposium on Geometry Processing, Symposium on Rendering, Symposium on Computer Animation, and High Performance Graphics.  As in the rest of computer science, conference publications in computer graphics are generally more significant than journal publications (and subsequently have lower acceptance rates).

Subfields.

A broad classification of major subfields in computer graphics might be:

Geometry.

The subfield of geometry studies the representation of three-dimensional objects in a discrete digital setting. Because the appearance of an object depends largely on its exterior, boundary representations are most commonly used. Two dimensional surfaces are a good representation for most objects, though they may be non-manifold. Since surfaces are not finite, discrete digital approximations are used. Polygonal meshes (and to a lesser extent subdivision surfaces) are by far the most common representation, although point-based representations have become more popular recently (see for instance the Symposium on Point-Based Graphics). These representations are "Lagrangian," meaning the spatial locations of the samples are independent. Recently, "Eulerian" surface descriptions (i.e., where spatial samples are fixed) such as level sets have been developed into a useful representation for deforming surfaces which undergo many topological changes (with fluids being the most notable example).

Animation.

The subfield of animation studies descriptions for surfaces (and other phenomena) that move or deform over time. Historically, most work in this field has focused on parametric and data-driven models, but recently physical simulation has become more popular as computers have become more powerful computationally.

Rendering.

Rendering generates images from a model. Rendering may simulate light transport to create realistic images or it may create images that have a particular artistic style in non-photorealistic rendering. The two basic operations in realistic rendering are transport (how much light passes from one place to another) and scattering (how surfaces interact with light). See Rendering (computer graphics) for more information.  Transport describes how illumination in a scene gets from one place to another. Visibility is a major component of light transport.  Models of "scattering" and "shading" are used to describe the appearance of a surface. In graphics these problems are often studied within the context of rendering since they can substantially affect the design of rendering algorithms. Shading can be broken down into two orthogonal issues, which are often studied independently:  The former problem refers to scattering, i.e., the relationship between incoming and outgoing illumination at a given point. Descriptions of scattering are usually given in terms of a bidirectional scattering distribution function or BSDF. The latter issue addresses how different types of scattering are distributed across the surface (i.e., which scattering function applies where). Descriptions of this kind are typically expressed with a program called a shader. (Note that there is some confusion since the word "shader" is sometimes used for programs that describe local "geometric" variation.)

External links.

Industry.

Industrial labs doing "blue sky" graphics research include:  Major film studios notable for graphics research include:

Computer graphics is a sub-field of computer science which studies methods for digitally synthesizing and manipulating visual content. Although the term often refers to the study of three-dimensional computer graphics, it also encompasses two-dimensional graphics and image processing.


Origins of the friars.

What is called the mendicant movement in Church history arose primarily in the 13th century in Western Europe. Until that time the monks of Europe worked at their trade in their monastery. Renouncing personal property, they owned all things in common as a community after the example of chapters 2 and 4 of the Acts of the Apostles.  With the rise of Western monasticism, monasteries attracted not only individuals aspiring to become monks and nuns, but also property, buildings and hence riches. In the view of some, the idea that Christ came down to earth poor and that the true Church must be the church of the poor clashed with this phenomenon. The desire for true Christian authenticity was thus seen by some to contrast to the empirical reality of the Church.  The twelfth century saw great changes in western Europe. As commerce revived, urban centers arose and with them an urban middle class. New directions in spirituality were called for. Church reform became a major theme of the cultural revival of this era. In response to this, there emerged the new mendicant orders founded by Francis of Assisi (c. 1181–1226) and Dominic Guzman (c. 1170–1221).  The mendicant friars were bound by a vow of poverty and dedicated to an ascetic way of life, renouncing property and travelling the world to preach. Their survival was dependent upon the good will and material support of their listeners. It was this way of life that gave them their name, "mendicant", derived from the Latin "mendicare", meaning "to beg".  The mendicant movement had started in France and Italy and became popular in the poorer towns and cities of Europe at the beginning of the thirteenth century. The refusal of the mendicants to own property—and therefore to pay taxes—was seen as threatening the stability of the established Church which was then planning a crusade, to be financed by tithes. For this and other reasons some mendicant orders were officially suppressed by Pope Gregory X at the Second Council of Lyon in 1274 and others were reformed, so as to be capable of contributing funds or men to support the war effort.

Dominicans.

While on a visit to southern France, Saint Dominic met the Albigensians, a religious sect which had a great popularity partly because of the economic situation of the times. Dominic, who had begun as a secular canon, responded to a desperate need for informed preaching by founding the Order of Preachers and thus embarking on a new form of religious life, the life of the friar. Before this time, religious life had been monastic, but with Dominic the secluded monastery gave way to priories in the cities. By the time of his death in 1221, the Order had spread through Western Europe, hundreds of young men had joined, and the presence of the Order of Preachers was felt at the major universities of the time.

Franciscans.

Francis came to this manner of life through a period of personal conversion. The Franciscans spread far and wide the devotion to the humanity of Christ, with the commitment to imitate the Lord. Many of them were priests and men of learning whose contributions were notable in the rapid evolution and contemporary relevance of the movement. Notable Franciscans include Anthony of Padua, who were inspirations to the formation of Christian mendicant traditions.

Characteristics.

The Franciscans and Dominicans put into practice a pastoral strategy suited to the social changes. The emergence of urban centers meant concentrated numbers of the homeless and the sick. This created problems for the parish churches who found themselves unable to address these issues. Since many people were moving from the countryside to the cities, they no longer built their convents in rural districts but rather in urban zones.  In another innovation, the mendicant orders relinquished their principle of stability, a classical principle of ancient monasticism, opting for a different approach. Unlike the Benedictine monks, the mendicants were not permanently attached to any one particular convent and to its abbot. Because the orders' primary aim was the evangelization of the masses, the church granted them freedom from the jurisdiction of the bishops and they traveled about to convert or reinforce faith. The freedom of mendicancy allowed Franciscans and Dominicans mobility. Since they were not tied to monasteries or territorial parishes, they were free to take the gospel into the streets, to preach, hear confessions and minister to people wherever they were. Friars Minor and Preachers traveled with missionary zeal from one place to another.  Consequently, they organized themselves differently in comparison with the majority of monastic orders. Instead of the traditional autonomy that every monastery enjoyed, they gave greater importance to the order as such and to the Superior General, as well as to the structure of the order Provinces. Their flexibility enabled them to send out the most suitable friars on specific missions, and the mendicant orders reached North Africa, the Middle East and Northern Europe.  As students and professors, Friars Minor and Friars Preacher, Franciscans and Dominicans, entered the leading universities of the time, set up study centers, produced texts of great value and were protagonists of scholastic theology in its best period and had an important effect on the development of thought. The great thinkers, St Thomas Aquinas and St Bonaventure, were mendicants.  In all the great cities of western Europe, friaries were established, and in the universities theological chairs were held by Dominicans and Franciscans. Later in the 13th century they were joined by the mendicant orders of Carmelites, Augustinian Hermits, and Servites.  They attracted a significant level of patronage, as much from townsfolk as aristocrats. Their focus of operation rapidly centered on towns where population growth historically outstripped the provision of rural parishes. Most medieval towns in Western Europe of any size came to possess houses of one or more of the major orders of friars. Some of their churches came to be built on grand scale with large spaces devoted to preaching, something of a specialty among the mendicant orders.

Early mendicant orders.

Despite conforming to a recognizable model, the mendicant orders of friars had origins that were generally very different. The original mendicant orders of friars in the Church in the Middle Ages were the  The Second Council of Lyons (1274) recognized these as the four "major" mendicant orders, and suppressed certain others. The Council of Trent loosened the restrictions on their owning property. Afterwards, except for the Franciscans and their offshoot the Capuchins, members of the orders were permitted to own property collectively as do monks.

Other mendicant orders.

The other mendicant orders recognized by the Holy See today are the  Like the monastic orders, many of the mendicant orders, especially the larger ones, underwent splits and reform efforts, forming offshoots, permanent or otherwise, some of which are mentioned in the lists given above.

Former mendicant orders.

Mendicant orders that formerly existed but are now extinct, and orders which for a time were classed as mendicant orders but now no longer are.

Mendicant orders are, primarily, certain Christian religious orders that have adopted a lifestyle of poverty, traveling, and living in urban areas for purposes of preaching, evangelization, and ministry, especially to the poor. At their foundation these orders rejected the previously established monastic model. This model prescribed living in one stable, isolated community where members worked at a trade and owned property in common, including land, buildings and other wealth. By contrast, the mendicants avoided owning property at all, did not work at a trade, and embraced a poor, often itinerant lifestyle. They depended for their survival on the goodwill of the people to whom they preached.


PC partition types.

This section describes the master boot record (MBR) partitioning scheme, as used historically in DOS, Microsoft Windows and Linux (among others) on PC-compatible computer systems. As of the mid-2010s, most new computers use the GUID Partition Table (GPT) partitioning scheme instead. For examples of other partitioning schemes, see the general article on partition tables.  The total data storage space of a PC HDD on which MBR partitioning is implemented can contain at most four "primary partitions", or alternatively three primary partitions and an "extended partition". The "Partition Table", located in the master boot record, contains 16-byte entries, each of which describes a partition.  The "partition type" is identified by a 1-byte code found in its partition table entry. Some of these codes (such as 0x05 and 0x0F) may be used to indicate the presence of an extended partition. Most are used by an operating system's bootloader (that examines partition tables) to decide if a partition contains a file system that can be "mounted / accessed" for reading or writing data.

Primary partition.

A primary partition contains one file system. In DOS and all early versions of Microsoft Windows systems, Microsoft required what it called the system partition to be the first partition. All Windows operating systems from Windows 95 onwards can be located on (almost) any partition, but the boot files (codice_1, codice_2, codice_3, etc.) must reside on a primary partition. However, other factors, such as a PC's BIOS (see Boot sequence on standard PC) may also impose specific requirements as to which partition must contain the primary OS.  The partition type "code" for a primary partition can either correspond to a file system contained within (e.g. 0x07 means either an NTFS or an OS/2 HPFS file system) or indicate that the partition has a special use (e.g. code 0x82 usually indicates a Linux "swap" partition). The FAT16 and FAT32 file systems have made use of a number of partition type codes due to the limits of various DOS and Windows OS versions. Though a Linux operating system may recognize a number of different file systems (ext4, ext3, ext2, ReiserFS, etc.), they have all consistently used the same partition type code: 0x83 (Linux native file system).

Extended partition.

An HDD may contain only one extended partition, but that extended partition can be subdivided into multiple logical partitions. DOS/Windows systems may then assign a unique drive letter to each logical partition.

Partitioning schemes.

DOS, Windows, and OS/2.

With DOS, Microsoft Windows, and OS/2, a common practice is to use one primary partition for the active file system that will contain the operating system, the page/swap file, all utilities, applications, and user data. On most Windows consumer computers, the drive letter C: is routinely assigned to this primary partition. Other partitions may exist on the HDD that may or may not be visible as drives, such as recovery partitions or partitions with diagnostic tools or data. (Microsoft drive letters do not correspond to partitions in a one-to-one fashion, so there may be more or fewer drive letters than partitions.)  Microsoft Windows 2000, XP, Vista, and Windows 7 include a 'Disk Management' program which allows for the creation, deletion and resizing of FAT and NTFS partitions. The Windows Disk Manager in Windows Vista and Windows 7 utilizes a 1 MB partition alignment scheme which is fundamentally incompatible with Windows 2000, XP, OS/2, DOS as well as many other operating systems.

Unix-like systems.

On Unix-based and Unix-like operating systems such as Linux, macOS, BSD, and Solaris, it is possible to use multiple partitions on a disk device. Each partition can be formatted with a file system or as a swap partition.  Multiple partitions allow directories such as /boot, /tmp, /usr, /var, or /home to be allocated their own filesystems. Such a scheme has a number of advantages:  A common minimal configuration for Linux systems is to use three partitions: one holding the system files mounted on "/" (the root directory), one holding user configuration files and data mounted on /home (home directory), and a swap partition.  By default, macOS systems also use a single partition for the entire filesystem and use a swap file inside the file system (like Windows) rather than a swap partition.  In Solaris, partitions are sometimes known as slices. This is a conceptual reference to the slicing of a cake into several pieces.  The term "slice" is used in the FreeBSD operating system to refer to Master Boot Record partitions, to avoid confusion with FreeBSD's own disklabel-based partitioning scheme. However, GUID Partition Table partitions are referred to as "partition" worldwide.

Multi-boot and mixed-boot systems.

Multi-boot systems are computers where the user can boot into one of two or more distinct operating systems (OS) stored in separate storage devices or in separate partitions of the same storage device. In such systems a menu at startup gives a choice of which OS to boot/start (and only one OS at a time is loaded).  This is distinct from virtual operating systems, in which one operating system is run as a self-contained virtual "program" within another already-running operating system. (An example is a Windows OS "virtual machine" running from within a Linux OS.)

GUID Partition Table.

The GUID Partition Table (Globally Unique IDentifier) is a part of the Unified Extensible Firmware Interface (UEFI) standard for the layout of the partition table on a physical hard disk. Many operating systems now support this standard.

Partition recovery.

When a partition is deleted, its entry is removed from a table and the data is no longer accessible. The data remains on the disk until being overwritten. Specialized recovery utilities may be able to locate "lost" file systems and recreate a partition table which includes entries for these recovered file systems. Some disk utilities may overwrite a number of beginning sectors of a partition they delete. For example, if Windows Disk Management (Windows 2000/XP, etc.) is used to delete a partition, it will overwrite the first sector (relative sector 0) of the partition before removing it. It still may be possible to restore a FAT or NTFS partition if a backup boot sector is available.

Compressed disks.

HDDs can be compressed to create additional space. In DOS and early Microsoft Windows, programs such as Stacker (DR-DOS except 6.0), SuperStor (DR DOS 6.0), DoubleSpace (MS-DOS 6.0–6.2), or DriveSpace (MS-DOS 6.22, Windows 9x) were used. This compression was done by creating a very large file on the partition, then storing the disk's data in this file. At startup, device drivers opened this file and assigned it a separate letter. Frequently, to avoid confusion, the original partition and the compressed drive had their letters swapped, so that the compressed disk is C:, and the uncompressed area (often containing system files) is given a higher name.  Versions of Windows using the NT kernel, including the most recent version, Windows 10, contain intrinsic disk compression capability. The use of separate disk compression utilities has declined sharply.

Disk partitioning or disk slicing is the creation of one or more regions on secondary storage, so that each region can be managed separately. These regions are called partitions. It is typically the first step of preparing a newly installed disk, before any file system is created. The disk stores the information about the partitions' locations and sizes in an area known as the partition table that the operating system reads before any other part of the disk. Each partition then appears to the operating system as a distinct "logical" disk that uses part of the actual disk. System administrators use a program called a partition editor to create, resize, delete, and manipulate the partitions.. Partitioning allows the use of different filesystems to be installed for different kinds of files. Separating user data from system data can prevent the system partition from becoming full and rendering the system unusable. Partitioning can also make backing up easier. A disadvantage is that it can be difficult to properly size partitions, resulting in having one partition with much free space and another nearly totally allocated.


History.

When the Macedonian army of Alexander the Great reached the Jaxartes in 329 BCE, after travelling through Bactria and Sogdia without encountering any opposition, they met with the first instances of native resistance to their presence. Alexander was wounded in the fighting that ensued and the native tribes took to massacring the Macedonian garrisons stationed in their towns. As the revolt against Alexander intensified it spread through Sogdia, plunging it into two years of warfare, the intensity of which surpassed any other conflict of the "Anabasis Alexandri".  On the shores of the Syr Darya Alexander placed a garrison in the City of Cyrus (Cyropolis in Greek), which he then renamed after himself Alexandria Eschate—"the farthest Alexandria"—in 329 BCE. For most of its history since at least the Muslim conquest of Central Asia in the 7th to 8th centuries CE, the name of this city (in present-day Tajikistan) has been Khujand.  In the mid-19th century, during the Russian conquest of Turkestan, the Russian Empire introduced steam navigation to the Syr Darya, with an important river port at Kazalinsk (Kazaly) from 1847 to 1882, when service ceased.  During the Soviet era, a resource-sharing system was instituted in which Kyrgyzstan and Tajikistan shared water originating from the Amu Darya and Syr Darya rivers with Kazakhstan, Turkmenistan, and Uzbekistan in summer. In return, Kyrgyzstan and Tajikistan received Kazakh, Turkmen, and Uzbek coal, gas, and electricity in winter. After the 1991 fall of the Soviet Union this system disintegrated and the Central Asian nations have failed to reinstate it. Inadequate infrastructure, poor water-management, and outdated irrigation methods all exacerbate the issue.

Geography.

The river rises in two headstreams in the Tian Shan Mountains in Kyrgyzstan and eastern Uzbekistan—the Naryn River and the Kara Darya which come together in the Uzbek part of the Fergana Valley—and flows for some west and north-west through Uzbekistan and southern Kazakhstan to the remains of the Aral Sea. The Syr Darya drains an area of over, but no more than actually contribute significant flow to the river: indeed, two of the largest rivers in its basin, the Talas and the Chu, dry up before reaching it. Its annual flow is a very modest per year—half that of its sister river, the Amu Darya.  Along its course, the Syr Darya irrigates the most productive cotton-growing region in the whole of Central Asia, together with the towns of Kokand, Khujand, Kyzylorda and Turkestan.  Various local governments throughout history have built and maintained an extensive system of canals. These canals are of central importance in this arid region. Many fell into disuse in the 17th and early 18th century, but the Khanate of Kokand rebuilt many in the 19th century, primarily along the Upper and Middle Syr Darya.

Name.

The second part of the name ("darya", دریا) means "river" or "sea" in Persian. The current name dates only from the 18th century.  The earliest recorded name was "Jaxartes" or "Iaxartes" () in Ancient Greek, consist of two morpheme "Iaxa" and "artes", found in several sources, including those relating to Alexander the Great. The Greek name hearkens back to the Old Persian name "Yakhsha Arta" ("True Pearl"), perhaps a reference to the color of its glacially-fed water. More evidence for the Persian etymology comes from the river's Turkic name up to the time of the Arab conquest, the "Yinchu", or "Pearl river". Tang China also recorded this name as Yiakshaet River 藥殺水 and later Ye River 葉河.  Following the Muslim conquest, the river appears in the sources uniformly as the "Seyhun" (سيحون), one of the four rivers flowing from the Paradise (Jannah in Arabic).  The current local name of the river, "Syr" ("Sïr"), does not appear before the 16th century. In the 17th century, Abu al-Ghazi Bahadur Khan, historian and ruler of Khiva, called the Aral Sea the "Sea of Sïr," or "Sïr Tengizi".

Ecological damage.

Massive expansion of irrigation canals in Middle and Lower Syr Darya during the Soviet period to water cotton and rice fields caused ecological damage to the area. The amount of water taken from the river was such that in some periods of the year, no water at all reached the Aral Sea. The Amu Darya in Uzbekistan and Turkmenistan faced a similar situation.  The uranium concentration of the stream water is increased in Tajikistan with values of 43 μg/l and 12 μg/l; the WHO guideline value for drinking water of 30 μg/l is partly exceeded. The main input of uranium occurs upstream in Uzbekistan and Kyrgyzstan.

The Syr Darya (, ), historically known as the Jaxartes (), is a river in Central Asia. The name, a borrowing from the Persian language, literally means "Syr Sea" or "Syr River", and sometimes it is referred to in this way. It originates in the Tian Shan Mountains in Kyrgyzstan and eastern Uzbekistan and flows for west and north-west through Uzbekistan and southern Kazakhstan to the northern remnants of the Aral Sea. It is the northern and eastern of the two main rivers in the endorrheic basin of the Aral Sea, the other being the Amu Darya (Jayhun). In the Soviet era, extensive irrigation projects were constructed around both rivers, diverting their water into farmland and causing, during the post-Soviet era, the virtual disappearance of the Aral Sea, once the world's fourth-largest lake. The point at which the river flows from Tajikistan into Uzbekistan is, at above sea level, the lowest elevation in Tajikistan.


Life.

He was born in Lanz in Brandenburg, Prussia. He studied theology and philology from 1796 to 1802 at the Halle, Göttingen, and at the University of Greifswald. After the Battle of Jena–Auerstedt in 1806 he joined the Prussian army. In 1809, he went to Berlin, where he became a teacher at the Gymnasium zum Grauen Kloster and at the Plamann School.  Brooding upon what he saw as the humiliation of his native land by Napoleon, Jahn conceived the idea of restoring the spirits of his countrymen by the development of their physical and moral powers through the practice of gymnastics. The first "Turnplatz", or open-air gymnasium, was opened by Jahn in Berlin in 1811, and the "Turnverein" (gymnastics association) movement spread rapidly. Young gymnasts were taught to regard themselves as members of a kind of guild for the emancipation of their fatherland. The nationalistic spirit was nourished in a significant degree by the writings of Jahn.  In the Early 1813 Jahn took an active part in the formation of the famous Lützow Free Corps, a volunteer force in the Prussian army fighting Napoleon. He commanded a battalion of the corps, but he was often employed in the secret service during the same period. After the war, he returned to Berlin, where he was appointed state teacher of gymnastics, and he took on a role in the formation of the student patriotic fraternities, or Burschenschaften, in Jena.  A man of populistic nature, rugged, eccentric and outspoken, Jahn often came into conflict with the authorities. The authorities finally realized he aimed at establishing a united Germany and that his "Turner" schools were political and liberal clubs. The conflict resulted in the closing of the "Turnplatz" in 1819 and Jahn's arrest. Kept in semi-confinement successively at Spandau, Küstrin, and at the fortress in Kolberg until 1824, he was sentenced to imprisonment for two years. The sentence was reversed in 1825, but he was forbidden to live within ten miles of Berlin.  He therefore took up residence at Freyburg on the Unstrut, where he remained until his death, with the exception of a short period in 1828, when he was exiled to Kölleda on a charge of sedition. While at Freyburg, he received an invitation to become professor of German literature at Cambridge, Massachusetts, which he declined, saying that “deer and hares love to live where they are most hunted.” In 1840, Jahn was decorated by the Prussian government with the Iron Cross for bravery in the wars against Napoleon. In the spring of 1848, he was elected by the district of Naumburg to the German National Parliament. Jahn died in Freyburg, where a monument was erected in his honor in 1859.  Jahn popularized the "four Fs" motto "frisch, fromm, fröhlich, frei" ("fresh, pious, cheerful, free") in the early 19th century.

Works.

Among his works are the following: A complete edition of his works appeared at Hof in 1884-1887. See the biography by Schultheiss (Berlin, 1894), and "Jahn als Erzieher", by Friedric (Munich, 1895).

Contribution to physical education.

Jahn promoted the use of parallel bars, rings and the high bar in international competition. In honor and memory of him, some gymnastic clubs, called "Turnvereine" (German:"Turnvereine"), took up his name, the most well known of these is probably the SSV Jahn Regensburg.  A memorial to Jahn exists in St. Louis, Missouri, within Forest Park. It features a large bust of Jahn in the center of an arc of stone, with statues of a male and female gymnast, one on each end of the arc. The monument is on the edge of Art Hill next to the path running north and south along the western edge of Post-Dispatch lake. It is directly north of the St. Louis Zoo.  Other memorials to Jahn are located in Groß-Gerau, Germany; in Vienna, Austria; and in Inwood Park, in the Mt. Auburn neighborhood of Cincinnati. An elementary school in Chicago is named after Jahn.

Criticism.

In his own time Friedrich Jahn was seen by both supporters and opponents as a liberal figure. He advocated that the German states should unite after the withdrawal of Napoleon's occupying armies, and establish a democratic constitution (under the Hohenzollern monarchy), which would include the right to free speech. As a German nationalist, Jahn advocated maintaining German language and culture against foreign influence. In 1810 he wrote, "Poles, French, priests, aristocrats and Jews are Germany's misfortune." At the time Jahn wrote this, the German states were occupied by foreign armies under the leadership of Napoleon. Also, Jahn was "the guiding spirit" of the fanatic book burning episode carried out by revolutionary students at the Wartburg festival in 1817.  Jahn gained infamy in English-speaking countries through the publication of Peter Viereck's "Metapolitics: The Roots of the Nazi Mind" (1941). Viereck claimed Jahn as the spiritual founder of Nazism, who inspired the early German romantics with anti-Semitic and authoritarian doctrines, and then influenced Wagner and finally the Nazis.  However, Jacques Barzun observed that Viereck's portrait of cultural trends supposedly leading to Nazism was "a caricature without resemblance" relying on "misleading shortcuts".  Scholarly focus on the völkischness of Jahn's thought started in the 1920s with a new generation of Jahn interpreters like Edmund Neuendorff and Karl Müller. Neuendorff explicitly linked Jahn with National Socialism. The equation by the National Socialists of Jahn's ideas with their world view was more or less complete by the mid-1930s. Alfred Baeumler, an educational philosopher and university lecturer who attempted to provide theoretical support for Nazi ideology (through the interpretation of Nietzsche among others) wrote a monograph on Jahn in which he characterises Jahn's invention of gymnastics as an explicitly political project, designed to create the ultimate völkisch citizen by educating his body.

Friedrich Ludwig Jahn (11 August 1778 – 15 October 1852) was a German gymnastics educator and nationalist whose writing is credited with the founding of the German gymnastics (Turner) movement as well as influencing the German Campaign of 1813, during which a coalition of German states effectively ended the occupation of Napoleon's First French Empire. His admirers know him as "Turnvater Jahn", roughly meaning "father of gymnastics" Jahn.


Life.

His school master was Joseph Gebhard Himmler, the father of Heinrich Himmler. He wrote about this in "The Father of a Murderer".

1914 to 1945.

In 1930, after an apprenticeship as a bookseller, Andersch became a youth leader in the Communist Party. As a consequence, he was held for 6 months in the Dachau concentration camp in 1933. He then left the party and entered a depressive phase of "total introversion". It was during this period that he first became engaged in the arts, adopting the stance that became known as "innere Emigration" ("internal emigration") – despite remaining in Germany, he was spiritually opposed to Hitler's regime.  In 1940, Andersch was conscripted into the Wehrmacht, but deserted at the Arno Line in Italy on 6 June 1944. He was taken to the United States as a prisoner of war and interned at Camp Ruston, Louisiana and other POW camps. He became the editor of a prisoners' newspaper, "Der Ruf" ("The Call").  A critical review of Andersch's "internal émigré" status, his marriage to a German Jew and subsequent divorce in 1943, as well as of his writing, may be read in W.G. Sebald's "Between the Devil and the Deep Blue Sea" attached to his essay "On the Natural History of Destruction". Sebald accused Andersch of having presented through literature a version of his life (and of the "internal emigration" more generally) that made it sound more acceptable to a post-Nazi public.

1945 to 1980.

Having returned to Germany, he worked from 1945 as an editing assistant for Erich Kästner's "Neue Zeitung" in Munich. From 1946 to 1947, he worked alongside Hans Werner Richter to publish the monthly literary journal "Der Ruf", which was sold in the American occupation zone of Germany. The publication was discontinued following the non-renewal of its license by the U.S military government. Presumably, the discontinuation of "Der Ruf" followed "promptings by the Soviet authorities, provoked by Hans Werner Richter's open letter to the French Stalinist, Marcel Cachin." In the following years, Andersch worked with the literary circle "Group 47", members of which included the authors Ingeborg Bachmann, Wolfgang Hildesheimer, Arno Schmidt, Hans Magnus Enzensberger and Helmut Heissenbüttel, among others. 1948 saw the publication of Andersch's essay "Deutsche Literatur in der Entscheidung" ("German Literature at the Turning Point"), in which he concluded, in the spirit of the American post-war "re-education" programme, that literature would play a decisive role in the moral and intellectual changes in Germany.  Beginning in 1948, Andersch was a leading figure at radio stations in Frankfurt and Hamburg. In 1950, he married the painter Gisela Dichgans. His autobiographical work "Die Kirschen der Freiheit" ("The Cherries of Freedom") was published in 1952, in which Andersch dealt with the experience of his wartime desertion and interpreted it as the "turning point" ("Entscheidung") at which he could first feel free. On a similar theme, he published in 1957 perhaps the most significant work of his career, "Sansibar oder der letzte Grund" (published in English as "Flight to Afar"). A few of Andersch's books were turned into films.  From 1958, Andersch lived in Berzona in Switzerland, where he became mayor in 1972. After "Sansibar" followed the novels "Die Rote" in 1960, "Efraim" in 1967, and, in 1974, "Winterspelt", which is, thematically, very similar to "Sansibar", but is more complex in its composition. In 1977, he published the poetry anthology "empört euch der himmel ist blau". Alfred Andersch died on 21 February 1980 in Berzona, Ticino. The incomplete story "Der Vater eines Mörders" ("The Father of a Murderer") was published posthumously in the same year.

Themes.

Alfred Andersch served as an analyst of contemporary issues for the post-war generation. In his works, he described, above all, outsiders, and dealt with his political and moral experiences. He often raised questions about the free will of the individual as a central theme. In numerous essays, he stated his opinion on literary and cultural issues; he frequently pointed out the importance of Ernst Jünger.

Works.

Critical edition.

On 21 February 2005, to commemorate the 25th anniversary of Andersch's death, Diogenes Press released a critical edition of his complete works. The ten volumes also include previously unpublished texts that come from his estate.

Alfred Hellmuth Andersch (; 4 February 1914 – 21 February 1980) was a German writer, publisher, and radio editor. The son of a conservative East Prussian army officer, he was born in Munich, Germany and died in Berzona, Ticino, Switzerland. Martin Andersch, his brother, was also a writer.


Etymology.

The word "electrolyte" derives from Ancient Greek ήλεκτρο- ("ēlectro"-), prefix related to electricity, and λυτός ("lytos"), meaning "able to be untied or loosened".

History.

In his 1884 dissertation Svante Arrhenius put forth his explanation of solid crystalline salts disassociating into paired charged particles when dissolved, for which he won the 1903 Nobel Prize in Chemistry.  Arrhenius's explanation was that in forming a solution, the salt dissociates into charged particles, to which Michael Faraday had given the name "ions" many years earlier. Faraday's belief had been that ions were produced in the process of electrolysis. Arrhenius proposed that, even in the absence of an electric current, solutions of salts contained ions. He thus proposed that chemical reactions in solution were reactions between ions.

Formation.

Electrolyte solutions are normally formed when salt is placed into a solvent such as water and the individual components dissociate due to the thermodynamic interactions between solvent and solute molecules, in a process called "solvation". For example, when table salt (sodium chloride), NaCl, is placed in water, the salt (a solid) dissolves into its component ions, according to the dissociation reaction It is also possible for substances to react with water, producing ions. For example, carbon dioxide gas dissolves in water to produce a solution that contains hydronium, carbonate, and hydrogen carbonate ions.  Molten salts can also be electrolytes as, for example, when sodium chloride is molten, the liquid conducts electricity. In particular, ionic liquids, which are molten salts with melting points below 100 °C, are a type of highly conductive non-aqueous electrolytes and thus have found more and more applications in fuel cells and batteries.  An electrolyte in a solution may be described as "concentrated" if it has a high concentration of ions, or "diluted" if it has a low concentration. If a high proportion of the solute dissociates to form free ions, the electrolyte is strong; if most of the solute does not dissociate, the electrolyte is weak. The properties of electrolytes may be exploited using electrolysis to extract constituent elements and compounds contained within the solution.  Alkaline earth metals form hydroxides that are strong electrolytes with limited solubility in water, due to the strong attraction between their constituent ions. This limits their application to situations where high solubility is required.

Physiological importance.

In physiology, the primary ions of electrolytes are sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl), hydrogen phosphate (HPO), and hydrogen carbonate (HCO). The electric charge symbols of plus (+) and minus (−) indicate that the substance is ionic in nature and has an imbalanced distribution of electrons, the result of chemical dissociation. Sodium is the main electrolyte found in extracellular fluid and potassium is the main intracellular electrolyte; both are involved in fluid balance and blood pressure control.  All known multicellular lifeforms require a subtle and complex electrolyte balance between the intracellular and extracellular environments. In particular, the maintenance of precise osmotic gradients of electrolytes is important. Such gradients affect and regulate the hydration of the body as well as blood pH, and are critical for nerve and muscle function. Various mechanisms exist in living species that keep the concentrations of different electrolytes under tight control.  Both muscle tissue and neurons are considered electric tissues of the body. Muscles and neurons are activated by electrolyte activity between the extracellular fluid or interstitial fluid, and intracellular fluid. Electrolytes may enter or leave the cell membrane through specialized protein structures embedded in the plasma membrane called "ion channels". For example, muscle contraction is dependent upon the presence of calcium (Ca), sodium (Na), and potassium (K). Without sufficient levels of these key electrolytes, muscle weakness or severe muscle contractions may occur.  Electrolyte balance is maintained by oral, or in emergencies, intravenous (IV) intake of electrolyte-containing substances, and is regulated by hormones, in general with the kidneys flushing out excess levels. In humans, electrolyte homeostasis is regulated by hormones such as antidiuretic hormones, aldosterone and parathyroid hormones. Serious electrolyte disturbances, such as dehydration and overhydration, may lead to cardiac and neurological complications and, unless they are rapidly resolved, will result in a medical emergency.

Measurement.

Measurement of electrolytes is a commonly performed diagnostic procedure, performed via blood testing with ion-selective electrodes or urinalysis by medical technologists. The interpretation of these values is somewhat meaningless without analysis of the clinical history and is often impossible without parallel measurements of renal function. The electrolytes measured most often are sodium and potassium. Chloride levels are rarely measured except for arterial blood gas interpretations since they are inherently linked to sodium levels. One important test conducted on urine is the specific gravity test to determine the occurrence of an electrolyte imbalance.

Rehydration.

In oral rehydration therapy, electrolyte drinks containing sodium and potassium salts replenish the body's water and electrolyte concentrations after dehydration caused by exercise, excessive alcohol consumption, diaphoresis (heavy sweating), diarrhea, vomiting, intoxication or starvation. Athletes exercising in extreme conditions (for three or more hours continuously, e.g. a marathon or triathlon) who do not consume electrolytes risk dehydration (or hyponatremia).  A home-made electrolyte drink can be made by using water, sugar and salt in precise proportions. It is important to include glucose (sugar) to utilise the co-transport mechanism of sodium and glucose. Commercial preparations are also available for both human and veterinary use.  Electrolytes are commonly found in fruit juices, sports drinks, milk, nuts, and many fruits and vegetables (whole or in juice form) (e.g., potatoes, avocados).

Electrochemistry.

When electrodes are placed in an electrolyte and a voltage is applied, the electrolyte will conduct electricity. Lone electrons normally cannot pass through the electrolyte; instead, a chemical reaction occurs at the cathode, providing electrons to the electrolyte. Another reaction occurs at the anode, consuming electrons from the electrolyte. As a result, a negative charge cloud develops in the electrolyte around the cathode, and a positive charge develops around the anode. The ions in the electrolyte neutralize these charges, enabling the electrons to keep flowing and the reactions to continue.  For example, in a solution of ordinary table salt (sodium chloride, NaCl) in water, the cathode reaction will be and hydrogen gas will bubble up; the anode reaction is and chlorine gas will be liberated. The positively charged sodium ions Na will react toward the cathode, neutralizing the negative charge of OH there, and the negatively charged hydroxide ions OH will react toward the anode, neutralizing the positive charge of Na there. Without the ions from the electrolyte, the charges around the electrode would slow down continued electron flow; diffusion of H and OH through water to the other electrode takes longer than movement of the much more prevalent salt ions. Electrolytes dissociate in water because water molecules are dipoles and the dipoles orient in an energetically favorable manner to solvate the ions.  In other systems, the electrode reactions can involve the metals of the electrodes as well as the ions of the electrolyte.  Electrolytic conductors are used in electronic devices where the chemical reaction at a metal-electrolyte interface yields useful effects.

Solid electrolytes.

Solid electrolytes can be mostly divided into four groups:

An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water. The dissolved electrolyte separates into cations and anions, which disperse uniformly through the solvent. Electrically, such a solution is neutral. If an electric potential is applied to such a solution, the cations of the solution are drawn to the electrode that has an abundance of electrons, while the anions are drawn to the electrode that has a deficit of electrons. The movement of anions and cations in opposite directions within the solution amounts to a current. This includes most soluble salts, acids, and bases. Some gases, such as hydrogen chloride, under conditions of high temperature or low pressure can also function as electrolytes. Electrolyte solutions can also result from the dissolution of some biological (e.g., DNA, polypeptides) and synthetic polymers (e.g., polystyrene sulfonate), termed "polyelectrolytes", which contain charged functional groups. A substance that dissociates into ions in solution acquires the capacity to conduct electricity. Sodium, potassium, chloride, calcium, magnesium, and phosphate are examples of electrolytes.