Geography and hydrography.

Lake Baikal is in a rift valley, created by the Baikal Rift Zone, where the Earth's crust is slowly pulling apart. At long and wide, Lake Baikal has the largest surface area of any freshwater lake in Asia, at, and is the deepest lake in the world at. The bottom of the lake is below sea level, but below this lies some of sediment, placing the rift floor some below the surface, the deepest continental rift on Earth. In geological terms, the rift is young and active – it widens about 2 cm (0.8 in) per year. The fault zone is also seismically active; hot springs occur in the area and notable earthquakes happen every few years. The lake is divided into three basins: North, Central, and South, with depths about,, and, respectively. Fault-controlled accommodation zones rising to depths about separate the basins. The North and Central basins are separated by Academician Ridge, while the area around the Selenga Delta and the Buguldeika Saddle separates the Central and South basins. The lake drains into the Angara, a tributary of the Yenisey. Notable landforms include Cape Ryty on Baikal's northwest coast.  Baikal's age is estimated at 25–30 million years, making it the most ancient lake in geological history. It is unique among large, high-latitude lakes, as its sediments have not been scoured by overriding continental ice sheets. Russian, U.S., and Japanese cooperative studies of deep-drilling core sediments in the 1990s provide a detailed record of climatic variation over the past 6.7 million years. Longer and deeper sediment cores are expected in the near future. Lake Baikal is the only confined freshwater lake in which direct and indirect evidence of gas hydrates exists.  The lake is surrounded by mountains; the Baikal Mountains on the north shore, the Barguzin Range on the northeastern shore, and the taiga are protected as a national park. It contains 27 islands; the largest, Olkhon, is long and is the third-largest lake-bound island in the world. The lake is fed by as many as 330 inflowing rivers. The main ones draining directly into Baikal are the Selenga, the Barguzin, the Upper Angara, the Turka, the Sarma, and the Snezhnaya. It is drained through a single outlet, the Angara.

Water characteristics.

Baikal is one of the clearest lakes in the world. During the winter, the water transparency in open sections can be as much as, but during the summer it is typically. Baikal is rich in oxygen, even in deep sections, which separates it from distinctly stratified bodies of water such as Lake Tanganyika and the Black Sea.  In Lake Baikal, the water temperature varies significantly depending on location, depth, and time of the year. During the winter and spring, the surface freezes for about 4–5 months; from early January to early May–June (latest in the north), the lake surface is covered in ice. On average, the ice reaches a thickness of, but in some places with hummocks, it can be more than. During this period, the temperature slowly increases with depth in the lake, being coldest near the ice-covered surface at around freezing, and reaching about at a depth of. After the surface ice breaks up, the surface water is slowly warmed up by the sun, and in May–June, the upper or so becomes homothermic (same temperature throughout) at around because of water mixing. The sun continues to heat up the surface layer, and at the peak in August can reach up to about in the main sections and in shallow bays in the southern half of the lake. During this time, the pattern is inverted compared to the winter and spring, as the water temperature falls with increasing depth. As the autumn begins, the surface temperature falls again and a second homothermic period at around of the upper circa occurs in October–November. In the deepest parts of the lake, from about, the temperature is stable at with only minor annual variations.  The average surface temperature has risen by almost 1.5 °C (2.7 °F) in the last 50 years, resulting in a shorter period where the lake is covered by ice. At some locations, hydrothermal vents with water that is about have been found. These are mostly in deep water, but locally have also been found in relatively shallow water. They have little effect on the lake's temperature because of its huge volume.  Stormy weather on the lake is common, especially during the summer and fall, and can result in waves as high as.

Fauna and flora.

Lake Baikal is rich in biodiversity. It hosts more than 1,000 species of plants and 2,500 species of animals based on current knowledge, but the actual figures for both groups are believed to be significantly higher. More than 80% of the animals are endemic.

Flora.

The watershed of Lake Baikal has numerous floral species represented. The marsh thistle ("Cirsium palustre") is found here at the eastern limit of its geographic range.  Submerged macrophytic vascular plants are mostly absent, except in some shallow bays along the shores of Lake Baikal. More than 85 species of submerged macrophytes have been recorded, including genera such as "Ceratophyllum", "Myriophyllum", "Potamogeton", and "Sparganium". The invasive species "Elodea canadensis" was introduced to the lake in the 1950s. Instead of vascular plants, aquatic flora is often dominated by several green algae species, notably "Draparnaldioides", "Tetraspora", and "Ulothrix" in water shallower than ; although "Aegagrophila", "Cladophora", and "Draparnaldioides" may occur deeper than. Except for "Ulothrix", there are endemic Baikal species in all these green algae genera. More than 400 diatom species, both benthic and planktonic, are found in the lake, and about half of these are endemic to Baikal; however, significant taxonomic uncertainties remain for this group.

Mammals.

The Baikal seal or "nerpa" ("Pusa sibirica") is found throughout Lake Baikal. It is one of only three entirely freshwater seal populations in the world, the other two being subspecies of ringed seals.  A wide range of land mammals can be found in the habitats around the lake, such as Eurasian brown bear, Eurasian wolf, red fox, sable, stoat, elk, Siberian red deer, reindeer, Siberian roe deer, Siberian musk deer, wild boar, red squirrel, Siberian chipmunk, marmot, lemming, and Alpine hare. Until the Early Middle Ages, the wisent (European bison) was present near the lake, which was the easternmost part of its range.

Birds.

There are 236 species of birds that inhabit Lake Baikal, 29 of which are waterfowl. Although named after the lake, both the Baikal teal and Baikal bush warbler are widespread in eastern Asia.

Fish.

Fewer than 65 native fish species occur in the lake basin, but more than half of these are endemic. The families Abyssocottidae (deep-water sculpins), Comephoridae (golomyankas or Baikal oilfish), and Cottocomephoridae (Baikal sculpins) are entirely restricted to the lake basin. All these are part of the Cottoidea and are typically less than long. Of particular note are the two species of golomyanka ("Comephorus baicalensis" and "C. dybowskii"). These long-finned, translucent fish typically live in open water at depths of, but occur both shallower and much deeper. Together with certain abyssocottid sculpins, they are the deepest living freshwater fish in the world, occurring to near the bottom of Lake Baikal. The golomyankas are the primary prey of the Baikal seal and represent the largest fish biomass in the lake. Beyond members of Cottoidea, there are few endemic fish species in the lake basin. The most important local species for fisheries is the omul ("Coregonus migratorius"), an endemic whitefish. It is caught, smoked, and then sold widely in markets around the lake. Also, a second endemic whitefish inhabits the lake, "C. baicalensis". The Baikal black grayling ("Thymallus baicalensis"), Baikal white grayling ("T. brevipinnis"), and Baikal sturgeon ("Acipenser baerii baicalensis") are other important species with commercial value. They are also endemic to the Lake Baikal basin.

Invertebrates.

The lake hosts a rich endemic fauna of invertebrates. The copepod "Epischura baikalensis" is endemic to Lake Baikal and the dominating zooplankton species there, making up 80 to 90% of total biomass. It is estimated that the epischurans filter as much as a thousand cubic kilometers of water a year, or the lake's entire volume every twenty-three years.  Among the most diverse invertebrate groups are the amphipod and ostracod crustaceans, freshwater snails, annelid worms and turbellarian worms:

Amphipod and ostracod crustaceans.

More than 350 species and subspecies of amphipods are endemic to the lake. They are exceptionally diverse in ecology and appearance, ranging from the pelagic "Macrohectopus" to the relatively large deep-water "Abyssogammarus" and "Garjajewia", the tiny herbivorous "Micruropus", and the parasitic "Pachyschesis" (parasitic on other amphipods). The "gigantism" of some Baikal amphipods, which has been compared to that seen in Antarctic amphipods, has been linked to the high level of dissolved oxygen in the lake. Among the "giants" are several species of spiny "Acanthogammarus" and "Brachyuropus" (Acanthogammaridae) found at both shallow and deep depths. These conspicuous and common amphipods are essentially carnivores (will also take detritus), and can reach a body length up to.  Similar to another ancient lake, Tanganyika, Baikal is a center for ostracod diversity. About 90% of the Lake Baikal ostracods are endemic, meaning that there are 200 endemic species. This makes it the second-most diverse group of crustacean in the lake, after the amphipods. The vast majority of the Baikal ostracods belong in the families Candonidae (more than 100 described species) and Cytherideidae (about 50 described species), but genetic studies indicate that the true diversity in at least the latter family has been heavily underestimated. The morphology of the Baikal ostracods is highly diverse.

Snails and bivalves.

, almost 150 freshwater snails are known from Lake Baikal, including 117 endemic species from the subfamilies Baicaliinae (part of the Amnicolidae) and Benedictiinae (part of the Lithoglyphidae), and the families Planorbidae and Valvatidae. All endemics have been recorded between, but the majority mainly live at shallower depths. About 30 freshwater snail species can be seen deeper than, which represents the approximate limit of the sunlight zone, but only 10 are truly deepwater species. In general, Baikal snails are thin-shelled and small. Two of the most common species are "Benedictia baicalensis" and "Megalovalvata baicalensis". Bivalve diversity is lower with more than 30 species; about half of these, all in the families Euglesidae, Pisidiidae, and Sphaeriidae, are endemic (the only other family in the lake is the Unionidae with a single nonendemic species). The endemic bivalves are mainly found in shallows, with few species from deep water.

Aquatic worms.

With almost 200 described species, including more than 160 endemics, the center of diversity for aquatic freshwater oligochaetes is Lake Baikal. A smaller number of other freshwater annelids is known: 30 species of leeches (Hirudinea), and 4 polychaetes. Several hundred species of nematodes are known from the lake, but a large percentage of these are undescribed.  More than 140 endemic flatworm (Plathelminthes) species are in Lake Baikal, where they occur on a wide range of bottom types. Most of the flatworms are predatory, and some are relatively brightly marked. They are often abundant in shallow waters, where they are typically less than long, but in deeper parts of the lake, the largest, "Baikaloplana valida", can reach up to when outstretched.

Sponges.

At least 18 species of sponges occur in the lake, including 14 species from the endemic family Lubomirskiidae (the remaining are from the nonendemic family Spongillidae). In the nearshore regions of Baikal, the largest benthic biomass is sponges. "Lubomirskia baicalensis", "Baikalospongia bacillifera", and "B. intermedia" are unusually large for freshwater sponges and can reach or more. These three are also the most common sponges in the lake. While the "Baikalospongia" species typically have encrusting or carpet-like structures, "L. baikalensis" often has branching structures and in areas where common may form underwater "forests". Most sponges in the lake are typically green when alive because of symbiotic chlorophytes (zoochlorella), but can also be brownish or yellowish.

History.

The Baikal area, sometimes known as Baikalia, has a long history of human habitation. Near the village of Mal'ta, some 160 km northwest of the lake, remains of a young human male known as MA-1 or "Mal'ta Boy" are indications of local habitation by the Mal'ta–Buret' culture ca. 24,000 BP. An early known tribe in the area was the Kurykans.  Located in the former northern territory of the Xiongnu confederation, Lake Baikal is one site of the Han–Xiongnu War, where the armies of the Han dynasty pursued and defeated the Xiongnu forces from the second century BC to the first century AD. They recorded that the lake was a "huge sea" ("hanhai") and designated it the North Sea ("Běihǎi") of the semimythical Four Seas. The Kurykans, a Siberian tribe who inhabited the area in the sixth century, gave it a name that translates to "much water". Later on, it was called "natural lake" ("Baygal nuur") by the Buryats and "rich lake" ("Bay göl") by the Yakuts. Little was known to Europeans about the lake until Russia expanded into the area in the 17th century. The first Russian explorer to reach Lake Baikal was Kurbat Ivanov in 1643.  Russian expansion into the Buryat area around Lake Baikal in 1628–58 was part of the Russian conquest of Siberia. It was done first by following the Angara River upstream from Yeniseysk (founded 1619) and later by moving south from the Lena River. Russians first heard of the Buryats in 1609 at Tomsk. According to folktales related a century after the fact, in 1623, Demid Pyanda, who may have been the first Russian to reach the Lena, crossed from the upper Lena to the Angara and arrived at Yeniseysk.  Vikhor Savin (1624) and Maksim Perfilyev (1626 and 1627–28) explored Tungus country on the lower Angara. To the west, Krasnoyarsk on the upper Yenisei was founded in 1627. A number of ill-documented expeditions explored eastward from Krasnoyarsk. In 1628, Pyotr Beketov first encountered a group of Buryats and collected "yasak" (tribute) from them at the future site of Bratsk. In 1629, Yakov Khripunov set off from Tomsk to find a rumored silver mine. His men soon began plundering both Russians and natives. They were joined by another band of rioters from Krasnoyarsk, but left the Buryat country when they ran short of food. This made it difficult for other Russians to enter the area. In 1631, Maksim Perfilyev built an "ostrog" at Bratsk. The pacification was moderately successful, but in 1634, Bratsk was destroyed and its garrison killed. In 1635, Bratsk was restored by a punitive expedition under Radukovskii. In 1638, it was besieged unsuccessfully.  In 1638, Perfilyev crossed from the Angara over the Ilim portage to the Lena River and went downstream as far as Olyokminsk. Returning, he sailed up the Vitim River into the area east of Lake Baikal (1640) where he heard reports of the Amur country. In 1641, Verkholensk was founded on the upper Lena. In 1643, Kurbat Ivanov went further up the Lena and became the first Russian to see Lake Baikal and Olkhon Island. Half his party under Skorokhodov remained on the lake, reached the Upper Angara at its northern tip, and wintered on the Barguzin River on the northeast side.  In 1644, Ivan Pokhabov went up the Angara to Baikal, becoming perhaps the first Russian to use this route, which is difficult because of the rapids. He crossed the lake and explored the lower Selenge River. About 1647, he repeated the trip, obtained guides, and visited a 'Tsetsen Khan' near Ulan Bator. In 1648, Ivan Galkin built an "ostrog "on the Barguzin River which became a center for eastward expansion. In 1652, Vasily Kolesnikov reported from Barguzin that one could reach the Amur country by following the Selenga, Uda, and Khilok Rivers to the future sites of Chita and Nerchinsk. In 1653, Pyotr Beketov took Kolesnikov's route to Lake Irgen west of Chita, and that winter his man Urasov founded Nerchinsk. Next spring, he tried to occupy Nerchensk, but was forced by his men to join Stephanov on the Amur. Nerchinsk was destroyed by the local Tungus, but restored in 1658.  The Trans-Siberian Railway was built between 1896 and 1902. Construction of the scenic railway around the southwestern end of Lake Baikal required 200 bridges and 33 tunnels. Until its completion, a train ferry transported railcars across the lake from Port Baikal to Mysovaya for a number of years. The lake became the site of the minor engagement between the Czechoslovak legion and the Red Army in 1918. At times during winter freezes, the lake could be crossed on foot, though at risk of frostbite and deadly hypothermia from the cold wind moving unobstructed across flat expanses of ice. In the winter of 1920, the Great Siberian Ice March occurred, when the retreating White Russian Army crossed frozen Lake Baikal. The wind on the exposed lake was so cold, many people died, freezing in place until spring thaw. Beginning in 1956, the impounding of the Irkutsk Dam on the Angara River raised the level of the lake by.  As the railway was built, a large hydrogeographical expedition headed by F.K. Drizhenko produced the first detailed contour map of the lake bed.

Research.

Several organizations are carrying out natural research projects on Lake Baikal. Most of them are governmental or associated with governmental organizations. The Baikalian Research Centre is an independent research organization carrying out environmental educational and research projects at Lake Baikal.  In July 2008, Russia sent two small submersibles, Mir-1 and Mir-2, to descend to the bottom of Lake Baikal to conduct geological and biological tests on its unique ecosystem. Although originally reported as being successful, they did not set a world record for the deepest freshwater dive, reaching a depth of only. That record is currently held by Anatoly Sagalevich, at (also in Lake Baikal aboard a Pisces submersible in 1990). Russian scientist and federal politician Artur Chilingarov, the leader of the mission, took part in the Mir dives as did Russian leader Vladimir Putin.  Since 1993, neutrino research has been conducted at the Baikal Deep Underwater Neutrino Telescope (BDUNT). The Baikal Neutrino Telescope NT-200 is being deployed in Lake Baikal, from shore at a depth of. It consists of 192 optical modules.

Economy.

The lake, nicknamed "the Pearl of Siberia", drew investors from the tourist industry as energy revenues sparked an economic boom. Viktor Grigorov's Grand Baikal in Irkutsk is one of the investors, who planned to build three hotels, creating 570 jobs. In 2007, the Russian government declared the Baikal region a special economic zone. A popular resort in Listvyanka is home to the seven-story Hotel Mayak. At the northern part of the lake, Baikalplan (a German NGO) built together with Russians in 2009 the Frolikha Adventure Coastline Track, a -long long-distance trail as example for a sustainable development of the region. Baikal was also declared a UNESCO World Heritage site in 1996. Rosatom plans to build a laboratory near Baikal, in conjunction with an international uranium plant and to invest $2.5 billion in the region and create 2,000 jobs in the city of Angarsk.  Lake Baikal is a popular destination among tourists from all over the world. According to the Russian Federal State Statistics Service, in 2013, 79,179 foreign tourists visited Irkutsk and Lake Baikal; in 2014, 146,937 visitors. The most popular places to stay by the lake are Listvyanka village, Olkhon Island, Kotelnikovsky cape, Baykalskiy Priboi, resort Khakusy and Turka village. The popularity of Lake Baikal is growing from year to year, but there is no developed infrastructure in the area. For the quality of service and comfort from the visitor's point of view, Lake Baikal still has a long way to go.  The ice road to Olkhon Island is the only legal ice road on Lake Baikal. The route is prepared by specialists every year and it opens when the ice conditions allow it. In 2015, the ice road to Olkhon was open from 17 February to 23 March. The thickness of the ice on the road is about, maximum capacity allowed – ; it is open to the public from 9 am to 6 pm. The road through the lake is long and it goes from the village Kurkut on the mainland, to Irkutskaya Guba on Olkhon Island.

Ecotourism.

Baikal has a number of different tourist activities, depending on season. Generally Baikal has two top tourist seasons. The first season is ice season, which starts usually in mid-January and lasts till mid-April. During this season ice depth increases up to 140 centimeters, that allows quite safe vehicle driving on the ice cover (except heavy vehicles, such as tourist buses, that do not take this risk). This allows access to the figures of ice that are formed at rocky banks of Olkhon Island, including Cape Hoboy, the Three Brothers rock, and caves to the North of Khuzhir. It also provides access to small islands like Ogoy Island and Zamogoy.  The ice itself has a transparency of one meter depth, having different patterns of crevasses, bubbles, and sounds. That is why this season is popular for hiking, ice-walking, ice-skating, and bicycle-riding. An ice route around Olkhon is around 200 km. Some tourists may spot a Baikal seal along the route. Local entrepreneurs offer overnight in Yurt on ice. Also this season attracts fans of ice fishing. This activity is most popular on Buryatia side of Baikal (Ust-Barguzin). Non-fishermen may try fresh Baikal fresh fish on local markets in villages (Listvyanka, Ust-Barguzin).  The ice season ends in mid-April. Owing to increasing temperatures ice starts to melt and becomes shallow and fragile, especially in places with strong under-ice flows. Vehicles and people start to fall under ice. This leads to many casualties every year.  Second tourist season is summer, which lets tourists dive deeper into virgin Baikal nature. Hiking trails become open, many of them cross two mountain ranges: Baikal Range on the western side and Barguzin Range on the eastern side of Baikal. The most popular trail starts in Listvyanka and goes along the Baikal coast to Bolshoye Goloustnoye. The total length of the route is 55 km, but the most part of tourists usually take only a part of it – a section of 25 km to Bolshie Koty. It has a lower difficulty level and could be passed by people without special skills and gear.  Small tourist vessels operate in the area, availing bird-watching, animal watching (especially Baikal seal), and fishing. Water in the lake stays extremely cold in most places (does not exceed 10 C most of the year), but in few gulfs like Chivirkuy it can be comfortable for swimming.  Olkhon's most-populated village Khuzhir is an ecotourist destination. Baikal has always been popular in Russia and CIS-countries, but for the last few years Baikal has seen an influx of visitors from China and Europe.

Environmental concerns.

Lake Baikal faces a series of detrimental phenomenon including the disappearance of the omul fish, rapid growth of putrid algae and the death of endemic species of sponges across its area.

Baykalsk Pulp and Paper Mill.

The Baykalsk Pulp and Paper Mill was constructed in 1966, directly on the shoreline of Lake Baikal. The plant bleached paper using chlorine and discharged waste directly into Lake Baikal. The decision to construct the plant on the Lake Baikal resulted in strong protests from Soviet scientists; according to them, the ultra-pure water of the lake was a significant resource and should have been used for innovative chemical production (for instance, the production of high-quality viscose for the aeronautics and space industries). The Soviet scientists felt that it was irrational to change Lake Baikal's water quality by beginning paper production on the shore. It was their position that it was also necessary to preserve endemic species of local biota, and to maintain the area around Lake Baikal as a recreation zone. However, the objections of the Soviet scientists faced opposition from the industrial lobby and only after decades of protest, the plant was closed in November 2008 due to unprofitability. In March 2009, the plant owner announced the paper mill would never reopen. However, on 4 January 2010, production was resumed. Later that year on 13 January 2010, Russian Federation President Vladimir Putin introduced changes in the legislation legalising the operation of the plant; this action brought about a wave of protests from ecologists and local residents. These changes were based on the determination President Putin made through a visual verification of Lake Baikal's condition from a miniature submarine, "I could see with my own eyes – and scientists can confirm – Baikal is in good condition and there is practically no pollution". Despite this, in September 2013, the mill underwent a final bankruptcy, with the last 800 workers slated to lose their jobs by 28 December 2013. On the day the plant was to close, 28 December 2013, the Russian government announced plans to build the Russian Nature Reserve's Expo Center in place of the closed paper mill.

Cancelled East Siberia-Pacific Ocean oil pipeline.

Russian oil pipelines state company Transneft was planning to build a trunk pipeline that would have come within of the lake shore in a zone of substantial seismic activity. Environmental activists in Russia, Greenpeace, Baikal pipeline opposition and local citizens were strongly opposed to these plans, due to the possibility of an accidental oil spill that might cause significant damage to the environment. According to the Transneft's president, numerous meetings with citizens near the lake were held in towns along the route, especially in Irkutsk. Transneft agreed to alter its plans when Russian president Vladimir Putin ordered the company to consider an alternative route to the north to avoid such ecological risks. Transneft has since decided to move the pipeline away from Lake Baikal, so that it will not pass through any federal or republic natural reserves. Work began on the pipeline two days after President Putin agreed to changing the route away from Lake Baikal.

Proposed uranium enrichment centre.

In 2006, the Russian government announced plans to build the world's first international uranium enrichment center at an existing nuclear facility in Angarsk, a city on the river Angara some downstream from the lake's shores. Critics and environmentalists argued it would be a disaster for the region and are urging the government to reconsider.  After enrichment, only 10% of the uranium-derived radioactive material would be exported to international customers, leaving 90% near the Lake Baikal region for storage. Uranium tailings contain radioactive and toxic materials, which if improperly stored, are potentially dangerous to humans and can contaminate rivers and lakes.  An enrichment center was constructed in the 2010s.

Chinese owned bottled water plant.

Chinese owned AquaSib has been purchasing land along the lake and started building a bottling plant and pipeline in the town of Kultuk. The goal was to export 190 million liters of water to China even though the lake had been experiencing historically low water levels. This spurred protests by the local population that the lake would be drained of its water, at which point the local government halted the plans pending analysis.

Other pollution sources.

According to "The Moscow Times" and "Vice", an increasing number of an invasive species of algae thrives in the lake from hundreds of tons of liquid waste, including fuel and excrement, regularly disposed into the lake by tourist sites, and up to 25,000 tons of liquid waste are disposed of every year by local ships.

Historical traditions.

The first European to reach the lake is said to have been Kurbat Ivanov in 1643.  In the past, the Baikal was referred to by many Russians as the "Baikal Sea" (, "More Baikal"), rather than merely "Lake Baikal" (, "Ozero Baikal"). This usage is attested already in the "Life" of Protopope Avvakum (1621–1682), and on the late-17th-century maps by Semyon Remezov. It is also attested in the famous song, now passed into the tradition, that opens with the words "Славное море, священный Байкал" (Glorious sea, [the] sacred Bajkal). To this day, the strait between the western shore of the Lake and the Olkhon Island is called "Maloye More" (Малое Море), i.e. "the Little Sea".  Lake Baikal is nicknamed "Older sister of Sister Lakes (Lake Khövsgöl and Lake Baikal)".  According to 19th-century traveler T. W. Atkinson, locals in the Lake Baikal Region had the tradition that Christ visited the area: The people have a tradition in connection with this region which they implicitly believe. They say "that Christ visited this part of Asia and ascended this summit, whence he looked down on all the region around. After blessing the country to the northward, he turned towards the south, and looking across the Baikal, he waved his hand, exclaiming 'Beyond this there is nothing.'" Thus they account for the sterility of Daouria, where it is said "no corn will grow." Lake Baikal has been celebrated in several Russian folk songs. Two of these songs are well known in Russia and its neighboring countries, such as Japan.  The latter song was a secondary theme song for the Soviet Union's second color film, "Ballad of Siberia" (1947; in ).  Martin Cruz Smith: "Siberian Dilemma," Simon & Schuster, 2019

Lake Baikal (; ;, "Baigal nuur") is a rift lake located in southern Siberia, Russia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast.

Bajkal (rusky "Байкал, Bajkal," burjatsky "Байгал, Bajgal") je jezero v jižní části východní Sibiře, na rozhraní Burjatské republiky a Irkutské oblasti v Rusku. Je to nejstarší a nejhlubší jezero na světě. Jeho stáří se odhaduje na 25 až 30 milionů let a maximální hloubka je 1642 m.


Pre-1968.

President of Czechoslovakia and Communist Party leader Antonín Novotný and his fellow conservatives had begun taking a more repressive approach toward intellectuals and writers after the Six-Day War of June 1967. The following month, Vaculík, then still a member of the Communist Party, attended the Fourth Congress of the Union of Writers. Others in attendance included communists Pavel Kohout, Ivan Klíma, and Milan Kundera, as well as non-Party member Václav Havel. Vaculík made an inflammatory speech in which he rejected the leading role of the party as unnecessary and criticized it for its restrictive cultural policies and failure to address social issues. Havel recalled the mixed response of the fellow writers to Vaculík's remarks: on the one hand, they were "delighted that someone had spoken the truth... but [their] delight was tempered by doubts about whether direct confrontation on the political level would lead anywhere, and by fears that it could stimulate a counterattack by the power center." Novotný and his supporters did indeed try to bring the writers' union under their control after the congress, but failed. Vaculík's and other writers' speeches at the conference, with their anti-Novotný sentiments, increased the gap between the conservative Novotný supporters and more moderate members of the party leadership, a division that would contribute to Novotný's eventual fall.

The Prague Spring and the "Two Thousand Words".

Vaculík was among the most progressive members of the Communist Party and thereby more radical than Alexander Dubček, who had become Party leader in January 1968. Hence, Vaculík and others generally felt that the reforms of the April Action Programme were the minimum necessary and that they should be quickly and firmly enforced. In hopes of influencing voters in upcoming party congress elections, Vaculík released the manifesto "Two Thousand Words to Workers, Farmers, Scientists, Artists, and Everyone" in several major Prague newspapers, complete with signatures of other public figures. The date was 27 June 1968, the day after preliminary censorship was abolished by the national assembly.  In the "Two Thousand Words," Vaculík asked that the public "demand the resignation of people who have misused their power" by criticism, demonstrations, and strikes. He also expressed concern over the "recent apprehension" regarding the reforms due to "the possibility that foreign forces"—those of the Warsaw Treaty Organization—"may intervene in Czechoslovakia's internal development." If this were to happen, Vaculík argued: ...the only thing we can do is to hold our own and not indulge in any provocation. We can assure our government—with weapons if need be—as long as it does what we give it a mandate to do.

Impact of the "Two Thousand Words".

Despite the overall moderate tone and Marxist–Leninist orthodoxy, the "Two Thousand Words" called for action on the part of the public in case of military intervention and therefore denied the leading role of the party, as Vaculík's 1967 speech had. It was popular throughout Czechoslovakia with both intellectuals and workers, and its popularity only increased after the party officially condemned it. It also significantly increased the concerns of the Soviet Union. Following the "Two Thousand Words," Leonid Brezhnev's party leadership, seeing a situation similar to that in 1956 Hungary developing, used the term "counterrevolution" to describe the Prague Spring for the first time. If a counterrevolution was taking place (and the Soviet Union was increasingly disposed to categorising the events in Czechoslovakia as such, as other radicals continued to act and Dubček failed to gain their confidence), socialism as the Soviet Union saw it was threatened and invasion by Warsaw Treaty Organisation troops, as occurred 20–21 August 1968, was deemed justified. This policy of the acceptability of using force wherever socialism was thought to be threatened would become known as the Brezhnev Doctrine, and Vaculík's "Two Thousand Words" was an integral step toward this early application of it.

Vaculík as a dissident.

After Gustáv Husák came to power in 1969 and censorship increased, Vaculík (now no longer a party member) was part of the circle of dissident writers in Czechoslovakia. In 1973, he started "Edice Petlice" ("Edition Padlock"), a samizdat series that he ran until 1979. Others followed with their own series, despite harassment from the party's secret police. Some samizdat authors, including Vaculík, were also published in the west.  The core of the samizdat authors eventually developed and signed the foundation document of Charter 77; Vaculík attended the second of the planning meetings in December 1976. On 6 January 1977, Vaculík, along with Havel and Pavel Landovský, an actor, attempted to take a copy of the charter to the post office to mail to the Czechoslovak government. Their car was pulled over by the Party secret police, and all three were taken in for interrogation. Other signatories were subsequently subjected to interrogations and searches of their homes, as well.  In late 1978, however, Vaculík published the article "Remarks on Courage", a piece that helped set the tone for criticism of charterists. Of the original signatories, most were from the intelligentsia in Prague and Brno, and Vaculík and others warned against them becoming so isolated that average citizens could no longer relate to Charter 77. His criticism worked against a mythologisation of the Charter and ensured a continued discussion of its position and role.

After communism.

Vaculík continued to write; the official ban on his works was lifted in late 1989. He had a weekly column in "Lidové noviny" that featured feuilletons addressing various Czech political and cultural issues, just as much of his underground work during Communism had.

Death.

Vaculík died of natural causes at the age of 88 on 6 June 2015 in Dobřichovice, where he lived by his son.

Ludvík Vaculík (23 July 1926 – 6 June 2015) was a Czech writer and journalist. He was born in Brumov, Moravian Wallachia. A prominent samizdat writer, he was best known as the author of the "Two Thousand Words" manifesto of June 1968.

Ludvík Vaculík (23. července 1926 Brumov – 6. června 2015 Dobřichovice) byl český prozaik, fejetonista, publicista, disident, autor manifestu "Dva tisíce slov" a zakladatel samizdatové edice Petlice (zal. 1972). Byl moravský patriot, ve tvorbě občas používal rodné valašské nářečí.


History.

Mathematical analysis formally developed in the 17th century during the Scientific Revolution, but many of its ideas can be traced back to earlier mathematicians. Early results in analysis were implicitly present in the early days of ancient Greek mathematics. For instance, an infinite geometric sum is implicit in Zeno's paradox of the dichotomy. Later, Greek mathematicians such as Eudoxus and Archimedes made more explicit, but informal, use of the concepts of limits and convergence when they used the method of exhaustion to compute the area and volume of regions and solids. The explicit use of infinitesimals appears in Archimedes' "The Method of Mechanical Theorems", a work rediscovered in the 20th century. In Asia, the Chinese mathematician Liu Hui used the method of exhaustion in the 3rd century AD to find the area of a circle. Zu Chongzhi established a method that would later be called Cavalieri's principle to find the volume of a sphere in the 5th century. The Indian mathematician Bhāskara II gave examples of the derivative and used what is now known as Rolle's theorem in the 12th century.  In the 14th century, Madhava of Sangamagrama developed infinite series expansions, like the power series and the Taylor series, of functions such as sine, cosine, tangent and arctangent. Alongside his development of the Taylor series of the trigonometric functions, he also estimated the magnitude of the error terms created by truncating these series and gave a rational approximation of an infinite series. His followers at the Kerala School of Astronomy and Mathematics further expanded his works, up to the 16th century.  The modern foundations of mathematical analysis were established in 17th century Europe. Descartes and Fermat independently developed analytic geometry, and a few decades later Newton and Leibniz independently developed infinitesimal calculus, which grew, with the stimulus of applied work that continued through the 18th century, into analysis topics such as the calculus of variations, ordinary and partial differential equations, Fourier analysis, and generating functions. During this period, calculus techniques were applied to approximate discrete problems by continuous ones.  In the 18th century, Euler introduced the notion of mathematical function. Real analysis began to emerge as an independent subject when Bernard Bolzano introduced the modern definition of continuity in 1816, but Bolzano's work did not become widely known until the 1870s. In 1821, Cauchy began to put calculus on a firm logical foundation by rejecting the principle of the generality of algebra widely used in earlier work, particularly by Euler. Instead, Cauchy formulated calculus in terms of geometric ideas and infinitesimals. Thus, his definition of continuity required an infinitesimal change in "x" to correspond to an infinitesimal change in "y". He also introduced the concept of the Cauchy sequence, and started the formal theory of complex analysis. Poisson, Liouville, Fourier and others studied partial differential equations and harmonic analysis. The contributions of these mathematicians and others, such as Weierstrass, developed the (ε, δ)-definition of limit approach, thus founding the modern field of mathematical analysis.  In the middle of the 19th century Riemann introduced his theory of integration. The last third of the century saw the arithmetization of analysis by Weierstrass, who thought that geometric reasoning was inherently misleading, and introduced the "epsilon-delta" definition of limit. Then, mathematicians started worrying that they were assuming the existence of a continuum of real numbers without proof. Dedekind then constructed the real numbers by Dedekind cuts, in which irrational numbers are formally defined, which serve to fill the "gaps" between rational numbers, thereby creating a complete set: the continuum of real numbers, which had already been developed by Simon Stevin in terms of decimal expansions. Around that time, the attempts to refine the theorems of Riemann integration led to the study of the "size" of the set of discontinuities of real functions.  Also, "monsters" (nowhere continuous functions, continuous but nowhere differentiable functions, space-filling curves) began to be investigated. In this context, Jordan developed his theory of measure, Cantor developed what is now called naive set theory, and Baire proved the Baire category theorem. In the early 20th century, calculus was formalized using an axiomatic set theory. Lebesgue solved the problem of measure, and Hilbert introduced Hilbert spaces to solve integral equations. The idea of normed vector space was in the air, and in the 1920s Banach created functional analysis.

Important concepts.

Metric spaces.

In mathematics, a metric space is a set where a notion of distance (called a metric) between elements of the set is defined.  Much of analysis happens in some metric space; the most commonly used are the real line, the complex plane, Euclidean space, other vector spaces, and the integers. Examples of analysis without a metric include measure theory (which describes size rather than distance) and functional analysis (which studies topological vector spaces that need not have any sense of distance).  Formally, a metric space is an ordered pair formula_1 where formula_2 is a set and formula_3 is a metric on formula_2, i.e., a function  such that for any formula_6, the following holds:  By taking the third property and letting formula_11, it can be shown that formula_12 ("non-negative").

Sequences and limits.

A sequence is an ordered list. Like a set, it contains members (also called "elements", or "terms"). Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence. Most precisely, a sequence can be defined as a function whose domain is a countable totally ordered set, such as the natural numbers.  One of the most important properties of a sequence is "convergence". Informally, a sequence converges if it has a "limit". Continuing informally, a (singly-infinite) sequence has a limit if it approaches some point "x", called the limit, as "n" becomes very large. That is, for an abstract sequence ("a") (with "n" running from 1 to infinity understood) the distance between "a" and "x" approaches 0 as "n" → ∞, denoted

Main branches.

Real analysis.

Real analysis (traditionally, the theory of functions of a real variable) is a branch of mathematical analysis dealing with the real numbers and real-valued functions of a real variable. In particular, it deals with the analytic properties of real functions and sequences, including convergence and limits of sequences of real numbers, the calculus of the real numbers, and continuity, smoothness and related properties of real-valued functions.

Complex analysis.

Complex analysis, traditionally known as the theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers. It is useful in many branches of mathematics, including algebraic geometry, number theory, applied mathematics; as well as in physics, including hydrodynamics, thermodynamics, mechanical engineering, electrical engineering, and particularly, quantum field theory.  Complex analysis is particularly concerned with the analytic functions of complex variables (or, more generally, meromorphic functions). Because the separate real and imaginary parts of any analytic function must satisfy Laplace's equation, complex analysis is widely applicable to two-dimensional problems in physics.

Functional analysis.

Functional analysis is a branch of mathematical analysis, the core of which is formed by the study of vector spaces endowed with some kind of limit-related structure (e.g. inner product, norm, topology, etc.) and the linear operators acting upon these spaces and respecting these structures in a suitable sense. The historical roots of functional analysis lie in the study of spaces of functions and the formulation of properties of transformations of functions such as the Fourier transform as transformations defining continuous, unitary etc. operators between function spaces. This point of view turned out to be particularly useful for the study of differential and integral equations.

Differential equations.

A differential equation is a mathematical equation for an unknown function of one or several variables that relates the values of the function itself and its derivatives of various orders. Differential equations play a prominent role in engineering, physics, economics, biology, and other disciplines.  Differential equations arise in many areas of science and technology, specifically whenever a deterministic relation involving some continuously varying quantities (modeled by functions) and their rates of change in space or time (expressed as derivatives) is known or postulated. This is illustrated in classical mechanics, where the motion of a body is described by its position and velocity as the time value varies. Newton's laws allow one (given the position, velocity, acceleration and various forces acting on the body) to express these variables dynamically as a differential equation for the unknown position of the body as a function of time. In some cases, this differential equation (called an equation of motion) may be solved explicitly.

Measure theory.

A measure on a set is a systematic way to assign a number to each suitable subset of that set, intuitively interpreted as its size. In this sense, a measure is a generalization of the concepts of length, area, and volume. A particularly important example is the Lebesgue measure on a Euclidean space, which assigns the conventional length, area, and volume of Euclidean geometry to suitable subsets of the formula_14-dimensional Euclidean space formula_15. For instance, the Lebesgue measure of the interval formula_16 in the real numbers is its length in the everyday sense of the word – specifically, 1.  Technically, a measure is a function that assigns a non-negative real number or +∞ to (certain) subsets of a set formula_17. It must assign 0 to the empty set and be (countably) additive: the measure of a 'large' subset that can be decomposed into a finite (or countable) number of'smaller' disjoint subsets, is the sum of the measures of the "smaller" subsets. In general, if one wants to associate a "consistent" size to "each" subset of a given set while satisfying the other axioms of a measure, one only finds trivial examples like the counting measure. This problem was resolved by defining measure only on a sub-collection of all subsets; the so-called "measurable" subsets, which are required to form a formula_18-algebra. This means that countable unions, countable intersections and complements of measurable subsets are measurable. Non-measurable sets in a Euclidean space, on which the Lebesgue measure cannot be defined consistently, are necessarily complicated in the sense of being badly mixed up with their complement. Indeed, their existence is a non-trivial consequence of the axiom of choice.

Numerical analysis.

Numerical analysis is the study of algorithms that use numerical approximation (as opposed to general symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics).  Modern numerical analysis does not seek exact answers, because exact answers are often impossible to obtain in practice. Instead, much of numerical analysis is concerned with obtaining approximate solutions while maintaining reasonable bounds on errors.  Numerical analysis naturally finds applications in all fields of engineering and the physical sciences, but in the 21st century, the life sciences and even the arts have adopted elements of scientific computations. Ordinary differential equations appear in celestial mechanics (planets, stars and galaxies); numerical linear algebra is important for data analysis; stochastic differential equations and Markov chains are essential in simulating living cells for medicine and biology.

Applications.

Techniques from analysis are also found in other areas such as:

Physical sciences.

The vast majority of classical mechanics, relativity, and quantum mechanics is based on applied analysis, and differential equations in particular. Examples of important differential equations include Newton's second law, the Schrödinger equation, and the Einstein field equations.  Functional analysis is also a major factor in quantum mechanics.

Signal processing.

When processing signals, such as audio, radio waves, light waves, seismic waves, and even images, Fourier analysis can isolate individual components of a compound waveform, concentrating them for easier detection or removal. A large family of signal processing techniques consist of Fourier-transforming a signal, manipulating the Fourier-transformed data in a simple way, and reversing the transformation.

Other areas of mathematics.

Techniques from analysis are used in many areas of mathematics, including:

Mathematical analysis is the branch of mathematics dealing with limits and related theories, such as differentiation, integration, measure, infinite series, and analytic functions.

Matematická analýza ( [] „řešení“, starořecky ἀναλύειν "ánalýein" „řešit“) je jednou ze základních disciplín matematiky. Jejími základními pojmy jsou funkce, limita (posloupností a funkcí), derivace a integrál. Zahrnuje však také teorii míry, nekonečných řad a analytických funkcí. Metody matematické analýzy mají velký význam v přírodních a technických vědách. Základy matematické analýzy (infinitezimální počet) se zejména v anglosaských zemích označují jako calculus, kalkul(us), což se po roce 2000 prosazuje někde i do češtiny. (Existuje však i logický kalkulus.) Toto označení pochází z latinského slova "calculus", oblázek. Ve starověkém Římě se oblázky používaly v abacích, což byly desky s drážkami, ve kterých se kaménky posunovaly obdobně jako korálky na drátěném počítadle.


Formal definition.

In giving a formal definition of Boolean circuits, Vollmer starts by defining a basis as set "B" of Boolean functions, corresponding to the gates allowable in the circuit model. A Boolean circuit over a basis "B", with "n" inputs and "m" outputs, is then defined as a finite directed acyclic graph. Each vertex corresponds to either a basis function or one of the inputs, and there is a set of exactly "m" nodes which are labeled as the outputs. The edges must also have some ordering, to distinguish between different arguments to the same Boolean function.  As a special case, a propositional formula or Boolean expression is a Boolean circuit with a single output node in which every other node has fan-out of 1. Thus, a Boolean circuit can be regarded as a generalization that allows shared subformulas and multiple outputs.  A common basis for Boolean circuits is the set {AND, OR, NOT}, which is functionally complete, i. e. from which all other Boolean functions can be constructed.

Computational complexity.

Background.

A particular circuit acts only on inputs of fixed size. However, formal languages (the string-based representations of decision problems) contain strings of different lengths, so languages cannot be fully captured by a single circuit (in contrast to the Turing machine model, in which a language is fully described by a single Turing machine). A language is instead represented by a "circuit family". A circuit family is an infinite list of circuits formula_1, where formula_2 has formula_3 input variables. A circuit family is said to decide a language formula_4 if, for every string formula_5, formula_5 is in the language formula_4 if and only if formula_8, where formula_3 is the length of formula_5. In other words, a language is the set of strings which, when applied to the circuits corresponding to their lengths, evaluate to 1.

Complexity measures.

Several important complexity measures can be defined on Boolean circuits, including circuit depth, circuit size, and number of alternations between AND gates and OR gates. For example, the size complexity of a Boolean circuit is the number of gates.  It turns out that there is a natural connection between circuit size complexity and time complexity. Intuitively, a language with small time complexity (that is, requires relatively few sequential operations on a Turing machine), also has a small circuit complexity (that is, requires relatively few Boolean operations). Formally, it can be shown that if a language is in formula_11, where formula_12 is a function formula_13, then it has circuit complexity formula_14.

Complexity classes.

Several important complexity classes are defined in terms of Boolean circuits. The most general of these is P/poly, the set of languages that are decidable by polynomial-size circuit families. It follows directly from the fact that languages in formula_11 have circuit complexity formula_14 that Pformula_17P/poly. In other words, any problem that can be computed in polynomial time by a deterministic Turing machine can also be computed by a polynomial-size circuit family. It is further the case that the inclusion is proper (i.e. Pformula_18P/poly) because there are undecidable problems that are in P/poly. P/poly turns out to have a number of properties that make it highly useful in the study of the relationships between complexity classes. In particular, it is helpful in investigating problems related to P versus NP. For example, if there is any language in NP that is not in P/poly then Pformula_19NP. P/poly also helps to investigate properties of the polynomial hierarchy. For example, if NP ⊆ P/poly, then PH collapses to formula_20. A full description of the relations between P/poly and other complexity classes is available at "Importance of P/poly". P/poly also has the interesting feature that it can be equivalently defined as the class of languages recognized by a polynomial-time Turing machine with a polynomial-bounded advice function.  Two subclasses of P/poly that have interesting properties in their own right are NC and AC. These classes are defined not only in terms of their circuit size but also in terms of their "depth". The depth of a circuit is the length of the longest directed path from an input node to the output node. The class NC is the set of languages that can be solved by circuit families that are restricted not only to having polynomial-size but also to having polylogarithmic depth. The class AC is defined similarly to NC, however gates are allowed to have unbounded fan-in (that is, the AND and OR gates can be applied to more than two bits). NC is an important class because it turns out that it represents the class of languages that have efficient parallel algorithms.

Circuit evaluation.

The Circuit Value Problem — the problem of computing the output of a given Boolean circuit on a given input string — is a P-complete decision problem. Therefore, this problem is considered to be "inherently sequential" in the sense that there is likely no efficient, highly parallel algorithm that solves the problem.

In computational complexity theory and circuit complexity, a Boolean circuit is a mathematical model for combinational digital logic circuits. A formal language can be decided by a family of Boolean circuits, one circuit for each possible input length. Boolean circuits are also used as a formal model for combinational logic in digital electronics.

Logický, číslicový či digitální obvod je elektronický obvod, který pracuje s diskrétními stavy. Jsou tvořeny tzv. logickými členy (nazývanými též hradla). Naopak z logických obvodů se skládají číslicové systémy.


Early life.

Donovan was born on 10 May 1946, in Maryhill, Glasgow, to Donald and Winifred (née Philips) Leitch. His grandmothers were Irish. He contracted polio as a child. The disease and treatment left him

Music career.

1964–65: Rise to fame.

Returning to Hatfield, Donovan spent several months playing in local clubs, absorbing the folk scene around his home in St Albans, learning the crosspicking guitar technique from local players such as Mac MacLeod and Mick Softley and writing his first songs. In 1964, he travelled to Manchester with Gypsy Dave, then spent the summer in Torquay, Devon. In Torquay he stayed with Mac MacLeod and took up busking, studying the guitar, and learning traditional folk and blues.  In late 1964, Donovan was offered a management and publishing contract by Peter Eden and Geoff Stephens of Pye Records in London, for which he recorded a 10-track demo tape (later released on iTunes), which included the original of his first single, "Catch the

Donovan and Dylan.

During Bob Dylan's trip to the UK in the spring of 1965, the British music press were making comparisons of the two singer-songwriters and going so far as to stir up allegations of a rivalry, and other luminaries of the pop scene were chiming in. The Rolling Stones guitarist Brian Jones said,  Donovan is the undercurrent In D. A. Pennebaker's film "Dont Look Back" documenting Dylan's tour. Near the start of the film, Dylan opens a newspaper and exclaims, "Donovan? Who is this Donovan?" and his associates spur the rivalry on by telling Dylan that Donovan is a better guitar player, but that he had only been around for three months. Throughout the film Donovan's name is seen next to Dylan's on newspaper headlines and on posters in the background, and Dylan and his friends refer to him consistently.

Collaboration with Mickie Most.

In late 1965, Donovan split with his original management and signed with Ashley Kozak, who was working for Brian Epstein's NEMS Enterprises. Kozak introduced Donovan to American businessman Allen Klein (later manager of the Rolling Stones and in their final waning months, the Beatles). Klein in turn introduced Donovan to producer Mickie Most, who had chart-topping productions with the Animals, Lulu, and Herman's Hermits. Most produced all Donovan's recordings during this period, although Donovan said in his autobiography

"Sunshine Superman".

By 1966, Donovan had shed the Dylan/Guthrie influences and become one of the first British pop musicians to adopt flower power. He immersed himself in jazz, blues, Eastern music, and the new generation of counterculture-era US West Coast bands such as Jefferson Airplane and the Grateful Dead. He was entering his most creative phase as a songwriter and recording artist, working with Mickie Most and with arranger, musician, and jazz fan John Cameron. Their first collaboration was "Sunshine Superman", one of the first psychedelic pop records.  Donovan's rise stalled in December 1965 when "Billboard" broke news of the impending production deal between Klein, Most, and Donovan, and then reported that Donovan was to sign with Epic Records in the US. Despite Kozak's denials, Pye Records dropped

Mellow Yellow.

On 24 October 1966, Epic released the single "Mellow Yellow", arranged by John Paul Jones and purportedly featuring Paul McCartney on backing vocals, but not in the chorus. In his autobiography Donovan explained "electrical banana" was a reference to a "yellow-coloured vibrator". The song became Donovan's signature tune in the US and reached No. 2 on the Billboard Hot 100, No. 3 on the Cash Box chart, and earned a gold record award for sales of more than one million in the US.  Through the first half of 1967, Donovan worked on a double-album studio project, which he produced. In January he gave a concert at the Royal Albert Hall accompanied by a ballerina who danced during a 12-minute

Arrest.

In mid-1966, Donovan became the first high-profile British pop star to be arrested for possession of cannabis. Donovan's drug use was mostly restricted to cannabis, with occasional use of LSD and mescaline. His LSD use is thought to be referenced indirectly in some of his lyrics. Public attention was drawn to his marijuana use by the TV documentary "A Boy Called Donovan" in early 1966, which showed the singer and friends smoking cannabis at a party thrown by the film crew. Donovan's arrest proved to be the first in a long series involving the Beatles and the Rolling Stones. In early 1967, Donovan was subject of an exposé in the "News of the World".  According to Donovan, the article was based on an interview by an ex-girlfriend of his friend Gypsy Dave.

1967–69: International success.

In July 1967, Epic released "There Is a Mountain", which just missed the US top ten and was later used as the basis for the Allman Brothers Band's "Mountain Jam". In September, Donovan toured the US, backed by a jazz group and accompanied by his father, who introduced the show. Later that month, Epic released Donovan's fifth album, a set entitled, "A Gift from a Flower to a Garden", the first rock music box set and only the third pop-rock double album released. It was split into halves. The first, "Wear Your Love Like Heaven", was for people of his generation who would one day be parents; the second, "For Little Ones", was songs Donovan had written for coming generations. Worried it might be a poor seller, Epic boss Clive Davis also insisted the albums be split and sold separately in the US (the "Wear Your Love Like Heaven" album cover was photographed at Bodiam Castle), but his fears were unfounded – although it took time, the original boxed set sold steadily, eventually peaking at 19 in the US album chart and achieving gold record status in the US in early 1970.  The psychedelic and mystical overtones were unmistakable – the front cover featured an infra-red photograph by Karl Ferris showing Donovan in a robe holding flowers and peacock feathers, while the back photo showed him holding hands with

1970s: Changes.

In late 1969, the relationship with Most ended after an argument over

Open Road band.

Donovan said he wanted to record with someone else, and he and Most did not work together again until "Cosmic Wheels" (1973). After the rift, Donovan spent two months writing and recording the album "Open Road" as a member of the rock trio Open Road. Stripping the sound of Most's heavy studio productions down to stuff that could be played by a live band, Donovan dubbed the sound, "Celtic Rock". The album peaked at No. 16 in the US, the third highest of any of his full-length releases to date, but as his concert appearances became less frequent and new artists and styles of popular music began to emerge, his commercial success began to decline. Donovan said:  I was exhausted and looking for roots and new directions. I checked into Morgan Studios in London and stayed a long while creating Open Road and the "HMS Donovan" sessions. Downstairs was McCartney, doing

Reunions with Linda Lawrence and Mickie Most.

After this reunion, Donovan and Linda married on 2 October 1970 at Windsor register office and honeymooned in the Caribbean. Donovan dropped out of the round of tour promotion and concentrated on writing, recording and his family. The largely self-produced children's album "HMS Donovan" in 1971, went unreleased in the US and did not gain a wide audience. During an 18-month tax exile in Ireland (1971–72), he wrote for the 1972 film "The Pied Piper" in the title role, and for "Brother Sun, Sister Moon" (1972). The title song from the Zeffirelli film provided Donovan with a publishing windfall in 1974 when it was covered as the B-side of the million-selling US top 5 hit "The Lord's Prayer", by Australia's singing nun, Sister Janet Mead.  After a new deal with Epic, Donovan reunited with Mickie Most

1980s: occasional appearances.

The punk era (1976–1980) provoked a backlash in Britain against the optimism and whimsy of the hippie era, of which Donovan was a prime example. The word "hippie" became pejorative, and Donovan's fortunes suffered. In this period he released the albums "Neutronica" (1980), "Love Is Only Feeling" (1981), and "Lady of the Stars" (1984), and guest-starred on "Stars on Ice", a half-hour

1990s: a retrospective decade.

In 1990 Donovan released a live album featuring new performances of his classic songs. A tribute album to Donovan, "Island of Circles", was released by Nettwerk in 1991. Sony's 2-CD boxed set "" (1992) continued the restoration of

2000s.

In 2000, Donovan narrated and played himself in the "Futurama" episode "The Deep South" on 16 April with a parody of the song "Atlantis".  A new album, "Beat Cafe", on Appleseed Records in 2004, marked a return to the jazzy sound of his 1960s recordings and featured bassist Danny Thompson and drummer Jim Keltner, with production by John Chelew (Blind Boys of Alabama). At a series of "Beat Cafe" performances in New York, Richard Barone (The Bongos) joined Donovan to sing and

Family.

Donovan had a relationship with American model Enid Karl, and they had two children: actor-musician Donovan Leitch in 1967, and actress Ione Skye in 1970.  Donovan married Linda Lawrence in October 1970. They have two children together, Astrella and

Accolades.

In November 2003, Donovan was awarded an honorary degree of Doctor of Letters from the University of Hertfordshire. He was nominated by Sara Loveridge (who was a student at the University and had interviewed and reviewed Donovan for the university paper in 2001–2002), Andrew Morris, Sara's partner and Donovan researcher/writer and co-nominated by Mac MacLeod.  On 14 April 2012 Donovan was inducted in the Rock and Roll Hall of Fame.

Donovan Philips Leitch (born 10 May 1946) is a Scottish singer, songwriter and guitarist. He developed an eclectic and distinctive style that blended folk, jazz, pop, psychedelia, and world music (notably calypso). He has lived in Scotland, Hertfordshire (England), London, California, and since at least 2008 in County Cork, Ireland, with his family. Emerging from the British folk scene, Donovan reached fame in the United Kingdom in early 1965 with live performances on the pop TV series "Ready Steady Go!".

Donovan Phillip Leitch (* 10. května 1946) je skotský zpěvák a básník. Narodil se v Glasgow, ale v roce 1956 se přestěhoval do Anglie. Do svých zhruba 15 let byl bezproblémové dítě, kolem tohoto roku začal utíkat z domova.


Geography.

Adygea lies in Russia's Southern Federal District of Eastern Europe, in the foothills of the Northwestern Caucasus in the Caucasus Mountains System, with plains in the northern areas and mountains in the southern area. Forests (mainly of European beech, oak, and maple) cover almost 40% of its territory.

Rivers.

The long Kuban River is one of the major navigable rivers in the Caucasus region. It forms part of the northern border between the Republic of Adygea and Krasnodar Krai. Other rivers include:

Lakes.

The republic has no large lakes. However, the several large reservoirs include:

Mountains.

The republic's major mountains and peaks range in height from, and include:

Natural resources.

The republic is rich in oil and natural gas. Other natural resources include gold, silver, tungsten, and iron.

Climate.

February 15, 2010 recorded the absolute maximum for the winter months—in the capital, the city of Maykop, the temperature was.

History.

The Cherkess (Adyghe) Autonomous Oblast was established within the Russian SFSR on July 27, 1922, on the territories of the Kuban-Black Sea Oblast, primarily settled by the Adyghe people. At that time, Krasnodar was the administrative center. It was renamed Adyghe (Cherkess) Autonomous Oblast on August 24, 1922, soon after its creation. In the first two years of its existence the autonomous oblast was a part of the Russian SFSR, but on October 17, 1924, it was transferred to the jurisdiction of the newly created North Caucasus Krai within the RSFSR.  It was renamed Adyghe Autonomous Oblast (AO) in July 1928. On January 10, 1934, the autonomous oblast became part of the new Azov-Black Sea Krai, which was removed from North Caucasus Krai. Maykop was made the administrative center of the autonomous oblast in 1936. Adyghe AO became part of Krasnodar Krai when it was established on September 13, 1937.  On July 3, 1991, the oblast was elevated to the status of a republic under the jurisdiction of the Russian Federation. The first President of the republic was Aslan Dzharimov, elected on 5 January 1992.  Relations between the Adyghe and ethnic Russians in Adygea are currently good. Russians make up two-thirds of the population within Adygea. The current Head of Adygea is Murat Kumpilov.

Divisions.

The Republic of Adygea is administratively divided into seven districts ("raions"), two cities/towns, and (at a lower administrative level) five urban-type settlements. Municipally, the republic is divided into two urban okrugs, five urban settlements, and 46 rural settlements.

Demographics.

Ethnic groups.

According to the 2010 Census, ethnic Russians make up 63.6% of the republic's total population, while the ethnic Adyghe are 25.8%. Other groups include Armenians (3.7%), Ukrainians (1.4%), Kurds (1.1%) and Tatars (0.6%).

Religions.

According to a 2012 survey which interviewed 56,900 people, 35.4% of the population of Adygea adheres to the Russian Orthodox Church, 12.6% to Islam, 3% are unaffiliated Christians and 1% are Orthodox Christian believers who don't belong to church or are members of other Orthodox churches. In addition, 30% of the population declares to be "spiritual but not religious", 9% is atheist, and 8.6% follows other religions or did not answer to the question.

Politics.

The chief executive of the government of the Republic of Adygea is the Head (called "President" until May 2011), who is appointed for a five-year term. Proficiency in the Adyghe language is a prerequisite for the candidate.  The current Head, Murat Kumpilov (since January 27, 2017), succeeded Aslan Tkhakushinov, initially as acting Head of the region. There is also a directly elected State Council ("Khase" or "Xase"—not to be confused with the Adyghe Khase, a union of Adyghe who supported Sovmen for a second term), which comprises the Council of Representatives and the Council of the Republic. Both councils are elected every five years and have 27 deputies each.  The Republic sends three representatives to the parliament of the Russian Federation; one to the State Duma and the other two to the Federation Council.  The Constitution of the Republic of Adygea was adopted on May 14, 1995.

Economy.

Even though it is one of the poorest parts of Russia, the republic has abundant forests and rich soil. The region is famous for producing grain, sunflowers, tea, tobacco, and other produce. Hog and sheep breeding are also developed.  Food, timber, woodworking, pulp and paper, heavy engineering, and metal-working are the most developed industries.

Transportation.

There is a small airport in Maykop (ICAO airport code URKM). Several rail lines pass through the republic.

Culture.

The Adyghe language (Адыгабзэ) is a member of the isolate Northwest Caucasian language family. Along with Russian, Adyghe is the official language of the republic.  There are 8 state and 23 public museums in the republic. The largest museum is the National Museum of the Republic of Adygea in Maykop.

Education.

Adyghe State University and Maykop State Technological University, both in the capital Maykop, are the two major higher education facilities in Adygea.

The Republic of Adygea (; ;, "Adygæ Respublik"), also known as the Adyghe Republic, is a federal subject (a republic) of Russia. It is geographically located in the North Caucasus region of European Russia, and is part of the Southern Federal District. Adygea covers an area of, the fifth-smallest Russian federal subject by area, with its territory an enclave within Krasnodar Krai. Adygea has a population of 439,996 (2010 Census).

Adygejská republika neboli Adygejsko je republika Ruské federace, tvořící enklávu v Krasnodarském kraji v jihozápadní části země, v historickém regionu Kubáň poblíž Černého moře. Má rozlohu pouze 7 600 km2 a čítá 447 000 obyvatel. Hlavním městem je Majkop.


Plot summary.

The Ankh-Morpork City Watch is expanding; there is now a Traffic department with traffic cameras implemented using iconograph technomancy and a wheel clamping team, and the clacks are beginning to replace homing pigeons for communications between officers. The Watch is also investigating the theft of the replica Scone of Stone (a parody of the real-life Stone of Scone) from the Ankh-Morpork Dwarf Bread Museum. (The Scone of Stone in the novel is kept under close guard in a dwarf mine in Überwald, and will form a vital part of the forthcoming coronation ceremony of the dwarfs' new Low King.)  Samuel Vimes, Commander of the Ankh-Morpork City Watch and Duke of Ankh, is sent to the remote region of Überwald as an ambassador to take advantage of the coronation to negotiate with the new Low King on increased imports of fat. (Underground fat deposits are abundant in Überwald as a fifth Discworld-supporting elephant impacted there in prehistoric times, according to legend.)  Überwald is also the traditional home of the Disc's dwarfs who are about to enthrone a new Low King. A cabal of local werewolves seek to exploit this opportunity to destabilize the already deeply divided dwarf society. They instigate the apparent theft of the real Scone of Stone from its closely guarded cave, hoping to cause a civil war between traditionalists and progressive dwarfs and isolate the country under the werewolves' feudal leadership.  In his official capacity as ambassador Vimes meets the leaders of the local vampires, werewolves and dwarfs, starting to investigate the planned putsch along the way. Meanwhile, back in Ankh-Morpork, Angua, alerted by another wolf, learns that her werewolf brother Wolfgang is the head of the conspiracy and sets out to Überwald to stop him. Consequently, Carrot also abandons the Watch and pursues her across the country, enlisting Gaspode to follow her scent. This leaves Lord Vetinari to appoint an overburdened Colon as acting captain.  As captain, Colon becomes increasingly strict and paranoid, punishing other members of the watch for minor offences which they did not commit, such as demoting Constable Visit to Lance Constable for supposedly stealing a sugar lump. In response Corporal Nobby Nobbs sets up the Guild of Watchmen in protest. The other members of the Watch join and protest against Colon, but eventually it dwindles to just Nobby, Visit, zombie Constable Reg Shoe and golem Constable Dorfl.  The Ankh-Morpork City Watch recover the replica Scone of Stone. It is undamaged, but they suspect that someone has made a replica of the replica. In Überwald, Vimes extends his activities to include an unofficial investigation into the theft of the real Scone of Stone. He rapidly determines that the dwarfs' system of guard on it is nothing like as secure as the dwarfs think it is and that the Scone could have been stolen in a number of different ways without too much difficulty, but nevertheless later concludes that it was not in fact stolen, but destroyed in situ and its remains concealed by mixing them with the sand on the floor of the cave.  Following an attempt on the designated Low King's life, Vimes is wrongly imprisoned by the dwarfs but escapes. In the forest of the wintry countryside he is tracked by the conspiring werewolves - forced by Wolfgang into playing "the game" he must outrun the werewolves. Carrot and Angua arrive just in time to save Vimes from the murderous pack.  Vimes' wife has been taken to the castle of Angua's werewolf family, so the commander and his entourage set out to save her. Managing to defeat the power-hungry Wolfgang, they are also able to restore the Scone of Stone.  Back in their embassy the Morporkians are once more attacked by Wolfgang. In a final stand-off, he resists arrest and is killed by Commander Vimes with a Clacks flare. With the Low King's regalia returned, the enthronement ceremony finally takes place, and Vimes is granted prime rates for fat imports to Ankh-Morpork, thus fulfilling his original mission.  The book finishes with Carrot and Angua returning to Ankh-Morpork. Carrot takes back his old rank of captain, returning Colon to his duties as a sergeant and ordering him and Nobby to gather the rest of the Watch together.

The Fifth Elephant is a fantasy novel by British writer Terry Pratchett, the 24th book in the "Discworld" series. It introduces the clacks, a long-distance semaphore system. The novel was nominated for the Locus Award in 2000.

Pátý Elefant (anglicky "The Fifth Elephant") je humoristická fantasy kniha Terryho Pratchetta, 24. ze série "Zeměplocha". Jedná se o pátou knihu ze Zeměplochy, jejíž hlavní postavou je velitel Městské hlídky Samuel Elánius.


History.

Bochnia is one of the oldest cities of Lesser Poland. The first known source mentioning the city is a letter of 1198, in which Aymar the Monk, Latin Patriarch of Jerusalem, confirmed a donation by the local magnate Mikora Gryfit to the monastery of the Order of the Holy Sepulchre in Miechów. The discovery of major deposits of rock salt at the site of the present mine in 1248 led to the grant of city privileges (Magdeburg rights) on 27 February 1253 by Bolesław V the Chaste. In the original founding document, the German name of the town (Salzberg) is mentioned as well, since many Bochnia's residents were German-speaking settlers from Lower Silesia. Due to its salt mine and favourable location, Bochnia, which belonged to Kraków Voivodeship, was one of main cities of Lesser Poland. In the 14th century, during the reign of King Casimir the Great, a town hall was built, a defensive wall with four gates, a hospital and shelter for miners, and the construction of St. Nicolas Basilica began. In appreciation of Casimir's influence on the development of Bochnia, monument to him was erected in town's market square in the late 19th century. In the 15th century, a school was opened, and in 1623, Bernardine Abbey was founded in Bochnia. At that time, many pilgrims from Lesser Poland and Silesia visited the town, to see a miraculous painting of St. Mary, kept at a local Dominican church.  In 1561 Bochnia burned down in a fire and its salt deposits were depleted, leading to the town's decline. In 1655 Bochnia was captured by the Swedes, in 1657 by the Transylvanians, and in 1662, by the Cossacks. By the 1660s, there were only 54 houses still standing. In 1702, the town was destroyed in the Great Northern War. Fires caused further damage in 1709 and 1751. In 1772, Bochnia was annexed by the Austrian Empire, and remained part of Galicia until 1918. The Austrians liquidated both abbeys, and tore down the town hall together with the defensive wall. In 1867, Bochnia County was created and the town began a slow recovery spurred by construction of the Galician Railway of Archduke Charles Louis. In 1886, first public library was opened, in the late 19th century, the waterworks, and in 1913, a movie theater.  In the Second Polish Republic, Bochnia belonged to Kraków Voivodeship and was the capital of a county. The town housed a small garrison of the Polish Army, with 3rd Silesian Uhlans Regiment stationed there from 1924. On September 6/7, 1939, Bochnia was defended by several Polish units. One of the first mass executions in occupied Poland took place in the town: the Germans shot 52 Poles as a reprisal for killing two German police officers.

World War II.

At the outbreak of World War II, an estimated 3,500 Jews lived in Bochnia, comprising about 20% of the total population. During the German occupation of Poland, Bochnia was the site of a Jewish ghetto(the Bochnia Ghetto) to which Jews from surrounding areas were forced to move by the Nazis. The entire Jewish community was murdered in the Holocaust apart from 200 forced laborers employed at a plant headed by Gerhard Kurzbach, a Wehrmacht soldier, who ordered them to work overtime and thereby saved them from deportation. It is estimated that approximately 15,000 Jews were deported from Bochnia, with at least a further 1,800 killed in the town and its surroundings. About 90 Jews from Bochnia survived the war, either in hiding, in camps or in the Soviet Union. Most of them immigrated to the US, Brazil, Belgium, and Israel.  In 1944, the 12th Home Army Infantry Regiment was established in Bochnia. In April 1943, Witold Pilecki hid there after his escape from Auschwitz. In Communist Poland, Bochnia grew larger, with several villages incorporated into the town, mostly in the 1970s. In 1975, Bochnia belonged to Tarnów Voivodeship, and in 1984, a by-pass of the European route E40 was completed, redirecting the traffic from congested center of the town.  The Jewish family of Tiders expelled from Zaborowo in 1940 were murdered in Brześć with children except for their oldest son, 24-year-old Mendel Tider, who paved the road to Tamowo on German orders at the time of the killings. He escaped to Bochnia where he met Józef Langdorf from his neighbourhood. Together, they escaped back to Zaborowo and found refuge at the farm of the Mika family of six. Both survived, treated like relatives and fed for free until liberation. In 2000 the three members of the Mika family were bestowed the titles of the Righteous thanks to Mrs Langdorf from Israel. Stefan Mika was 73, and living in Kraków; the other two, father and mother, were already dead for several decades.

Landmarks.

Salt mine.

The Bochnia Salt Mine (Polish: "kopalnia soli w Bochni") is one of the oldest salt mines in the world and the oldest one in Poland and Europe. The mine was established between the 12th and 13th centuries after salt was discovered in Bochnia. The mines measure in length and in depth at 16 different levels. Deserted chambers, shafts and passages form a so-called underground town, which is now open to sightseers. The largest of the preserved chambers has been converted into a sanatorium.

Education.

Bochnia Academy of Economics ("Wyższa Szkoła Ekonomiczna w Bochni") is a privately owned collegiate-level institution of higher education in the city, founded in 2000. It grants bachelor's degrees (licencjat) in two fields of knowledge - Finance and Accounting, and Economics.

Twin towns — sister cities.

Bochnia is twinned with:

Bochnia () is a town of 29,992 inhabitants on the river Raba in southern Poland. The town lies approximately in halfway [] between Tarnów (east) and the regional capital Kraków (west). Bochnia is most noted for its salt mine, the oldest functioning in Europe, built in the 13th century. Since Poland's administrative reorganization in 1999, Bochnia has been the administrative capital of Bochnia County in Lesser Poland Voivodeship. Before reorganization it was part of Tarnów Voivodeship.

Bochnia je starobylé město na jihu Polska v Malopolském vojvodství, 40 km východně od Krakova při pravém břehu řeky Raba. Město mělo v roce 2008 29 444 obyvatel a rozlohu 30 km2.


The caves.

A hill called "Zlatý kůň" (Golden Horse) rises above the village of Koněprusy close to another hill called Kobyla (Mare), and nearby is a place called "V koníku" (In a Little Horse). A short journey westward leads to Kotýz, a karst plateau. Many legends have been woven about Kotýz and one of them tells about sacred horses used by the Celts for campaigns of war. A prehistoric settlement existed here, which, in Celtic times, some experts believe might well have served as a place of cult worship; druids possibly maintained a cult of the horse here.  Golden Horse hill conceals the most extensive cave system in Bohemia, accidentally discovered after an explosion in a nearby limestone quarry in 1950 and subsequently were made accessible for the public in 1959. Spanning two kilometers and three levels, the cave system inside the "Zlatý kůň" hill consists of passages and domed chambers interconnected by shafts developed in limestone of the Devonian age. The caves were formed by a small stream at the end of the Tertiary period, as well as by rainfall that seeped through cracks in the limestone. Rich speleothem formations were created by copious amounts of stalagmites and stalactites as well as by little sinter lakes. A tour leads visitors through the upper and middle levels, that present a chain of domed chambers, caverns and passages with dark abysses between them. The most beautiful area is deemed by experts to be the extensive Prošek chamber with its sinter "Jezírko lásky" (Little lake of love). The cave also offers the spectacular "Koněprusy Roses", a sight that cannot be found anywhere else in the world. They were formed by calcium carbonate dissolved in water, which then gradually precipitated on the walls of the underground lake in the shape of bushes, the tips of which later fell away to create an unusual formation reminiscent of rose blooms.

Findings.

In the earth filled parts of the caves paleontologists have excavated thousands of prehistoric animal bones from the Pleistocene period. Dating back 200,000 to 300,000 years, findings include the remains of the ancestors of the elephant mastodon, sabre-tooth tiger, monkey, cave bear, deer, reindeer, cave lion, woolly rhino, wolf, beaver, hyena and horse amongst others.  The fossilized bones of prehistoric humans aged about 13,000 years, stone tools and decorative objects from the early Stone Age provide evidence that prehistoric man also found refuge in the caves. A counterfeiter's workshop, since dubbed "the Mint", was discovered by pot holers on the upper level of the caves. Here from 1460 to 1470 unknown forgers made the Hussite coins bearing the symbol of the Czech lion. Instead of silver they used copper thinly covered with silver amalgam. The descended underground through a shaft near the top of the Golden Horse hill. It offers panoramic views in all directions; when the weather is fine about one-sixth of Bohemia is visible. The tour of the caves is long and lasts about one hour.

Koněprusy Caves () is a cave system in the heart of the limestone region known as Bohemian Karst, Czech Republic. It is located southwest of Prague, south of Beroun in the Central Bohemian Region. The name derives from nearby village of Koněprusy. With the length of and vertical range of, it is the largest cave system in Bohemia.

Koněpruské jeskyně se nalézají uvnitř návrší Zlatý kůň nad obcí Koněprusy v CHKO Český kras asi 5 km jižně od okresního města Beroun. Jsou chráněny jako kulturní památka ČR.


Definitions.

In a glossary of Buddhist terms, Richard Robinson et al. define sangha as:  Mahayana practitioners may use the word "sangha" as a collective term for all Buddhists, but the Theravada Pāli Canon uses the word "pariṣā" (Sanskrit "pariṣad") for the larger Buddhist community—the monks, nuns, lay men, and lay women who have taken the Three Refuges—with a few exceptions reserving "sangha" for a its original use in the Pāli Canon—the ideal ("arya") and the conventional.

Qualities of the Sangha.

The "Sangha" is the third of the Three Jewels in Buddhism. Common over all schools is that the "āryasaṅgha" is the foremost form of this third jewel. As for recognizable current-life forms, the interpretation of what is the Jewel depends on how a school defines Sangha. E.g. for many schools, monastic life is considered to provide the safest and most suitable environment for advancing toward enlightenment and liberation due to the temptations and vicissitudes of life in the world.  In Buddhism, the Buddha, the Dharma and the Sangha each are described as having certain characteristics. These characteristics are chanted either on a daily basis and/or on Uposatha days, depending on the school of Buddhism. In Theravada tradition they are a part of daily chanting:  The Sangha: The Sangha of the Blessed One's disciples (sāvakas) is:  That is, the four pairs of persons, the eight types of individuals - This Sangha of the Blessed One's disciples is:

Monastic tradition.

The Sangha was originally established by Gautama Buddha in the fifth century BCE in order to provide a means for those who wish to practice full-time in a direct and highly disciplined way, free from the restrictions and responsibilities of the household life. The Sangha also fulfils the function of preserving the Buddha’s original teachings and of providing spiritual support for the Buddhist lay-community. The Sangha has historically assumed responsibility for maintaining the integrity of the doctrine as well as the translation and propagation of the teachings of the Buddha.  The key feature of Buddhist monasticism is the adherence to the vinaya which contains an elaborate set of 227 main rules of conduct (known as "Patimokkha" in Pāli) including complete chastity, eating only before noon, and not indulging in malicious or salacious talk. Between midday and the next day, a strict life of scripture study, chanting, meditation, and occasional cleaning forms most of the duties for members of the Sangha. Transgression of rules carries penalties ranging from confession to permanent expulsion from the Sangha.

Japanese vinaya.

Saichō, the founder of the Japanese school of Tendai, decided to reduce the number of rules down to about 60 based on the Bodhisattva Precepts. In the Kamakura, many Japanese schools that originated in or were influenced by the Tendai such as Zen, Pure Land Buddhism and Nichiren Buddhism abolished traditional ordination in favor of this new model of the vinaya.

The Fourteen Precepts of the Order of Interbeing.

The Order of Interbeing, established in 1964 and associated with the Plum Village Tradition, has fourteen precepts observed by all monastics. They were written by Thích Nhất Hạnh.

Possessions.

Monks and nuns generally own a minimum of possessions due to their samaya as renunciants, including three robes, an alms bowl, a cloth belt, a needle and thread, a razor for shaving the head, and a water filter. In practice, they often have a few additional personal possessions.  Traditionally, Buddhist monks, nuns, and novices eschew ordinary clothes and wear robes. Originally the robes were sewn together from rags and stained with earth or other available dyes. The color of modern robes varies from community to community: saffron is characteristic for Theravada groups; blue, grey or brown for Mahayana Sangha members in Vietnam, maroon in Tibetan Buddhism, grey in Korea, and black in Japan.

Attitudes regarding food and work.

A Buddhist monk is a "bhikkhu" in Pali, Sanskrit "bhikṣu" while a nun is a "bhikkhuni", Sanskrit "bhikṣuṇī". These words literally mean "beggar" or "one who lives by alms", and it was traditional in early Buddhism for the Sangha to go on "alms round" for food, walking or standing quietly in populated areas with alms bowls ready to receive food offerings each day. Although in the vinaya laid down by the Buddha the Sangha was not allowed to engage directly in agriculture, this later changed in some Mahayana schools when Buddhism moved to East Asia, so that in the East Asian cultural sphere, the monastic community traditionally has engaged in agriculture. An emphasis on working for food is attributed to additional training guidelines laid down by a Chan Buddhist master, Baizhang Huaihai, notably the phrase, "A day without work is a day without food" ().  The idea that all Buddhists, especially Sangha members, practice vegetarianism is a Western misperception.  In the Pali Canon, the Buddha rejected a suggestion by Devadatta to impose vegetarianism on the Sangha. According to the Pali Texts, the Buddha ate meat as long as the animal was not killed specifically for him. The Buddha in the Pali Canon allowed Sangha members to eat whatever food is donated to them by laypeople, except that they may not eat meat if they know or suspect the animal was killed specifically for them. Consequently, the Theravada tradition does not practice strict vegetarianism, although an individual may do so as his or her personal choice.  On this question, Mahayana and Vajrayana traditions vary depending on their interpretation of their scriptures. In some Mahayana sutras, meat-eating is strongly discouraged and it is stated that the Buddha did not eat meat. In particular, East Asian Sangha members take on the Bodhisattva Precepts originating in the "Brahmajala Sutra", which has a vow of vegetarianism as part of the Triple Platform Ordination, where they receive the three sets of vows: śrāmaṇera/śrāmaṇerī (novitiate), monastic, and then Bodhisattva Precepts, whereas the Tibetan lineages transmit a tradition of Bodhisattva Precepts from Asanga's "Yogacarabhumi-sastra", which does not include a vow of vegetarianism. In some areas such as China, Korea and Vietnam the Sangha practices strict vegetarianism, while in other areas such as Japan or Tibet, they do not.  According to Mahayana sutras, Gautama Buddha always maintained that lay persons were capable of great wisdom and of reaching enlightenment. In some areas there has been a misconception that Theravada regards enlightenment to be an impossible goal for those outside the Sangha, but in Theravada suttas it is clearly recorded that the Buddha's uncle, a lay follower, reached enlightenment by hearing the Buddha's discourse, and there are many other such instances described in the Pāli Canon. Accordingly, emphasis on lay persons, as well as Sangha members, practicing the Buddhist path of morality, meditation, and wisdom is present in all major Buddhist schools.

Sangha as a general reference to Buddhist community.

Some scholars noted that "sangha" is frequently (and according to them, mistakenly) used in the West to refer to any sort of Buddhist community. The terms "parisa" and "gaṇa" are suggested as being more appropriate references to a community of Buddhists. "Pariṣā" means "following" and it refers to the four groups of the Buddha's followers: monks, nuns, laymen and laywomen. The Sanskrit term "gaṇa" has meanings of "flock, troop, multitude, number, tribe, series, class", and is usable as well in more mundane senses.  The Soka Gakkai, a new religious movement which began as a lay organization previously associated with Nichiren Shōshū in Japan, disputes the traditional definition of sangha. It interprets the meaning of the Three Jewels of Buddhism, in particular the "treasure of the Sangha," to include all people who practice Buddhism correctly, whether lay or clerical. After its excommunication in 1991, the organization re-published literature which then revised the terms such as" “Treasure of the Priesthood”" to "“The Buddhist Order”." Some, though not all, Nichiren Shu varying sects holds this position as do some progressive Mahayana movements as well.  Nichiren Shoshu Buddhism maintains the traditional definition of Sangha as the head temple priesthood collective as sole custodians and arbiters of Buddhist doctrine.

Sangha is a Sanskrit word used in many Indian languages, including Pali, meaning "association", "assembly", "company" or "community". It was historically used in a political context to denote a governing assembly in a republic or a kingdom. It is used in modern times by groups such as the political party and social movement Rashtriya Seva Sangh. It has long been commonly used by religious associations including by Jains and Sikhs.

Sangha je indické slovo (v páli a sanskrtu), které může být volně přeloženo jako "společenství" nebo "komunita". V buddhismu je používáno v několika významech. Nejběžněji je jím označována komunita ordinovaných buddhistických mnichů a buddhistických mnišek, přesněji řečeno rozlišuje se sangha mnichů a sangha mnišek. Ve svém striktním významu sangha znamená společenství probuzených žáků Buddhy nacházející se na jednom ze čtyř stupňů osvícení ("sótapanna", "sakadágámí", "anágámí" a "arahat"), v mahájáně je jím označováno společenství bódhisattvů. V tomto striktním pojetí je nazývána jako vznešená sangha ("arija sangha"). V současné době v souvislosti s šířením buddhismu do západních zemí je sanghou označována komunita lidí (laiků) společně se věnující praxi buddhismu.