Latvian Academy of Sciences
The Latvian Academy of Sciences is the official science academy of Latvia and is an association of the country's foremost scientists. The academy was founded as the Latvian SSR Academy of Sciences, it is located in Riga. The current President of the academy is Ojārs Spārītis; the Academy of Sciences edifice was built after World War II, between 1951 and 1961, collecting the necessary financing from the newly established kolkhozes in Latvia and – as further expenses increased, collecting the finances as "voluntary donations" deducted from the salaries of the Latvian rural population. The building is decorated with several hammer and sickle symbols as well as Latvian folk ornaments and motifs; the spire was decorated with a wreath and a five pointed star, removed after Latvia regained independence in 1991. Being 108 metres tall, it was the first skyscraper in the republic and was the tallest building until the construction of the Swedbank Headquarters in Latvia, at the time, one of the highest reinforced concrete buildings in the world.
The building, designed by Osvalds Tīlmanis, Vaidelotis Apsītis, Kārlis Plūksne, is a cousin to similar Stalin-era skyscrapers, which were representative of what became known as Stalinist architecture. The architecture of the skyscraper resembles many others built in the Soviet Union at the time, most notably the main building of Moscow State University. Local nicknames include the Kremlin; the view of Riga cityscape is open for public viewing from the 17th-floor balcony. The tower is located in the suburb of Maskavas Vorstadt. All-Russia Exhibition Centre Eighth Sister Hotel Leningradskaya Ministry of Foreign Affairs of Russia Red Gates Administrative Building Moscow State University Palace of the Soviets Seven Sisters Triumph Palace Warsaw Palace of Culture and Science International cooperation of the Latvian Academy of Sciences
Irbene is a ghost town in Ance parish, northwestern Latvia. In 1971, the Soviet Union established a secret radar center "Звезда" and built a settlement for military officers and their families, naming it Irbene because of nearby river Irbe; the town had a school, shop and concert halls. However, the town was not marked on maps. Only the holders of a special permit were able to access Irbene. After the withdrawal of the Soviet Army in 1993 the town became abandoned
Latvia the Republic of Latvia, is a country in the Baltic region of Northern Europe. Since its independence, Latvia has been referred to as one of the Baltic states, it is bordered by Estonia to the north, Lithuania to the south, Russia to the east, Belarus to the southeast, shares a maritime border with Sweden to the west. Latvia has 1,957,200 inhabitants and a territory of 64,589 km2; the country has a temperate seasonal climate. After centuries of Swedish and Russian rule, a rule executed by the Baltic German aristocracy, the Republic of Latvia was established on 18 November 1918 when it broke away and declared independence in the aftermath of World War I. However, by the 1930s the country became autocratic after the coup in 1934 establishing an authoritarian regime under Kārlis Ulmanis; the country's de facto independence was interrupted at the outset of World War II, beginning with Latvia's forcible incorporation into the Soviet Union, followed by the invasion and occupation by Nazi Germany in 1941, the re-occupation by the Soviets in 1944 to form the Latvian SSR for the next 45 years.
The peaceful Singing Revolution, starting in 1987, called for Baltic emancipation from Soviet rule and condemning the Communist regime's illegal takeover. It ended with the Declaration on the Restoration of Independence of the Republic of Latvia on 4 May 1990, restoring de facto independence on 21 August 1991. Latvia is a democratic sovereign state, parliamentary republic and a highly developed country according to the United Nations Human Development Index, its capital Riga served as the European Capital of Culture in 2014. Latvian is the official language. Latvia is a unitary state, divided into 119 administrative divisions, of which 110 are municipalities and nine are cities. Latvians and Livonians are the indigenous people of Latvia. Latvian and Lithuanian are the only two surviving Baltic languages. Despite foreign rule from the 13th to 20th centuries, the Latvian nation maintained its identity throughout the generations via the language and musical traditions. However, as a consequence of centuries of Russian rule and Soviet occupation, Latvia is home to a large number of ethnic Russians, some of whom have not gained citizenship, leaving them with no citizenship at all.
Until World War II, Latvia had significant minorities of ethnic Germans and Jews. Latvia is predominantly Lutheran Protestant, except for the Latgale region in the southeast, predominantly Roman Catholic; the Russian population are Eastern Orthodox Christians. Latvia is a member of the European Union, Eurozone, NATO, the Council of Europe, the United Nations, CBSS, the IMF, NB8, NIB, OECD, OSCE, WTO. For 2014, the country was listed 46th on the Human Development Index and as a high income country on 1 July 2014. A full member of the Eurozone, it began using the euro as its currency on 1 January 2014, replacing the Latvian lats; the name Latvija is derived from the name of the ancient Latgalians, one of four Indo-European Baltic tribes, which formed the ethnic core of modern Latvians together with the Finnic Livonians. Henry of Latvia coined the latinisations of the country's name, "Lettigallia" and "Lethia", both derived from the Latgalians; the terms inspired the variations on the country's name in Romance languages from "Letonia" and in several Germanic languages from "Lettland".
Around 3000 BC, the proto-Baltic ancestors of the Latvian people settled on the eastern coast of the Baltic Sea. The Balts established trade routes to Byzantium, trading local amber for precious metals. By 900 AD, four distinct Baltic tribes inhabited Latvia: Curonians, Selonians, Semigallians, as well as the Finnic tribe of Livonians speaking a Finnic language. In the 12th century in the territory of Latvia, there were 14 lands with their rulers: Vanema, Bandava, Duvzare, Megava, Pilsāts, Upmale, Sēlija, Jersika, Tālava and Adzele. Although the local people had contact with the outside world for centuries, they became more integrated into the European socio-political system in the 12th century; the first missionaries, sent by the Pope, sailed up the Daugava River in the late 12th century, seeking converts. The local people, did not convert to Christianity as as the Church had hoped. German crusaders were sent, or more decided to go on their own accord as they were known to do. Saint Meinhard of Segeberg arrived in Ikšķile, in 1184, traveling with merchants to Livonia, on a Catholic mission to convert the population from their original pagan beliefs.
Pope Celestine III had called for a crusade against pagans in Northern Europe in 1193. When peaceful means of conversion failed to produce results, Meinhard plotted to convert Livonians by force of arms. In the beginning of the 13th century, Germans ruled large parts of today's Latvia. Together with Southern Estonia, these conquered areas formed the crusader state that became known as Terra Mariana or Livonia. In 1282, the cities of Cēsis, Limbaži, Koknese and Valmiera, became part of the Hanseatic League. Riga became an important point of east-west trading and formed close cultural links with Western Europe. After the Livonian War, Livonia fell under Lithuanian rule; the southern part of Estonia and the northern part of Latvia were ceded to the Grand Duchy of Lithuania and formed into the Duchy of Livonia. Gotthard Kettler, the last Master of
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission; these include stars and galaxies, as well as new classes of objects, such as radio galaxies, quasars and masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang theory, was made through radio astronomy. Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used singularly, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis; the use of interferometry allows radio astronomy to achieve high angular resolution, as the resolving power of an interferometer is set by the distance between its components, rather than the size of its components.
Before Jansky observed the Milky Way in the 1930s, physicists speculated that radio waves could be observed from astronomical sources. In the 1860s, James Clerk Maxwell's equations had shown that electromagnetic radiation is associated with electricity and magnetism, could exist at any wavelength. Several attempts were made to detect radio emission from the Sun including an experiment by German astrophysicists Johannes Wilsing and Julius Scheiner in 1896 and a centimeter wave radiation apparatus set up by Oliver Lodge between 1897 and 1900; these attempts were unable to detect any emission due to technical limitations of the instruments. The discovery of the radio reflecting ionosphere in 1902, led physicists to conclude that the layer would bounce any astronomical radio transmission back into space, making them undetectable. Karl Jansky made the discovery of the first astronomical radio source serendipitously in the early 1930s; as an engineer with Bell Telephone Laboratories, he was investigating static that interfered with short wave transatlantic voice transmissions.
Using a large directional antenna, Jansky noticed that his analog pen-and-paper recording system kept recording a repeating signal of unknown origin. Since the signal peaked about every 24 hours, Jansky suspected the source of the interference was the Sun crossing the view of his directional antenna. Continued analysis showed that the source was not following the 24-hour daily cycle of the Sun but instead repeating on a cycle of 23 hours and 56 minutes. Jansky discussed the puzzling phenomena with his friend and teacher Albert Melvin Skellett, who pointed out that the time between the signal peaks was the exact length of a sidereal day. By comparing his observations with optical astronomical maps, Jansky concluded that the radiation source peaked when his antenna was aimed at the densest part of the Milky Way in the constellation of Sagittarius, he concluded that since the Sun were not large emitters of radio noise, the strange radio interference may be generated by interstellar gas and dust in the galaxy.
Jansky announced his discovery in 1933. He wanted to investigate the radio waves from the Milky Way in further detail, but Bell Labs reassigned him to another project, so he did no further work in the field of astronomy, his pioneering efforts in the field of radio astronomy have been recognized by the naming of the fundamental unit of flux density, the jansky, after him. Grote Reber was inspired by Jansky's work, built a parabolic radio telescope 9m in diameter in his backyard in 1937, he began by repeating Jansky's observations, conducted the first sky survey in the radio frequencies. On February 27, 1942, James Stanley Hey, a British Army research officer, made the first detection of radio waves emitted by the Sun; that year George Clark Southworth, at Bell Labs like Jansky detected radiowaves from the sun. Both researchers were bound by wartime security surrounding radar, so Reber, not, published his 1944 findings first. Several other people independently discovered solar radiowaves, including E. Schott in Denmark and Elizabeth Alexander working on Norfolk Island.
At Cambridge University, where ionospheric research had taken place during World War II, J. A. Ratcliffe along with other members of the Telecommunications Research Establishment that had carried out wartime research into radar, created a radiophysics group at the university where radio wave emissions from the Sun were observed and studied; this early research soon branched out into the observation of other celestial radio sources and interferometry techniques were pioneered to isolate the angular source of the detected emissions. Martin Ryle and Antony Hewish at the Cavendish Astrophysics Group developed the technique of Earth-rotation aperture synthesis; the radio astronomy group in Cambridge went on to found the Mullard Radio Astronomy Observatory near Cambridge in the 1950s. During the late 1960s and early 1970s, as computers became capable of handling the computationally intensive Fourier transform inversions required, they used aperture synthesis to create a'One-Mile' and a'5 km' effective
The KGB, translated in English as Committee for State Security, was the main security agency for the Soviet Union from 1954 until its break-up in 1991. As a direct successor of preceding agencies such as Cheka, NKGB, NKVD and MGB, the committee was attached to the Council of Ministers, it was the chief government agency of "union-republican jurisdiction", acting as internal security and secret police. Similar agencies were constituted in each of the republics of the Soviet Union aside from Russia, consisted of many ministries, state committees and state commissions; the agency was a military service governed by army laws and regulations, in the same fashion as the Soviet Army or MVD Internal Troops. While most of the KGB archives remain classified, two online documentary sources are available, its main functions were foreign intelligence, counter-intelligence, operative-investigatory activities, guarding the State Border of the USSR, guarding the leadership of the Central Committee of the Communist Party and the Soviet Government and ensuring of government communications as well as combating nationalism and anti-Soviet activities.
In 1991, after the dissolution of the Soviet Union, the KGB was split into the Federal Security Service and the Foreign Intelligence Service of the Russian Federation. After breaking away from Georgia in the early 1990s with Russian help, the self-proclaimed Republic of South Ossetia established its own KGB. A Time magazine article in 1983 reported that the KGB was the world's most effective information-gathering organization, it operated legal and illegal espionage residencies in target countries where a legal resident gathered intelligence while based at the Soviet embassy or consulate, and, if caught, was protected from prosecution by diplomatic immunity. At best, the compromised spy was either returned to the Soviet Union or was declared persona non grata and expelled by the government of the target country; the illegal resident spied, unprotected by diplomatic immunity, worked independently of Soviet diplomatic and trade missions. In its early history, the KGB valued illegal spies more than legal spies, because illegal spies infiltrated their targets with greater ease.
The KGB residency executed four types of espionage: political, military-strategic, disinformation, effected with "active measures", counter-intelligence and security, scientific–technological intelligence. The KGB classified its spies as controllers; the false-identity or legend assumed by a USSR-born illegal spy was elaborate, using the life of either a "live double" or a "dead double". The agent substantiated his or her legend by living it in a foreign country, before emigrating to the target country, thus the sending of US-bound illegal residents via the Soviet embassy in Ottawa, Canada. Tradecraft included stealing and photographing documents, code-names, contacts and dead letter boxes, working as a "friend of the cause" or as agents provocateurs, who would infiltrate the target group to sow dissension, influence policy, arrange kidnappings and assassinations. Mindful of ambitious spy chiefs—and after deposing Premier Nikita Khrushchev—Secretary Leonid Brezhnev and the CPSU knew to manage the next over-ambitious KGB Chairman, Aleksandr Shelepin, who facilitated Brezhnev's palace coup d'état against Khrushchev in 1964.
With political reassignments, Shelepin protégé Vladimir Semichastny was sacked as KGB Chairman, Shelepin himself was demoted from chairman of the Committee of Party and State Control to Trade Union Council chairman. In the 1980s, the glasnost liberalisation of Soviet society provoked KGB Chairman Vladimir Kryuchkov to lead the August 1991 Soviet coup d'état attempt to depose President Mikhail Gorbachev; the thwarted coup d'état ended the KGB on 6 November 1991. The KGB's main successors are the FSB and the SVR; the GRU recruited the ideological agent Julian Wadleigh, who became a State Department diplomat in 1936. The NKVD's first US operation was establishing the legal residency of Boris Bazarov and the illegal residency of Iskhak Akhmerov in 1934. Throughout, the Communist Party USA and its General Secretary Earl Browder, helped NKVD recruit Americans, working in government and industry. Other important, low-level and high-level ideological agents were the diplomats Laurence Duggan and Michael Whitney Straight in the State Department, the statistician Harry Dexter White in the Treasury Department, the economist Lauchlin Currie, the "Silvermaster Group", headed by statistician Greg Silvermaster, in the Farm Security Administration and the Board of Economic Warfare.
Moreover, when Whittaker Chambers Alger Hiss's courier, approached the Roosevelt Government—to identify the Soviet spies Duggan and others—he was ignored. Hence, during the Second World War —at the Tehran and Potsdam conferences—Big Three Ally Joseph Stalin of the USSR, was better informed about the war affairs of his US and UK allies than they were about his. Soviet espionage was at its most successful in collecting scientific and technological intelligence about advan
The Baltic Sea is a marginal sea of the Atlantic Ocean, enclosed by Denmark, Finland, Lithuania, northeast Germany, Poland and the North and Central European Plain. The sea stretches from 53 ° N from 10 ° E to 30 ° E longitude. A mediterranean sea of the Atlantic, with limited water exchange between the two bodies, the Baltic Sea drains through the Danish islands into the Kattegat by way of the straits of Øresund, the Great Belt, the Little Belt, it includes the Gulf of Bothnia, the Bay of Bothnia, the Gulf of Finland, the Gulf of Riga, the Bay of Gdańsk. The Baltic Proper is bordered on its northern edge, at the latitude 60°N, by the Åland islands and the Gulf of Bothnia, on its northeastern edge by the Gulf of Finland, on its eastern edge by the Gulf of Riga, in the west by the Swedish part of the southern Scandinavian Peninsula; the Baltic Sea is connected by artificial waterways to the White Sea via the White Sea Canal and to the German Bight of the North Sea via the Kiel Canal. Administration The Helsinki Convention on the Protection of the Marine Environment of the Baltic Sea Area includes the Baltic Sea and the Kattegat, without calling Kattegat a part of the Baltic Sea, "For the purposes of this Convention the'Baltic Sea Area' shall be the Baltic Sea and the Entrance to the Baltic Sea, bounded by the parallel of the Skaw in the Skagerrak at 57°44.43'N."Traffic history Historically, the Kingdom of Denmark collected Sound Dues from ships at the border between the ocean and the land-locked Baltic Sea, in tandem: in the Øresund at Kronborg castle near Helsingør.
The narrowest part of Little Belt is the "Middelfart Sund" near Middelfart. Oceanography Geographers agree that the preferred physical border of the Baltic is a line drawn through the southern Danish islands, Drogden-Sill and Langeland; the Drogden Sill is situated north of Køge Bugt and connects Dragør in the south of Copenhagen to Malmö. By this definition, the Danish Straits are part of the entrance, but the Bay of Mecklenburg and the Bay of Kiel are parts of the Baltic Sea. Another usual border is the line between Falsterbo and Stevns Klint, Denmark, as this is the southern border of Øresund. It's the border between the shallow southern Øresund and notably deeper water. Hydrography and biology Drogden Sill sets a limit to Øresund and Darss Sill, a limit to the Belt Sea; the shallow sills are obstacles to the flow of heavy salt water from the Kattegat into the basins around Bornholm and Gotland. The Kattegat and the southwestern Baltic Sea have a rich biology; the remainder of the Sea is poor in oxygen and in species.
Thus, the more of the entrance, included in its definition, the healthier the Baltic appears. Tacitus called it Mare Suebicum after the Germanic people of the Suebi, Ptolemy Sarmatian Ocean after the Sarmatians, but the first to name it the Baltic Sea was the eleventh-century German chronicler Adam of Bremen; the origin of the latter name is speculative and it was adopted into Slavic and Finnic languages spoken around the sea likely due to the role of Medieval Latin in cartography. It might be connected to the Germanic word belt, a name used for two of the Danish straits, the Belts, while others claim it to be directly derived from the source of the Germanic word, Latin balteus "belt". Adam of Bremen himself compared the sea with a belt, stating that it is so named because it stretches through the land as a belt, he might have been influenced by the name of a legendary island mentioned in the Natural History of Pliny the Elder. Pliny mentions an island named Baltia with reference to accounts of Xenophon.
It is possible. Baltia might be derived from belt and mean "near belt of sea, strait." Meanwhile, others have suggested that the name of the island originates from the Proto-Indo-European root *bhel meaning "white, fair". This root and its basic meaning were retained in both Latvian. On this basis, a related hypothesis holds that the name originated from this Indo-European root via a Baltic language such as Lithuanian. Another explanation is that, while derived from the aforementioned root, the name of the sea is related to names for various forms of water and related substances in several European languages, that might have been associated with colors found in swamps, yet another explanation is that the name meant "enclosed sea, bay" as opposed to open sea. Some Swedish historians believe. In the Middle Ages the sea was known by a variety of names; the name Baltic Sea became dominant only after 1600. Usage of Baltic and similar terms to denote the region east of the sea started only in 19th century.
The Baltic Sea was known in ancient Latin language sources as Mare Suebicum or Mare Germanicum. Older native names in languages that used to be spoken on the shores of the sea or near it indicate the geographical location of the sea, or its size in relation to smaller gulfs, or tribes associated with it. In modern lang
The focal length of an optical system is a measure of how the system converges or diverges light. For an optical system in air, it is the distance over which collimated rays are brought to a focus. A system with a shorter focal length has greater optical power than one with a long focal length. In most photography and all telescopy, where the subject is infinitely far away, longer focal length leads to higher magnification and a narrower angle of view. On the other hand, in applications such as microscopy in which magnification is achieved by bringing the object close to the lens, a shorter focal length leads to higher magnification because the subject can be brought closer to the center of projection. For a thin lens in air, the focal length is the distance from the center of the lens to the principal foci of the lens. For a converging lens, the focal length is positive, is the distance at which a beam of collimated light will be focused to a single spot. For a diverging lens, the focal length is negative, is the distance to the point from which a collimated beam appears to be diverging after passing through the lens.
When a lens is used to form an image of some object, the distance from the object to the lens u, the distance from the lens to the image v, the focal length f are related by 1 f = 1 u + 1 v. The focal length of a thin lens can be measured by using it to form an image of a distant light source on a screen; the lens is moved. In this case 1/u is negligible, the focal length is given by f ≈ v. For a thick lens, or an imaging system consisting of several lenses or mirrors, the focal length is called the effective focal length, to distinguish it from other used parameters: Front focal length or front focal distance is the distance from the front focal point of the system to the vertex of the first optical surface. Back focal length or back focal distance is the distance from the vertex of the last optical surface of the system to the rear focal point. For an optical system in air, the effective focal length gives the distance from the front and rear principal planes to the corresponding focal points.
If the surrounding medium is not air the distance is multiplied by the refractive index of the medium. Some authors call these distances the front/rear focal lengths, distinguishing them from the front/rear focal distances, defined above. In general, the focal length or EFL is the value that describes the ability of the optical system to focus light, is the value used to calculate the magnification of the system; the other parameters are used in determining where an image will be formed for a given object position. For the case of a lens of thickness d in air, surfaces with radii of curvature R1 and R2, the effective focal length f is given by the Lensmaker's equation: 1 f =, where n is the refractive index of the lens medium; the quantity 1/f is known as the optical power of the lens. The corresponding front focal distance is: FFD = f, the back focal distance: BFD = f. In the sign convention used here, the value of R1 will be positive if the first lens surface is convex, negative if it is concave.
The value of R2 is negative if the second surface is convex, positive if concave. Note that sign conventions vary between different authors, which results in different forms of these equations depending on the convention used. For a spherically curved mirror in air, the magnitude of the focal length is equal to the radius of curvature of the mirror divided by two; the focal length is positive for a concave mi